JP2006217192A - Image processing system, image processor, image forming apparatus, image reader, information terminal device and image processing method, computer-readable recording medium with program for implementing the method stored thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform calibration without an image reader, to eliminates a mistake of a desired test chart used for the calibration, to easily confirm the cause of a fault when a serviceman repairs the fault, and to quickly repair the fault. <P>SOLUTION: This image processing system is constructed so that a read means of reading a test pattern image and additional information out of an outputted test chart which has a designated test pattern image formed by an image forming means and to which the additional information is added, a picture quality information acquisition means of acquiring picture quality information on the test chart from the test pattern image, and a determination means of determining whether an image output means is calibrated based upon the additional information and picture quality information are connected through a network. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing system, an image processing method, and a computer-readable recording medium storing a program for executing the method, and more particularly, to an image forming apparatus such as a printer connected via a network in the image processing system. Regarding calibration.

  In recent years, various types of peripheral devices such as personal computers and printers used in combination with them have become widespread, and along with this, it is possible to easily output hard copy of word processing documents and graphic images created on computers. It has become possible.

  A typical configuration in such a case is shown in FIG. An image processing system 1500 shown in FIG. 1 uses a host computer 1501 to create a page layout document such as desktop publishing (DTP), a word processor, a graphic document, and the like, and an image forming apparatus 1507 such as a laser beam printer or an inkjet printer. It is a system that prints out. The application 1502 runs on the host computer 1501, and typical examples include word processing software such as Microsoft's Word (registered trademark) and page layout software such as Adobe's PageMaker (registered trademark). .

  A digital document or the like created by these software is passed to the printer driver 1503 via an operating system (not shown) of the host computer 1501. Such a digital document is usually a collection of command data representing graphics, characters, etc. constituting one page, and these commands are passed to the printer driver 1503. This command is often described by a language system called PDL (page description language). As typical PDLs, GDI (registered trademark), PS (Postscript (registered trademark)), and the like are known. The printer driver 1503 performs processing for passing the passed PDL command to the rasterizer 1505 in the raster image processor 1504. The rasterizer 1505 develops characters, graphics, and the like expressed by the PDL command into a two-dimensional bitmap image that is actually output by the image forming apparatus 1507. That is, the bitmap image is configured as an image that fills a two-dimensional plane as a one-dimensional raster (line) repetition. The developed two-dimensional bitmap image is temporarily stored in the image memory 1506. The developed image data is sent to the image forming apparatus 1507. The image forming apparatus 1507 includes a well-known electrophotographic or ink jet image forming unit 1508, and print output is performed by forming a visible image on paper using these. In the image forming apparatus 1507, the image data in the image memory 1506 is transferred in synchronization with a synchronization signal or a clock signal necessary for operating the image forming unit 1508, or a transfer request for a specific color component signal. The

  In the conventional example as described above, in an image forming apparatus such as an image printer used for image output, the color or density of the output image may change while the output is performed over a long period of time. It is known. This is due to a change with time in image output characteristics of a printer or the like and an increase in variation between devices. For example, in the case of a printer using an electrophotographic method as an image forming method, laser exposure in an electrophotographic process, formation of a latent image on a photoreceptor, development with toner, transfer of a toner image to an output medium such as paper, heat The process of fixing due to the toner tends to be affected by the temperature and humidity around the apparatus or the aging of the components, and is caused by the change in the amount of toner finally fixed on the paper. It is known that such a change in image output characteristics is not unique to the electrophotographic system, and occurs in the same way in the ink jet system, thermal transfer system, thermal system, and other various systems.

  Conventionally, an image processing system for solving the above-described problems has been known. As an example, this is called calibration in Patent Document 1 or the like. This is because the printer outputs a test pattern 1601 composed of a predetermined patch as shown in FIG. 16, measures the density of the output pattern, and corrects the output characteristics of the image forming unit 1508 shown in FIG. It is something to try. This conventional calibration process will be described below in accordance with the operation flow shown in FIG.

  In FIG. 17, when calibration is instructed, first, the host computer 1501 in FIG. 15 sends a command for outputting the test pattern 1601 in FIG. 16 to the raster image processor 1504 (step S201). The raster image processor 1504 in FIG. 15 generates bitmap data to be output by the printer based on the passed command, and transfers it to the image forming apparatus 1507 in FIG. 15 (step S202). The image forming apparatus 1507 prints out on an output medium such as paper based on the given bitmap data (step S203). The pattern output here is cyan (C), magenta (M), yellow (Y), black corresponding to the four color toners used in the image forming apparatus 1507 as shown as a test pattern 1601 as shown in FIG. (K) Each of the test patterns has a patch in which the toner adhesion area ratio changes in 8 stages from 0% to 100%. In FIG. 16, each of the eight patches is indicated by a number from 0 to 7, and is indicated by a C patch 1602, an M patch 1603, a Y patch 1604, and a K patch 1605 as patches for each color. ing. In this way, the output test pattern 1601 has a total of 32 patches of 4 colors × 8 levels. Each density is measured using a reflection densitometer which is a measuring instrument for measuring the density of an image. Measure (step 204). The measured value (density data of each patch) is sent to the host computer 1501 in FIG. 15 (step S205). The host computer 1501 compares the measured value with a reference value stored in advance corresponding to the 32 patches (step S206), and based on this comparison, images of C, M, Y, and K colors. The content of the correction table for correcting data is updated, and this is registered in the table conversion unit (not shown) of the raster image processor 1504 in FIG. 15, thereby completing the calibration (step S207). The table conversion unit is a table used for the process of correcting the image data of each color when the raster image processor 1504 in FIG. 15 generates a bitmap image. For example, when the density of the cyan third patch in the test pattern 1601 of FIG. 16 is measured to be lower than the reference value, the correction table in which the calibration is performed is equal to the reference value corresponding to the cyan third patch. When the density value is input, the content is corrected to a value higher than the reference value. By doing so, the output density characteristics of the printer can be brought close to the reference value in the entire density range, and as a result, an appropriate print output with stable output density characteristics can be maintained.

  According to the above procedure, calibration for maintaining an appropriate output density characteristic of the printer can be performed. To that end, a densitometer for measuring the patch output by the printer as described above is required. .

  However, a densitometer used for such a purpose is generally relatively expensive, and it is not practical from the viewpoint of cost to prepare for each printer, and such a density meter is used only for the purpose of stabilizing the density. There are few users who purchase the total. Even if the user can use the densitometer, various complicated operations must be performed, including the operation of measuring individual patches in order to measure the patches of the printer. The problem is that the labor becomes tremendous.

In order to solve the above problem, as disclosed in Patent Document 2, with the spread of networking in the office environment, it has been proposed to use not only a printer but also a copying apparatus as an image output apparatus of an image processing system. . That is, such a copying apparatus can perform generally known copying processing independently of the network system, and can also print out based on image data processed by a host device or the like. Has been. This makes it possible to easily perform calibration in a networked system by effectively using the function of the copying apparatus. In Patent Document 2, in order to carry out calibration, a test chart output from a printer is read by a copying apparatus, and at the same time, a printer identification symbol printed on the test chart is read to identify a printer that has output the test chart.
JP 2001-094809 A JP 2000-253252 A

  However, according to Patent Document 2, since the output date and time when the test chart is output is not known, there is a possibility that the test chart desired to be used for calibration is wrong. Also, calibration is not always performed immediately after the user outputs the test chart, and there may be a time difference from when the test chart is read for calibration, and the cause of the failure is determined. It becomes difficult to do. Furthermore, in the conventional example, the current test chart image quality deterioration state is poor, and even if there is a possibility of failure, calibration will be performed, but even if calibration is performed, the image quality deterioration state is improved. It is not necessary to inform the user of the failure or to call a service person.

  The present invention is intended to solve this problem. Calibration can be performed without an image reading apparatus, and a test chart that is desired to be used for calibration can be corrected. Image processing system, image processing apparatus, image forming apparatus, image reading apparatus, information terminal apparatus, and image processing method capable of easily confirming the cause of a failure when repairing, etc., and further correcting the failure quickly It is another object of the present invention to provide a computer-readable recording medium storing a program for executing the method.

  In order to solve the above problems, the image processing system of the present invention has a calibration function for correcting image quality fluctuations of an output image. Furthermore, the image processing system of the present invention includes reading means for adding the additional information on the test chart having a predetermined test pattern image by the image forming means and reading the test pattern image and the additional information from the output test chart; The image quality information acquisition means for acquiring the image quality information of the test chart from the test pattern image and the determination means for determining whether to execute the calibration of the image output means based on the additional information and the image quality information are connected via a network. The feature is that it was built. Therefore, it is possible to construct an image processing system that can perform calibration even without an image reading device and can eliminate errors in a test chart desired to be used for calibration based on additional information and image quality information.

  The image quality information is preferably at least one of granularity, sharpness, and gradation, or any one of granularity, sharpness, and gradation.

  Furthermore, since the additional information is the number of sheets used since the last maintenance and the operation time since the last maintenance, it is possible to accurately know the status at the time of output. It is possible to carry out an accurate failure diagnosis by an execution judgment or a service person. Further, since the additional information is date / time information when the image output means outputs the test chart, the use of the wrong test chart can be reduced. Furthermore, since the additional information is an identification number that identifies the image forming means that has output the test chart, the image forming means that has output the test chart can be reliably specified.

  Further, when the image quality information is any one of granularity, sharpness, and gradation, the determination means has a value of the image quality information worse than the reference value and a value of the additional information is smaller than a predetermined lower limit value. In this case, it can be determined whether or not the calibration is performed accurately by determining that the calibration is not performed.

  Further, when the image quality information is at least two of granularity, sharpness, and gradation, the judging means determines that all values of the image quality information are worse than the reference value and the value of the additional information is lower than a predetermined lower limit value. By determining that the calibration is not performed when the number is small, it is possible to determine whether or not to perform the calibration accurately.

  Also, when the image quality information is at least two of granularity, sharpness, and gradation, the judging means has a value that is worse than the reference value even if one of the image quality information is lower, and the value of the additional information is a predetermined lower limit value If it is less than that, it can be determined whether or not the calibration is performed accurately by determining that the calibration is not performed.

  Further, when the image quality information is one of granularity, sharpness, and gradation, the judging means has a value of the image quality information worse than the reference value, and the value of the additional information is larger than a predetermined upper limit value. In this case, by determining that the calibration is not performed, it is possible to determine whether or not the calibration is to be performed accurately and to easily determine that the image forming unit needs to be replaced.

  Further, when the image quality information is at least two of granularity, sharpness, and gradation, the judging means determines that all values of the image quality information are worse than the reference value and the value of the additional information is lower than a predetermined upper limit value. If there are many, it can be determined whether or not the calibration is to be performed accurately by determining that the calibration is not performed, and it can be easily determined that the image forming unit needs to be replaced.

  Furthermore, when the image quality information is at least two of granularity, sharpness, and gradation, the determination means has a value that is worse than the reference value even if one of the image quality information is greater than the predetermined upper limit value. By determining that the calibration is not executed when the number is larger than that, it is possible to determine whether or not the calibration is to be performed accurately and to easily determine that the image forming unit needs to be replaced.

  The image processing system of the present invention also stores additional information on a test chart having a predetermined test pattern image by a state memory that stores information relating to image quality of the test chart output in the past as history information and an image forming unit. Based on the history information, additional information, and image quality information, reading means for reading the test pattern image and additional information from the added and output test chart, image quality information acquisition means for acquiring image quality information of the test chart from the test pattern image, It is characterized in that it is constructed by connecting a determination means for determining whether or not to execute calibration of the image output means through a network. Therefore, since it is determined whether or not the calibration is performed based on the history information related to the image quality, the accuracy of the calibration can be increased.

  Further, the history information is at least one or more past image quality information of granularity, sharpness, and gradation, and date / time information when the image quality information is measured. Judgment can be made.

  Further, the judging means determines the image quality per day from the date information of the additional information read by the reading means and the image quality information acquired by the image quality information acquiring means and the date information and image quality information of the history information read from the state memory. A change amount is obtained, and when this change amount is larger than a predetermined value, it is determined that calibration is not executed. Therefore, the degree of change in bad image quality per day can be verified, and it is determined whether or not calibration is performed based on this degree of change, so that the accuracy of calibration can be increased.

  Further, the determination means includes the date / time information of the additional information read by the reading means and the image quality information acquired by the image quality information acquisition means, and any one of granularity, sharpness, and gradation, and the history read from the state memory. The amount of change in the image quality information acquired by the image quality information acquisition means from the one corresponding to the image quality information acquired by the image quality information acquisition means from the granularity, sharpness, and gradation among the date information and image quality information When this amount of change is larger than a predetermined value, it is determined that calibration is not executed. Therefore, it is possible to determine whether or not to perform calibration more accurately.

  The determination means reads from the state memory at least two or more of granularity, sharpness, and gradation among the date and time information of the additional information read by the reading means and the image quality information acquired by the image quality information acquisition means. The date information and image quality information of the history information acquired from the granularity, sharpness, and gradation by the image quality information acquisition means from at least two corresponding to the image quality information acquired by the image quality information acquisition means. A plurality of change amounts of the image quality information are obtained, and if any one of the change amounts is larger than a predetermined value, it is determined that the calibration is not executed. Therefore, it is possible to determine whether or not to perform calibration more accurately.

  Furthermore, when the determination means determines that the calibration is not performed, it has a failure notification means for notifying that there is a possibility of failure, so that the cause of the failure can be simplified when a serviceman repairs the failure. It can be confirmed and the failure can be corrected sooner. In addition, the failure notification means can visually recognize that there is a possibility of failure by performing a display indicating the failure on the display panel.

  In addition, the failure notifying means notifies the central management device that manages the device that there is a possibility of failure via a communication line, thereby eliminating the trouble of making a serviceman request by the user and improving user support. It becomes.

  Furthermore, an image processing apparatus as another invention performs image processing of an image forming unit having a calibration function for correcting image quality variation of an output image. The image processing apparatus according to the present invention further includes reading means for adding the additional information on the test chart having a predetermined test pattern image by the image forming means, and reading the test pattern image and the additional information from the output test chart; It is characterized by having image quality information acquisition means for acquiring image quality information of a test chart from a test pattern image, and determination means for determining whether or not to perform calibration of the image output means based on the additional information and the image quality information. is there. Therefore, an image processing apparatus that eliminates mistakes in a test chart that is desired to be used for calibration, can easily check the cause of a failure when a serviceman repairs the failure, and can quickly correct the failure. Can be provided.

  An image forming apparatus as another invention is characterized by functioning as the above-described image forming means.

  Furthermore, an image reading apparatus as another invention is characterized in that it functions as the reading means described above. In addition, the image reading apparatus of the present invention is characterized in having functions as the above-described reading means and determination means.

  In addition, an information terminal device as another invention is characterized in that it functions as the determination means described above.

  Furthermore, according to another image processing method of an image forming unit having a calibration function for correcting image quality fluctuation of an output image, the image forming unit places a test chart image having a predetermined test pattern on the test chart. Reads the test pattern image and additional information from the output test chart with the additional information added, acquires the image quality information of the test chart from the test pattern image, and executes the calibration of the image output means based on the additional information and the image quality information Judge whether to do. Therefore, the calibration can be performed without having the image reading apparatus, the error of the test chart desired to be used for calibration can be eliminated by the additional information and the image quality information, and the calibration can be performed with high accuracy.

  As another invention, additional information is added to a test chart having a predetermined test pattern image by the image forming means, and the test pattern image and the additional information are read from the output test chart. A computer-readable program that stores a program for executing by a computer a function for acquiring image quality information of a test chart and a function for determining whether to execute calibration of image output means based on additional information and image quality information It is characterized by possible recording media. Therefore, it is possible to construct an image processing system for general use without changing the existing system.

  According to the image processing system of the present invention, even an image forming apparatus that does not have an image reading apparatus can perform calibration with high accuracy. Further, the output device that has output the test chart can be reliably identified, and the use of the wrong test chart can be reduced by using the output date and time as additional information. Furthermore, since it is possible to accurately know the state at the time of output, it is possible to perform more reliable calibration and failure diagnosis.

  FIG. 1 is a block diagram showing a configuration of an image processing system according to an embodiment of the present invention. As shown in the figure, an image processing system 100 according to this embodiment includes a host computer 101, a scanner 102, and a plurality of units, for example, two color printers 103 and 104, and each unit has a network 121. Are connected to each other. As the network 121, a so-called Ethernet (registered trademark) system is known, and information transmission and data exchange between units connected by a protocol such as TCP / IP using a physical cable such as 10BaseT is used. You can transfer. The host computer 101 includes a display unit (not shown), an operation unit (not shown) such as a keyboard and a mouse, and processing for image output is performed by software of an application or a printer driver. The scanner 102 includes a network interface 105, an image processing unit 106, a scanner unit 107, an image memory 108, a control unit 109, a CPU 110, and a memory 111. The color printers 103 and 104 have network interfaces 112 and 116, raster image processors 113 and 117, status memories 114 and 118, and image forming units 115 and 119, respectively, and each component is connected via an internal bus 120. ing. The scanner 102 outputs an image based on the image data transferred from the host computer 101. At this time, the raster image processors 113 and 117 convert the image data in the PDL format into bitmap data. Further, the scanner 102 also plays a role as a host device as will be described later regarding the calibration of the color printers 103 and 104 connected via the network 121. The image memory 108 in the scanner 102 stores image data sent via the internal bus 120, and the control unit 109 controls the operation of the entire system, which is stored in the memory 111 by the CPU 110. This can be achieved by sending a control signal to the control unit 109 in accordance with the program that is being executed. As will be described later, the CPU 110 also controls the entire system regarding the calibration according to the present embodiment. Including this case, each unit of the scanner 102 exchanges information and commands (commands) and transfers image data with the host computer 101 and the color printers 103 and 104 via the network interface 105. Can do.

  The color printers 103 and 104 have the same functions as each other. The network interface units 114 and 118, the raster image processors 115 and 119, and the image processing executed by the raster image processor for managing the printer status. It includes state memories 116 and 120 for storing conditions and the like, and image forming unit units 117 and 121 using an electrophotographic system. In each printer, illustration of a CPU for controlling the operation, a memory for storing image data, and the like is omitted. These printers 103 and 104 are configured to be able to output a predetermined pattern and update a correction table based on an instruction from the scanner 102 or the like in the calibration of the present embodiment described later.

  Of course, the raster image processors 113 and 117 and the state memories 114 and 118 may be configured in the host computer 101. In addition, the image output method such as a scanner is not limited to the above-described electrophotographic method, and other methods such as an ink jet method may be used. The host computer 101 and the scanner 102 and the color printers 103 and 104 as image output devices exchange information and data through a network 121 via network interfaces 105, 112, and 116 provided respectively.

  Here, the configuration of the scanner 102 in FIG. 1 will be described in detail. The scanner 102 is a digital type using a laser beam, and includes an image processing unit 106, an image memory 108, and a control unit 109. Are connected to each other via an internal bus 120 and to a network 121 via a network interface 105. The image processing unit 106 reads a document image in units of pixels having a predetermined density, and outputs an image signal obtained thereby as a digital signal. The image signal processed by the scanner unit 107 and the image processing unit 106 is sent to the network 121 via the network interface 105. When scanning a normal document image, an image signal read by the scanner unit 107 is sent to the image processing unit 106, and the image processing unit 106 uses known images such as shading correction, sharpness correction, gamma correction, and binarization. Processing is performed and the data is sent to the host computer 101 via the network 121.

  FIG. 2 is a schematic sectional view showing the configuration of the scanner of FIG. In the scanner 200 shown in the figure, a document feeder 201 feeds documents one by one from the last page onto the platen glass 202, and discharges the document on the platen glass 202 after the document reading operation is completed. is there. When the document is conveyed onto the platen glass 202, the lamp 203 is turned on, the scanner unit 204 equipped with the lamp 203 is moved, and the document is exposed and scanned. Reflected light from the original by this scanning is guided to a CCD color image sensor (hereinafter referred to as CCD) 209 by mirrors 205, 206, 207 and a lens 208. The reflected light incident on the CCD 209 is separated into three colors of R, G, and B and is read as a luminance signal for each color. Further, the luminance signal output from the CCD 209 is input to the image processing unit 106 of FIG. 1 as image data of a digital signal by A / D conversion, and known image processing such as shading correction, gradation correction, and binarization is performed. Then, it is transferred onto the network 121 of FIG.

  FIG. 3 is a schematic sectional view showing the configuration of the color printer of FIG. In the color printer 300 shown in the figure, a laser driver 311 drives the laser light emitting unit 301, and laser light corresponding to the image data for each color sent from the host computer 101 in FIG. To emit light. The laser beam is irradiated onto the photosensitive drum 302, and a latent image corresponding to the laser beam is formed on the photosensitive drum 302. Then, a toner as a developer is attached to the latent image portion of the photosensitive drum 302 by the developing unit 303. In FIG. 3, only one developing device is shown for simplification, but toner is prepared for each color of C, M, Y, and K, and four developing devices are provided accordingly. Of course. Further, instead of the above configuration, four sets of photosensitive drums, developing devices, and the like may be provided for each color. The recording paper is fed from either the cassette 304 or the cassette 305 at a timing synchronized with the start of the laser light irradiation described above, and is conveyed to the transfer unit 306. As a result, the developer attached to the photosensitive drum 302 can be transferred to the recording paper. The recording sheet to which the developer has been transferred is conveyed to the fixing unit 307, and the developer is fixed onto the recording sheet by the heat and pressure of the fixing unit 307. The recording paper that has passed through the fixing unit 307 is discharged by a discharge roller 308. If double-sided recording is set, the recording paper is conveyed to the discharge roller 308, and then the rotation direction of the discharge roller 308 is reversed and guided to the refeed conveyance path 310 by the flapper 309. When multiple recording is set, the recording paper is guided to the refeed conveyance path 310 by the flapper 309 so as not to be conveyed to the discharge roller 308. The recording sheet guided to the refeed conveyance path 310 is fed to the transfer unit 306 at the timing described above. As is well known, the latent image and development processing and fixing for each color are realized by repeating the latent image formation and the like four times using the recording paper transport mechanism described above.

  Next, a calibration process or operation procedure that can be performed for the color printer in the image processing system of the present embodiment described above will be described with reference to FIG. 1 and FIG. 4 showing the procedure flow.

  First, the CPU 110 of the scanner 102 in FIG. 1 executes based on a program stored in the memory 111. When it is desired to calibrate the color printer 103 in FIG. 1, when the color printer 103 and the scanner 102 are turned on, this processing procedure is started. First, in order to instruct the predetermined operation panel of the color printer 103 to execute calibration. Is displayed, for example, as shown in FIG. As shown in FIG. 5, the display button can select “test chart output”. When the execution of calibration is instructed by the user via the operation panel, test chart output is started (step S101). In this embodiment, it is assumed that the identification symbol of the color printer 103 is “No. 1” and the identification symbol of the color printer 104 is “No. 2”, which are written in the state memories 114 and 118 in advance. The memory 111 of the scanner 102 in FIG. 1 stores information corresponding to color printers and identification symbols. As the printer identification symbol, the IP address of the printer in the network may be used, or these may be written as a one-dimensional or two-dimensional barcode. Further, in the state memories 114 and 118 of the respective color printers 103 and 104 in FIG. 1, the output state and the like are registered for each output date and time of the test chart as shown in the table of FIG. The test chart is read by the scanner 102 in FIG. 1 (step S102), and information relating to image quality, such as granularity, sharpness, gradation, etc., is measured (step S103), and then the color is transmitted via the network. Information relating to image quality is stored as history information in the status memories 114 and 118 of the printers 103 and 104 (step S104). Here, as the information related to the image quality to be measured, any one or more information of granularity, sharpness, and gradation is used. It should be noted that the history information of the information related to the state of output and the image quality is stored for each output date and time, but of course, an ID number is assigned to each test chart output when the test chart is output, and the output date and time is assigned to each ID number. The history information of the information related to the image quality such as the output state or the like may be registered in the state memory.

  Here, an example of the test pattern output in this embodiment is shown in FIG. A part of the paper on which the test pattern is printed, for example, in the lower part, as additional information, a printer identification number 701 for identifying which color printer the pattern is output, and an output date and time indicating when the test pattern is output 702 is printed. In addition, the output status (humidity, temperature, etc.), usage information (number of used sheets, operating time, etc.) since the previous maintenance of the toner, maintenance work such as maintenance by a service person, are printed. This additional information can be output on the paper together with the gradation pattern by the raster image processor generating the bitmap data based on the identification information written in the status memory of each printer and the output date and time. Become.

  When the test pattern is printed in FIG. 4, the user takes out the test pattern document on which the test pattern has been printed from the printer, and places it on the platen glass of the scanner 102 in FIG. The calibration operation screen shown in FIG. 8 is displayed. The user can instruct the start of calibration by pressing a button for instructing “execute calibration” on the operation screen. If it is determined that reading of the test chart is instructed, reading or the like is executed via the control unit 109 of FIG. First, the color scanner unit is instructed to read the image data of the entire test pattern placed on the platen glass. The color scanner unit performs the reading operation as described above, and sends the read image data to the image memory 108 in FIG. Information related to image quality (granularity, sharpness, gradation, etc.) is measured based on the read image data, and history information related to image quality is obtained from the status memory of the corresponding printer from the identification information of the printer. It is determined whether or not to execute calibration based on the measured result and the acquired result (step S105). For example, it is assumed that granularity is stored as history information as information relating to image quality. In that case, the granularity measurement (the measurement method is described below) is performed from the read image data by the test pattern reading operation. The granularity measurement method will be described later. Further, when the granularity is high, the image quality is poor, and when it is low, the image quality is good. The measurement result is compared with the granularity data stored in the history information. First, based on the printer identification information and output date / time, which is additional information, the printer that output the test chart is identified, and output before the output date / time listed on the test chart from the status memory of the identified printer The granularity result of the test pattern is acquired.

  If it demonstrates along a specific example, it will be determined whether calibration is implemented by seeing the change of the granularity per day. In the case of 0.04 <granularity difference / one day, it is determined that the granularity deterioration is large and it is determined that there is a possibility of failure, that is, it is determined not to perform calibration (step S105; NO). On the other hand, it is assumed that the test chart is output on June 1, 2004. The granularity is measured (granularity = 0.1), and since there is no previous information in the history information, it is determined that the calibration is performed (step S105; YES), and the history information on June 1, 2004 is granular. A degree value of 0.1 is stored. Next, it is assumed that the test chart is output on June 5, 2004. The granularity is measured (granularity = 0.15), the previous history information is acquired (June 1, 2004, granularity 0.1), and the granularity difference / one day is calculated. 0.0125 = granularity difference 0.05 (0.15-0.1) / 4 days (5 days-1 day), which is 0.04 or less, so it is determined that calibration is performed (step S105; YES), a granularity value of 0.15 is stored in the history information of June 5, 2004.

  It is assumed that the test chart is output on June 15, 2004. The granularity is measured (granularity = 0.6), previous history information is acquired (June 5, 2004, granularity 0.15), and the granularity difference / one day is calculated. Then, 0.045 = granularity difference 0.45 (0.6-0.15) / 10 days (15 days-5 days), which is larger than 0.04, so it is determined that there is a possibility of failure. That is, it is determined that the calibration is not performed (step S105; NO). If it is determined not to perform calibration, for example, the maintenance work of the scanner in FIG. 8 is blinked to notify the user of the failure (step S108).

  The present invention is not limited to the above method, and other examples include the above conditions (for example, 0.04 <granularity difference / one day) and a granularity of 0.6 or more when a test chart is output. If it becomes, it may be determined that there is a possibility of failure.

  When it is determined whether or not to perform such calibration, and it is determined that calibration is to be performed, the CPU 110 in FIG. 1 temporarily accumulates in the image memory 108 in FIG. 1 as will be described in detail below. The obtained image data is analyzed to obtain the density value of each patch. Since the density value is used for the measurement of gradation, when the measurement result of the gradation is used for determining whether or not to perform calibration, the density value that has already been measured can be used. A correction table is created based on the obtained density value (step S106), and is registered in the status memory of the designated printer via the network (step S107). For example, the printer identification symbol printed on the test pattern is “No. 1”, the correction table in the state memory 114 of the color printer 103 is updated, and the granularity result measured above is also used as history information in the state memory 114. Remembered.

  As described above, according to the present embodiment, when performing calibration, the user can perform all operations in the scanner except for taking out the pattern original from the printer, and sequentially in the operation unit of the scanner. It is only necessary to perform a designation operation according to the displayed screen, and printer calibration in an image processing system in which a plurality of printers are connected can be easily performed. Further, by describing the output date and time in the additional information, the possibility of using an incorrect test chart can be reduced. Furthermore, it is possible to determine whether or not to perform calibration based on the history information related to image quality, that is, to determine failure, and to increase the accuracy of calibration. Furthermore, since the scanner itself performs the process related to calibration as shown in FIG. 4, the processing load on the host computer can be reduced.

  Although the correction table configured by the scanner 102 in FIG. 1 is sent to the corresponding printer and registered, the correction table can be registered in the host computer 101 in FIG. 1 depending on the system configuration. Of course, it may be. If it is determined that the calibration is not to be performed, the maintenance work of the scanner in FIG. 8 is blinked to notify the user of the failure as described above, and the user makes a serviceman request due to the failure by telephone or the like. The user himself / herself may not be required to make a serviceman request. For example, the scanner 102 of FIG. 1 constructs a communication mechanism in which the scanner 102 is connected to the central management apparatus that has jurisdiction over the data communication apparatus and the communication line, and the central management apparatus installed in each service center. If a terminal device installed at each service base is connected via a communication line, information indicating that calibration is not performed is transmitted to the central management device, and the central management device controls the image output device. By transmitting information to the terminal device installed at the base, the user himself / herself does not need to make a request from the service person, and the user support is improved. Note that a public line network such as a telephone line can be used as the communication line.

  Also, since the output state (humidity and temperature) at the time of output and usage information from the previous maintenance work are printed on the test chart, the service person can easily see the information and print it out. It is also possible to identify the cause of failure from the information.

Here, a method for measuring granularity, sharpness, and gradation will be briefly described.
As a method for measuring granularity, for example, two-dimensional position information of an image to be evaluated and RGB signal information are read from a scanner or the like, a spatial frequency component of the image to be evaluated is obtained, and a frequency obtained by multiplying human visual frequency characteristics is used. There is a method in which integration is performed in the region, and the obtained value is corrected for the average brightness or density of the image, and the obtained value is used as the granularity. The granularity is a value for evaluating roughness, and the smaller the value, the better the image quality.

  As a method for measuring sharpness, for example, a ladder pattern having a different spatial frequency is read from a scanner or the like, and a value obtained by correcting a spatial frequency characteristic generally called MTF with a human visual frequency characteristic is used as the sharpness. . The sharpness is a value for evaluating sharpness, and the larger the value, the clearer the line.

  Further, as a method for measuring gradation characteristics, for example, there is a method of measuring a brightness difference or density difference perceived for an image output at an adjacent gradation level. In general, in a printer or digital image processing system in which input / output gradations are discrete, a relative numerical relationship of an output level to an input level and an input / output curve (γ curve) may be referred to as gradation characteristics. The smaller the tone evaluation value, the better the tone reproducibility.

  In addition to the above-mentioned examples, various methods have been proposed as methods for measuring sharpness, granularity, and gradation characteristics, and methods for deriving them. In addition to the examples given above, various methods have been proposed as measurement physical quantities for obtaining degree and gradation characteristics, depending on whether density is used or brightness is used, and these may be used. In addition to the examples given above, various methods have been proposed for the spatial frequency component derivation method, the correction method based on human visual characteristics, and the correction method for the average characteristic of the image. good.

Next, details of creation of the correction table described above will be described below.
Image data read from the entire surface of the output paper by the color scanner unit of the scanner 102 in FIG. 1 is a bitmap image for each color of R, G, B by color separation, as shown in FIG. It is registered in the image memory 108 of FIG. 9A, 9B, and 9C are diagrams schematically showing these bitmap data. FIG. 9A shows an R plane 901, and FIG. 9B shows a G plane 902. FIG. (C) of FIG. 8 shows the B plane 903, respectively. In these drawings, a white portion represents a region having a larger signal value, that is, a bright (low density) region, and a black portion represents a region having a small signal value, that is, a high concentration. As is apparent from these drawings, the R plane 901 indicates that the high density portion of the cyan and black patches is read as a high density region, the G plane 902 is magenta and black, and the B plane 903 is yellow and black. , Indicates that the respective densities are read as they are. Therefore, in order to measure the density of the cyan patch, it is sufficient to use the data of the R plane 901, the density of the magenta patch using the data of the G plane 902, and the density of the yellow patch using the data of the B plane 903. . For the black patch density, any of R, G, and B planes may be used, but in this embodiment, data of the G plane is used.

  FIG. 10 shows read image data of the R plane, which is the same as the R plane 901 shown in FIG. In FIG. 10, only the rectangle indicating the position of each patch is shown, and the brightness of the patch is omitted. In the following, with reference to FIG. 10, the measurement of the density of the cyan patch will be described as an example. As shown in the figure, the image data is a collection of pixel values arranged in a matrix on the two-dimensional coordinates of x and y, and the position and size of each patch can be designated by the coordinate values of x and y. . Since the x and y coordinates are determined by a gradation pattern output command sent to the printer at the time of pattern printing, the coordinate value is stored in advance in association with the pattern output command. The coordinate value may be read out here.

  First, an image clipping region 1000 (inside the rectangle indicated by diagonal lines) is determined based on the position coordinates of the lowest density patch (tone number 0) from the uppermost patch row of cyan, and an image inside the rectangle is determined. Data S (x, y) is read. Since the data S (x, y) is usually expressed as a digital signal of about 8 bits, it will be described here as an integer value of 0-255. Data S (x, y) is a collection of image data in the image cutout area 1000, and the total number is determined by the number of pixels included in the rectangular area of the image cutout area 1000. If the number of pixels in the x direction in the rectangular area is Nx pixels and the number of pixels in the y direction is Ny pixels, the total number of data S (x, y) is Nx × Ny pixels. Next, an average value Sm of pixel values in the image cutout area 1000 is obtained. This is obtained by the following equation (1).

  Sm = (ΣS (x, y)) / (Nx × Ny) (1)

  Here, Σ represents the sum of the data in the rectangular area of the image cutout area 1000. The obtained average value Sm is expressed as Sc0A because it is the average value of the pixel data of the patch of gradation number 0 in the upper patch row of cyan.

  Next, move to the second patch of cyan. Similarly to the above, the image cutout area 1001 is obtained based on the patch position coordinate information, and the average value Sc1A of the pixel data is obtained by the same procedure. In the same manner, the image cutout areas 1002, 1003,..., 1007 are sequentially advanced to obtain average value data Sc2A, Sc3A,.

  When the above processing is completed, the process moves to the lower patch of cyan, and on the contrary, the image cutout area 1010 is obtained from the rightmost patch, and the average value of the pixel data is obtained. In the lower row, the rightmost end corresponds to the gradation number 0, which is represented as Sc0B. Similarly, in the lower stage, average values are obtained for the image cut-out areas 1011, 1012,..., 1017, and are referred to as Sc 1, Sc 2 B,. Here, the image cutout area 1000 and the image cutout area 1010, the image cutout area 1001 and the image cutout area 1011,..., And the image cutout area 1007 and the image cutout area 1017 are patches that reproduce the same gradation level. Originally, the average value data obtained should be equal if there is no density fluctuation due to the output position of the printer and no fluctuation in the reading value due to the reading position of the scanner section. That is, Sc0A = Sc0B, Sc1A = Sc1B,..., Sc7A = Sc7B, but in reality, they are not necessarily equal due to various fluctuation factors. Therefore, in the present embodiment, in a situation where Sc0A = Sc0B, Sc1A = Sc1B,..., Sc7A = Sc7B does not necessarily hold, processing is performed assuming that the average value of both is a true patch reading value. . That is, assuming that Sc0, Sc1,..., Sc7 are true patch data, Sc0 = (Sc0A + Sc0B) / 2, Sc1 = (Sc1A + Sc1B) / 2,..., Sc7 = (Sc7A + Sc7B) / 2. As described above, when the average image signal of each patch is obtained, these are converted into density values. The image data read by the scanner unit of the scanner is usually a so-called luminance signal proportional to the reflectance of the document, and an appropriate logarithmic conversion process is performed to convert this into a density value. The following formula (2) is used as an example of a conversion formula for expressing the density value D as an 8-bit integer value.

  D = −255 × log 10 (S / 255) /2.0 (2)

  This equation (2) is an equation for converting the luminance signal S so that D = 255 when the document density is 2.0. When D is 255 or more, the luminance signal S is limited to 255.

  Using this equation (2), Sc0, Sc1,..., Sc7 obtained above are converted into density values Dc0, Dc1,. That is, Dc0 = −255 × log10 (Sc0 / 255) /2.0, Dc1 = −255 × log10 (Sc1 / 255) /2.0,..., Dc7 = −255 × log10 (Sc7 / 255) / 2.0. The density values for magenta, yellow, and black, which are patches of other colors, can be obtained by a similar procedure. The density values thus obtained are represented as Dm0 to Dm7, Dy0 to Dy7, and Dk0 to Dk7, respectively.

  Of course, the conversion to the density value described above is not limited, and other conversion formulas may be used. Alternatively, the relationship between the luminance signal value and the density value may be measured in advance and used as a lookup table, and density conversion may be performed using this table.

  FIG. 11 is a characteristic diagram in which the density values Dc0 to Dc7 of the cyan patches obtained as described above are plotted corresponding to the tone numbers of the patches. In the figure, the horizontal axis represents the gradation number and the printer input signal value, and the vertical axis represents the density value. In the figure, the points indicated by ◯ indicate the measured density values of each patch, and a straight line 1101 indicated by a thin line connects these measured values. Here, the density value that should be originally measured for each patch indicated by each gradation number from 0 to 7 corresponds to the signal value input to the printer that is the image forming unit, from 0 to 255 represented by the 8-bit signal. This corresponds to eight signal values sampled at equal intervals. That is, in an ordinary printer, 8-bit signals are input for C, M, Y, and K, respectively, and binarization processing using a known dither processing or error diffusion method or the electrophotographic photosensitive member is exposed based on this signal value. The laser emission time modulation process is performed, dots are formed on the paper, and a gradation image is printed out. In the present embodiment, since the patches 0 to 7 described above are output based on signal values obtained by dividing 8-bit signals of 0 to 255 at equal intervals, the gradation number 0 = input signal on the horizontal axis of FIG. Value 0, gradation number 1 = input signal value 36, gradation number 2 = input signal value 73, gradation number 3 = input signal value 109, gradation number 4 = input signal value 146, gradation number 5 = input signal There is a correspondence relationship of value 182, gradation number 6 = input signal value 219, gradation number 7 = input signal value 255. In FIG. 11, a straight line 1102 indicated by a bold line shows an example of an ideal reference density characteristic that should be taken by the measured density value of the patch with respect to the input signal value in the printer. That is, the printer desirably has a linear output density characteristic proportional to the input signal value. However, the color space of the input signal value of the printer and the output color space of the printer are generally not in a linear correspondence relationship. For this reason, the input signal value is usually calculated using a lookup table and an interpolation operation. Correction is being performed. However, the look-up table described above may be relatively inappropriate due to factors such as changes in the printer over time and environmental fluctuations, and as a result, output as indicated by a straight line 1101 indicated by a thin line in FIG. Concentration characteristics. The calibration is performed in order to make such output density characteristics as shown by a straight line 1102 indicated by a bold line, and specifically, is performed by changing the contents of the lookup table.

  In the present embodiment, the lookup table described above is used when the raster image processor in the printer rasterizes the PDL command and generates a bitmap image that is each of the input signal values of C, M, Y, and K. For this lookup table, a correction table obtained based on the above-mentioned density measurement value is created in the scanner, and this is transferred to the printer and processed as the contents of the lookup table. That is, the contents of the look-up table may be a table having the reverse characteristic of the straight line 1101 shown by the thin line in FIG. 11, and the CPU 110 of the scanner 102 in FIG. A conversion table having characteristics is calculated for each of C, M, Y, and K, transferred to the color printers 103 and 104 in FIG. 1 to be calibrated, and stored in the state memories 114 and 118 according to the contents thereof. Update the lookup table.

  FIG. 12 is a diagram schematically showing the contents of the lookup table updated by calibration. In the figure, a straight line 1201 indicates the relationship between the density value of the bitmap data with respect to the density value of the data obtained by rasterizing the PDL command. The reverse characteristic, that is, the straight line 1101 indicated by the thin line in FIG. It is shown as a symmetrical curve with respect to the straight line 1102 made. In normal printing, the updated look-up table is used to convert the rasterized signal value (here, C signal) into a signal value (C ′ signal) for writing into bitmap data.

  FIG. 13 is a block diagram showing a detailed configuration of the raster image processor of FIG. In this figure, a PDL command sent from a host computer or scanner via a network interface is expanded into a C, M, Y, K bitmap image by a rasterizer 1301 and stored in an image memory 1303. The tone correction table (the above-mentioned lookup table) 1302 corrects the image. In the above description, the gradation correction table created by the CPU 110 of the scanner 102 in FIG. 1 is temporarily stored in the state memories 114 and 118 of the color printers 103 and 104 in FIG. When the rasterization process is performed, the correction table in the state memory is read and set in the time correction table 1302.

  In the above-described configuration, when the image forming units 115 and 119 of the color printers 103 and 104 in FIG. 1 represent an image with binary values of dot on and off, for example, as in the ink jet method. As described above, the C ′ signal is written in the state memory 1303 of FIG. 13 after further known pseudo-halftone processing such as dither processing. In the example shown in FIG. 13, the gradation correction table (lookup table) 1302 is placed at the front stage of the image memory 1303, but is arranged at the rear stage of the image memory 1303 and simultaneously sends data to the image forming unit. Of course, a configuration in which gradation correction is performed may be used. Furthermore, in this embodiment, by having one scanner that can perform calibration, other printers (copiers) can also perform calibration using the scanner. Further, when outputting the test chart, the date and time of output are printed in addition to the identification symbol of the color printer output on the test chart, so that the user can be prevented from making a mistake in the test chart. Also, by looking at the state of granularity measured previously, it is unlikely that image quality will be improved even if calibration is performed, and a case where there is a possibility of failure can be easily found. That is, calibration and failure diagnosis can be performed simultaneously, which improves user support.

  Next, as described above, it is determined whether or not the calibration is performed by using the granularity as the history information. By using three of the granularity, the sharpness, and the gradation as the history information, it is determined. It can also be determined whether or not to perform calibration. The processing is performed by the CPU 110 in FIG. The rate of change per day for each of granularity, sharpness, and gradation is calculated, a threshold is provided for each, and it is determined whether or not to perform calibration. For example, if 0.04 <granularity difference / 1 day or -0.006> sharpness difference / 1 day or 0.006 <gradation difference / 1 day, it is determined that there is a possibility of failure.

  A description will be given along a specific example. First, it is assumed that a test chart is output on June 1, 2004. Measure granularity, sharpness, and gradation (results: granularity = 0.1, sharpness = 0.4, gradation = 0.9), and there is no previous information in the history information, so calibration In the history information on June 1, 2004, the granularity 0.1, the sharpness 0.4, and the gradation 0.9 are stored. Next, it is assumed that the test chart is output on June 5, 2004. Measure granularity (results: granularity = 0.15, sharpness = 0.4, gradation = 0.91), and obtain previous history information (June 1, 2004, granularity 0.1 Sharpness 0.4, gradation 0.9), granularity difference / 1 day, sharpness difference / 1 day, gradation difference / 1 day. 0.0125 = granularity difference 0.05 (0.15-0.1) / 4 days (5 days-1 day), 0 = sharpness difference 0 (0.4-0.4) / 4 days (5 Day-1), 0.0025 = gradation difference 0.01 (0.91-0.9) / 4 days (5 days-1 day), and granularity, sharpness, and gradation are all 0.04. Therefore, it is determined that the calibration is performed, and the granularity 0.15, the sharpness 0.4, and the gradation 0.91 are stored in the history information on June 5, 2004. Further, it is assumed that a test chart is output on June 15, 2004. The granularity is measured (results: granularity = 0.5, sharpness = 0.35, gradation = 0.98), and previous history information is acquired (June 5, 2004, granularity 0.15) Sharpness 0.4, gradation 0.91), and difference in granularity / one day is calculated. 0.035 = granularity difference 0.35 (= 0.5-0.15) / 10 days (= 15 days-5 days), -0.005 = sharpness difference-0.05 (= 0.35- 0.4) / 10 days (= 15 days-5 days), 0.007 = gradation difference 0.07 (0.98-0.91) / 10 days (15 days-5 days) That is, it is determined that the calibration is not performed.

  04> granularity difference / 1 day (= 0.035), -0.006 <sharpness difference / 1 day (= -0.005), 0.006 <gradation difference / 1 day (= 0.007) And the condition of gradation (0.04 <granularity difference / one day or -0.006> sharpness difference / one day or 0.006 <gradation difference / one day) That is, it is determined that there is a possibility that the calibration is not performed.

  As another example, the determination may be made by substituting three of granularity, sharpness, and gradation in an expression for evaluating the poor image quality. For example, it is assumed that the following equation (3) is used as an equation for evaluating the poor image quality. The value on the left side is assumed to be a value of image quality of an ideal image with a value of 0, and the larger the value, the worse the image quality.

  (Poor image quality) = P1 / (Sharpness) + P2 × (Granularity × Sharpness × Gradation) −P3 (3)

  The measured granularity, sharpness, and gradation, and the granularity, sharpness, and gradation obtained from the previous history information are substituted into the above equation (3), and the values of poor image quality are obtained. Then, the rate of change in the poor image quality per day is obtained to determine whether or not to perform calibration. For example, when 0.8 <difference in image quality / 1 day, it is determined that there is a possibility of failure.

  In any of the above examples, the determination is performed by calculating the change rate per day of the information relating to the image quality. However, the change rate per time may be used as a matter of course. Further, as described above, the history information regarding the image quality is acquired from the test pattern data and the additional information printed on the test chart, and it is determined whether or not the calibration is performed based on the history information. Whether or not calibration is to be performed may be determined based on the number of sheets used since the previous maintenance work, the operating time, and the output state (environmental state where the output machine is installed: temperature, humidity). For example, it is determined whether or not calibration is performed based on the test pattern data and the number of used sheets from the previous replacement time. For example, when the measured value (granularity) of the test pattern data is 0.5 and the number of used sheets from the previous maintenance work period is <500 sheets, or the number of used sheets from the previous maintenance work period is> 2000 sheets, It is determined that calibration is not performed. This can be determined that the number of used sheets from the previous maintenance work period is small (for example, the number of used sheets from the previous maintenance work period <500 sheets), but the image quality is poor, that is, there is a possibility of failure. Further, since the number of used sheets from the previous maintenance work period is large (for example, the number of used sheets from the previous maintenance work period> 2000), it can be determined that the image quality is poor, that is, the maintenance work is necessary. This is because even if calibration is performed without performing maintenance work, the image quality improvement effect by calibration cannot be expected so much.

  Therefore, when the measured value of the test pattern data (granularity)> 0.5 and the number of used sheets from the previous maintenance work time <500, the user is displayed by displaying “failure” on the display screen on the reader. To tell. On the other hand, when the measured value of the test pattern data (granularity)> 0.5 and the number of used sheets from the previous maintenance work time> 2000, for example, “Maintenance work time” is displayed on the display screen on the reading device. To tell the user. In addition, for example, selection buttons such as “maintenance work” and “continue calibration” may be provided on the operation screen on the reading device, and the user may select them.

  A description will be given along a specific example. First, test pattern data is measured (for example, granularity = 0.6). On the other hand, the reading device reads the number of used sheets (for example, 1000 sheets) from the previous maintenance work time added to the additional information. Next, when the measured value (granularity) of the test pattern data> 0.5, and the number of used sheets from the previous maintenance work period <500 sheets, or the number of used sheets from the previous maintenance work period> 2000 sheets. To see. Measured value of test pattern data (granularity 0.6)> 0.5, number of used sheets from previous maintenance work (1000 sheets) <2000 sheets, or number of used sheets from previous maintenance work (1000 sheets)> Since it is 500 sheets, it is determined that calibration is performed.

  Then, test pattern data is measured (for example, granularity = 0.6). On the other hand, the reading device reads the number of used sheets (for example, 300 sheets) from the previous maintenance work time added to the additional information. Next, when the measured value (granularity) of the test pattern data> 0.5, and the number of used sheets from the previous maintenance work period <500 sheets, or the number of used sheets from the previous maintenance work period> 2000 sheets. To see. Test pattern data measured value (granularity 0.6)> 0.5, number of used sheets from previous maintenance work (300 sheets) <2000 sheets, or number of used sheets from previous maintenance work (300 sheets) < Since it is 500 sheets, it is determined that calibration is not performed. Since the measured value of the test pattern data (granularity 0.6)> 0.5 and the number of sheets used (300 sheets) <500 sheets from the previous maintenance work time, this is Even though the number of sheets used is small, it can be determined that the image quality is bad, and it is determined that there is a failure. Then, “failure” is displayed on the display screen on the reading device to inform the user. Note that additional information such as the number of sheets used since the previous maintenance work, operating time, and output status (environmental status where the output machine is installed: temperature and humidity) are stored in the printer status memory. It is also possible to read it out.

  On the other hand, as another example, it may be determined whether or not calibration is performed based on the measurement value of the test pattern data and the state of the output machine (environmental state where the output machine is installed: temperature, humidity). This is because the environmental condition of the place where the output device is installed is bad (for example, the temperature is too high or too low) and the image quality is bad, the environmental condition of the place where the output device is installed is bad. Even if the calibration is performed when the environmental condition is bad, it can be determined that the image quality improvement by the calibration cannot be expected so much, and the calibration is not performed. In addition, when the environmental condition of the place where the output device is installed is good and the image quality is poor, it can be determined that there is a malfunction. Do not do.

  Next, FIG. 14 is a block diagram showing the configuration of a specific apparatus for starting a program for executing the image processing method of the present invention. That is, this figure shows hardware constructed from a microprocessor or the like that executes software according to the image processing method in the above embodiment. In the figure, the image processing system includes an interface (hereinafter abbreviated as I / F) 1401, a CPU 1402, a ROM 1403, a RAM 1404, a display device 1405, a hard disk 1406, a keyboard 1407, and a CD-ROM drive 1408. A general-purpose processing apparatus is prepared, and a readable recording medium 1409 such as a CD-ROM stores a program for executing the image processing method of the present invention. Further, a control signal is input from an external device via the I / F 1401, and an instruction from the operator or the program of the present invention is automatically activated by the keyboard 1407. The CPU 1402 performs control processing associated with the above-described image processing method according to the program, stores the processing result in a storage device such as the RAM 1404 and the hard disk 1406, and outputs it to the display device 1405 or the like as necessary. As described above, by using the recording medium recorded with the program for executing the image processing method of the present invention, an image processing system can be constructed universally without changing the existing system.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and substitutions are possible as long as they are described within the scope of the claims.

1 is a block diagram showing a configuration of an image processing system according to an embodiment of the present invention. It is a schematic sectional drawing which shows the structure of the scanner of FIG. It is a schematic sectional drawing which shows the structure of the color printer of FIG. It is a flowchart which shows the process of the calibration in the image processing system of the example of this Embodiment. It is a figure which shows an example of the instruction | indication display of calibration execution. It is a figure which shows an example of the memory table in the state memory of FIG. It is a figure which shows an example of the test pattern output in this Example. It is a figure which shows an example of a calibration operation screen. It is a figure which shows the bitmap image for every color by color separation. It is a figure which shows the read image data of R plane. FIG. 6 is a characteristic diagram in which density values of cyan patches are plotted in correspondence with patch gradation numbers. It is a figure which shows typically the content of the look-up table updated by calibration. FIG. 2 is a block diagram illustrating a detailed configuration of the raster image processor of FIG. 1. It is a block diagram which shows the structure of the specific apparatus for starting the program which performs the image processing method of this invention. It is a block diagram which shows the structure of the conventional image processing system. It is a figure which shows an example of the test pattern which consists of the conventional predetermined patch. It is a flowchart which shows the process of the conventional calibration.

Explanation of symbols

100; Image processing system 101; Host computer
102; Scanner, 103, 104; Color printer,
105, 112, 116; network interface,
106; Image processing unit 107; Scanner unit 108; Image memory
109; control unit, 110; CPU, 111; memory,
113, 117; raster image processor;
114, 118; status memory; 115, 119; image forming unit;
120 internal bus, 121; network,
701: Printer identification number, 702: Output date and time.

Claims (29)

In an image processing system of an image forming unit having a calibration function for correcting image quality variation of an output image,
Additional information is added to the test chart having a predetermined test pattern image by the image forming means, and reading means for reading the test pattern image and the additional information from the output test chart;
Image quality information acquisition means for acquiring image quality information of the test chart from the test pattern image;
An image processing system comprising: a determination unit configured to determine whether to execute calibration of the image output unit based on the additional information and the image quality information, connected by a network.   The image processing system according to claim 1, wherein the image quality information is at least one of granularity, sharpness, and gradation.   The image processing system according to claim 1, wherein the image quality information is one of granularity, sharpness, and gradation.   The image processing system according to claim 1, wherein the additional information is the number of sheets used since the previous maintenance.   The image processing system according to claim 1, wherein the additional information is an operation time from a previous maintenance.   The image processing system according to claim 1, wherein the additional information is date information when the image forming unit outputs the test chart.   The image processing system according to claim 1, wherein the additional information is an identification number that identifies the image forming unit that has output the test chart.   When the image quality information is any one of granularity, sharpness, and gradation, the determination means determines that the value of the image quality information is worse than a reference value and the value of the additional information is a predetermined lower limit value. The image processing system according to claim 1, wherein the image processing system determines that the calibration is not executed when the number is smaller.   When the image quality information is at least two of granularity, sharpness, and gradation, the determination means determines that all values of the image quality information are worse than a reference value, and the value of the additional information is a predetermined lower limit. The image processing system according to claim 1, wherein when it is less than the value, it is determined that the calibration is not executed.   When the image quality information is at least two of granularity, sharpness, and gradation, the determination means has a value that is worse than a reference value for at least one of the image quality information, and the value of the additional information is predetermined. The image processing system according to any one of claims 1, 2, 4, and 5, wherein it is determined that the calibration is not executed when the lower limit value is smaller.   When the image quality information is any one of granularity, sharpness, and gradation, the determination means has a value of the image quality information worse than a reference value, and the value of the additional information is a predetermined upper limit value. The image processing system according to claim 1, wherein the image processing system determines that the calibration is not executed when the number is larger.   When the image quality information is at least two of granularity, sharpness, and gradation, the determination means determines that all values of the image quality information are worse than a reference value, and the value of the additional information is a predetermined upper limit. The image processing system according to claim 1, wherein the image processing system determines that the calibration is not executed when the number is larger than the value.   When the image quality information is at least two of granularity, sharpness, and gradation, the determination means has a value that is worse than a reference value for at least one of the image quality information, and the value of the additional information is predetermined. The image processing system according to any one of claims 1, 2, 4, and 5, wherein it is determined that calibration is not executed when the upper limit is exceeded. In an image processing system of an image forming unit having a calibration function for correcting image quality variation of an output image,
A state memory for storing information related to image quality of test charts output in the past as history information;
Additional information is added to the test chart having a predetermined test pattern image by the image forming means, and reading means for reading the test pattern image and the additional information from the output test chart;
Image quality information acquisition means for acquiring image quality information of the test chart from the test pattern image;
An image processing system comprising: a determination unit configured to determine whether or not to execute calibration of the image output unit based on the history information, the additional information, and the image quality information. .   The image processing system according to claim 14, wherein the history information is at least one past image quality information of granularity, sharpness, and gradation and date / time information when the image quality information is measured.   The image processing system according to claim 14, wherein the additional information is date information when the image output unit outputs the test chart.   The determination means includes the date and time information of the additional information read by the reading means and the image quality information acquired by the image quality information acquisition means, and the date and time information and image quality information of the history information read from the state memory. The image processing system according to any one of claims 14 to 16, wherein an amount of change in image quality per day is obtained, and it is determined that calibration is not executed when the amount of change is greater than a predetermined value.   The determination means includes any one of granularity, sharpness, and gradation among the date and time information of the additional information read by the reading means and the image quality information acquired by the image quality information acquisition means, and the state Among the date information and the image quality information of the history information read from the memory, the image quality is obtained from one corresponding to the image quality information acquired by the image quality information acquisition means from granularity, sharpness, and gradation. The image processing system according to any one of claims 14 to 16, wherein a change amount of the image quality information acquired by the information acquisition unit is obtained, and when the change amount is larger than a predetermined value, it is determined that the calibration is not executed.   The determination unit includes at least two or more of granularity, sharpness, and gradation among the date and time information of the additional information read by the reading unit and the image quality information acquired by the image quality information acquisition unit, Among the date information and the image quality information of the history information read from the state memory, at least two or more corresponding to the image quality information acquired by the image quality information acquisition means from granularity, sharpness, and gradation From the above, a plurality of change amounts of the image quality information acquired by the image quality information acquisition unit are obtained, and if any one of the plurality of change amounts is larger than a predetermined value, it is determined that the calibration is not executed. Item 17. The image processing system according to any one of Items 14 to 16.   The image processing system according to claim 1, further comprising a failure notification unit that notifies that there is a possibility of a failure when the determination unit determines not to perform calibration.   21. The image processing system according to claim 20, wherein the failure notification unit notifies that there is a possibility of failure by displaying a display indicating a failure on the display panel.   21. The image processing system according to claim 20, wherein the failure notification means notifies the central management apparatus that has jurisdiction over a device that a failure is possible via a communication line. In an image processing apparatus of an image forming unit having a calibration function for correcting image quality variation of an output image,
Additional information is added to the test chart having a predetermined test pattern image by the image forming means, and reading means for reading the test pattern image and the additional information from the output test chart;
Image quality information acquisition means for acquiring image quality information of the test chart from the test pattern image;
An image processing apparatus comprising: a determination unit that determines whether to perform calibration of the image output unit based on the additional information and the image quality information.   An image forming apparatus that functions as the image forming unit according to claim 1.   An image reading apparatus that functions as the reading unit according to claim 1.   24. An image reading apparatus having a function as a reading unit and a determination unit according to claim 1.   An information terminal device that functions as the determination means according to claim 1. In an image processing method of an image forming unit having a calibration function for correcting image quality variation of an output image,
Additional information is added onto the test chart having a predetermined test pattern image by the image forming means, and the test pattern image and the additional information are read from the output test chart, and the image quality of the test chart is read from the test pattern image. An image processing method comprising: acquiring information, and determining whether to execute calibration of the image output unit based on the additional information and the image quality information. In a recording medium storing a program for executing an image processing method of an image forming unit having a calibration function for correcting image quality variation of an output image by a computer,
Additional information is added to the test chart having a predetermined test pattern image by the image forming means, and a function of reading the test pattern image and the additional information from the output test chart, and the test chart from the test pattern image A computer-readable program storing a program for executing a function for acquiring image quality information and a function for determining whether to execute calibration of the image output means based on the additional information and the image quality information recoding media.

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