JP2006168200A - Printing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that the operating stability of an output device differs per model with a lapse of time, and to put an appropriate model-wise calibration into practice. <P>SOLUTION: Measurements obtained by a previous calibration and its date are recorded, the operating stability of the output device now in use is calculated from the recorded data, and thereby, an optimal interval between the calibrations is decided automatically. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a calibration method for a printing apparatus, and more particularly to a method for performing calibration at an optimal timing for an output apparatus.

  It is known to perform calibration for adjusting output characteristics of a printing apparatus.

  For example, in Patent Document 1, in a calibration mode, a predetermined test pattern stored in advance is recorded on a recording sheet by the printer unit B, the recording sheet is conveyed to the reader unit A, and a CCD sensor or the like is used. The LUT converts the density characteristics so that the density of the original image and the density of the output image match based on the read image signal and the gradation characteristic information stored as the predetermined test pattern. A configuration for setting data is disclosed.

The conventional calibration apparatus and method outputs a printed calibration patch image at an interval determined in advance by the system such as daily, weekly, and monthly, and measures the density and chromaticity of the patch image. The calibration is performed by using correspondence description data of the output device prepared in advance.
JP 2001-045295 A

  However, the output device has different stability with respect to the elapsed time for each model, and even if the same model is used, there is some variation in stability depending on the machine and color material lot, so it is optimal for the output device being used. There are differences in the calibration interval. For this reason, the calibration interval specified by the system may cause more than necessary calibration or may be insufficient.

  Further, in order to solve the above problem, it is necessary to separately measure the stability of the output device used to calculate the optimum calibration interval, which is very complicated.

  In order to solve the above-mentioned problems, the calibration apparatus and method according to claim 1 of the present invention records the measured value and date when the previous calibration was performed, and uses the output apparatus from the data. It is characterized by calculating the stability of and automatically determining the optimum calibration interval.

  According to the present invention, the measurement value and date / time when the previous calibration was performed are recorded, the stability of the output device used is calculated from the data, and the optimum calibration interval is automatically determined. Therefore, calibration can be performed at an optimum timing for the output device used without the operator being particularly conscious.

  Hereinafter, embodiments of the present invention will be described in detail using specific examples.

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

  FIG. 1 shows an outline of a printing system in an embodiment of the present invention.

  The printing system of the present embodiment basically includes a personal computer (hereinafter simply referred to as “PC”) (101), an inkjet printer (hereinafter also referred to as “printer”) (102) as an output device, and calibration. A densitometer (103) that can be used as a measuring instrument is connected.

  The PC (101), as an information processing apparatus, performs various processes relating to control of a printer (102) and a densitometer (103) as a measuring machine as shown below. The CPU (105) executes the process for the above control according to a program such as the process described later with reference to FIGS. 2 and 3 stored in the storage device (107), and the work memory (106) Used as a work area. An operation unit (hereinafter, also simply referred to as “UI”) (104) serving as a user interface performs processing related to input by the user and display to the user regarding the execution of the above processing, and includes an input device such as a keyboard and a display. . The real-time clock (hereinafter also simply referred to as “RTC”) (108) can acquire the current date and time, the date and time when the printer (102) was calibrated, and the elapsed time since the previous calibration. Used to calculate

  In this printing system, a user can usually output documents, images, and the like processed by various applications on the PC (101). That is, predetermined image processing can be performed on the image and the like processed by the print application in the PC (101), and the print data can be output to the printer (102) for printing. Further, as a feature of the present invention, when calibration patch output is performed, the date and time acquired from the RTC (108) is recorded in the storage device (107) as needed. In this embodiment, the date and time are recorded in the storage device (107) of the PC (101). However, in consideration of connection with the network, a separate storage area is provided in the printer (102), It is also possible to record.

  In the calibration described later with reference to FIG. 3, the densitometer (103) measures the density of a patch as a predetermined measurement image by the calibration program of the PC (101), and the measurement data is stored in the PC (101). input. The PC (101) performs calibration based on this measurement data.

  The storage device (107) stores a patch measurement value and measurement date and time in the previous calibration, and a relational expression between an elapsed time and a fluctuation amount calculated from the data. When calibration has never been performed, an initial value introduced at the time of shipment is stored.

  The relational expression in the present embodiment is configured by a look-up table in which the input value is an elapsed time, and the initial value contains an average relational expression of the target output device as shown in FIG. .

  Calibration processing according to the present embodiment based on the above configuration will be described with reference to the flowcharts of FIGS.

  FIG. 2 shows a calibration interval check process when the printing system is activated and when printing is started. The “allowable fluctuation amount”, which is a necessary parameter at this time, is set by the user via the UI (104) on the setting screen shown in FIG.

  In S201, the previous calibration date and time of the printer (102) is acquired from the storage device (107).

  In S202, the elapsed time is calculated from the date acquired in S201 and the current date acquired from the RTC (108).

  In S203, the expected fluctuation amount is calculated from the elapsed time calculated in S202 and the lookup table acquired from the storage device (107).

  In S204, the allowable fluctuation amount obtained from the storage device (107) is compared with the predicted fluctuation amount calculated in S203. If the expected fluctuation amount exceeds the allowable fluctuation amount, the process proceeds to S205, and if it is lower, the check is performed. Exit.

  An example of the expected fluctuation amount, the allowable fluctuation amount, and the lookup table at this time is shown in FIG. FIG. 7A shows the initial value of the lookup table. If the allowable variation amount at this time is set to 0.05, the next calibration is optimal after 4 days. (b) shows the result of repeated updating of the lookup table to some extent. If the allowable fluctuation amount at this time is also 0.05, it indicates that the next calibration is optimal after 5 days and the initial value is one day earlier. (c) is the case where the allowable variation is set to 0.025 for the lookup table of (b). In this case, the next calibration is optimal after one day, and indicates that calibration should be performed every day. Yes.

  In S205, a message for prompting calibration shown in FIG. 5 is displayed via the UI (104).

  FIG. 3 shows the calibration process of the present embodiment, which is started when the user instructs the selection and execution of calibration by the print system via the UI (104), for example.

  In S301, the calibration patch is output by the printer (102).

  FIG. 6 is a diagram schematically showing this calibration patch. As shown in the figure, the patch pattern of the calibration patch is printed with one patch for each of the gradation values (C0 to C15, M0 to M15, Y0 to Y15, K0 to K15) of 0 to 15 for each color. Is done.

  In S302, the calibration patch output in S301 is measured using the densitometer (103).

  In S303, calibration data is calculated based on the measured density value of each patch. That is, a plurality of measured density data corresponding to each gradation value is used as measured density data for each gradation value, and the contents of calibration data are updated based on this. The calculation of the calibration data can be executed by a known method, and detailed description thereof is omitted here.

  In S304, the calibration data calculated in S303 is recorded in the storage device (107).

  In S305, the setting value indicating whether or not the relational expression recorded in the storage device (107) is updated via the UI (104) is referred to. If the setting is to be updated, the process proceeds to S306 and the update is performed. If the setting is not made, the calibration process is terminated.

  In S306, the elapsed time is calculated from the previous calibration date and time acquired from the storage device (107) and the current date and time acquired from the RTC (108).

  In S307, the fluctuation amount is calculated from the colorimetric values of each patch measured in S302, and the elapsed time and the measured value are recorded in the storage device (107).

  In this embodiment, the average value of the difference between the previous measurement value and the current measurement value in each patch is used as the fluctuation amount, and the following calculation formula is used.

また、本実施例ではインク色毎の濃度値の平均値を用いたが、その代わりに測色計を用いてCIE L^*a^*b^*を測定し、ΔEを精度の指標として使用することも可能である。

In this embodiment, the average value of the density values for each ink color is used. Instead, CIE L ^* a ^* b ^* is measured using a colorimeter, and ΔE may be used as an accuracy index. Is possible.

  In S308, the lookup table is regenerated from the variation calculated in S307 and the measured values recorded in the storage device (107) so far, recorded in the storage device (107), and the process ends.

  In the present embodiment, the recalculation formula uses the following formula, rounding the elapsed time in days.

本実施例ではこのような計算式を使用しているが、多項式近似などのデータの近似値を求める計算式を用いることも可能である。

In this embodiment, such a calculation formula is used, but a calculation formula for obtaining an approximate value of data such as polynomial approximation can also be used.

1 is a block diagram illustrating a configuration of a print system in an embodiment according to the present invention. It is a flowchart which shows the process of the calibration space | interval check in the Example. It is a flowchart which shows the process of the calibration in the Example. It is a setting screen of the calibration in the same Example. It is a setting screen of the calibration in the same Example. It is a screen which prompts the calibration in the same Example. It is a calibration patch in the same Example.

Explanation of symbols

101 PC
102 Printer
103 Densitometer
104 UI
105 CPU
106 working memory
107 Storage device
108 RTC

Claims (13)

  A printing system that performs output based on output data, measures a patch image output from a target output device, and calibrates the color reproducibility of the output device based on the correspondence between the measured value and the output signal Means for recording the measured value when the previous color calibration was performed by the output device, means for recording the date and time when the previous color calibration was performed, and the recorded previous measured value. A means for calculating a fluctuation amount of the output characteristic, calculating a relationship between the fluctuation amount and the elapsed time from the calculated fluctuation amount and an elapsed time from the previous color calibration, and cumulatively updating the relationship; A printing system characterized by recording.   3. The method according to claim 1, wherein when a time determined to exceed a predetermined allowable variation amount from a relationship between the recorded variation amount and the elapsed time has elapsed, notification that color calibration needs to be executed is provided. And a printing system.   2. The print according to claim 1, wherein execution of color calibration is limited when a time determined to exceed a predetermined allowable fluctuation amount from a relationship between the recorded fluctuation amount and elapsed time has not elapsed. system.   2. The printing system according to claim 1, wherein color calibration is automatically executed when a time determined to exceed a predetermined allowable fluctuation amount from the relationship between the recorded fluctuation amount and the elapsed time has elapsed. .   5. The print system according to claim 2, 3, or 4, wherein an allowable variation is recorded for each output device.   2. The printing system according to claim 1, wherein the relationship between the fluctuation amount and the elapsed time is recorded for each output device.   2. The printing system according to claim 1, wherein whether or not to update the relationship between the fluctuation amount and the elapsed time can be explicitly specified.   2. The printing system according to claim 1, wherein the relationship between the fluctuation amount and the elapsed time is a function having the elapsed time as an input value.   2. The printing system according to claim 1, wherein the relationship between the fluctuation amount and the elapsed time is a lookup table using the elapsed time as an input value.   2. The printing system according to claim 1, wherein the relationship between the fluctuation amount and the elapsed time is recorded in a recording area provided in the output device.   In claim 1, the relationship between the fluctuation amount and the elapsed time is determined by using a general-purpose recording medium (for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, non-volatile). A printing system characterized by recording on a memory card.   The printing system according to claim 1, wherein a measurement value at the time of previous color calibration is recorded in a recording area provided in the output device.   In claim 1, the measured value at the time of previous color calibration is a general-purpose recording medium (for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, A printing system characterized by recording on a non-volatile memory card.

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