Printing apparatus, image processing method, and program

Abstract

Determine the appropriate amount of reaction solution to be applied depending on the type of printing medium. [Solution] The printing apparatus includes an image printing unit 107 that prints an evaluation image on a printing medium to be evaluated by applying a reaction solution that reacts with the ink to an ink containing a colorant, and an application amount determination unit 308 that determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the evaluation image on the printing medium to be evaluated. The evaluation image includes a plurality of color development evaluation patch images for evaluating the color development of inks with different amounts of reaction solution applied, and a plurality of bleeding evaluation patch images for evaluating the bleeding of inks with different amounts of reaction solution applied. The application amount determination unit 308 determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the relationship between a plurality of color development evaluation values ​​calculated based on the plurality of color development evaluation patch images and a plurality of bleeding evaluation values ​​calculated based on the plurality of bleeding evaluation patch images.

Description

Technical Field

[0001] The present disclosure relates to a printing apparatus that performs printing by applying a reaction liquid to ink, an image processing method, and a program.

Background Art

[0002] A printing apparatus that discharges ink from a print head to print an image on a printing medium is known. Such a printing apparatus has been used in printing for various applications in recent years, and various types of printing media are used according to the application of printing. Note that the printing medium is also referred to as a recording medium.

[0003] Printing media include those that are difficult to absorb ink and those that are easy to absorb ink. In a printing medium that is difficult to absorb ink, the ink may bleed before it is fixed to the printing medium and seep out to surrounding pixels, resulting in a decrease in print quality. For example, in a printing medium that is difficult to absorb ink, beading or bleeding may occur, resulting in a decrease in print quality. Note that the beading phenomenon is a phenomenon in which adjacent ink dots are attracted to each other by the surface tension of the ink. The bleeding phenomenon is a phenomenon in which one color of ink seeps into another color of ink due to the difference in surface tension between the inks at the boundary where different colors of ink are adjacent. On the other hand, in a printing medium that is easy to absorb ink, the colorant contained in the ink may penetrate deep into the printing medium, making it difficult to obtain the color development property of the ink.

[0004] As a means for suppressing bleeding of ink and deterioration of color development property of ink on a printing medium, a technique of reacting an ink containing a colorant with a reaction liquid to insolubilize or aggregate the colorant contained in the ink is known. As a method of applying the reaction liquid, for example, a method of applying the reaction liquid using a coating roller, a method of discharging the reaction liquid from a print head in the same manner as ink, etc. have been proposed. Thereby, bleeding of ink and deterioration of color development property of ink on a printing medium can be suppressed, and a high-quality image can be realized.

[0005] The ink absorption capacity of printing media varies depending on the type of printing medium. Furthermore, even with printing media of the same material, ink absorption may differ depending on the brand of the printing medium. Therefore, if the appropriate amount of reaction solution is not applied according to the type of printing medium, the print quality may deteriorate.

[0006] For example, Patent Document 1 discloses a method for determining the amount of reaction solution to be applied according to the type of recording medium, based on the reading results of multiple ink images with different amounts of reaction solution applied. In the method described in Patent Document 1, an ink pattern containing both coated and uncoated areas is superimposed and recorded onto a pattern of reaction solution with different amounts applied. The amount of reaction solution to be applied is then determined by utilizing the fact that the density of the ink image changes depending on the difference in how the ink bleeds according to the amount of reaction solution applied. This makes it possible to determine an amount of reaction solution suitable for suppressing ink bleeding in recording media that do not easily absorb ink. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-35050 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, with conventional methods, even if the amount of reaction solution to be applied is determined considering ink bleeding, the ink absorbency of the printing medium may affect the color development of the ink. Therefore, considering only ink bleeding was insufficient to determine the appropriate amount of reaction solution to be applied depending on the type of printing medium.

[0009] This disclosure aims to determine the appropriate amount of reaction solution to be applied depending on the type of printing medium. [Means for solving the problem]

[0010] A printing apparatus according to one aspect of the present disclosure includes an image printing unit that prints an evaluation image on a printing medium to be evaluated by applying a reaction solution that reacts with the ink to an ink containing a colorant, and an application amount determination unit that determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the evaluation image on the printing medium to be evaluated, wherein the evaluation image includes a plurality of color development evaluation patch images for evaluating the color development of inks with different amounts of reaction solution applied to them, and a plurality of bleeding evaluation patch images for evaluating the bleeding of inks with different amounts of reaction solution applied to them, and the application amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on a relationship between a plurality of color development evaluation values ​​calculated based on the plurality of color development evaluation patch images and a plurality of bleeding evaluation values ​​calculated based on the plurality of bleeding evaluation patch images. [Effects of the Invention]

[0011] According to this disclosure, the appropriate amount of reaction solution to be applied can be determined depending on the type of printing medium. [Brief explanation of the drawing]

[0012] [Figure 1] This is a block diagram showing the hardware configuration of a printing system. [Figure 2] This is a schematic diagram of the image printing section. [Figure 3] This is a plan view of the print head. [Figure 4] This is a plan view illustrating the head module. [Figure 5] This is a block diagram showing the functional configuration of the image processing unit in the first embodiment. [Figure 6] This flowchart shows the process for printing user images. [Figure 7] This table shows the amount of reaction solution to be applied for each type of printing medium. [Figure 8] This is a flowchart showing the table generation process. [Figure 9] This is a schematic diagram showing an example of an evaluation image. [Figure 10]It is a schematic diagram showing an evaluation image printed on a printing medium with high ink absorbency. [Figure 11] It is a schematic diagram showing an evaluation image printed on a printing medium with low ink absorbency. [Figure 12] It is a graph showing the relationship between the amount of reaction liquid applied and the density of the evaluation image in a printing medium with high ink absorbency. [Figure 13] It is a graph showing the relationship between the amount of reaction liquid applied and the density of the evaluation image in a printing medium with low ink absorbency. [Figure 14] It is a flowchart showing the reaction liquid application amount determination process. [Figure 15] It is a flowchart showing a modified example of the reaction liquid application amount determination process. [Figure 16] It is a block diagram showing the functional configuration of the image processing unit in the second embodiment. [Figure 17] It is a table showing the amount of reaction liquid applied set for each type of printing medium. [Figure 18] It is a schematic diagram showing an example of an evaluation image.

Mode for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the present disclosure, and not all combinations of features described in the following embodiments are essential for the solution means of the present disclosure. Note that the same components will be described with the same reference numerals.

[0014] <<First Embodiment>> <Hardware Configuration of the Printing System> First, a printing system 1, which is an example of a printing apparatus according to this embodiment, will be described. Figure 1 is a block diagram showing the hardware configuration of the printing system 1. In this embodiment, a configuration that can determine the appropriate amount of reaction solution to be applied according to the type of printing medium will be described. As shown in Figure 1, the printing system 1 includes a CPU 100, RAM 101, ROM 102, operation unit 103, display unit 104, external storage device 105, image processing unit 106, image printing unit 107, image reading unit 108, I / F unit 109, and bus 110.

[0015] The CPU (Central Processing Unit) 100 controls the overall operation of the printing system 1 using the input data and the computer program stored in RAM 101 or ROM 102. In this embodiment, the CPU 100 controls the entire printing system 1, but this is not the only way. For example, the entire printing system 1 may be controlled by multiple hardware components sharing the processing.

[0016] The RAM (Random Access Memory) 101 has a storage area for temporarily storing computer programs or data read from the external storage device 105, data received from the outside via the I / F unit 109, etc. The RAM 101 is also used as a storage area by the CPU 100 when it performs various processes. Furthermore, the RAM 101 is used as a storage area by the image processing unit 106 when it performs image processing.

[0017] The ROM (Read Only Memory) 102 has a storage area for storing setting parameters for each part of the printing system 1, a boot program, and the like.

[0018] The control unit 103 is an input device such as a keyboard or mouse, and accepts operations (instructions) from the operator. By operating the control unit 103, the operator can input various instructions to the CPU 100.

[0019] The display unit 104 is a display device such as a liquid crystal display having a display screen. The display unit 104 can display the processing results of the CPU 100 as images, characters, etc. If the display unit 104 is a touch panel capable of detecting touch operations, the display unit 104 may function as part of the operation unit 103.

[0020] The external storage device 105 is a large-capacity information storage device, such as a hard disk drive. The external storage device 105 stores computer programs and data that allow the OS (operating system) or CPU 100 to execute various processes. The external storage device 105 also holds temporary data generated by the processing of each part. Examples of temporary data generated by the processing of each part include input / output image data and threshold matrices used by the image processing unit 106. The computer programs and data stored in the external storage device 105 are read as appropriate according to the control of the CPU 100 and stored in the RAM 101, and become the target of processing by the CPU 100.

[0021] The image processing unit 106 is implemented as a processor capable of executing computer programs or as a dedicated image processing circuit. The image processing unit 106 performs various image processing operations to convert the image data input as the target for printing into image data that can be output by the image printing unit 107, which will be described later. Alternatively, instead of providing a dedicated processor for the image processing unit 106, the CPU 100 may be configured to perform various image processing operations as the image processing unit 106.

[0022] The image printing unit 107 prints an image by ejecting ink and reaction liquid onto a printing medium based on image data received directly from the image processing unit 106, or image data received from the image processing unit 106 via the RAM 101 or external storage device 105. The printing medium can be any medium on which an image can be printed by depositing liquid droplets. Examples of printing media include printing paper, label paper, and envelope paper.

[0023] The image reading unit 108 is a reading sensor that reads the printed image on the printing medium printed by the image printing unit 107. In this embodiment, the image reading unit 108 is provided as an image sensor (line sensor) capable of reading the entire area of ​​the printing medium. However, the image reading unit 108 is not limited to an image sensor; an optical sensor capable of reading changes in the printed color of a predetermined area on the printing medium may also be provided. In this embodiment, the printed color refers to the density of the image (printed image) on the printing medium printed by the image printing unit 107.

[0024] The I / F (interface) unit 109 functions as an interface for connecting the printing system 1 with external devices. The I / F unit 109 also functions as an interface for exchanging data with communication devices using infrared communication, wireless LAN (Local Area Network), etc. The I / F unit 109 also functions as an interface for connecting to the internet. This allows the I / F unit 109 to exchange data with external devices, such as input images.

[0025] The CPU 100, RAM 101, ROM 102, operation unit 103, display unit 104, external storage device 105, image processing unit 106, image printing unit 107, image reading unit 108, and I / F unit 109 are all connected to the bus 110. The CPU 100, RAM 101, ROM 102, operation unit 103, display unit 104, external storage device 105, image processing unit 106, image printing unit 107, image reading unit 108, and I / F unit 109 can exchange data via the bus 110. In addition, some of the parts of the printing system 1 described above, such as the image printing unit 107 and the image reading unit 108, may be connected via the I / F unit 109.

[0026] <Hardware configuration of the image printing unit and image reading unit> Next, the image printing unit 107 and the image reading unit 108 will be described. Figure 2 is a schematic diagram of the image printing unit 107. The image printing unit 107 is an inkjet printing unit that prints an image by ejecting ink from the nozzles of the print head onto the printing medium. In Figures 2 to 4, the Z direction represents the vertical direction and intersects (orthogonal in this embodiment) with the XY plane defined by the X and Y directions. In this embodiment, the width direction of the printing medium MD is the X direction, and the transport direction of the printing medium MD is the Y direction.

[0027] As shown in Figure 2, the image printing unit 107 includes a first print head 201 corresponding to the reaction solution (P), and second to fifth print heads 202 to 205 corresponding to four ink colors: black (K), cyan (C), magenta (M), and yellow (Y). The first to fifth print heads 201 to 205 are formed extending in the width direction (X direction) of the printing medium MD and are positioned above the printing medium MD. The second print head 202 ejects black ink (K ink) toward the printing medium MD. The third print head 203 ejects cyan ink (C ink) toward the printing medium MD. The fourth print head 204 ejects magenta ink (M ink) toward the printing medium MD. The fifth print head 205 ejects yellow ink (Y ink) toward the printing medium MD. The first print head 201 ejects the reaction solution for fixing the ink onto the printing medium MD. The reaction solution is a colorless, transparent liquid that reacts with the ink containing the colorant to insolubilize or agglomerate the colorant contained in the ink. The second print head 202, third print head 203, fourth print head 204, and fifth print head 205 are arranged in this order downstream (+Y direction) of the first print head 201 in the transport direction. This allows ink droplets ejected from the second to fifth print heads 202 to 205 to land on the reaction solution on the printing medium MD coated by the first print head 201.

[0028] The print medium MD is transported in the transport direction (+Y direction) indicated by arrow 208 in Figure 2 by the rotation of transport rollers 206 (and other rollers not shown) driven by a motor (not shown). Ink and reaction liquid are ejected from multiple nozzles NZ (see, for example, Figure 4(b)) of the first to fifth print heads 201 to 205 onto the transported print medium MD according to the print data, thereby printing one raster image corresponding to the nozzle row of each print head. By repeating the ejection operation of each print head onto the transported print medium MD, for example, one page of image is printed on the print medium MD.

[0029] Figure 3 shows plan views of the first to fifth print heads 201 to 205. Figure 3(a) is a plan view of the first print head 201 as seen from the nozzle side. Figure 3(b) is a plan view of the second print head 202 as seen from the nozzle side. Figure 3(c) is a plan view of the third print head 203 as seen from the nozzle side. Figure 3(d) is a plan view of the fourth print head 204 as seen from the nozzle side. Figure 3(e) is a plan view of the fifth print head 205 as seen from the nozzle side.

[0030] As shown in Figure 3(a), the first print head 201 is composed of three first head modules 211 arranged along the width direction (X direction) of the printing medium MD. The first head modules 211 are offset from each other in the transport direction (Y direction) of the printing medium MD.

[0031] As shown in Figure 3(b), the second print head 202 is composed of three second head modules 221 arranged along the width direction (X direction) of the printing medium MD. The second head modules 221 in the second print head 202 are configured in the same way as the first head module 211 in the first print head 201.

[0032] As shown in Figure 3(c), the third print head 203 is composed of three third head modules 231 arranged along the width direction (X direction) of the printing medium MD. The third head modules 231 in the third print head 203 are configured in the same way as the first head module 211 in the first print head 201.

[0033] As shown in Figure 3(d), the fourth print head 204 is composed of three fourth head modules 241 arranged along the width direction (X direction) of the printing medium MD. The fourth head module 241 in the fourth print head 204 is configured similarly to the first head module 211 in the first print head 201.

[0034] As shown in Figure 3(e), the fifth print head 205 is composed of three fifth head modules 251 arranged along the width direction (X direction) of the printing medium MD. The fifth head module 251 in the fifth print head 205 is configured in the same way as the first head module 211 in the first print head 201.

[0035] Figure 4 is a plan view illustrating the first head module 211 in the first print head 201. Figure 4(a) is a plan view of the first head module 211. Figure 4(b) is a plan view of the chip module 212.

[0036] As shown in Figure 4(a), the first head module 211 is composed of five chip modules 212 arranged in the width direction (X direction) of the printing medium MD. As shown in Figure 4(b), each chip module 212 is equipped with 16 nozzles NZ for ejecting the reaction liquid (ink in the second to fifth print heads 202 to 205). The nozzles NZ are arranged in two rows in the width direction (X direction) of the printing medium MD. The resolution of the image formed by the droplet ejected from each nozzle NZ is 1200 dpi.

[0037] The image reading unit 108 shown in Figure 2 is a line sensor that covers the entire width of the printing medium MD. The image reading unit 108 is positioned downstream (+Y direction) in the transport direction from the first to fifth print heads 201 to 205. After the image is printed by the first to fifth print heads 201 to 205, the printing medium MD is transported to the image reading unit 108 by transport rollers 206, etc. The image reading unit 108 sequentially captures the printed image on the printing medium MD transported by the transport rollers 206, etc., and acquires it as, for example, RGB information, brightness information, etc. The image reading unit 108 stores the acquired RGB information, brightness information, etc. as two-dimensional image data in the external storage device 105.

[0038] <Functional Configuration of Image Processing Unit> Next, the image processing unit 106 will be described. Figure 5 is a block diagram showing the functional configuration of the image processing unit 106 in the first embodiment. As shown in Figure 5, the image processing unit 106 includes an image acquisition unit 301, a color separation processing unit 302, an information acquisition unit 303, a reaction solution image generation unit 304, and a halftone processing unit 305. Furthermore, the image processing unit 106 includes a reaction solution setting unit 306, an evaluation image generation unit 307, and an application amount determination unit 308.

[0039] The image acquisition unit 301 acquires an arbitrary input image specified by the user as a user image. The color separation processing unit 302 decomposes the RGB data of the input image acquired by the image acquisition unit 301 into 16-bit grayscale data (density data). The information acquisition unit 303 acquires the type of printing medium specified by the user. The reaction solution image generation unit 304 generates an image of the reaction solution (P), which will be described later. The halftone processing unit 305 performs quantization processing on the 16-bit CMYK image and the image of the reaction solution (P). The reaction solution setting unit 306 acquires the amount of reaction solution to be applied corresponding to the type of printing medium. The evaluation image generation unit 307 generates an evaluation image for determining the amount of reaction solution to be applied. The application amount determination unit 308 executes the reaction solution application amount determination process, which will be described later.

[0040] <Printing method> Next, we will describe a normal user image printing process as a printing method using the printing system 1 in this embodiment. Figure 6 is a flowchart showing the user image printing process.

[0041] First, in step S101, the image acquisition unit 301 of the image processing unit 106 acquires an arbitrary input image specified by the user as a user image. In this embodiment, the data of the input image is 8-bit image data each for red (R), green (G), and blue (B). Here, the 8-bit image data for each of RGB is collectively referred to as RGB data.

[0042] Next, in step S102, the color separation processing unit 302 decomposes the RGB data of the input image acquired by the image acquisition unit 301 into 16-bit gradation data (density data). At this time, the color separation processing unit 302 decomposes the RGB data of the input image into 16-bit gradation data (density data) for each of the ink colors of the printing device: cyan (C), magenta (M), yellow (Y), and black (K). As a result, a 16-bit CMYK image is obtained from an 8-bit input image (RGB image).

[0043] Next, in step S103, the information acquisition unit 303 acquires the type of printing medium specified by the user. The type of printing medium is input via the operation unit 103 through user operation.

[0044] Next, in step S104, the reaction solution setting unit 306 obtains the amount Rm of reaction solution to be applied, corresponding to the type of printing medium specified by the user, based on the type of printing medium obtained by the information acquisition unit 303. The amount of reaction solution to be applied is expressed as a percentage (%) of the grayscale value (pixel value) of the reaction solution image generated by the reaction solution image generation unit 304, which will be described later.

[0045] Figure 7 is a table showing the amount of reaction solution to be applied for each type of printing medium. For example, Figure 7 shows that when the type of printing medium is "MD1", the amount of reaction solution applied is set to 20%. Similarly, when the type of printing medium is "MD2", the amount of reaction solution applied is set to 38%. When the type of printing medium is "MD3", the amount of reaction solution applied is set to 36%. When the type of printing medium is "MD4", the amount of reaction solution applied is set to 42%. When the type of printing medium is "MD5", the amount of reaction solution applied is set to 22%. When the type of printing medium is "MD6", the amount of reaction solution applied is set to 18%. Also, when the type of printing medium is "Default", the amount of reaction solution applied is set to 30%. When the type of printing medium does not fall under any of "MD1", "MD2", "MD3", "MD4", "MD5", or "MD6", it falls under "Default".

[0046] If the reaction solution application amount table shown in Figure 7 holds the application amount Rm of the reaction solution corresponding to the type of printing medium specified by the user, the reaction solution setting unit 306 retrieves the application amount Rm of the reaction solution held in the reaction solution application amount table. If the reaction solution application amount table does not hold the application amount of the reaction solution corresponding to the type of printing medium specified by the user, the reaction solution setting unit 306 retrieves the application amount Rm of the reaction solution corresponding to the "default" in the reaction solution application amount table. Details of the table generation process for generating the reaction solution application amount table will be described later. In this embodiment, an example is shown in which the reaction solution setting unit 306 holds a table showing the application amount of the reaction solution set for each type of printing medium, but it is not limited to this. For example, a table showing the application amount of the reaction solution set for each type of printing medium may be stored in an external device, and the reaction solution setting unit 306 may retrieve the application amount of the reaction solution corresponding to the type of printing medium specified by the user from the external device.

[0047] Returning to Figure 6, in the next step S105, the reaction solution image generation unit 304 generates an image of the reaction solution (P) based on the CMYK image obtained by the color separation processing unit 302. At this time, a 16-bit image of the reaction solution is generated by setting the pixel value to 65535 × Rm at pixel positions where the pixel value is greater than 0 in the CMYK image, and setting the pixel value to 0 at all other pixel positions. This generates an image of the reaction solution so that the reaction solution is applied to a certain area of ​​the image (ink).

[0048] Next, in step S106, the halftone processing unit 305 performs quantization on the 16-bit CMYK image and the image of the reaction solution (P). By performing quantization on the 16-bit CMYK image and the image of the reaction solution (P), the halftone processing unit 305 generates 1-bit print data (binary dot data) of CMYK+P. In this embodiment, for example, a known dithering method is used for quantization. However, the quantization process is not limited to the dithering method; other pseudo-halftone processing methods such as error diffusion may also be used.

[0049] Next, in step S107, the image printing unit 107 drives the first to fifth print heads 201 to 205 based on the dot data obtained by the halftone processing unit 305, and ejects ink and reaction liquid of each color onto the printing medium MD to print the user image. Once printing by the image printing unit 107 is complete, a printed product PM is obtained with the user image (input image) printed on the printing medium MD.

[0050] Next, we will explain the table generation process for generating a table of reaction solution application amounts. Figure 8 is a flowchart of the table generation process.

[0051] First, in step S201, the evaluation image generation unit 307 of the image processing unit 106 obtains an initial value Rd for the amount of reaction solution to be applied. In this embodiment, the amount of reaction solution applied is set to 100% when one dot of the reaction solution is placed in all of the 1200 dpi pixels in the binary image. Also, the initial value Rd for the amount of reaction solution to be applied is set to 30%.

[0052] Next, in step S202, the evaluation image generation unit 307 generates an evaluation image for determining the amount of reaction solution to be applied. The evaluation image is a 16-bit CMYK(+P) image. Figure 9 is a schematic diagram showing an example of an evaluation image.

[0053] As shown in Figure 9, the evaluation image includes multiple color development evaluation patch images A1 to A7 for evaluating the color development of the color ink, and multiple bleeding evaluation patch images B1 to B7 for evaluating the bleeding of the color ink. In this embodiment, the multiple color development evaluation patch images A1 to A7 and the multiple bleeding evaluation patch images B1 to B7 are printed using black ink, overlaid on images of multiple reaction solutions with different amounts of each other. Multiple reaction solution patterns R1 to R7 are generated from the images of multiple reaction solutions with different amounts of each other, and the multiple color development evaluation patch images A1 to A7 and the multiple bleeding evaluation patch images B1 to B7. The amount of each reaction solution in the multiple reaction solution pattern images R1 to R7 is set to increase or decrease around an initial value Rd of the amount of each reaction solution. In Figure 9, the magnitude of the amount of each reaction solution is represented by shades of gray.

[0054] In the example shown in Figure 9, in the pattern image R1 of the first reaction solution, the first color development evaluation patch image A1 and the first blurring evaluation patch image B1 are printed overlaid on an image of the reaction solution where the amount of reaction solution applied is set to 0.4 times (12%) the initial value Rd of the amount of reaction solution applied. In the pattern image R2 of the second reaction solution, the second color development evaluation patch image A2 and the second blurring evaluation patch image B2 are printed overlaid on an image of the reaction solution where the amount of reaction solution applied is set to 0.6 times (18%) the initial value Rd of the amount of reaction solution applied. In the pattern image R3 of the third reaction solution, the third color development evaluation patch image A3 and the third blurring evaluation patch image B3 are printed overlaid on an image of the reaction solution where the amount of reaction solution applied is set to 0.8 times (24%) the initial value Rd of the amount of reaction solution applied. In the pattern image R4 for the fourth reaction solution, the fourth color development evaluation patch image A4 and the fourth blurring evaluation patch image B4 are printed over an image of the reaction solution with the application amount set to the initial value Rd (30%). In the pattern image R5 for the fifth reaction solution, the fifth color development evaluation patch image A5 and the fifth blurring evaluation patch image B5 are printed over an image of the reaction solution with the application amount set to 1.2 times (36%) the initial value Rd. In the pattern image R6 for the sixth reaction solution, the sixth color development evaluation patch image A6 and the sixth blurring evaluation patch image B6 are printed over an image of the reaction solution with the application amount set to 1.4 times (42%) the initial value Rd. In the pattern image R7 of the seventh reaction solution, the seventh color development evaluation patch image A7 and the seventh bleeding evaluation patch image B7 are printed over the image of the reaction solution, which is set to an amount 1.6 times (48%) of the initial amount Rd of the reaction solution applied.

[0055] In the example shown in Figure 9, pattern images R1 to R7 of the first to seventh reaction solutions are generated by increasing or decreasing the amount of reaction solution in seven steps, but this is not the only example. It is desirable to generate multiple pattern images of reaction solutions by increasing or decreasing the amount of reaction solution within a sufficient number of steps and upper and lower limits to determine the amount of reaction solution to be added.

[0056] The color evaluation patch image is a pattern image used to evaluate the decrease in color development due to ink penetration. As the color evaluation patch image, a solid pattern in which at least one type of ink covers the printing medium can be used, such as the solid patterns shown in the first to seventh color evaluation patch images A1 to A7 in Figure 9. In the example shown in Figure 9, the first to seventh color evaluation patch images A1 to A7 are printed using one type of ink (black ink), but this is not the only option. For example, a solid pattern of cyan ink with magenta ink overlaid may be used for the color evaluation patch image. Note that the more ink used, the more reaction solution is needed to suppress ink penetration. Therefore, it is desirable that the color evaluation patch image be generated using a single-color pattern with a duty cycle of 100%, or a mixed-color pattern with the maximum duty cycle within the printable range on the printing medium.

[0057] The patch image for evaluating bleeding is a pattern image used to evaluate ink bleeding due to the beading or bleeding phenomenon described above. As the patch image for evaluating bleeding, repeating patterns such as grid patterns and striped patterns can be used, as shown in the first to seventh patch images B1 to B7 of Figure 9. In the example shown in Figure 9, the first to seventh patch images B1 to B7 are printed using one type of ink (black ink), but this is not the only option. For example, the patch image for evaluating bleeding may be a pattern image in which a grid pattern of black ink is superimposed on a solid pattern of yellow ink. The patch image for evaluating bleeding may be a pattern image in which a grid pattern of yellow ink and a grid pattern of black ink are exclusively arranged. Various patterns can be used as patch images for evaluating bleeding, in which areas where at least one type of ink covers the printing medium and areas where at least one type of ink does not cover the printing medium are mixed.

[0058] Furthermore, the first to seventh color evaluation patch images A1 to A7 and the first to seventh bleeding evaluation patch images B1 to B7 are formed in a single row in the transport direction (Y direction) of the printing medium. In other words, the first to seventh color evaluation patch images A1 to A7 are arranged in a single row in the transport direction (Y direction) of the printing medium, and the first to seventh bleeding evaluation patch images B1 to B7 are arranged in a single row parallel to the first to seventh color evaluation patch images A1 to A7. As a result, the nozzles used in the second to fifth print heads 202 to 205 are the same in the first to seventh color evaluation patch images A1 to A7 and the first to seventh bleeding evaluation patch images B1 to B7. Therefore, it is possible to eliminate factors that cause changes in printed color due to differences in the amount of ink ejected from each nozzle, and it becomes easier to identify the degree of change in printed color due to the amount of reaction solution applied.

[0059] Alternatively, evaluation images may be generated for all ink color combinations to determine the amount of reaction solution to apply. Or, evaluation images may be generated only for ink colors where print quality is important, and the amount of reaction solution to apply may be determined accordingly.

[0060] Returning to Figure 8, in the next step S203, the halftone processing unit 305 performs quantization on the evaluation image, which includes the color evaluation patch image and the bleeding evaluation patch image mentioned above. By performing quantization on the evaluation image, the halftone processing unit 305 generates 1-bit print data (binary dot data) for 5 planes of CMYK+P.

[0061] Next, in step S204, the image printing unit 107 drives the first to fifth print heads 201 to 205 based on the dot data obtained by the halftone processing unit 305, and ejects inks and reaction solutions of each color onto the printing medium to be evaluated to print the evaluation image. Once printing by the image printing unit 107 is complete, an evaluation printout is obtained with the evaluation image printed on the printing medium to be evaluated.

[0062] Figure 10 is a schematic diagram showing evaluation images printed on MDa, a printing medium with high ink absorption. MDa is, for example, uncoated paper. As shown in Figure 10, in the first to seventh color development evaluation patch images A1a to A7a printed on MDa, the printed color changes depending on the amount of reaction solution applied. This is because, on MDa, a printing medium with high ink absorption, the more reaction solution is applied, the more effectively the colorants in the ink can penetrate into the interior of the printing medium. On the other hand, in the first to seventh bleeding evaluation patch images B1a to B7a printed on MDa, the ink bleeding is minimal and the change in printed color is small, regardless of the amount of reaction solution applied. Therefore, from the first to seventh color development evaluation patch images A1a to A7a, which are used to evaluate the color development of the ink, we identify the color development evaluation patch image with sufficiently high ink color development (density). This allows the amount of reaction solution applied to correspond to the identified color evaluation patch image to be determined to be the appropriate amount for the highly ink-absorbent printing medium MDa.

[0063] Furthermore, the highly ink-absorbent printing medium MDa has the first color development evaluation patch image A1a and the first bleeding evaluation patch image B1a printed on it, with the amount of reaction solution applied set to 12%. The highly ink-absorbent printing medium MDa has the second color development evaluation patch image A2a and the second bleeding evaluation patch image B2a printed on it, with the amount of reaction solution applied set to 18%. The highly ink-absorbent printing medium MDa has the third color development evaluation patch image A3a and the third bleeding evaluation patch image B3a printed on it, with the amount of reaction solution applied set to 24%. The highly ink-absorbent printing medium MDa has the fourth color development evaluation patch image A4a and the fourth bleeding evaluation patch image B4a printed on it, with the amount of reaction solution applied set to 30%. The highly ink-absorbent printing medium MDa has the fifth color development evaluation patch image A5a and the fifth bleeding evaluation patch image B5a printed on it, with the amount of reaction solution applied set to 36%. The highly ink-absorbent printing medium MDa has the sixth color development evaluation patch image A6a and the sixth bleeding evaluation patch image B6a printed on it, with the amount of reaction solution applied set to 42%. The highly ink-absorbent printing medium MDa has the seventh color development evaluation patch image A7a and the seventh bleeding evaluation patch image B7a printed on it, with the amount of reaction solution applied set to 48%.

[0064] Figure 11 is a schematic diagram showing evaluation images printed on a printing medium MDb with low ink absorption. A printing medium MDb with low ink absorption is, for example, coated paper. As shown in Figure 11, in the first to seventh color evaluation patch images A1b to A7b printed on the printing medium MDb with low ink absorption, ink penetration is small and the change in printed color is small, regardless of the amount of reaction solution applied. On the other hand, in the first to seventh bleeding evaluation patch images B1b to B7b printed on the printing medium MDb with low ink absorption, the printed color changes according to the amount of reaction solution applied. This is because, on the printing medium MDb with low ink absorption, the more reaction solution is applied, the more effectively the bleeding of ink from the grid pattern can be suppressed. Therefore, from the first to seventh bleeding evaluation patch images B1b to B7b, we identify the bleeding evaluation patch image that can sufficiently suppress ink bleeding. This allows the amount of reaction solution applied to the identified patch image for bleeding evaluation to be determined to be an amount suitable for the MDb printing medium, which has low ink absorption.

[0065] Furthermore, the first color development evaluation patch image A1b and the first bleeding evaluation patch image B1b, with the amount of reaction solution applied set to 12%, are printed on the printing medium MDb with low ink absorption. The second color development evaluation patch image A2b and the second bleeding evaluation patch image B2b, with the amount of reaction solution applied set to 18%, are printed on the printing medium MDb with low ink absorption. The third color development evaluation patch image A3b and the third bleeding evaluation patch image B3b, with the amount of reaction solution applied set to 24%, are printed on the printing medium MDb with low ink absorption. The fourth color development evaluation patch image A4b and the fourth bleeding evaluation patch image B4b, with the amount of reaction solution applied set to 30%, are printed on the printing medium MDb with low ink absorption. Printing medium MDb, which has low ink absorption, has the fifth color development evaluation patch image A5b and the fifth bleeding evaluation patch image B5b printed on it, with the amount of reaction solution applied set to 36%. Printing medium MDb, which has low ink absorption, has the sixth color development evaluation patch image A6b and the sixth bleeding evaluation patch image B6b printed on it, with the amount of reaction solution applied set to 42%. Printing medium MDb, which has low ink absorption, has the seventh color development evaluation patch image A7b and the seventh bleeding evaluation patch image B7b printed on it, with the amount of reaction solution applied set to 48%.

[0066] Returning to Figure 8, in the next step S205, the image reading unit 108 captures the evaluation image on the print medium to be evaluated, which has been printed by the image printing unit 107. In this embodiment, the evaluation image (read image) acquired by the image reading unit 108 is an 8-bit RGB image with a resolution of 1200 dpi.

[0067] Next, in step S206, the amount determination unit 308 performs a reaction solution amount determination process and determines the amount of reaction solution to be applied to the print medium to be evaluated based on the print color data in the reading data of the evaluation image read by the image reading unit 108. Details of the reaction solution amount determination process will be described later.

[0068] Then, in step S207, the reaction solution setting unit 306 stores the amount of reaction solution to be dispensed, determined by the dispensed amount determination unit 308, in association with the type of printing medium being evaluated. For example, if the type of printing medium being evaluated is "MD1" and the amount of reaction solution to be dispensed is determined to be 20%, the reaction solution dispensed amount table shown in Figure 7 will store the type of printing medium "MD1" and the amount of reaction solution to be dispensed when the type of printing medium is "MD1" "20%".

[0069] <Process for determining the amount of reaction solution to be supplied> Next, as an image processing method in this embodiment, the reaction solution application amount determination process performed by the application amount determination unit 308 of the image processing unit 106 will be described. Based on the print color data of the evaluation image read by the image reading unit 108, the application amount determination unit 308 calculates an evaluation value for color development to evaluate the color development of the ink and an evaluation value for bleeding to evaluate the bleeding of the ink, and determines an appropriate amount of reaction solution to apply.

[0070] In this embodiment, the color development evaluation value is the printed color of the color development evaluation patch image read by the image reading unit 108, in other words, the density of the color development evaluation patch image on the printing medium to be evaluated. The bleeding evaluation value is the printed color of the bleeding evaluation patch image read by the image reading unit 108, in other words, the density of the bleeding evaluation patch image on the printing medium to be evaluated. When calculating the color development evaluation value and bleeding evaluation value for multiple types of ink, it is desirable to use the density of the color development evaluation patch image and the density of the bleeding evaluation patch image in the wavelength band that is easily absorbed by the ink, depending on the type of ink.

[0071] In printing media that readily absorb ink, i.e., printing media with high ink absorption, the colorants contained in the ink penetrate deep into the printing media. Therefore, when the amount of reaction solution applied is small, the density of the patch image used for color evaluation will be low. As the amount of reaction solution applied increases, the density of the patch image used for color evaluation gradually increases. However, as the penetration of ink into the printing media decreases, the change in the density of the patch image becomes smaller even when the amount of reaction solution applied increases. In other words, in printing media with high ink absorption, the more reaction solution applied, the higher the density of the patch image used for color evaluation, which is an evaluation value for color development, and the more effectively the ink's color development is suppressed. Thus, the higher the density of the patch image used for color evaluation, or in other words, the larger the evaluation value for color development, the better the evaluation.

[0072] On the other hand, in printing media that do not absorb ink well, i.e., printing media with low ink absorption, ink bleeds out from the grid-like pattern, resulting in a higher density of the patch image used for bleeding evaluation. As the amount of reaction solution applied increases, the density of the patch image used for bleeding evaluation gradually decreases, but as ink bleeding decreases, the change in density of the patch image becomes smaller even if the amount of reaction solution applied increases. In other words, in printing media with low ink absorption, the more reaction solution applied, the lower the density of the patch image used for bleeding evaluation, which is used as an evaluation value for bleeding, and the more effectively ink bleeding can be suppressed. Thus, the lower the density of the patch image used for bleeding evaluation, or in other words, the smaller the bleeding evaluation value, the better the evaluation value.

[0073] Figure 12 is a graph showing the relationship between the amount of reaction solution applied and the density of the evaluation image in a printing medium with high ink absorption. Figure 12(a) is a graph showing the relationship between the amount of reaction solution applied and the density of the color development evaluation patch image in a printing medium with high ink absorption. Figure 12(b) is a graph showing the relationship between the amount of reaction solution applied and the density of the bleeding evaluation patch image in a printing medium with high ink absorption. The horizontal axis of the graphs in Figures 12(a) and 12(b) represents the amount of reaction solution applied corresponding to the pattern images R1 to R7 of multiple reaction solutions in the evaluation image. The vertical axis of the graph in Figure 12(a) represents the density of the color development evaluation patch image. The vertical axis of the graph in Figure 12(b) represents the density of the bleeding evaluation patch image.

[0074] As shown in Figure 12(a), in printing media with high ink absorbency, the density of the patch image used for color evaluation increases as the amount of reaction solution applied increases, and the evaluation value for color development shows a good rating. On the other hand, as shown in Figure 12(b), in printing media with high ink absorbency, the ink is absorbed into the printing media before it can bleed, so the evaluation value for bleeding does not change significantly even if the amount of reaction solution applied increases. However, because the density of the patch image used for bleeding evaluation increases as the ink's color development improves, the evaluation value for bleeding tends to show a slightly lower rating.

[0075] Figure 13 is a graph showing the relationship between the amount of reaction solution applied and the density of the evaluation image in a printing medium with low ink absorption. Figure 13(a) is a graph showing the relationship between the amount of reaction solution applied and the density of the color development evaluation patch image in a printing medium with low ink absorption. Figure 13(b) is a graph showing the relationship between the amount of reaction solution applied and the density of the bleeding evaluation patch image in a printing medium with low ink absorption. The horizontal axis of the graphs in Figures 13(a) and 13(b) represents the amount of reaction solution applied corresponding to the pattern images R1 to R7 of multiple reaction solutions in the evaluation image. The vertical axis of the graph in Figure 13(a) represents the density of the color development evaluation patch image. The vertical axis of the graph in Figure 13(b) represents the density of the bleeding evaluation patch image.

[0076] As shown in Figure 13(b), in printing media with low ink absorption, as the amount of reaction solution applied increases, the density of the patch image used for bleeding evaluation decreases, and the bleeding evaluation value shows a good rating. On the other hand, as shown in Figure 13(a), in printing media with low ink absorption, ink penetration is small, so even if the amount of reaction solution applied increases, the color development evaluation value does not change significantly. However, because the ink fixes before bleeding, the surface of the printing media is exposed, and the density of the patch image used for color development evaluation decreases, so the color development evaluation value tends to show a slightly lower rating. In this way, by utilizing the changes in density of the patch image used for color development evaluation and the patch image used for bleeding evaluation in relation to the amount of reaction solution applied, it is possible to determine the appropriate amount of reaction solution to apply for the printing media being evaluated.

[0077] Figure 14 is a flowchart showing the reaction solution application amount determination process. First, in step S301, the application amount determination unit 308 of the image processing unit 106 acquires the reading values ​​(pixel values) of the first to seventh color evaluation patch images A1 to A7 as reading data of the read image (evaluation image) acquired by the image reading unit 108. The application amount determination unit 308 also acquires the reading values ​​(pixel values) of the first to seventh blur evaluation patch images B1 to B7 as reading data of the read image acquired by the image reading unit 108.

[0078] Next, in step S302, the amount determination unit 308 calculates a color development evaluation value, which is an evaluation index for the color development of the ink, from the readings of the first to seventh color development evaluation patch images A1 to A7 obtained in step S301. At this time, the amount determination unit 308 calculates a color development evaluation value for each of the first to seventh color development evaluation patch images A1 to A7. As a result, the densities of the first to seventh color development evaluation patch images A1 to A7 on the printing medium to be evaluated are calculated as multiple color development evaluation values ​​with different amounts of reaction solution applied to each other.

[0079] Next, in step S303, the application amount determination unit 308 calculates an evaluation value for ink bleeding, which is an evaluation index for ink bleeding, from the readings of the first to seventh bleeding evaluation patch images B1 to B7 acquired in step S301. At this time, the application amount determination unit 308 calculates an evaluation value for bleeding for each of the first to seventh bleeding evaluation patch images B1 to B7. As mentioned above, the density of the bleeding evaluation patch image is calculated as the bleeding evaluation value. In this way, the densities of the first to seventh bleeding evaluation patch images B1 to B7 on the printing medium to be evaluated are calculated as multiple bleeding evaluation values ​​with different amounts of reaction solution applied to each other.

[0080] In this embodiment, the density of each patch image (color evaluation patch image or blurring evaluation patch image) is defined as OD. Gav is defined as the average value of the G channel of each patch image among the RGB channels of the read image acquired by the image reading unit 108. In this case, the density OD of each patch image is calculated using the following formula. OD = -log 10 (Gav / Gw)

[0081] Here, Gw may be the average value of the G channel of the surface portion (e.g., margin) of the printed medium in the read image. Gw may also be the maximum value corresponding to the number of bits in the read image (255 in the case of 8 bits). The density OD of each patch image may be calculated using the average value of the R channel, or the average value of the B channel, not limited to the average value of the G channel.

[0082] Furthermore, when each patch image (color evaluation patch image or bleeding evaluation patch image) is printed using cyan ink, the R channel of the RGB channel of the read image is used. When each patch image is printed using magenta ink, the G channel of the RGB channel of the read image is used. When each patch image is printed using yellow ink, the B channel of the RGB channel of the read image is used. This makes it possible to obtain the density of the color evaluation patch image and the bleeding evaluation patch image in the wavelength range that is easily absorbed by the ink, depending on the type of ink.

[0083] Next, in step S304, the amount determination unit 308 calculates the amount Ra of the reaction solution to be applied based on the color development evaluation value calculated in step S302. The amount Ra of the reaction solution to be applied based on the color development evaluation value is calculated based on whether or not the color development evaluation value (concentration) has reached equilibrium. The amount determination unit 308 derives a first threshold Ta from the color development evaluation value calculated in step S302, and determines whether or not the color development evaluation value has reached equilibrium by comparing the color development evaluation value of each color development evaluation patch image A1 to A7 with the first threshold Ta. In this embodiment, the first threshold Ta is derived using the formula "Ta = maximum value - (maximum value - minimum value) × 5%". The "maximum value" in the formula is the maximum value of the color development evaluation value. The "minimum value" in the formula is the minimum value of the color development evaluation value. The amount determination unit 308 then determines the smallest amount of reaction solution to be applied to the color evaluation patch image among the color evaluation patch images A1 to A7 whose color evaluation value exceeds the first threshold Ta, as the amount of reaction solution to be applied Ra based on the color evaluation value.

[0084] For example, in the example shown in Figure 12(a), the amount of reaction solution Ra determined based on the color development evaluation value (concentration) is the amount of reaction solution applied corresponding to the pattern image R5 of the fifth reaction solution (38%). In the example shown in Figure 13(a), the amount of reaction solution Ra determined based on the color development evaluation value (concentration) is the amount of reaction solution applied corresponding to the pattern image R1 of the first reaction solution (12%). Alternatively, the minimum amount of reaction solution applied that results in a color development evaluation value exceeding the first threshold Ta may be calculated by performing various interpolation processes on the amount of reaction solution applied corresponding to the color development evaluation patch image whose color development evaluation value exceeds the first threshold Ta. The minimum amount of reaction solution applied that results in a color development evaluation value exceeding the first threshold Ta may then be determined as the amount of reaction solution Ra based on the color development evaluation value.

[0085] Next, in step S305, the amount determination unit 308 calculates the amount Rb of the reaction solution to be applied based on the evaluation value of the bleeding calculated in step S303. The amount Rb of the reaction solution to be applied based on the evaluation value of the bleeding is calculated based on whether or not the evaluation value (concentration) of the bleeding has reached equilibrium. The amount determination unit 308 derives a second threshold Tb from the evaluation value of the bleeding calculated in step S304, and determines whether or not equilibrium has been reached by comparing the evaluation value of the bleeding of each bleeding evaluation patch image B1 to B7 with the second threshold Tb. In this embodiment, the second threshold Tb is derived using the formula "Tb = minimum value + (maximum value - minimum value) × 5%". The "maximum value" in the formula is the maximum value of the bleeding evaluation value. The "minimum value" in the formula is the minimum value of the bleeding evaluation value. The application amount determination unit 308 then determines the smallest amount of reaction solution to be applied among the patch images B1 to B7 for each blur evaluation, corresponding to the patch image in which the blur evaluation value does not exceed the second threshold Tb, as the amount of reaction solution to be applied Rb based on the blur evaluation value.

[0086] For example, in the example shown in Figure 12(b), the amount of reaction solution Rb determined based on the evaluation value (concentration) of the blurring is the amount of reaction solution (12%) corresponding to the pattern image R1 of the first reaction solution. In the example shown in Figure 13(b), the amount of reaction solution Rb determined based on the evaluation value (concentration) of the blurring is the amount of reaction solution (24%) corresponding to the pattern image R3 of the third reaction solution. Alternatively, the minimum amount of reaction solution that results in a blurring evaluation value not exceeding the second threshold Tb may be calculated by performing various interpolation processes on the amount of reaction solution corresponding to the blurring evaluation patch image in which the blurring evaluation value does not exceed the second threshold Tb. Then, the minimum amount of reaction solution that results in a blurring evaluation value not exceeding the second threshold Tb may be determined as the amount of reaction solution Rb based on the blurring evaluation value.

[0087] Then, in step S306, the amount determination unit 308 determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the amount of reaction solution Ra determined based on the evaluation value of color development, and the amount of reaction solution Rb determined based on the evaluation value of bleeding. At this time, the amount determination unit 308 determines the amount of reaction solution to be applied to the printing medium to be evaluated as the larger of the amount of reaction solution Ra determined based on the evaluation value of color development and the amount of reaction solution Rb determined based on the evaluation value of bleeding. For example, as shown in Figures 12(a) and 12(b), in the case of a printing medium with high ink absorption, Ra = 38% and Rb = 12%, so the amount of reaction solution to be applied to the printing medium to be evaluated is determined to be 38% (Ra), whichever is larger of Ra and Rb. As shown in Figures 13(a) and 13(b), for printing media with low ink absorption, Ra = 12% and Rb = 24%. Therefore, the amount of reaction solution applied to the printing media under evaluation is determined to be 24% (Rb), whichever is greater than Ra. As can be seen from Figures 12(a), 12(b), 13(a), and 13(b), determining the amount of reaction solution to be applied based on the greater of Ra and Rb does not significantly affect the color development or ink bleeding of the ink, which corresponds to the smaller of Ra and Rb.

[0088] By performing the processing control described above, according to this embodiment, when determining the amount of reaction solution to be applied, it is possible not only to evaluate the ink bleeding in accordance with the amount of reaction solution applied, but also to evaluate the decrease in ink color development in accordance with the amount of reaction solution applied. Therefore, it is possible to determine an appropriate amount of reaction solution to be applied according to the type of printing medium, regardless of the type of printing medium, whether it is a printing medium that absorbs ink easily or a printing medium that does not easily absorb ink.

[0089] As described above, according to this embodiment, it is possible to determine an appropriate amount of reaction solution to be applied depending on the type of printing medium. Specifically, in this embodiment, the amount of reaction solution to be applied to the printing medium to be evaluated is determined based on the relationship between multiple color development evaluation values ​​calculated based on multiple color development evaluation patch images and multiple bleeding evaluation values ​​calculated based on multiple bleeding evaluation patch images. This makes it possible to evaluate not only the ink bleeding according to the amount of reaction solution applied using the bleeding evaluation value when determining the amount of reaction solution to be applied, but also the decrease in ink color development according to the amount of reaction solution applied using the color development evaluation value. Therefore, it is possible to determine an appropriate amount of reaction solution to be applied depending on the type of printing medium, regardless of whether it is a printing medium that absorbs ink easily or not, and regardless of the type of printing medium. In this way, it is possible to determine an appropriate amount of reaction solution to be applied depending on the type of printing medium.

[0090] <Modified method for determining the amount of reaction solution to be applied> In the first embodiment described above, the amount of reaction solution to be applied to the printing medium under evaluation is determined to be the larger of the two amounts of reaction solution applied, Ra, based on the evaluation value of color development, and Rb, based on the evaluation value of bleeding. However, it is not limited to this. Next, a modified version of the reaction solution application amount determination process will be described. Figure 15 is a flowchart showing a modified version of the reaction solution application amount determination process.

[0091] First, in step S401, the amount determination unit 308 acquires the readings of the first to seventh color development evaluation patch images A1 to A7 and the readings of the first to seventh bleeding evaluation patch images B1 to B7, similar to step S301 of the first embodiment. Next, in step S402, the amount determination unit 308 calculates the color development evaluation value, which is an evaluation index for the color development of the ink, similar to step S302 of the first embodiment. Next, in step S403, the amount determination unit 308 calculates the bleeding evaluation value, which is an evaluation index for the bleeding of the ink, similar to step S303 of the first embodiment.

[0092] Next, in step S404, the amount determination unit 308 determines whether the color development of the ink, in other words, the evaluation value of color development, improves as the amount of reaction solution is increased. At this time, the amount determination unit 308 determines whether the evaluation value of the color development of the seventh color development evaluation patch image A7 is greater than the evaluation value of the color development of the first color development evaluation patch image A1 among several evaluation values ​​of color development. If the evaluation value of the color development of the seventh color development evaluation patch image A7 is greater than the evaluation value of the color development of the first color development evaluation patch image A1, and the evaluation value of color development has improved, that is, if the determination in step S404 is YES, the process proceeds to step S405. If the evaluation value of the color development of the seventh color development evaluation patch image A7 is less than or equal to the evaluation value of the first color development evaluation patch image A1, and the evaluation value of color development has not improved, that is, if the determination in step S404 is NO, the process proceeds to step S406.

[0093] If the process proceeds to step S405, the application amount determination unit 308 determines the amount of reaction solution to be applied to the printing medium under evaluation based on the color development evaluation value. At this time, the application amount determination unit 308 calculates the amount of reaction solution to be applied, Ra, based on the color development evaluation value calculated in step S402, in the same manner as in step S304 of the first embodiment. The application amount determination unit 308 then determines the amount of reaction solution to be applied, Ra, which is determined based on multiple color development evaluation values, as the amount of reaction solution to be applied to the printing medium under evaluation. Note that if the color development evaluation value improves with increasing amount of reaction solution applied, the printing medium under evaluation is likely to be a printing medium with high ink absorption. For this reason, it is possible to determine the amount of reaction solution to be applied to the printing medium under evaluation based on multiple color development evaluation values.

[0094] If the process proceeds to step S406, the application amount determination unit 308 determines the amount of reaction solution to be applied to the printing medium under evaluation based on the bleeding evaluation value. At this time, the application amount determination unit 308 calculates the amount of reaction solution Rb based on the bleeding evaluation value calculated in step S403, in the same manner as in step S305 of the first embodiment. The application amount determination unit 308 then determines the amount of reaction solution Rb, which is determined based on multiple bleeding evaluation values, as the amount of reaction solution to be applied to the printing medium under evaluation. If the color development evaluation value does not improve with increasing the amount of reaction solution applied, it is highly likely that the printing medium under evaluation is a printing medium with low ink absorption. For this reason, it is possible to determine the amount of reaction solution to be applied to the printing medium under evaluation based on multiple bleeding evaluation values.

[0095] According to the above-described modification, similar to the first embodiment, the appropriate amount of reaction solution to be applied can be determined depending on the type of printing medium.

[0096] In the modified example described above, if the evaluation value of color development improves, the amount of reaction solution to be applied is determined based on multiple evaluation values ​​of color development, and if the evaluation value of color development does not improve, the amount of reaction solution to be applied is determined based on multiple evaluation values ​​of bleeding, but it is not limited to this. For example, the application amount determination unit 308 may determine whether the ink bleeding, or in other words the bleeding evaluation value, improves as the amount of reaction solution applied increases. In this case, the application amount determination unit 308 determines whether the bleeding evaluation value of the seventh bleeding evaluation patch image B7 is smaller than the bleeding evaluation value of the first bleeding evaluation patch image B1 among the multiple bleeding evaluation values. If the bleeding evaluation value of the seventh bleeding evaluation patch image B7 is smaller than the bleeding evaluation value of the first bleeding evaluation patch image B1, and the bleeding evaluation value has improved, the amount of reaction solution to be applied is determined based on multiple evaluation values ​​of bleeding. If the bleeding evaluation value improves as the amount of reaction solution applied increases, it is highly likely that the printing medium being evaluated is a printing medium with low ink absorption. Therefore, it is possible to determine the amount of reaction solution to apply to the printing medium under evaluation based on multiple bleeding evaluation values. On the other hand, if the bleeding evaluation value of the seventh bleeding evaluation patch image B7 is greater than or equal to the bleeding evaluation value of the first bleeding evaluation patch image B1, and the bleeding evaluation value has not improved, the amount of reaction solution to apply is determined based on multiple color development evaluation values. If the bleeding evaluation value does not improve with increasing the amount of reaction solution applied, it is highly likely that the printing medium under evaluation is a printing medium with high ink absorption. Therefore, it is possible to determine the amount of reaction solution to apply to the printing medium under evaluation based on multiple color development evaluation values.

[0097] <<Second Embodiment>> Next, a second embodiment will be described. Except for a part of the image processing unit 106, the individual components in the second embodiment have the same configuration as those in the first embodiment described above, and will therefore be described using the same reference numerals as those used for each component in the first embodiment. In the first embodiment, an example of determining the amount of reaction solution to be applied when the type of printing medium is unknown was described. In the second embodiment, an example of determining an appropriate amount of reaction solution to be applied according to the type of printing medium when the type of printing medium can be determined to some extent will be described. Here, the type of printing medium refers to differences in the surface quality of the printing medium, such as coated paper and uncoated paper. The type of printing medium refers to differences in the individual brands of the printing medium. The type of printing medium is determined by the user, and the type of printing medium determined by the user is input via the operation unit 103.

[0098] Figure 16 is a block diagram showing the functional configuration of the image processing unit 106 in the second embodiment. As shown in Figure 16, the image processing unit 106 in the second embodiment includes an image acquisition unit 301, a color separation processing unit 302, an information acquisition unit 303, a reaction solution image generation unit 304, and a halftone processing unit 305. Furthermore, the image processing unit 106 in the second embodiment includes a reaction solution setting unit 406, an evaluation image generation unit 407, and an application amount determination unit 308.

[0099] In the second embodiment, the user image printing process, table generation process, and reaction solution application amount determination process are performed, similar to the first embodiment. The second embodiment will be described focusing on the differences from the first embodiment, and similar points will not be explained.

[0100] In step S104 of the user image printing process, the reaction solution setting unit 406 in the second embodiment can obtain the amount of reaction solution to be applied according to the type of printing medium (default). Figure 17 is a table showing the amount of reaction solution to be applied for each type of printing medium in the second embodiment. The table shown in Figure 17 holds the amount of reaction solution to be applied according to the type of printing medium (default). For example, Figure 17 shows that when the type of printing medium is "MD1", the amount of reaction solution to be applied is set to 38%. Similarly, it shows that when the type of printing medium is "MD2", the amount of reaction solution to be applied is set to 36%. When the type of printing medium is "MD3", the amount of reaction solution to be applied is set to 42%. When the type of printing medium is "MD4", the amount of reaction solution to be applied is set to 20%. When the type of printing medium is "MD5", the amount of reaction solution to be applied is set to 22%. When the type of printing medium is "MD6", the amount of reaction solution to be applied is set to 18%. Furthermore, although the type of printing medium is unknown, if the type of printing medium is uncoated paper (default), the amount of reaction solution applied will be set to 40%. Although the type of printing medium is unknown, if the type of printing medium is coated paper (default), the amount of reaction solution applied will be set to 20%.

[0101] If the reaction solution dispensing amount table shown in Figure 17 contains the reaction solution dispensing amount Rm corresponding to the type of printing medium specified by the user, the reaction solution setting unit 406 retrieves the reaction solution dispensing amount Rm stored in the reaction solution dispensing amount table. If the reaction solution dispensing amount table does not contain the reaction solution dispensing amount corresponding to the type of printing medium specified by the user, the reaction solution setting unit 406 retrieves the reaction solution dispensing amount Rm according to the type of printing medium (default).

[0102] In step S201 of the table generation process, the evaluation image generation unit 407 in the second embodiment acquires the amount of reaction solution to be applied according to the type of printing medium (default) as the initial value Rd of the amount of reaction solution applied. If the type of printing medium is uncoated paper, the initial value Rd of the amount of reaction solution applied is 40%. If the type of printing medium is coated paper, the initial value Rd of the amount of reaction solution applied is 20%.

[0103] In step S202 of the table generation process, the evaluation image generation unit 407 in the second embodiment generates an evaluation image for determining the amount of reaction solution to be applied. Figure 18 is a schematic diagram showing an example of an evaluation image in the second embodiment.

[0104] As shown in Figure 18, multiple color development evaluation patch images A1-A7 and multiple bleeding evaluation patch images B1-B7 are printed over images of multiple reaction solutions with different application amounts, similar to the first embodiment. Multiple reaction solution pattern images R1-R7, each with different application amounts, are generated from the images of multiple reaction solutions with different application amounts, and the multiple color development evaluation patch images A1-A7 and multiple bleeding evaluation patch images B1-B7. The application amounts of the reaction solutions in the multiple reaction solution pattern images R1-R7 are set to increase or decrease around an initial value Rd of the application amount. If the type of printing medium can be determined, the range of increase or decrease in the application amount of the reaction solution can be narrower than in the first embodiment.

[0105] In the second embodiment, examples of pattern images R1 to R7 for the first to seventh reaction solutions when the printing medium is uncoated paper will be described. In the pattern image R1 for the first reaction solution, the first color development evaluation patch image A1 and the first bleeding evaluation patch image B1 are printed over an image of the reaction solution in which the amount of reaction solution applied is set to 0.7 times (28%) the initial value Rd of the amount of reaction solution applied. In the pattern image R2 for the second reaction solution, the second color development evaluation patch image A2 and the second bleeding evaluation patch image B2 are printed over an image of the reaction solution in which the amount of reaction solution applied is set to 0.8 times (32%) the initial value Rd of the amount of reaction solution applied. In the pattern image R3 for the third reaction solution, the third color development evaluation patch image A3 and the third bleeding evaluation patch image B3 are printed over an image of the reaction solution in which the amount of reaction solution applied is set to 0.9 times (36%) the initial value Rd of the amount of reaction solution applied. In the pattern image R4 for the fourth reaction solution, the fourth color development evaluation patch image A4 and the fourth blurring evaluation patch image B4 are printed over an image of the reaction solution with the application amount set to the initial value Rd (40%). In the pattern image R5 for the fifth reaction solution, the fifth color development evaluation patch image A5 and the fifth blurring evaluation patch image B5 are printed over an image of the reaction solution with the application amount set to 1.1 times (44%) the initial value Rd. In the pattern image R6 for the sixth reaction solution, the sixth color development evaluation patch image A6 and the sixth blurring evaluation patch image B6 are printed over an image of the reaction solution with the application amount set to 1.2 times (48%) the initial value Rd. In the pattern image R7 of the seventh reaction solution, the seventh color development evaluation patch image A7 and the seventh bleeding evaluation patch image B7 are printed over an image of the reaction solution, where the amount of solution applied is set to 1.3 times (52%) the initial value Rd of the amount of solution applied.

[0106] In the second embodiment, examples of pattern images R1 to R7 for the first to seventh reaction solutions when the printing medium is coated paper will be described. In the pattern image R1 for the first reaction solution, the first color development evaluation patch image A1 and the first bleeding evaluation patch image B1 are printed over an image of the reaction solution with the amount of reaction solution applied set to 0.7 times (14%) the initial value Rd of the amount of reaction solution applied. In the pattern image R2 for the second reaction solution, the second color development evaluation patch image A2 and the second bleeding evaluation patch image B2 are printed over an image of the reaction solution with the amount of reaction solution applied set to 0.8 times (16%) the initial value Rd of the amount of reaction solution applied. In the pattern image R3 for the third reaction solution, the third color development evaluation patch image A3 and the third bleeding evaluation patch image B3 are printed over an image of the reaction solution with the amount of reaction solution applied set to 0.9 times (18%) the initial value Rd of the amount of reaction solution applied. In the pattern image R4 for the fourth reaction solution, the fourth color development evaluation patch image A4 and the fourth blurring evaluation patch image B4 are printed over an image of the reaction solution with the application amount set to the initial value Rd (20%). In the pattern image R5 for the fifth reaction solution, the fifth color development evaluation patch image A5 and the fifth blurring evaluation patch image B5 are printed over an image of the reaction solution with the application amount set to 1.1 times (22%) the initial value Rd. In the pattern image R6 for the sixth reaction solution, the sixth color development evaluation patch image A6 and the sixth blurring evaluation patch image B6 are printed over an image of the reaction solution with the application amount set to 1.2 times (24%) the initial value Rd. In the pattern image R7 of the seventh reaction solution, the seventh color development evaluation patch image A7 and the seventh bleeding evaluation patch image B7 are printed over the image of the reaction solution, which is set to an amount 1.3 times (26%) of the initial amount Rd of the reaction solution applied.

[0107] According to the second embodiment, similar to the first embodiment, the appropriate amount of reaction solution to be applied can be determined according to the type of printing medium. Furthermore, according to the second embodiment, if the type of printing medium can be identified, the range of increase or decrease in the amount of reaction solution applied can be narrowed, making it possible to determine the amount of reaction solution to be applied to the printing medium being evaluated with high accuracy.

[0108] Furthermore, similar to the modification of the first embodiment, the amount determination unit 308 may determine the amount of reaction solution to be applied to the printing medium under evaluation based on the multiple color development evaluation values ​​if the color development evaluation value improves with increasing amount of reaction solution applied in one of the multiple color development evaluation values. Alternatively, if the color development evaluation value does not improve with increasing amount of reaction solution applied in one of the multiple color development evaluation values, the amount determination unit 308 may determine the amount of reaction solution to be applied to the printing medium under evaluation based on the multiple bleeding evaluation values.

[0109] Similar to other modifications of the first embodiment, the amount determination unit 308 may determine the amount of reaction solution to be applied to the printing medium under evaluation based on the multiple bleeding evaluation values ​​if the bleeding evaluation value improves with increasing amount of reaction solution applied in one of the multiple bleeding evaluation values. Alternatively, the amount determination unit 308 may determine the amount of reaction solution to be applied to the printing medium under evaluation based on the multiple color development evaluation values ​​if the bleeding evaluation value does not improve with increasing amount of reaction solution applied in one of the multiple bleeding evaluation values.

[0110] In each of the embodiments described above, the density of the evaluation image on the print medium is calculated from the readings of the evaluation image (color evaluation patch image and bleeding evaluation patch image), but this is not limited to this. For example, other indicators that reflect the effects of ink bleeding and ink color development, such as the brightness of the evaluation image on the print medium and the L*a*b* color difference, may be calculated from the readings of the evaluation image.

[0111] In each of the embodiments described above, the amount of reaction solution dispensed is expressed as a percentage (%) of the grayscale value (pixel value) of the reaction solution image generated by the reaction solution image generation unit 304, but is not limited to this. For example, the amount of reaction solution dispensed may be expressed using the grayscale value of the reaction solution image itself, or it may be expressed using the amount of reaction solution injected per unit area. When the amount of reaction solution injected per unit area is used, a conversion is performed from the amount of reaction solution dispensed in one go to the grayscale value of the reaction solution image.

[0112] In each of the embodiments described above, the first to fifth print heads 201 to 205 are so-called full-line print heads capable of ejecting ink or reaction liquid over the entire width of the printing medium MD without moving in the main scanning direction, but are not limited to this. The first to fifth print heads may also be so-called serial print heads that eject ink or reaction liquid while moving in the main scanning direction.

[0113] In each of the embodiments described above, the image printing unit 107 is equipped with second to fifth print heads 202 to 205 corresponding to four types (four colors) of ink, but is not limited to this. For example, the image printing unit may be equipped with second to fourth print heads corresponding to three types of ink, or with second to sixth print heads corresponding to five types of ink. In this way, the image printing unit can be equipped with multiple print heads corresponding to multiple types of ink.

[0114] <<Other Embodiments>> The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0115] The disclosure of this embodiment includes configurations represented by the following examples of printing apparatus, image processing methods, and programs.

[0116] <Configuration 1> An image printing unit that applies a reaction solution that reacts with the ink to an ink containing a colorant, and prints an evaluation image onto the print medium to be evaluated. A unit for determining the amount of reaction solution to be applied to the printing medium to be evaluated, based on the evaluation image on the printing medium to be evaluated, Equipped with, The aforementioned evaluation image is Multiple color development evaluation patch images for evaluating the color development of inks with different amounts of reaction solution applied, Includes multiple patch images for evaluating ink bleeding, where the amount of reaction solution applied differs from one another. The printing apparatus is characterized in that the amount of reaction solution to be applied to the printing medium to be evaluated is determined by the application amount determination unit based on the relationship between a plurality of color development evaluation values ​​calculated based on the plurality of color development evaluation patch images and a plurality of bleeding evaluation values ​​calculated based on the plurality of bleeding evaluation patch images.

[0117] <Configuration 2> The printing apparatus according to configuration 1, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated, whichever is larger of the amount of reaction solution to be applied determined based on the plurality of color development evaluation values ​​and the amount of reaction solution to be applied determined based on the plurality of bleeding evaluation values.

[0118] <Structure 3> The printing apparatus according to configuration 2, wherein the evaluation values ​​of the multiple color developments are compared with a threshold, and the amount of reaction solution to be applied based on the evaluation values ​​of the multiple color developments that exceed the threshold is determined.

[0119] <Structure 4> The printing apparatus according to configuration 2 or 3, wherein the evaluation values ​​of the plurality of bleedings are compared with a threshold, and the amount of reaction solution to be applied based on the evaluation values ​​of the plurality of bleedings that do not exceed the threshold is determined.

[0120] <Composition 5> The printing apparatus according to configuration 1, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the multiple color development evaluation values, if the color development evaluation value improves with increasing amount of reaction solution applied.

[0121] <Composition 6> The printing apparatus according to configuration 5, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the multiple bleeding evaluation values ​​if the evaluation value of the color development does not improve with increasing the amount of reaction solution applied in the multiple color development evaluation values.

[0122] <Composition 7> The printing apparatus according to configuration 1, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the multiple evaluation values ​​of bleeding, if the evaluation value of bleeding improves with increasing amount of reaction solution applied.

[0123] <Structure 8> The printing apparatus according to configuration 7, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the multiple color development evaluation values ​​if the bleeding evaluation value does not improve with increasing the amount of reaction solution applied in the multiple bleeding evaluation values.

[0124] <Composition 9> The system further includes an image reading unit that reads the evaluation image on the print medium to be evaluated, The printing apparatus according to any one of configurations 1 to 8, wherein the amount to be applied determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the evaluation image read by the image reading unit.

[0125] <Composition 10> The printing apparatus according to configuration 9, wherein each of the plurality of color evaluation patch images read by the image reading unit includes a solid pattern in which at least one type of ink covers the printing medium to be evaluated.

[0126] <Composition 11> The printing apparatus according to configuration 9 or 10, wherein each of the plurality of patch images for evaluating bleeding read by the image reading unit includes a pattern in which at least one type of ink covers the printing medium to be evaluated and at least one type of ink does not cover the printing medium to be evaluated.

[0127] <Composition 12> The aforementioned multiple color evaluation values ​​are calculated based on the density of the multiple color evaluation patch images read by the image reading unit. The printing apparatus according to any one of the configurations 9 to 11, wherein the evaluation values ​​of the plurality of blurrings are calculated based on the density of the plurality of blurring evaluation patch images read by the image reading unit.

[0128] <Composition 13> The aforementioned multiple color evaluation patch images are arranged in a single row. The printing apparatus according to any one of configurations 1 to 12, wherein the plurality of patch images for evaluating bleeding are arranged in a row parallel to the plurality of patch images for evaluating color development.

[0129] <Composition 14> The steps include: applying a reaction solution that reacts with the ink to an ink containing a colorant, and obtaining reading data by reading the evaluation image printed on the print medium to be evaluated; The steps include determining the amount of reaction solution to apply to the printing medium to be evaluated based on the reading data, It has, The aforementioned evaluation image is Multiple color development evaluation patch images for evaluating the color development of inks with different amounts of reaction solution applied, Includes multiple patch images for evaluating ink bleeding, where the amount of reaction solution applied differs from one another. An image processing method characterized in that, in the step of determining the amount of reaction solution to be applied to the printing medium to be evaluated, the amount of reaction solution to be applied to the printing medium to be evaluated is determined based on the relationship between a plurality of color development evaluation values ​​calculated based on the plurality of color development evaluation patch images and a plurality of bleeding evaluation values ​​calculated based on the plurality of bleeding evaluation patch images.

[0130] <Composition 15> A program that causes a computer to perform the image processing method described in Configuration 14. [Explanation of Symbols]

[0131] 1. Printing System 107 Image Printing Department 308 Amount Determination Unit

Claims

1. An image printing unit that applies a reaction solution that reacts with the ink to an ink containing a colorant, and prints an evaluation image onto the print medium to be evaluated. A unit for determining the amount of reaction solution to be applied to the printing medium to be evaluated, based on the evaluation image on the printing medium to be evaluated, Equipped with, The aforementioned evaluation image is Multiple color development evaluation patch images for evaluating the color development of inks with different amounts of reaction solution applied, Includes multiple patch images for evaluating ink bleeding, where the amount of reaction solution applied differs from one another. The printing apparatus is characterized in that the amount of reaction solution to be applied to the printing medium to be evaluated is determined by the application amount determination unit based on the relationship between a plurality of color development evaluation values ​​calculated based on the plurality of color development evaluation patch images and a plurality of bleeding evaluation values ​​calculated based on the plurality of bleeding evaluation patch images.

2. The printing apparatus according to claim 1, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated, whichever is larger of the amount of reaction solution to be applied determined based on the plurality of color development evaluation values ​​and the amount of reaction solution to be applied determined based on the plurality of bleeding evaluation values.

3. The printing apparatus according to claim 2, wherein the plurality of color development evaluation values ​​are compared with a threshold, and the amount of reaction solution to be applied based on the plurality of color development evaluation values ​​is determined based on the color development evaluation value that exceeds the threshold.

4. The printing apparatus according to claim 2 or 3, wherein the evaluation values ​​of the plurality of bleedings are compared with a threshold, and the amount of reaction solution to be applied based on the evaluation values ​​of the plurality of bleedings that do not exceed the threshold is determined.

5. The printing apparatus according to claim 1, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the multiple color development evaluation values, if the color development evaluation value improves with increasing amount of reaction solution applied.

6. The printing apparatus according to claim 5, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the plurality of bleeding evaluation values ​​if the evaluation value of the color development does not improve with increasing amount of reaction solution applied in the plurality of color development evaluation values.

7. The printing apparatus according to claim 1, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the plurality of evaluation values ​​of bleeding, if the evaluation value of bleeding improves with increasing amount of reaction solution applied.

8. The printing apparatus according to claim 7, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the multiple color development evaluation values ​​if the evaluation value of bleeding does not improve with increasing amount of reaction solution applied in the multiple bleeding evaluation values.

9. The system further includes an image reading unit that reads the evaluation image on the print medium to be evaluated, The printing apparatus according to claim 1, wherein the amount determination unit determines the amount of reaction solution to be applied to the printing medium to be evaluated based on the evaluation image read by the image reading unit.

10. The printing apparatus according to claim 9, wherein each of the plurality of color evaluation patch images read by the image reading unit includes a solid pattern in which at least one type of ink covers the printing medium to be evaluated.

11. The printing apparatus according to claim 9, wherein each of the plurality of patch images for evaluating bleeding read by the image reading unit includes a pattern in which at least one type of ink covers the printing medium to be evaluated and at least one type of ink does not cover the printing medium to be evaluated.

12. The aforementioned multiple color evaluation values ​​are calculated based on the density of the multiple color evaluation patch images read by the image reading unit. The printing apparatus according to claim 9, wherein the evaluation values ​​of the plurality of bleedings are calculated based on the density of the plurality of bleeding evaluation patch images read by the image reading unit.

13. The aforementioned multiple color evaluation patch images are arranged in a single row. The printing apparatus according to claim 1, wherein the plurality of patch images for evaluating bleeding are arranged in a row parallel to the plurality of patch images for evaluating color development.

14. The steps include: applying a reaction solution that reacts with the ink to an ink containing a colorant, and obtaining reading data by reading the evaluation image printed on the print medium to be evaluated; The steps include determining the amount of reaction solution to apply to the printing medium to be evaluated based on the reading data, It has, The aforementioned evaluation image is Multiple color development evaluation patch images for evaluating the color development of inks with different amounts of reaction solution applied, Includes multiple patch images for evaluating ink bleeding, where the amount of reaction solution applied differs from one another. An image processing method characterized in that, in the step of determining the amount of reaction solution to be applied to the printing medium to be evaluated, the amount of reaction solution to be applied to the printing medium to be evaluated is determined based on the relationship between a plurality of color development evaluation values ​​calculated based on the plurality of color development evaluation patch images and a plurality of bleeding evaluation values ​​calculated based on the plurality of bleeding evaluation patch images.

15. A program for causing a computer to perform the image processing method described in claim 14.

Images