JP5919788B2 - Image forming apparatus, printing system, and image adjustment method - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on transfer paper, and more particularly to an image forming apparatus that can adjust image quality.

  An image forming apparatus such as a printer, a copier, a facsimile machine, or a multifunction machine equipped with two or more of these functions is equipped with an image forming function for transferring an image onto a transfer sheet as a sheet type medium. Image forming devices initially spread to general offices, but in recent years, offset printing machines have been developed to take advantage of small lot compatibility and variable printing (printing variable data on flyers, direct mail, etc.). It has begun to spread in the mainstream production market (commercial printing market and in-house printing market).

  The image forming apparatus for production printing is the same electrophotographic system as the image forming apparatus for offices, but often prints on a large amount of transfer paper, and the printed matter becomes a product, so the image quality is low. Often more important.

  In addition, in order to guarantee the image quality of the printed matter output from the image forming apparatus, the process of inspecting whether there is an abnormal image generated on the printed matter or image quality deterioration is an important step in the production printing work process. It has been.

  However, as described above, since production printing is performed on a large amount of transfer paper, manual inspection of printed matter has been a great effort.

  For this reason, there is a system that automatically inspects a printed matter by connecting a printed matter inspection device that optically reads the printed matter and compares it with an original image at an output portion of the printed matter of the image forming apparatus (for example, Patent Document 1). reference.). If there is an abnormality in the print quality of the printed material as a result of the comparison, the printed material (hereinafter referred to as a defective printed material) is labeled by some means so that it will not be mixed into a normal printed material (hereinafter referred to as a normal printed material). Discharging process is performed.

  After that, the same print image is printed again to complement the output print product labeled as a defective print product. At that time, the original image is compared with the read image of the defective print product, and the color of the original image is changed. A method of adding such correction is already known.

  However, the conventional method of adding color correction or the like to a document image has a problem that the print quality is affected by the characteristics of a specific brand of transfer paper. For example, when white spots (toner is applied), dirt (a lot of toner adheres), or striped noise occurs on the output image on the transfer paper, every time the transfer paper of the same brand is used. The possibility that a defective printed matter is output is increased.

  However, if the original image is corrected, there is a disadvantage that the quality may be lowered when another brand of transfer paper is used. Such inconvenience is considered to occur because the conventional technology does not correct the image forming conditions of the image forming apparatus.

  In this regard, an image forming apparatus that measures the characteristics of transfer paper and controls the image forming conditions during image formation based on the characteristics of the transfer paper is conceivable (see, for example, Patent Document 2). In Patent Document 2, a test print is performed on a target transfer paper, and the characteristics of the transfer paper are measured.

  However, the measurement of characteristics by test printing has a problem that even if it is effective for single printing, it is not always effective for production printing for forming an image on a large amount of transfer paper. First, when the image forming apparatus is continuously printing, the environment in the apparatus such as temperature and humidity changes with time, and the characteristics measured by the test print may not be suitable. If image formation is performed based on incompatible characteristics, the printed matter printed during that time does not become a product, and the user may waste a large amount of transfer paper and time.

  In addition, there are various types of manuscript data such as a character main body, a photograph, and a color image, but there is no guarantee that a variety of manuscript data can be handled by a test print performed before starting printing. In production printing, since a large number of copies of document data of a plurality of pages are printed, various document data are often printed. Therefore, in the method of Cited Document 2, characteristics measured by a test print of a certain manuscript page are not always effective for image formation of another manuscript page, and depending on the page, reprinting may be required. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that is less susceptible to environmental fluctuations and variations in document data when forming images on various transfer paper brands.

The present invention relates to an image forming apparatus for forming an image on transfer paper, information receiving means for receiving input of transfer paper identification information, original image data acquiring means for acquiring original image data of the image, and the information receiving An image forming means for applying an image forming process control value associated with the transfer paper identification information received by the means to the image forming process to form an image of the original image data on the transfer paper, and forming on the transfer paper Output image data generating means for optically reading the generated image and generating output image data, and for each page of output image data, the original image data and the output image data are compared, and an image quality abnormality of the output image data is detected. When a printed matter inspection means to detect and an image quality abnormality in the output image data is detected, a correction value for the control value that reduces the image quality abnormality is created based on the content and degree of the image quality abnormality. Wherein a correction value generating means for storing in the storage means in association with the transfer sheet identification information, said transfer sheet identification information likely to form at transfer sheet to the image quality type of abnormality is correlated obtained quality abnormality table, a, When the correction value is associated with the transfer sheet identification information received by the information receiving unit, the image forming unit applies the control value corrected by the correction value to the image forming process to transfer paper The printed image inspection means divides the document image data and the output image data into a plurality of regions of the same number and shape, and compares only a part of the plurality of regions. Te, the output is to detect the quality of the image data abnormality at the quality abnormality table, the information receiving means the quality abnormality other image associated with the said transfer sheet identification information accepted Than the abnormality preferentially detected, further, comparing said area so as to slightly the entire region of the output image data for each predetermined number of the output image data, characterized in that.

  When an image is formed on various transfer paper brands, it is possible to provide an image forming apparatus that is not easily affected by environmental fluctuations and document data diversity.

1 is an example of a diagram illustrating an outline of an image forming apparatus. 1 is a schematic configuration diagram of an image forming apparatus. It is an example of the figure explaining a defective printed matter. 2 is an example of a hardware configuration diagram of a controller of the image forming apparatus. FIG. It is an example of the schematic block diagram of an image inspection apparatus. 1 is an example of a functional block diagram of a printing system. FIG. 6 is an example of a flowchart for explaining a procedure in which an image quality comparison / determination unit compares output image data and document image data. It is an example of the figure explaining determination of the amount of position shift. It is a figure which shows an example of the correspondence of a transfer paper brand and the abnormal content of a detection target. FIG. 4 is an example of a diagram illustrating the division of regions of document image data and output image data. It is a figure which shows an example of a setting data group. It is an example of the figure explaining an image quality correction data group. It is a figure which shows an example of the image quality correction data group creation table for an image quality correction data group creation / transmission part to produce an image quality correction data group. FIG. 10 is a flowchart illustrating an example of an operation procedure in which the printing system performs printing using the image quality correction data group (part 1). FIG. 10 is a flowchart illustrating an example of an operation procedure in which the printing system executes printing using the image quality correction data group (part 2). FIG. 3 is an example of a diagram schematically illustrating a setting data group and an image quality correction data group. It is an example of the hardware block diagram of a server. It is an example of the functional block diagram of a server. It is a figure which shows an example of the collection data which a server collects. It is a figure showing an example of the image quality correction data group classified by transfer paper. FIG. 10 is an example of a flowchart illustrating a procedure for a server to identify an image forming apparatus having an abnormality sign. (Example 4) which is an example of the functional block diagram of a server. It is an example of the flowchart figure which shows the operation | movement procedure of a printing system.

FIG. 1 is an example of a diagram illustrating an outline of the image forming apparatus according to the present exemplary embodiment.
First, the image forming apparatus of the present embodiment stores image forming conditions set in advance for each brand of transfer paper. The image forming apparatus is characterized in that based on the comparison result between the original image and the read image of the defective printed material, the stored image forming conditions are corrected so as to suppress abnormal images and quality degradation. Yes.

  First, the server 200 stores a set data group obtained by the professional facility evaluating the performance of the transfer paper by various methods. The image forming apparatus 100 can download a set of transfer paper setting data used by the user from the server 200, and can perform image formation by adjusting the image forming conditions of the engine 101. Therefore, many users can print according to the characteristics of the transfer paper by using this set data group.

  On the other hand, an image inspection apparatus 103 is disposed on the downstream side of the engine 101. The image inspection apparatus 103 compares image data (hereinafter referred to as output image data) obtained by optically reading an output product of the engine 101 with an apparatus such as a scanner and original image data received from the engine 101. As a result, whether the image quality is good or bad is determined, and if the image satisfies the prescribed image quality, the output is directly discharged to the post-processing device.

  There are various methods for the image forming apparatus 100 to acquire the document image data. For example, a method in which a PC (Personal Computer) transmits document image data to the image forming apparatus 100, a method in which the image forming apparatus 100 reads a document and generates document image data, and a document image data stored in an external storage medium is read. There are methods.

  If the image does not satisfy the prescribed image quality, the image inspection apparatus 103 labels the output product as a defective printed material and then discharges it to the post-processing device 104. Then, the user is inquired through the operation unit 102 whether or not to recover the defective printed matter.

  When the user recovers the defective printed matter, the image inspection apparatus 103 can correct the image forming conditions with respect to the engine 101, thereby improving the print quality during the recovery image formation. Hereinafter, the correction data for the setting data group is referred to as an image quality correction data group.

  Therefore, the user of the image forming apparatus 100 can use the setting data group, and if the setting data group cannot satisfy the predetermined image quality, it can print with correction so as to suppress the image quality problem.

  The specialized facility may be a facility that evaluates the performance of transfer paper operated by a specific manufacturer, and does not need to be a standard organization or a public organization. In addition, the user has a meaning of a user as a corporation of the image forming apparatus 100 and a user as a natural person. In the present embodiment, the former is called a user and the latter is called an operator. However, even if it is not strictly distinguished, the user may generically refer to it if it makes sense.

[Configuration example]
FIG. 2 is a schematic configuration diagram of the image forming apparatus 100. An electrophotographic printer will be described with reference to FIG. A copier, a FAX apparatus, a scanner apparatus, or an MFP (Multifunction Peripheral) equipped with this printer is the image forming apparatus 100 of this embodiment.

  A basic configuration of the image forming apparatus 100 will be described. Other configurations such as a sheet feeding unit are omitted.

  The printer generates toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). The printer has four photosensitive drums 11y, 11m, 11c, and 11k, and forms toner images of each color on each photosensitive drum. There are image forming units 1y, 1m, 1c and 1k around the photosensitive drum.

  The image forming units 1y, 1m, 1c, and 1k include drum chargers 12y, 12m, 12c, and 12k, exposure devices 13y, 13m, 13c, and 13k, developing devices 14y, 14m, 14c, and 14k, and transfer devices 15y, 15m, and 15c. , 15k and drum cleaning devices 16y, 16m, 16c, 16k, respectively.

  In the image forming units 1y to 1k, for example, toner images of different colors are formed in which 1y is yellow, 1m is magenta, 1c is cyan, and 1k is black. The transfer belt 21 superimposes these toner images. Contact rollers 22y, 22m, 22c, and 22k are provided to contact the transfer belt 21 and the photosensitive drums 11y, 11m, 11c, and 11k when the toner image is transferred.

  A belt driving roller 23 and a belt cleaning device 24 are disposed around the transfer belt 21. Further, a secondary transfer device 31 is provided at a position opposite to the lower end of the transfer belt 21, and the transfer paper transport path 33 so that the transfer paper 32 passes between the secondary transfer device 31 and the transfer belt 21. The fixing device 34 is provided at the end of the passage between the secondary transfer device 31 and the transfer belt 21.

  The toner image forming process in each of the image forming units 1y to 1k will be described by taking a yellow (Y) toner image forming process as an example. When the photosensitive drum 11y starts rotating, a high voltage is applied to the drum charger 12y, and negative charges are uniformly charged on the surface of the photosensitive drum 11y. Further, the contact roller 22y moves upward, and the transfer belt 21 and the photosensitive drum 11y are contacted. Next, when image information is transmitted from a controller (not shown) to the image forming apparatus, the exposure device 13y controls on / off of the light emission signal in accordance with the image information. As a result, a portion irradiated with laser light from the exposure device 13y and a portion not irradiated with light from the exposure device 13y are formed on the surface of the photosensitive drum 11y, and negative charges are reduced in the portion irradiated with the laser light.

  When the reduced charge portion on the photosensitive drum 11y reaches a position facing the developing unit 14y, the negatively charged toner adheres to the reduced charge portion on the photosensitive drum 11y, and a toner image is formed. The

  When the toner image formed on the photosensitive drum 11y reaches a position where it abuts on the transfer belt 21, the toner image is transferred onto the transfer belt 21 by the action of a high voltage applied to the transfer device 15y. Thereafter, the photosensitive drum 11y that has passed through the portion in contact with the transfer belt 21 passes through the drum cleaning device 16y, and the toner remaining on the surface of the photosensitive drum 11y is removed.

  With respect to the other colors, a toner image is formed on each of the photoconductive drums 11m, 11c, and 11k in the same process, and the toner image is transferred onto the transfer belt 21 so as to overlap to form a full color image.

  The transfer belt 21 is conveyed in the direction of arrow A by a belt driving roller 23. Transfer that is an example of a sheet-like medium that has been conveyed on the transfer paper conveyance path 33 in the direction of arrow B at the same time when the full-color image formed on the transfer belt 21 reaches the portion facing the secondary transfer device 31. The paper 32 reaches the secondary transfer unit 31. Then, a full color image is transferred onto the transfer paper 32 by the action of the high voltage applied to the secondary transfer device 31.

  The full color image transferred onto the transfer paper 32 is melted and fixed when the transfer paper 32 passes through the fixing device 34. On the other hand, the transfer belt 21 that has passed through the portion facing the secondary transfer device 31 passes through the belt cleaning device 24, and the toner remaining on the surface of the transfer belt 21 is removed.

  As described above, the image forming apparatus 100 uses the transfer belt 21, the transfer devices 15 y, 15 m, 15 c, and 15 k and the secondary transfer device 31 to transfer the toner images created by the image forming units 1 y, 1 m, 1 c, and 1 k. Then, the toner image is transferred onto the transfer paper 32, and finally the toner image is fixed on the transfer paper by the fixing device 34.

  However, there are various types of transfer papers distributed in the general market. Transfer paper thickness, size, components, surface smoothness, moisture content, presence / absence of coating agent treatment, coating Each type of agent has different characteristics. If the control contents of the image forming unit, each transfer device, and the fixing device are not adjusted according to such a difference in characteristics, the user cannot obtain a satisfactory output result.

[Examples of normal and defective prints]
FIGS. 3A to 3C are examples of diagrams for explaining defective printed matter. That the output material is such a defective printed material is detected by comparing the document image data received by the image inspection apparatus 103 from the engine 101 with the output image data of the engine 101.

  FIG. 3A shows an example of a phenomenon in which a granular toner concentration portion is generated around a portion where the toner concentration is high (hereinafter referred to as “toner dust abnormality”). This mainly occurs when the current value of the secondary transfer device 31 is too low. On the other hand, when the current value of the secondary transfer unit 31 is too high, a phenomenon in which toner does not adhere (abnormal white point) appears on the transfer paper where the toner should adhere. Hereinafter, a phenomenon in which a granular toner density portion occurs is referred to as toner dust, and a phenomenon in which toner does not adhere to a place where toner should adhere on the transfer paper is referred to as a white point.

  FIG. 3B shows an example of a phenomenon in which the toner density is lighter than the original image (hereinafter referred to as density abnormality). This is because the toner density and toner charge amount in the developing devices 14y, 14m, 14c, and 14k, the charge amount of the photosensitive drums 11y, 11m, 11c, and 11k, the transfer devices 15y, 15m, 15c, and 15k, and the secondary transfer device. The current value of 31 contributes in a complex manner. Hereinafter, this phenomenon is called concentration abnormality.

  FIG. 3C shows an example of a phenomenon in which the image forming position on the transfer paper is shifted (hereinafter referred to as a misregistration error). This occurs when the transfer speed and transfer timing of the transfer sheet are shifted due to the size, thickness and surface smoothness of the transfer sheet. Hereinafter, the deviation in the direction perpendicular to the transfer paper conveyance direction is referred to as main-scanning direction registration deviation, and the deviation in the parallel direction is referred to as sub-scanning direction registration deviation.

[Configuration example of image forming apparatus]
FIG. 4 shows an example of a hardware configuration diagram of the controller 150 of the image forming apparatus 100. The controller 150 of the image forming apparatus 100 has a function as a general computer.

  The image forming apparatus 100 includes a controller 150 that controls the entire image forming apparatus 100, an engine 101 for printing an image on paper, an operation unit 102 that serves as a user interface with an operator, and an output from the engine 101. And an image inspection device 103 for inspection.

  The controller 150 includes a CPU 151, ROM 152, RAM 153, NVRAM 154, network I / F 155, image inspection apparatus I / F 156, engine I / F 157, operation unit I / F 158, HDD 159, and storage medium mounting unit 160.

  The ROM 152 stores a startup program, initial setting values, and the like. The RAM 153 is used as a page memory created by the controller 150 and a work memory necessary for operating software. The NVRAM 154 is a non-volatile memory that stores printing conditions set in the image forming apparatus 100. The network I / F 155 transmits / receives data to / from the server 200 and the PC connected on the network. The image inspection apparatus I / F 156 transmits the document image data generated from the print data received from the PC to the image inspection apparatus 103 and receives the result of comparison with the output image data from the engine 101. The engine I / F 157 controls the engine 101 by issuing a print instruction or the like. The storage medium mounting unit 160 is an I / F for attaching / detaching a portable storage medium (for example, an external storage medium 135 described later).

  The engine 101 has at least the above-described plotter engine that performs image formation. The plotter engine may be an ink jet type. The engine 101 includes a scanner engine and a FAX engine.

  The operation unit 102 includes an input unit and a display unit that are used by an operator to operate the image forming apparatus 100. The input unit is a hard key and various soft keys displayed on the display unit. The display unit is a display means such as a liquid crystal for displaying an operation menu and soft keys on the GUI screen. The display unit is integrally provided with a touch panel, and accepts soft key operations by an operator.

  The panel I / F 158 controls input / output with the operation unit 102. The HDD 159 is an example of a nonvolatile storage unit, and can be replaced with a flash memory or the like. The HDD 159 stores data characteristic of the present embodiment, which will be described later, and a program 161. The program 161 is downloaded and distributed from a server with which the network I / F 155 communicates, or is distributed while being stored in the external storage medium 135.

  FIG. 5 shows an example of a schematic configuration diagram of the image inspection apparatus 103. The image inspection device 103 includes an image reading device 201 and a control device 203. The image inspection apparatus 103 in FIG. 5 discharges (purifies) a defective printed material to a different location from the normal printed material by using the conveyance branch claw 202. A mechanism for marking with a seal or the like may be mounted. In either method, the user can identify the defective printed matter.

  First, the image reading apparatus 201 reads the output product 120 discharged from the engine 101. For example, an image sensor such as a line type or two-dimensional type CCD is attached to the image reading device 201, and an output product is optically read. The image reading apparatus 201 shown in the figure is arranged in two places for reading in parallel with the front and back surfaces of the output object 120. However, the image reading apparatus 201 is arranged only in one place to invert the output object 120, and the front and back surfaces are sequentially arranged. You may read.

  The output image data read by the image reading device 201 is sent to the control device 203. Original image data 122 is sent from the engine 101 to the control device 203 in advance, and the control device 203 outputs the original image data 122 and the output image data while the output 120 is conveyed from the image reading device 201 to the conveyance branch claw 202. Are compared to determine whether the printed matter is defective. If the printed matter is not defective, the control device 203 moves the conveyance branch claw 202 downward, conveys the output matter 120 to the horizontal discharge path 205, and discharges it to the post-processing device 104.

  On the other hand, in the case of a defective printed material, the control device 203 raises the conveyance branch claw 202 to convey the output material 120 to the purge paper discharge path 206 and distinguish it from the normal printed material. Then, the control device 203 generates an image quality correction data group 123 that corrects the image quality abnormality and transmits it to the engine 101.

  Since it is assumed that recovery printing of the defective page is performed after the defective printed matter is discharged, the post-processing device 104 discharges the position of the next normal printed matter after the defective printing. Alternatively, scissor paper (such as cardboard or colored paper) that can be distinguished from normal printed matter may be discharged. By doing so, the image inspection apparatus 103 can discharge the printed material so that the user can grasp the insertion position of the recovery printed material.

  FIG. 6 shows an example of a functional block diagram of the printing system 500. The printing system 500 includes an image forming apparatus 100 and a server 200. Further, a PC 300 may be included. The image forming apparatus 100 mainly includes an operation unit 102, an engine 101, and an image inspection apparatus 103. The engine 101 includes a main body control unit 110, a storage unit 132, a communication unit 131, an external storage medium mounting unit 133, an image inspection apparatus control unit 134, a conveyance control unit 111, a development control unit 112, a transfer control unit 113, and a fixing control. Part 114. The storage unit 132 is, for example, the HDD 159 in FIG. 4, and the communication unit 131 is the network I / F 155 in FIG.

  The external storage medium mounting unit 133 is a mounting unit for the removable external storage medium 135 with the storage medium mounting unit 160 as a substance. The external storage medium 135 is a flash memory such as a USB memory or an SD card, for example, and stores user setting transfer paper data described later. Further, the setting data and the like are distributed in a state of being stored in the external storage medium 135 or distributed in a form downloaded from the server 200.

  The image inspection apparatus control unit 134 controls the image inspection apparatus 103 with the image inspection apparatus I / F 156 as an entity. The document image data 122 received from the document image data creation / transmission unit 54 is sent to the image inspection apparatus 103, and the image quality correction data group 123 obtained as a result of the image comparison is sent to the image quality correction group data receiving unit 52.

  In addition, the CPU 151 executes the program 161 in the main body control unit 110, the conveyance control unit 111, the development control unit 112, the transfer control unit 113, and the fixing control unit 114 that control the entire software as a software control unit. The functions to be provided and the hardware such as the ASIC for controlling the motor and the heater are realized in cooperation.

  The main body control unit 110 controls the entire image forming apparatus 100 such as acquiring a setting data group from the server 200 and storing the setting data group in association with the image quality correction data group 123. The main body control unit 110 further includes a setting data group acquisition unit 51, an image quality correction data group reception unit 52, a user setting transfer paper data transmission unit 53, and a document image data creation / transmission unit 54.

  The setting data group acquisition unit 51 receives the transfer paper brand input by the operator, and transmits the transfer paper brand to the server 200, thereby acquiring the setting data group associated with the transfer paper brand.

  The image quality correction data group receiving unit 52 receives the image quality correction data group 123 from the image inspection apparatus 103 and receives a new transfer paper brand (user set transfer paper brand) to which the image quality correction data group 123 is added from the operator. When the operator inputs a user set transfer paper brand, the image quality correction data group receiving unit 52 duplicates the set data group and associates the user set transfer paper brand with the copied setting data group and image quality correction data group 123. Remember. The user setting transfer paper brand, the duplicated setting data group, and the image quality correction data group 123 are one “user setting transfer paper data”.

  The storage unit 132 stores at least one set data group of general-purpose transfer paper such as plain paper when the image forming apparatus 100 is shipped.

  The user setting transfer paper data transmission unit 53 transmits the identification information of the image forming apparatus 100 and user setting transfer paper data (user setting transfer paper brand, duplicated setting data group and image quality correction data group 123) to the server 200.

  The document image data creation / transmission unit 54 creates document image data and sends it to the image inspection apparatus control unit 134. The document image data has a pixel value for each pixel. In the case of color, the document image data has a pixel value for each pixel of the color image for each CMYK.

  The transport controller 111 controls the transfer paper transport path 33 and controls the position and transport speed of the transfer paper. The development control unit 112 controls the image forming units 1y, 1m, 1c, and 1k, and rotates the photosensitive drums 11y, 11m, 11c, and 11k, the charging voltages of the photosensitive drums 11y, 11m, 11c, and 11k, and the photosensitive drums. The amount of toner attached to the body drums 11y, 11m, 11c, and 11k is controlled. The transfer control unit 113 controls the transfer belt 21, the transfer devices 15y, 15m, 15c, and 15k and the secondary transfer device 31, and the rotation speed of the transfer belt 21, the transfer devices 15y, 15m, 15c, and 15k, and the second transfer device 31 are controlled. The bias voltage of the next transfer device 31 is controlled. The fixing control unit 114 controls the fixing device 34, and controls the temperature of the fixing device and the degree of pressure bonding between the heating rotor and the pressure roller.

  The storage unit 132 stores a setting data group, an image quality correction data group, and a user setting transfer paper brand. These will be described later.

  The transfer paper brand is transfer paper identification information selected by the operator and input from the operation unit 102. The output product 120 is transfer paper on which an image is formed.

  On the other hand, the image inspection apparatus 103 includes a document image data receiving unit 140, an output product optical reading unit 141, an image quality comparison / determination unit 142, and an image quality correction data group creation / transmission unit 143. The document image data receiving unit 140, the output product optical reading unit 141, the image quality comparison / determination unit 142, and the image quality correction data group creation / transmission unit 143 are realized by the control device 203 in FIG. The image inspection apparatus 103 determines whether the image quality is good or bad by comparing the output image data obtained by optically reading the output 120 and the document image data 122, and outputs the inspected output to the post-processing apparatus 104 (not shown). The object 121 is discharged.

  For the output 120 whose determination result is defective printing, the image quality correction data group creation / transmission unit 143 creates the image quality correction data group 123 and transmits it to the image inspection apparatus control unit 134.

  The document image data receiving unit 140 receives the document image data 122 from the image inspection device control unit 134 and temporarily stores the output 120 until it is discharged to the image inspection device 103. The output object optical reading unit 141 corresponds to the image reading apparatus 201 in FIG. 5, has the same function as the scanner engine, and optically converts the front and back images of the output object 120 discharged to the image inspection apparatus 103. To generate output image data.

  The image quality comparison / determination unit 142 compares the output image data generated by the output product optical reading unit 141 with the document image data 122. Various comparison methods are known, but in this embodiment, a method of comparing the difference in density of each part of the image is performed. As a result of the comparison, if there is a color difference equal to or greater than a predetermined reference value, it is determined as defective printing.

  The image quality correction data group creation / transmission unit 143 operates when the image quality comparison / determination unit 142 determines defective printing, analyzes the distribution of density differences on the image obtained from the image quality comparison / determination unit 142, and The type of image quality abnormality as shown in FIG. 3 is specified. After that, an image quality correction data group 123 that corrects the image quality abnormality specified according to the degree of color difference is generated and transmitted to the main body control unit 110.

  The inspected output 121 is a transfer sheet that has undergone image quality comparison / judgment, and includes normal output and defective output. If the determination result is defective printing, the image inspection apparatus 103 labels the defective printed material as defective printed material. For labeling, for example, there are methods such as discharging with a slight shift from other printed materials, attaching sticky notes, and the like.

  As described above, the image forming apparatus 100 is communicably connected to the server 200 by the communication unit 131. The server 200 stores transfer paper setting data group and user setting transfer paper data. Since the setting data group of the server 200 is the original of the setting data group acquired by the image forming apparatus 100, part or all of the setting data group of the server 200 is the same as the setting data group acquired by the image forming apparatus 100. The same applies to the user set transfer paper data.

  The server 200 can also be used as a remote monitoring server that remotely monitors the image forming apparatus 100. The remote monitoring server constantly monitors the image forming apparatus 100 through the firewall and collects the number of printed sheets, the remaining toner amount, error information, and the like. Accordingly, the remote monitoring server dispatches a CE (customer engineer) without causing the image forming apparatus 100 to run out of toner, and prevents the availability of the image forming apparatus 100 from decreasing.

[Abnormal judgment]
FIG. 7 is an example of a flowchart illustrating a procedure in which the image quality comparison / determination unit 142 compares the output image data and the document image data 122. The image quality comparison / determination unit 142 compares the output image data with the following document image data every time one page of output image data is output. In the present embodiment, such comparison may be referred to as “always comparison”.

  First, the image quality comparison / determination unit 142 determines the amount of positional deviation in the transport direction of the output image data (S1). Since the positional deviation in the transport direction occurs in each of the main scanning direction (x direction) and the sub scanning direction (y direction), the positional deviation amount in each of the x direction and the y direction is determined. For determining the amount of misalignment, there are methods of comparing the distance from the paper edge to the black pixel, or using block matching, for example.

FIG. 8 is an example of a diagram illustrating the determination of the amount of misalignment. The image quality comparison / determination unit 142 searches for a black pixel (density is equal to or greater than a threshold value) in the x direction from the paper edge while shifting the position in the y direction. And the coordinate of the y direction of the black pixel is specified. The distance from the paper edge of a black pixel (the apex of “A” in the figure) of the original image data 122 is x0 in the x direction, y0 in the y direction, and the distance from the paper edge of the output image data is x1, y in the x direction. Y1 in the direction. In this case, the positional deviation amount is as follows.
Δx = x0−x1
Δy = y0−y1
Such a method of detecting the misregistration amount is effective for document image data with many documents. The processing load is smaller than when block matching is used, and the detection time can be shortened. Instead of focusing on a part of the character as shown in the figure, a circumscribed rectangle such as a character may be extracted and the positions of the vertices may be compared.

  When block matching is used, the image quality comparison / determination unit 142 fixes the document image data, and extracts, for example, about 3 × 3 pixel blocks centering on the target pixel of the image of the output image data. Then, the position where the pixel values are the same is obtained while shifting the output image data pixel by pixel with respect to the pixels of the fixed document image data. At the overlapping position, the integrated value of the absolute value of the difference between the pixel values of the two images is calculated as an evaluation value, and when the evaluation value is the smallest, the pixel values are the same. By performing this process on all the pixels of the output image data, the overlapping position of the output image data and the document image data 122 is obtained. The method using block matching is effective for image data in which gradation is applied to the output image data and the document image data 122 and it is difficult to specify the distance from the paper edge to the black pixel.

  When the positional deviation amount is equal to or greater than the threshold value 1 (Yes in S2), the image quality comparison / determination unit 142 sets an integer value of 1 to 10 as a positional deviation detection result based on the positional deviation amount (S3). For example, the misregistration detection result represents the misregistration amount in, for example, 10 stages.

  Next, the image quality comparison / determination unit 142 aligns the image data by shifting the output image data in the X direction and the Y direction, respectively, with the document image data fixed. In this state, the pixel values of the output image data and the document image data 122 are compared (S4).

  The image quality comparison / determination unit 142 reads out the pixel value of the document image data in pixel units or block units, and determines whether or not it is a white pixel (S5).

  If it is a white pixel (Yes in S5), it is determined whether the output image data is also a white pixel (S6). Since both images have already been aligned, there is a possibility of some abnormality if the output image data is not a white pixel.

  When the output image data is not a white pixel (Yes in S6), the image quality comparison / determination unit 142 determines whether or not there is a region having a density equal to or higher than a threshold around the output image data (S7). Originally, when the area of the white pixel is not a white pixel and there is an area having a density equal to or higher than the threshold value around the output image data (Yes in S7), there is a possibility that the main body pixel that has caused the black pixel exists. Therefore, the image quality comparison / determination unit 142 counts up one toner dust counter (S9).

  Originally, when the white pixel area is not a white pixel and there is no area having a density of 2 or more around the output image data (No in S7), there is a possibility that an independent toner has adhered to the white pixel area. The image quality comparison / determination unit 142 increments one noise counter (S8).

  When the output image data is a white pixel (No in S6), since the document image data and the output image data are both white, the next pixel or pixel block is processed.

  Returning to step S5, when the document image data is not a white pixel (No in S5), since the document image data includes visible information, the image quality comparison / determination unit 142 determines the pixel values of the document image data and the output image data. It is determined whether or not the difference is equal to or greater than the threshold 3 (S10).

  If there is a difference equal to or greater than the threshold 3 (Yes in S10), the image quality comparison / determination unit 142 determines whether the output image data is a white pixel (S11).

  If the original image data is not a white pixel and the output image data is a white pixel (Yes in S11), there is a possibility of a white point, so the image quality comparison / determination unit 142 increments the white point counter by one ( S13).

  If the original image data is not a white pixel and the output image data is not a white pixel (No in S11), since there is an abnormality in density, the image quality comparison / determination unit 142 increments the density abnormality counter by one (S12). .

  If there is no difference greater than or equal to the threshold 3 (No in S10), the next pixel or pixel block is processed because there is no significant difference in density between the document image data and the output image data.

  The image quality comparison / determination unit 142 performs the processing from steps S5 to S13 over the entire document image data. As a result, a count value is set in the noise counter, the toner dust counter, the density abnormality counter, and the white point counter according to the abnormal content of the output image data. The image quality comparison / determination unit 142 compares the count value of each counter with a reference value, and determines the presence / absence of noise, toner dust, density abnormality, and white point abnormality. A plurality of abnormalities may be found in one page of output image data.

  This figure shows a procedure for determining whether or not there is an abnormality in black and white (monochrome) document image data, but the same can be determined for color document image data. That is, when the document image data is color, the image quality comparison / determination unit 142 may compare the output image data for each of the R element, G element, and B element of the pixel value. Since the output object optical reading unit 141 generates output image data in the RGB color space, the original image data can be easily compared even in color. If the color space of the document image data is not RGB, the image quality comparison / determination unit 142 or the output product optical reading unit 141 converts the color space of the document image data or the output image data.

  Instead of comparing each color element, the output image data and the original image data may be compared after converting RGB into color difference information and luminance information. By doing so, the processing load for image quality comparison can be reduced.

By the way, when compared with the document image data for each page of the output image data, when the output 120 is printed at high speed, the comparison processing may not be in time. There are two main ways to deal with this.
・ Change the error content detected for each page ・ Detect the error from a part of the output image data <When switching the error content detected for each page>
The former will be described. In this case, as a simple method, there is a method of sequentially switching the abnormality content detected for each page. That is,
First page: Steps S1 to S3 (abnormal position error)
Second page: Steps S1 to S9 (detection of noise abnormality and toner dust abnormality)
Third page: Steps S1 to S4, S10 to S13 (abnormal density, over white spot)
This cycle is repeated for the fourth and subsequent pages. In such a method, each abnormality can be detected at least every 3 pages, so even if an abnormality is detected, only 3 pages (actually a little more because there is transfer paper during image formation) is wasted. Image quality correction is possible.

  Also, there may be a tendency for abnormalities that tend to occur depending on the brand of transfer paper. For example, there are cases where toner is difficult to transfer on a certain transfer paper, and excessive toner is placed on another transfer paper. Here, even if the transfer papers of two different transfer paper brands have the same thickness, different abnormalities may occur. Even if the transfer papers of the two different transfer paper brands are both called coated papers, different abnormalities may occur. May occur. Therefore, it is effective to switch the abnormality content to be detected depending on the transfer paper brand.

  FIG. 9 shows an example of the correspondence between the transfer paper brand and the abnormality content to be detected. In this figure, for each transfer paper brand, the likelihood of occurrence of each abnormality content, from a positional deviation abnormality to a noise abnormality, is set in five stages 1-5. The CE can set the likelihood of occurrence of each abnormality.

Based on the transfer paper brand selected by the operator, the image quality comparison / determination unit 142 reads out the likelihood of occurrence of each abnormality from such a correspondence. For example, when printing on the transfer paper A of Company A, it is understood that a positional deviation abnormality is most likely to occur, a toner dust abnormality is most likely to occur next, and white point abnormality and density abnormality are unlikely to occur. In such a case, the image quality comparison / determination unit 142 sets the detection error of the positional deviation abnormality for each page, the detection logic of the toner dust abnormality for every three pages (every two pages), white point abnormality, density abnormality, and Noise abnormality detection logic is performed every 5 to 10 pages. In particular,
Steps S1 to S3 (Position misregistration): Steps S4 to S7 performed for each page, S9 (Toner dust abnormality detection): Steps S1 to S5 performed every 3 pages, S10 to S13: Performed every 5 to 10 pages Thus, even when an image is formed at a high speed, it is possible to detect an abnormality of abnormal contents that is likely to occur for each transfer paper brand. In this case, since the misregistration is detected for each page, if an easily occurring abnormality occurs, only one page (actually a little more because there is a transfer sheet during image formation) is wasted. . Moreover, even if an abnormality that is difficult to occur occurs, only a few pages are wasted.

<When detecting an abnormality from part of the output image data>
In this case, the document image data and the output image data may be divided into regions.
FIG. 10A is an example for explaining the division of the areas of the document image data and the output image data. In the figure, the area is divided into 4 × 6 = 24 areas, but the number of sections can be adjusted according to the image processing speed for detecting an abnormality.

  The image quality comparison / determination unit 142 divides the entire document image data and output image data into, for example, 24 areas. Both are assumed to be already aligned, but may be aligned after the segmentation.

  Then, each area is selectively specified for each page, and an abnormality is detected. Of the 24 regions, which region is to be compared is determined in advance. For example, the image quality comparison / determination unit 142 sets at least a region having a black pixel as a comparison target. Then, the order is specified at predetermined intervals in the main scanning direction and the sub-scanning direction from the region with the black pixel at the upper left, and is used as a comparison target. Alternatively, the comparison target area may be determined at random.

  FIGS. 10B and 10C are examples of diagrams for explaining regions to be detected for image quality abnormality. FIG. 10B illustrates a case where an area having a predetermined width from a, b, and c (pixel positions from the sub-scanning position zero) having the same position in the sub-scanning direction is a detection target of image quality abnormality. Also in this case, the positions of a, b, and c are selected from a region having black pixels.

  FIG. 10C shows a case where an area having a predetermined width from a, b, and c (pixel positions from the main scanning position zero) having the same position in the main scanning direction is a detection target of image quality abnormality. Also in this case, the positions of a, b, and c are selected from a region having black pixels.

  In any case, the image quality comparison / determination unit 142 attempts to detect all abnormalities in the region having the same position in the sub-scanning direction or the region having the same position in the main scanning direction.

  In any of the cases shown in FIGS. 10A to 10C, it is preferable to determine the area so that the inspection of the entire area is always performed once in several pages (for example, 10 pages). By doing so, it is possible to detect local abnormalities of the photoreceptor and the intermediate transfer belt.

  Note that when an abnormality is detected from a part of the output image data, it can be used in combination with a method of preferentially detecting an image quality abnormality that is likely to occur due to the transfer paper brand. In this case, it is preferable to adjust the image quality abnormality detected by the image quality comparison / determination unit 142 for the region so that the relationship between the region and the image quality abnormality to be detected is not fixed.

  In this way, by switching the priority of image quality abnormality detection target based on area classification and transfer paper brand, even if inspection is performed for each page, it becomes easy to support high-speed printing, and image quality abnormality can be detected efficiently. it can.

[Setting data group]
FIG. 11 is a diagram illustrating an example of the setting data group. The setting data group can be stored in either the image forming apparatus 100 or the server 200, but the format is the same. One row has one setting data group, each setting item in one row has one setting data (the setting data group in the figure has three setting data), and the whole of FIG. 11 is a list (list) of setting data groups. It is.

  The setting data group includes setting data such as a secondary transfer reference current, a fixing device temperature, and a linear velocity correction value associated with the transfer paper brand. These three are examples, and include a lot of information such as a voltage value and a current value that affect the image quality of the transfer paper. There are two main types of setting data group registration. One is a mode in which a specialized institution registers, and the other is a mode in which a CE operating the image forming apparatus 100 registers.

First, the transfer paper brand is the name of the transfer paper determined when the transfer paper is evaluated at a facility specializing in evaluation of the transfer paper. The transfer paper brand is applied as follows, for example.
{Name of transfer paper manufacturer or distributor + transfer paper product name + transfer paper attributes that affect image quality}
In FIG. 11, transfer paper product names (transfer paper A, transfer paper B, transfer paper C) are combined with the company name (company A, company B) of the manufacturer or distributor of the transfer paper. Since the product name usually includes distinction between plain paper, glossy paper, matte paper, envelope paper, and film, a considerable amount of transfer paper can be distinguished by distinguishing by product name.

In the figure, the attributes of transfer paper that affect image quality are omitted, but these attributes include thickness (g / m ² ), size, and so on. By including different attributes in the transfer paper brand, it is possible to call an appropriate set data group if the operator selects the correct transfer paper brand.

  In addition to the transfer paper brand, the server 200 is assigned a transfer paper ID for uniquely identifying the transfer paper brand.

  In addition, the specialized organization does not determine the transfer paper brand and the setting data group, but the CE that has determined the setting data group by operating the image forming apparatus 100 transmits the transfer paper brand and the setting data group to the server 200. Transfer paper brands and setting data groups can be registered.

  In this case, the CE assigns the transfer paper brand according to the rules for assigning the transfer paper brand. Alternatively, the CE may send transfer paper information (manufacturer, etc.) to the server 200 and request the server 200 to give the transfer paper brand. The information on the transfer paper is included in a barcode printed on a package that wraps the transfer paper. The image forming apparatus 100 reads and decodes the bar code, extracts transfer paper data such as thickness and size from the decoded information, and transmits it to the server 200. The server 200 assigns the transfer paper brand and stores it with the set data group.

  Since the setting data registered by the CE via the image forming apparatus 100 is also preferably stored in the image forming apparatus 100, the server 200 transmits the assigned transfer paper brand to the image forming apparatus 100. Accordingly, the image forming apparatus 100 can store the setting data group in association with the transfer paper brand common to the server 200.

  The secondary transfer reference current is a current value for controlling the bias voltage supplied to the secondary transfer unit 31 by the transfer control unit 113. The larger the secondary transfer reference current is, the higher the bias voltage of the secondary transfer device 31 is, and the toner image is easily transferred from the transfer belt to the transfer paper. However, an excessively high value may cause inconvenience in the electric strength performance of the member. Therefore, an appropriate value is set based on the evaluation result of the specialized facility.

  The fixing device temperature is the temperature of the heating roller of the fixing device. In general, the higher the fixing temperature, the better the fixing property of the toner onto the transfer paper, but it is known that the gloss is lowered when the fixing temperature is excessively high. For this reason, an appropriate value is set based on the evaluation result of the specialized facility.

  The linear velocity correction value is a correction value for correcting the surface speed of the transfer belt 21 and the photosensitive drums 11y, 11m, 11c, and 11k, and the conveyance speed of the transfer paper 32 conveyed through the transfer paper conveyance path 33. A higher transfer belt surface speed improves productivity. However, an excessively high speed causes image blurring, and an excessively slow transfer belt deteriorates transferability. For this reason, an appropriate value is set based on the evaluation result of the specialized facility.

  The image forming apparatus 100 acquires the transfer paper brand from the setting data group as shown in FIG. 11 from the server 200 at the time of activation, for example, once a day or periodically, and stores it in the storage unit 132. Also, the transfer paper setting data group once used by the operator is cached and stored in the storage means 132.

  The operator operates the operation unit 101 to display a list of transfer paper brands, and selects a transfer paper brand of the transfer paper to be used from the list. Then, the setting data group acquisition unit 51 of the main body control unit 102 causes the communication unit 131 to transmit the transfer paper brand and acquires the transfer paper brand setting data group to be used from the server 200. By doing so, the user can print with a set data group that is optimal for the transfer paper brand to be used.

  In addition, the operator can input the transfer paper brand by manual operation from the operation unit 101 instead of selecting the transfer paper brand from the list. The operator can also input the transfer paper brand by causing the image forming apparatus 100 to read the barcode printed on the package that wraps the transfer paper. Note that there may be a situation where the transfer paper brand of the transfer paper prepared (purchased) by the user is not registered in the server 200. In this case, the operator sets the type of transfer paper (plain paper, glossy paper, matte paper, etc.), thickness, and size (hereinafter collectively referred to as transfer paper data) from the operation unit 101. The main body control unit 102 identifies the transfer paper brand closest to the input transfer paper data from among the transfer paper stored in the storage unit 132, and executes printing with the set data group of the transfer paper brand.

[Image quality correction data group]
The image quality correction data group will be described with reference to FIG. The image quality correction data group is registered for each transfer paper brand. The setting data group is an image forming parameter that allows the specialized facility or the CE to obtain the best image quality with the transfer paper brand. However, when printing is performed using the setting data group, a high-quality output 120 is not necessarily obtained. Not necessarily. This is because the quality of the output 120 is affected by the storage conditions of the transfer paper and the image forming apparatus itself such as the room temperature and humidity, and the operating conditions such as the internal temperature and internal humidity of the apparatus. In this case, as described above, the image inspection apparatus 103 detects a defect in the image quality of the output object 120.

  In such a case, the image inspection apparatus 103 prepares the image quality correction value of the image quality correction data group according to the inspection result, and notifies the operator that recovery printing is possible. The operator can instruct recovery printing with fine adjustment of image quality by operating the operation unit 102 by visually observing the operation unit 102.

  FIG. 13 is a diagram illustrating an example of an image quality correction data group creation table for the image quality correction data group creation / transmission unit 143 to generate the image quality correction data group 123. The image quality correction data group creation table in the figure is for converting the count value TC of the toner dust counter into a toner dust adjustment value. The image quality correction data group creation / transmission unit 143 reads out the toner dust adjustment value associated with the count value TC of the toner dust counter, and sets it as the toner dust adjustment value of the image quality correction data group. Other adjustment values can be set similarly. Instead of referring to such a table, the toner dust adjustment value can be obtained by inputting the count value TC of the toner dust counter into the function.

  Note that the image forming apparatus 500 mainly adjusts the current value of the secondary transfer device 31 for the toner dust abnormality, but for the density abnormality, the toner concentration and the toner charge amount in the developing machine 14 and the photosensitive drum 11 The charge amount, the current value of the transfer device 15 and the secondary transfer device 31, and the like are adjusted. Thus, the setting data group and the image quality correction data group do not correspond one-to-one. The development control unit 112 increases or decreases all the setting data affected by the image quality correction data group to form an image. By doing this, it is possible to determine whether or not there is an abnormality one by one and to reflect the detection result of the image quality abnormality in the setting data group at the time of image formation, so that an inspected output with reduced abnormality over all pages can be obtained. .

[Operation procedure]
FIG. 14 is a flowchart illustrating an example of an operation procedure in which the printing system executes printing using the image quality correction data group.

  First, the user prepares transfer paper and inputs a transfer paper brand (So-1). The user can input by selecting the transfer paper brand of the transfer paper prepared from the transfer paper brand list displayed on the operation unit 102, or the image forming apparatus 100 can read the barcode printed on the transfer paper packaging. It is also possible to input it.

  The setting data group acquisition unit 51 of the main body control unit 110 receives an input of a transfer paper brand (Sg-1).

  The setting data group acquisition unit 51 determines whether or not the input transfer paper brand is stored in the storage unit 132 (Sg-2). A transfer paper brand setting data group that has already been used and a transfer paper brand setting data group registered by the image forming apparatus 100 in some cases may already be stored in the storage unit 132.

  When the input transfer paper brand is registered in the list of setting data groups (Yes in Sg-2), the main body control unit 110 reads out the setting data group associated with the transfer paper brand and further transfers the transfer paper brand. If the image quality correction data group is associated with the image quality correction data group, the image quality correction data group is read (Sg-7). In this case, the process proceeds to an image forming process (Sg-8).

  When the input transfer paper brand is not registered in the list of setting data groups (No in Sg-2), the setting data group acquisition unit 51 of the main body control unit 110 transmits the transfer paper brand to the server 200 (Sg- 3).

  The server 200 receives the transfer paper brand from the image forming apparatus 100 (Ss-1). Then, the server 200 determines whether or not the transfer paper brand setting data group is stored (Ss-2).

  When the transfer paper brand setting data group is stored (Yes in Ss-2), the server 200 transmits the setting data group to the image forming apparatus 100 (Ss-3).

  When the transfer paper brand setting data is not stored (No in Ss-2), the server 200 transmits to the image forming apparatus 100 that the setting data group is not stored (Ss-4). The server 200 records the transfer paper brand that is found not to be stored, and prompts the staff of the specialized institution to determine the set data group immediately. The setting data group acquisition unit 51 of the image forming apparatus 100 receives from the server 200 that there is no setting data group or setting data group (Sg-4).

  The setting data group acquisition unit 51 of the main body control unit 110 determines whether there is no setting data group associated with the transfer paper brand in the server 200 based on the received content (Sg-5).

  When the setting data group can be received from the server 200 (No in Sg-5), the main body control unit 110 starts image formation using the setting data group.

  When the setting data group cannot be received from the server 200 (Yes in Sg-5), the main body control unit 110 displays a message indicating that the setting data group does not exist on the operation unit 102 and selects (inputs) the transfer paper data. Prompt.

  Thereby, the operator can select (input) the transfer paper data (So-2). The operator inputs transfer sheet characteristics such as the type, thickness, and size of the transfer sheet from the operation unit 102.

  The main body control unit 110 of the image forming apparatus 100 receives input of transfer sheet data (Sg-6). Then, the main body control unit 110 identifies the transfer paper brand closest to the input transfer paper data among the transfer papers stored in the list of setting data groups, and the setting data group associated with the transfer paper brand. Is read.

  Since transfer paper data such as the type, thickness, and size of the transfer paper is linked to the transfer paper brand of the setting data group, the main body control unit 110 first has the same type as the transfer paper input by the operator. The types of transfer paper brands are extracted from the list of setting data groups. Then, the transfer paper brand with the closest thickness and type is identified. If there are a plurality of transfer papers satisfying these conditions, the transfer paper brand having the closest size is specified. If the transfer paper brand can be specified, the set data group can also be specified.

  As described above, since the main body control unit 110 has acquired the setting data group, or the setting data group and the image quality correction data group, image formation is performed (Sg-8).

  Specifically, when only the setting data group is acquired, the main body control unit 110 sets the secondary transfer reference current, the fixing device temperature, the linear velocity correction, and the like of the setting data group as operation parameters, respectively, and the conveyance control unit 111, development Set in the control unit 112, the transfer control unit 113, and the fixing control unit 114.

  Further, when acquiring the setting data group and the image quality correction data group, the main body control unit 110 increases / decreases corresponding setting data based on the setting data group based on the image quality correction data group, converts the setting data into operation parameters, and performs conveyance control. Are set in the section 111, the development control section 112, the transfer control section 113, and the fixing control section 114.

  When the main body control unit 110 requests each unit to start a control operation, each control unit performs an operation according to an operation parameter given to each unit, and forms an image on a transfer sheet. Also, the print data that is the forming source given to the main body control unit 110 is transmitted as document image data 122 from the image inspection device control unit 134 to the image inspection device 103.

  When the image is formed on the transfer sheet, the main body control unit 110 discharges the transfer sheet as the output 120 to the image inspection apparatus 103 and requests image inspection. The image inspection apparatus 103 performs image inspection when the document image data 122 and the output 120 are ready (Sg-9). The image inspection apparatus 103 optically reads the output object 120 by the output object optical reading unit 141 and generates output image data, and then compares the colors of the output image data and the document image data 122. As a result of the comparison, it is determined whether or not there is an abnormality in the output image data based on whether or not the color difference is larger than a threshold value set in advance in the image inspection apparatus 103 (Sg-10).

  When there is no abnormality in the output image data (No in Sg-10), the output 120 is directly output to the post-processing device 104 as the inspected output 121.

  If there is an abnormality in the output image (Yes in Sg-10), the image inspection apparatus 103 labels the output matter 120 as a defective printed matter and discharges it to the post-processing device 104 as the inspected output matter 121. Thereafter, a message indicating that a defective printed matter has occurred is displayed on the operation unit 102 and prompts selection (input) as to whether or not to perform recovery printing.

  Accordingly, the operator can select (input) whether or not recovery printing is to be performed on the image forming apparatus 100 (So-3). The operator selects (inputs) whether or not to perform recovery printing from the operation unit 102.

  The main body control unit 110 accepts whether or not to perform recovery printing from the operator (Sg-11), and determines whether or not to perform recovery printing (Sg-12).

  When recovery printing is not performed (No in Sg-12), information on what type of defective printing has occurred is displayed on the operation unit 102, and notification is made of an apparatus failure (Sg-17).

  When performing recovery printing (Yes in Sg-12), the main body control unit 110 requests the image inspection apparatus 103 to transmit an image quality correction data group. The image inspection apparatus 103 identifies the type of defect printing from the inspection result, creates an image quality correction data group, and transmits it to the image quality correction data group reception unit 52 of the main body control unit 110 (Sg-13). When the image quality correction data group reception unit 52 receives the image quality correction data group, the main body control unit 110 performs image formation (recovery printing) again with the setting data group and the received image quality correction data group (Sg-14). Specific contents of the image forming operation are as described above. Similarly, the main body control unit 110 transmits the document image data 122 to the image inspection apparatus 103.

  When an image is formed on the transfer paper, the main body control unit 110 discharges the transfer paper to the image inspection apparatus 103 as an output 120 and requests image inspection again. The image inspection apparatus 103 performs image inspection when the document image data 122 and the output 120 are ready (Sg-15). The specific content of the image inspection operation is as described above, and it is determined again whether there is an abnormality in the output image (Sg-16).

  If there is an abnormality in the output image (Yes in Sg-16), the printing system determines that the defective printing cannot be resolved, displays information on what type of defective printing has occurred on the operation unit 102, and the device Notify as failure (Sg-17).

  When there is no abnormality in the output image (Sg16-No), the main body control unit 110 displays on the operation unit 102 that a brand can be input as a user-set transfer sheet to the set of the setting data group and the image quality correction data group, and the user setting transfer Prompt for paper brands.

  As a result, the operator can select (input) the user-set transfer paper brand (So-4). The operator inputs a user-set transfer paper brand from the operation unit 102.

  The main body control unit 110 receives the user set transfer paper brand from the operator, and stores the combination of the user set transfer paper brand, the set data group, and the image quality correction data group as user set transfer paper data in the storage unit 132 (Sg-18).

  As described above, the printing system 500 can improve the image forming conditions by the image quality correction data group even if a defective printed material is output on a certain brand of transfer paper. In this case, defective printing can be suppressed. Further, even if the correction is reflected on the transfer paper of a certain brand, the print quality of the transfer paper of another brand is not lowered.

  In the first embodiment, the printing system 500 that can associate one image quality correction data group with one transfer paper brand has been described. However, even for the same transfer paper brand, the characteristics may differ depending on the storage status of the transfer paper and the image forming apparatus itself such as the room temperature and humidity, and the operating status such as the internal temperature and internal humidity of the apparatus. In this case, it is convenient if different image quality correction data groups are associated with one setting data group.

  FIG. 15 is an example of a diagram schematically illustrating the setting data group and the image quality correction data group. As shown in the drawing, “A company transfer paper A user setting 1” is registered in the transfer paper brand. Since the setting data group of the set of the setting data group and the image quality correction data group is the setting data group of “A company transfer paper A”, the image quality correction data group receiving unit 52 sets the setting data of “A company transfer paper A”. The group is duplicated in a record of “Company A transfer sheet A user setting 1”.

  Further, the image quality correction data group receiving unit 52 sets the image quality correction data group created by the image inspection apparatus 103 in the field of the image quality correction data group of the record of “Company A transfer sheet A user setting 1” from the operation unit 102. The set user setting transfer paper brand is registered (overwritten) in the transfer paper brand field of the record “A company transfer paper A user setting 1”.

  As described above, since the operator can freely assign a name to the set of the copied setting data group and image quality correction data group, a plurality of image quality corrections can be performed on one setting data group acquired from the server 200 by the image forming apparatus 100. Data groups can be stored in association with each other. The user setting transfer paper brand, the duplicated setting data group, and the image quality correction data group of one record are the user setting transfer paper data.

  Further, the user setting transfer paper data transmission unit 53 transmits the user setting transfer paper data to the server 200 when the operator assigns the user setting transfer paper brand to the set of the setting data group and the image quality correction data group.

  If the user-set transfer paper data transmission unit 53 transmits only the image quality correction data group to the server 200, the server 200 needs to manage the association between the transfer paper brand and the image quality correction data group. For example, even if a plurality of image quality correction data groups are associated with one transfer paper brand, the transfer paper brand and image quality correction data group set can be selected by the user so that the user can select a desired set data group and image quality correction data group. It is necessary to give a new transfer paper brand to the user.

  However, in FIG. 15, since the operator has already assigned the user set transfer paper brand to the set of the set data group and the image quality correction data group, the server 200 may store the user set transfer paper data as it is. However, since another user may give the same user setting transfer paper brand to the set of the setting data group and the fine adjustment data, the server 200 uses the identification information of the image forming apparatus 100 as the user setting transfer paper brand, setting. It is preferable to register together with the data group and the image quality correction data group.

  Once the user-set transfer paper data registered in the server 200 is specified by the server 200 and transmitted to the image forming apparatus 100 simply by the operator specifying the user-set transfer paper brand, the user is determined by a specialized facility. It can be used by the user in the same way as the setting data group. Note that the identification information (for example, IP address) of the image forming apparatus is transmitted to the server regardless of whether the operator is aware or not, so that the server can identify the image forming apparatus that transmitted the user-set transfer sheet data. it can.

  The operator can also copy the user set transfer paper data stored in the storage unit 132 to the external storage medium 135 by operating the operation unit 102. The user-set transfer paper data can be saved by the operator on a PC or the like.

  In addition, when the operator wants a plurality of image forming apparatuses 100 to execute printing with the same image quality correction data group, the image forming apparatus 100 reads the user set transfer paper data in the external storage medium 135. As a result, a plurality of image forming apparatuses 100 in the user can print with the same image quality correction data group, and the image quality can be easily unified in the company.

  As described above, in the printing system 500 of this embodiment, the operator can assign a user-set transfer paper brand to a set of the setting data group and the image quality correction data group. Therefore, a plurality of image quality correction data groups are included in one setting data group. Can be associated. Further, the server 200 can manage a plurality of image quality correction data groups in association with one setting data group without changing the original setting data group, and the user downloads the user setting transfer paper data. Can print. In addition, since each user assigns and manages a user-set transfer paper brand to a set of setting data and image quality correction data group, even if the server 200 stores the user-set transfer paper data, the load on the server 200 is greatly increased. Nor.

  In the first and second embodiments, the generation of the image quality correction data group has been mainly described. In the present embodiment, management of the image forming apparatus 100 using the image quality correction data group will be described.

  FIG. 16 shows an example of a hardware configuration diagram of the server 200. The server 200 includes a CPU 201, a ROM 202, a RAM 203, an HDD 204, a storage medium mounting unit 205, a NIC (Network Interface Card) 206, an input device 207, and a display control unit 208. Since the configuration of such a server 200 is known, a description thereof will be omitted. The HDD 204 stores a program 210.

  FIG. 17 shows an example of a functional block diagram of the server 200. The server 200 includes an image quality correction data group collection unit 61, an apparatus failure (prediction) determination unit 62, and a user setting transfer paper data DB 63.

  The image forming apparatus 100 transmits user setting transfer sheet data to the server 200. The image quality correction data group collection unit 61 of the server 200 receives, for example, user-set transfer paper data that the image forming apparatus 100 periodically transmits, and stores it in the user-set transfer paper data DB 63 in association with the identification information of the image forming apparatus 100. Remember.

  In this embodiment, the image forming apparatus 100 transmits identification information of the image forming apparatus 100 (for example, a manufacturing machine number stored in the storage unit 132) so that the server 200 can identify the image forming apparatus 100 that is the transmission source. To do.

  As a result, the server 200 can obtain collected data as shown in FIG. In the collected data in the figure, “user set transfer paper brand”, “transfer paper brand”, and “image quality correction data group” are registered in association with the identification information of the image forming apparatus 100. Since it is difficult for the server 200 to link the “user-set transfer paper brand” and the “transfer paper brand”, the image forming apparatus 100 sets the server 200 to register the transfer paper brand in the collected data as shown in FIG. The transfer paper brand that is the copy source of the data group is also transmitted.

  The server 200 uses the image quality correction data group to determine the type of defective printed matter and the degree of defect. Depending on which part of the image quality correction data group a value other than 0 is input, the type of defective printed matter and the degree of defect are obtained by the absolute value of the image quality correction data group. For example, when the image forming apparatus 100 is normal (assuming that it is normal) but the absolute value of a certain part of the image quality correction data group is large, it is expected that the transfer sheet is a special transfer sheet. In this case, if the transfer paper is not evaluated by a specialized institution, it is understood that the specialized institution should urgently evaluate it. On the other hand, when the transfer paper has been evaluated by a specialized institution, it is estimated that the evaluation of the transfer paper by the specialized institution is not appropriate.

  Further, if it is unclear whether the image forming apparatus 100 is normal, there may be a case where the absolute value of a certain part of the image quality correction data group is large, for example, a sign of the life or failure of the apparatus.

  Therefore, the image quality correction data group is important information for CEs that perform apparatus maintenance and transfer sheet evaluation. When the image forming apparatus 100 having the image quality correction data group having a large degree of defect is detected, the CE visits a user in which the image forming apparatus 100 is installed. If there is no sign of abnormality in the image forming apparatus 100 or if there is no sign of abnormality, the image quality correction data group of the image forming apparatus 100 can be used as a reference for future transfer sheet evaluation.

  The apparatus failure (prediction) determination unit 62 of the server 200 reads out the image quality correction data group and determines whether or not the CE should be visited because the degree of defects is large. For example, the apparatus failure (prediction) determination unit 62 takes out the absolute value of each item of the image quality correction data group, and identifies the image forming apparatus 100 when at least one absolute value of each item of the image quality correction data group is equal to or greater than a threshold value. Read the information and notify the CE. Any notification method may be used. For example, an e-mail in which the identification information of the image forming apparatus 100 and user-set transfer paper data are described is transmitted to the CE mail address.

  It is also effective to make a comparison only with image quality correction data groups of the same transfer paper brand. For example, for company A transfer paper A, many image forming apparatuses 100 register relatively small absolute image quality correction values, but some image forming apparatuses 100 register large image quality correction values. In this case, there is a possibility that the image forming apparatus 100 has a sign of abnormality.

  In this case, the apparatus failure (prediction) determination unit 62 calculates an average value or a standard deviation for each item in the image quality correction data group of the same transfer paper brand, and determines whether or not there is an abnormality sign in the image forming apparatus 100. Can be determined.

  FIG. 19 is a diagram illustrating an example of image quality correction data group for each transfer sheet managed by the user setting transfer sheet data DB 63 in the server 200 illustrated in FIG. For transfer paper A of Company A, in the image quality correction data group by transfer paper, the image density adjustment of the image forming apparatus 100 with the identification information “0001” is “−1”, and the image density of the image forming apparatus 100 with the identification information “0003” is Adjustment is “0”. On the other hand, the image density adjustment of the image forming apparatus 100 with the identification information “0002” is “+5”.

  The apparatus failure (prediction) determination unit 62 determines whether or not the image density adjustment “+5” falls within the average value ± standard deviation. If not, the identification information “0002” of the image forming apparatus 100 and the user setting transfer are determined. Paper data is read and notified to the CE. In this way, it is possible to infer that an abnormal image is likely to occur by paying attention to the image quality correction data for one transfer paper called Company A transfer paper A, and take measures such as dispatching a CE to the apparatus. be able to.

  FIG. 20 is an example of a flowchart illustrating a procedure for the server 200 to identify the image forming apparatus 100 having an abnormality sign. The procedure in FIG. 20 is started, for example, when a new image quality correction data group is registered in the image forming apparatus 100 or when the image forming apparatus 100 periodically transmits user-set transfer sheet data to the server 200. .

  First, the user setting transfer paper data transmission unit 53 of the image forming apparatus 100 transmits the identification information of the image forming apparatus 100 and the user setting transfer paper data (including the copy source brand of the copy source) to the server 200 ( Sg-21).

  The image quality correction data group collection unit 61 of the server 200 receives the identification information of the image forming apparatus 100, the user set transfer paper data, and the copy source brand of the copy source (Ss-21). The image quality correction data group collection unit 61 stores the user setting transfer paper brand, the transfer paper brand, and the image quality correction data group in the user setting transfer paper data DB 63 in association with the identification information of the image forming apparatus 100.

  The failure (prediction) determination unit 62 reads the user-set transfer paper data DB 63 and determines whether the image quality correction value of the image quality correction data group exceeds the threshold value for each case (Ss-22).

  If the image quality correction value of the image quality correction data group does not exceed the threshold value (No in Ss-22), the failure (prediction) determination unit 62 does nothing, and the next image quality correction data group in the user set transfer paper data FB63 is selected. Read it out.

  When the fine adjustment value of the fine adjustment data exceeds the threshold (Yes in Ss-22), the failure (prediction) determination unit 62 notifies the identification information and the image quality correction data group of the image forming apparatus 100 to the CE (Ss -twenty three).

  As described above, the printing system 500 according to the present embodiment detects signs of abnormality in the image forming apparatus 100 at an early stage by monitoring the image quality correction data group, and detects the use of special transfer paper. Can do. Further, by monitoring the image quality correction data group for each transfer sheet, it is possible to accurately detect an abnormality sign of the image forming apparatus 100.

  In the third embodiment, the failure (prediction) determination unit 62 does not perform specific processing when the image quality correction value of the image quality correction data group does not exceed the threshold value. However, the image quality correction value does not exceed the threshold value, but the image quality correction value other than “0” means that some image quality abnormality is detected. In addition, the image quality abnormality may easily occur with a certain transfer paper brand. Therefore, in the future, when there is a user who uses a transfer paper brand whose image quality correction value does not exceed the threshold value but whose image quality correction value is other than “0”, the image forming apparatus preferentially detects the image quality abnormality. Therefore, the processing load for detecting an image quality abnormality can be reduced.

  FIG. 21 shows an example of a functional block diagram of the server 200 of the present embodiment. In FIG. 21, the same parts as those in FIG. The server 200 of this embodiment includes an image quality correction value transmission unit 64. The image quality correction value transmission unit 64 transmits the image quality correction value of the image forming apparatus and the transfer paper brand that the apparatus failure (prediction) determination unit 62 has determined not to have failed to the image quality inspection apparatus 103 of the image forming apparatus.

  Depending on the model (model number) of the image forming apparatus, there may be an image quality abnormality that tends to occur and an image quality abnormality that hardly occurs even with the same transfer paper brand. For this reason, the image quality correction value and the transfer sheet are used only for the image forming apparatus of the same model number and the image forming apparatus of the user who uses the transfer paper brand whose image quality correction value does not exceed the threshold but the image quality correction value is other than “0”. You may send a stock.

  When image formation is performed on the received transfer paper brand, the image quality comparison / determination unit 142 of the image quality inspection apparatus 103 switches the image quality abnormality detected preferentially according to the received image quality correction value. For example, in a certain transfer paper brand, when the toner dust adjustment value is larger than the other adjustment values in the image quality correction value group, the toner dust abnormality is preferentially detected. By so doing, it is possible to efficiently detect image quality anomalies for high-speed printing.

  FIG. 22 is an example of a flowchart illustrating an operation procedure of the printing system. The procedure of FIG. 22 starts when, for example, the server 200 acquires a transfer paper brand whose image quality correction value does not exceed the threshold value but whose image quality correction value is other than “0”.

  The image quality correction value transmission unit 64 transmits the transfer paper brand and the image quality correction value group to the image forming apparatus 100 (Ss-31).

  The communication unit 131 of the image forming apparatus receives the transfer paper brand and the image quality correction value group (Sg-31). The main body control unit 110 transmits the transfer paper brand and the image quality correction value group to the image quality inspection apparatus 103.

  When the image forming apparatus accepts the transfer paper brand to start printing, the image quality comparison / determination unit 142 receives the set of the image quality correction value and the transfer paper brand from the server 200 and determines whether or not the transfer paper brand is printed. (Sg-32).

  When the image quality correction value is not printed on the received transfer paper brand (No in Sg-32), since there is no record of abnormal image quality, the image quality abnormality is detected as in the first embodiment (Sg-34). That is, the abnormality of image quality is detected by switching the abnormality content to be detected for each page or detecting the abnormality from a part of the output image data.

  When the image quality correction value is printed on the received transfer paper brand (Yes in Sg-32), the image quality comparison / determination unit 142 preferentially detects an image quality abnormality with a large image quality correction value over other image quality abnormalities (Sg -33). For example, when the toner dust adjustment value is large, the toner dust abnormality is detected every page, and the white point abnormality is detected every three pages.

  According to the present embodiment, the server collects transfer paper brands and image quality correction value groups, so that each image forming apparatus efficiently monitors abnormal images when transferring to a specific transfer paper brand. Can make it possible.

DESCRIPTION OF SYMBOLS 21 Transfer belt 31 Secondary transfer device 34 Fixing device 51 Setting data group acquisition part 52 Image quality correction data group reception part 53 User setting transfer paper data transmission part 54 Original image data creation / transmission part 61 Image quality correction data group collection part 62 Apparatus Failure (prediction) determination unit 63 User set transfer paper data DB
64 Image quality correction value transmission unit 100 Image forming device 101 Engine 102 Operation unit 103 Image inspection device 104 Post-processing device 110 Main body control unit 111 Conveyance control unit 112 Development control unit 113 Transfer control unit 114 Fixing control unit 120 Output object 121 Inspected output Object 131 Communication means 132 Storage means 133 External storage medium mounting section 134 Image inspection apparatus control section 135 External recording medium 140 Document image data reception section 141 Output object optical reading section 142 Image quality comparison / determination section 143 Image quality correction data group creation / transmission section 200 Server 201 Image Reading Device 500 Printing System

JP 2007-088985 A JP 2002-82496 A

Claims (8)

An image forming apparatus for forming an image on transfer paper,
Information receiving means for receiving input of transfer sheet identification information;
Document image data acquisition means for acquiring document image data of the image;
An image forming unit configured to apply an image forming process control value associated with the transfer sheet identification information received by the information receiving unit to the image forming process to form an image of document image data on the transfer sheet;
Output image data generating means for optically reading an image formed on the transfer paper and generating output image data;
A printed matter inspection means for comparing original image data and output image data for each page of output image data to detect image quality anomalies in the output image data;
When an image quality abnormality is detected in the output image data, a correction value for the control value that reduces the image quality abnormality is created based on the content and level of the image quality abnormality, and stored in the storage unit in association with the transfer sheet identification information Value creation means;
An image quality abnormality table in which types of image quality anomalies that are likely to occur on the transfer paper are associated with the transfer paper identification information ;
When the correction value is associated with the transfer sheet identification information received by the information receiving unit, the image forming unit applies the control value corrected by the correction value to the image forming process to transfer paper An image of the original image data is formed on
The printed matter inspection unit divides the document image data and the output image data into a plurality of regions having the same number and shape, respectively, and compares only a part of the plurality of regions to detect an image quality abnormality in the output image data. In the image quality abnormality table , the image quality abnormality associated with the transfer sheet identification information received by the information reception unit is detected with priority over other image quality abnormalities,
Further, the areas are compared so that the entire area of the output image data is rotated once for each predetermined number of output image data.
An image forming apparatus. The information receiving means receives input of user-set transfer paper identification information from a user,
Storage means for copying the control value and the correction value associated with the transfer sheet identification information and storing the copied control value and the correction value in association with the user set transfer sheet identification information. The image forming apparatus according to claim 1. Transmitting the transfer sheet identification information received by the information receiving means to an external information processing apparatus, and setting data group acquisition means for acquiring the control value and the correction value of the transfer sheet identification information from the external information processing apparatus, The image forming apparatus according to claim 2 . The image forming apparatus according to claim 2 , further comprising an external recording medium access unit that records the correction value and the control value stored in association with the user-set transfer sheet identification information on an external recording medium. . User-set transfer sheet data transmission means for transmitting the correction value, the control value, and the identification information of the image forming apparatus stored in association with the user-set transfer sheet identification information to an external information processing apparatus; ,
The setting data group acquisition unit specifies the user setting transfer sheet identification information and the identification information of the image forming apparatus, and acquires the correction value and the control value from an external information processing apparatus.
The image forming apparatus according to claim 3. The setting data group acquiring means compares the correction value for each said transfer sheet identifying information external information processing apparatus is acquired from a plurality of image forming apparatuses, abnormality occurs to determine dolphin whether the image forming apparatus Acquiring the control value and the correction value of the transfer sheet identification information acquired from the image forming apparatus determined that no abnormality has occurred from an external information processing apparatus,
The printed matter inspecting unit detects the image quality abnormality determined to require correction of the control value based on the correction value in preference to other image quality abnormality;
The image forming apparatus according to claim 3 . A printing system in which an external information processing apparatus and an image forming apparatus that forms an image on transfer paper are connected via a network,
Information receiving means for receiving input of transfer sheet identification information;
Document image data acquisition means for acquiring document image data of the image;
An image forming unit configured to apply an image forming process control value associated with the transfer sheet identification information received by the information receiving unit to the image forming process to form an image of document image data on the transfer sheet;
Output image data generating means for optically reading an image formed on the transfer paper and generating output image data;
A printed matter inspection means for comparing original image data and output image data for each page of output image data to detect image quality anomalies in the output image data;
When an image quality abnormality is detected in the output image data, a correction value for the control value that reduces the image quality abnormality is created based on the content and level of the image quality abnormality, and stored in the storage unit in association with the transfer sheet identification information And a value creating means,
When the correction value is associated with the transfer sheet identification information received by the information receiving unit, the image forming unit applies the control value corrected by the correction value to the image forming process to transfer paper An image of the original image data is formed on
The printed matter inspection unit divides the document image data and the output image data into a plurality of regions having the same number and shape, respectively, and compares only a part of the plurality of regions to detect an image quality abnormality in the output image data. Is what
In the image quality abnormality table in which the type of image quality abnormality that is likely to occur on the transfer paper is associated with the transfer paper identification information, the image quality abnormality associated with the transfer paper identification information received by the information receiving unit Priority is detected over the image quality abnormality of
Further, the printing system is characterized in that the areas are compared so that the entire area of the output image data is made to go around once for every predetermined number of output image data . An image quality adjustment method for an image forming apparatus for forming an image on transfer paper,
An information receiving means for receiving input of transfer sheet identification information;
A document image data obtaining unit obtaining document image data of the image;
A step of forming an image of the original image data on the transfer paper by applying the control value of the image forming process associated with the transfer sheet identification information received by the information receiving means to the image forming process; When,
An output image data generating means for optically reading an image formed on the transfer paper and generating output image data ;
A printed matter inspecting unit that compares the document image data with the output image data for each page of output image data , and detects an image quality abnormality of the output image data;
When the image quality abnormality of the output image data is detected, the correction value creating means creates the control value correction value for reducing the image quality abnormality based on the content and degree of the image quality abnormality, and associates it with the transfer sheet identification information. Storing in the storage means;
When the correction value is associated with the transfer sheet identification information received by the information receiving unit, the image forming unit applies the control value corrected by the correction value to the image forming process to transfer the transfer sheet. anda step for forming an image of the original image data to,
The printed matter inspection unit divides the document image data and the output image data into a plurality of regions having the same number and shape, respectively, and compares only a part of the plurality of regions to detect an image quality abnormality in the output image data. Is what
In the image quality abnormality table in which the type of image quality abnormality that is likely to occur on the transfer paper is associated with the transfer paper identification information, the image quality abnormality associated with the transfer paper identification information received by the information receiving unit Priority is detected over the image quality abnormality of
Further, the image quality adjustment method is characterized in that the regions are compared so that the entire region of the output image data is rotated once for each predetermined number of output image data .