Image recording device, image processing method and program

Abstract

To solve the problem that when color ink is applied before fusion of metallic ink is completed, an ill effect on an image that the metallic ink shows brown color tone may occur, at a boundary between the metallic ink and the color ink.SOLUTION: A time for fusion of metallic ink is secured to suppress an ill effect on an image from occurring at a boundary part, by changing a time difference between scanning in which the metallic ink is applied and scanning in which color ink is applied so that the time difference becomes larger.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] In recent years, image recording devices have become known that record images on recording media using metallic ink containing metal particles. By using such metallic ink, it is possible to impart a metallic luster to the recorded matter. For example, as described in Patent Document 1, a recording method using metallic ink containing silver particles is known. Hereinafter, recording of metallic images will be referred to as metallic recording.

[0003] Furthermore, by using colored inks of cyan, magenta, yellow, and black, it is possible to record colored images and color metallic images. A color metallic image is a colored image with a metallic luster that is recorded by depositing colored inks on top of metallic ink. Hereinafter, recording of a color metallic image will be referred to as color metallic recording. Patent Document 2 describes a method for recording an image using metallic ink. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-55463 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-183677 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a problem that the metallic luster decreases at the boundary between the recording area to which metallic ink is applied and the recording area to which colored ink is applied, resulting in a decrease in image quality. Although Patent Document 2 discloses a method for controlling the application order of metallic ink and colored ink onto a recording medium, no disclosure is made regarding a solution to such a problem.

[0006] The present invention has been made to reduce the above-described problems, and an object thereof is to provide an image recording apparatus capable of suppressing a decrease in image quality at the boundary between an area to which metallic ink is applied and an area to which colored ink is applied.

Means for Solving the Problems

[0007] The present invention includes a recording means in which a plurality of recording elements for applying metallic ink containing metal particles are arranged in a first direction, and a plurality of recording elements for applying colored ink containing a coloring material are arranged in the first direction, scanning means for relatively scanning the recording means in a second direction intersecting the first direction, generation means for generating dot data indicating ink application or non-application to each pixel for each of N (N: an integer of 2 or more) scans of the recording means and a recording medium, and control means for controlling the recording means and the scanning means so as to complete the recording of an image for a unit area by the N scans based on the dot data generated by the generation means. The generation means detects edge pixels that are pixels where metallic ink is not applied and are adjacent to pixels where metallic ink is applied based on input data, generates dot data indicating ink application or non-application to each pixel for each of the N scans based on the input data, changes data indicating application of colored ink to the edge pixels in the dot data of the L (L: an integer of 2 or more, and L < N) -th scan generated, to data in the dot data of the M (M: an integer of 3 or more, and L < M ≦ N) -th scan, and generates data indicating application of metallic ink to pixels adjacent to the edge pixels in the dot data of scans before the M -th scan.

Effects of the Invention

[0008] According to the present invention, it is possible to suppress deterioration in image quality at the boundary between the metallic image area and the color image area. [Brief explanation of the drawings]

[0009] [Figure 1] Diagram showing the configuration of the image recording device [Figure 2] A diagram showing the recording section of an image recording device. [Figure 3] Diagram showing the recording head [Figure 4] Diagram showing silver particle fusion in Me ink [Figure 5] Diagram showing silver particle distribution in Me ink dots [Figure 6] A diagram showing when an Me ink dot and a colored ink dot land adjacent to each other. [Figure 7] Flowchart showing the process of the first embodiment [Figure 8] A diagram showing an example of pixel arrangement and colored area attributes for Me ink [Figure 9] A diagram showing an example of an edge extraction filter [Figure 10] An example of colored region boundary attributes [Figure 11] A diagram showing an example of quantized data [Figure 12] Diagram for explaining nozzles and scan numbers [Figure 13] A diagram showing an example of a thinning mask [Figure 14] FIG. 10 is a diagram showing an example of changing a thinning mask according to the first embodiment; [Figure 15] FIG. 10 is a diagram showing the effect of changing the landing order of colored ink dots in the first embodiment. [Figure 16] Graph showing the relationship between the amount of Me ink and the fusion time in the first embodiment. [Figure 17] Flowchart of the second embodiment [Figure 18] Flowchart of the third embodiment [Figure 19] FIG. 10 is a diagram showing an example of changing a thinning mask according to the third embodiment. [Figure 20] Expansion mask and correspondence table between quantization value and expansion mask value [Figure 21] A diagram showing a probability mask DETAILED DESCRIPTION OF THE INVENTION

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

[0011] <Entire Recording System> FIG. 1 is a block diagram illustrating the configuration of a recording system usable in this embodiment. The image processing device 101 comprises a host PC, tablet PC, or the like, and a CPU 102 executes various processes using a RAM 103 as a work area in accordance with a program stored in a HDD 104. For example, the CPU 102 generates image data recordable by the recording device 108 in accordance with commands received from a user via a keyboard / mouse I / F 106 or a touch panel (not shown) or a program stored in the HDD 104, and transfers this data to the printer 108. The CPU 102 also performs predetermined processing on image data received from the recording device 108 via a data transfer I / F 107 in accordance with a program stored in the HDD, and displays the results and various information on a display (not shown) via a display I / F 105. The image processing device 101 can also perform similar processing on the target printer 116.

[0012] Meanwhile, in the recording device 108, the CPU 111 executes various processes using the RAM 112 as a work area in accordance with programs stored in the ROM 113. The recording device 108 also includes an image processing accelerator 109 for performing high-speed image processing. The image processing accelerator 109 is hardware capable of executing image processing faster than the CPU 111. The image processing accelerator 109 is activated when the CPU 111 writes parameters and data required for image processing to a predetermined address in the RAM 112, and after reading the parameters and data, executes predetermined image processing on the data. However, the image processing accelerator 109 is not an essential element, and equivalent processing can be executed by the CPU 111. The parameters may be stored in the ROM 113, or may be stored in storage (not shown) such as a flash memory or a HDD.

[0013] Here, we will explain the predetermined image processing performed by the CPU 111 or the image processing accelerator 109. This image processing is processing up to and including the conversion of input data into data indicating the ink dot formation positions for each scan.

[0014] First, the CPU 111 or the image processing accelerator 109 performs color conversion and quantization on the input data. The input data is color-converted to ink densities used in the printing device through color conversion. For example, the input data includes image data representing an image and metallic data for metallic printing. If the image data indicates color space coordinates such as sRGB, which are the representation colors of the monitor, the color conversion process converts the sRGB color coordinate (R, G, B) data into colored ink data (CMYK) for the printing device. On the other hand, the metallic data is converted into Me ink color data. If both color coordinates (R, G, B) and metallic data are included, the data is converted into both colored ink data (CMYK) and Me ink data. The color conversion process is realized using known techniques such as matrix calculation processing, processing using a three-dimensional LUT, or a four-dimensional LUT. The printing device 108 of this embodiment is a printing device that prints images using black (K), cyan (C), magenta (M), yellow (Y), and metallic (Me) inks, so the image data and metallic data, which are RGB signals, are color-converted into image data consisting of 8-bit color signals for C, M, Y, K, and Me. The color signals for each color correspond to the amount of each ink applied.

[0015] Although the five ink colors K, C, M, Y, and Me have been given as an example of the ink colors provided in the recording device, other inks such as light cyan (Lc), light magenta (Lm), and gray (Gy) inks with lower densities may also be used to improve image quality. In this case, ink signals corresponding to these inks are also generated.

[0016] In this embodiment, inks containing coloring materials are described as colored inks, as opposed to metallic inks containing metal particles. Therefore, light inks such as light cyan (Lc) and light magenta (Lm) and achromatic inks such as black (K) and gray (Gy) are also treated as colored inks.

[0017] After the color conversion process, the ink data for each ink color is subjected to a quantization process. The quantization process reduces the number of gradation levels in the ink data. In this embodiment, a dither matrix is used, which arranges threshold values for comparison with the ink data value for each pixel. This quantization process ultimately results in dot data that indicates whether or not an ink dot is to be applied to each pixel. The dot data in this embodiment is binary data, with "1" indicating that ink is to be applied, and "1" indicating that ink is not to be applied.

[0018] After the above image processing, the print data is transferred to the print head 115 by the print head controller 114. At the same time, the CPU 111 operates the carriage motor that operates the print head 115, and also operates the transport motor that transports the print medium. At the same time that the print head scans over the print medium, ink droplets ejected from the print head 115 based on the dot data land, forming an image on the print medium.

[0019] In this embodiment, so-called multi-pass printing is performed, in which image printing is completed by scanning the print head 115 multiple times over a unit area. Then, before performing multi-pass printing, a scan order determination process is performed on the dot data after quantization processing. The scan order determination process is a process that generates data corresponding to each scan in multi-pass printing by thinning out the dot data after quantization processing using a mask pattern or the like. Here, the image processing accelerator 109 is used to speed up the processing.

[0020] The image processing device 101 is connected to the recording device 108 via a communication line 118. In this embodiment, the communication line 118 is described as Ethernet (registered trademark), but it may also be a connection using a USB hub, a wireless communication network using a wireless access point, or a Wi-Fi Direct communication function.

[0021] <Regarding the recording section of the recording device> FIG. 2 is a diagram illustrating the print head 115 constituting the printing unit 108 in this embodiment. The print head 115 is mounted on a carriage 116. It includes a nozzle array for ejecting four colored inks (hereinafter also referred to as color inks): cyan (C), magenta (M), yellow (Y), and black (K), and a nozzle array for ejecting metallic (Me) ink. The nozzle arrays 115k, 115c, 115m, and 115y for ejecting colored inks and the nozzle array 115Me for ejecting metallic ink each include a plurality of printing elements for ejecting ink, and ink is ejected from each nozzle by driving each printing element. The print head 115 also includes an optical sensor 118.

[0022] A carriage 116 carrying a recording head 115 can move back and forth in the X direction (the so-called main scanning direction) in the figure by the driving force of a carriage motor transmitted via a belt 117. While the carriage 116 moves in the X direction relative to the recording medium, ink is ejected from each nozzle in the direction of gravity (the -z direction in the figure) based on dot data, thereby recording an image for one main scanning pass on the recording medium placed on a platen 119. When one main scanning pass is completed, the recording medium is transported a predetermined distance in the transport direction, which is the -y direction in the figure. By alternately repeating such main scanning and transport operations, an image is gradually formed on the recording medium.

[0023] The optical sensor 118 performs a detection operation while moving together with the carriage 116 to determine whether a recording medium is present on the platen 119 .

[0024] <Recording head> FIG. 3 shows the arrangement of nozzle arrays when the print head 115 is viewed from the top of the device (in the -z direction). The print head 115 has five nozzle arrays: a nozzle array 115c corresponding to cyan ink, a nozzle array 115m corresponding to magenta ink, a nozzle array 115y corresponding to yellow ink, a nozzle array 115k corresponding to black ink, and a nozzle array 115Me corresponding to metallic ink. The nozzle arrays are arranged at different positions in the X direction. Cyan ink is ejected from the nozzles of the nozzle array 115c. Magenta ink is ejected from the nozzles of the nozzle array 115m. Yellow ink is ejected from the nozzles of the nozzle array 115y. Black ink is ejected from the nozzles of the nozzle array 115k. Metallic ink is ejected from the nozzle array 115Me. Each nozzle array has a plurality of nozzles arranged at a predetermined pitch along the Y direction for ejecting ink droplets. Each nozzle has an electrothermal conversion element serving as a printing element, which converts electrical energy into thermal energy.

[0025] <Silver nano ink> Next, each component constituting the metallic ink containing silver particles used in this embodiment will be described.

[0026] <Silver particles> The silver particles used in this embodiment are particles containing silver as the main component, and the silver purity in the silver particles may be 50% by mass or more. For example, the silver particles may contain other metals, oxygen, sulfur, carbon, etc. as secondary components, or may be alloys.

[0027] The method for producing the silver particles is not particularly limited. However, taking into consideration particle size control and dispersion stability of the silver particles, silver particles produced by various synthesis methods utilizing a reduction reaction from a water-soluble silver salt are preferred.

[0028] The average particle size of the silver particles used in this embodiment is preferably 1 nm or more and 200 nm or less, and more preferably 10 nm or more and 100 nm or less, from the viewpoints of the storage stability of the ink and the glossiness of the image formed with the silver particles.

[0029] Specific methods for measuring the average particle size include FPAR-1000 (manufactured by Otsuka Electronics, cumulant analysis) and Nanotrac UPA150EX (manufactured by Nikkiso Co., Ltd., using an integrated value of 50% of the volume average particle size), which utilize the scattering of laser light.

[0030] In this embodiment, the content (mass %) of silver particles in the ink is preferably 2.0% by mass or more and 15.0% by mass or less, based on the total mass of the ink. If the content is less than 2.0% by mass, the metallic gloss of the image may decrease. If the content is more than 15.0% by mass, ink overflow may occur, which may result in print distortion.

[0031] <Dispersant> The dispersion method of the silver particles is not particularly limited. For example, silver particles dispersed with a surfactant, resin-dispersed silver particles dispersed with a dispersion resin, etc. can be used. Of course, metal particles dispersed by different methods can also be used in combination.

[0032] The surfactant may be anionic, nonionic, cationic or amphoteric surfactant. Specifically, the following surfactants may be used:

[0033] Examples of anionic surfactants include fatty acid salts, alkyl sulfate ester salts, alkyl aryl sulfonates, alkyl diaryl ether disulfonates, dialkyl sulfosuccinates, alkyl phosphates, Examples include naphthalenesulfonic acid formalin condensates, polyoxyethylene alkyl phosphate ester salts, and glycerol borate fatty acid esters.

[0034] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene oxypropylene block copolymers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, Examples of the surfactant include polyoxyethylene alkylamine, fluorine-based surfactants, and silicon-based surfactants. Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, and alkylimidazolium salts. Examples of the amphoteric surfactant include alkylamine oxide and phosphatidylcholine.

[0035] Any resin that is water-soluble or water-dispersible can be used as the dispersing resin, but among these, those having a weight average molecular weight of 1,000 or more and 100,000 or less, and more preferably 3,000 or more and 50,000 or less, are particularly preferred.

[0036] Specific examples of dispersing resins that can be used include: polymers containing styrene, vinylnaphthalene, aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids, acrylic acid, maleic acid, itaconic acid, fumaric acid, vinyl acetate, vinylpyrrolidone, acrylamide, or derivatives thereof as monomers. It is preferable that one or more of the monomers constituting the polymer are hydrophilic monomers, and block copolymers, random copolymers, graft copolymers, or salts thereof may be used. Alternatively, natural resins such as rosin, shellac, and starch may also be used.

[0037] In this embodiment, it is preferable that the aqueous ink contains a dispersant for dispersing the silver particles, and that the content (mass %) of the dispersant is 0.02 to 3.00 times the content (mass %) of the silver particles in terms of mass ratio.

[0038] If the mass ratio is less than 0.02 times, the dispersion of the silver particles becomes unstable, and the proportion of silver particles adhering to the heating part of the head increases, which makes abnormal foaming more likely and may result in print distortion due to ink overflow. Also, if the mass ratio is more than 3.00 times, the dispersant may inhibit the fusion of silver particles during image formation, which may reduce the metallic gloss of the image.

[0039] <Surfactant> The silver particle-containing ink used in this embodiment preferably contains a surfactant in order to obtain better-balanced ejection stability. The surfactant may be any of the above-mentioned anionic, nonionic, cationic, and amphoteric surfactants.

[0040] Among these, it is preferable to contain a nonionic surfactant. Among nonionic surfactants, polyoxyethylene alkyl ethers and ethylene oxide adducts of acetylene glycol are particularly preferable. The HLB value (Hydrophile-Lipophile Balance) of these nonionic surfactants is 10 or more. The content of the surfactant used in combination in this manner is preferably 0.1% by mass or more in the ink. It is also preferably 5.0% by mass or less, more preferably 4.0% by mass or less, and even more preferably 3.0% by mass or less.

[0041] <Aqueous medium> The silver particle-containing 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 10% to 50% by mass, more preferably 20% to 50% by mass, based on the total mass of the ink. The content (mass %) of water in the ink is preferably 50% to 88% by mass, based on the total mass of the ink.

[0042] Specific examples of water-soluble organic solvents that can be used include: 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; and 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 having 2 to 6 carbon atoms, 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. Glycerin. Lower alkyl ethers of polyhydric alcohols, such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether. It is preferable to use deionized water (ion-exchanged water).

[0043] <Recording Media> The recording medium of this embodiment has a substrate and at least one ink-receiving layer, and is preferably an inkjet recording medium used in an inkjet image recording method.

[0044] <Mechanism behind the brown appearance of areas printed with metallic ink> Here, we will explain metallic ink. The melting point of metal particles depends on the type of material and the size of the particles, with the smaller the particle size, the lower the melting point. The small silver particles contained in such metallic ink, which are several to several hundred nanometers in diameter, lose their dispersion state as the moisture content decreases after landing on the recording surface, and fuse with nearby silver particles to form a fused silver film. By forming this fused silver film on the recording medium, it is possible to record a metallic image with a metallic luster.

[0045] The metallic ink used in this embodiment is a brownish liquid containing silver particles as metal particles. This color is due to the absorption of specific wavelengths of light caused by a phenomenon called surface plasmon resonance, in which the vibrations of free electrons (plasmons) inside a metal exposed to the electric field of light resonate with the vibrations of light. The absorption wavelength of this surface plasmon resonance varies depending on the shape and size of the particles, but the silver particles used in this embodiment have a peak in their extinction spectrum on the low wavelength side of the visible light range, resulting in a brownish liquid.

[0046] Metallic ink containing silver particles exhibits a brownish tint in liquid form due to plasmon resonance. When this metallic ink is used for inkjet recording, if a metallic recording area and a colored recording area are adjacent to each other, the density of the silver particles in the metallic ink decreases due to the solvent in the colored ink, resulting in insufficient fusion of the silver particles, resulting in a brownish tint. This insufficient fusion of the silver particles creates a problem in that the boundary between the metallic recording area containing silver particles and the colored recording area appears brownish.

[0047] Figure 4 is an explanatory diagram of the mechanism by which dots made with Me ink appear brownish. Figure 4(a) is a schematic diagram showing the cross section of Me ink at the moment it hits the recording medium. The cross section of Me ink becomes dome-shaped due to the surface tension of the ink. Furthermore, silver particles are evenly dispersed inside this dome-shaped ink.

[0048] Figure 4(b) shows the state in which the aqueous medium of the Me ink has penetrated the media and the silver particles have been trapped on the media surface. Because the ink is dome-shaped before the aqueous medium penetrates, there are more silver particles per unit area on the media at the center of the dot and they become smaller as you approach the periphery of the dot. When the aqueous medium penetrates the media, the silver particles that were floating in the aqueous medium land on the surface of the media directly below, so the density of silver particles on the media surface is higher at the center of the dot and lower as you approach the periphery of the dot.

[0049] Figure 4(c) shows the state of silver particles trapped on the media surface after fusing. Because silver particle fusion occurs due to contact between particles, fusion is more likely in areas with higher silver particle density. Therefore, the density of silver particles is lower near the periphery of the dot, and there are more isolated silver particles, so the probability of fusion is lower than in the center of the dot.

[0050] FIG. 5 is a schematic diagram showing the state in which one dot of Me ink has been applied. FIG. 5(a) shows the density distribution of silver particles after penetration of an aqueous solvent, and FIG. 5(b) shows the state in which contacting silver particles have fused to form a silver film. In areas of low silver particle density, there are silver particles that are not in contact with each other and are not fused. The Me ink used in this embodiment exhibits a brownish tint due to the aforementioned plasmon resonance when the silver is in particulate form and not fused. Therefore, in areas of low silver particle density where fusion is difficult, the brownish tint due to plasmon resonance remains. This is the mechanism by which Me dots exhibit a brownish tint.

[0051] FIG. 6 is a diagram illustrating the state of the Me ink at the boundary with the colored ink. This diagram shows the state in which a dot of Me ink 601 lands on the recording medium, followed by a colored ink 602. At this time, the Me ink 601 and the colored ink 602 are adjacent to each other, and the solvent of the colored ink 602 mixes with the Me ink 601. As a result, the density of the silver particles further decreases at the boundary between the Me ink 601 and the colored ink 602, causing the Me dot to take on a brownish tint. This can occur with any of the colored inks: C, M, Y, and K. The brownish tint is particularly pronounced with the Y ink because the color density of the colorant is low.

[0052] To address this issue, one method is to stop the scanning of the carriage 116 after applying the metallic ink in order to allow time for the ink to fuse before applying the colored ink. However, if the method of stopping the carriage after each printing scan to wait for the ink to fuse takes 8 to 10 seconds, the total printing time for one sheet of printing medium will be long.

[0053] <Process flow 1> The processing flow in this embodiment will be described with reference to Figure 7. In step S701, the recording device 108 receives data transmitted by the image processing device 101. As described above, the input print data includes RGB data representing color recording and metallic data representing metallic recording.

[0054] In step S702, data indicating the ink amount of Me ink is generated from the metallic data received in step S701. Here, the data is generated using a known method such as a one-dimensional LUT that represents the relationship between the metallic data and the Me ink amount. Note that the image processing device 101 may also convert the metallic data into data on the Me ink amount. In this case, step S702 is skipped.

[0055] 8(a) shows the generated Me ink amount data, which is a value indicating the ink amount for each pixel in order in the X direction, with the upper left corner as the origin. This Me ink amount data is then saved in RAM 112.

[0056] In step S703, colored region data is generated from the Me ink amount data generated in step S702. In this embodiment, a region where the Me ink amount is 0, i.e., a region where Me ink is not applied, is defined as a colored region, and information on whether or not it is a colored region is stored as an attribute value. For the attribute value, "1" indicates a colored region, and "0" indicates a non-colored region.

[0057] FIG. 8(b) shows colored area data generated based on the Me ink amount data in FIG. 8(a), which is stored in RAM 112 as attribute values indicating the colored area, pixel by pixel in order in the X direction with the upper left corner as the origin.

[0058] In step S704, boundary pixels are detected from the colored region data generated in step S703. In this embodiment, an edge extraction filter method is used. FIGS. 9A and 9B show an example of an edge extraction filter, and a known filter such as a Sobel filter may be used. After filter processing, pixels that are not "0" are determined to be edges and their attribute values are set to "1." The edge extraction filter extracts both edges with attribute values of "1" and edges with attribute values of "0." In this embodiment, the purpose is to extract edges with attribute values of "1," i.e., edges of influential regions. Therefore, even if a pixel is determined to be an edge by filter processing, if the attribute value of the pixel of interest is "0," the pixel value of the edge extraction result is also changed to "0."

[0059] FIG. 10 shows the detection results of edge pixels on the colored area side detected in step S704. The edge pixels detected here are pixels to which Me ink is not applied and are adjacent to pixels to which Me ink is applied. The edge pixels detected with the configuration of this embodiment also include white pixels to which neither Me ink nor colored ink is applied. The results are stored in RAM 112 as attribute values of the boundary (edge) of the colored area for each pixel, in order in the X direction with the upper left corner as the origin. Note that the number of processing bits can be reduced by performing a filter process on the attribute values. As a result, the amount of data transfer can be reduced, which further improves processing speed even when processing with an image processing accelerator.

[0060] In step S705, the input data received in step S701 is subjected to predetermined image processing by the CPU 111 or the image processing accelerator 109 described above.

[0061] FIG. 11 shows an example of the processing results of step S705. In the figure, pixels marked "1" indicate pixels to which ink dots are applied, and pixels marked "0" indicate pixels to which ink dots are not applied. In the image data of this example, C ink is applied to the same pixel position as Me ink, and Y ink is applied to pixel positions exclusive of Me ink. In this case, since Y ink is applied to pixels adjacent to Me ink, there is a possibility that the image defect described above, in which Me ink appears brown, may occur at the boundary between the area to which Y ink is applied and the area to which Me ink is applied.

[0062] In steps S706, S707, and S708, the above-described scan order determination process is performed to determine the scan number in which ink dots are applied to each pixel, i.e., the order in which ink dots will land.

[0063] Figure 12 is a diagram showing the correspondence between the nozzle positions of the print head and the scan order in multi-pass printing. Starting from the upstream side in the print medium transport direction (the Y direction in the figure), there is the area of the first scan, followed by the area of the second scan, and finally the area of the eighth scan. By associating each area with a thinning mask, which will be explained below, it is possible to control the landing order of each ink dot.

[0064] FIG. 13 shows thinning masks used in so-called 8-pass printing, which completes image printing in eight scans. An ink dot is applied when the pixel value of the thinning mask is "1" and the pixel value of the dot data after quantization processing, which indicates whether or not ink is applied, is also "1." The mask in FIG. 13(a) has all pixel values of "0." This indicates that ink is not applied in the scan corresponding to this mask. The thinning masks in FIGS. 13(b) to (e) have mutually exclusive pixel positions of "1," which indicates ink application. Note that thinning masks are used repeatedly in the scan direction of the print head (the X direction in the figure).

[0065] As described above, since the Me ink requires the silver particles to fuse, the Me ink is applied in an earlier scan than the CMYK inks. Therefore, the thinning masks used in the scan order determination process for the Me ink are shown in FIG. 13(b) for the first scan, FIG. 13(c) for the second scan, FIG. 13(d) for the third scan, FIG. 13(e) for the fourth scan, and FIG. 13(a) for the fifth through eighth scans. On the other hand, the thinning masks used for the CMYK inks are shown in FIG. 13(a) for the first through fourth scans, FIG. 13(b) for the fifth scan, FIG. 13(c) for the sixth scan, FIG. 13(d) for the seventh scan, and FIG. 13(e) for the eighth scan. This configuration enables control so that the Me ink is applied first, followed by the colored inks.

[0066] In this embodiment, in steps S706 and S707, the values of the thinning mask used for the CMYK colored inks are changed based on the attribute value indicating the edge of the colored region detected in step S704. This changes the order of scans in which dots of the CMYK colored inks are applied, and makes it possible to control the order in which the ink dots land on the recording medium. The change method involves changing the corresponding pixel value in the source thinning mask to "0" for pixels with an attribute value of "1" indicating a colored region, and changing the corresponding pixel value in the destination thinning mask to "1."

[0067] FIG. 14 shows an example of such a change. The thinning mask of FIG. 13(b), used in the fifth scan for CMYK colored inks, is changed as shown in FIG. 14(b) by referring to the attribute values indicating the edges of the colored areas in FIG. 10. The changed pixels are indicated by diagonal lines slanting upward to the right. Furthermore, the thinning mask of FIG. 13(d), used in the seventh scan, is changed as shown in FIG. 14(c) by referring to the attribute values indicating the edges of the colored areas in FIG. 10. The changed pixels are indicated by diagonal lines slanting upward to the right. As a result, among the pixels with an attribute value of "1" indicating the edge of a colored area, pixels that would have had ink dots applied in the fifth scan in the normal mask processing result are changed to control so that ink dots are applied in the seventh scan.

[0068] Similarly, the thinning mask of FIG. 13(c), used in the sixth scan for CMYK colored inks, is modified as shown in FIG. 14(b) by referring to the attribute values indicating the edges of the colored regions in FIG. 10. The modified pixels are indicated by the diagonal lines sloping downward to the right. Furthermore, the thinning mask of FIG. 13(e), used in the eighth scan, is modified as shown in FIG. 14(d) by referring to the attribute values indicating the edges of the colored regions in FIG. 10. The modified pixels are indicated by the diagonal lines sloping downward to the right. As a result, of the pixels with an attribute value of "1" indicating the edge of a colored region, pixels that would have received ink dots in the sixth scan as a result of normal mask processing are now controlled so that ink dots are instead received in the eighth scan. In other words, from the seventh scan onwards, the number of ink dots to be applied to pixels at the edges of colored regions will be greater than the number of ink dots to be applied to non-edge pixels of colored regions.

[0069] In the example of modification described above, the thinning mask is changed, but a thinning mask to which ink dots are added in the eighth scan may be prepared in advance and switched by referring to the attribute indicating the edge.

[0070] In step S709, the printing operation is carried out in accordance with the printing scan determined in step S708.

[0071] 15 is a schematic diagram showing the state of dots on a recording medium after the change in the ink dot application order. For simplicity's sake, we will assume that the landing order has been changed so that ink is applied to pixels on the edge of colored areas during the eighth scan.

[0072] First, as shown in Figure 15(a), the Me ink is applied from the first scan to the fourth scan and lands on the recording medium. At this point, the silver particles of the Me ink have not yet fused. Then, as shown in Figure 15(b), the colored ink is applied from the fifth scan to the seventh scan, except for the boundary area with the Me ink. During this time, the silver particles of the Me ink fuse. Then, as shown in Figure 15(c), the colored ink is applied to the boundary area with the Me ink at the eighth scan. In this way, the impact time difference between the application of the Me ink and the application of the colored ink at the pixel adjacent to the Me ink is increased. This allows the colored ink to lands at the boundary area adjacent to the Me ink after the silver particles of the Me ink have fused, thereby suppressing the decrease in silver particle density of the Me ink due to the solvent of the adjacent colored ink. In other words, the image degradation caused by insufficient fusion of the Me ink, which appears brown, can be suppressed. This effect can be achieved even if the scan order is changed only for a limited number of pixels. Furthermore, even if the difference in landing time caused by changing the scanning order is only one scan, the effect can still be obtained.

[0073] As described above, if a colored ink lands adjacent to the Me ink immediately after it has been applied, the coloring material of the colored ink may flow into the area of the Me ink, which may cause image defects such as bleeding or color mixing. However, with the processing of this embodiment, even if the coloring material of the colored ink flows in, it does not affect the fusion of the silver particles, so no image defects occur.

[0074] The method for calculating the number of scans to be changed when changing the scan order will be explained below. The number of scans to be moved to a later scan that applies colored ink is P, the print width to be printed is L (inches), the average movement speed of the carriage 116 in one scan is V (seconds / inch), and the time it takes for the silver particles to fuse is T (seconds). The formula for calculating the number of scans to be moved is Equation 1 below. The calculation result is rounded up to the nearest integer. P=T / (V×L) (Formula 1)

[0075] Figure 16 shows the relationship between the amount of Me ink and the fusion time T of silver particles. The impact time T of silver particles is shorter when the amount of Me ink is greater, and longer when the amount of Me ink is less. This is because fusion of silver particles occurs when silver particles stick together, and the higher the density of silver particles, the more likely they are to stick together. The above characteristic is the opposite of the bleeding characteristic of colored ink. Therefore, the greater the amount of Me ink at the boundary portion of the Me ink, the shorter the fusion time T, allowing the colored ink to be applied to the boundary portion with the metallic recording area at an earlier stage. In other words, the time required to delay ink ejection at the edge of the colored area to a later scan can be reduced. The number of scans to delay from the initially determined scan order can also be determined depending on the amount of Me ink at the boundary portion of the Me ink.

[0076] Using Figure 16, we will explain how to calculate the number of scans to change in order to delay the scan order for applying colored inks based on the amount of Me ink. Let T1 be the fusion time of silver particles when the amount of Me ink per unit area is 20, and T2 be the fusion time of silver particles when it is 255. Also, let D be the amount of Me ink in the boundary area. The fusion time T can be calculated using Equation 2 below. Once the fusion time T is found using Equation 2, the number of scans to move can be calculated using Equation 1. T=D×(T2-T1) / (255-20) (Formula 2)

[0077] As a result, if the amount of Me ink at the boundary portion of the Me ink is small, a long time lag is required between the application of the Me ink and the application of the adjacent colored ink, and the scan for applying the colored ink must be slowed down, i.e., the number of scans to be moved must be increased. On the other hand, if the amount of Me ink is large, the time lag between the application of the Me ink and the application of the adjacent colored ink can be short, so the scan for applying the colored ink can be slowed down, i.e., the number of scans to be moved can be reduced. In this way, the fusion time can be calculated based on the amount of Me ink applied, and the destination scan for applying the colored ink can be determined based on the fusion time.

[0078] It goes without saying that there is no need to change the scanning order of all edge pixels, as long as the colored ink is applied after a time equal to or longer than the fusion time T has elapsed since the application of the Me ink. If the difference in landing time between the Me ink applied to a pixel and the colored ink applied to a pixel adjacent to that pixel is shorter than the fusion time T, the next scanning to apply the colored ink should be determined so that the difference in landing time is longer than the fusion time T.

[0079] Generally, the resolution of input image data is smaller than the resolution of dot data after quantization processing. Therefore, if the Me ink amount data is set to the resolution after quantization processing, the data volume will be large. This can result in insufficient access speed to the RAM 112 during high-speed printing. If the access speed is insufficient, data transfer to the print head 115 will be impossible, causing the printing operation to stop. Therefore, in addition to the above, a configuration may be adopted in which the quantization results of the Me ink are referenced to determine whether to delay the scan that applies the colored ink. Since the quantization result shows that the number of 1s per unit area increases as the Me ink amount increases, using the quantization results enables processing with an effect similar to that of the method using Equation 2. Specifically, the following is true: Using Equation 1, P1 is calculated when the Me ink amount is 20, and P2 when the Me ink amount is 255. Next, one of the pixels with an attribute of "1," indicating an edge of a colored area, is designated as the pixel of interest. The quantized data of the Me ink for the eight surrounding pixels, centered on the pixel location of the pixel of interest, is referenced. If the result of the reference is that there is one or fewer pixels with quantized data of "1", the scan is delayed by P1. If there are two or more pixels, the scan is delayed by P2. This configuration makes it possible to reduce the amount of data while controlling the dot landing order according to the amount of Me ink.

[0080] In the above process, the landing order of colored ink dots is shifted by changing the thinning mask used in the scan order determination process using attribute values indicating the edges of colored areas, so that the landing time difference between Me ink and colored ink is equal to or greater than the fusion time. Alternatively, attribute information indicating the edges of colored areas may be added to the quantization process results. The quantization process results may be multi-valued, indicating the number of dots to be ejected within a given area, rather than a binary value indicating whether or not an ink dot is applied. For example, if the input image is 256-valued pixel value data ranging from 0 to 255, the quantization process can be performed to obtain five-valued pixel value data ranging from 0 to 4. Then, multi-valued quantization expansion, which determines where ink dots are applied, generates binary data indicating whether or not an ink dot is applied for each scan. This allows for control of the landing order and placement of ink dots, even when the same quantization value is used.

[0081] Below, we will explain a method for controlling the landing order of ink dots using multi-value quantization expansion processing. First, during quantization processing, the quantization result is changed based on attribute data indicating the edge of a colored region. In this embodiment, if the quantization result is not "0" and the attribute data indicating the edge of a colored region is "1", "4" is added to the quantization result. As a result, if the attribute data indicating the edge of a colored region is "1", i.e., if the pixel is an edge pixel of a colored region, the quantization result of the colored ink will take on a value between "5" and "8".

[0082] FIGS. 20(a) to 20(e) are examples of expansion masks used in multi-value quantization expansion processing, and FIG. 20(f) is a correspondence table for determining whether to apply ink. The expansion masks in FIGS. 21(a) to 21(e) are multi-valued. Using the correspondence table in FIG. 20(f), it is determined whether to apply ink dots based on the quantized value and the expansion mask value corresponding to that pixel position. In the correspondence table in FIG. 20(f), ◯ indicates that an ink dot will be applied, and × indicates that an ink dot will not be applied. For CMYK colored inks, the expansion masks corresponding to each scan correspond to FIG. 20(a) for the first to fourth scans, FIG. 20(b) for the fifth scan, FIG. 20(c) for the sixth scan, FIG. 20(d) for the seventh scan, and FIG. 21(e) for the eighth scan.

[0083] As a result, when the quantization value is between "5" and "8," ink dots are applied during the seventh and eighth scans of the eight printing scans. In other words, because ink dots can be applied to boundary pixels at the edges of colored areas during the latter scans, the difference in landing time between the Me ink and the colored ink increases, and the colored ink lands in the boundary area of the colored area after the silver particles in the Me ink have completely fused. This makes it possible to suppress the image degradation caused by the Me ink appearing brown.

[0084] In the above configuration, in step S704, pixels whose post-filtering value is not "0" are determined to be boundary (edge) pixels, and whether they are edge pixels is determined based on the attribute value of "0" or "1." Alternatively, a Gaussian filter may be used to detect edge strength based on the distance from the edge, and whether to delay the application of colored ink may be determined based on the edge strength. In this case, for attribute data indicating whether a pixel is an edge pixel, pixel values with an attribute value of "1" are converted to "255," and the converted data is subjected to a Gaussian filter. In this embodiment, the purpose is to extract the edges of colored regions to which colored ink is applied, so as a result of the filter processing, pixels that are not in colored regions to which colored ink is applied are set to "0." As a result, the closer the pixel is to the boundary (edge) with the metallic region, the larger the attribute value. Then, a probability mask such as that shown in FIG. 21 is used to switch the execution of the above-mentioned scanning order determination process. Specifically, the probability mask in FIG. 21 is a 16x16 mask, and the mask is repeatedly applied from the top left of the image to determine the value of the probability mask at the position corresponding to the pixel of interest. In other words, the upper left corner of the image is the origin and the position is determined by the x and y coordinates of the pixel of interest. In a 16x16 mask such as that shown in Figure 21, the position of the probability mask corresponding to the pixel of interest is the x coordinate obtained by dividing the x coordinate by 16, and the y coordinate obtained by dividing the y coordinate by 16. The attribute value of the pixel of interest is compared with the corresponding probability mask value, and if the attribute value is larger, the scan order determination process is executed. If the attribute value is smaller, the scan order determination process is not executed. This configuration makes it possible to probabilistically switch pixels for which the ink application scan is delayed based on their distance from the edge.

[0085] In this way, the number of scans by which the ink application scans are delayed increases for pixels that are close to the edge pixels of the metallic region, and the number of scans by which the ink application scans are delayed decreases for pixels that are far from the edge pixels of the metallic region. As a result, the impact time difference between the Me ink and the colored inks can be increased not only for areas determined to be edge pixels of the colored region, but also for pixels that are far from the boundary between the metallic region and the colored region, making it possible to suppress the image defect in which the Me ink appears brown.

[0086] The size and coefficient of the Gaussian filter can be determined based on the bleeding rate of the colored ink. The bleeding rate can be calculated based on the droplet diameter of the ink dot and the dot diameter on the recording medium. The greater the bleeding rate, the farther the colored ink solvent will flow, so it is necessary to increase the landing time difference between the colored ink and the Me ink even at pixels farther from the edge. Therefore, the greater the bleeding rate, the larger the Gaussian filter size and Gaussian coefficient should be. Furthermore, if it is desired to perform the scan order determination process up to a specified edge distance, this can be achieved by processing with a mean value filter instead of a Gaussian filter. The specified edge distance can be controlled by the size of the mean value filter.

[0087] The probability mask shown in Fig. 21 takes values from "0" to "255", but this may be changed depending on the filter size and coefficients. Because the attribute value of an edge pixel may be smaller than 255 depending on the filter coefficient, the minimum value of the attribute value of the edge pixel may be set as the maximum value of the probability mask. This ensures that the scanning order determination process is always performed on the edge pixels.

[0088] Furthermore, attribute values may be changed according to the amount of Me ink for edge pixels on the metallic side adjacent to the boundary between the colored and metallic regions. If the scanning order for only the boundary region is changed by the scanning order determination process, a difference in landing time occurs with respect to pixels that have not been changed. Generally, if the difference in landing time becomes large, the fixing state on the recording medium will differ, which may result in image defects such as color unevenness and gloss unevenness. Therefore, if the amount of Me ink at the edge of the metallic region is large, the proportion of pixels for which scanning is delayed relative to the colored ink edge may be reduced, and if the amount of Me ink is small, the proportion of pixels for which scanning is delayed may be increased.

[0089] Specifically, if the amount of Me ink at the edge of the metallic area is large, the attribute value is decreased, and if the amount of Me ink is small, the attribute value is increased. If the amount of Me ink is M, the attribute value before the change is A, and the attribute value after the change is A', the change can be made using the following formula. A´=A×(255 / M) (Formula 3)

[0090] As a result, the smaller the ink amount at the edge pixels of the metallic region, the greater the number of pixels whose scan order is delayed for application of colored ink, and the greater the ink amount at the edge pixels of the metallic region, the fewer the number of pixels whose scan order is delayed. As a result, in areas close to pixels with a small amount of Me ink at the edge, the number of pixels whose scan order determination process is executed to delay application of colored ink increases, and in areas close to pixels with a large amount of Me ink at the edge, the number of pixels whose scan order determination process is executed to delay application of colored ink decreases. As a result, the scan order can be optimally determined based on the amount of Me ink, and image defects such as the Me ink appearing brown can be suppressed while minimizing unevenness at edge pixels due to differences in landing time.

[0091] (Second embodiment) <Process flow 2> In the first embodiment, the scanning order of colored inks applied to pixels that indicate the edges of colored areas was controlled, but in this embodiment, the order of application of colored ink dots on the boundaries of metallic areas is also controlled.

[0092] As described above, the silver particles of the Me ink applied to the recording medium fuse together, resulting in the development of a metallic luster. Furthermore, by applying a colored ink onto the fused metallic film, a colored metallic luster can be achieved. In typical color metallic recording, the Me ink is fused, followed by the application of a colored ink.

[0093] On the other hand, as described in the above embodiment, the time required for fusion is determined by the density of silver particles in the Me ink. Therefore, the density of silver particles differs between the center and edges of the area where color metallic printing is performed, resulting in different fusion times. Therefore, the fusion time calculated based on the amount of Me ink in the center of the color metallic area is shorter than the fusion time at the edges, which are the boundary between the colored area and the color metallic area. Therefore, applying colored ink before fusion is complete results in an image defect where the boundary with the colored area appears brown.

[0094] FIG. 17 is a flowchart showing the processing in this embodiment. Steps S1701 and S1702 are the same as those in the first embodiment, so their explanation will be omitted. In step S1703, data indicating a metallic region is generated from the Me ink amount generated in step S1702. In this embodiment, an area where the Me ink amount is not "0" is defined as a metallic region. Information as to whether or not it is a metallic region is stored as an attribute value. An attribute value of "1" indicates a metallic region, and an attribute value of "0" indicates a region that is not a metallic region, i.e., a non-metallic region. The attribute values indicating the metallic region for each pixel in order in the X direction, with the upper left corner as the origin, are saved in RAM 112.

[0095] In steps S1704 to S1709, the same processing as that performed in the first embodiment based on the colored region attributes is performed based on the metallic region attributes. That is, the edges of the metallic region to which metallic ink is applied are detected, and the scanning order for applying colored ink to the pixels at the edges of the pixels to which metallic ink is applied is controlled so that the colored ink is applied after the metallic ink has fused to those pixels.

[0096] With this configuration, the scan that applies the colored ink is shifted back relative to the colored ink at the boundary of the metallic region, widening the difference in landing time between the Me ink and the colored ink, so that the colored ink at the metallic boundary lands after the silver particles of the Me ink have fused. This prevents the silver particle density of the Me ink from decreasing due to the solvent of the colored ink applied from above, as described above, and suppresses the image degradation that makes the Me ink appear brown.

[0097] The configuration of this embodiment can be performed in parallel with the processing of the first embodiment. In this case, the attributes of the colored region and the metallic region can be expressed by a single attribute value. Specifically, pixels with an attribute value of "1" indicate colored regions, and pixels with an attribute value of "0" indicate metallic regions. The above-described edge extraction filter can be used to detect the boundaries of each region. In this case, edges with both attribute values of "1" and "0" are extracted, and the attribute value is not referenced to determine whether the edge is determined. This allows the scans that apply colored ink to both colored region boundaries and metallic region boundaries to be delayed, while simultaneously suppressing the image degradation that occurs when Me ink appears brown. Furthermore, by referencing the region attributes, it is possible to determine whether the boundary is a colored region or a metallic region, making it possible to appropriately set the scans of colored ink applied to the edges of each region.

[0098] (Third embodiment) <Process flow 3> In the first embodiment described above, the scan for applying the colored ink is delayed to ensure a difference in landing time between the adjacent Me inks. However, the problem of the present invention can be solved if the adjacent colored inks are applied after the fusion of the Me ink is complete, so the present invention is not limited to a configuration in which the scan for the colored inks is changed.

[0099] In this embodiment, the order in which Me ink is applied to the boundary region of the metallic region is controlled. The scan in which Me ink is applied to pixels at the edge of the metallic region to which Me ink is applied is changed to be earlier than the previous scan. Edge pixels are detected from the pixels to which Me ink is applied, and the scan in which Me ink is applied is advanced to be earlier than the previous scan based on the difference in the number of scans between the scan in which Me ink is applied to the detected edge pixels and the scan in which colored ink is applied to adjacent pixels. This ensures that the Me ink has enough time to fuse, and reduces image defects caused by insufficient fusing.

[0100] 18 is a flowchart showing the processing of this embodiment. Steps S1801 to S1805 are equivalent to those of the second embodiment. In steps S1806 to S1808, the landing order of ink dots is controlled by changing the scan order so that Me ink is applied in a scan that precedes the scan before the change, based on the attribute value indicating the boundary of the metallic region generated in step S1802. In this example, the Me ink that was determined to be applied in the fourth scan after mask processing is changed to be applied in the second scan. Control of the landing order of ink dots is equivalent to steps S1706 to S1708 of the second embodiment.

[0101] FIG. 19 shows the results of modifying the Me ink applied in each scan in this embodiment. The thinning mask in FIG. 13(e), used in the fourth scan of the Me ink, is modified as shown in FIG. 19(d) by referring to the attribute values indicating the edge of the metallic region. The modified pixels are indicated by the diagonal lines slanting upward to the right. Furthermore, the thinning mask in FIG. 13(b), used in the first scan of the Me ink, is modified as shown in FIG. 19(a) by referring to the attribute values indicating the edge of the metallic region. The modified pixels are indicated by the diagonal lines slanting upward to the right. In this way, the dot landing order for the Me ink at the boundary (edge) of the metallic region is shifted to an earlier scan, widening the landing time difference between the Me ink and the colored ink. This allows the colored ink to be applied to the boundary edge of the metallic region after the silver particles of the Me ink have fused, thereby suppressing image degradation due to poor fusion caused by a decrease in the silver particle density of the Me ink due to the solvent of the colored ink that lands later.

[0102] Furthermore, in this embodiment, the configuration of the first embodiment and the configuration of the second embodiment may be executed in parallel. By executing them in parallel, the interval between the landing times of the Me ink and the colored inks is further increased, making it possible to suppress the image degradation that causes the image to appear brown. [Explanation of symbols]

[0103] 109 Image Processing Accelerator 111 CPU 114 Recording head controller 115 Recording head 116 Carriage

Claims

1. a recording means in which a plurality of recording elements for applying a metallic ink containing metal particles are arranged in a first direction, and a plurality of recording elements for applying a colored ink containing a coloring material are arranged in the first direction; a scanning means for relatively scanning the recording means in a second direction intersecting the first direction; a generating means for generating dot data indicating whether or not to apply ink to each pixel for each of N (N: an integer of 2 or more) scans of the recording means and the recording medium; a control means for controlling the recording means and the scanning means based on the dot data generated by the generating means so as to complete recording of an image for each unit area by the N scans; Equipped with The generating means Based on the input data, edge pixels that are pixels to which metallic ink is not applied and that are adjacent to pixels to which metallic ink is applied are detected; generating dot data indicating whether or not to apply ink to each pixel for each of the N scans based on the input data; changing data indicating application of colored ink to the edge pixels in the generated dot data for the Lth scan (L: an integer equal to or greater than 2, and L<N) to dot data for the Mth scan (M: an integer equal to or greater than 3, and L<M≦N); In the dot data of the scan before the Mth scan, data indicating application of metallic ink to pixels adjacent to the edge pixel is generated. An image recording device characterized by:

2. 2. The image recording apparatus according to claim 1, wherein the generating means generates the metallic ink dot data so that application of the metallic ink is completed by the (L-1)th scan.

3. 3. The image recording apparatus according to claim 1, wherein the generating means generates dot data for colored ink so that colored ink is not applied until the (L-1)th scan.

4. The image recording device according to any one of claims 1 to 3, characterized in that the generation means acquires the fusion time of metal particles contained in the metallic ink, and determines the dot data for the Mth scan to be changed based on the acquired fusion time.

5. 5. The image recording apparatus according to claim 4, wherein the fusion time is determined based on the amount of metallic ink applied per unit area.

6. 6. The image recording apparatus according to claim 4, wherein the generating means determines the dot data for the Mth scan to be changed based on the scanning speed of the recording means.

7. The image recording device according to any one of claims 1 to 6, characterized in that the generating means generates quantized data by quantizing the input data, and generates dot data corresponding to each of the N scans using a thinning mask corresponding to each of the N scans on the generated quantized data.

8. 8. The image recording apparatus according to claim 1, wherein the metal particles are silver particles.

9. 9. The image recording apparatus according to claim 1, further comprising a moving unit that moves the recording medium relative to the recording unit in the first direction.

10. a recording means in which a plurality of recording elements for applying a metallic ink containing metal particles are arranged in a first direction, and a plurality of recording elements for applying a colored ink containing a coloring material are arranged in the first direction; a scanning means for relatively scanning the recording means in a second direction intersecting the first direction; a generating means for generating dot data indicating whether or not to apply ink to each pixel for each of N (N: an integer of 2 or more) scans of the recording means and the recording medium; a control means for controlling the recording means and the scanning means based on the dot data generated by the generating means so as to complete recording of an image for each unit area by the N scans; Equipped with The generating means Based on the input data, edge pixels that are pixels to which metallic ink is not applied and that are adjacent to pixels to which metallic ink is applied are detected; quantizing the input data to generate quantized data; modifying pixel values corresponding to the detected edge pixels in the quantized data; generating dot data corresponding to each of the N scans based on the changed quantized data so that data indicating application of colored ink to the edge pixels is dot data for a scan subsequent to a predetermined scan among the N scans; generating data indicating application of metallic ink to pixels adjacent to the edge pixels in dot data of a scan preceding a scan containing data indicating application of colored ink to the edge pixels; An image recording device characterized by:

11. a recording means in which a plurality of recording elements for applying a metallic ink containing metal particles are arranged in a first direction, and a plurality of recording elements for applying a colored ink containing a coloring material are arranged in the first direction; a scanning means for relatively scanning the recording means in a second direction intersecting the first direction; a generating means for generating dot data indicating whether or not to apply ink to each pixel for each of N (N: an integer of 2 or more) scans of the recording means and the recording medium; a control means for controlling the recording means and the scanning means based on the dot data generated by the generating means so as to complete recording of an image for each unit area by the N scans; Equipped with The generating means Detecting pixels at the edge of pixels to which metallic ink is applied based on input data; generating dot data indicating whether or not to apply ink to each pixel for each of the N scans based on the input data; changing the data indicating application of metallic ink to the edge pixels in the generated dot data for the Lth scan (L: an integer equal to or greater than 2, and L<N) to dot data for the Mth scan (M: an integer, and M<L); In the dot data of the scan before the Lth scan, data indicating application of metallic ink to pixels adjacent to the edge pixel is generated. An image recording device characterized by:

12. a recording means in which a plurality of recording elements for applying a metallic ink containing metal particles are arranged in a first direction, and a plurality of recording elements for applying a colored ink containing a coloring material are arranged in the first direction; a scanning means for relatively scanning the recording means in a second direction intersecting the first direction; An image processing method for a recording device comprising: a generating step of generating dot data indicating whether or not to apply ink to each pixel for each of N (N: an integer of 2 or more) scans of the recording means and the recording medium; a control step of controlling the recording means and the scanning means based on the generated dot data so that the recording of an image for each unit area is completed by the N scans; Equipped with In the producing step, Based on the input data, edge pixels that are pixels to which metallic ink is not applied and that are adjacent to pixels to which metallic ink is applied are detected; generating dot data indicating whether or not to apply ink to each pixel for each of the N scans based on the input data; changing data indicating application of colored ink to the edge pixels in the generated dot data for the Lth scan (L: an integer equal to or greater than 2, and L<N) to dot data for the Mth scan (M: an integer equal to or greater than 3, and L<M≦N); In the dot data of the scan before the Mth scan, data indicating application of metallic ink to pixels adjacent to the edge pixel is generated. An image processing method comprising:

13. A program for causing a computer to execute each step of the image processing method according to claim 12.

Images