Inkjet printing apparatus and printing method

Abstract

To record an image of high quality.SOLUTION: An ink jet printing apparatus configured to print an image on a printing medium includes a printing unit including a first ejection portion configured to eject an ink containing resin fine particles and a coloring material, and a second ejection portion configured to eject a reaction liquid that reacts with the resin fine particles and the coloring material in the ink to cause aggregation or gelation, and a determination unit configured to determine an application amount of the reaction liquid based on an application amount of the ink for each partial region of the printing medium. The second discharger is configured to discharge, as the reaction liquid, at least one of a first reaction liquid having a first composition and a second reaction liquid having a second composition. The determination unit determines the application amounts of the first reaction liquid and the second reaction liquid such that a first ratio, which is a ratio of the application amount of the second reaction liquid to the total application amount of the first reaction liquid and the second reaction liquid in a case where the application amount of the ink is a first application amount, and a second ratio, which is a ratio of the application amount of the second reaction liquid to the total application amount of the first reaction liquid and the second reaction liquid in a case where the application amount of the ink is a second application amount that is greater than the first application amount, are different.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a recording apparatus that forms an image by ejecting ink. [Background technology]

[0002] There is a growing demand for inkjet recording devices using pigment inks to be able to record on polyvinyl chloride sheets (PVC sheets), which are used for coated paper in commercial and publishing printing. One recording method is to eject ink containing coloring material and a reaction liquid onto these recording media, causing the ink to react and agglomerate onto the recording media.

[0003] In recording methods using a reaction liquid, it is common to vary the amount of reaction liquid applied depending on the recording gradation of the ink. For example, in recording areas with low recording gradation, the amount of reaction liquid applied is increased to increase the coverage of the recording medium with the reaction liquid and prevent uneven bonding between the reaction colorants. However, when an organic acid or polyvalent metal salt is used in the reaction liquid, increasing the components of the reaction liquid makes it more likely that the reaction components or polyvalent metal salt will precipitate on the image. Patent Document 1 proposes a technology that suppresses precipitation by using a low-concentration reaction liquid in recording areas with low recording gradation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-155706 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in areas where the recording gradation is high, the precipitates may be visible as cloudy images. It is difficult to sufficiently suppress cloudiness in areas where the recording gradation is high using only the method described in Patent Document 1. On the other hand, although there are reactants that are less likely to cause such precipitation, there are problems in that the ink tends to aggregate, resulting in unevenness on the image recording surface and a decrease in gloss.

[0006] The present invention has been made in view of the above problems, and has as its object to provide a technique that enables high-quality image recording. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, an inkjet recording apparatus according to the present invention has the following configuration: a recording means including a first ejection unit that ejects ink containing resin particles and coloring material, and a second ejection unit that ejects a reaction liquid that reacts with the resin particles and coloring material in the ink to cause aggregation or gelation; a determination unit that determines the amount of the reaction liquid to be applied for each partial area of ​​the recording medium based on the amount of the ink to be applied; Equipped with the second discharge unit is configured to discharge, as the reaction liquid, at least one of a first reaction liquid having a first composition and a second reaction liquid having a second composition different from the first composition; The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that a first ratio, which is the ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a first amount, is different from a second ratio, which is the ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a second amount that is greater than the first amount. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a technique that enables high-quality image recording. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an inkjet recording apparatus. [Figure 2] FIG. 2 is a schematic diagram of a print head viewed from the ejection port side. [Figure 3] FIG. 2 is a schematic diagram showing a recording control system. [Figure 4] 10 is a flowchart showing a process of processing image data. [Figure 5] FIG. 1 is a diagram illustrating general generation of print data. [Figure 6] FIG. 1 is a diagram illustrating a general multi-pass printing method. [Figure 7] FIG. 10 is a diagram showing a table storing the relationship between the amount of ink applied and the amount of reaction liquid applied. [Figure 8] 10 is a flowchart showing a process of processing image data. [Figure 9] FIG. 10 is a diagram showing a table storing the relationship between the amount of ink applied and the amount of reaction liquid applied. [Figure 10] 10 is a flowchart showing a process of processing image data. [Figure 11] FIG. 10 is a diagram showing a table storing the relationship between the amount of ink applied and the amount of reaction liquid applied. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0011] (First embodiment) As a first embodiment of the recording apparatus according to the present invention, a recording apparatus using an inkjet recording method will be described below. The recording apparatus may be, for example, a single-function printer having only a recording function, or may be, for example, a multi-function printer having multiple functions such as a recording function, a fax function, and a scanner function.

[0012] In the following explanation, "recording" means forming images such as characters and figures on a recording medium such as paper. However, the formed image may or may not be visible to humans, and it also broadly refers to forming images, patterns, structures, etc. on a recording medium or processing the medium.

[0013] Furthermore, the term "recording medium" refers not only to paper used in general recording devices, but also to materials capable of receiving ink, such as cloth, plastic film, metal plate, glass, ceramics, resin, wood, and leather. Non-absorbent recording media include, for example, glass, plastic, film, and Yupo, which are not designed as recording media for aqueous inkjet inks. Other examples include substrates such as plastic film and paper that are not surface-treated for inkjet printing (i.e., do not have an ink-absorbing layer), such as substrates coated with plastic. Examples of plastics include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene. Specific examples of low-absorbent recording media include printing paper used in offset printing, such as art paper and coated paper.

[0014] <Device configuration> FIG. 1 shows the configuration of an inkjet recording apparatus 100. FIG. 1(a) is a perspective view partially exploded to explain the internal mechanism, and FIG. 1(b) is a cross-sectional view. As shown in FIG. 1, a recording medium 12 is transported in the -Y direction in the figure as a sub-scanning motor (not shown) is driven. In addition, a guide shaft 13 is disposed so as to extend in the X direction, which intersects with the Y direction, which is the transport direction of the recording medium 12.

[0015] A carriage 11 carrying a recording head 15 disposed opposite the platen 10 is supported by a guide shaft 13 and moves back and forth (scans back and forth) along the X direction by being driven by a main scanning motor (not shown). The recording head 15 mounted on the carriage 11 ejects ink onto a recording medium 12 in accordance with recording data while the carriage 11 is moving and scanning, thereby performing recording on the recording medium 12.

[0016] The inkjet recording apparatus 100 of this embodiment employs a so-called bidirectional recording method in which the recording head 15 ejects ink to record an image on the recording medium both when moving along a forward path and when moving along a backward path. When the recording head 15 performs a single scanning operation involving recording, the recording medium 12 is transported a predetermined distance by a sub-scanning motor (not shown). The main scanning speed is variable, allowing scanning at speeds of 10 to 70 inches per second. The recording resolution is also variable, allowing ejection operations at 300 to 2400 dots per inch (dpi). After the above-described scanning, the recording medium 12 is transported, and the next recording is performed on an area on the recording medium that is shifted by the transport amount.

[0017] When a printing operation command is input from an external device 312 (described later with reference to FIG. 3), the printing medium 12 is fed to a position where printing is possible by the printing head 15 mounted on the carriage 11. An image is then printed by alternately repeating main scanning of the printing head 15 while ejecting ink in response to a printing signal and conveying the printing medium 12 a predetermined distance. The image formed on the printing medium 12 on the platen 10 is then conveyed along the -Y direction, and the heating mechanism 14 applies hot air to the printing medium, heating it to a temperature of 60°C to 120°C, thereby fixing it. The heating mechanism 14 also functions to heat and form a film of water-soluble resin particles (described later) within the printing apparatus. These water-soluble resin particles are applied to the printing medium and then heated to form a film, improving the abrasion resistance of the image. In this embodiment, the temperature setting is adjusted so that the surface of the printing medium is 80°C.

[0018] In this embodiment, the recording head 15, which is the recording unit, is configured to be able to eject color inks (K, C, M, Y) and white ink (W). In addition, it is configured to be able to eject two types of reaction liquids (RCT1, RCT2). The reaction liquid contains a reactant, which reacts with solid components such as coloring materials and resin particles contained in each ink to promote their aggregation. Details of the inks and reaction liquid will be described later.

[0019] FIG. 2 is a detailed schematic diagram of the print head 15 that ejects ink and reaction liquid, showing the configuration of the print head 15 as viewed from the ejection port side. The print head 15 has 1,024 ejection ports 20, each equipped with a printing element, arranged in the Y direction at a density of 1,200 per inch. This arrangement forms an ejection section (ejection port array) for one color. In this embodiment, seven ejection port array forming substrates are mounted. The print head 15 includes ejection sections (ejection port arrays) for two types of reaction liquid: an ejection port array 21R1 for a first reaction liquid (RCT1) and an ejection port array 21R2 for a second reaction liquid (RCT2). The print head 15 also includes ejection port arrays for each color ink: a black (K) ejection port array 21K, a cyan (C) ejection port array 21C, a magenta (M) ejection port array 21M, a yellow (Y) ejection port array 21Y, and a white (W) ejection port array 21W.

[0020] The ejection volume of each ink and reaction liquid ejected from each ejection port 20 is approximately 4.5 pL. However, this is not limited to this; different settings may be used for the ink and reaction liquid, or the ejection volume may be changed for each ink. The print head 15 ejects the ink and reaction liquid from the ejection port 20 using ejection energy generated by printing elements such as electrothermal converters (heaters) and piezoelectric elements. When an electrothermal converter is used, the heat generated by the converter causes water in the ink to bubble, and the resulting bubble energy can be used to eject the ink. Furthermore, these ejection units do not necessarily have to be formed on the same print head; they may be separate units. These ejection units are connected to ink tanks (not shown) that store the corresponding inks, and ink is supplied to them. Note that the print head 15 and ink tanks used in this embodiment may be integrally configured, or may be separable.

[0021] 3 is a schematic diagram showing a recording control system. An image input unit 311 inputs various image data from an external device 312 such as a personal computer (PC). The image data includes, for example, multi-value image data from an image input device such as a scanner or digital camera, and multi-value image data stored on various recording media such as a hard disk. An image processing unit 300 converts the input multi-value image data into binary image data using image processing described below. This binary image data includes image data of color inks (K, C, M, Y), white ink (W), and reaction liquids (RCT1, RCT2).

[0022] A central processing unit (CPU) 301 controls each section of the recording device. A read-only memory (ROM) 302 stores control programs and error processing programs executed by the CPU 301. A random access memory (RAM) 303 temporarily stores various data (image data, recording signals supplied to the recording head, etc.). An input / output port 304 controls an LF motor 309, a CR motor 310, and drive circuits 305 to 308 for driving the recording head 15. The input / output port 304 also controls data transfer between an image input unit 311, the CPU 301, and the RAM 303.

[0023] The LF motor 309 is a motor for transporting the recording medium 12 in the -Y direction (sub-scanning direction), and the CR motor 310 is a motor for moving the recording head 15 in the X direction (main scanning direction). Drive circuits 305 and 306 are motor drivers for driving the LF motor 309 and the CR motor 310, respectively. Drive circuit 307 is a head driver for driving the recording head 15. By driving the LF motor 309 and the CR motor 310 and driving the recording head 15 based on binary recording data generated by an image input unit 311, an image can be recorded on the recording medium 12. The heating mechanism 14 is driven by the drive circuit 308 and heats the recording medium 12.

[0024] <Device Operation> In this embodiment, an image is recorded according to a multi-pass recording method in which an image is recorded in a unit area (partial area) on a recording medium by multiple scans. Here, in each of the multiple scans, droplets (ink and reaction liquid) are discharged according to recording data that determines whether or not to discharge droplets for each of multiple pixels.

[0025] In this embodiment, a dither mask and a pass mask are used to generate print data corresponding to each of multiple scans from image data. A general method for processing image data when printing (forming an image) in 8 passes using a dither mask and a pass mask is described below. For simplicity of explanation, the image data will be described as 8-bit data capable of expressing 256 gradation values ​​from 0 to 255. In addition, both the dither mask and the pass mask are assumed to have a size corresponding to an 8 pixel x 8 pixel area, which is equivalent to a unit area.

[0026] FIG. 5 is a diagram illustrating general print data generation. Specifically, it illustrates a method for generating print data by processing the image data described above. FIG. 5(a) is a diagram illustrating an example of a dither mask. FIG. 5(b) is a diagram illustrating binary data generated by applying the dither mask shown in FIG. 5(a) to image data having a gradation value (information indicating gradation) of "64." Furthermore, pass masks 501 to 508 in FIG. 5(c) are diagrams illustrating examples of pass masks corresponding to the first to eighth scans of droplets, respectively. In each scan, a maximum of one dot is printed per pixel, with a unit pixel resolution of 2400 dpi in the X direction and 1200 dpi in the Y direction. FIG. 5(d) is a diagram illustrating print data 511 to 518 corresponding to the first to eighth scans, respectively, generated by applying the pass masks 501 to 508 in FIG. 5(c) to the binary data shown in FIG. 5(b). 5(c) are mask patterns in which a total of one dot is printed on each pixel over eight scans. However, mask patterns in which two or more dots are printed on each pixel are also possible, and the mask pattern can be set according to the desired amount of droplets printed per unit area on the print medium.

[0027] As shown in Figure 5(a), a dither mask has a different threshold value set for each of a plurality of pixels. Here, if the gradation value of the multi-value data for each pixel is greater than the threshold value to be compared, the multi-value data is converted into binary data (1-bit data) indicating "droplet ejection" for that pixel. On the other hand, if the gradation value of the multi-value data for each pixel is equal to or less than the threshold value to be compared, the multi-value data is converted into binary data indicating "droplet non-ejection" for that pixel. Note that the following explanation describes a form in which the same value of multi-value data is input to all pixel regions within a certain unit area, but different values ​​of multi-value data may also be input to each pixel region.

[0028] For example, if the gradation value of the multi-value data for the previous pixel is "64," the threshold value for pixel 50 in the dither mask shown in FIG. 5(a) is "9" (<64), so the multi-value data corresponding to pixel 50 is converted into binary data indicating "droplet ejection." Furthermore, the threshold value for pixel 51 is "93" (≧64), so the multi-value data corresponding to pixel 51 is converted into binary data indicating "droplet non-ejection." In this way, by using the dither mask shown in FIG. 5(a), the binary data shown in FIG. 5(b) is generated from the multi-value data indicating the gradation value "64."

[0029] As shown in each of the pass masks 501 to 508 in Fig. 5(c), the pass mask is configured by arranging print permitting pixels that permit the ejection of droplets and non-print permitting pixels that do not permit the ejection of droplets. In each of the pass masks 501 to 508 in Fig. 5(c), the blacked-out areas represent print permitting pixels, and the whited-out areas represent non-print permitting pixels.

[0030] Here, the print data corresponding to each scan is generated by taking the logical product of the input binary data and the pass mask corresponding to each scan. That is, when binary data indicating droplet ejection is input to print permitting pixels, the binary data is converted into print data indicating droplet ejection. On the other hand, even when binary data indicating droplet ejection is input to non-print permitting pixels, the binary data is converted into print data indicating no droplet ejection.

[0031] Specifically, by applying the pass mask shown in pass mask 501 in Figure 5(c) corresponding to the first scan to the binary data shown in Figure 5(b), the binary data is distributed, and print data corresponding to the first scan shown as print data 511 in Figure 5(d) is generated. In the same way, the binary data shown in Figure 5(b) is distributed to each of the second to eighth scans, and print data corresponding to the second to eighth scans shown as print data 512 to 518 in Figure 5(d) are generated. In each of the first to eighth scans, an image is printed by ejecting droplets in accordance with the print data generated as described above.

[0032] The above-mentioned multi-pass printing method will be described in detail below. Here, the case where image data with a gradation value of 64 is input will be described. As described above, when image data with a gradation value of 64 is input, the printing data shown in each of the printing data 511 to 518 in Fig. 5(d) is generated, and here droplets are ejected in accordance with this printing data.

[0033] Figure 6 is a diagram illustrating a typical multi-pass printing method. It shows a situation in which printing is performed within a unit area on a print medium through eight print scans using a print head having 1,024 ejection ports in one ejection port array. For simplicity's sake, an example is shown using the 8-pixel x 8-pixel pass mask shown in Figure 5(c). Also shown is an example in which the print head 15 has one ejection port array.

[0034] The ejection ports 20 provided in the ejection port array 21 that ejects droplets are divided into eight recording groups 601, 602, 603, 604, 605, 606, 607, and 608 along the Y direction.

[0035] In the first printing scan, droplets are ejected from the printing group 601 onto an area 611 on the printing medium 12 in accordance with the printing data 511 in FIG. 5(d). As a result, droplets are ejected onto the printing medium at the positions indicated by black in A in FIG. 6. Next, the printing medium 12 is transported in the Y direction relative to the printing head 15 by a distance equivalent to 128 (=1024 / 8) ejection ports. After this, a second printing scan is performed.

[0036] During the second printing scan, droplets are ejected from printing group 602 onto area 611 on the printing medium in accordance with printing data 512 in FIG. 5(d). Also, droplets are ejected from printing group 601 onto area 612 in accordance with printing data 511 in FIG. 5(d). As a result of this second printing scan, an image such as that shown in area 611 of "row B" is formed on the printing medium 12.

[0037] Thereafter, the scanning of the recording head 15 and the relative transport of the recording medium 12 are alternately repeated. As a result, after the eighth recording scan, an image as shown in the "H row" area 611 is formed on the recording medium 12, and droplet ejection is completed for 25% of the pixel area that can be recorded.

[0038] A general example of 8-pass printing using a print head having 1024 ejection ports used in this embodiment has been described above.

[0039] Fig. 4 is a flowchart showing the image data processing process. The program for this flow is stored in, for example, ROM 302, and is executed by CPU 301. This flow starts when image processing unit 300 receives input of RGB data from external device 312 via image input unit 311. In Fig. 4, rectangular blocks indicate image processing steps, and parallelogram blocks indicate data input steps.

[0040] In step S401, the image processing unit 300 accepts input of image data (8-bit gradation for each of RGB). Similarly, it accepts input of white image data (8-bit gradation). The area that this white image occupies on the recording medium can be determined according to the color image to be overlaid, arbitrarily determined by the device user, or determined according to the recording conditions.

[0041] In step S402, the image processing unit 300 performs color adjustment processing and ink color separation processing to convert the input image data into multi-value color ink data corresponding to each of the multiple color inks (C, M, Y, K) used to print the image. Specifically, the input image data is converted into color ink data corresponding to the multiple ink colors available in the printing device for each predetermined area by referencing a color conversion lookup table (LUT). The same processing is performed on the white image data to convert it into white ink data.

[0042] The number of dimensions of the LUT means the number of components of the input image data. In this embodiment, since the input image data has three components, R, G, and B, a three-dimensional (3D)-LUT is used.

[0043] In step S403, the image processing unit 300 inputs the generated color ink data and white ink data to S404 and S406. The color ink data generated in S402 is, for example, 8-bit gradation for each color, and has a resolution of 600 dpi at this stage. The printing device expresses gradation for each printing area of ​​4 x 2 dots (4 dots in the X direction and 2 dots in the Y direction) to support a 2400 dpi x 1200 dpi printing mode. In other words, gradation is expressed for each unit area (1 pixel) at a resolution of 600 ppi x 600 ppi. Note that an index indicating the extent to which printing dots fill a unit area is called the printing duty (DUTY).

[0044] In step S404, the image processing unit 300 generates reaction liquid (RCT) data based on the color ink data and white ink data. Specifically, the amount of reaction liquid applied to each pixel is set based on a table (RCT data LUT) that stores the relationship between the ink application amount, white ink application amount, and reaction liquid application amount for each type of recording medium. Then, 8-bit image data (RCT data) corresponding to the application amount is generated. Details of setting the reaction liquid application amount will be described later, but here, at least for the color ink data, two RCT data for the two types of reaction liquid described below are generated. In step S405, the image processing unit 300 uses the generated RCT data (two for color inks and one for white ink) as input to S406.

[0045] In step S406, the image processing unit 300 binarizes the color ink data, white ink data, and RCT data using a dither mask. Binarization using a dither mask is the same as the process described with reference to FIG. 5. During these processes, the dither mask and pass mask stored in ROM 302 are expanded in RAM 303, and the data generated in each step is also stored in RAM 303. In step S407, the image processing unit 300 uses the generated binarized data as input to S408.

[0046] In step S408, the image processing unit 300 separates the color ink data, white ink data, and RCT data into passes. In the first embodiment, this is processed using the pass mask shown in Fig. 6. In step S409, the image processing unit 300 generates print data for driving the print elements arranged in the print head based on the data separated into scans (pass separation) in S408, and performs printing.

[0047] <Ink and reactant composition> The composition of the ink (water-soluble resin particle ink) used in this embodiment will be described. Hereinafter, "parts" and "%" are based on mass unless otherwise specified. The color inks (K, C, M, Y), white ink (W), and reaction liquid (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 face. Furthermore, ketone compounds such as acetone and cyclohexanone are preferred from the viewpoints of their function as a film-forming aid for resin particles and their swelling and solubility in a recording medium on which a resin layer is formed. Ethylene glycol derivatives such as tetraethylene glycol dimethyl ether, and heterocyclic compounds with a lactam structure, such as N-methylpyrrolidone and 2-pyrrolidone, are also 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.

[0048] 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; 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; alkylene glycols having an alkylene group containing 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; and 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. Examples of suitable water-soluble organic solvents include polyhydric alcohols such as trimethylolpropane and trimethylolethane. Examples include N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. The water-soluble organic solvents listed above can be used alone or in mixtures. It is preferable to use deionized water as the water. The content of the water-soluble organic solvent in the reaction solution (RCT) is not particularly limited. In addition to the above components, the color inks (K, C, M, Y) and white ink (W) can contain, as needed, antifoaming agents, preservatives, antifungal agents, and the like, in order to achieve the desired physical properties.

[0049] In addition, the color inks (K, C, M, Y), white ink (W), and reactive liquid (RCT) used in this embodiment all contain surfactants. Surfactants are used to improve the ink's ability to wet and spread on the recording medium. The more surfactant added, the stronger the property of lowering the ink's surface tension, improving the ink's ability to wet and spread on the recording medium. In this embodiment, a small amount of acetylene glycol EO adduct or the like is added as a surfactant, and the static surface tension of each ink is reduced to 30 x 10 -3 N / m or less, and the difference in static surface tension between the color inks is 2 x 10 -3 The static surface tension of each ink was adjusted to be within the range of about 22 to 24 × 10 -3 The static surface tension of the ink was measured using a fully automatic surface tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.). Note that the measuring device is not limited to the above-mentioned examples, as long as it can measure the static surface tension of the ink.

[0050] Furthermore, the pH of each ink in 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 colorant 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.

[0051] The color inks and white inks used in this embodiment contain a water-soluble resin emulsion. In this embodiment, "water-soluble resin emulsion" refers to polymer particles dispersed in water. Specifically, these include acrylic resin particles synthesized by emulsion polymerization of monomers such as (meth)acrylic acid alkyl esters or (meth)acrylic acid alkyl amides. Styrene-acrylic resin particles synthesized by emulsion polymerization of (meth)acrylic acid alkyl esters or (meth)acrylic acid alkyl amides with styrene monomers. Examples include polyethylene resin particles, polypropylene resin particles, polyurethane resin particles, and styrene-butadiene resin particles. Core-shell resin particles, in which the polymer composition of the core and shell of the resin particles differ, and resin particles obtained by emulsion polymerization around pre-synthesized acrylic particles used as seed particles to control particle size, are also acceptable. Furthermore, hybrid resin particles, in which different resin particles, such as acrylic resin particles and urethane resin particles, are chemically bonded, are also acceptable.

[0052] The color inks and white inks used in this embodiment contain a slip agent. In this embodiment, the term "slip agent" refers to wax particles or silicone oil. Specifically, examples of wax particles include synthetic wax particles such as Fischer-Tropsch wax (EMUSTAR-6315) manufactured by Nippon Seiro Co., Ltd. and polyolefin wax (Hitec E-9500) manufactured by Toho Chemical Industry Co., Ltd. Other examples include natural wax particles such as carnauba wax (Cellosol 524) manufactured by Chukyo Yushi Co., Ltd. and paraffin wax (AQUACER 497) manufactured by BYK Japan. Silicone oil may also be used as the slip agent, such as polyether-modified silicone (BYK333) manufactured by BYK Japan.

[0053] In this embodiment, in order to solve problems in images such as bleeding and beading, recording is performed using a reaction liquid for insolubilizing part or all of the solid components of the color inks and white ink.

[0054] The purpose of the reaction solution is to insolubilize dissolved dyes and dispersed pigments and resins. For this reason, examples of reactants in the reaction solution include polyvalent metal ions (e.g., magnesium sulfate, magnesium nitrate, magnesium chloride, emulsified calcium, aluminum sulfate, iron chloride, etc.). One type of flocculation using such cations is a system that uses a low-molecular-weight cationic polymer to neutralize the charge of a water-soluble resin emulsion and insolubilize anionic soluble substances.

[0055] Another reaction system is an insolubilization system using a reaction solution that utilizes a pH difference. As mentioned above, most color inks and white inks generally used in inkjet recording are stable on the alkaline side due to the properties of their colorants. For example, pH is generally between 7.0 and 10.0, and is often set around 8.5 to 9.5 from an industrial perspective and considering the influence of the external environment. To aggregate and solidify color inks and white inks in such systems, an acidic solution is added and the pH is changed, disrupting the stable state and causing the dispersed components to aggregate. For this purpose, an acidic solution can also be used as a reaction solution.

[0056] <Method of preparing ink and reaction liquid> ·Resin particle dispersion The resin particle dispersion used in the first embodiment was prepared by first adding the following three additive liquids dropwise in small amounts while stirring in a nitrogen atmosphere heated to 70°C, and polymerizing for 5 hours. Each additive liquid was a mixture containing a hydrophobic monomer consisting of 28.5 parts methyl methacrylate, a hydrophilic monomer consisting of 4.3 parts sodium p-styrenesulfonate and 30 parts water, and a polymerization initiator consisting of 0.05 parts potassium persulfate and 30 parts water. In this way, a 20% by mass resin particle dispersion was obtained.

[0057] Black ink (K1) Preparation of dispersion An anionic polymer P-1 [styrene / butyl acrylate / acrylic acid copolymer (weight ratio = 30 / 40 / 30), acid value 202, weight average molecular weight 6500] was prepared. This was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass polymer solution.

[0058] 600 g of the polymer solution, 100 g of carbon black, and 300 g of ion-exchanged water were mixed and mechanically stirred for a predetermined time, followed by centrifugal separation to remove undispersed material, including coarse particles, to obtain a black dispersion. The resulting black dispersion had a pigment concentration of 10% by mass.

[0059] (K2) Ink preparation The ink was prepared by adding the following components to the black dispersion liquid described above to achieve the desired concentration: After thoroughly mixing and stirring these components, the mixture was filtered under pressure using a microfilter with a pore size of 2.5 μm (manufactured by Fujifilm Corporation) to prepare a pigment ink with a pigment concentration of 2% by mass.

[0060] 20 parts of the above black dispersion 40 parts of the above resin particle dispersion Wax particles 3 parts Zonyl FSO-100 (DuPont fluorine-based surfactant) 0.05 parts 2-methyl-1,3-propanediol 15 parts 2-pyrrolidone 5 parts Acetylene glycol EO adduct (Kawaken Fine Chemicals Co., Ltd.) 0.5 parts Ion-exchanged water Remaining

[0061] Cyan ink (C1) Preparation of dispersion An AB-type block polymer with an acid value of 250 and a number-average molecular weight of 3,000 was prepared using benzyl acrylate and methacrylic acid as raw materials by a conventional method, neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water to prepare a homogeneous 50% by mass polymer solution.

[0062] 200 g of the polymer solution, 100 g of CI Pigment Blue 15:3, and 700 g of ion-exchanged water were mixed and mechanically stirred for a predetermined time, followed by centrifugal separation to remove non-dispersed material, including coarse particles, to obtain a cyan dispersion. The resulting cyan dispersion had a pigment concentration of 10% by mass.

[0063] (C2) Preparation of ink The ink was prepared by adding the following components to the cyan dispersion liquid to achieve the desired concentration: After thoroughly mixing and stirring these components, the mixture was filtered under pressure using a microfilter with a pore size of 2.5 μm (manufactured by Fujifilm Corporation) to prepare a pigment ink with a pigment concentration of 2% by mass.

[0064] 20 parts of the above cyan dispersion 40 parts of the above resin particle dispersion Wax particles 3 parts Zonyl FSO-100 (DuPont fluorine-based surfactant) 0.05 parts 2-methyl-1,3-propanediol 15 parts 2-pyrrolidone 5 parts Acetylene glycol EO adduct (Kawaken Fine Chemicals Co., Ltd.) 0.5 parts Ion-exchanged water Remaining

[0065] Magenta ink (M1) Preparation of dispersion Using benzyl acrylate and methacrylic acid as raw materials, an AB-type block polymer with an acid value of 300 and a number-average molecular weight of 2500 was prepared by a standard method, neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water to prepare a homogeneous 50% by mass polymer solution.

[0066] 100 g of the polymer solution, 100 g of CI Pigment Red 122, and 800 g of ion-exchanged water were mixed and mechanically stirred for a predetermined time, followed by centrifugal separation to remove non-dispersed material including coarse particles, to obtain a magenta dispersion. The resulting magenta dispersion had a pigment concentration of 10% by mass.

[0067] (M2) Ink preparation The ink was prepared by adding the following components to the magenta dispersion liquid described above to achieve the desired concentration: After thoroughly mixing and stirring these components, the mixture was filtered under pressure using a microfilter with a pore size of 2.5 μm (manufactured by Fujifilm Corporation) to prepare a pigment ink with a pigment concentration of 3% by mass.

[0068] 30 parts of the above magenta dispersion 40 parts of the above resin particle dispersion Wax particles 3 parts Zonyl FSO-100 (DuPont fluorine-based surfactant) 0.05 parts 2-methyl-1,3-propanediol 15 parts 2-pyrrolidone 5 parts Acetylene glycol EO adduct (Kawaken Fine Chemicals Co., Ltd.) 0.5 parts Ion-exchanged water Remaining

[0069] Yellow ink (Y1) Preparation of dispersion Anionic polymer P-1 was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass polymer solution.

[0070] 300 g of the polymer solution, 100 g of CI Pigment Yellow 74, and 600 g of ion-exchanged water were mixed and mechanically stirred for a predetermined time, followed by centrifugal separation to remove undispersed material, including coarse particles, to obtain a yellow dispersion. The resulting yellow dispersion had a pigment concentration of 10% by mass.

[0071] (Y2) Ink preparation The following components were mixed and thoroughly stirred to dissolve and disperse, and then pressure filtered through a microfilter (manufactured by Fujifilm Corporation) with a pore size of 1.0 μm to prepare a pigment ink with a pigment concentration of 3% by mass.

[0072] 30 parts of the above yellow dispersion 40 parts of the above resin particle dispersion Wax particles 3 parts Zonyl FSO-100 (DuPont fluorine-based surfactant) 0.025 parts 2-methyl-1,3-propanediol 15 parts 2-pyrrolidone 5 parts Acetylene glycol EO adduct (Kawaken Fine Chemicals Co., Ltd.) 1 part Ion-exchanged water Remaining

[0073] White ink (W1) Preparation of white dispersion An anionic polymer P-1 [styrene / butyl acrylate / acrylic acid copolymer (weight ratio = 30 / 40 / 30), acid value 202, weight average molecular weight 6500] was prepared. This was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass polymer solution.

[0074] 150 g of the above polymer solution, 500 g of titanium oxide, and 350 g of ion-exchanged water were mixed, and the titanium oxide was dispersed using a homogenizer. Subsequently, undispersed material, including coarse particles, was removed by centrifugation, and an appropriate amount of ion-exchanged water was added to obtain a white dispersion. The resulting white dispersion had a pigment concentration of 30% by mass.

[0075] (W2) Preparation of white ink To prepare the white ink, the above white dispersion was used, and the following components were mixed with it. After thorough stirring to dissolve and disperse the mixture, the mixture was filtered under pressure using a microfilter with a pore size of 2.5 μm (manufactured by Fujifilm Corporation) to prepare a pigment ink with a pigment concentration of 4% by mass.

[0076] 40 parts of the above white dispersion 40 parts of the above water-soluble resin emulsion dispersion Zonyl FSO-100 (DuPont fluorine-based surfactant) 0.025 parts 2-methyl-1,3-propanediol 15 parts 2-pyrrolidone 5 parts Acetylene glycol EO adduct (Kawaken Fine Chemicals Co., Ltd.) 1 part Ion-exchanged water (Kawaken Fine Chemicals Co., Ltd.) Remaining

[0077] Reaction solution The reaction liquid used in this embodiment contains multiple reactants that react with the pigment or resin particles contained in the ink to aggregate or gel the pigment or resin particles. In this embodiment, two different types of reaction liquids are used: a first reaction liquid (RCT1) and a second reaction liquid (RCT2).

[0078] The reaction liquid contains a reactant that reacts with the colorant component contained in the ink to aggregate or gel the colorant. Here, the reactant is a component that can reduce the dispersion stability of the ink when mixed on a recording medium or the like with an ink containing a pigment that is stably dispersed in an aqueous medium by the action of ionic groups. Specifically, a polyvalent metal salt, a water-soluble cationic polymer having cationic groups, a water-soluble organic acid, etc. can be used as the reactant for the reaction liquid.

[0079] RCT1 preferably contains at least a polyvalent metal salt as a reactant. RCT1 is a reaction liquid used primarily for color inks. The polyvalent metal salt can control the aggregation state when mixed with color ink, and is expected to improve image quality characteristics such as gloss and color development.

[0080] RCT2 contains at least a cationic polymer as a reactant. RCT2 is a reaction liquid mainly used for white ink. Cationic polymers contain many ionic polar groups per polymer molecule, resulting in a high charge density, and therefore have an excellent ability to reduce the dispersibility of color pigments.

[0081] Reaction liquids containing large amounts of reactants, such as cationic polymers, exhibit strong aggregating properties when mixed with color inks. This results in strong aggregation of ink dots on the recording medium, inhibiting ink dot leveling (smoothing), and thus degrading the image quality characteristics of the recorded product. On the other hand, white inks are used to control the light-blocking properties of images when transparent films or other recording media are used. In this case, it is necessary to form a white ink layer with high light-blocking (concealing) properties from the opposite side of the recording surface, and the white ink contains a higher amount of colorant than color inks. Therefore, in order to properly aggregate the white ink, which contains a large amount of colorant, on the recording medium to form a layered image, it is preferable that RCT2 contain at least a cationic polymer.

[0082] The polyvalent metal salt is an example of a "first reactant," and the cationic polymer is an example of a "second reactant." In this embodiment, the content of the reactive component is preferably 0.1% by mass or more and 90.0% by mass or less, and more preferably 1.0% by mass or more and 70.0% by mass or less, based on the total mass of the composition contained in the reaction liquid.

[0083] RCT1 Magnesium sulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as a reactant component, and the following components were mixed to prepare RCT1.

[0084] Magnesium sulfate 2 parts 2-pyrrolidone 5 parts 2-methyl-1,3-propanediol 15 parts Acetylene glycol EO adduct (Kawaken Fine Chemicals Co., Ltd.) 0.5 parts Ion-exchanged water Remaining

[0085] RCT2 The following cationic polymer was used as a reactant component, and the following components were mixed to prepare RCT2. The cationic polymer was blended to the following weight in solids content, taking into account the solid content of the solution used.

[0086] 2 parts cationic polymer (Unisense FPA100LU manufactured by Senka Corporation) 2-pyrrolidone 5 parts 2-methyl-1,3-propanediol 15 parts Acetylene glycol EO adduct (Kawaken Fine Chemicals Co., Ltd.) 0.5 parts Ion-exchanged water Remaining

[0087] The above-mentioned RCT1 and RCT2 are examples of a "first reaction solution" and a "second reaction solution," respectively. In this embodiment, RCT1 is exemplified as containing only a polyvalent metal salt as a reactant, but it is sufficient that at least a polyvalent metal salt is contained, and multiple types of reactants may be contained. Furthermore, while RCT2 is exemplified as containing only a cationic polymer as a reactant, it is sufficient that at least a cationic polymer is contained, and it may be exemplified as containing multiple types of reactants.

[0088] For example, RCT1 may contain only a polyvalent metal salt as a reactant, while RCT2 may contain both a polyvalent metal salt and a cationic polymer. Alternatively, RCT1 may contain both a polyvalent metal salt and a cationic polymer, while RCT2 may contain only a cationic polymer as a reactant. Alternatively, RCT1 and RCT2 may both contain both a polyvalent metal salt and a cationic polymer as reactants, but in different proportions.

[0089] <Details of Setting the Amount of Reaction Solution to be Applied (S404)> A method for determining the amount of reaction liquid to be applied that is suitable for implementing the image recording method of this embodiment will now be described in detail. In this embodiment, color inks and white ink are applied directly onto the recording medium 12 for recording. Then, information regarding the reaction liquid to be applied to each predetermined area of ​​the recording medium 12 is determined based on information regarding the amount of ink applied.

[0090] First, we will explain the case where RCT data is generated according to the total application amount of each color ink of black, cyan, magenta, and yellow applied to each predetermined area of ​​the recording medium 12. Note that the information on the application amount of ink used in the RCT data generation process does not necessarily have to be the total application amount of the color inks, and RCT data may also be generated according to the application amount of white ink or each color ink.

[0091] FIG. 7 is a diagram showing a table storing the relationship between the amount of ink applied and the amount of reaction liquid applied. That is, it is a diagram explaining the contents of the LUT for RCT data described in S404. FIGS. 7(a) and 7(b) each show an example of a different table. FIG. 7 shows an example of an LUT for a printed matter printed on a vinyl chloride sheet IJ1220-10 (glossy) (3M Japan Ltd.) using the inkjet printing apparatus of this embodiment. The image processing unit 300 controls the application amounts of RCT1 and RCT2 according to the application amounts of color inks based on the LUT corresponding to FIG. 7.

[0092] The optimal relationship between the amount of color ink and reaction liquid applied may vary depending on the recording medium, recording mode, etc. Therefore, the image processing unit 300 stores multiple tables corresponding to each recording mode in advance in the ROM 302, and the control unit performs processing by referencing the appropriate LUT depending on the selected recording mode. Furthermore, when generating RCT data for each color ink, different tables may be used for each color ink. These tables may be determined for each recording condition, taking into consideration the suppression of graininess, bleeding, and precipitation in the recorded image.

[0093] In Figure 7(a), the horizontal axis represents the amount of color ink applied, and the vertical axis represents the amount of RCT applied. The horizontal axis is divided into a low gradation region (LA) where the amount of color ink applied is small (low duty) and a high gradation region (HA) where the amount of color ink applied is large (high duty). The threshold amount of application, which is the boundary between the high gradation region and the low gradation region, can be set arbitrarily. At the boundary between each region, the amount of reaction liquid applied is set so that the RCT1 and RCT2 graphs are continuous, taking into account the continuity of the image.

[0094] The amount of color ink applied, which serves as a reference value for the above-mentioned region boundary and serves as an index for determining the appropriate use of such reaction liquid ejection control, varies depending on the ink and reaction liquid used, the type of recording medium, etc. Preferably, it is selected appropriately within the range of 16 to 48 ng / 600 dpi, which corresponds to a print duty range of 100% to 300%. Note that a print duty of 100% is the target for covering a predetermined region of the recording medium 12, and a print duty of 300% is the target for saturating the color density of the image.

[0095] As shown in Figure 7(a), in the low gradation region, only RCT1 is selected, the application amount is determined based on the table, and the ink is recorded in a predetermined area on the recording medium 12. In the high gradation region, both RCT1 and RCT2 are selected, the application amount is determined based on the table for each ink, and the ink is recorded in a predetermined area on the recording medium 12. Furthermore, in the high gradation region, the ratio of the application amount of RCT2 to the total application amount of RCT1 and RCT2 varies depending on the application amount of the color ink. Specifically, the ratio of RCT2 varies so that the greater the application amount of the color ink, the greater the change.

[0096] If a table were to be created in which only RCT2 was selected in the high gradation region and only RCT1 was selected in the low gradation region, there would be a risk that the gradation of the printed image would not be continuous at the boundary between the two gradation regions. For this reason, in Figure 7(a), as the amount of color ink applied increases, the proportion of RCT1 applied decreases and the proportion of RCT2 applied increases.

[0097] As mentioned above, only RCT1 is selected and printed in low gradation areas. Because the color density is low in low gradation areas, the cloudiness of the image caused by precipitation is less noticeable. On the other hand, because the low gradation areas are not completely covered with ink (the printing duty is less than 100%), unevenness due to aggregation is likely to occur on the printed surface, and glossiness is likely to decrease. Therefore, by selecting and printing only RCT1 in low gradation areas, it is possible to improve the glossiness of the image (compared to when only RCT2 is used or when RCT1 and RCT2 are used together).

[0098] On the other hand, in high-gradation areas, the amount of ink applied is large, so the surface of the recorded image is easily smoothed. Therefore, the gloss of the recorded image is less likely to decrease due to the strong coagulation of the cationic polymer. On the other hand, the color density of the image is high, so cloudiness of the image due to precipitation is more noticeable. Therefore, by recording in this area using both RCT1 and RCT2, it is possible to suppress cloudiness due to precipitation.

[0099] As described above, according to the first embodiment, in an inkjet recording apparatus that uses ink and a reaction liquid, the components of the reaction liquid are changed according to the recording gradation of the ink (amount of ink applied), thereby enabling high-quality image recording that achieves both glossiness in recording areas with low recording gradation and color development in recording areas with high recording gradation.

[0100] In the above-described embodiment, an example has been described using a table (FIG. 7(a)) in which RCT1 and RCT2 are used together only in high gradation regions. However, depending on the concentration of the reactant contained, its reactivity with the color ink, and the type of recording medium, it may be necessary to suppress the occurrence of precipitation even in low gradation regions. In such cases, by using an LUT such as that shown in FIG. 7(b), it is possible to suppress precipitation even in lower gradation regions. In the LUT of FIG. 7(b), RCT1 and RCT2 are used together in both low gradation regions and high gradation regions, and the ratio of RCT2 is set to increase as the amount of color ink applied increases.

[0101] Furthermore, in this embodiment, control using the total amount of applied color inks as the ink application amount information used in the reaction liquid data generation process has been described. However, as previously mentioned, reaction liquid data may also be generated based on application amount information for each color ink. Specifically, because the impact of color degradation due to cloudiness varies depending on the image brightness, a method can be used in which different LUTs are used for inks with different image brightnesses even when the same ink application amount is used. For example, the ratio of the RCT2 application amount is set higher for black (K), which has a relatively lower brightness than yellow (Y), which has the same ink application amount. This makes it possible to obtain a glossier image when using inks that are less affected by color degradation due to cloudiness. Similarly, when dark inks and light inks containing different amounts of colorant are used, different LUTs may be used for those inks.

[0102] Furthermore, while this embodiment has described the reaction liquid data generation process for color inks, similar control may also be performed for white ink. In white ink, the strong coagulation properties of the aforementioned cationic polymer may reduce the ink's adhesion to the recording medium, which may lead to a reduction in gloss and the ink film being more likely to be scraped off the recording medium, particularly in low gradation areas. Even in such cases, the control of this embodiment can be used to suppress the reduction in adhesion to the recording medium.

[0103] Furthermore, when recording on a transparent recording medium (such as a transparent film), a white ink layer recorded with white ink and a color ink layer recorded with color inks can be laminated to obtain an image with good color development. Even in such a case, gloss and precipitation can be controlled by using the control of this embodiment. For example, a method of first applying white ink to the recording medium and then applying color inks on top of the white ink layer, or a method of applying each ink in the reverse order, can be used. Note that two layers are not necessarily required; recording may also be performed by laminating multiple color ink layers and white ink layers.

[0104] It should be noted that applicable inks are not limited to those with the above-mentioned compositions. Furthermore, dye inks, pigment inks, or both can be used as color inks. Furthermore, the present invention can be applied to various inkjet recording methods, including, for example, so-called full-line type recording methods that use a long recording head extending in the width direction of the recording medium.

[0105] (Second embodiment) In the second embodiment, the amount of reaction liquid applied is further controlled depending on the temperature of the recording medium (given fixing temperature) in the heat fixing process after recording of the ink and reaction liquid. Specifically, a mode in which a different LUT is selected depending on the fixing temperature will be described. Note that the device configuration (FIGS. 1 to 3), the composition of the ink and reaction agent, and the method of producing the ink and reaction liquid are the same as those in the first embodiment, and therefore will not be described here.

[0106] <Device Operation> 8 is a flowchart showing the image data processing steps in the second embodiment. Note that steps S801 to S803 and S805 to S809 are the same as steps S401 to S403 and S405 to S409 in the first embodiment, and therefore a description thereof will be omitted.

[0107] In step S804, the image processing unit 300 generates reactive liquid (RCT) data based on the fixing temperature (temperature of the recording medium during fixing), the color ink data, and the white ink data. Specifically, a different RCT data LUT is selected depending on the fixing temperature set by the user.

[0108] FIG. 9 is a diagram showing a table storing the relationship between the ink application amount and the reaction liquid application amount. That is, it is a diagram explaining the contents of the RCT data LUT referenced in S804. In FIG. 9, L1 indicates the LUT for RCT2 selected when the fixing temperature is 80° C. (T1), and L2 indicates the LUT for RCT2 selected when the fixing temperature is 90° C. (T2). T1 and T2 are examples of the "first temperature" and "second temperature," respectively. In the second embodiment, LUTs such as those shown in FIG. 9 are stored in ROM 302 for a plurality of fixing temperatures for combinations of RCT1 and RCT2 application amounts for each color ink and white ink application amount.

[0109] Here, L1 exemplarily shows the same as in FIG. 7(a). L2 uses the same RCT printed in each gradation region. That is, only RCT1 is selected in the low gradation region, and both RCT1 and RCT2 are used in the high gradation region. Also, in the high gradation region, the ratio of the amount of RCT2 applied to the total amount of RCT1 and RCT2 applied varies depending on the amount of color ink applied, which is the same for L1 and L2. However, the change in the ratio of the amount of RCT2 applied to the total amount of RCT1 and RCT2 applied in response to the change in the amount of color ink applied differs between L1 and L2 (i.e., depends on the fixing temperature).

[0110] When the same LUT is used to determine the amount of reaction liquid applied, the higher the fixing temperature, the less likely cloudiness occurs. This is thought to be because the faster the ink and reaction liquid dry, the less likely they are to grow into large crystals, making it less likely that color deterioration due to precipitation will occur. Therefore, for higher temperatures (T2 > T1), L2 is used as the LUT for RCT2, and the amount of RCT2 applied is controlled to be smaller.

[0111] As explained above, according to the second embodiment, in an inkjet recording apparatus that uses ink and reaction liquid, in addition to the control of the first embodiment, the application amounts of two types of reaction liquid are changed based on the fixing temperature. By performing such control, it is possible to obtain a glossier image in the high gradation area and reduce the ink consumption of RCT2.

[0112] Although the present embodiment shows an example of control in which a different LUT is selected depending on the fixing temperature, control may also be performed in which a different LUT is selected depending on the type of recording medium. For example, a different table may be selected depending on the ink absorbency of the recording medium, or a different table may be selected depending on the temperature and humidity of the environment in which the recording device is used.

[0113] Furthermore, one method for evaluating the ink absorbency of recording media is the Bristow method, described in No. 51 "Test Method for Liquid Absorbency of Paper and Paperboard" of the "JAPAN TAPPI Paper and Pulp Test Methods." A detailed explanation is omitted here as it is explained in many commercially available books, but the outline is as follows.

[0114] A certain amount of ink is poured into a holding container with an opening slit of a specified size, and the ink is brought into contact with a recording medium that has been processed into a strip and wrapped around a disk through the slit. With the position of the holding container fixed, the disk is rotated and the area (length) of the ink band that is transferred to the recording medium is measured. The amount of ink transferred per unit area (ml / m) is calculated from the area of ​​the measured ink band. 2 ) can be calculated, and the metastatic volume (ml / m 2 ) indicates the volume of ink absorbed by the recording medium in a given time. The given time is defined as the transfer time. Transfer time (milliseconds) 1 / 2 ) corresponds to the contact time between the slit and the recording medium, and is calculated from the speed of the disk and the width of the opening slit.

[0115] By selecting an LUT that reduces the amount of RCT2 applied to a recording medium that has a large amount of transfer (=high absorbency) in a transfer time of 1 second, as measured in this way, the same effect as in the present embodiment described above can be obtained.

[0116] (Third embodiment) In the third embodiment, the amount of reaction liquid applied is further controlled depending on the glossiness of the recording medium used for recording. Specifically, a mode in which a different LUT is selected depending on the fixing temperature will be described. Note that the device configuration (FIGS. 1 to 3), the composition of the ink and reaction agent, and the method of preparing the ink and reaction liquid are the same as those in the first embodiment, and therefore will not be described here.

[0117] <Device Operation> 10 is a flowchart showing the image data processing steps in the third embodiment. Note that steps S1001 to S1003 and S1005 to S1009 are the same as steps S401 to S403 and S405 to S409 in the first embodiment, and therefore a description thereof will be omitted.

[0118] In step S1004, the image processing unit 300 generates reactive liquid (RCT) data based on the glossiness of the recording medium, the color ink data, and the white ink data. Specifically, a different RCT data LUT is selected depending on the glossiness of the recording medium used for recording.

[0119] FIG. 11 is a diagram showing a table storing the relationship between the amount of ink applied and the amount of reaction liquid applied. That is, it is a diagram explaining the contents of the RCT data LUT referenced in S1004. In FIG. 11, L3 indicates the LUT selected when the recording medium is a vinyl chloride sheet "IJ1220-10 (glossy)." Furthermore, L4 indicates the LUT selected when the recording medium is a vinyl chloride sheet "IJ1220-20 (matt)" (3M Japan Ltd.). In the following explanation, these will be referred to as "glossy PVC sheet" and "matte PVC sheet." The glossiness of the matte PVC sheet according to JIS Z8741 (measured here at an angle of 60 degrees) is lower than that of the glossy PVC sheet. The glossy PVC sheet and matte PVC sheet are examples of a "first recording medium" and a "second recording medium," respectively.

[0120] Here, L3 exemplarily shows the same as in FIG. 7(a). L4 uses the same RCTs in each gradation region. That is, only RCT1 is selected in the low gradation region, and both RCT1 and RCT2 are used in the high gradation region. Also, in the high gradation region, the ratio of the amount of RCT2 applied to the total amount of RCT1 and RCT2 applied varies depending on the amount of color ink applied, which is the same for L3 and L4. However, the change in the ratio of the amount of RCT2 applied to the total amount of RCT1 and RCT2 applied in response to the change in the amount of color ink applied differs between L3 and L4 (i.e., depending on the glossiness of the recording medium).

[0121] When determining the amount of reaction liquid to be applied using the same LUT, the lower the gloss of the recording medium, the smaller the impact of gloss reduction. This is thought to be because, when the gloss of the recording medium itself is low, there is less difference between recording using a reaction liquid with strong cohesive power and recording using a reaction liquid with weak cohesive power. Therefore, when using a recording medium with lower gloss (matte PVC sheet), L4 is used, and the amount of RCT2 applied is controlled to be greater in the high gradation region.

[0122] In this embodiment, it is assumed that information regarding the glossiness of the recording medium is stored in advance as a table in ROM 302, and that this information is acquired in S1004. Alternatively, a sensor for measuring glossiness may be provided in the recording device body, the glossiness of the recording medium may be measured, and a table may be selected based on the measured glossiness. In this way, it is possible to perform the above-described reaction liquid deposition amount control for storage media other than those types stored in ROM 302 in advance.

[0123] As described above, according to the third embodiment, in an inkjet recording apparatus that uses ink and reaction liquid, in addition to the control of the first embodiment, the amounts of two types of reaction liquid applied are changed based on the glossiness of the recording medium. By performing such control, for example, in high gradation areas on a recording medium with low glossiness, the effect of reducing the impact of cloudiness on the image can be obtained more effectively than in the first embodiment.

[0124] The disclosure of this specification includes the following inkjet printing apparatus, printing method, and program. (Item 1) An inkjet recording apparatus for recording an image on a recording medium, a recording means including a first ejection unit that ejects ink containing resin particles and coloring material, and a second ejection unit that ejects a reaction liquid that reacts with the resin particles and coloring material in the ink to cause aggregation or gelation; a determination unit that determines the amount of the reaction liquid to be applied for each partial area of ​​the recording medium based on the amount of the ink to be applied; Equipped with the second discharge unit is configured to discharge, as the reaction liquid, at least one of a first reaction liquid having a first composition and a second reaction liquid having a second composition different from the first composition; The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that a first ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a first amount, is different from a second ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a second amount that is larger than the first amount. An inkjet recording apparatus characterized by: (Item 2) the first reaction solution contains a polyvalent metal salt or an organic acid as the first composition; The second reaction liquid contains a cationic polymer as the second composition. 2. The inkjet recording apparatus according to item 1, (Item 3) The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that the second ratio is greater than the first ratio. 3. The inkjet recording apparatus according to item 1 or 2. (Item 4) the first ejection unit is configured to be able to eject a plurality of color inks that are different from one another; The determining unit determines the application amounts of the first reaction liquid and the second reaction liquid based on the total application amounts of the plurality of color inks. 4. The inkjet recording apparatus according to any one of items 1 to 3, (Item 5) the first ejection unit is configured to be able to eject a plurality of color inks that are different from one another; the determining means determines the application amounts of the first reaction liquid and the second reaction liquid for each of the application amounts of the plurality of color inks; With respect to the first color ink and the second color ink included in the plurality of color inks, at least one of the first ratio and the second ratio is different. 4. The inkjet recording apparatus according to any one of items 1 to 3, (Item 6) a fixing unit that heats and fixes the image recorded by the recording unit onto the recording medium at a given fixing temperature; The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that, at least in a high gradation region where the amount of ink applied is greater than a threshold amount, a third ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the fixing temperature is a first temperature, is greater than a fourth ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the fixing temperature is a second temperature higher than the first temperature. 6. The inkjet recording apparatus according to any one of items 1 to 5, (Item 7) further comprising an acquisition unit for acquiring information regarding the ink absorbency of the recording medium; The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that, at least in a high gradation region where the amount of ink applied is greater than a threshold amount, a third ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the absorbency is a first absorbency, is greater than a fourth ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the absorbency is a second absorbency higher than the first absorbency. 6. The inkjet recording apparatus according to any one of items 1 to 5, (Item 8) further comprising an acquisition unit for acquiring information regarding the glossiness of the recording medium, The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that a third ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the glossiness is a first glossiness, is smaller than a fourth ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the glossiness is a second glossiness lower than the first glossiness, at least in a high gradation region where the amount of the ink to be applied is greater than a threshold amount of application. 6. The inkjet recording apparatus according to any one of items 1 to 5, (Item 9) A recording method executed by an inkjet recording apparatus that records an image on a recording medium, comprising: the inkjet recording apparatus comprises a recording unit including a first ejection unit that ejects ink containing resin particles and coloring material, and a second ejection unit that ejects a reaction liquid that reacts with the resin particles and coloring material in the ink to aggregate or gel; the second discharge unit is configured to discharge, as the reaction liquid, at least one of a first reaction liquid having a first composition and a second reaction liquid having a second composition different from the first composition; The recording method includes: a determining step of determining the amounts of the first reaction liquid and the second reaction liquid to be applied for each partial region of the recording medium so that a first ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a first amount, and a second ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a second amount that is larger than the first amount, are different. A recording method characterized by: (Item 10) Item 10. A program for causing a computer to execute the recording method according to Item 9.

[0125] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0126] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0127] 10 platen; 11 carriage; 12 recording medium; 15 recording head; 300 image processing unit; 301 CPU; 302 ROM; 303 RAM; 311 image input unit

Claims

1. An inkjet recording apparatus for recording an image on a recording medium, a recording means including a first ejection unit that ejects ink containing resin particles and coloring material, and a second ejection unit that ejects a reaction liquid that reacts with the resin particles and coloring material in the ink to cause aggregation or gelation; a determination unit that determines the amount of the reaction liquid to be applied for each partial area of ​​the recording medium based on the amount of the ink to be applied; Equipped with the second discharge unit is configured to discharge, as the reaction liquid, at least one of a first reaction liquid having a first composition and a second reaction liquid having a second composition different from the first composition; The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that a first ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a first amount, is different from a second ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a second amount that is larger than the first amount. An inkjet recording apparatus characterized by:

2. the first reaction solution contains a polyvalent metal salt or an organic acid as the first composition; The second reaction liquid contains a cationic polymer as the second composition.

2. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is a recording medium.

3. The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that the second ratio is greater than the first ratio.

3. The inkjet recording apparatus according to claim 2, wherein the inkjet recording apparatus is a recording medium.

4. the first ejection unit is configured to be able to eject a plurality of color inks that are different from one another; The determining unit determines the application amounts of the first reaction liquid and the second reaction liquid based on the total application amounts of the plurality of color inks.

2. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is a recording medium.

5. the first ejection unit is configured to be able to eject a plurality of color inks that are different from one another; the determining means determines the application amounts of the first reaction liquid and the second reaction liquid for each of the application amounts of the plurality of color inks; At least one of the first ratio and the second ratio of the first color ink and the second color ink included in the plurality of color inks is different.

2. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is a recording medium.

6. a fixing unit that heats and fixes the image recorded by the recording unit onto the recording medium at a given fixing temperature; The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that, at least in a high gradation region where the amount of ink applied is greater than a threshold amount, a third ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the fixing temperature is a first temperature, is greater than a fourth ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the fixing temperature is a second temperature higher than the first temperature.

3. The inkjet recording apparatus according to claim 2, wherein the inkjet recording apparatus is a recording medium.

7. further comprising an acquisition unit for acquiring information regarding the ink absorbency of the recording medium; The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that, at least in a high gradation region where the amount of ink applied is greater than a threshold amount, a third ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the absorbency is a first absorbency, is greater than a fourth ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the absorbency is a second absorbency higher than the first absorbency.

3. The inkjet recording apparatus according to claim 2, wherein the inkjet recording apparatus is a recording medium.

8. further comprising an acquisition unit for acquiring information regarding the glossiness of the recording medium, The determining means determines the amounts of the first reaction liquid and the second reaction liquid to be applied so that a third ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the glossiness is a first glossiness, is smaller than a fourth ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the glossiness is a second glossiness lower than the first glossiness, at least in a high gradation region where the amount of the ink to be applied is greater than a threshold amount to be applied.

3. The inkjet recording apparatus according to claim 2, wherein the inkjet recording apparatus is a recording medium.

9. A recording method executed by an inkjet recording apparatus that records an image on a recording medium, comprising: the inkjet recording apparatus comprises a recording unit including a first ejection unit that ejects ink containing resin particles and coloring material, and a second ejection unit that ejects a reaction liquid that reacts with the resin particles and coloring material in the ink to aggregate or gel; the second discharge unit is configured to discharge, as the reaction liquid, at least one of a first reaction liquid having a first composition and a second reaction liquid having a second composition different from the first composition; The recording method includes: a determining step of determining, for each partial region of the recording medium, the amounts of the first reaction liquid and the second reaction liquid to be applied so that a first ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a first amount, and a second ratio, which is a ratio of the amount of the second reaction liquid to the total amount of the first reaction liquid and the second reaction liquid when the amount of the ink to be applied is a second amount that is larger than the first amount, are different. A recording method characterized by:

10. A program for causing a computer to execute the recording method according to claim 9.

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