Information processing device, method, and program

Abstract

To provide an information processing device that appropriately determines arrangement of pixels on which a plurality of kinds of ink with different spectral characteristics are recorded respectively.SOLUTION: The information processing device generates first ink data for performing recording with first ink and second ink data for performing recording with second ink having spectral characteristics different from spectral characteristics of the first ink, on the basis of recording data. The information processing device changes arrangement of pixels on which the first ink is recorded which is determined from data on the first ink and the number of dots for each pixel of the first ink, on the basis of arrangement of pixels on which the first ink is recorded which is set from data on the first ink and arrangement of pixels on which the second ink is recorded which is set from data on the second ink.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to an information processing apparatus, method, and program for processing data used for recording by discharging ink onto a recording medium.

Background Art

[0002] Conventionally, a recording apparatus that records an image using fluorescent ink (hereinafter, "fluorescent ink") and non-fluorescent ink (hereinafter, "non-fluorescent ink") is known. In such a recording apparatus, by using fluorescent ink, it becomes possible to record a highly colorful image having fluorescence. A highly colorful image having fluorescence has high visibility and is used for posters, POP advertisements (Point of purchase advertising) used in storefront promotions in retail stores, and the like.

[0003] As such a recording apparatus, Patent Document 1 describes a method for improving the color development property of an image recorded using fluorescent ink by controlling the ink amount for each path of the fluorescent ink and the non-fluorescent ink and the droplet ejection order when recording using the fluorescent ink and the non-fluorescent ink. Specifically, it is described that, together with the ink amount for each path of the fluorescent ink and the non-fluorescent ink, control is performed such that the fluorescent ink is above the non-fluorescent ink on the recording medium.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When dots of multiple types of ink with different spectral characteristics overlap, the color reproduction of the inks can be inhibited. As a result, color changes may occur in the color gamut reproduced by that combination of inks, potentially leading to a decrease in image quality.

[0006] The present invention aims to provide an information processing apparatus, method, and program for appropriately determining the arrangement of pixels on which multiple types of inks with different spectral characteristics are recorded. [Means for solving the problem]

[0007] To solve the above problems, the information processing apparatus according to the present invention comprises: acquisition means for acquiring recording data; generation means for generating first ink data for recording with a first ink and second ink data for recording with a second ink having spectral characteristics different from the spectral characteristics of the first ink, based on the recording data acquired by the acquisition means; and modification means for changing the arrangement of pixels on which the first ink is recorded, determined from the first ink data, and the number of dots for each pixel of the first ink, based on the arrangement of pixels on which the first ink is recorded, determined from the first ink data, and the arrangement of pixels on which the second ink is recorded, determined from the second ink data. The first ink is a fluorescent ink, and the second ink is a non-fluorescent ink that suppresses the emission of the first ink. If the quantization values ​​of the first ink and the second ink cause an overlap between the pixel on which the first ink is recorded and the pixel on which the second ink is recorded, The modification means ensures that the pixels on which the first ink is recorded and the pixels on which the second ink is recorded do not overlap. Without changing the arrangement of pixels on which the second ink is recorded The arrangement of pixels on which the first ink is recorded is changed, and the changing means is maintained such that the total number of dots of the first ink, determined from the first ink data, is maintained before and after the change by the changing means. Increase the number of pixels on which the first ink is recorded that do not overlap with the pixels on which the second ink is recorded. , The modification means obtains the total number of dots of the first ink from the quantized value of the first ink obtained based on a threshold mask for a predetermined area consisting of multiple pixels, and determines the pixels to increase the number of dots of the first ink based on the order of thresholds defined in the threshold mask. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, the arrangement of pixels on which each of several types of inks with different spectral characteristics are recorded can be appropriately determined. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing the configuration of the recording system. [Figure 2] This is a diagram illustrating the recording head. [Figure 3] This diagram shows the arrangement of the nozzle rows. [Figure 4] This figure shows the intensity of the excitation wavelength and the intensity of the emission wavelength. [Figure 5] This diagram illustrates each scan step. [Figure 6] This flowchart shows the entire recording process. [Figure 7] This flowchart shows the process for determining the dot arrangement of fluorescent ink. [Figure 8] This is a diagram illustrating an example of a 4x4 pixel area. [Figure 9] This is a diagram illustrating an example of a 4x4 pixel area. [Figure 10] This is a diagram illustrating an example of a 4x4 pixel area. [Figure 11] This flowchart shows the process for determining the dot arrangement of fluorescent ink. [Figure 12] This is a diagram illustrating an example of a 4x4 pixel area. [Figure 13] This diagram shows the ratio of pixels to dots. [Figure 14] This flowchart shows the process for determining the dot placement of light ink. [Modes for carrying out the invention]

[0010] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0011] [First Embodiment] For the terms used in this embodiment, they shall be defined as follows.

[0012] (Recording) "Recording" refers not only to the case of forming significant information such as characters and figures, but also regardless of whether it is significant or not. "Recording" represents forming an image, pattern, pattern, etc. on a recording medium widely, regardless of whether it is manifested so that it can be perceived visually by humans. Or, "recording" represents the case of processing a recording medium.

[0013] (Recording Medium) "Recording medium" refers not only to paper used in general recording devices, but also widely represents materials that can receive ink, such as cloth, plastic film, metal plate, glass, ceramics, wood, leather, etc.

[0014] (Ink) "Ink" should be interpreted widely in the same way as the above definition of "recording". "Ink" represents a medium containing a recording material that can be used for forming an image, pattern, pattern, etc., processing the recording medium, or processing the ink by being applied on the recording medium. Note that the processing of ink is, for example, the coagulation or insolubilization of a colorant in the ink applied to the recording medium.

[0015] (Nozzle) "Nozzle" refers to the discharge port of the recording head, unless otherwise specified. Inside the nozzle, there are a communicating liquid passage and an element that generates energy used for ink ejection.

[0016] (Scanning) In order to perform recording on the recording medium, the recording head scans on the recording medium to perform recording. Here, for recording or for the movement of the recording head during acceleration and deceleration related to recording, it is called "scanning".

[0017] (Reciprocating Recording) "Round-trip recording" refers to recording while moving the recording head back and forth across the recording medium surface. Round-trip scanning, round-trip recording, bidirectional scanning, and bidirectional recording all refer to the same thing.

[0018] (Color gamut) "Color gamut" is also called the color reproduction range, color space, or gamut. Generally, "color gamut" refers to the range of colors that can be reproduced in any color space. The color space volume is an indicator that represents the size of this color gamut. The color space volume is the three-dimensional volume in any color space. The chromaticity points that make up the color gamut can be discrete. For example, a specific color gamut may be represented by 729 points on CIE-L*a*b*, and the points in between may be determined using known interpolation operations such as tetrahedron interpolation or cubic interpolation. In such cases, the corresponding color space volume can be obtained by calculating and accumulating the volumes of tetrahedra, cubes, etc., on CIE-L*a*b* that make up the color gamut, corresponding to the interpolation operation method. The color gamut and color space in this embodiment are not limited to a specific color space, but in this embodiment, the color gamut in the CIE-L*a*b* space is described as an example. Furthermore, the numerical values ​​for the color gamut in this embodiment represent the volume calculated cumulatively in CIE-L*a*b* space, assuming tetrahedral interpolation.

[0019] <Entire recording system> Figure 1 is a block diagram showing the configuration of the recording system in this embodiment. PC101 is a general-purpose information processing device such as a PC, for example, a host PC or a tablet PC is used. CPU102 comprehensively controls PC101 by reading programs stored in HDD104 into RAM103 as a work area and executing them. For example, CPU102 obtains commands from the user via HID (Human Interface Device) I / F106 or a touch panel (not shown). Then, PC101 generates recording data that can be processed by the recording device 108 based on the obtained commands and programs stored in HDD104 and transfers it to the recording device 108. In addition, CPU102 performs predetermined processing on the recording data obtained from the recording device 108 via data transfer I / F107, for example, according to the program stored in HDD104, such as data format conversion. Based on the results of the predetermined processing, CPU102 displays the results on a display (not shown) via display I / F105.

[0020] In the recording device 108, the CPU 111 comprehensively controls the recording device 108 by reading programs stored in ROM 113 into RAM 112, which serves as a work area, and executing them. The image processing accelerator 109 is hardware capable of performing image processing at a faster speed than the CPU 111. The image processing accelerator 109 is started when the CPU 111 writes the parameters and data necessary for image processing to a predetermined address in RAM 112. After reading the above parameters and data, the image processing accelerator 109 performs image processing on that data. Alternatively, the CPU 111 may perform equivalent processing instead of the image processing accelerator 109. The above parameters may be stored in ROM 113, or in storage such as flash memory or an HDD (not shown).

[0021] Here, we will describe the image processing performed by the CPU 111 or the image processing accelerator 109. Image processing is, for example, the process of generating data indicating the ink dot formation position in each scan by the recording head 115 based on the acquired recording data. The CPU 111 or the image processing accelerator 109 performs color conversion processing and quantization processing of the acquired recording data.

[0022] The color conversion process is a process of color separation to the ink densities handled by the recording device 108. For example, the acquired recording data includes image data representing an image and fluorescent data for fluorescent recording. If the image data represents an image using color space coordinates such as sRGB, which is the color representation of the monitor, the data representing the image using those sRGB color coordinates (R, G, B) is converted to non-fluorescent ink data (CMYK, described later) handled by the recording device 108. Alternatively, it is converted to ink data containing fluorescent ink colors (CMYKF, described later) handled by the recording device 108. Fluorescent data is converted to fluorescent ink data. Furthermore, if there is both data representing an image using sRGB color coordinates (R, G, B) and fluorescent data, it is converted to both non-fluorescent ink data (CMYK) and fluorescent ink data. Alternatively, it is converted to both ink data containing fluorescent ink colors (CMYKF) and fluorescent ink data. In that case, two planes of fluorescent ink data will be generated. The color conversion method is realized by matrix calculation processing, processing using three-dimensional LUTs (lookup tables), four-dimensional LUTs, etc.

[0023] The recording device 108 of this embodiment uses, as an example, black (K), cyan (C), magenta (M), yellow (Y), and fluorescent (F) inks. Therefore, RGB signal image data and fluorescent data are converted into image data consisting of 8-bit color signals for each of K, C, M, Y, and F. Each color signal corresponds to the amount of each ink applied. In addition, although five colors, K, C, M, Y, and F, have been given as an example of the number of ink colors, other ink colors such as light cyan (Lc), light magenta (Lm), and gray (Gy) inks with low density may be used to improve image quality. In that case, ink data corresponding to those colors will be generated. In this embodiment, light cyan (Lc), light magenta (Lm), and gray (Gy) inks will also be described as non-fluorescent inks. Furthermore, achromatic inks such as black (K) and gray (Gy) will also be described as non-fluorescent inks.

[0024] After the color conversion process, the ink data is subjected to quantization. Quantization is a process that reduces the number of gradation levels in the ink data. In this embodiment, quantization is performed using a dither matrix, which is an array of thresholds for comparing with the ink data values ​​for each pixel. After the quantization process, binary data is ultimately generated that indicates whether or not a dot is formed at each dot formation position.

[0025] After image processing, the recording head controller 114 transfers binary data to the recording head 115. Simultaneously, the CPU 111 controls the recording process via the recording head controller 114, operating the carriage motor to move the recording head 115 and the transport motor to transport the recording medium. As the recording head 115 scans the recording medium and ink droplets are ejected from the recording head 115 onto the recording medium, an image is formed on the recording medium.

[0026] When recording using multiple scans, a scan order determination process is performed after predetermined image processing. The scan order determination process involves downsampling the quantized data using a mask pattern or the like to generate data corresponding to each scan. At this time, the image processing accelerator 109 may be used to speed up the process.

[0027] The PC 101 and the recording device 108 are connected via a communication line 100. In this embodiment, a LAN (Local Area Network) is described as an example of the communication line 100, but it may also be a USB hub, a wireless communication network using a wireless access point, or a connection using Wi-Fi Direct communication function. Furthermore, at least some of the blocks of the recording device 108 may be composed of the PC 101, or the PC 101 and each block of the recording device 108 may be realized as a single device.

[0028] Hereinafter, the recording head 115 will be described as having a total of five recording nozzle rows, consisting of four color inks: cyan (C), magenta (M), yellow (Y), and black (K), and one fluorescent ink: fluorescent pink (FP). In addition to fluorescent pink, the fluorescent ink may also be fluorescent red (FR), fluorescent yellow (FY), fluorescent green (FG), or fluorescent blue (FB).

[0029] <Regarding the recording head of the recording device> Figure 2 is a diagram illustrating the recording head 115. In this embodiment, an image is recorded in multiple scans of N times for a unit area of ​​one nozzle row. The recording head 115 has a carriage 116, nozzle rows 115k, 115c, 115m, 115y, and 115FP, and an optical sensor 118. Nozzle row 115k corresponds to black, nozzle row 115c to cyan, nozzle row 115m to magenta, nozzle row 115y to yellow, and nozzle row 115FP to fluorescent pink. The carriage 116, which is equipped with the five nozzle rows 115k, 115c, 115m, 115y, and 115FP and the optical sensor 118, is capable of reciprocating along the X direction (main scanning direction) in the figure by the driving force of a carriage motor transmitted via a belt 117. As the carriage 116 moves in the X direction relative to the recording medium, ink droplets are ejected from each nozzle in the nozzle row in the direction of gravity (in the -z direction in the figure) based on the recorded data. This records an image equivalent to 1 / N main scans onto the recording medium placed on the platen 119. Once one main scan is completed, the recording medium is transported along the transport direction intersecting the main scan direction (in the -y direction in the figure) for a distance corresponding to the width of 1 / N main scans. Through these operations, an image equivalent to the width of one nozzle row is recorded in N scans. By repeatedly alternating between these main scans and transport operations, an image is gradually formed on the recording medium. Image recording for a predetermined area is completed through the control described above.

[0030] Figure 5 is a diagram illustrating an example of each scan corresponding to the nozzle position. The scanning proceeds from upstream in the transport direction (Y direction) of the recording medium, through the first scan area, the second scan area, and finally the eighth scan area. The recording resolution in the X direction is determined by the ejection frequency and the carriage movement speed. The recording resolution in the Y direction is determined by the nozzle resolution of the recording head 115. In this embodiment, for example, both recording resolutions are set to 600 [dpi]. Therefore, the ejected ink droplets are recorded with a resolution of 600 [dpi] in both the vertical and horizontal directions. The optical sensor 118 performs detection operations while moving together with the carriage 116 to determine the presence or absence of a recording medium on the platen 119.

[0031] <Explanation of the recording head> Figure 3 shows the arrangement of the nozzle rows when the recording head 115 is viewed from the top surface (-z direction) of the recording device 108. The recording head 115 has five nozzle rows arranged at different positions in the X direction. Specifically, there is a nozzle row 115C corresponding to C ink, a nozzle row 115M corresponding to M ink, a nozzle row 115Y corresponding to Y ink, a nozzle row 115K corresponding to K ink, and a nozzle row 115FP corresponding to FP ink. Ink droplets of C ink are ejected from the nozzles of nozzle row 115C. Ink droplets of M ink are ejected from the nozzles of nozzle row 115M. Ink droplets of Y ink are ejected from the nozzles of nozzle row 115Y. Ink droplets of K ink are ejected from the nozzles of nozzle row 115K. Ink droplets of FP ink are ejected from nozzle row 115FP. In each nozzle row, multiple nozzles for ejecting ink droplets are arranged at a predetermined pitch along the Y direction. With such a recording head 115, it is possible to apply fluorescent ink and non-fluorescent ink to the recording medium.

[0032] In this embodiment, not only a recording device that performs multiple scans as described above, but also a recording device using a full-line recording head may be used. The nozzle row of the full-line recording head has a length corresponding to the width of the recording medium, and the nozzles are arranged in a direction perpendicular to the transport direction of the recording medium. A recording head is formed by arranging nozzle rows that eject different types of ink in parallel along the transport direction. The recording medium is transported in a direction perpendicular to the nozzle row by the rotation of transport rollers driven by a motor. While the recording medium is being transported, ink droplets are ejected from the nozzles of multiple colors of the recording head at a frequency corresponding to the transport speed of the recording medium. As a result, ink dots of each color are recorded at a predetermined resolution, and an image for one page of the recording medium is formed.

[0033] <About the characteristics of fluorescent inks and subtractive color mixing inks> Fluorescent colorants are colorants that produce color by absorbing light of an excitation wavelength from their ground state to become excited, and then emitting light of an emission wavelength to return to their ground state. Figure 4 is a graph showing the intensity of the excitation wavelength 401 and the emission wavelength 402 when fluorescent pink ink is recorded on a recording medium. In Figure 4, the horizontal axis represents the wavelength of light, and the vertical axis represents the intensity. The graph in Figure 4 shows the intensity of each light when the wavelength of light shining on the recording sample and the wavelength of light received from the sample are changed.

[0034] The emission wavelength 402 represents the intensity of light received from the recording sample at each wavelength when the recording sample is irradiated with light of the excitation wavelength. Figure 4 shows the case when the recording sample is irradiated with light of 480 nm. The excitation wavelength 401 represents the intensity of the received light when the wavelength of the light irradiated onto the recording sample is changed while the wavelength of the received light is fixed. Figure 4 shows the case when the wavelength of the received light is fixed at 600 nm. As shown in Figure 4, the excitation wavelength range of the fluorescent ink recorded on the recording medium overlaps with the emission wavelength range and is on the shorter wavelength side. In addition, the excitation wavelength 401 has varying intensity at each wavelength, with some wavelengths emitting light efficiently and others not. Furthermore, since fluorescent colorants emit light, the reflectance at the emission wavelength is often greater than 1. In this embodiment, a colorant having the above characteristics is called a fluorescent colorant.

[0035] The excitation and emission of fluorescent pink ink were described above, but in this embodiment, fluorescent inks that emit light at other wavelengths may be used. For example, fluorescent blue ink that emits light in the blue region (450 nm to 500 nm) may be used, or fluorescent green ink that emits light in the green region (500 nm to 565 nm) may be used. Furthermore, fluorescent yellow ink that emits light in the yellow region (565 nm to 590 nm) may be used, or fluorescent orange ink or fluorescent red ink that emit light in the red region (590 nm to 780 nm) may be used. Furthermore, fluorescent inks that combine the above may be used. For example, fluorescent yellow ink that emits light in a region combining the yellow and red regions may be used. Furthermore, the color tone may be adjusted by combining fluorescent inks with different excitation wavelength intensities. For example, fluorescent pink that emits light in the orange region, with weak excitation in the blue region and strong excitation in the green region, may be used.

[0036] In this embodiment, non-fluorescent inks are referred to as subtractive color mixing inks. That is, inks that absorb light of a specific wavelength from the light they are exposed to and do not emit light are called subtractive color mixing inks. For example, subtractive color mixing inks have spectral reflectances as shown for cyan ink 403, magenta ink 404, and yellow ink 405 in Figure 4. The graph in Figure 4 shows the spectral characteristics based on the results measured using a method for measuring spectral reflectance. Unlike fluorescent inks, subtractive color mixing inks only absorb light, so their reflectance never exceeds 1. In this embodiment, black ink is also included as a type of subtractive color mixing ink, but it is not necessary to include black ink.

[0037] Next, the mixing of fluorescent ink and subtractive color mixing ink on a recording medium will be explained using Figure 4. In this figure, at least a portion of the excitation wavelength range of the fluorescent pink ink is within the absorption wavelength range of the yellow ink. When fluorescent pink ink and yellow ink 405 are mixed, the yellow ink absorbs light in the wavelength range of the excitation wavelength 401 of the fluorescent pink ink. Therefore, the fluorescent pink ink cannot be sufficiently excited because the light that would excite it is absorbed by the yellow ink, and its emission is suppressed.

[0038] Furthermore, at least a portion of the emission wavelength range of the fluorescent pink ink falls within the absorption wavelength range of the cyan ink. When fluorescent pink ink and cyan ink 403 are mixed, the cyan ink absorbs light in the wavelength range of the fluorescent pink ink's emission wavelength 402. As a result, the light emitted by the fluorescent pink ink is absorbed by the cyan ink, suppressing its emission.

[0039] Furthermore, at least a portion of the excitation wavelength range of the fluorescent pink ink falls within the absorption wavelength range of the magenta ink. When fluorescent pink ink and magenta ink 404 are mixed, the magenta ink absorbs light in the wavelength range where the fluorescent pink ink is highly sensitive to excitation. As a result, the fluorescent pink ink cannot be sufficiently excited, and its emission is suppressed. In addition, the light emitted by the fluorescent pink ink is absorbed by the magenta ink, further suppressing its emission.

[0040] When fluorescent pink ink and black ink (not shown) are mixed, the black ink absorbs light in the wavelength range of 401, which is the excitation wavelength of the fluorescent pink ink, and also absorbs light in the wavelength range of 402, which is the emission wavelength. As a result, the fluorescent pink ink cannot be sufficiently excited, and its emission is also suppressed.

[0041] In other words, when fluorescent pink ink is mixed with subtractive color mixing ink, the contribution of the fluorescent pink ink to the color development decreases. This characteristic is also greatly influenced by the relative positions of the fluorescent ink and the subtractive color mixing ink on the recording medium. When the ink layer of the fluorescent ink is lower than the ink layer of the subtractive color mixing ink, it is more strongly influenced by the subtractive color mixing ink. As a result, the contribution of the fluorescent pink ink to the color development is also smaller when the fluorescent ink is lower than the subtractive color mixing ink compared to when it is higher.

[0042] <About fluorescent ink> Next, the fluorescent ink used in this embodiment will be described. In this embodiment, a fluorescent ink prepared by mixing a dispersion of a colorant having fluorescent properties with a solvent and an activator is used. The dispersion of fluorescent colorant used in this embodiment is the dispersion of a colorant having fluorescent properties described above. For example, NKW-3207E (fluorescent pink aqueous dispersion: Nippon Fluorescent Chemical Co., Ltd.) or NKW-3205E (fluorescent yellow aqueous dispersion: Nippon Fluorescent Chemical Co., Ltd.) are used, but any dispersion of a colorant having fluorescent properties will suffice.

[0043] The above-mentioned fluorescent colorant dispersion is dispersed in an ink by combining it with a known solvent and activator. The dispersion method of the fluorescent colorant dispersion is not particularly limited. For example, a fluorescent colorant dispersion dispersed with a surfactant, a resin-dispersed fluorescent colorant dispersion dispersed with a dispersion resin, etc., can be used. Of course, it is also possible to use a combination of fluorescent colorant dispersions with different dispersion methods. The surfactant can be anionic, nonionic, cationic, or amphoteric activators. Any water-soluble or water-dispersible resin can be used as the dispersion resin, but among them, a dispersion resin with a weight-average molecular weight of 1,000 to 100,000, and more preferably 3,000 to 50,000, is preferred. As for the solvent, it is preferable to use an aqueous medium containing, for example, water and a water-soluble organic solvent.

[0044] <Recording medium> The recording medium in this embodiment has a substrate and at least one ink-receiving layer. In this embodiment, for example, a recording medium for recording using an inkjet recording method is used. In this embodiment, for example, glossy paper is used as the recording medium and pigment ink is used as the colorant.

[0045] <Multiple colors using fluorescent ink and subtractive color mixing ink> In colors composed of multiple subtractive inks (hereinafter also referred to as "multi-colors"), even if the absorption wavelengths of each color interfere, only the absorption rate of light at the absorption wavelength increases, and it does not hinder the absorption of other colors. However, in multi-colors composed of fluorescent ink and subtractive ink, as mentioned above, the emission of fluorescent ink is suppressed. Therefore, the contribution of fluorescent ink to color development decreases sharply, resulting in a steeper color change compared to multi-colors composed of only subtractive inks. As a result, false contour image artifacts occur.

[0046] Figures 9(A) to 9(D) schematically show the number of dots and dot arrangement for multi-colored inks with different amounts of fluorescent ink and cyan ink when using a conventional method. The percentages in the figures are set to 100% when one dot is ejected to all 4x4 pixels = 16 pixels. Figure 9(A) schematically shows the number of dots and dot arrangement when the amount of fluorescent ink is 75% and the amount of cyan ink is 50%. Figure 9(B) schematically shows the number of dots and dot arrangement when the amount of fluorescent ink is 75% and the amount of cyan ink is 75%. Figure 9(C) schematically shows the number of dots and dot arrangement when the amount of fluorescent ink is 50% and the amount of cyan ink is 50%. Figure 9(D) schematically shows the number of dots and dot arrangement when the amount of fluorescent ink is 50% and the amount of cyan ink is 75%.

[0047] In Figure 9(C), when both inks are at 50%, there is no overlap between the fluorescent and cyan ink dots. However, in Figures 9(A), 9(B), and 9(D), overlap between the fluorescent and cyan ink dots occurs. As a result, as mentioned above, the luminescence of the fluorescent ink is suppressed.

[0048] Figure 6 is a flowchart showing the overall recording process in this embodiment. In this embodiment, the process in Figure 6 allows for recording control to suppress abrupt color changes in the secondary colors of fluorescent ink and subtractive color mixing ink. The process in Figure 6 is realized, for example, by the CPU 111 reading a program stored in ROM 113 into RAM 112 and executing it. Alternatively, the process in Figure 6 may be executed by the image processing accelerator 109.

[0049] In S101, the CPU 111 receives recording data transmitted from the PC 101. The recording data includes either RGB data or CMYK data. In S102, the CPU 111 generates subtractive color mixing ink data and fluorescent ink data from the recording data acquired in S101. Note that the fluorescent ink data may be acquired as separate data from the recording data.

[0050] In S103, the CPU 111 performs output gamma correction according to the dot coverage on the recording medium. S102 to S103 correspond to the color conversion process described above and are repeated for each pixel. In S104, the CPU 111 performs the quantization process described above.

[0051] In S105, the CPU 111 performs a process to determine the dot positions of the fluorescent ink based on the quantization results in S104. The process for determining the dot positions of the fluorescent ink will be described later, but a process is performed to change the dot arrangement of the fluorescent ink determined from the fluorescent ink data. In S106, the CPU 111 controls the recording head 115 to perform recording based on the dot positions and number of ejected dots of the subtractive color mixing ink and the dot positions and number of ejected dots of the fluorescent ink determined in S105.

[0052] The above process suppresses abrupt color changes in the secondary color transitions of the fluorescent ink and subtractive color mixing ink. However, if the fluorescent ink is added to the complementary color gamut to the emission wavelength of the fluorescent ink, the color gamut that can be recorded by the recording device 108 will decrease. Therefore, in this embodiment, the fluorescent ink data in S102 is generated in a predetermined color gamut based on the emission wavelength of the fluorescent ink. The process of determining the dot arrangement of the fluorescent ink in S105 will be explained with reference to Figure 7.

[0053] Figure 7 is a flowchart showing the process for determining the dot arrangement of fluorescent ink. The process in Figure 7 determines the dot arrangement of fluorescent ink based on the dot arrangement of subtractive color mixing ink. In this embodiment, the dot arrangement is determined such that there is at least one pixel to which two or more fluorescent ink dots are applied, and there are no pixels to which both fluorescent ink dots and subtractive color mixing ink dots are applied.

[0054] In S201, the CPU 111 calculates the number of fluorescent ink dots K within a predetermined region from the quantization results in S104. In this embodiment, for the sake of simplicity, the case of a 4x4 pixel region will be described.

[0055] Figure 8(A) schematically shows the fluorescent ink quantity data processed in S103 in a 4x4 pixel area as an example. Figure 8(B) schematically shows the quantization result data of the fluorescent ink processed in S104. Figure 8(D) schematically shows the threshold mask used in the quantization process of S104. In S104, the quantization result shown in Figure 8(B) is output using the fluorescent ink quantity data in Figure 8(A) and the threshold mask in Figure 8(D). Calculating the number of fluorescent ink dots K means, for example, calculating the sum of the quantization values ​​(total number of dots) within a 4x4 pixel area. In the case of the quantization result data of the fluorescent ink shown in Figure 8(B), the number of fluorescent ink dots K = 10.

[0056] In S202, CPU111 generates a fluorescent ink dot generation flag. Figure 8(E) schematically shows the fluorescent ink dot generation flag processed in S202 for a 4x4 pixel area as an example. "1" indicates that a dot will be generated, and "0" indicates that no dot will be generated. The fluorescent ink dot generation flag is generated based on the amount of fluorescent ink in Figure 8(A) and the dot arrangement of subtractive color mixing inks that constitute the secondary color. In Figure 8(E), pixels that have a fluorescent ink amount but no subtractive color mixing ink dots are set to "1", and all other pixels are set to "0". Figure 8(C) schematically shows the quantization result of a cyan dot as an example. From the quantization result of the cyan dot in Figure 8(C) and the amount of fluorescent ink in Figure 8(A), the fluorescent ink dot generation flag shown in Figure 8(E) is generated.

[0057] In S203, the CPU 111 determines the processing pixels within the 4x4 pixel area. The processing pixels are determined in ascending order of threshold values ​​from the threshold mask in Figure 8(D). For example, in Figure 8(D), the pixel corresponding to threshold "1" is determined first as the processing pixel. In S203, the CPU 111 determines whether the fluorescent dot generation flag generated in S202, which corresponds to the processing pixel determined in S203, is "1". If the fluorescent dot generation flag is determined to be "1", that is, if there is a quantity of fluorescent ink and no subtractive color mixing ink dots, the process proceeds to S205. On the other hand, if the fluorescent dot generation flag is not "1", that is, if it is determined to be "0", the process proceeds to S206.

[0058] In S205, CPU111 changes the quantization value of the fluorescent ink dots. Changing the quantization value here means increasing the quantization value of the processing pixel by 1. Then, CPU111 decreases the number of fluorescent ink dots K by 1. After S205, the process proceeds to S206.

[0059] In S206, the CPU 111 determines whether the number of fluorescent ink dots K is zero or not. If it is determined that the number of fluorescent ink dots K is zero, the processing in the 4x4 pixel area is terminated and the processing moves on to the next 4x4 pixel area. For example, the processing in Figure 7 is executed for the 4x4 pixel area adjacent to the 4x4 pixel area that was being processed in Figure 7. On the other hand, if it is determined that the number of fluorescent ink dots K is not zero, the next pixel to be processed is determined in S203. That is, in the case of Figure 8(D), the pixel corresponding to the threshold "2" is determined as the pixel to be processed. Then, the processing from S204 onwards is repeated.

[0060] The following describes the process from S203 onwards, referring to Figure 8. For the processing pixel corresponding to the threshold "1" determined in S203, the fluorescent ink dot generation flag is "0". Therefore, the process proceeds from S204 to S206. In this case, the quantization value of the fluorescent ink dot becomes "0". This is because, in Figure 8(E), the fluorescent ink dot generation flag for that processing pixel is "0", meaning that if a fluorescent ink dot is generated, it will overlap with the cyan dot. Therefore, even if the quantization value in Figure 8(B) is not "0", it is set to "0". The same applies to pixels whose quantization value is "0" from here on.

[0061] For the processing pixel corresponding to the threshold "2", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot is "0".

[0062] For the processing pixel corresponding to the threshold "3", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0063] For the processing pixel corresponding to the threshold "4", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot is "0".

[0064] For the processing pixel corresponding to the threshold "5", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. In this case, the quantization value of the fluorescent ink dot becomes "2", which is the quantization value "1" in Figure 8(B) plus 1. Then, the number of fluorescent ink dots K becomes 10-1=9.

[0065] For the processing pixel corresponding to the threshold "6", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0066] For the processing pixel corresponding to the threshold "7", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. In this case, the quantization value of the fluorescent ink dot becomes 2, which is the quantization value "1" in Figure 8(B) plus 1. Then, the number of fluorescent ink dots K becomes 9-1=8.

[0067] For the processing pixel corresponding to the threshold "8", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot is "0".

[0068] For the processing pixel corresponding to the threshold "9", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. In this case, the quantization value of the fluorescent ink dot becomes "2", which is the quantization value "1" in Figure 8(B) plus 1. Then, the number of fluorescent ink dots K becomes 8-1=7.

[0069] For the processing pixel corresponding to the threshold "10", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0070] For the processing pixel corresponding to the threshold "11", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. In this case, the quantization value of the fluorescent ink dot becomes "1", which is obtained by adding 1 to the quantization value "0" in Figure 8(B). Then, the number of fluorescent ink dots K becomes 7-1=6.

[0071] For the processing pixel corresponding to the threshold "12", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. In this case, the quantization value of the fluorescent ink dot becomes "1", which is obtained by adding 1 to the quantization value "0" in Figure 8(B). Then, the number of fluorescent ink dots K becomes 6-1=5.

[0072] For the processing pixel corresponding to the threshold "13", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. In this case, the quantization value of the fluorescent ink dot becomes "1", which is obtained by adding 1 to the quantization value "0" in Figure 8(B). Then, the number of fluorescent ink dots K becomes 5-1=4.

[0073] For the processing pixel corresponding to the threshold "14", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0074] For the processing pixel corresponding to the threshold "15", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0075] For the processing pixel corresponding to the threshold "16", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0076] Here, the sum of the new quantization values ​​of the fluorescent ink dots is 9. On the other hand, the sum of the quantization values ​​of the fluorescent ink dots obtained from S201, i.e., the number of fluorescent ink dots K, is 10. In other words, the sum of the new quantization values ​​of the fluorescent ink dots, 9, does not reach the original sum of the quantization values ​​of the fluorescent ink dots, 10. Therefore, it is necessary to allocate the difference of 1 in the quantization values ​​to one of the pixels. In S206, if it is determined that the decremented number of fluorescent ink dots K is not zero, the process from S203 is repeated so that the sum of the new quantization values ​​of the fluorescent ink dots reaches the original sum of the quantization values ​​of the fluorescent ink dots.

[0077] Again, for the processing pixel corresponding to the threshold "1" determined in S203, the fluorescent ink dot generation flag is 0. Therefore, the process proceeds from S204 to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0078] For the processing pixel corresponding to threshold "2", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0". The same applies to thresholds 2 to 4.

[0079] For the processing pixel corresponding to the threshold "5", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. Here, the current quantization value of the fluorescent ink dot in the processing pixel is "2", and the limit on the number of dots that can be generated in one pixel is 2. In this embodiment, in this case, the quantization value of the fluorescent ink dot in the processing pixel is not increased by 1, and the process proceeds to the next processing pixel. That is, the quantization value of the fluorescent ink dot in the processing pixel remains "2". Then, the number of fluorescent ink dots K becomes 4-1=3.

[0080] For the processing pixel corresponding to the threshold "6", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0081] For the processing pixel corresponding to the threshold "7", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. Here, the current quantization value of the fluorescent ink dot in the processing pixel is "2", and the limit on the number of dots that can be generated in one pixel is 2. Therefore, the quantization value of the fluorescent ink dot in the processing pixel is not increased by 1, and the process proceeds to the next processing pixel. That is, the quantization value of the fluorescent ink dot in the processing pixel remains "2". The number of fluorescent ink dots K becomes 3-1=2.

[0082] For the processing pixel corresponding to the threshold "8", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot is "0".

[0083] For the processing pixel corresponding to the threshold "9", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. Here, the current quantization value of the fluorescent ink dot in the processing pixel is "2", and the limit on the number of dots that can be generated in one pixel is 2. Therefore, the quantization value of the fluorescent ink dot in the processing pixel is not increased by 1, and the process proceeds to the next processing pixel. That is, the quantization value of the fluorescent ink dot in the processing pixel remains "2". The number of fluorescent ink dots K becomes 2-1=1.

[0084] For the processing pixel corresponding to the threshold "10", the fluorescent ink dot generation flag is "0", so the process proceeds to S206. In this case, the quantization value of the fluorescent ink dot becomes "0".

[0085] For the processing pixel corresponding to the threshold "11", the fluorescent ink dot generation flag is "1", so the process proceeds to S205. Here, the current quantization value of the fluorescent ink dot in the processing pixel is 1, which is not reached the limit of 2 dots that can be generated in one pixel. Therefore, the quantization value of the fluorescent ink dot becomes "2", which is the quantization value "1" plus 1. Then, the number of fluorescent ink dots K becomes 1-1=0. Here, in S206, it is determined that the number of fluorescent ink dots K is 0, and the processing shown in Figure 7 for the 4x4 pixel region is terminated.

[0086] Figure 8(F) schematically shows the number of fluorescent ink dots and their arrangement as a result of the above processing. As shown in Figure 8(F), the fluorescent ink dots are positioned so as not to overlap with the cyan dots. Furthermore, the positions where multiple dots with a quantization value of "2" are placed are determined in order of increasing threshold in the threshold mask. This is because, in S203, when determining the processing pixels, they are processed in order of increasing threshold. In this embodiment, the positions where multiple dots are placed can be determined based on the threshold mask. With such a configuration, the positions where multiple dots are placed can be determined while maintaining the blue noise characteristics of the threshold mask, thereby improving the granularity.

[0087] Through the above process, the number of dots to be applied within a predetermined area of ​​the fluorescent ink and subtractive color mixing ink, as well as the pixel positions where the dots are applied, can be determined. Furthermore, since it is determined that fluorescent ink dots and subtractive color mixing ink dots are not applied to the same pixel, the emission of the fluorescent ink is not suppressed by the subtractive color mixing ink. As a result, abrupt changes in the color transition of the multiple colors of the fluorescent ink and subtractive color mixing ink can be suppressed.

[0088] Figure 10 schematically shows the number of dots and pixel positions to which secondary colors are assigned when the amount of fluorescent ink and cyan ink differs in this embodiment. The percentages in the figures are values ​​where 100% is the case when one dot is ejected to all pixel positions within a predetermined area. Figure 10(A) schematically shows the number of dots and pixel positions to which they are assigned when the amount of fluorescent ink is 75% and the amount of cyan ink is 50%. Figure 10(B) schematically shows the number of dots and pixel positions to which they are assigned when the amount of fluorescent ink is 75% and the amount of cyan ink is 75%. Figure 10(C) schematically shows the number of dots and pixel positions to which they are assigned when the amount of fluorescent ink is 50% and the amount of cyan ink is 50%. Figure 10(D) schematically shows the number of dots and pixel positions to which they are assigned when the amount of fluorescent ink is 50% and the amount of cyan ink is 75%.

[0089] In Figure 10(C), when both inks are at 50%, the result is the same as in Figure 9(C). On the other hand, in Figures 10(A), 10(B), and 10(D), the pixel positions and number of fluorescent ink dots are determined so that the cyan dots and fluorescent ink dots do not overlap. Furthermore, by adding two or more fluorescent ink dots to the same pixel position, it is possible to maintain the luminescence of the fluorescent ink while avoiding luminescence suppression by subtractive color mixing inks.

[0090] This section explains the number of pixels to which fluorescent ink dots are applied and the number of dots applied. If T is the number of pixels to which dots are applied and D is the number of dots applied, the ratio W of the number of pixels to which dots are applied is calculated as shown in equation (1).

[0091] W = T / D ···(1) Hereinafter, the case within a predetermined region will be described using specific examples. When the predetermined region is a 4×4 pixel region, the number of pixels L within the predetermined region is 16 pixels. In this embodiment, the predetermined region is a 4×4 pixel region, but it is not limited thereto. The number of pixels L may be any natural number of 2 or more.

[0092] The number of pixels P to which the fluorescent ink is applied in FIG. 9(B) is 12 locations. Also, the number of dots M to which the fluorescent ink is applied is 12 dots. For the cyan ink dots which are subtractive color mixing inks, the number of pixels Q to which they are applied is also 12 locations, and the number of dots N to which they are applied is 12 dots. That is, the ratio W of the number of pixels to the number of dots applied is calculated as follows for both the fluorescent ink and the subtractive color mixing ink.

[0093] The number of pixels P to which the fluorescent ink is applied in FIG. 9(B) is 12 locations. Also, the number of dots M to which the fluorescent ink is applied is 12 dots. For the cyan ink dots which are subtractive color mixing inks, the number of pixels Q to which they are applied is also 12 locations, and the number of dots N to which they are applied is 12 dots. That is, the ratio W of the number of pixels to the number of dots applied is calculated as follows for both the fluorescent ink and the subtractive color mixing ink. W = 12 / 12 = 1.0 On the other hand, in FIG. 10(B), the cyan ink remains the same, which is 1.0. However, for the fluorescent ink, the number of pixels P to which dots are applied is 4 locations. The number of dots M to which the fluorescent ink is applied is 𝟏𝟐 dots, and the ratio W of the number of pixels to the number of dots applied is calculated as follows.

[0094] W = 4 / 12 = 0.25 The ratio W of the fluorescent ink is less than 1.0. When M≧1 and M + N>L and M<L and N<L, that is, when the total number of dots applied for the colors constituting the secondary color exceeds 100%, and the number of dots applied for each of the fluorescent ink and the subtractive color mixing ink is less than the number of pixels L within the predetermined region. In such a case, when 1 or more dots of the fluorescent ink dots are applied to 1 pixel, the ratio W of the fluorescent ink is less than 1.0. Further, the ratio W = M / P of the fluorescent ink is smaller than the ratio W = N / Q of the subtractive color mixing ink. In the above, the number of dots M applied for the fluorescent ink, the number of pixels P, the number of dots N applied for the subtractive color mixing ink, and the number of pixels Q are natural numbers.

[0095] As described above, in this embodiment, the ratio of the number of pixels assigned to the number of assigned dots is controlled to be small so that the fluorescent ink dots do not overlap with the subtractive color mixing ink dots. With such a configuration, abrupt changes can be suppressed in the color change of the multiple colors of the fluorescent ink and the subtractive color mixing ink.

[0096] [Second Embodiment] The second embodiment will now be described in terms of its differences from the first embodiment. In the first embodiment, the pixel position to which fluorescent ink dots are applied was controlled so that the fluorescent ink dots do not overlap with subtractive color mixing ink dots. Depending on the number of scans of the recording head 115, there is an upper limit to the number of dots that can be applied at the same pixel position. For example, if there are 8 scans, the number of dots applied at the same pixel position will be 8 dots. When it is necessary to reduce the number of scans in order to record at high speed, it is possible to achieve both high-speed recording processing and suppression of abrupt color changes between the multiple colors of fluorescent ink and subtractive color mixing ink. Therefore, in this embodiment, processing will be described when there is an upper limit to the number of dots that can be applied at the same pixel position. In the first embodiment, when there is a limit to the number of dots for a processing pixel, processing was described in which the quantization values ​​of other processing pixels that have not yet reached the limit and do not overlap with subtractive color mixing ink dots were added. In this embodiment, other forms of processing will be described when there is a limit to the number of dots for a processing pixel.

[0097] Figure 11 is a flowchart showing the overall recording process in this embodiment. In this embodiment, the process in Figure 11 allows for recording control to suppress abrupt color changes in the secondary colors of fluorescent ink and subtractive color mixing ink, even when there is an upper limit on the number of dots assigned at the same pixel position. The process in Figure 11 is realized, for example, by the CPU 111 reading a program stored in ROM 113 into RAM 112 and executing it. Alternatively, the process in Figure 11 may be executed by the image processing accelerator 109. Sections S301 to S306 are the same as those described in S201 to S206, so their descriptions are omitted.

[0098] In S307, the CPU 111 determines whether the quantized value exceeds the upper limit of the number of dots. Specifically, for example, a dot count conversion table corresponding to the quantized value may be stored in advance, and the number of dots may be calculated from the quantized value by performing the conversion using that table. The determination in S307 may also be made by comparing the calculated number of dots with the upper limit of the number of dots determined based on the number of scans of the recording head 115. If it is determined that the value exceeds the upper limit of the number of dots, the process proceeds to S308. If it is determined that the value does not exceed the upper limit of the number of dots, the process proceeds to S306.

[0099] In S308, the CPU 111 changes the fluorescent dot generation flag. The pixels targeted for this change are those adjacent to the currently focused processing pixel. Adjacent pixels are any pixels on the recording medium surface that are adjacent in the main scanning direction and the transport direction and whose fluorescent dot generation flag is "0". The CPU 111 changes the fluorescent dot generation flag of the adjacent pixels from "0" to "1". Changing from "0" to "1" increases the quantization value of the fluorescent ink. As a result, a fluorescent ink dot is ejected at that pixel. Figure 12(A) schematically shows the quantization value when the above process is executed. Pixels 1201, 1202, 1203, and 1204 in Figure 12(A) show that the fluorescent ink dot generation flag has been changed from "0" to "1". At pixels 1201 to 1204, fluorescent ink dots are also generated at the pixel positions where cyan dots are applied. Furthermore, the generated fluorescent ink dots are adjacent to pixel positions where cyan ink dots are not applied, namely pixels 1205, 1206, 1207, and 1208. In other words, if the condition of being adjacent to a pixel position where cyan dots are not applied is met, fluorescent ink dots can also be generated at pixel positions where cyan dots are applied. With this dot arrangement, even if cyan ink dots and fluorescent ink dots overlap when ejected at pixels 1201-1204, the fluorescent ink can bleed into adjacent pixels 1205-1208 where cyan ink dots do not exist. Therefore, inhibition of fluorescent ink emission in cyan ink can be suppressed. As a result, even if there is an upper limit on the number of dots at the same pixel position, recording can be controlled to suppress abrupt color changes in the secondary colors of fluorescent ink and subtractive color mixing ink.

[0100] Figure 13 is a graph showing the ratio W of the number of pixels assigned to the number of assigned dots when there is an upper limit on the number of dots. Figure 13 shows the graph when the upper limit on the number of assigned dots is 2. The horizontal axis represents the number of assigned dots for fluorescent ink dots and subtractive color mixing ink dots, and the vertical axis represents the ratio W of the number of assigned pixels to the number of assigned dots in a 4x4 pixel area. When the number of assigned dots on the horizontal axis is 4, it indicates that 4 dots are assigned for fluorescent ink and 4 dots are assigned for subtractive color mixing ink. The dotted line shows the conventional change, and the solid line shows the change in this embodiment.

[0101] As shown in Figure 13, when the number of dots each of fluorescent ink and subtractive color mixing ink is 8, the ratio W of the number of pixels to which fluorescent ink is applied relative to the number of dots is 1.0. Subsequently, as the number of applied dots increases, the ratio W decreases. When the number of fluorescent ink dots and subtractive color mixing ink dots each reach 11, the dot limit of 2 is reached. Subsequently, as the number of applied dots increases, fluorescent ink dots are also generated at the pixel positions where subtractive color mixing ink dots are applied, as described above, so the ratio W increases. Therefore, the coverage rate of ink dots on the recording medium surface can be improved.

[0102] Even when the maximum number of dots is reached, by controlling the pixel position where the fluorescent ink dots are added to a pixel position adjacent to a position where no subtractive color mixing ink dots exist, it is possible to suppress abrupt changes in the color transition of the multiple colors of the fluorescent ink and subtractive color mixing ink.

[0103] [Third Embodiment] The third embodiment will be described below in terms of its differences from the first and second embodiments. In this embodiment, when recording is performed using light ink, the control of the dot arrangement of subtractive color mixing ink when the number of dots at the same pixel position reaches the upper limit will be described. The process of this embodiment will be described below with reference to Figure 12(B).

[0104] Figure 12(B) schematically shows the quantization values ​​of fluorescent ink, cyan ink (dark cyan ink), and light cyan ink when the fluorescent ink is 75% and the cyan ink is 75%. In this embodiment, we will explain the case where the colorant concentration of the light cyan ink is half that of the cyan ink. Since the colorant concentration of the light cyan ink is half that of the cyan ink, the number of ejected dots at 25% of the cyan ink is converted to the number of ejected dots at 50% of the light cyan ink. That is, the quantization value at 75% of the cyan ink shown in Figure 12(A) is replaced with the quantization value at 50% of the cyan ink and the quantization value at 50% of the light cyan ink shown in Figure 12(B). Then, the same processing as in Figure 7 of the first embodiment is performed on the fluorescent ink dots and cyan ink dots.

[0105] The dot arrangement of the fluorescent ink in Figure 12(B) shows the result of performing the processing in Figure 7 on the fluorescent ink dots and cyan ink dots. As shown in the dot arrangement of the fluorescent ink, the fluorescent ink dots do not overlap with the cyan ink dots. On the other hand, there is overlap between the fluorescent ink dots and the light cyan ink dots. However, the light cyan ink has a lower light absorption rate compared to the cyan ink. Therefore, the suppression of fluorescent ink emission by subtractive color mixing ink is also halved. In this embodiment, by converting at least one dot of the number of dark ink dots to the number of light ink dots, the number of pixels to which dark ink is applied is reduced and the number of pixels to which light ink is applied is increased. As a result, the suppression of fluorescent ink emission is reduced, and abrupt changes in the color change of the multiple colors of the fluorescent ink and subtractive color mixing ink can be suppressed.

[0106] As shown in Figure 12(B), if the pigment density of the light cyan ink is half that of the cyan ink, the number of light ink dots for each dark ink dot will be 2. The conversion of the number of dots may be changed depending on the difference in pigment density between the cyan ink and the light cyan ink. The larger the difference in pigment density, the more light ink dots there will be for each dark ink dot. Conversely, the smaller the difference in pigment density, the fewer light ink dots there will be for each dark ink dot. Even in this case, the same effects as in the first and second embodiments can be achieved by replacing the subtractive color mixing ink dots with subtractive color mixing ink dots with high pigment density and subtractive color mixing ink dots with low pigment density, and by controlling the landing position of the fluorescent ink dots relative to the high-pigment-density subtractive color mixing ink.

[0107] [Fourth Embodiment] The third embodiment will now be described in terms of its differences from the first to third embodiments. In this embodiment, the dot arrangement is controlled to suppress abrupt color changes in the secondary colors of light and dark inks. The process of this embodiment will now be explained using Figure 14.

[0108] Dark cyan ink and light cyan ink absorb light in the same wavelength range. This is because at least a portion of the absorption wavelength range of light cyan ink falls within the absorption wavelength range of dark cyan ink. Therefore, when dark cyan ink and light cyan ink are recorded together, the absorption of light cyan ink is suppressed by the dark cyan ink. As a result, the gradual color change in light cyan ink is suppressed. Here, "light ink" refers to ink with a low pigment density. Examples include light cyan (Lc), light magenta (Lm), and gray (Gy) inks. On the other hand, "dark ink" refers to ink with a high pigment density. Examples include black (K), cyan (C), and magenta (M) inks.

[0109] Figure 14 is a flowchart showing the process for determining the dot arrangement of light ink. The process in Figure 14 allows the dot arrangement of light ink to be determined based on the dot arrangement of dark ink. In this embodiment, the dot arrangement is determined such that there is at least one pixel to which two or more light ink dots are applied, and there are no pixels to which both light and dark ink dots are applied.

[0110] In S401, the CPU 111 calculates the number of faint ink dots X in a predetermined area from the quantization result in S104. In this embodiment, for the sake of simplicity, the case of a 4x4 pixel area will be described.

[0111] The treatment for the fluorescent ink described in the first embodiment is applied to the light ink in this embodiment, and the treatment for the cyan ink described in the first embodiment is applied to the dark ink in this embodiment. Hereinafter, the fluorescent ink in Figures 8(A) to (F) will be described as the light ink, and the cyan ink as the dark ink.

[0112] In S402, the CPU 111 generates a light ink dot generation flag. That is, as in the first embodiment, "1" indicates that a dot will be generated, and "0" indicates that no dot will be generated. The light ink dot generation flag is generated based on the amount of light ink and the arrangement of dark ink dots in Figure 8(A). In Figure 8(E), pixels that have a light ink amount and no dark ink dots are set to "1", and all other pixels are set to "0". From the quantization results of the dark ink dots in Figure 8(C) and the amount of light ink in Figure 8(A), the light ink dot generation flag shown in Figure 8(E) is generated.

[0113] In S403, the CPU 111 determines the processing pixels within the 4x4 pixel area. The processing pixels are determined in ascending order of threshold values ​​from the threshold mask in Figure 8(D). For example, in Figure 8(D), the pixel corresponding to threshold "1" is determined first as the processing pixel. In S403, the CPU 111 determines whether the light ink dot generation flag generated in S402, which corresponds to the processing pixel determined in S403, is "1". If the light ink dot generation flag is determined to be "1", that is, if there is a light ink amount and no dark ink dots, the process proceeds to S405. On the other hand, if the light ink dot generation flag is not "1", that is, if it is determined to be "0", the process proceeds to S406.

[0114] In S405, CPU111 changes the quantization value of the faint ink dots. Changing the quantization value here means increasing the quantization value of the processing pixel by 1. Then, CPU111 decreases the number of faint ink dots X by 1. After S405, the process proceeds to S406.

[0115] In S406, the CPU 111 determines whether the number of faint ink dots X is zero or not. If it is determined that the number of faint ink dots X is zero, the processing in the 4x4 pixel area is terminated and the processing moves on to the next 4x4 pixel area. For example, the processing in Figure 14 is executed for the 4x4 pixel area adjacent to the 4x4 pixel area that was being processed in Figure 14. On the other hand, if it is determined that the number of faint ink dots X is not zero, the next pixel to be processed is determined in S403. That is, the pixel corresponding to the threshold "2" is determined as the pixel to be processed. Then, the processing from S404 onwards is repeated.

[0116] The above process controls the placement of light ink dots at pixel locations that do not overlap with dark ink dots. Furthermore, the positions of pixels where multiple light ink dots are placed are determined in order of increasing threshold in the threshold mask. Therefore, it is possible to determine the positions where multiple dots are placed while maintaining the blue noise characteristics of the threshold mask, thereby improving the graininess. In this embodiment, the pixel area is set to 4x4, but it is not limited to this, and any 2x2 or larger is acceptable.

[0117] As described above, according to this embodiment, the dot arrangement is determined so that both light and dark ink dots are not applied to the same pixel, thereby preventing the gradual color change of light ink due to dark ink from being suppressed. As a result, abrupt color changes can be suppressed in the dual color of light and dark ink.

[0118] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0119] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0120] 101 PC: 108 Recording device: 102, 111 CPU: 103, 112 RAM: 115 Recording head

Claims

1. A means of acquiring recorded data, Based on the recording data acquired by the acquisition means, a generation means generates first ink data for recording with a first ink and second ink data for recording with a second ink having spectral characteristics different from those of the first ink. A changing means for changing the arrangement of pixels on which the first ink is recorded and the number of dots for each pixel of the first ink, based on the arrangement of pixels on which the first ink is recorded, determined from the first ink data, and the arrangement of pixels on which the second ink is recorded, determined from the second ink data. Equipped with, The first ink is a fluorescent ink, and the second ink is a non-fluorescent ink that suppresses the emission of light from the first ink. If the quantization values ​​of the first ink and the second ink result in an overlap between the pixel on which the first ink is recorded and the pixel on which the second ink is recorded, The modification means modifies the arrangement of pixels on which the first ink is recorded without changing the arrangement of pixels on which the second ink is recorded, so that the pixels on which the first ink is recorded and the pixels on which the second ink is recorded do not overlap. The modifying means increases the number of dots of pixels on which the first ink is recorded that do not overlap with pixels on which the second ink is recorded, so that the total number of dots of the first ink determined from the first ink data is maintained before and after the modification by the modifying means. The modification means obtains the total number of dots of the first ink from the quantized value of the first ink obtained based on a threshold mask for a predetermined area consisting of multiple pixels, and determines the pixels to increase the number of dots of the first ink based on the order of thresholds defined in the threshold mask. An information processing device characterized by the following:

2. The information processing apparatus according to claim 1, characterized in that the arrangement of pixels on which the second ink is recorded, determined from the second ink data, is obtained from the quantization value of the second ink in the predetermined area.

3. The modification means identifies a pixel on which the first ink, determined from the first ink data, is recorded and a pixel on which the second ink, determined from the second ink data, is recorded, and The number of dots of the first ink corresponding to the identified pixel is assigned to the pixels other than the identified pixel. The information processing apparatus according to claim 1 or 2.

4. The information processing apparatus according to claim 3, characterized in that the modifying means determines the identified pixel as the pixel on which the first ink is recorded if the specified pixel satisfies the conditions.

5. The information processing apparatus according to claim 4, characterized in that the condition is that the identified pixel is adjacent to a pixel on which the second ink is not recorded.

6. When the arrangement of pixels on which the second ink is recorded and the number of dots of the second ink are converted to the arrangement of pixels on which dark ink is recorded and the number of dots of the dark ink, and the arrangement of pixels on which light ink is recorded and the number of dots of the light ink, The modification means modifies the arrangement of the pixels on which the first ink is recorded so that the pixels on which the first ink is recorded and the pixels on which the dark ink is recorded do not overlap. The information processing apparatus according to any one of claims 1 to 5.

7. The information processing apparatus according to claim 6, characterized in that the pixels on which the first ink is recorded and the pixels on which the light ink is recorded may overlap.

8. The information processing apparatus according to any one of claims 1 to 7, characterized in that the first ink is fluorescent pink ink, and the second ink is yellow ink, cyan ink, or magenta ink.

9. The information processing apparatus according to any one of claims 1 to 8, further comprising control means for controlling recording means to record on a recording medium using the first ink and the second ink, based on the arrangement of pixels on which the first ink is recorded and the number of dots per pixel of the first ink, as modified by the modification means.

10. A method performed in an information processing device, The acquisition process for obtaining recorded data, Based on the recording data acquired in the acquisition step, a generation step is provided to generate first ink data for recording with a first ink and second ink data for recording with a second ink having spectral characteristics different from those of the first ink. A modification step of changing the arrangement of pixels on which the first ink is recorded and the number of dots for each pixel of the first ink, based on the arrangement of pixels on which the first ink is recorded, determined from the first ink data, and the arrangement of pixels on which the second ink is recorded, determined from the second ink data. It has, The first ink is a fluorescent ink, and the second ink is a non-fluorescent ink that suppresses the emission of light from the first ink. If the quantization values ​​of the first ink and the second ink result in an overlap between the pixel on which the first ink is recorded and the pixel on which the second ink is recorded, In the modification step, the arrangement of pixels on which the first ink is recorded is changed without changing the arrangement of pixels on which the second ink is recorded, so that the pixels on which the first ink is recorded and the pixels on which the second ink is recorded do not overlap. In the modification step, the number of dots of pixels on which the first ink is recorded that do not overlap with pixels on which the second ink is recorded is increased so that the total number of dots of the first ink determined from the first ink data is maintained before and after the modification in the modification step. In the modification step, the total number of dots of the first ink is obtained from the quantized value of the first ink, which is obtained based on a threshold mask for a predetermined area consisting of multiple pixels, and the pixels on which the number of dots of the first ink is increased are determined based on the order of thresholds defined in the threshold mask. A method characterized by the following:

11. A program for operating a computer as one of the means of the information processing apparatus according to any one of claims 1 to 9.

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