Image processing apparatus, recording apparatus, image processing method, recording method, and program

Abstract

To enable an image recorded with color inks and fluorescent inks to be observed as an image in which defects may occur depending on the observation angle.SOLUTION: An image processing apparatus generates data to be output to a recording apparatus which records an image on a recording medium by using fluorescent inks containing fluorescent components, color inks containing no fluorescent component, and a clear ink containing no color material and includes: generation means configured to generate recording data to cause the recording apparatus to apply the inks based on data of an image; and output means configured to output the recording data. The generation means generates the recording data to cause the recording apparatus to apply the clear ink to the recording medium so as to reduce a difference in a degree of change in brightness depending on an observation angle between a region to which the fluorescent ink is applied and a region to which the color ink is applied.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present disclosure relates to a technique for printing an image by ejecting ink onto a printing medium while scanning a print head. [Background technology]

[0002] Inks that use fluorescent components (hereafter referred to as "fluorescent inks") produce vivid colors and are therefore used for printing posters, POP displays, and other notices, as well as packaging for food and beverage products.

[0003] Patent Document 1 describes an inkjet recording method capable of recording an image with excellent fluorescence intensity using a fluorescent ink. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-8112 Summary of the Invention [Problem to be solved by the invention]

[0005] The subtractive inks commonly used in recording devices, such as cyan (C), magenta (M), yellow (Y), and black (K), contain colorants that absorb light of specific wavelengths and produce color by reflecting or transmitting the unabsorbed light. On the other hand, the fluorescent components contained in fluorescent inks absorb excitation light, go from the ground state to an excited state, and emit light in the process of returning to the ground state, so they emit light uniformly in almost all directions without depending much on the direction of the incident light.

[0006] Such colored inks and fluorescent inks may have different characteristics in terms of how their brightness changes depending on the observation angle (hereinafter referred to as "angle of deviation characteristics"). If the angle of deviation characteristics differ, a difference in brightness will occur between the areas recorded with colored inks and the areas recorded with fluorescent inks, depending on the observation angle. In this case, a printout created by recording an image with colored inks and fluorescent inks may be observed as an image with defects, such as a loss of color balance, depending on the observation angle.

[0007] An object of the present disclosure is to prevent images recorded with color inks and fluorescent inks from appearing to have defects depending on the observation angle. [Means for solving the problem]

[0008] The image processing device disclosed herein is an image processing device that generates data to be output to a recording device that records an image on a recording medium using fluorescent ink containing a fluorescent component, colored inks that do not contain a fluorescent component, and clear ink that does not contain a coloring material, and has a generation means that generates recording data for causing the recording device to apply ink based on image data, and an output means that outputs the recording data, wherein the generation means generates the recording data for causing the recording device to apply the clear ink to the recording medium so as to reduce the difference in the degree of brightness change depending on the observation angle between an area to which the fluorescent ink is applied and an area to which the colored ink is applied. Effect of the Invention

[0009] According to the technology of the present disclosure, it is possible to prevent images recorded with color inks and fluorescent inks from appearing to have defects depending on the observation angle. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 illustrates a configuration of a printing system. [Diagram 2] FIG. 1 is a diagram showing the configuration of a recording apparatus. [Diagram 3]5A and 5B are diagrams for explaining the operation of recording an image by scanning the recording head. [Figure 4] FIG. 1 is a schematic diagram showing an image expression controlled by an area modulation method. [Diagram 5] This is intended to explain the characteristics of the ink. [Figure 6] FIG. 4 is a graph showing the deflection angle characteristics of fluorescent ink and colored ink. [Figure 7] 1 is a schematic representation of the deflection angle characteristics. [Figure 8] 11A and 11B are diagrams for explaining examples of image defects caused by differences in deflection angle characteristics. [Figure 9] FIG. 4 is a diagram showing measurement results of a sample obtained by a recording device. [Figure 10] 5A and 5B are schematic diagrams showing the deflection angle characteristics of each ink or the deflection angle characteristics of a combination of inks. [Figure 11] FIG. 2 is a diagram showing the functional configuration of the image processing apparatus. [Figure 12] 6 is a flowchart showing a process for generating print data. [Figure 13] FIG. 2 is a diagram showing the functional configuration of the image processing apparatus. [Figure 14] 6 is a flowchart showing a process for generating print data. [Figure 15] FIG. 13 is a graph showing the ratio R and deflection angle characteristics of a sample. [Figure 16] FIG. 2 is a diagram showing the functional configuration of the image processing apparatus. [Figure 17] 6 is a flowchart showing a process for generating print data. [Figure 18] FIG. 4 is a diagram showing an example of an LUT used to determine a target deflection angle characteristic. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the technology of the present disclosure will be described with reference to the drawings.

[0012] <Embodiment 1> [Printing system configuration] 1 is a diagram showing the configuration of a printing system applicable to this embodiment. The printing system includes an image processing device 1, a recording device 111, an input device 110, a HDD 113, a general-purpose drive 114, and a display 115.

[0013] [Hardware configuration of image processing device] The image processing device 1 is, for example, a computer and includes a CPU 101, a ROM 102, a RAM 103, a VC (video card) 104, a general-purpose I / F (interface) 105, a SATA (serial ATA) I / F 106, and a NIC (network interface card) 107.

[0014] The CPU 101 executes an OS (operating system) or various programs stored in the ROM 102 or HDD (hard disk drive) 113, etc., using the RAM 103 as a work memory. The CPU 101 also controls each component via a system bus 108. Note that, in the processing according to the flowcharts described below, program codes stored in the ROM 102 or HDD 113, etc., are expanded in the RAM 103 and executed by the CPU 101. A display 115 is connected to the VC 104.

[0015] An input device 110 such as a mouse or a keyboard, or a recording device 111 is connected to the general-purpose I / F 105 via a serial bus 109. An HDD 113 or a general-purpose drive 114 that reads and writes data from and to various recording media is connected to the SATA I / F 106 via a serial bus 112. The NIC 107 inputs and outputs information to and from external devices. The CPU 101 uses the various recording media mounted on the HDD 113 or the general-purpose drive 114 as storage locations for various data.

[0016] The CPU 101 displays a UI (user interface) screen provided by a program on a display 115, and receives inputs such as user instructions received via an input device 110.

[0017] [Recording device configuration] 2 is a diagram showing the configuration of the recording device 111. The recording device 111 in this embodiment is, for example, an inkjet printer that records an image by ejecting ink onto a recording medium.

[0018] The recording device 111 has a head cartridge 201, a carriage 202, a guide shaft 203, a main scanning motor 204, a motor pulley 205, a driven pulley 206, a timing belt 207, a recording medium 208, and a conveying roller 209. The recording device 111 also has an auto sheet feeder (hereinafter referred to as ASF) 210, a paper feed motor 211, a pickup roller 212, a line feed motor (hereinafter referred to as LF motor) 213, a paper end sensor 214, and a control unit 220.

[0019] The head cartridge 201 has a print head consisting of a plurality of ejection ports, and an ink tank that supplies ink to the print head. Also, a connector is provided for receiving signals for driving each ejection port of the print head. The ink tanks included in the head cartridge 201 are configured as ink tanks corresponding to subtractive color inks (cyan, magenta, yellow, and black), fluorescent pink ink, first clear ink, and second clear ink, respectively. Each ink tank is independently filled with the corresponding ink. As will be described later, since there are multiple types of fluorescent color inks such as fluorescent pink ink, the ink tank may be configured to be capable of ejecting multiple types of fluorescent ink.

[0020] The head cartridge 201 is replaceably mounted on a carriage 202, and the carriage 202 is provided with a connector holder for transmitting a drive signal and the like to the head cartridge 201 via a connector. The carriage 202 is capable of reciprocating along a guide shaft 203. Specifically, the carriage 202 is driven by a main scanning motor 204 as a drive source via a drive mechanism including a motor pulley 205, a driven pulley 206, and a timing belt 207, and the position and movement of the carriage 202 are controlled. In this embodiment, the movement of the carriage 202 along the guide shaft 203 is referred to as "main scanning", and the movement direction is referred to as "main scanning direction".

[0021] A recording medium 208 such as printing paper is placed on the ASF 210. During image recording, a pickup roller 212 rotates via a gear by the drive of a paper feed motor 211, and the recording medium 208 is separated and fed one by one from the ASF 210. Furthermore, the recording medium 208 is conveyed to a recording start position facing the discharge port face of the head cartridge 201 on the carriage 202 by the rotation of a conveying roller 209. The conveying roller 209 is driven via a gear by an LF motor 213 as a drive source. It is determined whether the recording medium 208 has been fed and the position at the time of feeding is determined when the recording medium 208 passes a paper end sensor 214. The head cartridge 201 mounted on the carriage 202 is held so that the discharge port face protrudes downward from the carriage 202 and is parallel to the recording medium 208. The control unit 220 has a CPU or a storage means, etc., receives data for forming each of the above-mentioned layers from the outside, and controls the operation of each part of the recording device 111 based on the data.

[0022] [Recording device operation] The image recording operation in the recording device 111 will be described. The recording medium 208 in this embodiment is assumed to be a commonly used inkjet paper. First, when the recording medium 208 is transported to a predetermined recording start position, the carriage 202 moves on the recording medium 208 along the guide shaft 203, and each ink is discharged from the discharge port of the recording head during the movement. Then, when the carriage 202 moves to one end of the guide shaft 203, the transport roller 209 transports the recording medium 208 by a predetermined amount in a direction perpendicular to the main scanning direction of the carriage 202. In this embodiment, the transport of the recording medium 208 is called "paper feed" or "sub-scanning", and this transport direction is called "paper feed direction" or "sub-scanning direction". When the transport of the recording medium 208 by a predetermined amount is completed, the carriage 202 moves again along the guide shaft 203. In this manner, an image is recorded on the recording medium 208 by repeating the scanning and paper feed by the carriage 202 of the recording head.

[0023] 3A to 3B are diagrams illustrating the operation of recording an image by scanning a recording head over a recording medium 208. As shown in Fig. 3A to 3B, a layer is formed by the width L of the recording head in the main scan by the carriage 202, and the recording medium 208 is transported by a distance L in the sub-scanning direction each time recording of one line is completed.

[0024] In addition, in order to suppress deterioration of image quality such as periodic unevenness caused by the driving accuracy of the print head, so-called multi-pass printing may be performed. Figures 3(c) to 3(e) are diagrams showing an example of multi-pass printing in which the area to be printed is recorded in two scans (passes). In this example, a layer is formed by the width L of the print head by main scanning by the carriage 202, and the print medium 208 is transported in the sub-scanning direction by a distance L / 2 each time printing of one line is completed. Area A is printed by the mth main scan (Figure 3(c)) and the m+1th main scan (Figure 3(d)) of the print head, and area B is printed by the m+1th main scan (Figure 3(d)) and the m+2th main scan (Figure 3(e)) of the print head. In addition, it is possible to form a desired layer structure on the print medium by controlling the type of ink printed in each pass. For example, if printing is performed using fluorescent ink in the first pass and clear ink in the second pass, a layer structure of fluorescent ink in the lower layer and clear ink in the upper layer can be formed.

[0025] 3(c) to (e) show the operation of multi-pass printing with two passes (two-pass printing), but the number of passes in multi-pass printing can be changed according to the desired accuracy. For example, when performing n-pass printing with n passes, the printing medium 208 is transported in the sub-scanning direction by a distance L / n each time printing of one line is completed.

[0026] The recording medium 208 is not limited to paper, and various materials can be used as long as they are compatible with the formation of layers by the recording head.

[0027] FIG. 4 is a schematic diagram showing the expression of an image controlled by the area modulation method. For ease of explanation, the print head in this embodiment is controlled by a binary value of whether or not to eject ink droplets. In addition, in this embodiment, the on / off of printing by ink ejection is controlled for each pixel defined by the output resolution of the printing device 111, and the state in which all pixels in a unit area are turned on is treated as a state in which the ink printing amount is 100%. Note that "on" indicates that ink is ejected, and "off" indicates that ink is not ejected. In a printer in which ink ejection is controlled by such a binary value, the ink printing amount for a single pixel can only be expressed as 100% or 0%. For this reason, halftones are expressed by a set of multiple pixels.

[0028] In the example shown in FIG. 4, instead of expressing halftones at a density of 25% as shown in the lower left of FIG. 4, 4 black pixels out of 16 pixels (4×4 pixels) are set to ON and ink is ejected, as shown in the lower right of FIG. 4, to express 25% (4 / 16) in terms of area. Other gradations can be expressed in a similar manner. Note that the total number of pixels for expressing halftones, or the pattern of pixels that are turned ON, are not limited to the example in FIG. 4. The pattern of pixels that are turned ON can be determined using a periodic screen process called halftone dots, or an error diffusion process. Note that the above-mentioned binarization process can be extended to a multi-value process to modulate multiple levels, making it applicable to a print head that can modulate the amount of ink ejected, and is not limited to binarization.

[0029] [Ink composition] The components constituting each of the fluorescent ink, subtractive ink, and clear ink used in the recording apparatus 111 of this embodiment will be described below.

[0030] (aqueous medium) The ink used in this embodiment preferably uses an aqueous medium containing water and a water-soluble organic solvent. The content (mass%) of the water-soluble organic solvent in the ink is preferably 3.0% by mass or more and 50.0% by mass or less based on the total mass of the ink. The content (mass%) of water in the ink is preferably 50.0% by mass or more and 95.0% by mass or less based on the total mass of the ink.

[0031] Specifically, the water-soluble organic solvent may be, for example, the following: C1-6 alkyl alcohols, such as methanol, ethanol, propanol, propanediol, butanol, butanediol, pentanol, pentanediol, hexanol, and hexanediol; 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, having average molecular weights of 200, 300, 400, 600, and 1,000; alkylene glycols having an alkylene group with a carbon number of 2-6, such as ethylene glycol, 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; and glycerin. Lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether, etc. N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc. As for water, it is preferable to use deionized water (ion-exchanged water).

[0032] (Pigments) The pigment is preferably carbon black or an organic pigment. The content (mass %) of the pigment in the ink is preferably 0.1 mass % or more and 15.0 mass % or less based on the total mass of the ink.

[0033] The black ink preferably uses carbon black such as furnace black, lamp black, acetylene black, and channel black as a pigment. Specifically, the following commercially available products can be used: Rayvan: 7000, 5750, 5250, 5000ULTRA, 3500, 2000, 1500, 1250, 1200, 1190ULTRA-II, 1170, 1255 (all manufactured by Columbia); Black Pearls L, Regal: 330R, 400R, 660R, Mogul L, Monarch: 700, 800, 880, 900, 1000, 1100, 1300, 1400, 2000, Vulcan XC-72R (all manufactured by Cabot). Color black: FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex: 35, U, V, 140U, 140V, Special black: 6, 5, 4A, 4 (all manufactured by Degussa). No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, No. 2300, MCF-88, MA600, MA7, MA8, MA100 (all manufactured by Mitsubishi Chemical). In addition, carbon black newly prepared for this embodiment can be used. Of course, this embodiment is not limited to these, and any conventional carbon black can be used. In addition, it is not limited to carbon black, and magnetic fine particles such as magnetite and ferrite, titanium black, etc. may be used as a pigment.

[0034] Specific examples of the organic pigments that can be used include the following: Water-insoluble azo pigments such as toluidine red, toluidine maroon, Hansa yellow, benzidine yellow, and pyrazolone red; Water-soluble azo pigments such as lithol red, helio bordeaux, pigment scarlet, and permanent red 2B; Derivatives of vat dyes such as alizarin, indanthrone, and thioindigo maroon; Phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; Quinacridone pigments such as quinacridone red and quinacridone magenta; Perylene pigments such as perylene red and perylene scarlet; Isoindolinone pigments such as isoindolinone yellow and isoindolinone orange; Imidazolone pigments such as benzimidazolone yellow, benzimidazolone orange, and benzimidazolone red; Pyranthrone pigments such as pyranthrone red and pyranthrone orange. Indigo pigments, condensed azo pigments, thioindigo pigments, diketopyrrolopyrrole pigments, flavanthrone yellow, acylamide yellow, quinophthalone yellow, nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet, etc. Of course, the present embodiment is not limited to these.

[0035] In addition, when organic pigments are indicated by Color Index (CI) numbers, for example, the following can be used: CI Pigment Yellow: 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 97, 109, 110, 117, 120, 125, 128, 137, 138, 147, 148, 150, 151, 153, 154, 166, 168, 180, 185, etc. CI Pigment Orange: 16, 36, 43, 51, 55, 59, 61, 71, etc. CI Pigment Red: 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 175, 176, 177, 180, 192, etc. CI Pigment Violet: 19, 23, 29, 30, 37, 40, 50, etc. CI Pigment Blue: 15, 15:1, 15:3, 15:4, 15:6, 22, 60, 64, etc. CI Pigment Green: 7, 36, etc. CI Pigment Brown: 23, 25, 26, etc. Of course, the present embodiment is not limited to these.

[0036] (Fluorescent Dispersion) The fluorescent dispersion is a dispersion having fluorescent properties. For example, NKW-3207E (fluorescent pink water dispersion: Nippon Kinko Kagaku Co., Ltd.), NKW-3205E (fluorescent yellow water dispersion: Nippon Kinko Kagaku Co., Ltd.), etc. can be mentioned, but any dispersion having fluorescent properties will do.

[0037] (Dispersant) The dispersant for dispersing the above-mentioned pigment in the aqueous medium can be any water-soluble resin. In particular, the weight-average molecular weight of the dispersant is preferably 1,000 to 100,000, more preferably 3,000 to 15,000. The content (mass %) of the dispersant in the ink is preferably 0.1 to 5.0% by mass based on the total mass of the ink.

[0038] Specifically, the dispersant may be, for example, the following: A polymer having, as a monomer, styrene, vinyl naphthalene, an aliphatic alcohol ester of an α,β-ethylenically unsaturated carboxylic acid, acrylic acid, maleic acid, itaconic acid, fumaric acid, vinyl acetate, vinylpyrrolidone, acrylamide, or a derivative thereof. It is preferable that one or more of the monomers constituting the polymer is a hydrophilic monomer, and a block copolymer, a random copolymer, a graft copolymer, or a salt thereof may be used. Alternatively, a natural resin such as rosin, shellac, or starch may be used. It is preferable that these resins are soluble in an aqueous solution in which a base is dissolved, that is, are alkali-soluble.

[0039] (Surfactant) In order to adjust the surface tension of the inks constituting the ink set, it is preferable to use a surfactant such as an anionic surfactant, a nonionic surfactant, or an amphoteric surfactant, etc. Specifically, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenols, acetylene glycol compounds, acetylene glycol ethylene oxide adducts, etc. can be used.

[0040] (Other Ingredients) In addition to the above-mentioned components, the inks constituting the ink set may contain moisturizing solids such as urea, urea derivatives, trimethylolpropane, and trimethylolethane to maintain moisturizing properties. The content (mass%) of moisturizing solids in the ink is preferably 0.1% by mass or more and 20.0% by mass or less, and more preferably 3.0% by mass or more and 10.0% by mass or less, based on the total mass of the ink. In addition to the above-mentioned components, the inks constituting the ink set may contain various additives such as pH adjusters, rust inhibitors, preservatives, antifungal agents, antioxidants, reduction inhibitors, and evaporation promoters, as necessary.

[0041] Next, the ink used in this embodiment will be described in more detail. The present technology is not limited to this embodiment as long as it does not exceed the gist of the technology. In addition, "parts" and "%" in the text are based on mass unless otherwise specified.

[0042] (Preparation of Resin Aqueous Solution A) A styrene / acrylic acid random copolymer with an acid value of 200 mgKOH / g and a weight average molecular weight of 10,000 was neutralized with potassium hydroxide to 1 equivalent. Then, the resin concentration was adjusted to 10.0% with water to obtain an aqueous resin solution A.

[0043] (Preparation of Resin Aqueous Solution B) A random copolymer with an acid value of 288 mg KOH / g, weight average molecular weight of 10,000, and monomer composition of styrene / n-butyl acrylate / acrylic acid = 23 / 37 / 37 was neutralized with potassium hydroxide to 1 equivalent. Then, the resin concentration was adjusted to 10.0% with water to obtain a resin aqueous solution B.

[0044] (Preparation of Resin Aqueous Solution C) Acid value: 288 mg KOH / g, weight average molecular weight: 5,000, monomer composition: A random copolymer of styrene / n-butyl acrylate / acrylic acid = 23 / 37 / 37 was neutralized to 1 equivalent with potassium hydroxide. After that, the resin concentration was adjusted with water to 10.0%, and resin solution C was obtained. Resin solution C has a smaller molecular weight than resin solution B, so there are fewer surface irregularities and gaps during printing, and it has the effect of increasing the apparent refractive index. In addition to the molecular weight, a method of increasing the leveling properties of the ink can also be considered by adding 1,2 hexanediol to increase the ease with which the ink spreads.

[0045] (Preparation of Pigment Dispersions 1 to 4) Pigment dispersions 1 to 4 were prepared according to the following procedure.

[0046] "Preparation of pigment dispersion 1 containing CI Pigment Red 122" 10 parts of pigment (CI Pigment Red 122), 20 parts of resin aqueous solution A, and 70 parts of ion-exchanged water are mixed and dispersed for 3 hours using a batch-type vertical sand mill. After that, coarse particles are removed by centrifugation. Furthermore, the mixture is filtered under pressure using a cellulose acetate filter (manufactured by Advantec) with a pore size of 3.0 μm to obtain pigment dispersion 1 with a pigment concentration of 10% by mass.

[0047] "Preparation of pigment dispersion 2 containing CI Pigment Blue 15:3" 10 parts of pigment (CI Pigment Blue 15:3), 20 parts of resin aqueous solution A, and 70 parts of ion-exchanged water are mixed and dispersed for 5 hours using a batch-type vertical sand mill. After that, coarse particles are removed by centrifugation. Furthermore, the mixture is filtered under pressure using a cellulose acetate filter (manufactured by Advantec) with a pore size of 3.0 μm to obtain pigment dispersion 2 with a pigment concentration of 10% by mass.

[0048] "Preparation of pigment dispersion 3 containing CI Pigment Yellow 74" 10 parts of pigment (CI Pigment Yellow 74), 20 parts of resin aqueous solution A, and 70 parts of ion-exchanged water are mixed and dispersed for 1 hour using a batch-type vertical sand mill. After that, coarse particles are removed by centrifugation. Furthermore, the mixture is filtered under pressure using a cellulose acetate filter (manufactured by Advantec) with a pore size of 3.0 μm to obtain pigment dispersion 3 with a pigment concentration of 10% by mass.

[0049] "Preparation of pigment dispersion 4 containing CI Pigment Black 7" 10 parts of carbon black pigment (CI Pigment Black 7), 20 parts of resin aqueous solution A, and 70 parts of ion-exchanged water are mixed and dispersed for 3 hours using a batch-type vertical sand mill. The peripheral speed during dispersion is twice that during preparation of pigment dispersion 1. Then, coarse particles are removed by centrifugation. Furthermore, the mixture is filtered under pressure using a cellulose acetate filter (manufactured by Advantec) with a pore size of 3.0 μm to obtain pigment dispersion 4 with a pigment concentration of 10% by mass.

[0050] (Preparation of fluorescent dispersion liquid) Mix 10 parts of fluorescent pink water dispersion (NKW-3207E), 20 parts of resin aqueous solution A, and 70 parts of ion-exchanged water, and disperse using a homomixer, etc. Then, filter under pressure using a cellulose acetate filter (manufactured by Advantec) with a pore size of 3.0 μm to obtain a fluorescent dispersion liquid with a fluorescent dispersion concentration of 10% by mass.

[0051] (Ink Preparation) The components shown in Table 1 are mixed and thoroughly stirred. Then, the mixture is filtered under pressure using a cellulose acetate filter (Advantec) with a pore size of 0.8 μm to prepare the subtractive color inks CMYK, the fluorescent ink (P), the first clear ink (CL1), and the second clear ink (CL2).

[0052] [Table 1] The compositions of the first clear ink (CL1) and the second clear ink (CL2) are not limited to those described above. They are inks for controlling the deflection angle characteristics described below, and as long as they produce the same effect, the type of resin and the amount of resin added may be different.

[0053] [Characteristics of fluorescent inks and subtractive inks] Figure 5 is a graph in which the horizontal axis represents the wavelength of light and the vertical axis represents the reflectance (intensity), and shows the light intensity detected when the wavelength of the light irradiated on the recording sample and the wavelength of the light received from the sample are both changed.

[0054] The fluorescent component contained in the fluorescent ink is a coloring material that absorbs light of an excitation wavelength from a ground state, becomes excited, emits light of an emission wavelength, and returns to the ground state to develop color. The fluorescent pink ink that can be ejected by the recording head of the recording device 111 described above is also a fluorescent ink that uses such a fluorescent component.

[0055] Emission 502 represents the intensity of light received for each wavelength from a recording sample in which the fluorescent pink ink of this embodiment is recorded on a paper surface when the recording sample is irradiated with exciting light of a wavelength of 480 nm.

[0056] Excitation 501 represents the intensity of received light relative to the wavelength of light irradiated onto a recording sample recorded with the fluorescent pink ink of this embodiment, with the wavelength of the received light fixed at 600 nm.

[0057] As shown in Fig. 5, the wavelength range of excitation of fluorescent ink recorded on paper overlaps with the wavelength range of emission and is on the short wavelength side. Also, the excitation 501 has different strengths for each wavelength, indicating that there are wavelengths that emit light efficiently and wavelengths that do not. Also, since fluorescent ink emits light, the reflectance at the emission wavelength can exceed 1. In this embodiment, a component having such characteristics is defined as a fluorescent component.

[0058] As the characteristics of fluorescent ink, the excitation and emission of fluorescent pink ink adopted in the recording device 111 of the present embodiment have been described, but fluorescent inks emitting other wavelengths may be adopted in the recording device 111 of the present embodiment. Examples of such fluorescent inks include fluorescent blue inks emitting light in the blue region (450 nm to 500 nm) and fluorescent green inks emitting light in the green region (500 nm to 565 nm). In addition, fluorescent yellow inks emitting light in the yellow region (565 nm to 590 nm), and fluorescent orange or fluorescent red inks emitting light in the red region (590 nm to 780 nm) may be adopted. Furthermore, fluorescent inks combining the above-mentioned fluorescent inks may be adopted. Furthermore, fluorescent inks with different excitation wavelength intensities may be adopted with their color tones adjusted. Examples of fluorescent inks with their color tones adjusted include fluorescent pink inks that emit light in the orange region with weak excitation in the blue region and strong excitation in the green region.

[0059] In this embodiment, subtractive ink (also referred to as "color ink") is defined as ink containing color materials that absorb light of specific wavelengths and do not emit light when exposed to light. For example, the spectral reflectance of subtractive ink is the spectral reflectance of cyan (C) 503, magenta (M) 504, and yellow (Y) 505 in FIG. 5. Subtractive ink is different from fluorescent ink in that it only absorbs light and therefore the reflectance does not exceed 1.

[0060] [Angle deflection characteristics of fluorescent inks and subtractive inks] Figure 6 is a graph showing the deflection angle characteristics of each ink, including fluorescent ink (P) and subtractive color ink (M). The curves in the graph in Figure 6 represent the reflectance measured by irradiating light onto a print sample at an incident angle of 0° and varying the receiving angle. The reflectance can be measured, for example, using a JASCO spectrophotometer (V-770). The horizontal axis of the graph represents the receiving angle at the time of measurement, and the vertical axis represents the reflectance when the paper white is taken as 1.0.

[0061] As the graph in Figure 6 shows, the larger the light receiving angle when measuring the print sample, the higher the reflectance of the fluorescent ink (P) and the lower the reflectance of the colored ink (M). A larger light receiving angle when measuring corresponds to observing the print sample from a more oblique angle. The graph in Figure 6 shows that when observed from a more oblique angle, the fluorescent ink (P) appears brighter and the colored ink (M) appears darker.

[0062] Figure 7 is a schematic representation of the deflection angle characteristics shown in Figure 6. The solid line represents fluorescent ink, and the dashed line represents subtractive ink. Compared to the deflection angle characteristics of subtractive ink, the deflection angle characteristics of fluorescent ink scatter light isotropically. This is thought to be because fluorescent ink absorbs light, becomes excited, and emits light, losing the directionality of the incident light and becoming highly dependent on the directionality of the fluorescent ink's emission. These differences in deflection angle characteristics are modeled using the Bidirectional Reflectance Distribution Function, etc., and can be measured using commercially available BRDF measurement devices.

[0063] FIG. 8 is a diagram for explaining an example of an image defect caused by the difference in the deviation angle characteristics described above. FIG. 8(a) and (b) include a plan view showing the positional relationship between a printout, a light source incident on the printout at an incident angle of 0°, and an observer observing the printout, and an observation image showing the appearance of the printout observed under each condition. FIG. 8(a) is a diagram showing a plan view and an observation image when an observer observes a printout at a light receiving angle of 45°. FIG. 8(b) is a diagram showing a plan view and an observation image when an observer observes a printout at a light receiving angle of 75°. In the observation images of FIG. 8(a) and (b), surface A shows an area printed with fluorescent ink, and surface B shows an area printed with subtractive color ink.

[0064] The observation image in Figure 8(a) shows how the print appears when viewed almost directly from the front, and shows that side A and side B are viewed with almost the same brightness. In this way, when viewed in a normal environment, the print appears as an image without defects as envisioned by the print creator.

[0065] On the other hand, as the observation image in Figure 8(b) shows, when an observer views the print from an angle, side B recorded with colored inks appears darker than side A recorded with fluorescent inks. This is because, as shown in Figure 6, the deflection angle characteristics of the fluorescent ink (P) and colored inks (M) are different, so as the observation angle increases, the fluorescent ink (P) appears relatively brighter. In this way, when the deflection angle characteristics of each ink differ, the image may appear to have defects unintended by the creator, such as a loss of gradation and color balance depending on the observation angle.

[0066] For printed matter that is viewed by an unspecified number of people, such as advertising posters, there is a demand to reduce the number of viewing conditions under which the image intended by the creator cannot be presented. In other words, there is a demand to record an image so that the gradation and color balance of the image are not lost even when the image is viewed from an oblique angle. Therefore, in this embodiment, a method is described for suppressing the difference in the deflection characteristics between the fluorescent ink recording area and the color ink recording area by using two clear inks with different deflection characteristics.

[0067] [Controlling deflection angle characteristics with clear ink] The deflection characteristics of the first clear ink (CL1) and second clear ink (CL2) used in this embodiment will be described. In the graph of Figure 6, CL1 indicates the deflection characteristics of the first clear ink, and CL2 indicates the deflection characteristics of the second clear ink.

[0068] The first clear ink (CL1) is an ink with a high refractive index. Considering the behavior of light that passes through the ink layer and travels to the air layer, the angle of incidence and angle of emission (angle of refraction) change according to the ratio of the refractive indexes of the ink and air. This behavior is known as Snell's law. The higher the refractive index of the ink, the narrower the critical angle, which is the angle at which light can exit the ink layer into the air layer, and it is thought that less light is emitted in an oblique direction (the direction with the larger light receiving angle in Figure 6) (hereinafter, this state will also be referred to as "low isotropy"). Conversely, the refractive index of the second clear ink (CL2) is relatively low compared to the other inks. For this reason, relatively more light is emitted in an oblique direction (hereinafter, this state will also be referred to as "high isotropy").

[0069] Isotropy can be expressed as the ratio of features that indicate the brightness at two different observation angles. For example, when the incident angle of the light source is 0° and the receiving angle during observation is 75° (incident angle 0°, receiving angle 75°), the brightness is expressed as Y 0-75 When the incident angle of the light source is 0° and the receiving angle during observation is 45° (incident angle 0°, receiving angle 45°), the luminance is defined as Y 0-45 The unit of luminance is, for example, [cd / m 2 ]. And R=Y 0-75 / Y 0-45 The degree of isotropy can be evaluated by the ratio R obtained from

[0070] A large ratio R indicates that there is a lot of light emitted in an oblique direction, and thus indicates high isotropy. A small ratio R indicates that there is little light emitted in an oblique direction, and thus indicates low isotropy. Note that the degree of isotropy may be expressed using other characteristic quantities, such as brightness or density, that take into account human visual sensitivity, in addition to luminance.

[0071] In this embodiment, the luminance at an incidence angle of 0° and an acceptance angle of 75° and the luminance at an incidence angle of 0° and an acceptance angle of 45° are measured, and the ratio R is used as a numerical value for evaluating the degree of isotropy. It is also possible to evaluate the degree of isotropy using other incidence angles and acceptance angles.

[0072] In addition to the refractive index, another factor that affects the deflection angle characteristics is the unevenness of the ink layer surface. If the surface is smooth, the light behaves similarly to an ideal interface, and the emission angle is limited by the influence of the critical angle and other factors mentioned above. In other words, isotropy becomes relatively small. On the other hand, if the surface is rough, the surface normals will point in various directions if considered as a microscopic surface. For this reason, the critical angle does not have much influence, and light appears to be diffused macroscopically. In other words, there is a relatively large amount of light that is emitted in an oblique direction, and isotropy becomes large.

[0073] By utilizing these characteristics and using colored inks or fluorescent inks and clear inks with different deflection angle characteristics, it is possible to control the magnitude of isotropy in the area recorded with colored inks or fluorescent inks. For example, by overcoating a first clear ink (CL1) on the fluorescent ink recorded area recorded with fluorescent ink (P) shown in FIG. 6, it is possible to reduce the light emitted in an oblique direction. In addition, the increase or decrease of light can be controlled by stochastically coating the clear ink using area gradation. This makes it possible to control, for example, the magnitude of isotropy in the fluorescent ink recorded area so that it is approximately the same as the magnitude of isotropy in the colored ink recorded area, which is an area recorded with colored ink (M).

[0074] FIG. 9 is a diagram showing the measurement results of samples obtained by the recording device 111 of this embodiment. Each of the samples No. 1 to No. 9 was obtained by filling an ink cartridge with each of the inks in Table 1 and recording with an inkjet recording device equipped with a recording head that ejects ink by thermal energy. The inkjet recording device used was a Canon product called "PIXUS PRO-10S." An image recorded with this inkjet recording device under the condition that four drops of 3.8ng±10% ink are applied to a unit area of ​​1 / 600 inch×1 / 600 inch is defined as having a recording duty of 100%. The recording medium used was a Canon product called "Canon Photo Paper Premium Matte PM101."

[0075] Fig. 9(a) is a table summarizing the ink amount, luminance at an incidence angle of 0° and a receiving angle of 75°, luminance at an incidence angle of 0° and a receiving angle of 45°, normalized luminance at each receiving angle of 75° and 45°, and the ratio R for each sample. The ratio R is a value calculated using the normalized luminance at an incidence angle of 0° and a receiving angle of 75° as the numerator and the normalized luminance at an incidence angle of 0° and a receiving angle of 45° as the denominator. The normalized luminance is the luminance value when the luminance observed at the same receiving angle for paper white (sample No. 1) is set to 1.000.

[0076] The numerical value written for the ink amount in Figure 9(a) is the aforementioned print duty conversion value [%]. In terms of ink amount, there is a sample in which the ink amount of the fluorescent ink (P) or colored ink (M) and the first clear ink (CL1) or second clear ink (CL2) is greater than 0. This sample indicates a sample generated by printing after overcoating the first clear ink (CL1) or second clear ink (CL2) on an area printed with the fluorescent ink (P) or colored ink (M).

[0077] The luminance when the light source is incident at an incident angle of 0° and received at an acceptance angle of 75° (incident angle 0°, acceptance angle 75°) and the luminance when the light source is incident at an incident angle of 0° and received at an acceptance angle of 45° (incident angle 0°, acceptance angle 45°) are values ​​measured using a spectrophotometer V-770 manufactured by JASCO. This measured luminance is a value when the luminance when the light source is incident at an incident angle of 0° and measured at an acceptance angle of 180°, that is, the luminance when the incident light itself is measured, is set to 1.0. The ratio R is an evaluation value that indicates the degree of isotropy of the deviation angle characteristics. A large ratio R indicates that more light is emitted in an oblique direction, indicating high isotropy. A small ratio R indicates that less light is emitted in an oblique direction, indicating low isotropy.

[0078] FIG. 9(b) is a bar graph showing the values ​​of the ratio R for samples Nos. 1, 2, 3, 6, and 7 shown in FIG. 9(a).

[0079] Sample No. 2 is a sample recorded using only fluorescent ink (P), and sample No. 3 is a sample recorded using only colored ink (M), and is a sample recorded in a clear ink-free mode described below. As shown in Figure 9(b), there is a large difference in the ratio R between sample No. 2 and sample No. 3, indicating a large difference in the magnitude of isotropy between the fluorescent ink (P) and colored ink (M). Comparing the values ​​of samples No. 2 and No. 3 shown in Figure 9(a), the luminance at a light receiving angle of 45° is almost the same, but there is a difference in the luminance at a light receiving angle of 75°, resulting in a large difference in the ratio R.

[0080] Sample No. 6 is a sample printed in clear ink mode, and was obtained by overcoating an area recorded with fluorescent ink (P) with a first clear ink (CL1) in an ink amount of 70. The ratio R of sample No. 6 is smaller than the ratio R of sample No. 2, which was recorded with fluorescent ink (P) only, and is closer to the ratio R of paper white. In other words, this shows that the isotropy is reduced by overcoating the first clear ink (CL1), approaching the magnitude of the isotropy of paper white.

[0081] Sample No. 7 is a sample printed in a clear ink mode, and was obtained by overcoating the areas where colored inks were printed with a second clear ink (CL2) with an ink amount of 20. Sample No. 7 has a larger ratio R value than sample No. 3, which was printed with colored inks only, and is closer to the ratio R of the paper white. In other words, this shows that the isotropy has increased by overcoating the second clear ink (CL2), approaching the magnitude of the isotropy of the paper white.

[0082] FIG. 10 is a schematic diagram showing the deflection angle characteristics of each ink, i.e., color ink, fluorescent ink, first clear ink, and second clear ink, or the deflection angle characteristics of a combination of each ink. In FIG. 10, the length of the arrow indicates the brightness of the reflected light. The reflectance, i.e., the brightness at an incident angle of 0° and a receiving angle of 0°, differs greatly between color ink, fluorescent ink, and clear ink. However, it should be noted that FIG. 10 is normalized to illustrate the change in deflection angle characteristics due to the change in observation angle for each ink type. That is, the vertical arrows in FIG. 10(a) are the same length because, for comparison, the illustration shows the same brightness recorded with each ink.

[0083] Figure 10(a) shows the deflection angle characteristics of each ink alone, and since the degree of isotropy differs depending on the ink, the size of the diagonal arrow differs for each ink type. Figure 10(a) shows that, from greatest isotropy, it is second clear ink (CL2) > fluorescent ink (P) > colored ink (M) > first clear ink (CL1). Note that the degree of isotropy of each color ink, C, M, Y, and K, is approximately the same. The deflection angle characteristics can be ascertained by measuring samples obtained by printing each ink on a printing medium in advance at multiple light receiving angles as described above. Figure 10(b) will be discussed later.

[0084] [Functional configuration of image processing device] 11 is a diagram showing the functional configuration of the image processing device 1 in this embodiment. The image processing device 1 has a first image acquisition unit 1101, a color ink amount determination unit 1102, a second clear ink amount determination unit 1103, a second image acquisition unit 1104, a fluorescent ink amount determination unit 1105, a first clear ink amount determination unit 1106, and a print data generation unit 1107. It also has an output unit 1108.

[0085] The first image acquisition unit 1101 acquires first image data in which signal values ​​corresponding to color inks are pixel values. The second image acquisition unit 1104 acquires second image data in which signal values ​​of a color for fluorescent ink used as a special spot color are pixel values. The color ink amount determination unit 1102 determines the amount of color ink for each pixel from the first image data. The fluorescent ink amount determination unit 1105 determines the amount of fluorescent ink for each pixel from the second image data. The second clear ink amount determination unit 1103 determines the ink amount of second clear ink for each pixel. The first clear ink amount determination unit 1106 determines the ink amount of first clear ink for each pixel.

[0086] The print data generation unit 1107 performs binarization processing on the data of the determined color ink amounts, fluorescent ink amount, first clear ink amount, and second clear ink amount. The print data generation unit 1107 then generates print data that represents the on and off state of each ink in each pixel. The output unit 1108 outputs the print data to the printing device 111. The printing device 111 prints an image based on the print data.

[0087] Each functional unit in the image processing device 1 in Fig. 11 is realized by the CPU 101 executing a predetermined program, but is not limited to this. For example, other hardware such as a GPU (Graphics Processing Unit) or an FPGA (Field Programmable Gate Array) for accelerating calculations may be used. Each functional unit may be realized by cooperation between software and hardware such as a dedicated IC, or some or all of the functions may be realized only by hardware.

[0088] [Processing flow] Fig. 12 is a flowchart showing the flow of processing in this embodiment up to the point where the image processing device 1 outputs recording data, which is data for image recording by the recording device 111. The processing in each step in Fig. 12 is performed by the CPU 101 of the image processing device 1 expanding the program code stored in the ROM 102 into the RAM 103 and executing it. Alternatively, some or all of the functions of the steps in Fig. 12 may be realized by hardware such as an ASIC or an electronic circuit. The symbol "S" in the explanation of each process indicates that it is a step in the flowchart.

[0089] It is assumed that the image processing device 1 stores data of an image to be recorded to be recorded by the recording device 111. The data of the image to be recorded is data obtained by, for example, using an image generation application to design graphics using a special color pink as a spot color. It is assumed that the special color pink plate is designed using a layer separate from the RGB layers. It is assumed that the data of the image to be recorded is separated to generate data of an RGB image, which is the first image data, and second image data for fluorescent ink (P).

[0090] Furthermore, the image generation application has an attribute called overprint, which controls whether or not to print the underlying object when objects overlap. By default, only the upper object is printed, and processing is generally performed in which the paint information of the lower object is not reflected. Also, when image data in which objects overlap is received, it is possible to set the image processing device 1 not to overprint. In this embodiment, the data of the image to be recorded is such that the pixel values ​​of each pixel are maintained in the recording area to be recorded with fluorescent ink (P) so that recording with CMYK color inks is not performed.

[0091] In S1201, the first image acquisition unit 1101 acquires, from an external device such as the HDD 113, first image data generated from data of an image to be recorded.

[0092] The first image data is RGB image data having RGB values, which are pixel values, for each pixel. The RGB values ​​are 48-bit values ​​consisting of 16-bit signal values ​​for the R (red), G (green), and B (blue) values ​​corresponding to each RGB color. The pixel value of a pixel at position (x, y) is represented as RGB(x, y). Position (x, y) indicates the pixel position in the image when the horizontal coordinate of the pixel is x and the vertical coordinate of the pixel is y.

[0093] In the present embodiment, the first image data is described as image data whose pixel values ​​are RGB values ​​defined in the sRGB space. As the first image data, other image data such as an RGB image defined by the commonly used AdobeRGB, a Lab image corresponding to CIELAB, or an HSV image consisting of hue, saturation, and brightness may be used.

[0094] In S1202, the color ink amount determination unit 1102 determines the color ink amount CMYK(x,y) which is the ink amount of the color ink of CMYK at the position (x,y) from the first image data. A general method such as using a lookup table (LUT) in which RGB and CMYK are associated in advance can be used to determine the color ink amount. In addition, color conversion for color management or the like may be performed as appropriate as pre-processing. The color ink amount CMYK(x,y) is data composed of signal values ​​for each ink color of C, M, Y, and K, and the signal values ​​are described as density values ​​with 8 bits (0 to 255) for each gradation. Note that the value indicating the ink amount is an example and may be expressed with other bit numbers or as a percentage.

[0095] In S1203, the second image acquisition unit 1104 acquires second image data generated from data of the image to be recorded from an external device such as the HDD 113. The second image data is an image for fluorescent ink used as a special spot color, and is an image in which the pixel value for each pixel position (x, y) is a 16-bit P (special pink) value. In the second image data, the pixel value at position (x, y) is represented as P(x, y).

[0096] As described above, in this embodiment, the recording area of ​​pixel value P and the recording area of ​​pixel values ​​CMYK are exclusive. That is, at a certain position (x, y), there is no case where CMYK(x, y)>0 and P(x, y)>0.

[0097] In S1204, the fluorescent ink amount determination unit 1105 determines the fluorescent ink amount P'(x,y), which is the ink amount of fluorescent ink, by performing gamma correction on the pixel value P(x,y) of the second image data. The signal value of P'(x,y) is assumed to be a density value with each gradation being 8 bits (0 to 255), similar to CMYK(x,y).

[0098] In S1205, the print data generation unit 1107 determines whether or not clear ink is to be used to print an image in the printing device 111. If the print data generation unit 1107 determines that clear ink is to be used (YES in S1205), the process proceeds to S1206. If the print data generation unit 1107 determines that clear ink is not to be used (NO in S1205), the process skips S1206 and S1207 and proceeds to S1208.

[0099] The recording device 111 of this embodiment is configured to be able to set either a "mode with clear ink" or a "mode without clear ink" as the recording mode. The mode selected by the user is set by manually selecting either the "mode with clear ink" or the "mode without clear ink". If the "mode with clear ink" is set, it is determined in S1205 that clear ink will be used. If the "mode without clear ink" is set, it is determined that clear ink will not be used.

[0100] Alternatively, it may be determined whether or not to use clear ink regardless of the user's selection. For example, the sum of the fluorescent ink amounts P'(x,y) at all positions in the image is calculated. If fluorescent ink is not used, the calculation result will be zero, so if the sum of the fluorescent ink amounts P'(x,y) is zero, it may be determined that clear ink is not to be used. Also, if the sum of the fluorescent ink amounts P'(x,y) is not zero, it may be determined that clear ink is to be used.

[0101] In S1206, the second clear ink amount determination unit 1103 calculates the ink amount CL2(x, y) of the second clear ink to be recorded at the position (x, y) using formula (1). The signal value indicating the ink amount CL2(x, y) will also be described as an 8-bit (0 to 255) density value.

[0102] if CMYK(x,y)>0, CL2(x,y)=a else CL2(x,y)=0 Eq.(1) In formula (1), CMYK(x,y)>0 indicates that CMYK(x,y)>0 if the ink amount (signal value) of any of the C, M, Y, and K inks is greater than 0. For this reason, printing is performed with the second clear ink at a position (x,y) that has been printed with any of the C, M, Y, and K color inks, and the ink amount CL2(x,y) of the second clear ink during this printing is determined.

[0103] Furthermore, when CMYK(x,y)>0 is not satisfied in formula (1), that is, when the else in formula (1) is satisfied, it is when P'(x,y)>0, or when CMYK(x,y)=0 and P'(x,y)=0. When CMYK(x,y)=0 and P'(x,y)=0 are satisfied, the position (x,y) is a paper white position where no ink is recorded.

[0104] The value a of the ink amount CL2(x,y) of the second clear ink in formula (1) is a preset constant, and the value a may be determined in advance so that the magnitude of isotropy of the color ink and the fluorescent ink is close to each other. For example, as shown in the measurement result in FIG. 9A, when the ink amount of the second clear ink is 20% in terms of the print duty conversion value, the isotropy of the color ink approaches paper white. Therefore, the value a in formula (1) may be determined so as to be a value corresponding to a print duty conversion value of 20%. For example, if it is assumed that the signal value of 256 gradations and the ink amount have a linear relationship, the ink amount in FIG. 9A is described on the assumption that the ink is applied up to 300%, so the value a is determined as 255×(20 / 300)=17. This numerical value is a value for explaining this embodiment, and since the relationship between the signal value and the print duty conversion value differs for each product, it may be determined in advance according to the product.

[0105] In S1207, the first clear ink amount determination unit 1106 calculates the ink amount CL1(x,y) of the first clear ink to be recorded at the position (x,y) using formula (2). The first clear ink is recorded at the position (x,y) recorded with the fluorescent ink, and the ink amount CL1(x,y) of the first clear ink during this recording is determined. The signal value indicating the ink amount CL1(x,y) of the first clear ink is also an 8-bit (0 to 255) density value.

[0106] if P'(x,y)>0, CL1(x,y)=b else CL1(x,y)=0 Equation (2) A case in which P'(x,y)>0 in formula (2) is not satisfied, i.e., a case in which "else" in formula (2) is satisfied, is a case in which CMYK(x,y)>0 or a case in which CMYK(x,y)=0 and P'(x,y)=0.

[0107] The value b of the ink amount CL1 of the first clear ink in formula (2) is a preset constant, which may be determined in advance so that the magnitude of isotropy of the colored inks and the fluorescent ink is close to that of the white paper. For example, as shown in the measurement result in Figure 9(a), when the ink amount of the first clear ink is 70% in terms of the print duty conversion value, the magnitude of isotropy of the fluorescent ink is close to that of the white paper. Therefore, the value b in formula (2) may be set to a value corresponding to a print duty conversion value of 70%.

[0108] In this embodiment, the values ​​a and b indicating the ink amount are described as constants. By overcoating the clear ink, the resin component in the clear ink covers the surface of the color ink or fluorescent ink, changing the refractive index and unevenness of the surface. Under the above-mentioned measurement conditions (recording medium, ink, etc.), the surface state due to the clear ink is affected to some extent by the amount of the CMYK color ink or fluorescent pink ink applied as the base, but the change is mainly due to the amount of clear ink. This is thought to be because the layer of clear ink acts like a filter. Therefore, even if the amount of clear ink is a constant, the effect of aligning the magnitude of isotropy can be obtained.

[0109] In S1208, the print data generation unit 1107 performs binarization processing on the determined color ink amount CMYK(x,y) data and fluorescent ink amount P'(x,y) data, respectively, to generate print data for each ink. If the processes of S1206 and S1207 have been performed, binarization processing is also performed on the ink amount CL1(x,y) of the first clear ink and the ink amount CL2(x,y) of the second clear ink, respectively, to generate print data for each clear ink. As described in FIG. 4, the print data is data that represents the ink on or off state at each pixel. The same method for generating print data from ink amount data may be used for each ink.

[0110] The output unit 1108 outputs the recording data to the recording device 111. The recording device 111 records an image on a recording medium based on the received recording data.

[0111] For example, suppose that after the processing of S1206 and S1207, the process proceeds to S1208, print data is generated in S1208, and an image is printed by the printing device 111 based on the generated print data. In this case, in the first embodiment, the areas printed with the CMYK color inks are overcoated with the second clear ink. The areas printed with the fluorescent ink (P) are overcoated with the first clear ink. The white paper is not overcoated with clear ink. Note that the amount of clear ink may be determined in S1206 or S1207 so that either the first clear ink or the second clear ink is printed on the white paper.

[0112] Fig. 10(b) is a schematic diagram showing the effect of this embodiment. The fluorescent ink (P) has relatively high isotropy compared to the colored inks (M). For this reason, the fluorescent ink (P) printed area is overcoated with a first clear ink (CL1) having low isotropy. Moreover, the colored ink (M) printed area is overcoated with a second clear ink (CL2) having high isotropy. By printing in this manner, the degree of isotropy of the colored ink printed area and the fluorescent ink printed area can be made close to each other.

[0113] In multi-pass printing, overcoating is performed by recording with color ink or fluorescent ink in the first pass, and then recording with clear ink in the second pass.

[0114] Alternatively, printing may be performed with clear ink in the first pass, and with colored ink or fluorescent ink in the second pass. For example, if the main component of the clear ink is a solid resin, applying the clear ink in the first pass leaves the solid component on the recording medium. If the colored ink or fluorescent ink applied in the second pass passes through the solid component and the color material is fixed within the recording medium, an image structure that looks like a clear ink overcoat will be formed, regardless of the order of the inks.

[0115] Also, the degree of isotropy of the color ink recording area and the fluorescent ink recording area may be made closer to each other by recording so that the fluorescent ink is mixed with a first clear ink having low isotropy and the color ink is mixed with a second clear ink having high isotropy. A method of recording so that the inks are mixed is, for example, a method of multi-pass recording in which recording is performed in two passes, in which the second clear ink is applied after the color ink in the first pass. Similarly, in the second pass, the second clear ink is applied after the color ink to form a multi-layer structure. When the interval at which the color ink and the second clear ink land on the recording medium becomes small, the inks can be made to be substantially mixed on the recording medium.

[0116] As described above, according to this embodiment, the deflection characteristics can be controlled by using clear ink for color inks and fluorescent inks having different deflection characteristics (magnitude of isotropy). This allows the deflection characteristics of the color ink recorded area and the fluorescent ink recorded area to be brought closer together. This allows the degree of change in brightness of the color ink recorded area and the fluorescent ink recorded area in a printed matter when the observation angle (light receiving angle) is changed to be brought closer together. This makes it possible to suppress image defects in printed matter such as tone inversion and color balance loss when the observation angle is changed.

[0117] The deflection angle characteristics of the printing area of ​​each ink are affected by the unevenness of the base or the unevenness of the ink layer thickness, and therefore also vary depending on the type of printing medium. For this reason, the amount of clear ink may be changed for each type of printing medium.

[0118] Furthermore, the ink amount value a of the first clear ink and the ink amount value b of the second clear ink may be changed based on the respective areas of the fluorescent ink recording area and the colored ink recording area. By increasing the amount of clear ink corresponding to a recording area with a small area, it is expected that the total consumption of the first clear ink and the second clear ink will be reduced.

[0119] <Embodiment 2> In the first embodiment, a method for suppressing the influence of the ink deflection characteristics (isotropy) on printed matter using two types of clear ink was described. In this embodiment, a method for suppressing the influence of the ink deflection characteristics (isotropy) using one type of clear ink will be described. This embodiment will be described focusing on the differences from the first embodiment. Portions that are not specifically stated have the same configuration and processing as the first embodiment.

[0120] [Logical configuration of image processing device] Fig. 13 is a diagram showing the logical configuration of the image processing device 1 in this embodiment. The same components as those in Fig. 11 are given the same reference numerals and will not be described in detail.

[0121] The image processing apparatus 1 has a first image acquisition unit 1101 , a color ink amount determination unit 1102 , a second image acquisition unit 1104 , a fluorescent ink amount determination unit 1105 , a clear ink amount determination unit 1301 , a print data generation unit 1107 , and an output unit 1108 .

[0122] A clear ink amount determination unit 1301 determines the amount of clear ink to be applied to each of an area printed with CMYK color inks and an area printed with fluorescent ink (P).

[0123] [Processing flow] FIG. 14 is a flowchart showing the flow of processing in this embodiment from when the image processing device 1 generates print data to when it outputs the print data.

[0124] Since S1401 to S1404 are similar to S1201 to S1204, the description thereof will be omitted.

[0125] In S1405, the clear ink amount determination unit 1301 determines the amount of clear ink CL(x, y) when recording at the position (x, y).

[0126] In this embodiment, the clear ink used by the recording device 111 is either a first clear ink or a second clear ink. The ink amount of the clear ink determined in S1405 is determined by the relative magnitude of the isotropy of the clear ink used by the recording device 111.

[0127] The ratio that indicates the degree of isotropy of the fluorescent ink is R P , the ratio indicating the degree of isotropy of the color ink is R CMYK , the ratio indicating the degree of isotropy of the clear ink installed in the recording device 111 is R CL In the case where the isotropy of the clear ink used in the recording device 111 is smaller than that of the other inks, that is, R P >R CMYK >R CL In this case, the ink amount CL(x, y) of the clear ink is calculated based on the formula (3). As described above, the ratio R is R=Y 0-75 / Y 0-45 It is calculated by Y 0-45 is the luminance measured at an incident angle of 0° and an acceptance angle of 45°, and Y 0-75 is the luminance measured at an incident angle of 0° and a receiving angle of 75°. In other words, if the clear ink used in the recording device 111 is the first clear ink, the ink amount CL(x, y) of the clear ink is calculated based on formula (3). The first clear ink corresponds to the clear ink used when forming sample No. 8 in FIG. 9(a). It is assumed that the fluorescent ink is more isotropic than the CMYK colored inks.

[0128] if P'(x,y)>0, CL(x,y)=a else CL(x,y)=b Eq.(3) In formula (3), a>b, and b may be 0. Formula (3) indicates that more clear ink is applied to areas recorded with fluorescent ink, which has high isotropy, than to other areas (white paper or colored ink recorded areas).

[0129] Suppose that image data is input that contains a mixture of fluorescent ink recording areas recorded with the fluorescent ink in the amount used to generate sample No. 2 in Figure 9(a) and colored ink recording areas recorded with the colored ink in the amount used to generate sample No. 3. In this case, recording data is generated such that the first clear ink (CL1), which has low isotropy, is applied in larger amounts to the fluorescent ink recording areas than to the colored ink recording areas.

[0130] Fig. 15(c) is a schematic diagram showing the effect of this process. As mentioned above, the isotropy of the first clear ink (CL1) is relatively small, so when an appropriate amount of the first clear ink (CL1) is overcoated onto the fluorescent ink (P) printed area, the isotropy of the fluorescent ink (P) printed area can be reduced. This makes it possible to bring the magnitude of the isotropy of the entire printed matter closer to the isotropy of the colored ink (M).

[0131] Fig. 15(a) is a bar graph showing the values ​​of the ratio R for samples No. 2, 3, and 4 shown in Fig. 9(a). Sample No. 4 was obtained by overcoating sample No. 2 with a first clear ink (CL1) at an ink volume equivalent to a print duty of 120%. Compared to sample No. 2, which was printed only with fluorescent ink (P), which has high isotropy, sample No. 4 shows that the magnitude of isotropy is almost the same as that of colored ink (M).

[0132] If b=0 in formula (3), the isotropy of the fluorescent ink recording area and the color ink recording area will be almost the same, so the degree of change in brightness due to changes in the observation angle of both areas will be the same, and image defects such as tone inversion and color balance loss can be suppressed. When b=0, the value a in formula (3) can be determined to be a value corresponding to a print duty conversion value of 120% so as to obtain the state of sample No. 4. Note that the value a in formula (3) may be determined as an ink amount less than the ink amount shown in the example. Even with a small amount of clear ink, the difference in isotropy is reduced, and the effect of suppressing image defects can be obtained.

[0133] Furthermore, for example, there may be cases where it is desired to apply clear ink to the colored ink recording area and the white paper for reasons such as abrasion resistance. In such cases, b>0 may be set in formula (3) so that the first clear ink is also applied to the colored ink recording area. When b>0 is set in formula (3), the value a is set to be larger than when b=0, and the amount of the first clear ink applied to the fluorescent ink area is increased, thereby narrowing the difference in isotropy between the two areas. In this case, the values ​​a and b may be determined in advance so that the isotropy of the colored ink and the fluorescent ink are close to each other.

[0134] On the other hand, when the isotropy of the clear ink used in the recording device 111 is greater than that of the other inks, that is, when R CL >R P >R CMYK If so, in S1405, the ink amount CL(x, y) of the clear ink is calculated based on formula (4). In other words, if the clear ink used in the recording device 111 is the second clear ink, the ink amount CL(x, y) of the clear ink is calculated based on formula (4). The second clear ink corresponds to the clear ink used when forming sample No. 9 in FIG. 9(a).

[0135] if CMYK(x,y)>0, CL(x,y)=a else CL(x,y)=b Eq.(4) In formula (4), a>b, and b may be 0. Formula (4) indicates that areas printed with colored inks having low isotropy are printed with more clear ink than other areas (paper white or fluorescent ink printed areas).

[0136] Fig. 15(d) is a schematic diagram showing the effect of this process. As mentioned above, the isotropy of the second clear ink (CL2) is relatively large, so when an appropriate amount of the second clear ink (CL2) is applied to the colored ink (M) recording area, the isotropy of the colored ink (M) recording area can be increased. This makes it possible to bring the magnitude of the isotropy of the entire printed matter closer to that of the fluorescent ink (P).

[0137] Fig. 15(b) is a bar graph showing the values ​​of the ratio R for samples No. 2, 3, and 5 shown in Fig. 9(a). Sample No. 5 was obtained by overcoating sample No. 3 with a second clear ink (CL2) at an ink volume equivalent to a print duty of 40%. Sample No. 5 shows that it has almost the same isotropy as fluorescent ink (P) compared to sample No. 3, which was printed only with colored ink (M), which has low isotropy.

[0138] When b=0 in formula (4), the value a in formula (4) may be previously determined to be a value corresponding to a print duty conversion value of 40%. Alternatively, as in the case where the first clear ink is installed, an ink amount less than the ink amount shown as an example may be determined. When b>0 in formula (4), the value a may be determined to be greater than when b=0.

[0139] S1406 is the same process as S1208, and the print data generation unit 1107 generates print data for each ink. That is, binarization is performed on the determined color ink amount CMYK(x,y) data, fluorescent ink amount P'(x,y) data, and ink amount CL(x,y) of the installed clear ink, to generate print data for each ink. The output unit 1108 outputs the print data to the printing device 111. The printing device 111 prints an image based on the received print data.

[0140] Note that the flowchart in Fig. 14 may include a step of determining whether or not clear ink is to be used for recording an image, like S1205 in Fig. 12. Then, if it is determined that clear ink is to be used, S1405 may be performed.

[0141] As described above, according to this embodiment, by applying one type of clear ink to areas printed with colored ink and fluorescent ink having different deflection angle characteristics, it is possible to control the deflection angle characteristics of the printed matter to be the same. In other words, according to this embodiment, the degree of brightness change between the colored ink printed area and the fluorescent ink printed area when the observation angle is changed becomes closer, so that image defects such as tone inversion and color balance loss when the observation angle is changed can be suppressed.

[0142] In this embodiment, the clear ink used in the recording device 111 is the first clear ink or the second clear ink, and the isotropy of the clear ink has been described as being smaller or larger than both the colored ink and the fluorescent ink. Alternatively, the clear ink used in the recording device 111 may be a clear ink different from the first clear ink and the second clear ink, and may have an isotropy between the isotropy of the colored ink and the fluorescent ink.

[0143] In this case, the ink amount CL(x, y) of the clear ink can be determined by using the value of the ratio R, which indicates the magnitude of the isotropy of each ink. For example, the ratio R of the clear ink CL and the fluorescent ink ratio R P The difference betweenCL -R P ) is the ratio of clear ink R CL and the color ink ratio R CMYK The difference between CL -R CMYK The amount of clear ink can be determined depending on whether the amount of clear ink is greater than (R CL -R P )>(R CL -R CMYK ), the ink amount CL(x, y) of the clear ink should be determined based on formula (3) so that a large amount of clear ink is applied to the fluorescent ink (P) printing area. CL -R P )<(R CL -R CMYK In this case, the ink amount CL(x,y) of the clear ink can be determined based on formula (4) so ​​that a large amount of clear ink is applied to the CMYK color ink recording area. By applying a large amount of clear ink to the recording area of ​​the ink that is farther away from the clear ink that is installed, it is expected that the magnitude of the overall isotropy can be made uniform efficiently.

[0144] <Embodiment 3> In the above-described embodiment, a method for determining the ink amount of clear ink depending on the fluorescent ink recording area and the colored ink recording area has been described. In this embodiment, a method for determining an appropriate ink amount of clear ink is described, taking into consideration differences in deflection angle characteristics due to ink amount at each position in an image. This embodiment will be described focusing on the differences from the first embodiment. Portions not specifically mentioned have the same configuration and processing as the first embodiment.

[0145] [Logical configuration of image processing device] Fig. 16 is a diagram showing the logical configuration of the image processing device 1 in this embodiment. The same components as those in Fig. 11 are given the same reference numerals and will not be described in detail. The image processing device 1 has an image acquisition unit 1601, a color ink amount / fluorescent ink amount determination unit 1602, a target deflection angle characteristics determination unit 1603, a clear ink amount determination unit 1604, a print data generation unit 1107, and an output unit 1108.

[0146] An image acquisition unit 1601 acquires image data. A color ink amount / fluorescent ink amount determination unit 1602 determines the ink amounts of each color ink of CMYK and fluorescent ink from the image data. A target deflection angle characteristic determination unit 1603 determines the target deflection angle characteristics for all pixels in the image. A clear ink amount determination unit 1604 determines the ink amount when printing clear ink on each pixel based on the target deflection angle characteristics.

[0147] [Processing flow] FIG. 17 is a flowchart showing the flow of processing in this embodiment from when the image processing device 1 generates print data to when it outputs the print data.

[0148] The clear ink used in the recording device 111 is either the first clear ink or the second clear ink. In this embodiment, the description will be given assuming that the first clear ink (CL1) which has smaller isotropy than the other inks is used.

[0149] In S1701, the image acquisition unit 1601 acquires an image to be recorded on a recording medium, that is, image data to be recorded, from an external device such as the HDD 113. The image data acquired in S1701 is, for example, data of an RGB image, and will be described as having no P plate.

[0150] In S1702, the color ink amount / fluorescent ink amount determination unit 1602 determines the ink amount CMYKP(x,y) at the pixel position (x,y). The ink amount CMYKP(x,y) is composed of five signal values, and each signal value is density value data for each color ink of C, M, Y, K, and the fluorescent ink of P. The color ink amount / fluorescent ink amount determination unit 1602 determines the ink amount CMYKP(x,y) using a general method such as using a previously prepared LUT in which RGB and CMYKP are associated. When generating print data for a printing device equipped with special color inks, the data may be converted from RGB image data to the amount of each ink including the special color ink. By expressing colors with a group of inks including the fluorescent ink of P, a wide color gamut including bright pink can be expressed.

[0151] In S1703, the target deflection angle characteristic determination unit 1603 calculates a ratio R T Determine the target ratio R T For example, if the isotropy of the clear ink used in the recording device 111 is smaller than that of the other inks, the ratio R T can be determined as follows:

[0152] First, for each pixel position (x, y), the ratio R indicating the deviation angle characteristic (the magnitude of isotropy) when printed with the ink amount CMYKP(x, y) determined in S1702 is calculated. CMYKP Determine (x,y).

[0153] FIG. 18(a) shows the ratio R when the ink amount of each of the CMYKP inks is combined and printed with that ink amount. CMYKP 1 is a diagram showing an example of an LUT in which the values ​​of the ink amounts CMYKP(x, y) are associated with each other. Using this LUT, the ratio R CMYKP (x,y) can be determined.

[0154] Columns C, M, Y, K, and P of the LUT in Figure 18(a) hold the ink amount of each ink in a specified grid unit. Column C holds the ink amount of colored ink (C). Column M holds the ink amount of colored ink (M). Column Y holds the ink amount of colored ink (Y). Column K holds the ink amount of colored ink (K). Column P holds the ink amount of fluorescent ink (P).

[0155] Y 0-45 The columns hold the luminance at an incident angle of 0° and a receiving angle of 45° when printing is performed with the ink amounts held in columns C, M, Y, K, and P. 0-75 The columns hold the luminance at an incident angle of 0° and a receiving angle of 75° when printing is performed with the ink amounts held in columns C, M, Y, K, and P. CMYKP The columns are the ratios R CMYKP (R CMYKP =Y 0-75 / Y 0-45 ) is held.

[0156] The values ​​indicating the ink amounts held in the LUT in Fig. 18A are assumed to be print duty conversion values ​​[%]. Therefore, the ink amounts CMYKP(x, y) determined in S1702 are converted into print duty conversion values, and then the LUT in Fig. 18A is referenced to determine the ratio R CMYKP (x, y) is determined. In this embodiment, CMYK and P are not exclusive but may be mixed. For this reason, in the LUT of FIG. 18, even in a row where a value greater than 0 is held in the P column, a value greater than 0 may be held in each column of CMYK.

[0157] The target deflection angle characteristic determination unit 1603 determines the R CMYKP By applying (x, y) to equation (5), the ratio R T Calculate.

[0158] R T =Min(R CMYKP (x,y)) Equation (5) In equation (5), Min is a function that calculates the minimum value. In other words, the ratio R CMYKP The minimum value of (x, y) is the ratio R, which indicates the target deviation characteristic. T In the process described below, a large amount of clear ink is recorded at positions where the amount of ink with a large isotropy is large, so that the deviation angle characteristic approaches the target deviation angle characteristic.

[0159] In S1704, the clear ink amount determination unit 1604 determines the ink amount CL(x, y) of the first clear ink when printing at position (x, y) for all positions within the image.

[0160] First, for the target position (x, y), the ratio R CMYKP_CLDetermine (x, y). In this embodiment, the following explanation will be given assuming the predetermined ink amount to be 100.

[0161] FIG. 18B shows a ratio R when a first clear ink is applied in an ink amount of 100 to an area printed with the ink amount of each of the CMYKP inks. CMYKP_CL Using this LUT, the ratio R of the position (x, y) is calculated from the ink amounts CMYKP(x, y) determined in S1702. CMYKP_CL (x,y) can be determined.

[0162] Columns C, M, Y, K, and P of the LUT in Figure 18(b) hold the ink amount of each ink in a predetermined grid unit. Column C holds the ink amount of colored ink (C). Column M holds the ink amount of colored ink (M). Column Y holds the ink amount of colored ink (Y). Column K holds the ink amount of colored ink (K). Column P holds the ink amount of fluorescent ink (P). Column CL holds a uniform ink amount CL100 of the first clear ink.

[0163] Y 0-45_CL The columns hold the luminance at an incident angle of 0° and a receiving angle of 45° when printing is performed with the ink amounts held in columns C, M, Y, K, P, and CL. 0-75_CL The columns hold the luminance at an incident angle of 0° and a receiving angle of 75° when printing is performed with the ink amounts held in columns C, M, Y, K, P, and CL. CMYKP_CL The columns are the ratios R CMYKP_CL (R CMYKP_CL =Y 0-75_CL / Y 0-45_CL ) is held.

[0164] Then, the clear ink amount determination unit 1604 calculates the ink amount CL(x, y) of the first clear ink when recording at the position (x, y) using the formula (6). CMYKP (x,y) is the amount of each ink in CMYKP and the ratio R CMYKPThe LUT is determined by referring to the LUT in FIG.

[0165] CL(x,y)=(100 / (R CMYKP_CL (x,y)-R CMYKP (x,y)))·(R T -R CMYKP (x,y)) Equation (6) Equation (6) is a commonly used linear interpolation formula. When the deflection angle characteristics change linearly according to the amount of clear ink, the ratio R that indicates the target deflection angle characteristics can be calculated using equation (6). T It is possible to determine the ink amount CL(x, y) of the clear ink such that

[0166] S1705 is the same process as S1208, and the print data generation unit 1107 generates print data for each ink. That is, binarization is performed on the determined ink amount CMYKP(x,y) data and the clear ink ink amount CL(x,y) data, and print data for each ink is generated. The output unit 1108 outputs the print data to the printing device 111. The printing device 111 prints an image based on the received print data.

[0167] It should be noted that the flowchart in Fig. 17 may include a step of determining whether or not clear ink is to be used in recording an image, like S1205 in Fig. 12. Then, if it is determined that clear ink is to be used, S1704 may be performed.

[0168] As described above, according to this embodiment, it is possible to determine the amount of clear ink for each pixel so as to approach the target deflection angle characteristics based on the deflection angle characteristics corresponding to the ink amounts of color ink and fluorescent ink for each pixel. Furthermore, even if the deflection angle characteristics of the paper white and each ink are significantly different, it is possible to obtain the effect of making the deflection angle characteristics uniform across the entire print. This makes it possible to suppress image defects such as tone inversion and color balance loss when the observation angle is changed across the entire print.

[0169] <Other embodiments> The image processing functional units shown in FIGS. 11, 13, and 16 may be realized in the recording device 111.

[0170] In the above embodiment, the fluorescent ink is described as being more isotropic than the colored ink. Even if the colored ink is more isotropic than the fluorescent ink, it goes without saying that the same effect can be obtained by reversing the relationship between the colored ink and the fluorescent ink in the above embodiment.

[0171] In the above-described embodiment, the magnitude of isotropy is expressed as the ratio of luminance at two different observation angles, but other feature quantities indicating brightness, such as lightness or density, may be used instead of luminance. The magnitude of isotropy may also be expressed as the difference between feature quantities at different observation angles. Furthermore, in order to take into account responsiveness and linearity with respect to the amount of clear ink, correction such as gamma conversion processing may be performed on the numerical values.

[0172] The present disclosure can also be realized by a process in which a program capable of executing one or more functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0173] The disclosure of the above-described embodiment includes the following configurations.

[0174] (Configuration 1) 1. An image processing device that generates data to be output to a recording device that records an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, comprising: a generating means for generating recording data for causing the recording device to deposit ink based on image data; an output unit for outputting the recording data; The generating means generates the recording data for causing the recording device to apply the clear ink to the recording medium so as to reduce a difference in degree of change in brightness depending on an observation angle between an area to which the fluorescent ink is applied and an area to which the colored ink is applied. 13. An image processing device comprising:

[0175] (Configuration 2) the clear ink is composed of a first clear ink and a second clear ink that is more isotropic than the first clear ink, The generating means includes: The print data is generated so that the first clear ink is applied to the area where the fluorescent ink is applied, and the second clear ink is applied to the area where the colored ink is applied. 2. The image processing device according to claim 1,

[0176] (Configuration 3) The second clear ink is a clear ink having greater isotropy than the fluorescent ink and the colored ink. 3. The image processing device according to configuration 2.

[0177] (Configuration 4) The first clear ink is a clear ink having a lower isotropy than the fluorescent ink and the color ink. 4. The image processing device according to configuration 2 or 3.

[0178] (Configuration 5) the clear ink is a clear ink having less isotropy than the fluorescent ink and the colored inks, The generating means includes: The print data is generated so that a larger amount of the clear ink is applied to an area to which the fluorescent ink has been applied than to an area to which the fluorescent ink has not been applied. 2. The image processing device according to claim 1,

[0179] (Configuration 6) the clear ink is a clear ink having greater isotropy than the fluorescent ink and the colored inks, The generating means includes: The print data is generated so that a larger amount of the clear ink is applied to an area to which the color ink is applied than to an area to which the color ink is not applied. 2. The image processing device according to claim 1,

[0180] (Configuration 7) The generating means includes: comparing a first value, which is a difference in magnitude of isotropy between the fluorescent ink and the clear ink, with a second value, which is a difference in magnitude of isotropy between the colored ink and the clear ink; if the first value is greater than the second value, generating the recording data so that a larger amount of the clear ink is applied to the area to which the fluorescent ink has been applied than to an area to which the fluorescent ink has not been applied; if the second value is greater than the first value, the print data is generated so that a larger amount of the clear ink is applied to the area to which the color ink is applied than to an area to which the color ink is not applied. 2. The image processing device according to claim 1,

[0181] (Configuration 8) the image data is composed of first image data whose pixel values ​​correspond to the color inks, and second image data whose pixel values ​​correspond to the fluorescent inks, The pixel values ​​of the pixels are maintained so that the fluorescent ink is not applied to the area where the color ink is applied. 8. The image processing device according to any one of configurations 1 to 7,

[0182] (Configuration 9) a first ink amount determination means for determining an ink amount of the color ink and the fluorescent ink for each pixel based on data of the image; a second ink amount determination means for determining an ink amount of the clear ink for each pixel based on the ink amounts of the color inks and the fluorescent ink, The generating means generates the recording data based on the determined ink amounts of each ink. 2. The image processing device according to claim 1,

[0183] (Configuration 10) The method further includes a determination means for determining a target magnitude of isotropy, The second ink amount determination means determines the ink amount of the clear ink so that the magnitude of isotropy of the image becomes the target magnitude of isotropy. 10. The image processing device according to configuration 9.

[0184] (Configuration 11) The second ink amount determination means determining, for each pixel, a first value that indicates the degree of isotropy when the determined ink amounts of the color ink and the fluorescent ink are applied; determining, for each pixel, a second value that indicates the magnitude of isotropy when a predetermined ink amount of the clear ink and the determined ink amounts of the color ink and the fluorescent ink are applied; The amount of the clear ink is determined based on the first value and the second value for each pixel and the value indicating the magnitude of the target isotropy. 11. The image processing device according to configuration 10.

[0185] (Configuration 12) the recording device is configured to be able to set either a first mode in which recording is performed using the clear ink or a second mode in which recording is performed without using the clear ink; The generating means includes: When the first mode is set in the recording device, the recording data is generated to cause the recording device to deposit the clear ink onto a recording medium. 12. The image processing device according to any one of configurations 1 to 11,

[0186] (Configuration 13) The magnitude of isotropy is a value indicating the magnitude of a second feature quantity, which indicates the brightness when observed at a second observation angle that is larger than the first observation angle, relative to a first feature quantity, which indicates the brightness when observed at a first observation angle. 5. The image processing device according to any one of configurations 2 to 4.

[0187] (Configuration 14) the feature indicating brightness is any one of luminance, brightness, and density, The value indicating the magnitude of the second feature amount relative to the first feature amount is either a ratio of the second feature amount to the first feature amount or a difference between the first feature amount and the second feature amount. 14. The image processing device according to claim 13,

[0188] (Configuration 15) The color ink is a subtractive ink and is less isotropic than the fluorescent ink. 15. The image processing device according to any one of configurations 1 to 14.

[0189] (Configuration 16) A recording device that records an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, The clear ink is applied to the recording medium so that a difference in the degree of change in brightness depending on the observation angle between an area to which the fluorescent ink is applied and an area to which the color ink is applied is reduced in a printed matter obtained by recording an image on the recording medium. A recording device comprising:

[0190] (Configuration 17) 1. An image processing method for generating data to be output to a recording device that records an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, comprising: a generating step of generating recording data for causing the recording device to apply ink based on image data; and an output step of outputting the recording data, In the generating step, the recording data is generated to cause the recording device to apply the clear ink to the recording medium so that a difference in degree of change in brightness due to an observation angle between an area to which the fluorescent ink is applied and an area to which the colored ink is applied is reduced. 13. An image processing method comprising:

[0191] (Configuration 18) A recording method for recording an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, the method comprising the steps of: The clear ink is applied to the recording medium so that a difference in the degree of change in brightness depending on the observation angle between an area to which the fluorescent ink is applied and an area to which the color ink is applied is reduced in a printed matter obtained by recording an image on the recording medium. A recording method comprising:

[0192] (Configuration 19) A program for causing a computer to execute each of the means of the image processing device according to any one of configurations 1 to 15. [Explanation of symbols]

[0193] 1 Image processing device 111 Recording devices

Claims

1. 1. An image processing device that generates data to be output to a recording device that records an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, comprising: a generating means for generating recording data for causing the recording device to deposit ink based on image data; an output unit for outputting the recording data; The generating means generates the recording data for causing the recording device to apply the clear ink to the recording medium so as to reduce a difference in degree of change in brightness depending on an observation angle between an area to which the fluorescent ink is applied and an area to which the colored ink is applied.

13. An image processing device comprising:

2. the clear ink is composed of a first clear ink and a second clear ink having greater isotropy than the first clear ink, The generating means includes: The print data is generated so that the first clear ink is applied to the area where the fluorescent ink is applied, and the second clear ink is applied to the area where the colored ink is applied.

2. The image processing device according to claim 1,

3. The second clear ink is a clear ink having greater isotropy than the fluorescent ink and the colored ink.

3. The image processing device according to claim 2.

4. The first clear ink is a clear ink having a lower isotropy than the fluorescent ink and the color ink.

3. The image processing device according to claim 2.

5. the clear ink is a clear ink having less isotropy than the fluorescent ink and the colored inks, The generating means includes: The print data is generated so that a larger amount of the clear ink is applied to an area to which the fluorescent ink has been applied than to an area to which the fluorescent ink has not been applied.

2. The image processing device according to claim 1,

6. the clear ink is a clear ink having greater isotropy than the fluorescent ink and the colored inks, The generating means includes: The print data is generated so that a larger amount of the clear ink is applied to an area to which the color ink is applied than to an area to which the color ink is not applied.

2. The image processing device according to claim 1,

7. The generating means includes: comparing a first value, which is a difference in magnitude of isotropy between the fluorescent ink and the clear ink, with a second value, which is a difference in magnitude of isotropy between the colored ink and the clear ink; if the first value is greater than the second value, generating the recording data so that a larger amount of the clear ink is applied to the area to which the fluorescent ink has been applied than to an area to which the fluorescent ink has not been applied; if the second value is greater than the first value, the print data is generated so that a larger amount of the clear ink is applied to the area to which the color ink has been applied than to an area to which the color ink has not been applied.

2. The image processing device according to claim 1,

8. The image data is composed of first image data in which pixel values ​​correspond to the color inks, and second image data in which pixel values ​​correspond to the fluorescent inks, and the pixel values ​​of each pixel are maintained so that the fluorescent ink is not applied to the areas to which the color inks are applied.

2. The image processing device according to claim 1,

9. a first ink amount determination means for determining an ink amount of the color ink and the fluorescent ink for each pixel based on data of the image; a second ink amount determination unit that determines an ink amount of the clear ink for each pixel based on the ink amounts of the color inks and the fluorescent ink, The generating means generates the recording data based on the determined ink amounts of each ink.

2. The image processing device according to claim 1,

10. The method further includes a determination means for determining a target magnitude of isotropy, The second ink amount determination means determines the ink amount of the clear ink so that the magnitude of isotropy of the image becomes the target magnitude of isotropy.

10. The image processing device according to claim 9,

11. The second ink amount determination means determining, for each pixel, a first value that indicates the degree of isotropy when the determined ink amounts of the color ink and the fluorescent ink are applied; determining, for each pixel, a second value that indicates the magnitude of isotropy when a predetermined ink amount of the clear ink and the determined ink amounts of the color ink and the fluorescent ink are applied; The amount of the clear ink is determined based on the first value and the second value for each pixel and the value indicating the magnitude of the target isotropy. The image processing device according to claim 10 .

12. the recording device is configured to be able to set either a first mode in which recording is performed using the clear ink or a second mode in which recording is performed without using the clear ink, The generating means includes: When the first mode is set in the recording device, the recording data is generated to cause the recording device to deposit the clear ink onto a recording medium.

2. The image processing device according to claim 1,

13. The magnitude of isotropy is a value indicating the magnitude of a second feature quantity, which indicates the brightness when observed at a second observation angle that is larger than the first observation angle, relative to a first feature quantity, which indicates the brightness when observed at a first observation angle.

3. The image processing device according to claim 2.

14. the feature indicating brightness is any one of luminance, brightness, and density, The value indicating the magnitude of the second feature amount relative to the first feature amount is either a ratio of the second feature amount to the first feature amount or a difference between the first feature amount and the second feature amount. The image processing device according to claim 13 .

15. The color ink is a subtractive ink and is less isotropic than the fluorescent ink.

2. The image processing device according to claim 1,

16. A recording device that records an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, The clear ink is applied to the recording medium so that a difference in the degree of change in brightness depending on the observation angle between an area to which the fluorescent ink is applied and an area to which the color ink is applied is reduced in a printed matter obtained by recording an image on the recording medium. A recording apparatus comprising:

17. 1. An image processing method for generating data to be output to a recording device that records an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, comprising: a generating step of generating recording data for causing the recording device to apply ink based on image data; and an output step of outputting the recording data, In the generating step, the recording data is generated to cause the recording device to apply the clear ink to the recording medium so that a difference in degree of change in brightness due to an observation angle between an area to which the fluorescent ink is applied and an area to which the colored ink is applied is reduced.

13. An image processing method comprising:

18. A recording method for recording an image on a recording medium using a fluorescent ink containing a fluorescent component, a color ink not containing a fluorescent component, and a clear ink not containing a color material, the method comprising the steps of: The clear ink is applied to the recording medium so that a difference in the degree of change in brightness depending on the observation angle between an area to which the fluorescent ink is applied and an area to which the color ink is applied is reduced in a printed matter obtained by recording an image on the recording medium. A recording method comprising:

19. A program for causing a computer to execute each of the means of the image processing apparatus according to any one of claims 1 to 15.

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