Printing apparatus and printing method

Abstract

The invention provides a printing apparatus and a printing method, which can inhibit the generation of light-color stripes between nozzle rows along the relative movement direction of a medium due to the flow of dots on the medium. The transfer unit relatively moves the medium in a relative movement direction intersecting the nozzle arrangement direction with respect to the print head. In the overlapping portion of the print head, the first nozzle row is located on the upstream side of the second nozzle row in the relative movement direction. In the nozzle arrangement direction, the boundary between the first printing region of the first nozzle row and the second printing region of the second nozzle row is located within the range of the overlapping portion. The plurality of first nozzles include normal nozzles located in the first printing area and anti-flow point forming nozzles located at an end portion on the first printing area side in the second printing area. The control unit causes the print head to form a plurality of anti-flow dots that are not adjacent to each other in the relative movement direction by means of the first liquid ejected from the anti-flow dot forming nozzle toward the medium during printing.

Description

Technical Field

[0001] The present invention relates to a printing device and a printing method having an overlapping portion in which nozzle rows partially overlap. Background Art

[0002] Patent Document 1 discloses a printer that performs printing using a printing unit in which a first nozzle array group and a second nozzle array group are arranged in a direction intersecting a predetermined direction. In the first nozzle array group, first nozzle arrays that eject a first liquid are arranged in the predetermined direction, with the ends of adjacent first nozzle arrays overlapping. In the second nozzle array group, second nozzle arrays that eject a second liquid are arranged in the predetermined direction, with the ends of adjacent second nozzle arrays overlapping.

[0003] In the printer, an error in the installation position in the predetermined direction occurs between nozzle arrays that eject different liquids, or an error in the installation position in the predetermined direction occurs between nozzle arrays that eject the same liquid. The error between nozzle arrays that eject the same liquid causes uneven density, such as black or white streaks, in the printed result at the overlapping portion of the nozzle arrays ejecting the same liquid.

[0004] Even when the use ranges of the first and second nozzles in the overlapping portion of a first nozzle array and a second nozzle array ejecting the same liquid are determined so that the printing area of ​​the first nozzle array and the printing area of ​​the second nozzle array are continuous, light streaks such as white streaks, which appear as the background color of the medium, may occur. Therefore, an improvement is sought to eliminate light streaks caused by the overlapping portion of nozzle arrays ejecting the same liquid.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-195897 Summary of the Invention

[0006] The printing device of the present invention has the following mode, that is, it comprises: a printing head having a first nozzle array formed by arranging a plurality of first nozzles capable of ejecting a first liquid onto a medium in a predetermined nozzle arrangement direction, and a second nozzle array formed by arranging a plurality of second nozzles capable of ejecting the first liquid onto the medium in the nozzle arrangement direction; a transfer unit that moves the medium relative to the printing head in a relative movement direction intersecting the nozzle arrangement direction with respect to the printing head; and a control unit that controls the ejection of liquid including the first liquid by the printing head, wherein the printing head has a portion of the first nozzle array and a portion of the second nozzle array that are aligned when viewed from the relative movement direction. The first nozzle array is located on the upstream side of the second nozzle array in the relative movement direction, and the boundary between the first printing area of ​​the first nozzle array and the second printing area of ​​the second nozzle array in the nozzle arrangement direction is located within the range of the overlapping portion. The multiple first nozzles include a normal nozzle located in the first printing area and an anti-flow point forming nozzle located at the end of the first printing area side in the second printing area. The control unit causes the print head to form a plurality of non-adjacent anti-flow points in the relative movement direction by ejecting the first liquid from the anti-flow point forming nozzle toward the medium during printing.

[0007] In addition, the printing method of the present invention has the following mode, that is, it relatively moves the medium in a relative movement direction intersecting with a predetermined nozzle arrangement direction with a print head as a reference, and ejects a liquid containing a first liquid from the print head toward the medium, wherein the print head has a first nozzle array formed by a plurality of first nozzles capable of ejecting the first liquid toward the medium, arranged in the nozzle arrangement direction, and a second nozzle array formed by a plurality of second nozzles capable of ejecting the first liquid toward the medium, arranged in the nozzle arrangement direction, and the print head has an overlapping portion in which a portion of the first nozzle array overlaps a portion of the second nozzle array when viewed from the relative movement direction, and in the overlapping portion, the first nozzle array is located opposite the first nozzle array and the second nozzle array. The two nozzle columns are closer to the upstream side in the relative movement direction. In the nozzle arrangement direction, the boundary between the first printing area of ​​the first nozzle column and the second printing area of ​​the second nozzle column is located within the range of the overlapping part. The multiple first nozzles include a normal nozzle located in the first printing area and an anti-flow point forming nozzle located at the end of the first printing area side in the second printing area. When stripes formed by the flow of the first liquid are generated between the first printing area and the second printing area during printing without using the anti-flow point forming nozzle, a plurality of anti-flow points that are not adjacent to each other in the relative movement direction are formed by spraying the first liquid from the anti-flow point forming nozzle toward the medium.

[0008] Moreover, the printing method of the present invention has the following mode, that is, it relatively moves the medium in a relative movement direction intersecting with a predetermined nozzle arrangement direction with a print head as a reference, and ejects a liquid containing a first liquid from the print head toward the medium, wherein the print head has a first nozzle array formed by a plurality of first nozzles capable of ejecting the first liquid toward the medium, arranged in the nozzle arrangement direction, and a second nozzle array formed by a plurality of second nozzles capable of ejecting the first liquid toward the medium, arranged in the nozzle arrangement direction, and the print head has an overlapping portion in which a portion of the first nozzle array overlaps a portion of the second nozzle array when viewed from the relative movement direction. , in the overlapping portion, the first nozzle array is located upstream of the second nozzle array in the relative movement direction, and when a pair of the first nozzle and the second nozzle having a corresponding relationship between a position in the overlapping portion of the first nozzle array and a position in the overlapping portion of the second nozzle array is defined as a nozzle pair, the overlapping portion has n sets of the nozzle pairs arranged in the nozzle arrangement direction, where n is an integer greater than 2, and the printing method includes: a first test pattern printing step of printing a first test pattern for determining a usage range of the first nozzle and the second nozzle in the overlapping portion on the medium, so that the nozzle pairs in the nozzle pairs are The number of specific nozzle pairs of the first nozzle and the second nozzle used for ejecting the first liquid is m, and the first test pattern is printed, where m is an integer greater than or equal to 0 and less than n. A usage range determining step is performed to determine the usage range based on the concentration of a specific area from a first printing position to a second printing position, wherein the first printing position is a printing position of the first nozzle located closest to the second printing area of ​​the second nozzle column in the first printing area of ​​the first test pattern printed on the medium, and the second printing position is a printing position of the second nozzle located closest to the first printing area in the second printing area of ​​the first test pattern printed on the medium, wherein the plurality of first nozzles include normal nozzles located in the first printing area and anti-flow dot forming nozzles located at an end portion of the second printing area on the first printing area side. The printing method further includes an anti-flow dot forming step in which, when streaks due to the flow of the first liquid occur between the first printing area and the second printing area during printing based on the usage range, a plurality of non-adjacent anti-flow dots are formed by ejecting the first liquid onto the medium from the anti-flow dot forming nozzles. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a block diagram schematically showing a configuration example of a printing device.

[0010] Figure 2 A diagram schematically showing an example of the positional relationship between the print head and the medium.

[0011] Figure 3A This is a diagram schematically showing a part of the first nozzle row and the second nozzle row as an example of an ideal state.

[0012] Figure 3B FIG. 1 is a diagram schematically showing a portion of the first nozzle row and the second nozzle row as a first example of a non-ideal state.

[0013] Figure 3C This is a diagram schematically showing a part of the first nozzle row and the second nozzle row as a second example of a non-ideal state.

[0014] Figure 4 This is a flowchart schematically showing an example of nozzle use range determination processing.

[0015] Figure 5A This figure illustrates the overlapping portion and the first test pattern when the adjustment value is set to 0.

[0016] Figure 5B This figure exemplifies the overlapping portion and the first test pattern when the adjustment value is set to +1.

[0017] Figure 5C This figure illustrates the overlapping portion and the first test pattern when the adjustment value is set to -1.

[0018] Figure 6 A diagram schematically illustrating a print head and main parts of a printed image.

[0019] Figure 7 The figure schematically shows an example of the intervals between the anti-flow points.

[0020] Figure 8 The figure schematically shows an example of the size of the anti-flow point.

[0021] Figure 9 A diagram schematically showing an example of the number of anti-flow point forming nozzles.

[0022] Figure 10 1 is a flowchart schematically showing an example of adjustment processing.

[0023] Figure 11 A diagram schematically illustrating main parts of a print head and a second test pattern.

[0024] Figure 12 This is a flowchart schematically showing an example of print control processing.

[0025] Figure 13 This is a flowchart schematically showing another example of the print control process.

[0026] Figure 14 This is a diagram schematically showing an example of the behavior of the first liquid on the medium when the wettability of the liquid with respect to the medium is low. DETAILED DESCRIPTION

[0027] The following describes embodiments of the present invention. Of course, the following embodiments are merely illustrative of the present invention, and not all of the features shown in the embodiments are essential to the solution provided by the invention.

[0028] (1) Summary of the aspects included in the present invention:

[0029] First, refer to Figures 1 to 14 The examples shown hereof provide an overview of the embodiments of the present invention. Furthermore, the figures in this application are schematic illustrations of examples, and the proportions, shapes, and depths shown in these figures may not always be accurate, the figures may not match, and parts may be omitted. Of course, the elements of this embodiment are not limited to the specific examples shown by the symbols. In the "Overview of the Embodiments of the Present Invention," the content in brackets supplements the preceding words.

[0030] Method 1

[0031] like Figure 1 As exemplified in FIG. 1 and FIG. 2 , a printing device 10 according to one embodiment includes a printing head 19, a transport unit 17, and a control unit 11. Figure 6As illustrated in FIG. 1 , the print head 19 includes a first nozzle array 201 comprising a plurality of first nozzles 211 arranged in a predetermined nozzle array direction D3, capable of ejecting a first liquid LQ1 onto a medium 30; and a second nozzle array 202 comprising a plurality of second nozzles 212 arranged in the nozzle array direction D3, capable of ejecting the first liquid LQ1 onto the medium 30. The transport unit 17 moves the medium 30 relative to the print head 19 in a relative movement direction D1 intersecting the nozzle array direction D3. The control unit 11 controls the ejection of the liquid LQ0 including the first liquid LQ1 by the print head 19. The print head 19 includes an overlapping portion 22 where a portion of the first nozzle array 201 overlaps a portion of the second nozzle array 202 when viewed in the relative movement direction D1. In the overlapping portion 22, the first nozzle array 201 is located upstream S1 of the second nozzle array 202 in the relative movement direction D1. In the nozzle arrangement direction D3, a boundary B1 between the first printing area AR1 of the first nozzle array 201 and the second printing area AR2 of the second nozzle array 202 is located within the overlapping portion 22. The plurality of first nozzles 211 include a normal nozzle NZ1 located in the first printing area AR1 and an anti-flow point forming nozzle NZ2 located at an end of the second printing area AR2 on the first printing area AR1 side. During printing, the control unit 11 ejects the first liquid LQ1 from the anti-flow point forming nozzle NZ2 toward the medium 30, and the print head 19 forms a plurality of non-adjacent anti-flow points DT1 in the relative movement direction D1.

[0032] Experiments have shown that when the wettability of liquid LQ0 relative to the medium 30 is low, the first liquid LQ1 ejected from the first nozzle array 201 flows in a convergent manner on the medium 30, thereby generating light streaks along the relative movement direction D1 of the medium 30 between the nozzle arrays. Light streaks are streaks in which the base color component of the medium 30 appears. In the above-described method, a plurality of non-adjacent flow prevention dots DT1 are formed at the end of the second printing area AR2 on the first printing area AR1 side. This ensures that the first liquid LQ1 in the first printing area AR1 and the first liquid LQ1 in the second printing area AR2 are appropriately connected. This suppresses the generation of light streaks along the relative movement direction D1 between the nozzle arrays ejecting the first liquid LQ1. Therefore, the above-described method can provide a printing device that can suppress the generation of light streaks along the relative movement direction of the medium between the nozzle arrays due to the flow of dots on the medium.

[0033] In the above-mentioned aspects, various examples are given.

[0034] The transport unit may move the medium in the relative movement direction without moving the print head, may move the print head in the direction opposite to the relative movement direction without moving the medium, or may move both the medium and the print head.

[0035] The upstream side in the relative movement direction does not refer to the side the medium is moving toward, but rather the side the medium is moving toward. Therefore, at a certain position in the relative movement direction, the first liquid ejected from the second nozzle row will land after the first liquid ejected from the first nozzle row has landed. When the relative movement direction is the medium's transport direction, the medium is transported from upstream to downstream.

[0036] The anti-flow point forming nozzle may be one nozzle or two or more nozzles.

[0037] The plurality of anti-flow dots being non-adjacent to each other in the relative moving direction means that the plurality of anti-flow dots are formed with a recording rate of 50% or less per pixel in the relative moving direction.

[0038] In the present application, “first”, “second”, etc. are terms used to identify respective components included in a plurality of similar components, and do not indicate order.

[0039] Of course, the above-mentioned remarks also apply in the following manner.

[0040] Method 2

[0041] like Figure 1 、 Figure 13 As illustrated, the present printing apparatus may further include an operation accepting unit 14 for accepting an operation of changing from the anti-flow dot forming nozzle NZ2 to the normal nozzle NZ1. When the change operation is accepted, the control unit 11 may change the anti-flow dot forming nozzle NZ2 to the normal nozzle NZ1 and control the ejection of the liquid LQ0 by the print head 19.

[0042] When the anti-flow dot-forming nozzle NZ2 is replaced with the normal nozzle NZ1, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases. In the case where light streaks are still visible even after the anti-flow dot DT1 is formed, replacing the anti-flow dot-forming nozzle NZ2 with the normal nozzle NZ1 reduces the light streaks. Therefore, this approach can further appropriately suppress streaks along the relative movement direction between nozzle arrays, depending on the type of medium and liquid.

[0043] Method 3

[0044] like Figure 1 、 Figure 8 、 Figure 10 As illustrated, the printing device 10 may further include an operation accepting unit 14 for accepting an operation for setting the size of the anti-flow dots DT1. When the setting operation is accepted, the control unit 11 may cause the print head 19 to form the plurality of anti-flow dots DT1 in the size.

[0045] As the size of the anti-flow dot DT1 increases, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases. While light streaks may still be visible even with a small anti-flow dot DT1, increasing the size of the anti-flow dot DT1 reduces these streaks. Therefore, this approach can further appropriately suppress streaks along the relative movement direction between nozzle arrays.

[0046] Method 4

[0047] A printing method according to one embodiment relatively moves a medium 30 in a relative movement direction D1 intersecting a predetermined nozzle arrangement direction D3 with a print head 19 as a reference, and discharges a liquid LQ0 including a first liquid LQ1 from the print head 19 onto the medium 30. The print head 19 includes a first nozzle array 201 comprising a plurality of first nozzles 211 arranged in the nozzle arrangement direction D3 capable of discharging the first liquid LQ1 onto the medium 30, and a second nozzle array 202 comprising a plurality of second nozzles 212 arranged in the nozzle arrangement direction D3 capable of discharging the first liquid LQ1 onto the medium 30. The print head 19 includes an overlapping portion 22 where a portion of the first nozzle array 201 overlaps a portion of the second nozzle array 202 when viewed in the relative movement direction D1. In the overlapping portion 22, the first nozzle array 201 is located upstream S1 of the second nozzle array 202 in the relative movement direction D1. In the nozzle arrangement direction D3, the boundary B1 between the first printing area AR1 of the first nozzle array 201 and the second printing area AR2 of the second nozzle array 202 is located within the range of the overlapping portion 22. The plurality of first nozzles 211 include a normal nozzle NZ1 located in the first printing area AR1 and an anti-flow point forming nozzle NZ2 located at an end of the second printing area AR2 on the side of the first printing area AR1. Figure 14 As illustrated, in a case where stripes 50 formed by the flow of the first liquid LQ1 are generated between the first printing area AR1 and the second printing area AR2 during printing without using the anti-flow dot forming nozzle NZ2, a plurality of anti-flow dots DT1 that are not adjacent to each other in the relative movement direction D1 are formed by ejecting the first liquid LQ1 from the anti-flow dot forming nozzle NZ2 toward the medium 30.

[0048] The above-described aspect can provide a printing method that can suppress the occurrence of light-colored streaks between nozzle rows along the relative movement direction of the medium due to the flow of dots on the medium.

[0049] Method 5

[0050] Here, n is set to an integer greater than 2, and a pair of the first nozzle 211 and the second nozzle 212 whose positions in the overlapping portion 22 of the first nozzle array 201 correspond to those in the overlapping portion 22 of the second nozzle array 202 is referred to as a nozzle pair. In another embodiment of the printing method, the overlapping portion 22 has n sets of the nozzle pairs arranged in the nozzle arrangement direction D3. Figure 4 As illustrated, the printing method includes the following steps.

[0051] (a1) A first test pattern printing process ST1, in which, when a first test pattern 31 for determining the usage range of the first nozzle 211 and the second nozzle 212 in the overlapping portion 22 is printed on the medium 30, when m is set to an integer greater than 0 and less than n, the number of specific nozzle pairs in the nozzle pair that use the first nozzle 211 and the second nozzle 212 for ejecting the first liquid LQ1 is m groups, and the first test pattern 31 is printed.

[0052] (a2) Use range determination step ST2 of determining the use range based on the density of the specific area 32 from the first printing position to the second printing position.

[0053] The first printing position is the printing position of the first nozzle 211 located at the side of the second printing area AR2 of the second nozzle column 202 in the first printing area AR1 of the first nozzle column 201 in the first test pattern 31 printed on the medium 30. The second printing position is the printing position of the second nozzle 212 located at the side of the first printing area AR1 in the second printing area AR2 of the first test pattern 31 printed on the medium 30. The plurality of first nozzles 211 include a normal nozzle NZ1 located in the first printing area AR1 and an anti-flow point forming nozzle NZ2 located at the end of the second printing area AR2 on the side of the first printing area AR1. Figure 10 、 Figure 12 As exemplified in the examples, the present printing method further includes the following steps.

[0054] (a3) Anti-flow dot forming step ST3, in which a streak 50 (see FIG. 1 ) is generated between the first printing area AR1 and the second printing area AR2 due to the flow of the first liquid LQ1 during printing based on the use range. Figure 14 ), a plurality of flow prevention dots DT1 that are not adjacent to each other in the relative movement direction D1 are formed by the first liquid LQ1 ejected from the flow prevention dot forming nozzle NZ2 toward the medium 30 .

[0055] Experiments have shown that even when the usage ranges of the first and second nozzles 211 and 212 are determined based on the concentration of the specific area 32 of the first test pattern 31, light streaks along the relative movement direction D1 of the medium 30 still occur between the nozzle arrays when the wettability of the liquid LQ0 on the medium 30 is low. This is because the first liquid LQ1 ejected from the first nozzle array 201 initially flows in a convergent manner on the medium 30. In this manner, when streaks 50 due to the flow of the first liquid LQ1 occur between the first and second printing areas AR1 and AR2 during printing based on the determined usage range, multiple flow prevention dots DT1, which are not adjacent to each other in the relative movement direction D1, are formed at the end of the second printing area AR2 on the first printing area AR1 side. This ensures that the first liquid LQ1 in the first and second printing areas AR1 and AR2 are appropriately connected, suppressing light streaks along the relative movement direction D1 between the nozzle arrays ejecting the first liquid LQ1. Therefore, the above-described embodiment can provide a printing method capable of suppressing the occurrence of light-colored streaks between nozzle rows along the relative movement direction of the medium due to the flow of dots on the medium.

[0056] Method 6

[0057] like Figure 8 、 Figure 10 As exemplified above, the printing method may further include the following steps.

[0058] (a4) A size setting acceptance step ST4 of accepting the setting of the size of the anti-flow point DT1.

[0059] In the anti-flow point forming step ST3 , the plurality of anti-flow points DT1 may be formed in the size.

[0060] As the size of the anti-flow dot DT1 increases, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases. While light streaks may still be visible with a small anti-flow dot DT1, increasing the size of the anti-flow dot DT1 reduces these streaks. Therefore, this approach can further suppress streaks along the relative movement direction between nozzle arrays.

[0061] Method 7

[0062] like Figure 7 、 Figure 10 、 Figure 11 As exemplified above, the printing method may further include the following steps.

[0063] (a5) A second test pattern printing process ST5, which forms a second test pattern 35. The second test pattern 35 is formed in a manner including the anti-flow point DT1 by ejecting the first liquid LQ1 from the first nozzle array 201 and the second nozzle array 202 toward the medium 30, and includes a plurality of independent patterns 36 that change the spacing between the anti-flow points DT1 in the relative movement direction D1.

[0064] (a6) A spacing determination step ST6 of determining the spacing between the flow prevention dots DT1 used in the flow prevention dot forming step ST3 based on the second test pattern 35 .

[0065] As the spacing between the anti-flow dots DT1 decreases, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases. While light streaks may still be visible even with widely spaced anti-flow dots DT1, these streaks are reduced as the spacing between the anti-flow dots DT1 decreases. Therefore, this approach can further appropriately suppress streaks along the relative movement direction between nozzle arrays.

[0066] Method 8

[0067] In the second test pattern printing step ST5 , the second test pattern 35 may be formed when at least one of the type of the medium 30 and the type of the first liquid LQ1 is changed.

[0068] The degree to which dots on the medium 30 flow varies depending on the combination of the type of medium 30 and the type of liquid LQ0. By forming the second test pattern 35 based on a change in at least one of the type of medium 30 and the type of first liquid LQ1, it is possible to appropriately suppress the occurrence of light streaks between nozzle arrays along the relative movement direction of the medium due to the flow of dots on the medium.

[0069] Furthermore, the above-described method can be applied to a composite device including the above-described printing device, a control method for the above-described printing device, a control program for the above-described composite device, a control program for the above-described printing device, a computer-readable non-transitory medium storing any of the above-described programs, and the like. Any of the above-described devices may also be composed of multiple dispersed components.

[0070] (2) Specific example of printing device:

[0071] Figure 1 The structure of the printing device 10 is schematically illustrated. In the printing device 10, a printing method is implemented. Figure 2 This is a plan view that simply shows an example of the positional relationship between the print head 19 and the medium 30 from an upper viewpoint. Figures 3A to 3C A part of the first nozzle row and the second nozzle row is schematically illustrated.

[0072] Figure 1 The printing device 10 shown includes a control unit 11, a display unit 13, an operation reception unit 14, a storage unit 15, a communication interface 16, a transfer unit 17, a print head 19, and the like. The control unit 11 includes a CPU (Central Processing Unit) 11a, a ROM (Read Only Memory) 11b, and a RAM (Random Access Memory) 11c. The control unit 11 may also include nonvolatile memory, etc. The control unit 11, including the CPU 11a, may also be composed of one or more integrated circuits (ICs).

[0073] The CPU 11a uses the RAM 11c or other memory as a work area and controls the printing device 10 by executing arithmetic operations in accordance with a program 12 stored in the ROM 11b or other memory. The processor is not limited to a single CPU but may be multiple CPUs or a hardware circuit such as an ASIC (Application Specific Integrated Circuit). Furthermore, the CPU and hardware circuit may work in conjunction to perform processing.

[0074] The display unit 13 is a unit for displaying visual information, and may be a liquid crystal display, an organic EL (electroluminescence) display, etc. The display unit 13 may also include a display and a driving circuit for driving the display.

[0075] The operation receiving unit 14 is a unit for receiving user input and may be a physical button, a touch panel, a mouse, a keyboard, or the like. The touch panel may also be implemented as a function of the display unit 13. The display unit 13 and the operation receiving unit 14 may also be referred to as the operation panel of the printing device 10.

[0076] The storage unit 15 may be a solid-state drive, a hard disk drive, or other memory. A portion of the memory included in the control unit 11 may also be considered the storage unit 15. The storage unit 15 may also be considered a portion of the control unit 11. The display unit 13, the operation receiving unit 14, and the storage unit 15 may also be peripheral devices external to the printing device 10.

[0077] The communication I / F 16 is a general term for one or more I / Fs used by the printing device 10 to communicate with external devices via wired or wireless communication in accordance with a predetermined communication protocol including known communication standards. The external device may be a communication device such as a personal computer, server, smartphone, or tablet terminal.

[0078] like Figure 2 As shown, the transfer unit 17 moves the medium 30 in a relative movement direction D1 that intersects the predetermined nozzle arrangement direction D3. If the printing device 10 is a line-type inkjet printer, such as a line printer, the medium 30 continues in the relative movement direction D1, and the transfer unit 17 continuously transports the medium 30 in the relative movement direction D1 during printing. Therefore, the relative movement direction D1 in a line-type printing device is also referred to as the transport direction. It can be said that the transfer unit 17 moves the medium 30 relative to the print head 19 in a predetermined transport direction (relative movement direction D1). The transfer unit 17 may include, for example, rollers that rotate and transport the medium 30, a motor that serves as a power source for the rotation, and the like. The transfer unit 17 may also be a mechanism that carries the medium 30 on a pallet, belt, roller, or the like and transports the medium 30. The medium 30 is, for example, paper, but any medium capable of being printed with liquid LQ0 may also be a material other than paper, such as cloth or film.

[0079] The print head 19 is a unit that performs printing by ejecting liquid LQ0 onto the medium 30 using an inkjet method under the control of the control unit 11. While the liquid LQ0 primarily refers to ink, the print head 19 can also eject liquids LQ0 other than ink. For example, the print head 19 can eject multiple colors of ink, such as C (cyan), M (magenta), Y (yellow), and K (black). Of course, the ink ejected by the print head 19 is not limited to CMYK ink.

[0080] The printing device 10 can be implemented as a single printer, but it can also be implemented as multiple devices or apparatuses connected to each other in a communicative manner. When the printing device 10 is configured as a system composed of multiple devices, for example, it includes an information processing device that functions as the control unit 11, and a printer that includes a transport unit 17 and a print head 19 and performs printing under the control of the information processing device. In this case, the information processing device can be understood as a print control device, an image processing device, or the like.

[0081] exist Figure 2 In FIG, the print head 19 of the line printing device is shown as the print head 19, which includes the print heads 19C, 19M, 19Y, and 19K. The line print heads 19C, 19M, 19Y, and 19K are arranged in sequence along the relative movement direction D1 and fixed on the conveying path of the medium 30. The width direction D2 of the medium 30 intersects the relative movement direction D1. Figure 2 In the figure, the intersection of the relative movement direction D1 and the width direction D2 can be understood as being perpendicular or substantially perpendicular. Figure 2 The nozzle arrangement direction D3 shown is consistent with the width direction D2. The transfer unit 17 transports the medium 30 from the upstream to the downstream of the relative moving direction D1. Hereinafter, the upstream of the relative moving direction D1 is sometimes referred to as the upstream, and the downstream of the relative moving direction D1 is sometimes referred to as the downstream. Figure 2 The relative movement direction D1 shown is upward, so Figure 2 In the above description, the lower side is the upstream side and the upper side is the downstream side. Figure 6 In FIG. 1 , the left side is the upstream side S1 and the right side is the downstream side S2.

[0082] Print heads 19C, 19M, 19Y, and 19K each have multiple nozzle rows. Print head 19C has multiple nozzle rows 20C capable of ejecting C ink. Multiple nozzle rows 20C include nozzle rows 20C1, 20C2, 20C3, 20C4, and 20C5. Print head 19M has multiple nozzle rows 20M capable of ejecting M ink. Multiple nozzle rows 20M include nozzle rows 20M1, 20M2, 20M3, 20M4, and 20M5. Print head 19Y has multiple nozzle rows 20Y capable of ejecting Y ink. Multiple nozzle rows 20Y include nozzle rows 20Y1, 20Y2, 20Y3, 20Y4, and 20Y5. Print head 19K has multiple nozzle rows 20K capable of ejecting K ink. Multiple nozzle rows 20K include nozzle rows 20K1, 20K2, 20K3, 20K4, and 20K5. Of course, the number of nozzle rows constituting the print head 19 corresponding to one type of liquid LQ0 may not be five.

[0083] The print heads 19C, 19M, 19Y, and 19K all have a length in the width direction D2 that can cover the length of the medium 30 in the width direction D2, that is, the width of the medium. Since the structures of the print heads 19C, 19M, 19Y, and 19K are basically the same except for the color of the ink they eject, the print head 19C will be used as a representative for description. The nozzle arrays 20C1, 20C2, 20C3, 20C4, and 20C5 that constitute the print head 19C are all capable of ejecting the first liquid LQ1 (see FIG. 1 ) which is the same liquid LQ0. Figure 1 ) are arranged in the nozzle arrangement direction D3. When focusing on the print head 19M, the M ink is applied to the first liquid LQ1. When focusing on a particular print head 19 and referring to the liquid LQ0 ejected by that print head 19 as the first liquid LQ1, the liquid LQ0 ejected by another print head 19 may also be referred to as the second liquid.

[0084] exist Figure 2 In FIG. 1 , a chip having each nozzle array is shown as a simple rectangle, and the description of each nozzle 21 of the nozzle array is omitted. Figure 2 As shown, the print head 19 includes a plurality of chips arranged in a staggered manner in a continuous manner in the width direction D3, and each chip has a nozzle column. For example, the print head 19C includes a chip having a nozzle column 20C1, a chip having a nozzle column 20C2, a chip having a nozzle column 20C3, a chip having a nozzle column 20C4, and a chip having a nozzle column 20C5. In addition, each chip may also have a plurality of nozzle columns in CMYK. By assembling a plurality of chips into the print head 19, installation errors may occur between the chips. Figure 3A In the figure, each nozzle 21 is shown by a circle. The multiple nozzles 21 in the nozzle row can be arranged in one row or in a staggered manner, that is, in two rows. Here, the nozzle arrangement direction D3 of the multiple nozzles 21 arranged in a staggered manner is set as the arrangement direction of the nozzles 21 in each of the two rows. The interval between adjacent nozzles 21 in the nozzle row, that is, the distance between the nozzles 21 in the nozzle arrangement direction D3 is called the nozzle spacing. The nozzle spacing is fixed in design. The nozzle arrangement direction D3 can be parallel to the width direction D2 or inclined relative to the width direction D2. In short, the nozzle arrangement direction D3 intersects with the relative movement direction D1. In addition, the interval between the nozzles 21 in the width direction D2 can also be understood as the nozzle spacing.

[0085] In this specific example, of two adjacent nozzle rows in the relative movement direction D1 within a print head 19, the upstream nozzle row is referred to as the "first nozzle row," and the downstream nozzle row is referred to as the "second nozzle row." The "first nozzle row" consists of a plurality of "first nozzles" arranged in the nozzle arrangement direction D3, capable of ejecting the first liquid LQ1 onto the medium 30. The "second nozzle row" consists of a plurality of "second nozzles" arranged in the nozzle arrangement direction D3, capable of ejecting the first liquid LQ1 onto the medium 30. The designations "first nozzle row" and "second nozzle row" are simply used for convenience when focusing on specific nozzle rows. For example, when focusing on nozzle rows 20C1 and 20C2 within a print head 19C, the upstream nozzle row 20C2 is referred to as the first nozzle row, while the downstream nozzle row 20C1 is referred to as the second nozzle row. In this case, nozzle row 20C2 can be said to be composed of a plurality of first nozzles ejecting ink C arranged in nozzle arrangement direction D3, and nozzle row 20C1 can be said to be composed of a plurality of second nozzles ejecting ink C arranged in nozzle arrangement direction D3. Similarly, when focusing on nozzle rows 20C4 and 20C5, upstream nozzle row 20C4 is considered the first nozzle row, while downstream nozzle row 20C5 is considered the second nozzle row. In this case, nozzle row 20C4 can be said to be composed of a plurality of first nozzles ejecting ink C arranged in nozzle arrangement direction D3, and nozzle row 20C5 can be said to be composed of a plurality of second nozzles ejecting ink C arranged in nozzle arrangement direction D3. The control unit 11 controls the ejection of liquid LQ0 including first liquid LQ1 by the print head 19 in this manner.

[0086] In this specific example, the ends of adjacent nozzle rows among the plurality of nozzle rows constituting one print head 19 overlap with each other in the nozzle arrangement direction D3. Therefore, it can be said that the print head 19 has an "overlapping portion 22" where a portion of the first nozzle row overlaps a portion of the second nozzle row when viewed from the relative movement direction D1. Figure 2 , the range of each overlapping portion 22 of the print head 19C is shown. In the overlapping portion 22, the first nozzle row is located upstream of the second nozzle row in the relative movement direction D1. The area of ​​the print head 19 where the nozzles 21 are arranged but not within the overlapping portion 22 is referred to as the "normal area."

[0087] In this specific example, a pair of first and second nozzles whose positions in the overlapping portion 22 of the first nozzle array correspond to their positions in the overlapping portion 22 of the second nozzle array is referred to as a "nozzle pair." One overlapping portion 22 has n sets of nozzle pairs arranged in the nozzle arrangement direction D3. n is an integer greater than or equal to 2, for example, n=64. Here, left and right when viewed from an upstream toward downstream point of view are referred to as left and right, respectively. The first nozzle and the second nozzle whose positions in the overlapping portion 22 of the first nozzle array and the overlapping portion 22 of the second nozzle array correspond to each other refer to the first nozzle and the second nozzle whose order in the left-right direction in the overlapping portion 22 is consistent. For example, in the overlapping portion 22 of the nozzle array 20C4 and the nozzle array 20C5, the leftmost nozzle 21 in the nozzle array 20C4 forms a nozzle pair with the leftmost nozzle 21 in the nozzle array 20C5. Based on the same concept, in the overlapping portion 22 of the nozzle row 20C4 and the nozzle row 20C5 , the second nozzle 21 from the left in the nozzle row 20C4 and the second nozzle 21 from the left in the nozzle row 20C5 form a nozzle pair.

[0088] Based on print data representing an image, the control unit 11 causes the print head 19 to eject liquid LQ0 as droplets onto the medium 30. As is well known, the print head 19 is provided with a driver element for each nozzle 21. By controlling the application of a drive signal to the driver element of each nozzle 21 according to the print data, each nozzle 21 is caused to eject or not eject droplets. When droplets from the nozzles 21 land on the medium 30, dots are formed on the medium 30. Thus, the image represented by the print data is printed on the medium 30 as a dot pattern. Here, the print data is assumed to be data indicating the droplet ejection status, such as the presence or absence of droplets, for each pixel and for each CMYK color. In this case, the print data can also be said to be image data indicating the dot formation status, such as the presence or absence of dot formation, for each pixel and for each CMYK color. Droplet ejection can also be referred to as dot-on, and the non-ejection of droplets can also be referred to as dot-off. The control unit 11 controls the transport unit 17 and the print head 19 to discharge droplets such as ink droplets onto the medium 30 passing under the print heads 19C, 19M, 19Y, and 19K, thereby forming a printed image on the medium 30 .

[0089] Figure 3A The overlapping portion 22 and its vicinity are schematically enlarged as an example of an ideal state. The ideal state refers to a state in which there is no or almost no error in the positional relationship between the first nozzle array and the second nozzle array sharing the overlapping portion 22 in the nozzle arrangement direction D3. Figures 3A to 3CIn the embodiment, the nozzle arrangement direction D3 is parallel to the width direction D2. Here, the nozzle array 20C4 of the print head 19C is referred to as the first nozzle array, and the nozzle array 20C5 is referred to as the second nozzle array.

[0090] exist Figures 3A to 3C In the figure, for the sake of convenience, each nozzle 21 constituting a nozzle column is marked with a nozzle number from left to right along the nozzle arrangement direction D3. In addition, the nozzle 21 with the nozzle number # (number) is also simply recorded as nozzle # (number). Figure 3A In the example shown, each nozzle row is composed of 50 nozzles 21, and the range of six consecutive nozzles #45 to #50 in the nozzle row 20C4 and the range of six consecutive nozzles #1 to #6 in the nozzle row 20C5 form an overlapping portion 22. Figure 3A In the example, n=6. Figure 3A In the example of FIG, the range of 38 consecutive nozzles #7 to #44 in each nozzle column corresponds to the normal portion. Figure 3A In FIG. 2 , the nozzle 21 of nozzle number # 46 in the nozzle row 20C4 and the nozzle 21 of nozzle number # 2 in the nozzle row 20C5 are surrounded by a dotted line, indicating that they form a nozzle pair in the overlapping portion 22 .

[0091] exist Figure 3A In the example, the first and second nozzles forming a nozzle pair, for example, nozzle 21 with nozzle number #46 in nozzle row 20C4 and nozzle 21 with nozzle number #2 in nozzle row 20C5, are aligned in width direction D2. Therefore, ideally, the first and second nozzles forming a nozzle pair would eject droplets of the same color onto the same position on medium 30. However, due to individual differences in actual products, this ideal state may not always be achieved.

[0092] Figure 3B 、 Figure 3C The overlapping portion 22 and its vicinity are schematically enlarged and shown as an example of a non-ideal state. Figure 3B 、 3C , omitting Figure 3A Same instructions. Figure 3B In the example shown, the nozzle row 20C4 and the nozzle row 20C5 are aligned with each other in the nozzle arrangement direction D3. Figure 3A The ideal state is closer than the position relationship between each other. Figure 3C In the example shown, the nozzle row 20C4 and the nozzle row 20C5 are aligned with each other in the nozzle arrangement direction D3. Figure 3A The ideal state is far away from each other. Figure 3B 、 Figure 3CIn FIG. 2 , the nozzle # 46 of the nozzle row 20C4 and the nozzle # 2 of the nozzle row 20C5 forming the nozzle pair are displaced from each other in position when viewed from the relative movement direction D1 .

[0093] When printing using a print head 19 that alternately has a normal section and an overlapping section 22, a single nozzle 21 prints a single color of ink for a raster line through the normal section, while a pair of nozzles prints a single color of ink for a raster line through the overlapping section 22. A raster line is a linear image with its longitudinal direction oriented in the relative movement direction D1, and is a row of pixels arranged along the relative movement direction D1 in the print data. Printing a single color of ink for a raster line using a pair of nozzles is also called OL (Overlap) printing. In OL printing, the two nozzles 21 that form a nozzle pair are each used, for example, at a 50% utilization ratio.

[0094] In the print result reproduced on the medium 30, density differences tend to occur between the areas formed by the raster lines printed by the normal section and the areas formed by the raster lines printed by the nozzle pairs in the overlap section 22 in OL mode. This is because the number of nozzles used to print each raster line differs between the raster lines printed by the normal section and the raster lines printed by the overlap section 22 in OL mode. This difference affects various factors such as ink bleeding, drying, and line thickness, resulting in density differences. Such density differences are perceived by the user as uneven density.

[0095] In the nozzle arrangement direction D3, a boundary B1 (see Figure 6 ) is located within the range of the overlapping portion 22. In this specific example, in order to minimize the concentration difference between the printing result of the normal portion and the printing result of the overlapping portion 22, OL printing should not be performed in the overlapping portion 22 as much as possible. This can also be said to be to avoid using all n groups of nozzle pairs in OL printing. However, it is necessary to avoid the situation where a gap is generated in the first printing area AR1 of the first nozzle column and the second printing area AR2 of the second nozzle column in the width direction D2 due to not implementing OL printing. Therefore, first, according to the first test pattern without anti-flow dots, the use range of the first nozzle and the second nozzle is determined. Hereinafter, the test pattern is sometimes referred to as TP, and the first test pattern is sometimes referred to as the first TP.

[0096] Figure 4The flowchart schematically illustrates the nozzle usage range determination process performed by the control unit 11 according to the program 12. Here, steps S100 to S110 correspond to the first test pattern printing step ST1, and steps S120 to S130 correspond to the usage range determination step ST2. Below, "steps" are sometimes omitted, with step numbers indicated in parentheses. The nozzle usage range determination process begins when the control unit 110 receives a start instruction for the nozzle usage range determination process via the operation reception unit 14.

[0097] When the nozzle usage range determination process begins, the control unit 11 obtains the print data representing the first TP, i.e., the first TP print data (S100). When the first TP print data is stored in a storage location such as the storage unit 15 or a memory inside or outside the printing device 10, the control unit 11 can obtain the first TP print data from the storage location. In addition, the control unit 11 can also obtain the first TP print data by receiving the first TP print data from an external device via the communication I / F 16. Of course, the control unit 11 can also obtain the image data of the first TP from a storage location or an external device, and perform image processing such as resolution conversion processing, color conversion processing, and halftone processing on the image data to generate the first TP print data. The process of generating the first TP print data in this way is also included in the process of obtaining the first TP print data.

[0098] In this specific example, the print data provided by the control unit 11 to the print head 19, whether it is TP print data or print data expressing the image desired by the user, is provided on the basis of applying the offset correction between colors. Here, the offset correction between colors is briefly explained. For example, sometimes, Figure 2 The illustrated print heads 19C, 19M, 19Y, and 19K may have errors in their respective installation positions in the width direction D2. In this case, the amount of deviation in the width direction D2 of the C, M, and Y ink images printed by the print heads 19C, 19M, and 19Y is determined, using the K ink image printed by print head 19K as a reference. To eliminate the deviation of the C, M, and Y inks relative to K in the width direction D2, offset correction is applied to the print data provided to the print heads 19C, 19M, and 19Y, resulting in a print result on the medium 30 that compensates for the deviation between the CMYK colors. The print data, to which the offset correction is applied, determines which print head 19, nozzle array, and nozzle 21 position will be assigned the raster lines of each CMYK color.

[0099] After obtaining the first TP print data, the control unit 11 controls the transport unit 17 to start conveying the medium 30 and controls the print head 19 based on the first TP print data to print the first TP, which determines the usage range of the first and second nozzles in the overlapping portion 22, onto the medium 30 (S110). At this time, the control unit 11 sets the number of "specific nozzle pairs" in the overlapping portion 22, which use the first and second nozzles for ejecting the first liquid LQ1, to m, and prints the TP. Here, 0 ≤ m < n.

[0100] Figures 5A to 5C The first nozzle array and a portion of the second nozzle array in an ideal state in the print head 19C and the first TP 31 printed in S110 are schematically illustrated.

[0101] First, yes Figures 5A to 5C The first TP31 as a result of printing is a solid color image of one color ink. Figures 5A to 5C Ink C is used for printing. Figures 5A to 5C The first TP31 shown is not printed by the normal portion but by the overlapping portion 22. However, the first TP31 may include an area printed by the normal portion in addition to the area printed by the overlapping portion 22. Figures 5A to 5C In FIG, the numerical values ​​such as 0, +1, and -1 written in parentheses next to the symbol 31 refer to the adjustment values ​​of the use range of the first nozzle and the second nozzle used by the control unit 11 when printing the first TP 31. Figures 5A to 5C In FIG. 1 , “used nozzles” that eject ink for printing the first TP 31 among the nozzles 21 in the overlapping portion 22 are indicated by simple circles, and “unused nozzles” that do not eject ink for printing the first TP 31 are indicated by an x ​​mark in the circle.

[0102] like Figure 5A As shown, in the overlapping portion 22, nozzle numbers #45 to #47 of the nozzle array 20C4 are used nozzles, nozzle numbers #48 to #50 are unused nozzles, and nozzle numbers #1 to #3 of the nozzle array 20C5 are unused nozzles, and nozzle numbers #4 to #6 are used nozzles, to print the first TP31 (0) corresponding to the adjustment value = 0. When printing the first TP31 (0), the specific nozzle pair is 0 groups, that is, m = 0. Therefore, the raster line printed by the OL is not included in the first TP31 (0). In this way, as long as the adjustment value = 0 is as shown Figure 5A In such an ideal state, it can be said that the printing of the overlapping portion 22 is substantially the same as the printing of the normal portion.

[0103] like Figure 5BAs shown, in the overlapping portion 22, nozzle numbers #45 to #48 of the nozzle array 20C4 are used nozzles, nozzle numbers #49 and #50 are unused nozzles, and nozzle numbers #1 to #3 of the nozzle array 20C5 are unused nozzles, and nozzle numbers #4 to #6 are used nozzles, and the first TP31 (+1) corresponding to the adjustment value = +1 is printed. When printing the first TP31 (+1), the specific nozzle pair is a group, that is, m = 1. According to Figure 5B The nozzle #48 of the nozzle row 20C4 and the nozzle #4 of the nozzle row 20C5 correspond to a specific nozzle pair, and the raster line printed by the specific nozzle pair OL is included in the first TP31 (+1).

[0104] In general, OL printing is performed by distributing data of a plurality of pixels constituting a raster line to be printed by a nozzle pair at approximately 50% each to the two nozzles forming the nozzle pair. On the other hand, in TP printing in step S110, the control unit 11 distributes data of a plurality of pixels constituting a raster line to be printed by the specific nozzle pair at 100% each to the first nozzle and the second nozzle forming the specific nozzle pair. Figure 5B In the example of FIG. 2 , the same raster lines are printed overlappingly by the nozzle # 48 of the nozzle row 20C4 and the nozzle # 4 of the nozzle row 20C5 .

[0105] like Figure 5C As shown, in the overlapping portion 22, the nozzle numbers #45 and #46 of the nozzle array 20C4 are used nozzles, the nozzle numbers #47 to #50 are unused nozzles, and the nozzle numbers #1 to #3 of the nozzle array 20C5 are unused nozzles, and the nozzle numbers #4 to #6 are used nozzles, to print the first TP31 (-1) corresponding to the adjustment value = -1. When printing the first TP31 (-1), as with the first TP31 (0), m = 0, and the first TP31 (-1) does not include the raster lines printed by the OL. Moreover, a negative adjustment value means that there is a nozzle pair in which both the first nozzle and the second nozzle are unused nozzles, that is, an "unused nozzle pair". If the adjustment value = -1, the unused nozzle pair is a group. According to Figure 5C Nozzle #47 of nozzle row 20C4 and nozzle #3 of nozzle row 20C5 correspond to unused nozzle pairs. If there are unused nozzle pairs, the raster lines corresponding to the positions of the unused nozzle pairs in the print data are not printed.

[0106] In S110, the control unit 11 controls the print head 19 to print a plurality of first TPs 31 having different adjustment values, such as first TP 31 (0), first TP 31 (+1), and first TP 31 (-1), on the medium 30. Although not shown in the figure, the control unit 11 may also control the print head 19 to further print first TP 31 (+2) with an adjustment value of +2 and first TP 31 (-2) with an adjustment value of -2. When the adjustment value is +2, m = 2, and in addition to the nozzle pair of nozzle #48 of nozzle row 20C4 and nozzle #4 of nozzle row 20C5, the nozzle pair of nozzle #49 of nozzle row 20C4 and nozzle #5 of nozzle row 20C5 also becomes a specific nozzle pair. On the other hand, when the adjustment value = -2, m = 0. In addition to the nozzle pair of nozzle #47 in nozzle row 20C4 and nozzle #3 in nozzle row 20C5, the nozzle pair of nozzle #46 in nozzle row 20C4 and nozzle #2 in nozzle row 20C5 also becomes an unused nozzle pair. When the control unit 11 generates two or more specific nozzle pairs within the overlapping portion 22, it generates these multiple specific nozzle pairs continuously in the nozzle arrangement direction D3. Similarly, when the control unit 11 generates two or more unused nozzle pairs within the overlapping portion 22, it generates these multiple unused nozzle pairs continuously in the nozzle arrangement direction D3.

[0107] After the first TP is printed, the control unit 11 obtains the reading result of the first TP31 on the medium 30 (S120). In the case where the user evaluates the first TP31 visually, the control unit 11 only needs to obtain the result selected from the first TP31 (0), the first TP31 (+1), the first TP31 (-1), etc. through the operation receiving unit 14 as the reading result. Here, in the first TP31, the printing area of ​​the first nozzle column is referred to as the first printing area AR1, and the printing area of ​​the second nozzle column is referred to as the second printing area AR2. The user will evaluate the concentration of the "specific area 32" in the first TP31 from the "first printing position" of the printing position of the first nozzle located closest to the second printing area AR2 in the first printing area AR1 to the "second printing position" of the printing position of the second nozzle located closest to the first printing area AR1 in the second printing area AR2. In Figures 5A to 5C , the specific area 32 of the first TP 31 is shown surrounded by a dotted line. Note that a symbol such as a dotted line that indicates the specific area 32 in an easily understandable manner may be printed together with the first TP 31 in S110 or may not be printed.

[0108] Regarding first TP 31 (0), the printing position of nozzle #47 in the first printing area AR1 of nozzle array 20C4 is closest to the second printing area AR2 of nozzle array 20C5. Therefore, the printing position of nozzle #47 corresponds to the first printing position. Furthermore, the printing position of nozzle #4 in the second printing area AR2 of nozzle array 20C5 is closest to the first printing area AR1 of nozzle array 20C4. Therefore, the printing position of nozzle #4 corresponds to the second printing position. Therefore, the area in the width direction D2 of first TP 31 (0) from the first printing position of nozzle #47 of nozzle array 20C4 to the second printing position of nozzle #4 of nozzle array 20C5 corresponds to specific area 32.

[0109] Regarding the first TP31(+1), the printing position of nozzle #48 of nozzle array 20C4 on the medium 30 corresponds to the first printing position, and the printing position of nozzle #4 of nozzle array 20C5 on the medium 30 corresponds to the second printing position. Therefore, the area from the first printing position of nozzle #48 of nozzle array 20C4 to the second printing position of nozzle #4 of nozzle array 20C5 in the width direction D2 in the first TP31(+1) corresponds to the specific area 32. Figure 5B As shown, in an ideal state, the first printing position is the same as the second printing position, and therefore the specific area 32 becomes an area corresponding to one raster line.

[0110] Regarding the first TP 31(-1), the printing position of nozzle #46 of nozzle row 20C4 on the medium 30 corresponds to the first printing position, and the printing position of nozzle #4 of nozzle row 20C5 on the medium 30 corresponds to the second printing position. Therefore, the area in the width direction D2 in the first TP 31(-1) from the first printing position of nozzle #46 of nozzle row 20C4 to the second printing position of nozzle #4 of nozzle row 20C5 corresponds to the specific area 32.

[0111] When the above adjustment value becomes larger, raster lines printed by a specific nozzle pair are generated in the first TP 31, and therefore, the specific area 32 is likely to be generated. Figure 5B The "black streaks" shown in the example are "dark streaks" with a higher density than the adjacent colors in the first TP 31, that is, dark streaks, and are not limited to black. On the other hand, when the adjustment value becomes smaller, the first TP 31 prints through the overlapped portion 22 including the unused nozzle pair, so that the specific area 32 is more likely to produce the black streaks. Figure 5C"White stripes" as shown in the example. White stripes refer to "light stripes" with a lower concentration than the adjacent colors in the first TP31, that is, striped unevenness of bright colors, and are not limited to white. White stripes refer to light stripes in which the background color component of the medium 30 appears. However, depending on the position error between the nozzle rows in the width direction D2, the adjustment value for not generating stripes, the adjustment value for generating black stripes, and the adjustment value for generating white stripes will be different. Therefore, the control unit 11 performs a process of obtaining the reading result through the operation receiving unit 14. At this time, the user can visually evaluate the multiple first TP31 on the medium 30, select the first TP31 with the best image quality, and notify the control unit 11 of the selection result by operating the operation receiving unit 14. Good image quality means that white stripes and black stripes are not obvious. Even if the user does not clearly identify the specific area 32 within the first TP 31, the result is that the first TP 31 having strong black stripes or white stripes in the specific area 32 is not selected, and the first TP 31 having no black stripes or white stripes or inconspicuous black stripes or white stripes in the specific area 32 is selected. Therefore, it can be interpreted that the user has read the specific area 32.

[0112] Identification information such as a number, name, or adjustment value may also be printed on each first TP31 with a different adjustment value to facilitate user selection of the first TP31. The user simply inputs the identification information of the selected first TP31 through the operation reception unit 14 and notifies the control unit 11. The process of obtaining the result of the user's selection of the first TP31 corresponds to obtaining the result of reading the first TP31 in S120. Alternatively, the first TP31 may be read not by the user visually but by a reading device (not shown), such as a scanner or colorimeter, with the read image data or colorimetric value, which is the result of the reading, transmitted from the reading device to the printing device 10 via the communication interface 16. That is, in S120, the control unit 11 may obtain the result of reading the first TP31 from the reading device.

[0113] After obtaining the reading result, the control unit 11 determines the use range of the first nozzle and the use range of the second nozzle based on the reading result (S130). When the control unit 11 obtains the selection result of the first TP31 from the user, it determines the use range to be used when printing the first TP31 selected by the user. For example, if the user selects the first TP31 (+1), then Figure 5BAs shown, the control unit 11 determines the range of nozzle numbers #45 to #48 of nozzle row 20C4 in the overlapping portion 22 as the usage range of the first nozzles in the overlapping portion 22, and determines the range of nozzle numbers #4 to #6 of nozzle row 20C5 in the overlapping portion 22 as the usage range of the second nozzles in the overlapping portion 22. In this case, the specific nozzle pair used for OL printing in the overlapping portion 22 constitutes a set. After obtaining read image data or colorimetric values ​​as the reading results of the first TP31 from the reading device, the control unit 11 analyzes the reading results for each first TP31 and evaluates the presence and degree of black or white streaks in the specific area 32 based on predetermined evaluation criteria. The control unit 11 then selects the first TP31 with the best image quality. In other words, the control unit 11 can execute the user's selection of the first TP31 as described above, according to the program 12. Then, for the overlapping portion 22, the control unit 11 determines the usage ranges of the first nozzles and the second nozzles as the usage ranges to be used when printing on the selected first TP31. In this way, the control unit 11 determines the use range of the first nozzle and the use range of the second nozzle based on the density of the specific area 32 of the first TP 31 printed on the medium 30 in S120 and S130 .

[0114] exist Figures 5A to 5C In the example shown, the usage range of the nozzles 21 of nozzle row 20C5, which serves as the second nozzle row, remains fixed regardless of the adjustment value, while the usage range of the nozzles 21 of nozzle row 20C4, which serves as the first nozzle row, changes in accordance with the adjustment value in the overlapping portion 22. Of course, the control unit 11 may also fix the usage range of the nozzles 21 of the first nozzle row during printing at the first TP 31 and change the usage range of the nozzles 21 of the second nozzle row according to the adjustment value. In this way, when only the usage range of the nozzles 21 of either the first or second nozzle row is changed in the overlapping portion 22, the usage ranges of the first and second nozzles are determined by determining the usage range of the nozzles 21 of the nozzle row with the variable usage range. Of course, the control unit 11 may also change the usage range of the nozzles 21 of the first and second nozzle rows according to the adjustment value during printing at the first TP 31.

[0115] If the control unit 11 determines the use range of the first nozzle and the second nozzle, it saves the determined content and uses Figure 4 The nozzle usage range determination process shown is completed. Determining the usage range also determines the unused range of the nozzles 21. For the normal part, all nozzles 21 are in the usage range, so there is no need to re-determine the usage range and unused range. The control unit 11 executes the following for all overlapping parts 22 of the print heads 19C, 19M, 19Y, and 19K: Figure 4In the nozzle use range determination process shown, the use ranges of the first nozzle and the second nozzle are determined for each overlapping portion 22 .

[0116] Thereafter, when executing printing in response to a user instruction, the control unit 11 performs printing using the ranges determined as described above as the usage ranges of the first nozzle and the second nozzle in the overlapping portion 22 .

[0117] As described above, the combination of the medium 30 and the liquid LQ0 used in printing can minimize the number of specific nozzle pairs performing OL printing in the overlap portion 22, thereby preventing uneven density such as black or white streaks from occurring in the printed result of the overlap portion 22, which could degrade image quality. Consequently, the issue of a significant difference in density between the area printed by the normal portion and the area printed by the overlap portion 22 with OL printing is also resolved.

[0118] However, it is known that if the combination of the medium 30 and the liquid LQ0 is changed, even if the usage range of the first nozzle and the second nozzle is determined based on the concentration of the specific area 32 of the first TP 31, light streaks will be generated between the nozzle arrays along the relative movement direction D3 of the medium 30. In particular, when the wettability of the liquid LQ0 to the medium 30 is low, such as when UV (ultraviolet) ink or resin ink is ejected onto the medium 30, or when ink is ejected onto a resin medium, the wettability of the liquid LQ0 to the medium 30 is low. Figure 14 As shown in the example, light-colored streaks 50 are easily generated. The wettability of liquid LQ0 with respect to medium 30 can be quantified by the contact angle of a droplet placed on the medium. A larger contact angle indicates lower wettability, while a smaller contact angle indicates higher wettability. Lower wettability indicates a stronger repulsion of liquid LQ0 from medium 30, while higher wettability indicates a weaker repulsion of liquid LQ0 from medium 30.

[0119] Figure 14 The behavior of the first liquid LQ1 on the medium 30 is schematically illustrated in the case where the wettability of the liquid LQ0 with respect to the medium 30 is low. Figure 14 Schematically shows the main part of the print head 19 having the first nozzle array 201 on the upstream side S1 and the second nozzle array 202 on the downstream side S2 and the Figure 6 The main part of the printed image 45 without the anti-flow dot DT1 is shown in FIG. Figure 14 The lower part of FIG is schematically shown as the printing data 40 for causing the printing head 19 to eject the first liquid LQ1. Figure 14 The nozzle arrays 201 and 202 are shown in an ideal state. However, when the nozzle arrays 201 and 202 are not in an ideal state, Figure 4The first liquid LQ1 is ejected within the usage range determined in the nozzle usage range determination process.

[0120] As described above, in the first nozzle array 201, the plurality of first nozzles 211 are arranged in the nozzle arrangement direction D3, and in the second nozzle array 202, the plurality of second nozzles 212 are arranged in the nozzle arrangement direction D3. The usage range of the two nozzles 211 and 212 in the overlapping portion 22 is determined by the first TP31. In the nozzle arrangement direction D3, the boundary B1 between the first printing area AR1 of the first nozzle array 201 and the second printing area AR2 of the second nozzle array 202 is located within the overlapping portion 22.

[0121] Here, if Figure 14 As shown in the lower part of , it is assumed that the printing data 40 indicates that the first liquid LQ1 is seamlessly ejected from the first printing area AR1 to the second printing area AR2. When the control unit 11 controls the drive of the print head 19 according to the printing data 40, first, the first liquid LQ1 ejected from the first nozzle column 201 on the upstream side S1 is sprayed onto the medium 30, and after a predetermined period, the first liquid LQ1 ejected from the second nozzle column 202 on the downstream side S2 is sprayed onto the medium 30. In the case where the wettability of the liquid LQ0 relative to the medium 30 is low, the result that the first liquid LQ1 on the first printing area AR1 is ejected earlier than the first liquid LQ1 on the second printing area AR2 will cause the liquid to flow in a convergent manner in the first printing area AR1. Figure 14 In the figure, the landing range of the first liquid LQ1 is indicated by a two-dot chain line outside the first printing area AR1. As indicated by the arrow within the two-dot chain line, the first liquid LQ1 in the first printing area AR1 flows away from the boundary B1. Therefore, the first liquid LQ1 that lands later on the second printing area AR2 does not connect with the first liquid LQ1 in the first printing area AR1, resulting in light-colored streaks 50 between the nozzle rows along the relative movement direction D1 of the medium 30.

[0122] In this specific example, if Figure 6 As shown, the control unit 11 controls the first nozzles 211 included in the first nozzle array 201 on the upstream side S1 to function as the anti-flow dot forming nozzles NZ2 to form anti-flow dots DT1 in the second printing area AR2.

[0123] Figure 6 The main parts of the print head 19 and the main parts of the printed image 45 are shown schematically. Figure 6The lower part of FIG schematically shows the printing data 41 for causing the first nozzle array 201 to eject the first liquid LQ1 and the printing data 42 for causing the second nozzle array 202 to eject the first liquid LQ1. Figure 14 In FIG. 1 , the nozzle arrays 201 and 202 are shown in an ideal state. However, when the nozzle arrays 201 and 202 are not in an ideal state, the nozzle arrays 201 and 202 are shown in FIG. Figure 4 The nozzle usage range determines the usage range determined in the treatment. Figure 7 The intervals between the anti-flow points DT1 in the relative movement direction D1 are schematically illustrated.

[0124] Figure 6 The nozzle #48 of the first nozzle array 201 shown is located in the second printing area AR2 and is located at the end of the second printing area AR2 on the first printing area AR1 side in the nozzle arrangement direction D3. Figure 6 FIG. 2 shows a case where the nozzle #48 of the first nozzle array 201 is not an unused nozzle but is used as the anti-flow dot forming nozzle NZ2 for forming the anti-flow dot DT1. In addition, the nozzles #47 (in the first printing area AR1) of the plurality of first nozzles 211 are used. Figure 6 The nozzles #42 to #47 in the figure are called normal nozzles NZ1. Figure 6 The plurality of first nozzles 211 shown include a plurality of normal nozzles NZ1 located in the first printing area AR1 and an anti-flow point forming nozzle NZ2 located at the end portion on the first printing area AR1 side in the second printing area AR2. The control unit 11 is capable of accepting a setting of whether to form an anti-flow point DT1 via the operation accepting unit 14. Here, it is assumed that the aforementioned setting indicates the formation of the anti-flow point DT1. In this case, the control unit 11 causes the print head 19 to form a plurality of anti-flow points DT1 that are not adjacent to each other in the relative movement direction D1 by ejecting the first liquid LQ1 from the anti-flow point forming nozzle NZ2 toward the medium 30 during printing.

[0125] In the printing data 40, as Figure 7As shown, the pixel PX1 is set as the unit for configuring the points including the anti-flow point DT1. A pixel is the smallest element constituting an image to which colors can be independently assigned. The pixel PX1 refers to a unit area that divides the formation position of each point for a certain color, such as C. In other words, for a certain color, each pixel PX1 is assigned whether to configure a point. That a plurality of anti-flow points DT1 are not adjacent to each other in the relative movement direction D1 means that anti-flow points DT1 are configured on both sides of the pixels PX1 that are not adjacent in the relative movement direction D1. When the ratio of the number of points to the number of pixels is referred to as a recording rate, when a plurality of anti-flow points DT1 are not adjacent to each other in the relative movement direction D1, the recording rate of the anti-flow points DT1 in the relative movement direction D1 becomes 50% or less within a range greater than 0%.

[0126] like Figure 7 As shown, the spacing of the anti-flow dots DT1 in the relative movement direction D1 can be set to various values, such as two dots, equivalent to 50% of the maximum recording rate, three dots, equivalent to 33% of the maximum recording rate, or four dots, equivalent to 25% of the maximum recording rate. Furthermore, if the spacing of the anti-flow dots DT1 in a printed image with a recording rate of 100% is two dots, then the anti-flow dots DT1 are formed at every other dot, i.e., every other pixel, in the relative movement direction D1. If the recording rate of the printed image is less than 100%, for example, if the anti-flow dots DT1 are formed at locations where normal dots are formed in the printed image, the anti-flow dots DT1 are formed at those locations and not at locations where dots are not formed in the printed image. Therefore, the recording rate of the anti-flow dots DT1 decreases in accordance with the recording rate of the printed image.

[0127] The intervals between the plurality of anti-flow points DT1 are preferably substantially equal. Figure 7, the case where the intervals of the anti-flow dots DT1 are equally spaced is shown. The anti-flow dots DT1 are sometimes arranged in units of pixels PX1, and therefore, a little bit of variation occurs depending on the recording rate of the anti-flow dots DT1. "Approximately equally spaced" means that the variation of the intervals of the anti-flow dots DT1 is less than a little bit. For example, when the recording rate of the anti-flow dots DT1 is 40%, the intervals of the anti-flow dots DT1 that are approximately equally spaced become two dots or three dots. When the recording rate of the anti-flow dots DT1 is 30%, the intervals of the anti-flow dots DT1 that are approximately equally spaced become three dots or four dots. It is preferred that the intervals of the anti-flow dots DT1 are approximately equally spaced because, when there is a deviation exceeding approximately equal spacing in the intervals of a plurality of anti-flow dots DT1, the image quality of the printed image 45 may be reduced. Sometimes, the first liquid LQ1 of the first printing area AR1 and the first liquid LQ1 of the second printing area AR2 are connected at the narrow distance described above, but are disconnected at the wide distance described above. In this case, the printed image 45 is disturbed at the boundary B1 between the first printing area AR1 and the second printing area AR2, thereby reducing the quality of the printed image 45.

[0128] exist Figure 6 At the bottom of the , the printing data 40 is shown as having a dot recording rate of 100%. The control unit 11 assigns dot data for forming dots on the medium 30 to each nozzle 21 based on the printing data 40, and in addition to these dot data, anti-flow dot data is also assigned to the anti-flow dot forming nozzle NZ2. The dot data is multi-value data indicating the formation state of the dot, such as binary data indicating whether or not a dot is formed. The binary dot data can be set to, for example, data of "1" indicating that a dot is formed or "0" indicating that no dot is formed. The multi-value dot data can be set to, for example, 4-value data of "3" indicating that a large dot is formed, "2" indicating that a medium dot is formed, "1" indicating that a small dot is formed, or "0" indicating that no dot is formed. The anti-flow dot data is dot data for forming the anti-flow dot DT1 at the end portion on the first printing area AR1 side in the second printing area AR2 on the medium 30.

[0129] Figure 6 The print data 42 shown is for nozzles #4 to #6 allocated to the second nozzle array 202 in order to form dots in the second print area AR2. Figure 6 The data in the figure are #4 to #9). Figure 6 The print data 41 shown is for the nozzles #47 (in the first nozzle array 201) allocated to form dots in the first print area AR1. Figure 6The dot data 41 is the dot data obtained by adding the anti-flow dot data to the dot data of #42 to #47 in the second printing area AR2. In order to form the anti-flow dot DT1 on the second printing area AR2 instead of the first printing area AR1, the anti-flow dot data is assigned to the nozzle #48 of the first nozzle column 201. Therefore, the printing data 41 is the dot data obtained by combining the dot data assigned to the normal nozzle NZ1 located in the first printing area AR1 and the anti-flow dot data assigned to the anti-flow dot forming nozzle NZ2 located in the second printing area AR2. Therefore, in terms of data, at the end on the first printing area AR1 side in the second printing area AR2, the first liquid LQ1 ejected from the nozzle #4 of the second nozzle column 202 overlaps with the first liquid LQ1 ejected from the anti-flow dot forming nozzle NZ2.

[0130] In the case where the wettability of the liquid LQ0 to the medium 30 is low, if there is no anti-flow point DT1, Figure 14 As shown, the first liquid LQ1, which lands on the first printing area AR1 before the second printing area AR2, flows in a converged manner on the medium 30, resulting in light streaks 50. Here, when the first liquid LQ1 is ejected from the anti-flow point-forming nozzle NZ2 located in the second printing area AR2 in the first nozzle array 201 so that the dots are continuously ejected in the relative movement direction D1, dark streaks such as black streaks are generated. By making the multiple anti-flow points DT1 non-adjacent in the relative movement direction D1, the first liquid LQ1 in the first printing area AR1 and the first liquid LQ1 in the second printing area AR2 are appropriately connected, thus suppressing the light streaks 50.

[0131] Due to the above-described effects, this specific example can suppress the occurrence of light-colored streaks along the relative movement direction D1 of the medium 30 between the nozzle rows due to the flow of dots on the medium 30 .

[0132] like Figure 8 As shown, the size of the anti-flow point DT1 can also be set to various sizes, for example, a large point, a medium point, a small point, etc. Figure 8 The dimensions of the anti-flow point DT1 are schematically illustrated.

[0133] like Figure 9 As shown, the number of the anti-flow point forming nozzles NZ2 can also be set to various numbers, for example, one nozzle, two nozzles, three nozzles, etc. Figure 9The number of anti-flow dot forming nozzles NZ2 is schematically illustrated. The anti-flow dot forming nozzles NZ2 are located in a position in the first nozzle array 201 that is continuous with the arrangement of the normal nozzles NZ1. When the anti-flow dot forming nozzle NZ2 is a single nozzle, the anti-flow dot forming nozzle NZ2 is adjacent to the normal nozzle NZ1 in the width direction D2. When the anti-flow dot forming nozzles NZ2 are two nozzles, the anti-flow dot forming nozzle NZ2 is a combination of a nozzle adjacent to the normal nozzle NZ1 in the width direction D2 and a nozzle adjacent to the nozzle (not the normal nozzle NZ1).

[0134] Figure 10 The adjustment process performed by the control unit 11 according to the program 12 is schematically illustrated by the flowchart. Figure 4 The adjustment process is performed based on the nozzle usage range determination process shown. Here, S204 corresponds to the size setting acceptance process ST4. S206 corresponds to the second test pattern printing process ST5 and the anti-flow dot formation process ST3. This is to form a second TP35 containing an anti-flow dot DT1 when printing the first TP31 without using the anti-flow dot forming nozzle NZ2, resulting in a streak 50 formed by the flow of the first liquid LQ1 between the printing areas AR1 and AR2. S208 to S210 correspond to the interval determination process ST6. Figure 11 The main parts of the print head 19 and the second test pattern 35 are schematically illustrated. Hereinafter, the second test pattern may be simply referred to as a second TP.

[0135] The following describes the process of determining the formation conditions of the anti-flow dot DT1 for a certain overlapping portion 22 included in the print head 19C. Of course, the nozzle use range determination process can be performed for each of the multiple overlapping portions 22 included in the print head 19C, or for the print heads 19M, 19Y, and 19K.

[0136] The adjustment process can be started when the control unit 110 receives an instruction to start the adjustment process via the operation receiving unit 14. Alternatively, the adjustment process can be started when the control unit 11 detects a change in at least one of the type of the medium 30 and the type of the first liquid LQ1. By executing the second TP formation process in S208, the printing device 10 forms the second TP 35 when at least one of the type of the medium 30 and the type of the first liquid LQ1 has changed.

[0137] The wettability of liquid LQ0 with respect to medium 30 depends on the combination of the type of medium 30 and the type of liquid LQ0. Therefore, if at least one of the types of medium 30 and first liquid LQ1 changes, the degree of dot flow on medium 30 may change. If a second TP35 is formed due to a change in at least one of the types of medium 30 and first liquid LQ1, light streaks 50 caused by dot flow on medium 30 can be suppressed according to the second TP35.

[0138] When the adjustment process begins, the control unit 11 causes the display unit 13 to display a user interface screen (not shown) and accepts a selection via the operation accepting unit 14 regarding whether to form the anti-flow dot DT1 (S202). For example, if light streaks 50 are present on the printed image 45 (including the first TP 31) formed on the medium 30 according to the determined usage range, the user can operate the operation accepting unit 14 to form the anti-flow dot DT1. If light streaks 50 are not present on the printed image 45, or if they are present, there is no problem, the user can operate the operation accepting unit 14 to not form the anti-flow dot DT1. If the user has selected not to form the anti-flow dot DT1, the control unit 11 terminates the adjustment process.

[0139] When the formation of the anti-flow dot DT1 is selected, the control unit 11 accepts the setting operation of the size of the anti-flow dot DT1, etc. via the operation receiving unit 14 (S204). Based on this, the control unit 11 obtains the original printing data expressing the second TP35, generates the printing data 40 from the original printing data according to the settings of the size of the anti-flow dot DT1, and forms the second TP35 including the anti-flow dot DT1 on the medium 30 (S206). When the original printing data is stored in a storage location such as the storage unit 15 or a memory inside or outside the printing device 10, the control unit 11 can obtain the original printing data from the storage location. In addition, the control unit 11 can also obtain the original printing data by receiving the original printing data from an external device via the communication I / F 16. Of course, the control unit 11 can also obtain the image data of the second TP from a storage location or an external device and perform image processing such as resolution conversion processing, color conversion processing, halftoning processing, etc. on the image data to generate the original printing data. The process of generating the original printing data in this way is also included in the process of obtaining the original printing data.

[0140] like Figure 11 As shown, the second TP 35 is formed including the anti-flow point DT1 by the first liquid LQ1 ejected from the first nozzle row 201 and the second nozzle row 202 toward the medium 30 . Figure 11The second TP35 shown includes a plurality of independent patterns 36 in which the intervals between the anti-flow points DT1 in the relative moving direction D1 are changed. For example, the independent pattern 36a includes Figure 7 The independent pattern 36b includes a plurality of anti-flow dots DT1 with a dot spacing of two dots. Figure 7 The independent pattern 36c includes a plurality of anti-flow dots DT1 with a dot spacing of three dots. Figure 7 The four points shown are spaced apart from each other to form a plurality of anti-flow points DT1. Figure 11 , a case where a dot recording rate of (50%) representing the independent pattern 36 a , a dot recording rate of (33%) representing the independent pattern 36 b , and a dot recording rate of (25%) representing the independent pattern 36 a are also formed on the medium 30 is shown.

[0141] For example, Figure 8 As shown, when there are large dots, medium dots, and small dots as dot sizes, the user can set the size of the anti-flow dot DT1 to be large, medium, or small on the operation receiving unit 14. When the setting operation of the large dot is accepted, the control unit 11 causes the print head 19 to form the large dot. Figure 11 The plurality of anti-flow dots DT1 of the second TP35 shown are shown. When the small dot setting operation is received, the control unit 11 causes the print head 19 to form the plurality of anti-flow dots DT1 of the second TP35 using the small dots. For example, if light streaks 50 are visible even when the plurality of anti-flow dots DT1 are formed using the small dots, the size of the anti-flow dots DT1 can be increased. When the size of the anti-flow dots DT1 is increased, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases, thereby reducing the light streaks 50. Consequently, streaks along the relative movement direction D1 between the nozzle arrays can be further appropriately suppressed.

[0142] When stripes 50 formed by the flow of the first liquid LQ1 are generated between the printing areas AR1 and AR2 during printing based on the usage range of the first TP31 in the above manner, the control unit 11 forms a plurality of anti-flow points DT1 that are not adjacent to each other in the relative movement direction D1 by ejecting the first liquid LQ1 from the anti-flow point forming nozzle NZ2 toward the medium 30.

[0143] In S204, the control unit 11 may also accept the setting operation of the interval between the anti-flow points DT1 in the relative moving direction D1 via the operation accepting unit 14. Figure 7 When the two-dot setting operation is performed as shown, the control unit 11 can make the printing head 19 form at least Figure 11 The second TP35 of the independent pattern 36a is shown. Figure 7When the four-dot setting operation is performed, the control unit 11 can make the printing head 19 form at least Figure 11 The second TP35 of the independent pattern 36c is shown. For example, if light streaks 50 are still visible even if a plurality of anti-flow dots DT1 are formed at intervals of four dots, the intervals between the anti-flow dots DT1 can be reduced. When the intervals between the anti-flow dots DT1 are reduced, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases, thereby reducing the light streaks 50. Consequently, streaks along the relative movement direction D1 between the nozzle arrays are further appropriately suppressed.

[0144] In S204, the control unit 11 may also accept the setting operation of the number of anti-flow point forming nozzles NZ2 via the operation accepting unit 14. Figure 9 When the setting operation of one nozzle is performed, the control unit 11 causes the printing head 19 to form a plurality of anti-flow dots DT1 of the second TP35 in such a manner that one is arranged in the width direction D2. Figure 9 When operating to set three nozzles as shown, the control unit 11 causes the print head 19 to form multiple anti-flow dots DT1 in the second TP35, arranging three nozzles in the width direction D2. For example, if light streaks 50 are still visible even when a single anti-flow dot-forming nozzle NZ2 is used, the number of anti-flow dot-forming nozzles NZ2 can be increased. Increasing the number of anti-flow dot-forming nozzles NZ2 increases the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side, thereby reducing the light streaks 50. Consequently, streaks along the relative movement direction D1 between the nozzle arrays are further appropriately suppressed.

[0145] After printing the second TP 35 , the control unit 11 obtains the reading result of the second TP 35 on the medium 30 ( S208 ). When the user visually evaluates the second TP 35 , the control unit 11 may obtain the result selected from the independent patterns 36 a to 36 c via the operation receiving unit 14 as the reading result. Figure 11 The illustrated independent pattern 36 a has a plurality of anti-flow dots DT1 spaced two dots apart, thereby generating stripes that are darker than the surrounding stripes along the relative movement direction D1 . Figure 11 The illustrated independent pattern 36 c has stripes that are lighter than the surrounding stripes along the relative movement direction D1 due to a plurality of anti-flow dots DT1 spaced apart by four dots. Figure 11The independent pattern 36b shown has multiple anti-flow dots DT1 spaced at intervals of three dots, and no stripes of different shades are seen along the relative moving direction D1. Therefore, the user can select the independent pattern 36b corresponding to the best image quality (33%) and operate the operation receiving unit 14 to notify the control unit 11 of the selection result. The process of obtaining the selection result of the second TP35 from the user is equivalent to obtaining the reading result of the second TP35 in S208. In addition, the second TP35 may be read not by the user visually, but by a reading device not shown in the figure, such as a scanner or a colorimeter, and the read image data or colorimetric value as the reading result is sent from the reading device to the printing device 10 via the communication I / F16 in S208. That is, in S208, it may also be set that the control unit 11 obtains the reading result of the second TP35 from the reading device.

[0146] After obtaining the reading result, the control unit 11 determines the formation conditions of the anti-flow dots DT1 based on the reading result and saves the determination content (S210). When the control unit 11 obtains the selection result of the second TP35 from the user, it determines the intervals between the anti-flow dots DT1 used in forming the printed image 45 to be the intervals corresponding to the selection result. Thereafter, the execution Figure 13 The illustrated printing control process can be said to determine the intervals between the anti-flow dots DT1 used in the anti-flow dot forming process ST3 based on the second TP35. For example, if the user selects the independent pattern 36b, the control unit 11 determines the intervals between the anti-flow dots DT1 used in forming the printed image 45 to be three dots. The control unit 11 can also execute the process for all overlapping portions 22 of the print heads 19C, 19M, 19Y, and 19K. Figure 10 The adjustment process shown in FIG. 1 is performed, and the formation conditions of the anti-flow dot DT1 are determined for each overlapping portion 22. Thereafter, when the control unit 11 performs printing according to the user's instructions, etc., Figure 12 The illustrated printing control process forms the anti-flow dot DT1 under the aforementioned formation conditions.

[0147] like Figure 11 As shown, when the intervals between the anti-flow dots DT1 are narrowed, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases. While light streaks are visible, as in the independent pattern 36c, narrowing the intervals between the anti-flow dots DT1, as in the independent pattern 36b, reduces the light streaks. Consequently, streaks along the relative movement direction D1 between the nozzle arrays are further appropriately suppressed.

[0148] Figure 12The flow chart schematically illustrates the printing control process executed by the control unit 11 according to the program 12. Figure 10 The print control process is executed based on the adjustment process shown. Here, S306 to S308 correspond to the anti-flow dot forming step ST3. The print control process starts when the control unit 110 receives an instruction to start the print control process via the operation receiving unit 14.

[0149] When the print control process starts, the control unit 11 obtains print data 40 representing an image (S302). This print data 40 is not limited to data with a dot recording rate of 100%. It can also include data representing various images with a dot recording rate of less than 100%, such as natural paintings or photographs used by users to decorate their rooms or for sale, and document images such as line drawings used for presentations and displayed to others.

[0150] After acquiring the print data 40, the control unit 11 allocates dot data to each nozzle 21 used in printing based on the print data 40 (S304). Figure 6 As shown, the control unit 11 distributes dot data for the first printing area AR1 to nozzles #47 of the first nozzle row 201, and distributes dot data for the second printing area AR2, i.e., print data 42, to nozzles #4 through #5 of the second nozzle row 202. At this point, print data 42 for the second nozzle row 202 is generated.

[0151] The control unit 11 then assigns the anti-flow dot data to the anti-flow dot forming nozzle NZ2 based on the print data 40 (S306). For example, if the print data 42 indicates that the position of a normal dot is assigned to the end of the second print area AR2 on the first print area AR1 side as the allocation position of the anti-flow dot DT1, the control unit 11 assigns the dot to that allocation position. In this manner, the print data 41 for the first nozzle array 201 is generated.

[0152] Finally, the control unit 11 causes the print head 19 to eject liquid droplets LQ0 according to the print data 40, thereby forming a print image 45 on the medium 30 (S308). Focusing on the print head 19C, the control unit 11 causes the first liquid LQ1 of C to be ejected from the first nozzle array 201 according to the print data 41, and causes the first liquid LQ1 of C to be ejected from the second nozzle array 202 according to the print data 42. At this time, at the end of the second print area AR2 on the first print area AR1 side, the first liquid LQ1 of C is ejected from the flow prevention dot forming nozzle NZ2 toward the medium 30, forming a plurality of non-adjacent flow prevention dots DT1 in the relative movement direction D1.

[0153] As described above, when the streak 50 caused by the flow of the first liquid LQ1 occurs between the print areas AR1 and AR2 during printing based on the use range of the first TP 31 , the control unit 11 forms the plurality of flow prevention dots DT1 .

[0154] As described above, the first liquid LQ1 is ejected from the anti-flow point forming nozzle NZ2 of the first nozzle array 201 facing the first printing area AR1 toward the second printing area AR2 to form the anti-flow point DT1, thereby suppressing the flow. Figure 14 The light streaks 50 shown in the figure are not adjacent to each other in the relative movement direction D1. This ensures that the first liquid LQ1 in the first printing area AR1 and the first liquid LQ1 in the second printing area AR2 are appropriately connected, thus suppressing the generation of dark streaks. Therefore, this specific example can suppress the generation of light streaks along the relative movement direction D1 of the medium 30 between the nozzle arrays due to the flow of dots on the medium 30.

[0155] (3) Modification:

[0156] Various modifications can be made to the present invention.

[0157] The printing device 10 is not limited to a line-type printing device, but may also be a serial-type printing device. For example, a print head 19 may be mounted on a carriage movable in the main scanning direction, and the print head 19 may include a first nozzle array 201 and a second nozzle array 202. In this case, the relative movement direction D1 is along the main scanning direction, and the transport unit 17 does not move the medium 30 but instead moves the print head 19 in a direction opposite to the relative movement direction D1. Therefore, the transport unit 17 moves the medium 30 relative to the print head 19 in the relative movement direction D1, which intersects the nozzle arrangement direction D3.

[0158] Figure 11 The second TP 35 shown includes a plurality of independent patterns 36 in which the intervals between the anti-flow points DT1 in the relative moving direction D1 are changed, but the second TP is not limited to Figure 11 For example, when the second TP includes a plurality of independent patterns with different sizes of the anti-flow dot DT1, the control unit 11 can determine the size of the anti-flow dot DT1 used in the anti-flow dot forming step ST3. When the second TP includes a plurality of independent patterns with different numbers of the anti-flow dot forming nozzles NZ2, the control unit 11 can determine the number of the anti-flow dot forming nozzles NZ2 used in the anti-flow dot forming step ST3.

[0159] like Figure 13As illustrated, the control unit 11 may also execute control to change the anti-flow dot forming nozzle NZ2 to the normal nozzle NZ1. This is because the appropriate use ranges of the first nozzle 211 and the second nozzle 212 may change due to changes in the state of the nozzle 21 or the environment.

[0160] Figure 13 Another example of the print control process executed by the control unit 11 according to the program 12 is schematically illustrated by a flowchart. This print control process is also started when the control unit 110 receives an instruction to start the print control process via the operation receiving unit 14. Figure 13 The process also shows a UI (user interface) screen 500 and the role of the nozzle 21 during printing.

[0161] When the printing control process starts, the control unit 11 displays the UI screen 500 on the display unit 13 (S402). The UI screen 500 has a selection item 501 for forming the anti-flow dot DT1 by the anti-flow dot forming nozzle NZ2, a selection item 502 for changing the anti-flow dot forming nozzle NZ2 to the normal nozzle NZ1, a confirmation button not shown, etc. The operation acceptance unit 14 can accept an operation of selecting either of the items 501 and 502. The user can select either of the selection items 501 and 502 by operating either of the selection items 501 and 502 and operating the confirmation button. When the selection item 502 is selected, the operation acceptance unit 14 accepts the change operation from the anti-flow dot forming nozzle NZ2 to the normal nozzle NZ1. The control unit 11 accepts the selection operation of either of the selection items 501 and 502 via the operation acceptance unit 14.

[0162] When the confirmation button is operated, the control unit 11 branches the processing according to the selection operation of the selection items 501 and 502 (S404). When the control unit 11 accepts the selection operation of the selection item 501, as shown in the flow, during printing, the anti-flow dot forming nozzle NZ2 is used to form a plurality of anti-flow dots DT1 that are not adjacent to each other in the relative movement direction D1 (S406). On the other hand, when the control unit 11 accepts the selection operation of the selection item 502, as shown in the flow, the anti-flow dot forming nozzle NZ2 is changed to the normal nozzle NZ1, so that the print head 19 forms normal dots (S408). Therefore, when the change operation from the anti-flow dot forming nozzle NZ2 to the normal nozzle NZ1 is accepted, the control unit 11 changes the anti-flow dot forming nozzle NZ2 to the normal nozzle NZ1 and controls the ejection of the liquid LQ0 of the print head 19.

[0163] When the anti-flow dot forming nozzle NZ2 is replaced with the normal nozzle NZ1, the amount of first liquid LQ1 ejected from the first nozzle array 201 toward the end of the second printing area AR2 on the first printing area AR1 side increases. This can reduce the light streaks that are still visible even after the anti-flow dot DT1 is formed.

[0164] (4) Summary:

[0165] As described above, the present invention can provide a structure capable of suppressing the generation of light-colored streaks between nozzle rows along the relative movement direction of the medium due to the flow of dots on the medium in various ways. Of course, even in a method formed using the structural elements described in the technical solution, the basic functions and effects described above can be achieved.

[0166] Furthermore, various configurations disclosed in the above examples may be replaced or combined with each other, or various configurations disclosed in known technologies and the above examples may be replaced or combined with each other. The present invention also includes these configurations.

[0167] Explanation of symbols

[0168] 10…printing device; 11…control unit; 12…program; 13…display unit; 14…operation receiving unit; 15…storage unit; 16…communication I / F; 17…transfer unit; 19…print head; 20C, 20C1, 20C2, 20C3, 20C4, 20C5, 20M, 20Y, 20K…nozzle array; 21…nozzle; 22…overlapping portion; 30…medium; 31…first test pattern; 32…specific area; 35…second test pattern; 36, 36a to 36c…independent pattern; 40, 41, 42…printing data; 45…printing image; 50…stripes; 201…first nozzle array; 202…second nozzle array; 211…first One nozzle; 212…the second nozzle; 500…the user interface screen; AR1…the first printing area; AR2…the second printing area; B1…the boundary; D1…the relative movement direction; D2…the width direction; D3…the nozzle arrangement direction; DT1…the anti-flow dot; LQ0…the liquid; LQ1…the first liquid; NZ1…the normal nozzle; NZ2…the anti-flow dot forming nozzle; PX1…the pixel; S1…the upstream side; S2…the downstream side; ST1…the first test pattern printing process; ST2…the usage range determination process; ST3…the anti-flow dot forming process; ST4…the size setting acceptance process; ST5…the second test pattern printing process; ST6…the interval determination process.

Claims

1. A printing device comprising: a print head having a first nozzle array formed by a plurality of first nozzles arranged in a predetermined nozzle array direction and capable of ejecting a first liquid onto a medium, and a second nozzle array formed by a plurality of second nozzles arranged in the nozzle array direction and capable of ejecting the first liquid onto the medium; a conveying unit configured to relatively move the medium in a relative movement direction intersecting with the nozzle arrangement direction with respect to the print head; a control unit that controls ejection of liquid including the first liquid by the print head, The print head includes an overlapping portion where a portion of the first nozzle array overlaps a portion of the second nozzle array when viewed in the relative movement direction. In the overlapping portion, the first nozzle row is located upstream of the second nozzle row in the relative movement direction. In the nozzle arrangement direction, a boundary between the first printing area of ​​the first nozzle array and the second printing area of ​​the second nozzle array is located within the range of the overlapping portion. The plurality of first nozzles include a normal nozzle located in the first printing area and an anti-flow point forming nozzle located at an end portion of the second printing area on the side of the first printing area. The control unit causes the print head to form a plurality of non-adjacent flow prevention dots in the relative movement direction by ejecting the first liquid from the flow prevention dot forming nozzle toward the medium during printing.

2. The printing device according to claim 1, wherein The apparatus further comprises an operation receiving unit for receiving an operation of changing from the anti-flow point forming nozzle to the normal nozzle. When the change operation is received, the control unit changes the anti-flow dot forming nozzle to the normal nozzle, and controls the discharge of the liquid by the print head.

3. The printing device according to claim 1, wherein It also includes an operation receiving unit for receiving an operation for setting the size of the anti-flow point. Upon receiving the setting operation, the control unit causes the print head to form the plurality of flow prevention dots in the size.

4. A printing method comprising: moving a medium relative to a print head in a relative movement direction intersecting a predetermined nozzle arrangement direction, and ejecting a liquid including a first liquid from the print head toward the medium, wherein: The print head includes a first nozzle array formed by a plurality of first nozzles capable of ejecting the first liquid onto the medium and arranged in the nozzle array direction, and a second nozzle array formed by a plurality of second nozzles capable of ejecting the first liquid onto the medium and arranged in the nozzle array direction. The print head includes an overlapping portion where a portion of the first nozzle array overlaps a portion of the second nozzle array when viewed in the relative movement direction. In the overlapping portion, the first nozzle row is located upstream of the second nozzle row in the relative movement direction. In the nozzle arrangement direction, a boundary between the first printing area of ​​the first nozzle array and the second printing area of ​​the second nozzle array is located within the range of the overlapping portion. The plurality of first nozzles include a normal nozzle located in the first printing area and an anti-flow point forming nozzle located at an end portion of the second printing area on the side of the first printing area. In a case where stripes are generated between the first printing area and the second printing area due to the flow of the first liquid during printing without using the anti-flow point forming nozzle, a plurality of anti-flow points that are not adjacent to each other in the relative movement direction are formed by spraying the first liquid from the anti-flow point forming nozzle toward the medium.

5. A printing method comprising: moving a medium relative to a print head in a relative movement direction intersecting a predetermined nozzle arrangement direction, and ejecting a liquid including a first liquid from the print head toward the medium, wherein: The print head includes a first nozzle array formed by a plurality of first nozzles capable of ejecting the first liquid onto the medium and arranged in the nozzle array direction, and a second nozzle array formed by a plurality of second nozzles capable of ejecting the first liquid onto the medium and arranged in the nozzle array direction. The print head includes an overlapping portion where a portion of the first nozzle array overlaps a portion of the second nozzle array when viewed in the relative movement direction. In the overlapping portion, the first nozzle row is located upstream of the second nozzle row in the relative movement direction. When a pair of the first nozzle and the second nozzle having a corresponding position in the overlapping portion of the first nozzle array and a corresponding position in the overlapping portion of the second nozzle array is defined as a nozzle pair, the overlapping portion has n sets of the nozzle pairs arranged in the nozzle arrangement direction, where n is an integer greater than or equal to 2. The printing method comprises: a first test pattern printing step of printing a first test pattern for determining a usage range of the first nozzle and the second nozzle in the overlapping portion on the medium, wherein the first test pattern is printed with m sets of specific nozzle pairs, among the nozzle pairs, which use the first nozzle and the second nozzle for ejecting the first liquid, where m is an integer greater than or equal to 0 and less than n; a use range determination step of determining the use range based on the density of a specific area from the first printing position to the second printing position; The first printing position is a printing position of the first nozzle located closest to the second printing area of ​​the second nozzle column in the first printing area of ​​the first nozzle column in the first test pattern printed on the medium. The second printing position is a printing position of the second nozzle located closest to the first printing area in the second printing area of ​​the first test pattern printed on the medium. The plurality of first nozzles include a normal nozzle located in the first printing area and an anti-flow point forming nozzle located at an end portion of the second printing area on the side of the first printing area. The printing method also includes an anti-flow point forming process. In the anti-flow point forming process, when stripes are generated between the first printing area and the second printing area due to the flow of the first liquid during printing based on the usage range, a plurality of anti-flow points that are not adjacent to each other in the relative movement direction are formed by spraying the first liquid from the anti-flow point forming nozzle toward the medium.

6. The printing method according to claim 5, wherein: The process further includes a size setting acceptance step of accepting the setting of the size of the anti-flow point. In the flow prevention point forming step, the plurality of flow prevention points are formed in the size.

7. The printing method according to claim 5 or claim 6, wherein: Also includes: a second test pattern printing step of forming a second test pattern, the second test pattern being formed by ejecting the first liquid from the first nozzle array and the second nozzle array toward the medium so as to include the flow prevention dots, and including a plurality of independent patterns in which intervals between the flow prevention dots in the relative movement direction are varied; The interval determination step determines the interval between the flow prevention dots used in the flow prevention dot formation step based on the second test pattern.

8. The printing method according to claim 7, wherein: In the second test pattern printing step, the second test pattern is formed when at least one of the type of the medium and the type of the first liquid is changed.

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