Image processing device, image processing method, and program

Abstract

To solve the problem in which: when an image is recorded by using basic color ink and specific color ink, if the amount of ink applied to a recording medium exceeds an amount that can be received by the recording medium, the ink overflows and image quality is reduced; in this case, the amount of application of the ink can be reduced to prevent the overflow of the ink, however, which may cause a variation in color balance.SOLUTION: The amount of application of specific color ink, of a plurality of colors of ink applied to a recording medium, is preferentially reduced to prevent a change in color balance while preventing overflow of ink.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] Nowadays, users of recording devices (printers) are becoming increasingly diversified. Users with a high level of proficiency with recording devices record test patches on a recording medium and adjust the amount of ink applied themselves. On the other hand, printer vendors who understand the characteristics of recording devices and inks provide conversion tables that adjust the amount of ink applied to users with a low level of proficiency. By using such conversion tables, users with a low level of proficiency can adjust the color within a range of the amount of ink applied so that the amount of ink applied on the recording medium is not too great.

[0003] When using a conversion table, the ink ratio in a secondary color image reproduced using multiple ink colors is selected from the range provided by the printer vendor. However, there is an increasing demand to set the application amount of each ink color at a ratio different from the ink ratio provided by the conversion table.

[0004] Patent Document 1 describes a method for reducing the design load of a lookup table by calculating the total amount of ink applied and limiting the amount of ink applied so that the total amount is equal to or less than a preset limit value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-186711 A Summary of the Invention [Problem to be solved by the invention]

[0006] By implementing the application amount limiting process described in Patent Document 1, the total amount of ink applied to the recording medium is kept below the limit value, making it possible to prevent overflow. However, there is a possibility that the color tone of the recorded matter will change significantly due to a change in the ink ratio.

[0007] In response to such problems, the present invention aims to suppress ink overflow on a recording medium by limiting the amount of ink applied, while suppressing fluctuations in color balance in the recorded image by limiting the amount of ink applied. [Means for solving the problem]

[0008] The present invention relates to a recording apparatus for recording an image by applying a plurality of colors of ink, the plurality of colors being at least one basic color ink and a fluorescent ink containing a dispersion having fluorescent properties, onto a recording medium, the apparatus comprising: an acquisition means for acquiring a color signal including a plurality of elements that indicate the amount of each of the plurality of colors of ink applied; a determination means for determining whether or not a total value of the plurality of elements included in the color signal is greater than a threshold value; and, when it is determined that the total value is greater than the threshold value, a reduction means for reducing the total value after the reduction so that the total value is less than the total value before the reduction. Color Signal and a reduction means for reducing the value of at least one of the plurality of elements included in the color signal, wherein in the reduction process by the reduction means, the amount by which the value of the element corresponding to the fluorescent ink is reduced is the largest among the plurality of elements included in the color signal. Effect of the Invention

[0009] According to the present invention, the amount of ink applied of a specific color is preferentially reduced, so that it is possible to suppress changes in color balance in a printed image while also suppressing ink overflow. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of an overall outline of a recording system. [Diagram 2] A diagram showing an example of UI information for design software [Diagram 3]A diagram showing an example of plate making process carried out by RIP software. [Figure 4] Block diagram showing the control configuration of the inkjet printing system [Diagram 5] FIG. 1 is a side cross-sectional view illustrating a configuration of a printing unit of an inkjet printing apparatus. [Figure 6] FIG. 1 shows an example of a processing configuration of a recording system. [Figure 7] Flowchart of grant amount excess determination process in the first embodiment [Figure 8] A table showing the relationship between the ink ID, ink name, and application amount for a given pixel. [Figure 9] Flowchart of grant amount limiting process in the first embodiment [Figure 10] Intensity plot versus wavelength when recorded on a recording medium [Figure 11] Gonioreflectance characteristics of subtractive and fluorescent inks [Figure 12] Example of a lookup table used in ink separations [Figure 13] Flowchart of grant amount limiting process in the second embodiment [Figure 14] Example of a lookup table used in ink separations [Figure 15] ΔE graph when changing ambient light DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] 1 shows an example of a recording system applicable to this embodiment. A printer 104 that functions as an image processing device is connected to a PC 101. The PC 101 can start design software 102 and can edit image data to be recorded by the printer 104. The image data created by the design software 102 is transferred to RIP software 103. The RIP software 103 carries out plate making processing and color management processing.

[0013] This figure shows an example in which the design software 102 and the RIP software 103 are started in the PC 101, but they may be started in another PC. In many cases, a user who creates and edits image data is different from a user who performs editing to record on a recording medium. In such a case, the RIP software and the printer are executed in the PC of the printing company. The design software 102 may be, for example, Illustrator or software dedicated to a specific model, and the software is not limited. The design software 102 and the RIP software 103 may be integrated. Also, the RIP software 103 may be built in the printer 104. Various communication forms, such as wired USB or Gigabit-Ethernet, and wireless Wi-Fi, can be applied between the PC 101 and the printer 104. Since the communication form affects the productivity of the printer, it is desirable to be able to select the communication form according to the productivity of the printer expected by the user.

[0014] FIG. 2 is an example of the UI of the design software 102. In this figure, a screen 201 shows the entire screen for editing image data. Image data 202 is the image data to be edited that is being displayed, and has a signal value of P indicating fluorescent pink in addition to the signal values ​​of R, G, and B. In this figure, a layer of (R, G, B, P) depicting a human face and a layer of (R, G, B, P) of a balloon with the text "POSTER" written on it are included. A pointer 203 is a pointer that is operated on a window when a user uses a mouse to edit the design software. A pixel value 204 is a pixel value of the data pointed to by the pointer 203. In the example of this figure, the pointer 203 points to a balloon with the text "POSTER" written on the display screen 202. The pixel values ​​of the balloon are (190, 64, 64, 0) for each of the signal values ​​(R, G, B, P).

[0015] The text edit button 205 is a button for superimposing text data on image data when editing with design software, and for example, the text "POSTER" written on the display screen 202 can be added or the content of the text can be changed. The mouse change button 206 is a button for changing the pointer 203 to another pointer, and for example, the pointer 203 can be changed to a rectangular frame for specifying the area of ​​the entire speech bubble. The zoom button 207 is a button for zooming in and out of the information displayed on the display screen 202. The color change button 208 is a button for changing the pixel value information of the data pointed to by the pointer 203. When the color change button 208 is pressed, the screen transitions, or a swatch screen 209 is displayed as a separate screen.

[0016] When the pointer 203 designates a patch from the swatch, the corresponding pixel value 210 is displayed. In this figure, the signal values ​​(R, G, B, P) of the patch pointed to by the pointer 203 are (255, 255, 0, 153).

[0017] The pixel value information obtained as the pixel value 204 and the pixel value 210 is not limited to (R, G, B, P). For example, it may be a color signal including each element of (C, M, Y, K, P). It may also be a color signal including each element of (C, Lc, M, Lm, Y, Lm, K, Lk, P). In the case of information other than R, G, B, the given pixel value may correspond to the density on the recording medium. The swatch patch in this figure shows a cross patch in which the signal value of P (fluorescent pink) changes on the horizontal axis and the signal values ​​of R, G, and B change on the vertical axis, but is not limited to such a patch display method. The pixel value information indicated by the pixel value 210 can be manually set to a specified value by the user himself. If the pixel value manually set by the user is used frequently, it can be preset in the swatch.

[0018] The method by which the user specifies the density of fluorescent pink can be either by using the swatch expression method described above or by directly specifying a numerical value.

[0019] The design software 102 sends the created image data to the RIP software 103. In the example shown in the figure, the created image data includes data for four colors: R, G, B, and P. It is also possible for the design software 102 to create two or more sheets of image data and send the two or more sheets of image data to the RIP software 103. It is assumed that the area marked "POSTER" on the display screen 202 is superimposed on a background on which a person's face is displayed. In this case, the image data containing the person's face and the image data marked "POSTER" are each sent to the RIP software 103. The RIP software makes plates from the multiple sheets of image data sent to it and transfers one sheet of image data to the printer 104.

[0020] FIG. 3 is an example of platemaking for data input to the RIP software 103. The platemaking process generates one sheet's worth of (R, G, B, P) image data from multiple layers. This platemaking process mainly involves three processes: "knockout," "overprint," and "multiplication." This figure shows examples of platemaking in two cases. In case 1, RGB data and fluorescent pink data are input. In case 2, two types of RGB data are input to make it easier to understand the changes in the means of implementing the platemaking process.

[0021] Knockout prioritizes foreground data in all image planes over overlap. In Case 1, if the signal value of the foreground fluorescent pink data is 0, the signal value of the overlapping area will be output as 0 even if the signal value of the background is 255. A user may wish to knockout when, for example, they want to expose foreground data.

[0022] Overprinting prioritizes foreground data over overlap, and adopts background data when the signal value of the image plane of the foreground data is 0. In Case 1, the signal value of the foreground fluorescent pink data is 0, so the background signal value of 255 is adopted as the output value of the overlap area. A user may wish to overprint if, for example, they want to suppress misregistration.

[0023] Multiplication is performed by using a formula that determines the signal values ​​of the foreground data and background data for the overlap. The formula differs depending on the software. For example, the output result shown in this figure was calculated using the following formula 1.

[0024] Output signal value = (1 × foreground data) × (1 × background data) ÷ 255 (Formula 1) A user may wish to perform multiplication, for example, when he or she wishes to obtain a watermark effect.

[0025] The overprint and multiply are intended to utilize background data without overwriting with foreground data. For example, this is effective when you want to obtain not only the gradation of color inks, but also the glow effect of fluorescent pink ink obtained from fluorescent pink data 202.

[0026] 4 is a block diagram showing an example of the configuration of the printer 104. The printer 104 in this embodiment is composed of a recording unit 401 and an image processing unit 402. Image data supplied from the RIP software 103 is subjected to predetermined image processing in the image processing unit 402, and then sent to the recording unit 401 and recorded.

[0027] In the recording unit 401, the recording unit main control unit 403 controls the entire recording unit 401, and is composed of a CPU, a ROM, a RAM, and the like. In addition, since the CPU can operate the hardware circuit of the ASIC as one end of the control means, the ASIC may be included as a component. The recording buffer 404 can store image data before being transferred to the recording head 405 as raster data. The recording head 405 is an inkjet type recording head having a plurality of nozzles capable of ejecting ink as droplets, and ejects ink from each nozzle according to the image data stored in the recording buffer 404. In this embodiment, five nozzle rows corresponding to a total of five colors of ink, namely cyan (C), magenta (M), yellow (Y), and black (K) as basic colors, and fluorescent pink (P) as a specific color, are arranged on the recording head 405. Note that the number of ink colors is not limited to the above, and the basic colors are not limited to the above colors. As the basic color, for example, a nozzle row for ejecting any one of light cyan ink, light magenta ink, and gray ink may be further mounted. As the specific color ink, a nozzle row for any one of red, green, and blue ink may be mounted, and as the fluorescent color ink, a nozzle row for fluorescent yellow ink may be mounted. Furthermore, a silver ink, an embossed ink, and a clear ink having a function other than reproducing colors on a recording medium may be further mounted. As the specific color, a metallic ink containing metal particles may be provided instead of fluorescent pink ink.

[0028] A feed / discharge motor control unit 406 controls the transportation, feeding, and discharge of the recording medium, and controls the position of the recording medium so that ink ejected from the recording head 405 hits an accurate position. The start / stop operation of the motor is also performed, taking into consideration the case where the recording head 405 has a multi-pass configuration.

[0029] The recording unit interface (I / F) 207 transmits and receives data signals to and from the image processing unit 402, and the two are connected by an I / F signal line 417. The type of I / F signal line 417 may be, for example, one conforming to Centronics specifications. A data buffer 408 temporarily stores image data received from the image processing unit 402. An operation unit 409 has a mechanism for allowing a developer to operate commands. A system bus 410 connects the various functions of the recording unit 401.

[0030] On the other hand, in the image processing unit 402, the image processing unit main control unit 411 includes a CPU, a ROM, a RAM, etc., and performs various processes on the image supplied from the RIP software 103 in order to generate image data that can be recorded by the recording unit 401. In addition, since the CPU can operate the hardware circuit of the ASIC as one end of the control means, the ASIC may be included as a component. The lookup table and matrix to be used are pre-recorded in the ROM in the image processing unit main control unit 411 for each type of recording medium and print mode. The image processing unit interface (I / F) 412 exchanges data signals with the recording unit 401. The external connection interface (I / F) 416 exchanges image data and the like with the RIP software 103 connected by an I / F signal line 417. The display unit 413 displays various information to the user, and can be, for example, an LCD. The operation unit 414 is a mechanism for the user to perform command operations, and can be, for example, a keyboard or a mouse. The system bus 415 connects the image processing unit main control unit to each function.

[0031] FIG. 5A is a side cross-sectional view for explaining the configuration of an inkjet recording device, which is a printer 104. A carriage 501 carrying a recording head 405 having nozzle rows for each ink color and an optical sensor 506 moves back and forth in the X direction in the figure by the driving force of a carriage motor transmitted via a belt 505. While the carriage 501 moves in the X direction relative to the recording medium, ink droplets are ejected in the Z direction from each nozzle provided in the recording head 405 according to the recording data. By this ejection operation, ink is applied onto the recording medium placed on a platen 504, and an image for one scan is recorded. When one recording scan is completed, a conveying operation is performed in the Y direction (conveying direction) intersecting with the X direction in the figure by an amount corresponding to the recording width of the image for one scan. By alternately repeating such recording scans and conveying operations multiple times, an image is formed on the recording medium.

[0032] The optical sensor 506 detects whether or not a recording medium is present on the platen 504 by performing a detection operation while moving together with the carriage 501. In the scanning area of ​​the carriage 501 but at a position away from the platen 504, a recovery means for performing maintenance processing on the recording head is provided.

[0033] FIG. 5(b) is a diagram showing the arrangement of the nozzle rows when the carriage 501 is viewed from the top surface of the device (-z direction). Five nozzle rows are arranged on the carriage 501 so as to be positioned differently in the X direction. As described above, the nozzle rows are the nozzle row 501C corresponding to cyan ink, the nozzle row 501M corresponding to magenta ink, the nozzle row 501Y corresponding to yellow ink, the nozzle row 501K corresponding to black ink, and the nozzle row 501P corresponding to fluorescent pink ink. C ink is ejected from the nozzles of the nozzle row 501C. M ink is ejected from the nozzles of the nozzle row 501M. Y ink is ejected from the nozzles of the nozzle row 501Y. K ink is ejected from the nozzles of the nozzle row 501K. Fluorescent pink ink is ejected from the nozzle row 501P. In each nozzle row, a plurality of nozzles for ejecting ink as droplets are arranged at a predetermined pitch along the Y direction.

[0034] 5, a carriage 501 carrying the print head 405 is assumed to move in the X direction, but the present invention is not limited to this as long as an image can be printed on a print medium by relative movement. For example, a print head having a nozzle row with a length exceeding the width of the print medium in the X direction may be used to apply ink to a print medium transported in the Y direction to form an image, which is a so-called full multi-printing type print head.

[0035] Here, the fluorescent ink used in this embodiment will be described. In this embodiment, a fluorescent ink is used that is created by mixing a dispersion having fluorescent properties with a solvent and an activator. The fluorescent dispersion used in the fluorescent ink of this embodiment is a dispersion having fluorescent properties. For example, NKW-3207E (fluorescent pink water dispersion: Nippon Kinko Kagaku Co., Ltd.) or NKW-3205E (fluorescent yellow water dispersion: Nippon Kinko Kagaku Co., Ltd.), but any dispersion having fluorescent properties will do.

[0036] The fluorescent dispersion is dispersed in the above-mentioned fluorescent dispersion by combining a known solvent and an activator to produce an ink. The dispersion method of the fluorescent dispersion is not particularly limited. For example, a fluorescent dispersion dispersed by a surfactant, a resin-dispersed fluorescent dispersion dispersed by a dispersion resin, etc. can be used. Of course, it is also possible to use fluorescent dispersions with different dispersion methods in combination. The surfactant can be an anionic, nonionic, cationic, or amphoteric activator. Any resin that is water-soluble or water-dispersible can be used as the dispersion resin, but it is particularly preferable that the weight-average molecular weight of the dispersion resin is 1,000 to 100,000, and more preferably 3,000 to 50,000. The solvent is preferably an aqueous medium containing, for example, water and a water-soluble organic solvent.

[0037] A fluorescent color material is a color material that absorbs light of an excitation wavelength from a ground state to become an excited state, emits light of an emission wavelength, and returns to the ground state to develop color.

[0038] FIG. 10 is a graph showing the intensity of excitation 1001 and the intensity of emission 1002 in an image recorded on a recording medium using fluorescent pink ink. In this graph, the horizontal axis is the wavelength of light, and the vertical axis is the intensity. This graph shows the intensity of light detected when the wavelength of light applied to the recording sample and the wavelength of light received from the recording sample are changed. This figure shows the intensity of light received from the recording sample for each wavelength when the recording sample is irradiated with light of an exciting wavelength.

[0039] Emission 1002 is a graph when 480 nm light is irradiated to a fluorescent pink print sample in this embodiment. Excitation 1001 represents the intensity of received light when the wavelength of the received light is fixed and the wavelength of the light irradiated to the recording sample is changed. FIG. 10 is a graph when the wavelength of the received light is fixed to 600 nm for fluorescent pink in this embodiment. As can be seen from FIG. 10, the wavelength range in which the fluorescent ink recorded on the recording medium is excited overlaps with the wavelength range in which the ink is emitted, and is on the short wavelength side. In addition, excitation 1001 has strengths and weaknesses for each wavelength, and there are wavelengths that emit light efficiently and wavelengths that do not. In addition, since fluorescent coloring materials emit light, the reflectance at the emission wavelength often exceeds 1. In this embodiment, a coloring material having the above characteristics is defined as a fluorescent coloring material.

[0040] Although the above describes the excitation and emission of fluorescent pink, the present invention may use fluorescent inks that emit other wavelengths. For example, fluorescent blue that emits light in the blue region (450 nm to 500 nm) or fluorescent green that emits light in the green region (500 nm to 565 nm) may be used. Fluorescent yellow that emits light in the yellow region (565 nm to 590 nm) may be used. Fluorescent orange or fluorescent red that emits light in the red region (590 nm to 780 nm) may be used. Furthermore, fluorescent inks that are a combination of the above may be used. For example, fluorescent yellow that combines emission in the yellow region and the red region. Furthermore, fluorescent inks with different excitation wavelength intensities may be combined to adjust the color tone. 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.

[0041] In this embodiment, subtractive ink is defined as ink that contains a coloring material that absorbs light of a specific wavelength among irradiated light and does not emit light. In this embodiment, the four colors of cyan, magenta, yellow, and black are subtractive inks. In FIG. 10, 1003 is the spectral reflectance of cyan (C) ink, 1004 is the spectral reflectance of magenta (M) ink, and 1005 is the spectral reflectance of yellow (Y) ink. The graph in FIG. 10 shows the measurement results using a known method for measuring spectral reflectance. Unlike fluorescent ink, subtractive ink only absorbs light, so the reflectance does not exceed 1.

[0042] Next, a case where fluorescent ink and subtractive ink are mixed on a recording medium will be described. When fluorescent pink and yellow are mixed, the yellow absorbs light in the wavelength region of the excitation 1001 of fluorescent pink. Therefore, fluorescent pink cannot be sufficiently excited because the exciting light is absorbed by yellow, and emission is suppressed. When fluorescent pink and cyan 1003 are mixed, the cyan absorbs light in the wavelength region of the emission 1002 of fluorescent pink. Therefore, the cyan ink absorbs the light emitted by fluorescent pink, and emission is suppressed. When fluorescent pink and magenta 1004 are mixed, the fluorescent pink absorbs light in the area where the excitation sensitivity is high, and also absorbs emission. In other words, when fluorescent pink and subtractive ink are mixed on a recording medium, the contribution rate of fluorescent pink to color development is significantly reduced.

[0043] FIG. 11 shows the deflection reflectance characteristics of fluorescent ink and subtractive ink. The solid line shows the deflection reflectance characteristics of fluorescent ink, and the dashed line shows the deflection reflectance characteristics of subtractive ink, which are schematic representations of the bidirectional reflectance distribution function. The deflection reflectance characteristics may be measured by a known method. For example, a method is known in which a sample recorded on a recording medium is irradiated with vertical light and the received reflected light is detected at different angles. As can be seen from this figure, the deflection reflectance characteristics of fluorescent ink scatter light isotropically compared to the deflection reflectance characteristics of subtractive ink. This is because the fluorescent ink absorbs light, excites it, and emits light, eliminating the directionality of the incident light and becoming strongly dependent on the directionality of the emitted light of the fluorescent ink. Therefore, through this experiment, it can be seen that the fluorescent ink scatters light more strongly than the subtractive ink.

[0044] Another characteristic of fluorescent ink is that, compared to subtractive ink, its color changes less with changes in the ambient light spectrum in the visible light range. Typically, subtractive navy blue ink appears to change color depending on the light source. This is because subtractive ink has the property of absorbing specific wavelengths and showing its color by reflecting the remaining components. On the other hand, fluorescent ink has "excitation" and "emission" properties that are different from absorption and reflection. The emission wavelength is in the same wavelength range regardless of the ambient light, so it is less affected by the ambient light spectrum, especially in the visible light range.

[0045] Figure 15 is a graph showing ΔE for each ink color when the ambient light is changed. ΔE is a numerical value that expresses the difference in CIE-Lab when the ambient light is changed. Subtractive inks have a larger color change when the ambient light is changed than fluorescent inks.

[0046] Thus, subtractive ink and fluorescent ink have different characteristics related to color. When an image is recorded using both of these inks, the colors recorded using subtractive inks change in the same way for all inks depending on the light source. On the other hand, colors recorded using fluorescent inks change less depending on the light source. In the process of limiting the amount of ink applied, which will be described later, it is necessary to reduce one of the inks used for recording, but reducing the amount of subtractive ink applied can disrupt the color balance in response to changes in the light source, which may cause the user to perceive a deterioration in image quality.

[0047] Fig. 6 is a block diagram showing the processes executed by each of the design software 102, the RIP software 103, and the printer 104. Figs. 6(a) to (d) show different examples of processing blocks.

[0048] First, Fig. 6(a) will be described. In the design software 102, RGB data 601 and fluorescent pink data 602 are created as image data, and input to the RIP software 103. A user editing the design software 102 specifies and inputs the density of the fluorescent pink ink on the recording medium. The method of specification may be to select a swatch, as explained using Fig. 2, or to set a desired pixel value.

[0049] In the plate making 603 in the RIP software 103, the plate making process described with reference to FIG.

[0050] The CMS 604 in the RIP software 103 performs color management on the RGB data 601. Here, the standard RGB data created by the design software 102 is converted into device RGB data corresponding to the recording device and the type of recording medium on which the image is recorded. This reduces the discrepancy between how the image appears on the display of the PC 101 and how the recorded material appears. Since the size of the color gamut that can be expressed on the display is large compared to the recorded material, various mapping methods can be considered for color management. For example, there is a method of attaching a range that exceeds the representation gamut of the recorded material to the gamut limit of the recorded material, or a method of plotting the entire image so as to be pushed to the center of the gamut. In this embodiment, the input to the CMS 604 is assumed to be the RGB data 601. It is not common to input fluorescent pink data 602 to the CMS 604, but there is no restriction on whether or not to perform CMS on the fluorescent pink data.

[0051] Each process in the printer 104 is carried out by an image processing unit main control unit 411 in FIG.

[0052] In the ink separation 605, the RGB data 601 on which color management has been performed is subjected to ink separation processing. In the ink separation processing, the ink is separated into ink data including elements corresponding to each ink color of the print head 405 based on the RGB color distribution. In this embodiment, 256 gradation data corresponding to four ink colors of cyan, magenta, yellow, and black, excluding fluorescent pink, out of the five ink colors of the print head 405, is generated. Here, the parameters of the ink separation processing are designed so as to be equal to or less than the upper limit of the amount of ink applied per unit area of ​​the print medium on which the image is printed. That is, before the ink separation processing is performed, type information indicating the type of print medium and information regarding the quality and mode of the printing unit 401 are obtained, and the parameters of the ink separation processing are selected based on these. The upper limit of the amount of ink applied in the ink separation processing is determined based on several design guidelines. For example, it is determined so that applying more ink than this value will not cause unevenness on the print medium. Other design guidelines take into consideration that ink ejected on a printed result during continuous printing does not adhere to the printing medium of the next printed result, and that ink on the printing medium does not overflow and adhere to the surface of the print head 405. In Fig. 6(a), fluorescent pink data 602 input from the design software 102 to the RIP software 103 is density data indicating ink density of 256 gradations, and is therefore not subject to processing by the ink separation 605. Note that the number of gradations is not limited to 256 gradations.

[0053] In the gamma conversion 606, the signal values ​​of each ink data in the printer are converted into gradations using a gamma curve. This is for the purpose of linearly associating the change in the signal value output in the ink separation 605 with the density on the recording medium. When one drop of ink is ejected onto the white background of the recording medium, the color changes rapidly from the white. On the other hand, even if one more drop of ink is added to a state in which several drops of ink have already been ejected, the color change is gradual. The gamma conversion 606 applies a gamma curve to the signal value so that the apparent color changes linearly. In this embodiment, the fluorescent pink data 602 input from the design software 102 to the RIP software 103 is also subject to the gamma conversion 606.

[0054] Ink separation 605 and gamma conversion 606 are generally performed using a lookup table, but are not limited to this. For example, a method of conversion using a calculation formula may be used.

[0055] In the application amount limit 607, application amount correction is performed for all ink color data including fluorescent pink data. The purpose is to limit the total amount of ink applied per unit area so that it does not exceed the upper limit that can be accommodated by the recording medium. In this embodiment, for one pixel of the image data of each ink color generated in the ink separation 605, it is determined whether the total value of the application amount exceeds the upper limit value, which is a threshold value, and if it does, the ink amount is reduced so that the total value does not exceed the upper limit value.

[0056] The upper limit that can be accepted by the recording medium used in determining the application amount limit 607 may be the same as the "application amount upper limit" described in the ink decomposition 605, or may be different. In this embodiment, it is assumed to be the same value as the application amount upper limit value set in the parameters used in the ink decomposition 605. In the ink decomposition 605, a boundary value is set as the upper limit as to whether or not unevenness will occur in the image if ink is applied any more than this. On the other hand, the application amount limit 607 may set an upper limit as to a boundary value as to whether or not ink ejected on the printed result during continuous printing will also adhere to the printing medium of the next printed result. Details of the application amount limit 607 will be described separately later.

[0057] In quantization 608, each ink data after gamma conversion is converted into dot data. A printer expresses density on a recording medium by ejecting ink. However, the number of dots that can be ejected in a 600 dpi square area is limited due to various factors such as the nozzle arrangement density of the print head, the specified power, ink filling, and the recording productivity required by the user. In order to express the density expressed by the ink data on a recording medium, quantization 608 distributes dots in each 600 dpi square. By expressing light and dark over a wider range of sizes such as 1200 dpi or 2400 dpi, area gradation is achieved. The dot resolution described here is an example, and the present invention is not limited to this.

[0058] Fig. 6(b) shows a processing block different from that of Fig. 6(a). Here, the difference with respect to Fig. 6(a) will be explained. Ink separation 605 in Fig. 6(b) is assumed to input RGB data 601 and convert it into fluorescent pink data.

[0059] In data synthesis 609, the fluorescent pink data converted in ink separation 605 and the fluorescent pink data 602 input from the RIP software 103, which are of the same color, are synthesized and the synthesis result is output. Data synthesis 609 may be executed before gamma conversion 606, or after application amount limitation 607 and quantization 608. In this block, the two fluorescent pink ink data are synthesized into one data corresponding to the printer head. The synthesis means may be knockout, overprint, or multiplication described in FIG. 3, or other means may be used.

[0060] FIG. 6(c) shows a processing block different from those in FIGS. 6(a) and (b). Here, the differences with respect to FIGS. 6(a) and (b) will be explained. In FIG. 6(c), CMYK data 610 is input from the design software 102. In RGB conversion 611, the input CMYK data 610 is converted to RGB data. The RGB conversion 611 may be integrated with the CMS 604. Note that, although data synthesis 609 is performed in FIG. 6(c), fluorescent pink data may not be generated in ink separation 605 as in FIG. 6(a), and data synthesis 609 may not be performed.

[0061] FIG. 6(d) shows a processing block different from those in FIG. 6(a), (b), and (c). Here, the differences with respect to FIG. 6(a), (b), and (c) will be explained. In FIG. 6(d), each ink data 612 is input from the design software 102. Each ink data is data corresponding to, for example, cyan, magenta, yellow, and black ink. The user specifies and inputs the densities for the other color inks in the same manner as for the fluorescent pink data 602.

[0062] In light and dark separation 613, each ink data except for fluorescent pink is separated into multiple ink data. For example, cyan data is separated into cyan data and light cyan data, and magenta data is separated into light magenta data. Light inks such as light cyan and light magenta are used so that graininess is not visible in the printed matter, so ink data is generated on the printer side, not by the user. Light and dark separation 613 is effective when light ink is included in the inks mounted on the print head 405. If light ink is not used, or if the user creates ink data for light ink using the design software 102, light and dark separation 613 does not need to be performed.

[0063] In each of the use cases in Fig. 6(a) to (d), the application amount limit 607 is executed. In Fig. 6(a) to (c), only the fluorescent pink data does not pass through the ink separation 605. For this reason, if the fluorescent pink data is included in the output result of the ink separation 605, it is expected that the total value of the ink application amount will increase. If the total value of the ink application amount per unit area is greater than the threshold value, ink overflow will occur in the printed matter, and image quality may deteriorate. In Fig. 6(d), the user can freely set the density of all the ink data, so it can be said that there is a higher possibility of ink overflow occurring. The application amount limit 607, which is a characteristic feature of the present invention, is a process for suppressing these problems.

[0064] 7 is a flowchart for explaining a program for determining whether or not an amount of toner has exceeded the limit of toner that is to be provided, which is executed by the toner amount limiting unit 607. The series of processes in FIG.

[0065] In step S701, variables SUM and i are initialized to 0. SUM and i are used later in the flowchart.

[0066] In step S702, loop processing is performed. i functions as a loop counter, and is initialized to 0 in step S701. COL_NUM corresponds to the number of ink colors equipped in the print head 405. For example, if the ink ejected from the print head 405 is five colors, cyan, magenta, yellow, black, and fluorescent pink, COL_NUM is 5. Loop counter i performs loop processing (COL_NUM-1) times. If loop counter i is equal to or less than COL_NUM, the process proceeds to step S703.

[0067] In step S703, the application amount of the ink color having the ink ID corresponding to the loop counter i is added to SUM.

[0068] In step S704, the loop counter i is counted up, and the process loops from step S703 to step S704 a number of times equal to (COL_NUM-1).

[0069] In step S705, a determination process is performed using SUM and the threshold value TH for determining excess application amount. The threshold value TH is associated with the upper limit that the recording medium can accept. For example, if there is a risk of ink overflowing from the recording medium and causing a machine failure when the ink application amount exceeds 1000 in a glossy recording medium, then TH = 1000 is set. TH can be set to different values according to the type of recording medium. Also, depending on the recording quality that the user can select, the number of scans of the recording head 405 for a designated area of the recording medium changes. Since the landing timing changes due to the difference in the number of scans, the upper limit that the recording medium can accept also changes, so different values can be set not only according to the type of recording medium but also according to the recording quality. TH is stored in the ROM or RAM provided in the image processing unit main control unit 411 and is acquired based on at least one of the type information of the recording medium and the quality information indicating the recording quality. Incidentally, when executing the flow of FIG. 7, the threshold value may be externally set through the operation unit 414, or it may be in a form where the threshold value is acquired from RIP software or an external HDD through the external connection I / F 416. If the determination process result is YES (SUM ≧ TH), it transitions to step S706, and if NO (SUM < TH), it transitions to step S707.

[0070] In step S706, when transitioning to this step, since the total ink application amount exceeds the upper limit that the recording medium can accept, it transitions to the application amount limit processing flowchart.

[0071] In step S707, when transitioning to this step, since the total ink application amount is within the upper limit that can be accepted per pixel of the recording medium, it does not transition to the application amount limit processing flowchart and ends the application amount limit 607.

[0072] Incidentally, the series of processing flows in FIG. 7 are performed for each pixel for all pixels. That is, in this embodiment, based on the CMYK values and P value of each pixel, the total ink application amount per pixel is compared with the threshold value.

[0073] FIG. 8 shows the ink ID, ink name, and application amount for a certain pixel value. In the example of FIG. 8, the ink ID is set from 0 to 4, cyan ink corresponds to ink ID=0, and the application amount of cyan ink for a certain pixel is set to 250. The ink IDs in step S703 of FIG. 7 correspond to ink IDs=0 to 4 in FIG. 8. It is assumed that the application amount differs depending on the pixel. In the example of FIG. 8, the total SUM of the application amounts is 1015. When TH=1000, SUM≧TH, so a transition is made to application amount limiting processing.

[0074] 9 is a flowchart for explaining a program for the grant amount limiting process executed by the grant amount limiting 607. The series of processes in FIG.

[0075] In step S901, a variable OVR is used. OVR is calculated using SUM and TH used in Fig. 7. Here, the value of SUM reflects the result of sequential addition in step S703 in the flowchart of Fig. 7. OVR represents the amount by which the total amount of ink applied to the pixel of interest exceeds the upper limit that the print medium can accept.

[0076] In step S902, loop processing is performed. i functions as a loop counter, and is initialized to 0 in step S701. COL_NUM corresponds to the number of ink colors equipped in the print head 405. For example, if the print head 405 is compatible with cyan, magenta, yellow, black, and fluorescent pink inks, COL_NUM is 5. Loop counter i performs loop processing a number of times equal to (COL_NUM-1). If loop counter i is equal to or less than COL_NUM, the process proceeds to step S903.

[0077] In step S903, it is determined whether the ink ID corresponding to the loop counter i is a fluorescent color. As shown in Fig. 8, in this embodiment, the ink ID = 4 is a fluorescent color. If the ink ID corresponding to the loop counter i indicates a fluorescent ink, the process proceeds to step S904, and if it indicates a non-fluorescent ink, the process proceeds to step S909.

[0078] In step S904, the amount of ink applied to the pixel of interest, which is the ink ID corresponding to loop counter i, is compared with OVR. If OVR is smaller, the process proceeds to step S905, and if not, the process proceeds to step S907.

[0079] In step S905, OVR is subtracted from the amount of ink applied to the pixel of interest, the ink ID of which corresponds to loop counter i, to correct the amount of ink applied. In step S906, the value of OVR is updated to 0. In steps S905 and S906, OVR, which is the amount that exceeds the threshold, is used to subtract the amount of fluorescent ink applied.

[0080] In step S907, the application amount of the ink having the ink ID corresponding to the loop counter i is corrected to zero.

[0081] In step S908, the amount of ink applied, which is the ink ID corresponding to the loop counter i, is subtracted from the value of OVR to update the value of OVR.

[0082] In steps S907 and S908, the excess amount, OVR, is used to set the amount of fluorescent ink applied to 0. If multiple fluorescent colors are included in the number of colors defined by COL_NUM, the fluorescent colors are corrected to 0 one by one until the number falls within the upper limit, TH. According to this flowchart, the multiple fluorescent ink colors are subject to the subtraction process in ascending order of ink ID number.

[0083] In step S909, the loop counter i is counted up by (COL_NUM-1), and the process loops from step S903 to step S904.

[0084] By executing the above flow, the amount of applied fluorescent ink is changed in response to the excess over the upper limit of the amount of applied ink, so that the total amount of applied ink is adjusted to be equal to or less than the upper limit of the amount of applied ink. As shown in Figures 6(a) to (d), even if the user directly specifies the amount of applied fluorescent pink, the total amount of applied ink and the upper limit that the recording medium can accept are referenced, and degradation of image quality due to ink overflowing onto the recording medium can be suppressed.

[0085] In this embodiment, only the fluorescent pink ink is corrected so as not to exceed the upper limit, and the amount of fluorescent ink subtracted is the largest among the five colors of ink provided in the print head 405. An example in which subtractive color ink is also subtracted will be described in the third embodiment described later.

[0086] Second embodiment In the first embodiment described above, the calculation is performed by adding the application amount of each ink for the number of colors defined by COL_NUM to SUM, as shown in the flowchart in Fig. 7. With this implementation method, there is a concern that the processing load will increase as the number of ink colors increases.

[0087] In this embodiment, a method for reducing the processing load required for calculating SUM will be described. Specifically, when the ink separation 605 converts RGB data or CMYK data into data corresponding to the number of ink colors equipped in the print head 405, a total value of the application amount of all the converted ink colors is generated.

[0088] Fig. 12 is an example of a lookup table used in the conversion of ink separation 605. Assuming Fig. 6(A), the input to ink separation 605 is for the three colors RGB. When ink separation 605 is performed, the application amounts of each of cyan, magenta, yellow, and black ink are output, and at this time, a SUM, which is the total application amount of the output results, is also output. For example, if the output values ​​are (cyan, magenta, yellow, black) = (220, 220, 250, 100), a value of SUM = 790 is output. At the time of outputting ink separation 605, the application amount of fluorescent pink has not been added to SUM.

[0089] Fig. 13 is a flowchart of the grant amount limiting process performed by the grant amount limit 607 in this embodiment. In this embodiment, the excess determination and limiting process are expressed in one flowchart. The series of processes in Fig. 13 are performed by the CPU of the image processing unit main control unit 411. Here, the differences from Fig. 9 will be described.

[0090] In step S1301, the fluorescent color ink ID is obtained and stored in the variable fp.

[0091] In step S1302, the variable OVR is used to calculate the excess amount of ink applied relative to the upper limit acceptable for one pixel on the recording medium. The calculation formula is SUM converted using the lookup table in Fig. 12, and the amount of fluorescent ink applied corresponding to ink ID = fp is added to calculate the total amount of all inks applied. Then, TH is subtracted from the calculated total value of all inks to calculate the excess amount.

[0092] If there are two or more ink colors among the ink colors provided in the print head 405 that were not added in the calculation of the SUM in the ink separation 605, the ink application amounts to be added in step S1302 are increased to two or more.

[0093] By executing the above flow, the number of additions required to calculate SUM can be reduced compared to the first embodiment, and the load on the calculation process can be reduced.

[0094] Since a lookup table is used, an error occurs in the values ​​between the grid points of the lookup table. It is also possible to set the SUM value converted in ink separation 605 to the total value of the results of gamma conversion 606 of the application amount of each ink. In that case, the conversion error caused by the lookup table will be larger.

[0095] The reason for the large conversion error is that the lookup table cannot fully reproduce the curve shape of the gamma curve. Also, the gamma curve has a different shape for each ink color. To reduce the conversion error, the conversion result of SUM should be modulated using as a reference the signal value of at least one ink that has the largest change in output Y relative to the change in input X for the gamma curve of each ink color.

[0096] For example, if the gamma curve for black changes most steeply among cyan, magenta, yellow, and black, SUM can reduce the error by performing gamma conversion 606 using a gamma curve based on the amount of change in the gamma curve for black.

[0097] 6B and 6C, when the fluorescent pink data is converted by the ink separation 605, the SUM is converted using a lookup table such as that shown in Fig. 14. The fluorescent pink data converted by the ink separation 605 is not added to the conversion result of the SUM.

[0098] (Third embodiment) In the first and second embodiments, if the total amount of ink applied to the pixel of interest exceeds the upper limit that can be accepted per pixel on the recording medium, the amount of subtractive ink applied, which is the base color, is not changed, and the amount of fluorescent ink applied is corrected. This is because, as mentioned above, fluorescent ink changes color little in the visible light region due to changes in environmental light.

[0099] On the other hand, if the amount exceeds the upper limit by a large amount, the amount of fluorescent ink applied may become zero. If it is desired to retain the fluorescent feel in the recorded image, it is effective to reduce the ink application amount, mainly of the fluorescent ink, within a range that maintains the fluorescent feel of the fluorescent ink, while reducing the subtractive ink. The ratio at which the amount of fluorescent ink applied is reduced relative to the amount of subtractive ink applied can be controlled, for example, as follows:

[0100] <Method 1. Subtraction by a specified ratio> The excess amount OVR value is divided in a ratio of 7:3, and 70% of the excess amount is used for subtraction from the fluorescent ink, and 30% is used for subtraction from the subtractive ink. In the subtraction process, the amount of fluorescent ink subtracted is set to be greater than the amount of subtractive ink subtracted. For subtractive ink, all colors may be subtracted equally, or lower brightness inks that are less likely to cause visible color changes may be subtracted more. For example, the apparent color change can be minimized by setting the subtraction rate to be greater the higher the brightness of the ink dot on the paper.

[0101] Furthermore, when subtracting subtractive inks, the subtraction ratio assigned to each ink color may be varied for each pixel. By varying the subtraction ratio for each pixel, it is possible to continue to maintain the fluorescent ink.

[0102] Alternatively, the subtraction ratio may be preset for each hue. Alternatively, the subtraction ratio corresponding to the pixel values ​​of CMYK before subtraction may be stored in the ROM of the image processing unit main control unit 411 and read out when the subtraction process is executed.

[0103] <Method 2. Subtraction based on threshold> The maximum value by which fluorescent ink can be subtracted from the excess amount OVR is set as the threshold value THf. In other words, the amount of fluorescent ink to be subtracted is THf, and the amount of subtractive ink to be subtracted is calculated as OVR-THf. The set value of THf can be set so that the amount of fluorescent ink to be subtracted is greater than the amount of each subtractive ink to be subtracted. The threshold value THf may also be varied according to the density of the fluorescent ink for each pixel. By varying it for each pixel, it is possible to continue to retain the fluorescent ink.

[0104] Thus, in this embodiment, when the total amount of applied ink exceeds the upper limit, the amount of applied fluorescent ink is reduced the most, but the amount of applied fluorescent ink is made greater than 0. At the same time, the amount of applied subtractive ink is reduced to a degree that has little effect on the color of the recorded image. This makes it possible to prevent ink overflow while maintaining the contribution of the fluorescent ink to the recorded image.

[0105] (Other embodiments) In the above-described embodiment, the excess amount of the applied ink relative to the upper limit that can be accepted by the print medium is calculated in the flow charts of Fig. 9 and Fig. 13. The means for calculating the excess amount is not limited to the above. For example, when a lookup table is used by the ink decomposition 605, it is possible to calculate the excess amount OVR by performing a calculation including fluorescent pink data in the input to the lookup table.

[0106] Also, if it is possible to increase the input information of the lookup table, it is also possible to convert the "fluorescent pink data resulting from subtracting the excess amount" using the lookup table.

[0107] In the above embodiment, fluorescent ink is used as the ink of the specific color, but the determination process and correction process for fluorescent ink can also be applied to inks other than fluorescent ink.

[0108] For example, as shown in FIG. 15, unlike subtractive ink, metallic ink containing metal particles has no absorbing components. Therefore, it has a property of being less susceptible to the influence of ambient light than subtractive ink. Compared to subtractive ink and fluorescent ink containing color components, ΔE, which indicates the color change when the amount of application is reduced, is small. Therefore, when reducing the amount of application, it is preferable to prioritize metallic ink over subtractive ink. This makes it possible to suppress the deterioration of image quality due to overflow of ink while suppressing the variation in color in the recorded image. Metal particles are typified by silver, but are not limited thereto. Particles of gold, silver, copper, platinum, aluminum, titanium, chromium, iron, nickel, zinc, zirconium, tin, etc. may also be used. These metal particles may be used alone or in alloys, and can also be used in combination, but it is preferable to use gold, silver, and copper particles in view of the storage stability of the metal particles.

[0109] In the above embodiment, the process in the application amount limit 607 is performed based on a color signal including the five ink color elements (C, M, Y, K, P), but it is also possible to obtain the excess amount from the color signal (R, G, B, P). In this case, it is sufficient to store in advance the excess amount corresponding to the combination of the values ​​of each element (R, G, B, P). This can be realized by using a lookup table that outputs the excess amount for the input of (R, G, B, P), and the more lattice points the lookup table has, the more the accuracy can be improved. Note that the process of preferentially reducing the application amount of ink of a specific color based on the excess amount can be performed in the same manner as in the above embodiment.

[0110] In the above embodiment, subtractive inks of four colors, C, M, Y, and K, are used as the basic color inks, but the number of ink colors is not limited.

[0111] In the above embodiment, an example has been described in which each processing flow is executed by the CPU of the image processing unit main control unit 411, but a configuration in which part of the processing is executed by the CPU of the recording unit main control unit 403 may also be adopted. Also, a configuration in which a program for each processing flow is read from a storage medium in which it is stored and executed by a computer may also be adopted. [Explanation of symbols]

[0112] 101 PC 104 Printer 403 Recording unit main control unit 405 Recording Head 411 Image processing unit main control unit 501 Carriage

Claims

1. an acquisition means for acquiring a color signal including a plurality of elements indicating the amount of each of the inks of the plurality of colors applied, for recording an image by applying inks of a plurality of colors, the inks including at least one basic color ink and a fluorescent ink including a dispersion having a fluorescent property, onto a recording medium; a determination means for determining whether a total value of a plurality of elements included in the color signal is greater than a threshold value; a reduction means for reducing a value of at least one of a plurality of elements included in the color signal when it is determined that the sum is greater than the threshold value, so that the reduced sum is smaller than the unreduced sum; Equipped with 4. An image processing apparatus comprising: an image processing unit that performs a reduction process by said reducing means, the amount by which the value of the element corresponding to said fluorescent ink is reduced the most among a plurality of elements contained in said color signal.

2. 2. The image processing apparatus according to claim 1, wherein said reducing means does not reduce values ​​of elements corresponding to inks of basic colors.

3. 3. The image processing apparatus according to claim 1, wherein the determining unit sets the threshold value based on at least one of type information indicating a type of recording medium on which the image is recorded and quality information indicating a recording quality of the image.

4. 4. The image processing apparatus according to claim 1, wherein the ink of each of the basic colors is ink that contains a color material that absorbs light of a specific wavelength and does not emit light.

5. 5. The image processing apparatus according to claim 1, wherein the inks of the plurality of colors include cyan ink, magenta ink, and yellow ink as basic color inks.

6. 6. The image processing device according to claim 1, wherein the acquiring means acquires a color signal including an element indicating an amount of ink of at least one basic color applied, and a color signal including an element indicating an amount of the fluorescent ink applied.

7. 7. The image processing device according to claim 6, further comprising a color separation means for generating a color signal including an element indicating an amount of application of ink of at least one basic color and not including an element indicating an amount of application of the fluorescent ink, and inputting the generated color signal to the acquisition means.

8. 8. The image processing apparatus according to claim 7, wherein a total value of elements contained in the color signals generated by said color separation means is equal to or smaller than a threshold value.

9. 9. The image processing apparatus according to claim 7, wherein the determining means calculates the sum of an element included in the color signal generated by the color separation means and an element of the fluorescent ink as the total value.

10. 6. The image processing apparatus according to claim 5, wherein the inks of the plurality of colors further include black ink.

11. 6. The image processing apparatus according to claim 5, wherein the inks of the plurality of colors further include at least one of a light cyan ink and a light magenta ink.

12. the acquiring means acquires a color signal for each pixel corresponding to a unit area on a recording medium; 12. The image processing apparatus according to claim 1, wherein the determination process by the determination means and the reduction process by the reduction means are performed for each acquired pixel.

13. the plurality of colors of ink further includes a second fluorescent ink having a different color from the fluorescent ink; 13. An image processing device according to claim 1, wherein in the reduction process by the reduction means, the amount by which the value of the element corresponding to the second fluorescent ink is reduced is greater than the amount by which the value of the element corresponding to the basic color ink is reduced.

14. 14. The image processing apparatus according to claim 1, further comprising a recording unit for applying the inks of the plurality of colors onto a recording medium.

15. an acquisition step of acquiring a color signal including a plurality of elements indicating the amount of each of the inks of the plurality of colors applied, for recording an image by applying inks of a plurality of colors, the plurality of colors including at least one basic color ink and a fluorescent ink containing a dispersion having a fluorescent property, onto a recording medium; a determination step of determining whether a total value of a plurality of elements included in the color signal is greater than a threshold value; a reduction step of reducing a value of at least one element among a plurality of elements included in the color signal such that the reduced total value is smaller than the total value before the reduction when the total value is determined to be greater than the threshold value; Equipped with an amount of reduction in the value of the element corresponding to the fluorescent ink among a plurality of elements contained in the color signal, the amount of reduction being the largest in the reduction process of the reduction step;

16. A program for causing a computer to execute each step of the image processing method according to claim 15.

17. an acquisition means for acquiring a color signal including a plurality of elements indicating the amount of each of the inks of the plurality of colors applied, for recording an image by applying inks of a plurality of colors, the inks including at least one basic color ink and a fluorescent ink including a dispersion having a fluorescent property, onto a recording medium; a determination means for determining whether a total value of a plurality of elements included in the color signal is greater than a threshold value; a reduction means for reducing a value of at least one of a plurality of elements included in the color signal when it is determined that the sum is greater than the threshold value, so that the reduced sum is smaller than the unreduced sum; Equipped with The image processing device according to claim 1, wherein the reducing means preferentially reduces the value of an element corresponding to the fluorescent ink among a plurality of elements included in the color signal.

Images