Test pattern, test pattern printing method and printing device

Abstract

To grasp positional deviation of a head.SOLUTION: A test pattern 60 is printed on a medium M by ink discharged from a head 23 and a head 24. The test pattern 60 has a first line 61 and a second line 62 printed so as to be alternately aligned in a Y direction. The first line 61 is formed with ink discharged from a plurality of nozzles N which are aligned in an X direction perpendicular to the Y direction. of the head 23. The second line 62 is formed with ink discharged from the plurality of nozzles N which are aligned in the X direction, of the head 24.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] The present invention relates to a test pattern, a method for printing a test pattern, and a printing device. [Background technology]

[0002] The printing device is equipped with multiple inkjet heads. The inkjet heads have multiple nozzle rows arranged in the main scanning direction. Each nozzle row is made up of multiple nozzles lined up in the sub-scanning direction. The printing device prints on the medium by ejecting ink from each nozzle while moving the medium and the inkjet head relatively in the main scanning direction and the sub-scanning direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-94827 Summary of the Invention [Problem to be solved by the invention]

[0004] If one of the inkjet heads is misaligned among multiple inkjet heads, the dot positions of that inkjet head may be misaligned with the dot positions of the other inkjet heads. The dot positions are the positions where ink ejected from the nozzles of the inkjet head lands on the medium. If the dot positions of multiple inkjet heads do not match, this can affect the quality of printed matter, so there is a need for printing devices to be able to grasp the misalignment of the dot positions of the inkjet heads. [Means for solving the problem]

[0005] The present invention provides (1) A test pattern printed on a medium by ink ejected from a first inkjet head and a second inkjet head, having first and second lines printed alternately in a first direction; the first line is formed by ink ejected from a plurality of nozzles of the first inkjet head arranged in a second direction perpendicular to the first direction, The second line is formed by ink ejected from a plurality of nozzles of the second inkjet head arranged in the second direction. 、 the first line and the second line have an overlapping portion where they overlap when viewed from the first direction, The overlapping portion is visually recognized as a filled area when a landing position of ink ejected from the nozzles of the first inkjet head and a landing position of ink ejected from the nozzles of the second inkjet head coincide with each other in the first direction. .

[0007] ( 2 ) the test pattern includes a first reference line formed by ink ejected from the nozzles of the first inkjet head; a second reference line formed by ink ejected from the nozzles of the second inkjet head; When the landing position of ink ejected from the nozzles of the first inkjet head and the landing position of ink ejected from the nozzles of the second inkjet head coincide in the first direction, the first reference line and the second reference line have an overlapping area.

[0008] ( 3 the test pattern further includes a pattern in which first linear portions located on one side of an imaginary line along the first direction and second linear portions located on the other side are alternately arranged in the first direction, The first linear portion and the second linear portion are formed by overlapping ink ejected from the nozzles of the first inkjet head and ink ejected from the nozzles of the second inkjet head.

[0009] ( 4) the test pattern has a first area on one side of the virtual line that is filled with ink ejected from the nozzles of the first inkjet head, and a second area on the other side of the virtual line that is filled with ink ejected from the nozzles of the second inkjet head; The first linear portion and the second linear portion are formed by opposing ends of the first region and the second region.

[0010] ( 5 ) In the test pattern, if the landing position of the ink ejected from the nozzles of the first inkjet head and the landing position of the ink ejected from the nozzles of the second inkjet head do not match in the second direction, a gap or a high-density area will occur at the boundary between the first area and the second area.

[0011] ( 6 In the test pattern, the first linear portion and the second linear portion are parallel to the virtual line, end portions of the first linear portion and the second linear portion are connected to each other by a third linear portion that is perpendicular to the virtual line; The third linear portion is formed by overlapping the ink ejected from the nozzles of the first inkjet head and the ink ejected from the nozzles of the second inkjet head.

[0012] The present invention provides ( 7 ) A method for printing a test pattern on a medium by ejecting ink from a first inkjet head and a second inkjet head, The first and second lines are printed alternately in a first direction, forming the first line by ejecting ink from a plurality of nozzles of the first inkjet head arranged in a second direction perpendicular to the first direction; The second line is formed by ejecting ink from a plurality of nozzles of the second inkjet head that are aligned in the second direction. death, the first line and the second line have an overlapping portion where they overlap when viewed from the first direction, The overlapping portion is visually recognized as a filled area when a landing position of ink ejected from the nozzles of the first inkjet head and a landing position of ink ejected from the nozzles of the second inkjet head coincide with each other in the first direction..

[0013] The present invention provides ( 8 ) Ink is ejected from the first inkjet head and the second inkjet head to print a test pattern on the medium. printing device And, The first and second lines are printed alternately in a first direction, forming the first line by ejecting ink from a plurality of nozzles of the first inkjet head arranged in a second direction perpendicular to the first direction; The second line is formed by ejecting ink from a plurality of nozzles of the second inkjet head that are aligned in the second direction. death, the first line and the second line have an overlapping portion where they overlap when viewed from the first direction, The overlapping portion is visually recognized as a filled area when a landing position of ink ejected from the nozzles of the first inkjet head and a landing position of ink ejected from the nozzles of the second inkjet head coincide with each other in the first direction. . [Effects of the Invention]

[0014] According to the present invention, it is possible to grasp the deviation of the dot positions of the inkjet head from the test pattern. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a perspective view of the printing device as seen from the front side. [Figure 2] FIG. 1 is a block diagram illustrating a configuration of a printing device. [Figure 3] FIG. 2 is a diagram schematically illustrating the head portion as viewed from the front side. [Figure 4] FIG. 2 is a diagram schematically illustrating the head portion as viewed from above. [Figure 5] FIG. 2 is a diagram schematically illustrating the arrangement of nozzles that constitute a nozzle unit. [Figure 6] FIG. 10 is a diagram showing an example of printing when the dot positions of the heads are aligned. [Figure 7] 10A and 10B are diagrams illustrating an example of printing when the dot positions of the heads do not match. [Figure 8] 10 is a flowchart illustrating an example of a correction procedure. [Figure 9] FIG. 10 is a diagram showing a test pattern for tilt correction. [Figure 10] FIG. 10 is an enlarged view of the area surrounded by the frame A in FIG. 9. [Figure 11] 1A to 1C are diagrams illustrating a method for forming a test pattern. [Figure 12] 10A and 10B are diagrams illustrating changes in the test pattern when the head is tilted. [Figure 13] 10A and 10B are diagrams illustrating changes in the test pattern when the head is tilted. [Figure 14] FIG. 4 is a diagram illustrating the positional relationship of a nozzle portion. [Figure 15] FIG. 10 is a diagram illustrating a case where the head is tilted greatly. [Figure 16] FIG. 10 is a diagram illustrating a case where the tilt of the head is small. [Figure 17] FIG. 10 is a diagram showing a test pattern for correcting misalignment in the Y direction. [Figure 18] 1A and 1B are diagrams illustrating a method for forming a test pattern. [Figure 19] 10A and 10B are diagrams illustrating changes in the test pattern when the head is misaligned in the Y direction. [Figure 20] FIG. 10 is a diagram showing a test pattern for correcting misalignment in the X direction. [Figure 21] FIG. 21 is an enlarged view of the area surrounded by the frame A in FIG. 20. [Figure 22] 10A and 10B are diagrams illustrating changes in the test pattern when the head is misaligned in the X direction. [Figure 23] FIG. 10 is a diagram showing a test pattern when the head is misaligned in the Y direction. [Figure 24] 10A and 10B are diagrams illustrating a method for forming a test pattern according to Modification 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a perspective view of the printing device 1 as seen from the front side. FIG. 2 is a block diagram showing the configuration of the printing device 1. FIG. 3 is a diagram showing a schematic view of the head unit 22 as viewed from the front side. FIG. 4 is a diagram schematically showing the head portion 22 as viewed from above. In the following description, the "Y direction" refers to the main scanning direction of the printing device 1. The main scanning direction is the left-right direction when viewed from the front of the printing device 1. The "X direction" refers to the sub-scanning direction. The sub-scanning direction is a direction perpendicular to the main scanning direction, and is the direction from the front of the printing device 1 toward the back. The "Z direction" refers to the vertical direction when the printing device 1 is placed on a horizontal surface, and is a direction perpendicular to the X and Y directions. Furthermore, the "Y1 side" refers to one side in the Y direction (the left side in Figure 3) when viewed from the front of the printing device 1, and the "Y2 side" refers to the other side (the right side in Figure 3). The "X1 side" refers to the front side of the printing device 1, and the "X2 side" refers to the back side.

[0017] The printing device 1 uses an inkjet method to print on a medium M. The medium M can be, for example, paper, fabric, or resin film. 1, the printing device 1 includes a main body 2 and a stand 3 that supports the main body 2. The main body 2 includes a platen 21 that supports the medium M. The main body 2 also includes a head unit 22 that ejects ultraviolet-curable ink onto the medium M, and an ultraviolet irradiation unit 25 that irradiates the ink ejected onto the medium M with ultraviolet rays. The main body 2 also includes an operation panel 26 that accepts user operation inputs, and a controller 27 that controls the operation of the printing device 1.

[0018] As shown in Figure 2, the printing device 1 includes an ink supply mechanism 28 that supplies ink to the head unit 22, a movement mechanism 29 that moves the head unit 22 and the ultraviolet irradiation unit 25 in the Y direction, and a feed mechanism 30 that feeds the medium M in the X direction.

[0019] As shown in FIG. 3, the ink supply mechanism 28 has an ink bottle 281 that stores ink, and an ink supply path 282 that connects the ink bottle 281 and the head unit 22.

[0020] As shown in FIG. 1, the movement mechanism 29 (see FIG. 2) includes a carriage 291 on which the head unit 22 and the ultraviolet irradiation unit 25 are mounted, and a guide rail 292 that guides the carriage 291. The guide rail 292 is disposed along the Y direction of the main body 2. Although not shown, the movement mechanism 29 includes a belt, a drive pulley and a driven pulley around which the belt is wound, and a motor that rotates the drive pulley. The carriage 291 is fixed to the drive belt. By rotating the drive belt with the motor, the carriage 291 moves along the guide rail 292 in the Y direction of the main body 2.

[0021] Although not shown, the feed mechanism 30 (see FIG. 2) includes a motor, a roller rotated by the motor, and multiple pinch rollers. The medium M is fed in the X direction by rotating the roller while sandwiching the medium M between the roller and the multiple pinch rollers. The medium M is fed from the X2 side to the X1 side. That is, in the feed direction of the medium M, the X2 side is the upstream side and the X1 side is the downstream side.

[0022] The printing device 1 moves the carriage 291 in the Y direction using the movement mechanism 29, and feeds the medium M in the X direction using the feed mechanism 30. This causes the carriage 291 to move relative to the medium M in the X and Y directions. The printing device 1 ejects ultraviolet-curable ink from the head unit 22 onto the medium M while moving the carriage 291. The printing device 1 cures the ink that has landed on the medium M using the ultraviolet irradiation unit 25. In this way, printing on the medium M is performed.

[0023] Operation panel 26 may be, for example, a touch panel. Operation panel 26 displays images output by controller 27 and accepts operational inputs from the user. Operation panel 26 may be configured, for example, with a display that displays images and switches that accept operational inputs.

[0024] The controller 27 controls the operation of each part of the printing device 1. The controller 27 can be, for example, a microcomputer. The controller 27 includes a processor such as a CPU (Central Processing Unit) and memories such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), and RAM (Random Access Memory). The operation of the printing device 1 is performed by the CPU executing a program stored in the memory.

[0025] The controller 27 includes a communication device and receives image data to be printed on the medium M from an external computer or the like. The controller 27 generates print data for controlling each part of the printing device 1 from the input image data. The print data includes dot positions. The dot positions refer to the positions on the medium M where the ink ejected from the head unit 22 lands. The dot positions are indicated, for example, by XY coordinates. The controller 27 converts the position coordinates of each pixel included in the image into dot positions to generate the print data. The controller 27 controls the feed mechanism 30 and the movement mechanism 29 based on the print data to move the head unit 22 to the dot position and eject ink.

[0026] 3, the head unit 22 includes two inkjet heads 23 and 24 (hereinafter simply referred to as "heads 23 and 24"). The heads 23 and 24 are disposed opposite the medium M on the platen 21 (see FIG. 1). 4, the heads 23 and 24 are arranged in a so-called staggered arrangement. The heads 23 and 24 are arranged with their positions shifted in the X and Y directions. The head 24 is arranged on the Y2 side of the head 23 in the Y direction, and on the X1 side of the head 23 in the X direction. The head 24 is arranged downstream of the head 23 in the feed direction of the medium M. When viewed from the Y direction, a portion of the head 24 overlaps with the head 23.

[0027] Head 23 has eight nozzle portions 231 to 238 aligned in the Y direction. Head 24 similarly has eight nozzle portions 241 to 248 aligned in the Y direction. As shown in Fig. 4, end regions 23a and 24a that are not reached by nozzle portions 231 to 238 and 241 to 248 are provided on the X2 side of heads 23 and 24. End region 24a of head 24 overlaps with head 23 when viewed from the Y direction. As shown in FIG. 3, the nozzle portions 231 to 238 and 241 to 248 are provided on the surfaces of the heads 23 and 24 that face the medium M, respectively. The heads 23 and 24 are provided with ink supply ports (not shown) that connect to the ink supply channels 282. Ink is supplied from the ink bottle 281 to the nozzle portions 231 to 238 and 241 to 248 of the heads 23 and 24, respectively, via the ink supply channels 282 and the ink supply ports.

[0028] In the embodiment, as an example, four colors of ink, C (cyan), M (magenta), Y (yellow), and K (key plate), are supplied to the heads 23 and 24. In this example, black is used as the key plate. For ease of understanding, in FIG. 4, the colors of ink supplied to the nozzle portions 231-238 and 241-248 are indicated by the initials C, M, Y, and K.

[0029] 3, the nozzle portions 231 to 238 of the head 23 are provided at a lower portion of the head 23 facing the medium M. Although not shown, the head 23 is provided with piezo elements corresponding to the respective nozzles of the nozzle portions 231 to 238. When the piezo elements are driven, ink is ejected from the nozzles.

[0030] As shown in FIG. 4, the nozzle portions 231 to 238 are arranged side by side in the Y direction. The nozzle portions 231, 232, 233, and 234 are arranged from the center Yo of the head 23 in the Y direction toward the Y1 side. The nozzle portions 235, 236, 237, and 238 are arranged from the center Yo of the head 23 in the Y direction toward the Y2 side. The nozzle portions 231 and 235 eject black ink. The nozzle portions 232 and 236 eject yellow ink. The nozzle portions 233 and 237 eject cyan ink. The nozzle portions 234 and 238 eject magenta ink. That is, in the head 23, the nozzle portions 231 to 238 are arranged such that the nozzle portions ejecting ink of the same color are positioned line-symmetrically with respect to the center Yo in the Y direction.

[0031] FIG. 5 is a diagram showing a schematic arrangement of the nozzles N that constitute the nozzle sections 231 and 235. As shown in FIG. 5, each of the nozzle sections 231 and 235 is made up of a plurality of nozzle rows Nq. Each nozzle row Nq is made up of a plurality of nozzles N arranged at a constant interval D in the X direction. Each nozzle row Nq has a length L in the X direction. The plurality of nozzle rows Nq are arranged at intervals in the Y direction. The nozzles N of the nozzle portions 231 and 235 are arranged with their phases different from each other in the X direction. That is, the nozzles N of the nozzle portions 231 and 235 are arranged alternately in the X direction. When viewed from the Y direction, the nozzles N of the nozzle portion 235 are located at a distance D between the nozzles N of the nozzle portion 231. That is, when viewed from the Y direction, the nozzles N of the nozzle portions 231 and 235 that eject ink of the same color are arranged consecutively in the X direction.

[0032] Although not shown in the drawings, the other nozzle sections have the same configuration as the nozzle sections 231 and 235. Furthermore, similar to the nozzle sections 231 and 235, the nozzle sections that eject ink of the same color (nozzle sections 232 and 236; nozzle sections 233 and 237; nozzle sections 234 and 238) are arranged such that their phases in the X direction are different from each other.

[0033] As shown in FIG. 4, the nozzle portions 241 to 248 of the head 24 have the same configuration as the nozzle portions 231 to 238 of the head 23, and therefore detailed description thereof will be omitted. As with the head 23, the nozzle portions 241 to 248 of the head 24 are arranged so that the nozzle portions ejecting ink of the same color are positioned line-symmetrically with respect to the Y-direction center Yo. The nozzle portions 241 and 245 eject black ink. The nozzle portions 242 and 246 eject yellow ink. The nozzle portions 243 and 247 eject cyan ink. The nozzle portions 244 and 248 eject magenta ink. The nozzle portions ejecting ink of the same color (nozzle portions 241 and 245; nozzle portions 242 and 246; nozzle portions 243 and 247; nozzle portions 244 and 248) are arranged such that their phases in the X direction are different from each other.

[0034] It should be noted that the configuration shown here is merely an example, and settings such as the head, nozzle section, nozzle row, number of nozzles, number of ink colors, and allocation of ink colors to each nozzle section can be changed as appropriate.

[0035] When looking at head unit 22 from the Y direction, nozzle units 231-238 of head 23 and nozzle units 241-248 of head 24 are continuous in the X direction. Heads 23 and 24 are arranged with their positions shifted in the Y direction, but by moving head unit 22 in the Y direction using movement mechanism 29 (see FIG. 2), it is possible to make heads 23 and 24 eject ink at the same position in the Y direction. In other words, the nozzle units of head 23 and head 24, each having a nozzle row Nq (see FIG. 5) of length L, can be considered to constitute one nozzle row of length 2L that is continuous in the X direction.

[0036] Specifically, a combination of nozzle parts located at the same distance from the Y-direction center Yo in each head 23, 24 constitutes one nozzle row that is continuous in the X direction. As shown in Fig. 4, combinations of nozzle part 231 and nozzle part 241, nozzle part 232 and nozzle part 242, nozzle part 233 and nozzle part 243, nozzle part 234 and nozzle part 244, nozzle part 235 and nozzle part 245, nozzle part 236 and nozzle part 246, nozzle part 237 and nozzle part 247, and nozzle part 238 and nozzle part 248 each form one nozzle row that is continuous in the X direction.

[0037] As shown in Fig. 4, head 23 is provided with a tilt axis TA that extends along the Z direction. Heads 23 and 24 are provided so as to be rotatable about the tilt axis TA by a tilt mechanism (not shown). The tilt axis TA is provided in end region 23a on the X2 side of head 23. The tilt axis TA is provided near a corner on the Y2 side of end region 23a. As shown in FIG. 3, a knob 225 for adjusting the tilt of head 23 (hereinafter simply referred to as "knob 225") is provided on the front of head 23. Knob 225 is linked to a tilt mechanism (not shown). When knob 225 is moved clockwise, head 23 rotates clockwise (see FIG. 4). When knob 225 is moved counterclockwise, head 23 rotates counterclockwise (see FIG. 4). The knob 225 may be, for example, a dial knob that provides a clicking sensation each time it is rotated by a predetermined angle.

[0038] As shown in FIG. 4, in the head 24, similarly to the head 23, a tilt axis TA is provided in the vicinity of the corner on the Y2 side of the end region 24a on the X2 side. The head 24 is also provided with a tilt mechanism (not shown), and like the head 23, is rotatable around the tilt axis TA.

[0039] As shown in FIG. 3, the head 24 is provided on its front side with a knob 225 that has the same function as the knob 225 of the head 23 . The head 24 is further provided with a displacement mechanism (not shown), such as a slider, that displaces the head 24 in the X direction. In addition to the knob 225, a displacement adjustment knob 226 (hereinafter simply referred to as "knob 226") is provided on the front side of the head 24. The knob 226 is linked to a displacement mechanism (not shown). For example, when the knob 226 is moved clockwise, the head 24 is displaced to the X2 side in the X direction (see FIG. 4). When the knob 226 is moved counterclockwise, the head 24 is displaced to the X1 side in the X direction (see FIG. 4). The knob 226 can be, for example, a dial knob that provides a clicking sensation each time it is rotated by a predetermined angle.

[0040] The tilt mechanism for heads 23 and 24 and the displacement mechanism for head 24 are provided for the purpose of, for example, inspecting, cleaning, replacing, and other operations of nozzles. After the operations, heads 23 and 24 are adjusted using knob 225 so that they are not tilted. The not tilted state is a state in which the nozzle rows Nq of each of heads 23 and 24 are parallel to the X direction. Furthermore, the position of the head 24 in the X direction is adjusted by the knob 226 so that the end region 24a of the head 24 overlaps with the head 23 when viewed from the Y direction.

[0041] By adjusting the positions of the heads 23 and 24 in this way, the dot positions of the heads 23 and 24 are aligned.

[0042] FIG. 6 is a diagram showing an example of printing when the dot positions of the heads 23 and 24 are aligned. FIG. 6 shows an example in which a single continuous line S is formed by the heads 23 and 24 at a position Ya in the Y direction. As described above, when printing on the medium M, the controller 27 controls the movement mechanism 29 to move the heads 23 and 24 to the dot positions included in the print data and eject ink from the nozzles.

[0043] For example, as shown in (a) of FIG. 6, ink is ejected from the nozzle portion 234 of the head 23 at position Ya in the Y direction to form a line S1 parallel to the X direction. The line S1 has a length L corresponding to the length in the X direction of the nozzle row Nq that constitutes the nozzle portion 234. Next, as shown in (b) of FIG. 6, the nozzle portion 244 of the head 24 is moved to position Ya in the Y direction to eject ink, forming a line S2 parallel to the X direction. The line S2 has a length L in the X direction that corresponds to the nozzle row Nq that constitutes the nozzle portion 244. The X1 side of the line S1 formed by the nozzle portion 234 and the X2 side of the line S2 formed by the nozzle portion 244 are connected. This forms a line S that is continuous in the X direction and has a length of 2L.

[0044] In this way, by ejecting ink while moving the heads 23 and 24 from the Y2 side to the Y1 side in the Y direction, the nozzle portions of the heads 23 and 24 can be treated as one nozzle row that is continuous in the X direction. However, if the dot positions of the heads 23 and 24 do not match, this may affect the continuity of the nozzle portions of the heads 23 and 24.

[0045] The position adjustment of the heads 23, 24 is performed visually by the user. Therefore, tilt and misalignment of the heads 23, 24 may occur that cannot be detected with the naked eye. Alternatively, tilt and misalignment may occur due to manufacturing errors or wear of the heads 23, 24. In such cases, even if the controller 27 controls the heads 23, 24 to eject ink at the same dot positions in the print data, misalignment may occur in the positions where the ink ejected from the heads 23, 24 land (actual dot positions). If the ink landing positions (actual dot positions) of the heads 23, 24 do not match, this may affect the continuity between the nozzle portions of the heads 23 and 24, potentially affecting the quality of the printed material.

[0046] Fig. 7 is a diagram showing an example of printing when the dot positions of heads 23 and 24 do not match. Like Fig. 6, Fig. 7 shows an example in which, at position Ya in the Y direction, line S1 is formed by nozzle portion 234 of head 23 and line S2 is formed by nozzle portion 244 of head 24. Note that Fig. 7 exaggerates the inclination and positional deviation of lines S1 and S2.

[0047] FIG. 7(a) is a diagram showing an example of printing when the head 24 is tilted counterclockwise. In this case, the line S2 formed on the head 24 also becomes tilted and non-parallel to the X direction.

[0048] FIG. 7(b) is a diagram showing a print example when the heads 23 and 24 are misaligned in the Y direction. FIG. 7B shows a case where the dot positions of the head 24 are shifted to the Y1 side in the Y direction relative to the dot positions of the head 23. The line S1 formed by the head 23 is located at a position Ya in the Y direction, whereas the line S2 formed by the head 24 is located on the Y1 side of Ya.

[0049] FIG. 7(c) is a diagram showing a print example when the heads 23 and 24 are misaligned in the X direction. 7(c) shows a case where the dot positions of head 24 are shifted toward the X1 side in the X direction relative to the dot positions of head 23. In this case, when viewed from the Y direction, a gap occurs between line S1 formed by head 23 and line S2 formed by head 24.

[0050] 7, the line S of length 2L that is continuous in the X direction as shown in Fig. 6 is not formed properly. In other words, if the dot positions of the heads 23, 24 do not match due to tilt or misalignment of the heads 23, 24, this could affect the quality of the print formed by the heads 23, 24.

[0051] In this embodiment, the controller 27 executes a correction mode for correcting tilt and positional deviation of the heads 23 and 24. The correction mode is executed by the user selecting it from a menu displayed on the operation panel 26, for example. In the correction mode, the controller 27 prints the following test pattern on the medium M. 50 test patterns for tilt correction Test pattern 60 for Y-axis misalignment correction Test pattern 70 for X-axis misalignment correction

[0052] Correction using the test patterns 50, 60, and 70 can be performed, for example, in the following procedure. FIG. 8 is a flowchart showing an example of a correction procedure. First, the test pattern 50 is used to correct the tilt of the heads 23 and 24 (step S1). Next, the test pattern 60 is used to correct the positional deviation of the heads 23 and 24 in the Y direction (step S2). Next, the test pattern 70 is used to correct the positional deviation of the heads 23 and 24 in the X direction (step S3). The details of each test pattern and the correction method using each test pattern will be described below.

[0053] FIG. 9 is a diagram showing a test pattern 50 for tilt correction. The X, Y, and Z directions in FIG. 9 indicate the directions when the medium M is positioned on the platen 21 (see FIG. 1). 9, the tilt correction test pattern 50 is divided into an area 51 formed by the head 23 and an area 52 formed by the head 24. The area 51 is divided into an area 51A for coarse adjustment and an area 51B for fine adjustment. The area 52 is divided into an area 52A for coarse adjustment and an area 52B for fine adjustment.

[0054] The area 51A for coarse adjustment is a black pattern formed by the nozzle portion 231 and the nozzle portion 235 of the head 23 (see FIG. 4). The fine adjustment area 51B is a magenta pattern formed by the nozzle portion 234 and the nozzle portion 238 of the head 23 (see FIG. 4). The area 52A for coarse adjustment is a black pattern formed by the nozzle portion 241 and the nozzle portion 245 of the head 24 (see FIG. 4). The fine adjustment area 52B is a magenta pattern formed by the nozzle portion 244 and the nozzle portion 248 of the head 24 (see FIG. 4). That is, each area is formed by a combination of nozzle portions that eject ink of the same color in each of the heads 23 and 24.

[0055] Regions 51A, 51B, 52A, and 52B have a configuration in which a counterclockwise arrow 54 and a clockwise arrow 55 are arranged side by side within a rectangular base 53. As described above, regions 51A, 51B, 52A, and 52B are each made of the same color ink, but in FIG. 9, for ease of understanding, the base 53 and the arrows 54 and 55 are hatched differently.

[0056] Since the regions 51A, 51B, 52A, and 52B have the same configuration, the configuration of the region 51A will be described in detail as a representative. FIG. 10 is an enlarged view of the area enclosed by the frame A in FIG. The base 53 shown in Fig. 9 is composed of a set of multiple baselines 530 extending in the Y direction shown in Fig. 10. The multiple baselines 530 are aligned in the X direction at small intervals from each other, so that the base 53 as a whole is visually recognized as a rectangular base 53.

[0057] The arrow 54 and the arrow 55 shown in Fig. 9 are respectively made up of a set of multiple rectangular blocks 540 and a set of blocks 550 shown in Fig. 10. The blocks 540 and 550 are formed between multiple baselines 530. The blocks 540 and 550 are formed with a gap between them in the Y direction. As a result, the arrow 54, which is a set of blocks 540, and the arrow 55, which is a set of blocks 550, are positioned such that they do not overlap in the Y direction.

[0058] The blocks 540 that make up the arrow 54 are formed adjacent to the baseline 530 on the X1 side (the lower side in the drawing) of the baseline 530. A collection of multiple blocks 540 is visually recognized as the counterclockwise arrow 54.

[0059] The blocks 550 that make up the arrow 55 are formed adjacent to the X2 side (upper side in the drawing) of the baseline 530. A collection of multiple blocks 550 is visually recognized as the arrow 55 going clockwise.

[0060] FIG. 11 is a diagram showing a method for forming the test pattern 50. As shown in FIG. Fig. 11 shows, as an example, a method for forming region 51A. A baseline 530 of region 51A is formed by nozzle portion 231 of head 23. Blocks 540 and 550 are formed by nozzle portion 235 of head 23. Fig. 11 schematically shows the arrangement of nozzles that make up nozzle portions 231 and 235, and the correspondence between baseline 530 formed by each nozzle and blocks 540 and 550. In Fig. 11, nozzles are shown as rectangles for ease of understanding.

[0061] As shown in FIG. 11, nozzles N1a, N1b, N1c, N1d, N1e, . . . of the nozzle section 231 are arranged from the X2 side toward the X1 side in the X direction. Nozzles N5a, N5b, N5c, N5d, N5e, N5f, etc. of nozzle portion 235 are arranged from the X2 side toward the X1 side in the X direction. The nozzles of nozzle portion 235 are arranged with a phase shift in the X direction relative to the nozzles of nozzle portion 231. In other words, the nozzles of nozzle portion 231 and the nozzles of nozzle portion 235 are positioned alternately in the X direction.

[0062] FIG. 11 illustrates three combinations P1, P2, and P3 of a baseline 530 and blocks 540 and 550. In combination P1, baseline 530 is formed by nozzle N1a, block 540 is formed by nozzle N5b located on the X1 side of nozzle N1a, and block 550 is formed by nozzle N5a located on the X2 side of nozzle N1a. As a result, blocks 540 and 550 are formed adjacent to each other on the X1 and X2 sides of the baseline 530. Combination P1 has a width of 3 dots in the X direction.

[0063] A gap of one dot is provided between combination P1 and combination P2, meaning that no ink is ejected from nozzle N1b.

[0064] The baseline 530 of the combination P2 is formed by the nozzle N1c. The block 540 is formed by the nozzle N5d located on the X1 side of the nozzle N1c. The block 550 is formed by the nozzle N5c located on the X2 side of the nozzle N1c. A gap of one dot is provided between combination P2 and combination P3, meaning that no ink is ejected from nozzle N1d. The baseline 530 of combination P3 is formed by nozzle N1e, block 540 is formed by nozzle N5f on the X1 side of nozzle N1e, and block 550 is formed by nozzle N5e on the X2 side of nozzle N1e. Similar to combination P1, combinations P2 and P3 also have a width of 3 dots in the X direction.

[0065] In this way, the baseline 530 is formed using every other nozzle of the nozzle section 231. The block 540 is formed by the nozzles of the nozzle section 235 that are adjacent on one side in the X direction (X1 side) to the nozzles of the nozzle section 231 that form the baseline 530. The block 550 is formed by the nozzles of the nozzle section 235 that are adjacent on the other side in the X direction (X2 side) to the nozzles of the nozzle section 231 that form the baseline 530. In other words, the blocks 540 and 550 are arranged so that their positions are shifted from each other in the X direction and they do not overlap.

[0066] Fig. 11 shows test pattern 50 formed when there is no tilt in head 23. As shown in Fig. 4, nozzle portion 231 that forms baseline 530 is farther from tilt axis TA than nozzle portion 235 that forms blocks 540 and 550. As will be described in detail later, this difference in distance from tilt axis TA causes a change in the positional relationship between baseline 530 and blocks 540 and 550 when head 23 is tilted.

[0067] The other regions are formed in the same manner as region 51A. 9, the base 53 (base line 530) is formed by the nozzle portion 234 of the head 23. The arrows 54 and 55 (blocks 540 and 550) are formed by the nozzle portion 238. In the coarse adjustment region 52A, the base 53 (base line 530) is formed by the nozzle portion 241 of the head 24. The arrows 54 and 55 (blocks 540 and 550) are formed by the nozzle portion 245. In the fine adjustment region 52B, the base 53 (base line 530) is formed by the nozzle portion 244 of the head 24. The arrows 54 and 55 (blocks 540 and 550) are formed by the nozzle portion 248. In this way, in both regions, the base 53 (base line 530) is formed by a nozzle portion that is far from the tilt axis TA, and the arrow 54 (block 540) and the arrow 55 (block 550) are formed by nozzle portions that are close to the tilt axis TA.

[0068] FIG. 12 is a diagram illustrating the change in the test pattern 50 when the head 23 is tilted. Figure 12(a) is a diagram showing the displacement of the nozzle portions 234, 238 when the head 23 is tilted clockwise (CW). Figure 12(a) shows the nozzle portions 234, 238 with a long distance between them to make it easier to understand the effect of the tilt of the head 23. Figure 12(a) also shows the positional relationship between the nozzle portions 234, 238 schematically to make it easier to understand. FIG. 12(b) is a diagram illustrating the change in the area 51B formed by the nozzle portions 234 and 238 when the head 23 is tilted clockwise (CW). 12(a), the dashed line indicates the head 23 when not tilted, and the solid line indicates the head 23 tilted clockwise (CW). As shown in FIG. 12(a), when the head 23 is tilted clockwise (CW), the nozzle portions 234, 238 provided on the head 23 are displaced to the X2 side in the X direction.

[0069] As shown in FIG. 12(b), in response to the displacement of the nozzle portions 234 and 238, the baseline 530 and blocks 540 and 550 formed by these nozzle portions also displace in the X direction. Note that the nozzle portions 234, 238 are also displaced in the Y direction due to the tilt of the head 23, but in Figure 12 (b) for ease of understanding, the displacement in the Y direction is ignored, and the baseline 530 and blocks 540, 550 are shown parallel to the Y direction.

[0070] 12(a), when head 23 rotates, the farther a nozzle portion is from tilt axis TA, which is the center of rotation, the greater the amount of displacement in the X direction. The amount of displacement ΔXA in the X direction of nozzle portion 234 farther from tilt axis TA is greater than the amount of displacement ΔXB in the X direction of nozzle portion 238 closer to tilt axis TA (ΔXA>ΔXB).

[0071] The difference in the amount of displacement of the nozzle portions 234 and 238 is also reflected in the amount of displacement in the X direction of the baseline 530 formed by them and the blocks 540 and 550. In other words, the amount of displacement in the X direction of the baseline 530 is greater than that of the blocks 540 and 550. Therefore, as shown in FIG. 12(b), the baselines 530 of the combinations P1 to P3 are displaced toward the X2 side relative to the blocks 540 and 550 in the same combination. As shown in FIG. 11, when the head 23 is not tilted, the baseline 530 is located between the blocks 540 and 550. As shown in FIG. 12(b), as the baseline 530 is displaced toward the X2 side, the baseline 530 of the combination P1 is separated from the block 540 of the same combination P1 and partially overlaps with the block 550. Similar changes occur in the combinations P2 and P3. This change in the relative positions of the baseline 530 and the blocks 540 and 550 appears throughout the entire region 51B.

[0072] Here, in the human visual sense, when lines are far apart within the same area, the color appears darker, and when lines are close to each other or in contact with each other, the color appears lighter. That is, a phenomenon occurs in which arrow 54, which is a collection of blocks 540 that are spaced apart from baseline 530, appears darker than arrow 55, which is a collection of blocks 550 that partially overlap baseline 530. 12(a), head 23 is tilted clockwise (CW), so knob 225 needs to be turned counterclockwise (CCW) to adjust the tilt of head 23. As shown in FIG. 12(b), the user can correct the tilt of head 23 by turning knob 225 counterclockwise (CCW) in the direction indicated by arrow 54, which appears darker.

[0073] FIG. 13 is a diagram illustrating the change in the test pattern 50 when the head 23 is tilted. Figure 13(a) is a diagram schematically showing the displacement of the nozzle portions 234, 238 when the head 23 is tilted counterclockwise (CCW). Figure 13(b) is a diagram explaining the change in the test pattern 50 and the rotation direction of the knob 225 when the head 23 is tilted counterclockwise (CCW). Figure 13(b) ignores displacement in the Y direction, as in Figure 12(b), and shows the baseline 530 and blocks 540, 550 parallel to the Y direction.

[0074] 13(a), when head 23 is tilted counterclockwise CCW, nozzle portions 234, 238 provided on head 23 are displaced toward the X1 side in the X direction. The amount of displacement ΔXC in the X direction of nozzle portion 234 farther from tilt axis TA is greater than the amount of displacement ΔXD in the X direction of nozzle portion 238 closer to tilt axis TA (ΔXC>ΔXD).

[0075] 13(b), baseline 530 is displaced toward the X1 side relative to blocks 540 and 550. Baselines 530 of combinations P1 to P3 are spaced apart from blocks 550 of the same combination and partially overlap block 540. This causes a phenomenon in which arrow 55, which is a collection of blocks 550, appears darker than arrow 54, which is a collection of blocks 540. 13(a), head 23 is tilted counterclockwise (CCW), and therefore knob 225 needs to be turned clockwise (CW) to adjust the tilt of head 23. That is, the user can correct the tilt of head 23 by turning knob 225 clockwise (CW) in the direction indicated by arrow 55, which appears darker.

[0076] In this way, blocks 540 and 550 are formed on the X1 and X2 sides of baseline 530. Furthermore, the nozzle units that form blocks 540 and 550 are closer to tilt axis TA than the nozzle unit that forms baseline 530. This creates a difference in the amount of displacement between baseline 530 and blocks 540 and 550 when head 23 is tilted, causing baseline 530 to displace relative to blocks 540 and 550. Depending on the tilt direction of head 23, baseline 530 displaces toward either the X1 side or the X2 side, creating a difference in distance between baseline 530 and blocks 540 and 550. This difference in distance creates a difference in density between arrows 54 and 55. The user can determine whether the correction direction for tilting head 23 is toward X2 (clockwise CW) or X1 (counterclockwise CCW).

[0077] Here, the individual baseline 530 and blocks 540 and 550 are very small. For example, if only one combination P1 of the baseline 530 and the blocks 540 and 550 is printed on the medium M, a magnifying glass would be needed to grasp the difference in distance between them. In this embodiment, a combination of multiple baselines 530 and blocks 540, 550 is printed, and arrows 54, 55, which are collections of blocks 540 and 550, are formed within a base 53, which is a collection of baselines 530. As described above, with human vision, when lines are farther apart within the same area, the color appears darker, and when lines are close or touching, the color appears lighter. In the arrows 54, 55, which are a collection of lines, this difference in density is even more visible.

[0078] In the embodiment, furthermore, the figures formed by the collection of blocks 540, 550 are arrows 54, 55 indicating the direction of correction of the tilt of head 23 (rotation direction of tilt axis TA). That is, arrow 54, which becomes darker as head 23 tilts toward the X2 side (clockwise CW), is displayed as counterclockwise CCW. Arrow 55, which becomes darker as head 23 tilts toward the X1 side (counterclockwise CCW), is displayed as clockwise CW.

[0079] For example, if only one combination P1 of baseline 530 and blocks 540 and 550 is printed on medium M, it is difficult to intuitively know which direction to turn knob 225 due to the difference in their distances. By assigning the indication of the direction opposite to the tilt direction of head 23, i.e., the correction direction, to arrows 54 and 55, which appear darker depending on the tilt direction of head 23, the user can intuitively know the direction to turn knob 225.

[0080] In the test pattern 50, an area 51 indicating the tilt of the head 23 and an area 52 indicating the tilt of the head 24 are formed on the same medium M. Therefore, the user can adjust both the heads 23 and 24 from the single test pattern 50. When heads 23, 24 are not tilted, there is no difference in density between arrows 54 and 55. The user rotates knob 225 according to the difference in density between arrows 54 and 55, prints test pattern 50 again, and checks the change in density between arrows 54 and 55. The user repeats this process to adjust heads 23, 24 until the difference in density between arrows 54 and 55 disappears.

[0081] As shown in FIG. 9, area 51 of test pattern 50 is divided into area 51A for coarse adjustment and area 51B for fine adjustment. Area 52 is also divided into area 52A for coarse adjustment and area 52B for fine adjustment. In the early stage when the tilt of heads 23, 24 is large, the user performs coarse adjustment using areas 51A, 52A, and once the tilt correction has progressed, performs fine adjustment using areas 51B, 52B. Note that FIG. 9 illustrates the stage of performing tilt correction using areas 51B, 52B for fine adjustment. The coarse adjustment regions 51A and 52A are formed by a combination of nozzle parts whose distance in the Y direction is short (close). The fine adjustment regions 51B and 52B are formed by a combination of nozzle parts whose distance in the Y direction is long (far). As a result, the influence of the tilt of the heads 23 and 24 is more pronounced in the fine adjustment regions 51B and 52B than in the coarse adjustment regions 51A and 52A.

[0082] FIG. 14 is a diagram for explaining the positional relationship of the nozzle portions of the head 23. As shown in FIG. Figure 14(a) is a diagram schematically illustrating the positional relationship between nozzle portions 231 and 235 that form region 51A (see Figure 9) and nozzle portions 234 and 238 that form region 51B (see Figure 9) of head 23. Figure 14(b) is a diagram illustrating the difference in the amount of displacement of each nozzle portion when head 23 is tilted. 14(a), the distance D3 between the nozzle portions 234 and 238 that form the fine adjustment region 51B is longer than the distance D2 between the nozzle portions 231 and 235 that form the coarse adjustment region 51A. Furthermore, the nozzle portion 234 that forms the baseline 530 of the region 51B is farther from the tilt axis TA than the nozzle portion 231 that forms the baseline 530 of the region 51A. The nozzle portion 238 that forms the blocks 540 and 550 of the region 51B is closer to the tilt axis TA than the nozzle portion 235 that forms the blocks 540 and 550 of the region 51A.

[0083] 14(b), when head 23 is tilted, the difference in displacement in the X direction between nozzle portions 234 and 238 (ΔXA-ΔXB) is greater than the difference in displacement in the X direction between nozzle portions 231 and 235 (ΔXE-ΔXF). Due to this difference in displacement, when head 23 is tilted, the relative displacement between baseline 530 and blocks 540 and 550 is greater in region 51B than in region 51A.

[0084] Fig. 15 is a diagram illustrating displacement of region 51A and region 51B in the X direction when the head 23 is tilted significantly. Fig. 15(a) shows region 51A, and Fig. 15(b) shows region 51B. Fig. 15 shows the case when the head 23 is tilted clockwise. 15(a), when the tilt of head 23 is large, baseline 530 is displaced relatively significantly toward X1 even in region 51A. Baseline 530 of combinations P1 and P2 partially overlaps with block 550 in the same combination and is separated from block 540. This makes arrow 54 corresponding to the rotation direction (counterclockwise) of knob 225 appear darker. On the other hand, in region 51B, baseline 530 is displaced toward X2 more than in region 51A. Baselines 530 of combinations P1 and P2 do not overlap with block 550 in the same combination. Furthermore, baseline 530 of combination P2 approaches block 540 of another combination P1. This may make the difference in density between arrows 54 and 55 unclear, or may cause arrow 55 facing the opposite direction of rotation of knob 225 (counterclockwise) to appear darker. Therefore, in the initial stage when the tilt of the head 23 is large, coarse adjustment is performed using the area 51A where the influence of the tilt of the head 23 is small.

[0085] Fig. 16 is a diagram illustrating displacement of region 51A and region 51B in the X direction when the tilt of head 23 is small. Fig. 16(a) shows region 51A, and Fig. 16(b) shows region 51B. Fig. 16 shows the case when head 23 is tilted clockwise.

[0086] As the coarse adjustment progresses and the tilt of head 23 decreases, the displacement of baseline 530 decreases in region 51A. Baseline 530 of combinations P1 and P2 does not overlap with block 550 and is closer to block 540, so the difference in density between arrows 54 and 55 becomes less apparent. On the other hand, in region 51B, the displacement of baseline 530 is greater than in region 51A, so baseline 530 partially overlaps with block 550 and is separated from block 540 on the X1 side. This makes arrow 54, which corresponds to the rotation direction (counterclockwise) of knob 225, appear darker. In this way, at a stage where the correction of the tilt of the head 23 has progressed, it is possible to perform fine adjustment of the angle of the head 23 using the region 51B that is significantly affected by the tilt of the head 23.

[0087] Although detailed explanation will be omitted, the head 24 can also be adjusted coarsely using the area 52A and adjusted finely using the area 52B. In the test pattern 50, the areas 51A and 52A for coarse adjustment and the areas 51B and 52B for fine adjustment are printed on the same medium M. The user does not need to select the coarse adjustment and fine adjustment modes before printing. The user can visually compare the areas 51A and 52A with the areas 51B and 52B in the test pattern 50, allowing for a smooth transition from coarse adjustment to fine adjustment.

[0088] The amount of rotation of the heads 23 and 24 by the knob 225 may be different for coarse adjustment and fine adjustment. For example, for coarse adjustment, the knob 225 may be rotated five clicks, whereas for fine adjustment, the knob 225 may be rotated three clicks. 9, two sets of arrows 54, 55 are printed in each of the regions 51A, 51B, 52A, and 52B. If only one set of arrows 54, 55 is printed, the difference in density may not be properly represented due to errors. In this embodiment, multiple sets of arrows 54, 55 are printed to take errors into account. When making adjustments using each of the areas 51A, 51B, 52A, and 52B, the user can make the adjustments so that there is no difference in density between the two sets of arrows 54 and 55. Note that three or more sets of arrows 54 and 55 may be printed in each of the areas 51A, 51B, 52A, and 52B.

[0089] After the tilt correction of the heads 23 and 24 using the test pattern 50 is completed, the positional deviation in the Y direction is corrected using the test pattern 60 (FIG. 8, step S2). The test pattern 60 is formed by a combination of nozzle portions that form a continuous nozzle row in the heads 23 and 24. As described above, in this embodiment, there are eight combinations, but in step S2, the test pattern 60 is formed using one combination of nozzle portions.

[0090] Here, an example will be described in which a test pattern 60 is formed by combining the nozzle portion 234 of the head 23 and the nozzle portion 244 of the head 24. It should be noted that the heads 23 and 24 are not provided with a Y-direction displacement mechanism. In this embodiment, if a positional deviation in the Y direction is confirmed in the test pattern 60, the positional deviation in the Y direction is corrected by correcting the dot position data included in the print data.

[0091] FIG. 17 is a diagram showing a test pattern 60 for correcting positional deviation in the Y direction. Fig. 18 is a diagram illustrating a method for forming the test pattern 60. Fig. 18(a) is a diagram illustrating the formation of the first line portion 610. Fig. 18(b) is a diagram illustrating the formation of the second line portion 620. The X, Y, and Z directions in Figures 17 and 18 indicate the directions when the medium M is positioned on the platen 21 (see Figure 1). Figures 17 and 18 show the test pattern 60 formed when the dot positions of the head 23 and the head 24 are aligned.

[0092] As shown in FIG. 17, the test pattern 60 has first lines 61 formed by the nozzle portions 234 of the head 23 and second lines 62 formed by the nozzle portions 244 of the head 24. 18(a), the first lines 61 are lines that extend parallel to the X direction. A plurality of first lines 61 are arranged in the Y direction at intervals D4 to form a first line portion 610 having a width W in the Y direction. 17, in the test pattern 60, a plurality of first line portions 610 are formed at intervals in the Y direction. Fig. 17 shows an example in which four first line portions 610 are formed.

[0093] 18(b), the second lines 62 are lines that extend parallel to the X direction. A plurality of second lines 62 are arranged in the Y direction at intervals D4 to form a second line portion 620 having a width W in the Y direction.

[0094] The second lines 62 are formed between the multiple first lines 61 in the Y direction. The second lines 62 are located within a distance D4 between the first lines 61 in the Y direction. The second lines 62 are formed at positions shifted toward the X2 side of the first lines 61 in the X direction. When viewed from the Y direction, the first lines 61 and the second lines 62 partially overlap. That is, the test pattern 60 has an overlapping portion 630 where the first lines 61 and the second lines 62 overlap when viewed in the Y direction. In the overlapping portion 630, the first lines 61 and the second lines 62 are arranged alternately in the Y direction. In other words, in the overlapping portion 630, the second lines 62 are arranged so as to fill the gap D4 between adjacent first lines 61. The actual distance D4 is so small that the overlapping portion 630 appears to the naked eye as a filled in area, i.e., a solid area, as shown in FIG.

[0095] 17, a second line portion 620 is formed every other one of four first line portions 610. That is, an overlap portion 630 is formed between two first line portions 610. An overlap portion 630 is not formed between the first line portions 610.

[0096] 17, the test pattern 60 has a first reference line 64 formed on the Y1 side of each first line portion 610. The first reference line 64, like the first line portion 610, is formed by the nozzle portion 234 of the head 23. 18, the first reference line 64 is a line that extends parallel to the X direction and has the same length in the X direction as the first line 61. The first reference line 64 is formed at the same position as the first line portion 610 in the X direction.

[0097] The test pattern 60 has second reference lines 65 formed on the Y1 side of each second line portion 620. The second reference lines 65 are formed by the nozzle portions 244 of the head 24, similar to the second line portions 620. The second reference line 65 is a line that extends parallel to the X direction and has the same length in the X direction as the second line 62. The second reference line 65 is formed at the same position in the X direction as the second line portion 620. The second reference line 65 is formed at the same position in the Y direction as the first reference line 64. The second reference line 65 is formed with its position shifted to the X2 side of the first reference line 64. In other words, the first reference line 64 and the second reference line 65 are printed on the medium M with portions overlapping each other. As a result, the first reference line 64 and the second reference line 65 are visually recognized as one continuous line.

[0098] As shown in FIG. 17, the test pattern 60 has a sample block 660. The sample block 660 is formed on the Y2 side of the first line portion 610. The sample block 660 is a so-called "solid" rectangular shape filled with ink of a single color. The sample block 660 is formed only by the nozzle portion 234 of the head 23. The sample block 660 is formed at the same position as the first line portion 610 in the X direction.

[0099] The test pattern 60 is formed by moving the heads 23 and 24 in the same direction. The first line portion 610, first reference line 64, and sample block 660 of the test pattern 60 are formed, for example, by ejecting ink while moving the head 23 from the Y2 side to the Y1 side in the Y direction. The second line portion 620 and second reference line 65 of the test pattern 60 are formed, for example, by ejecting ink while moving the head 24, similar to the head 23, from the Y2 side to the Y1 side in the Y direction.

[0100] 19 is a diagram illustrating a change in test pattern 60 when there is a positional deviation in the Y direction between heads 23 and 24. Fig. 19 shows a case where the dot positions of head 24 are deviated to the Y2 side relative to the dot positions of head 23. As the dot positions of the head 24 are shifted to the Y2 side, the second line 62 formed by the head 24 is displaced to the Y2 side. 19, in the overlapping portion 630, the second line 62 approaches the first line 61 or overlaps with the first line 61. The gap D4 between the first lines 61 is not filled by the second line 62, and the overlapping portion 630 is visually recognized as a portion where ink is not ejected. In other words, the overlapping portion 630 is in a state where uneven coloring occurs, and is no longer visually recognized as a solid color as shown in FIG. By comparing the state of the solidly filled sample block 660 (see FIG. 17) with the state of the overlapping portion 630, the user can understand that there is a deviation in the Y direction between the dot positions of head 23 and head 24.

[0101] As shown in FIG. 19 , as the dot positions of the head 24 are shifted toward the Y2 side, the second reference line 65 formed by the head 24 is also shifted toward the Y2 side, similar to the second line 62. This causes a shift in the Y-direction positions of the first reference line 64 and the second reference line 65, and the second reference line 65 does not overlap the first reference line 64 but is positioned further toward the Y2 side than the first reference line 64. By comparing the first reference line 64 and the second reference line 65, the user can determine that the dot positions of the head 24 are shifted toward the Y2 side relative to the dot positions of the head 23. Furthermore, by looking at the amount of shift of the second reference line 65 relative to the first reference line 64, the user can roughly determine the amount of shift of the dot positions of the head 24.

[0102] 17, the test pattern 60 includes first line portions 610 that do not have overlapping portions 630. If overlapping portions are provided in all of the first line portions 610, it may be difficult to distinguish between the first line portions 610 and the second line portions 620 when the orientation of the medium M is changed, for example. The user can distinguish between the first line portions 610 and the second line portions 620 using the first line portions 610 that do not have overlapping portions 630 as a reference.

[0103] Although not shown, the controller 27 (see FIG. 1) accepts input of correction values ​​for correcting the dot positions of the nozzle portions 241 to 248 of the head 24, for example, in correction mode. The controller 27, for example, causes the operation panel 26 (see FIG. 1) to display an input section for correction values. The user inputs a correction value according to the direction and amount of deviation of the dot positions of the head 24 confirmed from the test pattern 60. At this time, the user may input a correction value only for the nozzle portion 244 of the head 24. Alternatively, the user may input the same correction value for all the nozzle portions 241 to 248 of the head 24.

[0104] The user repeats printing the test pattern 60 and inputting the correction values ​​until the overlapping portion 630 (see FIG. 19) becomes solid like the sample block 660 (see FIG. 17). This makes it possible to correct positional deviation in the Y direction of the heads 23 and 24. During printing, the controller 27 controls the movement of the head 24 by reflecting the correction value in the dot positions of the head 24 in the print data.

[0105] It is also possible to provide a Y-direction displacement mechanism in the head 24, and correct the positional deviation between the heads 23 and 24 in the Y direction by the displacement mechanism.

[0106] After the correction of the positional deviation of the heads 23 and 24 in the Y direction is completed, the test pattern 70 is used to correct the positional deviation of the heads 23 and 24 in the X direction (FIG. 8, step S3). Like the test pattern 60, the test pattern 70 is formed using the nozzle portion 234 of the head 23 and the nozzle portion 244 of the head 24.

[0107] FIG. 20 is a diagram showing a test pattern 70 for correcting positional deviation in the X direction. The X, Y, and Z directions in Fig. 20 indicate the directions when the medium M is positioned on the platen 21. Fig. 20 also shows the test pattern 70 formed when the dot positions of the nozzle portions 234 and 244 are aligned.

[0108] As shown in FIG. 20, the test pattern 70 is made up of three figures: a rectangular block 71, a trapezoidal block 81, and a line 91. Each figure in test pattern 70 is bounded by a line segment HL parallel to the X direction, with the region on the X2 side formed by the nozzle portion 234 of head 23 and the region on the X1 side formed by the nozzle portion 244 of head 24. Note that the boundary located on line segment HL is not noticeable in reality, but is shown in bold in FIG. 20 for clarity. Furthermore, although the entire test pattern 70 is formed using magenta ink, in FIG. 20, for ease of understanding, the areas formed by the nozzle portion 234 and the nozzle portion 244 are hatched differently.

[0109] FIG. 21 is an enlarged view of the area enclosed by the frame A in FIG. The block 71 has an area 71A (first area) formed by the head 23 on the X2 side of the line segment HL. The block 71 has an area 71B (second area) formed by the head 24 on the X1 side of the line segment HL. As shown in FIG. 21, at the boundary between the regions 71A and 71B, a concavo-convex shape is formed across the line segment HL. The unevenness is formed by a linear portion 72 (first linear portion) located on the X2 side of the line segment HL, a linear portion 73 (second linear portion) located on the X1 side of the line segment HL, and a linear portion 74 (third linear portion) connecting the ends of the linear portions 72 and 73. Linear portions 72 and 73 extend parallel to line segment HL. Linear portions 72 and 73 are alternately arranged in the Y direction. Linear portion 74 extends in a direction perpendicular to line segment HL. When viewed from above, rectangular projections and depressions are arranged continuously in the Y direction at the boundary between regions 71A and 71B.

[0110] The linear portions 72, 73, and 74 are formed by overlapping the ink ejected from the nozzle portion 234 of the head 23 and the ink ejected from the nozzle portion 244 of the head 24. That is, the linear portions 72, 73, and 74 are formed by overlapping the end portion on the X1 side of the region 71A and the end portion on the X2 side of the region 71B.

[0111] When the dot positions of the heads 23 and 24 are aligned, the uneven shape across the line segment HL is difficult to see with the naked eye.

[0112] As shown in FIG. 20, trapezoidal block 81 has a region 81A on the X2 side formed by head 23 and a region 81B on the X1 side formed by head 24, with line segment HL as the boundary. Block 81 has an end 82 on the Y1 side and an end 83 on the Y2 side. End 82 is a straight line extending parallel to the X direction. End 83 is a diagonal line inclined with respect to the X direction. End 83 is inclined in the direction approaching the Y2 side as it moves from the X2 side to the X1 side.

[0113] The line 91 is a straight line extending in the X direction. The line 91 has an area 91A on the X2 side formed by the head 23 and an area 91B on the X1 side formed by the head 24, with the line segment HL as the boundary.

[0114] Figure 22 is a diagram illustrating changes in test pattern 70 when heads 23 and 24 are misaligned in the X direction. Figure 22 shows the area around line segment HL of block 71. (a) of Figure 22 shows a case where the dot positions of head 24 are misaligned to the X1 side of the dot positions of head 23. (b) of Figure 22 shows a case where the dot positions of head 24 are misaligned to the X2 side of the dot positions of head 23.

[0115] 22(a), when the head 24 is misaligned toward the X1 side in the X direction, the entire region 71B of the block 71 is displaced away from the region 71A. As a result, the ends of the regions 71A and 71B do not overlap, and a gap is created at the boundary between the regions 71A and 71B. Here, the gap refers to a portion where no ink is ejected.

[0116] Specifically, a gap 75A is formed between the linear portion 72 in region 71A and the linear portion 72 in region 71B. A gap 75B is formed between the linear portion 73 in region 71A and the linear portion 73 in region 71B. The gaps 75A on the X2 side of the line segment HL and the gaps 75B on the X1 side are alternately arranged in the Y direction and are formed continuously.

[0117] When gaps 75A and 75B are formed in block 71, the user can understand that the dot positions of head 24 are shifted toward the X1 side with respect to the dot positions of head 23. The user can correct the positional shift of head 24 in the X direction by displacing head 24 toward the X2 side using a displacement mechanism (not shown).

[0118] 22(b), when the head 24 is misaligned to the X2 side in the X direction, the entire region 71B of the block 71 is displaced in a direction approaching the region 71A. As a result, the end of the region 71B is displaced further toward the X2 side than the end of the region 71A, and overlaps with the region 71A. Specifically, linear portions 72 of region 71B overlap region 71A, forming high-density region 76A. Linear portions 73 of region 71B overlap region 71A, forming high-density region 76B. High-density regions 76A and 76B are regions where the color appears darker due to the overlapping of ink. The high concentration regions 76A on the X1 side of the line segment HL and the high concentration regions 76B on the X2 side are alternately arranged in the Y direction and are continuously formed.

[0119] When high-density regions 76A and 76B are formed in block 71, the user can understand that the dot positions of head 24 are shifted toward the X2 side relative to the dot positions of head 23. The user can adjust the positional shift of head 24 by displacing head 24 toward the X1 side using a displacement mechanism (not shown).

[0120] Although not shown in the figure, if the dot positions of head 24 are misaligned in the X direction, gaps or high-density areas will also appear in blocks 81 and lines 91 shown in Fig. 23. The user can also ascertain the misalignment of heads 23, 24 in the X direction from blocks 81 and lines 91.

[0121] Here, if the misalignment of the heads 23 and 24 in the X direction is slight, the gaps 75A and 75B or the high-density regions 76A and 76B may be small and difficult to see individually. In particular, because the nozzle portions 234 and 244 eject ink of the same color, the high-density regions are difficult to see. In the block 71, the gaps 75A and 75B or the high-density regions 76A and 76B are formed with their positions shifted to the X1 and X2 sides of the line segment HL, and further appear alternately and continuously in the Y direction. Therefore, the gaps 75A and 75B or the high-density regions 76A and 76B are easily seen as a continuous pattern.

[0122] Although the embodiment has been described above in which the positional deviation of the head 24 in the X direction is determined from the test pattern 70, it is also possible to determine the positional deviation in the Y direction and the tilt of the heads 23 and 24 from the test pattern 70.

[0123] FIG. 23 is a diagram showing the test pattern 70 when the heads 23 and 24 are misaligned in the Y direction. FIG. 23 shows the test pattern 70 when the dot positions of the nozzle portions 244 of the head 24 are misaligned to the Y1 side. In block 71, region 71B is shifted to the Y1 side, causing a shift in the Y-direction position of the linear portion 74 of region 71A and the linear portion 74 of region 71B. As a result, a high-concentration region is formed in the linear portion 74 on the Y1 side, and a gap is generated in the linear portion 74 on the Y2 side. In the block 81, the region 81B is shifted to the Y1 side, so that a step occurs at the position where the line segment HL passes between the Y-direction ends 82 and 83. In particular, the step is easily visible at the end 83, which is a hypotenuse. Also on the line 91, a step occurs at the position where the line segment HL passes because the area 91B is shifted to the Y1 side. From these phenomena, the user can grasp the shift in dot position in the test pattern 70. Furthermore, although not shown in the drawings, if either head 23 or 24 is tilted, area 91A or 91B of line 91 will also be tilted, and line 91 will no longer be a continuous straight line in the X direction. The user can grasp the tilt of head 23 or 24 from this phenomenon.

[0124] If these phenomena are observed in the test pattern 70, it is possible that the tilt correction or dot position correction was insufficient, and so it is possible to return to the adjustment using the test patterns 50 and 60.

[0125] In the above example, linear portion 72 (first linear portion), linear portion 73 (second linear portion), and linear portion 74 (third linear portion) are formed as the ends of region 71A and region 71B of block 71, but it is also possible to grasp the positional deviation of heads 23, 24 using only linear portions 72 to 74. In test pattern 70, instead of printing the entire block 71, heads 23, 24 may print only the concave-convex shape consisting of linear portions 72 to 74.

[0126] When the correction of the positional deviation in the X direction using the test pattern 70 is completed, the correction process may be ended as shown in FIG. Alternatively, the test pattern 60 may be formed using a combination of nozzle parts other than the nozzle parts 234 and 244 of the heads 23 and 24. Even if the misalignment in the Y direction of the reference nozzle parts 234 and 244 is corrected, there may be a slight misalignment in the Y direction in other combinations of nozzle parts. By forming the test pattern 60 using other combinations of nozzle parts, it is possible to perform position correction with higher accuracy.

[0127] Furthermore, if the Y-direction misalignment correction or the X-direction misalignment correction is performed using the test patterns 60 and 70 after the tilt correction using the test pattern 50 is completed, the tilt correction may be performed again using the test pattern 50. The correction process may be terminated when correction is no longer required for all test patterns.

[0128] In this way, by performing adjustments using test patterns 50, 60, and 70, the printer 1 can print with the dot positions of heads 23 and 24 aligned, thereby improving print quality. Note that "a state in which the dot positions (ink landing positions) of heads 23 and 24 are aligned" does not only include a state in which they are perfectly aligned, but also a state in which there is a degree of misalignment that does not pose a problem in terms of print quality.

[0129] In the embodiment, an example has been described in which the test patterns 50, 60, and 70 are printed separately on the medium M, but the present invention is not limited to this. The test patterns 50, 60, and 70 may be printed on the same medium M.

[0130] As described above, the test pattern 60 described in the embodiment has, for example, the following configuration.

[0131] (1) The test pattern 60 is printed on the medium M using ink ejected from the head 23 (first inkjet head) and the head 24 (second inkjet head). The test pattern 60 has first lines 61 and second lines 62 printed alternately in the Y direction (first direction). The first line 61 is formed by ink ejected from a plurality of nozzles N of the head 23 that are aligned in the X direction (second direction) that is perpendicular to the Y direction. The second line 62 is formed by ink ejected from a plurality of nozzles N of the head 24 aligned in the X direction.

[0132] If the dot positions of heads 23 and 24 are misaligned in the Y direction, the positional relationship between the first line 61 and the second line 62 changes in the test pattern 60. From the positional relationship between the first line 61 and the second line 62, the user can grasp the misalignment in the Y direction between the dot positions of heads 23 and 24.

[0133] (2) The test pattern 60 has an overlapping portion 630 where the first line 61 and the second line 62 overlap when viewed in the Y direction. The overlapping portion 630 is visually recognized as a filled-in area when the landing position (dot position) of ink ejected from nozzle N of head 23 and the landing position (dot position) of ink ejected from nozzle N of head 24 coincide in the Y direction.

[0134] If the deviation in the dot positions of the heads 23, 24 is slight, the change in the positional relationship between the first line 61 and the second line 62 is difficult to see with the naked eye. By arranging the second line 62 to fill the gap D50 of the first line 61, if the dot positions of the heads 23, 24 are aligned, the overlapping portion 630 will be visually recognized as a filled-in area. In other words, if the dot positions of the heads 23, 24 are deviated in the Y direction, the overlapping portion 630 will have uneven paint. The user can easily see the deviation in position with the naked eye.

[0135] (3) The test pattern 60 further includes a first reference line 64 and a second reference line 65 . The first reference line 64 is formed by ink ejected from the nozzles N of the head 23. The second reference line 65 is formed by ink ejected from the nozzles N of the head 24. When the landing position (dot position) of ink ejected from nozzle N of head 23 and the landing position (dot position) of ink ejected from nozzle N of head 24 coincide in the Y direction, the first reference line 64 and the second reference line 65 have an overlapping area.

[0136] When the dot positions of head 23 and head 24 are misaligned in the Y direction, second reference line 65 does not overlap first reference line 64, but is shifted to the Y1 side or Y2 side of first reference line 64 depending on the direction of misalignment of head 24. By providing the first reference line 64 and the second reference line 65 in addition to the overlapping portion 630 where the lines are densely packed, the direction of deviation of the head 24 can be easily grasped.

[0137] (4) In block 71 of test pattern 70 (pattern), linear portions 72 (first linear portions) located on the X2 side (one side) of a line segment HL (virtual line) along the Y direction and linear portions 73 (second linear portions) located on the X1 side (other side) are arranged alternately in the Y direction. The linear portion 72 and the linear portion 73 are formed by the ink ejected from the nozzles N of the head 23 and the ink ejected from the nozzles N of the head 24 overlapping each other.

[0138] If the dot positions of heads 23, 24 are misaligned in the X direction, the linear portions 72 and 73 formed by heads 23, 24 will not overlap and will be printed with a misalignment in the X direction. Even if the misalignment in the X direction is slight, the misalignment is easily noticeable because the linear portions 72 and 73 are alternately arranged in the Y direction. The user can easily see with the naked eye the misalignment in the X direction of the dot positions of heads 23, 24 from test pattern 70.

[0139] (5) Block 71 of test pattern 70 has area 71A (first area) and area 71B (second area). Area 71A is located on the X2 side (one side) of line segment HL and is filled with ink ejected from nozzle N of head 23. Area 71B is located on the X1 side (other side) of line segment HL and is filled with ink ejected from nozzle N of head 24. Linear portion 72 and linear portion 73 are formed by opposing ends of region 71A and region 71B. (6) When the landing position (dot position) of ink ejected from nozzle N of head 23 does not match the landing position (dot position) of ink ejected from nozzle N of head 24 in the X direction, gaps 75A, 75B or high-density regions 76A, 76B occur at the boundary between region 71A and region 71B.

[0140] Gaps 75A, 75B or high-density regions 76A, 76B that occur at the boundaries between filled-in regions 71A, 71B are easily noticeable, making it easy for the user to recognize misalignment from test pattern 70. Furthermore, gaps 75A, 75B or high-density regions 76A, 76B appear alternately and continuously in the Y direction along linear portions 72 and 73, making them easier for the user to see.

[0141] (7) In the test pattern 70, the linear portion 72 and the linear portion 73 are parallel to the line segment HL. The ends of the linear portion 72 and the linear portion 73 are connected by a linear portion 74 (third linear portion) that is perpendicular to the line segment HL. The linear portion 74 is formed by the ink ejected from the nozzles N of the head 23 and the ink ejected from the nozzles N of the head 24 overlapping each other.

[0142] Linear portion 72, linear portion 73, and linear portion 74 form an uneven shape at the boundary between the first region and the second region. Because the uneven shape is easily noticeable, the user can easily determine the misalignment of heads 23, 24. Furthermore, if heads 23, 24 are misaligned in the Y direction, gaps 75A, 75B or high-density regions 76A, 76B will occur along linear portion 74, so the user can also determine the misalignment of heads 23, 24 in the Y direction from test pattern 70.

[0143] The same effect can be obtained in the printing method and printing apparatus for printing the test patterns 60 and 70 described above.

[0144] (Variation 1) FIG. 24 is a diagram showing a method for forming a test pattern 50A according to the first modification. In the embodiment, an example has been described in which nozzle sections in which nozzles are arranged with a phase shift in the X direction form test pattern 50. In Modification 1, an example will be described in which test pattern 50A is formed by nozzle sections in which nozzles are arranged in the same phase in the X direction. 24 illustrates an example in which the nozzles of the nozzle portions 231A and 235A are arranged in the same phase. Other nozzle portions can be formed in the same manner as long as they are a combination of nozzle portions in the same phase.

[0145] As shown in FIG. 24, nozzles N1a, N1b, N1c, N1d, N1e, N1f, N1g, . . . of the nozzle portion 231A are arranged at intervals D from the X2 side toward the X1 side in the X direction. Nozzles N5a, N5b, N5c, N5d, N5e, N5f, N5g, . . . of the nozzle portion 235A are arranged at intervals D from the X2 side toward the X1 side in the X direction. The nozzles of the nozzle portion 231A are arranged at the same positions in the X direction as the nozzles of the nozzle portion 235A. That is, the nozzles of the nozzle portion 231A and the nozzles of the nozzle portion 235A are arranged in the same phase in the X direction.

[0146] 24 shows two combinations P4 and P5 of a baseline 530 and blocks 540 and 550. The baseline 530 is formed by the nozzle section 231A that is far from the tilt axis TA, and the blocks 540 and 550 are formed by the nozzles of the nozzle section 235A that is close to the tilt axis TA. In combination P4, baseline 530 is formed by nozzle N1b of nozzle section 231A. Block 540 is formed by nozzle N5c on the X1 side of nozzle N1b. Block 550 is formed by nozzle N5a on the X2 side of nozzle N1b. Nozzle N5b, which is in the same phase as nozzle N1b, is not used. Nozzles N1a and N1c, which are in the same phase as nozzles N5a and N5c, are not used. The blocks 540 and 550 are formed with a one dot interval in the X direction relative to the baseline 530. The combination P4 is formed with a width of five dots in the X direction.

[0147] A gap of three dots is provided between combination P4 and combination P5 in the X direction, so nozzles N1d and N5d are not used.

[0148] In combination P5, baseline 530 is formed by nozzle N1f of nozzle section 231A. Block 540 is formed by nozzle N5g on the X1 side of nozzle N1f. Block 550 is formed by nozzle N5e on the X2 side of nozzle N1f. Nozzle N5f, which is in phase with nozzle N1f, is not used. Nozzles N1e and N1g, which are in phase with nozzles N5e and N5g, are not used. Like combination P4, combination P5 is formed with a width of 5 dots in the X direction.

[0149] In this way, in variant 1, as in the embodiment, block 540 is formed by nozzles adjacent to the nozzles that formed baseline 530 on the X1 side in the X direction, and block 550 is formed by nozzles adjacent to the nozzles on the X2 side. However, in Modification 1, by using a nozzle unit in which nozzles are arranged in the same phase, one combination of baseline 530 and blocks 540, 550 is formed with a wide width of five dots in the X direction. Also, a gap of three dots is provided in the X direction between combinations P4 and P5. As described above, in the embodiment, one combination of baseline 530 and blocks 540, 550 is formed with a width of three dots in the X direction, and a gap of one dot is provided in the X direction between combinations P1 to P3 (see FIG. 11).

[0150] That is, in test pattern 50A of modification 1, the distance in the X direction between baseline 530 and blocks 540 and 550 is greater than in test pattern 50 of the embodiment. Test pattern 50A has a lower line density than test pattern 50. That is, test pattern 50A is less affected by the tilt of heads 23 and 24 than test pattern 50. Therefore, test pattern 50A can be used, for example, for coarse adjustment when the tilt of heads 23 and 24 is large.

[0151] The printing device 1 may print the test pattern 50A of the modified example for rough adjustment when the tilt of the heads 23, 24 is large, and print the test pattern 50 of the embodiment for fine adjustment when the tilt has become small.

[0152] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the technical concept of the present invention.

[0153] (Addendum) (A) a test pattern printed on a medium by ink ejected from a first inkjet head and a second inkjet head, a first linear portion located on one side of an imaginary line along a first direction and a second linear portion located on the other side, the first linear portion and the second linear portion being printed alternately arranged in the first direction; A test pattern characterized in that the first linear portion and the second linear portion are formed by overlapping ink ejected from the nozzles of the first inkjet head and ink ejected from the nozzles of the second inkjet head. (B) A method for printing a test pattern on a medium by ejecting ink from a first inkjet head and a second inkjet head, printing first linear portions located on one side of an imaginary line along a first direction and second linear portions located on the other side of the imaginary line in an alternate arrangement; A method for printing a test pattern, characterized in that the first linear portion and the second linear portion are formed by superimposing ink ejected from the nozzles of the first inkjet head and ink ejected from the nozzles of the second inkjet head. (C) A printing device that prints a test pattern on a medium by ejecting ink from a first inkjet head and a second inkjet head, printing first linear portions located on one side of an imaginary line along a first direction and second linear portions located on the other side of the imaginary line in an alternate arrangement; A test pattern printing device, characterized in that the first linear portion and the second linear portion are formed by overlapping ink ejected from the nozzles of the first inkjet head and ink ejected from the nozzles of the second inkjet head. [Explanation of symbols]

[0154] 1 Printing device 2 Main body 3 Mounting stand 21 Platen 22 Head 23 Inkjet head (first inkjet head) 231 Nozzle section (first nozzle section) 234 Nozzle section (third nozzle section) 235 Nozzle section (second nozzle section) 238 Nozzle section (4th nozzle section) 24 inkjet head (second inkjet head) 241 Nozzle section (first nozzle section) 244 Nozzle section (third nozzle section) 245 Nozzle section (second nozzle section) 248 Nozzle section (4th nozzle section) 225 Tilt adjustment knob 226 Displacement adjustment knob 25 UV irradiation unit 26 Operation Panel 27 Controller 28 Ink supply mechanism 281 Ink Bottle 282 Ink supply path 29 Moving mechanism 291 Carriage 292 Guide Rail 30 Feed mechanism 50 test patterns 51A, 51B, 52A, 52B area 53 Base 530 Baseline 54 Arrow (first shape) Block 540 (1st Block) 55 Arrow (Second Shape) 550 Block (2nd Block) 60 test patterns 610 First Line Division 61 First Line 620 Second Line Division 62 Second Line 630 Overlap section 64 First Reference Line 65 Second Reference Line 660 Sample Block 70 test patterns 71 blocks 71A area (1st area) 71B area (second area) 72 Linear portion (first linear portion) 73 Linear portion (second linear portion) 74 Linear section (third linear section) 75A, 75B gap 76A, 76B High concentration area 81 blocks 81A, 81B area 82, 83 End 91 Line 91A, 91B area TA Tilt Axis HL Line (virtual line) M medium Y Main scanning direction (first direction) X Sub-scanning direction (second direction)

Claims

1. a test pattern printed on a medium by ink ejected from the first inkjet head and the second inkjet head, having first and second lines printed alternately in a first direction; the first line is formed by ink ejected from a plurality of nozzles of the first inkjet head arranged in a second direction perpendicular to the first direction, the second line is formed by ink ejected from a plurality of nozzles of the second inkjet head that are aligned in the second direction, the first line and the second line have an overlapping portion where they overlap when viewed from the first direction, a test pattern characterized in that the overlapping portion is visually recognized as a filled area when the landing position of ink ejected from the nozzles of the first inkjet head and the landing position of ink ejected from the nozzles of the second inkjet head are aligned in the first direction.

2. a first reference line formed by ink ejected from the nozzles of the first inkjet head; a second reference line formed by ink ejected from the nozzles of the second inkjet head; 2. The test pattern according to claim 1, wherein when a landing position of ink ejected from the nozzles of the first inkjet head and a landing position of ink ejected from the nozzles of the second inkjet head are aligned in the first direction, the first reference line and the second reference line have an overlapping area.

3. The pattern further includes first linear portions located on one side of an imaginary line along the first direction and second linear portions located on the other side, the first linear portions being arranged alternately in the first direction, 3. The test pattern according to claim 1, wherein the first linear portion and the second linear portion are formed by overlapping ink ejected from the nozzles of the first inkjet head and ink ejected from the nozzles of the second inkjet head.

4. the pattern has a first region on one side of the virtual line that is filled with ink ejected from the nozzles of the first inkjet head, and a second region on the other side that is filled with ink ejected from the nozzles of the second inkjet head, 4. The test pattern according to claim 3, wherein the first linear portion and the second linear portion are formed by opposing ends of the first region and the second region.

5. 5. The test pattern according to claim 4, wherein when a landing position of ink ejected from the nozzles of the first inkjet head and a landing position of ink ejected from the nozzles of the second inkjet head do not coincide in the second direction, a gap or a high-density area occurs at a boundary between the first area and the second area.

6. the first linear portion and the second linear portion are parallel to the virtual line, end portions of the first linear portion and the second linear portion are connected to each other by a third linear portion that is perpendicular to the virtual line, 6. The test pattern according to claim 3, wherein the third linear portion is formed by overlapping ink ejected from the nozzles of the first inkjet head and ink ejected from the nozzles of the second inkjet head.

7. A method for printing a test pattern on a medium by ejecting ink from a first inkjet head and a second inkjet head, The first lines and the second lines are printed alternately in a first direction; the first line is formed by ejecting ink from a plurality of nozzles of the first inkjet head that are aligned in a second direction perpendicular to the first direction; forming the second line by ejecting ink from a plurality of nozzles of the second inkjet head that are aligned in the second direction; the first line and the second line have an overlapping portion where they overlap when viewed from the first direction, a printing method for a test pattern, characterized in that the overlapping portion is visually recognized as a filled-in area when the landing position of ink ejected from the nozzles of the first inkjet head and the landing position of ink ejected from the nozzles of the second inkjet head are aligned in the first direction.

8. A printing device that prints a test pattern on a medium by ejecting ink from a first inkjet head and a second inkjet head, The first lines and the second lines are printed alternately in a first direction; the first line is formed by ejecting ink from a plurality of nozzles of the first inkjet head that are aligned in a second direction perpendicular to the first direction; forming the second line by ejecting ink from a plurality of nozzles of the second inkjet head that are aligned in the second direction; the first line and the second line have an overlapping portion where they overlap when viewed from the first direction, a printing device characterized in that the overlapping portion is visually recognized as a filled-in area when the landing position of ink ejected from the nozzles of the first inkjet head and the landing position of ink ejected from the nozzles of the second inkjet head are aligned in the first direction.

Images