Printing apparatus and printing method
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SEIKO EPSON CORP
- Filing Date
- 2021-12-24
- Publication Date
- 2026-07-30
- Estimated Expiration
- Not applicable · inactive patent
Smart Images
Figure 0007897545000001 
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Abstract
Description
Technical Field
[0001] The present invention relates to a printing apparatus and a printing method.
Background Art
[0002] In the head of an inkjet printer, a configuration in which a plurality of nozzle rows are partially overlapped for printing is known. Also, a single-pass type print head in which a plurality of head modules are alternately shifted in the paper feed direction and arranged side by side in the direction perpendicular to the paper feed is disclosed (see Patent Document 1). In this single-pass type print head, the joint portion between the head modules is arranged such that both head modules overlap, and the nozzles of both head modules are substantially alternately arranged along the direction perpendicular to the paper feed.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] <00者0025>In a configuration in which nozzle rows or head modules are partially overlapped for printing as in Document 1, positional deviation of nozzles at the overlap portion in the arrangement direction of the nozzles causes density unevenness in the printing result. Therefore, it has been necessary to connect component parts with high precision so that positional deviation does not occur. However, the work of precisely connecting component parts for each product individual is laborious and a factor in cost increase.
[0005] Furthermore, even if the components are precisely connected, differences in ink dot placement on the medium and the number of nozzles used to print a single raster line can easily occur in the print result because the timing of ink dot placement differs between overlapping areas and non-overlapping areas where the nozzle rows do not overlap, and the number of nozzles used to print a single raster line also differs. To suppress such density differences, image processing such as density correction is sometimes performed on the print data corresponding to the overlapping areas.
[0006] However, as long as overlapping and non-overlapping areas coexist, it is not easy to eliminate the density differences in the printed result caused by their fundamental differences. Therefore, improvements are needed to eliminate the degradation of image quality caused by overlapping areas. [Means for solving the problem]
[0007] The printing apparatus comprises a print head having a first nozzle row in which a plurality of nozzles are arranged in the nozzle alignment direction, and a second nozzle row in which a plurality of nozzles are arranged offset from the first nozzle row in the nozzle alignment direction, and a control unit that controls the ejection of ink from the nozzles of the print head to the medium based on print data, wherein the control unit sets a complementary image as a part of the image to be printed on the medium, corresponding to the boundary between the first nozzle row and the second nozzle row, and prints the print data for printing the complementary image to the first adjacent nozzles of the first nozzle row adjacent to the boundary and the nozzles of the second nozzle row adjacent to the boundary The print data is assigned to at least one of the adjacent second adjacent nozzles, and the image to be completed is completed by ejecting ink from at least one of the first adjacent nozzle and the second adjacent nozzle based on the assigned print data. When the nozzle pitch is defined as the distance between the nozzles in the first nozzle row or the distance between the nozzles in the second nozzle row in the nozzle row direction, the boundary portion is positioned between the first adjacent nozzle and the second adjacent nozzle, such that the first adjacent nozzle, which is the nozzle at the end of the first nozzle row on the second nozzle row side of the first nozzle row, and the second adjacent nozzle, which is the nozzle at the end of the second nozzle row on the first nozzle row side of the second nozzle row, are spaced at a distance greater than the nozzle pitch. The printing apparatus comprises a print head having a first nozzle row in which a plurality of nozzles are arranged in the nozzle alignment direction, and a second nozzle row in which a plurality of nozzles are arranged offset from the first nozzle row in the nozzle alignment direction, and a control unit that controls the ejection of ink from the nozzles of the print head to the medium based on print data, wherein the control unit sets a target image to be completed as a part of the image to be printed on the medium, corresponding to the boundary between the first nozzle row and the second nozzle row, and assigns print data for printing the target image to at least one of the first adjacent nozzles of the first nozzle row adjacent to the boundary and the second adjacent nozzles of the second nozzle row adjacent to the boundary, and controls the ejection of ink from the nozzles of the print head to the medium based on the assigned print data The image to be complemented is complemented by ink ejection from at least one of the first adjacent nozzle and the second adjacent nozzle, the end of the first nozzle row on the second nozzle row side and the end of the second nozzle row on the first nozzle row side overlap in the nozzle row direction, and when the distance between the nozzles of the first nozzle row or the distance between the nozzles of the second nozzle row in the nozzle row direction is defined as the nozzle pitch, the first adjacent nozzle and the second adjacent nozzle are separated by a distance longer than the nozzle pitch, and the boundary portion is positioned between the first adjacent nozzle and the second adjacent nozzle by making the nozzles of the first nozzle row and the second nozzle row located between the first adjacent nozzle and the second adjacent nozzle unused nozzles that are not used for ink ejection. 。
[0008] The printing apparatus includes a print head having a nozzle row in which a plurality of nozzles are arranged in the nozzle row direction and movable along a main scanning direction intersecting the nozzle row direction, and a control unit that causes the print head to execute a pass in which ink is ejected from the nozzles to the medium based on print data as the movement occurs, wherein the control unit sets a target image to be completed as a part of the image to be printed on the medium, corresponding to the boundary between the position of the nozzle row on the medium when the first pass is executed and the position of the nozzle row on the medium when the second pass following the first pass is executed, assigns print data for printing the target image to at least one of the first adjacent nozzles in the nozzle row when the first pass is executed and adjacent to the boundary, and a second adjacent nozzle in the nozzle row when the second pass is executed and adjacent to the boundary, and completes the target image by ejecting ink from at least one of the first adjacent nozzles and the second adjacent nozzle based on the assigned print data.
[0010] A printing method that prints by ejecting ink from nozzles onto a medium based on print data while moving a print head having a nozzle row in which multiple nozzles are arranged in the nozzle row direction along a main scanning direction that intersects the nozzle row direction, includes a setting step of setting a target image to be completed as a part of the image to be printed on the medium, corresponding to the boundary between the position of the nozzle row on the medium during the execution of the first pass and the position of the nozzle row on the medium during the execution of the second pass following the first pass; an assignment step of assigning print data for printing the target image to at least one of the first adjacent nozzles, which are nozzles in the nozzle row during the execution of the first pass and adjacent to the boundary, and the second adjacent nozzles, which are nozzles in the nozzle row during the execution of the second pass and adjacent to the boundary; and a completion step of completing the target image by ejecting ink from at least one of the first adjacent nozzles and the second adjacent nozzles based on the assigned print data. [Brief explanation of the drawing]
[0011] [Figure 1] A block diagram showing a simplified configuration of the apparatus in this embodiment. [Figure 2] A diagram illustrating the relationship between the medium and the print head of the first embodiment in a simplified manner from an overhead view. [Figure 3] A diagram illustrating the relationship between the medium and the print head of the second embodiment in a simplified manner from an overhead view. [Figure 4] A flowchart illustrating the print control process. [Figure 5] A diagram illustrating print data that includes virtual raster lines. [Figure 6] A diagram illustrating a specific example of the complementary process. [Figure 7] Figures 7A, 7B, 7C, and 7D illustrate the positions of the boundary portions in the print head of the second embodiment. [Figure 8] A diagram illustrating a print head according to the third embodiment. [Figure 9] A diagram illustrating the relationship between the medium and the print head of the fourth embodiment in a simplified manner from an overhead view. [Modes for carrying out the invention]
[0012] Embodiments of the present invention will be described below with reference to the figures. Note that the figures are merely illustrative examples for illustrating these embodiments. Because the figures are illustrative, their proportions and shapes may not be accurate, they may not be consistent with each other, or some parts may be omitted.
[0013] 1. Outline of the device configuration: Figure 1 shows a simplified configuration of the printing apparatus 10 according to this embodiment. The printing method of this embodiment is performed by the printing apparatus 10. The printing device 10 includes a control unit 11, a display unit 13, an operation reception unit 14, a storage unit 15, a communication IF 16, a transport unit 17, a print head 18, etc. IF stands for interface. The control unit 11 is composed of one or more ICs having a CPU 11a as a processor, ROM 11b, RAM 11c, etc., and other non-volatile memory, etc.
[0014] In the control unit 11, the processor, that is, the CPU 11a, executes arithmetic processing according to the program 12 stored in the ROM 11b and other memories, etc., using the RAM 11c, etc. as a work area, thereby realizing various functions such as the print data generation unit 12a and the print control unit 12b. The processor is not limited to a single CPU, and may be configured to perform processing by a plurality of CPUs or hardware circuits such as ASICs, or may be configured such that the CPU and the hardware circuit cooperate to perform processing.
[0015] The display unit 13 is a means for displaying visual information, and is constituted by, for example, a liquid crystal display, an organic EL display, or the like. The display unit 13 may be configured to include a display and a drive circuit for driving the display. The operation reception unit 14 is a means for receiving an input by the user, and is realized by, for example, a physical button, a touch panel, a mouse, a keyboard, or the like. Of course, the touch panel may be realized as a function of the display unit 13. The display unit 13 and the operation reception unit 14 may be referred to as an operation panel of the printing apparatus 10. The display unit 13 and the operation reception unit 14 may be a part of the configuration of the printing apparatus 10, or may be a peripheral device externally attached to the printing apparatus 10.
[0016] The storage unit 15 is, for example, a storage means by a hard disk drive, a solid state drive, or other memories. A part of the memory possessed by the control unit 11 may be regarded as the storage unit 15. The storage unit 15 may be regarded as a part of the control unit 11. The communication IF 16 is a general term for one or more IFs for the printing apparatus 10 to communicate with an external device by wire or wirelessly in accordance with a predetermined communication protocol including a known communication standard. The external device is, for example, a communication device such as a personal computer, a server, a smartphone, a tablet terminal, or the like.
[0017] The conveying unit 17 is a means for conveying the medium 30 along a predetermined conveying direction under the control of the control unit 11. The conveying unit 17 includes, for example, rollers that rotate to convey the medium 30, a motor as a power source for rotation, and the like. Further, the conveying unit 17 may be a mechanism that mounts the medium 30 on a belt or a pallet that moves by a motor and conveys the medium 30. The medium 30 is, for example, paper, but may be any medium that can be a printing target, and may be a material other than paper such as a film or a fabric.
[0018] The printing head 18 is a means for performing printing on the medium 30 conveyed by the conveying unit 17 by ejecting a liquid such as ink from a plurality of nozzles by an inkjet method under the control of the control unit 11. The droplets ejected from the nozzles of the printing head 18 are called dots. The printing head 18 can eject inks of a plurality of colors such as cyan (C), magenta (M), yellow (Y), and black (K), for example. Of course, the printing head 18 is not limited to CMYK inks and can eject inks and liquids of various colors. The printing head 18 may be referred to as a liquid ejection head, a recording head, a printing head, an inkjet head, or the like.
[0019] The printing apparatus 10 may be configured by a single printer, or may be realized by a system having a plurality of communicably connected devices. For example, the printing apparatus 10 may be a system including an information processing apparatus that plays the role of the control unit 11 and a printer that includes the conveying unit 17 and the printing head 18 and executes printing under the control of the information processing apparatus. In this case, the information processing apparatus can be regarded as a printing control apparatus, an image processing apparatus, or the like.
[0020] 2. Configuration of the printing head: FIG. 2 simply shows the relationship between the medium 30 and the printing head 18 from a top view. The printing head 18 shown in FIG. 2 is referred to as the printing head 18 of the "first embodiment". The arrow labeled D1 indicates the transport direction D1 of the medium 30 by the transport unit 17. The transport unit 17 transports the medium 30 from upstream to downstream in the transport direction D1. Upstream and downstream in the transport direction D1 are simply referred to as upstream and downstream. The arrow labeled D2 is perpendicular to the transport direction D1 and indicates the width direction D2. The length of the medium 30 in the width direction D2 is called the medium width.
[0021] Figure 2 shows a portion of the print head 18. In Figure 2, each white circle represents an individual nozzle 20. The arrow labeled D3 indicates the nozzle alignment direction D3. In the example in Figure 2, the nozzle alignment direction D3 is parallel to the width direction D2 and perpendicular to the transport direction D1. That is, direction D3 = direction D2. However, in the configuration of the print head 18, the nozzle alignment direction D3 may intersect the width direction D2 at an angle.
[0022] The print head 18 has a nozzle row for each ink color. A nozzle row is composed of multiple nozzles 20 arranged at predetermined intervals along the nozzle arrangement direction D3. This interval is referred to as the "nozzle pitch P". The nozzle pitch P can be understood as the distance between the centers of adjacent nozzles 20 within the nozzle row. For example, with respect to K ink, the print head 18 has multiple nozzle rows such as 19K1, 19K2, 19K3, etc. Each of the nozzle rows 19K1, 19K2, and 19K3 is composed of multiple nozzles 20 for ejecting K ink.
[0023] In this context, a configuration in which multiple nozzle rows for a single color of ink are offset from each other in the nozzle alignment direction D3 is called a nozzle row unit. In other words, in the example in Figure 2, nozzle rows 19K1, 19K2, 19K3… constitute the nozzle row unit for K ink. Similarly, nozzle rows 19C1, 19C2, 19C3… made up of multiple nozzles 20 for ejecting C ink constitute the nozzle row unit for C ink, nozzle rows 19M1, 19M2, 19M3… made up of multiple nozzles 20 for ejecting M ink constitute the nozzle row unit for M ink, and nozzle rows 19Y1, 19Y2, 19Y3… made up of multiple nozzles 20 for ejecting Y ink constitute the nozzle row unit for Y ink.
[0024] Therefore, the print head 18 has nozzle row units for each CMYK ink. As shown in Figure 2, each CMYK nozzle row unit is arranged along the transport direction D1, and their positions coincide or nearly coincide in the width direction D2. Although not shown in Figure 2, each CMYK nozzle row unit has a length in the width direction D2 that can cover the width of the media. In this example, when the media 30, which is transported at a predetermined speed by the transport unit 17, passes under the print head 18 located on the transport path, it receives ink discharge from the print head 18 in the order of C, M, Y, K, and printing is performed on the media 30.
[0025] When focusing on a single nozzle row unit, one adjacent nozzle row in the nozzle arrangement direction D3 is called the "first nozzle row," and the other nozzle row is called the "second nozzle row." The terms "first nozzle row" and "second nozzle row" do not refer to specific nozzle rows, but are merely expressions to distinguish two adjacent nozzle rows. For example, in a K ink nozzle row unit, if nozzle row 19K1 is considered the first nozzle row, then nozzle row 19K2 corresponds to the second nozzle row. Alternatively, if nozzle row 19K2 is considered the first nozzle row, then nozzle row 19K1 or nozzle row 19K3 corresponds to the second nozzle row. The same concept applies to the CMY nozzle row units as well, regarding the first and second nozzle rows.
[0026] According to FIG. 2, in the print head 18 of the first embodiment, the first nozzle row and the second nozzle row do not overlap in the nozzle arrangement direction D3. That is, they do not overlap. A "boundary portion" is provided between the first nozzle row and the second nozzle row. The boundary portion can be regarded as a range where no nozzles 20 that can be used for printing exist. Specifically, a "first adjacent nozzle", which is the nozzle 20 at the end of the first nozzle row on the side of the second nozzle row, and a "second adjacent nozzle", which is the nozzle 20 at the end of the second nozzle row on the side of the first nozzle row, are separated by a distance longer than the nozzle pitch P, whereby a boundary portion 18a is arranged between the first adjacent nozzle and the second adjacent nozzle. "Adjacent nozzle" is a name meaning a nozzle adjacent to the boundary portion.
[0027] For example, when nozzle row 19K1 is the first nozzle row and nozzle row 19K2 is the second nozzle row, the nozzle 20 at the end of nozzle row 19K1 on the side of nozzle row 19K2 corresponds to the first adjacent nozzle 20a, and the nozzle 20 at the end of nozzle row 19K2 on the side of nozzle row 19K1 corresponds to the second adjacent nozzle 20b. According to FIG. 2, the distance between the first adjacent nozzle 20a and the second adjacent nozzle 20b in the nozzle arrangement direction D3 is the distance Q, and P < Q. Also, according to FIG. 2, the position of the boundary portion 18a is common for each nozzle row unit of CMYK.
[0028] Considering the complementation described later, more preferably, the distance Q is 1.5 times or more and 2.0 times or less the nozzle pitch P. According to such a numerical value, the boundary portion 18a can be said to be a gap of about 0.5 to 1.0 nozzles between the first adjacent nozzle and the second adjacent nozzle. Therefore, in the present embodiment, when manufacturing a nozzle row unit by connecting nozzle rows, the distance between the first adjacent nozzle of the first nozzle row and the second adjacent nozzle of the second nozzle row may be connected so as to fall within 1.5 to 2.0 times the nozzle pitch P. Therefore, there is no need to strictly align the positional relationship of the nozzles between the nozzle rows as in the prior art, and the manufacturing process is simplified.
[0029] The control unit 11 causes the print head 18 to eject ink onto the medium 30 based on print data that represents an image. As is well known, the print head 18 has a drive element for each nozzle 20, and the application of a drive signal to the drive element of each nozzle 20 is controlled according to the print data, so that each nozzle 20 ejects a dot or does not eject a dot, thereby printing the image represented by the print data onto the medium 30. The print data is data that defines the presence or absence of dots of each color ink and the size of the dots for each pixel. Hereinafter, having a dot, i.e. ejecting a dot, will also be referred to as "dot on," and not having a dot, i.e. not ejecting a dot, will also be referred to as "dot off."
[0030] By varying the amplitude and shape of the drive signal applied to the drive element of the nozzle 20, the size of the dots ejected by the nozzle 20 can be varied. For example, the nozzle 20 can eject three different sizes of dots: large, medium, and small. The relationship between the sizes of each dot is small < medium < large. Therefore, the dot-on data for each pixel specified in the print data will be divided into large dot-on, medium dot-on, or small dot-on. The nozzle 20 can eject two or more different sizes of dots.
[0031] Figure 3 shows a simplified view of the relationship between the medium 30 and the print head 18 from above. The print head 18 shown in Figure 3 is referred to as the "second embodiment" print head 18. The way to read Figure 3 is the same as in Figure 2, and the differences between the second embodiment print head 18 and the first embodiment print head 18 will be explained.
[0032] According to Figure 3, in the print head 18 of the second embodiment, the end of the first nozzle row on the second nozzle row side and the end of the second nozzle row on the first nozzle row side overlap in the nozzle arrangement direction D3. In other words, they overlap. Specifically, by making the nozzles 20 of the first nozzle row and the nozzles 20 of the second nozzle row located between the first adjacent nozzle and the second adjacent nozzle "unused nozzles" that are not used for ink ejection, a boundary portion 18a is arranged between the first adjacent nozzle and the second adjacent nozzle. In the second embodiment, at least one of the first adjacent nozzle and the second adjacent nozzle does not correspond to the nozzle 20 at the end of the nozzle row to which it belongs.
[0033] Unused nozzles exist as nozzles 20 but are not used for printing. Unused nozzles are not subject to printing data assignment in steps S120 and S130 of Figure 4, which will be described later. In other words, the difference between the second embodiment and the first embodiment is whether or not unused nozzles exist at the boundary 18a. In Figure 3, nozzles 20 corresponding to unused nozzles are indicated by dashed circles. Basically, among the nozzles 20 of the first nozzle row, the nozzles 20 on the second nozzle row side of the first adjacent nozzle are unused nozzles, and among the nozzles 20 of the second nozzle row, the nozzles 20 on the first nozzle row side of the second adjacent nozzle are unused nozzles.
[0034] Here, as an example, nozzle row 19K1 is referred to as the first nozzle row, and nozzle row 19K2 as the second nozzle row. The distance Q is the distance between one nozzle 20 of nozzle row 19K1, which is the first adjacent nozzle 20a, and one nozzle 20 of nozzle row 19K2, which is the second adjacent nozzle 20b. The nozzles 20 of nozzle row 19K1 and nozzles 20 of nozzle row 19K2 that are within this distance Q correspond to unused nozzles 20c at the boundary 18a. When considering the print head 18 of the second embodiment, unless otherwise specified below, nozzles or nozzles 20 refer to nozzles excluding unused nozzles. Naturally, the first adjacent nozzle and the second adjacent nozzle are included in the nozzles excluding unused nozzles. In this embodiment, either the configuration of the first embodiment or the second embodiment may be adopted for the print head 18. The following description will continue without making any particular distinction between the first and second embodiments.
[0035] 3. Print control processing: Figure 4 shows a flowchart illustrating the print control process executed by the control unit 11 according to the program 12. The flowchart represents the printing method according to this embodiment. In step S100, the print data generation unit 12a of the control unit 11 acquires image data representing the image to be printed. The print data generation unit 12a acquires image data specified by the user through an operation of the operation reception unit 14, for example, from an image data storage location such as the storage unit 15 or memory inside or outside the printing device 10. Alternatively, the print data generation unit 12a receives and acquires image data transmitted from an external device via the communication IF 16.
[0036] In step S110, the print data generation unit 12a generates print data based on the image data acquired in step S100. The print data generated in step S110 includes "virtual raster lines".
[0037] First, we will explain the basic process of generating print data based on image data. The print data generation unit 12a performs a resolution conversion process to adjust the number of pixels in the vertical and horizontal directions of the image data to the required number of pixels, according to the size of the media 30 which has been set in advance and the vertical and horizontal printing resolution achieved by the print head 18 and transport unit 17. Here, vertical refers to the transport direction D1 and horizontal refers to the width direction D2.
[0038] Next, the print data generation unit 12a converts the values of each pixel constituting the image data into gradation values that represent the amount of ink of each color used by the print head 18 for printing. The color system used by the image data is not particularly limited, but for example, if the image data is RGB image data with gradation values of red (R), green (G), and blue (B) for each pixel, the print data generation unit 12a refers to a lookup table that defines the conversion relationship between RGB and CMYK and converts each RGB gradation value of each pixel of the image data to each CMYK gradation value. The gradation values are expressed in 256 gradations, for example, from 0 to 255.
[0039] Next, the print data generation unit 12a converts the CMYK gradation values that each pixel of the color-converted image data has into values representing dot-on or dot-off for each CMYK ink through halftone processing. Dot-on can, of course, be large dot-on, medium dot-on, or small dot-on. Thus, the data obtained from the image data acquired in step S100 through predetermined resolution conversion processing, color conversion processing, and halftone processing is the print data.
[0040] In print data, a row of pixels arranged in a direction intersecting the nozzle alignment direction D3, in this case along the transport direction D1, is called a "raster line." The result of printing such a row of pixels onto the medium 30 can also be called a raster line. In the configuration using the print head 18 of the first and second embodiments, one color of ink in one raster line constituting the print data is printed by dot ejection from one nozzle 20 corresponding to that ink. In this embodiment, it is assumed that there is one "virtual nozzle" at one boundary 18a for each CMYK nozzle row unit. Since it is a virtual nozzle, it does not actually exist. The print data generation unit 12a generates raster lines, i.e., virtual raster lines, corresponding to the virtual nozzles. When referring to nozzles or nozzle 20, the virtual nozzles are not included.
[0041] Figure 5 illustrates a portion of the print data 40 corresponding to a single color of ink, for example, K ink. Figure 5 also shows the correspondence between the orientation of the print data 40 and directions D1 and D2. In Figure 5, each rectangle is a pixel that makes up the print data 40. Each pixel has a value that indicates one of the following with respect to the K ink: large dot on, medium dot on, small dot on, or dot off. The raster line 42 consisting of pixels painted in gray is a virtual raster line 42, and the raster line consisting of white pixels, for example, raster line 41, is a normal raster line 41. hmm The term "virtual raster line" is used to distinguish it from virtual raster lines, and it refers to a raster line that is assigned one-to-one to each nozzle 20, including the first adjacent nozzle and the second adjacent nozzle, depending on its position in the width direction D2. The gray and white colors of the pixels in Figure 5 are merely a way to clearly distinguish between virtual raster lines 42 and normal raster lines, and are unrelated to the actual colors of the image.
[0042] Information regarding the configuration of the print head 18, including the boundary portion 18a, is pre-stored in the storage unit 15, and the print data generation unit 12a can refer to this information as needed. Therefore, in step S110, in the process of generating print data based on image data, the print data generation unit 12a assumes a virtual nozzle for the boundary portion 18a in addition to the actual nozzles 20, and generates print data 40 for each ink color, as shown in Figure 5, which includes a normal raster line corresponding to the nozzle 20 and a virtual raster line 42 corresponding to the virtual nozzle. The virtual raster line 42 in the print data 40 is a concrete example of a "complementary image" or "print data for printing the complementary image." Therefore, it can be said that step S110 includes a "setting step" in which a complementary image is set as a part of the image to be printed on the medium 30, corresponding to the boundary portion 18a between the first nozzle row and the second nozzle row.
[0043] In step S120, the print control unit 12b assigns each raster line, including the virtual raster lines that make up the print data generated in step S110, to each nozzle 20 in the CMYK nozzle row unit of the print head 18 according to their position and ink color. Normally, the print control unit 12b assigns each raster line to each nozzle 20. On the other hand, since virtual nozzles do not actually exist, the print control unit 12b assigns virtual raster lines to the first adjacent nozzle or the second adjacent nozzle adjacent to the virtual nozzle. Step S120 corresponds to the "assignment process".
[0044] In step S130, the print control unit 12b executes the output processing of the print data. That is, the print control unit 12b controls the transport unit 17 to start transporting the medium 30 and transfers the data of each raster line constituting the print data to each assigned nozzle 20 according to the assignment in step S120. As a result, dots are ejected from each nozzle 20 of each nozzle row unit of the print head 18 onto the medium 30 according to the value of each pixel of the assigned raster line, and the image represented by the print data is printed onto the medium 30. At this time, the virtual raster lines are printed onto the medium 30 by the ejection of dots by the assigned nozzle 20, which is the first adjacent nozzle or the second adjacent nozzle. In other words, the image to be interpolated is interpolated by the first adjacent nozzle or the second adjacent nozzle as part of the image to be printed. In Figure 4, steps S120 and S130 are described separately, but steps S120 and S130 may be understood as substantially a single process or processes executed in parallel. Furthermore, the division of roles between the print data generation unit 12a and the print control unit 12b is not limited to the above-described configuration.
[0045] Steps S120 and S130 include an "interpolation process." A specific example of the interpolation process will be explained with reference to Figure 6. Figure 6 shows a portion of one virtual raster line 42a and portions of the normal raster lines 41a and 41b adjacent to this virtual raster line 42a. These raster lines 41a, 41b, and 42a are data generated as part of the print data in step S110. In Figure 6, the presence or absence and size of circles in each pixel that makes up the raster lines 41a, 41b, 42a and raster line 41a' represent either large dot-on, medium dot-on, small dot-on, or dot-off.
[0046] Here, it is assumed that the normal raster line 41a is a raster line assigned to the first adjacent nozzle 20a of nozzle row 19K1, and the normal raster line 41b is a raster line assigned to the second adjacent nozzle 20b of nozzle row 19K2. Furthermore, it is assumed that the virtual raster line 42a is a raster line generated in accordance with a virtual nozzle assumed to be at the boundary 18a between the first adjacent nozzle 20a and the second adjacent nozzle 20b. The print control unit 12b assigns the virtual raster line 42a to the first adjacent nozzle 20a, for example.
[0047] For the first adjacent nozzle 20a, there is a normal raster line 41a that should be assigned. Therefore, in step S120, the print control unit 12b assigns a raster line 41a', which is the normal raster line 41a plus a virtual raster line 42a, to the first adjacent nozzle 20a. There are various methods for adding the virtual raster line 42a to the normal raster line 41a to create a raster line 41a', but basically, the print control unit 12b can generate the raster line 41a' by adding the pixel values of pixels whose positions in the transport direction D1 coincide.
[0048] For example, adding one of the following to dot off: large dot on, medium dot on, or small dot on, will result in large dot on, medium dot on, or small dot on in the raster line 41a'. Also, for example, adding small dot on to small dot on results in medium dot on. Also, for example, adding medium dot on to small dot on results in large dot on. Note that for a single color, a dot larger than a large dot cannot be formed in a single pixel. Therefore, medium dot on + medium dot on, medium dot on + large dot on, and large dot on + large dot on all result in large dot on. However, if the print control unit 12b specifies large dot on as a result of medium dot on + large dot on or large dot on + large dot on for a pixel in the raster line 41a', it may diffuse the excess ink to other pixels in the raster line 41a' to increase the size of the dots in those pixels.
[0049] In the example shown in Figure 6, in step S130, the print control unit 12b transfers the data of the raster line 41a' to the first adjacent nozzle 20a and the data of the normal raster line 41b to the second adjacent nozzle 20b. As a result, dots are ejected from the first adjacent nozzle 20a onto the medium 30 according to the value of each pixel of the raster line 41a', and dots are ejected from the second adjacent nozzle 20b onto the medium 30 according to the value of each pixel of the normal raster line 41b. In other words, more ink is ejected from the first adjacent nozzle 20a than when the values of each pixel of the normal raster line 41a are used, due to the addition of the virtual raster line 42a. Therefore, the dots ejected from the first adjacent nozzle 20a onto the medium 30 spread and bleed into an area of the medium 30 corresponding to the distance Q, which is the distance between the first adjacent nozzle 20a and the second adjacent nozzle 20b, and as a result, the virtual raster line 42a is complemented by the first adjacent nozzle 20a. Of course, the print control unit 12b may assign the virtual raster line 42a to the second adjacent nozzle 20b instead of the first adjacent nozzle 20a.
[0050] Furthermore, the timing for assigning the virtual raster line data to the first or second adjacent nozzle does not necessarily have to be after generating print data in a format that defines the on / off state of each pixel's dots. For example, the control unit 11 adds the gradation value of each pixel of the virtual raster line in the image data, which has CMYK gradation values for each pixel before halftone processing, to the gradation value of each pixel of either of the two adjacent normal raster lines in the width direction D2, and then sets the gradation value of all pixels in the virtual raster line to 0. Then, it applies halftone processing to the image data after this addition process to generate print data. In such print data, for example, the on / off state of the dots of the normal raster line corresponding to the first adjacent nozzle is determined with the ink amount of the adjacent virtual raster line included, so the virtual raster line is effectively assigned to the first adjacent nozzle. For convenience, the embodiments described so far will be referred to as the First Embodiment. In the following embodiments, explanations common to the First Embodiment will be omitted as appropriate.
[0051] 4. Second Embodiment: The second embodiment is a modification of the second embodiment described in Figure 3. In the print head 18 of the second embodiment, the first nozzle row and the second nozzle row partially overlap, so there is flexibility in the positions of the boundary, the first adjacent nozzle, and the second adjacent nozzle. Therefore, in the second embodiment, the boundary may be positioned such that a "defective nozzle" with poor ink ejection in the first or second nozzle row is included in the unused nozzles.
[0052] A defective nozzle is a nozzle 20 that is unable to eject ink at all or not ejecting ink properly due to nozzle clogging or the like. A defective nozzle may also be called an abnormal nozzle. The configuration and method for detecting defective nozzles are publicly known and will not be described here. In any case, the control unit 11 can recognize a defective nozzle in the print head 18. By including the defective nozzle as one of the unused nozzles at the boundary, it is possible to avoid the defective nozzle affecting the print result.
[0053] Figures 7A, 7B, 7C, and 7D each illustrate the position of the boundary portion 18a in the print head 18 according to the second embodiment. Figures 7A, 7B, 7C, and 7D all focus on the boundary portion 18a between nozzle row 19K1 and nozzle row 19K2, and the way to read the figures is the same as in Figure 3. The boundary portions 18a shown in Figures 7A, 7B, 7C, and 7D differ in their position in the nozzle arrangement direction D3. As in Figure 3, unused nozzles are indicated by dashed circles, and defective nozzles 20d are further colored gray for clarity. Defective nozzles 20d also serve as unused nozzles. Incidentally, the boundary portion 18a shown in Figure 7A is the same as the boundary portion 18a of nozzle rows 19K1 and 19K2 shown in Figure 3.
[0054] In other words, the control unit 11 recognizes the position of the defective nozzle 20d in the nozzle row unit of the print head 18, and sets a boundary 18a that includes the position of the defective nozzle 20d, and a first adjacent nozzle 20a and a second adjacent nozzle 20b adjacent to this boundary 18a. The distance between the first adjacent nozzle 20a in nozzle row 19K1 and the second adjacent nozzle 20b in nozzle row 19K2, which straddle the boundary 18a, is distance Q. Then, the control unit 11 generates a virtual raster line corresponding to the virtual nozzle assumed in the boundary 18a determined in this way, and executes the interpolation process described above.
[0055] Depending on the location of the defective nozzle in the nozzle row unit, it may not be possible to set a boundary that includes the location of the defective nozzle. Therefore, if it is possible to set a boundary that includes the location of the defective nozzle and the first and second adjacent nozzles adjacent to this boundary, the control unit 11 should adopt the second embodiment. Otherwise, as shown in the example in Figure 3, the control unit 11 should set the boundary 18a and the first and second adjacent nozzles 20a and 20b adjacent to the boundary 18a independently of the defective nozzle.
[0056] 5. Third Embodiment: As shown in Figures 2 and 3, the print head 18 is capable of ejecting multiple colors of ink and has a first nozzle row and a second nozzle row for each ink color. In Figures 2 and 3, the position of the boundary portion 18a is common between the CMYK nozzle row units. However, the boundary portions may be positioned at offset locations in the nozzle arrangement direction D3 for each ink color.
[0057] Figure 8 shows a simplified view of the print head 18 according to the third embodiment, from the same viewpoint as in Figures 2 and 3. The print head 18 in Figure 8 differs from the print head 18 in Figure 2 in that the position of the boundary portion 18a is shifted in the nozzle alignment direction D3 for each CMYK nozzle row unit. With this configuration, it is possible to complement an image to be complemented by one ink color with another ink color. In Figure 8, each nozzle 20 of each CMY nozzle row unit, where the position of the boundary portion 18a of nozzle rows 19K1 and 19K2 is the same or nearly the same in the nozzle alignment direction D3, is enclosed by a dashed line and shown as a nozzle group 21.
[0058] The control unit 11 assigns, for example, at least some of the dots of the virtual raster lines of the K ink generated corresponding to the virtual nozzles at the boundary portion 18a of the nozzle rows 19K1 and 19K2 to each nozzle 20 of the nozzle group 21. This allows the virtual raster lines to be complemented not only by the first adjacent nozzle 20a or the second adjacent nozzle 20b described earlier, but also by the nozzle group 21. In particular, the nozzle group 21 allows the virtual raster lines of the K ink to be complemented by the composite black produced by mixing the CMY inks. Furthermore, according to this third embodiment, the virtual raster lines of each CMY can also be complemented to some extent by inks of different colors. Although not shown in the figures, the third embodiment is naturally applicable to configurations in which the first nozzle row and the second nozzle row partially overlap for each ink color, as shown in Figures 3 and 7A.
[0059] 6. Fourth Embodiment: The print head 18 described so far is a non-moving type of head, but in the fourth embodiment, the print head 18 is movable along the main scanning direction D4 which intersects the nozzle alignment direction D3. In other words, the print head 18 is mounted on a so-called carriage that moves back and forth along the main scanning direction D4 with the power of a motor, and moves together with the carriage.
[0060] Figure 9 shows a simplified view from above of the relationship between the medium 30 and the print head 18 according to the fourth embodiment. The main scanning direction D4 is perpendicular to the transport direction D1. The main scanning direction D4 can be understood to be the same as the width direction D2 described in Figures 2, 3, 5, 6, etc. In Figure 9, the nozzle alignment direction D3 is parallel or nearly parallel to the transport direction D1. In Figure 9, each white circle represents an individual nozzle 20.
[0061] In Figure 9, the print head 18 has nozzle rows 19C, 19M, 19Y, and 19K for each ink color. Nozzle row 19C consists of multiple nozzles 20 for ejecting C ink, arranged along the nozzle arrangement direction D3. Similarly, nozzle row 19M consists of multiple nozzles 20 for ejecting M ink, nozzle row 19Y consists of multiple nozzles 20 for ejecting Y ink, and nozzle row 19K consists of multiple nozzles 20 for ejecting K ink. The respective CMYK nozzle rows 19C, 19M, 19Y, and 19K are arranged along the main scanning direction D4, and their positions coincide in the transport direction D1.
[0062] The control unit 11 causes the print head 18 to execute a "path" in which ink is ejected from each nozzle 20 to the medium 30 based on the print data as the print head 18 moves with the carriage. In Figure 9, the carriage is not shown. Alternatively, the print head 18 in Figure 9 can be understood as also serving as the carriage. The path may also be called a "scan". In other words, the control unit 11 prints the image represented by the print data onto the medium 30 by alternately repeating the path and the transport unit 17 transporting the medium 30 over a fixed distance. The transport over a fixed distance is called "paper feeding". In this fourth embodiment, the pixel row, which is a row of pixels arranged along the main scanning direction D4 that intersects the nozzle alignment direction D3, is a raster line.
[0063] In Figure 9, the "N" and "N+1" written in parentheses near the symbol "18" indicate which pass the print head 18 is making on the medium 30. N is an integer greater than or equal to 1. In other words, Figure 9 shows the positional relationship between the print head 18 and the medium 30 as it performs the Nth pass, the N+1th pass, and the N+2nd pass, respectively. In Figure 9, it appears as though the print head 18 is moving upstream with each increase in the number of passes, but in reality, the transport unit 17 feeds paper between passes, changing the positional relationship between the medium 30 and the print head 18 in the transport direction D1.
[0064] In the fourth embodiment, the pass executed before the paper feed is called the "first pass," and the pass executed afterward is called the "second pass." According to Figure 9, for example, if the Nth pass is considered the first pass, then the N+1th pass corresponds to the second pass. Similarly, if the N+1th pass is considered the first pass, then the N+2nd pass corresponds to the second pass. In the fourth embodiment, a "boundary portion 18b" is secured between the position of the nozzle row 18 when the first pass is executed and the position of the nozzle row 18 when the second pass is executed on the medium 30. In other words, in Figures 2, 3, 8 and 7A described so far, the boundary portion 18a exists as a part of the print head 18, but in the fourth embodiment, the boundary portion 18b is considered to occur on the medium 30 due to the relative positional change between the print head 18 and the medium 30 in the transport direction D1. Specifically, the boundary portion 18b is secured by making the distance of one paper feed by the transport unit 17 longer by a distance Q than the length of the nozzle row in the transport direction D1. Here, the length of the nozzle row in the transport direction D1 is considered to be the distance between the downstream nozzle 20 and the upstream nozzle 20 of the nozzle row.
[0065] For example, focusing on the nozzle row 19K of the print head 18, the upstream nozzle 20 is called the first adjacent nozzle 20a, and the downstream nozzle 20 is called the second adjacent nozzle 20b. According to Figure 9, a boundary 18b is secured between the first adjacent nozzle 20a of nozzle row 19K during the execution of the first pass and the second adjacent nozzle 20b of nozzle row 19K during the execution of the second pass. The concept of the first adjacent nozzle and the second adjacent nozzle adjacent to the boundary 18b is the same for the other nozzle rows 19C, 19M, and 19Y.
[0066] In step S110, the control unit 11 assumes a virtual nozzle at the boundary 18b and generates a virtual raster line as a portion of the image to be printed on the medium 30, corresponding to the virtual nozzle. Then, in steps S120 and S130, the control unit 11 assigns the virtual raster line, which is the print data for printing the image to be completed, to the first adjacent nozzle 20a adjacent to the boundary 18b during the execution of the first pass, or to the second adjacent nozzle 20b adjacent to the boundary 18b during the execution of the second pass. Based on the assigned virtual raster line, the image to be completed is completed by ink ejection from the first adjacent nozzle 20a or the second adjacent nozzle 20b. In other words, printing on the boundary 18b is completed by ink ejection from the first adjacent nozzle 20a in the first pass or by ink ejection from the second adjacent nozzle 20b in the second pass.
[0067] In Figure 9, the positions of the nozzle rows during the first pass and the positions of the nozzle rows during the second pass do not overlap in the transport direction D1 near the boundary 18b; therefore, Figure 9 can be considered the first embodiment of the fourth embodiment. Of course, in the fourth embodiment as well, the second embodiment may be adopted in which the positions of the nozzle rows during the first pass and the positions of the nozzle rows during the second pass in the medium 30 partially overlap while the boundary 18b is secured by unused nozzles. Also, in the fourth embodiment as well, the position of the boundary 18b in the transport direction D1 may differ for each CMYK nozzle row.
[0068] 7. Summary: As described above, according to this embodiment, the printing apparatus 10 includes a print head 18 having a first nozzle row in which a plurality of nozzles 20 are arranged in the nozzle arrangement direction D3, and a second nozzle row in which a plurality of nozzles 20 are arranged offset from the first nozzle row in the nozzle arrangement direction D3, and the nozzles 20 are arranged in the nozzle arrangement direction D3; and a control unit 11 that controls the ejection of ink from the nozzles 20 of the print head 18 to the medium 30 based on print data. The control unit 11 sets a target image to be completed as a part of the image to be printed on the medium 30, corresponding to the boundary portion 18a between the first nozzle row and the second nozzle row, and assigns print data for printing the target image to a first adjacent nozzle 20a of the first nozzle row adjacent to the boundary portion 18a, or a second adjacent nozzle 20b of the second nozzle row adjacent to the boundary portion 18a, and completes the target image by ejecting ink from the first adjacent nozzle 20a or the second adjacent nozzle 20b based on the assigned print data.
[0069] According to the above configuration, the interpolation target image, which is set in accordance with the boundary portion 18a between the first nozzle row and the second nozzle row, is interpolated by ink ejection from the first adjacent nozzle 20a or the second adjacent nozzle 20b adjacent to the boundary portion 18a. Therefore, it is possible to eliminate the density differences and density unevenness in the print result caused by using overlapping and non-overlapping portions of nozzle rows in printing. Furthermore, in a configuration in which overlapping and non-overlapping portions of nozzle rows coexist, the density differences in the print result tend to vary from one printing device 10 to another, but according to this embodiment, such product-to-product variations can also be eliminated.
[0070] Furthermore, according to this embodiment, when the nozzle pitch P is defined as the distance between the nozzles 20 in the first nozzle row or the distance between the nozzles 20 in the second nozzle row in the nozzle arrangement direction D3, the boundary portion 18a may be positioned between the first adjacent nozzle 20a, which is the nozzle 20 at the end of the first nozzle row on the second nozzle row side, and the second adjacent nozzle 20b, which is the nozzle 20 at the end of the second nozzle row on the first nozzle row side, by a distance Q that is longer than the nozzle pitch P. According to the above configuration, the first nozzle row and the second nozzle row are actually separated by a distance longer than the nozzle pitch P. Therefore, it is possible to reliably eliminate density differences and density unevenness in the printed result caused by the coexistence of overlapping and non-overlapping portions of conventional nozzle rows. Furthermore, when printing on the medium 30, the length of each nozzle row can be utilized to the maximum extent, so it is possible to print with fewer nozzle rows for a larger medium width.
[0071] Furthermore, according to this embodiment, the end of the first nozzle row on the second nozzle row side and the end of the second nozzle row on the first nozzle row side overlap in the nozzle arrangement direction D3, and when the distance between the nozzles 20 of the first nozzle row or the distance between the nozzles 20 of the second nozzle row in the nozzle arrangement direction D3 is defined as the nozzle pitch P, the first adjacent nozzle 20a and the second adjacent nozzle 20b are separated by a distance Q that is longer than the nozzle pitch P, and the boundary portion 18a may be positioned between the first adjacent nozzle 20a and the second adjacent nozzle 20b by making the nozzles of the first nozzle row and the nozzles of the second nozzle row located between the first adjacent nozzle 20a and the second adjacent nozzle 20b unused nozzles that are not used for ink ejection. According to the above configuration, the first nozzle row and the second nozzle row overlap in part, but the first adjacent nozzle 20a and the second adjacent nozzle 20b are separated by a distance longer than the nozzle pitch P, and the nozzle between the first adjacent nozzle 20a and the second adjacent nozzle 20b is an unused nozzle 20c. Therefore, from a printing perspective, the first nozzle row and the second nozzle row do not overlap in substance, and the density differences and density unevenness in the printing result caused by the coexistence of overlapping and non-overlapping parts of conventional nozzle rows can be reliably eliminated.
[0072] Furthermore, according to this embodiment, the boundary portion 18a may be arranged such that a defective nozzle in the first or second nozzle row, which has poor ink ejection, is included in the unused nozzles. According to the above configuration, by including the defective nozzles in the unused nozzles of the boundary portion 18a, it is possible to avoid the decrease in print quality that occurs when defective nozzles are used for printing.
[0073] Furthermore, according to this embodiment, the print head 18 is capable of ejecting multiple colors of ink, and has a first nozzle row and a second nozzle row for each ink color. The boundary portion 18a may be positioned at a staggered position in the nozzle arrangement direction D3 for each ink color. According to the above configuration, it is possible to complement an image of a certain color using ink of another color.
[0074] Furthermore, according to this embodiment, the printing apparatus 10 includes a print head 18 that has a nozzle row in which multiple nozzles 20 are arranged in the nozzle arrangement direction D3 and is movable along a main scanning direction D4 that intersects the nozzle arrangement direction D3, and a control unit 11 that causes the print head 18 to execute a pass in which ink is ejected from the nozzles 20 to the medium 30 based on the print data as the movement occurs.The control unit 11 sets a target image to be completed as a part of the image to be printed on the medium 30, corresponding to the boundary 18b between the position of the nozzle row in the medium 30 when the first pass is executed and the position of the nozzle row when the second pass following the first pass is executed, assigns print data for printing the target image to a first adjacent nozzle 20a in the nozzle row According to the above configuration, the interpolation target image set in correspondence with the boundary portion 18b is interpolated by ink ejection from the first adjacent nozzle 20a or the second adjacent nozzle 20b adjacent to the boundary portion 18b. Therefore, it is possible to eliminate density differences and density unevenness in the printing result caused by the coexistence of overlapping portions and non-overlapping portions between the printing by the nozzle row of the first pass and the printing by the nozzle row of the second pass on the medium. Furthermore, in a configuration in which overlapping portions and non-overlapping portions coexist in the printing result, the density differences between them tend to vary from one printing apparatus 10 to another, but according to this embodiment, such product-to-product variations can also be eliminated.
[0075] This embodiment discloses inventions in various categories, not limited to devices or systems, but also including methods executed by devices or systems, and programs 12 that cause a processor to execute these methods. For example, a printing method for ejecting ink from nozzles 20 onto a medium 30 by controlling a print head 18 having a first nozzle row in which multiple nozzles 20 are arranged in the nozzle arrangement direction D3 and a second nozzle row in which multiple nozzles 20 are arranged offset from the first nozzle row in the nozzle arrangement direction D3, based on print data, includes a setting step of setting a target image to be completed as a part of the image to be printed on the medium 30, corresponding to the boundary portion 18a between the first nozzle row and the second nozzle row; an assignment step of assigning print data for printing the target image to a first adjacent nozzle 20a of the first nozzle row that is adjacent to the boundary portion 18a or a second adjacent nozzle 20b of the second nozzle row that is adjacent to the boundary portion 18a; and a completion step of completing the target image by ejecting ink from the first adjacent nozzle 20a or the second adjacent nozzle 20b based on the assigned print data.
[0076] Furthermore, a printing method in which a print head 18 having a nozzle row in which multiple nozzles 20 are arranged in the nozzle arrangement direction D3 is moved along a main scanning direction D4 that intersects the nozzle arrangement direction D3, and ink is ejected from the nozzles 20 to the medium 30 based on print data, includes a setting step of setting a target image to be completed as a part of the image to be printed on the medium 30, corresponding to the boundary 18b between the position of the nozzle row when the first pass is executed on the medium 30 and the position of the nozzle row when the second pass following the first pass is executed; an assignment step of assigning print data for printing the target image to a first adjacent nozzle 20a of the nozzle row when the first pass is executed that is adjacent to the boundary 18b, or to a second adjacent nozzle 20b of the nozzle row when the second pass is executed that is adjacent to the boundary 18b; and a completion step of completing the target image by ejecting ink from the first adjacent nozzle 20a or the second adjacent nozzle 20b based on the assigned print data.
[0077] As explained above, by assigning the print data for printing the interpolated image to either the first adjacent nozzle 20a or the second adjacent nozzle 20b, the interpolated image can be printed using either the first adjacent nozzle 20a or the second adjacent nozzle 20b. Therefore, in the overall print result of the image, raster lines printed with one nozzle 20 and raster lines printed with two nozzles 20 do not coexist, effectively suppressing density unevenness.
[0078] However, it is also possible to divide the print data for printing the image to be interpolated into a predetermined ratio and allocate it to the first adjacent nozzle 20a and the second adjacent nozzle 20b. The predetermined ratio referred to here is preferably a ratio that is biased towards one side, such as 10% to 90% or 80% to 20%, rather than an equal ratio such as 50% to 50%. Including this configuration, the control unit 11 assigns print data for printing the image to be completed to at least one of the first adjacent nozzle 20a of the first nozzle row adjacent to the boundary portion 18a and the second adjacent nozzle 20b of the second nozzle row adjacent to the boundary portion 18a, and completes the image to be completed by ejecting ink from at least one of the first adjacent nozzle 20a and the second adjacent nozzle 20b based on the assigned print data. Furthermore, the control unit 11 assigns print data for printing the image to be completed to at least one of the first adjacent nozzle 20a, which is a nozzle 20 in the nozzle row during the execution of the first pass and adjacent to the boundary portion 18b, and the second adjacent nozzle 20b, which is a nozzle 20 in the nozzle row during the execution of the second pass and adjacent to the boundary portion 18b, and completes the image to be completed by ejecting ink from at least one of the first adjacent nozzle 20a and the second adjacent nozzle 20b based on the assigned print data.
[0079] Furthermore, from the perspective of complementing the printing corresponding to the boundary with a nearby nozzle 20, the nozzle 20 to which the image to be complemented is assigned may include not only the first adjacent nozzle, but also the nozzle 20 adjacent to the first adjacent nozzle on the opposite side of the boundary, and similarly, not only the second adjacent nozzle, but also the nozzle 20 adjacent to the second adjacent nozzle on the opposite side of the boundary. [Explanation of Symbols]
[0080] 10...Printing device, 11...Control unit, 12...Program, 12a...Print data generation unit, 12b...Print control unit, 13...Display unit, 14...Operation reception unit, 15...Storage unit, 16...Communication IF, 17...Transport unit, 18...Print head, 18a,18b...Boundary unit, 19K,19C,19M,19Y,19K1,19K2,19K3,19C1,19C2,19C3,19M1,19M2,19M3,19Y1,19Y2,19Y3...Nozzle row, 20...Nozzle, 20a...First adjacent nozzle, 20b...Second adjacent nozzle, 20c...Unused nozzle, 20d...Defective nozzle, 21...Nozzle group, 30...Media, 40...Print data, 41,41a,41b...Normal raster line, 42,42a...Virtual raster line
Claims
1. A print head having a first nozzle row in which multiple nozzles are arranged in the nozzle alignment direction, and a second nozzle row in which multiple nozzles are arranged offset from the first nozzle row in the nozzle alignment direction, The print head comprises a control unit that controls the ejection of ink from the nozzles to the medium based on print data, The control unit, As a portion of the image to be printed on the aforementioned medium, a complementary image is set corresponding to the boundary between the first nozzle row and the second nozzle row. The print data for printing the aforementioned complementary image is assigned to at least one of the nozzles in the first nozzle row adjacent to the boundary and the nozzles in the second nozzle row adjacent to the boundary. The image to be completed is completed by ejecting ink from at least one of the first adjacent nozzle and the second adjacent nozzle based on the assigned print data. When the distance between the nozzles in the first nozzle row or the distance between the nozzles in the second nozzle row in the direction of the nozzle arrangement is defined as the nozzle pitch, The printing apparatus is characterized in that the boundary portion is positioned between the first adjacent nozzle, which is the nozzle at the end of the first nozzle row on the second nozzle row side, and the second adjacent nozzle, which is the nozzle at the end of the second nozzle row on the first nozzle row side, by a distance greater than the nozzle pitch.
2. A print head having a first nozzle row in which multiple nozzles are arranged in the nozzle alignment direction, and a second nozzle row in which multiple nozzles are arranged offset from the first nozzle row in the nozzle alignment direction, The print head comprises a control unit that controls the ejection of ink from the nozzles to the medium based on print data, The control unit, As a portion of the image to be printed on the aforementioned medium, a complementary image is set corresponding to the boundary between the first nozzle row and the second nozzle row. The print data for printing the aforementioned complementary image is assigned to at least one of the nozzles in the first nozzle row adjacent to the boundary and the nozzles in the second nozzle row adjacent to the boundary. The image to be completed is completed by ejecting ink from at least one of the first adjacent nozzle and the second adjacent nozzle based on the assigned print data. The end of the first nozzle row on the side of the second nozzle row and the end of the second nozzle row on the side of the first nozzle row overlap in the direction of nozzle arrangement. When the distance between the nozzles in the first nozzle row or the distance between the nozzles in the second nozzle row in the direction of the nozzle arrangement is defined as the nozzle pitch, the distance between the first adjacent nozzle and the second adjacent nozzle is longer than the nozzle pitch. The boundary portion is characterized in that it is located between the first adjacent nozzle and the second adjacent nozzle, by making the nozzles of the first nozzle row and the nozzles of the second nozzle row located between the first adjacent nozzle and the second adjacent nozzle unused nozzles that are not used for ink ejection.
3. The printing apparatus according to claim 2, characterized in that the boundary portion is arranged such that a defective nozzle in the first or second nozzle row that has poor ink ejection is included in the unused nozzles.
4. A print head having a nozzle row in which multiple nozzles are arranged in the nozzle arrangement direction, and which is movable along a main scanning direction that intersects the nozzle arrangement direction, The system includes a control unit that causes the print head to execute a path for ejecting ink from the nozzle to the medium based on the print data as it moves, The control unit, The interpolation target image is set as a partial region of the image to be printed on the medium, corresponding to the boundary between the position of the nozzle row during the execution of the first pass on the medium and the position of the nozzle row during the execution of the second pass following the first pass. The print data for printing the aforementioned complementary image is assigned to at least one of the nozzles in the nozzle row during the execution of the first pass that is adjacent to the boundary and the nozzles in the nozzle row during the execution of the second pass that is adjacent to the boundary. A printing apparatus characterized by complementing the image to be complemented by ejecting ink from at least one of the first adjacent nozzle and the second adjacent nozzle based on the assigned print data.
5. A printing method comprising printing by moving a print head having a nozzle row in which multiple nozzles are arranged in the nozzle arrangement direction along a main scanning direction that intersects the nozzle arrangement direction, and ejecting ink from the nozzles onto the medium based on print data, A setting step of setting an image to be interpolated as a partial region of the image to be printed on the medium, corresponding to the boundary between the position of the nozzle row during the execution of the first pass on the medium and the position of the nozzle row during the execution of the second pass following the first pass; A method for assigning print data for printing the complementary image to at least one of the nozzles in the nozzle row during the execution of the first pass that is adjacent to the boundary and the nozzles in the nozzle row during the execution of the second pass that is adjacent to the boundary, A printing method characterized by comprising a interpolation step of interpolating the image to be interpolated by ejecting ink from at least one of the first adjacent nozzle and the second adjacent nozzle based on the assigned print data.