Discharge quantity upper limit determination method and printing device

Abstract

To provide a technique that can determine a discharge quantity upper limit at which excessive reduction in chromogenic property or excessive bleeding of liquid can be suppressed even if bleeding of liquid varies widely.SOLUTION: In a test pattern forming step, a test pattern is formed on a medium, the test pattern including a plurality of pattern rows including a plurality of patches (including a bleeding detection region and a background region) having different discharge quantities per unit area at which liquid is permitted to bleed. In an upper limit determining step, a provisional discharge quantity upper limit as a provisional value of an upper limit of the discharge quantities is determined based on results of reading the plurality of patches included in each of the pattern rows. When a difference between a maximum value and a minimum value of the plurality of provisional discharge quantity upper limits obtained for to the plurality of pattern rows is within an allowable range, either of the minimum value and the maximum value is determined as the upper limit. When the difference is above the allowable range, the upper limit is determined so that it is larger than the minimum value and smaller than the maximum value.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a technique for determining an upper limit of the ejection amount per unit area of ​​a liquid ejected from a print head onto a medium, at which bleeding of the liquid is permitted. [Background technology]

[0002] As a printing device, an inkjet printer that ejects ink droplets of multiple colors onto a printing medium from multiple nozzles of a print head is known. When the amount of ink ejected per unit area onto a printing medium is large, a phenomenon called "bleeding" may occur. Here, bleeding is a phenomenon in which ink seeps out to the surroundings. The degree of bleeding may vary depending on the type of printing medium and the type of ink. Therefore, by using a test pattern including multiple pattern rows including multiple patches with different ink ejection amounts to detect the degree of bleeding, an ink ejection amount upper limit value indicating the upper limit of the ink ejection amount at which bleeding can be suppressed is set, and is used for creating a color conversion LUT (lookup table), etc. The printing device disclosed in Patent Document 1 performs a process of determining the above-mentioned ink ejection amount upper limit value so that phenomena other than "bleeding" can also be suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-126993 A Summary of the Invention [Problem to be solved by the invention]

[0004] The degree of bleeding in each patch may vary greatly depending on the type of printing medium, etc. When the variation in bleeding is large, if the upper discharge amount limit is determined based on the ink discharge amount of a patch included in a pattern row with the greatest degree of bleeding, the color gamut that the inkjet printer can express will be narrowed. When the color gamut is narrowed, the color development of the printed image will be significantly reduced, and the image quality of the printed image will be reduced. Furthermore, when the variation in bleeding is large, if the upper discharge amount limit is determined based on the ink discharge amount of a patch included in a pattern row with the least degree of bleeding, the degree of bleeding may become too large. When the degree of bleeding becomes too large, the image quality of the printed image will be reduced. [Means for solving the problem]

[0005] The method for determining an upper limit of a discharge amount of a liquid discharged from a print head onto a medium is a method for determining an upper limit of a discharge amount of the liquid per unit area at which bleeding of the liquid is permitted, the method comprising the steps of: The liquid is of a plurality of different colors, a test pattern forming step of forming, on the medium, a test pattern including a pattern array including a plurality of patches having different ejection amounts, each of the patches including a bleeding detection region and a background region having a color different from that of the bleeding detection region; an upper limit value determination step of acquiring the read results of the plurality of patches included in the plurality of pattern sequences, and determining the upper limit value based on the read results of the plurality of patches, In the upper limit determination step, determining a provisional upper limit value of the upper limit for each of the pattern rows based on the reading results of the plurality of patches included in the pattern row; determining, when a difference between a maximum value of the plurality of provisional discharge amount upper limit values ​​obtained for the plurality of pattern sequences and a minimum value of the plurality of provisional discharge amount upper limit values ​​is within an allowable range, one of the minimum value and the maximum value as the upper limit value; If the difference exceeds the allowable range, the upper limit is determined to be greater than the minimum value and less than the maximum value. It has an aspect.

[0006] The printing device of the present invention further comprises: A print head that ejects a plurality of different colored liquids onto a medium; a control unit that performs control to form, on the medium, a test pattern including a pattern array including a plurality of patches each having a different ejection amount per unit area for which bleeding of the liquid is permitted, the pattern array including a bleeding detection region and a background region of a color different from that of the bleeding detection region, acquires reading results of the plurality of patches included in the plurality of pattern arrays, and performs processing to determine an upper limit value of the ejection amount based on the reading results of the plurality of patches; A reading unit that reads the plurality of patches, The control unit is a first process for determining a provisional upper limit value of the ejection amount, which is a provisional value of the upper limit value, for each of the pattern arrays based on a reading result of the plurality of patches included in the pattern array; a second process of determining, when a difference between a maximum value of the plurality of provisional discharge amount upper limit values ​​obtained for the plurality of pattern sequences and a minimum value of the plurality of provisional discharge amount upper limit values ​​is within an allowable range, one of the minimum value and the maximum value as the upper limit value; and if the difference exceeds the allowable range, a third process is performed to determine the upper limit value so as to be greater than the minimum value and less than the maximum value. It has an aspect. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram illustrating a schematic configuration example of a printing apparatus. [Diagram 2] FIG. 4 is a diagram illustrating an example of the operation of the printer. [Diagram 3] FIG. 10 is a diagram illustrating an example of a test pattern on a medium. [Figure 4] FIG. 4 is a diagram showing an example of ink ejection amount. [Diagram 5] 11A and 11B are diagrams illustrating examples of bleeding that occurs in a patch having a line region for detecting the amount of bleeding. [Figure 6]FIG. 13 is a diagram illustrating an example of determining the discharge amount upper limit Dt_final when the variation in the bleeding amount V1 is small. [Figure 7] FIG. 13 is a diagram illustrating an example of determining the discharge amount upper limit Dt_final when the variation in the bleeding amount V1 is large. [Figure 8] 10 is a flowchart showing an example of an ink ejection amount upper limit value determination process. [Figure 9] 6 is a flowchart illustrating an example of a printing process. [Figure 10] FIG. 4 is a diagram illustrating a display example of a UI screen. [Figure 11] FIG. 13 is a diagram illustrating an example in which a change in a determination threshold value is accepted in accordance with an upper limit value of a discharge amount. [Figure 12] 10 is a flowchart showing an example of an ink ejection amount upper limit determination process for determining an ejection amount upper limit for each individual color. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments of the present invention will be described. Of course, the following embodiments are merely illustrative of the present invention, and not all of the features shown in the embodiments are necessarily essential to the solution of the invention.

[0009] (1) Overview of the technology included in this invention: First, the outline of the technology included in the present invention will be described with reference to the examples shown in Figures 1 to 12. The figures in this application are diagrams showing examples in a schematic manner, and the magnification in each direction shown in these figures may differ, and the figures may not be consistent with each other. Of course, each element of the present technology is not limited to the specific example indicated by the symbol. In the "outline of the technology included in the present invention," the words in parentheses indicate supplementary explanations of the immediately preceding words. In addition, in the present application, a numerical range "Min to Max" means equal to or greater than the minimum value Min and equal to or less than the maximum value Max.

[0010] [Aspect 1] 1, 8, etc., a method for determining an upper limit value of a discharge amount per unit area for determining an upper limit value Dt_final of a discharge amount per unit area at which bleeding of a liquid (e.g., ink 236) discharged from a print head 230 onto a medium ME0 is permitted for the liquid (236), and includes the following steps: Here, the liquid (236) is of multiple types with different colors (e.g., cyan, magenta, yellow, and black). (a1) A test pattern forming process ST1 is performed to form a test pattern 500 on the medium ME0, the test pattern 500 including a pattern array P0 including a plurality of patches 510 having different ejection amounts, each of the patches 510 including a bleeding detection area (e.g., a line area 532) and a background area (e.g., a solid area 531) of a color different from the bleeding detection area (532). (a2) An upper limit determination step ST2 of acquiring the read results (e.g., image information 322) of the plurality of patches 510 included in the plurality of pattern sequences P0, and determining the upper limit value Dt_final based on the read results (322) of the plurality of patches 510. The upper limit determining step ST2 includes the following steps. (b1) A process (eg, steps S106 to S110) of determining a provisional upper limit value Dt_p of the discharge amount, which is a provisional value of the upper limit value Dt_final, for each of the pattern sequences P0 based on the read results (322) of the plurality of patches 510 included in the pattern sequence P0. (b2) When the difference Dt_pdif between the maximum value Dt_pmax of the multiple provisional discharge volume upper limit values ​​Dt_p obtained for the multiple pattern series P0 and the minimum value Dt_pmin of the multiple provisional discharge volume upper limit values ​​Dt_p is within an acceptable range (e.g., a threshold value TH_Duty), a process of determining one of the minimum value Dt_pmin and the maximum value Dt_pmax as the upper limit value Dt_final (e.g., step S116). (b3) When the difference Dt_pdif exceeds the allowable range (TH_Duty), determining the upper limit Dt_final so that it is greater than the minimum value Dt_pmin and smaller than the maximum value Dt_pmax (for example, step S118).

[0011] When the difference Dt_pdif between the maximum value Dt_pmax of the provisional discharge amount upper limit value Dt_p and the minimum value Dt_pmin of the provisional discharge amount upper limit value Dt_p is within the allowable range (TH_Duty), the variation in bleeding is small, and one of the minimum value Dt_pmin and the maximum value Dt_pmax is determined as the discharge amount upper limit value Dt_final. Note that "variation in bleeding" refers to the variation in the degree of bleeding in the bleeding detection areas of the multiple patches 510 used to determine the upper limit value Dt_final. For example, when the upper limit value Dt_final is divided for each order of color, "variation in bleeding" refers to the variation in the degree of bleeding detected for each order. When the difference Dt_pdif between the maximum value Dt_pmax and the minimum value Dt_pmin exceeds the allowable range (TH_Duty), the variation in bleeding is large, and the discharge amount upper limit Dt_final is determined to be greater than the minimum value Dt_pmin and smaller than the maximum value Dt_pmax. The discharge amount upper limit Dt_final is greater than the minimum value Dt_pmin of the provisional discharge amount upper limit Dt_p, so that the color development of the printed image IM0 is prevented from decreasing too much. The discharge amount upper limit Dt_final is smaller than the maximum value Dt_pmax of the provisional discharge amount upper limit Dt_p, so that the liquid (236) is prevented from bleeding too much. Therefore, the above aspect can provide a discharge amount upper limit determination method that can determine a discharge amount upper limit that prevents the color development from decreasing too much or the liquid from bleeding too much even if the variation in bleeding is large. Furthermore, if the difference Dt_pdif between the maximum value Dt_pmax of the provisional discharge volume upper limit value Dt_p and the minimum value Dt_pmin of the provisional discharge volume upper limit value Dt_p is within the allowable range (TH_Duty), it is only necessary to set the minimum value Dt_pmin or the maximum value Dt_pmax to the discharge volume upper limit value Dt_final, so less memory capacity is required for this process.

[0012] Here, the patch reading result includes the patch imaging result by an imaging unit such as a camera, the patch reading result by an image reading unit such as a scanner, and the like. If the difference exceeds the tolerance, it means that the difference is not within the tolerance. For example, a threshold is used to realize the case distinction. In this case, if being equal to or less than the threshold corresponds to being within the tolerance, then being greater than the threshold corresponds to being beyond the tolerance, and if being equal to or less than the threshold corresponds to being within the tolerance, then being equal to or more than the threshold corresponds to being beyond the tolerance. The above remarks also apply to the following aspects.

[0013] [Aspect 2] As illustrated in FIG. 8 etc., in the upper limit determination step ST2, if the difference Dt_pdif exceeds the allowable range (TH_Duty), the average value of the multiple provisional discharge amount upper limit values ​​Dt_p may be determined as the upper limit value Dt_final. In the above cases, when the variation in bleeding is large, the discharge amount upper limit Dt_final becomes as far away as possible from both the minimum value Dt_pmin and the maximum value Dt_pmax of the provisional discharge amount upper limit Dt_p. Therefore, the above embodiment can provide a suitable example for preventing excessive deterioration in color development or excessive bleeding of the liquid even when the variation in bleeding is large.

[0014] [Aspect 3] As exemplified in FIG. 3, the test pattern 500 may include an n-th color test pattern 50n in which the bleeding detection area (532) of the patch 510 is an n-th color, where n is an integer equal to or greater than 1 and less than the number of types of the liquid (236). The provisional discharge amount upper limit Dt_p may include an n-th color provisional discharge amount upper limit Dt_p(n) for the n-th color test pattern 50n. The allowable range (TH_Duty) may include an n-th color allowable range for the n-th color (e.g., a threshold value TH_Duty(n)). The upper limit determination step ST2 may include the following steps, as exemplified in FIG. 8. (c1) A process (e.g., steps S106 to S110) of determining the n-th color provisional ejection amount upper limit value Dt_p(n) for each pattern sequence P0 in the n-th color test pattern 50n based on the reading results (322) of the multiple patches 510 included in the pattern sequence P0. (c2) If the difference Dt_pdif(n) between the n-th color maximum value Dt_pmax(n), which is the maximum value of the multiple n-th color provisional discharge rate upper limit values ​​Dt_p(n), and the n-th color minimum value Dt_pmin(n), which is the minimum value of the multiple n-th color provisional discharge rate upper limit values ​​Dt_p(n), is within the n-th color tolerance range (TH_Duty(n)), a process (e.g., step S116) of determining one of the n-th color minimum value Dt_pmin(n) and the n-th color maximum value Dt_pmax(n) as the upper limit value Dt_final (e.g., Dt_final(n)) for the n-th color. (c3) If the difference Dt_pdif(n) between the nth color maximum value Dt_pmax(n) and the nth color minimum value Dt_pmin(n) exceeds the nth color tolerance range (TH_Duty(n)), a process (e.g., step S118) of determining the upper limit value (Dt_final(n)) for the nth color so that it is greater than the nth color minimum value Dt_pmin(n) and less than the nth color maximum value Dt_pmax(n).

[0015] When the difference Dt_pdif(n) between the n-th color maximum value Dt_pmax(n) and the n-th color minimum value Dt_pmin(n) is within the n-th color tolerance range (TH_Duty(n)), the variation in bleeding for the n-th color is small, and one of the n-th color minimum value Dt_pmin(n) and the n-th color maximum value Dt_pmax(n) is determined as the upper discharge amount value (Dt_final(n)) for the n-th color. When the difference Dt_pdif(n) between the n-th color maximum value Dt_pmax(n) and the n-th color minimum value Dt_pmin(n) exceeds the n-th color tolerance range (TH_Duty(n)), the variation in bleeding for the n-th color is large, and the upper discharge amount value (Dt_final(n)) for the n-th color is determined to be larger than the n-th color minimum value Dt_pmin(n) and smaller than the n-th color maximum value Dt_pmax(n). Therefore, the above aspect makes it possible to determine an upper limit value of the n-th color ejection amount that prevents the color development from decreasing too much or prevents the liquid from bleeding too much even if the bleeding of the n-th color varies greatly.

[0016] [Aspect 4] 3, the test pattern 500 may include an individual color test pattern 504 in which the bleeding detection area (532) of the patch 510 is an individual color included in a plurality of colors that are n-th order colors, where n is an integer greater than or equal to 1 and less than the number of types of the liquid (236). The provisional ejection rate upper limit Dt_p may include an individual color provisional ejection rate upper limit Dt_p(i) for the individual color test pattern 504. The allowable range (TH_Duty) may include an individual color allowable range for the individual color (e.g., a threshold value TH_Duty(i)). The upper limit determination step ST2 may include the following steps, as illustrated in FIG. 12. (d1) A process (eg, steps S306 to S310) of determining the individual color provisional upper limit value Dt_p(i) for each pattern sequence P0 in the individual color test pattern 504 based on the read results (322) of the multiple patches 510 included in the pattern sequence P0. (d2) When the difference Dt_pdif(i) between the individual color maximum value Dt_pmax(i), which is the maximum value of the multiple individual color provisional ejection rate upper limit values ​​Dt_p(i), and the individual color minimum value Dt_pmin(i), which is the minimum value of the multiple individual color provisional ejection rate upper limit values ​​Dt_p(i), is within the individual color tolerance range (TH_Duty(i)), a process (e.g., step S316) of determining one of the individual color minimum value Dt_pmin(i) and the individual color maximum value Dt_pmax(i) as the upper limit value Dt_final (e.g., Dt_final(i)) for the individual color. (d3) If the difference Dt_pdif(i) between the individual color maximum value Dt_pmax(i) and the individual color minimum value Dt_pmin(i) exceeds the individual color tolerance range (TH_Duty(i)), a process (e.g., step S318) of determining the upper limit value (Dt_final(i)) for the individual color so that it is greater than the individual color minimum value Dt_pmin(i) and less than the individual color maximum value Dt_pmax(i).

[0017] When the difference Dt_pdif(i) between the individual color maximum value Dt_pmax(i) and the individual color minimum value Dt_pmin(i) is within the individual color tolerance range (TH_Duty(i)), the variation in bleeding for the individual color is small, and one of the individual color minimum value Dt_pmin(i) and the individual color maximum value Dt_pmax(i) is determined as the discharge amount upper limit value (Dt_final(i)) for the individual color. When the difference Dt_pdif(i) between the individual color maximum value Dt_pmax(i) and the individual color minimum value Dt_pmin(i) exceeds the individual color tolerance range (TH_Duty(i)), the variation in bleeding for the individual color is large, and the discharge amount upper limit value (Dt_final(i)) for the individual color is determined to be larger than the individual color minimum value Dt_pmin(i) and smaller than the individual color maximum value Dt_pmax(i). Therefore, the above aspect makes it possible to determine the upper limit of the individual color ejection amount, which prevents the color development from decreasing too much and prevents the liquid from bleeding too much, even if the bleeding of the individual colors varies greatly. Here, the terms "first", "second", ... in this application are terms for distinguishing between components among a plurality of components having similarities, and do not indicate order. This statement also applies to the following aspects.

[0018] [Aspect 5] As illustrated in FIG. 8 and other figures, the method for determining the upper limit of the discharge amount may further include the following steps. (a3) A tolerance update receiving step ST3 of receiving an operation to update the tolerance (TH_Duty) and updating the tolerance (TH_Duty) in response to the operation. In the above cases, the user can update the allowable range of bleeding variation (TH_Duty) according to preference. Therefore, the above aspect can determine the upper limit of the ejection amount that reflects the user's preference.

[0019] [Aspect 6] 8 etc., in the upper limit value determination step ST2, for each of the pattern sequences P0, a bleeding amount V1 indicating the degree of bleeding of the bleeding detection area (532) included in each of the patches 510 may be obtained from the reading results (322) of the patches 510 included in the pattern sequence P0, and the bleeding amount V1 may be compared with a judgment threshold value TH corresponding to the upper limit of the bleeding amount V1 to determine the provisional discharge amount upper limit Dt_p. This discharge amount upper limit value determination method may further include the following steps. (a4) A determination threshold change receiving step ST4 of receiving a change to the determination threshold TH. In the above cases, the user can change the degree of bleeding that is acceptable according to preference. Therefore, the above-described embodiment can determine the upper limit of the ejection amount that reflects the user's preference.

[0020] [Aspect 7] 8, in the upper limit value determination step ST2, when the difference Dt_pdif is within the allowable range (TH_Duty), the minimum value Dt_pmin may be determined as the upper limit value Dt_final. In this embodiment, when the variation in bleeding is small, the upper limit value of the discharge amount can be determined by prioritizing the suppression of bleeding.

[0021] [Aspect 8] As illustrated in FIG. 1, the printing device 1 according to an embodiment of the present technology includes a print head 230, a control unit 110, and a reading unit (e.g., an imaging unit 261). The print head 230 ejects a liquid (236) of a plurality of different colors onto a medium ME0. The control unit 110 performs control to form a test pattern 500 including a pattern array P0 including a plurality of patches 510 having different ejection amounts per unit area that allow bleeding of the liquid (236), the pattern array P0 including each patch 510 including a bleeding detection area (532) and a background area (531) of a color different from the bleeding detection area (532), on the medium ME0, acquires reading results (322) of the plurality of patches 510 included in the plurality of pattern arrays P0, and performs processing to determine the upper limit value Dt_final of the ejection amount based on the reading results (322) of the plurality of patches 510. The reading section (261) reads at least a part of the plurality of patches 510. The control section 110 performs the following processes. (e1) A first process (eg, steps S106 to S110) for determining a provisional upper limit value Dt_p of the ejection amount, which is a provisional value of the upper limit value Dt_final, based on the read results (322) of the plurality of patches 510 included in each of the pattern sequences P0. (e2) A second process (e.g., step S116) in which, when the difference Dt_pdif between the maximum value Dt_pmax of the multiple provisional discharge volume upper limits Dt_p obtained for the multiple pattern series P0 and the minimum value Dt_pmin of the multiple provisional discharge volume upper limits Dt_p is within an allowable range (TH_Duty), one of the minimum value Dt_pmin and the maximum value Dt_pmax is determined as the upper limit value Dt_final. (e3) A third process (eg, step S118) for determining the upper limit value Dt_final so that the upper limit value Dt_final is greater than the minimum value Dt_pmin and smaller than the maximum value Dt_pmax when the difference Dt_pdif exceeds the allowable range (TH_Duty).

[0022] The above aspect can provide a printing device capable of determining an upper limit value for the ejection amount that prevents excessive deterioration in color development or excessive bleeding of the liquid even if there is a large variation in bleeding. Here, the reading unit includes an imaging unit such as a camera, an image reading unit such as a scanner, and the like. The control unit may perform the processes corresponding to the above-mentioned aspects 2 to 7.

[0023] Furthermore, the present technology is applicable to a printing method including the above-mentioned method for determining an upper limit of the discharge amount, a multifunction device including the above-mentioned printing device, a program for determining an upper limit of the discharge amount for realizing the above-mentioned method for determining an upper limit of the discharge amount in a computer, a print control program for realizing the above-mentioned printing method in a computer, a computer-readable recording medium having any of the above-mentioned programs recorded thereon, etc. Any of the above-mentioned devices may be composed of multiple distributed parts.

[0024] (2)Specific examples of printing device configuration: Fig. 1 is a schematic diagram of a configuration of a printing device. Fig. 2 is a schematic diagram of an operation of a printer. Fig. 3 is a schematic diagram of a test pattern on a medium. The printing device 1 shown in FIG. 1 is a device in a broad sense including a host device 100 and a printer 200, and can also be called a printing system. Of course, the printing device 1 may be the printer 200 alone. The host device 100 includes a CPU (Central Processing Unit) 111, which is a processor, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, a storage device 114, an input device 115, a display device 116, a communication I / F (interface) 117, and the like. The above-mentioned elements (111 to 117) are electrically connected and are capable of inputting and outputting information to and from each other. The ROM 112, the RAM 113, and the storage device 114 are memories, and at least the ROM 112 and the RAM 113 are semiconductor memories. The configuration of the printer 200 will be described later.

[0025] The storage device 114 stores an operating system (OS) (not shown), a print control program PR0, test pattern data 321 used to print the test pattern 500 shown in FIG. 3, a threshold value TH for determining the bleeding amount V1 shown in FIGS. 6 and 7, a threshold value TH_Duty for determining the variation shown in FIGS. 6 and 7, and the like. The storage device 114 also stores imaging information 322 generated by the imaging unit 261 of the printer 200, and the like. The storage device 114 may be a non-volatile semiconductor memory such as a flash memory, a magnetic storage device such as a hard disk, or the like. The input device 115 may be a pointing device, a hard key including a keyboard, a touch panel attached to the surface of a display panel, or the like. The display device 116 displays a screen corresponding to the display information based on the display information. The display device 116 may be a liquid crystal display panel, or the like. The communication I / F 117 is connected to a communication I / F 220 of the printer 200, and inputs and outputs information such as print data to and from the printer 200. The communication of the communication I / Fs 117 and 220 may be wired or wireless, or may be network communication such as a local area network (LAN) or the Internet.

[0026] The print control program PR0 causes the host device 100 to function as a test pattern forming processing unit 311, an upper limit value determining unit 312, an allowable range update receiving unit 313, a judgment threshold change receiving unit 314, and the like. The test pattern forming processing unit 311 performs control to form a test pattern 500 on a medium ME0. The upper limit value determining unit 312 acquires imaging information 322 of a plurality of patches 510 included in the test pattern 500, and determines an upper limit value Dt_final (see Figs. 6 and 7) of the ink discharge amount Duty based on the imaging information 322. The allowable range update receiving unit 313 receives an operation to update the threshold value TH_Duty as the allowable range shown in Figs. 6 and 7, and updates the threshold value TH_Duty in response to the operation. The judgment threshold change receiving unit 314 receives a change to the judgment threshold value TH corresponding to the upper limit of the bleeding amount V1 shown in Figs. 6 and 7. Details of these elements (311 to 314) will be described later. The print control program PR0 causes the host device 100 to realize a test pattern formation processing function FU1 corresponding to the test pattern formation processing unit 311, an upper limit value determination function FU2 corresponding to the upper limit value determination unit 312, an allowable range update reception function FU3 corresponding to the allowable range update reception unit 313, a determination threshold change reception function FU4 corresponding to the determination threshold change reception unit 314, and the like. The discharge amount upper limit value can be called a discharge amount limit value, and more specifically, can be called an ink duty limit value. The CPU 111 of the host device 100 reads information stored in the storage device 114 into the RAM 113 as appropriate, and executes the read program to perform various processes. The CPU 111 performs processes corresponding to the above-mentioned functions (FU1 to FU4) by executing the print control program PR0 read into the RAM 113. The CPU 111 that executes the print control program PR0 is an example of the control unit 110, and performs the steps corresponding to the above-mentioned functions (FU1 to FU4). The computer-readable recording medium that stores the print control program PR0 is not limited to a storage device inside the host device, and may be a recording medium external to the host device.

[0027] The host device 100 includes computers such as personal computers, mobile phones such as smartphones, digital cameras, digital video cameras, etc. The host device 100 may have all of its components (111-117) in one housing, or may be composed of multiple devices separated so as to be able to communicate with each other. The present technology can also be implemented if at least a part of the printer 200 is in the host device 100.

[0028] The printer 200 shown in FIGS. 1 and 2 is an inkjet printer that ejects C ink, M ink, Y ink, and K ink as ink 236 containing coloring materials from a print head 230 onto a medium ME0 to form a print image IM0 corresponding to print data. Here, the ink 236 is an example of a liquid, and the ink droplets 237 ejected from the print head 230 are an example of droplets, with C representing cyan, M representing magenta, Y representing yellow, and K representing black. Thus, the ink 236 shown in FIG. 1 has four different colors. The printer 200 includes a controller 210, the above-mentioned communication I / F 220, the print head 230, a drive unit 250, an imaging unit 261, a colorimetric unit 262, and the like. The imaging unit 261 is an example of a reading unit that reads a plurality of patches 510 included in a test pattern 500 for detecting a bleeding amount V1 (see FIGS. 6 to 8) that indicates the degree of bleeding. The controller 210 includes a processor CPU 211, a ROM 212, a RAM 213, a color conversion unit, a halftone processing unit, a drive signal transmission unit, etc., and controls the operation of the communication I / F 220, the print head 230, the drive unit 250, the image capture unit 261, the color measurement unit 262, etc. Based on print data acquired from the host device 100, the controller 210 controls the ejection of ink droplets 237 by the print head 230 and the scanning by the drive unit 250. For example, when two colors, R, G, and B, are assigned to each pixel, the controller 210 controls the ejection of ink droplets 237 by the print head 230 and the scanning by the drive unit 250. 8 It is assumed that the communication I / F 220 receives print data including RGB data having integer values ​​equal to or greater than the gradation. Here, R means red, G means green, and B means blue. The color conversion unit converts the RGB data into two colors, C, M, Y, and K, for each pixel. 8The controller 210 can be configured with a SoC (System on a Chip) or the like.

[0029] The printer 200 shown in FIG. 2 is a serial printer that performs printing while moving a carriage 252 in both directions along a first direction D1. Of course, the printer 200 may be a line printer that does not have a carriage. The carriage 252 is equipped with a print head 230, an imaging unit 261, and a color measurement unit 262. The drive unit 250 includes a carriage drive unit 251 that moves the carriage 252 in the forward direction D11 and the backward direction D12 under the control of the controller 210, and a feed unit 255 that feeds the medium ME0 in the second direction D2 under the control of the controller 210. Here, the forward direction D11 and the backward direction D12 are directions along the first direction D1, the backward direction D12 is a direction opposite to the forward direction D11, and the second direction D2 is a direction perpendicular to the first direction D1.

[0030] The print head 230 includes a drive circuit, a drive element, and the like, and performs printing by ejecting ink droplets 237 from a plurality of nozzles 234 included in a nozzle row 233 onto the medium ME0. Here, the nozzle means a small hole from which ink droplets are ejected, and the nozzle row means an arrangement of a plurality of nozzles. The drive element may be a piezoelectric element that applies pressure to ink in a pressure chamber that communicates with the nozzle 234, or a drive element that uses heat to generate air bubbles in the pressure chamber to eject ink droplets 237 from the nozzle 234. The drive signal transmission unit included in the controller 210 generates a drive signal based on the print data, for example, a drive signal according to dot data, and outputs the drive signal to the drive circuit of the print head 230. The drive signal corresponds to a voltage signal applied to the drive element of the print head 230. For example, if the binary dot data based on the print data is "dot formation", the drive signal transmission unit outputs a drive signal that ejects ink droplets for dot formation. In addition, when the dot data is four-value data, the drive signal transmission unit outputs a drive signal to eject ink droplets for large dots if the dot data is "large dot formation", outputs a drive signal to eject ink droplets for medium dots if the dot data is "medium dot formation", and outputs a drive signal to eject ink droplets for small dots if the dot data is "small dot formation".

[0031] The print head 230 shown in FIG. 2 has a plurality of nozzle rows 233 including a plurality of nozzles 234 arranged at intervals of a predetermined nozzle pitch in the second direction D2, and is arranged on a surface of the carriage 252 facing the medium ME0. The arrangement direction of the plurality of nozzles 234 included in each nozzle row 233 may be shifted from the second direction D2 as long as it intersects with the first direction D1. The plurality of nozzle rows 233 include a cyan nozzle row 23C that ejects C ink droplets 237, a magenta nozzle row 23M that ejects M ink droplets 237, a yellow nozzle row 23Y that ejects Y ink droplets 237, and a black nozzle row 23K that ejects K ink droplets 237. Each nozzle row 233 ejects ink droplets 237 toward the medium ME0. The plurality of nozzles 234 included in each nozzle row 233 may be arranged in a single row or in a staggered manner, i.e., in two rows. When the ink droplets 237 land on the medium ME0, dots DT0 (see FIG. 4) of ink 236 are formed on the medium ME0. As a result, a printed matter having a print image IM0 on the medium ME0 is obtained. The medium ME0 is not particularly limited, and includes paper, fabric, resin, metal, etc. The shape of the medium ME0 may be a roll, a cut two-dimensional shape, or a three-dimensional shape.

[0032] The imaging unit 261 includes an area sensor, captures an image of an individual patch 510, such as patches 511 to 515, included in the test pattern 500 shown in FIG. 3, and outputs imaging information 322, which is an imaging result as a reading result. The imaging unit 261 may include a line sensor instead of an area sensor. The imaging unit 261 is disposed on a surface of the carriage 252 facing the medium ME0, and captures an image when the carriage 252 moves along the first direction D1. The imaging unit 261 shown in FIG. 2 is located on the carriage 252 at a position facing the print head 230 in the second direction D2. This allows the imaging unit 261 to capture an image of a patch formed in a certain main scan in a subsequent main scan. The printer 200 transmits the imaging information 322 generated by the imaging unit 261 to the host device 100. The host device 100 may store the received imaging information 322 as is in the storage device 114, or may store updated imaging information 322 to which additional information obtained from the received imaging information 322 has been added in the storage device 114.

[0033] The color measurement unit 262 can measure the color of individual patches included in a color measurement test pattern (not shown) and output color measurement information as a color measurement result corresponding to the color of the patch. The color measurement result is different from the image pickup result by the image pickup unit 261. The color measurement information is, for example, based on the CIE (International Commission on Illumination) L * a * b * Lightness in color space L * and chromaticity coordinate a * ,b * Of course, the colorimetric information may be color values ​​in the CIE XYZ color space or the like.

[0034] As shown in Fig. 3, the test pattern 500 includes a plurality of pattern arrays P0, each of which includes a plurality of patches 510 having different ejection amounts of the ink 236. In the example shown in Fig. 3, the pattern arrays P0 are arranged in a first direction D1, and the plurality of patches 510 included in each pattern array P0, for example, patches 511 to 515, are arranged in a second direction D2. Of course, the arrangement direction of the pattern arrays and the arrangement direction of the patches in the pattern arrays are not limited to the example shown in Fig. 3, and for example, the pattern arrays may be arranged in the second direction D2, and the patches in the pattern arrays may be arranged in the first direction D1. The multiple pattern arrays P0 include multiple pattern arrays P1 for detecting the bleeding amount V1 of a primary color, multiple pattern arrays P2 for detecting the bleeding amount V1 of a secondary color, and one or more pattern arrays P3 for detecting the bleeding amount V1 of a tertiary color. A primary color is a color expressed by only one type of ink, a secondary color is a color expressed by two types of ink with different colors, and a tertiary color is a color expressed by three types of ink with different colors. The pattern arrays P11 to P15 shown in FIG. 3 are examples of the pattern array P1 for the primary color. The pattern arrays P16 to P18 shown in FIG. 3 are examples of the pattern array P2 for the secondary color. The pattern array P19 shown in FIG. 3 is an example of the pattern array P3 for the tertiary color. Thus, the test pattern 500 includes a primary color test pattern 501 including multiple pattern arrays P1, a secondary color test pattern 502 including multiple pattern arrays P2, and a tertiary color test pattern 503 including one or more pattern arrays P3. The n-th color test pattern 50n collectively refers to the primary color test pattern 501, the secondary color test pattern 502, and the tertiary color test pattern 503. In this specific example, there are four types of ink 236, and the order n is an integer equal to or greater than 1 and less than 4.

[0035] FIG. 4 is a diagram for explaining a schematic example of an ink discharge amount (referred to as Duty). In the example shown in FIG. 4, 6×6=36 pixels PX0 are shown as the predetermined number of pixels PX0 corresponding to a unit area. Of course, the predetermined number corresponding to a unit area is not limited to 36, and a larger area may be treated as the unit area. The left side of FIG. 4 shows an example in which ink droplets 237 are not discharged onto the predetermined number of pixels PX0 corresponding to the unit area. The right side of FIG. 4 shows an example in which dots DT0 of primary color ink are formed onto all pixels PX0 corresponding to the unit area. Pixels PX0 are the smallest elements constituting an image to which colors can be independently assigned. The ink discharge amount means the total amount of ink discharged per unit area. In other words, the ink discharge amount Duty means the ratio (including percentage) of the number of ink droplets 237 discharged to a predetermined number of pixels PX0, and means the ratio when converted to the largest ink droplet when ink droplets 237 of different sizes are discharged to the pixel PX0. For example, when Nd ink droplets 237 are discharged to 100 pixels, the ink discharge amount Duty is Nd%. When no ink droplets 237 are discharged to a predetermined number of pixels PX0 as shown on the left side of FIG. 4, Duty=0%, and when ink droplets 237 of the primary color are discharged to all pixels PX0 as shown on the right side of FIG. 4, Duty=100%. Note that when a mixed color image such as a secondary color is formed, multiple types of ink droplets 237 are discharged to one pixel PX0, so Duty may be greater than 100%. For example, the ink discharge amount Duty of the secondary color is a maximum of 200%.

[0036] Here, "ink color saturation" and "ink bleeding" will be explained. "Ink color saturation" refers to the phenomenon in which the color development hardly changes with the amount of ink ejected, in other words, the color development hardly changes even if the amount of ink ejected increases. "Color development" refers to the darkness of a printed image such as a patch, and is calculated by subtracting the lightness L of the Lab color space from 100 (100-L), and the saturation (a) obtained from the chromaticity coordinates a and b. 2 +b 2 ) 1 / 2, etc. "Ink bleeding" refers to a phenomenon in which ink ejected onto a certain area of ​​the medium ME0 is not absorbed by the medium ME0, and ink puddles form at the contours of the area, causing bumps. The control unit 110 of this specific example determines an upper limit Dt_final of the ejection amount per unit area at which bleeding of the ink 236 is permitted for the ink 236 ejected from the print head 230 onto the medium ME0.

[0037] Fig. 5 shows a schematic example of a patch having a line region for detecting the amount of bleeding. The left side of Fig. 5 shows a patch 510 in which no ink bleeding has occurred. The right side of Fig. 5 shows a patch 510 in which ink bleeding has occurred. The patch 510 includes two solid regions 531 and a line region 532 between these solid regions 531. The line region 532 is an example of a bleeding detection region of a target color for detecting the bleeding amount V1, and the solid region 531 is an example of a background region of a color different from that of the bleeding detection region. Each solid region 531 is a rectangular solid image of a color different from that of the line region 532, and is adjacent to the line region 532. In the patch 510 shown in FIG. 5, the colors of the multiple solid regions 531 are the same. The two solid regions 531 shown in FIG. 5 are separated into upper and lower parts, but may be separated into left and right parts, for example. The number of solid regions 531 included in each patch 510 may be three or more. The line region 532 is a linear solid image of a color different from that of the solid region 531, and is adjacent to both solid regions 531. The line region 532 is used to determine whether or not ink bleeding occurs.

[0038] Each pattern sequence P0 shown in FIG. 3 includes a plurality of patches 510, for example rectangular patches 511-515, in which the ink ejection amount to the solid region 531 and the line region 532 changes stepwise. The pattern sequence P11 includes a plurality of patches in which the ejection amount of K ink to the solid region 531 decreases stepwise from 100%, and the ejection amount of C ink to the line region 532 decreases stepwise from 100%. The pattern sequence P12 includes a plurality of patches in which the ejection amount of Y ink to the solid region 531 decreases stepwise from 100%, and the ejection amount of C ink to the line region 532 decreases stepwise from 100%. The pattern sequence P13 includes a plurality of patches in which the ejection amount of C ink to the solid region 531 decreases stepwise from 100%, and the ejection amount of M ink to the line region 532 decreases stepwise from 100%. The pattern array P14 includes a plurality of patches in which the ejection amount of M ink to the solid region 531 is gradually decreased from 100%, and the ejection amount of Y ink to the line region 532 is gradually decreased from 100%. The pattern array P15 includes a plurality of patches in which the ejection amount of Y ink to the solid region 531 is gradually decreased from 100%, and the ejection amount of K ink to the line region 532 is gradually decreased from 100%. The pattern array P16 includes a plurality of patches in which the ejection amount of K ink to the solid region 531 is gradually decreased from 100%, and the combined ejection amount of C ink and M ink to the line region 532 is gradually decreased from 100%. The pattern array P17 includes a plurality of patches in which the ejection amount of M ink to the solid region 531 is gradually decreased from 100%, and the combined ejection amount of C ink and Y ink to the line region 532 is gradually decreased from 100%. Pattern array P18 includes multiple patches in which the amount of C ink ejected into solid areas 531 is gradually decreased from 100%, and the amount of M ink and Y ink ejected combined into line areas 532 is gradually decreased from 100%. Pattern array P19 includes multiple patches in which no ink is ejected into solid areas 531, and the amount of C ink, M ink, and Y ink ejected combined into line areas 532 is gradually decreased from 100%.

[0039] As described above, pattern sequence P11 to P15 is pattern sequence P1 of primary color test pattern 501 in which the line regions 532 are primary colors, pattern sequence P16 to P18 is pattern sequence P2 of secondary color test pattern 502 in which the line regions 532 are secondary colors, and pattern sequence P19 is pattern sequence P3 of tertiary color test pattern 503 in which the line regions 532 are tertiary colors. The patches 510 of the pattern arrays P11 and P12 have in common the fact that they have line regions 532 of C ink. Therefore, the pattern arrays P11 and P12 configure an individual color test pattern 504 in which the line regions 532 of the patches 510 are individual colors included in the multiple colors that are primary colors. In this specific example, the individual colors included in the multiple colors that are primary colors are C, M, Y, and K. Also, the individual colors included in the multiple colors that are secondary colors include a combination of C and M, a combination of C and Y, and a combination of M and Y. The individual colors included in the multiple colors that are tertiary colors include a combination of C, M, and Y.

[0040] When the solid area 531 and the line area 532 are a primary color, the interval between the ink ejection amounts of the patches is not particularly limited and may be 5% intervals, 10% intervals, etc. When the line area 532 is a secondary color, the interval between the ink ejection amounts of the patches is not particularly limited and may be 10% intervals, 20% intervals, etc. Of course, the pattern sequence P0 is not limited to the example shown in Fig. 3. For example, the test pattern 500 may include a pattern sequence in which the line region 532 is C and the solid region 531 is M, or a pattern sequence in which the solid region 531 is a secondary color. Furthermore, the solid region 531 may be the bleeding detection region instead of the line region 532, and the line region 532 may be the background region instead of the solid region 531.

[0041] Fig. 5 shows a schematic example of bleeding that occurs in a patch 510. The left side of Fig. 5 shows a patch 510 formed on a medium ME1 that is resistant to ink bleeding. The right side of Fig. 5 shows a patch 510 formed on a medium ME2 that is resistant to ink bleeding. For example, glossy paper is an example of a medium ME1 that is resistant to ink bleeding, and plain paper and cloth are examples of a medium ME2 that is resistant to ink bleeding. The outline of the line region 532 formed on the medium ME1, which is less susceptible to ink bleeding, does not show any jaggedness due to bleeding. The outline of the line region 532 formed on the medium ME2, which is more susceptible to ink bleeding, shows jaggedness due to bleeding. In the medium ME2, which is more susceptible to ink bleeding, the ink in the line region 532 spreads to the surrounding area, so that the width w2 of the line region 532 formed on the medium ME2 is wider than the width w1 of the line region 532 formed on the medium ME1, which is less susceptible to ink bleeding. Therefore, the width of the line region 532 indicates the bleeding amount V1, which indicates the degree of bleeding, and it can be said that the wider the width of the line region 532, the greater the degree of bleeding. The greater the amount of ink ejected, the more likely ink bleeding is to occur.

[0042] 1 captures the patch 510, the upper limit determination unit 312 can obtain the width of the line region 532 as the bleeding amount V1 based on the imaging information 322. The upper limit determination unit 312 compares the bleeding amount V1 with a judgment threshold TH (see FIGS. 6 to 8), and determines that there is ink bleeding if V1>TH, and that there is no ink bleeding if V1≦TH. The upper limit determination unit 312 determines the maximum ink ejection amount that satisfies V1≦TH for each pattern sequence P0 as the provisional ejection amount upper limit Dt_p (see FIG. 8).

[0043] The judgment threshold TH (TH>0) used to judge the presence or absence of ink bleeding can be determined in advance by a plurality of testers (people who perform sensory evaluation) performing sensory evaluation of a plurality of test patterns printed on the medium ME0. For example, a plurality of types of test patterns including a patch 510 as shown in FIG. 5 are prepared corresponding to the degree of the width of the line region 532, and printed on the medium ME0. The tester performs sensory evaluation by visually checking the plurality of types of test patterns printed on the medium ME0 and selecting a patch in which the occurrence of ink bleeding is visually recognized. The judgment threshold TH is determined by statistically analyzing the results of the same sensory evaluation performed by the plurality of testers. When the judgment threshold TH is finally determined from the analysis result, a histogram is created in which the width of the line region 532 is a bin, and the width of the peak frequency may be set as the judgment threshold TH, or the weighted average value may be set as the judgment threshold TH. The design specifications of the printing device 1 may be taken into consideration for the judgment threshold TH. The presence or absence of ink bleeding is judged according to the obtained judgment threshold TH, thereby obtaining a result that matches human senses. The determined decision threshold TH is stored in the storage device 114.

[0044] The degree of bleeding in each patch 510 can vary greatly depending on the type of printing medium ME0, etc. In general, the bleeding amount V1 of the patch 510 formed on the medium ME1, which is less susceptible to ink bleeding, varies relatively little, while the bleeding amount V1 of the patch 510 formed on the medium ME2, which is more susceptible to ink bleeding, varies relatively much. When the discharge amount limit value is set for each color order, the printing head 230 has the nozzles 234 for C, M, Y, and K in different positions, as shown in FIG. 2, and therefore the bleeding amount V1 tends to vary between colors. This is thought to be because the landing state of the ink droplets 237 tends to vary between colors.

[0045] FIG. 6 shows a schematic example of how the upper discharge amount Dt_final is determined when the variation in the bleeding amount V1 is small, such as in the patch 510 formed on the medium ME1 where ink does not easily bleed. FIG. 7 shows a schematic example of how the upper discharge amount Dt_final is determined when the variation in the bleeding amount V1 is large, such as in the patch 510 formed on the medium ME2 where ink easily bleeds. In FIGS. 6 and 7, the horizontal axis is the ink discharge amount duty, and the vertical axis is the bleeding amount V1. In addition, "C / K", "M / K", and "Y / K" indicate "color of the line area 532 / color of the solid area 531". That is, "C / K" indicates a curve of the bleeding amount V1 obtained from the imaging result of the pattern array P1 for the primary color including a plurality of patches 510 having a C line area 532 and a K solid area 531 and having different ink discharge amount duties. "M / K" indicates the curve of the bleeding amount V1 obtained from the imaging result of the pattern array P1 for the primary color including multiple patches 510 having M line areas 532 and K solid areas 531 and different ink ejection amounts. "Y / K" indicates the curve of the bleeding amount V1 obtained from the imaging result of the pattern array P1 for the primary color including multiple patches 510 having Y line areas 532 and K solid areas 531 and different ink ejection amounts.

[0046] The upper limit determination unit 312 determines a provisional discharge amount upper limit Dt_p (see FIG. 8) which is a provisional value of the discharge amount upper limit Dt_final for each pattern sequence P1 based on the imaging results of the multiple patches 510 included in the pattern sequence P1. The provisional discharge amount upper limit Dt_p means the maximum ink discharge amount Duty at which the bleeding amount V1 does not exceed the judgment threshold TH for each pattern sequence P1. FIGS. 6 and 7 show that the provisional discharge amount upper limit Dt_p of "C / K" is the minimum value Dt_pmin, and the provisional discharge amount upper limit Dt_p of "Y / K" is the maximum value Dt_pmax. When the variation of the provisional discharge amount upper limit Dt_p is small as shown in FIG. 6, the upper limit determination unit 312 determines the minimum value Dt_pmin or the maximum value Dt_pmax as the discharge amount upper limit Dt_final.

[0047] 7, if the minimum value Dt_pmin is determined as the discharge rate upper limit value Dt_final when there is a large variation in the provisional discharge rate upper limit value Dt_p, color development decreases and the color gamut that can be expressed by the printer 200 narrows. Note that the pattern sequence P1 for which the minimum value Dt_pmin is determined has a patch 510 with a larger amount of bleeding V1 in the line region 532 than the remaining pattern sequence P1. When the color gamut of the printer 200 narrows, the color development of the printed image IM0 decreases significantly, and the image quality of the printed image IM0 deteriorates. On the other hand, the pattern sequence P1 for which the maximum value Dt_pmax is determined has a patch 510 with a smaller amount of bleeding V1 in the line region 532 than the remaining pattern sequence P1. Therefore, if the maximum value Dt_pmax is determined as the upper limit value Dt_final when there is a large variation in the provisional upper limit value Dt_p, the degree of bleeding of the ink 236 may become too large. If the degree of bleeding of the ink 236 becomes too large, the image quality of the print image IM0 will deteriorate.

[0048] Therefore, in the present specific example, the upper limit determination unit 312 determines the discharge rate upper limit Dt_final so that it is greater than the minimum value Dt_pmin and smaller than the maximum value Dt_pmax when the variation in the provisional discharge rate upper limit Dt_p is large. Whether the variation of the provisional discharge amount upper limit value Dt_p is large can be determined, for example, by whether the difference (Dt_pdif) between the maximum value Dt_pmax and the minimum value Dt_pmin exceeds a threshold value TH_Duty as an allowable range. When the difference Dt_pdif does not exceed the threshold value TH_Duty as shown in FIG. 6, the upper limit value determination unit 312 determines the minimum value Dt_pmin or the maximum value Dt_pmax as the discharge amount upper limit value Dt_final. When the difference Dt_pdif exceeds the threshold value TH_Duty as shown in FIG. 7, the upper limit value determination unit 312 determines the discharge amount upper limit value Dt_final to be larger than the minimum value Dt_pmin and smaller than the maximum value Dt_pmax. When the discharge amount upper limit value Dt_final is larger than the minimum value Dt_pmin, excessive deterioration of the color development of the print image IM0 is suppressed. The discharge amount upper limit value Dt_final is smaller than the maximum value Dt_pmax, which prevents excessive bleeding of the ink 236. Therefore, this specific example makes it possible to determine the discharge amount upper limit value Dt_final that prevents excessive deterioration in color development and excessive bleeding of the ink 236 even if the bleeding varies greatly.

[0049] (3) Example of ink discharge upper limit determination process: Fig. 8 shows a schematic example of the ink discharge amount upper limit determination process for determining the ink discharge amount upper limit Dt_final. Fig. 9 shows a schematic example of the print process performed by the printer 200 in step S104 of the ink discharge amount upper limit determination process. The ink discharge amount upper limit determination process will be described below with reference to Figs. 1 to 7. The ink discharge amount upper limit determination process of this specific example is performed by the host device 100 including the control unit 110 as shown in FIG. 1. The ink discharge amount upper limit determination process starts when the host device 100 receives an operation for determining the discharge amount upper limit Dt_final at the input device 115. Here, step S104 corresponds to the test pattern formation process ST1, the test pattern formation processing unit 311, and the test pattern formation processing function FU1. Steps S102, S106 to S118 correspond to the upper limit determination process ST2, the upper limit determination unit 312, and the upper limit determination function FU2. Step S120 corresponds to the allowable range update reception process ST3, the allowable range update reception unit 313, and the allowable range update reception function FU3. Step S122 corresponds to the judgment threshold change reception process ST4, the judgment threshold change reception unit 314, and the judgment threshold change reception function FU4. Hereinafter, the description of "step" may be omitted, and the step code may be shown in parentheses.

[0050] When the ink discharge amount upper limit determination process starts, the host device 100 acquires a threshold value TH_Duty for judging the variation of the provisional discharge amount upper limit value Dt_p and a judgment threshold value TH corresponding to the upper limit of the bleeding amount V1 (S102). The threshold value TH_Duty and the judgment threshold value TH are stored in the storage device 114 for each type of medium ME0. Therefore, the host device 100 may acquire a threshold value TH_Duty and a judgment threshold value TH corresponding to the type of medium ME0 on which the test pattern is to be printed from the list of the threshold values ​​TH_Duty and the judgment threshold values ​​TH from the storage device 114. Here, the threshold value TH_Duty includes a threshold value TH_Duty(n) for each order n of color, for example, a threshold value TH_Duty(1) for a primary color, a threshold value TH_Duty(2) for a secondary color, and a threshold value TH_Duty(3) for a tertiary color. The threshold value TH_Duty(n) is an example of an n-th order color tolerance range, which is a tolerance range for an n-th order color. The judgment threshold TH includes a judgment threshold TH(n) for each color order n, for example, a judgment threshold TH(1) for a primary color, a judgment threshold TH(2) for a secondary color, and a judgment threshold TH(3) for a tertiary color. The provisional discharge amount upper limit Dt_p includes an n-th color provisional discharge amount upper limit Dt_p(n) for the n-th color test pattern 50n, for example, a primary color provisional discharge amount upper limit Dt_p(1), a secondary color provisional discharge amount upper limit Dt_p(2), and a tertiary color provisional discharge amount upper limit Dt_p(3). In addition, the maximum value Dt_pmax of the provisional discharge amount upper limit Dt_p includes an n-th color maximum value Dt_pmax(n), which is the maximum value in the n-th color provisional discharge amount upper limit Dt_p(n). The minimum value Dt_pmin of the provisional ejection amount upper limit value Dt_p includes the n-th color minimum value Dt_pmin(n), which is the minimum value of the n-th color provisional ejection amount upper limit value Dt_p(n).

[0051] After S102, the host device 100 performs a process of making the printer 200 print a test pattern 500 including a pattern sequence P0 including a plurality of patches 510 with different ink ejection amount duties (S104). The test pattern 500 includes an n-th color test pattern 50n. The host device 100 transmits the test pattern data 321 shown in FIG. 1 to the printer 200. Here, it is assumed that the test pattern data 321 is RGB data. As shown in FIG. 9, the printer 200 first performs a resolution conversion process to convert the test pattern data 321 to the printing resolution (S202). If the test pattern data 321 is the printing resolution, the resolution conversion process is not necessary. Next, the printer 200 performs a color conversion process to convert the test pattern data 321 to ink amount data (S204). Note that if the test pattern data 321 is ink amount data, the color conversion process is not necessary. Next, the printer 200 performs a halftone process to convert the ink amount data to binary or quaternary dot data (S206). It should be noted that if the test pattern data 321 is dot data, halftone processing is not necessary. If necessary, the printer 200 performs a rasterization process to rearrange the dot data in printing order. Finally, the printer 200 generates a drive signal according to the dot data, and forms a test pattern 500 including a plurality of pattern arrays P0 corresponding to the test pattern data 321 on the medium ME0 (S208). The processes of S202 to S206 may be performed by the host device 100, the processes of S202 to S204 may be performed by the host device 100, or the process of S202 may be performed by the host device 100.

[0052] After printing the test pattern 500, the host device 100 causes the printer 200 to perform imaging, acquires imaging information 322 of the multiple patches 510 included in the test pattern 500 from the printer 200, and acquires the bleeding amount V1 from each piece of imaging information 322 (S106). Upon receiving the imaging instruction, the printer 200 backfeeds the medium ME0 and captures each patch 510 included in the test pattern 500 with the imaging unit 261. When the printer 200 transmits the imaging information 322 captured by the imaging unit 261 to the host device 100, the host device 100 acquires the imaging information 322 and stores it in the storage device 114. The host device 100 also calculates the bleeding amount V1 of each patch 510 based on the imaging information 322 and stores it in the storage device 114.

[0053] After S106, the host device 100 sets the order n for determining the discharge amount upper limit Dt_final (S108). Next, the host device 100 determines the n-th color provisional discharge amount upper limit Dt_p(n) by applying the judgment threshold TH(n) to the bleeding amount V1 for each pattern sequence P0 in the n-th color test pattern 50n (S110). The host device 100 can determine the maximum ink discharge amount duty for each pattern sequence P0 of the n-th color at which the bleeding amount V1 does not exceed the judgment threshold TH(n) as the n-th color provisional discharge amount upper limit Dt_p(n). Therefore, the process of S110 can be said to be a process of determining the n-th color provisional discharge amount upper limit Dt_p(n) by comparing the judgment threshold TH(n) and each bleeding amount V1 for each pattern sequence P0 of the n-th color. In this manner, the upper limit determination unit 312 determines the n-th color provisional ejection amount upper limit Dt_p(n) for each pattern sequence P0 in the n-th color test pattern 50n based on the reading results of the multiple patches 510 included in the pattern sequence P0.

[0054] After S110, the host device 100 calculates the difference Dt_pdif(n) between the n-th color maximum value Dt_pmax(n) and the n-th color minimum value Dt_pmin(n) among the multiple n-th color provisional discharge rate upper limit values ​​Dt_p(n) (S112). Next, the host device 100 determines whether the difference Dt_pdif(n) is equal to or smaller than the threshold value TH_Duty(n) for judging the variation (S114).

[0055] If the difference Dt_pdif(n) is equal to or smaller than the threshold value TH_Duty(n), the difference Dt_pdif(n) is within the n-th color tolerance range. In this case, the host device 100 determines the n-th color minimum value Dt_pmin(n) as the discharge rate upper limit value Dt_final(n) for the n-th color (S116). The host device 100 may determine the n-th color maximum value Dt_pmax(n) as the discharge rate upper limit value Dt_final(n) for the n-th color instead of the n-th color minimum value Dt_pmin(n). The host device 100 may display the determined discharge rate upper limit value Dt_final(n) on the display device 116. Since the host device 100 can simply set the nth color minimum value Dt_pmin(n) or the nth color maximum value Dt_pmax(n) as the ejection amount upper limit value Dt_final(n), the memory capacity required for the processing of S116 is small, and the time required for the processing of S116 is short.

[0056] If the difference Dt_pdif(n) is greater than the threshold TH_Duty(n), the difference Dt_pdif(n) exceeds the n-th color tolerance range. In this case, the host device 100 determines the median value of the multiple n-th color provisional discharge amount upper limit values ​​Dt_p(n) as the discharge amount upper limit value Dt_final(n) for the n-th color (S118). The "median value" means the n-th color provisional discharge amount upper limit value Dt_p(n) that is closest to the middle when the multiple n-th color provisional discharge amount upper limit values ​​Dt_p(n) are arranged in order of magnitude. If the number of n-th color provisional discharge amount upper limit values ​​Dt_p(n) is an even number, the host device 100 may determine one of the two n-th color provisional discharge amount upper limit values ​​Dt_p(n) that are closest to the middle as the discharge amount upper limit value Dt_final(n). In addition, since memory capacity for storing multiple n-th color provisional discharge amount upper limit values ​​Dt_p(n) is required to find the median value from multiple n-th color provisional discharge amount upper limit values ​​Dt_p(n), the process of S118 requires more memory capacity than the process of S116. Also, the host device 100 may determine the average value of multiple n-th color provisional discharge amount upper limit values ​​Dt_p(n) as the discharge amount upper limit value Dt_final(n) for the n-th color instead of the median value. The "average value" means a value obtained by averaging multiple n-th color provisional discharge amount upper limit values ​​Dt_p(n) and the number of orders n, such as the arithmetic mean value obtained by dividing the sum of multiple n-th color provisional discharge amount upper limit values ​​Dt_p(n) by the number of orders n. The process of S118 for determining the average value as the discharge amount upper limit value Dt_final(n) requires more memory capacity than the process of S116 and takes more time. On the other hand, the upper discharge rate Dt_final(n) is the above-mentioned median or average value, and is therefore greater than the n-th color minimum value Dt_pmin(n) and less than the n-th color maximum value Dt_pmax(n). The host device 100 may display the determined upper discharge rate Dt_final(n) on the display device 116.

[0057] After S116 or S118, the host device 100 may adjust the threshold value TH_Duty(n) for judging the variation as necessary (S120). In S120, the host device 100 can accept an operation to update the threshold value TH_Duty(n) through the input device 115 in FIG. 1, and can update the threshold value TH_Duty(n) in response to the operation.

[0058] Fig. 10 shows a schematic example of a UI (user interface) screen displayed in S120. A UI screen 700 shown in Fig. 10 has a primary color threshold input field 701, a secondary color threshold input field 702, a tertiary color threshold input field 703, an OK button 704, and the like. The host device 100 stores a threshold value TH_Duty(n) for judging the variation for an n-th color in the storage device 114. The initial threshold value TH_Duty(n) is a default value. In a primary color threshold input field 701, the host device 100 displays the primary color threshold TH_Duty(1) stored in the storage device 114 and accepts input of the threshold TH_Duty(1). In a secondary color threshold input field 702, the host device 100 displays the secondary color threshold TH_Duty(2) stored in the storage device 114 and accepts input of the threshold TH_Duty(2). In a tertiary color threshold input field 703, the host device 100 displays the tertiary color threshold TH_Duty(3) stored in the storage device 114 and accepts input of the threshold TH_Duty(3). When the host device 100 accepts an operation of an OK button 704 by the input device 115, it stores the operation content on the UI screen 700 in the storage device 114. If at least one of the thresholds TH_Duty(n) has been changed, the host device 100 returns the process to S114. As a result, the host device 100 determines in S114 whether the difference Dt_pdif(n) is equal to or smaller than the updated threshold TH_Duty(n).

[0059] For example, assume that the primary color threshold value TH_Duty(1) is 15%, the difference Dt_pdif(1) is 12%, and Dt_pdif(1)≦TH_Duty(1) is satisfied in S114, so that the primary color minimum value Dt_pmin(1) is determined and displayed as the upper limit value Dt_final(1) in S116. Here, assume that a user who understands the determined upper limit value Dt_final(1) wishes to improve the color development of the printed image IM0 by allowing a little more bleeding. To realize this desire, the effect can be obtained by making TH_Duty smaller and arbitrarily narrowing the selection range of the ink discharge amount Duty. In this example, if the user updates the primary color threshold value TH_Duty(1) to 10%, Dt_pdif(1)>TH_Duty(1) is satisfied in S114, so that the above-mentioned median or average value is determined as the upper limit value Dt_final(1) in S118. As a result, the updated upper limit Dt_final(1) becomes greater than the pre-update upper limit Dt_final(1)=Dt_pmin(1), improving the color development of the print image IM0. As described above, the user can update the allowable range of bleeding variation according to preference. The host device 100 performing the process of S120 can determine the ejection amount upper limit value Dt_final that reflects the user's preference.

[0060] Furthermore, the host device 100 may perform an adjustment process of the discharge rate upper limit Dt_final(n) as necessary (S122). In S122, the host device 100 can accept an operation to change the discharge rate upper limit Dt_final(n) via the input device 115 in Fig. 1, and can change the discharge rate upper limit Dt_final(n) in response to the operation. In addition, the host device 100 can change the judgment threshold TH(n) of the bleeding amount V1 to a judgment threshold corresponding to the changed discharge rate upper limit Dt_final(n).

[0061] 11 is a schematic diagram showing an example in which the determination threshold TH(n) is changed in accordance with the upper discharge amount limit Dt_final(n). In FIG. 11, the order n is 1, and each of the patches 510A and 510B has a line area 532 between solid areas 531. The upper part of Fig. 11 shows how the discharge amount upper limit Dt_final(n) is determined to be the provisional discharge amount upper limit Dt_pM of the patch 510A of "M / K" in S118 when the difference Dt_pdif(n) between the nth color maximum value Dt_pmax(n) and the nth color minimum value Dt_pmin(n) is greater than the threshold TH_Duty(n). The bleeding amount V1 of the patch 510A shown in the upper part of Fig. 11 is V1_final.

[0062] In S122, the host device 100 can accept an operation to specify the patch 510B corresponding to the new discharge amount upper limit value Dt_final(n) through the input device 115. The host device 100 can acquire the changed discharge amount upper limit value Dt_final(n) corresponding to the specified patch 510B. The lower part of FIG. 11 shows the state in which the patch 510B with the ink discharge amount duty "M / K" that is 5% larger than the provisional discharge amount upper limit value Dt_pM is specified. Since the ink discharge amount duty of the patch 510B is larger than that of the patch 510A, the bleeding amount V1_new of the patch 510B is larger than the bleeding amount V1_final of the patch 510A and is larger than the current judgment threshold value TH(n). In the above cases, the host device 100 changes the discharge amount upper limit Dt_final(n) from the provisional discharge amount upper limit Dt_pM to Dt_pM+5%, and stores the changed discharge amount upper limit Dt_final(n) in the storage device 114. In addition, the host device 100 updates the determination threshold TH(n) to the bleeding amount V1_new of the patch 510B, and stores the changed determination threshold TH(n) in the storage device 114. Therefore, the next time the ink discharge amount upper limit determination process is performed, the changed determination threshold TH(n) is applied to the bleeding amount V1 in S110.

[0063] In this manner, the host device 100 accepts changes to the determination threshold value TH. The user can change the degree of bleeding that is tolerated according to preference. The host device 100 that performs the process of S122 can determine the discharge amount upper limit value Dt_final that reflects the user's preference.

[0064] The host device 100 performs the processes of S108 to S122 for each order n. Therefore, if there is any order n for which the processes of S108 to S122 have not been performed, the host device 100 returns the process to S108 (S124). When the processes of S108 to S122 have been performed for all orders n, the host device 100 ends the ink discharge amount upper limit value determination process.

[0065] As described above, when the difference Dt_pdif(n) between the maximum value Dt_pmax(n) and the minimum value Dt_pmin(n) of the n-th color provisional discharge amount upper limit value Dt_p(n) is within the n-th color allowable range (TH_Duty(n)), one of the minimum value Dt_pmin(n) and the maximum value Dt_pmax(n) is determined as the discharge amount upper limit value Dt_final(n). When the difference Dt_pdif(n) between the maximum value Dt_pmax(n) and the minimum value Dt_pmin(n) exceeds the n-th color allowable range (TH_Duty(n)), the discharge amount upper limit value Dt_final(n) is determined to be greater than the minimum value Dt_pmin(n) and less than the maximum value Dt_pmax(n). The upper discharge amount limit value for the nth color is greater than the minimum value Dt_pmin(n) of the nth color provisional discharge amount limit value Dt_p(n), thereby preventing the color development of the print image IM0 from decreasing too much. The upper discharge amount limit value for the nth color is smaller than the maximum value Dt_pmax(n) of the nth color provisional discharge amount limit value Dt_p(n), thereby preventing the ink 236 from bleeding too much. Therefore, this specific example can determine the upper discharge amount limit value Dt_final that prevents the color development from decreasing too much or the ink 236 from bleeding too much, even if the bleeding varies greatly.

[0066] (4) Application examples: The discharge amount upper limit value Dt_final is not limited to being determined in units of the order n, and may be determined in units of individual colors included in a plurality of colors that are n-th order colors in the line region 532 of the patch 510. For example, Fig. 3 shows an individual color test pattern 504 in which the line region 532 of the patch 510 is the primary color C. Thus, the host device 100 may determine the discharge amount upper limit value Dt_final in units of C, in which the line region 532 of the patch 510 is included in the primary color. As another example, the individual color test pattern 504 for C may include a pattern sequence P1 of "C / M", a pattern sequence P1 of "C / Y", and a pattern sequence P1 of "C / K". The individual color test pattern 504 for M may include a pattern sequence P1 of "M / C", a pattern sequence P1 of "M / Y", and a pattern sequence P1 of "M / K". The individual color test pattern 504 for Y may include a pattern sequence P1 of "Y / C", a pattern sequence P1 of "Y / M", and a pattern sequence P1 of "Y / K". The individual color test pattern 504 for K may include a pattern sequence P1 of "K / C", a pattern sequence P1 of "K / M", and a pattern sequence P1 of "K / Y". Here, "color / color" such as "C / K" indicates "color of line area 532 / color of solid area 531".

[0067] 12 is a schematic diagram illustrating an ink ejection amount upper limit determination process for determining the ejection amount upper limit Dt_final(i) for each individual color i. Here, S304 corresponds to the test pattern formation process ST1, the test pattern formation processing unit 311, and the test pattern formation processing function FU1. S302, S306 to S318 correspond to the upper limit determination process ST2, the upper limit determination unit 312, and the upper limit determination function FU2. S320 corresponds to the allowable range update receiving process ST3, the allowable range update receiving unit 313, and the allowable range update receiving function FU3. S322 corresponds to the determination threshold change receiving process ST4, the determination threshold change receiving unit 314, and the determination threshold change receiving function FU4.

[0068] When the ink ejection amount upper limit determination process starts, the host device 100 acquires a threshold value TH_Duty for judging the variation of the provisional ejection amount upper limit value Dt_p and a judgment threshold value TH corresponding to the upper limit of the bleeding amount V1 (S302). Here, the threshold value TH_Duty includes a threshold value TH_Duty(i) for each individual color i, for example, a threshold value TH_Duty(1) for the primary color C, a threshold value TH_Duty(2) for the primary color M, a threshold value TH_Duty(3) for the primary color Y, a threshold value TH_Duty(4) for the primary color K, etc. Of course, the secondary and higher colors also include individual colors. The threshold value TH_Duty(i) is an example of an individual color tolerance range, which is a tolerance range for individual colors. The judgment threshold TH includes a judgment threshold TH(i) for each individual color i, for example, a judgment threshold TH(1) for the primary color C, a judgment threshold TH(2) for the primary color M, a judgment threshold TH(3) for the primary color Y, and a judgment threshold TH(4) for the primary color K. The provisional discharge amount upper limit Dt_p includes an individual color provisional discharge amount upper limit Dt_p(i) for the individual color test pattern 504, for example, a C provisional discharge amount upper limit Dt_p(1), an M provisional discharge amount upper limit Dt_p(2), a Y provisional discharge amount upper limit Dt_p(3), and a K provisional discharge amount upper limit Dt_p(4). In addition, the maximum value Dt_pmax of the provisional discharge amount upper limit Dt_p includes an individual color maximum value Dt_pmax(i), which is the maximum value in the individual color provisional discharge amount upper limit Dt_p(i). The minimum value Dt_pmin of the provisional ejection rate upper limit value Dt_p includes the individual color minimum value Dt_pmin(i), which is the minimum value of the individual color provisional ejection rate upper limit value Dt_p(i).

[0069] After S302, the host device 100 performs a process of causing the printer 200 to print an individual color test pattern 504 including a plurality of pattern arrays P0 including a plurality of patches 510 with different ink ejection duties (S304). Next, the host device 100 causes the printer 200 to perform imaging, acquires imaging information 322 of the plurality of patches 510 included in the test pattern 500 from the printer 200, and acquires the bleeding amount V1 from each imaging information 322 (S306).

[0070] After S306, the host device 100 sets an individual color i for which the discharge amount upper limit value Dt_final is determined (S308). Next, the host device 100 determines an individual color provisional discharge amount upper limit value Dt_p(i) by applying a judgment threshold value TH(i) to the bleeding amount V1 for each pattern sequence P0 in the individual color test pattern 504 (S310). The host device 100 can determine the maximum ink discharge amount duty for each pattern sequence P0 of the individual color at which the bleeding amount V1 does not exceed the judgment threshold value TH(i) as the individual color provisional discharge amount upper limit value Dt_p(i). Therefore, the process of S310 can be said to be a process of determining an individual color provisional discharge amount upper limit value Dt_p(i) by comparing the judgment threshold value TH(i) and each of the bleeding amounts V1 for each pattern sequence P0 of the individual color. In this manner, the upper limit determining unit 312 determines the individual color provisional ejection rate upper limit Dt_p(i) for each pattern sequence P0 in the individual color test pattern 504 based on the reading results of the multiple patches 510 included in the pattern sequence P0.

[0071] After S310, the host device 100 calculates the difference Dt_pdif(i) between the individual color maximum value Dt_pmax(i) and the individual color minimum value Dt_pmin(i) of the multiple individual color provisional ejection rate upper limit values ​​Dt_p(i) (S312). Next, the host device 100 determines whether the difference Dt_pdif(i) is equal to or smaller than the threshold value TH_Duty(i) for judging the variation (S314).

[0072] If the difference Dt_pdif(i) is equal to or smaller than the threshold value TH_Duty(i), the difference Dt_pdif(i) is within the individual color tolerance range. In this case, the host device 100 determines the individual color minimum value Dt_pmin(i) as the discharge amount upper limit value Dt_final(i) for the individual color (S316). The host device 100 may determine the individual color maximum value Dt_pmax(i) as the discharge amount upper limit value Dt_final(i) for the individual color instead of the individual color minimum value Dt_pmin(i). The host device 100 may display the determined discharge amount upper limit value Dt_final(i) on the display device 116. The host device 100 may set the individual color minimum value Dt_pmin(i) or the individual color maximum value Dt_pmax(i) as the discharge amount upper limit value Dt_final(i) as it is, so that the memory capacity required for the process of S316 is small, and the time required for the process of S316 is short.

[0073] If the difference Dt_pdif(i) is greater than the threshold TH_Duty(i), the difference Dt_pdif(i) exceeds the individual color tolerance range. In this case, the host device 100 determines the median value of the multiple individual color provisional discharge amount upper limit values ​​Dt_p(i) as the discharge amount upper limit value Dt_final(i) for the individual color (S318). Note that, since memory capacity is required to store the multiple individual color provisional discharge amount upper limit values ​​Dt_p(i) in order to find the median value from the multiple individual color provisional discharge amount upper limit values ​​Dt_p(i), the process of S318 requires more memory capacity than the process of S316. Also, the host device 100 may determine the average value of the multiple individual color provisional discharge amount upper limit values ​​Dt_p(i) as the discharge amount upper limit value Dt_final(i) for the individual color instead of the median value. The process of S318 for determining the average value as the upper discharge rate Dt_final(i) requires more memory capacity and takes more time than the process of S316. On the other hand, the upper discharge rate Dt_final(i) is greater than the individual color minimum value Dt_pmin(i) and less than the individual color maximum value Dt_pmax(i) because it is the median or average value described above. The host device 100 may display the determined upper discharge rate Dt_final(i) on the display device 116.

[0074] After S316 or S318, the host device 100 may adjust the threshold value TH_Duty(i) for judging the variation as necessary (S320). In S320, the host device 100 can accept an operation to update the threshold value TH_Duty(i) via the input device 115 in FIG. 1, and can update the threshold value TH_Duty(i) in response to the operation. Furthermore, the host device 100 may perform an adjustment process of the discharge amount upper limit value Dt_final(i) as necessary (S322). In S322, the host device 100 can accept an operation to change the discharge amount upper limit value Dt_final(i) via the input device 115 in Fig. 1, and can change the discharge amount upper limit value Dt_final(i) in response to the operation. In addition, the host device 100 can change the judgment threshold value TH(i) of the bleeding amount V1 to a judgment threshold value corresponding to the changed discharge amount upper limit value Dt_final(i).

[0075] If there remains any individual color i for which the processes of S308 to S322 have not been performed, the host device 100 returns the process to S308 (S324). When the processes of S308 to S322 have been performed for all individual colors i, the host device 100 ends the ink discharge amount upper limit value determination process.

[0076] As described above, when the difference Dt_pdif(i) between the maximum value Dt_pmax(i) and the minimum value Dt_pmin(i) of the individual color provisional discharge amount upper limit value Dt_p(i) is within the individual color allowable range (TH_Duty(i)), one of the minimum value Dt_pmin(i) and the maximum value Dt_pmax(i) is determined as the discharge amount upper limit value Dt_final(i). When the difference Dt_pdif(i) between the maximum value Dt_pmax(i) and the minimum value Dt_pmin(i) exceeds the individual color allowable range (TH_Duty(i)), the discharge amount upper limit value Dt_final(i) is determined to be greater than the minimum value Dt_pmin(i) and less than the maximum value Dt_pmax(i). The upper discharge amount limit value for each individual color is greater than the minimum value Dt_pmin(i) of the individual color provisional discharge amount limit value Dt_p(i), thereby preventing the color development of the print image IM0 from decreasing too much. The upper discharge amount limit value for each individual color is less than the maximum value Dt_pmax(i) of the individual color provisional discharge amount limit value Dt_p(i), thereby preventing the ink 236 from bleeding too much. Therefore, in this application example, it is possible to determine the upper discharge amount limit value Dt_final that prevents the color development from decreasing too much or the ink 236 from bleeding too much, even if the bleeding varies greatly.

[0077] (5) Variation: The present invention contemplates various modifications. For example, the ink color combination is not limited to C, M, Y, and K, and may include, in addition to C, M, Y, and K, one or more colors selected from Lc (light cyan) having a lower density than C, Lm (light magenta) having a lower density than M, Dy (dark yellow) having a higher density than Y, Lk (light black) having a lower density than K, Or (orange), Gr (green), transparent colors, etc. This technology is also applicable when some of C, M, Y, and K are not included in the ink color combination. The entity that performs the ink discharge amount upper limit determination process is not limited to a CPU, and may be an electronic component other than a CPU, such as an ASIC (Application Specific Integrated Circuit), etc. Of course, multiple CPUs may work together to perform the ink discharge amount upper limit determination process, or a CPU and another electronic component (e.g., an ASIC) may work together to perform the ink discharge amount upper limit determination process. The above-described processes can be changed as appropriate, such as by changing the order of the processes, etc. For example, in the ink ejection amount upper limit value determination process shown in Fig. 8, the process of S102 may be performed immediately after the process of S104. In the above-described processing, for example, a determination of whether or not it is "greater than" can be replaced with a determination of whether or not it is "greater than," and a determination of whether or not it is "less than" can be replaced with a determination of whether or not it is "less than" or not. Such replacement of determinations is also included in the present technology.

[0078] The reading unit that reads at least some of the patches included in the test pattern 500 is not limited to the imaging unit 261, but may be an image reading unit such as a scanner. The control unit 110 may determine the upper discharge amount Dt_final only for the primary color. In this case, the control unit 110 may treat the upper discharge amount of the secondary color as, for example, twice the upper discharge amount Dt_final of the primary color, and may treat the upper discharge amount of the tertiary color as, for example, three times the upper discharge amount Dt_final of the primary color.

[0079] (6) Conclusion: As described above, according to the present invention, it is possible to provide a technique capable of determining an upper limit of the discharge amount that prevents excessive deterioration of color development or excessive bleeding of the liquid even if there is a large variation in bleeding through various aspects. Of course, even a technique consisting only of the constituent elements according to the independent claims can obtain the basic functions and effects described above. In addition, configurations in which the configurations disclosed in the above examples are substituted with each other or the combination is changed, configurations in which the configurations disclosed in the publicly known techniques and the above examples are substituted with each other or the combination is changed, etc. The present invention also includes these configurations. [Explanation of symbols]

[0080] 1...printing device, 100...host device, 110...controller, 200...printer, 210...controller, 230...print head, 236...ink, 237...ink droplets, 250...driving unit, 261...imaging unit, 311...test pattern formation processing unit, 312...upper limit value determination unit, 313...tolerance range update reception unit, 314...judgment threshold change reception unit, 322...imaging information, 500...test pattern, 50n...nth-order color test pattern, 501...1 Secondary color test pattern, 502... secondary color test pattern, 503... tertiary color test pattern, 504... individual color test pattern, 510 to 515... patches, 531... solid area, 532... line area, 700... UI screen, D1... first direction, D2... second direction, DT0... dot, Dt_final, Dt_final(i), Dt_final(n)... upper limit of discharge amount, Dt_p... provisional upper limit of discharge amount, Dt_p(i)... provisional individual color discharge amount Upper limit, Dt_p(n)... nth color provisional ejection amount upper limit, Dt_pdif, Dt_pdif(i), Dt_pdif(n)... difference, Dt_pmax... maximum value, Dt_pmax(i)... individual color maximum value, Dt_pmax(n)... nth color maximum value, Dt_pmin... minimum value, Dt_pmin(i)... individual color minimum value, Dt_pmin(n)... nth color minimum value, IM0... print image, ME0, ME1, ME2... medium, P0, P1 to P3, P1 1 to P19...pattern sequence, PR0...printing control program, ST1...test pattern formation process, ST2...upper limit determination process, ST3...tolerance range update reception process, ST4...judgment threshold change reception process, TH_Duty...threshold (example of tolerance range), TH_Duty(i)...threshold (example of individual color tolerance range), TH_Duty(n)...threshold (example of nth color tolerance range), TH, TH(i), TH(n)...judgment threshold, V1...amount of bleeding, w1, w2...width.

Claims

1. 1. A method for determining an upper limit of a discharge amount per unit area of ​​a liquid discharged from a print head onto a medium, the method comprising the steps of: The liquid is of a plurality of different colors, a test pattern forming step of forming, on the medium, a test pattern including a pattern array including a plurality of patches having different ejection amounts, each of the patches including a bleeding detection region and a background region having a color different from that of the bleeding detection region; an upper limit value determination step of acquiring the read results of the plurality of patches included in the plurality of pattern sequences, and determining the upper limit value based on the read results of the plurality of patches, In the upper limit determination step, determining a provisional upper limit value of the upper limit for each of the pattern rows based on the reading results of the plurality of patches included in the pattern row; when a difference between a maximum value of the plurality of provisional discharge amount upper limit values ​​obtained for the plurality of pattern sequences and a minimum value of the plurality of provisional discharge amount upper limit values ​​is within an allowable range, determining one of the minimum value and the maximum value as the upper limit value; If the difference exceeds the allowable range, the upper limit is determined to be greater than the minimum value and less than the maximum value. Method for determining upper limit of discharge amount.

2. 2 . The method according to claim 1 , wherein, in the upper limit value determination step, if the difference exceeds the allowable range, an average value of the plurality of provisional discharge amount upper limits is determined as the upper limit value.

3. the test pattern includes an n-th color test pattern in which the bleeding detection area of ​​the patch is an n-th color, n being an integer that is equal to or greater than 1 and less than the number of types of liquid; the provisional ejection amount upper limit value includes an n-th color provisional ejection amount upper limit value for the n-th color test pattern, the tolerance range includes an n-th color tolerance range for the n-th color, In the upper limit determination step, determining the n-th color provisional ejection amount upper limit value for each of the pattern rows in the n-th color test pattern based on the reading results of the plurality of patches included in the pattern row; when a difference between an n-order color maximum value, which is the maximum value of the plurality of n-order color provisional ejection amount upper limit values, and an n-order color minimum value, which is the minimum value of the plurality of n-order color provisional ejection amount upper limit values, is within the n-order color tolerance range, one of the n-order color minimum value and the n-order color maximum value is determined as the upper limit value for the n-order color; if a difference between the n-th color maximum value and the n-th color minimum value exceeds the n-th color tolerance range, determining the upper limit value for the n-th color so as to be greater than the n-th color minimum value and less than the n-th color maximum value; The method for determining an upper limit value of a discharge amount according to claim 1 or 2.

4. the test pattern includes an individual color test pattern in which the bleeding detection area of ​​the patch is an individual color included in a plurality of colors that are n-th order colors, where n is an integer that is equal to or greater than 1 and less than the number of types of liquid; the provisional ejection rate upper limit value includes an individual color provisional ejection rate upper limit value for the individual color test pattern, the tolerances include individual color tolerances for the individual colors, In the upper limit determination step, determining the individual color provisional ejection amount upper limit value based on a reading result of the plurality of patches included in each pattern row in the individual color test pattern; when a difference between an individual color maximum value, which is the maximum value of the plurality of individual color provisional ejection rate upper limits, and an individual color minimum value, which is the minimum value of the plurality of individual color provisional ejection rate upper limits, is within the individual color tolerance range, one of the individual color minimum value and the individual color maximum value is determined as the upper limit value for the individual color; if the difference between the individual color maximum value and the individual color minimum value exceeds the individual color tolerance range, determining the upper limit value for the individual color so that the upper limit value is greater than the individual color minimum value and less than the individual color maximum value; The method for determining an upper limit value of a discharge amount according to claim 1 or 2.

5. 3. The method for determining an upper limit of a discharge amount according to claim 1, further comprising an allowable range update receiving step of receiving an operation for updating the allowable range and updating the allowable range in response to the operation.

6. In the upper limit value determination step, for each of the pattern arrays, a bleeding amount representing a degree of bleeding in the bleeding detection area included in each of the patches is obtained from a reading result of the plurality of patches included in the pattern array, and the provisional ejection amount upper limit value is determined by comparing each bleeding amount with a judgment threshold value corresponding to an upper limit of the bleeding amount; 3. The method for determining an upper limit of a discharge amount according to claim 1, further comprising a determination threshold change acceptance step of accepting a change to the determination threshold.

7. 3. The method according to claim 1, wherein in the upper limit value determination step, when the difference is within the allowable range, the minimum value is determined as the upper limit value.

8. A print head that ejects a plurality of different colored liquids onto a medium; a control unit that performs control to form, on the medium, a test pattern including a pattern array including a plurality of patches each having a different ejection amount per unit area for which bleeding of the liquid is permitted, the pattern array including a bleeding detection region and a background region of a color different from that of the bleeding detection region, acquires reading results of the plurality of patches included in the plurality of pattern arrays, and performs processing to determine an upper limit value of the ejection amount based on the reading results of the plurality of patches; A reading unit that reads the plurality of patches, The control unit is a first process for determining a provisional upper limit value of the ejection amount, which is a provisional value of the upper limit value, for each of the pattern arrays based on a reading result of the plurality of patches included in the pattern array; a second process of determining, when a difference between a maximum value of the plurality of provisional discharge amount upper limit values ​​obtained for the plurality of pattern sequences and a minimum value of the plurality of provisional discharge amount upper limit values ​​is within an allowable range, one of the minimum value and the maximum value as the upper limit value; and if the difference exceeds the allowable range, a third process is performed to determine the upper limit value so as to be greater than the minimum value and less than the maximum value. Printing device.

Images