JP2019186851A - Control apparatus, color material amount restriction method, and color material amount restriction program - Google Patents

Abstract

To suppress deterioration of a color reproduction even if a color material amount is restricted when printing a matter by using a color material of a color and while color.SOLUTION: A control apparatus that controls a print device is provided with a color material restriction processing part that reduces a color material amount so that a total value of the color material amount of a color in a prescribed pixel and the color material amount of a white color becomes a color material amount restriction value or less in a control apparatus that controls a print device, and changes a ratio of a reduction amount of the color material amount of the color and the reduction amount of the color material amount of the white color in accordance with color information of image information. The color material amount restriction processing part acquires a hue value corresponding to a device value, determines a distribution ratio of the color material reduction amount corresponding to the color and the white color on the basis of the hue value, and provides a distribution ratio determination part for registering the device value and the distribution ratio so as to be corresponded. The color material amount restriction processing part calculates the color material reduction amount by subtracting the color material amount restriction value from the total value of a pixel value of an input pixel of the color and the pixel value of a ground of the white color, acquires the distribution ratio of the device value corresponding to the pixel value of the input pixel, and distributes the color material reduction amount into the input pixel and the ground on the basis of the distribution ratio.SELECTED DRAWING: Figure 13

Description

  The present invention relates to a control device, a color material amount restriction method, and a color material amount restriction program, and in particular, a control device that controls a printing device that performs printing by adding a white background to a color input image, and a color at the time of printing. The present invention relates to a color material amount restriction method for controlling material amount restriction and a color material amount restriction program that operates in the control device.

  When printing an input image consisting of colored components of C (Cyan), M (Magenta), Y (Yellow), K (Key Plate) on a transparent substrate or a colored opaque substrate, Since the apparent color of the input image changes under the influence of the background color of the opaque base material, a method of providing a W (White) background (hereinafter abbreviated as white background) is used. In general, when using a transparent substrate, the white background is printed on the uppermost layer in order to observe the input image from the transparent substrate side, and when using an opaque substrate, the white background is printed on the lowermost layer. .

  Thus, when printing a white background and an input image on a transparent substrate or an opaque substrate, it takes time to print if the white background and the input image are printed separately. A highly productive on-demand printer capable of printing a total of five colors at once is desired. In this printing, in the case of an electrophotographic system, there is a limit to the amount of color material (toner amount) that can be transferred and fixed at a time, and this is expressed as a color material amount limit value (generally the sum of pixel values [%] for each color). ) Is determined, color material amount restriction processing is performed in the printing system so that the sum of the pixel values of the white background and the input image does not exceed the color material amount restriction value.

  Regarding the technology for printing such a white background and an input image in an overlapping manner, for example, Patent Document 1 listed below includes a first image forming unit that forms a white toner image on a transparent recording medium using white toner, A second image forming means for forming on the transparent recording medium a superposed toner image in which the toner images of the respective colors are overlapped with each other using a plurality of color toners, and a white toner image and a superposed toner image formed on the transparent recording medium Fixing means for fixing the toner image to the transparent recording medium at least by heat, and an image forming apparatus for forming a white toner image on the overlapping toner image formed on the transparent recording medium. A control means for controlling the first image forming means so as to change the toner adhesion amount of the white toner image formed on the superimposed toner image according to the toner adhesion amount. Configuration is disclosed having.

Japanese Patent Laying-Open No. 2015-064401

  When an input image including a white background is printed, in order to ensure color reproducibility of the input image, it is ideal that the color material amount limit value is CMYK color material amount + 100%. However, the color material amount limit value of a normal printing device is 400% or less, and in order to increase this color material amount limit value, it is necessary to greatly improve the transfer capability and fixing capability of the printing device, and the color material itself. It is difficult to realize.

  Therefore, it is necessary to reduce the color material amount so that the color reproduction does not deteriorate even with a smaller color material amount limit value. However, if the color material amount limit value is less than 300%, an input pixel represented by the above-mentioned Patent Document 1 is used. When the method of reducing the white pixel value according to the total color pixel value is used, the white pixel value is greatly reduced and the color reproduction is greatly deteriorated. In particular, when an input image is printed on an opaque base material such as colored paper, the paper color directly affects the background color, so that the color reproduction deteriorates significantly.

  The present invention has been made in view of the above-described problems, and its main purpose is that when the amount of color material is limited when printing with a white background added to a color input image. Another object of the present invention is to provide a control device, a color material amount limiting method, and a color material amount limiting program capable of suppressing deterioration in color reproduction.

  One aspect of the present invention is a control device that controls a printing apparatus that performs printing using a color material and a white color material based on image information, the color material amount and white color in a predetermined pixel The color material amount is reduced so that a total value with the color material amount is equal to or less than a predetermined color material amount limit value, and a color material amount restriction processing unit that instructs the printing apparatus to perform printing is provided. The material amount restriction processing unit changes a reduction ratio between the color material amount reduction amount and the white color material amount reduction amount according to the color information of the image information.

  One aspect of the present invention is a color material amount limiting method in a printing system including a printing apparatus that performs printing using a color color material and a white color material based on image information. A color material amount restriction process for instructing printing to the printing apparatus by reducing the color material amount so that the total value of the color material amount and the white color material amount is equal to or less than a predetermined color material amount restriction value. And executing the color material amount restriction process to change the reduction ratio between the color material amount reduction amount and the white color material amount reduction amount according to the color information of the image information. To do.

  One aspect of the present invention is a color material amount restriction program that operates on a control device that controls a printing device that performs printing using a color material and a white color material based on image information, the control Reduce the color material amount so that the total value of the color color material amount and the white color material amount in a predetermined pixel is equal to or less than a predetermined color material amount limit value, and print on the printing apparatus. The instructed color material amount restriction process is executed, and in the color material amount restriction process, the color material amount reduction amount and the white color material amount reduction amount are reduced according to the color information of the image information. It is characterized by changing the ratio.

  According to the control device, the color material amount restriction method, and the color material amount restriction program of the present invention, even when the color material amount is restricted when performing printing with a white background added to a color input image. It is possible to suppress the deterioration of color reproduction.

  The reason is that the control device that controls the printing device sets the color material amount so that the total value of the color material amount and the white color material amount in a predetermined pixel is equal to or less than a predetermined color material amount limit value. A color material amount restriction processing unit for instructing the printing apparatus to perform printing is provided, and the color material amount restriction processing unit determines whether the color material amount reduction amount and the white color material correspond to the color information of the image information. This is because the ratio of reduction to the amount of reduction is changed. Furthermore, the color value corresponding to the selected device value is obtained, and based on the color value, the distribution ratio that defines the reduction ratio of the color material amount for the color and white is determined, and the device value and the distribution ratio are supported. In addition, a distribution ratio determining unit to be registered in the list is provided, and the color material amount restriction processing unit subtracts the color material amount restriction value from the total value of the pixel value of each color input pixel and the pixel value of the white background. The color material reduction amount is calculated, the distribution ratio associated with the device value corresponding to the pixel value of each input pixel is obtained by referring to the list, and the color material reduction amount is determined as the input pixel based on the distribution ratio. This is because the amount of the color material and the white color material is limited by being distributed to the base.

It is a schematic diagram which shows the maximum pixel value in the case of printing 4 colors of CMYK on an opaque base material. It is a schematic diagram which shows the maximum pixel value in the case of printing WCMYK 5 colors on an opaque base material. It is a schematic diagram explaining a conventional color material reduction method (a method of reducing a white pixel value in accordance with a total color pixel value of input pixels). It is a schematic diagram explaining the color material reduction method (method to change the distribution ratio of the color material reduction amount to white) of the present invention. It is a schematic diagram explaining the color material amount restriction | limiting process which concerns on one embodiment of this invention. It is a schematic diagram explaining the range of the brightness which defines the distribution ratio to the white of the color material reduction amount which concerns on one embodiment of this invention. 1 is a schematic diagram illustrating an example of a configuration of a printing system according to an embodiment of the present invention. It is a schematic diagram which shows the other example of a structure of the printing system which concerns on one Example of this invention. It is a block diagram which shows the structure of the client terminal which concerns on one Example of this invention. It is a block diagram which shows the structure of the controller which concerns on one Example of this invention. 1 is a block diagram illustrating a configuration of a printer according to an embodiment of the present invention. It is a flowchart figure which shows the process (distribution ratio determination process of the coloring material reduction amount) of the controller which concerns on one Example of this invention. It is a flowchart figure which shows the process (Color material amount restriction | limiting process with respect to an input image) of the controller which concerns on one Example of this invention. It is a schematic diagram explaining the range of the brightness which defines the distribution ratio to the white of the color material reduction amount which concerns on one embodiment of this invention. It is a schematic diagram explaining the range of the ratio of the brightness which defines the distribution ratio to the white of the color material reduction amount which concerns on one embodiment of this invention. It is a schematic diagram explaining the range of the saturation which defines the distribution ratio to the white of the color material reduction amount which concerns on one embodiment of this invention. It is a schematic diagram explaining the range of the ratio of the saturation which defines the distribution ratio to the white of the color material reduction amount which concerns on one embodiment of this invention.

  As shown in the background art, when printing a total of 5 colors of WMY on the white background + CMYK of the input image at once, there is a limit to the amount of color material (toner amount) that can be transferred and fixed at once in the electrophotographic system. Yes, because the color material amount limit value is determined, the total of the input image and the white background pixel value exceeds the color material amount limit value in the RIP (Raster Image Processor), profile creation unit, print engine, etc. in the printing system. Color material amount restriction processing is performed so as not to exist.

  Regarding this color material amount restriction process, the color material amount restriction value is determined in consideration of the transfer ability and fixing ability of the printing apparatus. For example, when an input image is printed on a non-transparent substrate such as paper using a CMYK color material (toner), the maximum pixel value on the input data is 400% as shown in FIG. As shown in FIG. 1B, the maximum pixel value on the input data after the color material amount limitation is less than 400%, and toner of each color is reduced. In this case, the amount of toner reduction may be the same or different for each color of CMY, and CMY may be replaced with K. Further, the specific amount (such as weight) of “100%” may be different for each color.

  In addition, as shown in FIG. 2 (a), when printing a background of W in addition to a CMYK input image on an opaque base material such as paper (particularly colored paper) (in the case of an opaque base material, W is usually the highest). Lower layer), the maximum pixel value on the input data is 500%, but the color material amount limit value does not change unless the transfer capability, fixing capability, and toner of the printing apparatus are improved, as shown in FIG. In addition, the maximum pixel value on the input data is less than 400%, and the amount of toner distributed to CMYK is further reduced by adding W. Similarly, when printing a W substrate on a transparent substrate such as plastic film in addition to the CMYK input image (usually W is the top layer for transparent substrates), the maximum pixel on the input data is the same. The value is less than 400%, and the amount of toner distributed to CMYK is further reduced by adding W.

  Here, Patent Document 1 proposes a method of reducing only the white pixel value according to the sum of the color pixel values of the input pixels (restricting to the necessary adhesion amount). However, only the white pixel value or the white pixel is proposed. In the method of preferentially reducing the value, the white pixel value is greatly reduced, so that the color reproduction deterioration, particularly the visual evaluation deterioration width, increases. Specifically, as shown in FIG. 3, when the white pixel value is greatly reduced with respect to an input pixel having high brightness or high saturation (particularly high brightness) (a point where the reduction amount of the black circle in the figure is 0), the brightness or saturation is reduced. Since (especially brightness) falls significantly, the influence on visual evaluation becomes large. In addition, when printing an input image on a transparent substrate, the influence of the background color can be reduced by placing the transparent substrate away from the background, but the input image is printed on an opaque substrate such as colored paper. In the case of printing, the paper color directly affects the background color, and thus the visual evaluation is significantly affected.

  In response to this problem, the inventors of the present application verified the color reproduction when the color material reduction amount is distributed to the color and the white at various ratios with respect to the input pixels of various colors, as shown in FIG. In this way, for input pixels with high brightness and high saturation (especially high brightness), the distribution ratio of the color material reduction amount to white is larger (the circle hatched with the dots in the figure) than the color material reduction amount to white. It has been found that a smaller color distribution ratio (white circles in the figure) provides better color reproduction.

  Therefore, in one embodiment of the present invention, when an image is formed using color (CMYK) and white (background) color materials based on this knowledge, the output pixel value is relative to the total input pixel value. When limiting the amount of color material so that it is less than or equal to the specified limit value, the amount of color material reduced (the total of input pixel values and the amount of color material) based on the color values (lightness and saturation) of the color components of the input pixel The distribution ratio of white / color of the difference in limit values) is determined. Specifically, the control device that controls the printing apparatus allows the color material amount so that the total value of the color color material amount and the white color material amount in a predetermined pixel is equal to or less than a predetermined color material amount limit value. The color material amount restriction processing unit for instructing the printing apparatus to perform printing is provided, and the color material amount restriction processing unit determines the color material amount reduction amount and the white color according to the color information of the image information. Change the ratio of reduction with the amount of material reduction. Furthermore, the color value corresponding to the selected device value is obtained, and based on the color value, the distribution ratio that defines the reduction ratio of the color material amount for the color and white is determined, and the device value and the distribution ratio are supported. In addition, a distribution ratio determining unit to be registered in the list is provided, and the color material amount restriction processing unit subtracts the color material amount restriction value from the total value of the pixel value of each color input pixel and the pixel value of the white background. The color material reduction amount is calculated, the distribution ratio associated with the device value corresponding to the pixel value of each input pixel is obtained by referring to the list, and the color material reduction amount is determined as the input pixel based on the distribution ratio. Distribute to the ground to limit the amount of color and white color material. As a result, even when the amount of color material is limited (especially when the amount of color material is limited under less than 300%), the amount of both color and white is reduced with an optimal balance (color material). The amount of reduction can be distributed), and color development can be improved by suppressing deterioration of color reproduction.

  The color material amount restriction process of the present embodiment described above will be outlined with reference to the schematic diagram of FIG. When forming an image with five colors of white and CMYK on an opaque base material such as colored paper, first, as shown in FIG. 5A, using a printer profile, the color value is obtained from the CMYK value of the input pixel, Based on the acquired color values (lightness, saturation), the distribution ratio of the color material reduction amount to white / color is determined and stored according to a predetermined rule.

  For example, when the lightness is used as the color value, as shown in FIG. 6, the distribution ratio of the color material reduction amount to white decreases as the input pixel becomes lighter (L * increases) (white pixel). Value). The details of the method for determining the distribution ratio of the color material reduction amount based on the color value will be described later, but the range of the color value (in this case, the brightness) that defines the region where the distribution ratio to white decreases as the brightness increases. Define.

  Next, color material amount restriction processing is performed according to the determined distribution ratio. Specifically, as shown in FIG. 5B, the color material reduction amount is calculated from the sum of the white + CMYK pixel values and the color material amount limit value, and the calculated color material reduction amount and the stored color material reduction amount are calculated. The white reduction amount and the color (CMYK) reduction amount are calculated from the white / color distribution ratio. Then, as shown in FIG. 5C, the color material amount of each of white / color (CMYK) is reduced, and the output pixel shown in FIG. 5D is generated. The white / color (CMYK) color material amount limiting process can use an existing method.

  As described above, the color reproduction deterioration can be suppressed by allocating the color material reduction amount to white / color according to the color value (lightness, saturation) of the input pixel. In particular, colors with a large deterioration width in visual evaluation (high brightness colors that greatly reduce the brightness by reducing the white pixel value) and opaque substrates such as colored paper (paper color Advantageous color reproduction can be achieved when printing on a substrate that directly affects the background color.

  In order to describe the above-described embodiment of the present invention in more detail, a control device, a color material amount limiting method, and a color material amount limiting program according to an embodiment of the present invention will be described with reference to FIGS. explain. 7 and 8 are schematic views showing the configuration of the printing system of this embodiment, and FIGS. 9 to 11 are block diagrams showing the configurations of the client terminal, the controller, and the printer, respectively. FIGS. 12 and 13 are flowcharts showing the processing of the controller of this embodiment, and FIGS. 14 to 17 explain the range of color values that define the distribution ratio of the color material reduction amount to white. It is a schematic diagram.

  In the following description, the coloring component is, for example, CMYK and does not include white. The color component is, for example, CMY, and does not include white (W) that does not transmit light or black (K) that does not transmit or reflect light. The pixel values of these coloring components and color components are multivalued such as% and 8 bits. This% corresponds to, for example, a pixel value 0-255 of 8-bit input data, 0% corresponds to a pixel value 0, 50% corresponds to a pixel value 127, and 100% corresponds to a pixel value 255. The primary color solid is a color having the maximum pixel value of one color in CMY, such as C100%, M100%, and Y100%. The secondary color solid is R = M100% + Y100%, G = C100% + Y100%, B = C100% + M100%, and so on, which are the colors in which the pixel values of the two colors of CMY are maximized.

  As shown in FIG. 7, in the printing system of this embodiment, a client terminal 10, a controller 20, and a printer 30 that can be connected via a communication network 40 are arranged on an intranet. Ethernet (registered trademark) or the like can be used as the standard of the communication network 40, but it is also possible to use IEEE1394, Parallel, or the like other than Ethernet (registered trademark) for data transfer from the controller 20 to the printer 30.

  In FIG. 7, the controller 20 and the printer 30 are separate devices, but the printer 30 may include the controller 20 as shown in FIG. 8. Hereinafter, each device will be described in detail on the assumption of the configuration of FIG.

[Client terminal]
The client terminal 10 is a computer device such as a personal computer, and creates a print job and transmits it to the controller 20. As shown in FIG. 9A, the client terminal 10 includes a control unit 11, a storage unit 12, a network I / F unit 13, a display unit 14, an operation unit 15, and the like.

  The control unit 11 includes a CPU (Central Processing Unit) 11a and a memory such as a ROM (Read Only Memory) 11b and a RAM (Random Access Memory) 11c. The CPU 11a stores a control program stored in the ROM 11b or the storage unit 12. The operation of the entire client terminal 10 is controlled by expanding and executing in the RAM 11c. Further, as shown in FIG. 9B, the control unit 11 (CPU 11a) executes an OS (Operating System) 16, a document creation application 17, a printer driver 18, and the like.

  The OS 16 is Windows (registered trademark), macOS (registered trademark), Android (registered trademark), iOS (registered trademark), or the like, and enables the document creation application 17 and the printer driver 18 to operate on the client terminal 10.

  The document creation application 17 is software that performs sentence creation, spreadsheet, image processing, and the like, and can create an input image (preferably a color input image) composed of coloring components, and specify a position where a white background should be added. To. Then, the printer driver 18 is read when a print instruction is given, and the data created by the document creation application 17 is transferred to the printer driver 18.

  The printer driver 18 converts the data created by the document creation application 17 in a page description language such as a print job (PJL (Printer Job Language), PS (PostScript), PCL (Printer Control Language), etc., in a language interpretable by the controller 20. Described in PDL (Page Description Language) data or PDF (Portable Document Format) data). This print job includes information on the position where the input image and the white background should be added.

  The storage unit 12 includes an HDD (Hard Disk Drive), an SSD (Solid State Drive), and the like, a program for the CPU 11a to control each unit, information on the processing function of the own device, data created by the document creation application 17, The print job created by the printer driver 18 is stored.

  The network I / F unit 13 includes a NIC (Network Interface Card), a modem, and the like, connects the client terminal 10 to the communication network 40, and transmits a print job to the controller 20.

  The display unit 14 includes a liquid crystal display (LCD), an organic EL (electroluminescence) display, and the like, and displays a document creation screen of the document creation application 17, a print setting screen of the printer driver 18, and the like.

  The operation unit 15 includes a mouse, a keyboard, and the like, and enables operations such as creation of an input image by the document creation application 17, designation of a position to which a white background should be added, print settings and a print instruction by the printer driver 18.

[controller]
The controller 20 is a control device that controls the printer 30. As shown in FIG. 10A, the controller 20 includes a control unit 21, a storage unit 22, a RIP processing unit 23, a network I / F unit 24, a printer I / F unit 25, a display unit and an operation as required. It consists of parts.

  The control unit 21 includes a CPU 21a and a memory such as a ROM 21b and a RAM 21c. The CPU 21a controls the operation of the entire controller 20 by developing the control program stored in the ROM 21b and the storage unit 22 in the RAM 21c and executing it. To do.

  The storage unit 22 is configured by an HDD, an SSD, and the like. A program for the CPU 21a to control each unit, a print job received from the client terminal 10, print image data generated based on the print job, and a color conversion table (printer profile) The color material amount limit value of the printer 30 and a list that associates device values and distribution ratios to be described later are stored.

  The RIP processing unit 23 is configured by an image processing ASIC (Application Specific Integrated Circuit) or the like, analyzes a print job received from the client terminal 10, receives information about an input image and a position to which a white background is to be added, A white background is converted into a multi-value bitmap to generate a multi-value pixel. Then, a color conversion process (for example, a color conversion process using an ICC profile) for matching the output product with a desired color is performed and output to the control unit 21.

  The network I / F unit 24 includes a NIC, a modem, and the like, connects the controller 20 to the communication network 40, and receives a print job and the like from the client terminal 10. The printer I / F unit 25 is a dedicated interface for connecting the controller 20 to the printer 30 and transmits print image data and the like to the printer 30 and instructs an output method.

  Further, as shown in FIG. 10B, the control unit 21 functions as a distribution ratio determination unit 26, a color material amount restriction processing unit 27, and the like.

  The distribution ratio determination unit 26 determines a distribution ratio that defines a reduction ratio of the color material amount with respect to color and white. Specifically, referring to a color conversion table (printer profile) or mathematical expression created in advance, a color value (brightness, saturation) corresponding to the selected device value is acquired, and based on the acquired color value The distribution ratio of the color material reduction amount shown below to white / color is determined, and the device value and the distribution ratio are associated with each other and registered in the list. At this time, the distribution ratio is determined so that the distribution ratio of the color material reduction amount to white decreases as the color value (lightness, saturation) of the input pixel increases. Further, a preferable range of color values for changing the distribution ratio of the color material reduction amount to white is defined. For example, if the brightness of the color component of the device value is less than the brightness of the secondary color solid, even if the white pixel value is reduced, the change in brightness is hardly noticed visually, and if the brightness is higher than the brightness of the primary color, the white pixel value is reduced. Therefore, it is possible to define a preferable brightness range by the brightness of the secondary color solid and the brightness of the primary color solid. In addition, since the color gamut changes depending on the color material (toner) used by the printer 30, a preferable brightness range may be defined based on the maximum brightness and the minimum brightness defined in the color space of the color component color material. it can. Further, when the lightness of the color component of the device value is within the preferred lightness range, the saturation of the color component of the device value is used as a background color instead of being used for characters (as usual for those skilled in the art). Less than a certain degree of saturation (in other words, a degree of saturation that is not easily associated with a color name), the change in saturation is not noticeable even when the white pixel value is reduced. Above the solid saturation, the reduction in saturation due to the reduction of the white pixel value is easily recognized visually, so the saturation of the secondary color (or the saturation and the secondary color A preferred saturation range can be defined by Similarly to the lightness, a preferable saturation range can be defined based on the maximum saturation and the minimum saturation defined in the color space of the color material of the color component. If the color value of the color component of the device value is within the defined range, the higher the lightness (or high saturation), the smaller the distribution ratio of the color material reduction amount to white and the range in which the color value is defined. When the value exceeds 1, the distribution ratio of the color material reduction amount to white is set to almost 0. When the color value is less than the defined range, the distribution ratio of the color material reduction amount to white is almost 1 (100%). To be.

  The color material amount restriction processing unit 27 reduces the color material amount so that the total value of the color color material amount and the white color material amount in a predetermined pixel is equal to or less than a predetermined color material amount limit value, Instructs the printer 30 to print. At this time, the reduction ratio between the color material amount reduction amount and the white color material amount reduction amount is changed according to the color information of the image information. Specifically, for each input pixel constituting the input image, the color material reduction amount is calculated by subtracting the color material amount limit value from the total value of the pixel value of the input pixel and the pixel value of the white background. Referring to the above list, the distribution ratio associated with the device value corresponding to the pixel value of each input pixel is acquired, and based on the acquired distribution ratio, the calculated color material reduction amount is compared with the input pixel and white Distribute to the ground to limit the amount of color and white color material.

  The distribution ratio determination unit 26 and the color material amount restriction processing unit 27 may be configured as hardware, or the control unit 21 may be configured as the distribution ratio determination unit 26 and the color material amount restriction processing unit 27 (particularly, the color material amount). The color material amount restriction program may be configured to function as the restriction processing unit 27), and the CPU 21a may execute the color material amount restriction program.

[Printer]
The printer 30 is a printing apparatus such as an electrophotographic printer capable of forming an image using color (CMYK) and white (background) color materials, and performs printing based on instructions from the controller 20. As shown in FIG. 11, the printer 30 includes a control unit 31, a controller I / F unit 32, a panel operation unit 33, a print processing unit 34, and the like.

  The control unit 31 includes a CPU 31a and a memory such as a ROM 31b and a RAM 31c. The CPU 31a controls the operation of the entire printer 30 by developing and executing a control program stored in the ROM 31b on the RAM 31c.

  The controller I / F unit 32 is a dedicated interface for connecting the printer 30 to the controller 20 and receives print image data and the like from the controller 20.

  The panel operation unit 33 is a touch panel or the like in which a touch sensor made of a grid-like transparent electrode is formed on a display unit such as an LCD, and displays various screens related to printing and enables various operations related to printing.

  The print processing unit 34 is a print engine that forms an image on a sheet based on print image data received from the controller 20. Specifically, the photosensitive drum charged by the charging device is irradiated with light corresponding to the image from the exposure device to form an electrostatic latent image, and each color toner charged by the developing device is attached and developed, The toner image is primarily transferred to the transfer belt, secondarily transferred from the transfer belt to the paper, and further, a fixing device fixes the toner image on the paper. The print processing unit 34 may separately perform arbitrary correction in order to stabilize image formation.

  7 to 11 show an example of the printing system of this embodiment, and the configuration and control of each device can be changed as appropriate. For example, in FIG. 10, the control unit 21 has the functions of the distribution ratio determination unit 26 and the color material amount restriction processing unit 27, but the RIP processing unit 23 includes the distribution ratio determination unit 26 and the color material amount restriction processing unit 27. You may make it give a function.

  Hereinafter, the operation of the controller 20 configured as described above will be described. The CPU 21a executes the processing of each step shown in the flowcharts of FIGS. 12 and 13 by developing and executing the color material amount restriction program stored in the ROM 21b or the storage unit 22 in the RAM 21c. It is assumed that a white background should be given to an arbitrary position of the input image (CMYK) by some method. The input image is an image (preferably a color input image) made of a color component (for example, CMYK). The format of the white background information is arbitrary. For example, it may be a special color version of a general DTP (Desktop publishing) application or a dedicated format.

  First, the color material reduction amount distribution ratio determination processing will be described with reference to FIG. This color material reduction amount distribution ratio determination process may be performed once before the color material amount restriction process for the input image.

  The control unit 21 (distribution ratio determining unit 26) of the controller 20 acquires a printer profile for acquiring color values created in advance from the storage unit 22 or the like (S101). Here, an ICC (International Color Consortium) profile using only CMYK toner without using a white background is used. In addition, combinations of coloring components (CMYK) excluding the white background (e.g. 9 points for each color (0, 10, 20, 30, 40, 55, 70, 85 , 100%)), as long as it is possible to obtain color values when printed on white paper, the ICC profile format is not necessary. Further, the ICC profile may include information on color values when a white background is used.

  Next, the control unit 21 (distribution ratio determination unit 26) selects one color device value (CMYK value) (S102). At that time, for example, 9 points of each color (0, 10, 20, 30, 40, 55, 70, 85, etc.) are provided so that the list for associating device values and distribution ratios can cover substantially all combinations by interpolation calculation. 100%) combination. Then, the following calculation is sequentially performed on the device values selected from them.

  First, the control unit 21 (distribution ratio determination unit 26) acquires a color value (L * a * b *) (S103). When the ICC profile is used, the color value corresponding to the device value can be acquired by referring to a so-called A2B table (CMYK → L * a * b * color conversion table). For example, in the case of device values C, M, Y, K = 10, 10, 10, 40, L * = 60. Although the color conversion table is used here, information that can acquire the color value corresponding to the device value may be used. For example, the color value may be acquired using an equation.

  Next, the control unit 21 (distribution ratio determining unit 26) determines the distribution ratio of the color material reduction amount from the acquired color value (S104). This will be specifically described below.

  For example, as shown in FIG. 14, as the color value corresponding to the pixel value of the color component becomes higher in brightness (L * becomes larger), the distribution ratio of the color material reduction amount to white becomes smaller (white relative to The distribution ratio is determined so that the color is reduced by a relatively large amount. At that time, as the brightness becomes higher, a range of brightness that reduces the distribution ratio of the color material reduction amount to white is defined, and depending on whether the brightness corresponding to the pixel value of the color component is within that range, The distribution ratio of the color material reduction amount to white is determined. The lower limit (low brightness side) of this range has a p-point of 0 to 50, preferably 35 to 45 of the secondary solid color brightness (for example, B solid brightness), and the upper limit of the range (high brightness side) ) Q can be 60 to 85, preferably 70 to 80 of the primary color solidity (for example, the brightness of the solid Y).

  Further, since the color gamut changes depending on the color material (toner) used by the printer 30, as shown in FIG. 15, the preferable values of the p point and the q point are defined by the color space of the color component color material. It can also be defined as a ratio to the brightness range (maximum brightness, minimum brightness). For example, the lightness ratio at point p is (lightness at point p-minimum lightness) / (maximum lightness-minimum lightness), which can be set from 0.3 to 0.4, and the lightness ratio at point q should be 0.7 to 0.8. Can do.

  Further, in the case where the brightness corresponding to the pixel value of the color component is within the above range, as the color value corresponding to the pixel value of the color component becomes higher in saturation (C * increases) as shown in FIG. The distribution ratio is determined so that the distribution ratio of the material reduction amount to white becomes small (remaining a relatively large amount of white and reducing the color relatively). At that time, a saturation range is defined in which the distribution ratio of the color material reduction amount to white is reduced as the saturation becomes higher, and depending on whether the saturation corresponding to the pixel value of the color component is within the range or not. The distribution ratio of the color material reduction amount to white is determined. The lower limit (low saturation side) of this range can be 0 to 20, preferably 5 to 15 called so-called low saturation, and the upper limit (high saturation side) of the s point is 30 to 60. The saturation of the secondary solid color may be preferably 40 to 50 (for example, the solid saturation of B). Since the degree of influence on visual evaluation is lower than the lightness with respect to the saturation, it is preferable to use the lightness together with the lightness rather than determining the distribution ratio by the saturation alone. In addition, regarding the saturation, the saturation range may be defined using only the upper limit.

  Similarly to the lightness, the color gamut changes depending on the color material (toner) used by the printer 30. Therefore, as shown in FIG. 17, the preferable values of the r and s points are the colors at the lightness and hue angle. It can also be defined by the ratio of the component to the saturation range (maximum saturation, minimum saturation). For example, the saturation ratio of the r point is (saturation of the r point−0) / (maximum saturation−0), which can be 0 to 0.2, and the saturation ratio of the s point is 0.4 to 0.6. can do.

  Further, as a substitute for the saturation, a preferable range can be defined by the amount of complementary color of the device value and the amount of achromatic color (K). For example, the smaller the amount of complementary color of the device value (the smaller the value of chromatic color = C, M, Y, min (C, M, Y) / sum (C, M, Y)), the more the color material reduction amount The distribution ratio can be determined so that the distribution ratio to white becomes small, and preferably 0.15 or less as a substitute for the s point. Also, the smaller the amount of achromatic color (K) in the device value (the smaller the value of K / sum (C, M, Y, K)), the smaller the distribution ratio of color material reduction to white is. The ratio can be determined and is preferably 0.15 or less as a substitute for the s point.

  Returning to the flowchart of FIG. 12, the control unit 21 (distribution ratio determining unit 26) associates the device value selected in S102 with the distribution ratio determined in S104 and stores them in the list (S105). For example, in the case of device values C, M, Y, K = 10, 10, 10, 40, since the distribution ratio to white is 0.5, these are associated and stored in the list. This list is preferably stored in association with the printer profile used or information that can identify the printer 30.

  Next, the control unit 21 (distribution ratio determining unit 26) determines whether the processing has been completed for all the scheduled device values (S106), and if there is an unprocessed device value (No in S106). Returning to S102, the same processing is repeated.

  Next, the color material amount restriction process for the input image will be described with reference to FIG.

  The control unit 21 (color material amount restriction processing unit 27) of the controller 20 acquires a list that associates the color material amount restriction value of the printer 30 and the device value with the distribution ratio of the color material reduction amount from the storage unit 22 or the like. (S201).

  Next, the control unit 21 (color material amount restriction processing unit 27) acquires one pixel value (white + CMYK value) from the input image that is the target of the color material amount restriction process (S202). In order to improve the overall processing speed, for example, the color material amount restriction process can be performed using an arbitrary technique such as simultaneously performing the color material amount restriction process on pixels having the same CMYK value.

Next, the control unit 21 (color material amount restriction processing unit 27) calculates a color material reduction amount from the pixel value (white + CMYK value) and the color material amount restriction value as follows (S203).
Color material reduction amount = Pixel value (white + CMYK value)-Color material amount limit value

  Next, the control unit 21 (color material amount restriction processing unit 27) uses only the CMYK value of the pixel values (white + CMYK value) acquired in S202 to calculate the device value and the distribution ratio of the color material reduction amount. The distribution ratio of the color material reduction amount to white is acquired from the list to be associated (S204).

Next, based on the acquired distribution ratio to white, the control unit 21 (color material amount restriction processing unit 27) distributes the color material reduction amount to white / color as described below (S205).
White reduction amount = Color material reduction amount distribution ratio to white x Color material reduction amount Color reduction amount = (1-Distribution ratio of color material reduction amount to white) x Color material reduction amount

Next, the control unit 21 (color material amount restriction processing unit 27) performs a color material reduction process on each of white / color as follows (S206). Note that the color reduction method (distribution in CMYK) for achieving the color material reduction amount is arbitrary, and a known technique can be used.
White pixel value after color material reduction processing = white input pixel value-white reduction amount Color (CMYK) pixel value after color material reduction processing = color input pixel value-color reduction amount

  Next, the control unit 21 (color material amount restriction processing unit 27) determines whether or not the processing of all the pixels of the scheduled input image has been completed (S207), and if there is an unprocessed pixel (No in S207). Returning to S202, the same processing is repeated. Thereafter, the controller 20 transfers the image data after the color material amount restriction process to the printer 30, and the printer 30 performs a printing process based on the transferred image data. Note that any known technique can be used for a specific format of image data, a transfer method, and other controls.

  In this way, when forming an image using color (CMYK) and white (background) color materials, the color material amount limit is such that the output pixel value is less than or equal to the predetermined limit value with respect to the total of the input pixel values. When determining the color material amount limit (especially 300%) by determining the distribution ratio of the color material reduction amount to white / color according to the color value (lightness or saturation) corresponding to the pixel value of the color component (Severe conditions such as below), it is possible to reduce the amount of color material of both white and color with an optimal balance (distribute the reduction amount), and to suppress deterioration of color reproduction.

  In addition, this invention is not limited to description of the said Example, The structure and control can be suitably changed unless it deviates from the meaning of this invention.

  For example, in the above-described embodiment, within a preferable lightness range or saturation range, the distribution ratio of the color material reduction amount to white decreases (correlation with a linear function) with respect to the increase in lightness or saturation, Although the case where the distribution ratio of the color material reduction amount to white is constant outside the above range is exemplified, it is sufficient that the distribution ratio to white decreases as the brightness and saturation increase as a whole. For example, the ratio of the change in the distribution ratio within the range and the value of the distribution ratio outside the range can be set as appropriate.

  In the above embodiment, an electrophotographic printer is exemplified as the printer 30, but the color material amount restriction processing method of the present invention is similarly applied to an inkjet printer using UV (ultraviolet) curable ink or the like. Can do.

  The present invention operates with a control device that controls a printing apparatus that performs printing by applying a white background to a color input image, a color material amount restriction method that controls color material amount restriction during printing, and the control device. The present invention can be used for a color material amount restriction program and a recording medium on which the color material amount restriction program is recorded.

10 Client terminal 11 Control unit 11a CPU
11b ROM
11c RAM
12 storage unit 13 network I / F unit 14 display unit 15 operation unit 16 OS
17 Document creation application 18 Printer driver 20 Controller 21 Control unit 21a CPU
21b ROM
21c RAM
22 Storage Unit 23 RIP Processing Unit 24 Network I / F Unit 25 Printer I / F Unit 26 Distribution Ratio Determination Unit 27 Color Material Amount Limiting Processing Unit 30 Printer 31 Control Unit 31a CPU
31b ROM
31c RAM
32 Controller I / F unit 33 Panel operation unit 34 Print processing unit 40 Communication network

Claims (25)

A control device that controls a printing apparatus that performs printing using a color coloring material and a white coloring material based on image information,
The color that reduces the color material amount so that the total value of the color color material amount and the white color material amount at a predetermined pixel is equal to or less than a predetermined color material amount limit value, and instructs the printing apparatus to perform printing It has a material amount restriction processing part,
The color material amount restriction processing unit changes a reduction ratio between the color material amount reduction amount and the white color material amount reduction amount according to the color information of the image information.
A control device characterized by that. A color value corresponding to the selected device value is acquired, and based on the color value, a distribution ratio that defines a reduction ratio of the color material amount with respect to color and white is determined, and the device value and the distribution ratio are determined. It further comprises a distribution ratio determining unit that registers and registers in the list,
The color material amount restriction processing unit calculates a color material reduction amount by subtracting the color material amount restriction value from a total value of a pixel value of each color input pixel and a white background pixel value, and the list The distribution ratio associated with the device value corresponding to the pixel value of each of the input pixels is acquired, and the calculated color material reduction amount is calculated based on the acquired distribution ratio. And the amount of the color material and the white color material are limited.
The control device according to claim 1. The distribution ratio determination unit determines the distribution ratio so that the distribution ratio of the color material reduction amount to white decreases as the brightness of the color component of the device value increases.
The control device according to claim 2. The distribution ratio determining unit changes the distribution ratio of the color material reduction amount to white in a lightness range from the lightness of the secondary color solid to the lightness of the primary color solid.
The control device according to claim 3. The distribution ratio determining unit defines the lightness range based on a maximum lightness and a minimum lightness defined in a color space of a color material of a color component used by the printing apparatus.
The control device according to claim 4. In the case where the brightness of the color component of the device value is within the brightness range, the distribution ratio determination unit decreases the distribution ratio of the color material reduction amount to white as the saturation of the color component of the device value increases. Determining the distribution ratio so that
The control device according to claim 4 or 5, wherein The distribution ratio determining unit changes the distribution ratio of the color material reduction amount to white in a saturation range up to the saturation of the secondary color.
The control apparatus according to claim 6. The distribution ratio determining unit distributes the color material reduction amount to white as the amount of complementary color or achromatic color of the device value decreases when the lightness of the color component of the device value is within the lightness range. Determining the distribution ratio such that the ratio is small;
The control device according to claim 4 or 5, wherein Including the control device according to any one of claims 1 to 8,
A printing apparatus characterized by that. A color material amount limiting method in a printing system including a printing apparatus that performs printing using a color material and a white color material based on image information,
The color that reduces the color material amount so that the total value of the color color material amount and the white color material amount at a predetermined pixel is equal to or less than a predetermined color material amount limit value, and instructs the printing apparatus to perform printing Execute the material limit process,
In the color material amount restriction process, the reduction ratio between the color material amount reduction amount and the white color material amount reduction amount is changed according to the color information of the image information.
A color material amount limiting method characterized by the above. A color value corresponding to the selected device value is acquired, and based on the color value, a distribution ratio that defines a reduction ratio of the color material amount with respect to color and white is determined, and the device value and the distribution ratio are determined. Further execute a distribution ratio determination process for registering in association with the list,
In the color material amount restriction process, a color material reduction amount is calculated by subtracting the color material amount restriction value from a total value of a pixel value of each color input pixel and a white background pixel value, and the list is calculated. Referring to, the distribution ratio associated with the device value corresponding to the pixel value of each of the input pixels is acquired, and the calculated color material reduction amount is calculated as the input pixel based on the acquired distribution ratio. Distributing to the base to limit the amount of color and white color material,
The color material amount limiting method according to claim 10. In the distribution ratio determination process, the distribution ratio is determined so that the distribution ratio of the color material reduction amount to white decreases as the brightness of the color component of the device value increases.
The color material amount limiting method according to claim 11. In the distribution ratio determination process, the distribution ratio of the color material reduction amount to white is changed in a lightness range from the lightness of the secondary color solid to the lightness of the primary color solid.
The color material amount limiting method according to claim 12. In the distribution ratio determination process, the brightness range is defined based on the maximum brightness and the minimum brightness defined in the color space of the color material of the color component used by the printing apparatus.
The color material amount limiting method according to claim 13. In the distribution ratio determination process, when the lightness of the color component of the device value is within the lightness range, the distribution ratio of the color material reduction amount to white decreases as the saturation of the color component of the device value increases. Determining the distribution ratio so that
The color material amount limiting method according to claim 13 or 14, characterized in that: In the distribution ratio determination process, in the saturation range up to the saturation of the secondary color, the distribution ratio of the color material reduction amount to white is changed.
The color material amount limiting method according to claim 15. In the distribution ratio determination processing, when the lightness of the color component of the device value is within the lightness range, the color material reduction amount is distributed to white as the amount of complementary color or achromatic color of the device value decreases. Determining the distribution ratio such that the ratio is small;
The color material amount limiting method according to claim 13 or 14, characterized in that: A color material amount restriction program that operates on a control device that controls a printing device that performs printing using a color material and a white color material based on image information,
In the control device,
The color that reduces the color material amount so that the total value of the color color material amount and the white color material amount at a predetermined pixel is equal to or less than a predetermined color material amount limit value, and instructs the printing apparatus to perform printing Execute material limit processing,
In the color material amount restriction process, in accordance with the color information of the image information, the reduction ratio between the color material amount reduction amount and the white color material amount reduction amount is changed.
A color material amount restriction program characterized by that. In addition to the control device,
A color value corresponding to the selected device value is acquired, and based on the color value, a distribution ratio that defines a reduction ratio of the color material amount with respect to color and white is determined, and the device value and the distribution ratio are determined. Execute distribution ratio determination processing to be registered in the list in association,
In the color material amount restriction process, a color material reduction amount is calculated by subtracting the color material amount restriction value from a total value of a pixel value of each color input pixel and a white background pixel value, and the list is calculated. Referring to, the distribution ratio associated with the device value corresponding to the pixel value of each of the input pixels is acquired, and the calculated color material reduction amount is calculated as the input pixel based on the acquired distribution ratio. Distributing to the base to limit the amount of color and white color material,
The color material amount restriction program according to claim 18, wherein: In the distribution ratio determination process, the distribution ratio is determined so that the distribution ratio of the color material reduction amount to white decreases as the brightness of the color component of the device value increases.
The color material amount restriction program according to claim 19. In the distribution ratio determination process, the distribution ratio of the color material reduction amount to white is changed in a lightness range from the lightness of the secondary color solid to the lightness of the primary color solid.
21. The color material amount restriction program according to claim 20, wherein In the distribution ratio determination process, the brightness range is defined based on the maximum brightness and the minimum brightness defined in the color space of the color material of the color component used by the printing apparatus.
The color material amount restriction program according to claim 21, wherein: In the distribution ratio determination process, when the lightness of the color component of the device value is within the lightness range, the distribution ratio of the color material reduction amount to white decreases as the saturation of the color component of the device value increases. Determining the distribution ratio so that
The color material amount restriction program according to claim 21 or 22, In the distribution ratio determination process, in the saturation range up to the saturation of the secondary color, the distribution ratio of the color material reduction amount to white is changed.
The color material amount restriction program according to claim 23. In the distribution ratio determination processing, when the lightness of the color component of the device value is within the lightness range, the color material reduction amount is distributed to white as the amount of complementary color or achromatic color of the device value decreases. Determining the distribution ratio such that the ratio is small;
The color material amount restriction program according to claim 21 or 22,

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