JP2005205695A - Controller, control method and control program for imaging device or inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for an imaging device by which a cleaning failure of the imaging device can be certainly detected in an appropriate detection time. <P>SOLUTION: The control method comprises a step S10 to receive an impediment occurrence signal to be outputted from the imaging device when a fault occurs in the device; a step S14 to acquire printing results image data which are read from the printing results of an image formed on a sheet in the imaging device; and a step S18 and a step S20 to decide if a defect is present in the printing results image data acquired in the step 14. When the fault occurrence signal is received and is not received in the step S10, the processing to detect the defect in the step 18 and the step 20 is switched to detect the defect. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control device, a control method, and a control program for detecting a defect in an image formed by an image forming apparatus.

  It is important to determine whether or not a print result image printed on a sheet in an image forming apparatus such as a copying machine, a digital multifunction peripheral, or a printer is defective.

  As shown in FIG. 9, the electrophotographic image forming apparatus includes a static eliminating unit 12 that neutralizes the photosensitive member 10 in order to remove unnecessary toner remaining on the photosensitive member 10 after the toner is transferred to a sheet, and a photosensitive member. A cleaning unit including a cleaning brush 14 and a cleaning blade 16 that mechanically removes toner remaining in the toner 10 and a toner collection container 18 that collects toner removed from the photoreceptor 10 is provided.

  When a failure such as a paper jam occurs in the image forming apparatus, cleaning is insufficient in a print job immediately after recovery, and unnecessary toner often remains on the photoreceptor 10. As a result, the remaining toner is transferred when the toner is transferred to the sheet next time, and a defect occurs on the sheet. Such disturbance of the image due to a cleaning defect significantly impairs the quality of the print result image. Accordingly, it is necessary to accurately detect the defect and perform a disposal process or the like as necessary. On the other hand, if a highly accurate detection process is performed in order to detect defects reliably, the printing time is extended and the printing cost is increased. Therefore, it is necessary to avoid always performing highly accurate processing.

  Conventionally, a test pattern for finding a defect (image defect) is printed on a white plain paper or the like, and a printed defect is found by a person visually observing the printed test pattern.

  In addition, a halftone chart having a uniform gray brightness is printed as an inspection chart, and the print result of the inspection chart is read by a line sensor, and low contrast white and black colors appearing in the print result image are displayed. A technique for detecting a streak-like defect is disclosed (Japanese Patent Laid-Open No. 6-148096).

  Also disclosed is a technique for detecting a defect based on a stain distribution density obtained by reading a print result image from paper using a camera, detecting a stain candidate from the print result image data, and counting the number of candidates. (JP-A-6-168316).

Japanese Patent Laid-Open No. 6-148096 JP-A-6-168316

  However, in the above prior art, defect detection processing is always performed with a constant detection accuracy regardless of whether or not a failure has occurred in a print job. For this reason, when the defect detection accuracy is set to be low, there is a high possibility that a defect due to a failure occurring during the print job is missed. On the other hand, if the accuracy of defect detection is always increased in order to ensure defect detection, the defect detection process takes time, the time required for the entire print job becomes longer, and printing costs increase. It was happening.

  In view of the above-described problems of the prior art, the present invention provides a control device, a control method, and a control method capable of reliably detecting a cleaning defect in an image forming apparatus in an appropriate detection time in order to solve at least one of the above-described problems. An object is to provide a control program.

  The present invention is a control device for an image forming apparatus, comprising: a printing unit that supplies a coloring material to a sheet; and a transmission unit that transmits a failure occurrence signal when a failure occurs during image formation processing. Receiving means for receiving the generated signal; image data acquiring means for acquiring print result image data read from a printing result formed on the paper in the image forming apparatus; and printing acquired by the image data acquiring means Defect determination means for determining whether or not a defect exists in the result image data, and detection of the defect in the defect determination means in the case where the failure occurrence signal is received and not received in the reception means A defect is detected by changing the process.

  Here, it is preferable to change the processing in the defect determination means in accordance with the type of the failure occurrence signal. For example, when the failure occurrence signal is a signal indicating that a paper jam failure has occurred in the image forming apparatus, it is preferable to detect the defect by changing the defect detection accuracy in the defect determination unit. Furthermore, it is preferable that the processing in the defect determination unit is changed according to the density of the image included in the print result image data acquired in the image data acquisition unit.

  According to another aspect of the present invention, there is provided a control method for an image forming apparatus, the receiving step of receiving a failure occurrence signal output from the image forming apparatus when a failure occurs in the image forming apparatus, An image data acquisition step of acquiring print result image data read from a print result of image formation on paper in an image forming apparatus, and whether or not a defect exists in the print result image data acquired in the image data acquisition step A defect determination step for determining whether or not the failure occurrence signal is received and not received in the reception step, and the defect detection process in the defect determination step is changed to detect the defect. It is characterized by that.

  Here, it is preferable to change the processing in the defect determination step in accordance with the type of the failure occurrence signal. For example, when the failure occurrence signal is a signal indicating that a paper jam failure has occurred in the image forming apparatus, it is preferable to detect the defect by changing the defect detection accuracy in the defect determination step. Furthermore, it is also preferable to change the processing in the defect determination step in accordance with the density of the image included in the print result image data acquired in the image data acquisition step.

  According to another aspect of the present invention, there is provided a control program for an image forming apparatus, comprising: a printing unit that supplies a coloring material to a sheet; and a transmission unit that transmits a failure occurrence signal when a failure occurs during image formation processing. The computer includes a receiving unit that receives the failure occurrence signal, an image data acquiring unit that acquires print result image data read from a print result formed on a sheet in the image forming apparatus, and A defect determination unit that determines whether or not a defect exists in the print result image data acquired by the image data acquisition unit, and when the failure occurrence signal is received or not received by the reception unit As a control device for detecting defects by changing the defect detection process in the defect determination means It characterized in that to ability.

  Here, it is preferable to change the processing in the defect determination means according to the type of the failure occurrence signal. For example, when the failure occurrence signal is a signal indicating that a paper jam failure has occurred in the image forming apparatus, it is preferable to detect the defect by changing the defect detection accuracy in the defect determination unit. It is also preferable to change the processing in the defect determination unit according to the density of the image included in the print result image data acquired in the image data acquisition unit.

  According to the present invention, it is possible to appropriately detect the cleaning defect in the image forming apparatus without unnecessarily lengthening the defect detection time.

  As shown in FIG. 1, the image forming system according to the embodiment of the present invention includes a control device 100, an image forming device 200, and an inspection device 300. The control device 100, the image forming device 200, and the inspection device 300 are connected to be able to transmit information to each other according to a predetermined protocol via an information transmission medium such as a network.

  The image forming apparatus 200 employs an electrophotographic system and can be configured to include a control unit 201, document image data acquisition unit 202, paper feeding unit 203, printing unit 204, paper discharge unit 205, and data interface 206.

  In the present embodiment, the document image data acquisition unit 202 includes a platen 222 and a scanner 224, the paper supply unit 203 includes a paper stocker 230 and a paper transport belt 232, and the printing unit 204 includes the photoconductor 10, the charging unit 240, and the exposure. The sheet discharge unit 205 includes a sheet discharge stocker 250. The sheet discharge unit 205 includes a unit 241, a development unit 242, a transfer unit 244, a fixing unit 245, and a cleaning unit 246. The image forming apparatus 200 shown in FIG. 1 is intended for color printing and corresponds to each color component in the CMYK color space represented by cyan (C), magenta (M), yellow (Y), and black (K). The photosensitive member 10, the charging unit 240, the exposure unit 241, the developing unit 242, the transfer unit 244, and the cleaning unit 246 are provided.

  The document image data acquisition unit 202 reads a document image from a document placed on the platen 222, digitizes the read document image, and sends it to the control unit 201 as document image data. The read document image data is transmitted to the control apparatus 100 via the network as needed using the data interface 206. The document image data may be received from an external computer or the like via the network using the data interface 206. For example, it is preferable that the control device 100 also serves as a computer that is a transmission source of document image data. The received document image data is temporarily stored in a buffer memory included in the control unit 201.

  Alternatively, the document image data may be stored and stored in the image forming apparatus 200, and the document image data to be printed may be specified by transmitting specific information from the control apparatus 100 using the data interface 260. The specific information refers to information used to specify original image data to be printed in the image forming apparatus 200.

  For example, as shown in FIG. 2, when a unique identification number is assigned to each original image data and stored in the buffer memory of the control unit 201, the specific information is assigned to the original image data to be printed. Identification number. In the example of FIG. 2, if the document image data to be printed is file A, the specific information is an identification number 001.

  The specific information may be original image data itself to be printed. That is, document image data may be stored and stored in the control device 100, the document image data to be printed may be transmitted from the control device 100 to the image forming device 200, and the document image data may be the print target.

  The paper feeding unit 203 transports paper necessary for printing from the paper stocker 230 to the printing unit 204 and the paper discharge unit 205 by the paper transport belt 232. The direction along the carrying direction is called a sub-scanning line, and the direction perpendicular to the carrying direction is called a main scanning direction.

  The control unit 201 transmits the document image data to be printed specified by the specific information to the printing unit 204. The printing unit 204 prints document image data received from the control unit 201 on a sheet. The charging unit 240, the exposure unit 241, the developing unit 242, the transfer unit 244, and the cleaning unit 246 are arranged around the cylindrical photoconductor 10, and the photoconductor 10 is rotated at a predetermined cycle about its central axis. After charging the photosensitive member 243 by the charging unit 240, the exposure unit 241 forms document image data on the surface of the photosensitive member 243 as a latent image, the developing unit 242 attaches toner to the latent image on the photosensitive member, and the transfer unit 244. By transferring the toner onto the paper, original image data is formed on the paper as an actual image. The sheet on which the toner is transferred is sent to the fixing unit 245, and the toner is fixed on the sheet by heating. In the paper discharge unit 205, the paper printed by the printing unit 204 is discharged to the paper discharge stocker 250.

  As shown in FIG. 9, the cleaning unit 246 is removed from the neutralization unit 12 that neutralizes the photoconductor 10, the cleaning brush 14 that mechanically removes toner remaining on the photoconductor 10, the cleaning blade 16, and the photoconductor 10. And a toner collecting container 18 for collecting the toner. The neutralization unit 12 neutralizes the potential of the surface of the photoconductor 10 so that the toner electrostatically attached to the surface of the photoconductor 10 is easily removed. The cleaning brush 14 and the cleaning blade 16 mechanically remove the discharged toner from the surface of the photoreceptor 10. The removed toner is collected in the toner collection container 18.

  Sensors for transmitting a control signal to the control unit 201 to inform the paper supply unit 203, the printing unit 204, and the paper discharge unit 205 of the image forming apparatus 200 when a problem occurs during a print job. Etc. are provided. In response to the control signal, the control unit 201 transmits a failure occurrence signal indicating that a failure has occurred during the image forming process in the image forming apparatus 200 to the control device 100. The failure occurrence signal is transmitted to the control device 100 via the network using the data interface 206. For example, when a paper jam occurs in the process of conveying a paper, a control signal notifying the paper jam is transmitted to the control unit 201. When the control unit 201 receives the control signal notifying the paper jam, the control unit 201 transmits a paper jam occurrence signal to the control unit 100. Here, the failure occurrence signal is not limited to the paper jam occurrence signal, and any failure that affects the image forming process in the image forming apparatus 200 when recovered from the failure can be targeted. The failure that affects the image forming process specifically refers to a failure that causes a defect in a print result image printed on paper. More specifically, there are problems in the latent image forming process, developing process, transfer process, and fixing process in the printing unit 204, problems in cleaning the printing unit, problems in acquiring document image data, and the like.

  In this embodiment, the paper means not only general paper but also general objects to be printed including OHP sheets, cardboard, and postcards.

  The inspection apparatus 300 is used in combination with the image forming apparatus 200, and has a function of reading a print result image on a sheet at a later stage than the printing unit 204 of the image forming apparatus 200 and outputting the print result image data to the control apparatus 100 as print result image data. . The inspection apparatus 300 can be configured to include an image reading unit 301 and a data interface 302.

  The image reading unit 301 can include a lamp serving as a light source, a line sensor including a photoelectric conversion element, and an analog / digital converter. A printed image is read from the entire sheet by illuminating the sheet conveyed by the conveyance belt 232 with a lamp and photoelectrically converting light reflected from the sheet by a line sensor. The read print result image is sent to an analog / digital converter and converted into a digital signal. The digitized print result image data is sent to the control device 100 via the network using the data interface 302.

  As shown in FIG. 3, the control device 100 includes a control unit 20, a storage unit 22, a data interface 24, and a user interface 26. The control unit 20 corresponds to a CPU of the computer, and controls the control device 100 in an integrated manner by executing a print control program. The storage unit 22 includes a semiconductor memory, and stores and saves electronic information such as programs processed by the control unit 20, image data, and correction conditions. When a large amount of data is stored and held, it is also preferable to use a mass storage device such as a hard disk device, a magnetic tape device, a magnetic disk device, an optical disk device, or a magneto-optical disk device as an auxiliary storage device. The data interface 24 is connected to the data interface 206 in the image forming apparatus 200 and the data interface 302 in the inspection apparatus 300 via a network so as to be able to transmit information, and is used to transmit / receive specific information, document image data, or print result image data. It is done. The user interface 26 includes an input / output device such as a touch panel, and is used for receiving an instruction from the user to the control device 100 and presenting information to the user from the control device 100.

  The control device 100 has a function of detecting a defect from print result image data received from the inspection device 300 and controlling the image forming device 200 based on the detection result. At this time, a failure occurrence signal is received from the image forming apparatus 200, and processing is performed according to the failure occurrence signal.

  FIG. 4 shows a flowchart of a print control method performed by the control apparatus 100. Each step of the printing control method is converted into a printing control program that can be processed by a computer, and stored and held in the storage unit 22. The control unit 20 reads the print control program held in the storage unit 22 and sequentially executes each process. In the present invention, each step is not an essential requirement, and can be executed in appropriate combination.

  In step S <b> 10, it is determined whether a failure occurrence signal is generated from the image forming apparatus 200. In the control apparatus 100, this process functions as a failure occurrence signal confirmation unit and a reception unit. The control unit 20 uses the data interface 24 to check whether a failure occurrence signal is transmitted from the image forming apparatus 200. If a failure occurrence signal is transmitted, the failure occurrence signal is received, and the content of the failure occurrence signal is temporarily stored and held in the storage unit 22. For example, when a paper jam occurs in the process of transporting paper in the image forming apparatus 200, a paper jam occurrence signal is received. The control unit 20 waits for processing until the failure occurrence signal is stopped. If the failure occurrence signal has not been transmitted, the process proceeds to step S12 as it is.

  In step S <b> 12, the document image data identification information is transmitted from the control device 100 to the image forming apparatus 200. In the control device 100, this process functions as document image data specifying means. The control unit 20 selects specific information for specifying original image data to be printed based on a user command from the user interface 26 or the like. The specific information is transmitted to the image forming apparatus 200 via the network using the data interface 24.

  The image forming apparatus 200 receives this specific information using the data interface 206. The control unit 201 forms an image on a sheet in the printing unit 204 based on the document image data to be printed. The inspection apparatus 300 reads the print result image printed from the paper and transmits it to the control apparatus 100 using the data interface 302.

  In step S <b> 14, print result image data is acquired from the inspection apparatus 300. In the control device 100, this step functions as an image data acquisition unit. The control unit 20 receives print result image data via the network using the data interface 24. The received print result image data is temporarily stored and held in the storage unit 22. The storage unit 22 holds at least two or more print result image data read from the print result images of the previous image formation process and the current image formation process.

  In step S <b> 16, it is determined whether a failure occurrence signal has been acquired from the image forming apparatus 200. In the control device 100, this step functions as a failure occurrence signal determination unit. The controller 20 checks whether or not a failure occurrence signal has been received in step S10. If a failure occurrence signal has not been received, the process proceeds to step S18. If a failure occurrence signal is received, the process proceeds to step S20.

  In step S18, a normal defect extraction process is performed. In the control device 100, this process normally functions as a defect extraction means. In step S14, the control unit 20 performs simple defect extraction processing from the print result image data received this time. For example, the density difference of each color component for each pixel is calculated from the entire area of the original image data specified as the print target in step S12 and the entire area of the print result image data received this time in step S14. If a difference greater than or equal to the difference threshold is found in an area greater than or equal to a predetermined size threshold, the defect is processed as being present. When the defect extraction process ends, the process proceeds to step S22.

  In step S20, a highly accurate defect extraction process is performed. In the control device 100, this process functions as a high-precision defect extraction means. The control unit 20 extracts defects using a method that can extract defects with higher accuracy than the normal defect extraction process performed in step S16. The defect extraction process is preferably performed by a different method depending on the type of the failure occurrence signal received in step S18.

  When the process is changed according to the type of the fault occurrence signal, it is preferable to select the defect detection process according to the type of fault that generates a defect having a different form. For example, if the failure occurrence signal is a paper jam occurrence signal, a defect due to a cleaning failure is likely to occur in image formation immediately after the paper jam has occurred. Is preferably performed. Specifically, processing can be performed according to a subroutine shown in FIG.

  In step S20-1, it is determined whether or not a high density area exists in the previous print result image data. In the control device 100, this process functions as a high concentration area extracting means. The control unit 20 reads the print result image data 50 received in the previous step S14 from the storage unit 22, and, as shown in FIG. A region 30 is detected. For example, a density threshold value determined as high density is set to 80% or more of the maximum density in the image forming apparatus 200, and an area having a density equal to or higher than the density threshold value can be detected as the high density area 30. Here, when the image forming apparatus 200 is a color printing machine using a plurality of colors such as cyan (C), magenta (M), yellow (Y), and black (K) as in the present embodiment, It is preferable to detect the high density region 30 for each color component.

  Here, processing when forming an image of the high density region 30 will be described. For example, as shown in FIG. 7A, a latent image 32 corresponding to the high density region 30 included in the document image data is formed on the surface of the photoreceptor 10. A high density toner 34 is attached to the latent image 32 in the developing unit 242. Then, as shown in FIG. 7B, the toner 34 is transferred to the paper 40 in the transfer unit 244. At that time, a large amount of the toner 34 that has not been completely transferred remains on the surface of the photoreceptor 10 in the region 36 corresponding to the high density region. Subsequently, the region 36 reaches the cleaning unit 246, and the remaining toner 34 is cleaned. If the cleaning unit 246 has a defect such as wear of the cleaning brush 14 or the cleaning blade 16, a large amount of toner 34 that cannot be removed remains in the region 36 of the photoconductor 10 even after cleaning. As a result, as shown in FIG. 7C, the toner remaining in the region 36 of the photoconductor 10 at the timing when the high density region 30 is transferred onto the paper 40 and rotated by an integral multiple of the rotation period T of the photoconductor 10. 34 is transferred to the paper 40 and causes defects on the paper.

  For example, when a rectangular high density area 30 exists in the print result image data 50 received last time as shown in FIG. 6, the high density area in the print result image data 52 received this time as shown in FIG. Defects due to poor cleaning occur in the areas 42a, 42b,... Printed at the timing when the photosensitive member 10 is rotated by an integral multiple of the rotation period T from the position where 30 is printed.

  In step S20-2, it is determined whether or not a high density region exists. In the control device 100, this process functions as a high-concentration area determination unit. If there is no high density region 30 that is equal to or higher than the density threshold from the previous print result image data in step S20-1, the control unit 20 exits the subroutine and shifts the process to step S18. If the high density region 30 exists, the process proceeds to step S20-3.

  In step S20-3, a region for detecting a defect is determined. In the control device 100, this step functions as a detection target region determination unit. The control unit 20 reads the print result image data received this time from the storage unit 22 in step S14, and the photoconductor 10 is an integral multiple of the rotation period T from the position of the high density region 30 extracted in step S20-1. The image area areas 42a, 42b,... Formed with the rotation timing are determined as defect detection target areas.

  For example, as shown in FIG. 8, when a rectangular high density region 30 is extracted in step S14, if the photosensitive member 10 has a peripheral length L, the peripheral length nL (n The area printed after (integer of 1 or more) is set as the defect detection target area 32. At this time, as shown in FIG. 8, it is preferable to determine the defect detection target areas 42a, 42b... In consideration of the sheet conveyance interval A when the sheet is conveyed in the image forming apparatus 200. As described above, the defect detection areas 42a, 42b,... That are likely to cause defects corresponding to the high density area 30 can be correctly determined by considering the sheet conveyance interval A.

  In step S20-4, a defect is extracted from the defect detection target area. In the control device 100, this process functions as a defect extraction means. The control unit 20 investigates whether or not a defect has occurred in the defect detection target areas 42a, 42b... Determined in step S18. The control unit 20 reads the print result image data 52 received this time in step S14 from the storage unit 22, and from the original image data specified as the print target in step S12 and the print result image data 52 received this time in step S14. The density difference of each color component in each pixel is calculated, and a defect exists when there is a pixel having a difference equal to or greater than a predetermined difference threshold in the difference data of the defect detection target areas 42a, 42b. Can do. At this time, the difference threshold used in step S20-4 is preferably set to a value smaller than the difference threshold used in step S18. This makes it possible to detect a defect with higher accuracy than the normal defect extraction process in step S18.

  It is also preferable to determine that the defect is caused by a cleaning defect only when a defect exists in a plurality of defect detection target areas. By confirming defects in a plurality of areas synchronized with the printing cycle of the printing unit, it is possible to more accurately identify that the defect has occurred due to defective cleaning.

  Further, it is preferable to determine whether or not a defect exists from a defect detection area where printing is performed earliest after a paper jam occurs. This is because defects that occur each time the rotational speed of the photoconductor 10 increases after printing the high density region 30 are weakened, and it becomes difficult to detect defects caused by poor cleaning.

  However, the defect detection method in the present embodiment is not limited to this, and other image processing methods may be used according to the type of the failure occurrence signal received in step S10. When the process is finished, the control unit 20 shifts the process to step S22 of the main routine.

  In step S22, it is determined whether or not the defect has been extracted. In the control apparatus 100, this process is combined with step S18 or step S20 and functions as a defect determination means. If a defect is extracted in step S18 or step S20, the process proceeds to step S24. On the other hand, if no defect exists, the process returns to step S10 to perform a new print job.

  In step S24, a control process according to the defect detection result is performed. In the control device 100, this process functions as a defect handling processing means. At this time, different processing may be performed depending on whether the defect is extracted by the normal defect extraction processing in step S18 or whether the defect is extracted by the high-precision defect extraction processing in step S20. It is also preferable to perform different processing depending on the type of failure occurrence signal received in step S10. For example, when a paper jam occurrence signal is received in step S10 and a defect exists, a process for displaying a screen prompting the user to confirm the cleaning unit 246 on the display device of the user interface 26 may be performed. it can. In step S10, when a fault occurrence signal indicating a fault in the image forming process such as a latent image forming process, a developing process, a transfer process, and a fixing process is received and a defect exists, each part of the image forming apparatus 200 is checked. A screen requesting repair may be presented.

  As described above, according to the present embodiment, a normal simple inspection process is performed while a failure has not occurred in a print job, and after the failure has occurred and the print job has been recovered, the accuracy is higher. Inspection processing can be performed. Thereby, the inspection time in the whole print job can be shortened. Furthermore, it is possible to detect a defect with high accuracy as necessary, thereby preventing the defect from being overlooked.

  In particular, when a paper jam occurs in the image forming apparatus 200, an area where an image is formed at a high density is obtained from the print result image data, and the photoconductor 10 rotates by an integral multiple of the rotation period from the position of the high density area. By confirming the contamination at the position where the transfer is performed at the same timing, it is possible to reliably detect a cleaning defect. That is, it becomes possible to accurately detect a cleaning defect that is highly likely to occur due to a paper jam. In addition, when a region having a high density is not included in the printing result image before the paper jam occurs, a defect due to a cleaning defect is difficult to occur, so that a normal defect detection process can be performed.

  In this embodiment, the electrophotographic image forming apparatus 200 having the drum-shaped photoconductor 10 has been described. However, the scope of application of the present invention is not limited to this.

  For example, a method for extracting a defect caused by defective cleaning is intended for an image forming apparatus having a component that supplies a color developing material such as toner or ink to a sheet at a predetermined cycle and a cleaning unit that cleans the component. It can be. That is, an image that requires a large amount of cleaning, for example, an image area that consumes a large amount of ink in an ink jet printer, is detected from the print result image data, and an integral multiple of the period in which the printing unit supplies the coloring material from the position of the image area By determining whether or not there is a defect in a region where an image is formed later, it is possible to determine whether or not a defect has occurred in cleaning.

  The image forming apparatus may be an electrophotographic system using a rotating intermediate transfer belt. In this case, a latent image is formed on the surface of the intermediate transfer body belt, the latent image is developed with a high density toner, and the high density area is transferred from the intermediate transfer body belt to the sheet. After the high density area is cleaned by the cleaning unit, the defect is applied to the area where the transfer is performed at the position (timing) where the intermediate transfer belt is rotated by an integral multiple of the rotation period from the position (timing) where the high density area is transferred. By determining whether or not there is a defect, it is possible to check whether or not a defect has occurred in the cleaning unit. At this time, the sheet on which the test pattern is transferred may be different from the sheet having a defect detection area.

  In the present embodiment, a high density region is detected from print result image data obtained by reading a print result image printed on paper, and a defect detection target region corresponding to the position is determined. However, a high density area may be detected from the original image data, and the defect detection area may be obtained from the print result image data read from the print result image based on the original image data. In this case, a region where an image is formed after an integral multiple of the period in which the printing means supplies the coloring material from the position of the high density region may be determined as the defect detection target region.

1 is a diagram showing a configuration of an image forming system in an embodiment of the present invention. It is a figure which shows the database with which the specific information which specifies original image data was registered. 1 is a block diagram illustrating a configuration of a print control apparatus according to an embodiment of the present invention. It is a figure which shows the flowchart of the printing control method in embodiment of this invention. It is a figure which shows the subroutine of the extraction method of the defect in embodiment of this invention. It is a figure which shows the example of the high concentration area | region detected in embodiment of this invention. It is a figure explaining generation | occurrence | production of the defect by the defect of the cleaning in embodiment of this invention. It is a figure which shows the example of the defect detection object area | region in embodiment of this invention. FIG. 2 is a diagram illustrating a configuration of a cleaning unit in an electrophotographic image forming apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Photoconductor, 12 Static elimination part, 14 Cleaning brush, 16 Cleaning blade, 18 Toner collection container, 20 Control part, 22 Storage part, 24 Data interface, 26 User interface, 30 High density area, 32 Latent image, 34 Toner, 36 High density toner area, 40 sheets, 42a, 42b image area, 100 printing control apparatus, 200 image forming apparatus, 201 control unit, 202 original image data acquisition means, 203 paper feeding means, 204 printing means, 205 paper discharge means, 206 Data Interface, 222 Platen, 224 Scanner, 230 Paper Stocker, 232 Conveyor Belt, 232 Paper Conveyor Belt, 240 Charging Unit, 241 Exposure Unit, 242 Development Unit, 243 Photoconductor, 244 Transfer Unit, 245 Fixing Unit, 246 Cree Ning unit, 250 paper discharge stocker, 260 data interface, 300 inspection device, 301 image reading means, 302 data interface.

Claims (12)

A control device for an image forming apparatus, comprising: a printing unit that supplies a coloring material to a sheet; and a transmission unit that transmits a failure occurrence signal when a failure occurs during image formation processing,
Receiving means for receiving the failure occurrence signal;
Image data acquisition means for acquiring print result image data read from a print result formed on a sheet in the image forming apparatus;
Defect determination means for determining whether or not there is a defect in the print result image data acquired by the image data acquisition means,
2. A control apparatus, comprising: detecting a defect by changing a defect detection process in the defect determination unit when the failure occurrence signal is received and not received in the reception unit. The control device according to claim 1,
A control apparatus characterized in that processing in the defect determination means is changed in accordance with the type of the failure occurrence signal. The control device according to claim 2,
A control device, wherein when a failure occurrence signal is a signal indicating that a paper jam failure has occurred in the image forming apparatus, the defect detection accuracy in the defect determination means is changed to detect a defect. In the control device according to any one of claims 1 to 3,
The control apparatus characterized by changing the process in the said defect determination means according to the density of the image contained in the printing result image data acquired in the said image data acquisition means. An image forming apparatus control method comprising:
A receiving step of receiving a fault occurrence signal output from the image forming apparatus when a fault occurs in the image forming apparatus;
An image data acquisition step of acquiring print result image data read from a print result formed on a sheet in the image forming apparatus;
A defect determination step of determining whether or not a defect exists in the print result image data acquired in the image data acquisition step,
A control method comprising: detecting a defect by changing a defect detection process in the defect determination step when the failure occurrence signal is received or not received in the reception step. The control method according to claim 5, wherein
A control method comprising: changing processing in the defect determination step according to a type of the failure occurrence signal. The control method according to claim 6,
A control method comprising: detecting defect by changing defect detection accuracy in the defect determination step when the failure occurrence signal is a signal indicating that a paper jam failure has occurred in the image forming apparatus. In the control method according to any one of claims 5 to 7,
A control device that changes processing in the defect determination step in accordance with the density of an image included in the print result image data acquired in the image data acquisition step. A control program for an image forming apparatus, comprising: a printing unit that supplies a coloring material to a sheet; and a transmission unit that transmits a failure occurrence signal when a failure occurs during image formation processing,
Computer
Receiving means for receiving the failure occurrence signal;
Image data acquisition means for acquiring print result image data read from a print result formed on a sheet in the image forming apparatus;
Defect determination means for determining whether or not there is a defect in the print result image data acquired by the image data acquisition means,
A control program that functions as a control device that detects a defect by changing a defect detection process in the defect determination unit when the failure occurrence signal is received or not received by the reception unit. . The control program according to claim 9,
A control program that changes processing in the defect determination means in accordance with a type of the failure occurrence signal. The control program according to claim 10,
A control program for detecting a defect by changing a defect detection accuracy in the defect determination means when the failure occurrence signal is a signal indicating that a paper jam failure has occurred in the image forming apparatus. In the control program according to any one of claims 9 to 11,
A control program that changes processing in the defect determination unit in accordance with the density of an image included in print result image data acquired in the image data acquisition unit.

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