Printing device

Abstract

To provide a printing device that enables printing to be performed at a higher speed while suppressing an image quality from deteriorating.SOLUTION: A printing device comprises a head, a scanning device and a control part, where a plurality of nozzles have a first nozzle group of a plurality of nozzles arranged in an intersecting, and a second nozzle group of a plurality of nozzles arranged in a first direction closer to a scanning direction than the first nozzle group and arranged in the intersecting direction. The control part, when making the nozzles discharge ink while moving the head in the scanning direction to print an image on a printing medium, obtains nozzle information for specifying the nozzle group, of the first nozzle group and the second nozzle group, which is made to discharge ink, then obtains margin information concerning a margin between an end of the printing medium and the image in the scanning direction, and prints the image on the printing medium by making the nozzle group based on the nozzle information discharge ink, while moving the head in the scanning direction at a first speed or a second speed higher than the first speed, on the basis of the nozzle information and the margin information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a printing device. [Background technology]

[0002] In the image recording device of Patent Document 1, a conventional printing device, an image is recorded on a recording medium while moving an image recording head in a scanning direction at a low or high speed. When this image recording device records an image while moving at high speed based on print data, it obtains a comparison result to determine whether the image recording head will record an image during a speed change period from when the image recording head starts moving until the image recording head reaches a high speed. Then, based on this comparison result, the image recording device determines whether the moving speed of the image recording head when actually recording an image should be low or high. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-49707 Summary of the Invention [Problem to be solved by the invention]

[0004] In the image recording device, the image recording head is moved at high speed to increase the image recording speed, while the image recording head is moved at low speed to prevent degradation of the image quality of the recorded image.

[0005] In such an image recording device, an image may be recorded using ink of multiple colors. In this case, the image recording head has multiple nozzle groups, each consisting of multiple nozzles that eject ink, arranged in the scanning direction for each color. The inventors have discovered that when an image is recorded based on print data using such an image recording device, even if the image recording head movement speed is determined to be low when controlled in accordance with the image recording device of Patent Document 1, the image recording head movement speed may be increased depending on the color of the image.

[0006] The present invention has been made to solve such problems, and has as its object to provide a printing device that can increase printing speed while suppressing degradation of image quality. [Means for solving the problem]

[0007] A printing device according to one aspect of the present invention includes a head having a plurality of nozzles that eject ink onto a printing medium, a scanning device that moves the head in a first scanning direction and a second scanning direction opposite to the first scanning direction, and a control unit, wherein the plurality of nozzles include a first nozzle group that is a plurality of nozzles aligned in an intersecting direction that intersects the scanning direction, and a second nozzle group that is a plurality of nozzles that is positioned further in the first scanning direction than the first nozzle group and aligned in the intersecting direction, and the control unit acquires nozzle information that specifies which of the first nozzle group and the second nozzle group will eject the ink from when printing an image on the printing medium by ejecting the ink from the nozzles while moving the head in the scanning direction, acquires margin information regarding a margin between an edge of the printing medium in the scanning direction and the image, and moves the head in the scanning direction at a first speed or a second speed faster than the first speed based on the nozzle information and the margin information, while ejecting the ink from the nozzle group based on the nozzle information to print the image on the printing medium. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a printing device that can increase printing speed while suppressing degradation of image quality.

[0009] The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a printing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically illustrating the underside of the head. [Figure 3] FIG. 3 is a block diagram showing the functional configuration of the printing device. [Figure 4] FIG. 4 is a diagram schematically showing dots formed in a printing area of ​​a printing medium. [Figure 5] Figure 5(a) is a graph showing the relationship between head position and velocity when the head moves to the right at a constant speed of a first velocity, and Figure 5(b) is a graph showing the relationship between head position and velocity when the head moves to the left at a constant speed of a first velocity. [Figure 6] Figure 6(a) is a graph showing the relationship between head position and velocity when the head moves to the right at a constant speed of the second velocity, and Figure 6(b) is a graph showing the relationship between head position and velocity when the head moves to the left at a constant speed of the second velocity. [Figure 7] FIG. 7 is a flowchart showing an example of a method for determining the moving speed of the head. [Figure 8] FIG. 8 is a flowchart showing an example of a method for determining the head movement speed in monochrome printing. [Figure 9] FIG. 9 is a flowchart showing an example of a method for determining the moving speed of the head in color printing. [Figure 10] FIG. 10 is a flowchart showing an example of a method for determining the moving speed of the head in full-color printing. [Figure 11]FIG. 11 is a flowchart showing an example of a method for determining the moving speed of the head in the printing device according to the first modification of the present invention. [Figure 12] FIG. 12 is a flowchart showing an example of a method for determining the moving speed of the head in a printing device according to the second modification of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding elements will be designated by the same reference numerals throughout the drawings, and redundant description thereof will be omitted.

[0012] (Embodiment) <Printing device configuration> As shown in Fig. 1, a printing device 10 according to an embodiment of the present invention is a device that ejects ink from a head 20 onto a printing medium A and prints an image on the printing medium A using the ink. Below, an example in which the printing device 10 is applied to an inkjet printer will be described, but the printing device 10 is not limited to this. The printing medium A is a sheet of paper, cloth, or the like.

[0013] The printing device 10 is a serial head type and includes a head 20, a platen 11, a conveying device 30, a scanning device 40, tanks 12K, 12Y, 12C, and 12M, an input device 13, and a control unit 50. The first scanning direction in which the scanning device 40 moves the head 20 is referred to as the left, and the second scanning direction opposite the first scanning direction is referred to as the right. The intersecting direction (e.g., perpendicular to) the scanning direction is referred to as the front-to-rear direction. The direction perpendicular to the scanning direction and the intersecting direction is referred to as the up-to-down direction. However, the layout of the printing device 10 is not limited to this. The head 20 and the control unit 50 will be described in detail below.

[0014] The platen 11 has a flat upper surface and defines the distance between the print medium A placed on the upper surface and the lower surface of the head 20 provided opposite to the print medium A. In the left-right direction, the width of the platen 11 is wider than the width of the print medium A placed on the upper surface of the platen 11.

[0015] The transport device 30 has, for example, two transport rollers 31 and a transport motor 32 (FIG. 3). The two transport rollers 31 are arranged parallel to each other in the front-to-rear direction, with the platen 11 sandwiched between them. The transport roller 31 has a central axis extending in the left-to-right direction and is connected to the transport motor 32. The transport roller 31 is rotated by the drive of the transport motor 32, transporting the print medium A in the front-to-rear direction on the platen 11.

[0016] The scanning device 40 includes a carriage 41, two guide rails 42, a scanning motor 43 (FIG. 3), etc. The carriage 41 carries the head 20, is supported by the two guide rails 42, and is fixed to an endless belt. The two guide rails 42 extend in the left-right direction above the platen 11, sandwiching the underside of the head 20 between them in the front-rear direction. When the scanning motor 43 is driven, the connected endless belt runs, and the carriage 41 moves back and forth in the left-right direction along the guide rails 42.

[0017] Tanks 12K, 12Y, 12C, and 12M are, for example, removable cartridges, and are provided for each type of ink. For example, tank 12K stores black ink, tank 12Y stores yellow ink, tank 12C stores cyan ink, and tank 12M stores magenta ink. Each tank 12K, 12Y, 12C, and 12M supplies ink to head 20. Note that, hereinafter, colors other than black, namely yellow, cyan, and magenta, may be referred to as colors.

[0018] The input device 13 is a button, a touch panel, or the like, and is connected to the control unit 50. The input device 13 is operated by a user, and information such as printing conditions is input from the input device 13 to the control unit 50.

[0019] <head> As shown in Fig. 2, the head 20 has a plurality of nozzles 21, a plurality of ink flow paths 22, and a plurality of drive elements 23 (Fig. 3). The nozzles 21 are open to the bottom surface of the head 20. The plurality of nozzles 21 are aligned at equal intervals in a direction intersecting (for example, perpendicular to) the left-right direction to form a nozzle row. The plurality of nozzle rows (for example, eight nozzles) are aligned at intervals in the left-right direction.

[0020] The ink flow paths 22 include a common flow path 22a and a plurality of individual flow paths 22b branching from the common flow path 22a. The common flow path 22a extends in the front-to-rear direction, and each of the plurality of common flow paths 22a is connected to one of the tanks 12K, 12Y, 12C, and 12M. The individual flow paths 22b are connected to the nozzles 21. Therefore, ink is supplied to the nozzles 21 from each of the tanks 12K, 12Y, 12C, and 12M via the ink flow paths 22.

[0021] Here, two ink flow paths 22 are connected to each of the tanks 12K, 12Y, 12C, and 12M so that the same type of ink is supplied to the nozzles 21 of two adjacent nozzle rows out of the eight nozzle rows. In the two nozzle rows, the nozzles 21 of the right nozzle row and the nozzles 21 of the left nozzle row are arranged alternately in the front-to-rear direction.

[0022] The eight nozzle rows include two black nozzle rows 21K, two yellow nozzle rows 21Y, two cyan nozzle rows 21C, and two magenta nozzle rows 21M, arranged in this order from right to left. Therefore, the two black nozzle rows 21K are located at the right end of the head 20, and the nozzles 21 in the black nozzle row 21K form the first nozzle group 21a. The two magenta nozzle rows 21M are located at the left end of the head 20, and the nozzles 21 in the magenta nozzle row 21M form the second nozzle group 21b. In this embodiment, the two yellow nozzle rows 21Y and the two cyan nozzle rows 21C, which are not located at the ends of the head 20, are not included in either the first nozzle group 21a or the second nozzle group 21b. However, the two yellow nozzle rows 21Y and the two cyan nozzle rows 21C may be included in either the first nozzle group 21a or the second nozzle group 21b. The number of nozzle rows constituting each of the first nozzle group 21a and the second nozzle group 21b is not limited to two, but may be one, or three or more.

[0023] The black nozzles 21k, which are nozzles 21 in the two black nozzle rows 21K, are connected to the black tank 12K and eject black ink. The yellow nozzles 21y, which are nozzles 21 in the two yellow nozzle rows 21Y, are connected to the yellow tank 12Y and eject yellow ink. The cyan nozzles 21c, which are nozzles 21 in the two cyan nozzle rows 21C, are connected to the cyan tank 12C and eject cyan ink. The magenta nozzles 21m, which are nozzles 21 in the two magenta nozzle rows 21M, are connected to the magenta tank 12M and eject magenta ink. Note that hereinafter, the yellow nozzles 21y, cyan nozzles 21c, and magenta nozzles 21m may be referred to as color nozzles.

[0024] The driving element 23 is a piezoelectric element, a heating element, an electrostatic actuator, or the like, and is provided for each nozzle 21, and drives the individual flow path 22b connected to the nozzle 21 to vary the volume of the individual flow path 22b. This applies pressure to the ink in the individual flow path 22b to eject the ink from the nozzle 21.

[0025] <Controller configuration> 3, the control unit 50 includes a network interface (I / F 51), a calculation unit 52, and a storage unit 53. The I / F 51 receives various data such as print data from external devices such as a computer, a camera, a scanner, a network, and a recording medium, and from the input device 13.

[0026] The storage unit 53 is a memory accessible from the calculation unit 52, and includes RAM and ROM. The RAM temporarily stores various data such as print data and data converted by the calculation unit 52. The ROM stores programs for performing various data processing.

[0027] The calculation unit 52 includes a processor such as a CPU, and controls each unit by executing a computer program stored in ROM to perform printing processing, which will be described in detail later.

[0028] Such a control unit 50 is electrically connected to the drive elements 23 via the head drive circuit 24, and controls the drive of the drive elements 23. This controls the ink ejection timing, ejection amount, etc. according to the drive of the drive elements 23, and controls the position and size of dots formed on the printing medium A by the ink from the head 20.

[0029] The control unit 50 is also electrically connected to the transport motor 32 via the transport drive circuit 33 and controls the drive of the transport motor 32. The control unit 50 is electrically connected to the scan motor 43 via the scan drive circuit 44 and controls the drive of the scan motor 43. This controls the rotation speed of the scan motor 43 and the movement speed of the head 20.

[0030] <Printing process> The control unit 50 receives print data from an external device via the I / F 51 and executes a print process based on the print data. The print data includes raster data that defines the image to be printed, and the raster data includes color information for the image. In this print process, the control unit 50 executes a pass in which ink is ejected from the head 20 based on the acquired raster data to form part of an image on the print medium A while moving the carriage 41 on which the head 20 is mounted in one direction, either right or left. After this pass, the control unit 50 moves the print medium A forward, and then executes a pass in which ink is ejected from the head 20 while moving the head 20 in the other direction, either right or left. The control unit 50 then moves the print medium A forward.

[0031] In this way, the control unit 50 alternately changes the movement direction of the head 20 between right and left for each pass, and repeats passes and transport of the printing medium A. As a result, dots are formed on the printing medium A by the ink ejected from the head 20 in each pass, and an image made up of the dots is printed on the printing medium A.

[0032] Furthermore, the control unit 50 determines whether to move the head 20 at a first speed or a second speed faster than the first speed in one pass based on the nozzle information and margin information. Details of the nozzle information, margin information, and determination process are described below.

[0033] <Nozzle information> The nozzle information specifies which nozzle group, the first nozzle group 21a or the second nozzle group 21b, will eject ink when printing an image on a printing medium A by ejecting ink from the nozzles 21 while moving the head 20 left and right.

[0034] Specifically, an external device such as a computer performs image processing such as resolution conversion, color conversion, and halftone processing on data including data on margin settings set by the user on the driver and image data defining the image to be printed, to generate raster data. This converts the image data to a resolution that can be output by the printing device 10. For example, if the colors of the image data are R (red), G (green), and B (blue), they are converted into raster data for each of the four CMYK colors of ink provided by the printing device 10. Therefore, the raster data contains information on the color and type of dots.

[0035] Raster data is binary data consisting of 0 and 1, and represents the type of dot formed by ink ejected from the head 20. Two gradations are blank data (0) that ejects no ink, and dot data (1) that ejects a predetermined amount of ink. Four gradations represent blank data (00) that ejects no ink, small dot data (01) that ejects less than a predetermined amount of ink, medium dot data (10) that ejects a predetermined amount of ink, and large dot data (11) that ejects more than a predetermined amount of ink. This small dot data, medium dot data, and large dot data represent dot data. As a result, raster data that specifies the position and type of dot is formed for each color of the KYCM.

[0036] An external device such as a computer then divides the raster data for each color into passes and sends print data including the raster data to the printing device 10. The control unit 50 receives the print data from the external device via the I / F 51. The control unit 50 then arranges the raster data for each color in accordance with the order in which ink is ejected from the nozzles 21 (the order in which dots are formed). The control unit 50 allocates the raster data to the nozzles 21 that eject ink to form dots and the drive timing of the drive elements 23 corresponding to the nozzles 21, and controls the drive elements 23. As a result, dots and the nozzles 21 that eject the ink of these dots are associated with each other and formed as nozzle information.

[0037] <Margin information> The margin information is information about the margin between the edge of the printing medium A and the image in the scanning direction. Here, the margin information includes first group margin information and second group margin information. The first group margin information is the margin between the edge of the printing medium A and a plurality of first dots that are formed by ink ejected from the first nozzle group 21a among the plurality of dots that make up the image and are closest to the edge of the printing medium A in the scanning direction. Furthermore, the second group margin information is the margin between the edge of the printing medium A and a plurality of second dots that are formed by ink ejected from the second nozzle group 21b among the plurality of dots that make up the image and are closest to the edge of the printing medium A in the scanning direction.

[0038] The margin information includes first-side margin information and second-side margin information. The first-side margin information is the margin between the left edge of the printing medium A in the left-right direction and the image. The second-side margin information is the margin between the right edge of the printing medium A in the left-right direction and the image.

[0039] The margin information includes, for example, black margin information, which is the first group of margin information, and magenta margin information, which is the second group of margin information. The margin information also includes, for example, left margin information, which is the first side margin information, and right margin information, which is the second group of margin information. Thus, the black margin information includes left black margin information, which is the first side margin information, and right black margin information, which is the second side margin information. The magenta margin information includes left magenta margin information, which is the first side margin information, and right magenta margin information, which is the second side margin information.

[0040] Specifically, as described above, the external device generates raster data based on the set margin data and image data. This raster data includes blank data that does not eject ink and dot data that does eject ink. As shown in FIG. 4, based on the raster data, image G is printed in print area B of print medium A in one pass, and image G is not printed in the set margin. This print area B is the area of ​​print medium A other than the set margin, and is the area where image G is formed based on image data. In the case of borderless printing where the set margin value is 0 and there is no set margin, print area B is the entire print medium A. In the case where the set margin dimension is greater than 0 and there is a set margin, print area B is only a portion of print medium A. Print area B is divided into multiple areas per unit area in the front-to-back and left-to-right directions, and dots are formed in each of these areas.

[0041] For example, the dots that make up image G shown in Fig. 4 include at least one of black dots Dk, yellow dots Dy, cyan dots Dc, and magenta dots Dm based on dot data, and may also include blank dots D0 based on blank data. The black dots Dk are first dots and are formed with black ink ejected from the black nozzles 21k. The yellow dots Dy are formed with yellow ink ejected from the yellow nozzles 21y. The cyan dots Dc are formed with cyan ink ejected from the cyan nozzles 21c. The magenta dots Dm are second dots and are formed with magenta ink ejected from the magenta nozzles 21m.

[0042] The left black margin Ekl is the space between the leftmost black dot Dkl in the left-right direction among the multiple black dots Dk and the left edge Al of the printing medium A. The dimension of the left black margin Ekl is the sum of the dimension of the left set margin El between the left edge Al of the printing medium A and the left edge Bl of the printing area B, and the dimension of the left black dot margin Edkl between the left edge Bl of the printing area B and the left edge black dot Dkl.

[0043] The dimensions of this left-side set margin El are the set margin set by the user on the driver. The dimensions of the left-side black dot margin Edkl are obtained based on the presence and position of black dots Dk in the dot data. In the example of Figure 4, the left-most black dots Dkl are placed in the fourth area from the left edge Bl of the print area B. Between the area of ​​this left-most black dot Dkl and the left edge Bl are an area of ​​yellow dots Dy and cyan dots Dc other than the black dots Dk, and one area of ​​blank dots D0. Therefore, these three areas form the left-side black dot margin Edkl, and the dimensions of the three areas in the left-right direction form the dimensions of the left-side black dot margin Edkl.

[0044] The right black margin Ekr is the space between the rightmost black dot Dkr, which is located left-to-right among the multiple black dots Dk, and the right edge Ar of the printing medium A. The dimension of the right black margin Ekr is the sum of the dimension of the right set margin Er between the right edge Ar of the printing medium A and the right edge Br of the printing area B, and the dimension of the right black dot margin Edkr between the right edge Br of the printing area B and the right edge black dot Dkr.

[0045] The dimensions of this right-side set margin Er are the set margins set by the user on the driver. The dimensions of the right-side black dot margin Edkr are obtained based on the presence and position of black dots Dk in the dot data. In the example of Figure 4, the right-side black dots Dkr are placed in the first area from the right edge Br of the print area B. Because there is no area between the area of ​​this right-side black dot Dkr and the right edge Br, the dimensions of the right-side black dot margin Edkr are 0. Therefore, the dimensions of the right-side black margin Ekr are equal to the dimensions of the right-side set margin Er.

[0046] The left magenta margin Eml is the space between the leftmost magenta dot Dml, which is the leftmost of the multiple magenta dots Dm in the horizontal direction, and the left edge Al of the printing medium A. The dimension of the left magenta margin Eml is the sum of the dimension of the left set margin El between the left edge Al of the printing medium A and the left edge Bl of the printing area B, and the dimension of the left magenta dot margin Edml between the left edge Bl of the printing area B and the left edge magenta dot Dml.

[0047] The dimensions of this left-side magenta dot margin Edml are obtained based on the presence and position of magenta dots Dm in the dot data. In the example of Figure 4, the left-side magenta dot Dml is located in the second area from the left edge Bl of the print area B. Between the area of ​​this left-side magenta dot Dml and the left edge Bl is an area of ​​yellow dots Dy other than the magenta dots Dm. Therefore, this one area becomes the left-side magenta dot margin Edml, and the dimensions of this one area in the left-right direction become the dimensions of the left-side magenta dot margin Edml.

[0048] The right magenta margin Emr is the space between the right-most magenta dot Dmr, which is located to the right of the multiple magenta dots Dm in the left-right direction, and the right edge Ar of the printing medium A. The dimension of the right magenta margin Emr is the sum of the dimension of the right set margin Er between the right edge Ar of the printing medium A and the right edge Br of the printing area B, and the dimension of the right magenta dot margin Edmr between the right edge Br of the printing area B and the right edge magenta dot Dmr.

[0049] The dimensions of this right-side magenta dot margin Edmr are obtained based on the presence and position of magenta dots Dm in the dot data. In the example of Figure 4, the right-side magenta dot Dmr is located in the third area from the right edge Br of the print area B. Between the area of ​​this right-side magenta dot Dmr and the right edge Br is an area of ​​black dots Dk other than magenta dots Dm, and an area of ​​blank dots D0. Therefore, these two areas become the right-side magenta dot margin Edmr, and the dimensions of the two areas in the left-right direction become the dimensions of the right-side magenta margin Emr.

[0050] In this way, the margin information is obtained from raster data based on the set margin data and image data, and indicates the set margin based on the set margin data and the dot margin based on the image data. The black margin has a set margin and a dot margin, and this dot margin includes an area of ​​blank dots D0 and an area of ​​color dots Dm, Dc, and Dy of colors other than black dots Dk. The magenta margin has a set margin and a dot margin, and this dot margin includes an area of ​​blank dots D0 and an area of ​​color dots Dc, Dy, and black dots Dk of colors other than magenta dots.

[0051] <Decision process> When executing a printing process based on print data, the control unit 50 determines whether to move the head 20 at a first speed or a second speed, which is faster than the first speed, in one pass based on nozzle information and margin information. The control unit 50 sets the movement start position of the head 20 so that the movement speed of the head 20 becomes the first speed or the second speed from the movement start position of the head 20 to the ink ejection start position or before the ejection start position in one pass. Furthermore, in the immediately preceding pass, the stop position of the head 20 is determined based on the ejection start position and acceleration distance of the current pass. In contrast, the carriage 41 carrying the head 20 moves along the guide rails 42, and therefore the right and left end positions of the left-right movable range of the head 20 are determined according to the guide rails 42. Therefore, even if the head 20 starts moving from either the right or left end position, the movement speed of the head 20 may not reach the second speed at the ink ejection start position or before the ejection start position. In such a case, the control unit 50 performs a determination process to move the head 20 at the first speed, which is slower than the second speed. Details of this determination process will be described below.

[0052] The graphs in FIGS. 5(a) and 5(b) show the relationship between the position and velocity of the head 20 when the head 20 moves at a constant first velocity within the movable range of the head 20. The horizontal axis shows the position of the head 20 in the left-right direction, and the vertical axis shows the moving velocity of the head 20. As shown in FIG. 5(a), when the head 20 moves to the right, it starts moving at the leftmost position, accelerates from velocity 0 to the first velocity within the first left range, moves at a constant velocity of the first velocity within the first constant velocity range, decelerates from the first velocity to velocity 0 within the first right range, and stops at the rightmost position. As shown in FIG. 5(b), when the head 20 moves to the left, it starts moving at the rightmost position, accelerates from velocity 0 to the first velocity within the first right range, moves at a constant velocity of the first velocity within the first constant velocity range, decelerates from the first velocity to velocity 0 within the first left range, and stops at the leftmost position.

[0053] Here, while the head 20 moves at a constant first speed, it ejects ink from the nozzles 21 to form dots on the print medium A and prints an image. In this case, the first nozzle group 21a ejects ink to form dots in the first dot-formable region, and the second nozzle group 21b ejects ink to form dots in the second dot-formable region. This second nozzle group 21b is positioned to the left of the first nozzle group 21a. Therefore, the first dot-formable region and the second dot-formable region are misaligned in the left-right direction.

[0054] For this reason, when the head 20 moves to the right, ejecting ink from the first nozzle group 21a requires a wider margin on the left side than on the right side. On the other hand, when the head 20 moves to the right, ejecting ink from the second nozzle group 21b requires a wider margin on the right side than on the left side. Also, when the head 20 moves to the left, ejecting ink from the first nozzle group 21a requires a wider margin on the right side than on the left side. On the other hand, when the head 20 moves to the left, ejecting ink from the second nozzle group 21b requires a wider margin on the left side than on the right side.

[0055] The graphs in FIGS. 6(a) and 6(b) show the relationship between the position and velocity of the head 20 when the head 20 moves at a constant second velocity within the movable range of the head 20. The horizontal axis shows the position of the head 20 in the left-right direction, and the vertical axis shows the moving velocity of the head 20. As shown in FIG. 6(a), when the head 20 moves to the right, it starts moving at the leftmost position, accelerates from velocity 0 to the second velocity in the second left range, moves at a constant second velocity in the second constant velocity range, decelerates from the second velocity to velocity 0 in the second right range, and stops at the rightmost position. As shown in FIG. 6(b), when the head 20 moves to the left, it starts moving at the rightmost position, accelerates from velocity 0 to the second velocity in the second right range, moves at a constant second velocity in the second constant velocity range, decelerates from the second velocity to velocity 0 in the second left range, and stops at the leftmost position.

[0056] Because the second speed is faster than the first speed, the acceleration distance to the second speed and the deceleration distance from the second speed are longer than the acceleration distance to the first speed and the deceleration distance from the first speed, respectively. Therefore, the second constant speed range is shorter than the first constant speed range. Therefore, the first dot formable region and the second dot formable region when the head 20 moves at the second speed are shorter than the first dot formable region and the second dot formable region when the head 20 moves at the first speed, respectively.

[0057] For example, as shown in the graph in Figure 6(a), a case will be described where the head 20 is moved at the second speed to print in the printing area B. The head 20 starts moving to the right at the left edge position, and when the movement speed of the head 20 reaches the second speed and changes to a constant speed, both the first nozzle group 21a and the second nozzle group 21b are to the left of the left edge Bl of the printing area B and are not inside the printing area B. However, when the head 20 starts to decelerate from the second speed, the first nozzle group 21a is to the right of the right edge Br of the printing area B and is not inside the printing area B, but the second nozzle group 21b is to the left of the right edge Br of the printing area B and is inside the printing area B.

[0058] In such a case, conventional control does not take into account the arrangement of the first nozzle group 21a and the second nozzle group 21b, and therefore printing is performed by moving the head 20 at a first speed. In contrast, the movement speed of the head 20 is determined depending on the positions of the first nozzle group 21a and the second nozzle group 21b. In this case, when printing using only ink from the second nozzle group 21b, the head 20 is moved at the first speed. Furthermore, when printing using ink from both the first nozzle group 21a and the second nozzle group 21b, the head 20 is moved at the first speed. However, when printing using only ink from the first nozzle group 21a, the head 20 is moved at the second speed. This makes it possible to increase printing speed while suppressing degradation in image quality.

[0059] As described above, the movement speed of the head 20 varies depending on the nozzles ejecting ink and the margin. Therefore, the control unit 50 determines the movement speed of the head 20 based on nozzle information and margin information corresponding to the color of the dots. Here, when ink is ejected only from the black nozzles 21k of the first nozzle group 21a, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the black margin information. Furthermore, when ink is not ejected from the black nozzles 21k during printing and ink is ejected only from the color nozzles including the magenta nozzles 21m of the second nozzle group 21b, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the magenta margin information. Here, when the margin value is equal to or greater than the threshold value, the control unit 50 moves the head 20 at the second speed during printing. Furthermore, when the margin value is less than the threshold value, the control unit 50 moves the head 20 at the first speed during printing.

[0060] The control unit 50 starts a process for determining the movement speed of the head 20 by receiving print data from an external device via the I / F 51. In the determination process, as shown in the flowchart in FIG. 7, the control unit 50 first acquires nozzle information based on the color types of raster data included in the acquired print data (step S1). The control unit 50 also acquires margin information, including a set margin and a dot margin, based on the raster data included in the print data (step S2). The control unit 50 then determines, based on the nozzle information, whether or not to eject ink from the color nozzles when printing image G based on the print data (step S3).

[0061] Here, if ink is not to be ejected from the yellow nozzles 21y, cyan nozzles 21c, and magenta nozzles 21m to form the dots of image G, the control unit 50 determines that ink is not to be ejected from the color nozzles (step S3: NO). In this case, the print mode is monochrome printing, in which ink is not ejected from the color nozzles but is ejected from the black nozzles 21k to form the dots of image G, so the control unit 50 executes monochrome printing determination (step S4).

[0062] On the other hand, if ink is ejected from the yellow nozzles 21y, cyan nozzles 21c, and magenta nozzles 21m (step S3: YES), the control unit 50 determines whether or not ink is ejected from the black nozzles 21k when forming dots for image G (step S5). Here, if the printing mode is a color printing mode in which ink is ejected from the magenta nozzles 21m but not from the black nozzles 21k (step S5: NO), the control unit 50 executes a color printing determination (step S6). On the other hand, if the printing mode is a full-color printing mode in which ink is ejected from both the magenta nozzles 21m and the black nozzles 21k when forming dots for image G (step S5: YES), the control unit 50 executes a full-color printing determination (step S7).

[0063] (Monochrome printing judgment) In the monochrome printing determination in step S4, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the right black margin information when moving the head 20 left in the left-right direction during printing and discharging ink from the black nozzles 21k without discharging ink from the magenta nozzles 21m. Also, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the left black margin information when moving the head 20 right in the left-right direction during printing and discharging ink from the black nozzles 21k without discharging ink from the magenta nozzles 21m.

[0064] That is, as shown in the example of monochrome printing determination in FIG. 8, when monochrome printing is performed, the control unit 50 determines the movement direction of the head 20 for each pass (step S10). When the head 20 moves to the right in a pass, the control unit 50 determines whether the left black margin Ekl is equal to or greater than a predetermined threshold (step S11). If the left black margin Ekl is equal to or greater than the threshold (step S11: YES), the control unit 50 determines the movement speed of the head 20 to be a high second speed (step S12). This allows the head 20 to accelerate to the second speed within its movable range and eject black ink while moving at a constant second speed to form left-edge black dots Dkl. This increases the printing speed.

[0065] On the other hand, if the left black margin Ekl is less than the threshold value (step S11: NO), the control unit 50 determines the movement speed of the head 20 to be a slow first speed (step S13). This allows the head 20 to accelerate to the first speed and eject black ink while moving at a constant speed of the first speed to form the left edge black dots Dkl. This prevents degradation of image quality.

[0066] In step S10, if the head 20 moves left in a pass (step S10: NO), the control unit 50 determines whether the right black margin Ekr is equal to or greater than a predetermined threshold (step S14). If the right black margin Ekr is equal to or greater than the threshold (step S14: YES), the control unit 50 determines the movement speed of the head 20 to be a high second speed (step S15). This allows the head 20 to accelerate to the second speed within its movable range and eject black ink while moving at a constant second speed to form right-edge black dots Dkr. This increases the printing speed.

[0067] On the other hand, if the right black margin Ekr is less than the threshold value (step S14: NO), the control unit 50 determines the movement speed of the head 20 to be a slow first speed (step S16). As a result, the head 20 accelerates to the first speed and ejects black ink while moving at a constant speed of the first speed to form the right edge black dots Dkr. This prevents degradation of image quality.

[0068] (Color printing judgment) In the color printing determination in step S6, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the left magenta margin information when moving the head 20 left in the left-right direction during printing and discharging ink from the magenta nozzles 21m without discharging ink from the black nozzles 21k. Also, when moving the head 20 right during printing and discharging ink from the magenta nozzles 21m without discharging ink from the black nozzles 21k, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the right magenta margin information.

[0069] That is, as shown in the example of color printing determination in FIG. 9, when color printing is performed, the control unit 50 determines the movement direction of the head 20 for each pass (step S20). When the head 20 moves to the right in a pass, the control unit 50 determines whether the right magenta margin Emr is equal to or greater than a predetermined threshold (step S21). If the right magenta margin Emr is equal to or greater than the threshold (step S21: YES), the control unit 50 determines the movement speed of the head 20 to be a high-speed second speed (step S22). This allows the head 20 to eject magenta ink during constant speed movement at the second speed to form the right-end magenta dot Dmr, and then decelerate from the second speed within the movable range and stop. This allows for faster printing.

[0070] On the other hand, if the right magenta margin Emr is less than the threshold value (step S21: NO), the control unit 50 determines the movement speed of the head 20 to be a slow first speed (step S23). As a result, the head 20 ejects magenta ink while moving at the constant first speed to form the right edge magenta dot Dmr, and then decelerates from the first speed and stops. This prevents degradation of image quality.

[0071] In step S20, if the head 20 moves left in a pass (step S20: NO), the control unit 50 determines whether the left magenta margin Eml is equal to or greater than a predetermined threshold (step S24). If the left magenta margin Eml is equal to or greater than the threshold (step S24: YES), the control unit 50 determines the movement speed of the head 20 to be a high-speed second speed (step S25). This allows the head 20 to eject magenta ink during constant movement at the second speed to form the left-edge magenta dot Dml, and then decelerate from the second speed within the movable range and stop. This allows for faster printing.

[0072] On the other hand, if the right magenta margin Emr is less than the threshold value (step S24: NO), the control unit 50 determines the movement speed of the head 20 to be a slow first speed (step S26). As a result, the head 20 ejects magenta ink while moving at the constant first speed to form the left edge magenta dot Dml, and then decelerates from the first speed and stops. This prevents degradation of image quality.

[0073] (Full color printing judgment) In the full-color printing determination in step S7, when ink is ejected from the black nozzles 21k and the magenta nozzles 21m while moving the head 20 to the left during printing, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the right black margin information and the left magenta margin information. Also, when ink is ejected from the black nozzles 21k and the magenta nozzles 21m while moving the head 20 to the right during printing, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the left black margin information and the right magenta margin information.

[0074] 10, when full-color printing is performed, the control unit 50 determines the movement direction of the head 20 for each pass (step S30). When the head 20 moves to the right in a pass, the control unit 50 determines whether the left black margin Ekl is equal to or greater than a predetermined threshold (step S31). If the left black margin Ekl is equal to or greater than the threshold (step S31: YES), the control unit 50 determines whether the right magenta margin Emr is equal to or greater than a predetermined threshold (step S32).

[0075] If the right magenta margin Emr is equal to or greater than the threshold (step S32: YES), the control unit 50 determines the movement speed of the head 20 to be the second speed (step S33). This allows the head 20 to accelerate to the second speed within its movable range, and then eject black ink while moving at a constant speed at the second speed to form the left-edge black dot Dkl. Then, the head 20 ejects magenta ink while moving at a constant speed at the second speed to form the right-edge magenta dot Dmr, and then decelerates from the second speed within its movable range and stops. This allows for faster printing.

[0076] On the other hand, if the left black margin Ekl is less than the threshold value (step S31: NO) and if the right magenta margin Emr is less than the threshold value (step S32: NO), the control unit 50 determines the movement speed of the head 20 to be a slow first speed (step S34). As a result, the head 20 accelerates to the first speed, and while moving at a constant speed at the first speed, ejects black ink from the head 20 to form the left edge black dot Dkl. Then, while moving at a constant speed at the first speed, the head 20 ejects magenta ink to form the right edge magenta dot Dmr, and then decelerates from the first speed and stops. This suppresses degradation of image quality.

[0077] In step S30, if the head 20 moves left in a pass (step S30: NO), the control unit 50 determines whether the right black margin Ekr is equal to or greater than a predetermined threshold (step S35). If the right black margin Ekr is equal to or greater than the threshold (step S35: YES), the control unit 50 determines whether the left magenta margin Eml is equal to or greater than a predetermined threshold (step S36). If the left magenta margin Eml is equal to or greater than the threshold (step S36: YES), the control unit 50 determines the movement speed of the head 20 to be a high second speed (step S37). This allows the head 20 to accelerate to the second speed within the movable range and eject black ink while moving at a constant second speed to form the right edge black dot Dkr. Then, the head 20 ejects magenta ink while moving at a constant second speed to form the left edge magenta dot Dml, and then decelerates from the second speed within the movable range and stops. This increases the printing speed.

[0078] On the other hand, if the right black margin Ekr is less than the threshold value (step S35: NO) and if the right magenta margin Emr is less than the threshold value (step S36: NO), the control unit 50 determines the movement speed of the head 20 to be a slow first speed (step S38). As a result, the head 20 accelerates to the first speed and ejects black ink while moving at a constant speed at the first speed to form the right edge black dot Dkr. Then, the head 20 ejects magenta ink while moving at a constant speed at the first speed to form the left edge magenta dot Dml, and then decelerates from the first speed and stops. This prevents degradation of image quality.

[0079] <Actions and Effects> In this embodiment, control is performed to print an image on print medium A by ejecting ink from a nozzle group based on the nozzle information while moving head 20 in the scanning direction at a first speed or a second speed faster than the first speed based on nozzle information and margin information. This makes it possible to select the movement speed of head 20 based on the positions of nozzles 21 in head 20, so there are more cases where the second speed is selected than in the past. This makes it possible to speed up printing while suppressing degradation of image quality.

[0080] In this embodiment, the first nozzle group 21a has a black nozzle row 21K that ejects black ink, and the second nozzle group 21b has a magenta nozzle row 21M. In the case of black printing, determination is made using the first nozzle group 21a, in the case of color printing, determination is made using the second nozzle group 21b, and in the case of black color printing, determination is made using both the first nozzle group 21a and the second nozzle group 21b. This allows the corresponding nozzle group to be selected depending on the print mode, thereby speeding up the processing of the control unit 50.

[0081] In this embodiment, the margin information includes a set margin preset by the user and blank dots, which are non-ejected dots in the print area B other than the set margin. More specifically, the margin information includes first group margin information, which is the margin between the edge of the print medium A and a plurality of first dots formed by ink ejected from the first nozzle group 21a among the plurality of dots constituting the image and closest to the edge of the print medium A in the scanning direction, and second group margin information, which is the margin between the edge of the print medium A and a plurality of second dots formed by ink ejected from the second nozzle group 21b among the plurality of dots constituting the image and closest to the edge of the print medium A in the scanning direction. This enables more accurate speed selection of the head 20 based on the positions of the dots ejected from the nozzle groups, resulting in more cases where the second speed is selected than in the past. This allows for faster printing while suppressing degradation of image quality.

[0082] In this embodiment, when ink is ejected from the first nozzle group 21a without ejecting ink from the second nozzle group 21b during printing, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the first group margin information. When ink is ejected from the second nozzle group 21b without ejecting ink from the first nozzle group 21a during printing, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the second group margin information. This allows margin information to be selected according to the print mode, thereby speeding up the processing of the control unit 50.

[0083] In this embodiment, the margin information includes first-side margin information, which is the margin between the image and the edge of the print medium A in the first direction in the scanning direction, and second-side margin information, which is the margin between the image and the edge of the print medium A in the second direction in the scanning direction. This allows margin information to be selected according to the movement direction of the head 20, thereby speeding up processing by the control unit 50.

[0084] In this embodiment, when the control unit 50 moves the head 20 in a first direction, which is the scanning direction, during printing, and ejects ink from the first nozzle group 21a without ejecting ink from the second nozzle group 21b, the control unit 50 determines whether to move the head 20 at a first speed or a second speed based on the second-side margin information of the first group margin information. When the control unit 50 moves the head 20 in a second direction, which is the scanning direction, during printing, and ejects ink from the first nozzle group 21a without ejecting ink from the second nozzle group 21b, the control unit 50 determines whether to move the head 20 at a first speed or a second speed based on the first-side margin information of the first group margin information. This allows the control unit 50 to select only the margin information necessary according to the print mode and the movement direction of the head 20 and determine the movement speed of the head 20, thereby speeding up the processing of the control unit 50.

[0085] In this embodiment, when the control unit 50 moves the head 20 in a first direction, which is the scanning direction, during printing, and ejects ink from the second nozzle group 21b without ejecting ink from the first nozzle group 21a, the control unit 50 determines whether to move the head 20 at a first speed or a second speed based on the first-side margin information of the second group margin information. When the control unit 50 moves the head 20 in a second direction, which is the scanning direction, during printing, and ejects ink from the second nozzle group 21b without ejecting ink from the first nozzle group 21a, the control unit 50 determines whether to move the head 20 at a first speed or a second speed based on the second-side margin information of the second group margin information. This allows the control unit 50 to select only the margin information necessary according to the print mode and the movement direction of the head 20 and determine the movement speed of the head 20, thereby speeding up the processing of the control unit 50.

[0086] In this embodiment, when ejecting ink from the first nozzle group 21 a and the second nozzle group 21 b while moving the head 20 in a first direction, which is the scanning direction, during printing, the control unit 50 determines whether to move the head 20 at a first speed or a second speed based on the second-side margin information of the first group margin information and the first-side margin information of the second group margin information. When ejecting ink from the first nozzle group 21 a and the second nozzle group 21 b while moving the head 20 in a second direction, which is the scanning direction, during printing, the control unit 50 determines whether to move the head 20 at a first speed or a second speed based on the first-side margin information of the first group margin information and the second-side margin information of the second group margin information. This allows the control unit 50 to select margin information according to the print mode and the movement direction of the head 20, thereby speeding up processing by the control unit 50.

[0087] In this embodiment, when the margin value is equal to or greater than the threshold value, the control unit 50 moves the head 20 at the second speed during printing. When the margin value is less than the threshold value, the control unit 50 moves the head 20 at the first speed during printing. This allows the speed of the head 20 to be selected based on the threshold value, thereby speeding up the processing of the control unit 50.

[0088] <Variation 1> In the printing device 10 according to the first modification, in the above embodiment, when there is a margin, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the nozzle information and the margin information. When there is no margin, the control unit 50 moves the head 20 at the first speed during printing.

[0089] Specifically, as shown in an example of the determination process in Fig. 11, the control unit 50 executes the processes of steps S8 and S9 between steps S2 and S3 in the flowchart of Fig. 7. In the process of step S8, the control unit 50 determines whether there is any margin based on the margin information.

[0090] Here, for example, in the case of borderless printing, when the print area B is the entire area of ​​the print medium A, the margin between the edge of the print medium A and the image in the left-right direction is zero, i.e., there is no margin (step S8: YES). In this case, the control unit 50 determines the movement speed of the head 20 to be a slow first speed (step S9).

[0091] On the other hand, if the margin between the image and the edge of print medium A in the left-right direction is set to be greater than 0, the control unit 50 determines that there is a margin (step S8: NO), and therefore executes the processes from step S3 onwards. As a result, in the monochrome printing determination in step S4, the color printing determination in step S6, and the full-color printing determination in step S7, if each margin is equal to or greater than a threshold, the control unit 50 determines the movement speed of head 20 to be the second speed, and if each margin is less than the threshold, the control unit 50 determines the movement speed of head 20 to be the first speed. This allows the printing device 10 to increase printing speed while suppressing degradation of image quality.

[0092] <Variation 2> In the printing device 10 according to the second modification, in the above-described embodiment and the first modification, the thresholds include a first threshold when ink is ejected from the black nozzles 21k during printing, and a second threshold different from the first threshold when ink is ejected from the magenta nozzles 21m during printing. The thresholds also include a third threshold when the head 20 moves to the left during printing, and a fourth threshold when the head 20 moves to the right during printing.

[0093] As described above, in the head 20, the first nozzle group 21a and the second nozzle group 21b, which is disposed to the left of the first nozzle group 21a, are arranged so as to be offset from each other in the movement direction of the head 20. Therefore, the range in which the first dots can be formed by the first nozzle group 21a and the range in which the second dots can be formed by the second nozzle group 21b are offset from each other in the left-right direction. Therefore, the first threshold when ink is ejected from the black nozzles 21k and the second threshold when ink is ejected from the magenta nozzles 21m are different from each other.

[0094] Also, the acceleration distance and deceleration distance of the head 20 may differ from each other. Furthermore, the movable area of ​​the carriage 62 relative to the printing medium A may differ between when the carriage 62 moves to the left and when the carriage 62 moves to the right. In such cases, the third threshold when the head 20 moves to the left and the fourth threshold when the head 20 moves to the right are different from each other.

[0095] <Variation 3> In the printing device 10 according to Modification 3, in the above-described embodiment and Modifications 1 and 2, the control unit 50 acquires size information regarding the size of the printing medium A. If the size is a predetermined size, the control unit 50 determines whether to move the head 20 at the first speed or the second speed based on the nozzle information and margin information. If the size is not a predetermined size, the control unit 50 determines to move the head 20 at the second speed.

[0096] Specifically, as shown in an example of the determination process in Fig. 12, steps S8' and S9' are executed between steps S2 and S3 in the flowchart of Fig. 7. In step S8', the control unit 50 determines whether the print medium A is of a predetermined size.

[0097] Here, the predetermined size is, for example, A4 size, which is the maximum size that the printing device 10 can print, and is a size that may not have enough margin to allow the head 20 to move at the second speed. The size of the print medium A may be included in the print data, may be input to the control unit 50 by the user via the input device 13, or may be obtained by the control unit 50 from a detection signal of a sensor that detects the print medium A. Furthermore, the size is not limited to the maximum size that the printing device 10 can print, and multiple sizes may be set.

[0098] If the print medium A is smaller than A4 size, the control unit 50 determines that the size of the print medium A is not the predetermined size (step S8': NO) and determines the movement speed of the head 20 to be the second speed, which is a higher speed (step S9'). On the other hand, if the print medium A is A4 size, the control unit 50 determines that the size of the print medium A is the predetermined size (step S8': YES), and the control unit 50 executes the processes from step S3 onwards. As such, with a large-sized print medium A, the print area B on the print medium A is larger than the movable range of the head 20 in the left-right direction, and it may not be possible to print in the print area B while moving the head 20 at the second speed. Therefore, in the monochrome printing determination in step S4, the color printing determination in step S6, and the full-color printing determination in step S7, if each margin is equal to or greater than a threshold value, the control unit 50 determines the movement speed of the head 20 to be the second speed. If each margin is less than a threshold value, the control unit 50 determines the movement speed of the head 20 to be the first speed.

[0099] The control unit 50 may determine the movement speed of the head 20 based on the orientation of the print medium A in addition to the size of the print medium A. The print medium A may have a rectangular shape with one side longer than the other. In this case, even if the print medium A is smaller than a predetermined size, such as A5 size (not the maximum A4 size that the printing device 10 can print), depending on the orientation of the print medium A, the length of the print medium A in the left-right direction, which is the direction of movement of the head 20 by the carriage 41, may be the same as that of the A4 size. In such a case, the print area B may be larger than the range of movement of the head 20 in the left-right direction, and there may not be enough space to move the head 20 at the second speed. For this reason, the control unit 50 may determine the movement speed of the head 20 based on the orientation of the print medium A in addition to the size of the print medium A. The orientation of the print medium A may be input to the control unit 50 by the user via the input device 13, or may be obtained by the control unit 50 from a detection signal from a sensor that detects the print medium A.

[0100] <Other embodiments> In all of the above embodiments and modifications, the plurality of nozzles 21 in the black nozzle row 21K are defined as the first nozzle group 21a. The plurality of nozzles 21 in the magenta nozzle row 21M are defined as the second nozzle group 21b. However, the first nozzle group 21a and the second nozzle group 21b are not limited to the above configuration. The plurality of nozzles 21 in the black nozzle row 21K and the yellow nozzle row 21Y located to the right of the center of the head 20 in the left-right direction may be defined as the first nozzle group 21a, and the plurality of nozzles 21 in the cyan nozzle row 21C and the magenta nozzle row 21M located to the left of the center of the head 20 in the left-right direction may be defined as the second nozzle group 21b. The plurality of nozzles 21 in the black nozzle row 21K may be defined as the first nozzle group 21a, and the plurality of nozzles 21 in the yellow nozzle row 21Y, the cyan nozzle row 21C, and the magenta nozzle row 21M may be defined as the second nozzle group 21b. The control unit 50 may determine the movement speed of the head 20 based on the margins for each of multiple or all of the color inks that the printing device 10 is equipped with.

[0101] In all of the above embodiments and modifications, the control unit 50 determines the movement speed of the head 20 for each pass. However, the control unit 50 may also determine the movement speed of the head 20 for the entire printing based on the print data. In this case, before printing begins, the control unit 50 determines the movement speed of the head 20 for at least the pass with the smallest margin among the multiple passes included in the printing. Then, if the multiple determinations include a determination that the movement speed of the head 20 is the first speed, the control unit 50 moves the head 20 at the first speed for all passes in the printing. This shortens the time required for the determination process by the control unit 50 while improving the uniformity of the printed image quality between passes.

[0102] Alternatively, when printing multiple pages of print medium A based on a single print data, the control unit 50 may determine the movement speed of the head 20 for each page. In this case, the control unit 50 determines the movement speed of the head 20 for each of the multiple passes included in the printing before printing begins. Then, when the multiple determinations for each page include a determination that the movement speed of the head 20 is the first speed, the control unit 50 moves the head 20 at the first speed for all passes in printing that page. This improves the uniformity of the printed image quality between passes.

[0103] In all of the above embodiments and variations, an external device such as a computer performs image processing on the set margin data and image data to generate raster data and transmits print data including the raster data to the printing device 10. The control unit 50 of the printing device 10 acquires print data from the external device via the I / F 51. However, the method of acquiring raster data is not limited to this. For example, the control unit 50 may acquire image data from an external device such as a scanner via the I / F 51, acquire set margin data from the input device 13, etc., perform image processing on the set margin data and image data, and generate raster data. In this way, the process of combining the set margin data with image data to generate raster data may be performed by an external device or by the control unit 50 of the printing device 10.

[0104] In addition, in all of the above embodiments and modifications, the margin information is information about the set margin based on the set margin data and the dot margin based on the image data, and the movement speed of the head 20 is determined based on the set margin and the dot margin. However, the movement speed of the head 20 may be determined based on the set margin rather than the dot margin. In this case, the margin information includes information about the set margin but not the dot margin. In this case, the external device may send print data including raster data and set margin data to the printing device 10. The control unit 50 of the printing device 10 acquires the set margin data as margin information without processing the raster data, thereby speeding up data processing and improving printing speed. Note that the control unit 50 may also acquire the set margin from the raster data as margin information. Alternatively, the control unit 50 may acquire the dot margin from the raster data as margin information rather than the set margin as margin information.

[0105] Furthermore, the set margins do not have to be set by the user. For example, a driver in an external device such as a computer may set the non-image area on print medium A based on the set margins and raster data, regardless of the user's intention. Also, the control unit 50 of the printing device 10 may set the non-image area on print medium A based on the set margins and raster data, regardless of the user's intention.

[0106] Furthermore, in all of the above embodiments and modifications, the control unit 50 obtains nozzle information based on the color type of the raster data included in the print data, but this is not limited to this. For example, an external device may determine which color ink will be ejected from print setting information, and include color information separate from the raster data in the print data and send it to the printing device 10. This allows the control unit 50 to obtain nozzle information from the color information without processing the raster data, thereby shortening data processing time and speeding up printing.

[0107] It should be noted that all of the above embodiments may be combined with one another as long as they do not exclude one another. Furthermore, many improvements and other embodiments of the present invention will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present invention. Details of the structure and / or function of the present invention may be substantially changed without departing from the spirit of the present invention. [Industrial Applicability]

[0108] The present invention can be applied to a printing apparatus that can increase printing speed while suppressing degradation of image quality. [Explanation of symbols]

[0109] 0 :Speed 10:Printing device 20: Head 21: Nozzle 40: Scanning device 50: Control unit

Claims

1. a head having a plurality of nozzles that eject ink onto a printing medium; a scanning device that moves the head in a first scanning direction and a second scanning direction opposite to the first scanning direction; a control unit, the plurality of nozzles includes a first nozzle group which is a plurality of the nozzles arranged in an intersecting direction intersecting the scanning direction, and a second nozzle group which is a plurality of the nozzles arranged in the intersecting direction and which are disposed further in the first direction of the scanning direction than the first nozzle group, The control unit acquiring nozzle information that specifies whether the ink is to be ejected from the first nozzle group or the second nozzle group when printing an image on the print medium by ejecting the ink from the nozzles while moving the head in the scanning direction; obtaining margin information relating to a margin between an edge of the printing medium in the scanning direction and the image; Based on the nozzle information and the margin information, a speed at which the head is moved is determined to be a first speed in a first case in which the margin value is less than a predetermined threshold value, or a speed at which the head is moved is determined to be a second speed faster than the first speed in a second case in which the margin value is equal to or greater than the threshold value and the margin is wider than in the first case, a printing device that prints the image on the printing medium by ejecting the ink from the nozzle group based on the nozzle information while moving the head in the scanning direction at the determined speed;

2. the first nozzle group has a plurality of nozzles that eject the black ink, The printing apparatus according to claim 1 , wherein the second nozzle group has a plurality of nozzles that eject the ink of each color.

3. The margin information is first group margin information, which is the margin between an edge of the printing medium and a plurality of first dots formed by the ink ejected from the first nozzle group among the plurality of dots constituting the image and which are closest to the edge of the printing medium in the scanning direction; 3. The printing device according to claim 1, further comprising second group margin information, which is the margin between the edge of the printing medium and a plurality of second dots formed by the ink ejected from the second nozzle group among the plurality of dots constituting the image and which are closest to the edge of the printing medium in the scanning direction.

4. The control unit when the ink is ejected from the first nozzle group without ejecting the ink from the second nozzle group during the printing, determining whether to move the head at the first speed or the second speed based on the first group margin information; 4. The printing device according to claim 3, wherein when the ink is not ejected from the first nozzle group but is ejected from the second nozzle group during printing, it is determined whether to move the head at the first speed or the second speed based on the second group margin information.

5. The margin information is First side margin information that is the margin between the edge of the printing medium in the first direction in the scanning direction and the image; 5. The printing device according to claim 3, further comprising second side margin information that is the margin between the image and an edge of the printing medium in the second direction in the scanning direction.

6. The control unit when ejecting the ink from the first nozzle group without ejecting the ink from the second nozzle group while moving the head in the first direction of the scanning direction during printing, determining whether to move the head at the first speed or the second speed based on the second side margin information of the first group margin information; 6. The printing device according to claim 5, wherein, when the ink is ejected from the first nozzle group without ejecting the ink from the second nozzle group while moving the head in the second direction of the scanning direction during printing, it is determined whether to move the head at the first speed or the second speed based on the first side margin information of the first group margin information.

7. The control unit when the ink is ejected from the second nozzle group without ejecting the ink from the first nozzle group while moving the head in the first direction of the scanning direction during printing, determining whether to move the head at the first speed or the second speed based on the first side margin information of the second group margin information; 7. The printing device according to claim 5, wherein when the ink is ejected from the second nozzle group without ejecting the ink from the first nozzle group while moving the head in the second direction of the scanning direction during printing, it is determined whether to move the head at the first speed or the second speed based on the second side margin information of the second group margin information.

8. The control unit when ejecting the ink from the first nozzle group and the second nozzle group while moving the head in the first direction of the scanning direction during printing, determining whether to move the head at the first speed or the second speed based on the second side margin information of the first group margin information and the first side margin information of the second group margin information; 8. A printing device according to claim 5, wherein when the ink is ejected from the first nozzle group and the second nozzle group while the head is moved in the second direction of the scanning direction during printing, it is determined whether to move the head at the first speed or the second speed based on the first side margin information of the first group margin information and the second side margin information of the second group margin information.

9. The control unit If there is a margin, determining whether to move the head at the first speed or the second speed based on the nozzle information and the margin information; The printing device according to claim 3 , wherein when there is no margin, the head is moved at the first speed during printing.

10. The control unit If the margin value is equal to or greater than a threshold value, the head is moved at the second speed during printing; The printing device according to claim 3 , wherein when the margin value is less than the threshold value, the head is moved at the first speed during printing.

11. The threshold value is a first threshold value when the ink is ejected from the first nozzle group during printing; The printing device according to claim 10 , further comprising a second threshold value, different from the first threshold value, used when the ink is ejected from the second nozzle group during printing.

12. The threshold value is a third threshold value when the head moves in the first direction of the scanning direction during printing; The printing device according to claim 10 or 11, further comprising: a fourth threshold value when the head moves in the second scanning direction during printing.

13. The control unit Acquire size information of the size of the printing medium; If the size is a predetermined size, determining whether to move the head at the first speed or the second speed based on the nozzle information and the margin information; The printing device according to claim 1 , wherein if the size is not the predetermined size, it is determined to move the head at the second speed.

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