JP4471021B2 - Color printing control apparatus, color printing control method, and color printing control program - Google Patents

Description

  The present invention relates to a color print control device, a color print control method, and a color print control program, and more particularly, to a color print control device, a color print control method, and a color having a mode for printing while reducing colorant consumption The present invention relates to a print control program.

  Many color printing apparatuses perform full color printing by superimposing images represented by four color materials of cyan (C), magenta (M), yellow (Y), and black (K) on a print medium. Realized. For this reason, color printing consumes more color material and is expensive to print compared to monochrome (grayscale) printing in which an image is printed only with black (K).

  For example, when the test chart defined in ISO / IEC 24712: 2006 “Color test pages for measurement of office equipment consumable yield” is printed with a full-color laser beam printer, it is compared with the case where the same test chart is printed in gray scale. Thus, approximately twice as much color material (in this case, toner) is consumed. In addition, 216 color patches (RGB 216 color patches) represented by combinations of 0%, 20%, 40%, 60%, 80%, and 100% of each color of red (R), green (G), and blue (B) ) In color printing consumes approximately three times as much color material as compared to the same color patch printed in grayscale.

  By the way, in printing applications that do not necessarily require high image quality, such as calibration of a printed document and layout confirmation, it is desirable to reduce the printing cost.

  In response to such a request, there is a color printing apparatus having a printing mode that reduces the printing cost by suppressing the consumption of color materials. That is, as means for realizing a printing mode that suppresses consumption of color materials, (1) a method of printing after converting to gray scale, (2) a method of printing by reducing the image density of each color material color, and (3) each color material A method of reducing the total number of pixels by thinning and printing the color pixels is employed.

  However, (1) in the method of printing after converting to gray scale, the color information is discarded, so that what is emphasized with a red color character or the like in a document has a density lower than that of a black character. The effect of can not be confirmed. Yellow is originally a color with high brightness, and when converted to gray scale, it becomes very light and cannot be distinguished from the printing ground (white). Further, (2) in the method of printing by reducing the image density of each color material color, the image density is reduced to about 50% in order to print the above-described RGB216 color patch at the color material consumption amount at the time of gray scale printing. There is a need. However, in many color printing apparatuses, gradation reproduction is performed using a dither screen, so that a printed image is formed with small dither dots by lowering the density, and the visibility of small size characters is particularly poor. In addition, (3) the method of printing by thinning out pixels of each color material color results in a blurred image, and the visibility of small-size characters is particularly poor. Moreover, if these methods are used to maintain and improve the visibility, there is a problem that the reduction rate of the color material consumption does not increase.

  On the other hand, by correcting the saturation or lightness of a pixel, specifying a gray pixel to be printed using a combination of color and ink, and correcting the pixel to print using only black ink, it is consumed during printing. A technique for saving color materials has been proposed (see Patent Document 1).

However, the technique disclosed in Patent Document 1 is a color material reduction process for reducing color material consumption by intervening in print data on a host computer or on a communication path between a host computer and a color printing apparatus. Is to do. Here, for example, in PostScript (registered trademark), objects defined in various color spaces can be described in one print data. For this reason, in the technique described in Patent Document 1, the color material reduction processing needs to correspond to various print data formats such as PDL (Page Description Language) and color space definitions, and corresponds individually. Therefore, there is a problem that many data resources are required. In recent years, a color printing apparatus having an interface for connecting a memory device and having a function of reading and printing data stored in the memory device (memory direct printing function) has been provided. The technique described in Patent Document 1 also has a problem that it cannot cope with printing completed in a color printing apparatus without using such a host computer.
JP 2005-512199 A

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a host without requiring many data resources to cope with various print data formats and color spaces. A color printing control apparatus, a color printing control method, and a color printing control program that can be applied to printing without using a computer, and that can reduce consumption of color materials without drastically reducing the visibility of printed images. Is to provide.

  The above object of the present invention is achieved by the following means.

(1) A color printing control apparatus that performs control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium, and the consumption of the color material A determination unit that determines whether or not a color material reduction printing mode for printing with a reduced amount is set, and if the determination unit determines that the color material reduction printing mode is set, printing is performed. has an output portion in which the color material reduction process outputs the color material reduction processed data subjected to each pixel of the converted bitmap color material color to be used, the color material reducing process, each Among the plurality of chromatic color material components of the pixel, while reducing the density of the chromatic color material component having a density larger than the reference value determined from the density of the plurality of chromatic color material components, the reference value Chromatic color material composition with lower density than And saturation converter to reduce the saturation by increasing the concentration, is carried out after the saturation conversion, replacing at least part of the achromatic component caused by overlapping of a plurality of color materials at the achromatic color material A color printing control apparatus comprising undercolor removal / black plate generation.

  (2) In the saturation conversion, a saturation conversion rate indicating a ratio of saturation after conversion to saturation before conversion is set for each pixel according to the saturation of the pixel to be processed. The color printing control apparatus according to (1) above.

  (3) In the saturation conversion, the saturation conversion rate for the first pixel is made larger than the saturation conversion rate for the second pixel having a lower saturation than the first pixel. The color printing control apparatus according to (2) above.

( 4 ) The color printing control apparatus according to any one of (1) to ( 3 ), wherein the color material reduction processing further includes density conversion for reducing density.

(5) In the density conversion, in accordance with the density of the pixel to be processed, above, characterized in that the density conversion ratio indicating the ratio of the density after the conversion to the concentration before the conversion for each pixel is set (4) A color printing control apparatus according to claim 1.

(6) In the density conversion, the (5, characterized in that the first density conversion rate for the pixel, is larger than the density conversion rate for the second pixel a lower concentration than the first pixel ) The color printing control apparatus according to.

( 7 ) The color material reduction process includes a first process and a second process having a different process content from the first process, and according to the attribute of the pixel on which the color material reduction process is performed. The color printing control apparatus according to any one of (1) to ( 6 ), wherein a color material reduction process applied to the pixel is switched to the first process or the second process. .

(8) said attributes include a type of print object to which the pixel belongs, the type of the printing object, according to the above (7), characterized in that are classified into at least other than image objects and image objects, Color printing control device.

( 9 ) Parameters of processes executed in the first process and the second process so that the color material reduction amount for the pixels of the image object is larger than the color material reduction amount for the pixels other than the image object. The color printing control apparatus according to ( 8 ), wherein: is set.

(1 0 ) The above parameters (1) to ( 9 ) are characterized in that processing parameters to be executed in the color material reduction processing are set based on a user instruction in an operation unit on the color printing control apparatus. The color printing control apparatus according to any one of the above.

(1 1 ) The above parameters (1) to (1) are characterized in that a parameter of processing executed in the color material reduction processing is set based on a command included in print data input to the color printing control apparatus. The color printing control apparatus according to any one of (1 0 ).

(1 2 ) A color printing control apparatus that prints a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium, and reduces consumption of the color material. A determination unit that determines whether or not a color material reduction printing mode for printing is set, and the color printing control device determines that the color material reduction printing mode is set by the determination unit. A color conversion unit that performs color conversion to convert the input color data into a color material color to be used for printing using a color conversion profile for color material reduction that can simultaneously execute color material reduction processing; The color material reduction processing is performed for chromatic color material components having a density larger than a reference value determined from the density of the plurality of chromatic color material components among the plurality of chromatic color material components of each pixel. While reducing the concentration And saturation converter to reduce the saturation by increasing the concentration of chromatic coloring material component having a smaller density than Jun'ne, performed after the chroma conversion, achromatic caused by superposition of plural color materials A color printing control apparatus comprising: under color removal / black plate generation in which at least a part of a component is replaced with an achromatic color material.

(1 3 ) In the saturation conversion, a saturation conversion rate indicating a ratio of saturation after conversion to saturation before conversion is set for each pixel according to the saturation of the pixel to be processed. The color printing control apparatus according to (1 2 ).

(1 4 ) In the saturation conversion, the saturation conversion rate for the first pixel is set larger than the saturation conversion rate for the second pixel having a lower saturation than the first pixel. The color printing control apparatus according to (1 3 ) above.

(1 5 ) The color printing control apparatus according to any one of (1 2 ) to (1 4 ), wherein the color material reduction processing further includes density conversion for reducing density.

(1 6 ) In the density conversion, the density conversion rate indicating the ratio of the density after conversion to the density before conversion is set for each pixel according to the density of the pixel to be processed (1) 5 ) The color printing control apparatus according to the above.

( 17 ) In the density conversion, the density conversion rate for the first pixel is set larger than the density conversion rate for the second pixel having a lower density than the first pixel. 6 ) The color printing control apparatus described in the above.

( 18 ) The color material reduction color conversion profile includes a first profile and a second profile having a different color material reduction processing content from the first profile, and the pixel to which the color conversion is performed. According to the attribute, the color material reduction color conversion profile used for color conversion applied to the pixel is switched to the first profile or the second profile, (1 2 ) to ( 17 ) The color printing control apparatus according to any one of the above.

(19) the attribute comprises the type of printing object to which the pixel belongs, the type of the printing object, according to the above (18), wherein are classified into at least other than image objects and image objects, that Color printing control device.

(2 0 ) Colors executed in the first profile and the second profile so that the color material reduction amount for the pixels of the image object is larger than the color material reduction amount for the pixels other than the image object. The color printing control apparatus as described in ( 19 ) above, wherein conversion parameters are set.

(2 1 ) The above (1) to (2 0 ), wherein in the under color removal / black plate generation, all achromatic components generated by superposition of a plurality of color materials are replaced with achromatic color materials. The color printing control apparatus according to any one of the above.

(2 2 ) A color printing control method for performing control for printing a color image by superimposing an achromatic color material containing at least black and a plurality of chromatic color materials on a print medium, A determination step for determining whether or not a color material reduction print mode for printing with reduced consumption is set, and if it is determined in the determination step that a color material reduction print mode is set, printing is performed. An output step of outputting color material reduction processed data that has been subjected to color material reduction processing for each pixel of the bitmap converted to the color material color used for the color material reduction process, Among the plurality of chromatic color material components of each pixel, while reducing the density of the chromatic color material component having a density greater than a reference value determined from the density of the plurality of chromatic color material components, the reference Less than value And saturation converter to reduce the saturation by increasing the concentration of chromatic coloring material component having a degree, take place after the chroma conversion, at least part of the achromatic component caused by overlapping of a plurality of color materials A color printing control method comprising: undercolor removal / black plate generation for substituting an achromatic color material.

(2 3 ) A color printing control method for performing control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium, A determination step for determining whether or not a color material reduction print mode for printing with reduced consumption is set, and an input when it is determined in the determination step that the color material reduction print mode is set A color conversion step for performing color conversion to convert the color data into a color material color used for printing using a color material reduction color conversion profile capable of performing color material reduction processing simultaneously. The color material reduction processing includes: a density of a chromatic color material component having a density greater than a reference value determined from the density of the plurality of chromatic color material components among the plurality of chromatic color material components of each pixel. Reduce In person, the chroma conversion that reduces the saturation by increasing the concentration of chromatic coloring material component having a smaller density than the reference value is performed after the saturation conversion, superposition of a plurality of color materials A color printing control method comprising: undercolor removal / black plate generation in which at least a part of the achromatic color component generated in step 1 is replaced with an achromatic color material.

(2 4 ) A color print control program for performing control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium, A determination procedure for determining whether or not a color material reduction print mode for printing with reduced consumption is set, and if it is determined in the determination procedure that a color material reduction print mode is set, printing is performed. Output the color material reduction processed data for which color material reduction processing has been performed on each pixel of the bitmap converted to the color material color used in The material reduction process reduces the density of a chromatic color material component having a density greater than a reference value determined from the density of the plurality of chromatic color material components among the plurality of chromatic color material components of each pixel. On the other hand And saturation converter to reduce the saturation by increasing the concentration of chromatic coloring material component having a smaller density than the reference value is performed after the saturation conversion, no caused by overlapping of a plurality of color materials A color printing control program comprising: undercolor removal / black plate generation for replacing at least part of a chromatic component with an achromatic color material.

(2 5 ) A color print control program for performing control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium, A determination procedure for determining whether or not a color material reduction print mode for printing with reduced consumption is set, and an input when it is determined in the determination procedure that a color material reduction print mode is set A color conversion procedure for performing color conversion for converting the obtained color data into a color material color to be used for printing using a color material reduction color conversion profile capable of simultaneously executing color material reduction processing. The color material reduction processing is executed, and among the plurality of chromatic color material components of each pixel, the chromatic color having a density larger than a reference value determined from the density of the plurality of chromatic color material components color While reducing the concentration of the components, the chroma conversion that reduces the saturation by increasing the concentration of chromatic coloring material component having a smaller density than the reference value is performed after the saturation conversion, a plurality A color printing control program, comprising: undercolor removal / black plate generation in which at least a part of an achromatic color component generated by superimposing color materials is replaced with an achromatic color material.

(2 6 ) A computer-readable recording medium on which the color printing control program according to (2 4 ) or (2 5 ) is recorded.

  According to the present invention, it can be applied to printing without using a host computer without requiring many data resources to cope with various print data formats and color spaces, and the visibility of printed images is extremely reduced. This makes it possible to reduce the color material consumption.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a color printing apparatus 1 to which a color printing control apparatus according to a first embodiment of the present invention is applied.

  A color printing apparatus 1 shown in FIG. 1 is a color printing apparatus that prints a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium. This is an electrophotographic color printer that uses toner of four colors, cyan (C), magenta (M), yellow (Y), and black (K).

  The color printing apparatus 1 is developed in a CPU 11 that controls each part in the color printing apparatus 1 and various arithmetic processes, an image memory 12 that stores (printing) image data obtained by analyzing input print data, and an image memory An attribute memory 13 for storing attribute data of an object to which each pixel (pixel) of the image data being assigned belongs, a memory access control unit 14 for sequentially sending image data and attribute data from the image memory 12 and the attribute memory 13, respectively, color Output data of first color material reduction processing unit 15 and second color material reduction processing unit 16, first color material reduction processing unit 15 or output data of second color material reduction processing unit 16 for reducing material consumption The first selection circuit 17 for selecting one of the two according to the attribute data, the image read from the image memory Image data that can be formed using a tone reproduction method such as a dither method, a second selection circuit 18 that selects either the edge data (pixel data) or the output data of the first selection circuit 17 according to the print mode signal. It has a screening processing unit 19 to be generated and an image forming circuit 20 that performs printing control based on the sent image data.

  The first color material reduction processing unit 15 and the second color material reduction processing unit 16 are functional blocks that independently convert the CMYK density of the image data.

  The first color material reduction processing unit 15 includes a first saturation conversion circuit 151, a first density conversion circuit 152, and a first under color removal / black plate generation circuit 153, and the second color material reduction processing unit 16. Includes a second saturation conversion circuit 161, a second density conversion circuit 162, and a second undercolor removal / black plate generation circuit 163. Here, the first saturation conversion circuit 151 and the second saturation conversion circuit 161 are circuits for reducing the saturation, and the first density conversion circuit 152 and the second density conversion circuit 162 are for reducing the density. The first undercolor removal / black plate generation circuit 153 and the second undercolor removal / black plate generation circuit 163 are formed of achromatic color materials at least part of the achromatic components generated by superimposing a plurality of color materials. This is a circuit for replacement.

  The conversion characteristics of the circuits included in the first color material reduction processing unit 15 and the second color material reduction processing unit 16 are determined by the (conversion) parameters stored in the first register 111 and the second register 112. . The parameter is set in the first register 111 and the second register 112 by the CPU 11. Therefore, the first color material reduction processing unit 15 and the second color material reduction processing unit 16 have different processing contents according to the difference in parameters.

  In the present embodiment, the first saturation conversion circuit 151 and the second saturation conversion circuit 161 include a saturation conversion rate indicating the ratio of the saturation after conversion to the saturation before conversion, the first density conversion circuit 152, and The second density conversion circuit 162 includes a density conversion rate indicating a ratio of the density after conversion to the density before conversion, the first under color removal / black plate generation circuit 153, and the second under color removal / black plate generation circuit 163. In this case, a lower color removal ratio indicating how much of the achromatic color component generated by superimposing a plurality of color materials is replaced with the achromatic color material is set as a parameter.

  The image forming circuit 20 performs control to print an image based on the received image data on a recording medium such as paper using a known electrophotographic image forming process, for example.

  In FIG. 1, the components of the color printing apparatus 1 that are mainly related to the present invention are described, and the color printing apparatus 1 may include components other than the above-described components. Some of the above-described components may not be included.

  The color printing apparatus 1 configured as described above includes a color material reduction printing mode for printing while reducing the color material consumption, and operates as follows. In the present invention, the term “coloring material” is used as a concept including toner, ink, and the like. That is, the present invention can be applied not only to an electrophotographic image forming method, but also to other image forming methods such as an ink jet method in which the amount of color material consumed varies depending on an image.

  First, the color printing apparatus 1 receives print data from an external device (host computer) such as a PC (personal computer) outside the color printing apparatus 1.

  The CPU 11 analyzes the print data input to the data receiving circuit via a printer interface (not shown), and converts the color data into CMYK, which is a color material color used in the color printing apparatus 1, in the image memory 12 according to the print data. The image data of 32 bits (8 bits × 4 colors) data is developed. Further, the CPU 11 sets attribute data indicating the attribute of each pixel of the image data developed in the image memory 12 in the attribute memory 13. The attribute includes the type of print object to which the pixel belongs, and the type of print object is classified into at least an image object and a non-image object. In this embodiment, an attribute value for identifying whether the object attribute is an image object or other than an image object is set as the attribute data.

  The memory access control unit 14 controls to sequentially send image data and attribute data from the image memory 12 and the attribute memory 13 in accordance with a command from the CPU 11.

  Each circuit included in the first color material reduction processing unit 15 and the second color material reduction processing unit 16 performs conversion on the received image data in accordance with the set parameters.

  Next, operations in the first saturation conversion circuit 151 and the second saturation conversion circuit 161 will be described with reference to FIGS. FIG. 2 is a diagram illustrating a saturation conversion algorithm, and FIG. 3 is a diagram for explaining saturation conversion. In FIG. 3, the vertical length of the bar graph indicates the density of each color component.

  Here, the chromatic color material CMY constitutes the saturation component of the print color. In the present embodiment, saturation conversion is performed by converting the CMY density while maintaining the K component.

  For example, a pixel having each density of CMYK as shown in FIG.

  First, as shown in FIG. 3B, the gray scale density GL when only the CMY components are converted to gray scale is calculated. CMY is regarded as a complementary color of RGB, and CMY gray scale density conversion formula (GL = (C × 5 + M × 9 + Y × 2) from a known RGB gray scale conversion formula (NTSC; Y = 0.299R + 0.587G + 0.114B) / 16) is derived. Here, each coefficient is approximated to n / 16. By approximating the coefficient to n / 16, division can be realized by bit shift, and a circuit can be realized with a simpler hardware configuration.

  Subsequently, as shown in FIG. 3B and FIG. 3C, the difference between the CMY color density and the gray scale density GL is corrected according to the saturation conversion rate (indicated as “Ratio” in FIG. 2). To do. Here, when each density of CMY is the same density GL, the density GL becomes gray. The gray scale density GL and the density difference between the respective colors are components constituting the saturation, and it is considered that the saturation is lowered when the gray scale density GL and the density difference between the respective colors are reduced. Further, by providing the saturation conversion rate in the form of n / 16, a circuit can be realized with a simpler hardware configuration.

  Next, operations in the first density conversion circuit 152 and the second density conversion circuit 162 will be described with reference to FIG. FIG. 4 is a diagram showing a density conversion algorithm.

  That is, as shown in FIG. 4, the density conversion is performed by multiplying each color density of CMYK before conversion by a density conversion rate (indicated by “Ratio” in FIG. 4).

  Next, operations in the first under color removal / black plate generation circuit 153 and the second under color removal / black plate generation circuit 163 will be described with reference to FIGS. FIG. 5 is a diagram showing an algorithm of under color removal / black plate generation (UCR (Under Color Removal) / BG (Black Generation)), and FIG. 6 is a diagram for explaining under color removal / black plate generation. . In FIG. 6, the vertical length of the bar graph indicates the density of each color component.

  For example, a pixel having each density of CMYK as shown in FIG. When each CMY density is the same density D, it can be regarded as equivalent to the density D gray.

  As shown in FIG. 6B, in the under color removal / black plate generation, in accordance with the above-described concept, the density value of the color with the lowest density among the CMY is partly or entirely the lower color component Du. Replaced with K version (black version). When a part Dr of the lower color component is replaced with the K plate (black plate), the density of each CMY color is reduced by Dr and the K density is increased by Dr. In this case, the color material to be used can be reduced by 3Dr−Dr = 2Dr. Here, of the lower color component Du, the ratio Dr / Du for replacement with the K plate (black plate) is the lower color removal ratio.

  Generally, when any density of CMY is 0, there is no lower color component, and it is not possible to realize reduction of the color material to be used by under color removal / black plate generation. However, in this embodiment, even if the density of any one of the original CMY is 0, the lower color component can be generated by performing the saturation conversion that reduces the saturation in the previous stage. Reduction of the color material to be used by removal / black plate generation is effective.

  In the present embodiment, the first selection circuit 17 selects and outputs the output data of the first color material reduction processing unit 15 when the pixel attribute data indicates an image object, and the pixel attribute data is an image. When indicating that the object is not an object, the output data of the second color material reduction processing unit 16 is selected and output.

  The print mode signal is a signal for designating the normal print mode or the color material reduction print mode. This print mode signal is set based on a user instruction through a menu or switch on an operation panel (not shown) of the color printing apparatus 1, or a mode designation command included in print data from a host computer (not shown) Is set according to

  The second selection circuit 18 selects and outputs the output data of the first selection circuit 17 when the print mode signal indicates the color material reduction print mode, and indicates that the print mode signal is the normal print mode. In the case shown, image data (pixel data) read from the image memory (not subjected to conversion for color material reduction) is selected and output.

  As already known, the realization of full color printing by superimposing images of two or more colors raises the consumption of color materials in color printing. In addition, the reduction of the color material consumption by the undercolor removal / black plate generation, in which the achromatic (gray) component generated by the superposition of the three color materials of CMY is replaced with the achromatic (black) color material, has already been partially It has been implemented in color printing. However, as described above, the under color removal / black plate generation alone is effective for reducing the color material consumption in the case of vivid (high chroma) colors that do not contain an achromatic color (gray) component in the background. I can't. This embodiment is based on the premise that it is not always necessary to accurately reproduce colors in printing applications that do not necessarily require high image quality, such as draft printing except for color proofing applications. ) Even if it is a “brilliant (highly saturated) color that does not contain any components”, it is possible to forcibly generate an achromatic (gray) component in the background by reducing the saturation, and to remove the undercolor / black plate The effect of reducing the material consumption is generated. The density conversion for reducing the density is an auxiliary means for realizing further reduction of the color material consumption, and is not necessarily essential.

  In this embodiment, when the color material reduction printing mode is designated, the first color material reduction processing unit 15 and the second color material reduction processing unit 16 perform “saturation reduction”, “density reduction (lightness improvement)”, “ By performing the conversion process of “under color removal / black plate generation”, the amount of color material consumed in printing can be reduced. In full-color printing that is not in the color material reduction printing mode, the color material consumption is particularly large for image objects such as photographs that contain a lot of halftones, and for objects other than image objects that are primarily monochromatic, the color is compared to the image object. It is known that the consumption of wood is low. Therefore, the color material reduction rate for image objects in the color material reduction printing mode is particularly large, and the color material reduction rate for objects other than image objects is set appropriately so that the visibility of characters is not significantly reduced. The consumption of coloring material can be reduced.

  In this embodiment, since the conversion process is performed using the result converted into the color material color (CMYK) used in the color printing apparatus 1, the print color is used in a versatile color space such as Postscript (registered trademark). Even when PDL (page description language) in which is specified is used, the color space (color space) to be converted can be uniquely fixed. Therefore, many data resources are not required.

  In full-color printing in which image objects such as photographs dominate, approximately 2.5 to 3 times as much toner is consumed as in grayscale printing. On the other hand, in character-based full color printing, approximately 1 to 2 times as much toner as in gray scale printing is consumed. Therefore, in the color material reduction process (first color material reduction processing unit 15) for the image object, the color material consumption amount is approximately 1/3, and the color material reduction process (second color material reduction processing unit 16) for the object other than the image. ), It is desirable to set the conversion parameter so that the color material consumption is approximately ½. In this way, it is possible to achieve almost the same amount of color material consumption as in gray scale printing. This has the effect of prompting the user to perform color printing without worrying too much about printing costs.

  According to the experiment, when the saturation conversion rate is 50%, the density conversion rate is 62.5%, the under color removal ratio is 100%, the color material consumption is approximately 1/3, the saturation conversion rate is 50%, and the density conversion rate. At 75.0% and under color removal ratio of 100%, the result was that the color material consumption was approximately halved. In this case, since the color component is not completely discarded by securing 50% as the saturation conversion rate, an effect of remaining an emphasis component such as a color character is obtained. In addition, since 70% is secured as the density conversion rate for the character object corresponding to the object other than the image, it is possible to suppress a decrease in character visibility.

  In the present embodiment, each parameter set in the first color material reduction processing unit 15 and the second color material reduction processing unit 16 is set in the first register 111 and the second register that can be directly referred to by the CPU 11. Has been. For this reason, it is possible to arbitrarily change the parameters in the control program, and it is also possible to set the parameter setting values through an operation panel unit (not shown) of the color printing apparatus 1.

  As described above, in the first embodiment, the second selection circuit 18 of the color printing apparatus 1 determines the color material color used in the color printing apparatus 1 when it is determined that the color material reduction printing mode is set. Saturation conversion that reduces saturation for each pixel of the converted bitmap, and undercolor removal that replaces at least a portion of the achromatic color component generated by superimposing a plurality of color materials with an achromatic color material / Outputs color material reduction processed data that has undergone color material reduction processing including black plate generation.

  Therefore, according to this embodiment, the present invention can be applied to printing without using a host computer without requiring many data resources to cope with various print data formats and color spaces, and the print image visibility can be improved. It is possible to reduce the color material consumption without drastically reducing it.

  In the present embodiment, the setting in the color material reduction process is set to be different for each type of print object. However, the present invention is not limited to this, and the same parameter may be set for all objects. . In addition, the types of print objects are classified into image objects and other objects, but the present invention is not limited to this. For example, image objects, graphics objects, and text objects are classified into more than two types. May be performed.

  Next, a second embodiment of the present invention will be described focusing on differences from the first embodiment. Note that description of points in common with the first embodiment will be omitted as appropriate.

  FIG. 7 is a block diagram showing a configuration of a color printing apparatus 1a to which a color printing control apparatus according to the second embodiment of the present invention is applied. A color printing apparatus 1a shown in FIG. 7 is an electrophotographic color printer that uses four color toners of CMYK. In the first embodiment, the function of executing the color material reduction process for reducing the color material consumption is configured by hardware, whereas in the second embodiment, the color material reduction process is executed. Both are different in that the function to be configured is software.

  The color printing apparatus 1a includes a CPU 11 that controls each unit in the color printing apparatus 1a and various arithmetic processes, a primary image memory 12 that stores image data obtained by analyzing input print data, and a primary image memory 12 An attribute memory 13 for storing attribute data of an object to which each pixel (pixel) of the image data developed in the image belongs, a data receiving circuit 21 for receiving print data, and a work for temporarily storing programs and data as a work area Memory (RAM) 22, program / resource memory (ROM) 23 for storing various programs and various data, output image memory 24 for storing output image data for image formation, and printing based on the output image data An image forming circuit 20 to be controlled is included.

  The data receiving circuit 21 is a LAN card used for communicating with an external device via a network, for example, and uses standards such as Ethernet (registered trademark), token ring, and FDDI. However, the color printing apparatus 1a may be connected to an external device by local connection. For local connection, various local connection interfaces such as serial interfaces such as USB and IEEE1394, parallel interfaces such as SCSI and IEEE1284, and wireless communication interfaces such as Bluetooth (registered trademark), IEEE802.11, HomeRF, and IrDA are used.

  In FIG. 7, the components of the color printing apparatus 1 a that are mainly related to the present invention are described, and the color printing apparatus 1 a may include components other than the above-described components, or Some of the above-described components may not be included.

  Next, processing in the color printing apparatus 1a will be described with reference to FIGS. 8 and 9 is stored as a program in a storage unit such as the program / resource memory (ROM) 23 of the color printing apparatus 1a, and the CPU 11 stores the algorithm on the work memory (RAM) 22. Executed.

  First, the color printing device 1a receives print data from the host device (host computer) such as a PC (personal computer) outside the color printing device 1a via the printer interface (not shown) (S101). .

  The CPU 11 analyzes the input print data (S102). Then, according to the print data, the CPU 11 stores (printed) image data of 32-bit (8 bits × 4 colors) data converted into CMYK, which is a color material color used in the color printing apparatus 1a, in the primary image memory 12. Expand (S103). Further, the CPU 11 sets attribute data indicating the attribute of each pixel of the image data expanded in the image memory 12 in the attribute memory 13 (S103). The attribute includes the type of print object to which the pixel belongs, and the type of print object is classified into at least an image object and a non-image object. In this embodiment, an attribute value for identifying whether the object attribute is an image object or other than an image object is set as the attribute data.

  After the expansion of the data to the primary image memory 12 and the attribute memory 13 is completed, the CPU 11 reads the image data and the attribute data for each pixel (pixel) into the work memory 22 (S104).

  In step S105, it is determined whether or not the color material reduction printing mode is designated. That is, it is determined whether or not the color material reduction print mode is specified in the received print data. However, the color material reduction printing mode may be specified based on a user instruction through a menu or switch on an operation panel (not shown) of the color printing apparatus 1a. If it is determined that the color material reduction printing mode is not designated (S105: NO), the process proceeds to step S107.

  If it is determined that the color material reduction printing mode is designated (S105: YES), color material reduction processing is executed (S106).

  As shown in FIG. 9, in the color material reduction process, each conversion process of saturation conversion, density conversion, and under color removal / black plate generation is sequentially executed. The algorithm of each conversion process is the saturation conversion (see FIGS. 2 and 3), density conversion (see FIG. 4), under color removal / black plate generation (see FIGS. 5 and 6) shown in the first embodiment. It is the same as the algorithm.

  First, pixel attribute data is referred to, and it is determined whether or not the pixel attribute is an image object (S201).

  When it is determined that the pixel attribute is an image object (S201: YES), the first saturation conversion (S202), the first density conversion (S203), and the first undercolor removal / black plate generation (S204) are performed. It is done sequentially. Here, in the first saturation conversion (S202), the first density conversion (S203), and the first undercolor removal / black plate generation (S204), the first saturation conversion circuit 151 of the first embodiment, respectively. The same processing as that performed in the first density conversion circuit 152 and the first undercolor removal / black plate generation circuit 153 is performed.

  On the other hand, when it is determined that the pixel attribute is an object other than the image object (S201: NO), the second saturation conversion (S205), the second density conversion (S206), and the second under color removal / black plate Generation (S207) is performed sequentially. Here, in the second saturation conversion (S205), the second density conversion (S206), and the second undercolor removal / black plate generation (S207), the second saturation conversion circuit 161 of the first embodiment, respectively. The same processing as that performed by the second density conversion circuit 162 and the second undercolor removal / black plate generation circuit 163 is performed.

  Thus, the color material reduction process (conversion process) can be executed with different parameters depending on whether the pixel attribute is an image object or a non-image object.

  When the color material reduction print mode is designated, the result after the color material reduction process is input, and when the color material reduction print mode is not designated, the pixel data read from the primary image memory 12 is obtained. As an input, a screening process is executed (S107). Subsequently, the result after the screening process is written in the output image memory 24 (S108).

In step S109, it is determined whether the screening process has been completed up to the final pixel (pixel). When the screening process has not been completed up to the final pixel (S109: NO), the process returns to step S104. When it is determined that the screening process has been completed up to the final pixel (S109: YES), the CPU 11 activates the image forming circuit 20 ( S110). The image forming circuit 20 reads pixel data from the output image memory 24 and executes printing.

  As described above, according to the second embodiment, similarly to the first embodiment, the host computer is not required without requiring many data resources for supporting various print data formats and color spaces. The present invention can be applied to printing that is not performed, and it is possible to reduce the amount of color material consumed without significantly reducing the visibility of a printed image.

  Next, a third embodiment of the present invention will be described focusing on differences from the second embodiment. Note that description of points in common with the second embodiment will be omitted as appropriate.

  FIG. 10 is a block diagram showing a configuration of a color printing apparatus 1b to which the color printing control apparatus according to the third embodiment of the present invention is applied. A color printing apparatus 1b shown in FIG. 10 is an electrophotographic color printer that uses four color toners of CMYK. In the second embodiment, the color material reduction process is performed on each pixel of the bitmap converted to the color material color used in the color printing apparatus, whereas in the third embodiment, the color printing apparatus Is different in that the color data input to the color data is converted into the color material color used in the color printing apparatus using the color material reduction color conversion profile capable of simultaneously executing the color material reduction processing. .

  The color printing apparatus 1b includes a CPU 11 that controls each unit in the color printing apparatus 1b and various arithmetic processes, a data receiving circuit 21 that receives print data, and a work memory (RAM) that temporarily stores programs and data as work areas. 22, a program / resource memory (ROM) 23 for storing various programs and various data, an output image memory 24 for storing output image data for image formation, and an image forming circuit 20 for performing print control based on the output image data have.

  Note that FIG. 10 illustrates components of the color printing apparatus 1b that are mainly related to the present invention, and the color printing apparatus 1b may include components other than the above-described components. Some of the above-described components may not be included.

  Next, processing in the color printing apparatus 1b will be described with reference to FIGS. The algorithm shown in the flowcharts of FIGS. 11 and 12 is stored as a program in a storage unit such as the program / resource memory (ROM) 23 of the color printing apparatus 1b, and is stored on the work memory (RAM) 22 by the CPU 11. Executed.

  First, the color printing apparatus 1b receives print data from the host device (host computer) such as a PC (personal computer) outside the color printing apparatus 1b via the printer interface (not shown) (S301). .

  The CPU 11 analyzes the input print data (S302). Then, in accordance with the print data, the CPU 11 develops (print) image data of 32 bit (8 bit × 4 color) data converted into CMYK, which is a color material color used in the color printing apparatus 1b, in the output image memory 24. (S303).

  Here, when converting the color of the print object in the print data input to the data receiving circuit 21 to the color material color CMYK of the color printing apparatus 1b, the CPU 11 performs color conversion processing using the color profile of the color printing apparatus 1b. I do.

  In this embodiment, as shown in FIG. 12, in the color conversion process, it is first determined whether or not the color material reduction printing mode is designated (S401). That is, it is determined whether or not the color material reduction print mode is specified in the received print data. However, the color material reduction printing mode may be specified based on a user instruction through a menu or switch on an operation panel (not shown) of the color printing apparatus 1b.

  If it is determined that the color material reduction printing mode is not designated (S401: NO), the process proceeds to step S402, and the normal profile is read into the work memory 22.

  On the other hand, when it is determined that the color material reduction printing mode is designated (S401: YES), it is determined whether or not the attribute is an image object (S403). When it is determined that the attribute is an image object (S403: YES), the first profile is read into the work memory 22 (S404), and when it is determined that the attribute is an object other than the image object (S403: NO). The second profile is read into the work memory 22 (S405).

  Here, the first profile is a color conversion profile adjusted for the image object color material reduction printing mode, and the first saturation conversion circuit 151, the first density conversion circuit 152, and the first density conversion circuit of the first embodiment. This is a profile for executing processing similar to that performed by the under color removal / black plate generation circuit 153 simultaneously with color conversion. The second profile is a color conversion profile adjusted for the object color material reduction printing mode other than the image object, and the second saturation conversion circuit 161, the second density conversion circuit 162, and the second density conversion circuit 162 of the first embodiment. This is a profile for executing processing similar to that performed by the second undercolor removal / black plate generation circuit 163 simultaneously with color conversion.

  Then, the color data input to the color printing apparatus 1b is color-converted to CMYK, which is the color material color of the color printing apparatus 1b, using the profile read into the work memory 22 (S406).

  In this way, it is possible to execute color conversion accompanied by color material reduction processing with different parameters depending on whether the attribute is an image object or an image object. Note that the processing shown in FIG. 12 is desirably executed for each object.

  Returning to the flowchart of FIG. 11, in step S <b> 304, screening processing is performed on the image data that has undergone color conversion. Subsequently, the result after the screening process is written in the output image memory 24 (S305).

  After the screening process is completed, the CPU 11 activates the image forming circuit 20 (S306). The image forming circuit 20 reads pixel data from the output image memory 24 and executes printing.

  In the present embodiment, a first profile and a second profile are prepared as color conversion profiles. Then, the first profile and the second profile are adjusted so that the same result as that obtained by pixel conversion by the algorithm shown in the first embodiment is obtained. Here, an ICC (International Color Consortium) color profile is used as the color conversion profile. If the pixel conversion parameters for the normal printing mode are determined, the color conversion profiles (first profile and second profile) for the color material reduction printing mode can be easily created from the color conversion profiles for the normal printing mode. is there. That is, many of the color conversion profiles for the printing apparatus use a three-dimensional lookup table called CLUT. Therefore, the color conversion profile for the color material reduction printing mode is a CMYK output value in each grid in the lookup table. Can be easily created by replacing according to pixel conversion parameters and conversion algorithm.

  As described above, the third embodiment also requires a large amount of data resources to support various print data formats and color spaces, as in the first and second embodiments. In addition, the present invention can be applied to printing not via a host computer, and the consumption of color materials can be reduced without extremely reducing the visibility of a printed image. In addition, since the color material reduction process and the color conversion process are performed at the same time, the process in the color material reduction print mode can be speeded up.

  Next, a fourth embodiment of the present invention will be described focusing on differences from the first embodiment. Note that description of points in common with the first embodiment will be omitted as appropriate.

  In the first embodiment, a saturation conversion rate indicating a ratio of saturation after conversion with respect to saturation before conversion, and a density conversion rate indicating a ratio of density after conversion with respect to density before conversion are set in advance as parameters. Is done. On the other hand, in the fourth embodiment, in the saturation conversion, the saturation conversion rate is set for each pixel in accordance with the saturation of the pixel to be processed. In the fourth embodiment, in the density conversion, the density conversion rate is set for each pixel according to the density of the pixel to be processed.

  FIG. 13 is a block diagram showing a configuration of a color printing apparatus 1c to which a color printing control apparatus according to the fourth embodiment of the present invention is applied.

  The color printing apparatus 1c is developed in a CPU 11 that controls each part in the color printing apparatus 1c and various arithmetic processes, an image memory 12 that stores (printing) image data obtained by analyzing input print data, and an image memory The attribute memory 13 for storing the attribute data of the object to which each pixel of the image data being assigned belongs, the memory access control unit 14 for sequentially sending the image data and the attribute data from the image memory 12 and the attribute memory 13, respectively, Output data of the first color material reduction processing unit 15a, the second color material reduction processing unit 16a, the first color material reduction processing unit 15a, or the output data of the second color material reduction processing unit 16a for reducing the consumption of the material Is selected from the image memory according to the attribute data. An image can be formed by using the second selection circuit 18 for selecting either the output image data (pixel data) or the output data of the first selection circuit 17 according to the print mode signal, and a gradation reproduction method such as a dither method. A screening processing unit 19 that generates correct image data, and an image forming circuit 20 that performs print control based on the sent image data.

  The first color material reduction processing unit 15a and the second color material reduction processing unit 16a are functional blocks that independently convert the CMYK density of the image data. The first color material reduction processing unit 15a and the second color material reduction processing unit 16a have different processing contents as will be described later.

  The first color material reduction processing unit 15a includes a first saturation conversion circuit 31, a first undercolor removal / black plate generation circuit 32, and a first density conversion circuit 33, and a second color material reduction processing unit 16a. Includes a second saturation conversion circuit 41, a second undercolor removal / black plate generation circuit 42, and a second density conversion circuit 43. Here, the first saturation conversion circuit 31 and the second saturation conversion circuit 41 are circuits for reducing the saturation, and the first under color removal / black plate generation circuit 32 and the second under color removal / black plate. The generation circuit 42 is a circuit for replacing at least a part of the achromatic color component generated by superimposing a plurality of color materials with an achromatic color material, and the first density conversion circuit 33 and the second density conversion circuit 43 have the density. It is a circuit for reducing.

  In FIG. 13, the components of the color printing apparatus 1 c that are mainly related to the present invention are described, and the color printing apparatus 1 c may include components other than the above-described components, or Some of the above-described components may not be included.

  Next, the operation of the color printing apparatus 1c configured as described above will be described.

  Here, the color printing apparatus 1c includes a color material reduction printing mode for printing while reducing the color material consumption.

  The CPU 11 analyzes the print data input to the data receiving circuit via a printer interface (not shown), and converts the color data into CMYK, which is a color material color used in the color printing apparatus 1, in the image memory 12 according to the print data. The image data of 32 bits (8 bits × 4 colors) data is developed. Further, the CPU 11 sets attribute data indicating the attribute of each pixel of the image data developed in the image memory 12 in the attribute memory 13. The attribute includes the type of print object to which the pixel belongs, and the type of print object is classified into at least an image object and a non-image object. In this embodiment, an attribute value for identifying whether the object attribute is an image object or other than an image object is set as the attribute data.

  The memory access control unit 14 controls to sequentially send image data and attribute data from the image memory 12 and the attribute memory 13 in accordance with a command from the CPU 11.

  Each circuit included in the first color material reduction processing unit 15a and the second color material reduction processing unit 16a performs conversion on the received image data.

  Next, operations in the first saturation conversion circuit 31 and the second saturation conversion circuit 41 will be described with reference to FIGS. FIG. 14 is a diagram illustrating a configuration of the first saturation conversion circuit 31 and the second saturation conversion circuit 41, and FIG. 15 is a diagram illustrating an algorithm of saturation conversion.

  As shown in FIG. 14, the gray scale density calculation unit 311 is a circuit that calculates the gray scale density GL when only the input CMY (chromatic color) components are converted to gray scale.

  The saturation calculation unit 312 is a circuit that calculates the saturation S of the input pixel.

  The saturation conversion rate table 314 is a lookup table (LUT) for acquiring saturation conversion rate calculation data Rs corresponding to the saturation S of the input pixel (see FIG. 24), and is configured by a RAM. The RAM constituting the LUT 314 is connected to the CPU bus via the access control unit 313. Thereby, the saturation conversion rate table 314 can be set arbitrarily.

  The saturation conversion unit 315 performs saturation conversion by referring to the gray scale density GL and the saturation conversion rate calculation data Rs and converting the density of the CMY (chromatic color) component. That is, the saturation conversion is performed by converting the CMY density while maintaining the K component.

  Specifically, the gray scale density GL is calculated by the equation shown in FIG. Here, CMY is regarded as a complementary color of RGB, and the CMY gray scale density conversion formula (GL = (C × 5 + M × 9 + Y) is converted from the known RGB gray scale conversion formula (NTSC; Y = 0.299R + 0.587G + 0.114B). X2) / 16) is derived.

  Specifically, the saturation S is calculated by the equation shown in FIG. Here, MaxValue (X, Y) is a function that returns the larger value of X and Y, and MinValue (X, Y) is a function that returns the smaller value of X and Y.

The calculated saturation S of the pixel does not necessarily have to be saturation defined in various color spaces such as HSL, Ycc, L ^* a ^* b ^* , and may be an index value indicating the level of saturation. . In the present embodiment, the saturation index value is calculated by regarding that the saturation component constituted by the maximum density difference of the CMY (chromatic color) component is reduced by (K density component + lower color component of CMY). The As a result, the saturation is reduced by the saturation conversion. In this embodiment, the saturation conversion rate is set for each pixel in accordance with the saturation of the pixel to be processed. For this reason, the saturation S (index value) is calculated more accurately than in the first embodiment by the calculation formula shown in FIG.

  Saturation conversion is specifically performed by the equation shown in FIG. That is, the CMY density is converted while the K component is maintained with reference to the gray scale density GL and the saturation conversion rate calculation data Rs.

  In the present embodiment, in the saturation conversion, a saturation conversion rate is set for each pixel according to the saturation of the pixel to be processed. Specifically, the saturation conversion rate for the first pixel is set larger than the saturation conversion rate for the second pixel having a lower saturation than the first pixel. In other words, the degree of reducing the saturation of the first pixel is set smaller than the degree of reducing the saturation of the second pixel having a lower saturation than that of the first pixel.

  In the present embodiment, the RAM constituting the saturation conversion rate table (LUT) 314 is an 8-bit RAM. The output value set in the LUT 314 is the saturation conversion rate calculation data Rs. Here, when the saturation conversion rate calculation data Rs (output value) is “128”, the saturation conversion rate is 100%. Further, when the saturation conversion rate calculation data Rs (output value) is “64”, the saturation conversion rate is 50% (see FIG. 24). That is, the saturation conversion rate is given by Rs / 128 (%).

  As described above, in the saturation conversion in the present embodiment, the saturation component constituted by the maximum density difference of the CMY (chromatic color) components is output from the saturation conversion rate table 314 for the saturation conversion rate calculation data. Conversion is performed according to Rs. In the calculation of the saturation, the saturation (saturation index value) is regarded as “the saturation component constituted by the maximum density difference of the CMY (chromatic color) component is reduced by the CMY lower color component + K density”. Calculated. However, in the saturation conversion, in order to simplify the calculation, only the saturation component constituted by the maximum density difference of the CMY (chromatic color) components is to be converted.

  Next, operations in the first undercolor removal / black plate generation circuit 32 and the second undercolor removal / black plate generation circuit 42 will be described with reference to FIGS. FIG. 16 is a diagram showing the configuration of the first under color removal / black plate generation circuit 32 and the second under color removal / black plate generation circuit 42, and FIG. 17 is a diagram showing the under color removal / black plate generation algorithm. is there.

  As shown in FIG. 16, the minimum density value acquisition unit 321 is a circuit that acquires the minimum density value of the input CMY (chromatic color) component. Here, the minimum density value represents the lower color component D of the CMY (chromatic color) component.

  The removal amount table 323 is a lookup table (LUT) for acquiring a lower color removal amount U corresponding to the lower color component D of the input pixel (see FIG. 24), and is configured by a RAM. The RAM constituting the LUT 323 is connected to the CPU bus via the access control unit 322. Thereby, the removal amount table 323 can be set arbitrarily.

  The under color removal unit 324 decrements each density of the input CMY (chromatic color) component by the under color removal amount U.

  The generation amount table 326 is a lookup table (LUT) for acquiring the black plate generation amount B corresponding to the lower color component D of the input pixel (see FIG. 24), and is configured by a RAM. The RAM constituting the LUT 326 is connected to the CPU bus via the access control unit 325. Thereby, the generation amount table 326 can be set arbitrarily.

  The black plate generation unit 327 increases the density of the input K (achromatic) component by the black plate generation amount B.

  Specifically, the calculation of the minimum density value D, the removal of the under color, and the black plate generation are performed by equations shown in FIG.

  In this embodiment, the RAM constituting the removal amount table (LUT) 323 and the generation amount table (LUT) 326 is an 8-bit RAM. In the LUTs 323 and 326, a lower color removal amount U and a black plate generation amount B corresponding to the lower color component D are directly set.

  Next, operations in the first density conversion circuit 33 and the second density conversion circuit 43 will be described with reference to FIGS. 18 is a diagram showing the configuration of the first density conversion circuit 33 and the second density conversion circuit 43, and FIG. 19 is a diagram showing an algorithm for density conversion.

  As illustrated in FIG. 18, the maximum density value acquisition unit 331 is a circuit that acquires the maximum density value M of the input CMYK (color material) components.

  The density conversion rate table 333 is a lookup table (LUT) for acquiring density conversion rate calculation data Rd corresponding to the maximum density value M of the input pixel (see FIG. 24), and is configured by a RAM. The RAM constituting the LUT 333 is connected to the CPU bus via the access control unit 332. Thereby, the density conversion rate table 333 can be set arbitrarily.

  The density conversion unit 334 converts the density of CMYK (color material) components based on the density conversion rate calculation data Rd.

  Specifically, the calculation of the maximum density value M and the density conversion are respectively performed by equations shown in FIG.

  In the present embodiment, in the density conversion, a density conversion rate is set for each pixel according to the density of the pixel to be processed. Specifically, the density conversion rate for the first pixel is set larger than the density conversion rate for the second pixel having a lower density than the first pixel. In other words, the degree of reducing the density of the first pixel is set smaller than the degree of reducing the density of the second pixel having a lower density than the first pixel.

  In the present embodiment, the RAM constituting the density conversion rate table 333 is an 8-bit RAM. The output value set in the LUT 333 is density conversion rate calculation data Rd. Here, when the density conversion rate calculation data Rd (output value) is “128”, the density conversion rate is 100%. Further, when the density conversion rate calculation data Rd (output value) is “64”, the density conversion rate is 50% (see FIG. 24). That is, the density conversion rate is given by Rd / 128 (%).

  In the present embodiment, the first selection circuit 17 selects and outputs the output data of the first color material reduction processing unit 15a when the pixel attribute data indicates an image object, and the pixel attribute data is an image. When indicating that the object is not an object, the output data of the second color material reduction processing unit 16a is selected and output.

  The second selection circuit 18 selects and outputs the output data of the first selection circuit 17 when the print mode signal indicates the color material reduction print mode, and indicates that the print mode signal is the normal print mode. In the case shown, image data (pixel data) read from the image memory (not subjected to conversion for color material reduction) is selected and output.

  Next, the effect of color material reduction by saturation conversion and under color removal / black plate generation will be described with reference to FIGS. 20 and 21. FIG. 20 and FIG. 21, the length of the bar graph indicates the density of each color component. 20 and 21, the concentration is given as a percentage, and the concentration of 100% corresponds to “255” when the concentration is expressed by a numerical value of 8 bits (the same applies to the concentration in FIG. 23).

  FIG. 20A is a diagram illustrating an example of CMYK density of an input pixel, and FIG. 20B is a diagram illustrating a saturation conversion result. In the example shown in FIG. 20A, the gray scale density GL of the CMY component is 50%, and the saturation component SCmy configured by the maximum density difference of the CMY (chromatic color) component is 75%. Then, the saturation (saturation index value) calculated by regarding that the saturation component Scmy is reduced by (CMY lower color component + K density) is 46.5%.

  FIG. 20B shows a case where the saturation conversion rate corresponding to the saturation (saturation index value) 46.5% calculated from the combination of CMYK densities of the input pixels in FIG. 20A is 50%. The saturation conversion result is shown. The difference of each CMY density from the gray scale density GL of the CMY component is reduced based on the saturation conversion rate (here, 50%). Here, the saturation component Scmy configured by the maximum density difference of the CMY components decreases by an amount corresponding to the saturation conversion rate, and becomes 38%.

  By reducing the saturation component constituted by the maximum density difference of the CMY components, the undercolor component described below increases. Thereby, the effect of color material reduction by under color removal becomes large.

  FIG. 21A is a diagram for explaining the lower color component and the lower color removal amount in the saturation conversion result shown in FIG. 20B, and FIG. 21B is the lower color removal / black plate generation. It is a figure which shows the result of having performed.

  In FIG. 21A, the lower color component Du is 38%, and the lower color removal amount Dr is 25% as an example. FIG. 21B shows a conversion result when the under color removal / black plate generation is performed with the black plate generation amount equal to the under color removal amount Dr with respect to FIG. Here, the total density value obtained by adding the CMYK density values in FIG. 21 (b) is equal to the total amount of density values in FIG. Reduced. That is, the color material to be used can be reduced. FIG. 21 shows an example in which the under color removal amount is smaller than the under color component (under color removal ratio is less than 100%). However, the effect of reducing the color material consumption is the greatest when the under color removal ratio is 100%.

  Next, the effect of the combination of saturation conversion and under color removal / black plate generation will be described.

  In the present embodiment, it is possible to reduce the color material consumption while maintaining the saturation of high saturation color suitable for color document proofing as much as possible. For this reason, the degree of reduction in saturation is set to be small (the saturation conversion rate is increased) with respect to a highly saturated color such as red, which is used as an emphasis point in many color documents.

  On the other hand, the degree of reduction in saturation is set to be large (the saturation conversion rate is small) for the low saturation part. As a result, in the low saturation portion, as a result of the saturation conversion, the increase amount of the lower color component described above increases, and the effect of reducing the color material consumption by the saturation conversion and the lower color removal / black plate generation increases. That is, the color material consumption reduction effect is greater than when only under color removal / black plate generation is performed.

  Next, the effect of color material reduction by density conversion will be described with reference to FIG. 22 and FIG. Density conversion is an auxiliary means for realizing further reduction in color material consumption.

  In general, in an electrophotographic color printer, it is difficult to express light and shade by a single pixel to be printed. Therefore, by performing binarization processing such as dither screen and error diffusion on the image data, shades are expressed in the print image.

  FIG. 22 is a diagram illustrating an example of a dot pattern for light and shade expression using a dither screen. The numerical values described in FIG. 22 represent the rate at which dots per unit area are placed. Here, the ratio of dots placed per unit area is expressed as “dot coverage”.

  In actual printing, the size of dots to be printed is set to be larger than the pixel pitch at the printing resolution in consideration of print image quality and stability. Therefore, the dot rate does not become the density of the printed image as it is. On the other hand, the dot rate is substantially proportional to the color material consumption.

  FIG. 23 is a diagram illustrating the relationship between the print image density and the dot rate.

  From FIG. 23, it can be seen that in the high density portion, a small reduction in printing density results in a large reduction in dot rate. For example, by reducing the printing density from 100% to about 10%, the dot rate is halved from 100% to about 50%, and a great effect of reducing the color material consumption can be obtained. On the other hand, in the low density portion, the dot rate change amount with respect to the density change amount is small. For example, unless the printing density is reduced from 40% to about 20%, the dot rate is not halved. A high saturation color such as black (black characters) most frequently used in text printing or red used as an emphasis point in a color document has a component of either CMYK having a density of 100% or a high density close thereto. Therefore, a large color material consumption reduction effect can be obtained by slightly reducing the printing density.

  In the present embodiment, the density of the color component having the highest density among the color components of the input pixel is acquired as the representative density. The degree of reducing the density for a pixel with a high representative density is set smaller than the degree of reducing the density for a pixel with a low representative density. As a result, a large color material consumption reduction effect can be obtained while suppressing a decrease in the visibility of high-saturation colors such as black (black characters) that are most frequently used in text printing, or red that is used for highlighting in color documents. Can do.

  FIG. 24 is a diagram for explaining an example of data set in the saturation conversion rate table, the removal amount table, the generation amount table, and the density conversion rate table.

  In FIG. 24, the saturation conversion rate calculation data Rs corresponding to the saturation (saturation index value) S of the input pixel, the undercolor removal amount U corresponding to the lower color component D of the input pixel, and the lower color of the input pixel. An example of the black generation amount B corresponding to the component D and an example of density conversion rate calculation data Rd corresponding to the maximum density value M of the input pixel is shown.

  The test chart defined in ISO / IEC 24712: 2006 “Color test pages for measurement of office equipment consumable yield” is used in the color material reduction printing mode using each lookup table in which data shown in FIG. 24 is set. The toner consumption when printing was 44.5% with respect to the toner consumption when printing in the normal printing (no color material reduction) mode. In addition, 216 color patches (RGB 216 color patches) represented by combinations of 0%, 20%, 40%, 60%, 80%, and 100% of each color of red (R), green (G), and blue (B) ) Is printed in the color material reduction printing mode using each lookup table in which the data shown in FIG. 24 is set, the toner consumption amount is the toner when printing in the normal printing (no color material reduction) mode. It was 43.6% with respect to consumption. As described above, in any case, the toner consumption in the color material reduction printing mode is halved as compared with the normal printing mode.

  As already known, the realization of full color printing by superimposing images of two or more colors raises the consumption of color materials in color printing. In addition, the reduction of the color material consumption by the undercolor removal / black plate generation, in which the achromatic (gray) component generated by the superposition of the three color materials of CMY is replaced with the achromatic (black) color material, has already been partially It has been implemented in color printing. However, as described above, the effect of reducing the color material consumption cannot be obtained only by under color removal / black plate generation.

  In the present embodiment, when the color material reduction printing mode is designated, the first color material reduction processing unit 15a and the second color material reduction processing unit 16a perform “saturation reduction”, “under color removal / black plate generation”, By performing the conversion process of “density reduction (brightness improvement)”, the amount of color material consumed in printing can be reduced.

  In the present embodiment, various conversion parameters are obtained by referring to a lookup table. However, the present invention is not limited to this, and various conversion parameters using mathematical expressions are used. May be configured to calculate.

  As described above, in the fourth embodiment, in the saturation conversion, the saturation conversion rate is set for each pixel in accordance with the saturation of the pixel to be processed. Specifically, the saturation conversion rate for the first pixel is set larger than the saturation conversion rate for the second pixel having a lower saturation than the first pixel.

  Therefore, according to the fourth embodiment, in addition to being able to achieve the same effects as the first embodiment, it is possible to reduce the color material consumption while maintaining the saturation of the high chroma color as much as possible. It becomes possible. As a result, it is possible to obtain an operational effect that it is possible to suppress dullness of a highly saturated color such as red used in an emphasis portion in many color documents.

  In the fourth embodiment, in the density conversion, the density conversion rate is set for each pixel according to the density of the pixel to be processed. Specifically, the density conversion rate for the first pixel is set larger than the density conversion rate for the second pixel having a lower density than the first pixel.

  Here, high saturation colors such as black (black characters) that are most frequently used in text printing or red that are used for highlighting in color documents are high in density. In high density areas, a large color material can be obtained by reducing the density slightly. It has been found that the effect of reducing consumption can be obtained.

  Therefore, according to the fourth embodiment, black (black characters) most frequently used in text printing, or red, which is used as an emphasized part in a color document, is prevented from being deteriorated in visibility. The effect that a large color material consumption reduction effect can be obtained can be achieved.

  Next, a fifth embodiment of the present invention will be described focusing on differences from the second and fourth embodiments. Note that description of points in common with the second and fourth embodiments will be omitted as appropriate.

  FIG. 25 is a block diagram showing a configuration of a color printing apparatus 1d to which a color printing control apparatus according to the fifth embodiment of the present invention is applied.

  In the fourth embodiment, the function of executing the color material reduction process for reducing the color material consumption is configured by hardware, whereas in the fifth embodiment, the color material reduction process is executed. Both are different in that the function to be configured is software.

  The color printing apparatus 1d includes a CPU 11 that controls each part in the color printing apparatus 1d and various arithmetic processes, a primary image memory 12 that stores image data obtained by analyzing input print data, and a primary image memory 12 An attribute memory 13 for storing attribute data of an object to which each pixel (pixel) of the image data developed in the image belongs, a data receiving circuit 21 for receiving print data, and a work for temporarily storing programs and data as a work area Memory (RAM) 22, program / resource memory (ROM) 23 for storing various programs and various data, output image memory 24 for storing output image data for image formation, and printing based on the output image data An image forming circuit 20 to be controlled is included.

  In FIG. 25, the components of the color printing apparatus 1d that are mainly related to the present invention are described, and the color printing apparatus 1d may include components other than the above-described components. Some of the above-described components may not be included.

  Next, processing in the color printing apparatus 1d will be described with reference to FIGS. The algorithm shown in the flowcharts of FIGS. 26 to 30 is stored as a program in a storage unit such as the program / resource memory (ROM) 23 of the color printing apparatus 1d, and is executed on the work memory (RAM) 22 by the CPU 11. Executed.

  The description of steps S501 to S510 in FIG. 26 is the same as the description of steps S101 to S110 in FIG.

  When it is determined that the color material reduction printing mode is designated (S505: YES), a color material reduction process is executed (S506).

  As shown in FIG. 27, in the color material reduction process (S506), each conversion process of saturation conversion, undercolor removal / black plate generation, and density conversion is sequentially executed.

  In the color material reduction process (S506), first, pixel attribute data is referred to, and it is determined whether or not the attribute of the pixel is an image object (S601).

  When it is determined that the pixel attribute is an image object (S601: YES), the first saturation conversion (S602), the first undercolor removal / black plate generation (S603), and the first density conversion (S604) are performed. It is done sequentially.

  On the other hand, when it is determined that the pixel attribute is an object other than the image object (S601: NO), the second saturation conversion (S605), the second undercolor removal / black plate generation (S606), and the second density Conversion (S607) is sequentially performed.

  FIG. 28 is a flowchart showing the procedure of the first saturation conversion (S602) and the second saturation conversion (S605).

  As shown in FIG. 28, in the saturation conversion, first, the grayscale density GL when only the input CMY (chromatic color) component is converted to grayscale is calculated (S701), and then the input pixel is converted. The saturation S is calculated (S702). Subsequently, saturation conversion rate calculation data Rs corresponding to the saturation S of the input pixel is acquired (S703). Then, with reference to the gray scale density GL and the saturation conversion rate calculation data Rs, the saturation conversion is performed by converting the density of the CMY (chromatic color) component (S704).

  In the present embodiment, the saturation conversion rate table 314 that is a lookup table (LUT) for acquiring the saturation conversion rate calculation data Rs according to the saturation S of the input pixel is a program / resource memory (ROM). 23.

  Here, the algorithms of the first saturation conversion (S602) and the second saturation conversion (S605) are respectively performed by the first saturation conversion circuit 31 and the second saturation conversion circuit 41 of the fourth embodiment. This is the same as the processing algorithm (see FIGS. 14 and 15).

  FIG. 29 is a flowchart showing procedures of first undercolor removal / black plate generation (S603) and second undercolor removal / black plate generation (S606).

  As shown in FIG. 29, in under color removal / black plate generation, first, the minimum density value (under color component) D of the input CMY (chromatic color) component is acquired (S801). Subsequently, an under color removal amount U corresponding to the under color component D of the input pixel is acquired (S802). Then, under color removal is performed by reducing the density of each input CMY (chromatic color) component by the under color removal amount U (S803).

  Subsequently, a black generation amount B corresponding to the lower color component D of the input pixel is acquired (S804). Then, black generation is performed to increase the density of the input K (achromatic) component by the black generation amount B (S805).

  In the present embodiment, a removal amount table 323 that is a look-up table (LUT) for acquiring a lower color removal amount U corresponding to the lower color component D of the input pixel, and a black ink corresponding to the lower color component D of the input pixel. A generation amount table 326 that is a lookup table (LUT) for acquiring the plate generation amount B is stored in the program / resource memory (ROM) 23.

  Here, the first under color removal / black plate generation (S603) and second under color removal / black plate generation (S606) algorithms are respectively the first under color removal / black plate generation circuit of the fourth embodiment. 32 and the second undercolor removal / black plate generation circuit 42 (see FIGS. 16 and 17).

  FIG. 30 is a flowchart showing procedures of the first density conversion (S604) and the second density conversion (S607).

  As shown in FIG. 30, in the density conversion, first, the maximum density value M of the input CMYK (color material) components is acquired (S901). Subsequently, density conversion rate calculation data Rd corresponding to the maximum density value M of the input pixel is acquired (S902). Based on the density conversion rate calculation data Rd, the density of the CMYK (coloring material) component is converted (S903).

  In the present embodiment, the density conversion rate table 333 that is a lookup table (LUT) for acquiring the density conversion rate calculation data Rd corresponding to the maximum density value M of the input pixel is the program / resource memory (ROM) 23. Is saved.

  Here, the algorithms of the first density conversion (S604) and the second density conversion (S607) are the algorithms of the processes performed in the first density conversion circuit 33 and the second density conversion circuit 43 of the fourth embodiment, respectively. It is the same (refer FIG. 18 and FIG. 19).

  In this embodiment, various conversion parameters are acquired by referring to a lookup table. However, the present invention is not limited to this, and various conversion parameters can be obtained using mathematical expressions. May be configured to calculate.

  As described above, according to the fifth embodiment, it is possible to achieve the same operational effects as those of the fourth embodiment.

  Next, a sixth embodiment of the present invention will be described focusing on differences from the third and fifth embodiments. Note that description of points common to the third and fifth embodiments will be omitted as appropriate.

  FIG. 31 is a block diagram showing a configuration of a color printing apparatus 1e to which a color printing control apparatus according to the sixth embodiment of the present invention is applied.

  In the fifth embodiment, the color material reduction process is performed on each pixel of the bitmap converted into the color material color used in the color printing apparatus, whereas in the sixth embodiment, the color printing apparatus Is different in that the color data input to the color data is converted into the color material color used in the color printing apparatus using the color material reduction color conversion profile capable of simultaneously executing the color material reduction processing. .

  The color printing apparatus 1e includes a CPU 11 that controls each section in the color printing apparatus 1e and various arithmetic processes, a data receiving circuit 21 that receives print data, and a work memory (RAM) that temporarily stores programs and data as work areas. 22, a program / resource memory (ROM) 23 for storing various programs and various data, an output image memory 24 for storing output image data for image formation, and an image forming circuit 20 for performing print control based on the output image data have.

  In FIG. 31, the components mainly related to the present invention are described among the components of the color printing apparatus 1e, and the color printing apparatus 1e may include components other than the components described above, or Some of the above-described components may not be included.

  Next, with reference to FIGS. 32 and 33, processing in the color printing apparatus 1e will be described. 32 and 33 is stored as a program in a storage unit such as the program / resource memory (ROM) 23 of the color printing apparatus 1e, and the CPU 11 stores the algorithm on the work memory (RAM) 22. Executed.

  The description of steps S1001 to S1006 in FIG. 32 is the same as the description of steps S301 to S306 in FIG.

  In the image data expansion process in step S1003, when the color of the print object in the print data input to the data receiving circuit 21 is converted to the color material color CMYK of the color printing apparatus 1e, the CPU 11 performs the color printing of the color printing apparatus 1e. Perform color conversion using a profile.

  FIG. 33 is a flowchart showing the procedure of the color conversion process.

  If it is determined that the color material reduction printing mode is not designated (S1101: NO), the process proceeds to step S1102, and the normal profile is read into the work memory 22.

  On the other hand, when it is determined that the color material reduction printing mode is designated (S1101: YES), it is determined whether the attribute is an image object (S1103). When it is determined that the attribute is an image object (S1103: YES), the first profile is read into the work memory 22 (S1104), and when it is determined that the attribute is an object other than the image object (S1103: NO). The second profile is read into the work memory 22 (S1105).

  The first profile according to the present embodiment is a color conversion profile adjusted for the image object color material reduction printing mode. The first saturation conversion circuit 31, the first under color removal / black plate of the fourth embodiment. This is a profile for executing processing similar to that performed by the generation circuit 32 and the first density conversion circuit 33 simultaneously with color conversion. The second profile according to the present embodiment is a color conversion profile adjusted for the object color material reduction print mode other than the image object. The second saturation conversion circuit 41 according to the fourth embodiment, the second lower This is a profile for executing processing similar to that performed by the color removal / black plate generation circuit 42 and the second density conversion circuit 43 simultaneously with color conversion.

  Then, the color data input to the color printing apparatus 1e is color-converted to CMYK, which is the color material color of the color printing apparatus 1e, using the profile read into the work memory 22 (S1106).

  As described above, according to the sixth embodiment, it is possible to achieve the same effects as the fourth embodiment and the fifth embodiment.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, in the above embodiment, the case where the color printing control device is included in the color printing device has been described. However, the color printing control device and the color printing device are separated and connected to each other. Also good.

  Moreover, in the said embodiment, although a printer is illustrated as a color printing apparatus, this invention is not limited to this. The present invention is also applicable to other color printing apparatuses such as an MFP (Multi-Function Peripheral) and a copying machine.

  The means and method for performing various processes in the color printing control apparatus of this embodiment can be realized by either a dedicated hardware circuit or a programmed computer. The program may be provided by a computer-readable recording medium such as a flexible disk or a CD-ROM, or may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is usually transferred to and stored in a storage unit such as a hard disk. The program may be provided as a single application software, or may be incorporated into the software of the device as one function of the device.

1 is a block diagram illustrating a configuration of a color printing apparatus 1 to which a color printing control apparatus according to a first embodiment of the present invention is applied. It is a figure which shows the algorithm of saturation conversion. It is a figure for demonstrating saturation conversion. It is a figure which shows the algorithm of density conversion. It is a figure which shows the algorithm of under color removal / black generation (UCR / BG). It is a figure for demonstrating under color removal / black version generation. It is a block diagram which shows the structure of the color printing apparatus 1a concerning the 2nd Embodiment of this invention. It is a flowchart which shows the procedure of the process in the color printing apparatus 1a. It is a flowchart which shows the procedure of a color material reduction process. It is a block diagram which shows the structure of the color printing apparatus 1b concerning the 3rd Embodiment of this invention. It is a flowchart which shows the procedure of the process in the color printing apparatus 1b. It is a flowchart which shows the procedure of a color conversion process. It is a block diagram which shows the structure of the color printing apparatus 1c to which the color printing control apparatus concerning the 4th Embodiment of this invention was applied. It is a figure which shows the structure of a 1st saturation conversion circuit and a 2nd saturation conversion circuit. It is a figure which shows the algorithm of saturation conversion. It is a figure which shows the structure of a 1st under color removal / black plate generation circuit and a 2nd under color removal / black plate generation circuit. It is a figure which shows the algorithm of under color removal / black version production | generation. It is a figure which shows the structure of a 1st density | concentration conversion circuit and a 2nd density | concentration conversion circuit. It is a figure which shows the algorithm of density conversion. (A) is a figure which shows an example of the CMYK density | concentration of an input pixel, (b) is a figure which shows a saturation conversion result. (A) is a figure for demonstrating a lower color component and a lower color removal amount, (b) is a figure which shows the result of having performed under color removal / black plate generation. It is a figure which shows an example of the dot pattern of the light / dark expression by a dither screen. It is a figure which shows the relationship between a printing image density and a dot rate. It is a figure for demonstrating an example of the data set to a saturation conversion rate table, a removal amount table, a generation amount table, and a density conversion rate table. It is a block diagram which shows the structure of the color printing apparatus 1d to which the color printing control apparatus concerning the 5th Embodiment of this invention was applied. It is a flowchart which shows the procedure of the process in the color printing apparatus 1d. It is a flowchart which shows the procedure of a color material reduction process. It is a flowchart which shows the procedure of 1st saturation conversion and 2nd saturation conversion. It is a flowchart which shows the procedure of 1st under color removal / black plate production | generation and 2nd under color removal / black plate production | generation. It is a flowchart which shows the procedure of 1st density | concentration conversion and 2nd density | concentration conversion. It is a block diagram which shows the structure of the color printing apparatus 1e to which the color printing control apparatus concerning the 6th Embodiment of this invention was applied. It is a flowchart which shows the procedure of the process in the color printing apparatus 1e. It is a flowchart which shows the procedure of a color conversion process.

Explanation of symbols

1, 1a-1e color printing device,
11 CPU
12 image memory,
13 attribute memory,
14 memory access control unit,
15, 15a first color material reduction processing unit,
16 Second color material reduction processing unit,
17 first selection circuit,
18 second selection circuit,
19 Screening processing unit,
20 Image forming circuit,
21 data receiving circuit,
22 working memory,
23 Program / resource memory,
24 output image memory,
151, 31 first saturation conversion circuit,
152, 33 first density conversion circuit,
153, 32 first under color removal / black plate generation circuit,
161, 41 Second saturation conversion circuit,
162, 43 second density conversion circuit,
163, 42 Second undercolor removal / black plate generation circuit.

Claims (26)

A color printing control apparatus that performs control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium,
A determination unit that determines whether or not a color material reduction printing mode for printing with reduced consumption of color material is set;
When the determination unit determines that the color material reduction printing mode is set, color material reduction is performed by performing color material reduction processing on each pixel of the bitmap converted to the color material color used for printing. An output unit for outputting processed data,
In the color material reduction process, among the plurality of chromatic color material components of each pixel, the density of the chromatic color material component having a density larger than a reference value determined from the density of the plurality of chromatic color material components. While reducing the saturation by increasing the density of the chromatic color material component having a density smaller than the reference value , and after the saturation conversion , Including undercolor removal / black plate generation in which at least part of the achromatic color component generated by the superposition is replaced with an achromatic color material,
A color printing control apparatus characterized by the above.   In the saturation conversion, a saturation conversion rate indicating a ratio of saturation after conversion to saturation before conversion is set for each pixel according to the saturation of a pixel to be processed. The color printing control apparatus according to 1.   The saturation conversion rate for the first pixel in the saturation conversion is larger than the saturation conversion rate for a second pixel having a lower saturation than the first pixel. The color printing control apparatus according to 2. The colorant reduction process further comprises a density conversion for reducing the concentration, color printing control apparatus according to any one of claims 1 to 3, characterized in that. 5. The color according to claim 4 , wherein in the density conversion, a density conversion rate indicating a ratio of the density after conversion to the density before conversion is set for each pixel according to the density of the pixel to be processed. Print control device. In the density conversion, according to density conversion rate for the first pixel, to claim 5, characterized in that it is larger than the density conversion rate for the second pixel a lower concentration than the first pixel Color printing control device. The color material reduction process includes a first process and a second process having a different process content from the first process.
According to the pixel of the attribute, wherein the color material reducing process is performed, according to claim 1-6 for the color material reduction process applied to the pixel is switched to the first processing or the second processing, it is characterized by The color printing control apparatus according to any one of the above. The attribute includes the type of print object to which the pixel belongs,
The color print control apparatus according to claim 7 , wherein the types of the print object are classified into at least an image object and a non-image object. Parameters for processing to be performed in the first processing and the second processing are set such that the color material reduction amount for the pixels of the image object is larger than the color material reduction amount for the pixels other than the image object. The color printing control apparatus according to claim 8 , wherein: Parameters of processing performed in the color material reducing process, according to any one of claims 1 to 9, which is set according to an instruction from a user, it is characterized in the operation unit on the color printing control apparatus Color printing control device. Parameters of processing performed in the color material reducing process is set based on the instructions contained in the print data input to the color printing control apparatus, any one of claims 1 to 1 0, characterized in that The color printing control apparatus according to item 1. A color printing control apparatus that prints a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium,
A determination unit that determines whether or not a color material reduction printing mode for printing with reduced consumption of color material is set;
When the determination unit determines that the color material reduction print mode is set, the color data input to the color print control device is converted into a color material reduction color conversion profile that can simultaneously execute color material reduction processing. A color conversion unit that performs color conversion for conversion to a color material color used for printing, and
In the color material reduction process, among the plurality of chromatic color material components of each pixel, the density of the chromatic color material component having a density larger than a reference value determined from the density of the plurality of chromatic color material components. While reducing the saturation by increasing the density of the chromatic color material component having a density smaller than the reference value , and after the saturation conversion , Including undercolor removal / black plate generation in which at least part of the achromatic color component generated by the superposition is replaced with an achromatic color material,
A color printing control apparatus characterized by the above. The saturation conversion rate indicating a ratio of saturation after conversion to saturation before conversion is set for each pixel according to the saturation of the pixel to be processed in the saturation conversion. The color printing control apparatus according to 1 or 2 . The saturation conversion rate for the first pixel in the saturation conversion is larger than the saturation conversion rate for a second pixel having a lower saturation than the first pixel. color printing control device according to 1 3. The colorant reduction process further comprises a density conversion for reducing the concentration, that color printing control apparatus according to any one of claims 1 2 to 1 4, characterized in. In the density conversion, in accordance with the density of the pixel to be processed, according to claim 1 5, characterized in that the density conversion ratio is set which indicates the ratio of the density after the conversion to the concentration before the conversion for each pixel Color printing control device. In the density conversion, wherein the density conversion ratio for the first pixel, to claim 1 6, characterized in that is larger than the density conversion rate for the second pixel a lower concentration than the first pixel Color printing control device. The color conversion profile for color material reduction has a first profile, and a second profile that is different from the first profile and the color material reduction processing content,
According to the attribute of the pixel subjected to the color conversion, the color material reduction color conversion profile used for color conversion applied to the pixel is switched to the first profile or the second profile. color printing control apparatus according to any one of claims 1 2 to 17. The attribute includes the type of print object to which the pixel belongs,
The color print control apparatus according to claim 18 , wherein the types of the print objects are classified into at least an image object and a non-image object. The color conversion parameters executed in the first profile and the second profile are such that the color material reduction amount for the pixels of the image object is larger than the color material reduction amount for the pixels other than the image object. The color printing control apparatus according to claim 19 , wherein the color printing control apparatus is set. In the under-color removal / black generation, all of the achromatic component generated by superposition of a plurality of color materials is replaced by an achromatic color material, it in any of claims 1-2 0, wherein The color printing control apparatus described. A color printing control method for performing control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium,
A determination step of determining whether or not a color material reduction print mode for printing with reduced color material consumption is set;
When it is determined that the color material reduction printing mode is set in the determination step, the color material reduction processing is performed on each pixel of the bitmap converted into the color material color used for printing. An output step for outputting processed data,
In the color material reduction process, among the plurality of chromatic color material components of each pixel, the density of the chromatic color material component having a density larger than a reference value determined from the density of the plurality of chromatic color material components. While reducing the saturation by increasing the density of the chromatic color material component having a density smaller than the reference value , and after the saturation conversion , Including undercolor removal / black plate generation in which at least part of the achromatic color component generated by the superposition is replaced with an achromatic color material,
And a color printing control method. A color printing control method for performing control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium,
A determination step of determining whether or not a color material reduction print mode for printing with reduced color material consumption is set;
When it is determined that the color material reduction printing mode is set in the determination step, the input color data is used for printing using a color material reduction color conversion profile capable of simultaneously executing the color material reduction processing. A color conversion step for performing color conversion for conversion to a color material color to be
In the color material reduction process, among the plurality of chromatic color material components of each pixel, the density of the chromatic color material component having a density larger than a reference value determined from the density of the plurality of chromatic color material components. While reducing the saturation by increasing the density of the chromatic color material component having a density smaller than the reference value , and after the saturation conversion , Including undercolor removal / black plate generation in which at least part of the achromatic color component generated by the superposition is replaced with an achromatic color material,
And a color printing control method. A color printing control program for performing control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium,
A determination procedure for determining whether or not a color material reduction print mode for printing with reduced color material consumption is set;
If it is determined that the color material reduction printing mode is set in the determination procedure, the color material reduction processing is performed on each pixel of the bitmap converted to the color material color used for printing. An output procedure for outputting processed data;
In the color material reduction process, among the plurality of chromatic color material components of each pixel, the density of the chromatic color material component having a density larger than a reference value determined from the density of the plurality of chromatic color material components. While reducing the saturation by increasing the density of the chromatic color material component having a density smaller than the reference value , and after the saturation conversion , Including undercolor removal / black plate generation in which at least part of the achromatic color component generated by the superposition is replaced with an achromatic color material,
A color printing control program. A color printing control program for performing control for printing a color image by superimposing an achromatic color material including at least black and a plurality of chromatic color materials on a print medium,
A determination procedure for determining whether or not a color material reduction print mode for printing with reduced color material consumption is set;
When it is determined that the color material reduction printing mode is set in the above determination procedure, the input color data is used for printing using a color material reduction color conversion profile capable of simultaneously executing the color material reduction processing. A color conversion procedure for performing color conversion for conversion to a color material color to be executed, and
In the color material reduction process, among the plurality of chromatic color material components of each pixel, the density of the chromatic color material component having a density larger than a reference value determined from the density of the plurality of chromatic color material components. While reducing the saturation by increasing the density of the chromatic color material component having a density smaller than the reference value , and after the saturation conversion , Including undercolor removal / black plate generation in which at least part of the achromatic color component generated by the superposition is replaced with an achromatic color material,
A color printing control program. It claims 2 to 4 or 2 5 A computer-readable recording medium a color printing control program according to.

Images