JPH09187999A - Color correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent change in density due to change of an output device with time when a printing data is to be reused in a printing system which can store the printing data in a secondary memory device. SOLUTION: A color correcting device comprises a color data extracting means 4 which extracts a color data included in a printing data rasterized by an analyzing means 1, a patch data generating means 5 for generating a data for measuring patch from the color data, a patch measuring means 6 which measures a patch outputted by an output means 3 and stores an obtained color data as a reference color data in a secondary memory means 2 together with the printing data and the color data, a difference computing means 7 which calculates a difference between a measured data from the patch by the color data which has been stored together with the printing data to be reused and the reference color data which has been stored together with the color data, and a difference applying means 8 for applying the difference to the printing data to be reused. Thus, reproduction of a correct color can be realized per document.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color proofing device,
More particularly, it relates to a color proofing apparatus for a printing system having a secondary storage device, which prints data sent from an external device.

[0002]

2. Description of the Related Art When a document described in a page description language is received, and this is expanded into printable print data and printed, the expanded print data is saved in a secondary storage device and saved. There is known a printing apparatus that reads out the print data again and prints the print data (for example, Japanese Patent Laid-Open No. Hei 6).
No. 191100).

In color electrophotographic copying machines and color printing apparatuses such as computers and facsimiles, there is an apparatus for adjusting the density of an output image by detecting the gradation density of the output image. For example, JP-A-63-
The apparatuses described in JP-A-113568 and JP-A-4-77060 store pattern data serving as a density reference, detect an image formed based on the pattern data, and detect the pattern of the image. The data is controlled so that the data is compared with the stored pattern data so that the two data match, and the printing characteristics that change depending on the installation environment are corrected to obtain stable color reproducibility.

[0004]

In the conventional color printer with a color proofing function, the color proofing of the density is performed for all the color gamuts that can be represented by the output device. Also, in image data consisting of characters and graphics, unlike photographic images, the number of colors used there is not so large, color calibration for all color gamuts is not necessary,
Conventional color proofing is performed uniformly on any print data, although it need only be done for the colors used in the document.

Further, when the print data stored in the secondary storage device is printed, the state of the output device actually printed is not the same as the state when the print data is stored in the secondary storage device. There is a problem that the color density may change as compared with the image.

The present invention has been made in view of the above circumstances, and in a printing system capable of storing print data expanded in a printable manner in a secondary storage device, print data stored in the secondary storage device. When printing, the change in density due to changes over time in the output device, etc. can be proofread in document units, and this makes it possible to calibrate each document without performing color calibration for all the gamuts that the printing device can represent. It is an object of the present invention to provide a color proofing device that can perform color proofing.

[0007]

FIG. 1 is a diagram showing the principle configuration of a color proofing apparatus according to the present invention. In this figure, a color proofreading device analyzes a document described in a page description language from an external device and develops it into printable print data, and an analysis means 1 that saves the developed print data for reuse. A secondary storage means 2 to be stored and an output means 3 for reading and printing the print data stored in the secondary storage means 2 for use in a printing system,
Color data extraction means 4 for extracting color data included in the print data developed by the analysis means 1, patch data generation means 5 for generating patch data for measurement based on the extracted color data, and generation The patch output by the output unit 3 is measured based on the patch data obtained, and the obtained color data is used as a reference together with the print data developed by the analysis unit 1 and the color data extracted by the color data extraction unit 4. Measurements obtained from the patch measurement means 6 stored in the secondary storage means 2 as color data and the patch output based on the color data stored in the secondary storage means 2 together with the print data to be reused. The difference calculation means 7 for calculating the difference between the data and the reference color data stored in the secondary storage means 2 together with the color data, and the difference calculation means 7. It is constituted by the difference application means 8 to be applied to the print data sent to the output unit 3 in an attempt to reuse the issued difference.

According to the above configuration, in the printing system, first, when the document sent from the external device is stored in the secondary storage means 2 for reuse,
The analyzing unit 1 develops the document into print data, and the color data extracting unit 4 extracts color data from the print data. From the extracted color data, patch data generation means 5 generates patch data, and the output means 3 outputs the patch data. The patch measuring unit 6 measures color data of the output patch, and the color data is analyzed by the analyzing unit 1.
It is stored in the secondary storage means 2 as the reference color data together with the print data in step 1 and the color data in the color data extraction means 4.

When the document stored in the secondary storage means 2 is reused, the print data corresponding to it is read out. At that time, the color data and the reference color data stored together with the print data are also read. The read color data is sent to the patch data generation means 5 to generate patch data, which is output from the output means 3 as a patch. The patch measuring means 6 measures the color data of the output patch, and the measured color data is input to the difference calculating means 7 together with the reference color data previously read from the secondary storage means 2, and both of them are measured. The difference is calculated. The calculated difference is applied by the difference applying unit 8 to the print data previously read from the secondary storage unit 2, whereby the document is color-calibrated and output from the output unit 3.

According to the present invention, by performing color calibration on each print data stored in the secondary storage means 2,
It is possible to perform color reproduction on a document-by-document basis, which is close to the output when the output unit is color-adjusted, without performing color adjustment of the entire printing system.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. An external device expands a document described in page description language (PDL) into printable print data, saves it in a secondary storage device, and stores it. A case will be described as an example in which the applied print data is applied to a printing system that can read out and print out the print data.

FIG. 2 is a block diagram showing a configuration example of a printing system to which the color proofing apparatus of the present invention is applied. The printing system includes a print control device 20 that receives a document described in PDL from an external device 10 such as a workstation or a personal computer, and expands the print data into printable print data, an output device 40 that prints the print data, and a printing device. Secondary storage device 5 for storing data for reuse
0 and. The print control device 20 basically receives a document from the external device 10, a spool unit 22 for storing the received document, and a document extracted from the spool unit 22 for analysis and printing. An analysis unit 23 that expands the print data into possible print data and saves the print data in the secondary storage device 50, a development unit 24 that extracts the saved print data, and a memory 25 that forms an image for one page by the extracted print data. , And the output unit 26 that outputs the image data to the output device 40.

The print control device 20 further includes an analysis unit 23.
CMYK regarding characters and graphics used in the document from the print data expanded in
A color data extraction unit 31 that extracts (cyan, magenta, yellow, and black) color data and stores it in the secondary storage device 50, and a patch creation unit that creates a measurement patch (test pattern) from the extracted CMYK color data. 32, a patch output unit 33 that outputs the created patch to the output device 40, a color space conversion unit 34, a reference color data acquisition unit 35 that extracts the reference color data stored in the secondary storage device 50, Color data and reference color data acquisition unit 3 from the color space conversion unit 34
5, a difference calculation unit 36 that receives the reference color data from 5 and calculates a difference between them, a difference application unit 37 that applies the calculated difference to the print data extracted by the expansion unit 24, and these components. An instruction unit 38 for giving an instruction from the user as to whether or not a patch is required is provided, and these components constitute a color calibrating device together with a patch measuring unit 39 for measuring the patch output by the output device 40. ing.

The document described in PDL from the external device 10 is received by the receiving unit 21, and is temporarily stored in the spool unit 2.
Stored in 2. The analysis unit 23 takes out one document from the spool unit 22 and develops it into print data. At this time, if the user gives an instruction to create a patch, the CMYK relating to the characters and graphics used in the document from the print data by the color data extraction unit 31.
Color data is extracted and the CMYK color data is sorted to create a table. The patch creation unit 32 creates patch data for measurement from the CMYK color data table created by the color data extraction unit 31. When the created patch is sent from the patch output section 33 to the output device 40,
The output device 40 outputs patch data for measurement.
Here, it is assumed that the output device 40 is color-adjusted to a correct color or set to a color desired by the user.
The patch data output is the patch measurement unit (colorimeter) 39
Read, which measures the values in the absolute color space of the colors used in this document.
Since the measured value is expressed in the L ^* a ^* b ^* color space, the color space conversion unit 34 converts the measured value into the CMYK color space, and this is used as the reference color data, and the printing developed by the analysis unit 23 is performed. The data and the CMYK color data extracted by the color data extraction unit 31 are stored in the secondary storage device 50.
Here, the reference color data is numbered together with the CMYK color data stored together, and is stored in the form of a binary set for each number. C if there is no patch creation instruction
The reference color data is not created together with the MYK color data, and only the print data is stored in the secondary storage device 50.

Next, when outputting the document stored in the secondary storage device 50, the expansion unit 24 extracts the print data of one document from the secondary storage device 50.
At this time, if the user gives an instruction to print a patch for color calibration, the patch creation unit 32 creates the patch data by reading the CMYK color data stored together with the print data of the document, and outputs the patch data. Part 33
To the output device 40, and the output device 40 outputs the patch in the current output state. The output patch is measured by the patch measuring unit 39, and the current color state of the output device 40 is measured. The value measured here is converted into the CMYK color space by the color space conversion unit 34 and becomes CMYK color data. The CMYK color data is calculated by the difference calculation unit 36.
Passed to. On the other hand, the reference color data acquisition unit 35 acquires the stored reference color data from the secondary storage device 50 and transfers it to the difference calculation unit 36. The difference calculation unit 36 receives the delivered CM
The difference between the YK color data and the reference color data is calculated to obtain the adjusted CMYK color data. This adjustment CMYK
The color data is passed to the expansion unit 24 by the difference application unit 37. The expansion unit 24 adjusts the CMYK color data values existing in the print data expanded in the memory 25 to CMYK.
Change to color data value. As a result, the print data is calibrated to a color close to the color of the color-adjusted output device. The color-calibrated print data is passed to the output device 40 by the output unit 26, printed and output by the output device 40. As for the output result, in the current state of the output device 40, it is possible to reproduce a color close to the output result when the output device 40 is color-adjusted.

As described above, the print control device 20 writes a character or draws a line after designating the color to be drawn by the character data and graphics data in the document described in PDL sent from the external device. An image for one page is formed by performing operations such as painting and painting. The color proofing apparatus of the present invention performs color adjustment of the entire printing system by storing all the colors designated when the color is designated and the color data obtained from the actual output result of the color data. It is possible to perform color composition on a document-by-document basis according to each document without any need.

FIG. 3 is a flow chart showing the flow when saving print data. First, the document received from the external device 10 is developed into print data by the analysis unit 23 (step S1). Next, it is determined whether or not there is a patch creation instruction from the user (step S2), and if there is a patch creation instruction, the color data extraction unit 31 relates to the characters and graphics used in the document. Extracted CMYK color data and extracted CMYK
The color data is sorted to create a CMYK color data table (step S3). The patch creating unit 32 creates patch data based on the data of the created CMYK color data table (step S4). next,
It is determined whether or not there is a patch printing instruction from the user (step S5), and if there is a patch printing instruction from the user, the patch data is passed to the output device 40 by the patch output unit 33, and the output device 40 is output. Thus, the measurement patch is printed (step S6). The printed patch is measured by the patch measurement unit 39 (step S7), and the measured value is converted into the CMYK color space by the color space conversion unit 34 to be the reference color data (step S8). This reference color data is stored in the secondary storage device 50 (step S
9), and then CMY extracted by the color data extraction unit 31
The K color data and the print data developed by the analysis unit 23 are stored in the secondary storage device 50 (steps S10 and S).
11). If it is determined in step S2 that there is no patch creation instruction, the process proceeds to step S11, and only the print data is stored in the secondary storage device 50. If there is a patch creation instruction but no patch printing instruction in the determination in step S5, the process proceeds to step S10,
Only the CMYK color data and print data are stored in the secondary storage device 50.

FIG. 4 is a diagram showing a measurement patch output from the output device. The measurement patch 41 is output by the output device 4 based on the patch data created by the patch creation unit 32.
It is output from 0. In the patch creation section 32,
The CMYK color data table created by the color data extraction unit 31 is read to create measurement patch data.
In this example, 144 columns of patch data of 6 columns × 24 rows are created. When the patch creating unit 32 creates patch data and the number of colors used in the CMYK color data table is more than 144 colors, the distance to a certain two colors is calculated from the sorted table. Therefore, the representative color is selected to be 144 colors.

FIG. 5 is a diagram showing an example of the structure of color data stored in the secondary storage device. The CMYK color data and the reference color data stored in the secondary storage device 50 along with the print data developed by the analysis unit 23 are numbered as shown in the figure, and the CMYK value of the CMYK color data is assigned to each number. And the CMYK values of the reference color data are stored in the form of a binary set. The C, M, Y, and K color data take values from 0 to 256, respectively. There is no standard color data for data that is out of the representative colors. If the user does not give an instruction to create a patch, the reference color data is not created together with the CMYK color data, and only the print data is saved in the secondary storage device 50.

FIG. 6 is a flow chart showing the procedure of color proofreading when reusing print data. First, the expansion unit 24 extracts the print data of the document stored in the secondary storage device 50 (step S21), expands the print data on the memory 25, and forms an image for one page (step S22). At this time, it is determined whether or not there is a patch printing instruction for color calibration from the user (step S2).
3) If there is a patch print instruction, it is determined whether there is CMYK color data and reference color data saved together with the print data of the document (step S24). If there are CMYK color data and reference color data, the patch creation unit 32 retrieves the CMYK color data and the reference color data acquisition unit 35 retrieves the reference color data from the secondary storage device 50 (step S25). The patch creation unit 32 creates patch data based on the CMYK color data retrieved from the secondary storage device 50 (step S26), and outputs the measurement patch 41 with the output device 40 in the current state (step S27). . The output measurement patch 41 is measured by the patch measurement unit 39, and the color reproduction state of the current output device 40 is measured (step S28). The value measured here is converted from the L ^* a ^* b ^* color space to the CMYK color space in the color space conversion unit 34 (step S29). The difference calculation unit 36 calculates the color difference between the converted CMYK color data and the reference color data extracted in step S25 for each number to obtain adjusted CMYK color data (step S30). The adjusted CMYK color data is stored in the memory 25 by the difference application unit 37 via the expansion unit 24.
The CMYK color data value that is applied to the print data expanded in step S3 and is present in the print data is changed to the adjusted CMYK color data value (step S31). As a result, the print data is calibrated to a color close to the color of the output result of the color-adjusted output device 40, and the output device 40 passes through the output unit 26.
And is printed by the output device 40 (step S3).
2). If it is determined in step S23 that there is no patch printing instruction, and if it is determined in step S24 that there is no CMYK color data or reference color data, the memory 25 is skipped without performing the color calibration procedure.
Output processing is performed based on the print data expanded above.

FIG. 7 is a diagram showing a printing system to which a color proofing apparatus having another structure is applied. According to this color proofing device,
In addition to the configuration of the printing system shown in FIG. 2, a display device 6 for displaying color data extracted from a document
1, a color selecting section 62 for the user to select a specific color from the displayed color data, and a color changing section 63 for changing the selected color to a different color. . The configuration is the same as that of FIG. 2 except for the display device 61, the color selection unit 62, and the color changing unit 63, and thus the details thereof will be omitted.

When outputting the print data stored in the secondary storage device 50, the color data stored together with the print data is taken out and displayed on the display device 61.
With respect to the displayed color data, the user selects the color to be changed through the color selection unit 62 and indicates the changed color. The data of the color to be changed and the data of the color after the change are notified to the color changing unit 63, and the color changing unit 63 notifies the developing unit 2
4, the corresponding color data of the print data expanded in the memory 25 is changed to the designated color data. This allows the user to intentionally change a particular color used in the document to a different color. This color change may be performed independently of the color calibration based on the color data obtained from the patch, or may be used in combination with the color calibration.

Such a specific color change must be output in the same color for corporate colors, for example, but it is useful in such a case. By designating the specific color as the corporate color, it is possible to output the unified corporate color without changing the other colors.

[0024]

As described above, according to the present invention, as a color proofing apparatus for a printing system that stores print data in the secondary storage means, a color data extracting unit for performing color proofing for each document is newly added. In addition, patch data generation means for creating a patch for color measurement based on the color data obtained there, patch measurement means for measuring the output measurement patch to obtain the color reproduction value of the current output means, and printing A means for calculating a difference from the color output at the time of saving the data and a means for applying the difference to the print data are provided.

As a result, when the stored print data is output, the same output as the print result output at the time of storage can be obtained even if the output means changes from time to time when the print data is saved. Therefore, it is possible to realize the correct color reproduction close to the print result by the color-adjusted output means in document units.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle configuration of a color proofing apparatus according to the present invention.

FIG. 2 is a block diagram showing a configuration example of a printing system to which the color proofing apparatus of the present invention is applied.

FIG. 3 is a flowchart showing a flow when saving print data.

FIG. 4 is a diagram showing a measurement patch output from an output device.

FIG. 5 is a diagram showing an example of a structure of color data stored in a secondary storage device.

FIG. 6 is a flowchart showing a procedure of color calibration when reusing print data.

FIG. 7 is a diagram showing a printing system to which a color proofing apparatus having another configuration is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 analysis means 2 secondary storage means 3 output means 4 color data extraction means 5 patch data generation means 6 patch measurement means 7 difference calculation means 8 difference application means 10 external device 20 print control device 21 reception unit 22 spool unit 23 analysis unit 24 Development unit 25 Memory 26 Output unit 31 Color data extraction unit 32 Patch creation unit 33 Patch output unit 34 Color space conversion unit 35 Reference color data acquisition unit 36 Difference calculation unit 37 Difference application unit 38 Instruction unit 39 Patch measurement unit 40 Output device 50 Secondary storage

Claims (3)

[Claims] 1. A color proofing apparatus for a printing system, comprising a secondary storage means for storing print data of a document for reuse, wherein printing is performed from data described in a page description language from an external device. Color data extracting means for extracting color data included in the print data that has been expanded as possible, patch generating means for generating patch data for printing based on the extracted color data, and Patch measurement means for measuring the patch output from the output means by the patch data, and storing the color data obtained by the measurement together with the print data and the color data in the secondary storage means as reference color data, A patch output based on the color data stored with the print data when the print data stored in the secondary storage means is reused Difference calculation means for calculating the difference between the measured data obtained from the above and the reference color data stored together with the color data, and the difference calculation means for the print data sent to the output means for reuse. And a difference applying unit that performs color calibration by applying the difference calculated by 2. An instruction unit for selecting whether or not to save the color data and the reference color data associated with the print data according to an instruction from a user. The described color proofing device. 3. Display means for displaying color data extracted from the document, color selection means for selecting a specific color from the display means, and color changing means for changing the selected color to a different color. The color proofing apparatus according to claim 1, further comprising: