JP2008022304A - Image forming apparatus and printer calibration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform high precision calibration (gradation correction) in which gradation characteristics can be matched to target values even during copy or print operation. <P>SOLUTION: A scanner correction data creator 91 creates scanner correction data based on image data of a reference document image formed by offset-printing or the like, and stores them in a scanner correction data storage 92. A gradation correction data creator 93 creates gradation correction data for copy imaging based on the image data of a test image read out by a scanner 77, creates gradation correction data for print imaging based on the image data obtained by correcting the test image data by the scanner correction data, and stores them in a gradation correction data storage section 94. A gradation correction processor 95 corrects the gradation of image data for copying based on the gradation correction data for copy imaging, and corrects the gradation of image data for printing based on the gradation correction data for print imaging. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a printer calibration apparatus.

  Conventionally, thermal recording systems, electrophotographic recording systems, ink jet systems, etc. have been used as recording systems for obtaining hard copies, such as copying machines and printers. In Japan, efforts are being made to improve image quality by taking advantage of their respective characteristics.

  In particular, the electrophotographic recording method uses electrostatic phenomenon of toner, which is a fine particle, so it is strongly affected by environmental changes and changes over time, and the image density varies slightly, or the image density varies depending on the machine used. There are differences. For this reason, in color image forming devices that require a more stable image density, the density of the test image formed on the paper is detected using image reading means such as a scanner device, and the image forming conditions are adjusted. Thus, calibration for obtaining a predetermined density has been widely introduced.

  This calibration creates a plurality of reference patches based on a plurality of input image signals on a sheet as a reference chart, detects the reference patch density created on the sheet, compares it with the target density, and detects the detected reference patch density. This is done by creating gradation correction data for correcting the input image signal so as to match the target density.

  Japanese Patent Application Laid-Open No. 2004-151561 discloses a technique for discriminating whether or not correction is applied based on gradation correction data between a copy image and a printer image. Patent Document 2 discloses a scanner calibration technique for correcting individual differences between scanners used for printer calibration. Patent Document 3 discloses a technique in which calibration is performed while maintaining good color reproducibility by executing toner density control before performing calibration.

JP-A-10-145597 JP 2001-080180 A Japanese Patent Laying-Open No. 2005-091767

  The present invention has been made from the above-described background, and an object thereof is to provide an image forming apparatus capable of performing highly accurate calibration (gradation correction).

[Image forming apparatus]
In order to achieve the above object, an image forming apparatus of the present invention includes an image reading unit that reads a document and converts it into image data,
First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction for correcting the gradation of image data other than the image data read by the image reading means First storage means for storing data;
Other than the image data read by the image reading means, the gradation of the image data read by the image reading means is corrected based on the first gradation correction data stored in the first storage means. Gradation correction means for correcting the gradation of the image data based on the second gradation correction data;
Image output means for outputting an image formed based on the image data after gradation correction is performed by the gradation correction means;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The first gradation correction data is created based on the image data of the test image read by the image reading means, and the second storage is based on the image data of the test image read by the image reading means. Gradation correction data creating means for creating the second gradation correction data by applying the image reading means correction data stored in the means and storing the second gradation correction data in the first storage means.

  Preferably, the gradation correction data creation means is common to the test image for creating the first gradation correction data and the test image for creating the second gradation correction data, and the image reading means. The first and second gradation correction data are created by the same process based on the image data of the common test image read by the above.

The image forming apparatus of the present invention includes an image reading unit that reads a document and converts it into image data,
First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction for correcting the gradation of image data other than the image data read by the image reading means First storage means for storing data;
Other than the image data read by the image reading unit, the tone of the image data read by the image reading unit is corrected based on the first tone correction data stored in the first storage unit. Gradation correction means for correcting the gradation of the image data based on the second gradation correction data;
Image output means for outputting an image formed based on the image data after gradation correction is performed by the gradation correction means;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Selection means for selecting whether to apply the image reading means correction data stored in the second storage means when the first or second gradation correction data is created;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
Based on the image data of the test image read by the image reading means and the selection result of the selection means, the first and second gradation correction data are created and stored in the first storage means. Tone correction data creating means.

Preferably, the image reading unit adds information specifying the image reading unit as attribute data to the read image data,
The gradation correction unit extracts attribute data from image data to be subjected to gradation correction, and whether or not the image data is image data read by the image reading unit based on the extracted attribute data Determine whether.

The image forming apparatus of the present invention includes a plurality of image reading units that read a document and convert it into image data,
First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction for correcting the gradation of image data other than the image data read by the image reading means First storage means for storing data;
The gradation of the image data read by an image reading unit among the plurality of image reading units is a corresponding first of the plurality of first gradation correction data stored in the first storage unit. A gradation correction unit that corrects the gradation of image data other than the image data read by the plurality of image reading units based on the second gradation correction data.
Image output means for outputting an image formed based on the image data after gradation correction is performed by the gradation correction means;
A second storage means for storing a plurality of image reading means correction data for correcting the gradation characteristics of the plurality of image reading means, respectively;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The plurality of first gradation correction data are respectively created based on the image data of the test image read by the plurality of image reading means, and read by an image reading means of the plurality of image reading means. Based on the image data of the test image, the second gradation correction data is created by applying corresponding image reading means correction data among a plurality of image reading means correction data stored in the second storage means. And gradation correction data creating means stored in the first storage means.

Preferably, the plurality of image reading units add information specifying the image reading unit to the read image data as attribute data,
The gradation correction unit extracts attribute data from image data to be subjected to gradation correction, and sets the image reading unit from which the image data is read based on the extracted attribute data to the plurality of image reading units. First, the first gradation correction data corresponding to the specified image reading means is selected.

  Preferably, the apparatus further includes image reading means correction data creating means for creating image reading means correction data based on the reference document image read by the image reading means and storing it in the second storage means.

[Printer calibration device]
In the printer calibration apparatus of the present invention, the first gradation correction data for correcting the gradation of the image data read by the image reading means and the gradation of the image data other than the image data read by the image reading means. First storage means for storing second gradation correction data to be corrected;
An image other than the image data read by the image reading unit by correcting the gradation of the image data read by the image reading unit based on the first tone correction data stored in the first storage unit. Gradation correction means for correcting the gradation of data based on the second gradation correction data;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The first gradation correction data is created based on the image data of the test image read by the image reading means, and is stored in the second storage means based on the image data of the test image read by the image reading means. Gradation correction data creating means for creating the second gradation correction data by applying the stored image reading means correction data and storing the second gradation correction data in the first storage means.

  Preferably, the gradation correction data creation means is common to the test image for creating the first gradation correction data and the test image for creating the second gradation correction data, and the image reading means. The first and second gradation correction data are created by the same process based on the image data of the common test image read by the above.

The printer calibration apparatus of the present invention also includes first gradation correction data for correcting the gradation of image data read by the image reading means and the gradation of image data other than the image data read by the image reading means. First storage means for storing second gradation correction data for correcting
An image other than the image data read by the image reading unit by correcting the gradation of the image data read by the image reading unit based on the first tone correction data stored in the first storage unit. Gradation correction means for correcting the gradation of data based on the second gradation correction data;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Selection means for selecting whether to apply the image reading means correction data stored in the second storage means when the first or second gradation correction data is created;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
A gradation which creates the first and second gradation correction data based on the image data of the test image read by the image reading means and the selection result of the selection means and stores the first and second gradation correction data in the first storage means Correction data creating means.

  Preferably, the gradation correction unit extracts attribute data, which is information for specifying the image reading unit used when the image data is read, from the image data to be subjected to gradation correction. Based on the extracted attribute data, it is determined whether or not the image data is image data read by the image reading means.

The printer calibration apparatus of the present invention also includes first gradation correction data for correcting the gradation of image data read by the image reading means and the gradation of image data other than the image data read by the image reading means. First storage means for storing second gradation correction data for correcting
The gradation of the image data read by an image reading means among the plurality of image reading means is a first corresponding to the first of the plurality of first gradation correction data stored in the first storage means. Gradation correction means for correcting based on the gradation correction data and correcting the gradation of image data other than the image data read by the plurality of image reading means based on the second gradation correction data;
A second storage means for storing a plurality of image reading means correction data for respectively correcting the gradation characteristics of the plurality of image reading means;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The plurality of first gradation correction data are respectively created based on the image data of the test image read by the plurality of image reading means, and the image read by a certain image reading means among the plurality of image reading means Based on the image data of the test image, the second gradation correction data is created by applying the corresponding image reading means correction data among the plurality of image reading means correction data stored in the second storage means. Gradation correction data creating means stored in the first storage means.

  Preferably, the gradation correction unit extracts attribute data, which is information for specifying the image reading unit used when the image data is read, from the image data to be subjected to gradation correction. Based on the extracted attribute data, an image reading unit from which the image data has been read is specified from among a plurality of image reading units, and first gradation correction data corresponding to the specified image reading unit is selected.

  Preferably, the image forming apparatus further includes image reading means correction data creating means for creating image reading means correction data based on the reference original image read by the image reading means and storing the data in the second storage means.

  As described above, according to the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, even when the gradation characteristics of the image output means are made to coincide with the target gradation characteristics by the scanner calibration function during the printer calibration, the copy original having reproducibility as a copying system It is possible to obtain an effect that the relationship between the density and the copy density can be made as intended.

  According to a second aspect of the present invention, the image reading is performed by commonly using the test image for creating the first gradation correction data and the test image for creating the second gradation correction data. Since the first and second gradation correction data are created simultaneously based on the image data of the common test image read by the means, it is possible to reduce the process of creating the gradation correction data. It becomes.

  According to the third aspect of the present invention, it is possible to select whether or not to apply the image reading unit correction data when creating the gradation correction data. It is possible to appropriately cope with a system configuration in which the image reading means to be read is different.

  According to the fourth aspect of the invention, the attribute data for specifying the image reading means used at the time of reading is added to the image data, so that the read image data is output after being stored. Even in this case, the gradation correction unit determines whether the image data to be subjected to gradation correction is image data read by the image reading unit or other image data, and the first and second image data are determined. It is possible to appropriately select gradation correction data to be used for gradation correction from the gradation correction data.

  According to the fifth aspect of the present invention, it is possible to cope with a case where a plurality of image reading means exist by creating gradation correction data for a copy image for each image reading means.

  According to the sixth aspect of the present invention, the attribute data for specifying the image reading means used at the time of reading is added to the image data, so that the read image data is output after being stored. Even in this case, the corresponding gradation correction data can be appropriately selected from the plurality of gradation correction data.

[background]
First, in order to help understanding of the present invention, its background and outline will be described.

  As described above, in an image forming apparatus such as a copying machine or a printer, calibration processing is performed to correct fluctuations in image density due to environmental changes such as temperature and humidity and changes with time. An example of an image forming apparatus that performs such calibration is shown in FIG.

  As shown in FIG. 1, the image forming apparatus includes a scanner unit 300, an image processing unit 310, a communication interface (IF) 320, and a printer unit 330. The image processing unit 310 includes a gradation correction data creation unit 316, a gradation correction data storage unit 312, a gradation correction processing unit 313, and a test image data storage unit 317.

  The scanner unit 300 functions as an image reading unit that reads a set original and converts it into image data.

  The tone correction data creation unit 316 creates tone correction data based on the image data of the test image read by the scanner unit 300 and stores it in the tone correction data storage unit 312.

  The gradation correction data storage unit 312 stores gradation correction data for correcting the gradation of image data printed by the printer unit 330.

  The gradation correction processing unit 313 stores the gradation of the image data read by the scanner unit 300 and the gradation of the image data instructed to be printed from the external device via the communication IF 320 in the gradation correction data storage unit 312. The correction is made based on the tone correction data and output to the printer unit 330.

  The test image data storage unit 317 stores test image data including a plurality of reference patches having different densities.

  The communication IF 320 receives image data instructed to be printed from an external device such as a computer or a server, and outputs the image data to the gradation correction processing unit 313 as image data for printing.

  The printer unit 330 prints an image formed based on the image data after the gradation correction is performed by the gradation correction processing unit 313.

  Next, a calibration operation performed by such an image forming apparatus will be described with reference to the flowchart of FIG.

  First, when the start of the calibration process is instructed, the test image data storage unit 317 outputs test image data including a plurality of reference patches having different densities to the printer unit 330 and forms it on a recording sheet such as a printing sheet. (S401). An example of this test image is shown in FIG. In the example shown in FIG. 3, the test image is composed of reference patches whose input image signal levels are 5% to 100%, respectively.

  When the user sets the recording paper on which the test image is formed on the scanner unit 300 of the image forming apparatus and gives an instruction to start image reading, the scanner unit 300 reads the test image (S402). Then, the gradation correction data creation unit 316 detects the density of each reference patch from the image data of the read test image (S403). Then, the gradation correction data creation unit 316 compares the detected density of each reference patch with the target density, and creates gradation correction data based on the comparison result (S404).

  An example of the gradation correction data created in this way is shown in FIG. In FIG. 4, the left scale on the vertical axis indicates the density, and the right scale indicates the output image signal level.

  In the example shown in FIG. 4, the measured image density obtained by reading the test image has become higher than the set target image density. Therefore, the gradation correction data creation unit 316 creates gradation correction data that reduces the density, and the gradation correction processing unit 313 performs gradation correction based on the gradation correction data. Referring to FIG. 4, it can be seen that when the gradation correction of the measured image density is performed based on the gradation correction data, the corrected image density approaches the target image density.

  However, in an image forming apparatus that performs such calibration, tone correction data is created on the assumption that no error is included in the reading accuracy of the scanner unit 300 for reading a test image. For this reason, if an error is included when each reference patch of the test image is read by the scanner unit 300, calibration cannot be performed correctly.

  The reason why such a problem occurs will be described with reference to FIG. Here, the gradation characteristic of the scanner unit 300 includes an error of the gradation characteristic of β times that of the target scanner device, and the gradation characteristic of the printer unit 330 includes an error of the target gradation characteristic of α times. Shall be. Note that the error in the gradation characteristics is not simply indicated by the magnification, but here it is indicated by the magnification for the sake of simplicity.

  Further, operations in the image forming apparatus shown in FIG. 5 will be sequentially described with reference to FIG.

  (1) First, when printer calibration is started, the test image data storage unit 317 instructs the printer unit 330 to print a test image. Then, the printer unit 330 prints a test image, and the gradation characteristics of the test image include an error of α times.

  (2) When this test image is read by the scanner unit 300, the read image data includes both the gradation characteristic error α of the printer unit 330 and the error β of the scanner unit 300. Will occur.

  (3) Therefore, since the gradation correction data creation unit 316 creates gradation correction data based on the test image data with an error of αβ, the characteristic of the gradation correction data is 1 / αβ.

  (4) Therefore, when image data for printing is output to the gradation correction processing unit 313 via the communication IF 320, the gradation correction processing unit 313 stores the gradation stored in the gradation correction data storage unit 312. Gradation correction is performed based on the correction data (1 / αβ) and output to the printer unit 330. As a result, although the tone characteristic error α in the printer unit 330 is canceled, the effect of the tone characteristic error β of the scanner unit 300 remains as it is, and the tone characteristic of the print image becomes 1 / β.

  In order to solve such a problem, the configuration of the image forming apparatus in which the calibration for calibrating the measurement sensitivity of the scanner unit 300 for reading the test image is performed before the calibration of the printing unit 330 is shown in FIG. Shown in

  In the following description, calibration for the print unit 330 is referred to as printer calibration, and calibration for the scanner unit 300 is referred to as scanner calibration.

  As shown in FIG. 7, the image forming apparatus includes a scanner unit 300, an image processing unit 340, a communication interface (IF) 320, and a printer unit 330. In FIG. 7, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

Here, the image processing unit 340 has a scanner correction data creation unit 314 and a scanner correction data storage unit 315 added to the image processing unit 310 in the image forming apparatus shown in FIG. The unit 316 is replaced with a gradation correction data creation unit 311.

  The scanner correction data storage unit 315 has a function for storing scanner correction data for correcting the gradation characteristics of the scanner unit 300.

  The scanner correction data creation unit 314 creates scanner correction data based on the image data of the reference document image created by offset printing or the like, and stores it in the scanner correction data storage unit 315.

  The reference document image is created by offset printing the same image as the printer calibration test image as shown in FIG. 3, and is composed of a plurality of reference patches having different image densities as shown in FIG. Yes. In FIG. 3, only one color is shown for the sake of simplicity, but in actuality, an image is displayed for each color of yellow, magenta, cyan, and black. A plurality of reference patches having different densities are configured.

  The gradation correction data creation unit 311 stores the image data of the test image read by the scanner unit 300 in the scanner correction data storage unit 315 in addition to the function of the gradation correction data creation unit 316 shown in FIG. It has a function to correct by the scanner correction data.

  Here, the scanner calibration is described as performing correction using the scanner correction data on the image data of the read test image. However, the scanner correction data is applied to the gradation target value. Alternatively, the scanner correction data may be applied to the created gradation correction data.

  Next, the flow of the scanner calibration process will be described with reference to the flowchart of FIG.

  First, the scanner unit 300 reads a reference document for scanner calibration created by offset printing (S201). Then, the scanner correction data creation unit 314 calculates the density of the read image data of the reference original image (S202), creates scanner correction data based on the calculation result, and stores it in the scanner correction data storage unit 315. (S203).

  Next, FIG. 9 shows an example of measurement results obtained by measuring the reference document image, and FIG. 10 shows an example of scanner correction data created based on the measurement results. Here, a description will be given using a case where correction of two scanners, scanner A and scanner B, is performed.

  As shown in FIG. 9, with respect to the target value measured by a standard scanner device having standard measurement sensitivity, the scanner A measures the reference document on the side where the measured value is large (dark side), and the scanner B measures the reference document. The value is measured on the smaller side (thin side).

  Therefore, as shown in FIG. 10, the scanner correction data for scanner A is set to reduce (thin) the density of the input image data, and the scanner correction data for scanner B is set to the density of the input image data. Is set to be larger (darker). That is, the scanner correction data of the scanner A that measures the gradation of the test image darkly corrects the input value, and conversely, the scanner correction data of the scanner B that measures the gradation of the test image thinly changes the input value. By making a large correction, a process for matching the measurement result of each scanner device with the characteristics of the standard scanner device is performed.

  According to the image forming apparatus in which such scanner calibration is performed, the image data of the test image read by the scanner unit 300 is subjected to gradation correction by the scanner correction data. This makes it possible to perform printer calibration.

  By performing such scanner calibration, the measurement sensitivity difference of each scanner device is corrected not only when the test image is read by an external scanner device but also by a scanner device provided in the image forming apparatus. Even when any scanner device is used, it is possible to obtain highly accurate gradation correction data.

  However, the conventional scanner calibration is only to calibrate the measurement sensitivity when measuring a test image for printer calibration, and it is a measurement when reading a normal image for copying. Sensitivity cannot be calibrated. The reason for this will be described below.

  In the scanner calibration / printer calibration, only the CMYK single colors are targeted, so the accuracy of the secondary and tertiary colors in which the CMYK colors overlap is not considered. Therefore, the scanner correction data and the gradation correction data are one-dimensional curves for correcting the gradation for each color. However, the image read by the scanner unit 300 for copying naturally includes secondary and tertiary colors. The RGB image data read by the scanner unit 300 is converted into L * a * b * image data by multidimensional matrix calculation, and after various image processing is performed, the toner of the printer unit 330 is further calculated by multidimensional matrix calculation. The data is converted into data corresponding to each color of CMYK. For this reason, even if the RGB image data obtained by the scanner unit 300 is simply corrected with the one-dimensional scanner correction data, the subsequent two-dimensional multi-dimensional matrix calculation cannot be handled. For this reason, the scanner calibration is only intended to correct the measurement sensitivity when measuring a test image for performing printer calibration.

  That is, when a normal image is read by the scanner device that has been subjected to scanner calibration, the reading sensitivity difference is not calibrated.

  An image forming apparatus that performs the printer calibration and matches the gradation characteristics of the printer unit with the target gradation characteristics includes not only a printing function for printing image data from an external device such as a computer or a server, but also an image forming apparatus. Some of them have a copying function that scans an original with a scanner device connected to the outside or a scanner device connected to the outside and prints it with a printer unit.

  In such an image forming apparatus, it is conceivable that a scanner apparatus that reads a test image for performing printer calibration and a scanner apparatus that reads a document to be copied are shared. In such a case, there arises a problem that the scanner calibration function has an adverse effect and the copy reproduction characteristics deteriorate. Here, the copy reproduction characteristic indicates a characteristic of how much the copy original density and the copy density (the density of the copied original) match. Here, the copy original density and the copy density match. Is ideal.

  As described above, the scanner calibration function creates scanner correction data that makes the value measured by printer calibration thinner for scanners that measure darker, and printer calibration for scanners that measure thinner. An object of the present invention is to make the gradation characteristics of the printer device match the target gradation characteristics by creating scanner correction data that darkens the values measured in the measurement. However, when the same scanner device as the scanner device used for printer calibration is used as a copy scanner, if the tone characteristics of the printer device are matched with the target tone characteristics by the scanner calibration function, the copy image For the density gradation characteristics, the scanner calibration function has an adverse effect, and instead the density gradation characteristics of the copy image vary.

  The reason why such a problem occurs will be described with reference to FIG. Here, as in FIG. 5, the gradation characteristic of the scanner unit 300 includes an error of the gradation characteristic of β times with respect to the target scanner device, and the gradation characteristic of the printer unit 330 includes the target gradation of α times. An error with respect to the characteristic shall be included.

  Further, operations in the image forming apparatus shown in FIG. 11 will be described in sequence with reference to FIG.

  (1) First, by performing scanner calibration, a reference document image that does not include a gradation characteristic error is read by the scanner unit 300. Here, since the scanner section 300 includes a gradation characteristic error of β times, the read reference document image data also includes an error of β.

  (2) Next, the scanner correction data creation unit 314 creates scanner correction data for correcting the measurement sensitivity of the scanner unit 300 and stores it in the scanner correction data storage unit 315. Here, since the scanner unit 300 has a measurement sensitivity error of β times, the scanner correction data is data having a characteristic of 1 / β.

  (3) Next, when printer calibration is started, the test image data storage unit 317 instructs the printer unit 330 to print a test image. Then, the printer unit 330 prints a test image, and the gradation characteristics of the test image include an error of α times.

  (4) When this test image is read by the scanner unit 300, the read image data includes both the gradation characteristic error α of the printer unit 330 and the error β of the scanner unit 300. Will occur. However, since the gradation correction data creation unit 311 performs gradation correction of the image data of the test image based on the scanner correction data (1 / β) stored in the scanner correction data storage unit 315, the test image data The error of αβ is only α.

  (5) Since the gradation correction data creation unit 311 creates gradation correction data based on the test image data having only this error α, the characteristic of the gradation correction data is 1 / α.

  The operation when a copy document is copied and the print document is printed in such an image forming apparatus will be described with reference to FIGS.

  (6) First, when print image data is output to the gradation correction processing unit 313 via the communication IF 320, the gradation correction processing unit 313 stores the gradation stored in the gradation correction data storage unit 312. Gradation correction is performed based on the correction data (1 / α) and output to the printer unit 330. Therefore, the tone characteristic error α in the printer unit 330 is canceled out, and the tone characteristic of the printed document is close to the target tone characteristic.

  (7) Next, when a copy original is read by the scanner unit 300 and a copy process is performed, the scanner unit 300 has a tone characteristic error of β. A tone characteristic error is included. When the gradation correction processing unit 313 performs gradation correction processing on the copy image data (β) based on the gradation correction data (1 / α), β / A tone characteristic error of α is included. When the printing process is performed by the printer unit 330, a tone characteristic error of β remains in the final copy output image.

  As described above, when performing printer calibration, the scanner calibration is performed so that the gradation characteristics of the printer unit match the target gradation characteristics. Therefore, it is effective when printing a print image unrelated to the scanner or a read image measured by a scanner device different from the scanner device used for printer calibration. However, in a copier that uses the same scanner device as the scanner device used for printer calibration, if the tone characteristics of the printer device are matched with the target tone characteristics by the scanner calibration function during printer calibration, the copy system There is a problem that the relationship between the copy original density and the copy density, which is the reproducibility, does not match.

[Embodiment]
Next, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 15 is a diagram showing a configuration of an image processing system including the image forming apparatus 80 according to the first embodiment of the present invention.

  As shown in FIG. 15, the image processing system includes an image forming apparatus 80 and a terminal device 60 connected via a network 70. The terminal device 60 generates print data such as a print job and transmits it to the image forming apparatus 80. The image forming apparatus 80 receives the print data transmitted from the terminal device 60 and outputs an image corresponding to the print data on the printing paper.

Next, the configuration of an image forming apparatus 80 to which the present invention is applied is shown in FIG.
As shown in FIG. 16, the image forming apparatus 80 of the present embodiment includes an image reading unit 50 and an image forming unit 40.

  The image reading unit 50 includes a platen 51 on which an original is placed, a platen cover 52, a lamp 53 that irradiates light on the original on the platen, a sensor 54 that converts the received light amount distribution into an image signal, and an original that is irradiated from the lamp. The optical system 55 collects the reflected light reflected by the image on the original surface on the CCD sensor.

  The image forming unit 40 includes four image forming units 10Y, 10M, 10C, and 10K on which toner images of yellow (Y), magenta (M), cyan (C), and black (K) are formed. And the four image forming units 10Y, 10M, 10C, 10K and the intermediate transfer belt 20 to which the toner image is primarily transferred and circulated, respectively, and the four image forming units 10Y, 10M, 10C, 10K. The primary transfer rolls 5Y, 5M, 5C, and 5K that primarily transfer the formed toner images of the respective colors to the intermediate transfer belt 20, and the toner images that are primarily transferred onto the intermediate transfer belt 20 are secondarily transferred to the paper P. Secondary transfer roll 15, three paper trays 12 a, 12 b, and 12 c that store paper P of different sizes, a manual feed portion 13 for manually feeding paper P, and a paper tray The paper P extracted from 12a, 12b, 12c or the paper P set on the manual feed section 13 is transported to the position where the secondary transfer roll 15 is disposed, and the toner image transferred onto the paper P is heated and heated. The fixing device 16 that fixes the toner image on the paper P by pressing, the transport roller 18 that discharges the paper P from the arrangement position of the secondary transfer roll 15 via the fixing device 16, and the paper P on which the toner image is fixed on one side And a transport roll 17 for transporting the paper to the position where the secondary transfer roll 15 is disposed again, and a first tray 31 and a second tray 32 for discharging the paper P on which the toner image is fixed.

  The image forming units 10Y, 10M, 10C, and 10K respectively include photosensitive drums 1Y, 1M, 1C, and 1K on which toner images are formed, and chargers 2Y and 2M that charge the photosensitive drums 1Y, 1M, 1C, and 1K. 2C, 2K, exposure unit 3 that forms an electrostatic latent image by irradiating charged photosensitive drums 1Y, 1M, 1C, and 1K with exposure light modulated based on an image signal, and electrostatic latent image Development that applies toner of each color to YMCK to form a toner image of each color, and develops an electrostatic latent image by applying toner of each color of YMCK charged by stirring the developer mixed with toner and carrier 4Y, 4M, 4C, and 4K, and cleaning devices 6Y and 6M that clean toner remaining on the photosensitive drums 1Y, 1M, 1C, and 1K after primary transfer of the toner image to the intermediate transfer belt 20. 6C, and a 6K. Note that there is a toner box 39 that stores toner of each color YMCK, and the toner of each color is supplied to the developing devices 4Y, 4M, 4C, and 4K at a predetermined timing.

  The intermediate transfer belt 20 is circulated and moved around a drive roll 21 that drives the belt, a driven roll 22, and a tension roll 23 that applies tension to the belt, and a unit 10Y that forms a Y-color toner image. A belt cleaning device 26 is provided on the upstream side.

  The image signal read by the image reading unit 50 is converted into an image signal for each YMCK color by an image processing unit (not shown).

  The image forming apparatus according to the present embodiment includes a user interface 11 for selecting various image forming modes. When an image forming mode is selected on the user interface 11, the image forming mode is automatically set and gradation is selected. In the correction processing unit 35, gradation correction processing is performed on the image signal read and converted by the image reading unit 50 using gradation correction data corresponding to the selected image forming mode.

  Then, the exposure light modulated based on the image signal subjected to the gradation correction processing from the exposure unit 3 is applied to the photosensitive drums 1Y, 1M, 1C, and 1K included in the four units 10Y, 10M, 10C, and 10K, respectively. When irradiated, an electrostatic latent image is formed on each photosensitive drum, and the electrostatic latent image is developed by each developing device 4Y, 4M, 4C, 4K to form a toner image of each color. The toner images of the respective colors are superimposed and transferred onto the intermediate transfer belt 20 by the primary transfer rolls 5Y, 5M, 5C, and 5K, and the toner image on the intermediate transfer belt 20 is transferred to the manual feed portion 13 by the secondary transfer roll 15. Alternatively, the image is transferred from the paper tray 12 to the paper P conveyed by the conveyance roll 14, further heated and pressurized by the fixing device 16, fixed on the paper P, conveyed by the conveyance roll 18, and the first tray 31 or the first tray 31. It is discharged to the second tray 32.

  When the double-sided printing mode is selected on the user interface 11, the paper P that is transported by the transporting roll 18 and has an image formed on one side is discharged to the first tray 31 or the second tray 32. The sheet P is switched back with the trailing edge of the sheet P as the leading edge, and is conveyed again by the conveying roll 17 to the position where the secondary transfer roll 15 is disposed. The toner image transferred to the other surface of the paper P by the secondary transfer roll 15 is heated and pressurized by the fixing device 16 and fixed on the paper P, and is transported by the transport roll 18 to the first tray. 31 or the second tray 32.

  The image forming unit 40 of the present embodiment has a plurality of densities for correcting gradation correction data in the image forming mode corresponding to the image forming mode selected by the user interface 11 on the photosensitive drums 1Y, 1M, 1C and 1K. The image reading unit 50 reads the test image formed by the test image forming unit and the test image forming unit that forms the reference patch image and forms the test image in which the reference patches having the plurality of densities are transferred and fixed on the sheet. Based on the reference patch density obtained in this way, gradation correction data corresponding to the selected image forming mode is created, and an image processing unit 35 for performing gradation correction processing is provided, and printer calibration as described above is executed.

  Here, the image forming apparatus according to the present exemplary embodiment includes the image reading unit 50 and is used for calibration. However, calibration can be measured by an external reading unit.

  Further, the image forming apparatus of the present embodiment has been described based on an image forming apparatus having a tandem configuration using the intermediate transfer belt 20, but the image forming apparatus is not limited to the tandem configuration and has a multiple cycle configuration. The intermediate transfer belt 20 may be used instead of the intermediate transfer belt 20. Further, the present invention is not limited to the intermediate transfer method, and can be applied to a method of directly transferring to a recording medium carried on a paper conveyance belt or a recording medium conveyed by a roll.

  Next, FIG. 17 shows a hardware configuration of the image forming apparatus 80 of the present embodiment.

  As shown in FIG. 17, the image forming apparatus 80 includes a CPU 68, a memory 69, a storage device 72 such as a hard disk drive (HDD), and a communication interface (data transmission / reception with an external computer via the network 50). IF) 74, a user interface (UI) device 76 including a touch panel or a liquid crystal display and a keyboard, a scanner 77, and a printer unit 78. These components are connected to each other via a control bus 66.

  The CPU 68 executes predetermined processing based on an image processing program stored in the memory 70 or the storage device 72 and controls the operation of the image forming apparatus 80.

  FIG. 18 is a block diagram showing a functional configuration of the image forming apparatus 80 realized by executing the above-described image processing program.

  As shown in FIG. 18, the image forming apparatus 80 according to the present embodiment includes a scanner unit 77, an image processing unit 35, a communication interface (IF) 74, and a printer unit 78. The image processing unit 35 includes a scanner correction data creation unit 91, a scanner correction data storage unit 92, a tone correction data creation unit 93, a tone correction data storage unit 94, a tone correction processing unit 95, And a test image data storage unit 96.

  The scanner unit 77 functions as an image reading unit that reads a set original and converts it into image data.

  The communication interface (IF) 74 outputs the image data instructed to be printed from the terminal device 60 to the gradation correction processing unit 95 as print image data.

  The scanner correction data storage unit 92 has a function for storing scanner correction data for correcting the gradation characteristics of the scanner unit 77.

  The scanner correction data creation unit 91 creates scanner correction data based on the image data of the reference document image created by offset printing or the like and stores it in the scanner correction data storage unit 92.

  The gradation correction data creation unit 93 creates gradation correction data for a copy (copy) image based on the image data of the test image read by the scanner unit 77, and the image of the test image read by the scanner unit 77. Based on the data, the scanner correction data stored in the scanner correction data storage unit 92 is applied to generate gradation correction data for a print image and stored in the gradation correction data storage unit 94.

  The tone correction data storage unit 94 stores the tone correction data for the copy image and the print image created by the tone correction data creation unit 93.

  Here, the gradation correction data for the copy image is gradation correction data for correcting the gradation of the image data read by the scanner unit 77, and the gradation correction data for the print image is a print image. This is gradation correction data for correcting the gradation of image data other than the image data read by the scanner unit 77 such as image data. Here, the image data other than the image data read by the scanner unit 77 means, for example, image data for printing instructed to print from an external device such as a computer or a server via the communication IF 74.

  The gradation correction processing unit 95 corrects the gradation of the copy image data read by the scanner unit 77 based on the copy image gradation correction data stored in the gradation correction data storage unit 94. Further, the gradation correction processing unit 95 stores the gradation of image data other than the image data for copying read by the scanner unit 77, here, the gradation of the print image data received via the communication IF 74, as a gradation correction data storage unit. The correction is performed based on the gradation correction data for the print image stored in the image 94.

  Note that the gradation correction processing unit 95 does not need to perform gradation correction processing on all image data to be printed by the printer unit 330. A gradation correction selection means is provided for selecting whether or not gradation correction is performed on image data to be printed. The user can perform gradation correction on image data to be output by the gradation correction selection means. It may be possible to select the presence or absence.

  The test image data storage unit 96 stores test image data composed of a plurality of reference patches having different densities. Note that the test image used when creating the gradation correction data for the copy image and the test image used when creating the gradation correction data for the print image do not necessarily have to be the same test image. It can be good or different.

  The printer unit 78 prints an image formed based on the image data after the tone correction is performed by the tone correction processing unit 95.

  Next, the operation of the image forming apparatus 80 of the present embodiment will be described in detail with reference to the drawings.

  When the image forming apparatus 80 according to the present embodiment enters the calibration mode, the display as shown in FIG. 19 is performed by the user interface device 76 as shown in FIG.

  In FIG. 19, a button 141 for instructing execution of scanner calibration, a button 142 for instructing execution of printer calibration for copy images, and an instruction for execution of printer calibration for print images. A button 143 for displaying is displayed.

  The scanner calibration may be performed immediately before the printer calibration is performed. However, the scanner calibration is performed every time the printer calibration is performed because the measurement sensitivity difference between the individual scanner devices and the change in the measurement sensitivity of the scanner device over time are calibrated. The need is low. Therefore, independently of printer calibration, scanner calibration may be performed at regular intervals such as when the image forming apparatus is installed or once a month.

  For this reason, a button 141 for performing scanner calibration and buttons 142 and 143 for performing printer calibration are provided independently.

  First, when the user operates a button 141 for instructing execution of scanner calibration, in the image forming apparatus 80 of the present embodiment, scanner calibration is performed prior to printer calibration. The scanner calibration process is the same as the process described with reference to the flowchart of FIG.

  When the user operates one of the buttons 142 and 143 for instructing execution of printer calibration, printer calibration is performed. The flow of printer calibration processing in this embodiment will be described with reference to the flowchart of FIG.

  First, when the start of the calibration process is instructed, the test image data storage unit 96 outputs a test image composed of a plurality of reference patches having different densities to the printer unit 78 and forms it on a recording sheet such as a printing sheet. (S101). This test image has the same configuration as that shown in FIG.

  When the user sets the recording paper on which the test image is formed on the scanner unit 77 of the image forming apparatus and gives an instruction to start image reading, the scanner unit 77 reads the test image (S102). Then, the gradation correction data creation unit 77 detects the density of each reference patch from the image data of the read test image (S103).

  Next, the gradation correction data creation unit 93 in this embodiment determines whether the gradation correction data for which creation has been instructed is for a copy image or a print image (S104).

  When the printer calibration instructed by the user on the user interface screen shown in FIG. 19 is for a print image, that is, when the gradation correction data instructed for creation is for a print image, the gradation correction data creation unit 93 Then, the gradation correction data is created by applying the scanner correction data stored in the scanner correction data storage unit 92 to the image data of the test image read by the scanner unit 77 (S105).

  Further, when the printer calibration instructed by the user on the user interface screen shown in FIG. 19 is for a copy image, that is, when the gradation correction data instructed to create is for a copy image, a gradation correction data creation unit 93 creates gradation correction data without applying the scanner correction data stored in the scanner correction data storage unit 92 to the image data of the test image read by the scanner unit 77 (S106).

  Next, the operation of the image forming apparatus 80 in the present embodiment will be described with reference to FIG.

  Here, the tone characteristic of the scanner unit 77 includes an error of the tone characteristic of β times the tone characteristic of the target scanner device, and the tone characteristic of the printer unit 78 is the target tone characteristic of α times. The error for Note that the error in the gradation characteristics is not simply indicated by the magnification, but here it is indicated by the magnification for the sake of simplicity.

  First, by performing scanner calibration, the scanner correction data creation unit 91 creates scanner correction data for correcting the measurement sensitivity of the scanner unit 78 and stores it in the scanner correction data storage unit 92. Here, since the scanner unit 77 has a measurement sensitivity error of β times, the scanner correction data is data having a characteristic of 1 / β.

  Next, when printer calibration is started, the test image data storage unit 96 instructs the printer unit 78 to print a test image. Then, the printer unit 78 prints a test image, and the tone characteristic of the test image includes an error of α times.

  When this test image is read by the scanner unit 77, the read image data includes both the gradation characteristic error α of the printer unit 78 and the error β of the scanner unit 77, and an error of αβ occurs. End up.

  Here, the gradation correction data creation unit 93 according to the present embodiment is based on the scanner correction data (1 / β) stored in the scanner correction data storage unit 315 when creating gradation correction data for a print image. Thus, since the tone correction of the image data of the test image is performed, the error of αβ in the test image data is only α. Since the gradation correction data creation unit 93 creates gradation correction data based on the test image data having only this error α, the characteristic of the gradation correction data for the print image is 1 / α.

  The gradation correction data creation unit 93 in the present embodiment uses the scanner correction data (1 / β) stored in the scanner correction data storage unit 315 when creating gradation correction data for a copy image. Since tone correction is not performed, the error αβ in the test image data remains unchanged. Since the gradation correction data creating unit 93 creates gradation correction data based on the test image data having the error αβ, the characteristic of the gradation correction data for the copy image is 1 / αβ.

  Then, the gradation correction processing unit 95 performs gradation correction on the copy image data (β) from the scanner unit 77 using the copy image gradation correction data (1 / αβ). The print image data received via the communication IF 74 is subjected to gradation correction using the print image gradation correction data (1 / α). As a result, the image data output from the gradation correction processing unit 95 to the printer unit 78 is image data including a gradation error of 1 / α in any case. Therefore, when both the copy image data and the print image data are finally output by the printer unit 78, the gradation characteristic error α in the printer unit 78 is canceled, and the gradation characteristic of the printed document is the target floor. It is close to the tonal characteristics.

  As described above, in the image forming apparatus 80 according to the present embodiment, even when the copy process of reading the copy original by the scanner unit 77 and printing by the print unit 78 is performed, the print process of printing the image data input via the communication IF 74. Even in the case of performing the above, the gradation characteristics of the output image coincide with the target gradation characteristics.

(Second Embodiment)
Next, an image forming apparatus according to a second embodiment of the present invention will be described.

  In the first embodiment shown in FIG. 18, the gradation correction data creation unit 93 uses the test images at different timings for the gradation correction data for the print image and the gradation correction data for the copy image. Was created.

  This is because the printer calibration corrects the gradation characteristics of the printer apparatus, and therefore needs to be performed according to the screen structure (resolution and number of gradations) in the printer apparatus. That is, in the image forming system that uses different screen structures for the copy image and the print image, the test image using each screen structure is used at different timings according to the type of image data as in the first embodiment. It is necessary to create adjustment data. However, in an image forming system that uses the same screen structure for a copy image and a print image, it is not necessary to create tone correction data for a copy image and tone correction data for a print image at different timings.

  Therefore, the gradation correction data creation unit 93 according to the present embodiment, when the screen structure of the copy image data read by the scanner unit 77 and the screen structure of the print image data are the same, the gradation correction data for the copy image. And tone correction data for the print image are created by the same process using the same test image. Here, the test image to be used may be the same test image for the copy and printer with the same screen structure, or a test in which different patches are arranged on a single sheet of paper. An image may be used.

  As described above, in the image forming apparatus according to the present embodiment, two types of gradation correction data are created simultaneously when the scanner correction data is applied and when the scanner correction data is not applied at the time of one printer calibration.

  In the image forming apparatus according to the present embodiment, one button 161 for instructing execution of scanner calibration and one button 162 for instructing execution of printer calibration are displayed as in the user interface shown in FIG. Has been.

  When the button 162 for instructing execution of printer calibration is operated, the gradation correction data for the copy image and the gradation correction data for the print image are created at the same timing.

  The operation of the image forming apparatus of this embodiment will be described with reference to the flowchart of FIG.

  In the flowchart of FIG. 23, the steps from S101 to S103 are the same as those in the flowchart of the first embodiment shown in FIG.

  Further, the basic configuration of the image forming apparatus of the present embodiment is the same as the configuration of the image forming apparatus of the first embodiment shown in FIG. The image forming apparatus of the embodiment will be described.

  The tone correction processing unit 95 creates tone correction data for a copy image without applying scanner correction data (S174), and creates tone correction data for a print image by applying the scanner correction data (S174). S175). The created gradation correction data for the copy image and the print image are stored in the gradation correction data storage unit 94, respectively.

  Note that either of the steps of S174 and S175 may be processed first, so the order of the processes of S175 and S174 may be reversed.

(Third embodiment)
Next, an image forming apparatus according to a third embodiment of the present invention will be described.

  In the image forming apparatuses of the first and second embodiments, the gradation correction data creation unit 93 applies the scanner correction data when performing printer calibration for a printer image, and performs the printer calibration for a copy image. Did not apply scanner correction data. However, if the presence / absence of application of scanner correction data is fixed in this way, gradation correction may not be performed properly depending on the system configuration.

  For example, there is a case in which another scanner device is connected to the image forming apparatus having the scanner device, and a printer is calibrated by reading a test image using the connected scanner device. In such a system configuration, the copy document image is read by a scanner device provided in the image forming apparatus, and therefore, the scanner device that reads the test image is different from the scanner device that reads the copy document image.

  Therefore, if the gradation correction data for the copy image is created in the gradation correction data creation unit, if the scanner correction data is not applied, the gradation characteristics of the scanner device connected to the outside and the image forming apparatus are provided. If the tone characteristics of the scanner device are different, the final tone characteristics will deviate significantly from the target value.

  For this reason, the image forming apparatus according to the present embodiment can select whether or not to apply the scanner correction data when the printer calibration is performed and the gradation correction data is generated.

  The configuration of the image forming apparatus of this embodiment is shown in FIG. As shown in FIG. 24, the image forming apparatus of this embodiment is different from the image forming apparatus of the first embodiment shown in FIG. 18 in that an application presence / absence selection unit 301 is added. .

The application presence / absence selection unit 301 selects the presence / absence of application of scanner correction data when performing printer calibration. The gradation correction data creation unit 93 according to the present embodiment uses the selection result of the application presence / absence selection unit 301 as a result of selection. Based on this determination result, gradation correction data for printer image and copy image is created based on the determination result.

  An example of a user interface display in the image forming apparatus of this embodiment is shown in FIG.

  The example shown in FIG. 25 is different from the user interface shown in FIG. 19 in that an on button 191 and an off button 192 for selecting whether to apply scanner calibration are provided.

(Fourth embodiment)
Next, an image forming apparatus according to a fourth embodiment of the present invention will be described.

  As described in the third embodiment, another scanner device may be externally connected to the image forming apparatus having the scanner device. In the case of such a system configuration, a plurality of scanner devices exist in the image forming apparatus.

  The image forming apparatus of the present embodiment is an application of the present invention in the case of a system configuration in which a plurality of scanner apparatuses exist as described above. Here, in order to simplify the description, it is assumed that two scanner devices, scanner device A and scanner device B, exist in the image forming system.

  An example of user interface display in the image forming apparatus of the present embodiment is shown in FIG.

  In this embodiment, the scanner calibration can be performed for each of the scanner apparatuses A and B. In the example shown in FIG. 26, the scanner A button for instructing the scanner calibration to be performed for each of the scanner apparatuses A and B. 211 and a scanner B button 212 are provided. When the scanner A and B buttons 211 and 212 are operated, scanner calibration is performed for each of the scanner apparatuses A and B, and scanner correction data for scanner A and scanner correction data for scanner B are created.

  When performing printer calibration, the buttons 213 to 215 can be selected to apply the scanner correction data for the scanner A or the scanner B or not to apply the scanner correction data. .

  For example, when the scanner correction data for the scanner device A is applied to the test image data read by the scanner device A, the tone correction data for the print image from which the tone error of the scanner device is eliminated is created. In addition, even when the scanner correction data for the scanner device B is applied to the test image data read by the scanner device B, the tone correction data for the print image that eliminates the tone error of the scanner device is created.

  Further, when any scanner correction data is not applied to the test image data read by the scanner apparatus A, gradation correction data for a copy image when copying is performed by the scanner apparatus A is created. When no scanner correction data is applied to the test image data read by the scanner device B, gradation correction data for a copy image when copying is performed by the scanner device B is created.

  In such a case, two types of gradation correction data for the copy image are created: data corresponding to the scanner device A and data corresponding to the scanner device B.

  Then, when copying using the scanner apparatus A, the gradation correction processing unit performs gradation correction using the gradation correction data for the copy image corresponding to the scanner apparatus A. When copying using the scanner apparatus B, the gradation correction processing unit performs gradation correction using the gradation correction data for the copy image corresponding to the scanner apparatus B.

  According to the image forming apparatus of the present embodiment, when performing printer calibration, according to the scanner sensitivity of each of the scanner apparatus used when reading the test image and the scanner apparatus provided in the image forming system, Since the user can select whether or not to apply the scanner calibration function, it is possible to perform gradation correction with high accuracy.

(Fifth embodiment)
Next, an image forming apparatus according to a fifth embodiment of the present invention will be described.

  In the image forming apparatuses according to the first to fourth embodiments, the gradation correction processing unit performs gradation according to whether the image data to be printed is image data for copying or image data for printing. Tone correction data used for correction was switched. However, in some cases, image data read by a scanner device provided in the image forming apparatus is stored in a terminal device such as a personal computer, and the image data is printed at a later date. In such a case, even if it is image data for printing, it should be possible to realize highly accurate gradation correction by performing gradation correction processing using gradation correction data for copy images.

  Further, when there are a plurality of scanner devices as in the fourth embodiment, it is necessary to select gradation correction data to be used according to which scanner device has read the data.

  In order to save such time and effort, in this embodiment, information specifying the scanner device used at the time of reading is added as attribute data to the image data read by the scanner device.

  The gradation correction processing unit extracts the attribute data from the image data, and selects and uses the gradation correction data for performing the gradation correction according to the extracted attribute data.

  With such a configuration, the optimum gradation correction data is automatically selected even if the user memorizes that the image data was read by which scanner device and does not specify at the time of printing. Will be.

[Modification]
In the above embodiment, the case where the gradation correction processing unit is provided inside the image processing unit has been described, but the present invention is not limited to this, and the gradation correction processing unit is the image processing unit. The present invention can also be applied to the case of being provided outside the printer or the case of being provided inside the printer unit.

  In the above embodiment, the scanner correction data creation unit, the scanner correction data storage unit, the gradation correction data creation unit, and the gradation correction data storage unit for performing printer calibration and scanner calibration are provided in the image processing unit. However, the present invention is not limited to such a configuration.

  A printer calibration apparatus may be configured by the scanner correction data creation unit, the scanner correction data storage unit, the gradation correction data creation unit, and the gradation correction data storage unit, and may be provided outside the image processing unit. . The calibration device may be configured outside the image forming apparatus. The calibration apparatus configured as described above is used by being connected to the image forming system.

  Furthermore, in the above embodiment, the gradation correction data creation unit only selects whether to apply scanner correction data during printer calibration, but the present invention is limited to such processing. It is not something. For example, the gradation correction data creation unit does not apply the scanner correction data as it is, but applies only 50% of the difference from the correction data of the standard scanner and corrects only 50% of the measurement sensitivity difference of the scanner. You may do it.

1 is a diagram illustrating an example of an image forming apparatus that performs calibration. FIG. 6 is a flowchart for explaining a calibration process performed in the image forming apparatus. It is a figure which shows an example of the test image used for a calibration process. It is a figure which shows an example of the gradation correction data produced by the gradation correction data creation part 316. FIG. 2 is a diagram for explaining an operation of the image forming apparatus illustrated in FIG. 1. FIG. 6 is a diagram for sequentially explaining the operation of the image forming apparatus shown in FIG. 5. 1 is a diagram illustrating a configuration of an image forming apparatus that performs scanner calibration. FIG. It is a flowchart for demonstrating the process of scanner calibration. It is a figure which shows an example of the measurement result which measured the reference original image. It is a figure which shows an example of the scanner correction data produced based on the measurement result which measured the reference | standard original image. It is a figure for demonstrating operation | movement of the image forming apparatus shown in FIG. FIG. 12 is a diagram for sequentially explaining the operation of the image forming apparatus illustrated in FIG. 11. FIG. 8 is a diagram for explaining operations when a copy original is copied and image data for printing is printed in the image forming apparatus shown in FIG. 7. FIG. 14 is a diagram sequentially illustrating operations of the image forming apparatus illustrated in FIG. 13. 1 is a diagram illustrating a configuration of an image processing system including an image forming apparatus 80 according to a first embodiment of the present invention. The configuration of an image forming apparatus 80 to which the present invention is applied is shown in FIG. It is a figure which shows the hardware constitutions of the image forming apparatus 80 of the 1st Embodiment of this invention. FIG. 2 is a block diagram showing a functional configuration of an image forming apparatus 80 according to the first embodiment of the present invention. 6 is a diagram illustrating an example of display by a user interface device 76 in the image forming apparatus 80 according to the first embodiment of the present invention. FIG. 3 is a flowchart showing an operation of the image forming apparatus 80 according to the first embodiment of the present invention. It is a figure for demonstrating operation | movement of the image forming apparatus 80 of the 1st Embodiment of this invention. It is a figure which shows an example of the user interface display in the image forming apparatus of the 2nd Embodiment of this invention. 6 is a flowchart illustrating an operation of the image forming apparatus according to the second exemplary embodiment of the present invention. It is a block diagram which shows the function structure of the image forming apparatus of the 3rd Embodiment of this invention. It is a figure which shows an example of the user interface display in the image forming apparatus of the 3rd Embodiment of this invention. It is a figure which shows an example of the user interface display in the image forming apparatus of the 4th Embodiment of this invention.

Explanation of symbols

1Y, 1M, 1C, 1K Photosensitive drum 2Y, 2M, 2C, 2K Charger 3 Exposure unit 4Y, 4M, 4C, 4K Developer 5Y, 5M, 5C, 5K Primary transfer roll 6Y, 6M, 6C, 6K Cleaning Apparatus 10Y, 10M, 10C, 10K Image forming unit 11 User interface 12a, 12b, 12c Paper tray 13 Manual feed section 14 Transport roll 15 Secondary transfer roll 16 Fixing device 17, 18, 19 Transport roll 20 Intermediate transfer belt 21 Drive roll 22 Follower Roll 23 Tension Roll 31 First Tray 32 Second Tray 35 Gradation Processing Unit 39 Toner Box 40 Image Forming Unit 42 User Interface Screen 50 Image Reading Unit 51 Platen 52 Platen Cover 53 Lamp 54 Sensor 55 Optical System 60 Terminal Device 66 Control bus 6 8 CPU
69 Memory 70 Network 72 Storage Device 74 Communication Interface (IF)
76 User Interface (UI) Device 77 Scanner Unit 78 Printer Unit 80 Image Forming Device 91 Scanner Correction Data Creation Unit 92 Scanner Correction Data Storage Unit 93 Gradation Correction Data Creation Unit 94 Gradation Correction Data Storage Unit 95 Gradation Correction Processing Unit 96 Test image data storage unit 141 Scanner calibration execution button 142, 143 Printer calibration execution button 161 Scanner calibration execution button 162 Printer calibration execution button 191 On button 192 Off button 211 Scanner A button 212 Scanner B button 213 Scanner A on button 214 Scanner B ON button 215 OFF button 300 Scanner unit 301 Applicability selection unit 310 Image processing unit 311 Gradation correction data creation unit 312 Gradation correction Over data storage unit 313 gradation correction processing unit 314 scanner correction data creation unit 315 scanner correction data storage unit 316 gradation correction data creation unit 317 the test image data storage unit 320 communication interface (IF)
330 Printer Unit 340 Image Processing Unit S101 to S106 Steps S174 and S175 Steps S201 to S203 Steps S401 to S404 Steps

Claims (14)

Image reading means for reading a document and converting it into image data;
First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction for correcting the gradation of image data other than the image data read by the image reading means First storage means for storing data;
Other than the image data read by the image reading unit, the tone of the image data read by the image reading unit is corrected based on the first tone correction data stored in the first storage unit. Gradation correction means for correcting the gradation of the image data based on the second gradation correction data;
Image output means for outputting an image formed based on the image data after gradation correction is performed by the gradation correction means;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The first gradation correction data is created based on the image data of the test image read by the image reading means, and the second storage is based on the image data of the test image read by the image reading means. Gradation correction data creating means for applying the image reading means correction data stored in the means to create the second gradation correction data and storing it in the first storage means;
An image forming apparatus.   The gradation correction data creating means has the same test image for creating the first gradation correction data and the test image for creating the second gradation correction data, and is read by the image reading means. The image forming apparatus according to claim 1, wherein the first and second gradation correction data are created by the same process based on the image data of the common test image. Image reading means for reading a document and converting it into image data;
First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction for correcting the gradation of image data other than the image data read by the image reading means First storage means for storing data;
Other than the image data read by the image reading unit, the tone of the image data read by the image reading unit is corrected based on the first tone correction data stored in the first storage unit. Gradation correction means for correcting the gradation of the image data based on the second gradation correction data;
Image output means for outputting an image formed based on the image data after gradation correction is performed by the gradation correction means;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Selection means for selecting whether to apply the image reading means correction data stored in the second storage means when the first or second gradation correction data is created;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
Based on the image data of the test image read by the image reading means and the selection result of the selection means, the first and second gradation correction data are created and stored in the first storage means. Adjustment data creation means,
An image forming apparatus. The image reading means adds information specifying the image reading means to the read image data as attribute data,
The gradation correction unit extracts attribute data from image data to be subjected to gradation correction, and whether or not the image data is image data read by the image reading unit based on the extracted attribute data 4. The image forming apparatus according to claim 1, wherein the image forming apparatus determines whether or not. A plurality of image reading means for reading a document and converting it into image data;
First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction for correcting the gradation of image data other than the image data read by the image reading means First storage means for storing data;
The gradation of the image data read by an image reading unit among the plurality of image reading units is a corresponding first of the plurality of first gradation correction data stored in the first storage unit. A gradation correction unit that corrects the gradation of image data other than the image data read by the plurality of image reading units based on the second gradation correction data.
Image output means for outputting an image formed based on the image data after gradation correction is performed by the gradation correction means;
A second storage means for storing a plurality of image reading means correction data for correcting the gradation characteristics of the plurality of image reading means, respectively;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The plurality of first gradation correction data are respectively created based on the image data of the test image read by the plurality of image reading means, and read by an image reading means of the plurality of image reading means. Based on the image data of the test image, the second gradation correction data is created by applying corresponding image reading means correction data among a plurality of image reading means correction data stored in the second storage means. Gradation correction data creation means stored in the first storage means;
An image forming apparatus. The plurality of image reading means add information specifying the image reading means to the read image data as attribute data,
The gradation correction unit extracts attribute data from image data to be subjected to gradation correction, and sets the image reading unit from which the image data is read based on the extracted attribute data to the plurality of image reading units. 6. The image forming apparatus according to claim 5, wherein the first gradation correction data corresponding to the specified image reading means is selected from among them.   7. The image reading unit correction data creating unit for creating image reading unit correction data based on the reference document image read by the image reading unit and storing the image reading unit correction data in the second storage unit. 2. An image forming apparatus according to item 1. First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction data for correcting the gradation of image data other than the image data read by the image reading means First storage means for storing
An image other than the image data read by the image reading unit by correcting the gradation of the image data read by the image reading unit based on the first tone correction data stored in the first storage unit. Gradation correction means for correcting the gradation of data based on the second gradation correction data;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The first gradation correction data is created based on the image data of the test image read by the image reading means, and is stored in the second storage means based on the image data of the test image read by the image reading means. Gradation correction data creating means for applying the stored image reading means correction data to create the second gradation correction data and storing it in the first storage means;
A printer calibration apparatus.   The gradation correction data creating means has the same test image for creating the first gradation correction data and the test image for creating the second gradation correction data, and is read by the image reading means. 9. The printer calibration apparatus according to claim 8, wherein the first and second gradation correction data are created by the same processing based on image data of the common test image. First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction data for correcting the gradation of image data other than the image data read by the image reading means. First storage means for storing;
An image other than the image data read by the image reading unit by correcting the gradation of the image data read by the image reading unit based on the first tone correction data stored in the first storage unit. Gradation correction means for correcting the gradation of data based on the second gradation correction data;
Second storage means for storing image reading means correction data for correcting gradation characteristics of the image reading means;
Selection means for selecting whether to apply the image reading means correction data stored in the second storage means when the first or second gradation correction data is created;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
A gradation which creates the first and second gradation correction data based on the image data of the test image read by the image reading means and the selection result of the selection means and stores the first and second gradation correction data in the first storage means Correction data creation means;
A printer calibration apparatus.   The gradation correction unit extracts attribute data, which is information for specifying the image reading unit used when the image data is read, from the image data to be subjected to gradation correction. The printer calibration apparatus according to claim 8, wherein it is determined whether the image data is image data read by an image reading unit based on attribute data. First gradation correction data for correcting the gradation of the image data read by the image reading means and second gradation correction data for correcting the gradation of image data other than the image data read by the image reading means. First storage means for storing;
The gradation of the image data read by an image reading means among the plurality of image reading means is a first corresponding to the first of the plurality of first gradation correction data stored in the first storage means. Gradation correction means for correcting based on the gradation correction data and correcting the gradation of image data other than the image data read by the plurality of image reading means based on the second gradation correction data;
A second storage means for storing a plurality of image reading means correction data for respectively correcting the gradation characteristics of the plurality of image reading means;
Test image output means for outputting a test image formed based on predetermined test image data from the image output means;
The plurality of first gradation correction data are respectively created based on the image data of the test image read by the plurality of image reading means, and the image read by a certain image reading means among the plurality of image reading means Based on the image data of the test image, the second gradation correction data is created by applying the corresponding image reading means correction data among the plurality of image reading means correction data stored in the second storage means. Gradation correction data creating means stored in the first storage means;
A printer calibration apparatus.   The gradation correction unit extracts attribute data, which is information for specifying the image reading unit used when the image data is read, from the image data to be subjected to gradation correction. 13. The image reading unit from which the image data is read based on the attribute data is specified from a plurality of image reading units, and first gradation correction data corresponding to the specified image reading unit is selected. Printer calibration device.   The image reading means correction data creating means for creating image reading means correction data based on the reference original image read by the image reading means and storing it in the second storage means. The printer calibration apparatus according to the item.

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