阅读说明：本技术 图像形成装置 (Image forming apparatus with a toner supply device ) 是由 远藤大树 于 2020-03-04 设计创作，主要内容包括：本发明提供一种图像形成装置,其中,该图像形成装置具备：输送带,其输送纸张；压印平板,其将输送带支承为能够滑动；头保持部,其将相对于在输送带上输送的纸张喷出墨的喷墨头排列并保持在与输送带的输送方向正交的方向上；以及一对间隙调整部,该一对间隙调整部的一侧的端部安装于头保持部的下表面的两端,该一对间隙调整部的另一侧的端部安装于压印平板上表面,以便调整头保持部的下表面与压印平板上表面之间的间隙。(The invention provides an image forming apparatus, wherein the image forming apparatus comprises: a conveyor belt that conveys paper; an impression plate that supports the conveyor belt to be slidable; a head holding section that aligns and holds inkjet heads that eject ink with respect to a sheet conveyed on a conveyor belt in a direction orthogonal to a conveying direction of the conveyor belt; and a pair of gap adjusting parts, one end parts of which are mounted at both ends of the lower surface of the head holding part, and the other end parts of which are mounted at the upper surface of the platen so as to adjust the gap between the lower surface of the head holding part and the upper surface of the platen.)

1. An image forming apparatus is characterized in that,

the image forming apparatus includes:

a conveyor belt that conveys paper;

a conveyor belt supporting portion that slidably supports the conveyor belt;

a plurality of head holding portions that align and hold inkjet heads that eject ink with respect to a sheet conveyed on the conveyor belt in a direction orthogonal to a conveying direction of the conveyor belt; and

and a gap adjusting part having one end portion attached to the plurality of head holding parts and the other end portion attached to the conveyor belt supporting part so as to adjust a gap between the plurality of head holding parts and the conveyor belt supporting part.

2. The image forming apparatus according to claim 1,

the gap adjusting section determines the gap according to a resolution of the inkjet head.

3. The image forming apparatus according to claim 1,

the gap adjusting section determines the gap based on ink characteristics of ink ejected from the inkjet head.

4. The image forming apparatus according to claim 2,

the gap adjusting section determines the gap based on ink characteristics of ink ejected from the inkjet head.

Technical Field

The present invention relates to an image forming apparatus that appropriately conveys a sheet to be conveyed and reduces ink contamination.

Background

As an example of an image forming apparatus of an ink jet system, there is an image recording apparatus provided with a head unit in which a line-type recording head is disposed in a direction orthogonal to a conveying direction of a sheet conveyed by a conveyor belt.

Here, when the paper is conveyed at a predetermined conveying speed while being sucked onto the conveyor belt, an air flow is generated along the conveying direction of the paper. At this time, fine droplets (mist) generated by ink ejection and not used for image formation flow by the air flow. The flowing mist drops on a position deviated from the ejection position in the transport path, for example, and ink inside the printer is accumulated as a stain, and the accumulated ink may be transferred to a sheet to deteriorate the image quality.

The smaller the gap between the platen (japanese: プラテン) and the head unit, the more difficult the mist is to flow, and therefore, the ink contamination inside the machine can be reduced.

On the other hand, the smaller the gap between the platen and the head unit, the higher the possibility that the conveyed sheet collides with the head unit.

Therefore, it is necessary to appropriately set the amount of gap between the platen and the head unit.

Patent document 1 (japanese patent application laid-open No. 2009-285952) discloses a technique relating to an image recording apparatus that adjusts the amount of gap between the platen and the head unit.

The head unit is provided with a gap adjustment mechanism for adjusting the gap between the platen and the head unit. The gap adjustment mechanism is provided in the vicinity of 4 vertexes on the lower surface of the head holding portion that holds the head groups of CMYK. The platen is movable relative to the head unit to a recording position where image recording is possible and a standby position separated from the recording position. When adjusting the gap amount between the platen and the head unit, the gap amount is made variable by reciprocating the platen in the direction in which the gap adjustment mechanism is vertically provided.

Disclosure of Invention

Problems to be solved by the invention

Here, the imprint plate is manufactured using a flat plate-shaped member, but there are cases where an error occurs in the flatness of the plate, and the gap between the imprint plate and the head unit differs depending on the position on the imprint plate. If the flatness accuracy of the flat plate is to be improved, a considerable manufacturing cost is incurred.

As described above, in the image recording apparatus described in patent document 1, the gap adjustment mechanism is provided in the vicinity of 4 vertexes of the lower surface of the head holding unit that holds the entire head groups of CMYK. Therefore, if an error occurs in the flatness of the platen, the gap between the inkjet heads fixed at the same height and the platen differs for each inkjet head. Thereby, the possibility of ink contamination in the machine or collision of the conveyed recording medium with the head unit becomes high.

The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus that appropriately conveys a sheet to be conveyed and reduces ink contamination.

Means for solving the problems

In order to achieve the above object, the present invention provides an image forming apparatus, comprising: a conveyor belt that conveys paper; a conveyor belt supporting portion that slidably supports the conveyor belt; a plurality of head holding portions that align and hold inkjet heads that eject ink with respect to a sheet conveyed on a conveyor belt in a direction orthogonal to a conveying direction of the conveyor belt; and a gap adjusting part, one end part of the gap adjusting part is arranged on the plurality of head holding parts, and the other end part of the gap adjusting part is arranged on the conveying belt supporting part so as to adjust the gap between the plurality of head holding parts and the conveying belt supporting part.

ADVANTAGEOUS EFFECTS OF INVENTION

The image forming apparatus of the present invention can prevent the top end of the paper from being contaminated.

Drawings

Fig. 1 is a schematic configuration diagram of an inkjet printing apparatus according to an embodiment of the present invention.

Fig. 2 is a perspective view of a head holding unit, a conveyor belt, and a platen provided in the inkjet printing apparatus according to the embodiment of the present invention.

Fig. 3 is a plan view of the head holding unit, the conveyor belt, and the platen included in the inkjet printing apparatus according to the embodiment of the present invention.

Fig. 4 is a side view schematically showing a state of the head holding unit, the conveying belt, and the platen provided in the inkjet printing apparatus according to the embodiment of the present invention at the time of paper conveyance.

Description of the reference numerals

1. An inkjet printing device; 2. a paper feeding section; 3. a suction conveying section; 4. a printing section; 6. a paper discharge section; 11. a paper feeding table; 12. a paper feed roller; 13. a calibration roller; 21. a conveyor belt; 22. a drive roller; 23-25, a driven roller; 26. a belt drive motor; 27. an impression plate (conveyor belt support); 28. a suction fan; 29. a paper floating sensor; 31(31K, 31C, 31M, 31Y) inkjet head; a 32(32K, 32C, 32M, 32Y) head holding portion; 33(33K, 33C, 33M, 33Y) head gap adjusting part; 33K1a, 33K1b, end.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals. However, the drawings are schematic, and it should be noted that the components are different from the real ones. The drawings also include portions having different dimensional relationships and ratios from each other.

The embodiments described below are illustrative of devices for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the following arrangements of the respective components. The technical idea of the present invention can be variously modified in the claims.

Hereinafter, an embodiment of an inkjet printing apparatus to which the image forming apparatus of the present invention is applied will be described in detail with reference to the drawings.

Fig. 1 is a schematic configuration diagram of an inkjet printing apparatus according to an embodiment of the present invention, fig. 2 is a perspective view of a head holding portion, a conveyor belt, and a platen of the inkjet printing apparatus shown in fig. 1, and fig. 3 is a plan view of the head holding portion, the conveyor belt, and the platen of the inkjet printing apparatus shown in fig. 1. Fig. 4 is a side view schematically showing a state of the head holding section, the conveying belt, and the platen of the inkjet printing apparatus shown in fig. 1 when the sheet is conveyed.

In the following description, as shown in fig. 1, the left-right direction is referred to as the X1-X2 direction and the up-down direction is referred to as the Z1-Z2 direction from the user's perspective. The front direction of the sheet of fig. 1 where the user is located is referred to as the Y1 direction, and the back direction of the sheet is referred to as the Y2 direction. A path indicated by a broken line in fig. 1 is a conveyance path R that conveys a sheet PA as a printing medium. The upstream and downstream in the following description refer to upstream and downstream of the conveyance path R.

As shown in fig. 1 to 3, the inkjet printing apparatus 1 includes a paper feed unit 2, a suction conveyance unit 3, a printing unit 4, and a paper discharge unit 6.

The paper feed unit 2 feeds paper PA as a print medium. The paper feeding unit 2 includes a paper feeding table 11, a paper feeding roller 12, and a registration roller 13.

The paper feeding deck 11 is loaded with paper PA for printing.

The paper feed roller 12 picks up the sheets PA loaded on the paper feed deck 11 one by one and conveys the sheet PA toward the registration roller 13. The paper feed roller 12 is disposed above the paper feed table 11. The paper feed roller 12 is driven to rotate by a motor not shown.

The resist roller 13 temporarily stops the sheet PA conveyed by the sheet feed roller 12, and then conveys the sheet PA toward the suction conveying unit 3. The registration roller 13 is disposed downstream of the paper feed roller 12. The resist roller 13 is driven to rotate by a motor not shown.

The suction transport unit 3 transports the paper PA transported from the registration roller 13 to the printing unit 4 and the paper discharge unit 6. The suction conveying section 3 includes a conveying belt 21, a driving roller 22, driven rollers 23 to 25, a belt driving motor 26, a platen 27, a suction fan 28, and a sheet floating sensor 29.

The conveyor belt 21 is an endless belt that is hung on a drive roller 22 and driven rollers 23 to 25. The conveyor belt 21 is formed with many air intake holes (not shown) as through holes for sucking and holding the paper PA. With the conveying belt 21, the paper PA is held by suction on the upper surface of the conveying belt 21 by the action of negative pressure (suction force) generated at the intake holes by the driving of the suction fan 28.

By the rotational drive of the drive roller 22, the conveying belt 21 is rotated in the clockwise direction in fig. 1. Thereby, the conveyor belt 21 endlessly moves to convey the paper PA sucked and held on the upper surface in the X1 direction.

The driving roller 22 and the driven rollers 23 to 25 are rollers on which the conveyor belt 21 is hung. The drive roller 22 is driven to rotate by a belt drive motor 26, and rotates the conveyor belt 21. The driven rollers 23 to 25 are driven from the driving roller 22 via the conveyor belt 21. The driven roller 23 is disposed at substantially the same height as the drive roller 22, and is spaced apart from the drive roller 22 by a predetermined interval in the X1-X2 direction. The driven rollers 24 and 25 are disposed below the drive roller 22 and the driven roller 23 at substantially the same height and at a predetermined interval in the X1-X2 direction.

The belt driving motor 26 rotationally drives the driving roller 22.

The platen 27 is partially disposed below the conveyor belt 21 between the drive roller 22 and the driven roller 23, and slidably supports the lower surface of the conveyor belt 21. The platen 27 has a plurality of suction holes (not shown) penetrating the platen 27 from the upper surface toward the lower surface at a portion through which the air intake hole of the conveyor belt 21 passes. Further, the platen 27 is provided with a plurality of stiffeners (not shown) in the Y1-Y2 directions.

The suction fan 28 is disposed below the platen 27, and generates an air flow in a downward direction (Z2 direction). Thus, the suction fan 28 sucks air through the suction holes of the platen 27 and the air intake holes of the conveyor belt 21 to generate a negative pressure, and adsorbs the sheet PA to the conveyor belt 21.

The paper floating sensor 29 is provided upstream of the inkjet head 31 and downstream of the registration rollers 13, and detects the floating of the paper PA conveyed by the suction conveying unit 3.

The printing unit 4 prints on the paper PA conveyed by the suction conveying unit 3. The printing section 4 is provided above the suction conveyance section 3. The printing unit 4 is fixed in a housing (not shown) of the inkjet printing apparatus 1. The printing unit 4 includes ink jet heads 31K, 31C, 31M, and 31Y (hereinafter, simply referred to as ink jet heads 31) for black (K), cyan (C), magenta (M), and yellow (Y), a plurality of head holding units 32K, 32C, 32M, and 32Y (hereinafter, simply referred to as head holding units 32) for holding the respective ink jet heads, and a plurality of head gap adjusting units 33K, 33C, 33M, and 33Y (hereinafter, simply referred to as head gap adjusting units 33).

As shown in fig. 3, the inkjet heads 31 are arranged in two lines in a staggered grid pattern in the Y1-Y2 direction without a gap with respect to the sheet PA conveyed in the X1 direction by the suction conveying section 3.

The head holding portion 32K holds the inkjet head 31K above the suction conveying portion 3. The head holding portion 32K is formed in a hollow substantially rectangular parallelepiped shape. The head holding portions 32C, 32M, and 32Y also have the same configuration as the head holding portion 32K.

The head gap adjuster 33K is a member that adjusts a gap, which is a distance between the lower surface of the head holder 32K and the upper surface of the platen 27. As shown in fig. 3, the head gap adjusting section 33K includes a head gap adjusting section 33K1 provided on the lower surface of the head holding section 32K on the Y1 side and a head gap adjusting section 33K2 provided on the lower surface of the head holding section 32K on the Y2 side. That is, the pair of head gap adjusting portions 33K1 and the pair of head gap adjusting portions 33K2 constitute a pair of head holding portions 32K.

As shown in fig. 4, one end portion 33K1a of the head gap adjuster 33K1 is attached to the lower surface of the head holding portion 32K, and the other end portion 33K1b of the head gap adjuster 33K1 is attached to the upper surface of the platen 27. The head gap adjusting portions 33K2 are also attached in the same manner as the head gap adjusting portions 33K 1.

The head gap adjusting section 33K (33K1, 33K2) has a mechanism capable of adjusting the length in the vertical direction (Z1-Z2 direction), and can adjust the length in accordance with the resolution of the inkjet head 31K, the ink characteristics of the ink ejected from the inkjet head 31K, and the like.

The head gap adjusting portions 33C, 33M, and 33Y also have the same configuration as the head gap adjusting portion 33K. That is, since the head gap adjusting portions 33K, 33C, 33M, and 33Y are provided for the head holding portions 32K, 32C, 32M, and 32Y, respectively, the gap, which is the distance between the lower surface of the head holding portion 32 and the upper surface of the platen 27, can be adjusted for the head holding portions 32K, 32C, 32M, and 32Y.

As described above, in the inkjet printing apparatus 1 according to the embodiment of the present invention, one end portion of each head gap adjusting portion 33 is attached to both ends of the lower surface of the head holding portion 32, and the other end portion of each head gap adjusting portion 33 is attached to the upper surface of the platen 27, so that the gap between the lower surface of the head holding portion 32 and the upper surface of the platen 27 can be adjusted.

Therefore, the head gap adjusting unit 33 can adjust the gap, which is the distance between the lower surface of the head holding unit 32 and the upper surface of the platen 27, for each of the head holding units 32K, 32C, 32M, and 32Y. Thus, as shown in fig. 4, even when an error occurs in the flatness of the platen 27 and the platen 27 deforms so as to undulate in the vertical direction (the Z1-Z2 direction), the position of the head holding portion 32 in the vertical direction (the Z1-Z2 direction) can be made to follow the deformation of the platen 27, and the gap can be always uniformly maintained.

This makes it possible to appropriately convey the paper PA without causing the conveyed paper PA to collide with the inkjet head 31, and to reduce ink contamination in the printer due to fogging, thereby reducing degradation in image quality.

As described above, the head gap adjusting unit 33 has a mechanism capable of adjusting the length in the vertical direction (Z1-Z2 direction), and can adjust the length in accordance with the resolution of the inkjet head 31.

As the resolution of the inkjet head 31 is higher, the number of nozzles that eject ink is larger, and thus the amount of mist droplets generated when the paper PA is conveyed tends to be larger. Accordingly, the length of the head gap adjusting section 33 can be adjusted so that the gap becomes smaller as the resolution of the inkjet head 31 becomes higher.

Accordingly, since an appropriate gap can be set for each head holding portion 32 according to the resolution of the inkjet head 31, the paper PA can be further appropriately conveyed without colliding the conveyed paper PA with the inkjet head 31, and the ink contamination in the printer due to the mist can be reduced to reduce the deterioration of the image quality.

The head gap adjusting section 33 can adjust the length in accordance with the ink characteristics of the ink ejected from the inkjet head 31. Ink characteristics include viscosity, ease of color conspicuity, and the like.

If the viscosity of the ink is high, the applied voltage when the ink is ejected from the inkjet head 31 needs to be increased. When the applied voltage is increased, the amount of mist droplets generated when ink is ejected increases accordingly. Accordingly, for example, the length of the head gap adjusting section 33 can be adjusted so that the gap is reduced as the viscosity of the ink ejected from the inkjet head 31 is higher.

Further, the ease of visibility of the ink differs depending on the color. For example, yellow (Y) is less noticeable, but black (K) is more noticeable. Accordingly, for example, the length of the head gap adjusting section 33 can be adjusted so that the color of the ink ejected from the ink ejection head 31 becomes more conspicuous and the amount of mist droplets is reduced by reducing the gap.

Accordingly, since an appropriate gap can be set for each head holding portion 32 according to the ink characteristics, the paper PA can be further appropriately conveyed without colliding the conveyed paper PA with the inkjet head 31, and the ink contamination in the apparatus due to the mist can be reduced to reduce the deterioration of the image quality.

In the embodiment of the present invention, the inkjet printing apparatus 1 has been described as an example, the inkjet heads 31C, 31K, 31M, and 31Y are arranged in two rows in a staggered grid pattern in the Y1 to Y2 direction for each ink color, and the inkjet printing apparatus 1 includes the head holding portions 32C, 32K, 32M, and 32Y that hold the inkjet heads corresponding to the respective ink colors, but the present invention is not limited thereto.

For example, a head holding unit may be provided for holding, for each line, ink jet heads arranged in two lines in a staggered grid pattern in the Y1-Y2 direction. In this case, the head gap adjusting unit is provided for each head holding unit.

< others >

The present invention is not limited to the above-described embodiments, and can be embodied by changing the constituent elements in the implementation stage within the scope not exceeding the gist thereof. In addition, various inventions can be formed by appropriate combinations of a plurality of constituent elements disclosed in the above embodiments. For example, some of the components may be deleted from all the components shown in the embodiments.

The application claims that the entire contents of the application is incorporated into the specification by reference based on the priority of the Japanese special application No. 2019-058708, which was filed on 26/3/2019.