Printer and printing method

Abstract

To provide a printing technique suitable for printing onto a cloth by liquid discharge.SOLUTION: A printer 1 performs printing by discharging a liquid onto a medium 90 that is a cloth which is woven by use of a first yarn in a first direction and a second yarn in a second direction crossing the first direction. The printer has: a comparison part 140 that compares sizes of respective ranges of the first yarn and the second yarn per unit area on a surface of the medium 90 onto which the liquid is discharged; and a printing control part 110 which controls printing based on image data. In the case where the range of the first yarn per unit area is larger than the range of the second yarn, the printing control part 110 controls printing based on the image data so that a discharge quantity of liquid dots arranged in the first direction decreases compared to the case where the range of the first yarn per unit area is not larger than the range of the second yarn.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] There is a known technique for printing an image onto a recording medium by ejecting ink. In this regard, Patent Document 1 discloses a technique for suppressing bleeding by controlling the size of dots of liquid ejected onto paper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-107687 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been an increasing need for printing images on fabrics. However, Patent Document 1 merely discloses a technology that focuses on suppressing bleeding when printing images on paper. For this reason, there is a need for a printing technology that is suitable for printing on fabrics by ejecting liquid. Although Patent Document 1 mentions processing that takes into account the fiber direction of the medium, because fabrics have warp and weft threads, when fabrics are used as a medium, it is not clear which thread direction the fiber direction refers to. For this reason, it can be said that Patent Document 1 does not take into account printing images on fabrics. [Means for solving the problem]

[0005] The printing device of the present disclosure is a printing device that prints by ejecting liquid onto a medium that is a fabric woven using a first thread in a first direction and a second thread in a second direction that intersects the first direction, and has a comparison unit that compares the size of the range of the first thread and the second thread that occupy per unit area on the surface of the medium onto which the liquid is ejected, and a printing control unit that controls printing based on image data, and the printing control unit controls printing based on the image data so that when the range of the first thread that occupies per unit area is larger than the range of the second thread, the ejection amount of the liquid dots aligned in the first direction is reduced compared to when the range of the first thread that occupies per unit area is not larger than the range of the second thread.

[0006] The printing method disclosed herein is a printing method that prints by ejecting a liquid onto a medium that is a fabric woven using a first thread in a first direction and a second thread in a second direction that intersects the first direction, and compares the size of the range of the first thread and the second thread that occupy per unit area on the surface of the medium onto which the liquid is ejected, and controls printing based on image data, and in controlling the printing, when the range of the first thread that occupies per unit area is larger than the range of the second thread, controls the printing based on the image data so that the amount of liquid dots that are ejected in the first direction is reduced compared to when the range of the first thread that occupies per unit area is not larger than the range of the second thread. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration example of a printing apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating a configuration example of a carriage of a printing apparatus according to an embodiment. [Figure 3] 1 is a block diagram illustrating an example of a configuration of a printing apparatus according to an embodiment. [Figure 4] FIG. 1 is a schematic diagram showing the warp and weft threads of a plain weave fabric. [Figure 5]FIG. 1 is a schematic diagram showing the warp and weft threads of a satin weave fabric. [Figure 6] 10 is a flowchart illustrating an example of a process flow for print control according to a comparison result of a comparison unit. [Figure 7] 10A and 10B are schematic diagrams illustrating examples of printing when ejection from nozzles is restricted. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In addition, the same elements in each drawing are designated by the same reference numerals, and duplicate explanations have been omitted as necessary.

[0009] FIG. 1 is a schematic diagram showing an example of the configuration of a printing device 1 according to an embodiment. FIG. 2 is a schematic diagram showing an example of the configuration of a carriage 41 of the printing device 1. FIG. 3 is a block diagram showing the configuration of the printing device 1. In the coordinates shown in FIGS. 1 and 2, the Z axis is the up-down direction, the +Z direction is the upward direction, the X axis is the forward-backward direction, the -X direction is the forward direction, the Y axis is the left-right direction, the +Y direction is the leftward direction, and the XY plane is the horizontal plane. The printing device 1 will be described below with reference to FIGS. 1 to 3 as appropriate.

[0010] The printing device 1 is an inkjet printer that prints an image on a medium 90. In the exemplary configuration shown in FIG. 1, the printing device 1 prints an image on a long, rolled medium 90 that is set in the printer. In this embodiment, the medium 90 is transported in the +Y direction in the figure. For this reason, the Y-axis direction (particularly the +Y direction) may also be referred to as the transport direction. Also, as will be described later, in this embodiment, an image is printed on the medium 90 by a print head unit 20 that can scan in the X-axis direction. For this reason, the X-axis direction may also be referred to as the scanning direction. The printing device 1 prints on the medium 90 in accordance with print data generated from image data of the image to be printed on the medium 90.

[0011] In this embodiment, the medium 90 is a fabric woven using first yarns in a first direction and second yarns in a second direction intersecting the first direction. More specifically, the medium 90 is a fabric woven using warp yarns (vertical yarns) and weft yarns (horizontal yarns). That is, the first direction and second direction described above are the warp direction and the weft direction. Therefore, the first direction and the second direction are basically perpendicular to each other, but they do not have to be strictly perpendicular to each other. In the present disclosure, perpendicular may include an intersection that deviates from perfect perpendicularity within a predetermined tolerance range.

[0012] Furthermore, in this embodiment, the medium 90 is set in the printing device 1 so that the direction of the warp threads of the medium 90 is aligned with the transport direction (Y-axis direction). In other words, the medium 90 is set in the printing device 1 so that the direction of the weft threads of the medium 90 is aligned with the scanning direction (X-axis direction). This can also be explained as the medium 90 being set in the printing device 1 so that the direction of the warp threads of the medium 90 matches the transport direction, or the medium 90 being set in the printing device 1 so that the direction of the weft threads of the medium 90 matches the scanning direction, but the two directions do not necessarily have to match exactly. In other words, in this disclosure, "the two directions are aligned" can include a state in which the two directions deviate from perfect alignment within a predetermined tolerance range.

[0013] The printing device 1 is composed of a print head unit 20, a camera 30, a scanning unit 40, a transport unit 50, a processing device 10, etc. The processing device 10 generates print data from input image data, and controls the print head unit 20, the scanning unit 40, and the transport unit 50 based on the generated print data to print an image on a medium 90.

[0014] The print head unit 20 ejects dots of liquid onto the medium 90 in order to form an image on the medium 90, i.e., to print an image on the medium 90. Specifically, the print head unit 20 includes one or more heads each having a nozzle row configured with a plurality of nozzles that eject ink droplets arranged at regular intervals.

[0015] In the present embodiment, as an example, the print head unit 20 includes a head 21K, a head 21C, a head 21M, and a head 21Y, as shown in FIG. 2. FIG. 2 is a schematic diagram of a carriage 41, described later, viewed from below. Here, head 21K is a head that ejects black ink, head 21C is a head that ejects cyan ink, head 21M is a head that ejects magenta ink, and head 21Y is a head that ejects yellow ink. Head 21K has a nozzle row consisting of N nozzles 22K (N is an integer) that are continuously aligned in the Y-axis direction. Similarly, head 21C also has a nozzle row consisting of N nozzles 22C that are continuously aligned in the Y-axis direction, head 21M also has a nozzle row consisting of N nozzles 22M that are continuously aligned in the Y-axis direction, and head 21Y also has a nozzle row consisting of N nozzles 22Y that are continuously aligned in the Y-axis direction. It should be noted that the print head unit 20 may include more heads to enable the ejection of more colors.

[0016] As described above, in this embodiment, the nozzle rows of heads 21K, 21C, 21M, and 21Y are arranged along the transport direction (Y-axis direction). This can also be explained as meaning that the arrangement direction of the nozzle rows of heads 21K, 21C, 21M, and 21Y coincides with the transport direction (Y-axis direction), but the two directions do not necessarily have to strictly coincide. Also, as described above, in this embodiment, the medium 90 is set in the printing device 1 so that the direction of the warp threads of the medium 90 is along the transport direction. Therefore, it can also be said that the medium 90 is set in the printing device 1 so that the direction of the warp threads is along the arrangement direction of the nozzle rows. Note that in FIG. 2, the nozzles of each head are arranged in a staggered pattern along a predetermined direction (Y-axis direction), but the nozzles of each head do not necessarily have to be arranged in a staggered pattern as long as they are aligned along the predetermined direction. For example, the nozzles may be arranged in a straight line. In the following description, the head 21K, the head 21C, the head 21M, and the head 21Y may be collectively referred to as the head 21.

[0017] The print head unit 20 is mounted on a carriage 41, and when printing, moves back and forth in the X-axis direction along with the carriage 41, which moves in the X-axis direction (the scanning direction). The head 21 provided on the print head unit 20 mounted on the carriage 41 ejects ink droplets onto the medium 90 supported by the platen 54 while moving in the X-axis direction under the control of the print control unit 110 of the processing device 10, thereby forming a partial image on the medium 90. By combining the printing of the partial image by moving the print head unit 20 in the X-axis direction with the transport of the medium 90 in the Y-axis direction (the transport direction), an image represented by image data is printed on the medium 90.

[0018] The camera 30 captures an image of the surface of the medium 90. More specifically, the camera 30 captures an image of the surface of the medium 90 onto which the liquid (ink) is ejected. In other words, the camera 30 captures an image of the surface of the medium 90 facing the print head unit 20. The camera 30 only needs to be able to capture an image of at least a portion of the surface of the medium 90. In this embodiment, the camera 30 captures an image of a portion of the surface of the medium 90 that has been set in the printing device 1 for printing before printing is performed. More specifically, as shown in FIG. 2 , the camera 30 is mounted on the carriage 41 together with the print head unit 20, and the camera 30 moves to a predetermined position by the movement of the carriage 41 before printing based on print data is performed, and captures an image of the medium 90 that has been set on the platen 54 of the printing device 1.

[0019] In this embodiment, camera 30 is mounted on carriage 41, but it does not necessarily have to be mounted on carriage 41. In other words, camera 30 may be installed in any position where it can capture an image of the surface of medium 90 set in printing device 1 for printing.

[0020] The scanning unit 40 and transport unit 50 move the medium 90 relative to the head 21 under the control of the processing device 10. The scanning unit 40 is composed of a movably mounted carriage 41 and a movement mechanism for moving the carriage 41. The movement mechanism is composed of, for example, a guide shaft that guides the movement of the carriage in the X-axis direction and a motor that drives the movement of the carriage 41. The transport unit 50 is composed of a supply unit 51, a storage unit 52, a transport roller 53, a platen 54, and other components. The supply unit 51 rotatably supports a reel around which the medium 90 is wound in a roll, and feeds the medium 90 to a position facing the print head unit 20. The storage unit 52 rotatably supports a reel that takes up the medium 90, and takes up the medium 90 after printing is complete. The transport roller 53 includes a drive roller that moves the medium 90 in the transport direction on the top surface of the platen 54, and a driven roller that rotates as the medium 90 moves. The platen 54 is disposed opposite the print head unit 20 and supports the medium 90 being transported.

[0021] Next, the processing device 10 will be described with reference to Fig. 3. The processing device 10 has a processor 100, a memory 150, and a communication interface 160, and has the functionality of a computer.

[0022] The memory 150 is configured, for example, by a combination of volatile memory and non-volatile memory. The memory 150 is used to store programs executed by the processor 100, data used for various processes, etc. The communication interface 160 is an interface used for communication with any other device. Note that if communication with other devices is not performed, the processing device 10 does not need to include the communication interface 160.

[0023] The processor 100 reads and executes a program from the memory 150. As a result, the processor 100 realizes the functions of a print control unit 110, a captured image acquisition unit 120, an input reception unit 130, and a comparison unit 140, which will be described later. The processor 100 may be, for example, a microprocessor, an MPU (Micro Processor Unit), or a CPU (Central Processing Unit). The processor 100 may include multiple processors.

[0024] The print control unit 110 executes processing to control printing based on image data. The print control unit 110 first performs rendering processing on the image data input to the processor 100, converting each pixel of the image data into RGB data. Here, R represents red, G represents green, and B represents blue. Once the RGB data is generated, the print control unit 110 converts the RGB data for each pixel into CMYK data by referencing a first lookup table. Here, C represents cyan, M represents magenta, Y represents yellow, and K represents black. The CMYK data is ink volume data (data on density gradation values) for each color. The first lookup table associates colors formed by combinations of R, G, and B with ink volume data for each ink. Once the ink volume data is generated, the print control unit 110 performs dot resolution processing to convert the ink volume data into dot ratio data indicating the usage ratio for each ink dot size based on a second lookup table. Here, four ink dot sizes are used: Null (blank dot), S (small dot), M (medium dot), and L (large dot). The second lookup table defines the usage ratio of each ink dot size relative to the density gradation value (ink volume). The dot decomposition process converts the density gradation value into the occurrence rate of four dot types: Null (blank dot), S (small dot), M (medium dot), and L (large dot). Next, the print control unit 110 generates print data from the dot ratio data. The print data is a group of commands that cause ink to be ejected from each nozzle of the print head unit 20, and is data that specifies the nozzles to be driven and the dot size of the ink ejected from those nozzles. Specifically, to generate the print data, the print control unit 110 performs halftone processing, which determines whether or not to generate a dot in a pixel for each dot size, based on the dot ratio data of the ink dots obtained by the dot decomposition process. More specifically, the print control unit 110 uses a dither method, an error diffusion method, or the like to distribute dots of each size based on dot ratio data, thereby representing a multi-tone image (ink amount data) by a dot distribution.As a result, the print control unit 110 generates print data that is dot data that specifies one of four types of ink dots, including blank dots, for each pixel position. That is, print data that specifies one of a number of ink dots of different sizes, including blank dots, for each nozzle of each head of the print head unit 20 is generated. In this way, the print control unit 110 generates print data that drives the nozzles of each head of the print head unit 20 based on the image data. Note that the print data may also include commands for controlling the transport of the medium 90 and commands for controlling the scanning of the print head unit 20.

[0025] After the print data is generated, the print control unit 110 controls the print head unit 20, the scanning unit 40, and the transport unit 50 to print an image on the medium 90. In particular, the print control unit 110 controls the ejection of liquid (ink) from the print head unit 20 based on the print data in order to print an image represented by the image data on the medium 90.

[0026] Incidentally, when the medium 90 is a fabric, it is preferable to perform printing according to the characteristics of the medium 90. When ink is ejected onto the fabric, the ink that lands on the fabric spreads along fibers such as warp threads or weft threads. There are various types of fabrics depending on the weaving method. For example, FIG. 4 is a schematic diagram showing the warp threads and weft threads of a plain weave fabric. FIG. 5 is a schematic diagram showing the warp threads and weft threads of a satin weave fabric. As shown in FIG. 4, in a plain weave, the proportion of warp threads 91 and weft threads 92 per unit area on the surface of the fabric is the same. That is, the areas of the warp threads 91 and weft threads 92 exposed on the surface of the fabric are the same. In contrast, as shown in FIG. 5, in a satin weave, the proportion of the warp threads 91 per unit area on the surface of the fabric is larger than the proportion of the weft threads 92. That is, the area of ​​the warp threads 91 exposed on the surface of the fabric is larger than the area of ​​the weft threads 92. As described above, depending on the weaving method, the exposed warp and weft threads of a fabric may be uneven. Therefore, the extent of ink coloring that spreads along the fibers varies depending on the weaving method of the fabric. For example, when printing is performed on a satin-woven fabric in which the exposed warp threads 91 are greater than the exposed weft threads 92, the coloring is less likely to spread in the direction of the weft threads 92, but the coloring is more likely to spread in the direction of the warp threads 91. Therefore, even if ink dots are not ejected continuously in the direction of the warp threads 91, it is easy to obtain continuous coloring in the direction of the warp threads 91, whereas it is difficult to obtain continuous coloring in the direction of the weft threads 92 if ink dots are not ejected continuously in the direction of the weft threads 92. Generally, the distance between nozzles used to print on fabric is shorter than the thickness of the threads that make up the fabric.

[0027] In light of the above considerations regarding printing on fabric, the processing device 10 of the printing device 1 according to this embodiment limits the ejection of ink dots when printing on fabric medium 90. The configuration and processing of the processing device 10 in this regard will be further described below.

[0028] The captured image acquisition unit 120 acquires a captured image taken by the camera 30. That is, the captured image acquisition unit 120 acquires a captured image of the surface of the medium 90. More specifically, the captured image acquisition unit 120 acquires a captured image of the surface of the medium 90 taken by the camera 30 before printing is performed. Note that the captured image acquisition unit 120 may control the execution of photography by the camera 30. Furthermore, the control of the execution of photography may include control of the movement of the carriage 41 for photography by the camera 30.

[0029] The input receiving unit 130 receives input from a user. In particular, the input receiving unit 130 receives user input regarding information for identifying the weave of the medium 90. The user inputs the information for identifying the weave of the medium 90 to the printing device 1 via an input device such as a keyboard or a pointing device. The input device may be provided by the printing device 1 or by another device communicatively connected to the printing device 1. The information for identifying the weave of the medium 90 is any information that can identify how the warp and weft threads are woven to form the medium 90. Therefore, the information for identifying the weave of the medium 90 may be information that indicates the weave of the medium 90 itself. If the printing device 1 stores information that associates identification information of the medium 90 with information indicating the weave of the medium 90 identified by the identification information, the information for identifying the weave of the medium 90 may be the identification information of the medium 90.

[0030] The comparison unit 140 compares the size of the area occupied by the warp threads and the weft threads per unit area on the surface of the medium 90 onto which the ink is ejected. More specifically, in this embodiment, the comparison unit 140 compares the size of the area occupied by the warp threads and the weft threads per unit area on the printing surface of the medium 90 based on either the captured image acquired by the captured image acquisition unit 120 or the information acquired by the input reception unit 130. When this comparison process is performed based on the captured image acquired by the captured image acquisition unit 120, the comparison unit 140 performs image recognition processing on the captured image to identify the area occupied per unit area for each of two types of threads with different directions (i.e., warp threads and weft threads). The comparison unit 140 then compares the two identified areas. In this way, the comparison unit may compare the size of the area occupied by the warp threads and the weft threads per unit area based on the captured image. Furthermore, when the comparison process by the comparison unit 140 is performed based on information acquired by the input receiving unit 130, the comparison unit 140 determines the area ratio of two types of threads (i.e., warp and weft) with different directions from the weave identified from the acquired information. As shown in FIG. 4 or 5, once the weave of the medium 90 is identified, it is possible to determine the area ratio of the warp and weft threads per unit area. In this way, the comparison unit 140 may compare the size of the range of the warp and weft threads per unit area based on the information acquired by the input receiving unit 130.

[0031] In this embodiment, the comparison unit 140 is capable of both comparison processing using the captured images acquired by the captured image acquisition unit 120 and comparison processing using information acquired by the input acceptance unit 130, but may be capable of only one of them. Therefore, the processing device 10 does not need to include either the captured image acquisition unit 120 or the input acceptance unit 130. Furthermore, if comparison processing using the captured images acquired by the captured image acquisition unit 120 is not performed, the printing device 1 does not need to include the camera 30. Note that if comparison processing using the captured images acquired by the captured image acquisition unit 120 is performed, the information necessary for the comparison processing is automatically acquired, improving user convenience. Furthermore, if comparison processing is performed using the information acquired by the input acceptance unit 130, not only does the printing device 1 not need to include the camera 30, but the image recognition processing for the captured images is omitted, thereby simplifying the configuration of the printing device 1.

[0032] In this embodiment, the print control unit 110 controls printing based on image data in accordance with the comparison result of the comparison unit 140. Specifically, when the area per unit area of ​​one of the warp and weft threads is larger than the area per unit area of ​​the other thread, the print control unit 110 controls printing so that the amount of ink dots aligned in the direction of the one thread is reduced compared to when this is not the case. In other words, when the area per unit area of ​​one thread is larger than the area per unit area of ​​the other thread, the print control unit 110 controls printing so that the amount of ink dots aligned in the direction of the one thread is reduced compared to when there is no difference between the area of ​​the two threads. Note that when the area ratios of the warp and weft threads in a fabric are different, the area of ​​the warp threads is generally larger than the area of ​​the weft threads. Therefore, in this embodiment, in which the medium 90 is set in the printing device 1 so that the direction of the warp threads is aligned with the arrangement direction of the nozzle array, depending on the type of fabric of the medium 90, the area of ​​the threads in the transport direction (Y-axis direction) may be larger than the area of ​​the threads in the scanning direction (X-axis direction).

[0033] FIG. 6 is a flowchart showing an example of the process flow for print control in response to the comparison results of the comparison unit 140. In the example shown in FIG. 6, the print control unit 110 modifies the print data generated from image data in response to the comparison results of the comparison unit 140. According to this flowchart, when the proportion of warp threads per unit area of ​​the medium 90 is greater than the proportion of weft threads, printing is performed by restricting the use of some of the nozzles that are aligned consecutively in the warp direction. Below, a specific process flow for print control in response to the comparison results of the comparison unit 140 will be described with reference to FIG. 6.

[0034] In step S100, the camera 30 captures an image of the surface of the medium 90 set in the printing device 1. As a result, the captured image acquisition unit 120 acquires the captured image captured by the camera 30.

[0035] Next, in step S101, the comparison unit 140 determines the size H of the warp thread range and the size W of the weft thread range per unit area on the printing surface of the medium 90 from the captured image acquired in step S100. The comparison unit 140 also calculates the ratio (H / W) of the warp thread range size H to the weft thread range size W as an index for comparing the warp thread range size H and the weft thread range size W. Note that calculation of this ratio may be performed in step S104, which will be described later. In the flowchart shown in FIG. 6, the comparison unit 140 uses the captured image acquired by the captured image acquisition unit 120. However, as described above, the comparison unit 140 may calculate the ratio (H / W) of the warp thread range size H to the weft thread range size W using information acquired by the input reception unit 130 instead of the captured image acquired by the captured image acquisition unit 120.

[0036] Next, in step S102, the print control unit 110 sets the value of parameter n, which is used to specify a nozzle in the print head unit 20, to 1. The parameter n specifies one of the N nozzles that make up the nozzle row. When the value of n is 1, the nozzle at one end of the nozzle row is specified, and as the value of n increases, nozzles are specified in order from one end of the nozzle row.

[0037] Next, in step S103, the print control unit 110 determines whether the current value of n is greater than the number N of nozzles provided in each head of the print head unit 20. If the value of n is less than or equal to N (NO in step S103), the process proceeds to step S104. On the other hand, if the value of n is greater than N (YES in step S103), the process of this flowchart ends.

[0038] When the process proceeds to step S104, the print control unit 110 performs a process to determine whether or not to restrict the ejection of liquid (ink) from the nozzle specified by the value of n. Specifically, as an example, the print control unit 110 determines whether or not the value of Mod(n, ROUNDUP(H / W)) is 1. That is, in this example, if the value of this Mod function is 1 (YES in step S104), the nozzle specified by the value of n is a nozzle for which ejection is to be restricted. Therefore, in this case, the process proceeds to step S105. On the other hand, if the value of the Mod function is not 1 (NO in step S104), the nozzle specified by the value of n is not restricted from ejecting. Therefore, in this case, the process skips step S105 and proceeds to step S106. Note that Mod(x, y) is a function that calculates the remainder when x is divided by y. Furthermore, ROUNDUP(x) is a function that rounds up the decimal point to make the value of x an integer. As can be seen from the Mod function formula described above, in this example, when the size H of the warp range is larger than the size W of the weft range, ejection is restricted for nozzles selected at intervals from the N nozzles that make up the nozzle row arranged in the warp direction.

[0039] In step S105, the print control unit 110 modifies the print data generated from the image data to restrict the ejection of liquid (ink) from the nozzle specified by the value of n, i.e., the nth nozzle that makes up the nozzle row. In this embodiment, specifically, the print control unit 110 deletes the print data that controls the ejection from the nth nozzle in the print data for head 21K, head 21C, head 21M, and head 21Y. As a result, the liquid dot corresponding to this nth nozzle is forcibly made a blank dot. In other words, the ejection of liquid dots from this nth nozzle is disabled.

[0040] After step S105, the process proceeds to step S106. In step S106, the print control unit 110 increments the value of the parameter n by 1. Thereafter, the process returns to step S103, and the above-described process is repeated.

[0041] FIG. 7 is a schematic diagram illustrating a printing example in which ejection from nozzles is restricted. As an example, FIG. 7 schematically illustrates a group of dots 80 formed on a medium 90 by a head 21K having N nozzles 22K. Note that FIG. 7 illustrates an example in which ROUNDUP(H / W)=3. In the group of dots 80 illustrated in FIG. 7, the hatched dots are dots that were actually ejected onto the medium 90. In contrast, the non-hatched dots are dots that were not ejected onto the medium 90 due to the processing of the flowchart described above. The processing of the flowchart described above restricts the ejection of liquid dots ejected from nozzles aligned in the warp direction (Y-axis direction). Note that the medium 90 on which the ejection control as shown in FIG. 7 is performed is a woven fabric with many exposed warp threads, as shown in FIG. 5, and therefore, even if the ejection from some nozzles in the warp direction (Y-axis direction) is restricted, the ink spreads in the warp direction, resulting in the medium 90 being colored without interruption in the warp direction.

[0042] In this way, when the exposed yarn in the first direction is greater than the exposed yarn in the second direction, the print control unit 110 controls printing to reduce the number of dots aligned in the first direction. That is, the print control unit 110 controls printing to omit some dots by thinning out the dots. Specifically, the print control unit 110 may replace print data instructing the nozzles to eject dots with print data instructing them not to eject dots for the nozzles to be restricted. Note that, although the print control unit 110 controlled printing to reduce the number of dots in this embodiment, it may also control printing to reduce the dot size. That is, when the exposed yarn in the first direction is greater than the exposed yarn in the second direction, the print control unit 110 may change the dot size indicated in the print data generated from the image data for some of the nozzles constituting the nozzle row to a size smaller than the original size.

[0043] The printing device 1 according to the embodiment has been described above. As described above, the printing device 1 controls printing based on image data to reduce the amount of ink dots aligned in the first direction when the range of a first thread in the first direction is greater than the range of a second thread in the second direction. This reduces ink consumption. However, even with this control, the ink ejected onto the medium extends in the first direction, allowing the medium to be colored with the ink without interruption in the first direction. In other words, an image of sufficient image quality can be formed on the medium while reducing ink consumption. Furthermore, when printing on a medium made of synthetic fibers such as polyester, ink is more likely to bleed than on a medium made of natural fibers, which can absorb moisture. While reducing the amount of liquid ejected is effective in reducing bleed, this approach can result in insufficient color development. However, with the printing device 1, some dots in a row of dots in a direction where the ink spreads easily are selected as targets for ink ejection restriction. Therefore, even when ink ejection is restricted, ink spread is expected and the impact on color development is reduced. In other words, it is possible to suppress bleeding and achieve sufficient color development at the same time. In this way, the printing device 1 can provide a printing technique suitable for printing on a fabric woven with a first yarn and a second yarn.

[0044] (Variation 1) As described above, ink bleeding is likely to occur with synthetic fibers. Therefore, when the medium 90 is a synthetic fiber medium, the print control unit 110 may increase the degree of reduction in the amount of liquid dots aligned in the first direction when the range of the first thread per unit area is larger than the range of the second thread compared to when the medium 90 is not a synthetic fiber medium. The term "synthetic fiber medium" refers specifically to a case where the warp and weft threads are synthetic fiber threads. The term "non-synthetic fiber medium" refers specifically to a case where the warp and weft threads are natural fiber threads. For example, when the medium 90 is not a synthetic fiber medium, step S104 determines whether the value of Mod(n, ROUNDUP(H / W)) is 1. When the medium 90 is a synthetic fiber medium, step S104 determines whether the value of Mod(n, ROUNDUP(H / W)) is 1 or 2. If the medium 90 is a synthetic fiber medium, the print control unit 110 executes the process of step S105 if the value of Mod(n, ROUNDUP(H / W)) is either 1 or 2. In this way, when the medium 90 is a synthetic fiber medium, ejection may be restricted from more nozzles than when the medium 90 is not a synthetic fiber medium. This configuration makes it possible to suppress ink bleeding when printing on a synthetic fiber medium.

[0045] Whether or not the medium 90 is a synthetic fiber medium may be determined based on input from the user regarding the material of the medium, or may be determined by image recognition processing of the image captured by the camera 30. In other words, whether or not the medium 90 is a synthetic fiber medium may be determined based on input information received by the input receiving unit 130, or may be determined based on the captured image acquired by the captured image acquisition unit 120.

[0046] (Variation 2) Furthermore, the appropriate degree to which the liquid ejection from the nozzles should be restricted depends on the type of medium 90 or the type of liquid used. Therefore, the degree of reduction in the amount of liquid dots ejected in the first direction, which is performed when the range of the first thread is larger than the range of the second thread, may be determined based on the results of printing a test pattern on the medium 90 to be printed. Specifically, the following processing may be performed. When the range of the first thread per unit area is larger than the range of the second thread, the print control unit 110 controls the printing of multiple test patterns on the medium 90, each with a different amount of liquid dots ejected in the first direction. For example, the print control unit 110 creates various print data with different degrees of reduction for print data generated based on image data of a predetermined test pattern (e.g., a solid image), and prints various test patterns on the medium 90 according to these print data. Note that various print data with different degrees of reduction can be obtained, for example, by changing the number of candidate values ​​that Mod(n, ROUNDUP(H / W)) must satisfy in order to proceed to step S105, as described above. In this case, the test pattern is printed by changing the number of nozzles whose ejection is restricted. The print control unit 110 then determines the degree of ejection volume reduction to be applied when printing an image other than the test pattern on the medium 90, based on the print results of the multiple test patterns. The print control unit 110 may determine the degree of ejection volume reduction to be applied when printing an image desired by the user on the medium 90, for example, based on an input specifying the degree of reduction from a user who has confirmed the print results of the multiple test patterns. The print control unit 110 may also determine the degree of ejection volume reduction by performing image recognition processing on scanned images of the multiple printed test patterns and evaluating the print results. By determining the degree of ejection volume reduction based on the print results of the test patterns in this way, more appropriate printing can be achieved depending on the medium 90 and the type of ink.

[0047] The present invention is not limited to the above-described embodiment and its variations, and can be modified as appropriate without departing from the spirit of the present invention. For example, in the above-described embodiment, the processing device 10 of the printing device 1 has a print control unit 110, but some or all of the functions of the print control unit 110 may be realized by another device (computer) connected to the printing device 1. In this case, the printing device 1 and the other device may be collectively referred to as the printing device.

[0048] Also, in this disclosure, a program includes a set of instructions (or software code) that, when loaded into a computer, causes the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disk (DVD), Blu-ray (registered trademark) disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0049] Some or all of the above-described embodiments and modified examples can be described as, but are not limited to, the following supplementary notes. (Appendix 1) A printing device that performs printing by ejecting a liquid onto a medium that is a fabric woven using first yarns in a first direction and second yarns in a second direction that intersects with the first direction, a comparison unit that compares the size of the area occupied by the first yarn and the second yarn per unit area on the surface of the medium onto which the liquid is ejected; a print control unit that controls printing based on image data; and When the range of the first thread occupying per unit area is larger than the range of the second thread, the print control unit controls printing based on the image data so that the ejection amount of the liquid dots aligned in the first direction is reduced compared to when the range of the first thread occupying per unit area is not larger than the range of the second thread. Printing device. (Appendix 2) a captured image acquisition unit that acquires a captured image of the surface of the medium; The comparison unit compares the size of the range of the first yarn and the size of the range of the second yarn per unit area based on the captured image. 10. The printing device of claim 1. (Appendix 3) further comprising an input receiving unit that receives input from a user regarding information for identifying the weave of the medium; The comparison unit compares the size of the range of the first yarn and the size of the range of the second yarn per unit area based on the information. 3. The printing device of claim 1 or 2. (Appendix 4) When the range of the first thread per unit area is larger than the range of the second thread, the print control unit controls printing based on the image data so as to reduce the number of dots aligned in the first direction compared to when the range of the first thread per unit area is not larger than the range of the second thread. 4. A printing device according to any one of claims 1 to 3. (Appendix 5) When the medium is a synthetic fiber medium, the print control unit increases the degree of reduction in the ejection amount of the liquid dots aligned in the first direction when the range of the first threads per unit area is larger than the range of the second threads, compared to when the medium is not a synthetic fiber medium. 5. A printing device according to any one of claims 1 to 4. (Appendix 6) The print control unit When the range of the first thread per unit area is larger than the range of the second thread, control is performed to print on the medium a plurality of test patterns in which the ejection amounts of the liquid dots arranged in the first direction are different, based on image data of the test patterns; A degree of reduction in the ejection amount of the liquid dots aligned in the first direction, which is applied when printing an image other than the test pattern on the medium, is determined according to the printing results of the plurality of test patterns. 6. A printing device according to any one of claims 1 to 5. (Appendix 7) A printing method for printing by ejecting a liquid onto a medium that is a fabric woven using first yarns in a first direction and second yarns in a second direction that intersects with the first direction, comprising: comparing the size of the area occupied by the first yarn and the second yarn per unit area on the surface of the medium onto which the liquid is ejected; Controlling printing based on image data; In the control of the printing, when the range of the first thread occupying per unit area is larger than the range of the second thread, the printing based on the image data is controlled so that the ejection amount of the liquid dots aligned in the first direction is reduced compared to when the range of the first thread occupying per unit area is not larger than the range of the second thread. Printing method. [Explanation of symbols]

[0050] 1...printing device, 10...processing device, 20...print head unit, 21C...head, 21K...head, 21M...head, 21Y...head, 22C...nozzle, 22K...nozzle, 22M...nozzle, 22Y...nozzle, 30...camera, 40...scanning unit, 41...carriage, 50...conveying unit, 51...supply unit, 52...storing unit, 53...conveying roller, 54...platen, 80...dot group, 90...medium, 91...warp thread, 92...weft thread, 100...processor, 110...printing control unit, 120...captured image acquisition unit, 130...input receiving unit, 140...comparison unit, 150...memory, 160...communication interface

Claims

1. A printing device that performs printing by ejecting a liquid onto a medium that is a fabric woven using first yarns in a first direction and second yarns in a second direction that intersects with the first direction, a comparison unit that compares the size of the area occupied by the first yarn and the second yarn per unit area on the surface of the medium onto which the liquid is ejected; a print control unit that controls printing based on image data; and When the range of the first thread occupying per unit area is larger than the range of the second thread, the print control unit controls printing based on the image data so that the ejection amount of the liquid dots aligned in the first direction is reduced compared to when the range of the first thread occupying per unit area is not larger than the range of the second thread. Printing device.

2. a captured image acquisition unit that acquires a captured image of the surface of the medium; The comparison unit compares the size of the range of the first yarn and the size of the range of the second yarn per unit area based on the captured image. The printing device of claim 1 .

3. further comprising an input receiving unit that receives input from a user regarding information for identifying the weave of the medium; The comparison unit compares the size of the range of the first yarn and the size of the range of the second yarn per unit area based on the information.

3. The printing device according to claim 1 or 2.

4. When the range of the first thread occupying per unit area is larger than the range of the second thread, the print control unit controls printing based on the image data so as to reduce the number of dots aligned in the first direction compared to when the range of the first thread occupying per unit area is not larger than the range of the second thread. The printing device of claim 1 .

5. When the medium is a synthetic fiber medium, the print control unit increases the degree of reduction in the ejection amount of the liquid dots aligned in the first direction when the range of the first threads per unit area is larger than the range of the second threads, compared to when the medium is not a synthetic fiber medium. The printing device of claim 1 .

6. The print control unit When the range of the first thread per unit area is larger than the range of the second thread, control is performed to print a plurality of test patterns on the medium, each test pattern having different ejection amounts of the liquid dots arranged in the first direction, based on image data of the test patterns; A degree of reduction in the ejection amount of the liquid dots aligned in the first direction, which is applied when printing an image other than the test pattern on the medium, is determined according to the printing results of the plurality of test patterns. The printing device of claim 1 .

7. A printing method for printing by ejecting a liquid onto a medium that is a fabric woven using first yarns in a first direction and second yarns in a second direction that intersects with the first direction, the method comprising: comparing the size of the area occupied by the first yarn and the second yarn per unit area on the surface of the medium onto which the liquid is ejected; Controlling printing based on image data; In the control of the printing, when the range of the first thread occupying per unit area is larger than the range of the second thread, the printing based on the image data is controlled so that the ejection amount of the liquid dots aligned in the first direction is reduced compared to when the range of the first thread occupying per unit area is not larger than the range of the second thread. Printing method.

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