JP2006021401A - Image output device with calibration function - Google Patents

Abstract

In an image output device such as a color printer, a test chart and a reference chart are visually evaluated so that an output image does not differ due to a change in state of an internal mechanism over time, based on the evaluation result. Perform calibration.
An image output device includes a calibration execution determination unit, a calibration function unit, and an image output device unit. The image output device 1 performs normal printing and outputs a test chart for calibration (for example, a laser beam printer), and fluctuations in evaluation items such as graininess, gradation, and color reproducibility. There are few image output means (eg, ink jet printer) that outputs a reference chart for calibration. Using the test chart and the reference chart, visual evaluation is performed on predetermined evaluation items, and the evaluation result is input to the image output device. To determine whether to perform calibration.
[Selection] Figure 1

Description

  The present invention relates to an image output apparatus with a calibration function, and more particularly to an image output apparatus with a calibration function that performs evaluation using a test chart and a reference chart and performs calibration based on the evaluation result.

Conventionally, an image output apparatus such as a color printer may have different output images even if the same image is output due to a change in the state of the internal mechanism of the apparatus over time. In order to solve this problem, it is necessary to periodically calibrate the image output apparatus. This calibration is read when the image output device is equipped with a reading device such as a scanner, as in “Image processing device and method and image forming device” disclosed in Patent Document 1, for example. A method has been proposed in which visual characteristics are added to an image signal and image quality is determined based on the image signal.
However, the method disclosed in Patent Document 1 has a problem that the image forming apparatus needs to be equipped with a reading device such as a scanner in order to determine the image quality, and the image forming apparatus becomes large.

Therefore, in the “color printer calibration adjustment method” disclosed in Patent Document 2, for each of CMYK highlight, middle, and shadow, a test chart printed out is compared with a reference chart prepared in advance. Proposals have been made to perform calibration by selecting patches of the same density.
However, in the method disclosed in Patent Document 2, it is necessary to request the user to store and manage the reference chart, and the reference chart fading at the time of storage is a problem.

In “Color Laser Printer Calibration Method and Test Chart” disclosed in Patent Document 3, a standard solid patch and an evaluation target patch are output on the test chart, and a patch with the smallest color difference is selected. Therefore, what performs calibration has been proposed.
However, the method disclosed in Patent Document 3 has a problem in that a stable reference patch cannot be output because the reference patch is also output from the same output device as the test patch.
JP 2000-168054 A Japanese Patent Laid-Open No. 10-6562 JP 2002-44455 A

The present invention has been made for the purpose of solving the above-mentioned problems of the prior art. The test chart is output from the first output device, and the reference chart is evaluated in the evaluation items rather than the first output device. Output from the second output device (reference chart output device) with little fluctuation, and by performing a visual comparison between the test chart and the reference chart, the image quality evaluation item is evaluated, and the calibration is performed based on the evaluation result. An image output apparatus with a calibration function is provided. Here, the second output device may be incorporated in the first output device, or may be connected to the first output device via a network.
It is another object of the present invention to provide an image output device with a calibration function that can easily obtain a reference chart and accurately evaluate the image quality of a test chart output from a first output device using the reference chart. And
It is another object of the present invention to provide an image output apparatus with a calibration function that eliminates the need to store and manage a reference chart for image quality evaluation by a user and eliminates the influence of fading.

  The invention according to claim 1 uses the first image output means for outputting a test chart, the second image output means for outputting a reference chart, the test chart and the reference chart, and performs evaluation on a predetermined evaluation item. And an image output device with a calibration function having means for performing calibration based on the evaluation result.

  According to a second aspect of the present invention, in the image output device with a calibration function according to the first aspect, the second image output means is an image output means with less variation in the evaluation items than the first image output means. It is characterized by being.

  According to a third aspect of the present invention, in the image output device with a calibration function according to the first or second aspect, the second image output means is incorporated in the first image output means. To do.

  According to a fourth aspect of the present invention, in the image output apparatus with a calibration function according to the second or third aspect, the second image output means is an ink jet printer.

  According to a fifth aspect of the present invention, in the image output device with a calibration function according to any one of the first to fourth aspects, the evaluation item is at least one of graininess, gradation, and color reproducibility. Features.

  According to a sixth aspect of the present invention, in the image output device with a calibration function according to any one of the first to fifth aspects, the patch group in which patches of predetermined patterns having different brightness are arranged is output as a test chart. One image output means, the second image output means for outputting, as a reference chart, a pattern composed of patch groups having substantially the same brightness as each patch of the test chart and having different variations, and the test chart As a result of the comparison of the granularity between the reference chart and the reference chart, a selecting means for selecting a patch that is closest to the patch of the test chart from the reference chart, and a granularity deterioration level based on the patch selected by the selecting means Determining means for determining whether to perform calibration based on the granularity deterioration level determined It is characterized in.

  According to a seventh aspect of the present invention, in the image output device with a calibration function according to any one of the first to fifth aspects, a patch group in which a plurality of density regions arranged with a constant density difference are arranged is output as a test chart. The first image output means, the second image output means for outputting, as a reference chart, a pattern in which a density area has a predetermined reference density, and a result of density comparison between the test chart and the reference chart, It has a selection means for selecting a patch most similar to the patch of the test chart from the reference chart, and a calculation means for calculating density correction data based on the patch selected by the selection means.

  According to an eighth aspect of the present invention, there is provided a first image output means for outputting, as a first test chart, a patch group in which a plurality of density areas are arranged in color materials of cyan, magenta, yellow, and black, and a density area. The second image output means for outputting a pattern having a predetermined reference density as a first reference chart, and the result of comparing the density between the test chart and the reference chart is that the patch of the first test chart is the most. A first selection unit that selects an approximate patch from the first reference chart, a unit that performs density adjustment based on the patch selected by the first selection unit, and a ratio of cyan, magenta, and yellow is slightly increased. A third image output means for outputting, in a plurality of density areas, a patch group in which the natural images changed one by one are arranged as a second test chart, and the density area from a predetermined reference color The fourth image output means for outputting the pattern to be used as the second reference chart, and the result of the comparison in the hue between the second test chart and the second reference chart is An image with a calibration function having second selection means for selecting an approximate patch from the second reference chart and calculation means for calculating color density correction data based on the patch selected by the second selection means. It is an output device.

Effect on Claim 1 In the image output apparatus according to claim 1, since the reference chart is output from the image output means at the time of calibration, it is not necessary to store and manage the reference chart by the user, and the influence of fading Can be eliminated.

Effect on Claim 2 In the image output device according to claim 2, since the second image output means for outputting the reference chart has little fluctuation in the evaluation items, a reference chart that hardly fluctuates with time is output. can do.

Advantageous Effects on Claim 3 In the image output apparatus according to claim 3, since the second image output means is incorporated in the first image output means, the reference chart can be output in a simple form. it can.

Advantageous Effects on Claim 4 In the image output system according to claim 4, since the second image output means is an ink jet printer, a reference chart with less fluctuation can be output with a simpler configuration.

Effect on Claim 5 In the image output system according to claim 5, since the evaluation items are graininess, gradation, and color reproducibility, the image quality can be evaluated linearly.

The image output system according to claim 6 has a test chart comprising a patch group in which patches of patterns having different brightness are arranged, and each patch of the test chart has substantially the same brightness, and Since a reference chart comprising patterns of patch groups having different variations is used, the granularity deterioration level can be easily and accurately known, and it can be accurately determined whether or not to perform calibration.

Effect on Claim 7 In the image output system according to claim 7, the test chart including a patch group in which a plurality of density regions arranged with a constant density difference are arranged, and the density region is based on a pattern having a predetermined reference density. Therefore, calibration of gradation characteristics can be performed with high accuracy.

The image output system according to claim 8, wherein the first test chart comprising a patch group in which a plurality of density areas are arranged in a CMYK color material and a pattern having a predetermined reference density in the density area. A first test chart composed of patches, a second test chart composed of a patch group in which natural images in which CMY ratios are changed little by little are arranged, and a pattern of a predetermined reference color in a density region is a second reference chart. Therefore, calibration of color reproducibility can be performed with high accuracy.

In an image output device such as a color printer, a test chart and a reference chart are output from the image output device, the test chart is visually evaluated using the reference chart, and whether or not calibration is performed based on the evaluation result is accurately determined. The output image is not changed over time due to a change in state of the internal mechanism of the image output device over time, and the image output device for that purpose is used during normal printing and calibrated. The first image output means (for example, a laser beam printer) used for outputting a test chart at the time of calibration and the evaluation items such as graininess, gradation, and color reproducibility are small, and at the time of calibration Second image output means (for example, an inkjet printer) comprising an inkjet printer that outputs a reference chart. Using the test chart and the reference chart, visual evaluation is performed on predetermined evaluation items, and based on the evaluation result, the image output device determines whether or not to perform calibration, and calibration is performed. When performing, it has means for performing calibration by changing or updating data such as an output γ correction table of the image output apparatus. Thus, the reference chart can be easily obtained, and the reference chart can be used to accurately evaluate the image quality of the test chart output from the first output device, and the reference chart for performing the image quality evaluation can be obtained by the user. This eliminates the need for storage and management, and eliminates the effects of fading.
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.

The image output apparatus 1 according to the first embodiment of the present invention uses a color laser beam printer (hereinafter also referred to as “LBP”) as a printing apparatus and normally performs electrophotographic printing, but has a calibration function. And an auxiliary print head of an ink jet printer used for calibration.
FIG. 1 is a block diagram illustrating a functional configuration of an image output apparatus 1 including a color laser beam printer according to a first embodiment. The image output apparatus 1 includes a calibration execution determination unit 11, a calibration function unit 12, and an image output device. Part 13.

FIG. 5 is a block diagram illustrating a configuration of a color laser beam printer used as the image output apparatus according to the first embodiment.
A color laser beam printer (LBP) 1030 is a component of the image output apparatus 1 together with a print head of an inkjet printer (not shown), and is connected to a host computer 1001 as an information processing apparatus such as a personal computer via a communication line 1002. Configure the printing system. In the LBP 1030, the printer controller 1031 is a control unit that executes operation control and data processing of the entire printer. That is, the printer controller 1031 interprets and prints control codes and data in the control by the CPU 1033 and the program ROM 1034 for storing the processing procedure of the control performed by the CPU 1033 and the CPU 1033 for controlling the data processing in the entire control unit. The RAM 1035 used as a work area for processing necessary for printing, processing of print data, and the like can be used to execute the above-described operation control and data processing.

  In the program ROM 1034, as shown in FIG. 5, based on print data from the host computer 1001, image information generation 1041, which is a processing program for performing image processing and generating an image object to be printed by the printer, this image information generation Execution / determination 1044 which is a processing program for executing calibration for updating predetermined table data in the processing of 1041, control of single-sided printing or double-sided printing of printing, and a paper feed port and paper discharge specified by the user A paper supply / discharge port setting 1042 which is a processing program for setting a port is also stored.

  With the above configuration, the printer controller 1031 executes print processing based on print data sent from the host computer 1001. At this time, the input / output buffer 1032 controls input / output of data to / from the host computer 1001. Data that is input / output via the host I / F unit 1048 is temporarily stored. Further, the bitmap image transfer unit 1040 develops the image object generated by the image processing generation 1041 into a bitmap image, and transfers it to the print engine unit 1036 via the engine I / F unit 1046.

  In addition to the above configuration, the LBP 1030 or its printer controller 1031 has an operation panel 1037 for a user to perform various operations related to the printer, and a panel I / F unit 1047 for signal connection between the operation panel and the printer controller 1031. Also, an external memory 1038 such as a flexible disk, which is used for storing print data and various information of the printer, and a memory I / F unit 1039 for data connection between the external memory 1038 and the printer controller 1031, Further, a system bus 1043 for connecting the above-described elements is provided.

2 is a block diagram illustrating a functional configuration of the calibration execution determination unit 11, FIG. 3 is a block diagram illustrating a functional configuration of the calibration function unit 12, and FIG. 4 is a block illustrating a functional configuration of the image output device unit 13. FIG.
The calibration execution determination unit 11 includes an input information recognition unit 111, a test chart output processing unit 112, a deterioration level recognition unit 113, a deterioration level storage unit 114, an execution determination unit 115, a usage information counting unit 116, and an execution reference information storage unit 117. And an output processing unit 118.
The calibration function unit 12 includes a test chart output processing unit 121, a pattern table storage unit 122, a pattern information recognition unit 123, and a pattern setting unit 124, and the image output device unit 13 includes a reference chart output processing unit 131. Become.

The input information recognition unit 111 recognizes that the calibration button has been selected on the operation screen of the image output apparatus 1 when the user wants to perform calibration.
Here, the image output device unit 13 corresponds to a printing device incorporated in the image output device 1, that is, the LBP of the first embodiment, and has a predetermined evaluation item (for example, graininess and gradation) than the image output device 1. It is assumed that an output device (an ink jet printer in the case of Example 1) with little variation in color reproducibility is used, and calibration is periodically performed at a predetermined time.

For example, the printing apparatus incorporated in the image output apparatus 1 is configured such that a print head portion of an ink jet printer is attached to a paper discharge port of an LBP.
An inkjet printer basically has a simpler process up to printing than an electrophotographic printer (LBP) or the like, and therefore there are few variations in evaluation items. Further, the normal calibration is performed at a constant cycle or a constant condition according to the elapsed time from the start of printing and the number of printed sheets. That is, it is determined whether or not such a cycle or condition is satisfied immediately before executing printing (for example, after receiving print data) or during execution of printing. Calibration is executed.

  In the case of the above-described LBP, the calibration is performed when the density of the patch image formed with toner on the photosensitive drum or the intermediate transfer member is read by an optical sensor, and image data is processed based on this. Data such as an output γ correction table to be used is changed or updated.

When the input information recognition unit 111 recognizes that the user has selected the calibration button on the operation screen of the image output apparatus 1, the reference chart output processing unit 131 uses the calibration chart recorded in advance on the hard disk or the like. The reference chart is printed based on the chart data.
When the input information recognition unit 111 recognizes a command for outputting a test chart, the test chart output processing unit 112 prints the test chart using calibration chart data recorded in advance on a hard disk or the like.
FIG. 6 is a diagram illustrating a test chart for evaluating the granularity deterioration level (roughness of the image), and FIG. 7 is a diagram illustrating a reference chart for evaluating the granularity deterioration level.
In this embodiment, it is assumed that the smaller the number of levels, the lower the granularity (higher image quality), and the higher the number of levels, the higher the granularity (bad image quality).

  Then, the reference chart and the test chart are visually compared. The deterioration level recognition unit 113 recognizes the visual result input on the operation screen of the image output apparatus 1 and stores it in the deterioration level storage unit 114. The usage information counting unit 116 counts (increments) or measures usage information such as the number of used sheets, operating time, and various state information (for example, toner density control voltage value) by using an image output device made of LBP. Is.

  A sensor for measuring the number of sheets used, a sensor for measuring operating time, various state information, and the like are provided in the engine unit 1036. Usage information detected by the sensor is temporarily stored in the RAM 1035.

  In addition, a criterion value for determining whether to perform calibration is stored in advance in the criterion information storage unit 117. The information stored in the visual result and usage information counting unit 116 is compared with the reference value stored in the execution reference information storage unit 117, and the execution determination unit 115 determines whether or not to perform calibration. . The execution determination unit 115 determines that the calibration is not performed when the level is 6 or higher (levels 6 and 7 are targeted). The level will be described later in the description of the reference chart.

  When it is determined that the calibration is not performed, the usage information (the number of used sheets, the operating time, etc.) from the previous calibration is acquired, and it is determined whether or not the calibration is performed including the usage information. In this case, the execution determination unit 115 determines that the calibration is not performed when the granularity deterioration level is 5 and the number of printed sheets is less than 10,000 sheets, and the granularity deterioration level is 6 and the granularity deterioration level is 6 or more. If there is, it is determined that calibration is to be performed. Thereby, it is possible to accurately determine whether or not to perform calibration.

  When it is determined that the calibration is to be performed, the calibration is performed by the calibration function unit 12 illustrated in FIG. The calibration function unit 12 includes a test chart output processing unit 121, a pattern table storage unit 122, a pattern information recognition unit 123, and a pattern setting unit 124.

  The test chart output processing unit 121 prints several types of processing patterns using a halftone processing pattern table (several types of processing patterns) stored in advance in the pattern table storage unit 122 as a test chart as shown in FIG. To do. The processing pattern desired by the user is visually selected by the test chart and is input on the operation screen of the image output apparatus 1. The pattern information recognition unit 123 recognizes the processing pattern selection result input on the operation screen of the image output apparatus 1, and the pattern setting unit 124 sets the processing pattern.

FIG. 8 is a diagram showing an operation screen displayed when a user selects a processing pattern desired by the user and inputs the processing pattern on the operation screen, and FIG. 9 shows a partial display screen on the operation screen shown in FIG. FIG.
An example of an input method on the operation screen when the user visually selects a desired processing pattern and inputs it to the operation screen 2000 is as follows. When a calibration execution button displayed on the operation screen 2000 is pressed, the display screen 2001 is displayed. The display is changed to a display as shown in FIG. Then, a pattern is selected using the up and down buttons 2003 on the operation screen. Clicking the up button increases the number, and clicking the down button decreases the number. For example, if the initial setting is displayed as 1 and it is determined that it is 6 by visual observation, 6 is displayed by clicking the up button five times. Then click the setting button.

When it is determined that the calibration is not performed, the output processing unit 118 can display or print on the operation screen that the calibration is not performed for the user. Accordingly, the user can know that the image quality does not improve even if the image output apparatus 1 performs the calibration, and the user support is improved.
As means for notifying the user that the calibration is not performed, for example, the button without calibration on the operation screen shown in FIG. 8 is blinked.

Calibration performed by the image output apparatus according to the first embodiment will be described.
FIG. 10 is a flowchart when the image output apparatus according to the first embodiment performs calibration.
First, when a user who is a user selects a calibration button on the operation screen 2000 of the image output apparatus 1 for a calibration request, the test chart output processing unit 112 causes a granularity deterioration level ( A test chart 1120 as shown in FIG. 6 for evaluating the degree of roughness of the image is output (step 101). On this test chart, a single-color patch group with varying brightness (for example, five levels from a (bright) to e (dark)) is output. Here, the single color is a memory color such as black or skin color.

  Further, a reference chart as shown in FIG. 7 is output from the reference chart output processing unit 131 (step 102). The reference chart patch describes a granularity deterioration level (for example, deterioration level 1 (good image quality) to 7 (poor image quality)). It is assumed that the smaller the number of levels, the lower the granularity (good image quality), and the higher the number of levels, the higher the granularity (bad image quality). On this reference chart, there is formed a single color patch created with data obtained by adding Gaussian noise to electronic data having the same brightness as that of the test chart and having no noise. By outputting the reference chart from the image output apparatus 1, it is not necessary to save and manage the reference chart by the user, and the influence of fading can be eliminated.

  Here, as described above, the image output device unit 13 uses an image output device (for example, an ink jet printer) that has less variation in the predetermined evaluation items (granularity in this example) than the image output device 1. As a result, a reference chart with little variation such as fading can be output in a simple form.

  Next, the user selects a patch having the same brightness as that of the reference chart from the patches on the test chart (for example, c), and visually checks the patch having the closest graininess (roughness) to the patch on the test chart. (For example, 6) (step 103). As a result, the image quality level can be obtained in a simple form without using a scanner or the like. Then, the numerical value written beside the selected patch is registered in the image output apparatus 1 (step 104).

Here, a method for registering the image quality level will be described.
When the calibration execution button displayed on the operation screen 2000 shown in FIG. 8 is pressed, the display screen 2001 is switched to the display shown in FIG. 9 and the operation moves to pattern selection. Then, a pattern is selected using the up and down buttons 2003 on the operation screen. When the upward button is clicked, the number displayed on the display screen 2001 increases, and when the downward button is clicked, the number decreases. For example, if the initial setting is displayed as 1 and it is determined that it is 6 by visual observation, 6 is displayed by clicking the up button five times. Then click the setting button.

  Next, it is determined whether or not to perform calibration based on the registration result (step 105). Whether or not to perform calibration is determined based on a predetermined value R1 set in advance in the execution determination unit 115.

  Next, it is determined whether or not the calibration is to be performed based on the registration result and the usage information (the number of used sheets and the operating time) from the previous calibration execution time. This is because the higher the granularity level (the poorer the image quality), the less the improvement in image quality is desired even if calibration is performed. This is because it is difficult to improve the image quality by performing calibration. Therefore, to determine whether or not to perform calibration, it is necessary to consider both the granularity level and the usage information from the previous replacement time.

  First, when the granularity level is very high (image quality is poor), improvement in image quality is not desired even if calibration is performed, regardless of the usage information from the previous calibration execution time. Therefore, a granularity level that does not improve image quality even when calibration is performed to the predetermined value R1 is set. For example, when the granularity level is 6 or more, it is assumed that no improvement in image quality is desired even if calibration is performed. In this case, level 6 is set as the predetermined value R1.

Next, a case other than the level set as described above (granularity level that does not improve image quality even when calibration is performed) will be described.
FIG. 11 is a diagram illustrating a relationship between the granularity level and the reference value of the number of used sheets from the previous calibration execution time when performing calibration.
As shown in FIG. 11, the execution standard information storage unit 117 stores in advance a value based on the number of used sheets from the previous calibration execution time for each granularity level, which is greater than the set number of used sheets. In this case, it is determined that the calibration is not performed. Of course, not only the number of used sheets from the previous replacement time but also the setting using the operating time and the number of used sheets may be used.

Therefore, first, the execution determination unit 115 determines that the calibration is not performed when the level is 6 or higher (levels 6 and 7 are the targets of calibration) (step 109).
Next, when it is not determined that the calibration is not performed, the usage information (the number of used sheets, the operating time, etc.) from the previous calibration execution time is acquired (step 106), and the calibration including the usage information is performed. It is determined whether or not to implement (step 107). In this case, the execution determination unit 115 determines that the calibration is not performed when the granularity deterioration level is 5 and 10,000 or more sheets (step 109), and the granularity deterioration level is 5 and less than 10,000 sheets. If so, it is determined that calibration is to be performed (step 108). Thereby, it is possible to accurately determine whether or not to perform calibration.

  If it is determined that calibration is not to be performed (step 109), the user is notified of information for prompting maintenance work by displaying the information on the image output apparatus. Here, as means for prompting the maintenance work, for example, the maintenance work button on the operation panel 2000 shown in FIG.

  Information that prompts maintenance work is transmitted to a central management device such as the host computer 1001 that remotely manages the image output apparatus 1 via the host I / F unit 1048 that controls data input / output with the host computer 1001. To do. As a result, the user can know the state of the image output apparatus, and the user support can be improved.

  Conversely, if it is determined that calibration is to be performed (step 108), calibration is performed by a predetermined method. As an example of the calibration method, first, different halftone processing (for example, dither processing, error diffusion processing) patterns are output as a test chart. Here, halftone processing such as dither processing and error diffusion processing is known, and an example thereof is described in Japanese Patent Application Laid-Open No. 2003-69820 “Image Information Processing Device”.

  There are test charts for evaluating graininess and test charts for evaluating sharpness. Depending on the processing pattern, sharpness may be deteriorated if the granularity is emphasized. On the other hand, if the emphasis is on sharpness, the graininess may deteriorate. Therefore, a processing pattern (for example, 3) that takes into account the correlation between graininess and sharpness is selected and input to the image output apparatus. A processing pattern is set according to the input information. Thereby, the image quality desired by the user can be provided with high accuracy.

The image output apparatus according to the second embodiment of the present invention has a calibration function in the image output apparatus.
12 and 14 are block diagrams showing a part of the functional configuration of the first and second image output apparatuses, respectively.
The first and second image output devices 2 and 3 include calibration units 21 and 31, respectively. The second image output device 3 is connected to the first image output device 2 via a network, and is an image output device with less variation in predetermined evaluation items than the first image output device 2. Here, the second image output device 3 is selected. When there are a plurality of image output devices connected to the first image output device 2 via the network, the second image output device 3 is selected. 3 is selected from the plurality of image output devices based on usage information (number of used sheets, operating time, etc.) from the previous calibration execution time (for example, the number of used sheets from the previous calibration execution time is small), etc. Of course, this method is not limited to this method.

FIGS. 13 and 15 are block diagrams showing the configurations of the first and second calibration function units 21 and 31, respectively.
In FIG. 13, the first calibration function unit 21 includes an input information recognition unit 211, a test chart output processing unit 212, a density step difference information recognition unit 213, a correction data calculation unit 214, and a correction data table storage unit 215. In FIG. 15, the second calibration function unit 31 includes an input information recognition unit 311 and a reference chart output processing unit 312.
When the user wants to perform calibration, a calibration execution button is selected on the operation screen of the first image output apparatus 2. Information on selection of the calibration button is recognized by the input information recognition units 211 and 311. The operation screen 2000 shown in FIG. 8 is also used as the operation screen of the image output apparatus according to the second embodiment. When the calibration execution button is selected, the display screen 2001 is switched to the pattern selection screen, and the up / down button 2003 is clicked. The pattern can be selected.

FIG. 16 is a diagram illustrating a test chart for evaluating the gradation property output from the image output apparatus according to the second embodiment. FIG. 17 is a diagram for evaluating the gradation property output from the image output apparatus according to the second embodiment. It is a figure which shows a reference | standard chart.
When the input information recognition unit 211 recognizes that the calibration is to be performed, the test chart output processing unit 212 prints the test chart using the calibration chart data recorded in advance on the hard disk or the like.
When the input information recognition unit 311 recognizes that the reference chart output unit 311 outputs the reference chart, the reference chart output processing unit 312 prints the reference chart with the calibration chart data recorded in advance on the hard disk or the like. Note that the calibration chart data recorded in the second image output device 2 can be acquired via the network without recording the calibration chart data in the third image output device 3.

  The user visually compares the test chart and the reference chart, and inputs the density step difference on the operation screen of the first image output apparatus 2. The density step difference information recognition unit 213 recognizes the density step difference input on the operation screen of the first image output apparatus 2, calculates correction data in the correction data calculation unit 214, creates a correction data table, The data is stored in the correction data table storage unit 215.

Calibration performed by the image output apparatus according to the second embodiment will be described.
FIG. 20 is a flowchart when the image output apparatus according to the second embodiment performs calibration.
First, when a user who is a user selects a calibration button on the operation screen of the image output apparatus for a calibration request, the first image output apparatus 2 evaluates the gradation shown in FIG. The test chart is output (step 201).

  On the test chart, black (K), cyan (C), magenta (M), and yellow (Y) are arranged with a constant density difference (5%) from 0% to 100%. 21 color patches are output. These color patches are divided into three density groups in the descending order of density: “highlight” (70% to 100%), “middle” (35% to 65%), and “shadow” (0% to 30%). Has been.

  Next, the second image output device 3 outputs a reference chart for evaluating the gradation shown in FIG. 17 (step 202). Since the second image output device 3 is an image output device with less variation in predetermined evaluation items (eg, gradation) than the first image output device 2, the reference chart can be less varied. Further, by outputting the reference chart from the second image output device, it is not necessary to save and manage the reference chart by the user, and the influence of fading can be eliminated.

On the reference chart, long color patches corresponding to the lengths of the seven color patches on the test chart are “highlight”, “middle”, and “shadow” for each of K, C, M, and Y. Three density groups are output. Here, the halftone density of the long color patch of “highlight”, “middle”, and “shadow” is the middle halftone density of the seven color patches of each density group, and is 85%, 50%, 15 respectively. %. The color patches are arranged side by side in K, C, M, and Y, but may of course be arranged in one vertical column.
Note that the test chart data is not corrected by the correction data.

Next, a visual comparison between the reference chart and the test chart is performed (step 203).
FIG. 18 is a diagram showing a test chart when visual comparison is performed, and FIG. 19 is a diagram showing a reference chart when visual comparison is performed.
The visual comparison is performed, for example, as shown in FIGS. 18 and 19, and a plurality of density regions (seven color patches) of the test chart in each density group (highlight, middle, shadow), and these color patches. Two locations with the long color patch of the reference chart belonging to the same density group are compared. In this comparison, the density of the long color patch is searched for which density among the seven color patches of the test chart, and the number of patches shifted (density level difference) is found. For example, when the density of a long color patch matches the intermediate color patch density of seven color patches, the density step difference is zero, and when the density matches the highest color patch density If the density step difference is +3 steps, the density step difference is -3 steps when the density of the color patch matches the lowest density. Then, for each of Y, M, C, and K, density step differences (correction data) at a total of 12 points of highlight, middle, and shadow portions are obtained.

  Next, the user inputs the correction data on the operation screen of the first image output device 2 (step 204). Based on the input, it is determined whether or not calibration is necessary (step 205). When there is no need for calibration, that is, when the density difference in each of the highlight, middle, and shadow portions in each of Y, M, C, and K is all zero, or a request such as “cancel” If there is, calibration adjustment ends (step 206).

  When calibration is necessary, the printer condition correction data is calculated based on the inputted density step differences in highlight, middle, and shadow portions at Y, M, C, and K, and a correction data table is created (step 207).

Here, the calculation method will be described.
If the QL value of the signal to be actually input to the output unit that outputs data is Q ′, the equation for the calculation is Equation 1.
Q ′ = Q + (α * ΔQ) ..Equation 1
Where α is the density step difference input on the operation screen of the image output apparatus, ΔQ is the amount of variation in the QL value for each patch density difference by one step, and Q is the reference QL value.
Then, Qh values serving as references in the highlight, middle, and shadow portions are set as Qh, Qm, and Qs, respectively, and Qh ′, Qm ′, and Qs ′, which are respective Q ′ values, are obtained using Equation 1, and Q and Q When the relationship with Q ′ is plotted on a graph, it is represented as points h, m, and s in FIG.
FIG. 21 is a graph showing a relationship between a reference QL value: Q and a QL value of a signal to be actually input: Q ′.

  As shown in FIG. 21, in the relationship between Q and Q ′, when there is no density step difference between the reference chart and the test chart, the three points h, m, and s are on a straight line (Q ′ = Q). Although there is a density step difference, it can be seen that there is a difference between αh * ΔQh, αm * ΔQm, and αs * ΔQs. Here, αh, αm, and αs represent density step differences in the highlight, middle, and shadow portions, and ΔQh, ΔQm, and ΔQs represent ΔQ values in the highlight, middle, and shadow portions.

  Then, a conversion curve passing through the three points h, m, and s is approximately obtained, and intermediate points other than the three points are interpolated with the conversion curve. This conversion curve is obtained by approximating with an arc passing through the three points or a quadratic function. Based on the conversion by the conversion curve, a correction data table is created for each color of Y, M, C, and K.

  When the correction data table is created as described above, the correction data table is registered in the correction data table storage unit 215 (step 208). As a result, calibration in gradation can be accurately performed in a simple form.

  The correction data calculation method outputs a test chart that is not corrected with the correction data, and calculates the correction data from the density step difference determined from the test chart. However, the correction data is limited to this example. is not. For example, a test chart corrected with appropriately selected correction data may be output, and the correction data may be corrected based on the density step difference determined from the corrected test chart.

The image output apparatus according to the third embodiment of the present invention has a calibration function in the image output apparatus.
22 and 24 are block diagrams showing part of the functional configuration of the first and second image output apparatuses, respectively.
The first and second image output devices 4 and 5 include calibration units 41 and 51, respectively. The second image output device 5 is connected to the first image output device 4 via a network, and is an image output device with less variation in predetermined evaluation items than the first image output device 4. Here, the second image output device 5 is selected. If there are a plurality of image output devices connected to the first image output device 4 via the network, the second image output device 5 Of course, there is a method of selecting a plurality of image output devices based on usage information (number of used sheets, operating time, etc.) from the previous replacement time (for example, a small number of used sheets from the previous replacement time). It is not limited to this method.

23 and 25 are diagrams showing the configurations of the first and second calibration function units 41 and 51, respectively.
23, the first calibration function unit 41 includes an input information recognition unit 411, a test chart output processing unit 412, a patch number recognition unit 413, a gamma curve creation unit 414, a natural image number unit 415, and a gamma curve correction unit 416. , A gamma table storage unit 417. In FIG. 25, the fifth calibration function unit 51 includes an input information recognition unit 511 and a reference chart output processing unit 512.

When the user wants to perform calibration, a calibration button is selected on the operation screen of the first image output device 4. Information on selection of the calibration button is recognized by the input information recognition units 411 and 511.
When the input information recognition unit 411 recognizes that the calibration button has been selected, the test chart output processing unit 412 outputs the first test chart based on the calibration chart data recorded in advance on a hard disk or the like. To do.
FIG. 26 is a diagram illustrating a first test chart output from the image output apparatus according to the third embodiment, and FIG. 27 is a diagram illustrating a first reference chart output from the image output apparatus according to the third embodiment.

  When the input information recognition unit 511 recognizes that the user has selected the calibration button, the reference chart output processing unit 512 generates the first reference chart based on the calibration chart data recorded in advance on the hard disk or the like. Output. Note that the calibration chart data recorded in the first image output device 4 can be acquired via the network without recording the calibration chart data in the second image output device 5.

The user visually compares the first test chart and the first reference chart, and inputs the patch numbers that are considered to have the same density on the operation screen of the first image output device 4. The patch number recognition unit 413 recognizes the patch number input on the operation screen of the first image output device 4, creates a gamma curve in the gamma curve creation unit 414, and generates a gamma curve creation result in the test chart output processing unit 412. A second test chart based on the above is output. When the input information recognition unit 511 recognizes that the patch number has been input, the reference chart output processing unit 512 displays the second reference chart based on the calibration chart data recorded in advance on the hard disk or the like. Output.
FIG. 28 is a diagram showing a second test chart, and FIG. 29 is a diagram showing a second reference chart.

  The user visually compares the second test chart and the second reference chart, and inputs a natural image number that seems to be correct in color and the like on the operation screen of the first image output device 4. The natural image number information recognition unit 415 recognizes the natural image number input on the operation screen of the first image output device 4, corrects the gamma curve in the gamma curve correction unit 416, and stores it in the gamma table storage unit 417. .

Calibration based on the configuration of the third embodiment will be described.
FIG. 30 is a flowchart when the image output apparatus according to the third embodiment performs calibration.
First, when a user who is a user selects a calibration button on the operation screen of the first image output device 4 for a calibration request, each of the first image output devices 4 as shown in FIG. A first test chart in which CMYK single color patches are formed at a certain reference density is output (step 301). Here, for each patch of the first test chart, the density is slightly changed up and down for each of C, M, Y, and K for output.

  Next, the second image output device 5 outputs a first reference chart in which C, M, Y, and K single color patches as shown in FIG. 27 are formed at a certain reference density. (Step 302). Since the second image output device 5 is an image output device with less variation in predetermined evaluation items (for example, color reproducibility) than the first image output device 4, it can output a reference chart with less variation. . Further, by outputting the reference chart from the image output apparatus, it is not necessary to save and manage the reference chart by the user, and the influence of fading can be eliminated.

  Then, using the first reference chart as a reference density, the first test chart is visually compared with the first test chart, and a patch that is considered to have the same density is selected (step 303). Then, the numbers of the selected patches C, M, Y, and K are registered on the operation screen of the image output device 4 (step 304). In this registration method, only the density characteristic of a certain point density is known, but here, the density characteristic of the other part is estimated from the density characteristic of that one point. Then, based on the estimated value, a gamma curve for each of C, M, Y, and K is created so as to have a prescribed density characteristic (step 305).

  Next, three types of second test charts (step 306) of highlight, middle, and shadow are respectively sent from the first image output device 4, and a second reference chart (step 307) is sent from the second image output device 5. ) Is output. Similarly to the above, the second image output device 5 is an image output device with less variation in predetermined evaluation items (for example, color reproducibility) than the first image output device 4, and therefore, a reference with less variation. A chart can be output. Further, by outputting the reference chart acquisition from the image output device, it is not necessary to save and manage the reference chart by the user, and the influence of fading can be eliminated.

  In this second test chart, a natural image is used for each density, and one of the C, M, and Y colors, for example, M density, is fixed on each second test chart. A plurality of natural images are output in such a way that the density of other colors is changed in the vertical and horizontal directions. Of course, M is fixed here, but C or Y may be fixed. In addition, an image having a ratio of colors that seems to be balanced among C, M, and Y in the gamma curve created based on the selection result of the single color patch is arranged at the center of each test chart. These second test charts are compared with the second reference chart by visual observation, natural images that are considered to be correct in color and the like are selected for each test chart (step 308), and the selection result is the first. Are registered on the operation screen of the image output apparatus 4 (step 309). Since the first image output device 4 knows the proportion of CMY that is balanced from the registration result, the correction of each gamma curve in a direction that improves the balance of C, M, and Y from the result. (Step 310). The correction of the gamma curve here is not a correction that perfectly matches the balance of C, M, and Y in the selection result of the natural image, but the result in C, M, and Y monochromatic colors is also taken into account. We will make corrections in a form that will not change and will be closer to the balance of the natural image selection results. The correction result of the gamma curve is stored in the gamma table storage unit 417 (step 311). Thereby, calibration in color reproducibility can be accurately performed in a simple form.

FIG. 3 is a block diagram illustrating a functional configuration of the image output apparatus according to the first embodiment. It is a block diagram which shows the function structure of a calibration implementation determination part. It is a block diagram which shows the function structure of a calibration function part. It is a block diagram which shows the function structure of an image output device part. It is a block diagram which shows the structure of a color laser beam printer. It is a figure which shows the test chart for evaluating a granularity degradation level (roughness degree of an image). It is a figure which shows the reference | standard chart for evaluating a granularity degradation level. It is a figure which shows the operation screen displayed when the user selects the process pattern which a user desires visually, and inputs it on an operation screen. It is a figure which shows a part of display screen on the operation screen shown in FIG. 6 is a flowchart when the image output apparatus according to the first embodiment performs calibration. It is a figure which shows the relationship between the granularity level at the time of performing calibration, and the reference value of the number of sheets used from the previous calibration execution time. 6 is a block diagram illustrating a part of a functional configuration of a first image output apparatus according to Embodiment 2. FIG. FIG. 10 is a block diagram illustrating a configuration of a first calibration function unit according to a second embodiment. 10 is a block diagram illustrating a part of a functional configuration of a second image output apparatus according to Embodiment 2. FIG. FIG. 10 is a block diagram illustrating a configuration of a second calibration function unit according to the second embodiment. It is a figure which shows the test chart for evaluating a gradation property. It is a figure which shows the reference | standard chart for evaluating a gradation property. It is a figure which shows the test chart at the time of performing a visual comparison. It is a figure which shows the reference | standard chart at the time of performing a visual comparison. It is a flowchart at the time of implementing a calibration. It is a graph which shows the relationship between QL value Q used as a standard, and QL value Q 'of the signal which should actually be inputted. 10 is a block diagram illustrating a part of a functional configuration of a first image output apparatus according to Embodiment 3. FIG. FIG. 10 is a block diagram illustrating a first calibration function unit according to a third embodiment. 10 is a block diagram illustrating a part of a functional configuration of a second image output apparatus according to Embodiment 3. FIG. FIG. 10 is a block diagram illustrating a second calibration function unit according to the third embodiment. It is a figure which shows a 1st test chart. It is a figure which shows a 1st reference | standard chart. It is a figure which shows a 2nd test chart. It is a figure which shows a 2nd reference | standard chart. It is a flowchart at the time of implementing a calibration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image output device, 11 ... Calibration execution determination part, 111 ... Input information recognition part, 112 ... Test chart output process part, 113 ... Deterioration level recognition part, 114 ... Deterioration level storage part, 115 ... Execution determination part, 116 ... usage information coefficient unit, 117 ... execution standard storage unit, 118 ... output processing unit, 12 ... calibration function determining unit, 121 ... test chart output processing unit, 122 ... pattern table storage unit, 123 ... pattern information storage unit, DESCRIPTION OF SYMBOLS 124 ... Pattern setting part, 13 ... Image output part, 131 ... Reference | standard chart output process part, 2 ... 1st image output apparatus, 21 ... Calibration function part, 211 ... Input information recognition part, 212 ... Test chart output process part 213 ... Density step difference information recognition unit, 214 ... Correction data calculation unit, 3 ... Second image output device, 31 ... Calibrate Functional unit, 311 ... input information recognition unit, 312 ... reference chart output processing unit, 4 ... first image output device, 41 ... calibration function unit, 411 ... input information recognition unit, 412 ... test chart output processing unit, 413 ... Patch number recognition unit, 414 ... Gamma curve creation unit, 415 ... Natural number recognition unit, 416 ... Gamma curve correction unit, 417 ... Gamma table storage unit, 5 ... Second image output device, 51 ... Second calibration Function unit, 511 ... input information recognition unit, 512 ... reference chart output processing unit, 1001 ... host computer, 1030 ... laser beam printer (LBP), 1031 ... printer controller, 2000 ... operation screen, 2001 ... display screen, 2003 ... Up and down button.

Claims (8)

  Using the first image output means for outputting a test chart, the second image output means for outputting a reference chart, the test chart and the reference chart, evaluation is performed on predetermined evaluation items, and calibration is performed based on the evaluation result. An image output apparatus with a calibration function, characterized by comprising means for performing   2. The image output apparatus with a calibration function according to claim 1, wherein the second image output means is an image output means with less variation in the evaluation items than the first image output means. Image output device with calibration function.   3. The image output device with a calibration function according to claim 1, wherein the second image output unit is incorporated in the first image output unit. apparatus.   4. The image output apparatus with a calibration function according to claim 2, wherein the second image output means is an ink jet printer.   5. The image output apparatus with a calibration function according to claim 1, wherein the evaluation item is at least one of graininess, gradation, and color reproducibility. Image output device. The image output device with a calibration function according to any one of claims 1 to 5,
The first image output means for outputting a patch group in which patches of predetermined patterns of different brightness are arranged as a test chart;
The second image output means for outputting, as a reference chart, a pattern consisting of a patch group having substantially the same brightness as each patch of the test chart and having different variations;
As a result of the comparison of graininess between the test chart and the reference chart, a selection unit that selects a patch that most closely matches the patch of the test chart from the reference chart;
Calibration means comprising: a granularity deterioration level determined based on the patch selected by the selection means; and a determination means for determining whether or not to perform calibration based on the granularity deterioration level. Image output device with functions. The image output device with a calibration function according to any one of claims 1 to 5,
The first image output means for outputting, as a test chart, a patch group in which a plurality of density regions arranged with a constant density difference are arranged;
The second image output means for outputting, as a reference chart, a pattern in which the density region has a predetermined reference density;
As a result of the comparison of the density between the test chart and the reference chart, a selection unit that selects a patch closest to the patch of the test chart from the reference chart;
An image output apparatus with a calibration function, characterized by having a calculation means for calculating density correction data based on the patch selected by the selection means. A first image output means for outputting, as a first test chart, a patch group in which a plurality of density regions are arranged in color materials of cyan, magenta, yellow, and black;
A second image output means for outputting, as a first reference chart, a pattern in which the density region has a predetermined reference density;
First selection means for selecting, from the first reference chart, a patch that is closest to the patch of the first test chart as a result of the comparison of the density between the first test chart and the first reference chart; ,
Means for adjusting the density based on the patch selected by the first selection means;
A third image output means for outputting, in a plurality of density regions, a patch group in which natural images in which the ratios of cyan, magenta and yellow are gradually changed are arranged as a second test chart;
A fourth image output means for outputting a pattern in which the density region is made of a predetermined reference color as a second reference chart;
Second selection means for selecting, from the second reference chart, a patch that most closely matches the patch of the second test chart as a result of comparison in hue between the second test chart and the second reference chart; ,
An image output apparatus with a calibration function, characterized by comprising calculation means for calculating color density correction data based on the patch selected by the second selection means.