JP2007060396A - Calibration method and calibration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain optimal calibration method in color calibration under environment where various kinds of proof printers and measuring instruments for calibration are mixed. <P>SOLUTION: An operator is enabled to confirm conditions of the proof printers between bases and to select processing content by adding model information of the proof printers and information about a measurement means for calibration to print data and transmitting the print data. Thus, when conditions are compatible, a first base and calibration target characteristics are aligned and highly precise matching of printing results at each printing base becomes possible. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a calibration method and a calibration system using a printer. In particular, the present invention relates to a calibration method and a calibration system that are effective in a work process when a plurality of printers perform color tone confirmation on the same data.

  In a printing process, before printing by a printing machine, a pre-printing process (hereinafter also referred to as a prepress process) that is a process related to typesetting, plate making, and printing plate is often performed.

  The prepress process is performed in order to confirm the quality of the printed matter to be printed, and ideally, the printed matter to be finally printed can be confirmed at the stage of the prepress step.

  In the pre-press process, various checks of the printed matter to be printed are performed. Among them, color tone confirmation is one of the important elements. This is because each of the input / output devices to be used has different color characteristics and reproduction regions, so that the print results are slightly different colors.

  Therefore, color tone confirmation is performed in order to correct different colors, and print data submitted using a proof printer is printed as a simulation of actual printing. In many cases, the output result of printing is used as a color tone reference, and output adjustment of a printing machine that finally performs printing is performed.

  What is important here is the color matching of the output results from the proof printers of the submission source and the submission destination. Since the print results from the production printers at both printing bases are the same, as long as the print results from the proof printer at the submission destination are possible, they can be reproduced in the same color as the print results from the proof printer at the submission source. It is desirable that it is adjusted so that.

  As a conventional technique related to this color adjustment, there is an example of managing color differences of a plurality of color management systems existing in a remote place. This is because information on brightness, color, and gamma characteristics is sent to a remote monitor over the network, and the information is read at the remote location to check the color difference between the information sender and receiver, and between remote systems. Is minimized (for example, Patent Document 1).

  In many cases, proof printers are color-managed so as to simulate a predetermined printing machine, so that a print result having the same color tone can be obtained as much as possible at the submission source and the submission destination.

  However, when trying to simulate the same printing press with a plurality of proof printers, the type of proof printer and the characteristics of the ink may differ, and the color tone upon output may differ. If this is noticeable, printing may not be performed with the color tone expected in actual printing, which may cause a problem. Such a problem can be avoided by using a proof printer of the same model at the submission source and the submission destination to a certain extent.

  However, even with the same model, color differences may occur due to differences in machine conditions and environmental conditions. In addition, it is not practical that a plurality of submission sources use the same type of proof printer, and it is not realistic to arrange proof printers of the same model as the submission source at all submission destinations.

  Therefore, the printing system used at the time of proofing to cope with these problems absorbs output color fluctuations due to factors such as individual differences among models, environmental changes, and long-term changes over time, and the uniformity and stability of output results. Many of them have a calibration function for securing the method.

  In this calibration, based on the target characteristics (hereinafter also referred to as calibration target characteristics) that are output using a spectrocolorimeter, densitometer, scanner, etc., calibration is performed by calculating differences in color, density, and chart printing results. Correction data is calculated to make the output result uniform.

  As an example of uniformly calibrating the output of such a plurality of devices, an example is disclosed in which another tester is calibrated with respect to a plurality of testers using the adjusted output signal as a reference ( For example, Patent Document 2).

JP 2000-292262 A Japanese Patent Laid-Open No. 10-221406

  However, settings may differ depending on the type of proof printer, the software used, the contents of print data, and the like. Therefore, even if the calibration target setting, which is a reference of one proof printer, is used for calibration of another proof printer, the color tone of the output result may not be reproduced in the same manner.

  For example, if you do not calibrate a printer that can print at a sufficiently high density and set the calibration characteristics according to its capabilities, the output results will differ due to differences in models and individual differences There is. In other words, if the calibration characteristics are used with a printer having a lower maximum density, even if the same data is output, the color tone of the high density portion cannot be sufficiently reproduced, and the color calibration results after calibration differ.

  Also, the measured value may differ depending on the spectrocolorimeter or densitometer model used for measurement. That is, even if the calibration target characteristic of a proof printer is used as the target characteristic of another proof printer, the color tone will differ as a result of calibration if the model of the measuring instrument is different.

  Accordingly, the present invention has been made in view of the above problems, and provides a calibration method for minimizing the color difference of the printing result of each printer in color calibration in an environment where printers of various models coexist. With the goal.

  Therefore, the present invention includes a first calibration step for calibrating the first pudding based on the first calibration target characteristic, and a second calibration step for calibrating the second printer, Whether or not to use the first calibration target characteristic is determined based on calibration information that is a condition for executing the first calibration step, and the calibration information is within a predetermined same range. And a second calibration step of performing calibration of the second printer based on the calibration target characteristic.

  According to the present invention, the calibration target characteristic and the calibration information set in the calibration process at the first base (submission source) are associated with the print data and sent to the second base (submission destination). To do. When the transferred calibration information meets a predetermined condition, the transferred calibration target characteristic is set as the calibration target characteristic at the second base. As a result, a uniform color can be reproduced at different locations, and it is not necessary to attach output paper, leading to cost reduction. Further, it is not necessary to perform color matching each time while looking at the output paper for each process, so that there is no waste of work and it is possible to increase efficiency.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing an outline of a printing color proofing system according to an embodiment of the present invention.
The color proofing system according to the present embodiment includes proof printers each having a calibration function at each of the first printing base and the second printing base. Based on the printing results of these proof printers, color adjustment of printing press output and the like are performed. Do. The first printing base further includes a personal computer (hereinafter also referred to as a PC) 1 that controls printing by a proof printer. The second printing base also includes the same PC 3. These PCs perform processing related to calibration of the proof printer and data transmission / reception processing described later with reference to FIG.

  FIG. 2 is a flowchart showing processing relating to calibration of the proof printer according to the present embodiment.

  First, in step (101), a calibration target characteristic for the proof printer 2 is set at the first printing base which is the submission source. This calibration target characteristic indicates the correspondence between the input density data for each ink color of CMYK and the output density data corresponding thereto. More specifically, it is numerical information indicating what density characteristics the CMYK ink color patch data should be finally output as shown in FIG. For example, when the patch data is a chart of the form as shown in FIG. 3, the input values (0, 10, 20,..., 100) of each row (C, M, Y, K) and each column in the figure are shown. Information on the density at which all corresponding patches should be output is the calibration target characteristic.

  For setting the calibration target characteristics, it is not always preferable to set characteristics that exhibit the full capability of the printer. For example, if a calibration density characteristic is set in accordance with the ability of a printer that can perform printing at a sufficiently high density, a difference in output results occurs due to the influence of different models or individual differences. In other words, in the case of a printer with the highest density lower than that, even if the same data is output, the color tone of the high density portion cannot be reproduced, and the color calibration results after calibration differ. Therefore, it is desirable to set the calibration target characteristics to be set in the printer 2 in consideration of the characteristics of the proof printer, the contents of the print data, and the final printing machine capability.

  Next, in step (102), calibration is actually performed using the calibration target characteristics set in step (101) to generate calibration correction data.

  FIG. 4 is a flowchart showing a detailed procedure of calibration. In step (201), patch data is printed out from the printer 2 based on the input density data of the calibration target characteristics. In step (202), the patch data output in step (201) is measured. In this embodiment, this measurement is performed using a densitometer.

  In step (203), calibration correction data is generated by a known calculation method based on the output density of the calibration target characteristic and the patch measurement result acquired in step (202). Specifically, for the input density data, a γ correction data table is generated or selected so that the output density of the target characteristic can be obtained. Next, in step (204), the calibration correction data generated in step (203) is stored in a predetermined memory so that it can be used in subsequent printing. In the configuration in which the printer performs gamma correction, the generated calibration correction data is set in the memory of the printer main body. Alternatively, calibration correction data is set in a predetermined area such as a hard disk in a configuration in which γ correction is performed by a personal computer. The calibration for the proof printer 2 at the first site is thus completed.

  Referring again to FIG. 2, in step (103), printing by the first printer is performed on predetermined print data for performing color calibration. Here, printing is performed with the printer output corrected using the calibration correction data generated in step (102).

  The operator confirms whether the output product printed at this point is printed with a desired color. If there is a problem, process / correct the contents of the print data and print again. If it is confirmed that there is no problem in the color of the printed output result, the process proceeds to step (104).

  In step (104), transfer data is generated in order to send the print data whose color has been confirmed to the second print base as the submission destination.

  Here, in correspondence with the print data, the calibration target characteristic data set in step (101) and the calibration information are added to form the data for sending.

  Here, the calibration information includes model information of a measuring device such as a densitometer used for patch measurement in step (102) and printer model information used in step (103). In step (105), the data generated in step (104) is sent to the second printing base. In this embodiment, electronic transfer is performed via a network. The print data may be sent physically by storing the data in a recording medium such as a floppy (registered trademark) disk.

  It should be noted that the format of recording or transfer may be any format as long as the correspondence relationship between the calibration target characteristics and the calibration information included in the print data can be uniquely specified. For example, all the data may be combined as a single file according to a predetermined rule, or data representing their corresponding relationship may be separately transferred as separate data.

  In contrast to the above-described processing related to calibration by the PC 1 at the first printing base, the PC 3 at the second printing base performs the following processing for sending print data.

  That is, in step (106), the data sent from the first printing base is received at the second printing base which is the submission destination, and the content is checked. Specifically, it is inspected whether the calibration information satisfies a predetermined condition.

  FIG. 5 is an example of a flowchart showing a procedure for determining whether the calibration information satisfies a predetermined condition.

  In step (401), referring to the printer model information added to the transferred data, it is checked whether it is the same as the printer model used at the second printing base. If (402) is different, it is determined that “the condition is not satisfied”.

  It should be noted that this is not the case when the conditions of the devices are strictly the same. For example, if the devices have similar specifications, the calibration information based on the devices may be in the same range.

  In step (402), referring to the model information of the measuring instrument added to the transferred data, it is checked whether it is the same as the model of the measuring instrument used at the second printing base. It is determined that “the condition is satisfied”, and when it is different, it is determined that “the condition is not satisfied”.

  If it is determined that “the condition is satisfied”, the process proceeds to step (107) in FIG. 2, and the calibration target characteristic added to the transfer data, that is, the calibration of the printer 2 at the first site is used. Set the same calibration target characteristics.

  If it is determined that “the condition is not satisfied”, the process proceeds to step (108), and a predetermined calibration target characteristic is set. That is, an appropriately defined calibration target characteristic is set according to the printer at the second printing base and the measuring device to be used.

  In step (109), calibration is performed to generate correction data. The method of generating calibration correction data is the same as that described with reference to step (102) and FIG.

  In step (110), the transferred print data is printed by the second printer. Here, printing is performed with the printer output corrected using the calibration correction data generated in step (109), that is, the γ correction table.

  Here, the operator confirms the color of the printed output and uses the output result as a reference for the printing press.

  In this way, the calibration target characteristics are associated with the print transfer data, and the model information of the proof printer and the information of the calibration measuring means are associated with each other, whereby the submission source (first printing base) and the submission destination (second printing base). ) Can determine the suitability of the proof condition in the submission destination. Furthermore, if the conditions are met, the calibration target characteristics can be aligned with the first base, so the output characteristics of the printer between the two bases can be aligned with high accuracy, and accurate proof output is possible. Become.

  In addition, when the conditions do not match, it is possible to perform normal-precision printing with the proof printer at the second site by using a predetermined calibration target characteristic. Therefore, it is possible to avoid an unexpected decrease in accuracy due to misappropriating calibration target characteristics under different conditions of the proof printer used at the first base with different models or different measuring instruments.

  In addition to the printer model information, information to be added in association with the print data includes information on items that need to be set at the time of printing, such as the type of media used in the proof and the print quality setting mode. Information for print setting may be included in the print base as in the first base.

  The information to be added in association with the print data may include measurement conditions (density measurement status, filter, reference time until measurement after printing, etc.) in addition to the calibration measuring instrument information. Further, the second printing base may include information for calibration with the same settings as the first base.

(Second Embodiment)
The second embodiment according to the present invention relates to an example in which the color proofing method at the second printing base as a submission destination is further improved.

  Until the transfer data is generated at the first printing base and the data is transferred to the second printing base, the processing in the first embodiment (from step (101) to step (105) in FIG. 2) Since it is the same, description is abbreviate | omitted.

  FIG. 6 is a flowchart showing a calibration procedure according to the present embodiment after receiving print data and data associated therewith at the second print base.

  In step (500), the data transferred from the first printing base is received at the second printing base that is the submission destination, and the calibration information is displayed on the display of the PC 3. Here, the calibration information is model information of measuring means such as a densitometer used at the first printing base and model information of the printer.

  In step (501), the operator compares the calibration information with the proof printer configuration at the second site and the contents of the measuring instrument used for calibration, and the calibration target transferred in association with the submitted print data. Select whether to use the characteristic. The criterion here is the same as step (106) in the flowchart of FIG.

  If it is determined that the transferred calibration target characteristic is to be used, the process proceeds to step (502).

  In step (502), the calibration target characteristic data added to the transfer data, that is, the same calibration target characteristic data as used in the first printer is set.

  In step (503), calibration is performed to generate correction data.

  Next, in step (504), the highest density in the second printer obtained by the calibration in step (503) is compared with the calibration target characteristic of the first printer. And then. It is checked for each ink color whether the maximum density of the second printer does not reach the maximum density in the calibration target characteristics or there is a difference greater than a predetermined threshold.

  If it is determined that the second printer has the necessary density for the calibration target characteristic of the first printer, the process proceeds to step (505).

  If the second printer determines that the necessary density for the calibration target characteristic of the first printer is not obtained, the process proceeds to step (506), and the user is warned.

  Here, the user may make a determination to interrupt the subsequent processing. In this case, adjustment / replacement of the second printer, model change, and the like are considered.

  If it is determined that printing is to be performed after checking the warning, the process proceeds to step (505).

  On the other hand, if it is determined in step (501) that the transferred calibration target characteristic is not used, the process proceeds to step (507).

  In step (507), preset calibration target characteristic data is set for the printer used at the second printing base. In this case, similarly to the first embodiment, normal-precision printing can be performed by using the prescribed calibration target characteristics. Then, it is possible to avoid an unexpected decrease in accuracy due to misappropriating calibration target characteristics under different conditions of the proof printer used at the first base with different models or different measuring instruments.

  In step (508), calibration is performed to generate correction data. In this case, since the calibration target characteristics are predetermined for the second printer, it is not always necessary to check the maximum density as in step (504), and the process can proceed to step (505). It is.

  In step (505), the transferred print data is printed by the second printer. Here, using the calibration correction data generated in step (503) or step (508), printing is performed with the printer output corrected. The operator checks the color of the printed output result and uses this result as a reference for the printing press.

  In this way, by adding the model information of the proof printer and the model information of the calibration measuring instrument to the print data and transferring it, the operator can confirm the conditions of the proof printer between the bases and select the processing contents Will be able to. As a result, if the conditions are met, the calibration target characteristics can be aligned with the first base, and high-precision matching of the print results at each print base is possible.

  Further, even if it is not suitable, since it can be output under the predetermined conditions as described above, it is possible to avoid a trouble that the color of the proof output result greatly differs between the bases.

  Also, by transferring the print target data in association with the calibration target characteristic, it is confirmed whether or not the maximum density obtained from the measurement result at the time of executing the calibration satisfies the condition confirmed at the first base. Will be able to. Therefore, it is possible to avoid the trouble that the proof output results between the bases are different.

(Other embodiments)
In each of the above-described embodiments, the form in which the present invention is applied to the calibration of a proof printer for color adjustment of a printing press has been described.

  For example, in a system in which a plurality of printers and a PC are connected via a network, a calibration target characteristic for one printer is transferred to another printer together with calibration information, and the printer performs similar calibration. May be. In such a case, it is clear from the description of each of the above embodiments that the calibration target characteristics and the like do not necessarily have to be sent in association with the print data.

1 is a block diagram showing an outline of a printing color proofing system according to an embodiment of the present invention. It is a flowchart which shows the process regarding the calibration of the proof printer which concerns on this embodiment. It is a figure which shows a chart. It is a flowchart which shows the detailed procedure of a calibration. It is an example of the flowchart which shows the determination procedure whether calibration information is satisfy | filling predetermined conditions. It is a flowchart which shows the procedure of the calibration which concerns on this embodiment after receiving printing data and the data linked | related with it in the 2nd printing base.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Personal computer of 1st site 2 Proof printer of 1st site 3 Personal computer of 2nd site 4 Proof printer of 2nd site

Claims (10)

A first calibration step for calibrating the first pudding based on the first calibration target characteristic;
A second calibration step for calibrating the second printer,
Whether or not to use the first calibration target characteristic is determined based on calibration information that is a condition for executing the first calibration step, and the calibration information is within a predetermined same range. A second calibration step of performing calibration of the second printer based on the calibration target characteristic;
A calibration method characterized by comprising: Printing on the first printer on which the first calibration step has been executed based on the print data;
A step of performing printing based on the print data in a second printer in which the second calibration step is executed based on the first calibration target characteristic;
The calibration method according to claim 1, further comprising:   The calibration target characteristic is based on the correspondence between the input density and the output density, and the maximum output density of the second printer does not reach the maximum density recorded in the sent calibration target characteristic. The calibration method according to claim 1, further comprising a step of prompting the user to give a warning.   In the second calibration step, when the printer model information included in the calibration information is different from the printer model used in the second printing step, the transferred calibration target characteristic is not used. The calibration method according to claim 1, wherein the second calibration is performed using a predetermined calibration target characteristic.   In the second calibration step, when the model information of the measuring instrument included in the calibration information is different from the model of the measuring instrument used in the second calibration step, the transferred calibration target characteristic is used. The calibration method according to claim 1, wherein the second calibration is performed using a predetermined calibration target characteristic. First calibration means for calibrating the first pudding based on the first calibration target characteristic;
A second calibration means for calibrating the second printer,
Whether or not to use the first calibration target characteristic is determined based on calibration information that is a condition for executing the first calibration means, and the calibration information is within a predetermined same range. A second calibration means for calibrating the second printer based on the previous calibration target characteristic;
A calibration system characterized by comprising: Means for printing on the first printer on which the first calibration means has been executed based on the print data;
Means for performing printing based on the print data in a second printer in which the second calibration means is executed based on the first calibration target characteristic;
The calibration system according to claim 6, further comprising:   The calibration target characteristic is based on the correspondence between the input density and the output density, and the maximum output density of the second printer does not reach the maximum density recorded in the sent calibration target characteristic. 7. The calibration system according to claim 6, further comprising means for prompting a user to warn.   In the second calibration means, when the printer model information included in the calibration information is different from the printer model used in the second printing step, the sent calibration target characteristic is not used. The calibration system according to claim 6, wherein the second calibration is performed using a predetermined calibration target characteristic. In the second calibration means, if the model information of the measuring instrument included in the calibration information is different from the model of the measuring instrument used in the second calibration means, the sent calibration target characteristic is used. The calibration system according to claim 6, wherein the second calibration is performed using a predetermined calibration target characteristic.

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