阅读说明：本技术 印刷装置及印刷方法 (Printing apparatus and printing method ) 是由 大原瑛一 于 2021-06-28 设计创作，主要内容包括：本发明涉及印刷装置及印刷方法。提供用于适当地进行读取、读取后的检查的合适的测试图案。印刷装置具备印刷头和控制部,所述印刷头具有喷出作为油墨的点的第一尺寸的点和小于所述第一尺寸的第二尺寸的点的喷嘴,所述控制部通过控制所述印刷头,使用于检查所述喷嘴的油墨喷出的状态的测试图案印刷于印刷介质,所述测试图案具有由所述第一尺寸的多个点形成的第一图案要素和由所述第二尺寸的多个点形成的第二图案要素,所述控制部使所述印刷头印刷所述测试图案,在所述测试图案中,形成所述第二图案要素的所述第二尺寸的点数比形成所述第一图案要素的所述第一尺寸的点数多。(The present invention relates to a printing apparatus and a printing method. A test pattern suitable for reading and inspection after reading is provided. The printing apparatus includes a print head having a nozzle for ejecting a dot of a first size as an ink dot and a dot of a second size smaller than the first size, and a control unit for controlling the print head to print a test pattern for checking a state of ink ejection from the nozzle on a print medium, the test pattern having a first pattern element formed of the dot of the first size and a second pattern element formed of the dot of the second size, and causing the print head to print the test pattern, wherein the number of dots of the second size forming the second pattern element in the test pattern is larger than the number of dots of the first size forming the first pattern element.)

1. A printing apparatus is characterized by comprising a printing head and a control part,

the print head has nozzles that eject dots of a first size as dots of ink and dots of a second size smaller than the first size,

the control unit controls the print head to print a test pattern for inspecting the ink ejection state of the nozzles on a print medium,

the test pattern having a first pattern element formed by a plurality of dots of the first size and a second pattern element formed by a plurality of dots of the second size,

the control unit causes the print head to print the test pattern in which the number of dots of the second size forming the second pattern element is larger than the number of dots of the first size forming the first pattern element.

2. Printing device according to claim 1,

the print head is capable of performing scanning for ejecting ink from the nozzles as the print head moves in a predetermined direction,

the control unit causes the print head to print the test pattern such that the number of times of scanning for printing the second pattern element is larger than the number of times of scanning for printing the first pattern element.

3. Printing device according to claim 1 or 2,

the control unit causes the print head to print the test pattern such that an ejection rate at which the nozzles eject the dots of the second size for printing the second pattern element is higher than an ejection rate at which the nozzles eject the dots of the first size for printing the first pattern element.

4. Printing device according to claim 1,

the control unit makes the speed of the relative movement when the test pattern is printed by the relative movement of the print head and the print medium the same as the speed of the relative movement when the normal printing is performed.

5. Printing device according to claim 1,

the control unit makes a waveform of a drive signal for driving the nozzle when the test pattern is printed be identical to a waveform of a drive signal for driving the nozzle when the test pattern is normally printed.

6. A printing method is characterized by comprising a printing process,

in the printing step, a test pattern is printed on a print medium using a print head having nozzles for ejecting dots of a first size as dots of ink and dots of a second size smaller than the first size, the test pattern being used for checking a state of ink ejection from the nozzles,

the test pattern having a first pattern element formed by a plurality of dots of the first size and a second pattern element formed by a plurality of dots of the second size,

in the printing step, the print head is caused to print the test pattern in which the number of dots of the second size forming the second pattern element is larger than the number of dots of the first size forming the first pattern element.

Technical Field

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

Background

A technique is disclosed as follows: an inkjet printing apparatus records a test pattern on a printing sheet by a recording head, reads the test pattern by a scanner, interpolates read data, and determines an abnormality of a nozzle based on the read data after the interpolation (see patent document 1).

Patent document 1: japanese patent laid-open publication No. 2007-54970

However, when a test pattern is printed on a print medium by a head capable of ejecting dots of a plurality of sizes from nozzles, a density difference between a portion of the test pattern printed by relatively small dots of the plurality of sizes and the print medium may be small. As a result, some of the test pattern reading and inspection based on the read data necessary for the nozzle inspection may not be performed properly. Therefore, an appropriate test pattern is required to properly complete reading and inspection after reading.

Disclosure of Invention

The printing apparatus includes a print head having a nozzle for ejecting a dot of a first size as an ink dot and a dot of a second size smaller than the first size, and a control unit for controlling the print head to print a test pattern for checking a state of ink ejection from the nozzle on a print medium, the test pattern having a first pattern element formed of the dot of the first size and a second pattern element formed of the dot of the second size, and causing the print head to print the test pattern, wherein the number of dots of the second size forming the second pattern element in the test pattern is larger than the number of dots of the first size forming the first pattern element.

The printing method includes a printing step of printing a test pattern on a printing medium using a print head having a nozzle for ejecting a dot of a first size as an ink dot and a dot of a second size smaller than the first size, the test pattern being used to check a state of ink ejection from the nozzle, the test pattern having a first pattern element formed of the dot of the first size and a second pattern element formed of the dot of the second size, and the printing step of printing the test pattern on the print head, wherein the number of dots of the second size forming the second pattern element is larger than the number of dots of the first size forming the first pattern element in the test pattern.

Drawings

Fig. 1 is a block diagram simply showing the configuration of the apparatus.

Fig. 2 is a diagram showing a specific example of a configuration including a conveying unit and a printing head.

Fig. 3 is a diagram showing the relationship between the print medium and the print head from a viewpoint viewed from above.

Fig. 4 is a flowchart showing a flow from printing of the TP to inspection of the nozzles.

Fig. 5 is a diagram illustrating an example of TP image data.

Fig. 6 is a diagram showing a part of TP enlarged.

Fig. 7 is a diagram showing an example of a different-size point number table.

Description of the reference numerals

10 … printing device; 11 … a control unit; 11a … CPU; 11b … ROM; 11c … RAM; 12 … procedure; 12a … print control section; 12b … reading control part; 12c … inspection section; 16 … conveying part; 17 … a carriage; 18 … print head; 19 … reading part; a 21 … nozzle; 26. 26C, 26LC, 26M, 26LM, 26Y, 26K … nozzle columns; 30 … print media; 40 … TP image data; 41. 41CL, 41CS, 41ML, 41MS, 41YL, 41YS, 41KL, 41KS … TP; 42CL, 42CS … pattern elements; 50: different size point tables.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. Note that each of the drawings is only an example for explaining the present embodiment. Since the drawings are examples, there are cases where the ratio and the shape are incorrect or do not match each other, or a part is omitted.

1. The device comprises:

fig. 1 simply shows the configuration of a printing apparatus 10 according to the present embodiment.

The printing apparatus 10 includes a control unit 11, a display unit 13, an operation receiving unit 14, a communication IF15, a conveying unit 16, a carriage 17, a print head 18, a reading unit 19, and the like. IF is an abbreviation for interface. The control unit 11 includes one or more ICs including a CPU11a, a ROM11b, a RAM11c, and the like as processors, other nonvolatile memories, and the like.

In the control unit 11, the CPU11a serving as a processor executes arithmetic processing based on one or more programs 12 stored in the ROM11b, another memory, or the like, using the RAM11c or the like as a work area, thereby realizing various functions of the print control unit 12a, the read control unit 12b, the inspection unit 12c, and the like. Note that the processor is not limited to one CPU, and may be configured to perform processing by a plurality of hardware circuits such as CPUs and ASICs, or may be configured to perform processing by cooperating CPU and hardware circuits.

The display unit 13 is a unit for displaying visual information, and is configured by, for example, a liquid crystal display, an organic EL display, or the like. The display unit 13 may include a display and a driving circuit for driving the display. The operation receiving unit 14 is a means for receiving an operation by a user, and is implemented by, for example, a physical button, a touch panel, a mouse, a keyboard, or the like. Of course, the touch panel may be implemented as one function of the display unit 13.

The display unit 13 and the operation receiving unit 14 may be a part of the configuration of the printing apparatus 10, but may be peripheral devices externally provided to the printing apparatus 10. Communication IF15 is a generic term for one or more IFs used by printing device 10 to connect with the outside in a wired or wireless manner according to a prescribed communication protocol including a well-known communication standard.

The conveying unit 16 is a unit for conveying the printing medium, and includes a roller, a motor for rotating the roller, and the like. The print head 18 performs printing by ejecting ink from nozzles to a print medium in an inkjet manner. The reading unit 19 is a unit that reads a print result on the print medium. The reading section 19 is also referred to as a scanner. However, the printing apparatus 10 may be configured not to include the reading unit 19.

The carriage 17 is a mechanism capable of reciprocating in a predetermined direction by receiving power of a carriage motor, not shown. The predetermined direction in which the carriage 17 moves is also referred to as a main scanning direction. As shown in fig. 2 and 3, the carriage 17 is mounted with a print head 18.

The configuration of the printing apparatus 10 shown in fig. 1 may be realized by one printer or may be realized by a plurality of apparatuses connected to each other so as to be able to communicate with each other.

That is, the printing apparatus 10 may be the printing system 10 as an actual form. The printing system 10 includes, for example, an information processing device functioning as the control unit 11, and a printer including a conveyance unit 16, a carriage 17, a print head 18, and a reading unit 19. The printing apparatus 10 or the printing system 10 realizes the printing method according to the present embodiment.

In addition, the control unit 11 may be a separate information processing device in which a portion functioning as the print control unit 12a and a portion functioning as the read control unit 12b and the inspection unit 12c are provided.

Fig. 2 shows a specific example of a configuration of a part of the printing apparatus 10, which mainly includes the conveyance unit 16 and the printing head 18. Fig. 2 shows the specific example based on a viewpoint perpendicular to the conveyance direction D2 of the print medium 30.

The conveying unit 16 includes a feed shaft 22 on the upstream side of the conveyance, and a take-up shaft 25 on the downstream side of the conveyance. The upstream and downstream of the conveyance are only expressed as upstream and downstream. The long printing medium 30 wound in a roll shape around the feed shaft 22 and the winding shaft 25 is stretched in the conveyance direction D2. Print medium 30 is transported in transport direction D2. The print medium 30 may be paper or a medium made of a material other than paper.

In the example of fig. 2, the print medium 30 wound around the feed shaft 22 is fed downstream by the clockwise rotation of the feed shaft 22. A front drive roller 23 is provided downstream of the feed shaft 22, and a rear drive roller 24 is provided upstream of the take-up shaft 25. The clockwise rotation of the front drive roller 23 conveys the print medium 30 fed from the feed shaft 22 downstream. A pinch roller 23n is provided to the front drive roller 23. The pinch roller 23n abuts against the print medium 30, and the print medium 30 is pinched between the pinch roller 23n and the front drive roller 23.

The clockwise rotation of the rear drive roller 24 causes the print medium 30 conveyed downstream by the front drive roller 23 to be conveyed further downstream. A pinch roller 24n is provided with respect to the rear driving roller 24. The pinch roller 24n abuts against the print medium 30, and the print medium 30 is pinched between the pinch roller 24n and the rear drive roller 24.

Between the front driving roller 23 and the rear driving roller 24, a printing head 18 that ejects ink from above to the printing medium 30 is disposed. As can be seen from fig. 2, the print head 18 is mounted on the carriage 17. The print head 18 can eject inks of a plurality of colors, for example, cyan (C), magenta (M), yellow (Y), black (K), Light Cyan (LC), and Light Magenta (LM).

Each nozzle of the print head 18 opens on a nozzle surface 20 of the print head 18 facing the print medium 30, and the print head 18 ejects ink from the nozzle or does not eject ink based on print data. The ink ejected from the nozzles is referred to as ink droplets, or dots. The print head 18 may also be referred to as a print head, an inkjet head, a liquid ejection head, a recording head, or the like.

The clockwise rotation is performed by the winding shaft 25, and the printed printing medium 30 conveyed by the rear driving roller 24 is wound around the winding shaft 25.

The feed shaft 22, the take-up shaft 25, the rollers, a motor not shown for appropriately rotating these, and the like are specific examples of the conveying section 16 that conveys the printing medium 30. The number and arrangement of rollers provided in the middle of the conveyance path to convey the print medium 30 are not limited to those shown in fig. 2. The color of the ink discharged from the print head 18 is not limited to the above color. Needless to say, a flat platen or the like that supports the printing medium 30 from below to receive ink discharge from the printing head 18 may be provided between the front driving roller 23 and the rear driving roller 24. Further, the portion of the printing medium 30 on which the printing by the printing head 18 is performed may be cut and separated from the printing medium 30 on the upstream side of the portion by a cutter not shown, and collected, instead of being wound in a roll shape by the winding shaft 25.

In the example of fig. 2, the reading unit 19 is provided downstream of the carriage 17 and the print head 18 and upstream of the rear drive roller 24. The reading unit 19 optically reads the printing medium 30 printed by the printing head 18 by the image sensor, and outputs image data as a reading result. The reading unit 19 may be configured to read the print medium 30 while moving with the carriage as in the print head 18, or may be configured to read the print medium in a stationary state.

Fig. 3 simply shows the relationship between the print medium 30 and the print head 18 from a viewpoint of viewing from above. The print head 18 mounted on the carriage 17 moves from one end to the other end in the main scanning direction D1 (forward movement) and from the other end to the one end (backward movement) together with the carriage 17. The main scanning direction D1 intersects the conveying direction D2. The crossing may also be understood as orthogonal. Accordingly, fig. 2 shows the print head 18 and the like based on a viewpoint directed to the main scanning direction D1. However, due to various errors in a printer as a product, for example, the main scanning direction D1 and the conveying direction D2 may not be strictly orthogonal to each other.

Fig. 3 shows an example of the arrangement of the nozzles 21 on the nozzle surface 20. The small circle of one of the nozzle faces 20 is a nozzle 21. The print head 18 includes a plurality of nozzle rows 26 in a configuration in which ink of each color is supplied from a liquid holding unit, not shown, called an ink cartridge, an ink tank, or the like, and is discharged from the nozzles 21. Fig. 3 shows an example of the print head 18 which ejects CMYK inks. The nozzle array 26 formed by the nozzles 21 for ejecting the C ink is also referred to as a nozzle array 26C. Similarly, the nozzle row 26 formed of the nozzles 21 for ejecting the M ink may be referred to as a nozzle row 26M, the nozzle row 26 formed of the nozzles 21 for ejecting the Y ink may be referred to as a nozzle row 26Y, and the nozzle row 26 formed of the nozzles 21 for ejecting the K ink may be referred to as a nozzle row 26K. The nozzle rows 26C, 26M, 26Y, and 26K are arranged along the main scanning direction D1.

Each nozzle row 26 is formed of a plurality of nozzles 21 having a constant or substantially constant nozzle pitch, which is the interval between the nozzles 21 in the conveyance direction D2. The direction in which the plurality of nozzles 21 constituting the nozzle row 26 are arranged is referred to as a nozzle row direction D3. In the example of fig. 3, the nozzle row direction D3 is parallel to the conveyance direction D2. In the configuration in which the nozzle row direction D3 is parallel to the conveyance direction D2, the nozzle row direction D3 is orthogonal to the main scanning direction D1. However, the nozzle row direction D3 may be not parallel to the transport direction D2 but may intersect the main scanning direction D1 obliquely.

Each of the plurality of nozzles 21 is capable of ejecting dots of a plurality of sizes different in volume per one droplet. In the present embodiment, when dots of a certain size are referred to as "first-size" dots, dots of a size smaller than the first size are referred to as "second-size" dots. Hereinafter, for convenience, the dots of the first size are referred to as "large dots", and the dots of the second size are referred to as "small dots". The respective sizes of the large dot and the small dot are the sizes determined in design.

The nozzle rows 26C, 26M, 26Y, and 26K in the conveyance direction D2 are positioned at the same position. The printing apparatus 10 performs the conveyance of the print medium 30 in the conveyance direction D2 and the ink ejection of the print head 18 in accordance with the movement of the carriage 17 in the main scanning direction D1 in combination, thereby printing an image on the print medium 30. The operation in which the print head 18 ejects ink as the carriage 17 moves in the forward path and in the backward path is referred to as "scanning" or "stroke". The movement of the print head 18 in the main scanning direction D1 by the carriage 17 corresponds to one type of relative movement between the print head 18 and the print medium 30.

2. Printing a test pattern:

fig. 4 is a flowchart showing a flow from printing of the TP to inspection of the TP-based nozzles 21, which is executed by the control unit 11 according to the program 12. TP is an abbreviation for test pattern. The flowchart is roughly composed of TP printing processing (step S100), acquisition of a read result of the printed TP (step S200), and inspection based on the read result of the TP (step S300). Step S100 corresponds to a printing step of TP. In fig. 4, step S100 is shown by being subdivided into steps S110 to S150.

In step S110, the print control unit 12a acquires TP image data, which is image data representing a TP, from a storage source such as a predetermined memory or storage device with which the control unit 11 can communicate. The TP image data is, for example, bitmap image data in which a predetermined color system defines the color of each pixel. The color system described here refers to various color systems such as RGB (red, green, blue) color system and CMYK color system.

In step S120, the print control unit 12a sets the printing conditions of TP. The print control unit 12a directly sets the print conditions for normal printing to the print conditions for TP. The normal printing is a process of printing an object such as a photograph, a text, and CG arbitrarily selected by a user, and does not print the TP. The user can set the printing conditions for normal printing by operating the operation receiving unit 14 while visually checking a User Interface (UI) screen displayed on the display unit 13. The printing conditions include, for example, the type of the printing medium 30 and the printing quality.

The print quality is presented to the user by a sensory option such as high definition, normal, and fast, for example, but the print control unit 12a sets items necessary for executing printing, such as the moving speed of the carriage 17, the conveying speed of the conveying unit 16, the waveform of a drive signal for driving the nozzles 21, and the drive cycle of the nozzles 21 in the course, in accordance with the selection of the print quality. Further, initial settings are prepared for the printing conditions, and when the user does not change the initial settings in particular, the printing control unit 12a applies the initial settings to TP printing and normal printing.

The execution sequence of step S110 and step S120 may be reverse to the expression sequence in fig. 4, or may be substantially simultaneous.

In step S130, the print control unit 12a generates print data for printing the TP based on the TP image data. The print control unit 12a performs predetermined image processing such as color conversion processing and halftone processing On the TP image data as necessary, and generates print data in which ink ejection (Dot On) or ink non-ejection (Dot Off) is predetermined for each pixel and for each ink color. The dot as used herein means either a dot or a dot. As shown in the example of fig. 3, assuming that the print head 18 uses inks of four colors of CMYK, the print control section 12a generates print data in which dot presence/absence is defined for each pixel and for each of CMYK based on the TP image data in step S130.

Fig. 5 shows an example of the TP image data 40 acquired in step S110. The TP image data 40 is image data representing TP 41. Fig. 5 and fig. 6 described later also show the correspondence between the TP image data 40 and the directions D1 and D2. TP41 includes the TPs for each ink color. Referring to fig. 5, TP41CL and 41CS represent color TP by C. Similarly, TP41ML, 41MS are TP of M color, TP41YL, 41YS are TP of Y color, and TP41KL, 41KS are TP of K color. TP41CL, 41ML, 41YL, and 41KL are TP printed with large dots of the corresponding color, and TP41CS, 41MS, 41YS, and 41KS are TP printed with small dots of the corresponding color.

In the TP image data 40, TP41CL, 41CS, 41ML, 41MS, 41YL, 41YS, 41KL, 41KS by ink color and by size are arranged correspondingly in the main scanning direction D1, and the positions in the conveying direction D2 are the same as each other. TP41CL, 41CS, 41ML, 41MS, 41YL, 41YS, 41KL, 41KS are each a set of a plurality of "pattern elements". In the example of fig. 5, the individual pattern elements are ruled lines parallel to the main scanning direction D1. One pattern element is an image printed by one nozzle 21 of the corresponding ink color.

Fig. 6 shows an enlarged view of a portion of TP41 represented by TP image data 40. Specifically, fig. 6 shows a part of each of the TPs 41CL and 41 CS. TP41CL is constituted by a plurality of pattern elements 42CL arranged at equal intervals in the conveyance direction D2, and TP41CS is constituted by a plurality of pattern elements 42CS arranged at equal intervals in the conveyance direction D2. In fig. 6, for convenience of understanding, a part of the nozzle row 26C used for printing of TP41CL and 41CS is shown together with TP41CL and 41 CS. That is, the pattern elements 42CL are arranged at the same interval as the nozzle pitch in the conveyance direction D2 so that one pattern element 42CL constituting TP41CL is printed by one nozzle 21 constituting the nozzle row 26C. Similarly, the pattern elements 42CS are arranged at the same interval as the nozzle pitch in the conveying direction D2 so that one pattern element 42CS constituting TP41CS is printed by one nozzle 21 constituting the nozzle row 26C.

In the example of fig. 6, in order to facilitate the confirmation of each pattern element 42CL at the time of inspection, each pattern element 42CL is arranged at a position shifted in the main scanning direction D1 such that the positions in the main scanning direction D1 coincide with each other at three cycles. Similarly, the pattern elements 42CS are also arranged at shifted positions in the main scanning direction D1 such that the positions of the pattern elements 42CS in the main scanning direction D1 coincide with each other at three cycles. However, the positions of the pattern elements constituting the TP corresponding to one combination of the ink color and the dot size in the main scanning direction D1 may all be the same.

In the example of fig. 6, in order to reduce the penetration of each of the pattern element 42CL and the pattern element 42CS, the pattern element 42CL and the pattern element 42CS are arranged so as to be shifted in the dot position in the main scanning direction D1. For example, when the pattern element 42CL is printed in two passes, dots printed in the first pass are arranged at odd-numbered pixel positions in the main scanning direction D1, and dots printed in the second pass are arranged at even-numbered pixel positions in the main scanning direction D1. For example, when the pattern element 42CS is printed in the six passes, dots printed in the first, third, and fifth passes are arranged at odd-numbered pixel positions in the main scanning direction D1, and dots printed in the second, fourth, and sixth passes are arranged at even-numbered pixel positions in the main scanning direction D1. However, when printing is performed on a printing medium that is less likely to cause bleeding, dots may be formed for all pixels by each pass.

The print data generated in step S130 is image data in which the TP41 expressed by the TP image data 40 is expressed by dots/dots. Each of the pattern elements constituting TP41CL, 41CS, 41ML, 41MS, 41YL, 41YS, 41KL, 41KS is formed only by dots of the corresponding ink color and size.

In step S140, the print control unit 12a determines the number of passes and the removal rate for printing the TP for each dot size. As shown in fig. 5, since TP41 is composed of TP41CL, 41CS, 41ML, 41MS, 41YL, 41YS, 41KL, 41KS, the print controller 12a determines the number of strokes and removal rate from the dot size for each of TP41CL, 41CS, 41ML, 41MS, 41YL, 41YS, 41KL, 41 KS.

In the present embodiment, a pattern element formed by a plurality of dots of a first size is referred to as a "first pattern element", and a pattern element formed by a plurality of dots of a second size is referred to as a "second pattern element". Each pattern element 42CL constituting TP41CL shown in fig. 6 is an example of a first pattern element, and each pattern element 42CS constituting TP41CS is an example of a second pattern element.

Fig. 7 shows an example of the different-size point number table 50. The dot table 50 of different sizes is stored in advance in a memory or a storage device inside or outside the printing apparatus 10 accessible to the control unit 11. The different-size dot table 50 is a table defining parameters for directly or indirectly determining the number of dots for printing each dot size TP on the print medium 30. According to fig. 7, the different-size dot number table 50 defines the number of strokes and the removal rate for large dots and small dots, which are dot sizes, respectively. In step S140, the print control unit 12a refers to the different-size dot number table 50 to determine the number of strokes and the removal rate for each dot size.

The number of passes is the number of passes to print the TP. For example, if the number of passes is 2 for a certain dot size, the pass for printing the TP of one color of the dot size represented by the print data generated in step S130 is repeated twice, instead of sharing the TP of one color of the dot size represented by the print data by two passes. Therefore, the larger the number of passes, the more the number of dots forming the TP reproduced on the print medium 30 increases. From the different-size dot count table 50, the print control unit 12a specifies the number of passes as 2 for the large dots and 6 for the small dots.

The removal rate is a removal rate in one pass. For example, if the removal rate is 50% for a certain dot size, ink is forcibly ejected as no dots regardless of whether dots are originally present or absent for 50% of the pixels in one pass during printing of TP for one ink color of the dot size represented by the print data generated in step S130. Therefore, the higher the removal rate, the more the number of dots forming TPs reproduced on the print medium 30 decreases. It can be said that if the removal rate is high, the ejection rate of ink ejected from the nozzles 21 decreases, and if the removal rate is low, the ejection rate of ink ejected from the nozzles 21 increases. Therefore, by changing the removal rate for each dot size, the ejection rate of the nozzle 21 can be controlled for each dot size. From the different-size dot number table 50, the print control unit 12a determines the removal rate to be 50% for large dots and 0% for small dots. The removal rate of 0% means that printing is performed according to the print data corresponding to each pass.

It is assumed here that, in the print data generated in step S130, each of the pattern elements constituting any one of TP41CL, 41CS, 41ML, 41MS, 41YL, 41YS, 41KL, and 41KS is constituted by substantially the same number of dots. According to step ST140 referring to the different-size dot number table 50, the stroke number is determined to be 2 and the removal rate is determined to be 50% for TP41CL, 41ML, 41YL, 41KL which are TP based on large dots, and the stroke number is determined to be 6 and the removal rate is determined to be 0% for TP41CS, 41MS, 41YS, 41KS which are TP based on small dots. Therefore, when the dot numbers of the pattern elements printed on the printing medium 30 are compared in response to the determination in step S140, the dot number of the small dot of the C ink forming one second pattern element, for example, one pattern element 42CS is about 6 times the dot number of the large dot of the C ink forming one first pattern element, for example, one pattern element 42 CL.

In step S150, the print control unit 12a controls the movement of the carriage 17 and the ejection of ink from the print head 18 based on the print conditions set in step S120, the print data generated in step S130, and the number of strokes and removal rate for each dot size determined in step S140, thereby printing TP41 on the print medium 30. Specifically, print head 18 performs six passes to print TP41 to print medium 30 according to the different size dot table 50. The print head 18 ejects dots of CMYK ink from the nozzles 21 of the nozzle rows 26C, 26M, 26Y, and 26K through all six passes of the six passes, and prints TP41CS, 41MS, 41YS, and 41KS at a removal rate of 0% based on the print data. In addition, the print head 18 ejects large dots of CMYK ink from the nozzles 21 of the nozzle rows 26C, 26M, 26Y, and 26K in two passes of the six passes, and prints TP41CL, 41ML, 41YL, and 41KL at a removal rate of 50% based on the print data.

As a result, the print control unit 12a prints TP41 in which the number of dots forming the second size of the second pattern element is larger than the number of dots forming the first size of the first pattern element when comparing the pattern element units. Note that, in step S150, the print control unit 12a does not cause the transport unit 16 to transport the print medium 30 from the start of the first pass to the end of the last pass for the printing head 18 to print the TP 41.

The above is the description of step S100. Steps S200 and S300 will be briefly described.

In step S200, the reading control unit 12b controls the reading unit 19 to read the printing medium 30 after the TP41 is printed in step S100, and acquires image data as a result of the reading from the reading unit 19. Of course, the conveying unit 16 performs conveyance by an amount necessary for the reading unit 19 to read the printed print medium 30.

However, in step S200, the result of reading the print medium 30 on which TP41 is printed may be acquired. Therefore, the user may read the printing medium 30 on which the TP41 is printed by an external scanner, and the printing apparatus 10 may acquire the read result via the communication IF 15.

In step S300, the inspection unit 12c inspects the ink ejection state of the nozzles 21 of the print head 18 based on the image data acquired as the reading result in step S200. The state of ink ejection is divided into normal and abnormal. The abnormality is ejection failure of a dot, deviation of a landing position of a dot from an ideal position, or the like. The inspection unit 12c analyzes the image data and specifies the density and position of each pattern element, thereby inspecting whether the ink of each dot size is normally or abnormally ejected for each nozzle 21 and storing the inspection result as data.

The flowchart of fig. 4 ends above.

3. Summary and description of the effects:

as described above, according to the present embodiment, the printing apparatus 10 includes: a print head 18 having nozzles 21 for ejecting dots of a first size which are dots of ink and dots of a second size smaller than the first size; and a control unit 11 for controlling the print head 18 to print a TP for inspecting the state of the ink discharged from the nozzles 21 on the print medium 30. The TP has a first pattern element formed by a plurality of dots of a first size and a second pattern element formed by a plurality of dots of a second size. The control unit 11 causes the print head 18 to print TP in which the number of dots of the second size forming the second pattern element is larger than the number of dots of the first size forming the first pattern element.

According to the above configuration, the second pattern element of the small dots as the dots of the second size is printed using more dots than the first pattern element of the large dots as the dots of the first size. As a result, the second pattern element can be printed more densely to some extent. Thereby, the following problems can be eliminated: since the difference in luminance from the print medium 30 is small, the reading and the inspection based on the reading result cannot be appropriately performed for the portion of the TP for inspecting each nozzle 21, which is printed with relatively small dots. Specifically, in the case of a pattern element having a small difference in luminance from the white or bright color printing medium 30, it is difficult to accurately specify a position or the like when performing an inspection based on the read result, and therefore, it is not possible to accurately determine whether the pattern element is normal or abnormal as described above, but if the TP printed in step S100 of the present embodiment is used, it is possible to accurately inspect dots of different sizes ejected from the nozzles 21 based on the pattern element.

Further, according to the present embodiment, the print head 18 can perform scanning of discharging the ink from the nozzles 21 in accordance with the movement in the predetermined direction, and the control section 11 causes the print head 18 to print TP by making the number of scanning for printing the second pattern element larger than the number of scanning for printing the first pattern element. That is, the control unit 11 causes the print head 18 to print TP so that the number of times of scanning for printing the second pattern element is larger than the number of times of scanning for printing the first pattern element.

According to the above configuration, the control unit 11 can easily print TP having a larger number of dots of the second size than the number of dots of the first size, which form the second pattern element, by making the number of scanning times for printing the second pattern element larger than the number of scanning times for printing the first pattern element.

Further, according to the present embodiment, the control unit 11 may cause the print head 18 to print TP by causing the nozzle 21 to eject the dots of the second size for printing the second pattern element at an ejection rate higher than that of the nozzle 21 to eject the dots of the first size for printing the first pattern element. That is, the control unit 11 causes the print head 18 to print TP so that the ejection rate at which the nozzles 21 eject the dots of the second size for printing the second pattern element is higher than the ejection rate at which the nozzles 21 eject the dots of the first size for printing the first pattern element.

According to the above configuration, the control unit 11 can easily print TP having a larger number of dots of the second size forming the second pattern elements than the number of dots of the first size forming the first pattern elements by making the ejection rate at which the nozzles 21 eject the dots of the second size for printing the second pattern elements higher than the ejection rate at which the nozzles 21 eject the dots of the first size for printing the first pattern elements.

The number of strokes and the removal rate for each dot size in the different-size point table 50 shown in fig. 7 are merely an example. In addition, the different-size dot count table 50 may be a table in which the number of strokes is set to be the same regardless of the dot size and a difference is provided between the first size and the second size with respect to the removal rate, for example. Alternatively, the different-size dot number table 50 may also be a table in which the removal rate is set to be the same regardless of the dot size and a difference is set between the first size and the second size for the number of strokes.

In addition, according to the present embodiment, the printing conditions when printing TP are the same as those when performing normal printing.

That is, the control unit 11 makes the speed of the relative movement when printing TP by the relative movement of the print head 18 and the print medium 30 the same as the speed of the relative movement when performing normal printing. As described above, the speed of the relative movement described here is the moving speed of the carriage 17 at the time of the stroke execution.

The control unit 11 makes the waveform of the drive signal for driving the nozzles 21 during printing TP the same as the waveform of the drive signal for driving the nozzles 21 during normal printing. The driving signal for driving the nozzles 21 is a pulse wave, and dots are discharged from the nozzles 21 by applying the driving signal to the driving elements of the nozzle 21 units based on dot information. If the waveforms of the drive signals are different, the size of the dot ejected by the nozzle 21 by one drive is also different. Therefore, in the present embodiment, the waveform of the drive signal for ejecting the first dot from the nozzle 21 when printing the TP is the same as the waveform of the drive signal for ejecting the first dot from the nozzle 21 when performing the normal printing, and similarly, the waveform of the drive signal for ejecting the second dot from the nozzle 21 when printing the TP is the same as the waveform of the drive signal for ejecting the second dot from the nozzle 21 when performing the normal printing.

In this way, by sharing the speed of the relative movement and the drive signal between the printing of the TP and the normal printing, the TP suitable for the inspection of the nozzles 21 can be printed under the same conditions as those in the normal printing.

The present embodiment also discloses various inventions such as the printing apparatus 10, the method other than the printing system 10, and the program 12.

The printing method includes a printing step of printing a TP onto a print medium using a print head 18, the print head 18 having a nozzle 21 that ejects a first size of dots as ink dots and a second size of dots smaller than the first size, the TP being used to inspect a state of the ink ejected from the nozzle 21, the TP having a first pattern element formed of a plurality of dots of the first size and a second pattern element formed of a plurality of dots of the second size, and the printing step of printing the TP onto the print head 18, the number of dots of the second size forming the second pattern element being larger than the number of dots of the first size forming the first pattern element.

4. Other embodiments are as follows:

the present embodiment is not limited to the above.

The plurality of nozzles 21 of the print head 18 can eject more than two kinds of dot sizes, respectively. The nozzle 21 may eject a large dot, a middle dot, and a small dot in descending order of the volume of each droplet, for example. In this case, in the present embodiment, the large dots may be treated as the first size and the middle dots and the small dots may be treated as the second size, or the large dots and the middle dots may be treated as the first size and the small dots may be treated as the second size.

The printing apparatus 10 may print TPs such that the smaller the dot size, the larger the number of dots per pattern element, for each of the pattern elements based on the large dots, the pattern elements based on the medium dots, and the pattern elements based on the small dots.

Further, a plurality of "small dots" as the second size dots may be discharged to form "large dots" as the first size dots.

In the present embodiment, the dots of the first size and the dots of the second size are discharged from the same nozzle, but the present invention is not limited thereto, and the print head 18 may include a nozzle for discharging the dots of the first size and a nozzle for discharging the dots of the second size.

The printing apparatus 10 is not limited to the so-called serial type ink jet printer in which the print head 18 is mounted on the carriage 17 that moves in the main scanning direction D1 as described above.

A so-called line inkjet printer may also be assumed as follows: ink ejection is performed by the print head 18 having the nozzle rows 26 extending in the main scanning direction D1 intersecting the conveying direction D2 for each ink color and having a length capable of covering the width of the print medium 30. In the line inkjet printer, the nozzle column direction D3 may be understood as being parallel to the main scanning direction D1 instead of the conveying direction D2.

In the description of the present embodiment, assuming that the printing apparatus 10 is a line inkjet printer, the TP41 shown in fig. 5 prints the pattern elements as ruled lines on the printing medium 30 not in the main scanning direction D1 but in a direction parallel to the conveyance direction D2. Note that the above-described strokes of the print head 18 are realized a plurality of times, and are handled by reverse feeding by the transport unit 16. The reverse feeding is a process in which the conveying section 16 conveys the printing medium 30 from downstream to upstream. That is, printing of the print medium 30 is performed once while the print medium 30 passes under the print head 18 in the process of transporting the print medium 30 from upstream to downstream. Thereafter, the transport unit 16 performs reverse feeding to return the portion of the print medium 30 on which the one-time printing is finished to the upstream position of the print head 18, and starts transporting the portion downstream. By repeating this process, TP41 can be repeatedly printed in the same manner as a serial inkjet printer performs overlapping printing of TP41 by a plurality of passes.

When the printing apparatus 10 is a line inkjet printer, the conveyance of the printing medium 30 by the conveyance unit 16 during the printing period of the printing head 18 corresponds to the relative movement of the printing head 18 and the printing medium 30. That is, when the printing apparatus 10 is a line inkjet printer, the transport speed of the transport unit 16 during the printing period of the print head 18 is shared between the time of printing TP and the time of normal printing.

Needless to say, the printing medium 30 may not be the continuous paper wound in a roll shape as shown in fig. 2. The printing medium 30 may be a single sheet of paper or the like divided in units of pages.