Printing apparatus and printing method

Abstract

To enhance quality of printing an image.SOLUTION: A mix section, in a first head, that belongs to an overlap section disposed at a first position in a second direction and a mix section that belongs to an overlap section disposed at the first position in a second head are arranged in a first order so as to differ in terms of a position in the second direction. A mix section, in the first head, that belongs to the overlap section disposed at a second position in the second direction and a mix section that belongs to the overlap section disposed at the second position in the second head are arranged in a second order symmetrical to the first order so as to differ in terms of a position in the second direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a printing device and a printing method. [Background technology]

[0002] Patent Document 1 discloses a printer equipped with an inkjet head in which multiple chips that eject ink of the same color are arranged in a staggered pattern with partial overlap. In particular, Patent Document 1 discloses a configuration that suppresses banding by shifting the position of the mixed area of ​​each color (corresponding to the "mixed area" in this disclosure) in the same overlap area (corresponding to the "overlap area" in this disclosure) when viewed from the conveyance direction of the recording medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-150828 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration disclosed in Patent Document 1, the offset of the mixed area for each color is constant. In this configuration, the time difference between the timing at which a first color ink is ejected from both of two overlapping chips and the timing at which a second color ink is ejected from one of two overlapping chips varies depending on the location of the overlapping area. The position of the overlapping area here refers to the position as viewed from the conveyance direction of the recording medium. Therefore, in the above-mentioned document, the difference in the landing timing of the first color ink and the second color ink varies depending on the location of the overlapping area. This results in banding that has different characteristics from the banding that occurs in other overlapping areas, making the banding more noticeable. Therefore, there is a need for technology that can further improve the quality of image printing. [Means for solving the problem]

[0005] A printing device according to the present disclosure includes a head unit capable of ejecting a plurality of types of liquid, and a control unit that controls the ejection of the liquid from the head unit, and the head unit includes at least a first head including three or more chips each having a nozzle row configured from nozzles capable of ejecting a first liquid, and a second head including three or more chips each having a nozzle row configured from nozzles capable of ejecting a second liquid, the first head and the second head are arranged at intervals in a first direction, an arrangement of the three or more chips of the first head on the first head is the same as an arrangement of the three or more chips of the second head on the second head, the three or more chips are arranged in a staggered pattern in a second direction such that adjacent chips have an overlap section when viewed from the first direction, the second direction is a direction intersecting the first direction, and the overlap section of the first head and the overlap section of the second head are the first head and the second head overlap when viewed from a first direction, and the control unit controls the ejection of the liquid so that each of the overlapping sections has a mixing section in which the liquid is ejected from both of the two adjacent tips and a non-mixing section in which the liquid is ejected from only one of the tips, and the mixing section belonging to the overlapping section at a first position in the second direction for the first head and the mixing section belonging to the overlapping section at the first position for the second head are arranged in a first order so that their positions in the second direction are different, and the mixing section belonging to the overlapping section at a second position in the second direction for the first head and the mixing section belonging to the overlapping section at the second position for the second head are arranged in a second order symmetrical to the first order so that their positions in the second direction are different, and the first position and the second position are positions in the second direction of two overlapping sections that are adjacent in the second direction.

[0006] The pattern printing method of the present disclosure is a method for printing a pattern printed using the printing device, and includes: a first chip group is a set of chips arranged in a staggered pattern on the head that are arranged at a first position in the first direction; a second chip group is a set of chips arranged at a second position in the first direction; and a first ejection step is performed to eject colored ink from the nozzles of the first chip group that belong to a section other than the overlap section, the nozzles that belong to the mixed section, and the nozzles that belong to the non-mixed section in one of the chips; and a second ejection step is performed to eject the colored ink from the nozzles of the second chip group that belong to a section other than the overlap section, the nozzles that belong to the mixed section, and the nozzles that belong to the non-mixed section in one of the chips. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of a printing system according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating the configuration of a head unit. [Figure 3] FIG. 10 is a schematic diagram showing the arrangement of a mixed section according to a comparative example. [Figure 4] FIG. 10 is a schematic diagram showing the arrangement of a mixed section according to a comparative example. [Figure 5] FIG. 10 is a schematic diagram showing the arrangement of a mixed section according to an embodiment. [Figure 6] FIG. 10 is a schematic diagram showing the arrangement of a mixed section according to an embodiment. [Figure 7] FIG. 2 is a schematic block diagram of a control system of the printing system according to the embodiment. [Figure 8] FIG. 3 is an explanatory diagram of nozzles that are driven during printing. [Figure 9] FIG. 2 is a schematic diagram showing an example of a pattern printed on a recording medium. [Figure 10] FIG. 10 is a schematic diagram showing the arrangement of a mixed section according to a modified example of the embodiment. [Figure 11]FIG. 2 is a schematic diagram showing an example of a pattern printed on a recording medium. [Figure 12] FIG. 10 is a schematic diagram showing the arrangement of a mixed section according to a modified example of the embodiment. [Figure 13] FIG. 10 is a schematic diagram showing the arrangement of a mixed section according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In addition, in each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. In this disclosure, the expression "adjacent" is used not only when two elements are not interposed between them by an element of a different type from the two elements, but also when two elements are interposed by an element of a different type from the two elements. In this disclosure, the expression "connected" is used not only when multiple elements are not interposed between them by an element of a different type from the multiple elements, but also when multiple elements are interposed by an element of a different type from the multiple elements.

[0009] (Printing System) 1 is a schematic diagram of a printing system 1 according to an embodiment. The printing system 1 includes a terminal device 2 and a printing device 3 connected to the terminal device 2 so as to be able to communicate with each other.

[0010] The printing device 3 includes a head unit 11 capable of ejecting multiple types of liquid, a medium transport path 12 that extends through a printing position A printed by the head unit 11, and a transport unit 13 that is a transport mechanism that transports a recording medium Q in a transport direction B along the medium transport path 12. The transport unit 13 is mounted on a platen unit 14 that faces the head unit 11 vertically below the head unit 11 with a predetermined gap between them. The transport unit 13 includes an endless transport belt 17 that is stretched across multiple guide rollers 15 and a drive roller 16, and a transport motor 18 that rotates the drive roller 16 to rotate the transport belt 17. The transport unit 13 transports the recording medium Q at a constant speed by driving the transport motor 18.

[0011] (head unit) FIG. 2 is a schematic diagram showing the configuration of the head unit 11. As shown in FIG. 2, the head unit 11 includes four line-type inkjet heads, head 21, head 22, head 23, and head 24, arranged at a predetermined interval along the transport direction B of the recording medium Q. That is, head 21, head 22, head 23, and head 24 are aligned at intervals in the transport direction B. For example, these heads are aligned at equal intervals. Each of head 21, head 22, head 23, and head 24 is capable of ejecting liquid. Specifically, in this embodiment, head 21, which is located at the most upstream side in the transport direction B, ejects black ink, and head 22, located downstream thereof, ejects cyan ink. Furthermore, head 23, located downstream of head 22, ejects magenta ink, and head 24, located downstream thereof, ejects yellow ink.

[0012] Each of head 21, head 22, head 23, and head 24 has N chips arranged in a cross direction C that crosses the transport direction B. In this embodiment, specifically, N is 4. That is, each of head 21, head 22, head 23, and head 24 has four chips. Note that, although the value of N is 4 in this embodiment, it is not limited to 4 and may be any integer equal to or greater than 3. In addition, cross direction C is, more specifically, a direction that is perpendicular to the transport direction B.

[0013] In this embodiment, specifically, head 21 has chip 211, chip 212, chip 213, and chip 214. These four chips 211, 212, 213, and 214 are arranged in a staggered pattern along the cross direction C. In other words, the four chips 211, 212, 213, and 214 are arranged one behind the other in the transport direction B. Therefore, the chips of head 21 are divided into the following two chip groups. The first chip group of head 21 is a collection of chips arranged at a predetermined position in the transport direction B, specifically, the chip group consisting of chip 211 and chip 213. The second chip group of head 21 is a collection of chips arranged at a position other than the predetermined position in the transport direction B, specifically, the chip group consisting of chip 212 and chip 214.

[0014] Furthermore, when viewed from the transport direction B, adjacent chips of the four chips 211, 212, 213, and 214 partially overlap each other. That is, the chips provided in the head 21 are arranged so that adjacent chips have an overlapping section when viewed from the transport direction B. Here, the overlapping section refers to a section in which two chips belonging to the same head overlap when viewed from the transport direction B. Specifically, as shown in FIG. 2, chip 211 and chip 212 are arranged so as to have an overlapping section OL1. Furthermore, chip 212 and chip 213 are arranged so as to have an overlapping section OL2. Furthermore, chip 213 and chip 214 are arranged so as to have an overlapping section OL3.

[0015] Similarly, head 22 has chips 221, 222, 223, and 224 arranged in a staggered pattern. Therefore, head 22 has a first chip group consisting of chips 221 and 223 arranged at a predetermined position in transport direction B, and a second chip group consisting of chips 222 and 224 arranged at another position in transport direction B. Adjacent chips of head 22 also partially overlap when viewed from transport direction B. Specifically, as shown in FIG. 2, chips 221 and 222 are arranged so as to have an overlapping section OL1. Furthermore, chips 222 and 223 are arranged so as to have an overlapping section OL2. Furthermore, chips 223 and 224 are arranged so as to have an overlapping section OL3.

[0016] Similarly, head 23 has chips 231, 232, 233, and 234 arranged in a staggered pattern. Therefore, head 23 has a first chip group consisting of chips 231 and 233 arranged at a predetermined position in conveyance direction B, and a second chip group consisting of chips 232 and 234 arranged at another position in conveyance direction B. Adjacent chips in head 23 also partially overlap when viewed from conveyance direction B. Specifically, as shown in FIG. 2, chips 231 and 232 are arranged so as to have an overlapping section OL1. Chips 232 and 233 are arranged so as to have an overlapping section OL2. Chips 233 and 234 are arranged so as to have an overlapping section OL3.

[0017] Similarly, head 24 has chips 241, 242, 243, and 244 arranged in a staggered pattern. Therefore, head 24 has a first chip group consisting of chips 241 and 243 arranged at a predetermined position in transport direction B, and a second chip group consisting of chips 242 and 244 arranged at another position in transport direction B. Adjacent chips in head 24 also partially overlap when viewed from transport direction B. Specifically, as shown in FIG. 2, chips 241 and 242 are arranged so as to have an overlapping section OL1. Furthermore, chips 242 and 243 are arranged so as to have an overlapping section OL2. Furthermore, chips 243 and 244 are arranged so as to have an overlapping section OL3.

[0018] More specifically, in the overlap sections OL1 and OL3, the left end of the upstream chip and the right end of the downstream chip of each head overlap when viewed from the upstream side of the transport direction B. Note that the transport direction B refers to one direction in which the recording medium Q is transported (from right to left in FIG. 2 ), so it is clear that “viewed from the transport direction B” means “viewed from the upstream side of the transport direction B.” For this reason, hereinafter, “viewed from the upstream side of the transport direction B” will simply be referred to as “viewed from the transport direction B.” For example, in the case of head 21, in the overlap section OL1, the left end of the upstream chip 211 and the right end of the downstream chip 212 in the transport direction B overlap, and in the overlap section OL3, the left end of the upstream chip 213 and the right end of the downstream chip 214 in the transport direction B overlap. In contrast, in the overlap section OL2, the right end of the upstream chip and the left end of the downstream chip of each head overlap when viewed from the transport direction B. Note that Figure 2 shows only one example of the configuration of the head unit 11, and in each head, the positions of the first chip group and the second chip group in the transport direction B may be opposite to those shown in Figure 2.

[0019] As can be seen from the above description of heads 21 to 24 and from FIG. 2 , the arrangement of the four chips of head 21 on head 21, the arrangement of the four chips of head 22 on head 22, the arrangement of the four chips of head 23 on head 23, and the arrangement of the four chips of head 24 on head 24 are the same. That is, these arrangements are the same. As described above, in this embodiment, the number of chips in each head is not limited to four. Therefore, if the number of chips in each head is N, the following can be said for all integers n that satisfy 1≦n≦N−1. The nth overlap section of head 21, the nth overlap section of head 22, the nth overlap section of head 23, and the nth overlap section of head 24 are located at the same position in the cross direction C. In other words, the nth overlap section of each head, counted along the cross direction C, is located at the same position when viewed from the transport direction B. In other words, the nth overlap section, counted along the intersecting direction C of each head, overlaps when viewed from the transport direction B. In this disclosure, overlap sections are counted in order from the right when viewed from the transport direction B, that is, from the top of FIG. 2. In other words, the overlap section on the far right when viewed from the transport direction B is referred to as the first overlap section. In this way, the nth overlap section, counted from the right when viewed from the transport direction B, is located at the same position when viewed from the transport direction B in all heads. Therefore, overlap section OL1 can be said to be an overlap section common to all heads. The same is true for overlap sections OL2 and OL3.

[0020] Each chip of each head has a plurality of nozzles arranged in the intersecting direction C, as shown in FIG. 4 or FIG. 6 (described later). The plurality of nozzles in each chip are arranged in a staggered pattern along the intersecting direction C. In other words, the plurality of nozzles in each chip are arranged front to back in the transport direction B to form a nozzle row. Specifically, the nozzles 31 in each of the chips 211, 212, 213, and 214 of the head 21 are nozzles that eject black ink onto the recording medium Q. Furthermore, the nozzles 32 in each of the chips 221, 222, 223, and 224 of the head 22 are nozzles that eject cyan ink onto the recording medium Q. The nozzles 33 in each of the chips 231, 232, 233, and 234 of the head 23 are nozzles that eject magenta ink onto the recording medium Q. Furthermore, the nozzles 34 in each of the chips 241, 242, 243, and 244 of the head 24 are nozzles that eject yellow ink onto the recording medium Q. The arrangement of the nozzles 31 in the head 21, the arrangement of the nozzles 32 in the head 22, the arrangement of the nozzles 33 in the head 23, and the arrangement of the nozzles 34 in the head 24 are common. In other words, these arrangements are the same.

[0021] (Comparative Example) Next, we will explain a comparative example that was one of the reasons for conceiving this embodiment. Outside the overlapping section, each color ink is ejected from only one chip. In contrast, in the overlapping section, color ink can be ejected from both of the two overlapping chips. Here, a section within the overlapping section where color ink is ejected from both of the two chips is referred to as a mixed section. More specifically, a mixed section is a section defined within the overlapping section when viewed from the transport direction B, where color ink is ejected from both of two adjacent chips arranged to form the overlapping section. In contrast, a section within the overlapping section where color ink is ejected from only one of the two adjacent chips is referred to as a non-mixed section. Note that the mixed section can also be referred to as a section within the overlapping section where an image is formed on the recording medium Q by ejecting ink from two chips. Furthermore, the non-mixed section can also be referred to as a section within the overlapping section where an image is formed on the recording medium Q by ejecting ink from one chip.

[0022] FIG. 3 is a schematic diagram showing the arrangement of a mixed section according to a comparative example. In FIG. 3 and in FIGS. 5, 10, 12, and 13 described below, the areas in each chip where nozzles belonging to the mixed section are distributed are shown solid, and areas other than these areas where ink is ejected are hatched. Therefore, areas that are neither solid nor hatched indicate areas where unused nozzles are distributed. FIG. 4, like FIG. 3, is a schematic diagram showing the arrangement of a mixed section according to a comparative example, and in particular, is a schematic diagram showing the arrangement of the mixed section in overlap section OL1.

[0023] As described above, in the non-mixing section within the overlapping section, color ink is ejected from only one of the two overlapping chips. Specifically, the chip from which color ink is ejected in the non-mixing section is the chip from which the non-mixing section is set closer to the center of the chip than the mixed section, out of the two overlapping chips. This also applies to the embodiments. More specifically, the center of the chip refers to the center of the chip in the cross direction C. The chip from which ink is ejected in the non-mixing section will be described in more detail with reference to FIG. 4.

[0024] 4, the overlap section OL1 of the head 21 includes a non-mixing section Nb11 and a non-mixing section Nb12 in addition to the mixed section Mb1. Here, the non-mixing section Nb11 is located closer to the center of the tip 211 than the mixed section Mb1, and the non-mixing section Nb11 is located closer to the tip of the tip 212 than the mixed section Mb1, in the tip 211. The non-mixing section Nb12 is located closer to the tip of the tip 211 than the mixed section Mb1, and the non-mixing section Nb12 is located closer to the center of the tip 212 than the mixed section Mb1, in the tip 212. Therefore, the tip from which black ink is ejected in the non-mixing section Nb11 is the tip 211 of the two overlapping tips 211 and 212, which is the tip 211 in which the non-mixing section Nb11 is set closer to the center of the tip than the mixed section Mb1. Furthermore, the chip that ejects black ink in the non-mixing section Nb12 is chip 212, which is the chip of the two overlapping chips 211, 212 in which the non-mixing section Nb12 is set closer to the center of the chip than the mixed section Mb1. In other words, of the non-mixing section Nb11 and non-mixing section Nb12 included in the overlapping section OL1 of head 21, chip 211 ejects color ink in the non-mixing section Nb11 that is continuous with a section that is not the overlapping section OL1 of chip 211, and chip 212 ejects color ink in the non-mixing section Nb12 that is continuous with a section that is not the overlapping section OL1 of chip 212.

[0025] Similarly, the chip from which cyan ink is ejected in the non-mixing section Nc11 of the head 22 in the overlapping section OL1 is chip 221, of the two overlapping chips 221 and 222, which is the chip for which the non-mixing section Nc11 is set closer to the center of the chip than the mixing section Mc1. Furthermore, the chip from which cyan ink is ejected in the non-mixing section Nc12 of the head 22 in the overlapping section OL1 is chip 222, of the two overlapping chips 221 and 222, which is the chip for which the non-mixing section Nc12 is set closer to the center of the chip than the mixing section Mc1. Furthermore, the chip from which magenta ink is ejected in the non-mixing section Nm11 of the head 23 in the overlapping section OL1 is chip 231, of the two overlapping chips 231 and 232, which is the chip for which the non-mixing section Nm11 is set closer to the center of the chip than the mixing section Mc1. Furthermore, the tip from which magenta ink is ejected in the non-mixing section Nm12 of the head 23 in the overlapping section OL1 is tip 232, which is one of the two overlapping tips 231 and 232 and in which the non-mixing section Nm12 is set closer to the center of the tip than the mixing section Mm1. Furthermore, the tip from which yellow ink is ejected in the non-mixing section Ny11 of the head 24 in the overlapping section OL1 is tip 241, which is one of the two overlapping tips 241 and 242 and in which the non-mixing section Ny11 is set closer to the center of the tip than the mixing section My1. Furthermore, the tip from which yellow ink is ejected in the non-mixing section Ny12 of the head 24 in the overlapping section OL1 is tip 242, which is one of the overlapping tips 241 and 242 and in which the non-mixing section Ny12 is set closer to the center of the tip than the mixing section My1. The tips that eject ink in the non-mixing section of the overlapping section OL1 have been described above, but similar descriptions apply to other overlapping sections.

[0026] In the comparative example, the mixed sections of each head are arranged staggered in the cross direction C according to the same rule. Specifically, as shown in FIGS. 3 and 4, the mixed sections are arranged as follows. In the comparative example and the embodiment, each overlap section includes four partial sections that do not overlap each other, and the mixed section is arranged in one of the partial sections. In the present disclosure, these four partial sections are referred to as the first partial section, the second partial section, the third partial section, and the fourth partial section in order from the right side when viewed from the upstream side of the transport direction B, i.e., from the top of FIGS. 3 and 4. In the overlap section OL1, the mixed section Mb1 of the head 21 is arranged in the fourth partial section of the overlap section OL1. In the overlap section OL1, the mixed section Mc1 of the head 22 is arranged in the third partial section, the mixed section Mm1 of the head 23 is arranged in the second partial section, and the mixed section My1 of the head 24 is arranged in the first partial section. Similarly, in overlap section OL2, the mixed section Mb2 of head 21 is arranged in the fourth partial section, the mixed section Mc2 of head 22 is arranged in the third partial section, the mixed section Mm2 of head 23 is arranged in the second partial section, and the mixed section My2 of head 24 is arranged in the first partial section. Furthermore, in overlap section OL3, the mixed section Mb3 of head 21 is arranged in the fourth partial section, the mixed section Mc3 of head 22 is arranged in the third partial section, the mixed section Mm3 of head 23 is arranged in the second partial section, and the mixed section My3 of head 24 is arranged in the first partial section. In this way, the shifting of the positions of the mixed regions for each color is constant.

[0027] As in the comparative example, by shifting the mixed sections for each color in the overlap section, it is possible to suppress the occurrence of banding. However, even in the comparative example, it is difficult to completely eliminate banding, and the arrangement of the mixed sections in the comparative example still leaves the following issues regarding the occurrence of banding.

[0028] In FIG. 3, arrows 91 to 96 indicate the effective distance between the nozzles ejecting ink of the first head and the nozzles ejecting ink of the second head in a partial section where a mixed section of either the first head or the second head exists. The first head and the second head are adjacent heads, and in FIG. 3, heads 22 and 23 are focused on as the first head and the second head. Here, the discussion focuses on heads 22 and 23, but the following points also apply to other pairs of adjacent heads. In FIG. 3 and in FIGS. 5, 10, 12, and 13 described below, when illustrating each arrow indicating distance, for two chips that eject ink of the same color, the midpoint between those chips is shown as the effective nozzle position.

[0029] As shown in FIG. 3 , the arrows 93 and 94 in the overlap section OL2 are shorter than the arrows 91, 92, 95, and 96 in the overlap section OL1 or OL3. This means that in the overlap section OL2, the time interval between when the ink ejected from the head 22 (i.e., cyan ink) lands on the recording medium Q and when the ink ejected from the head 23 (i.e., magenta ink) lands on the recording medium Q is different from that in the other overlap sections. Specifically, in the example shown in FIG. 3 , the time interval between ink droplets landing in the overlap section OL2 is shorter than that in the other overlap sections. As described above, in the arrangement of the mixed sections shown in the comparative example, the shifting of the positions of the mixed regions for each color is constant, so the time interval between ink droplets landing in the overlap section OL2 is different from that in the other overlap sections. As a result, banding with different characteristics from the banding occurring in the overlap sections OL1 and OL3 occurs in the overlap section OL2, making the banding more noticeable. Therefore, in this embodiment, an arrangement of the mixed sections different from that in the comparative example is adopted.

[0030] Fig. 5 is a schematic diagram showing the arrangement of the mixed section according to the embodiment. Fig. 6 is a schematic diagram showing the arrangement of the mixed section according to the embodiment, similar to Fig. 5, and in particular the arrangement of the mixed section in the overlap section OL2.

[0031] In this embodiment, the mixed sections of each head are also arranged with a shift in the cross direction C. However, in this embodiment, the mixed sections are not shifted in the same way in all overlap sections, but two symmetrical shift patterns are alternately adopted for each overlap section. Specifically, as shown in Figures 5 and 6, each mixed section is arranged as follows:

[0032] In this embodiment, in the overlap section OL1, the mixed sections of each head are arranged in the same manner as in the comparative example. That is, in the overlap section OL1, the mixed section Mb1 of head 21 is arranged in the fourth partial section of the overlap section OL1. Then, in the overlap section OL1, the mixed section Mc1 of head 22 is arranged in the third partial section, the mixed section Mm1 of head 23 is arranged in the second partial section, and the mixed section My1 of head 24 is arranged in the first partial section. That is, in the overlap section OL1, the mixed sections of each of the heads 21, 22, 23, and 24 arranged in the conveying direction B are arranged so that the position of the mixed section becomes more to the right as viewed from the upstream side of the conveying direction B as the position of the head becomes more downstream in the conveying direction B. That is, the mixed sections of each head arranged in the conveying direction B are arranged in order from left to right as viewed from the upstream side of the conveying direction B. In this way, the overlap section OL1 employs the mixed section arrangement shown in FIG. 4.

[0033] 5 and 6, the mixed sections of the heads in the overlap section OL2 are arranged symmetrically with respect to the mixed sections in the overlap section OL1. Here, a symmetrical arrangement refers to an arrangement that is symmetrical with respect to an axis parallel to the conveying direction B. That is, in the overlap section OL2, the mixed section Mb2 of the head 21 is arranged in the first partial section of the overlap section OL2. In the overlap section OL2, the mixed section Mc2 of the head 22 is arranged in the second partial section, the mixed section Mm2 of the head 23 is arranged in the third partial section, and the mixed section My2 of the head 24 is arranged in the fourth partial section. That is, in the overlap section OL2, the mixed sections of the heads 21, 22, 23, and 24 aligned in the conveying direction B are arranged so that the position of the mixed section becomes more to the left as the head position becomes more downstream in the conveying direction B, as viewed from the upstream side of the conveying direction B. That is, the mixed sections of the heads aligned in the conveying direction B are arranged in order from right to left as viewed from the upstream side of the conveying direction B.

[0034] In the overlap section OL3, the mixed sections of each head are arranged in the same manner as in the overlap section OL1. That is, in the overlap section OL3, the mixed section Mb3 of head 21 is arranged in the fourth partial section of the overlap section OL3. In the overlap section OL3, the mixed section Mc3 of head 22 is arranged in the third partial section, the mixed section Mm3 of head 23 is arranged in the second partial section, and the mixed section My3 of head 24 is arranged in the first partial section. In this way, the overlap section OL3 also adopts the mixed section arrangement shown in FIG. 4, similar to the overlap section OL1.

[0035] In this embodiment, the mixing section is set so as not to include the end of the overlap section (more specifically, the end in the cross direction C), but it may be set so as to include the end of the overlap section. That is, in this embodiment, the mixing section is set so as not to use nozzles that belong to the tip of each tip in the cross direction C, but the mixing section may be set so as to use such nozzles as well.

[0036] 4 will be referred to as descending order for convenience, because the mixed sections of each head progress from the fourth partial section to the third partial section to the second partial section and the first partial section when viewed from the transport direction B. Similarly, the mixed section arrangement as shown in FIG. 6 will be referred to as ascending order for convenience.

[0037] Here, we consider the time interval between the landing of two colors of ink in this embodiment. In Figure 5, arrows 81 to 86 indicate the effective distance between the nozzles ejecting ink of the first head and the nozzles ejecting ink of the second head in a partial section where a mixing section of either the first head or the second head exists. Note that the first head and the second head are adjacent heads, and in Figure 5, heads 22 and 23 are also focused on as the first head and the second head. Here, we will again focus on heads 22 and 23, but the following points also apply to other pairs of adjacent heads.

[0038] In this embodiment, as described above, a symmetrical arrangement of mixed sections is adopted for each overlap section. That is, in this embodiment, descending and ascending order are alternately adopted for each overlap section. For this reason, as shown in FIG. 5, the lengths of arrows 81 to 86 are all the same. This means that in a partial section where a mixed section exists, the time interval between when ink ejected from head 22 lands on recording medium Q and when ink ejected from head 23 lands on recording medium Q is constant regardless of the overlap section. For this reason, it is possible to suppress the occurrence of peculiar banding as in the comparative example.

[0039] Generalizing the number of nozzles on each chip as N, the arrangement of mixed sections in this embodiment has the following characteristics. For all odd numbers i satisfying 1≦i≦N−1, the following can be said: The mixed section belonging to the ith overlap section of head 21, the mixed section belonging to the ith overlap section of head 22, the mixed section belonging to the ith overlap section of head 23, and the mixed section belonging to the ith overlap section of head 24 are arranged in a predetermined order in the cross direction C. In particular, these mixed sections are arranged in a predetermined order so that their positions in the cross direction C are different. In this embodiment, this predetermined order is conveniently referred to as descending order. Furthermore, the following can be said for all even numbers j satisfying 1≦j≦N−1: The mixed section belonging to the jth overlap section of head 21, the mixed section belonging to the jth overlap section of head 22, the mixed section belonging to the jth overlap section of head 23, and the mixed section belonging to the jth overlap section of head 24 are arranged in a symmetric order in the cross direction C. In particular, these mixed sections are arranged in a symmetrical order so that their positions in the cross direction C are different. Here, the symmetrical order is an order symmetrical to the above-mentioned predetermined order, and in this embodiment, it is an order referred to as ascending order for convenience. The arrangement of the mixed sections arranged in the predetermined order and the arrangement of the mixed sections arranged in the symmetrical order are symmetrical with respect to an axis parallel to the conveying direction B.

[0040] The arrangement of the mixed sections in the head unit 11 can also be explained as follows. The positions in the intersecting direction C of two overlapping sections that are adjacent to each other in the intersecting direction C will be referred to as the first position and the second position, and the four heads provided in the head unit 11 will be referred to as the first head, the second head, the third head, and the fourth head. In this case, the four mixed sections for the first to fourth heads that belong to the overlapping section at the first position can be said to be arranged in a first order (predetermined order) so that their positions in the intersecting direction C are different. Furthermore, the four mixed sections for the first to fourth heads that belong to the overlapping section at the second position can be said to be arranged in a second order (symmetric order) that is symmetrical to the first order so that their positions in the intersecting direction C are different.

[0041] Furthermore, when the number of chips included in each head of the head unit 11 is five or more, the arrangement of the mixed sections in the head unit 11 can be explained as follows. In this case, there are four overlapping sections connected in the intersecting direction C, and the positions of these four overlapping sections will be referred to as the first position, second position, third position, and fourth position. In this case, as described above, the four mixed sections for the first to fourth heads that belong to the overlapping section at the first position are arranged in a first order (predetermined order) so that their positions in the intersecting direction C are different. Furthermore, the four mixed sections for the first to fourth heads that belong to the overlapping section at the second position are arranged in a second order (symmetrical order) so that their positions in the intersecting direction C are different. Furthermore, it can be said that the four mixed sections for the first to fourth heads that belong to the overlapping section at the third position are arranged in a first order (predetermined order) so that their positions in the intersecting direction C are different. Furthermore, the four mixed sections for the first to fourth heads belonging to the overlap section at the fourth position can be said to be arranged in a second order (symmetric order) so that their positions in the cross direction C are different. In this way, the first order (predetermined order) and the second order (symmetric order) are repeated for each overlap section. The first position, second position, third position, and fourth position described above are defined in more detail as follows: The first position is the position of the first overlap section, counting along the cross direction C, among the four overlap sections connected in the cross direction C. The second position is the position of the second overlap section, counting along the cross direction C, among the four overlap sections connected in the cross direction C. The third position is the position of the third overlap section, counting along the cross direction C, among the four overlap sections connected in the cross direction C. The fourth position is the position of the fourth overlap section, counting along the cross direction C, among the four overlap sections connected in the cross direction C.

[0042] In this embodiment, the number of head units 11 is four, but the number of heads included in the head unit 11 may be two or more. Even when the number of heads included in the head unit 11 is not four but two, three, or five or more, the arrangement of the mixed sections can be explained in the same manner as above.

[0043] In addition, the above-mentioned descending or ascending order is such that the mixed sections of each head are arranged in a staircase pattern in the overlapping sections, as shown in FIG. 4 or FIG. 6. That is, the descending or ascending order shown in FIG. 4 or FIG. 6 is the following order. Note that, hereinafter, k is any integer satisfying 1≦k≦N−1. The mixed section belonging to the kth overlapping section of head 21 and the mixed section belonging to the kth overlapping section of head 22 are adjacent to each other in the crossing direction C. Furthermore, the mixed section belonging to the kth overlapping section of head 22 and the mixed section belonging to the kth overlapping section of head 23 are adjacent to each other in the crossing direction C. Furthermore, the mixed section belonging to the kth overlapping section of head 23 and the mixed section belonging to the kth overlapping section of head 24 are adjacent to each other in the crossing direction C.

[0044] The stepped arrangement of the mixed sections shown in FIG. 4 or 6 can also be explained as follows as the arrangement of mixed sections in a head unit having at least three heads. Here, the three heads included in the head unit 11 are referred to as the first head, the second head, and the third head. In this case, two mixed sections arranged in a first order (predetermined order) or a second order (symmetrical order) for two heads adjacent to each other in the transport direction B among the first head, the second head, and the third head are adjacent to each other in the cross direction C. For example, as shown in FIG. 4, the mixed section Mb1 and the mixed section Mc1 arranged in the first order (predetermined order) for the heads 21 and 22 adjacent to each other in the transport direction B are adjacent to each other in the cross direction C. Similarly, the mixed section Mc1 and the mixed section Mm1 arranged in the first order (predetermined order) for the heads 22 and 23 adjacent to each other in the transport direction B are adjacent to each other in the cross direction C. Similarly, the mixed sections Mm1 and My1 arranged in the first order (predetermined order) for the heads 23 and 24 adjacent to each other in the conveying direction B are adjacent to each other in the cross direction C. Here, the specific description has been given with reference to FIG. 4, but the same description can be given for mixed sections arranged in the second order (symmetric order) as shown in FIG. 6. In this way, the control unit 550, which will be described later, sets each mixed section so that two mixed sections arranged in the first order or the second order for two heads adjacent to each other in the conveying direction B among the first head, the second head, and the third head are adjacent to each other in the cross direction C. As a result, the position of each mixed section of the heads 21, 22, 23, and 24 arranged in the conveying direction B shifts in a certain direction as viewed from the upstream side of the conveying direction B as the position of the head moves downstream in the conveying direction B. In other words, the mixed sections are arranged in a stepped pattern.

[0045] By arranging the mixing region in a stepped pattern, the time interval between ink droplets landing on the recording medium Q in the mixing section of two adjacent heads in the transport direction B can be made constant regardless of the combination of the two adjacent heads. In other words, if the time interval between droplets landing in the mixing section of heads 22 and 23 indicated by arrows 81 to 86 in FIG. 5 is T, then the time interval between droplets landing in the mixing section of heads 21 and 22 and the time interval between droplets landing in the mixing section of heads 23 and 24 are both T. Therefore, for example, even if the heads responsible for cyan and magenta are changed from heads 22 and 23 to heads 23 and 24, the time interval between droplets landing on the recording medium Q will not change. This allows for flexible response to changes in the specifications of the printing device.

[0046] (Printing system control system) Fig. 7 is a schematic block diagram of the control system of the printing system 1. Fig. 8 is an explanatory diagram of the nozzles that are driven during printing.

[0047] The terminal device 2 includes a processor 400, a memory 410, and a communication interface 420, and has computer functions.

[0048] The memory 410 is configured, for example, by a combination of volatile memory and non-volatile memory. The memory 410 is used to store programs executed by the processor 400 and data used for various processes. The communication interface 420 is an interface used for communication with the printing device 3.

[0049] The processor 400 reads and executes programs from the memory 410. In this way, the processor 400 realizes the functions of an OS (operating system) 401, an application program 402, and a printer driver 403. The processor 400 may be, for example, a microprocessor, an MPU (microprocessor unit), or a CPU (central processing unit). The processor 400 may include multiple processors.

[0050] The OS 401 is software that controls the operation of the terminal device 2. The application program 402 is software that creates image data. The printer driver 403 receives image data from the application program 402 via the OS 401 and supplies the image data to the printing device 3.

[0051] The printing device 3 has a processor 500, a memory 510, and a communication interface 520, and has the functionality of a computer.

[0052] The memory 510 is configured, for example, by a combination of volatile memory and non-volatile memory. The memory 510 is used to store programs executed by the processor 500 and data used for various processes. The communication interface 520 is an interface used for communication with the terminal device 2.

[0053] The processor 500 reads and executes a program from the memory 510. In this way, the processor 500 realizes the functions of the control unit 550. The processor 500 may be, for example, a microprocessor, an MPU, or a CPU. The processor 500 may include multiple processors.

[0054] The communication interface 520 receives image data supplied from the terminal device 2 (printer driver 403) and inputs it to the processor 500. The head unit 11 and the transport motor 18 are connected to the processor 500 via a device driver (not shown).

[0055] The control unit 550 controls printing. That is, the control unit 550 controls the ejection of liquid (ink) from the head unit 11 and the transportation of the recording medium Q. In particular, as described above, the control unit 550 controls the ejection of ink so that each overlapping section has a mixed section and a non-mixed section that are aligned as described above. In this embodiment, the control unit 550 has an image processing unit 551 and a print control unit 552 to control printing. The image processing unit 551 first performs rendering processing on the image data input to the processor 500 and converts each pixel of the image data into RGB data. Here, R means red, G means green, and B means blue. Next, the image processing unit 551 converts the RGB data of each pixel into CMYK data by referring to a lookup table. Here, C means cyan, M means magenta, Y means yellow, and K means black. Next, the image processing unit 551 performs halftone processing based on the CMYK data to generate print data in a format that can be interpreted by the printing device 3. Note that when generating print data, the image processing unit 551 may adjust the amount of ink ejected to suppress banding. The print data is a group of commands that cause each nozzle of the head unit 11 to eject ink, and specifies which nozzles to drive (i.e., which nozzles eject ink). The print data is also referred to as dot data. In this way, the image processing unit 551 generates print data that drives the nozzles of each head of the head unit 11 based on the image data.

[0056] In particular, when generating print data, image processing unit 551 sets mixed sections and non-mixed sections for each overlap section as described above, and then generates the print data. Therefore, image processing unit 551 generates print data that drives both nozzles of two adjacent chips for mixed sections within the overlap section, and generates print data that drives one nozzle of two adjacent chips for non-mixed sections within the overlap section and sections other than the overlap section.

[0057] In other words, the image processing unit 551 generates print data that drives both nozzles of two adjacent chips for pixels formed in a portion corresponding to a mixed section on the recording medium Q passing through the printing position A. The image processing unit 551 also generates print data that drives one nozzle of two adjacent chips for pixels formed in a portion corresponding to a non-mixed section or a section other than the overlap section on the recording medium Q passing through the printing position A.

[0058] In order to suppress banding due to individual differences between nozzles, the print data for driving the mixed section may be data for controlling the ratio of the ink ejection amounts from two adjacent chips as follows. FIG. 8 is a schematic diagram for explaining the ratio of the ink ejection amounts from two adjacent chips. FIG. 8 shows chips 211 and 212 as representative of the two adjacent chips. More specifically, the upper part of FIG. 8 schematically shows the periphery of the overlap section OL1 between chips 211 and 212 of head 21, and the lower part of FIG. 8 is a graph showing the ratio of the ejection amounts between chips 211 and 212. As shown in FIG. 8, the image processing unit 551 may generate the following print data. In this example, the chip on one side of the two adjacent chips in the intersecting direction C (chip 211 in FIG. 8) will be referred to as the first chip, and the chip on the other side of the intersecting direction C (chip 212 in FIG. 8) will be referred to as the second chip. The image processing unit 551 may generate print data in which, in the mixed section, the ejection volume of each nozzle of the first chip is decreased toward the nozzles located on the other side of the intersecting direction C, and in which, in the mixed section, the ejection volume of each nozzle of the second chip is decreased toward the nozzles located on one side of the intersecting direction C. However, this type of ejection volume control is merely an example, and the ejection volume does not necessarily have to be controlled in this manner.

[0059] In this embodiment, the control unit 550 particularly arranges the mixed sections as follows. That is, as shown in FIGS. 4 and 6, two mixed sections arranged in the first order (predetermined order) or the second order (symmetric order) and adjacent to each other in the cross direction C are adjacent to each other with no gap between them. That is, as viewed from the conveying direction B, no non-mixed section is inserted between such two mixed sections. For example, as shown in FIG. 4, two mixed sections, Mb1 and Mc1, arranged in the first order and adjacent to each other in the cross direction C are adjacent to each other with no gap between them in the cross direction C. Similarly, two mixed sections, Mc1 and Mm1, arranged in the first order and adjacent to each other in the cross direction C are adjacent to each other with no gap between them in the cross direction C. Similarly, two mixed sections, Mm1 and My1, arranged in the first order and adjacent to each other in the cross direction C are adjacent to each other with no gap between them in the cross direction C. While the specific description has been given with reference to FIG. 4, the same description can be given for mixed sections arranged in the second order (symmetric order) as shown in FIG. 6. The above-described feature can also be explained as follows. For all integers n satisfying 1≦n≦N−1, adjacent mixed sections in the intersecting direction C that belong to the nth overlap section are arranged adjacent to each other. By arranging the mixed sections without gaps in this way, the mixed sections can be set longer within the overlap section than when the mixed sections are arranged with gaps. Therefore, when the ink ejection amount in the mixed section is reduced according to the position in the intersecting direction C as shown in FIG. 8, the change in the ink ejection amount according to the position can be made gentler. This makes it possible to more effectively suppress banding caused by differences in the performance of the nozzles of two adjacent chips. In particular, the more heads the head unit 11 has, the more mixed sections need to be arranged within the overlap section. Therefore, when the head unit 11 has a large number of heads, as in this embodiment, it is preferable to arrange the mixed sections without gaps.

[0060] When the print data is generated, the print control unit 552 drives the transport motor 18 to transport the recording medium Q at a predetermined speed along the medium transport path 12. The print control unit 552 also drives the head unit 11 based on the print data to print on the recording medium Q at the printing position A. That is, the print control unit 552 controls the ejection of ink from each head based on the print data to print on the recording medium Q.

[0061] The printing device 3 according to the embodiment has been described above. Unlike the comparative example described above, the printing device 3 employs a special method for shifting the position of the mixed region for each color. This makes it possible to prevent banding from becoming conspicuous due to banding occurring in some overlapping sections with characteristics different from banding occurring in other overlapping sections. Furthermore, because the banding occurring in each overlapping section is at the same level, it is easier to suppress banding by adjusting the amount of ink ejection compared to when banding of various levels occurs.

[0062] Incidentally, the printing device 3 can print any image on the recording medium Q under the control of the control unit 550, but it may also print a check pattern to check whether there are any defects in the nozzles of the head unit 11 (for example, clogged nozzles).

[0063] FIG. 9 is a schematic diagram showing an example of a pattern printed on a recording medium Q to check for nozzle defects in the head unit 11 when mixed sections and non-mixed sections are arranged in each overlap section as shown in FIG. 5. More specifically, FIG. 9 is a schematic plan view of the recording medium Q on which a pattern is printed. In FIG. 9, the test pattern printed on the recording medium Q includes patches P211 to P214 printed by head 21, patches P221 to P224 printed by head 22, patches P231 to P234 printed by head 23, and patches P241 to P244 printed by head 24. More specifically, patch P211 is printed by chip 211, patch P212 is printed by chip 212, patch P213 is printed by chip 213, and patch P214 is printed by chip 214. This correspondence between the patches and the chips is also true for the other patches.

[0064] Each patch is printed by ejecting ink from nozzles belonging to sections other than the overlap section, nozzles belonging to the mixed section, and nozzles belonging to the non-mixed section of the chip that is responsible for ejecting ink in the non-mixed section, under the control of the control unit 550. For example, patch P211 is printed by ejecting ink from all of the nozzles of chip 211 that are in sections other than the overlap section OL1, the nozzles of the mixed section Mb1, and the nozzles of the non-mixed section Nb11 (see FIG. 4). In other words, among the nozzles of chip 211, nozzles that do not fall into these categories, i.e., nozzle Nb12 in the overlapping section OL1, are not used to print the test pattern.

[0065] In order to print the test pattern shown in FIG. 9, the control unit 550 performs the following control while transporting the recording medium Q. The control unit 550 first controls the nozzles of the chips 241 and 243 of the head 24 to eject yellow ink from the nozzles used to print the patches P241 and P243. Next, the control unit 550 controls the nozzles of the chips 242 and 244 of the head 24 to eject yellow ink from the nozzles used to print the patches P242 and P244. Next, the control unit 550 controls the nozzles of chip 231 and chip 233 of the head 23 to eject magenta ink from the nozzles used to print patches P231 and P233. Next, the control unit 550 controls the nozzles of chip 232 and chip 234 of the head 23 to eject magenta ink from the nozzles used to print patches P232 and P234. Next, the control unit 550 controls the nozzles of chip 221 and chip 223 of the head 22 to eject cyan ink from the nozzles used to print patches P221 and P223. Next, the control unit 550 controls the nozzles of chip 222 and chip 224 of the head 22 to eject cyan ink from the nozzles used to print patches P222 and P224. Next, the control unit 550 controls the nozzles of chip 211 and chip 213 of the head 21 to eject black ink from the nozzles used to print patches P211 and P213. And finally, the control unit 550 controls the nozzles of chip 212 and chip 214 of the head 21 to eject black ink from the nozzles used to print patches P212 and P214. Note that, here, an example has been shown in which printing of the test pattern proceeds in the order of printing patches by head 24 (yellow ink), printing patches by head 23 (magenta ink), printing patches by head 22 (cyan ink), and printing patches by head 21 (black ink). However, when printing the test pattern on the recording medium Q, the order of the colors of the patches printed can be any order. For example, printing of the test pattern may proceed in the reverse order to the above-described order, i.e., printing patches by head 21 (black ink), printing patches by head 22 (cyan ink), printing patches by head 23 (magenta ink), and printing patches by head 24 (yellow ink).

[0066] By printing such a test pattern, it is possible to obtain a test pattern suitable for checking for defects in nozzles that are actually used in the printing device 3 of this embodiment. Note that, although the test pattern shown in Fig. 9 has patches printed for all heads, patches may be printed only for some heads, or patches may be printed only for some chips of some heads.

[0067] (Variation) In the mixed section arrangement shown in FIG. 5, the mixed sections are arranged in descending order in the overlap section OL1 and the overlap section OL3, and in ascending order in the overlap section OL2. However, as shown in FIG. 10, the mixed sections may be arranged in ascending order in the overlap section OL1 and the overlap section OL3, and in descending order in the overlap section OL2. That is, it is sufficient that the ascending and descending order is repeated for each overlap section. In this case, the lengths of the arrows 71 to 76 (i.e., the time intervals between ink landings) remain the same. When the mixed section arrangement shown in FIG. 10 is set, a test pattern such as that shown in FIG. 11 is printed by the printing device 3 on the recording medium Q to check for nozzle defects in the head unit 11.

[0068] Furthermore, in the mixed section arrangements shown in FIG. 5 or FIG. 10, the mixed sections of each head are arranged in a stepped manner in the same overlap section, but they do not necessarily have to be arranged in a stepped manner. For example, mixed sections may be arranged as shown in FIG. 12. The example of the mixed section arrangement shown in FIG. 12 is a modification of the mixed section arrangement shown in FIG. 13, which is a comparative example. In the example shown in FIG. 13, the mixed sections of each head are not arranged in a stepped manner, and are arranged the same in all overlap sections. In contrast, in the example shown in FIG. 12, the mixed sections of each head in overlap section OL2 are arranged symmetrically with the mixed sections of each head in overlap sections OL1 and OL3.

[0069] In FIG. 12, arrows 61 to 69 indicate the effective distance in a mixing section between the nozzles ejecting ink of one of two adjacent heads in the transport direction B and the nozzles ejecting ink of the other head. Similarly, in FIG. 13, arrows 51 to 59 indicate the effective distance in a mixing section between the nozzles ejecting ink of one of two adjacent heads in the transport direction B and the nozzles ejecting ink of the other head. As shown in FIG. 13, for each pair of heads, the length of the arrow in overlap section OL2 (i.e., the time interval between ink landings) is different from the lengths of the arrows in overlap sections OL1 and OL3 (i.e., the time interval between ink landings). In contrast, in the example shown in FIG. 12, the length of the arrow between head 21 and head 22 (i.e., the time interval between ink landings) is the same regardless of the overlap section. Similarly, in FIG. 12, the length of the arrow between head 22 and head 23 (i.e., the time interval between ink landings) is the same regardless of the overlap section, and the length of the arrow between head 23 and head 24 (i.e., the time interval between ink landings) is also the same regardless of the overlap section. Therefore, as with the above-described embodiment, it is possible to suppress the occurrence of banding. However, while in the above-described embodiment in which the mixing section is arranged in a stepped manner, the time interval between ink landings is a constant time T for any pair of heads, in the arrangement example shown in FIG. 12, the time interval between ink landings for the pair of heads 21 and 22 (arrows 67, 68, 69) differs from that for other pairs of heads, as shown in FIG.

[0070] Furthermore, in the above-described embodiment, the printing device 3 is equipped with the image processing unit 551, but the image processing unit 551 may also be provided on the terminal device 2 side. In this case, the printing device 3 and the terminal device 2 may be collectively referred to as the printing device. In other words, the printing system 1 may be referred to as the printing device.

[0071] In the present disclosure, a program includes a set of instructions (or software code) that, when loaded into a computer, causes the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray (registered trademark) disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0072] Furthermore, the present invention is not limited to the above-described embodiment and its modifications, and can be modified as appropriate within the scope of the invention.

[0073] Some or all of the above-described embodiments and modified examples can be described as, but are not limited to, the following supplementary notes. (Appendix 1) a head unit capable of ejecting a plurality of types of liquid; a control unit that controls the ejection of the liquid from the head unit; and The head unit includes: a first head including three or more chips each having a nozzle row made up of nozzles capable of ejecting a first liquid; a second head including three or more chips each having a nozzle row made up of nozzles capable of ejecting a second liquid; and the first head and the second head are spaced apart in a first direction, an arrangement of the three or more chips of the first head in the first head and an arrangement of the three or more chips of the second head in the second head are common; the three or more chips are arranged in a staggered pattern in a second direction such that adjacent chips have overlapping sections when viewed from the first direction, and the second direction is a direction intersecting the first direction; the overlap section of the first head and the overlap section of the second head overlap when viewed from the first direction, the control unit controls the ejection of the liquid so that each of the overlapping sections has a mixing section in which the liquid is ejected from both of the two adjacent tips and a non-mixing section in which the liquid is ejected from only one of the tips; the mixed section belonging to the overlap section at a first position in the second direction for the first head and the mixed section belonging to the overlap section at the first position for the second head are arranged in a first order such that their positions in the second direction are different; the mixed section belonging to the overlap section at a second position in the second direction for the first head and the mixed section belonging to the overlap section at the second position for the second head are arranged in a second order symmetrical to the first order such that their positions in the second direction are different; The first position and the second position are positions in the second direction of two overlapping sections that are adjacent in the second direction. Printing device. (Appendix 2) the first head and the second head each include five or more of the tips; the mixed section belonging to the overlap section at a third position in the second direction for the first head and the mixed section belonging to the overlap section at the third position for the second head are arranged in the first order such that their positions in the second direction are different; the mixed section belonging to the overlap section at a fourth position in the second direction for the first head and the mixed section belonging to the overlap section at the fourth position for the second head are arranged in the second order such that their positions in the second direction are different; the first position, the second position, the third position, and the fourth position are positions in the second direction of four overlapping sections that are successive in the second direction, the first position is the position of the first overlap section among the four overlap sections, counted along the second direction; the second position is a position of a second overlapping section among the four overlapping sections, counting along the second direction; the third position is a position of a third overlap section among the four overlap sections, counted along the second direction; The fourth position is the position of the fourth overlap section among the four overlap sections, counted along the second direction. 10. The printing device of claim 1. (Appendix 3) Two of the mixed sections arranged in the first order or the second order and adjacent to each other in the second direction are adjacent to each other without any gaps, 3. The printing device of claim 1 or 2. (Appendix 4) the head unit further includes a third head including three or more chips each having a nozzle row made up of nozzles capable of ejecting a third liquid; the first head, the second head, and the third head are spaced apart in the first direction, an arrangement of the three or more chips of the first head, an arrangement of the three or more chips of the second head, and an arrangement of the three or more chips of the third head are common to each other; the overlap section of the first head, the overlap section of the second head, and the overlap section of the third head overlap each other when viewed from the first direction, the mixed section belonging to the overlap section at the first position in the second direction for the first head, the mixed section belonging to the overlap section at the first position for the second head, and the mixed section belonging to the overlap section at the first position for the third head are arranged in the first order such that their positions in the second direction are different; the mixed section belonging to the overlap section at the second position in the second direction for the first head, the mixed section belonging to the overlap section at the second position for the second head, and the mixed section belonging to the overlap section at the second position for the third head are arranged in the second order such that their positions in the second direction are different; The two mixing sections arranged in the first order or the second order for two heads adjacent to each other in the first direction among the first head, the second head, and the third head are adjacent to each other in the second direction. 4. A printing device according to any one of claims 1 to 3. (Appendix 5) A method for printing a pattern using the printing device according to any one of Supplementary Notes 1 to 4, comprising: Among the chips arranged in a staggered pattern on the head, a set of the chips arranged at a first position in the first direction is defined as a first chip group, and a set of the chips arranged at a second position in the first direction is defined as a second chip group, a first ejection step of ejecting color ink from the nozzles of the first chip group that belong to a section other than the overlap section, the nozzles that belong to the mixed section, and the nozzles that belong to the non-mixed section of one of the chips; a second ejection step of ejecting the color ink from the nozzles of the second chip group that belong to a section other than the overlap section, the nozzles that belong to the mixed section, and the nozzles that belong to the non-mixed section of the one chip; A method for printing a pattern, comprising: [Explanation of symbols]

[0074] 1...printing system, 2...terminal device, 3...printing device, 11...head unit, 12...media transport path, 13...transport section, 14...platen unit, 15...guide roller, 16...drive roller, 17...transport belt, 18...transport motor, 21-24...head, 31-34...nozzle, 211-214...chip, 221-224...chip, 231-234...chip, 241-244...chip, 400...processor, 402...application program, 403...printer driver, 410...memory, 420...communication interface, 500...processor, 510...memory, 5 20...communication interface, 550...control unit, 551...image processing unit, 552...printing control unit, A...printing position, B...conveyance direction, C...cross direction, Mb1 to Mb3...mixed section, Mc1 to Mc3...mixed section, Mm1 to Mm3...mixed section, My1 to My3...mixed section, Nb11 to Nb12...non-mixed section, Nc11 to Nc12...non-mixed section, Nm11 to Nm12...non-mixed section, Ny11 to Ny12...non-mixed section, OL1 to OL3...overlapping section, P211 to P214...patches, P221 to P224...patches, P231 to P234...patches, P241 to P244...patches, Q...recording medium

Claims

1. a head unit capable of ejecting a plurality of types of liquid; a control unit that controls the ejection of the liquid from the head unit; and The head unit includes: a first head including three or more chips each having a nozzle row made up of nozzles capable of ejecting a first liquid; a second head including three or more chips each having a nozzle row made up of nozzles capable of ejecting a second liquid; and the first head and the second head are spaced apart in a first direction, an arrangement of the three or more chips of the first head in the first head and an arrangement of the three or more chips of the second head in the second head are common; the three or more chips are arranged in a staggered pattern in a second direction such that adjacent chips have overlapping sections when viewed from the first direction, and the second direction is a direction intersecting the first direction; the overlap section of the first head and the overlap section of the second head overlap when viewed from the first direction, the control unit controls the ejection of the liquid so that each of the overlapping sections has a mixing section in which the liquid is ejected from both of the two adjacent tips and a non-mixing section in which the liquid is ejected from only one of the tips; the mixed section belonging to the overlap section at a first position in the second direction for the first head and the mixed section belonging to the overlap section at the first position for the second head are arranged in a first order such that their positions in the second direction are different; the mixed section belonging to the overlap section at a second position in the second direction for the first head and the mixed section belonging to the overlap section at the second position for the second head are arranged in a second order symmetrical to the first order such that their positions in the second direction are different; The first position and the second position are positions in the second direction of two overlapping sections that are adjacent in the second direction. Printing device.

2. the first head and the second head each include five or more of the tips; the mixed section belonging to the overlap section at a third position in the second direction for the first head and the mixed section belonging to the overlap section at the third position for the second head are arranged in the first order such that their positions in the second direction are different; the mixed section belonging to the overlap section at a fourth position in the second direction for the first head and the mixed section belonging to the overlap section at the fourth position for the second head are arranged in the second order such that their positions in the second direction are different; the first position, the second position, the third position, and the fourth position are positions in the second direction of four overlapping sections that are successive in the second direction, the first position is a position of a first overlap section among the four overlap sections, counted along the second direction; the second position is a position of a second overlapping section among the four overlapping sections, counting along the second direction; the third position is a position of a third overlap section among the four overlap sections, counted along the second direction; The fourth position is the position of the fourth overlap section among the four overlap sections, counted along the second direction. The printing device of claim 1 .

3. Two mixing sections arranged in the first order or the second order and adjacent to each other in the second direction are adjacent to each other without any gaps, 3. The printing device according to claim 1 or 2.

4. the head unit further includes a third head including three or more chips each having a nozzle row configured from nozzles capable of ejecting a third liquid; the first head, the second head, and the third head are spaced apart in the first direction, an arrangement of the three or more chips of the first head, an arrangement of the three or more chips of the second head, and an arrangement of the three or more chips of the third head are common to each other; the overlap section of the first head, the overlap section of the second head, and the overlap section of the third head overlap each other when viewed from the first direction, the mixed section belonging to the overlap section at the first position in the second direction for the first head, the mixed section belonging to the overlap section at the first position for the second head, and the mixed section belonging to the overlap section at the first position for the third head are arranged in the first order such that their positions in the second direction are different; the mixed section belonging to the overlap section at the second position in the second direction for the first head, the mixed section belonging to the overlap section at the second position for the second head, and the mixed section belonging to the overlap section at the second position for the third head are arranged in the second order such that their positions in the second direction are different; Two of the mixing sections arranged in the first order or the second order for two heads adjacent to each other in the first direction among the first head, the second head, and the third head are adjacent to each other in the second direction. The printing device of claim 1 .

5. A method for printing a pattern using the printing device according to claim 1, comprising: Among the chips arranged in a staggered pattern on the head, a set of the chips arranged at a first position in the first direction is defined as a first chip group, and a set of the chips arranged at a second position in the first direction is defined as a second chip group, a first ejection step of ejecting color ink from the nozzles of the first chip group that belong to a section other than the overlap section, the nozzles that belong to the mixed section, and the nozzles that belong to the non-mixed section of one of the chips; a second ejection step of ejecting the color ink from the nozzles of the second chip group that belong to a section other than the overlap section, the nozzles that belong to the mixed section, and the nozzles that belong to the non-mixed section of the one chip; A method for printing a pattern, comprising:

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