JP2006209407A - Remote calibration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to detect errors at an adequate level for each job at a remote origin both to avoid useless output and to enable calibration with precision which a user wants when a color printer at a remote destination is remotely controlled to automatically execute calibration. <P>SOLUTION: An error detecting level is changed for each job by switching a threshold value table for each job or by setting up an allowable degree for each job. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for calibrating a remote printer by remote control in order to obtain a stable output when outputting to a color printer via a network such as the Internet or an intranet.

  In recent years, in the digitization of the process of creating printed materials, color printers that calibrate and output directly from electronic data have appeared, and for color printers at remote locations, in order to reduce costs related to delivery of output materials, There is a need to output data directly by remote control. In that case, it is essential to calibrate the color printer so that the same output result is always output stably. Patch output is performed at the remote location, and the result is sent to the scanner and density of the color copier. A technique for manually performing calibration using a meter is often used. Further, a method for automatically performing the calibration process as described above has been proposed.

As another conventional example, Patent Documents 1 to 3 can be cited.
JP 2002-254710 A JP 2002-290762 A JP 2001-324846 A

  In the above proposal, a preset value is used as a threshold value for error detection, and the error detection level is not changed for each job.

  The present invention is characterized in that the level of error detection is changed for each job by switching the threshold table for each job or setting the tolerance for each job.

  When automatically calibrating by remotely controlling a remote color printer, it is possible to detect errors at an appropriate level for each job at the remote source by switching the threshold value table and tolerance of the read data for each job. Thus, useless output can be avoided and calibration with accuracy desired by the user can be performed.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a network system according to an embodiment of the present invention.

  As shown in FIG. 1, the network system according to the present embodiment is firstly composed of a remote network system called Site A and Site B connected by a large-scale network such as WAN. Site A is composed of client A (including a PC and a monitor).

  On the other hand, the site B includes a front-end server 1 serving as a printer controller, a printer engine 2 (connected to the network by the front-end server), and a client B (including a PC and a monitor). The client A and the client B have a CPU / VRAM and the like necessary for monitor display and image processing, and a communication function necessary for communication on the network.

  FIG. 2 is a diagram showing the configuration of the front-end server 1 and the printer engine 2 described above.

  As shown in FIG. 2, the front-end server 1 analyzes a network I / F (interface) unit 10 for connecting to a network, a job control unit 11 for controlling job data, and a PDL (page description language) to obtain intermediate data. The generated PDL interpreter unit 12, the intermediate data storage unit 13 in which intermediate data generated by the PDL interpreter unit is stored, the communication interface unit 14 for exchanging data with the printer engine 2, and the intermediate data storage unit are stored. A rendering unit 15 that converts the intermediate data into bitmap image data, a color management processing unit 16 that performs color matching and calibration processing specified for the job, and a profile storage unit that stores profiles used for color matching 16A, carry Calibration data, a calibration one-dimensional LUT (Look Up Table) storage unit 16B for storing a one-dimensional LUT, a patch data storage unit 17 for storing patches used for calibration data creation, and a calibration management unit 18 Threshold DB (database) 18A for storing a threshold table for detecting color sensor read data errors, error detection unit 18B for detecting color sensor read data errors, tolerance 18C, data read by the color sensor Is stored in the read data storage unit 19.

  The job control unit 11 includes a job management unit 11A that performs management such as holding a job, and a job analysis unit 11B that analyzes a job ticket in the job.

  The printer engine 2 is read by the communication I / F unit 20 that exchanges data with the front-end server 1, the output unit 21, the color sensor control unit 22 that controls the color sensor, the color sensor 23 that reads the patch output, and the color sensor. It comprises a read data storage unit 24 in which data is stored.

  FIG. 3 shows that job data is composed of job ticket data in which contents for instructing processing to a job are described, and job data files that are actual data such as PDF, PS, TIFF, JPEG, and the like. Is shown.

  FIG. 4 shows an example of job ticket data. Here, the layout information includes paper size setting information, paper type information, page orientation information, and the like. The color management information includes RGB and CMYK source profiles, printer profiles, calibration settings, and the like.

  FIG. 5 shows an example of patch data used when creating a calibration.

  In this case, the patch data has different gradations of single colors of C, M, Y, and K, and is used when a calibration method described later with reference to FIG. 7 is executed.

  FIG. 6 shows an example of multi-order color patch data used when creating a calibration. This is patch data with different combinations of C, M, Y, and K values, and is used when executing the calibration method described later in FIG.

  FIG. 7 shows the relationship between the correction curve, device characteristic, and target characteristic when correcting the one-dimensional LUT by calibration, and the calibration data is one-dimensional LUT data indicating the correction curve.

  FIG. 8 is a diagram showing a flow of processing of image data. When RGB data, CMYK data, Lab data, or the like is input, color matching is performed through a source profile and a printer profile, and then the data is passed through a calibration one-dimensional LUT and output as corrected CMYK data. When outputting the patch data, the color matching process is turned off or the one-dimensional LUT process is turned off according to the contents of the patch data.

  FIG. 9 is an example of a color sensor (density sensor) used in the present proposal. A color sensor (density sensor) as shown in FIG. 9 of JP-A-2001-324846 may be used. The color sensor (density sensor) 25 is built in a light emitting element 24A such as an LED and a light receiving element 24B such as a photodiode or CdS in a holder 25C. The density sensor 25 measures the density of the patch T by irradiating the patch T on the transfer belt 26 with light from the light emitting element 25A and receiving the reflected light from the patch T with the light receiving element 24B.

  FIG. 10 is a read data table showing R, G, and B values for each patch. The patch to be read is indicated by a pointer, and when the reading is completed, the pointer is advanced to the next patch.

  FIG. 11 is an RGB value threshold table used in the first embodiment. A threshold table corresponding to the job content is selected for each job. The median and σ are set for each of R, G, and B for each patch, and for the patch with the number pointed to by the pointer, the tolerance 18C set for each job whether the read data is within the threshold is used. To check. Once checked, the pointer is advanced to the next patch.

  FIG. 14 is a flowchart for explaining the steps of the embodiment using the configuration of FIG.

  In step 100, the job data is transmitted from the client A to the front end server 1 through the network, and the process proceeds to step 101.

  In step 101, the job control unit 11 controls, the job data is temporarily held in the job management unit 11A, the job file data processing is set in a standby state, and the process proceeds to step 102.

  In step 102, only the job ticket data is extracted from the job data, and the process proceeds to step 103.

  In step 103, the job ticket data is analyzed by the job analysis unit 11B, and the process proceeds to step 104.

  In step 104, the information on the paper type to be output in the job ticket data in FIG. 4 is set in Info_media, and the flow advances to step 105.

  In step 105, the calibration setting information shown in FIG. 4 is extracted, and it is checked whether or not the calibration is performed remotely. If the setting is not to be performed, the process proceeds to step 110, and the held job data is output using the existing calibration data that is not remote, and the process ends.

  In the case of implementation, the process proceeds to Step 105.5, and a threshold value table and tolerance are set according to the job settings and contents. For example, there is a method of setting the tolerance depending on the data such as setting the tolerance with a job ticket or increasing the tolerance if the data to be printed is text, and reducing the tolerance if the data is a photo image.

  Next, the process proceeds to step 106 where patch data is output and simultaneously read by the color sensor or colorimeter, and the process proceeds to step 107. Here, as shown in FIG. 8, when patch data is output, the CMM and the calibration one-dimensional LUT are turned OFF according to the contents of calibration.

  In step 107, an error check is performed to determine whether the read data in step 106 is appropriate. This detailed processing will be described later in detail with reference to FIGS.

  In step 108, it is determined whether an error has been found in step 107. If there is an error, the process proceeds to step 111 to notify the client A that there is an error, and the process is terminated without outputting the job. If there is no error, the process proceeds to step 109.

  In step 109, calibration data is created based on the read value of the patch data, and the process proceeds to step 110. In step 110, the held job data is output using the calibration data created in step 109, and the process ends.

  FIG. 15 shows a flowchart of the detailed processing in step 106.

  First, in step 200, the patch data is extracted from the patch data storage unit 17, and the process proceeds to step 201.

  In step 201, it is determined whether or not the patch data has been rendered (expanded into bitmap data).

  If it has not been rendered, the patch data is analyzed by the PDL interpreter unit 12 in step 202 to generate intermediate data, and the process proceeds to step 203.

  Next, in step 203, the intermediate data generated in step 202 is temporarily stored in the intermediate data storage unit 13, and the process proceeds to step 204.

  In step 204, the intermediate data stored in step 203 is extracted, and the flow processing at the time of outputting the patch data shown in FIG. 8 is applied by the color management processing unit 16, and the process proceeds to step 205. Color matching and calibration data are processed by appropriately switching ON / OFF according to the contents of the patch data.

  Subsequently, in step 205, the intermediate data in step 204 is developed into bitmap image data by the rendering unit 15, and the process proceeds to step 206.

  In step 206, the developed bitmap image data and Info_media information are transferred to the printer engine 2 and the process proceeds to step 207 in FIG.

  In step 207, the Info_media information is referred to, a paper is selected based on the information, and the process proceeds to step 208.

  In step 208, the patch data is printed on the selected paper, and the process proceeds to step 209.

  Subsequently, in step 209, the printed patch data is read by the color sensor 23 under the control of the color sensor control unit 24, the read data is stored in the read data storage unit 24, and the process proceeds to step 210.

  In step 210, the read data is transferred to the front-end server 1, and the process proceeds to step 211.

  In step 211, the data is transferred to the read data storage unit 19 on the front end server 1 side, and the patch data output process is terminated.

  FIG. 17 shows a flowchart of detailed processing in step 107.

  In step 300, the error flag is set to OFF as an initial value, and the process proceeds to step 301.

  In step 301, a pointer is set at the head of the read data table as shown in FIG.

  In step 302, a pointer is also set at the head of the threshold data table as shown in FIG.

  In step 303, the total number of patches is m, and the process proceeds to step 304.

  In step 304, the initial value 1 is substituted into the counter i.

  In step 305, the Red value of the read data is held in Ri, and the process proceeds to step 306.

  In step 306, the absolute value of the difference between Ri and the median value of Red in the threshold data table is substituted into dR.

  In step 307, it is checked whether dR is equal to or smaller than the value obtained by multiplying the σ of Red in the threshold data table by the tolerance. If No, the process proceeds to step 315 in FIG. 18, where the error flag is turned on and the process is terminated. If yes, go to step 308.

  In step 308, the green value of the read data is entered in Gi, and the process proceeds to step 309.

  In step 309, the absolute value of the difference between Gi and the median value of Green in the threshold data table is substituted into dG.

  In step 310, it is checked whether dG is equal to or less than a value obtained by multiplying Green σ in the threshold data table by the tolerance. If No, the process proceeds to step 315 in FIG. 18, where the error flag is turned on and the process is terminated. If Yes, the process proceeds to step 311 in FIG.

  This will be described with reference to FIG.

  In step 311, the blue value of the read data is held in Bi, and the process proceeds to step 312.

  In step 312, the absolute value of the difference between Bi and the median value of blue in the threshold data table is assigned to dB.

  In step 313, it is checked whether dB is equal to or less than a value obtained by multiplying the blue σ of the threshold data table by the tolerance. If it is No, it will progress to step 315, will set an error flag to ON, and will complete | finish a process. If yes, go to step 314.

  In step 314, if the counter i is greater than or equal to the total number m of patches, the process ends. If so, go to step 316.

  In step 316, the counter i is incremented by 1, and the process proceeds to step 317.

  In step 317, the read data and threshold data table pointers are also incremented by one, and the process returns to step 305 in FIG. This series of processing is repeated until the counter i reaches the total number m of patches.

  19 and 20 show a flowchart of the detailed processing in step 109. Here, as the calibration data, a one-dimensional LUT may be generated as shown in FIG. 19, or the profile may be corrected as shown in FIG.

  First, a method for generating the one-dimensional LUT in FIG. 19 will be described.

  In step 400, read data is extracted from the read data storage unit 19 of the front-end server 1, and the process proceeds to step 401. Here, the read data is RGB data.

  In step 401, the read data is converted into C, M, Y, and K density data, and the process proceeds to step 402.

  In step 402, CMYK one-dimensional LUT calibration data is generated by the algorithm shown in FIG.

  In step 403, the calibration data generated in step 402 is set in the CMYK one-dimensional LUT of the color management processing unit 16, and the process ends.

  Next, the printer profile correction method shown in FIG. 20 will be described.

  In step 500, read data (RGB) is extracted from the read data storage unit 19 of the front-end server 1, and the process proceeds to step 501.

  In step 501, the printer profile is extracted from the profile storage unit 16A, and the process proceeds to step 502.

  In step 502, the read data (RGB) is converted into XYZ data by 3 × 3 matrix operation, and the process proceeds to step 503.

  In step 503, the XYZ data converted in step 502 is converted into Lab data by a predetermined conversion formula, and the process proceeds to step 504.

  In step 504, the printer profile is corrected based on the Lab data, the printer profile is set, and the process ends.

  FIG. 21 shows a flowchart of detailed processing in step 110.

  First, in step 600, the processing of the job file held in the job management unit 11A is resumed.

  In step 601, the PDL interpreter unit 12 analyzes the job file data to generate intermediate data, and the process proceeds to step 602.

  In step 602, the intermediate data generated in step 601 is stored in the intermediate data storage unit 104, and the process proceeds to step 603.

  In step 603, a normal flow for performing color matching and calibration processing on RGB and CMYK data in the color management processing unit 16 is applied to the intermediate data stored in the intermediate data storage unit 104 in step 604. Proceed to

  In step 604, the intermediate data in step 603 is developed into bitmap image data by the rendering unit 15, and the process proceeds to step 605.

  In step 605, the developed bitmap image data is transferred to the printer engine 2, and the process proceeds to step 606.

  In step 606, a sheet is selected based on the Info_media information, and the process proceeds to step 607.

  In step 607, printing is performed on the selected paper, and the process ends.

  As described above, in the calibration data generation by remote control, the tolerance set by the job calibration assurance level determined by analyzing the job ticket setting specified by the user and the contents of the job data for each job. If an error is found by performing an error check according to the error, the error is notified to the client PC, and the specified job data is not output according to the calibration guarantee level for each job. It becomes possible.

[Other embodiments]
Next, another embodiment will be described.

The difference from the above embodiment is that FIG. 11 is replaced with the threshold value table of FIG. That is, the difference is whether it has an RGB value as a threshold value, an L ^* a ^* b ^* value, or a CMYK density value.

The L ^* a ^* b ^* value has a threshold value when the color sensor of the printer engine 2 is replaced with a colorimeter. The CMYK density value has a threshold value when the color sensor of the printer engine 2 is assumed to be a density sensor or a density meter. Alternatively, a value calculated by color space conversion from the measured value may be used.

FIG. 12 is a threshold table for L ^* a ^* b ^* used in another embodiment. Median L ^* , a ^* , b ^* values and σ are set for each patch.

  FIG. 13 is a threshold table of CMYK density values used in another embodiment. For each patch, a median and σ are set for each C, M, Y, and K density value.

Which of these values is held as a threshold table may be set by user designation. When the threshold value is given by the L ^* a ^* b ^* value or the CMYK density value, the read data table also has the L ^* a ^* b ^* value and the CMYK density value. Also, in the error check processing flow of FIGS. 17 and 18, it is necessary to replace the value to be evaluated with the L ^* a ^* b ^* value and the CMYK density value.

FIG. 23 is a flowchart of error check processing in the case of L ^* a ^* b ^* .

  Since Step 800 to Step 804 are the same as Step 300 to Step 304, description thereof will be omitted.

In step 805, the color difference between the L ^* a ^* b ^* value of the read data and the median L ^* a ^* b ^* value of the threshold data table is calculated and substituted into dE.

  In step 806, it is determined whether dE is equal to or smaller than a value obtained by multiplying σ in the threshold data table by the tolerance set for each job. If it is No, it will progress to step 810 and will complete | finish by setting an error flag to ON. If yes, go to step 807.

  In step 807, it is determined whether i is smaller than m. If yes, go to step 808.

  In step 808, 1 is added to i.

  In step 809, 1 is added to each of the pointers of the reading data table and the threshold data table, and the process proceeds to step 805.

  In this embodiment, a color sensor (RGB) is taken as an example of the output patch reading means, but a densitometer or a colorimeter capable of measuring chromaticity can be used instead.

  In the present embodiment, remote calibration control and execution processing are performed in the front-end server connected to the printer engine, but the same is possible in the case of a built-in controller type incorporated in the printer engine. This is because the processing function of the front-end server can be incorporated into the built-in controller.

  Another embodiment will be described with reference to FIG. FIG. 22 is a flowchart of another embodiment when the remote calibration setting is ON.

  In step 701, confirmation patch data, a threshold table, and tolerance are set according to the job contents. The confirmation patch data is used to determine whether or not the job can be executed using the current profile or calibration table as is. The patch is selected according to the job and its calibration method, and color matching is performed. Also, ON / OFF of the one-dimensional LUT process is appropriately selected to generate patch data. The threshold table and tolerance are also set appropriately according to the calibration assurance level for each job.

  In step 702, the set patch data for confirmation is printed as in the flow described with reference to FIGS.

  In step 703, an error check is performed as described with reference to FIGS.

  In step 704, an error flag is determined. If the error flag is OFF, the current profile and calibration data are used as they are, and there is no problem, so the process proceeds to step 710 and the job data is output and the process ends. If the error flag is ON, calibration needs to be performed, and the process proceeds to step 705.

  Steps 705 to 711 are the same as steps 105.5 to 111 in FIG.

  According to this embodiment, according to the calibration guarantee level for each job, it is determined whether or not the current profile or calibration table can be used as it is. There is an effect that the processing efficiency can be increased. Further, by omitting calibration, it is possible to reduce the probability of failure such as erroneous calibration due to factors such as measurement errors.

It is a figure which shows the structure of the network system by one Example of this invention. 2 is a diagram illustrating a configuration of a front-end server 1 and a printer engine 2. FIG. It is a figure which shows the internal structure of job data. It is a figure which shows the internal structure of job ticket data. It is an example (CMYK primary color) of patch data used for calibration. It is an example of a multi-color patch chart of CMYK mixed colors. FIG. 10 is a conceptual diagram of processing for creating a CMYK primary color LUT in step 107; It is a flowchart of a color management process. It is an example of a color sensor (density sensor) used in the present invention. It is a figure which shows the table of RGB value of reading data. It is a figure which shows the threshold value table of RGB of read data. It is a figure which shows the threshold value table of L ^* a ^* b ^* of the read data in another Example. It is a figure which shows the threshold value table of the CMYK density | concentration of the read data in another Example. It is a flowchart of the main process of this invention. 7 is a flowchart showing details of patch data output in step 106; 7 is a flowchart showing details of patch data output in step 106; 10 is a flowchart showing details of error check processing in step 107; 10 is a flowchart showing details of error check processing in step 107; As the calibration data generation in step 109, a detailed processing flowchart for generating a CMYK one-dimensional LUT is shown. As the calibration data generation in step 109, the detailed processing flowchart for correcting the profile is shown. A detailed processing flowchart for outputting job data in step 110 is shown. The flowchart which shows the process by the remote calibration setting ON in another Example. The flowchart which shows the error check process of another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Network I / F part 11 Job control part 11A Job management part 11B Job analysis part 12 PDL interpreter part 13 Intermediate data storage part 14 (front end server 1) Communication I / F part 15 Rendering part 16 Color management processing part 16A Profile storage Part 16B Calibration one-dimensional LUT
17 Patch Data Storage Unit 18 Calibration Data Generation Unit 18A Threshold DB
18B error detection unit 18C tolerance 19 (front end server 1) read data storage unit 20 (printer engine 2) communication I / F unit 21 output unit 22 color sensor control unit 23 color sensor 24 (printer engine 2) read data storage unit 25 Concentration sensor 25A Light emitting element 25B Light receiving element 25C Holder 26 Transfer belt

Claims (10)

In a remote calibration method of a remote proofing system for outputting a color image to a printer connected via a network,
A step for providing remote calibration execution information in the job data;
Analyzing the information and outputting patch data to a remote engine;
A reading step of automatically reading the patch output result;
Setting a threshold value of read data read in the step for each job;
Comparing the threshold with read data to detect an error;
Notifying the remote source client PC of the result of the error detection;
A remote calibration method comprising a step of controlling calibration application to job data based on the notification result.   The remote calibration method according to claim 1, wherein when an error is detected as a result of the error detection, job output is stopped.   2. The remote calibration method according to claim 1, wherein the job includes job ticket data and a job data file, and the remote calibration execution information is included in the job ticket data.   2. The remote calibration method according to claim 1, wherein the output patch is stored in a printer front-end server or a built-in printer controller.   2. The remote calibration method according to claim 1, wherein the output patch is a plurality of C, M, Y, K primary color patch charts or a C, M, Y, K mixed color patch chart. .   The remote calibration method according to claim 1, wherein an RGB output color sensor, colorimeter, or densitometer is used in the reading step.   2. The remote calibration method according to claim 1, wherein the calibration data is obtained by correcting a C, M, Y, K one-dimensional LUT or a multi-dimensional LUT format printer profile.   2. The remote calibration method according to claim 1, wherein the threshold value of the read data is constituted by a threshold value table including a median value and σ, and error detection is performed by setting a threshold value table and tolerance for each job.   The remote calibration method according to claim 1, wherein the error detection is performed by a printer front-end server or a built-in printer controller.   2. The method according to claim 1, wherein whether or not the current profile or calibration table is within an allowable range is checked based on a determination criterion set for each job, and if it is within the allowable range, new calibration is not executed. Remote calibration method.

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