JP2007208531A - Multicolor printing apparatus and method of controlling same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform processing suitable to an object by setting different color conversion processing to a print job. <P>SOLUTION: An object of an input print job is determined, and the object of the print job is subjected to color conversion processing on the basis of a determination result and information designating color conversion processing set in each print job. When the object is a transparent object, color conversion processing is performed in a rendering color space, and when the object is gradation, color conversion processing is performed in a device color space. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multicolor printing apparatus that develops characters and graphics or draws natural images such as photographs.

  Conventionally, color data handled in a color printer or the like for printing graphics and image data is given by RGB values specified by a color mode or a command in the case of graphics, and in the case of image data, RGB dot sequential or RGB plane sequential. Given in the form. In addition, the color space for handling color data is not limited to RGB, but includes a YMC color space (by ink characteristics or the like) unique to a color printer, an XYZ color space defined by CIE, or the like.

  In any case, when printing is performed inside the color printer, color reproduction processing corresponding to the color space defined by the color printer is performed on the input color data (for example, conversion from RGB to YMCK). ) Actual printout is performed.

  In general, in color printers, when color matching with color data handled by other devices is considered, a standard color space is defined, and color correction that matches each device's light emission (color) characteristics. It is carried out. Here, the other device is a color display such as a color scanner or a CRT, for example.

  In this case, the color processing inside the color printer also corresponds to the reference color space, and for example, even if an image displayed on the color display is output by the color printer, it can be faithfully reproduced.

  For example, in order to handle the same color data in devices such as a color scanner, a color display, and a color printer, a reference color space, that is, a device-independent color space is defined, and a color space conversion process corresponding to each device is used. To the color space unique to each device. Thereby, color matching can be realized between the devices.

  Actually, since the color reproduction range in each device is different due to the physical characteristics inherent in each device, it is difficult to pursue colorimetric matching. However, in general, color correction that minimizes the color difference using a color difference formula represented by CIE1976 L * a * b * has been proposed.

  Many color difference formulas have been proposed for evaluating whether two colors expressed on different media are equal, such as a screen for a color display and a recording paper for a color printer. However, there is nothing that has been absolutely established, and in many cases, they are used properly depending on the purpose of use.

  At the same time, there are several methods for color reproduction, which are also properly used depending on the purpose. When the above-described color matching is taken into consideration, the evaluation method inevitably differs depending on what kind of color reproduction is intended. In particular, in a color printer, the internal color reproduction method is an important factor affecting the image quality of the printed matter to be output.

  In general, as described above, it has been attempted to perform correction so as to minimize the color difference using the CIE1976 L * a * b * color difference formula. This method is effective when color data read from a color scanner is reproduced by a color printer. This is because the original is a reflective original (color that has been reproduced on paper) and it is relatively easy to reproduce it with ink from a printing apparatus. Basically, since the mechanism of physical color development is the same, color reproduction is easier compared to other media even if there is a difference in ink characteristics and the problem of density (tone).

  However, colors that are emitted on the screen of a color display have physical properties that are different from those of reflective originals, and there is a limit to the pursuit of color reproducibility by a general color difference formula. When an image output on such a medium is a natural image, color reproduction called preferred matching is often used in many cases. This is intended to achieve more favorable color reproduction for some of the most important colors in the image (for example, human skin color) apart from the point of whether the reproduced image is the same color as the original image It is.

  However, when handling data such as natural images, even if such color reproduction is effective, color reproduction that does not consider uniform colors when handling data such as computer graphics (CG) images. Inconvenience occurs in processing.

  Therefore, if the color reproduction process can be changed according to the data to be processed, the above problem can be solved. Therefore, it is possible to provide a multicolor printing apparatus that can print out with a more preferable image quality by selecting a color reproduction process corresponding to the data to be handled.

  FIG. 1 is a diagram illustrating main processing relating to color processing in a conventional printer. As shown in FIG. 1, input data is first temporarily stored in the input unit 101 and then sent to the data analysis unit 102. Then, the data analysis unit 102 analyzes whether the input data is image data or CG data. Specifically, the data format of the input data is recognized, and if the pixel size and the RGB value of each pixel are arranged in a dot sequential format, it is analyzed as image data. Further, if data representing the type of figure and its coordinate values, color specified RGB data, and the like are arranged in a format that matches the processing system, the data is analyzed as CG data.

  Next, based on the result analyzed by the data analysis unit 102, the input data is branched into a development system suitable for the processing of the data. That is, if the result analyzed by the data analysis unit 102 is image data, the input data is sent from the data analysis unit 102 to the image development system 103. The image development system 103 converts the image data into YMC data with reference to the color conversion processing unit 104, develops the drawing data, and renders the data in the page buffer 107.

  If the result analyzed by the data analysis unit 102 is CG data, the input data is sent from the data analysis unit 102 to the CG development system 105. The CG development system 105 converts the data into YMC data with reference to the color conversion processing unit 106, develops the drawing data, and draws the data in the page buffer 107.

  In contrast, SVG (Scaleable Vector Graphic) objects that place importance on the display of graphic designs on a monitor include transparent figures and gradation figures. Hereinafter, each will be described in detail with reference to the drawings. First, a transparent figure will be described.

  FIG. 2 is a diagram for explaining a combining process for combining two graphic data. In general, an overlapping portion of colors of an image to be drawn can be calculated according to an arbitrary color mixture calculation expression. In this example, it is assumed that two figures 210 and 220 are input as images, one figure 210 is transparent and has α_CG1 as a synthesized attribute value, and another figure 220 has transparency and α_CG2 as a synthesized attribute value. Further, since the transparency and composite attribute values of each figure are set for each pixel forming the image, the composite pixel can be calculated for each pixel at the time of synthesis.

  Since the overlapping portion 242 and the other portions 241 and 243 are different in color matching processing, the region 231 to 233 are appropriately decomposed as shown in FIG. Such a composition process using “transparency, composition attribute value” may be called “α blend”.

  Here, a method of performing color matching on an object (figure) to which α blend is applied will be described. In general, two methods are conceivable as listed below.

  The first method is a case where color matching processing (gamut compression processing) is performed at the stage before α blending as shown in FIG. A PDL (page description language) job includes information on each figure (object) necessary to form a print page. In general, an arbitrary color space can be designated independently for each figure. For example, a standard color space A (for example, A-RGB color space) is designated for the rectangular object 210 shown in FIG. 2, and another rectangular object 220 has another standard color. It is assumed that the space B (similarly, the B-RGB color space) is designated.

  Further, it is assumed that a device for printing in the system is a printer A, and an input color space to the printer A is defined as an RGB color space (that is, a device RGB color space).

  Here, when performing color conversion from a device-independent color space, for example, a color space such as XYZ or Lab, to a device color space, the ICC profile of the printer A (for example, conversion from XYZ to device RGB) is used. It is configured.

  The difference in color space between the two rectangular objects shown in FIG. 2 can be made uniform in one color space (here, device color space) by using the ICC profile of printer A.

  Specifically, the rectangular object 210 is converted from the A-RGB color space to the XYZ color space, and converted from the XYZ color space to the device color space of the printer A using the ICC profile of the printer A. At this time, color space compression is performed in accordance with the gamut of the printer device (gamut map + color conversion). Similarly to the rectangular object 210, the same processing is applied to the rectangular object 220, and device RGB values can be obtained.

  By these conversions, the color spaces of the two rectangular objects to be combined can be made uniform, and each object is subjected to the combining process in the same color space, that is, the device RGB color space. The On the printer side, the device RGB color space value after the synthesis of each object is received, the device RGB color space is converted from the device RGB color space to the printer color space CMYK inside the printer, and print output is executed.

  Next, as a second method, a case will be described in which color matching processing (gamut compression processing) to the device color space is performed after synthesizing an object (figure) to which α blend is applied. Here, it is assumed that a rendering color space (the definition here is broad, for example, a color space for performing operations such as composition is the same) is defined as a PDL script or system definition. In addition, the rendering color space is not a color space that defines the gamut of the printer, but a color space defined by a standard such as a display (for example, a standard color space sRGB).

  As described above, a PDL (page description language) job includes information on each figure (object) necessary to form a print page. In general, an arbitrary color space can be designated independently for each figure.

  A standard color space A (for example, A-RGB color space) is designated for the rectangular object 210 shown in FIG. 2, and another standard color space B is specified for another rectangular object 220. Assume that (similarly, the B-RGB color space) is designated.

  As shown in FIG. 4, color conversion is first performed from each color space to a rendering color space. Here, when the sRGB color space is designated as the rendering color space, there is no need to perform color space compression, so color space conversion (linear conversion in which white point, chromaticity, γ, etc. are affected) is simply performed. Is done. Next, the two rectangular objects are converted into the same color space (rendering color space), and then a composition process is executed. Thereafter, the rendering color space is converted into a device color space (device RGB color space). At this time, since the device color space has a printer gamut, color space compression is performed (gamut map + color conversion).

  On the printer side, the device RGB color space value after the synthesis of each object is received, the device RGB color space is converted from the device RGB color space to the printer color space CMYK inside the printer, and print output is executed.

  Here, the above-described two types of methods (FIGS. 3 and 4) are contrasted, and which method is preferably applied is considered. First, as a premise, it is considered that PDL defines the operation of the synthesis process. Based on this assumption, consider the case where the rendering result of a PDL job is output to a display or a printer.

  As an image process, it is natural to think that when a synthesis process is performed in one rendering color space and the synthesis result flows to each device, it is converted into the color space of each device. The composition process is a kind of arithmetic operation. If the applied color space is different, the result is also different. If the composition process is performed after conversion to the color space in each device, inconvenience occurs.

  Therefore, generally speaking, it can be said that the second method (FIG. 4), that is, a method of performing color space compression to the device color space after combining processing is preferable.

  Next, a case where a gradation exists in the object and the gradation processing is performed will be described. Here, the gradation is a figure, in which several points, for example, a rectangular area is defined, and the end point color is defined by a plurality of points. The intermediate color value is a figure expressed by a change from the end point to the end point.

  FIG. 5 is a diagram for explaining gradation processing. When color matching processing is performed on this gradation figure, the following problems may occur due to quantization errors caused by calculation.

  For example, consider a gradation object that changes from red to black from the start point to the end point. As shown in FIG. 5, this color conversion needs to be performed according to the position Vi on the drawing line. At this time, when the change (V1−V2) of the drawing position is loose with respect to the movement distance (X2−X1), that is, when the value of (V1−V2) is relatively low, it is caused by a quantization error by calculation. The color conversion result may not be a desired value.

  This problem will be described with reference to FIG. 6. This corresponds to a case where each RGB pixel is converted into a CMYK value by color matching processing after the gradation object is developed in the RGB color space. The value of each CMYK pixel is affected by the quantization error caused by the color matching process. That is, for example, even when the change on the CMYK color space side has to be monotonously increased, there may be a case where the monotonous increase does not occur due to the influence of the quantization error as shown in FIG.

  In order to solve this, for example, it is conceivable to interpolate the color change value in the gradation on the device color space based on the color matching processing and the color matching result at the gradation control point.

  That is, with reference to FIG. 6B, this corresponds to the case where the color matching process is first performed only on the end points of the gradation object, and then intermediate pixel drawing is generated in the CMYK rendering process. If an image is formed on the premise of gradation in the CMYK color space, the image can be formed while satisfying the condition of monotonous increase.

Therefore, generally speaking, in the case of gradation, the method of (B) shown in FIG. 6, that is, the method of generating an intermediate pixel in the device color space after compressing only the end points into the device color space is preferable. .
Japanese Patent Laid-Open No. 2001-218079

  As described above, it is desirable to perform processing in the RGB color space (rendering color space) when α blend is present in the object, and in the device CMYK color space (device color space) when gradation is present. However, the conventional printing system has a problem that it is difficult to apply different color spaces.

  Further, as described above, if only one method is employed, it is not possible to satisfy all printing requirements. For example, if you want to perform high-speed printing or if you want to process a job with multiple threads and use only the RGB color space as the rendering color space, the internal structure becomes very complex and difficult to implement. .

  SUMMARY An advantage of some aspects of the invention is that different color conversion processing is set for a print job and processing suitable for an object is performed.

  The present invention is a multicolor printing apparatus, wherein a determination unit that determines an object of an input print job, a determination result by the determination unit, and information that specifies a color conversion process set for each print job Color conversion processing means for color-converting the object based on the color conversion processing means, and the color conversion processing means performs color conversion processing in a rendering color space when the object is a transparent object, and device when the object is a gradation. It is characterized by color conversion processing in a color space.

  The present invention is also a control method for a multicolor printing apparatus, wherein a determination step for determining an object of an input print job, a determination result in the determination step, and a color conversion process set for each print job A color conversion processing step for performing color conversion processing on the object based on the information for designating the object, and when the object is a transparent object, the color conversion processing step performs color conversion processing in a rendering color space, In the case of, color conversion processing is performed in the device color space.

  According to the present invention, different color conversion processing can be set for a print job, and processing suitable for an object can be performed.

  The best mode for carrying out the invention will be described below in detail with reference to the drawings.

[First Embodiment]
FIG. 7 is a diagram illustrating a method of processing a print job by the printer according to the first embodiment. Here, the print job is input to the printer 720 as a job script 710. Further, one color ticket 731 is issued for one job script 710, and it is configured so as to be appropriately passed to necessary modules such as a PDL interpreter 721, a render 722, a post-render color conversion unit 723, and the like.

  First, when a transparent object (α blend object) is passed to the PDL interpreter 721, the color of the object is converted to a rendering color space (color space compression is not applied). Next, composition processing is performed inside the renderer 722, and then color conversion is performed by the post-render color conversion unit 723. Here, conversion is performed from the rendering color space to the device color space (color space compression is applied here).

  On the other hand, in the case of a gradation object, the PDL interpreter 721 performs color matching processing only for the end points. At this stage, color space compression to the printer color space is performed only at the end points to obtain CMYK values, which are passed to the renderer 722. When executing an instruction for rendering a gradation by the renderer 722, intermediate pixel values are generated based on the CMYK values of the end points. For example, while performing calculation such as linear interpolation, the pixel value between them is calculated. For the gradation object, the processing of the post-render color conversion unit 723 is not necessary.

  Individual objects are processed differently, but their operations are controlled with reference to a color ticket structure 731 generated based on information from the UI setting unit 730. The information of the color ticket structure 731 is information used by each processing unit (PDL interpreter 721, render 722, post-render color conversion unit 723) to read as appropriate and control operations in each process.

  Next, a specific print job process performed by the printer according to the first embodiment will be described in detail with reference to FIG.

  FIG. 8 is a block diagram illustrating an example of the configuration of the printer according to the first embodiment. In FIG. 8, the print job generated by the application 810 is transferred to the printer 820 via a network (not shown). The printer 820 includes an object determination unit 824 that determines an object for each PDL interpreter 721, render 722, and post-render color conversion unit 723. Then, the object determination unit 824 determines whether the object is a transparent object or a gradation object. Each object data is appropriately transferred to the processing unit 825.

  The processing unit 825 has a structure in which the color conversion processing unit 826 is appropriately called for color matching processing. The color conversion processing unit 826 is configured to switch the conversion processing contents in a timely manner under the control of the printer control unit 823.

  For example, when a transparent object is processed or when a composite color needs to be calculated, the conversion process 827 is called. Further, when color conversion is performed for one color such as an end point of a gradation object, a conversion process 828 is called. The conversion processing 827 performs transparency and composition processing on the input objects C1 and C2 based on the LUT, performs color matching processing, and outputs the result. Also, the conversion processing 828 performs color matching processing on the input object C based on the LUT and outputs the result.

  Further, the control of the printer control 823 is determined according to the information of the color ticket structure 822. The color ticket structure 822 is set based on information from the UI setting unit 821 of the printer 820, and is used to switch the processing content of the color conversion processing 826.

  Next, the configuration of the print processing block of the printer 820 and the setting screen of the UI setting unit 821 according to the first embodiment will be described with reference to FIG.

  FIG. 9 is a diagram illustrating an example of a configuration of a print processing block and a setting screen according to the first embodiment. Here, a print job from the client PC 900 is output to the print processing block 920, and data is output to an engine unit (not shown) by processing in the print processing block 920.

  As shown in FIG. 9, the print processing block 920 includes several internal processing blocks. First, the print response processing block 921 responds to a print request from the client PC 900 input from a network or the like, and performs a reception process of print data transmitted from the client PC 900. Next, the spooling processing block 922 temporarily stores the print data received by the print response processing block 921 in the spooling area.

  A print processing block 923 performs an image forming process for performing printing after performing an analysis process on the print data. A transparent object processing block 924 and a gradation processing block 925 perform processing for calculating α blend and gradation included in the print data. The control block 926 controls processing of the transparent object processing block 924 and the gradation processing block 925 in accordance with a printing mode described later.

  Reference numeral 910 denotes a user interface for the user to provide a printing mode, which is displayed on the setting screen of the UI setting unit 821. In the example shown in FIG. 9, each of “high quality print mode” 911, “high-speed print mode” 912, “default setting” 913, “detail setting” 914, “OK” 915, “apply” 916, and “cancel” 917 An instruction button is displayed.

  For example, when the high image quality printing mode 911 is selected, the RGB color space (rendering color space) is applied to the α blend object, and the device CMYK color space (device color space) is applied to the gradation. When the high-speed printing mode 912 is selected, only the RGB color space is applied as the rendering color space.

  According to the first embodiment, the RGB color space (rendering color space) is applied to the α blend object, and the device CMYK color space (device color space) is applied to the gradation using the color ticket structure. The color space can be switched.

  Also, in the high-speed printing mode, when only the RGB color space is used as the rendering color space, processing can be performed without any problem by issuing a color ticket structure with different settings for the corresponding print job.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described in detail with reference to the drawings. In the first embodiment, as a process for the gradation object, first, color matching is performed only for the end points, and then drawing of the intermediate pixel is generated by the CMYK rendering process. Thus, if gradation is formed in the CMYK color space, it is possible to form an image that satisfies the condition of monotonous increase, for example.

  However, since the gradation change is defined in the color color space in the PDL script, strictly speaking, the color change in the rendering color space must be expressed in the device color space. In that sense, there is a problem that faithful color reproduction cannot be achieved if intermediate pixels are generated using linear interpolation or the like in a device color space such as CMYK.

  Therefore, in the second embodiment, in order to avoid this, the gradation object is appropriately divided, and color matching processing is performed on the end point of each divided object.

  FIG. 10 is a flowchart showing the gradation object dividing process. First, in step S1001, initialization processing is performed, and in step S1002, GIRD generation processing is performed. For example, the division resolution of the gradation object can be set by a UI setting unit to be described later. Here, the number of grids is determined from the resolution designation value and the size of the target object at the time of rendering development. Specifically, when 10 DPI is specified as the resolution in the vertical and horizontal directions, an image is formed with a size of 5 inches if the developed size of the gradation object is 600 DPI and the printer has 3000 pixels. In this case, if the expected gradation resolution is 10 DPI, 50 is an appropriate value for the number of divisions.

  Next, in step S1003, a device CMYK value is obtained as a color matching value of an end point for each grid. At this time, the difference values between the obtained CMYK values of the grid points and the vertical and horizontal grid points are recorded as DXi and DYi. Then, DXi and DYi are compared with the maximum difference value (DMX, DMY), and when DXi and DYi exceed the maximum difference value, DMX and DMY are updated as appropriate. The above processing is performed for all the grids.

  Next, in step S1004, the maximum difference value (DMX, DMY) is substituted into DX, DY. In step S1005, a threshold value specified by a UI setting unit, which will be described later, is compared with DX and DY. If either DX or DY exceeds the threshold value, the process proceeds to step S1006 to re-divide the grid.

  Although subdivision is performed according to the threshold value, if the difference value, that is, the change in CMYK value between grids is large, it means that the color change in the area does not maintain linearity, and the current grid division is performed. This is because it is necessary to divide into smaller areas.

  In step S1006, the number of grids is increased. For example, if the number of vertical and horizontal GRIDs is 50, the grid number 100 is set. In step S1007, it is determined whether or not the set number of grids exceeds the grid limit value of the system. If not, the process returns to step S1003 to repeat the above process.

  For example, 300 is appropriate as the value of the grid limit in a printer of about 600 DPI. Further, since it is presumed that the image quality is satisfied at a visual characteristic of about 200 to 300, 200 is usually set as the grid limit value.

  Next, a print job process performed by the printer according to the second embodiment will be described in detail with reference to FIG.

  FIG. 11 is a diagram illustrating a method of processing a print job by the printer according to the second embodiment. Here, the print job is input to the printer 1120 as a job script 1110. A color ticket 1131 is issued to each job, and is appropriately passed to necessary modules such as a PDL interpreter 1121, a render 1122, and a post-render color conversion 1122.

  First, when a transparent object (α blend object) is passed to the PDL interpreter 1121, the color of the object is converted into a rendering color space (no color space compression). Next, a composition process is performed inside the render 1122, and then color conversion is performed by the post-render color conversion unit 1123. Here, the rendering color space is converted to the device color space (color space compression is applied).

  On the other hand, in the case of a gradation object, subdivision processing and color matching processing are performed at the stage of the PDL interpreter 1121. As described with reference to FIG. 10, the re-division processing for the gradation object is divided based on the conditions such as the gradation resolution and the threshold value of the difference value. Information such as the gradation resolution and the threshold value of the difference value is stored inside the color ticket structure 1131. Here, each of the divided gradation objects is configured such that a device CMYK value at each end point is obtained, and all of the information is passed to the render 1122.

  When the rendering command is executed by the render 1122, intermediate pixel values are generated based on the CMYK values of the end points. For example, while performing calculation such as linear interpolation, the pixel value between them is calculated. As described above, the post-render color conversion unit 1123 does not need to process the gradation object.

  The two objects are processed differently, but their operations are controlled with reference to the color ticket structure 1131. Information of the color ticket structure 1131 is configured so that each processing block (PDL interpreter 1121, render 1122, post-render color conversion 1123) appropriately reads and controls operations in each process.

  The color ticket structure 1131 is generated based on information from the UI specifying unit 1130 as in the first embodiment.

  Next, the configuration of the print processing block of the printer 1120 and the setting screen of the UI setting unit 1130 according to the second embodiment will be described with reference to FIG.

  FIG. 12 is a diagram illustrating an example of a configuration of a print processing block and a setting screen according to the second embodiment. The configuration of the print processing block 1210 shown in FIG. 12 is the same as that of the first embodiment described with reference to FIG. The setting screen for setting the printing mode is the same as that in the first embodiment. However, in the second embodiment, a more detailed setting screen is displayed and the settings can be customized.

  As shown in FIG. 12, when a detailed setting button is pressed, a detailed setting item is opened. Here, a color matching mode (in this case, either Pre or Post processing or automatic) can be selected for each of the transparent object and the gradation object. In the example shown in FIG. 11, PostCMS is selected for the α blend object, and Post render processing is selected for the gradation object.

  The example shown in FIG. 12 indicates that automatic setting or manual setting can be selected when the Post render process is selected for a gradation object. Here, when the manual setting is further selected, as shown in FIG. 12, the grid resolution and the difference threshold value for processing the gradation can be set.

  According to the embodiment, the color space applied to each object is switched using the color ticket structure, so that the RGB color space (rendering color space) is used for the α blend object, and the device CMYK color space (device) is used for the gradation. Color space). As a result, an image printed with the α blend object can realize color reproduction consistent with other devices such as a monitor display. Also, with a gradation image, a smooth and beautiful gradation image that is not affected by quantization errors during color matching processing can be obtained.

  In addition, even if the printing system is configured to process jobs in multiple threads inside the printer, it can operate without interfering with each other by issuing a color ticket structure for each job thread. Become.

  Also, when switching the printing mode, for example, when using only the RGB color space as the rendering color space in the high-speed printing mode, processing can be performed without problems by issuing a color ticket with a different setting for the corresponding job. .

  Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it is applied to an apparatus (for example, a copier, a facsimile machine, etc.) composed of a single device. It may be applied.

  In addition, a recording medium in which a program code of software for realizing the functions of the above-described embodiments is recorded is supplied to the system or apparatus, and the computer (CPU or MPU) of the system or apparatus stores the program code stored in the recording medium. Read and execute. It goes without saying that the object of the present invention can also be achieved by this.

  In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium storing the program code constitutes the present invention.

  As a recording medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like is used. be able to.

  In addition, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the following cases are included. That is, when the OS (operating system) running on the computer performs part or all of the actual processing based on the instruction of the program code, and the functions of the above-described embodiments are realized by the processing.

  Further, the program code read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. After that, based on the instruction of the program code, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing. Needless to say.

It is a figure which shows the main processes regarding the color process in the conventional printer. It is a figure for demonstrating the synthetic | combination process which synthesize | combines two figure data. It is a figure which shows the example which performs a color matching process (color space compression) before synthesize | combining a transparent figure. It is a figure which shows the example which performs a color matching process (color space compression) after synthesize | combining a transparent figure. It is a figure for demonstrating the process of gradation. It is a figure which shows the quantization error in a gradation process, and a CMYK rendering process. FIG. 6 is a diagram illustrating a method for processing a print job by the printer according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a configuration of a printer according to the first embodiment. FIG. 3 is a diagram illustrating an example of a configuration of a print processing block and a setting screen according to the first embodiment. It is a flowchart which shows the division | segmentation process of a gradation object. FIG. 10 is a diagram illustrating a method for processing a print job by a printer according to a second embodiment. FIG. 10 is a diagram illustrating an example of a configuration of a print processing block and a setting screen in a second embodiment.

Claims (6)

A multicolor printing device,
A discriminating means for discriminating an object of the input print job;
Color conversion processing means for performing color conversion processing on the object based on a determination result in the determination means and information designating color conversion processing set for each print job;
The multi-color printing apparatus, wherein the color conversion processing means performs color conversion processing in a rendering color space when the object is a transparent object, and performs color conversion processing in a device color space when the object is a gradation. Processing means for processing the print job in a multi-thread manner;
The multicolor printing apparatus according to claim 1, wherein the information specifying the color conversion process is issued for each job thread. If the object is a gradation, means for forming intermediate pixels in the device color space;
The multicolor printing apparatus according to claim 1, further comprising subdivision means for subdividing the object. A control method for a multicolor printing apparatus,
A determination step of determining an object of the input print job;
A color conversion processing step of performing color conversion processing on the object based on the determination result in the determination step and information specifying the color conversion processing set for each print job;
In the color conversion processing step, when the object is a transparent object, color conversion processing is performed in a rendering color space, and when the object is gradation, color conversion processing is performed in a device color space. .   The program for making a computer perform each procedure of the control method of the multi-color printing apparatus of Claim 4.   A computer-readable recording medium on which the program according to claim 5 is recorded.

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