阅读说明：本技术 印刷装置以及印刷方法 (Printing apparatus and printing method ) 是由 今村笃史 山田纯 北原将史 于 2020-03-04 设计创作，主要内容包括：本发明提供一种在印刷时能够适当设定在喷出油墨前输送纸张的量的印刷装置以及印刷方法。在印刷装置中,控制部以从基材的输送停止的状态起开始进行基材的输送、且在基材的输送距离达到喷出前输送距离之后开始印刷的方式对印刷部进行控制,在将下述条件(1)、(2)、(3)中的成为最长输送距离的条件的所述输送距离设为第一最长距离时,喷出前输送距离被设定为第一最长距离以上的值,其中,条件(1)为,直到被前驱动辊以及夹持辊夹持的基材的区域通过在基材的输送路径上被配置于最下游的印刷头为止的输送距离；条件(2)为,直到基材的输送速度成为等速为止的输送距离；条件(3)为,直到被输送的基材的张力稳定为止的输送距离。(The invention provides a printing device and a printing method capable of properly setting the amount of paper conveyed before ink is ejected during printing. In the printing apparatus, the control section controls the printing section so that the conveyance of the base material is started from a state in which the conveyance of the base material is stopped, and the printing is started after the conveyance distance of the base material reaches the pre-ejection conveyance distance, and when the conveyance distance which is a condition of the longest conveyance distance among the following conditions (1), (2), and (3) is set to a value equal to or greater than the first longest distance, the pre-ejection conveyance distance is set to a value equal to or greater than the first longest distance, where the condition (1) is a conveyance distance until a region of the base material sandwiched by the front driving roller and the nip roller passes through a print head disposed furthest downstream on the conveyance path of the base material; the condition (2) is a transport distance until the transport speed of the base material becomes constant; the condition (3) is a transport distance until the tension of the substrate to be transported is stabilized.)

1. A printing apparatus for conveying a substrate in a roll-to-roll manner, comprising:

a control unit;

a printing section having a printing head;

a front drive roller and a nip roller which are provided upstream of the printing section and which nip and convey the substrate,

the control unit controls the printing unit to start printing after the conveyance of the base material is started from a state in which the conveyance of the base material is stopped and the conveyance distance of the base material reaches a pre-ejection conveyance distance,

when the transport distance that is a condition for the longest transport distance among the following conditions (1), (2), and (3) is a first longest distance, the pre-ejection transport distance is set to a value equal to or greater than the first longest distance,

wherein the condition (1) is a transport distance until a region of the substrate nipped by the front drive roller and the pinch roller passes through the print head disposed most downstream on a transport path of the substrate;

the condition (2) is a transport distance until the transport speed of the base material becomes constant;

the condition (3) is a transport distance until the tension of the substrate being transported is stabilized.

2. Printing device according to claim 1,

a pretreatment unit that is disposed upstream of the printing unit on a transport path of the base material and performs pretreatment on the base material,

the printing apparatus has a first mode and a second mode,

the first mode is a mode in which the printing section performs printing on the base material without performing the pretreatment on the base material by the pretreatment section,

the second mode is a mode in which the printing section performs printing on the base material after the base material is subjected to the pretreatment using the pretreatment section,

when the first mode is selected, the pre-ejection transport distance is set to a value equal to or greater than the first longest distance,

when the second mode is selected, the pre-ejection transport distance is set to a value equal to or greater than a second longest distance when the transport distance that is a condition for the longest transport distance among the conditions (1) and (3) and the following condition (4) is set to the second longest distance,

the condition (4) is a conveyance distance from the start of conveyance of the base material to the time when the conveyance speed becomes constant + a conveyance distance from the time when the conveyance speed becomes constant to the time when the leading end portion of the region subjected to the pretreatment by the pretreatment unit passes through the print head disposed on the most downstream side.

3. Printing device according to claim 2,

as the printing conditions for performing printing, there is a table in which the presence or absence of the preprocessing, the acceleration until the transport speed of the base material is set to be constant, the printing speed set as the transport speed of the base material, and the pre-discharge transport distance according to the printing conditions are associated with each other,

the control unit sets the pre-ejection transport distance by comparing the printing conditions with the table when performing printing.

4. A printing method is a printing method for a printing apparatus including:

a control unit;

a printing section having a printing head;

a front drive roller and a nip roller which are provided upstream of the printing section and which nip and convey the substrate,

the printing device conveys the substrate in a roll-to-roll manner,

in the printing method,

the control unit controls the printing unit to start printing after the conveyance of the base material is started from a state in which the conveyance of the base material is stopped and the conveyance distance of the base material reaches a pre-ejection conveyance distance,

the printing method includes a first pre-ejection transport distance setting step in which the control unit sets the pre-ejection transport distance to a value equal to or greater than a first longest distance when the transport distance that is a condition of the longest transport distance among the following conditions (1), (2), and (3) is the first longest distance,

wherein the condition (1) is a transport distance until a region of the substrate nipped by the front drive roller and the pinch roller passes through the print head disposed most downstream on a transport path of the substrate;

the condition (2) is a transport distance until the transport speed of the base material becomes constant;

the condition (3) is a transport distance until the tension of the substrate being transported is stabilized.

5. The printing method of claim 4,

the printing apparatus includes a preprocessing unit that is disposed upstream of the printing unit on a transport path of the base material and performs preprocessing on the base material,

the printing apparatus has a first mode and a second mode,

the first mode is a mode in which the printing section performs printing on the base material without performing the pretreatment on the base material by the pretreatment section,

the second mode is a mode in which the printing section performs printing on the base material after the base material is subjected to the pretreatment using the pretreatment section,

the printing method comprises:

a first pre-ejection transport distance setting step of setting the control unit to a value equal to or greater than the first longest distance as the pre-ejection transport distance when the first mode is selected;

a second pre-discharge transport distance setting step of setting the control unit to a value equal to or greater than a second longest distance as the pre-discharge transport distance when the transport distance that is a condition of the longest transport distance among the conditions (1) and (3) and the following condition (4) is set to the second longest distance when the second mode is selected,

the condition (4) is a conveyance distance from the start of conveyance of the base material to the time when the conveyance speed becomes constant + a conveyance distance from the time when the conveyance speed becomes constant to the time when the leading end portion of the region subjected to the pretreatment by the pretreatment unit passes through the print head disposed on the most downstream side.

6. The printing method of claim 5,

as a printing condition for performing printing, there is a table in which the presence or absence of the preprocessing, the acceleration until the transport speed of the base material is set to be constant, the printing speed set as the transport speed of the base material, and the pre-ejection transport distance according to the printing condition are associated with each other,

the printing method includes the first pre-discharge transport distance setting step and the second pre-discharge transport distance setting step in which the control unit sets the pre-discharge transport distance by comparing the printing conditions with the table when performing printing.

Technical Field

The present invention relates to a printing apparatus and a printing method.

Background

Conventionally, in a roll-to-roll printing apparatus, when printing is performed, printing is started after paper conveyance is started and the conveyance speed is constant (see patent document 1).

However, when printing is started only in a state where the transport speed is constant, there is a concern that image quality may be degraded by printing in a region where paper is nipped. Further, there is a concern that the image quality may be degraded by printing under conditions where the tension is unstable. Further, when the surface of the paper is modified, there is a concern that the image quality may be degraded by printing in an area where the processing is unstable. Therefore, it is a problem to appropriately set a transport distance before ejection, which is an amount of transported paper before ink is ejected, at the time of printing.

Patent document 1: japanese patent laid-open publication No. 2017-170817

Disclosure of Invention

The printing apparatus according to the present application is a printing apparatus that transports a substrate in a roll-to-roll manner, and includes: a control unit; a printing section having a printing head; a front drive roller and a pinch roller which are provided upstream of the printing unit and which pinch and convey the base material, wherein the control unit controls the printing unit so that printing is started after conveyance of the base material is started from a state in which conveyance of the base material is stopped and a conveyance distance of the base material reaches a pre-discharge conveyance distance, and the pre-discharge conveyance distance is set to a value equal to or greater than a first longest distance when the conveyance distance that is a condition for the longest conveyance distance among the following conditions (1), (2), and (3) is set to the first longest distance,

wherein the condition (1) is a transport distance until a region of the substrate nipped by the front drive roller and the pinch roller passes through the print head disposed most downstream on a transport path of the substrate;

the condition (2) is a transport distance until the transport speed of the base material becomes constant;

the condition (3) is a transport distance until the tension of the substrate being transported is stabilized.

Preferably, the printing apparatus includes a preprocessing unit that is disposed upstream of the printing unit on a transport path of the base material and performs preprocessing on the base material, and the printing apparatus includes a first mode in which printing on the base material is performed by the printing unit without performing the preprocessing on the base material by the preprocessing unit, and a second mode in which printing on the base material is performed by the printing unit after performing the preprocessing on the base material by using the preprocessing unit, and the pre-ejection transport distance is set to a value equal to or greater than the first longest distance when the first mode is selected, and the condition (1) is set when the second mode is selected, (3) And a pre-ejection transport distance is set to a value equal to or greater than a second longest distance when the transport distance that is a condition of the longest transport distance in the following condition (4) is the second longest distance,

the condition (4) is a conveyance distance from the start of conveyance of the base material to the time when the conveyance speed becomes constant + a conveyance distance from the time when the conveyance speed becomes constant to the time when the leading end portion of the region subjected to the pretreatment by the pretreatment unit passes through the print head disposed on the most downstream side.

Preferably, in the printing apparatus, the printing apparatus includes a table in which the presence or absence of the preprocessing, the acceleration until the transport speed of the base material is set to be constant, the printing speed set as the transport speed of the base material, and the pre-discharge transport distance according to the printing condition are associated with each other as the printing condition when performing printing, and the control unit sets the pre-discharge transport distance by comparing the printing condition with the table when performing printing.

The printing method of the present application is a printing method of a printing apparatus including: a control unit; a printing section having a printing head; a front drive roller and a pinch roller that are provided upstream of the printing unit and that pinch and convey the base material, wherein the printing apparatus conveys the base material in a roll-to-roll manner, and wherein the control unit controls the printing unit to start printing after the conveyance of the base material is started from a state in which the conveyance of the base material is stopped and the conveyance distance of the base material has reached a pre-ejection conveyance distance, and wherein the printing method comprises a first pre-ejection conveyance distance setting step of setting the control unit as the pre-ejection conveyance distance to a value equal to or greater than a first longest distance when the conveyance distance that is a condition of the longest conveyance distance among conditions (1), (2), and (3) is set as the first longest distance,

wherein the condition (1) is a transport distance by which a region of the substrate held between the front drive roller and the grip roller passes through the print head disposed furthest downstream on a transport path of the substrate;

the condition (2) is a transport distance until the transport speed of the base material becomes constant;

the condition (3) is a transport distance until the tension of the substrate being transported is stabilized.

In the above printing method, it is preferable that the printing apparatus includes a preprocessing section that is disposed upstream of the printing section on a transport path of the base material and performs preprocessing on the base material, and has a first mode in which the printing section performs printing on the base material without performing the preprocessing on the base material by the preprocessing section, and a second mode in which the printing section performs printing on the base material after performing the preprocessing on the base material by using the preprocessing section, and the printing method includes: a first pre-ejection transport distance setting step of setting the control unit to a value equal to or greater than the first longest distance as the pre-ejection transport distance when the first mode is selected; a second pre-discharge transport distance setting step of setting the control unit to a value equal to or greater than a second longest distance as the pre-discharge transport distance when the transport distance that is a condition of the longest transport distance among the conditions (1) and (3) and the following condition (4) is set to the second longest distance when the second mode is selected,

the condition (4) is a conveyance distance from the start of conveyance of the base material to the time when the conveyance speed becomes constant + a conveyance distance from the time when the conveyance speed becomes constant to the time when the leading end portion of the region subjected to the pretreatment by the pretreatment unit passes through the print head disposed on the most downstream side.

Preferably, the printing method includes a table in which the presence or absence of the preprocessing, the acceleration until the transport speed of the base material is set to be constant, the printing speed set as the transport speed of the base material, and the pre-discharge transport distance according to the printing condition are associated with each other as the printing condition when performing printing, and the printing method includes the first pre-discharge transport distance setting step and the second pre-discharge transport distance setting step in which the control unit sets the pre-discharge transport distance by comparing the printing condition with the table when performing printing.

Drawings

Fig. 1 is a front view schematically showing an example of the structure of an apparatus to which a printer of the present invention is applied.

Fig. 2 is a block diagram showing an outline of an electrical configuration for controlling the printer.

Fig. 3 is a schematic diagram showing a relationship between time (distance) until each condition is achieved when corona treatment is not performed.

Fig. 4 is a schematic diagram showing a relationship between time (distance) until each condition is achieved in the case of performing corona treatment.

Fig. 5 is a diagram showing the results of conveying distances for respective conditions when experiments were performed by combining the respective printing conditions.

Detailed Description

An outline of a printing apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the printing apparatus is a printing apparatus that conveys a base material in a roll-to-roll manner. As an example thereof, the line inkjet printer 1 (hereinafter, simply referred to as the printer 1) is exemplified and explained.

The device configuration of the printer 1 of the present embodiment will be described.

Fig. 1 is a front view schematically showing the configuration of a printer 1 to which the present invention is applied.

As shown in fig. 1, in the printer 1, a single substrate S wound around the unwinding shaft 20 and the winding shaft 40 in a roll shape at both ends thereof is wound along the transport path R. The substrate S is printed while being conveyed in the conveying direction Q from the unwinding shaft 20 toward the winding shaft 40. The transport path R for transporting the substrate S is formed by moving the substrate S sequentially through rollers described later.

The types of the substrate S are broadly classified into paper and film. Specific examples of the paper include high-quality paper, high-gloss paper, art paper, and coated paper, and the film includes synthetic paper, PET (polyethylene terephthalate), PP (polypropylene), and the like.

The printer 1 includes, as a schematic configuration, an unwinding section 2 (unwinding region) for unwinding a substrate S from an unwinding shaft 20, a processing section 3 (processing region) for printing an image on the substrate S unwound from the unwinding section 2, and a winding section 4 (winding region) for winding the substrate S printed with the image by the processing section 3 on a winding shaft 40. In the following description, the surface on which an image is printed out of both surfaces of the base material S is referred to as a front surface, and the surface opposite thereto is referred to as a back surface.

The unwinding section 2 includes an unwinding shaft 20 around which an end portion of the substrate S is wound, a corona treater 21 as a pretreatment section for performing a treatment for modifying the surface of the substrate S drawn from the unwinding shaft 20, and a tension roller 22 (driven roller). The corona treatment machine 21 as a pretreatment unit is disposed upstream of a printing unit (printing heads 51 and 52) described later on the conveyance path R of the substrate S.

The unwinding shaft 20 winds and supports an end portion of the substrate S in a state where the surface of the substrate S faces outward. Then, the unwinding shaft 20 rotates clockwise in fig. 1, whereby the substrate S wound around the unwinding shaft 20 is unwound to the processing section 3 through the pretreatment section (corona treatment machine 21) and the tension roller 22.

The substrate S is wound on the unwinding spool 20 through the core tube 23 which is detachable from the unwinding spool 20. Therefore, when the substrate S on the unwinding spool 20 is used up, a new core tube 23 around which the rolled substrate S is wound can be attached to the unwinding spool 20, and the substrate S on the unwinding spool 20 can be replaced.

The corona treatment machine 21 as a pretreatment unit performs surface treatment for modifying the surface of the substrate S to be conveyed by irradiating the surface with corona discharge, thereby improving the wettability of the ink at the time of printing. The substrate S is mainly processed in the case of a thin film. Hereinafter, the case of performing corona discharge irradiation is referred to as corona treatment. The unwinding section 2 includes a conveying shaft 24 for conveying the substrate S in the corona treatment machine 21.

The unwinding shaft 20, the conveying shaft 24, and the tension roller 22 are configured to be movable in a width direction (a direction perpendicular to the paper surface of fig. 1) perpendicular to the conveying direction Q. The unwinding section 2 includes a steering mechanism 25, and the steering mechanism 25 suppresses meandering of the base material S by adjusting the positions of the unwinding shaft 20, the conveying shaft 24, and the tension roller 22 in the width direction (axial direction).

The steering mechanism 25 is composed of an edge sensor 251 and a width direction drive unit (not shown). The edge sensor 251 is provided on the downstream side of the tension roller 22 in the conveying direction Q so as to face the end of the base material S in the width direction, and detects the position of the end of the base material S in the width direction. Further, a width direction driving unit (not shown) moves the unwinding shaft 20, the conveying shaft 24, and the tension roller 22 in the width direction based on the detection result of the edge sensor 251. In this way, meandering of the base material S is thereby suppressed.

The processing section 3 is a member that supports the substrate S unwound from the unwinding section 2 by the platen cylinder 30, and performs processing appropriately by the functional sections 51, 52, 61, 62, and 63 arranged along the outer peripheral surface of the platen cylinder 30, thereby printing an image on the substrate S. In the processing section 3, a front driving roller 31 and a rear driving roller 32 are provided on the upstream side and the downstream side of the platen 30. The substrate S conveyed in the conveyance direction Q from the front drive roller 31 to the rear drive roller 32 is supported on the impression cylinder 30 and printed.

The front drive roller 31 has a plurality of minute protrusions formed by thermal spraying on the outer circumferential surface thereof, and winds the substrate S unwound from the unwinding section 2 from the back side. The front drive roller 31 rotates clockwise in fig. 1, and conveys the substrate S unwound from the unwinding section 2 to the downstream side in the conveying direction Q. Further, a pinch roller 31n is provided for the front drive roller 31. The nip roller 31n is in contact with the surface of the substrate S in a state of being biased toward the front driving roller 31 side, and sandwiches the substrate S between the nip roller and the front driving roller 31. This ensures friction between the front drive roller 31 and the substrate S, and enables the substrate S to be reliably conveyed by the front drive roller 31.

The platen roller 30 is supported by a support mechanism not shown so as to be capable of feeding

A cylindrical roller having a diameter of, for example, 400mm, which is rotatably supported in both the feeding direction Q and the reverse direction. Further, the impression cylinder 30 winds up the base material S conveyed from the front drive roller 31 to the rear drive roller 32 from the back side. The impression cylinder 30 receives a frictional force between itself and the base material S, and supports the base material S from the back side while rotating in the conveyance direction Q of the base material S.

In the processing section 3, driven rollers 33 and tension rollers 34 (driven rollers) for folding back the base material S are provided on both sides of a winding section for winding up the impression cylinder 30. The driven roller 33 winds the surface of the substrate S between the front driving roller 31 and the impression cylinder 30, thereby folding back the substrate S. On the other hand, the tension roller 34 winds the surface of the base material S between the impression cylinder 30 and the rear driving roller 32, thereby folding back the base material S. In this way, by turning back the base material S on the upstream side and the downstream side in the transport direction Q with respect to the platen cylinder 30, the winding section of the base material S that winds around the platen cylinder 30 can be ensured to be long.

The rear driving roller 32 has a plurality of minute protrusions formed by thermal spraying on its outer circumferential surface, and winds the base material S, which is conveyed from the platen 30 via the tension roller 34, from the back side. Then, the rear driving roller 32 rotates clockwise in fig. 1 to convey the substrate S to the take-up section 4.

Further, a nip roller 32n is provided for the rear driving roller 32. The nip roller 32n is in contact with the surface of the substrate S in a state of being biased toward the rear driving roller 32, and sandwiches the substrate S between the nip roller and the rear driving roller 32. This ensures friction between the rear driving roller 32 and the base material S, and the base material S can be reliably conveyed by the rear driving roller 32.

In this way, the base material S conveyed from the front driving roller 31 to the rear driving roller 32 is supported on the outer circumferential surface of the platen roller 30. The processing unit 3 is provided with a plurality of line-type printing heads 51 corresponding to different colors in order to print a color image on the surface of the base material S supported on the platen cylinder 30. The print head 51 and a print head 52 described later together constitute a printing unit.

In the present embodiment, as the print heads 51, five print heads 51(51W, 51Y, 51C, 51K, 51M) corresponding to white, yellow, cyan, black, and magenta are arranged in the conveyance direction Q in this color order. Each of the print heads 51 is opposed to the surface of the substrate S wound around the platen roller 30 with a slight gap therebetween, and ejects ink of a corresponding color (color ink) from a nozzle by an ink jet method. Then, each of the print heads 51 ejects ink onto the substrate S conveyed in the conveying direction Q, thereby forming a color image on the surface of the substrate S.

As the ink, a uv (ultraviolet) ink (photocurable ink) which is cured by irradiation of ultraviolet rays (light) is used. Therefore, in the processing section 3, UV irradiators 61, 62, and 63 are provided to cure and fix the ink on the substrate S. The ink curing is performed in two stages, i.e., pre-curing and main curing.

A UV irradiator 61 for main curing is disposed downstream of the white print head 51W and upstream of the yellow print head 51Y. The UV irradiator 61 for main curing is an irradiator which irradiates ultraviolet rays of a strong irradiation intensity to cure (main cure) the ink to such an extent that the wetting and diffusion of the ink is stopped. On the other hand, a UV irradiator 62 for precuring is disposed downstream of the print head 51Y for yellow, the print head 51C for cyan, the print head 51K for black, and the print head 51M for magenta. The UV irradiator 62 for precuring is an irradiator which irradiates ultraviolet rays having a relatively weak irradiation intensity compared with the UV irradiator 61 to cure (precure) the ink to such an extent that wetting and spreading of the ink is sufficiently slower than in the case of not irradiating the ultraviolet rays.

In this way, the UV irradiator 61 disposed downstream of the white printing head 51W completely cures the white ink, thereby stopping the wetting and spreading of the ink. The UV irradiator 62 disposed downstream of the magenta print head 51M performs precuring before the color inks discharged from the print heads 51Y, 51C, 51K, and 51M are mixed, thereby suppressing occurrence of color mixture. In this way, a color image is thereby formed on the base material S.

Further, the print head 52 is provided downstream of the UV irradiator 62 in the transport direction Q. The print head 52 is opposed to the surface of the substrate S wound around the impression cylinder 30 with a slight gap therebetween, and ejects transparent UV ink from nozzles onto the surface of the substrate S by an ink jet method. Thereby, the clear ink is further ejected to the color image formed by the print heads 51 of the five colors. The transparent ink is ejected over the entire surface of a color image, and gives the color image a texture such as a glossy or matte texture.

Further, a UV irradiator 63 is provided downstream of the print head 52 in the conveyance direction Q. The UV irradiator 63 is an irradiator that irradiates strong ultraviolet rays to main-cure the transparent ink discharged from the print head 52 together with the four color inks discharged from the print heads 51Y, 51C, 51K, and 51M and precured. Thereby, the four color inks and the clear ink can be fixed on the surface of the substrate S.

In this way, in the processing section 3, the ejection and curing of the ink are appropriately performed with respect to the base material S wound on the outer peripheral portion of the impression cylinder 30, thereby forming a color image coated with the clear ink. The substrate S on which the color image is formed is conveyed to the take-up section 4 by the rear driving roller 32.

The takeup unit 4 includes a takeup reel 40 for winding an end portion of the substrate S, and a tension roller 41 (driven roller) for winding the substrate S from the back side between the takeup reel 40 and the rear driving roller 32. The take-up shaft 40 takes up and supports an end portion of the substrate S with a surface of the substrate S facing outward. When the take-up reel 40 rotates clockwise in fig. 1, the substrate S conveyed from the rear driving roller 32 is taken up by the take-up reel 40 via the tension roller 41. Incidentally, the substrate S is wound around the winding shaft 40 via the core tube 42 that is attachable to and detachable from the winding shaft 40. Therefore, when the substrate S wound around the winding shaft 40 reaches the maximum allowable winding amount, the substrate S can be removed for each core tube 42.

Next, an electrical configuration for controlling the printer 1 will be explained.

Fig. 2 is a block diagram showing an outline of an electrical configuration for controlling the printer 1.

As shown in fig. 2, the printer 1 is provided with a control unit 100 for integrally controlling the respective units of the apparatus. The control Unit 100 is a computer including a CPU (Central Processing Unit) and a RAM (Random Access Memory).

The printer 1 is provided with a user interface 200 that functions as an interface between the control unit 100 and a user. The user interface 200 is constituted by an input device such as a mouse or a keyboard, and an output device such as a display. Therefore, the user can input a desired instruction to the control section 100 by operating the input device of the user interface 200, and can confirm the operating status of the printer 1 by confirming the output device of the user interface 200. The input device and the output device need not be separately configured, but may be integrally configured by a touch panel display or the like.

The control unit 100 controls the respective units of the printing heads 51 and 52, the UV irradiators 61, 62, and 63, the corona treatment machine 21, and the substrate transport system based on an instruction input by a user via the user interface 200 or an instruction received from another external device.

The control section 100 controls the ink ejection timing of each of the print heads 51 for forming a color image according to the conveyance of the substrate S. Specifically, the control of the ink ejection timing is performed based on the output (detected value) of the cylinder encoder E30 attached to the rotation shaft of the platen cylinder 30 and detecting the rotation position of the platen cylinder 30.

Since the platen roller 30 is driven to rotate as the substrate S is conveyed, the conveyance position of the substrate S can be grasped if the output of the roller encoder E30 that detects the rotational position of the platen roller 30 is referred to. Therefore, the control unit 100 generates a PTS (print timing signal) signal from the output of the drum encoder E30, and controls the ink ejection timing of each print head 51 based on the PTS signal, thereby causing the ink ejected from each print head 51 to land on the target position of the substrate S being conveyed, thereby forming a color image.

The timing at which the printing head 52 ejects the clear ink is also controlled by the control unit 100 based on the output of the drum encoder E30. This enables the clear ink to be ejected without fail to the color image formed by the plurality of print heads 51.

Further, the control unit 100 controls the timing of turning on and off the UV irradiators 61, 62, and 63 and the amount of irradiation light. Further, the control unit 100 controls on and off of the corona processor 21 or the irradiation amount of the corona irradiation based on an input operation from the user interface 200 performed by the user.

The control unit 100 has a function of controlling the conveyance of the substrate S. The conveyance control of the substrate S is mainly based on the steering control and the tension control of the substrate S. The steering control is executed by a steering mechanism 25 provided in the unwinding section 2. That is, the control section 100 performs feedback control of the position of the base material S in the width direction by adjusting the positions of the unwinding shaft 20, the conveying shaft 24, and the tension roller 22 in the width direction by the width direction driving section based on the detection result of the edge sensor 251. The tension control is performed by using motors described later connected to the unwinding shaft 20, the front drive roller 31, the rear drive roller 32, and the winding shaft 40 among the members constituting the substrate transport system.

In the tension control of the substrate S, the control unit 100 rotates the unwinding motor M20 that directly drives the unwinding shaft 20, and supplies the substrate S from the unwinding shaft 20 to the forward driving roller 31. At this time, the control unit 100 controls the torque of the unwinding motor M20 to adjust the tension (unwinding tension Ta) of the substrate S from the unwinding shaft 20 to the front drive roller 31. In other words, the control unit 100 controls the torque of the unwinding motor M20 to adjust the unwinding tension Ta in the region serving as the unwinding unit 2.

A tension sensor S22 for detecting the magnitude of the unwinding tension Ta is attached to the tension roller 22 disposed between the unwinding shaft 20 and the front drive roller 31. The tension sensor S22 can be formed of, for example, a load cell that detects the magnitude of the force received from the base material S. Then, the control unit 100 performs feedback control of the torque of the unwinding motor M20 based on the detection result (detection value) of the tension sensor S22, and adjusts the unwinding tension Ta of the base material S.

The control unit 100 also rotates a front drive motor M31 that drives the front drive roller 31 and a rear drive motor M32 that drives the rear drive roller 32. Thereby, the substrate S unwound from the unwinding section 2 passes through the processing section 3. At this time, speed control is performed with respect to the front drive motor M31, and torque control is performed with respect to the rear drive motor M32. That is, the control unit 100 performs feedback control of the rotation speed of the front drive motor M31 based on the output of the encoder of the front drive motor M31, and adjusts the conveyance speed of the base material S. Thus, the substrate S is conveyed by the front drive roller 31 at a print speed set as the conveyance speed of the substrate S when printing is performed. The control unit 100 calculates the transport position (transport distance) of the substrate S based on the output of the encoder of the front drive motor M31.

On the other hand, the control unit 100 controls the torque of the rear drive motor M32 to adjust the tension (process tension Tb) of the base material S from the front drive roller 31 to the rear drive roller 32. In other words, the control section 100 controls the torque of the rear drive motor M32 to adjust the process tension Tb in the region as the processing section 3.

A tension sensor S34 for detecting the magnitude of the process tension Tb is attached to the tension roller 34 disposed between the platen roller 30 and the rear driving roller 32. The tension sensor S34 can be formed of, for example, a load cell that detects the magnitude of the force received from the base material S. Then, the control unit 100 performs feedback control of the torque of the rear drive motor M32 based on the detection result (detection value) of the tension sensor S34 to adjust the processing tension Tb of the base material S.

Further, the control section 100 rotates the take-up motor M40 that directly drives the take-up reel 40, thereby taking up the substrate S conveyed by the rear driving roller 32 on the take-up reel 40. At this time, the control unit 100 controls the torque of the take-up motor M40 to adjust the tension (take-up tension Tc) of the substrate S from the rear driving roller 32 to the take-up reel 40. In other words, the control section 100 controls the torque of the take-up motor M40 to adjust the take-up tension Tc in the region serving as the take-up section 4.

A tension sensor S41 for detecting the winding tension Tc is attached to the tension roller 41 provided between the rear driving roller 32 and the take-up shaft 40. The tension sensor S41 can be formed of, for example, a load cell that detects the magnitude of the force received from the base material S. Then, the control unit 100 performs feedback control of the torque of the take-up motor M40 based on the detection result (detection value) of the tension sensor S41, thereby adjusting the take-up tension Tc of the base material S.

In particular, the control unit 100 adjusts the respective tensions Ta, Tb, and Tc to the printing tensions Ta1, Tb1, and Tc1 during the transport period in which the base material S is transported along with the execution of the printing operation. In the standby period in which the printing operation is not performed and the conveyance of the base material S is stopped, the control unit 100 adjusts the respective tensions Ta, Tb, and Tc to the standby tensions Ta2, Tb2, and Tc2, respectively.

Here, the standby tensions Ta2, Tb2, and Tc2 are lower than the printing tensions Ta1, Tb1, and Tc1 (Ta2 < Ta1, Tb2 < Tb1, and Tc2 < Tc1), respectively. The printing tensions Ta1, Tb1, and Tc1 may be referred to as transport tensions necessary for appropriately transporting the base material S.

As described above, in the present embodiment, the feed rate of the substrate S fed by the front drive roller 31 is adjusted by feedback-controlling the rotation speed of the front drive motor M31. The print speed of the present embodiment is of four types, and can be set to any one of the print speeds by the control unit 100, including an input instruction input by the user. In the present embodiment, four types of printing speeds, for example, 7.6m/min, 15m/min, 30m/min, and 50m/min, can be set as the printing speed. The printing speed may be referred to as a transport speed of the base material S when printing is performed.

In addition, in the present embodiment, two types of accelerations are provided as the acceleration for starting the conveyance from the conveyance stopped state and reaching the printing speed (set conveyance speed). The acceleration is set by inputting the attribute information of the base material S. The attribute information of the substrate S includes the width, thickness, material, and the like of the substrate S. The control unit 100 sets acceleration of any one of the two types by an input instruction of the attribute information of the base material S by the user. In the present embodiment, the acceleration can be set to 110.5mm/sec, for example, which is the acceleration when the sheet is conveyed with a normal tension²And 44.2mm/sec as acceleration when conveying at a low tension²These two categories.

The printer 1 further includes a storage unit 101 that stores various information. The storage unit 101 stores a program describing control procedures for implementing the various controls described above. Therefore, the control unit 100 reads a necessary program from the storage unit 101 and performs the various controls described above.

Further, the storage unit 101 stores a table for setting the amount (distance) by which the substrate S is conveyed before the ink is ejected after the conveyance of the substrate S is stopped. In addition, hereinafter, the amount of conveyance of the base material S before printing is performed after the conveyance of the base material S is started is referred to as a pre-ejection conveyance distance. In the present embodiment, the control unit 100 reads the table, and controls the printing unit so that the conveyance of the base material S is started and the printing is started after the conveyance distance of the base material S reaches the pre-ejection conveyance distance.

The table is a table showing a correspondence relationship between a print condition described later and a transport distance before ejection corresponding to the print condition. In the present embodiment, the printing conditions include the presence or absence of corona treatment, acceleration until the printing speed becomes constant, and a set conveyance speed.

Hereinafter, a method of setting the transport distance before ejection will be described.

First, a problem when printing is started under a condition where the transport distance before ejection is not appropriately secured will be described.

Specifically, when the substrate S is nipped and stopped by the front drive roller 31 and the pinch roller 31n, a component derived from the material of the pinch roller 31n that has oozed out from the pinch roller 31n adheres to a region of the substrate S nipped by the front drive roller 31 and the pinch roller 31n, and when the substrate S starts to be conveyed and is printed by the printing unit in the region where the component adheres, there is a problem that the quality of the printed image deteriorates. Hereinafter, the deterioration of the image quality occurring in the region of the substrate S nipped by the front drive roller 31 and the pinch roller 31n is referred to as a pinch mark.

Further, when printing is performed after the conveyance of the substrate S is started and before the conveyance speed becomes equal to the printing speed, there is a problem that the quality of the printed image deteriorates.

Further, when printing is performed before the conveyance of the base material S is started and the tension (printing tension Ta1, Tb1, Tc1) is stabilized, there is a problem that the quality of the printed image deteriorates.

In addition, when printing is performed in a region where the pretreatment by the pretreatment section, in this embodiment, the corona treatment by the corona treatment machine 21 is unstable, the quality of the printed image deteriorates. The region where the corona treatment is unstable means a region where the corona treatment is performed on the base material S before the conveyance speed becomes equal to the printing speed.

Therefore, in order to eliminate the above-described problems and to appropriately set the transport distance before ejection, the required conditions are described below. In other words, it is necessary to secure a transport distance represented by the following condition.

The condition is changed depending on whether or not the pretreatment (corona treatment) is performed on the substrate S by the pretreatment section (corona treatment machine 21) provided upstream of the front drive roller 31 in the transport direction Q (presence or absence of pretreatment). Although the corona treatment machine 21 is provided in the present embodiment, a case where printing is performed on the base material S by the printing section without performing corona treatment on the base material S is set as the first mode. Note that, a case where the base material S is printed by the printing portion after the base material S is corona-treated by the corona treatment machine 21 is set as the second mode.

The conditions in the first mode in which printing was performed without corona treatment were as follows.

The condition (1) is a transport distance until the region of the substrate S sandwiched between the front drive roller 31 and the pinch roller 31n passes through the print head (print head 52 in the present embodiment) disposed furthest downstream on the transport path R of the substrate S.

The condition (2) is a distance over which the substrate S is conveyed until the conveyance speed becomes constant after the conveyance of the substrate S is started.

The condition (3) is a distance over which the substrate S is conveyed until the tension of the conveyed substrate S is stabilized.

In the first mode, in order to appropriately set the transport distance before ejection, it is necessary to calculate the distance that is the longest distance among the above-described conditions (1), (2), and (3). When the maximum distance is set to the first maximum distance, the transport distance before ejection needs to be set to a value equal to or greater than the first maximum distance. The step of setting the pre-ejection transport distance to a value equal to or greater than the first longest distance by the control unit 100 is referred to as a first pre-ejection transport distance setting step in the present embodiment.

The conditions in the second mode in which printing was performed after the corona treatment were as follows.

The condition (1) is a transport distance until the region of the substrate S sandwiched between the front drive roller 31 and the pinch roller 31n passes through the print head (print head 52 in the present embodiment) disposed furthest downstream on the transport path R of the substrate S.

The condition (3) is a distance over which the substrate S is conveyed until the tension of the conveyed substrate S is stabilized.

The condition (4) is a transport distance until the distance over which the base material S is transported (same as the condition (2) in the first mode) until the transport speed becomes constant after the transport of the base material S is started) + the distance until the leading end of the region of the base material S, which is corona-treated by the corona treatment machine 21 after the transport speed becomes constant (after the acceleration is completed), passes through the print head 52 located furthest downstream on the transport path R of the base material S.

In the second mode, in order to appropriately set the transport distance before ejection, it is necessary to calculate the distance that is the longest distance among the above-described conditions (1), (3), and (4). When the longest distance is set to the second longest distance, the transport distance before ejection needs to be set to a value equal to or greater than the second longest distance. The step of setting the pre-ejection transport distance to a value equal to or greater than the second longest distance by the control unit 100 is referred to as a second pre-ejection transport distance setting step in the present embodiment.

Next, a method of determining the transport distance before ejection in the first mode (when the corona treatment is not performed) will be described.

Fig. 3 is a schematic diagram showing an example of the case where the corona treatment is not performed, and showing a relationship of time (distance) until each condition is achieved.

In fig. 3, the horizontal axis represents a time axis (T), and the vertical axis represents a speed axis (V). Fig. 3 shows a change in speed from a state where the substrate S is stopped to a state where the substrate S starts to be conveyed until the substrate S reaches a constant printing speed. As shown in fig. 3, the inclined line portion α indicates an acceleration region until the set conveyance speed is reached, and indicates a halfway acceleration at the set acceleration, and the flat line portion β indicates that the set conveyance speed has been reached.

In fig. 3, time t1 represents the time when the region of the substrate S nipped by the front drive roller 31 and the pinch roller 31n passes through the print head 52 furthest downstream on the conveyance path R of the substrate S while accelerating the substrate S. The time t2 represents a time when acceleration is completed in order to reach the set conveyance speed, in other words, in order to make the conveyance speed constant. The time t3 represents a time when the respective tensions (printing tensions Ta1, Tb1, Tc1) are stabilized. Further, the transport distance is calculated from the time and the speed change. Here, the time t1 corresponds to the condition (1), the time t2 corresponds to the condition (2), and the time t3 corresponds to the condition (3).

In the case of the first mode, in the example of fig. 3, the time (distance) until the tension of the conveyed base material S is stabilized is longest under the condition (3) corresponding to the time t3, and therefore the distance becomes the first longest distance. In order to avoid the occurrence of the failure, a value (conveyance amount) equal to or greater than the first longest distance is required as the conveyance distance before ejection.

Fig. 3 is a diagram showing an example of the first mode, and in the present embodiment, the condition for the first longest distance is made different by a combination of two types of accelerations and four types of printing speeds.

Next, a method of determining the transport distance before discharge in the second mode (when the corona treatment is performed) will be described.

Fig. 4 is a schematic diagram showing an example of the case where the corona treatment is performed, and showing a relationship of time (distance) until each condition is achieved.

In fig. 4, the horizontal axis represents a time axis (T) and the vertical axis represents a velocity axis (V), as in fig. 3. The change in the speed from the state where the substrate S is stopped to the state where the substrate S is stopped after the substrate S starts to be conveyed to the printing speed is shown. In fig. 4, as in fig. 3, the inclined line portion α indicates an acceleration region until the set conveyance speed is reached, and indicates a halfway point of acceleration at the set acceleration, and the flat line portion β indicates the set conveyance speed.

In fig. 4, time t4 represents the time during which the region of the substrate S nipped by the front drive roller 31 and the pinch roller 31n passes through the print head 52 furthest downstream on the conveyance path R of the substrate S during acceleration. The time t5 represents the time when the respective tensions (printing tensions Ta1, Tb1, Tc1) have stabilized. The time t6 represents the distance (distance until the acceleration is completed) until the transport speed becomes constant after the start of transport, and the time until the leading end of the region of the base material S, which has been corona-treated by the corona treatment machine 21, passes through the print head 52 located furthest downstream in the transport path R of the base material S after the transport speed becomes constant (after the acceleration is completed). Further, the transport distance is calculated from the time and the speed change. Here, the time t4 corresponds to the condition (1), the time t5 corresponds to the condition (3), and the time t6 corresponds to the condition (4).

In the case of the second mode, in the example of fig. 4, since the time (distance) in the condition (4) corresponding to the time t6 is the longest, the distance becomes the second longest distance. In order to avoid the occurrence of the failure, a value (conveyance amount) equal to or greater than the second longest distance is required as the conveyance distance before ejection.

Fig. 4 is a diagram showing an example of the second mode, and in the present embodiment, the condition for the second longest distance is made different by a combination of two types of accelerations and four types of printing speeds.

Next, the inventors will explain the results of experiments performed by combining the printing conditions in the first mode and the second mode.

Fig. 5 is a diagram showing the results of conveying distances for respective conditions when experiments were performed by combining the respective printing conditions.

The printing conditions to be combined include three conditions, i.e., corona treatment, acceleration until the transport speed is set to a constant speed, and printing speed. Specifically, the printing conditions are classified into corona treatment and non-corona treatment. In addition, the first mode is used when there is no corona treatment, and the second mode is used when there is a corona treatment. In acceleration, the normal conveyance (110.5 mm/sec)²) Low tension transport (44.2 mm/sec)²) These two categories. The printing speed was 7.6m/min, 15m/min, 30m/min, and 50 m/min.

Accordingly, fig. 5 shows the results of determining the transport distances for realizing the conditions (1), (2), and (3) in the first mode and determining the transport distances for realizing the conditions (1), (3), and (4) in the second mode, while combining the above-described printing conditions. In fig. 5, the corona treatment is classified into two types according to the presence or absence of the corona treatment. That is, the corona treatment is classified into a first mode and a second mode according to the presence or absence of the corona treatment. Next, for each mode, two types are classified according to the acceleration. Next, the acceleration is classified into four types according to the printing speed. Therefore, a total of 16 types of combinations is obtained. Symbols a to P are assigned to the 16 combinations, and the combinations a to P will be described below.

Here, the conditions (1) to (4) will be described again.

The conditions in the first mode are conditions (1), (2), and (3).

The condition (1) is a transport distance until the region of the substrate S sandwiched by the front drive roller 31 and the pinch roller 31n passes through the print head (print head 52 in the present embodiment) located furthest downstream on the transport path R of the substrate S. The condition (2) is a distance over which the base material S is conveyed during a period from when conveyance is started until the conveyance speed becomes constant. The condition (3) is a distance over which the substrate S is conveyed until the tension of the conveyed substrate S is stabilized.

The conditions in the second mode are conditions (1), (3), and (4).

The conditions (1) and (3) are the same as the first mode. The condition (4) is a distance (the same as the condition (2) in the first mode) by which the base material S is conveyed during a period from when the conveyance is started until the conveyance speed becomes constant) + a conveyance distance after the conveyance speed becomes constant (after the acceleration is completed) until the leading end portion of the region of the base material S subjected to the corona treatment by the corona treatment machine 21 passes through the print head 52 located furthest downstream on the conveyance path R of the base material S.

In fig. 5, combinations a to H become combinations in the first mode. Further, the combinations I to P become combinations in the second mode. For example, a method of observing the figure under combination a will be described.

In combination A, corona treatment is shown as none (first mode), acceleration is shown as normal transport (110.5 mm/sec)²) And a printing speed of 7.6 m/min. The result (transport distance) in the combination a was 1.85m under the condition (1), 0.09m under the condition (2), and 0.99m under the condition (3).

As a result, when the distance that is the condition of the longest distance (transport distance) among the conditions (1), (2), and (3) is the first longest distance, it is known that the first longest distance is 1.85m of the condition (1). Therefore, it is understood that the transport distance before ejection must be set to a value of 1.85m or more, which is the first longest distance. Thus, the transport distance before ejection can be set to 1.85m, which is the same as the first longest distance.

However, in fig. 5, the column on the right side of the condition (4) shows the transport distance before ejection recommended by the inventors in the case where the measurement error and the like are included. As shown in fig. 5, in the combination a, the transport distance before ejection recommended by the inventors is set to 2.0 m. The value is 1.85m or more.

In the present embodiment, the pre-ejection transport distance in the first mode is a value equal to or greater than the first longest distance and equal to or greater than the first longest distance, and is a value in units of 0.5 m. The transport distance before ejection in the second mode described later is also a value equal to or greater than the second longest distance and equal to or greater than the second longest distance, and is a value in units of 0.5 m. The transport distance before ejection is a value close to the first longest distance and the second longest distance. In addition, the reason for this is to reduce the complexity of setting a unit to be smaller than that of 0.5m, and to simplify the setting.

As a result of the other combinations in the first mode, in the combination B, the first longest distance becomes 1.85m of the condition (1), and the pre-ejection transport distance in this case becomes 2.0 m. In combination C, the first longest distance becomes 3.84m of condition (3), and the pre-ejection transport distance in this case becomes 4.0 m. In combination D, the first longest distance is 5.77m of condition (3), and the pre-ejection transport distance in this case is 6.0 m.

In combination E, the first longest distance becomes 1.85m of condition (1), and the pre-ejection transport distance in this case becomes 2.0 m. In the combination F, the first longest distance becomes 1.85m of the condition (1), and the pre-ejection transport distance in this case becomes 2.0 m. In the combination G, the first longest distance becomes 3.57m of the condition (2), and the pre-ejection transport distance in this case becomes 4.0 m. In the combination H, the first longest distance becomes 9.87m of the condition (2), and the pre-ejection transport distance in this case becomes 10.0 m.

As a result of the combination in the second mode, in the combination I, the second longest distance becomes 2.9m of the condition (4), and the pre-ejection transport distance in this case becomes 3.0 m. In combination J, the second longest distance becomes 3.16m of condition (4), and the pre-ejection transport distance in this case becomes 3.5 m. In the combination K, the second longest distance becomes 4.23m of the condition (4), and the pre-ejection transport distance in this case becomes 4.5 m. In the combination L, the second longest distance becomes 6.76m of the condition (4), and the pre-ejection transport distance in this case becomes 7.0 m.

In the combination M, the second longest distance becomes 3.03M of the condition (4), and the pre-ejection transport distance in this case becomes 3.5M. In combination N, the second longest distance becomes 3.70m of condition (4), and the pre-ejection transport distance in this case becomes 4.0 m. In the combination O, the second longest distance becomes 6.38m of the condition (4), and the pre-ejection transport distance in this case becomes 6.5 m. In the combination P, the second longest distance becomes 12.68m of the condition (4), and the pre-ejection transport distance in this case becomes 13.0 m.

As shown in fig. 5, the pre-ejection transport distance can be determined so as to correspond to the combination of the respective printing conditions.

Next, an operation including the control unit 100 in the case where the conveyance of the substrate S is started from a state where the conveyance of the substrate S is stopped in order to perform printing will be described.

The printer 1 stores a table in which the above-described printing conditions are associated with the pre-ejection transport distances corresponding to the printing conditions in the storage unit 101. Alternatively, the diagram shown in fig. 5 represents a table.

The user operates the input device of the user interface 200 to input or select the attribute information, acceleration, and printing speed of the substrate S before starting conveyance. The control unit 100 reads the table, and selects an appropriate combination of printing conditions for the base material S to be printed based on the input attribute information, acceleration, and printing speed. Then, the control section 100 sets the pre-ejection transport distance corresponding to the selected combination. In other words, the control unit 100 compares the printing conditions with the table to set the transport distance before ejection.

The control unit 100 performs a step of setting the pre-ejection transport distance by referring to the printing conditions and the table, and performs a first pre-ejection transport distance setting step in the first mode and a second pre-ejection transport distance setting step in the second mode. Specifically, the first pre-ejection transport distance setting step is a step in the first mode, and the control unit 100 selects a combination of the combinations a to H shown in fig. 5 based on the attribute information, the acceleration, and the printing speed, and sets the pre-ejection transport distance corresponding to the selected combination. The second pre-discharge transport distance setting step is a step in the second mode, and the control unit 100 selects a combination of the combinations I to P shown in fig. 5 based on the attribute information, the acceleration, and the printing speed, and sets the pre-discharge transport distance corresponding to the selected combination.

Thus, when receiving an instruction input for starting printing, the control section 100 controls the motors (M20, M31, M32, M40), the tension sensors (S22, S34, S41), the corona processor 21, and the like, based on the printing condition selected in the first pre-ejection transport distance setting step or the second pre-ejection transport distance setting step and the set pre-ejection transport distance, and starts transport of the base material S. Then, the control section 100 determines whether or not the transport distance of the base material S reaches the pre-ejection transport distance. When the print condition is reached, the control unit 100 controls the print heads 51 and 52, the UV irradiators 61, 62, and 63, and the like as the printing unit to start printing.

As described above, according to the printer 1 and the printing method of the printer 1 of the present embodiment, the following effects can be obtained.

According to the printer 1 of the present embodiment, the control unit 100 sets the pre-ejection transport distance to a value equal to or greater than the first longest distance when the distance that is the longest distance among the conditions (1), (2), and (3) is set to the first longest distance. Then, the control section 100 starts the conveyance of the substrate S from a state in which the conveyance of the substrate S is stopped, and controls the printing section to start printing after the conveyance distance of the substrate S reaches the pre-ejection conveyance distance.

Accordingly, since the transport distance before discharge is equal to or longer than the distance until the region of the base material S sandwiched between the front drive roller 31 and the pinch roller 31n passes through the most downstream print head 52 on the transport path R of the base material S as in condition (1), even when a component derived from the material of the pinch roller 31n adheres to the base material S, printing is performed after the region to which the component adheres passes through the most downstream print head 52 on the transport path R of the base material S, and thus, occurrence of pinch marks can be prevented. Further, since the transport distance before ejection is equal to or longer than the distance until the transport is started and the transport speed is equal to the constant speed as in the condition (2), the quality of the printed image can be prevented from being degraded. Further, since the transport distance before ejection is equal to or longer than the distance until the tensions Ta1, Tb1, and Tc1 of the substrate S being transported are stabilized as in condition (3), the quality of the printed image can be prevented from being degraded. Therefore, at the time of printing, the transport distance before ejection, which is the amount of the transport base material S before ink ejection, can be appropriately set, and therefore, the quality of the printed image can be prevented from being degraded.

The printer 1 according to the present embodiment has a second mode in which the corona treatment machine 21 as a preprocessing unit is provided upstream of the printing unit, and the printing unit performs printing on the substrate S after the corona treatment of the substrate S. When the second mode is selected, the distance that is the longest distance among the conditions (1), (3), and (4) is set to the second longest distance, and the pre-ejection transport distance is set to a value equal to or greater than the second longest distance.

Accordingly, since the transport distance before discharge is equal to or longer than the distance until the region of the base material S sandwiched by the front drive roller 31 and the pinch roller 31n passes through the print head 52 located furthest downstream on the transport path R of the base material S as in condition (1), even when a component derived from the material of the pinch roller 31n adheres to the base material S, the region to which the component adheres passes through the print head 52 located furthest downstream on the transport path R of the base material S and printing is performed, and therefore, the occurrence of pinch marks can be prevented. Further, since the transport distance before ejection is equal to or longer than the distance until the tensions Ta1, Tb1, and Tc1 of the substrate S being transported are stabilized as in condition (3), the quality of the printed image can be prevented from being degraded. Further, the transport distance before ejection is equal to or longer than the distance after the transport is started until the transport speed becomes constant as in condition (4) and the distance after the transport speed becomes constant (after acceleration is completed) until the leading end portion of the region of the base material S subjected to corona treatment by the corona treatment machine 21 passes through the print head 52 located furthest downstream on the transport path R of the base material S, so that the quality of the printed image can be prevented from being degraded. Therefore, even when the corona treatment is performed by the corona treatment machine 21, the transport distance before ejection, which is the amount of the transport base material S before ink ejection, can be appropriately set at the time of printing, and thus the quality of the printed image can be prevented from being degraded. In addition, when the first mode in which the corona treatment is not performed on the base material S is selected, the transport distance before ejection may be set to a value equal to or greater than the first longest distance as described above, and the quality of the printed image may be prevented from being degraded.

The printer 1 according to the present embodiment includes, as printing conditions for performing printing, a table in which the presence or absence of corona treatment by the corona treatment machine 21, the acceleration and the printing speed until the speed is set to a constant speed, and the transport distance before ejection corresponding to the printing conditions are associated with each other. When printing is performed, the control unit 100 compares the printing conditions with the table to set the transport distance before ejection.

Accordingly, since the control unit 100 compares the print condition with the table based on the attribute information and sets the optimum pre-ejection transport distance by inputting the attribute information of the base material S by the user, it is possible to prevent the quality of the printed image from being degraded and to improve the convenience of the printer 1.

According to the printer 1 of the present embodiment, in the first mode, the distance that is the longest distance among the conditions (1), (2), and (3) is set to the first longest distance, and the pre-ejection transport distance is set to a value equal to or greater than the first longest distance. The value equal to or greater than the first longest distance is equal to or greater than the first longest distance, and is a value in units of 0.5 m. In addition, the pre-ejection transport distance is set to a value close to the first longest distance by 0.5 m. In the second mode, the distance that is the longest distance among the conditions (1), (3), and (4) is set to the second longest distance, and the pre-ejection transport distance is set to a value equal to or greater than the second longest distance. The value is equal to or greater than the second longest distance and is a value in units of 0.5 m. In addition, the pre-ejection transport distance is set to a value close to the second longest distance by 0.5 m. By setting the conveyance distance before ejection in this manner, broke can be reduced as much as possible.

According to the printing method of the printer 1 of the present embodiment, the control unit 100 includes a first pre-ejection transport distance setting step of setting the distance that is the longest distance among the conditions (1), (2), and (3) as the first longest distance, as the pre-ejection transport distance, as a value equal to or greater than the first longest distance. Then, the control section 100 starts the conveyance of the substrate S from a state in which the conveyance of the substrate S is stopped, and controls the printing section to start printing after the conveyance distance of the substrate S reaches the pre-ejection conveyance distance.

Accordingly, since the transport distance before ejection is set to a distance or more specified by the conditions (1), (2), and (3), it is possible to prevent the quality of the printed image from being degraded. Therefore, the transport distance before ejection, which is the amount of the transport base material S before ink ejection, can be appropriately set at the time of printing.

The printing method of the printer 1 according to the present embodiment has a second mode in which the corona treatment machine 21 as a preprocessing unit is provided upstream of the printing unit, and the printing unit performs printing on the substrate S after the corona treatment is performed on the substrate S. When the second mode is selected, the method includes a second pre-ejection transport distance setting step of setting, as the pre-ejection transport distance, a value equal to or greater than a second longest distance when the distance that is the longest distance among the conditions (1), (3), and (4) is the second longest distance. When the second mode is selected, the pre-discharge transport distance is set to a distance or more specified by the conditions (1), (3), and (4) in the second pre-discharge transport distance setting step, and therefore, the quality of the printed image can be prevented from being degraded. Therefore, even when the corona treatment is performed by the corona treatment machine 21, the transport distance before ejection, which is the amount of the transport base material S before ink ejection, can be appropriately set at the time of printing. In addition, when the first mode in which the corona treatment is not performed on the base material S is selected, since the first pre-ejection conveying distance setting step of setting the value equal to or greater than the first longest distance as the pre-ejection conveying distance is provided as described above, it is possible to prevent the quality of the printed image from being degraded.

The printing method of the printer 1 according to the present embodiment includes a table in which the presence or absence of the corona treatment by the corona treatment machine 21, the acceleration and the printing speed until the speed is set to be constant, and the transport distance before ejection corresponding to the printing conditions are associated with each other as the printing conditions when performing printing. The control unit 100 further includes a first pre-discharge conveyance distance setting step and a second pre-discharge conveyance distance setting step of setting the pre-discharge conveyance distance by matching the printing conditions with the table when performing printing.

Accordingly, since the control unit 100 compares the print condition with the table based on the attribute information by inputting the attribute information, the acceleration, and the print speed (transport speed) of the base material S by the user, and sets the optimum transport distance before ejection, it is possible to prevent the quality of the printed image from being degraded and to improve the convenience of the printer 1.

The present invention is not limited to the above-described embodiments, and various modifications, improvements, and the like can be added to the above-described embodiments. Hereinafter, modifications will be described.

Modification example 1

In the printer 1 of the present embodiment, the transport distance before ejection is equal to or longer than the first longest distance and is set to a value in units of 0.5m in the first mode. In the second mode, the value is equal to or greater than the second longest distance and is a value in units of 0.5 m. However, the determination method of the value is free, and may be a value set to at least the first longest distance or more and the second longest distance or more.

Further, the condition (1) is a transport distance until the region of the substrate S sandwiched by the front drive roller 31 and the nip roller 31n passes through the print head (in the present embodiment, the print head 52) located furthest downstream on the transport path R of the substrate S, but may be a transport distance up to the print head 51 located furthest upstream on the transport path R among the print heads 51 that discharge the ink color used in the image to be printed, instead of the print head located furthest downstream. For example, when white ink is used for an image to be printed, the print head on the most upstream side is the print head 51W, and in this case, the condition (1) is a transport distance until the region of the substrate S sandwiched by the front drive roller 31 and the pinch roller 31n passes through the print head 51W. Further, the condition (4) is a distance (the same as the condition (2) in the first mode) by which the base material S is conveyed until the conveyance speed becomes constant after the conveyance is started, and a conveyance distance by which the tip end portion of the region of the base material S, which is corona-treated by the corona treatment machine 21, passes through the print head 52 located furthest downstream on the conveyance path R of the base material S after the conveyance speed becomes constant (after the acceleration is ended), but may be a conveyance distance by which the print head 51 located furthest upstream on the conveyance path R, among the print heads 51 that eject the ink color used in the image to be printed, passes instead of the print head furthest downstream. For example, in the case where white ink is used for an image to be printed, the print head on the most upstream side is the print head 51W, and in this case, the condition (4) is a distance (the same as the condition (2) in the first mode) that the substrate S is conveyed during a period from when conveyance is started until the conveyance speed becomes constant, and a conveyance distance until the leading end of the region of the substrate S subjected to corona treatment by the corona treatment machine 21 passes through the print head 51W after the conveyance speed becomes constant (after acceleration is completed).

Although the printer 1 of the present embodiment exemplifies a line-type inkjet printer, the printer is not limited to this, and may be a serial-type inkjet printer.

Hereinafter, the contents derived from the above embodiments will be described.

The printing device is a printing device for conveying a base material in a roll-to-roll manner, and is provided with: a control unit; a printing section having a printing head; a front drive roller and a pinch roller which are provided upstream of the printing unit and which pinch and convey the base material, wherein the control unit controls the printing unit so that printing is started after conveyance of the base material is started from a state in which conveyance of the base material is stopped and a conveyance distance of the base material reaches a pre-discharge conveyance distance, and the pre-discharge conveyance distance is set to a value equal to or greater than a first longest distance when the conveyance distance that is a condition for the longest conveyance distance among the following conditions (1), (2), and (3) is set to the first longest distance,

wherein the condition (1) is a transport distance until a region of the substrate nipped by the front drive roller and the pinch roller passes through the print head disposed most downstream on a transport path of the substrate;

the condition (2) is a transport distance until the transport speed of the base material becomes constant;

the condition (3) is a transport distance until the tension of the substrate being transported is stabilized.

According to this configuration, since the transport distance before discharge is equal to or longer than the transport distance until the region of the base material sandwiched by the front drive roller and the pinch roller passes through the print head disposed furthest downstream on the transport path of the base material S as in condition (1), even when a component derived from the material of the pinch roller adheres to the base material, for example, printing is performed after the region to which the component adheres passes through the print head furthest downstream on the transport path of the base material, and therefore, a reduction in the quality of a printed image can be prevented. Further, since the transport distance before ejection is equal to or longer than the transport distance after starting transport as in condition (2) until the transport speed of the base material becomes constant, it is possible to prevent the quality of the printed image from being degraded. Further, since the transport distance before ejection is equal to or longer than the transport distance until the tension of the conveyed base material is stabilized as in condition (3), it is possible to prevent the quality of the printed image from being degraded. Therefore, the transport distance before ejection, which is the amount of the transport base material before ink ejection, can be appropriately set at the time of printing, and therefore, the quality of the printed image can be prevented from being degraded.

Preferably, the printing apparatus includes a preprocessing unit that is disposed upstream of the printing unit on a transport path of the base material and performs preprocessing on the base material, and the printing apparatus includes a first mode in which printing on the base material is performed by the printing unit without performing the preprocessing on the base material by the preprocessing unit, and a second mode in which printing on the base material is performed by the printing unit after performing the preprocessing on the base material by using the preprocessing unit, and the pre-ejection transport distance is set to a value equal to or greater than the first longest distance when the first mode is selected, and the condition (1) is set when the second mode is selected, (3) And a pre-ejection transport distance is set to a value equal to or greater than a second longest distance when the transport distance that is a condition of the longest transport distance in the following condition (4) is the second longest distance,

the condition (4) is a conveyance distance from the start of conveyance of the base material to the time when the conveyance speed becomes constant + a conveyance distance from the time when the conveyance speed becomes constant to the time when the leading end portion of the region subjected to the pretreatment by the pretreatment unit passes through the print head disposed on the most downstream side.

According to this configuration, when the second mode is selected, the distance of conveyance before ejection is equal to or longer than the distance until the region of the base material nipped by the front drive roller and the pinch roller passes through the most downstream print head on the conveyance path of the base material as in condition (1), and therefore, even when a component derived from the material of the pinch roller adheres to the base material, for example, printing is performed after the region to which the component adheres passes through the most downstream print head on the conveyance path of the base material, and therefore, it is possible to prevent the quality of the printed image from being degraded. Further, since the transport distance before ejection is equal to or longer than the transport distance until the tension of the conveyed base material is stabilized as in condition (3), it is possible to prevent the quality of the printed image from being degraded. Further, the transport distance before ejection is equal to or longer than the transport distance between the start of transport of the base material and the transport speed after the start of transport of the base material and the transport speed being equal to or greater than the transport distance between the end of the area of the base material where the pretreatment is performed by the pretreatment unit and the print head disposed furthest downstream on the transport path of the base material after the transport speed being equal to or equal to the transport speed as in the condition (4), and therefore, the quality of the printed image can be prevented from being degraded. Therefore, even when the pretreatment is performed using the pretreatment section, the pre-ejection transport distance, which is the amount of the transport base material before the ink is ejected, can be appropriately set at the time of printing, and therefore, the quality of the printed image can be prevented from being degraded. In addition, when the first mode in which the base material is not subjected to the pretreatment is selected, the pre-ejection transport distance may be set to a value equal to or greater than the first longest distance as described above, and thus the quality of the printed image can be prevented from being degraded.

Preferably, in the printing apparatus, the printing apparatus includes a table in which the presence or absence of the preprocessing, the acceleration until the transport speed of the base material is set to be constant, the printing speed set as the transport speed of the base material, and the pre-discharge transport distance according to the printing condition are associated with each other as the printing condition when performing printing, and the control unit sets the pre-discharge transport distance by comparing the printing condition with the table when performing printing.

According to this configuration, since the control unit compares the printing condition with the table based on the attribute information by inputting the attribute information of the base material by the user and sets the optimum transport distance before ejection, it is possible to prevent the quality of the printed image from being degraded and to improve the convenience of the printing apparatus.

The printing method is characterized by being a printing method for a printing apparatus comprising: a control unit; a printing section having a printing head; a front drive roller and a pinch roller that are provided upstream of the printing unit and that pinch and convey the base material, wherein the printing apparatus conveys the base material in a roll-to-roll manner, and wherein the control unit controls the printing unit to start printing after the base material is conveyed from a state in which the conveyance of the base material is stopped and a conveyance distance of the base material reaches a pre-ejection conveyance distance, and wherein the printing method comprises a first pre-ejection conveyance distance setting step of setting the control unit as the pre-ejection conveyance distance to a value equal to or greater than the first maximum distance when the conveyance distance that is a condition of the maximum conveyance distance among the following conditions (1), (2), and (3) is set as the first maximum distance,

wherein the condition (1) is a transport distance until a region of the substrate nipped by the front drive roller and the pinch roller passes through the print head disposed most downstream on a transport path of the substrate;

the condition (2) is a transport distance until the transport speed of the base material becomes constant;

the condition (3) is a transport distance until the tension of the substrate being transported is stabilized.

According to this configuration, since the pre-ejection transport distance is set to be equal to or longer than the transport distance defined by the conditions (1), (2), and (3) in the first pre-ejection transport distance setting step, it is possible to prevent a reduction in the quality of the printed image. Therefore, the transport distance before ejection, which is the amount of the transport base material before ink ejection, can be appropriately set at the time of printing.

Preferably, in the printing method, the printing apparatus includes a preprocessing section that is disposed upstream of the printing section on a transport path of the base material and performs preprocessing on the base material, and includes a first mode in which the printing section performs printing on the base material without performing the preprocessing on the base material by the preprocessing section, and a second mode in which the printing section performs printing on the base material after performing the preprocessing on the base material by using the preprocessing section, and the printing method includes: a first pre-ejection transport distance setting step of setting the control unit to a value equal to or greater than the first longest distance as the pre-ejection transport distance when the first mode is selected; a second pre-discharge transport distance setting step of setting the control unit to a value equal to or greater than a second longest distance as the pre-discharge transport distance when the transport distance that is a condition of the longest transport distance among the conditions (1) and (3) and the following condition (4) is set to the second longest distance when the second mode is selected,

the condition (4) is a conveyance distance from the start of conveyance of the base material to the time when the conveyance speed becomes constant + a conveyance distance from the time when the conveyance speed becomes constant to the time when the leading end portion of the region subjected to the pretreatment by the pretreatment unit passes through the print head disposed on the most downstream side.

According to this configuration, when the second mode is selected, the pre-ejection transport distance is set to be equal to or longer than the transport distance defined by the conditions (1), (3), and (4) in the second pre-ejection transport distance setting step, and therefore, the quality of the printed image can be prevented from being degraded. Therefore, even when the pretreatment is performed using the pretreatment unit, the transport distance before ejection, which is the amount of the transport base material before the ink is ejected, can be appropriately set at the time of printing. Further, when the first mode in which the base material is not subjected to the pretreatment is selected, as described above, the first pre-ejection transport distance setting step of setting the pre-ejection transport distance to a value equal to or greater than the first longest distance is provided, and therefore, the quality of the printed image can be prevented from being degraded.

Preferably, the printing method includes a table in which the presence or absence of the preprocessing, the acceleration until the transport speed of the base material is set to be constant, the printing speed set as the transport speed of the base material, and the pre-discharge transport distance according to the printing condition are associated with each other as the printing condition when performing printing, and the printing method includes the first pre-discharge transport distance setting step and the second pre-discharge transport distance setting step in which the control unit sets the pre-discharge transport distance by comparing the printing condition with the table when performing printing.

According to this configuration, since the control unit compares the printing conditions with the table by the first pre-ejection transport distance setting step and the second pre-ejection transport distance setting step based on the attribute information and sets the optimum pre-ejection transport distance by inputting the attribute information of the base material by the user, it is possible to prevent the quality of the printed image from being degraded and to improve the convenience of the printing apparatus.

Description of the symbols

1 … printer as printing device; 2 … unwinding part; 3 … processing part; 4 … coiled part; 20 … unwinding the reel; 21 … a corona processor as a pretreatment section; 22. 34, 41 … tension rollers; 24 … delivery shaft; 30 … impression cylinder; 31 … front drive roller; 31n … nip rollers; 32 … rear drive roller; 40 … take-up reel; 51. 52 … as a print head of the printing section; 61. 62, 63 … UV illuminator; 100 … control section; 101 … storage part; 200 … user interface; e30 … drum encoder; m20 … unreeling motor; m31 … front drive motor; m32 … rear drive motor; m40 … rolling motor; q … conveyance direction; r … conveyance path; s … a base material; s22, S34, S41 … tension sensor; ta1, Tb1, Tc1 … printing tension.