Printing method and printing apparatus

Abstract

Crosstalk that occurs during the flushing process may affect the quality of the image formed on the medium. [Solution] In the printing method according to the present disclosure, a first discharge, which is the discharge of liquid for forming an image on a medium P, and a second discharge, which is the discharge of liquid for flushing in a predetermined area outside the end of the medium P in the main scanning direction, are performed in one pass, which is a single movement of the carriage 22 in a predetermined direction, and the second discharge for the nozzle row to be flushed is performed at a timing when the affected nozzle row is located outside the medium P and at least a part of the carriage 22 is in a position overlapping with the medium P when viewed from the direction of the liquid discharge.

Description

Technical Field

[0001] The present disclosure relates to a printing method and a printing apparatus.

Background Art

[0002] As maintenance for preventing or eliminating poor discharge of liquid from nozzles, flushing that discharges liquid from nozzles is known. In this regard, Patent Document 1 discloses a technique for efficiently performing flushing during image formation by adding flushing data for discharging ink in an ink receiving area provided at a position corresponding to the end of a sheet to print data.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, crosstalk is known, which is a phenomenon in which deformation of a flow path such as a liquid chamber leading to a certain nozzle that occurs when discharging liquid from the nozzle affects the discharge of liquid from other nozzles in the vicinity. According to the technique of Patent Document 1, it is possible to efficiently perform flushing during image formation, but there is a risk of affecting the quality of an image formed on a medium due to the influence of crosstalk that occurs during the execution of flushing.

Means for Solving the Problems

[0005] The printing method according to this disclosure is a printing method using a printing apparatus comprising: a print head having a plurality of nozzle rows; a carriage on which the print head is mounted; and a control unit that controls the discharge of liquid from the nozzle rows and the movement of the carriage in the main scanning direction, wherein a first discharge, which is the discharge of the liquid for forming an image on a medium, and a second discharge, which is the discharge of the liquid for flushing in a predetermined area outside the end of the medium in the main scanning direction, are performed during one pass operation of the carriage, the second discharge is performed on the nozzle row to be flushed, which is the nozzle row on which the second discharge is performed, at a timing when the affected nozzle row is located outside the medium and at least a part of the carriage is in a position overlapping with the medium when viewed from the direction of liquid discharge, the one pass operation is an operation in which the carriage moves once in any one direction of the main scanning direction, and the affected nozzle row is the nozzle row that is affected by the discharge of the liquid due to the execution of the second discharge by the nozzle row to be flushed.

[0006] The printing apparatus according to this disclosure comprises a print head having a plurality of nozzle rows, a carriage on which the print head is mounted, and a control unit that controls the discharge of liquid from the nozzle rows and the movement of the carriage in the main scanning direction, wherein the control unit performs a first discharge, which is the discharge of the liquid for forming an image on a medium, and a second discharge, which is the discharge of the liquid for flushing in a predetermined area outside the edge of the medium in the main scanning direction, during one pass operation of the carriage, wherein the second discharge is performed on the nozzle row to be flushed, which is the nozzle row on which the second discharge is performed, at a timing when the affected nozzle row is located outside the medium and at least a part of the carriage is in a position overlapping with the medium when viewed from the direction of liquid discharge, the one pass operation is an operation in which the carriage moves once in one direction of the main scanning direction, and the affected nozzle row is the nozzle row that is affected by the discharge of the liquid due to the execution of the second discharge by the nozzle row to be flushed. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing the general configuration of the printing apparatus according to the embodiment. [Figure 2] This is a schematic diagram of a print head according to an embodiment. [Figure 3] This is a schematic diagram showing an example of the area where a nozzle row and a flow path for the nozzle row exist. [Figure 4] This is a schematic diagram showing an example of the configuration of a platen according to the embodiment. [Figure 5] This is a schematic diagram showing liquid discharge data for performing image formation and flushing in a single pass. [Figure 6] This is a schematic diagram illustrating the flushing process in the comparative example. [Figure 7] This is a schematic diagram illustrating the flushing according to the embodiment. [Figure 8] This is a schematic diagram illustrating the flushing according to the embodiment. [Figure 9] This flowchart shows an example of the operation flow of a printing apparatus according to an embodiment. [Figure 10] This is a schematic diagram illustrating the flushing process performed when two nozzle rows on either side of the nozzle row to be flushed are also affected nozzle rows. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings. For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In addition, the same elements are denoted by the same reference numerals in each drawing, and redundant explanations have been omitted where necessary.

[0009] Figure 1 is a schematic diagram showing the configuration of a printing device 20 according to an embodiment. The printing device 20 is an inkjet printer that performs printing using ink by an inkjet method.

[0010] The printing apparatus 20 of this embodiment, as an example, comprises a paper feeding mechanism 31, a printer mechanism 21, and a control unit 70, as shown in Figure 1. The paper feeding mechanism 31 transports the medium P in the Y direction in the figure (i.e., the direction referred to as the transport direction or sub-scanning direction) by driving the paper feeding roller 35 with a drive motor 33. The medium P is, for example, paper, but is not limited to paper and may be a medium of any material such as a resin film. The printer mechanism 21 performs printing by ejecting liquid (ink droplets) from the print head 24 onto the medium P transported on the platen 51 by the paper feeding mechanism 31. The control unit 70 controls the entire printing apparatus 20. In particular, in this embodiment, the control unit 70 controls the ejection of liquid from the nozzle row of the print head 24 and the movement of the carriage 22, which will be described later, in the X direction in the figure (i.e., the so-called main scanning direction). In the figure, the Z direction represents the direction of liquid ejection.

[0011] The printer mechanism 21 includes, as an example, a carriage motor 34a, a driven roller 34b, a carriage belt 32, a carriage 22, an ink cartridge 26, and a print head 24. The carriage motor 34a is located on one end of the mechanical frame 21a (right side in the figure), and the driven roller 34b is located on the other end of the mechanical frame 21a (left side in the figure). The carriage belt 32 is stretched between the carriage motor 34a and the driven roller 34b. The carriage 22 moves back and forth along the guide 28 in the main scanning direction by the carriage belt 32 in conjunction with the drive of the carriage motor 34a. The ink cartridge 26 is mounted on the carriage 22 and contains individual CMYK inks of cyan (C), magenta (M), yellow (Y), and black (K), each containing a dye or pigment as a coloring agent in water as a solvent. The print head 24 receives ink from the ink cartridge 26 and ejects ink droplets. The print head 24 is mounted on the carriage 22 and moves in the main scanning direction as the carriage 22 moves.

[0012] Figure 2 is a schematic diagram of the print head 24. More specifically, Figure 2 is a schematic diagram of the surface of the print head 24 facing the medium P. As shown in Figure 2, the print head 24 has a plurality of nozzle rows. In this embodiment, as an example, the print head 24 has four nozzle rows 43A, 43B, 43C, and 43D. Nozzle row 43A is a nozzle row consisting of a series of nozzles 23A that eject, for example, cyan ink. Nozzle row 43B is a nozzle row consisting of a series of nozzles 23B that eject, for example, magenta ink. Nozzle row 43C is a nozzle row consisting of a series of nozzles 23C that eject, for example, yellow ink. Nozzle row 43D is a nozzle row consisting of a series of nozzles 23D that eject, for example, black ink.

[0013] In this disclosure, when referring to nozzle rows 43A, 43B, 43C, and 43D without making any particular distinction, they will be referred to as nozzle row 43. Similarly, when referring to nozzles 23A, 23B, 23C, and 23D without making any particular distinction, they will be referred to as nozzle 23.

[0014] A series of nozzles 23 constituting a single nozzle row are arranged in a direction perpendicular to the main scanning direction, that is, in the transport direction of the medium P. In this embodiment, as an example, the print head 24 has four nozzle rows, but the print head 24 may have any number of nozzle rows, and is not limited to four. For example, the print head 24 may have six nozzle rows that eject ink (liquid) of different colors. Furthermore, in the print head 24, the multiple nozzle rows only need to be arranged in the main scanning direction, and the arrangement of colors ejected from the nozzle rows is not limited to the example described above.

[0015] Each nozzle 23 is connected to a liquid (ink) flow path, such as a liquid chamber. The liquid chamber contracts due to the drive of a piezoelectric element controlled by the control unit 70, causing the liquid (ink) to be ejected. That is, when liquid is ejected from a nozzle 23, the flow path connected to that nozzle deforms. This deformation can affect the flow paths connected to other nozzles, and thus affect the ejection of liquid (ink) from those other nozzles. In other words, a phenomenon called crosstalk may occur. In particular, during flushing, large dot droplets are ejected simultaneously from a series of nozzles constituting a nozzle row, so the crosstalk effect on other nozzle rows can be significant. More specifically, flushing from one nozzle row affects other nozzle rows located next to it through crosstalk. Note that "large dot" refers to a relatively large dot, for example, when it is possible to eject multiple dots of different sizes by controlling the drive pulse that drives the piezoelectric element. In the following explanation, a nozzle row affected by crosstalk from one nozzle row will be referred to as the affected nozzle row. Also, a nozzle row that affects other nozzle rows through crosstalk will be referred to as the influencing nozzle row. In this embodiment, there is one affected nozzle row for each influencing nozzle row. Specifically, nozzle row 43A and nozzle row 43B mutually influence or are influenced by each other in a crosstalk relationship. Also, nozzle row 43C and nozzle row 43D mutually influence or are influenced by each other in a crosstalk relationship. That is, nozzle row 43A and nozzle row 43B constitute a nozzle row group in which crosstalk occurs, and nozzle row 43C and nozzle row 43D constitute a nozzle row group in which crosstalk occurs. Therefore, in this embodiment, no crosstalk occurs between nozzle row 43B and nozzle row 43C. More specifically, in this embodiment, the following crosstalk relationships exist: Crosstalk from nozzle row 43A affects only nozzle row 43B, and crosstalk from nozzle row 43B affects only nozzle row 43A. Crosstalk caused by nozzle row 43C affects only nozzle row 43D, and crosstalk caused by nozzle row 43D affects only nozzle row 43C.Thus, in this embodiment, the nozzle row group having a crosstalk relationship is composed only of pairs of two adjacent nozzle rows.

[0016] As described above, the reason why the nozzle row group having a crosstalk relationship is composed only of pairs of two adjacent nozzle rows is, for example, that in the print head 24, the structure of the flow path for the nozzle 23 is arranged as shown in FIG. 3. FIG. 3 is a schematic diagram showing an example of the range where the nozzle row 43 and the flow path for the nozzle row exist. In the example shown in FIG. 3, each flow path for each nozzle 23A constituting the nozzle row 43A exists in the range Ra, and each flow path for each nozzle 23B constituting the nozzle row 43B exists in the range Rb. Further, each flow path for each nozzle 23C constituting the nozzle row 43C exists in the range Rc, and each flow path for each nozzle 23D constituting the nozzle row 43D exists in the range Rd. As shown in FIG. 3, the range Ra and the range Rb are adjacent to each other, and the range Rc and the range Rd are adjacent to each other, but the range Rb and the range Rc are separated from each other. Thus, each nozzle 23 may be unevenly distributed on one side instead of being in the center of the flow path (liquid chamber). For example, the flow path for the nozzle 23A and the flow path for the nozzle 23B may be configured to be line-symmetric with the conveyance direction as the axis of symmetry. Similarly, the flow path for the nozzle 23C and the flow path for the nozzle 23D may be configured to be line-symmetric with the conveyance direction as the axis of symmetry. When the flow paths are arranged in this way, etc., the nozzle row group having a crosstalk relationship is composed only of pairs of two adjacent nozzle rows, but for other reasons, the nozzle row group having a crosstalk relationship may be composed only of pairs of two adjacent nozzle rows. For example, since two rows of nozzle rows are formed on one head chip, the nozzle row group having a crosstalk relationship may be composed only of pairs of two adjacent nozzle rows.

[0017] Next, the platen 51 will be described. Figure 4 is a schematic diagram showing an example of the configuration of the platen 51. More specifically, Figure 4 is a schematic diagram of the surface on which the medium P is placed on the platen 51. As shown in Figure 4, the platen 51 has liquid receiving areas 52AR, 52AL, 52BR, and 52BL for receiving liquid (ink) ejected from the print head 24. Hereafter, when referring to the liquid receiving areas 52AR, 52AL, 52BR, and 52BL without making any particular distinction, they will be referred to as the liquid receiving area 52. The liquid receiving area 52 receives ink ejected by flushing, which will be described later, and also receives ink that extends beyond the width of the medium P when performing so-called borderless printing, where a printing area without margins is set on the medium P. In order to prevent the liquid ejected into the liquid receiving area 52 from adhering to the medium P when the edge of the medium P sags toward the platen 51 due to its own weight, the liquid receiving area 52 may be formed as a groove. The liquid receiving region 52 may be provided with an absorbent material made of a material such as sponge or felt that can absorb liquid. Although not shown in Figure 4, the medium P is supported by a plurality of ribs (see rib 53 in Figure 6) provided on the surface of the platen 51.

[0018] The platen 51 is capable of holding multiple types of media P of different sizes used in the printing apparatus 20. In the example shown in Figure 4, the printing apparatus 20 can print on two different sizes of media P, for example. The liquid receiving area 52 is positioned corresponding to the position of the end of the media P used in the main scanning direction. The liquid receiving area 52 is positioned to include at least a predetermined area outside the end of the media P in the main scanning direction, but may also be positioned to include an area inside the said end of the media P, as shown in Figure 4. The reason for positioning the liquid receiving area 52 to include the area inside the said end of the media P is, for example, to prevent errors in the position of the media P.

[0019] The liquid receiving area 52 is provided for each size of the medium P. In the example shown in FIG. 4, the liquid receiving area 52AR is the liquid receiving area 52 provided on one end side of the medium P of the first size, and the liquid receiving area 52AL is the liquid receiving area 52 provided on the other end side of the medium P of the first size. Similarly, the liquid receiving area 52BR is the liquid receiving area 52 provided on one end side of the medium P of the second size, and the liquid receiving area 52BL is the liquid receiving area 52 provided on the other end side of the medium P of the second size. Thus, when there are a plurality of sizes of the medium P used in the printing apparatus 20, the number of pairs of the liquid receiving areas 52 is plural, but when there is only one type of size of the medium P used in the printing apparatus 20, the number of pairs of the liquid receiving areas 52 may be one. Also, in the present embodiment, the liquid receiving areas 52 are provided on both sides of the medium P, but the liquid receiving areas 52 may be provided on only one of the sides of the medium P.

[0020] The control unit 70 (see FIG. 1) includes a processor 71, a memory 72, and an interface (I / F) 73. Thus, the control unit 70 has functions as a computer.

[0021] The memory 72 is constituted by, for example, a combination of a volatile memory and a non-volatile memory. The memory 72 is used to store programs executed by the processor 71, data used for various processes, and the like. The position and size of the liquid receiving area 52 may be stored in the memory 72. Also, print data sent from the user PC 10, which is a general-purpose personal computer, via the interface 73 is stored in the memory 72.

[0022] The processor 71 reads a program from memory 72 and executes it. This allows the processor 71 to perform various control processes for the printing device 20. The processor 71 may be, for example, a microprocessor, an MPU (Micro Processor Unit), or a CPU (Central Processing Unit). The processor 71 may also include multiple processors.

[0023] Based on the processing by the processor 71, the control unit 70 outputs drive signals to the print head 24, drive signals to the drive motor 33, drive signals to the carriage motor 34a, etc., to control the printing operation.

[0024] When the control unit 70 receives print data, which is dot data generated by, for example, the user PC 10, along with various print settings, along with a print command, it expands the print data into a print buffer area provided in the memory 72. The print settings may include the size of the medium P. The control unit 70 then controls the drive motor 33 to rotate the paper feed roller 35 and transport the medium P onto the platen 51. The control unit 70 then controls the carriage motor 34a to move the carriage 22 in the main scanning direction, while simultaneously discharging liquid from each nozzle 23 of the print head 24 to form dots on the medium P. This forms an image on the medium P.

[0025] Here, the flushing performed in this embodiment will be described. In the printing apparatus 20 according to this embodiment, when the print head 24 (carriage 22) is moved in any one direction in the main scanning direction, both the formation of an image on the medium P and the flushing of the nozzle 23 in the liquid receiving area 52 are performed. Hereafter, the movement of the print head 24 (carriage 22) in any one direction in the main scanning direction will be referred to as a pass, and one movement of the print head 24 (carriage 22) in any one direction in the main scanning direction will be referred to as one pass (one-pass operation).

[0026] Figure 5 is a schematic diagram showing liquid ejection data for performing image formation and flushing in a single pass. As shown in Figure 5, the control unit 70 generates flushing data D2, which is control data for ejecting liquid from the nozzles 23 into a liquid receiving area 52 corresponding to the size of the medium P. The flushing data D2 is, for example, data that instructs the print head 24 to perform flushing by ejecting large dot ink droplets from all nozzles 23 constituting a single nozzle row 43, and also includes information to control the nozzle row to be flushed and the timing of the execution of flushing. The nozzle row to be flushed refers to the nozzle row on which flushing is performed. The control unit 70 generates liquid ejection data D3, which controls the ejection of liquid in a single pass, by adding the flushing data D2 to the print data D1 for one pass. In this embodiment, borderless printing is possible, and therefore, as shown in Figure 5, the width of the area in the main scanning direction where liquid ejection based on the print data D1 is performed is greater than or equal to the width of the medium P. However, the printing device 20 may perform so-called bordered printing, where a margin exists around the edge of the medium P. In this case, the width of the area in the main scanning direction where the liquid based on the print data is ejected will be less than the width of the medium P.

[0027] The control unit 70 executes a single-pass printing process while moving the carriage 22 based on the liquid ejection data. This ensures that both image formation on the medium P and flushing of the nozzle 23 in the liquid receiving area 52 are performed in a single pass. Specifically, the control unit 70 performs both printing ejection (first ejection), which is the ejection of liquid to form an image on the medium P, and flushing ejection (second ejection), which is the ejection of liquid for flushing in a predetermined area outside the edge of the medium P in the main scanning direction, during a single movement of the carriage 22 in the main scanning direction. This operation allows for efficient image formation and flushing. In particular, since flushing is performed near the edge of the medium P, the amount of carriage 22 movement can be reduced compared to when flushing is performed at a location far from the medium P. Therefore, performing flushing near the edge of the medium P can improve the throughput of image formation.

[0028] However, the inventors found that when the above-described flushing is performed, the quality of the image printed on the medium P may deteriorate due to the effects of crosstalk. Figure 6 is a schematic diagram showing the flushing according to the comparative example. Figure 6 shows how flushing is performed in the liquid receiving area 52 at the right end of the medium P. When printing is performed, the medium P rests on a plurality of ribs 53 provided on the surface of the platen 51, as shown in Figure 6. A liquid receiving area 52 is also provided below the outer edge of the medium P. The position in which the liquid receiving area 52 is located can also be described as follows. The liquid receiving area 52 is located such that at least a part of the carriage 22, which mounts the print head 24 that ejects liquid for flushing toward the liquid receiving area 52, overlaps with the medium P when viewed from the direction of liquid ejection (Z direction in the figure) at the time of flushing. Furthermore, in the print head 24, as described above, if nozzle row 43A (nozzle row 43B) is the nozzle row to be flushed, then nozzle row 43B (nozzle row 43A) is the affected nozzle row. Also, if nozzle row 43C (nozzle row 43D) is the nozzle row to be flushed, then nozzle row 43D (nozzle row 43C) is the affected nozzle row.

[0029] Assuming that the print head 24 is in the position shown in Figure 6, and that nozzle row 43D is performing flushing liquid ejection, i.e., the flushing ejection described above, and that at the same time, nozzle rows 43A to 43C are performing printing liquid ejection, i.e., the printing ejection described above, to print an image based on print data onto the medium P, the carriage 22 may be understood as moving to the right or to the left. As described above, when nozzle row 43D performs flushing, the liquid ejection from nozzle row 43C is affected by crosstalk. As a result, the shape of the droplets from nozzle row 43C that land at position X1 in the main scanning direction changes from the ideal shape. Consequently, at position X1 in the main scanning direction, which is the landing position of the droplets ejected from nozzle row 43C, streaks extending in a direction perpendicular to the main scanning direction (transport direction) appear on the medium P. As a result, the quality of the image printed on the medium P deteriorates. Although Figure 6 illustrates the example of flashing occurring at the right edge of medium P, similar image degradation can occur when flashing occurs on the left side of medium P.

[0030] Therefore, in this embodiment, the control unit 70 performs flushing at a timing that does not cause deterioration of the image quality of the image printed on the medium P, even if crosstalk occurs. Figure 7 is a schematic diagram showing the flushing according to this embodiment. In Figure 7, as in Figure 6, the flushing is performed in the liquid receiving area 52 at the right end of the medium P. As shown in Figure 7, the control unit 70 performs flushing on the nozzle row to be flushed (nozzle row 43C in Figure 7) at a timing when the affected nozzle row (nozzle row 43D in Figure 7), which is affected by the discharge of liquid due to the flushing performed by the nozzle row to be flushed, is located outside the medium P. In detail, the control unit 70 performs flushing at a timing when the affected nozzle row (nozzle row 43D in Figure 7) is located outside the medium P, and at least a part of the carriage 22 is in a position that overlaps with the medium P when viewed from the direction of liquid discharge. By performing flushing in this manner, it is possible to suppress deterioration of image quality due to crosstalk associated with flushing. More specifically, the control unit 70 performs flushing at the timing described above, and when the row of nozzles to be flushed is directly above the liquid receiving area 52.

[0031] Furthermore, the position of the affected nozzle row may be outside the image-forming area, in addition to being outside the medium P, as a condition for the timing of flushing. Here, the image-forming area is the area in the main scanning direction in which print ejection (first ejection), which is the ejection of liquid for forming an image on the medium P, is performed. In the case of borderless printing, the width of the image-forming area is greater than the width of the medium P. If the position of the affected nozzle row is outside the medium P and outside the image-forming area at the time of flushing, the position of the affected nozzle row can be moved further away from the medium P. This makes it possible to more reliably prevent deterioration of the image quality formed on the medium P. Thus, the control unit 70 may perform flushing at a timing when the affected nozzle row is located outside the image-forming area and the medium P, and at least a part of the carriage 22 is in a position that overlaps with the medium P when viewed from the direction of liquid ejection.

[0032] In this embodiment, the control unit 70 sequentially selects one of the multiple nozzle rows 43 of the print head 24 as the nozzle row to be flushed. For example, in Figure 7, when the carriage 22 is moving to the right, the control unit 70 selects the nozzles to be flushed in the order of nozzle row 43C, then nozzle row 43A. Also, in Figure 7, when the carriage 22 is moving to the left, the control unit 70 selects the nozzles to be flushed in the order of nozzle row 43A, then nozzle row 43C. In other words, for flushing the first end side of the medium P (the right end side of the medium P shown in Figure 7), the nozzle rows (nozzle rows 43A, 43C) located on the second end side of the medium P (the left end side of the medium P) among the pairs of nozzle rows that are in a crosstalk relationship are sequentially selected in the opposite direction to the movement direction of the carriage 22. Furthermore, flushing may be performed only when the carriage 22 is moving to the right, or only when the carriage 22 is moving to the left, or in both cases when the carriage 22 is moving to the right and when the carriage 22 is moving to the left.

[0033] The operation when flushing is performed in the liquid receiving area 52 at the right end of the medium P has been described, but the same applies when flushing is performed in the liquid receiving area 52 at the left end of the medium P. Figure 8 is a schematic diagram showing flushing performed in the liquid receiving area 52 at the left end of the medium P. As shown in Figure 8, the control unit 70 performs flushing on the nozzle row to be flushed (nozzle row 43B in Figure 8) when the affected nozzle row (nozzle row 43A in Figure 8) is located outside the medium P and at least a part of the carriage 22 is in a position overlapping with the medium P when viewed from the direction of liquid discharge. In Figure 8, when the carriage 22 is moving to the right, the control unit 70 selects the nozzles to be flushed in the order of nozzle row 43D, then nozzle row 43B. Also in Figure 8, when the carriage 22 is moving to the left, the control unit 70 selects the nozzles to be flushed in the order of nozzle row 43B, then nozzle row 43D. In other words, during flushing at the second end of medium P (the left end of medium P as shown in Figure 8), each nozzle row (nozzle rows 43B, 43D) located at the first end of medium P (the right end of medium P) among the pairs of nozzle rows in a crosstalk relationship is selected in order according to the opposite direction of movement of the carriage 22. Note that even during flushing at the left end of medium P, flushing may be performed only when the carriage 22 is moving to the right, or only when the carriage 22 is moving to the left, or in both cases when the carriage 22 is moving to the right and when the carriage 22 is moving to the left.

[0034] Thus, in this embodiment, the discharge of liquid for flushing is performed in a first region (liquid receiving region 52 on the right side of the medium P) outside the first end (right end) in the main scanning direction of the medium P, and in a second region (liquid receiving region 52 on the left side of the medium P) outside the second end (left end) in the main scanning direction of the medium P. Furthermore, in the flushing in the first region (liquid receiving region 52 on the right side of the medium P), one of the pair of nozzle rows in a crosstalk relationship (nozzle rows 43A, 43C) is used as the nozzle row to be flushed. Similarly, in the flushing in the second region (liquid receiving region 52 on the left side of the medium P), the other of the pair of nozzle rows in a crosstalk relationship (nozzle rows 43B, 43D) is used as the nozzle row to be flushed. Therefore, flushing can be performed on all nozzle rows.

[0035] As shown in Figures 7 and 8, in this embodiment, among the pairs of nozzle rows that are in a crosstalk relationship, only the nozzle row closer to the edge of the medium P at the timing of the flushing described above is selected as the nozzle row to be flushed, and flushing is performed. That is, in the example shown in Figure 7, of the pair of nozzle rows 43C and 43D that are in a crosstalk relationship, only nozzle row 43C, which is closer to the edge of the medium P, is selected as the nozzle row to be flushed, and flushing is performed. Similarly, in the example shown in Figure 8, of the pair of nozzle rows 43A and 43B that are in a crosstalk relationship, only nozzle row 43B, which is closer to the edge of the medium P, is selected as the nozzle row to be flushed, and flushing is performed. This makes it possible to narrow the width of the liquid receiving area 52 provided at the edge of the medium P in the main scanning direction, thereby improving the design freedom of the platen 51.

[0036] Next, the operation of the printing device 20 will be explained with reference to a flowchart. Figure 9 is a flowchart showing an example of the operation flow of the printing device 20.

[0037] In step S100, the control unit 70 acquires print data for printing an image onto the medium P. In this embodiment, the control unit 70 acquires print data for borderless printing on the medium P, for example.

[0038] Next, in step S101, the control unit 70 performs the paper feeding process. That is, the control unit 70 controls the drive motor 33 so that the medium P is fed onto the platen 51.

[0039] Next, in step S102, the control unit 70 generates the flashing data described above and generates liquid ejection data that controls the ejection of liquid in one pass based on the print data and the generated flashing data. That is, the control unit 70 generates liquid ejection data for performing image formation and flashing on the medium P in one pass.

[0040] Next, in step S103, the control unit 70 moves the carriage 22 based on the generated liquid discharge data and executes a printing process for one pass. This prints an image onto the medium P and flushes the edges of the medium P. At this time, the control unit 70 performs flushing of the nozzles to be flushed at the timing described above.

[0041] Next, in step S104, the control unit 70 determines whether or not there is print data to be printed in the next pass. If there is print data for the next pass, in step S105, the control unit 70 transports a predetermined amount of the medium P for printing in the next pass, and the process returns to step S102. On the other hand, if in step S104 it is determined that there is no data to be printed in the next pass, in step S106, the control unit 70 controls the drive motor 33 so that the medium P is ejected from the platen 51, and the process ends.

[0042] The embodiments have been described above. In the printing apparatus 20, as described above, flashing is performed when the affected nozzle row is located outside the medium P and at least a part of the carriage 22 is positioned to cover the medium P. By performing flashing at such a timing, it is possible to suppress the deterioration of image quality formed on the medium P due to crosstalk associated with flashing. In addition, in the configuration of the print head 24 according to this embodiment, the affected nozzle row is a nozzle row located next to the nozzle row to be flashed. Even if the printing apparatus 20 has such a configuration, flashing is performed at the timing described above, so the deterioration of image quality due to crosstalk associated with flashing can be suppressed. Therefore, even in print heads such as the one shown in Figure 3, or print heads in which two rows of nozzles are formed on a single head chip, the deterioration of image quality due to crosstalk associated with flashing can be suppressed. Therefore, the design flexibility of the print head can be improved. Furthermore, in the printing apparatus 20, flashing is performed at the timing described above when borderless printing is performed, that is, when the image formation area is greater than or equal to the width of the medium P in the main scanning direction. In borderless printing, printing to form the image is performed at a position close to the liquid receiving area 52 where flushing takes place. Therefore, borderless printing is prone to image quality degradation due to crosstalk. However, in this embodiment, since flushing is performed at the timing described above, image quality degradation can be suppressed even when such printing is performed.

[0043] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, in the embodiments described above, the affected nozzle row was only one nozzle row located on one side of the nozzle row to be flushed, but the affected nozzle row may be two nozzle rows located on both sides of the nozzle row to be flushed. In this case as well, as shown in Figure 10, flushing should be performed on the nozzle row to be flushed when each of the affected nozzle rows is located outside the medium P. This will be explained with reference to Figure 10. Note that matters similar to those described in the embodiments will be omitted as appropriate. Figure 10 is a schematic diagram showing flushing performed when the affected nozzle rows are two nozzle rows located on both sides of the nozzle row to be flushed. In Figure 10, as an example, flushing is performed in the liquid receiving region 52 at the right end of the medium P. As shown in Figure 10, the control unit 70 performs flushing on the nozzle row to be flushed (nozzle row 43C in Figure 10) at the timing when the affected nozzle rows (nozzle rows 43B and 43D in Figure 10), which are affected by the liquid discharge due to flushing by the nozzle row to be flushed, are located outside the medium P. More specifically, the control unit 70 performs flushing at the timing when the affected nozzle rows (nozzle rows 43B and 43D in Figure 10) are located outside the medium P, and at least a portion of the carriage 22 is positioned to overlap with the medium P when viewed from the direction of liquid discharge. By performing flushing in this manner, even if the nozzle rows on both sides of the nozzle row to be flushed are affected nozzle rows, it is possible to suppress the deterioration of image quality due to crosstalk associated with flushing.

[0044] Furthermore, even if the nozzle rows on both sides of the nozzle row to be flushed are affected nozzle rows, the control unit 70 may sequentially select one of the multiple nozzle rows 43 of the print head 24 as the nozzle row to be flushed. For example, in Figure 10, when the carriage 22 is moving to the right, the control unit 70 may select the nozzles to be flushed in the order of nozzle row 43D, 43C, 43B, and 43A. Also, in Figure 10, when the carriage 22 is moving to the left, the control unit 70 may select the nozzles to be flushed in the order of nozzle row 43A, 43B, 43C, and 43D. In other words, for flushing the first end side of the medium P (the right end side of the medium P shown in Figure 10), each nozzle row 43 mounted on the print head 24 may be selected sequentially in the opposite direction to the direction of movement of the carriage 22. Furthermore, flushing may be performed only when the carriage 22 is moving to the right, or only when the carriage 22 is moving to the left, or both when the carriage 22 is moving to the right and when the carriage 22 is moving to the left. The above describes the operation when flushing is performed in the liquid receiving area 52 at the right end of the medium P, but the same applies when flushing is performed in the liquid receiving area 52 at the left end of the medium P. In addition, even when the nozzle rows on both sides of the nozzle row to be flushed are affected nozzle rows, the condition for the timing of flushing may be that the position of the affected nozzle rows is outside the medium P, as well as that the position of the affected nozzle rows is outside the image forming range.

[0045] Furthermore, in this disclosure, a program includes a set of instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more of the functions described in the embodiments. A program may be stored on a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, 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® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. A program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include temporary computer-readable medium or a communication medium that includes electrical, optical, acoustic or other forms of propagating signals.

[0046] Some or all of the above embodiments and modifications may also be described as follows, but are not limited to the following: (Note 1) A printing method using a printing apparatus comprising: a print head having multiple nozzle rows; a carriage on which the print head is mounted; and a control unit that controls the discharge of liquid from the nozzle rows and the movement of the carriage in the main scanning direction, A first discharge, which is the discharge of the liquid for forming an image on the medium, and a second discharge, which is the discharge of the liquid for flushing in a predetermined area outside the end of the medium in the main scanning direction, are performed during one pass of the carriage. The second discharge is performed for the nozzle row to be flushed, which is the nozzle row on which the second discharge is performed, at a timing when the affected nozzle row is located outside the medium and at least a portion of the carriage is in a position overlapping with the medium when viewed from the direction of liquid discharge. The aforementioned one-pass operation is an operation in which the carriage moves once in one of the directions of the main scanning direction, The affected nozzle row is the nozzle row whose discharge of the liquid is affected by the execution of the second discharge by the flushing target nozzle row. Printing method. (Note 2) The second discharge is performed for the flashing target nozzle row when the affected nozzle row is located outside the image forming range, which is the range of the main scanning direction in which the first discharge is performed. Printing method as described in Appendix 1. (Note 3) The affected nozzle row is the nozzle row located next to the nozzle row to be flushed. Printing method as described in Appendix 1 or 2. (Note 4) The plurality of nozzle rows include a first nozzle row and a second nozzle row arranged in the main scanning direction, If the first nozzle row is the nozzle row to be flushed, then the second nozzle row is the affected nozzle row, If the second nozzle row is the nozzle row to be flushed, then the first nozzle row is the affected nozzle row, Of the first and second nozzle rows, only those nozzles closer to the end of the medium at the aforementioned timing are designated as the nozzle row to be flushed, and the second discharge is performed. The printing method described in any one of the items 1 to 3 in the appendix. (Note 5) The second discharge is performed in a first region outside the first end of the medium in the main scanning direction and a second region outside the second end of the medium in the main scanning direction. In the second discharge in the first region, the second nozzle row is treated as the nozzle row to be flushed, and the second discharge is performed. In the second discharge in the second region, the first nozzle row is used as the nozzle row to be flushed, and the second discharge is performed. Printing method as described in Appendix 4. (Note 6) If the image forming range, which is the range in the main scanning direction in which the first ejection is performed, is greater than or equal to the width of the medium in the main scanning direction, then the second ejection for the flushing target nozzle row is performed at the timing described above. The printing method described in any one of the items 1 to 5 in the appendix. (Note 7) A print head having multiple nozzle rows, A carriage equipped with the aforementioned print head, A control unit that controls the discharge of liquid from the nozzle row and the movement of the carriage in the main scanning direction, It has, The control unit performs a first discharge, which is the discharge of the liquid for forming an image on the medium, and a second discharge, which is the discharge of the liquid for flushing in a predetermined area outside the end of the medium in the main scanning direction, during one pass of the carriage. The second discharge is performed for the nozzle row to be flushed, which is the nozzle row on which the second discharge is performed, at a timing when the affected nozzle row is located outside the medium and at least a portion of the carriage is in a position overlapping with the medium when viewed from the direction of liquid discharge. The aforementioned one-pass operation is an operation in which the carriage moves once in one of the directions of the main scanning direction, The affected nozzle row is the nozzle row whose discharge of the liquid is affected by the execution of the second discharge by the flushing target nozzle row. Printing device. [Explanation of symbols]

[0047] 10...User PC, 20...Printing device, 21...Printer mechanism, 21a...Mechanical frame, 22...Carriage, 23...Nozzle, 24...Print head, 26...Ink cartridge, 28...Guide, 31...Paper feeding mechanism, 32...Carriage belt, 33...Drive motor, 34a...Carriage motor, 34b...Driven roller, 35...Paper feeding roller, 43...Nozzle row, 51...Platen, 52...Liquid receiving area, 53...Rib, 70...Control unit, 71...Processor, 72...Memory, 73...Interface, D1...Print data, D2...Flushing data, D3...Liquid ejection data, P...Media, Ra...Range, Rb...Range, Rc...Range, Rd...Range, X1...Position

Claims

1. A printing method using a printing apparatus comprising: a print head having multiple nozzle rows; a carriage on which the print head is mounted; and a control unit that controls the discharge of liquid from the nozzle rows and the movement of the carriage in the main scanning direction, A first discharge, which is the discharge of the liquid for forming an image on the medium, and a second discharge, which is the discharge of the liquid for flushing in a predetermined area outside the end of the medium in the main scanning direction, are performed during one pass of the carriage. The second discharge is performed for the nozzle row to be flushed, which is the nozzle row on which the second discharge is performed, at a timing when the affected nozzle row is located outside the medium and at least a portion of the carriage is in a position overlapping with the medium when viewed from the direction of liquid discharge. The aforementioned one-pass operation is an operation in which the carriage moves once in one of the directions of the main scanning direction. The affected nozzle row is the nozzle row whose discharge of the liquid is affected by the execution of the second discharge by the flushing target nozzle row. Printing method.

2. The second discharge is performed for the flashing target nozzle row when the affected nozzle row is located outside the image forming range, which is the range of the main scanning direction in which the first discharge is performed. The printing method according to claim 1.

3. The affected nozzle row is the nozzle row located next to the nozzle row to be flushed. The printing method according to claim 1 or 2.

4. The plurality of nozzle rows include a first nozzle row and a second nozzle row arranged in the main scanning direction, If the first nozzle row is the nozzle row to be flushed, then the second nozzle row is the affected nozzle row, If the second nozzle row is the nozzle row to be flushed, then the first nozzle row is the affected nozzle row, Of the first and second nozzle rows, only those nozzles closer to the end of the medium at the aforementioned timing are designated as the nozzle row to be flushed, and the second discharge is performed. The printing method according to claim 1.

5. The second discharge is performed in a first region outside the first end of the medium in the main scanning direction and a second region outside the second end of the medium in the main scanning direction. In the second discharge in the first region, the second nozzle row is used as the nozzle row to be flushed, and the second discharge is performed. In the second discharge in the second region, the first nozzle row is used as the nozzle row to be flushed, and the second discharge is performed. The printing method according to claim 4.

6. If the image forming range, which is the range in the main scanning direction in which the first ejection is performed, is greater than or equal to the width of the medium in the main scanning direction, then the second ejection for the flushing target nozzle row is performed at the timing described above. The printing method according to claim 1 or 2.

7. A print head having multiple nozzle rows, A carriage equipped with the aforementioned print head, A control unit that controls the discharge of liquid from the nozzle row and the movement of the carriage in the main scanning direction, It has, The control unit performs a first discharge, which is the discharge of the liquid for forming an image on the medium, and a second discharge, which is the discharge of the liquid for flushing in a predetermined area outside the end of the medium in the main scanning direction, during one pass of the carriage. The second discharge is performed for the nozzle row to be flushed, which is the nozzle row on which the second discharge is performed, at a timing when the affected nozzle row is located outside the medium and at least a portion of the carriage is in a position overlapping with the medium when viewed from the direction of liquid discharge. The aforementioned one-pass operation is an operation in which the carriage moves once in one of the directions of the main scanning direction. The affected nozzle row is the nozzle row whose discharge of the liquid is affected by the execution of the second discharge by the flushing target nozzle row. Printing device.

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