Recording device, recording method, and program

Abstract

To solve the problem that blurring may occur due to an insufficiency of reaction liquid at a boundary section of two regions having different application amounts of color material ink, according to impact displacement in applying the color material ink and the reaction liquid.SOLUTION: An insufficiency of reaction liquid at a boundary section is inhibited by expanding reaction liquid data using a maximum value filter, thereby suppressing occurrences of blurring.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a recording device, a recording method, and a program for recording an image on a recording medium. [Background technology]

[0002] Recording devices are known that record images on a recording medium by applying a recording material such as ink. It is known that in such recording devices, inks containing colorants come into contact with each other on the recording medium and attract each other, resulting in bleeding. To prevent bleeding, a reaction liquid that reacts with the colorants contained in the ink is used. Bringing the ink containing colorants into contact with the reaction liquid on the recording medium causes the colorants contained in the ink to aggregate. However, if more reaction liquid is applied than is necessary to aggregate the colorants, excessive aggregation of the colorants may occur, potentially reducing the gloss of the resulting recording. Therefore, the amount of reaction liquid applied must be appropriately determined, and it is known that the amount of reaction liquid is set based on the amount of colorant ink.

[0003] Patent Document 1 discloses a method of making the area to which the treatment liquid is applied wider than the area to which the color ink is applied. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-083299 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the landing position of at least one of the ink and the reaction liquid is shifted, the amount of reaction liquid, which has the function of aggregating the colorant, may be insufficient relative to the amount of colorant in the ink, and image quality may be reduced due to bleeding. For example, in an image in which a region with a large amount of colorant ink applied per unit area and a region with a small amount are adjacent to each other, if the landing position is shifted and more colorant ink than expected lands in the region with a small amount of reaction liquid applied, the reaction will be insufficient and bleeding will occur.

[0006] In response to such problems, an object of the present invention is to provide a recording apparatus that suppresses deterioration in image quality due to bleeding caused by misalignment of the landing positions of ink containing coloring material and reaction liquid. [Means for solving the problem]

[0007] The present invention is characterized by comprising a recording means for recording an image on a recording medium by applying ink containing a colorant and a reaction liquid containing a component that aggregates the colorant; an acquisition means for acquiring multi-value ink data for applying the ink; and a generation means for generating first multi-value reaction liquid data based on the multi-value ink data, and, if the gradation value of a pixel of interest in the first multi-value reaction liquid data is lower than the gradation value of any of a plurality of surrounding pixels around the pixel of interest, changing the gradation value of the pixel of interest to a larger value, thereby generating second multi-value reaction liquid data. [Effects of the Invention]

[0008] The present invention can suppress deterioration in image quality due to bleeding caused by misalignment of the landing positions of ink containing coloring material and reaction liquid. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing the problem that the invention is trying to solve. [Figure 2] FIG. 1 is a perspective view of a recording apparatus according to a first embodiment. [Figure 3] FIG. 2 is a schematic diagram of a heating unit of the recording apparatus according to the first embodiment. [Figure 4] FIG. 2 is a schematic diagram of a recording head according to the first embodiment. [Figure 5] FIG. 2 is a schematic diagram showing a recording control system according to the first embodiment. [Figure 6] 4 is a flowchart of image data processing in the first embodiment. [Figure 7] FIG. 1 is a functional block diagram showing a schematic configuration for image data processing of an image processing system according to a first embodiment. [Figure 8] 5A to 5C are diagrams for explaining multi-value expansion filter processing in the first embodiment. [Figure 9] FIG. 4 is a diagram showing an image processing result in the first embodiment. [Figure 10] 10A to 10C are diagrams for explaining multi-value expansion filter processing in the second embodiment. [Figure 11] 10A to 10C are diagrams for explaining multi-value expansion filter processing in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (Configuration of Inkjet Recording Apparatus) 2 is a diagram showing the appearance of an inkjet recording apparatus (hereinafter also referred to as a recording apparatus) according to this embodiment. The recording apparatus of this embodiment is a so-called serial scanning type recording apparatus, and records an image by scanning a recording head in a direction (X direction) that intersects with the transport direction (Y direction) in which a recording medium P is transported.

[0012] The configuration of the inkjet recording apparatus of this embodiment and an outline of the recording operation will be described below. First, a recording medium P is held on a spool 6. A conveying motor (not shown) drives a conveying roller via a gear, and the driving of the conveying roller conveys the recording medium P from the spool 6 in the conveying direction (Y direction).

[0013] At a predetermined transport position, a carriage motor (not shown) drives the carriage unit 2 to perform reciprocating scanning (reciprocating movement) along a guide shaft 8 extending in the X direction. During this scanning process, an image is recorded by ejecting ink droplets from the ejection ports provided in the print head mounted on the carriage unit 2 at timing based on a position signal obtained by an encoder 7. At this time, the image is recorded in an area having a width (hereinafter referred to as the "band width") corresponding to the arrangement range of the multiple ejection ports arranged in the print head. In this embodiment, scanning is performed at a speed of 40 inches per second, and the printing resolution achieved by ejecting ink droplets is 1200 dpi (dots / inch). Then, after the printing medium P is transported, an image is recorded in the area of ​​the next band width by the next printing scan of the carriage unit 2.

[0014] A carriage belt can be used to transmit the driving force from the carriage motor to the carriage unit 2. Alternatively, instead of a carriage belt, other driving methods may be used, such as one that includes a lead screw that is rotationally driven by the carriage motor and extends in the X direction, and an engagement portion that is provided on the carriage unit 2 and engages with a groove in the lead screw.

[0015] The conveyed recording medium P is sandwiched between a paper feed roller and a pinch roller and guided to a recording position on the platen 4. This recording position is the scanning area of ​​the recording head mounted on the carriage unit 2. Normally, the face of the recording head is capped when in a resting state. Therefore, prior to a recording operation, the cap is opened to make the recording head and carriage unit 2 ready for scanning. Then, when data corresponding to one recording scan is accumulated in the buffer, the carriage motor is driven to scan the carriage unit 2, and the recording operation described above is performed.

[0016] A recording element for discharging ink as droplets is provided inside each ejection port of the recording head 9. A flexible wiring board 19 is provided to supply drive pulses for driving the recording elements, head temperature control signals, etc. The other end of the flexible board is connected to a control unit (not shown) equipped with a control circuit such as a CPU for controlling the recording device.

[0017] The UI screen 50 allows the user to input and confirm instructions to stop the recording operation, information about the recording medium P, and the like.

[0018] FIG. 3 is a side view of the recording apparatus main body. A heater 10 supported by a frame (not shown) is disposed in a curing region located downstream in the transport direction (Y direction in the figure) of the position where the recording head 9 mounted on the carriage unit 2 reciprocates. The heat from the heater 10 dries the liquid ink applied to the recording medium P. The heater 10 is covered by a heater cover 11, which efficiently irradiates the recording medium P with heat from the heater 10 and protects the heater 10. The heater 10 is, for example, a sheath heater or a halogen heater. The heating temperature of the heating unit in the curing region is preferably set taking into consideration the film-forming properties and productivity of the water-soluble resin microparticles and the heat resistance of the recording medium P. The heating unit in the curing region may be heated by blowing hot air from above or by a contact-type heat conduction heater from below the recording medium. In addition, in this embodiment, the heating unit in the curing region has one heating means, but two or more may be provided and used in combination as long as the temperature measured by a radiation thermometer (not shown) on the recording medium P does not exceed the set value of the heating temperature. The recording medium P on which an image has been recorded by applying ink from the recording head 9 is taken up by the take-up spool 12 and becomes a roll-shaped taken-up medium 13.

[0019] (Recording head configuration) 4 is a diagram showing a print head 9 according to this embodiment. The print head 9 has multiple nozzle arrays, each of which has a plurality of nozzles that eject ink containing a colorant. The print head 9 of this embodiment has a nozzle array 22K that ejects black ink (K), a nozzle array 22C that ejects cyan ink (C), a nozzle array 22M that ejects magenta ink (M), and a nozzle array 22Y that ejects yellow ink (Y). Each of the black ink (K), cyan ink (C), magenta ink (M), and yellow ink (Y) contains a colorant, and for simplicity in the following description, these inks will also be referred to as colorant inks.

[0020] The print head 9 of this embodiment also includes an ejection port array 22RCT that ejects a reaction liquid (RCT). This reaction liquid contains a reactive component that reacts with the colorant contained in the colorant ink. When the colorant ink comes into contact with the reaction liquid on the print medium, the components of the reaction liquid aggregate the colorant in the colorant ink, thereby suppressing bleeding. The reaction liquid of this embodiment does not contain a colorant.

[0021] As shown in the figure, the print head 9 is arranged with ejection opening arrays 22K, 22C, 22M, 22Y, and 22RCT in this order. In these ejection opening arrays 22K, 22C, 22M, 22Y, and 22RCT, 1,280 ejection openings 30 that eject the respective inks are arranged in the Y direction (arrangement direction) at a density of 1,200 dpi. In this embodiment, the amount of ink ejected from one ejection opening 30 at one time is approximately 4.5 pl.

[0022] These ejection orifice arrays are connected to ink tanks (not shown) that store the corresponding inks, and ink is supplied from each ink tank. The print head 9 and ink tanks may be integrally configured, or may be separable. The detailed compositions of the black ink (K), cyan ink (C), magenta ink (M), yellow ink (Y), and reaction liquid ink (RCT) will be described later.

[0023] Each color ink may contain water-soluble resin particles that form a film upon heating and improve the scratch resistance of the printed matter. Furthermore, the recording head 9 may be configured to be capable of ejecting a clear emulsion ink (Em) that does not contain a color ink but contains water-soluble resin particles, as an ink different from the color ink and the reaction liquid ink. In this case, the recording head 9 is provided with an ejection port array 22Em that ejects the clear emulsion ink.

[0024] (Ink composition) Next, the details of each ink constituting the ink set of this embodiment will be described. Hereinafter, "parts" and "%" are by weight unless otherwise specified.

[0025] (Composition of each ink) The composition of each ink will be described in detail below.

[0026] The colorant inks (C, M, Y, K) and the reactive liquid ink (RCT) used in this embodiment all contain a water-soluble organic solvent. The water-soluble organic solvent preferably has a boiling point of 150°C or higher and 300°C or lower for reasons of wettability and moisture retention of the print head 9 face surface. Furthermore, from the viewpoints of film-forming function for resin microparticles and swelling solubility in a print medium on which a resin layer is formed, ketone compounds such as acetone and cyclohexanone, propylene glycol derivatives such as tetraethylene glycol dimethyl ether, and heterocyclic compounds having a lactam structure, such as N-methyl-pyrrolidone and 2-pyrrolidone, are particularly preferred. From the viewpoint of ejection performance, the content of the water-soluble organic solvent is preferably 3 wt% or higher and 30 wt% or lower. Specific examples of water-soluble organic solvents include alkyl alcohols having 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol, and amides such as dimethylformamide and dimethylacetamide. Ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol; or alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; lower alkyl ether acetates such as polyethylene glycol monomethyl ether acetate; glycerin; lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether; polyhydric alcohols such as trimethylolpropane and trimethylolethane; N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. The above-mentioned water-soluble organic solvents can be used alone or in mixtures. It is also preferable to use deionized water as the water.The content of the water-soluble organic solvent in the reaction liquid (RCT) is not particularly limited, but in order to give the colorant inks (C, M, Y, K) desired physical properties as needed, surfactants, antifoaming agents, preservatives, antifungal agents, etc. can be added as appropriate in addition to the above-mentioned components.

[0027] In addition, the colorant inks (C, M, Y, K) and the reaction liquid (RCT) used in this embodiment all contain surfactants. Surfactants are used as penetrants to improve the ink's permeability to inkjet recording media. The greater the amount of surfactant added, the stronger the ink's surface tension reduction effect, improving the ink's wettability and permeability to the recording media. In this embodiment, a small amount of acetylene glycol EO adduct or the like was added as a surfactant to adjust the surface tension of each ink to 30 dyn / cm or less, and the difference in surface tension between the inks to within 2 dyn / cm. More specifically, the surface tension of each ink was adjusted to approximately 22 to 24 dyn / cm. A fully automatic surface tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the surface tension. Note that the measuring device is not limited to the above examples, as long as it is capable of measuring the surface tension of the ink.

[0028] Furthermore, the pH of each ink of this embodiment is stable on the alkaline side, with values ​​ranging from 8.5 to 9.5. From the viewpoint of preventing elution and deterioration of components in the recording device or recording head that come into contact with each ink, and a decrease in the solubility of the dispersion resin in the ink, it is preferable that the pH of each ink be between 7.0 and 10.0. pH was measured using a pH meter model F-52 manufactured by Horiba, Ltd. Note that the measuring device is not limited to the above examples, as long as it can measure the pH of the ink.

[0029] Furthermore, the color ink may further include white ink (W) and metallic ink (Mt).

[0030] (Reaction solution) As mentioned above, the reaction liquid contains a reactive component that insolubilizes some or all of the solid components of the colorant ink to prevent bleeding and other problems. The purpose is to insolubilize the dyes dissolved in the colorant ink or the pigments and resins dispersed therein. Examples of reaction liquids include solutions containing polyvalent metal ions (e.g., magnesium nitrate, magnesium chloride, aluminum sulfate, iron chloride, etc.). One type of cationic flocculation method is a system that uses a low-molecular-weight cationic polymer flocculant to neutralize the charge of water-soluble resin particles and insolubilize anionic soluble substances.

[0031] Another reaction system is an insolubilization system using a reaction solution that utilizes a pH difference. As mentioned above, most color inks used in inkjet recording are stable on the alkaline side due to the properties of the color inks themselves. The pH is generally around 7 to 10, but in many cases it is set around 8.5 to 9.5 from an industrial perspective and considering the influence of the external environment. To aggregate and solidify such color inks, an acidic solution is added and the pH is changed, destroying the stable state and causing the dispersed components to aggregate. For this purpose, an acidic solution can also be used as a reaction solution.

[0032] (Water-soluble resin fine particles) The colorant ink used in this embodiment contains water-soluble resin microparticles. "Water-soluble resin microparticles" refers to polymer microparticles dispersed in water. Specific examples include acrylic resin microparticles synthesized by emulsion polymerization of monomers such as (meth)acrylic acid alkyl esters or (meth)acrylic acid alkyl amides; styrene-acrylic resin microparticles synthesized by emulsion polymerization of (meth)acrylic acid alkyl esters or (meth)acrylic acid alkyl amides with styrene monomers; polyethylene resin microparticles, polypropylene resin microparticles, polyurethane resin microparticles, and styrene-butadiene resin microparticles. Core-shell resin microparticles, in which the polymer composition of the core and shell of the resin microparticles differ, and resin microparticles obtained by emulsion polymerization around pre-synthesized acrylic microparticles used as seed particles to control particle size, are also acceptable. Furthermore, hybrid resin microparticles, in which different resin microparticles, such as acrylic resin microparticles and urethane resin microparticles, are chemically bonded, are also acceptable. The water-soluble resin microparticles do not necessarily need to be contained in the colorant ink; they may also be contained in the clear emulsion ink (Em).

[0033] (Recording medium) The recording device in this embodiment records on a low-permeability recording medium that is difficult for water to penetrate. As mentioned above, a low-permeability recording medium refers to a medium that has no or very little water absorption. Therefore, aqueous inks that do not contain organic solvents are repelled, making it impossible to form images. On the other hand, the medium has excellent water resistance and weather resistance, making it suitable for forming printed materials for outdoor use. Typically, a recording medium with a water contact angle of 45° or more, preferably 60° or more, at 25°C is used.

[0034] Low-permeability recording media include recording media with a plastic layer formed on the outermost surface of a substrate, recording media without an ink-receiving layer formed on a substrate, and sheets, films, banners, etc. of glass, Yupo, plastic, etc. Examples of the coated plastics include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc. These low-permeability recording media have excellent water resistance, light resistance, and abrasion resistance, and are therefore generally used when recording materials for outdoor exhibition.

[0035] One example of a method for evaluating the permeability of a recording medium is the Bristow method described in JAPAN TAPPI Paper and Pulp Test Method No. 51, "Test Method for Liquid Absorbency of Paper and Paperboard." In the Bristow method, a predetermined amount of ink is poured into a holding container with a predetermined-sized opening slit, and the ink is brought into contact with a recording medium that has been processed into a strip and wrapped around a disk. The disk is rotated while the position of the holding container is fixed, and the area (length) of the ink band transferred to the recording medium is measured. From the area of ​​this ink band, the amount of ink transferred per unit area per second (ml m-2) can be calculated. In this embodiment, a recording medium with an ink transfer amount (water absorption amount) of less than 10 ml m-2 in 30 msec1 / 2 using the Bristow method is considered to have low permeability.

[0036] (Bleeding at the boundary between areas with different duties) Here, as a comparative example, we will explain the issues that arise when applying a conventional printing control method. FIG. 1(a) shows input image data, with the left half of the image showing a 100% black (K) ink application amount per unit area, and the right half showing a 50% black (K) ink application amount per unit surface area. Here, the application amount per unit area is referred to as duty, and in this embodiment, 100% duty is assumed when four dots are applied to one pixel of 600 dpi x 600 dpi. FIG. 1(b) shows reaction liquid data generated based on the K ink data of FIG. 1(a). The generated reaction liquid data indicates that 50% reaction liquid is applied to an area where the K ink duty is 100%, and 25% reaction liquid is applied to an area where the K ink duty is 50%. FIG. 1(c) shows the multi-value expanded reaction liquid data, and FIG. 1(d) shows the K ink data and reaction liquid data superimposed on each other. As shown in Figure 1(c), by expanding the area where the reaction liquid is applied so that it is wider than the area where the colorant ink is applied, it is possible to suppress bleeding at the edge of the area where the colorant ink is applied.

[0037] Here, we found that when applying colorant ink and reaction liquid, as shown in Figure 1(d), if there is a landing misalignment of at least one of the colorant ink and reaction liquid, bleeding occurs at the boundary between two regions with different colorant ink duties. Figure 1(e) shows a diagram illustrating a case where the landing position of the colorant ink is misaligned, and Figure 1(f) is an enlarged view of this boundary. Normally, a 50% duty of reaction liquid is required for region X1, where the K ink duty is 100%, but the duty of the reaction liquid is 50% in region X3 and 25% in region X4. Therefore, in region X1, the amount of reaction liquid is insufficient compared to the amount of colorant ink, resulting in bleeding of the colorant ink. In this way, if there is a landing misalignment such that a region with a large amount of colorant ink extends into a region with a small amount of reaction liquid, bleeding may occur at the boundary between regions with different colorant ink duties.

[0038] In contrast, in this embodiment, bleeding at the boundary between two areas with different color ink duties is suppressed by changing the amount of reaction liquid data applied based on the color ink data. A specific method for this will be described later using FIG.

[0039] (Recording system configuration) 5 is a block diagram showing a schematic configuration of a control system within the printing apparatus 100 of this embodiment. The main control unit 300 includes a CPU 301 that performs processing operations such as calculation, selection, discrimination, and control, as well as printing operations; a ROM 302 that stores control programs to be executed by the CPU 301; a RAM 303 used as a print data buffer; and an input / output port 304. A memory 313 stores mask patterns, which will be described later. The input / output port 304 is connected to drive circuits 305, 306, 307, and 308 for a transport motor (LF motor) 309, a carriage motor (CR motor) 310, the print head 9, the heater 10, and actuators in the cutting unit. Furthermore, the main control unit 300 is connected to a host PC 312 via an interface circuit 311.

[0040] (Image processing flow) Fig. 6 is a flowchart for explaining image processing. Below, a process for generating ejection data for image recording in the recording device from input image data will be explained using Fig. 5 and Fig. 6. This process is performed by either the host device 312 or the recording device 100, and a part of the process may be shared and performed by both.

[0041] The host device 312 is, for example, a personal computer (PC). The host device 312 includes an application (not shown) and a printer driver (not shown) for the recording device 100. The application executes a process for creating recording image data to be sent to the printer driver based on information specified by the user on the UI screen of the host device 312, and a process for setting recording control information that governs recording control.

[0042] The print image data and print control information processed by the application are sent to the printer driver at the time of printing. The print image data is then transferred from the host device 312, in which the printer driver is installed, to the printing device 100 via the interface circuit 311. The main control unit 300 of the printing device 100 performs image processing on the transferred print image data.

[0043] The following program is stored in the memory 313 built into the main control unit 300 of the printing apparatus 100 and executed by the CPU 301. In step S601 shown in FIG. 6, input image data is acquired and stored in a storage unit such as a memory included in the printing apparatus. In step S602, a color separation process is performed in an image processing configuration described below to generate multi-value ink data of the color ink colors (CMYK) used for printing and multi-value reaction liquid data. In step S603, a conversion process, which is a characteristic configuration of this embodiment, is performed using a multi-value expansion filter to replace the gradation value of each pixel of the multi-value reaction liquid data with the maximum value of the gradation values ​​of the surrounding pixels. This conversion process using the multi-value expansion filter will be described later with reference to FIG. 8. In steps S604 and S605, a quantization process is performed to quantize the CMYK multi-value ink data after the color separation process and the multi-value reaction liquid data after the multi-value expansion process. An image is then printed based on the quantized data obtained in steps S604 and S605.

[0044] FIG. 7 is a diagram illustrating an image processing unit that processes print image data and converts it into print head ejection data based on the image processing flow described in the flowchart of FIG. 6. Image data to be printed is input to an input unit 71. The image data is input in the form of 8 bits for each RGB, for a total of 24 bits. The ink color conversion unit 72 converts the RGB data into 8 bits for each CMYK, which are the colorant ink colors of the inkjet printing device of the present invention, for a total of 32 bits for the four colors, and 8 bits of reaction liquid data. These 8-bit values ​​for each CMYK and 8-bit values ​​for reaction liquid represent the amount of each colorant ink color and reaction liquid. That is, for the 8-bit values ​​for each CMYK color and 8-bit values ​​for reaction liquid, values ​​from 0 to 255 range from 0 to 255, where 0 represents 0% colorant ink and reaction liquid volume, 255 represents 100% colorant ink and reaction liquid volume, and intermediate values ​​between 0 and 255 represent proportional amounts of colorant ink and reaction liquid. In this embodiment, the expansion filter processing unit 73 functions as a square maximum value filter. This maximum value filter replaces the gradation value (0-255) of the target pixel in the 8-bit reaction liquid data with the maximum gradation value (0-255) of the pixels within a square area centered on the target pixel. The range of the maximum value filter is set to an arbitrary size depending on the impact variation between the color ink and the reaction liquid. By applying the maximum value filter to all pixels in the reaction liquid data, the high-duty area is expanded, and the gradation values ​​of pixels on the boundary with the low-duty area are replaced with higher gradation values. The quantization unit 74 converts the 8-bit CMYK data converted in step S602 and the 8-bit reaction liquid data expanded by the expansion filter processing unit 73 into binary or multi-value data indicating whether ink is being ejected (or not ejected) from the print head. In this embodiment, dithering is used as the quantization process used by the quantization unit 74, but this is not limited to dithering and may also be error diffusion processing, etc. The recording unit 75 records an image on a recording medium by controlling the ejection of ink from the recording head based on the CMYK data and reaction liquid data converted into binary or multi-value data by quantization processing in the quantization unit 74. In this diagram, the CMYK and reaction liquid data quantized in the quantization unit 74 is 1-bit data per pixel, but it may also be 2-bit or more data.

[0045] (Multi-value expansion filter processing method) FIG. 8 is a diagram illustrating the multi-value expansion filter used in step S603. In this embodiment, the multi-value expansion filter is implemented as a function of an application specific integrated circuit (abbreviated as ASIC). The multi-value expansion filter applies a 5×5 pixel maximum value filter shown in FIG. 8(a) to the pixel of interest (i,j). Then, the value of the pixel of interest (i,j) is updated to the maximum value of the gradation values ​​of the 25 pixels of the 5×5 pixels centered around the pixel of interest. If the 8-bit value of the pixel of interest (i,j) is f(i,j), the maximum value of the 8-bit values ​​of the surrounding pixels (i+m,j+n) is Max(i+m,j+n), and the output value of the pixel of interest (i,j) is g(i,j), then If Max(i+m,j+n)>f(i,j), g(i,j)=Max(i+m,j+n)...(Formula 1) On the other hand, if Max(i+m,j+n)≦f(i,j), g(i,j)=f(i,j)...(Formula 2) Here, m and n are integers that satisfy the conditions -2≦m, n≦2.

[0046] 8(b) is a schematic diagram showing an image of multi-value ink data for color ink, in which an area 801 where the color ink application amount is 100% is adjacent to an area 802 where the color ink application amount is 50%. One pixel is 8-bit data, and the gradation value of a pixel with a duty of 100% is 255, and the gradation value of a pixel with a duty of 50% is 128. A pixel with a gradation value of 0 has a color ink application amount of 0%.

[0047] FIG. 8(c) shows multi-value reaction liquid data generated based on the colorant ink data of FIG. 8(b). For region 801 where the colorant ink application amount is 100%, the gradation value in the reaction liquid data is 64, and for region 802 where the colorant ink application amount is 50%, the gradation value in the reaction liquid data is 32. In other words, the multi-value reaction liquid data is generated so that the gradation value is lower than the gradation value of each pixel in the colorant ink data. Therefore, the amount of reaction liquid applied is less than the amount of colorant ink applied. As with the colorant ink data, a pixel with a gradation value of 0 has 0% reaction liquid applied.

[0048] Figure 8(d) shows the results of applying the 5 x 5 pixel maximum value filter shown in Figure 8(a) to all of the pixels shown in Figure 8(c) in accordance with the conditions described above. Region 805 is made up of pixels with a gradation value of 64, and region 806 is made up of pixels with a gradation value of 32. Compared to the reaction liquid data in Figure 8(c), in the reaction liquid data in Figure 8(d), the pixels with a gradation value of 64 have expanded by two pixels vertically and horizontally, and the boundary pixels that had a gradation value of 32 in Figure 8(c) have been changed to 64. As a result, in region 802 in the colorant ink data, a larger amount of reaction liquid is applied to the boundary region of two pixels adjacent to region 801 relative to the amount of colorant ink data applied.

[0049] 9A and 9B are diagrams illustrating the effects of applying the configuration of this embodiment. It is assumed that a landing deviation occurs when an image is printed based on the colorant ink data of FIG. 8A and the reaction liquid data of FIG. 8D. FIG. 9A shows a state in which an area where a large amount of reaction liquid is applied is expanded. Even if a landing deviation occurs between the colorant ink and the reaction liquid at the boundary between two areas where different amounts of colorant ink are applied, as shown in FIG. 9B, an area X3' where the amount of reaction liquid applied is 50% overlaps with an area X1' where the amount of colorant ink applied is 100%.

[0050] In this manner, in this embodiment, a maximum value filter is used on the reaction liquid data, and the value of the pixel of interest is changed to the maximum value of the surrounding pixels adjacent to the pixel of interest, thereby expanding the pixel value of the reaction liquid data. As a result, even if the ink impact position is shifted, bleeding due to a lack of reaction liquid can be suppressed at the boundary between two areas with different color ink duties.

[0051] In this embodiment, the maximum value filter has a shape of 5x5 pixels, and the 24 pixels surrounding the pixel of interest are considered to be adjacent pixels. However, the present invention is not limited to this; the shape may be square, and the size of the filter is not important. For example, the size of the filter may be changed depending on the type of recording medium. For recording media with a surface that easily bleeds or recording media with a thin paper thickness and a large distance from the recording head, the impact deviation between the colorant ink and the reaction liquid tends to be large, so a larger filter is used. The size of the filter may also be changed depending on the scanning speed of the recording head. The faster the scanning speed of the recording head, the larger the impact deviation between the colorant ink and the reaction liquid tends to be.

[0052] In this embodiment, among the regions where the amount of color ink applied is relatively small, the amount of reaction liquid applied to the boundary region adjacent to the region where the amount of color ink applied is relatively large is made larger than that to the internal region that is not adjacent to the boundary region. In the example described above, the amount of reaction liquid applied to the region where the amount of color ink applied is large is made the same as that to the region where the amount of color ink applied is large, but it does not have to be exactly the same amount.

[0053] The size of the filter may also be changed depending on the transport speed of the recording medium. In the case of a recording device that ejects the color ink and the reaction liquid simultaneously while the recording medium is transported, the larger the filter used, since the faster the recording medium transport speed, the greater the deviation in landing positions between the color ink and the reaction liquid tends to be. The size of the filter may also be changed depending on the distance between the recording head and the recording medium. The larger the distance between the recording head and the recording medium, the greater the deviation in landing positions between the color ink and the reaction liquid tends to be, so the larger the filter used. The size of the filter may also be changed depending on the recording mode. In the case of a recording mode in which the deviation in landing positions between the color ink and the reaction liquid is greater, the larger the filter used.

[0054] (Second embodiment) In the above-described embodiment, the multi-value dilation filter used in step S603 is square, and the amount of expansion of the reaction liquid from the high-duty region to the low-duty region is the same amount, two pixels vertically and horizontally. On the other hand, in a so-called serial scanning printing device that prints an image by scanning the print head in a direction perpendicular to the direction in which the print medium P is transported, the amount of impact deviation tends to be greater in the scanning direction of the print head than in the transport direction. Therefore, it is necessary to reduce the amount of reaction liquid applied in the transport direction while further reducing bleeding in the scanning direction, thereby reducing the adverse effects of applying too much reaction liquid, such as reduced gloss. In this embodiment, this problem is solved by reducing the amount of expansion in the transport direction compared to the amount of expansion in the scanning direction.

[0055] The multi-value expansion filter method according to this embodiment will be described in detail with reference to Fig. 10. The multi-value ink data of the color inks in Fig. 8(b) and the multi-value reaction liquid data in Fig. 8(c) generated based on the multi-value ink data in Fig. 8(b) are the same as those in the first embodiment.

[0056] In the multi-value reaction liquid data of FIG. 8(c), a 5×3 pixel maximum value filter shown in FIG. 10(a) is applied as a multi-value expansion filter to the pixel of interest (i,j). Then, the value of the pixel of interest (i,j) is updated to the maximum value among the 15 pixels of the 5×3 pixels. If the 8-bit value of the pixel of interest (i,j) is f(i,j), the maximum value among the 8-bit values ​​of the surrounding pixels (i+m,j+n) is Max(i+m,j+n), and the output value of the pixel of interest (i,j) is g(i,j), then If Max(i+m,j+n)>f(i,j), g(i,j)=Max(i+m,j+n)...(Formula 3) On the other hand, if Max(i+m,j+n)≦f(i,j), g(i,j)=f(i,j)...(Equation 4) This becomes:

[0057] Here, m and n are integers that satisfy −1≦m≦1 and −2≦n≦2.

[0058] Fig. 10(b) shows the reaction liquid data after expansion processing, obtained by applying the maximum value filter of Fig. 10(a) to the multi-value reaction liquid data of Fig. 8(c). By applying the 5x3 maximum value filter shown in Fig. 10(a) according to the conditions described above, the pixel with a reaction liquid gradation value of 64 is expanded by one pixel vertically and two pixels horizontally, as shown in Fig. 10(b).

[0059] The shape of the maximum value filter may be longer in the transport direction than in the scanning direction. For example, the shape of the maximum value filter may be 3 × 5 pixels. According to this embodiment, by reducing the amount of expansion of the reaction liquid in a direction in which landing deviation is less likely to occur compared to a direction in which landing deviation is more likely to occur, it is possible to suppress bleeding due to a shortage of reaction liquid caused by landing deviation, while also suppressing degradation of image quality, such as reduced gloss, due to the application of too much reaction liquid.

[0060] (Third embodiment) In the above-described embodiment, the multi-value expansion filter applied a maximum value filter to the pixel of interest (i, j), updating the value of the pixel of interest (i, j) with the maximum value of the pixels in the filter. However, if the boundary between the expanded and non-expanded portions becomes noticeable due to the difference in the amount of reaction liquid when the reaction liquid application area is expanded, it is preferable to minimize the difference in the amount of reaction liquid between the expanded and non-expanded portions. At the same time, it is also necessary to minimize the amount of reaction liquid applied in order to suppress a decrease in gloss. Therefore, in this embodiment, we aim to solve this problem by increasing the amount of reaction liquid in the expanded portion compared to before expansion, while reducing it below the maximum amount of reaction liquid in the surrounding pixels.

[0061] Fig. 11 is a diagram for explaining the multi-value expansion filter used in this embodiment. The multi-value ink data of the color ink in Fig. 8(b) and the multi-value reaction liquid data in Fig. 8(c) generated based on the multi-value ink data in Fig. 8(b) are the same as those in the first embodiment.

[0062] A multi-value expansion filter of 5x5 pixels size shown in Figure 11(a) is applied to the multi-value reaction liquid data of Figure 8(c). As a result, the value of the pixel of interest (i,j) is updated to a value smaller than the maximum value of the gradation values ​​of the 5x5 pixels. If the 8-bit value of the pixel of interest (i,j) is f(i,j), the maximum value of the 8-bit values ​​of the surrounding pixels (i+m,j+n) is Max(i+m,j+n), and the output value of the pixel of interest (i,j) is g(i,j), then for example, Max(i+m,j+n)>f(i,j) and If Max(i+m,j+n)-f(i,j)>32 g(i,j)=3 / 4×(Max(i+m,j+n)-f(i,j))+f(i,j)...(Equation 5) Here, g(i,j) is an integer, and if the calculation result is a decimal, it is rounded up. Max(i+m,j+n)>f(i,j) and If Max(i+m,j+n)-f(i,j)≦32 g(i,j)=1 / 2×(Max(i+m,j+n)-f(i,j))+f(i,j)...(Equation 6) Here, g(i,j) is an integer, and if the calculation result is a decimal, it is rounded up.

[0063] on the other hand, If Max(i+m,j+n)≦f(i,j), g(i,j)=f(i,j)...(Equation 7) Here, m and n are integers that satisfy the conditions -2≦m, n≦2.

[0064] Applying the 5x5 filter shown in Figure 11(a) to all pixels of the reaction liquid data shown in Figure 8(c) under the above conditions yields the output values ​​of the reaction liquid data shown in Figure 11(b). Region 1111, where the amount of reaction liquid applied is 64, expands by two pixels to region 1112, where the amount of reaction liquid is 32, resulting in region 1121, where g(i,j) = 58. Region 1113, where the amount of reaction liquid is 0, expands by two pixels vertically and horizontally to region 1122, where g(i,j) = 48. Region 1112, where the amount of reaction liquid is 32, expands by two pixels vertically and horizontally to region 1113, where the amount of reaction liquid is 0, resulting in region 1123, where g(i,j) = 16.

[0065] In addition, Max(i+m,j+n)>f(i,j) and When Max(i+m,j+n)-f(i,j)>32, it is not limited to (Equation 5), Max(i+m,j+n)>g(i,j)>3 / 4×(Max(i+m,j+n)-f(i,j))+f(i,j)...(Formula 8) It is sufficient to satisfy the above.

[0066] Also, Max(i+m,j+n)>f(i,j) and In the case where Max(i+m,j+n)-f(i,j)≦32, it is not limited to (Equation 6), Max(i+m,j+n)>g(i,j)>1 / 2×(Max(i+m,j+n)-f(i,j))+f(i,j) (Equation 9) It is sufficient to satisfy the above.

[0067] Here, the conditions for the output value g(i,j) are expressed by the above (Equation 8) and (Equation 9), but this is not limited to this and any equation can be used as long as it satisfies Max(i+m,j+n)>g(i,j). Also, here there are two conditional equations, but this is not limited to this and one, three, or more equations are also acceptable.

[0068] According to this embodiment, the difference in the amount of reaction liquid between the expanded and non-expanded portions of the reaction liquid portion is reduced, making it possible to make the boundary between the expanded and non-expanded portions less noticeable and also to suppress a decrease in gloss.

[0069] (Other embodiments) In the above-described embodiment, a filter is used in the multi-value expansion process, but this is not limiting and a filter may not be used. For example, there is a method of detecting an area where there is a difference in gradation and multiplying the multi-value data at the boundary by a coefficient to increase the value. Another method is to use a method known as multi-value morphological conversion processing to expand the area by adding multi-value pixels to the boundary.

[0070] In the above embodiment, the maximum value of the area corresponding to the filter size is used, but it does not necessarily have to be the maximum value. It is sufficient if the grayscale value can be changed to a value greater than the grayscale value of the pixel of interest in the expansion process.

[0071] Furthermore, in the above embodiment, the reaction liquid data for applying the reaction liquid has been described, but the above configuration can also be applied to clear emulsion ink (Em) used for the purpose of improving glossiness.

[0072] Furthermore, in the above-described embodiment, the recording device is a serial scanning type, but this is not limited to this, and it may be, for example, a so-called line head type recording device that records an image by scanning the recording medium P with a fixed recording head. [Explanation of symbols]

[0073] 2 Carriage Unit 9. Recording head 30 outlet 100 Recording device 312 Host PC

Claims

1. a recording means for recording an image on a recording medium by applying an ink containing a coloring material and a reaction liquid containing a component that aggregates the coloring material; an acquisition means for acquiring multi-value ink data for applying ink; a generating means for generating first multi-value reaction liquid data based on the multi-value ink data, and for generating second multi-value reaction liquid data by changing the gradation value of a pixel of interest to a larger value when the gradation value of the pixel of interest in the first multi-value reaction liquid data is lower than the gradation value of any of a plurality of surrounding pixels around the pixel of interest; A recording device comprising:

2. The recording device according to claim 1, characterized in that the generating means generates the second multi-value reaction liquid data by changing the gradation value of the pixel of interest in the first multi-value reaction liquid data so that it becomes the maximum value among the gradation values ​​of the plurality of surrounding pixels.

3. 3. The recording apparatus according to claim 1, wherein the generating means generates second multi-value reaction liquid data by using a filter on the first multi-value reaction liquid data.

4. 4. The recording apparatus according to claim 1, wherein the gradation value of each pixel of the first multi-value reaction liquid data is lower than the gradation value of the multi-value ink data.

5. 5. The printing apparatus according to claim 1, further comprising a quantization unit that generates quantized data indicating whether or not ink and reaction liquid are applied from the printing unit by quantizing the multi-value ink data and the multi-value reaction liquid data.

6. 6. The recording apparatus according to claim 5, further comprising control means for controlling a recording operation of said recording means based on said quantized data to record an image on a recording medium.

7. A recording method for an apparatus having a recording means for recording an image on a recording medium by applying ink containing a coloring material and a reaction liquid containing a component that aggregates the coloring material, the method comprising: an acquisition step of acquiring multi-value ink data for applying ink; a generating step of generating first multi-value reaction liquid data based on the multi-value ink data, and when the gradation value of a pixel of interest in the first multi-value reaction liquid data is lower than the gradation value of any of a plurality of surrounding pixels around the pixel of interest, changing the gradation value of the pixel of interest to a larger value, thereby generating second multi-value reaction liquid data; a control step of controlling a recording operation for recording an image based on the multi-value ink data and the second multi-value reaction liquid data; A recording method comprising:

8. A program for causing a computer to execute each step of the recording method according to claim 7.

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