JP2017058424A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the capacity of a storage part used for image formation by efficiently and simply controlling input/output of data to/from the storage part.SOLUTION: There is provided an image forming apparatus 10 that writes image data corresponding to pages in storage areas of an output memory 25 in page order and reads the image data in circulation to form images, where when a sheet is determined to be normal in an image inspection by an image inspection part 13, the image forming apparatus deletes image data corresponding to the sheet determined to be normal from the storage area and writes image data corresponding to a page to be subsequently formed into an image in a storage area from which the image data is deleted, and when a sheet is determined to be abnormal by the image inspection part 13, at the subsequent reading order from a storage area where image data corresponding to the sheet determined to be abnormal, forms an image again on the basis of the image data stored in the storage area.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an image forming apparatus.

  Conventionally, in an image forming apparatus, an image reading unit arranged on a paper conveyance path after image formation is used to read an image on a sheet and inspect whether there is an abnormality such as an image density defect, color misregistration, and dirt. Is being used.

  For example, when sheet information is read from a sheet on which an image is recorded, and the read information is determined to be NG, a sheet that has already been fed following the sheet determined to be NG is temporarily stacked. A sheet inspection apparatus that records an image on a sheet that replaces the NG sheet and inserts a re-recorded sheet in front of the stacked sheets is disclosed (see Patent Document 1).

  Incidentally, in the image forming apparatus, an image output memory (hereinafter referred to as an output memory) for storing image data immediately before image formation is used in order to match the output of the image data with the image writing timing. If it is determined that there is an abnormality in the image inspection, it is necessary to form an image again. Therefore, the image data corresponding to the image determined to be abnormal must be held in the output memory.

JP 2004-106999 A

  However, there is a demand for the capacity of the output memory to be kept as small as possible, and since usually only a few pages are prepared, efficient memory control is required. In addition, there is a problem that the processing load increases when the control of data input / output to / from the output memory becomes complicated. In Patent Document 1, there is no mention of a memory control method for efficiently regenerating an image determined to be abnormal with limited memory resources.

  The present invention has been made in view of the above problems in the prior art, and suppresses the capacity of the storage unit by efficiently and simply controlling the input and output of data to and from the storage unit used for image formation. Is an issue.

  In order to solve the above-mentioned problem, the invention according to claim 1 inspects an image forming unit that forms an image on a sheet and an image on the sheet formed by the image forming unit, and the image is normal. An image inspection unit for determining whether there is a storage unit, a storage unit which has a plurality of storage areas and can circulate data from the plurality of storage areas, and stores the image data corresponding to each page in page order A control unit that writes to each storage area of the copy unit, reads the image data from each storage area of the storage unit in a circulating manner, and causes the image forming unit to form an image based on the read image data. In the image forming apparatus, the control unit stores image data corresponding to the paper determined to be normal when the image inspection unit determines that the image is normal. Storage area The image data corresponding to the next page to be image-formed is written in the storage area from which the image data has been deleted, and the image inspection unit determines that there is an abnormality next time. When the reading order from the storage area in which the image data corresponding to the paper determined to be stored comes around, an image is formed again in the image forming unit based on the image data stored in the storage area Let

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the number of storage areas of the storage unit is determined by the image forming unit along the sheet conveyance path of the image forming apparatus. Is the same as the number of image data corresponding to the sheet existing from the start to the determination by the image inspection unit.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the control unit is determined to be normal when it is determined normal by the image inspection unit. The paper is discharged to the first paper discharge tray, and when the image inspection unit determines that the paper is abnormal, the paper determined to be abnormal is discharged to the second paper discharge tray.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the control unit is a sheet in the middle of image formation by the image forming unit when determined to be abnormal by the image inspection unit, Alternatively, when the image has been formed by the image forming unit and before being inspected by the image inspection unit, the paper that has been determined to be normal is temporarily stored in the stacker. store.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the control unit is normal when the image formed again by the image inspection unit is determined to be normal. Is discharged to the first paper discharge tray, and then the paper temporarily stored in the stacker is discharged to the first paper discharge tray in the order of entering the stacker.

  According to the present invention, the capacity of the storage unit can be suppressed by efficiently and simply controlling the input and output of data to and from the storage unit used for image formation.

1 is a schematic configuration diagram of an image forming apparatus in an embodiment of the present invention. 2 is a block diagram illustrating a functional configuration of the image forming apparatus. FIG. It is a figure for demonstrating writing of the image data with respect to an output memory, and reading of the image data from an output memory. It is a flowchart which shows the transfer process to an output memory. It is a flowchart which shows the output control process of an output memory. It is a flowchart which shows a conveyance destination determination process. It is a flowchart which shows the discharge process from a stacker. (A) is a diagram showing the transport position of each sheet when the image inspection of the third page is completed. (B) is a schematic diagram showing the states of the output memory and the main memory when the image inspection for the third page is completed. (A) is a diagram showing the transport position of each sheet when the image inspection of the fourth page is completed. (B) is a schematic diagram showing the states of the output memory and the main memory when the image inspection for the fourth page is completed. (A) is a diagram showing the transport position of each sheet when the image inspection of the fifth page is completed. (B) is a schematic diagram showing the state of the output memory and the main memory when the image inspection for the fifth page is completed. (A) is a diagram showing the transport position of each sheet when the image inspection of the re-formed third page is completed. (B) is a schematic diagram showing the state of the output memory and the main memory when the image inspection of the re-formed third page is completed. (A) is a figure which shows the conveyance position of each paper when the image inspection of the 6th page is completed. (B) is a schematic diagram showing the states of the output memory and the main memory when the image inspection for the sixth page is completed. (A) is a figure which shows the conveyance position of each paper when the image inspection of the 7th page is completed. (B) is a schematic diagram showing the states of the output memory and the main memory when the image inspection for the seventh page is completed.

  Embodiments of an image forming apparatus according to the present invention will be described below with reference to the drawings. The present invention is not limited to the illustrated example.

FIG. 1 is a schematic configuration diagram of the image forming apparatus 10.
The image forming apparatus 10 is an image forming apparatus that forms an image by electrophotography based on image data received from an external device or image data obtained by scanning a document.
The image forming apparatus 10 includes a paper feeding unit 11, an image forming unit 12, an image inspection unit 13, a path changing unit 14, a normal path 15, a stacker 16, a path changing unit 17, a paper discharge unit 18, and the like.

  The paper feed unit 11 includes a plurality of paper feed trays and supplies paper to the image forming unit 12. Each paper feed tray stores paper of a paper type and size predetermined for each paper feed tray.

The image forming unit 12 forms an image on the paper supplied from the paper supply unit 11.
The image forming unit 12 includes a photosensitive drum 121, a fixing unit 122, and the like. The photosensitive drum 121 is uniformly charged and then scanned and exposed with a laser beam based on the image data to form an electrostatic latent image. Then, toner is attached to the electrostatic latent image on the photosensitive drum 121 and development is performed. The toner image formed on the photosensitive drum 121 is transferred onto the paper, and then heated and pressurized by the fixing unit 122 to be fixed on the paper.

The image inspection unit 13 is provided downstream of the image forming unit 12, inspects an image on a sheet formed by the image forming unit 12, and determines whether or not the image is normal. For example, the image inspection unit 13 determines whether the inspection items are normal or abnormal in inspection items such as an image density defect, color misregistration, dirt, solid white spots, and broken characters.
The image inspection unit 13 includes an image reading unit 131 and the like. The image reading unit 131 includes a line sensor in which a plurality of light receiving elements are arranged at a predetermined interval in a direction orthogonal to the paper transport direction, and reads an image on the paper and generates read data. Each light receiving element outputs a signal corresponding to the intensity of light emitted from the light source and reflected from the surface of the paper. As the line sensor, for example, a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor is used.

  The path changing unit 14 switches the conveyance path of the paper discharged from the image inspection unit 13 to the path R1 or the path R2. When the route R1 is selected, the sheet is conveyed to the normal route 15. On the other hand, when the route R2 is selected, the sheets are accumulated in the stacker 16.

  The normal path 15 is a paper conveyance path provided between the path changing unit 14 and the path changing unit 17. The normal path 15 is used when paper after image inspection is discharged to the paper discharge unit 18 without going through the stacker 16.

  The stacker 16 temporarily accumulates and stores paper. The paper temporarily stored in the stacker 16 is discharged in the order in which it enters the stacker 16.

  The path changing unit 17 discharges the paper that has passed the normal path 15 or the paper stored in the stacker 16 to the paper discharge unit 18. Specifically, the path changing unit 17 switches the paper transport path to the path R3, the path R4, or the path R5. When the path R3 is selected, the sheet that has passed through the normal path 15 is discharged to the waste paper discharge tray T2 as the second discharge tray. When the route R4 is selected, the sheet that has passed through the normal route 15 is discharged to the normal discharge tray T1 as the first discharge tray. When the path R5 is selected, the paper stored in the stacker 16 is discharged to the normal paper discharge tray T1.

An image is formed on the paper discharge unit 18 by the image forming unit 12, and the paper on which the image inspection is performed by the image inspection unit 13 is discharged.
The paper discharge unit 18 includes a normal paper discharge tray T1 and a waste paper discharge tray T2. The paper determined to be normal by the image inspection is discharged to the normal paper discharge tray T1. The paper that has been determined to be abnormal by the image inspection is discharged to the waste paper discharge tray T2.

FIG. 2 is a block diagram illustrating a functional configuration of the image forming apparatus 10.
As shown in FIG. 2, the image forming apparatus 10 includes a paper feeding unit 11, an image forming unit 12, an image inspection unit 13, a stacker 16, a paper discharge unit 18, a CPU (Central Processing Unit) 19, and a ROM (Read Only Memory). 20, a communication unit 21, a transport unit 22, a main memory 23, an output ASIC (Application Specific Integrated Circuit) 24, an output memory 25, and the like. Note that description of the functional units already described is omitted.

  The image inspection unit 13 includes an image reading unit 131, a determination unit 132, and the like. The determination unit 132 determines whether or not the image is normal for each item of the image inspection based on the read data obtained by the image reading unit 131, and outputs the determination result to the CPU 19. The determination unit 132 may be configured by hardware, or may be realized by software processing in cooperation with a program stored in the ROM 20 and the CPU 19.

The CPU 19 reads out various processing programs stored in the ROM 20 and centrally controls the operation of each unit of the image forming apparatus 10 according to the programs.
The ROM 20 is configured by a non-volatile semiconductor memory or the like, and stores various processing programs, parameters and files necessary for executing the programs, and the like.

  The communication unit 21 transmits and receives data to and from an external device connected to a communication network such as a LAN (Local Area Network). For example, the communication unit 21 receives image data that is an image formation target.

  The transport unit 22 includes a transport roller for transporting paper, and supplies the paper stored in the paper feed tray of the paper feed unit 11 to the image forming unit 12, and the paper after image formation is the normal paper discharge tray T <b> 1. Alternatively, the paper is conveyed in the image forming apparatus 10 until it is discharged to the waste paper discharge tray T2. The transport unit 22 includes route changing units 14 and 17 and switches the paper transport route.

  The main memory 23 is a storage device that stores data. The main memory 23 stores image data received from an external device such as a PC (Personal Computer) or image data obtained by scanning a document with a scanner (not shown).

  The output ASIC 24 inputs / outputs data to / from the output memory 25 and adjusts the output timing of image data to the image forming unit 12. During image formation, image data is transferred from the main memory 23 to the output memory 25 via the output ASIC 24. Further, image data is output from the output memory 25 to the image forming unit 12 via the output ASIC 24.

The output memory 25 is an image output memory that stores image data immediately before image formation. The output memory 25 has a plurality of storage areas, and is configured to be able to read data by circulating from the plurality of storage areas.
The output memory 25 stores image data of pages from the page during image formation until the inspection is completed (precisely, it is determined that the inspection is normal). The number of storage areas included in the output memory 25 is the number of sheets existing between the start of image formation by the image forming unit 12 and the determination by the image inspecting unit 13 along the sheet conveyance path of the image forming apparatus 10. It matches the number of corresponding image data. In the example shown in FIG. 1, there are three sheets P1 to P3 in the sheet conveyance path from the start of image formation to the completion of the image inspection determination.

  In the present embodiment, the output memory 25 has three storage areas A, B, and C, and can store image data for three pages. Image data to be image-formed is circulated and output from the output memory 25 in the order of storage area A → storage area B → storage area C → storage area A → storage area B →.

  The CPU 19 writes the image data corresponding to each page stored in the main memory 23 to each storage area of the output memory 25 in the page order, reads the image data from each storage area of the output memory 25, and reads the read data. Based on the image data thus formed, the image forming unit 12 is caused to form an image.

  When the image inspection unit 13 determines that the image is normal, the CPU 19 deletes the image data corresponding to the sheet determined to be normal from the storage area in which the image data is stored, and the image data The image data corresponding to the page to be image-formed next is written (transferred from the main memory 23) to the storage area from which is deleted. The CPU 19 deletes the image data transferred from the main memory 23 to the output memory 25 from the main memory 23.

For example, image data corresponding to the third page is stored in the storage area C of the output memory 25, image data corresponding to the fourth page is stored in the storage area A, and image data corresponding to the fifth page is stored in the storage area B. Is stored, the image inspection is completed for the third page, and the image is being formed for the fourth and fifth pages.
When it is determined to be normal in the image inspection for the third page, the image data corresponding to the third page is deleted from the storage area C of the output memory 25 as shown in FIG. Image data corresponding to the sixth page is transferred from C to the main memory 23.

Next, as shown in FIG. 3B, the image data corresponding to the sixth page stored in the storage area C of the output memory 25 is output to the image forming unit 12, and image formation is started.
Further, when it is determined that the image inspection is normal in the fourth page, the image data corresponding to the fourth page is deleted from the storage area A of the output memory 25, and seven pages from the main memory 23 are stored in the empty storage area A. Image data corresponding to the eyes is transferred.

Next, as shown in FIG. 3C, image data corresponding to the seventh page stored in the storage area A of the output memory 25 is output to the image forming unit 12, and image formation is started.
If it is determined that the image inspection is normal in the fifth page, the image data corresponding to the fifth page is deleted from the storage area B of the output memory 25, and eight pages from the main memory 23 are stored in the empty storage area B. Image data corresponding to the eyes is transferred.

  Next, as shown in FIG. 3D, image data corresponding to the eighth page stored in the storage area B of the output memory 25 is output to the image forming unit 12, and image formation is started.

  When the image inspection unit 13 determines that the image is abnormal, the CPU 19 leaves the image data corresponding to the paper determined to be abnormal in the storage area in which the image data is stored, and the main memory The transfer of the image data from 23 to the storage area is stopped. When the CPU 19 determines that the abnormality is detected by the image inspection unit 13, the next time when the reading order from the storage area in which the image data corresponding to the paper determined to be abnormal next is stored has come. Based on the image data stored in the storage area, the image forming unit 12 forms an image again.

When the image inspection unit 13 determines that the image is normal, the CPU 19 discharges the paper determined to be normal to the normal paper discharge tray T1.
When the image inspection unit 13 determines that there is an abnormality, the CPU 19 causes the paper determined to be abnormal to be discharged to the waste paper discharge tray T2.

  The CPU 19 determines whether the image forming unit 12 is in the process of forming an image when the image inspecting unit 13 determines that the image is abnormal, or has been formed by the image forming unit 12 and has not been inspected by the image inspecting unit 13. When the image inspection unit 13 determines that the sheet is normal, the sheet determined to be normal is temporarily stored in the stacker 16.

  If the CPU 19 determines that the image formed again by the image inspection unit 13 is normal, the CPU 19 discharges the paper determined to be normal to the normal paper discharge tray T1, and then temporarily stores it in the stacker 16. The discharged sheets are discharged to the normal discharge tray T1 in the order of entering the stacker 16.

Next, the operation of the image forming apparatus 10 will be described.
Each processing is realized by software processing in cooperation with the CPU 19 and a program stored in the ROM 20.

  FIG. 4 is a flowchart showing the transfer process to the output memory executed in the image forming apparatus 10. This process is a process of transferring image data corresponding to each page from the main memory 23 to the output memory 25, and is performed each time an image inspection is performed by the image inspection unit 13 (each sheet).

  First, when it is determined that the image inspection by the image inspection unit 13 is normal (step S1; YES), the CPU 19 stores the image data corresponding to the paper determined to be normal in the output memory 25. The image data is deleted from the storage area where the image data is stored (step S2), and the image data corresponding to the page to be imaged next is transferred from the main memory 23 to the empty storage area of the output memory 25 (step S3). As described above, the CPU 19 writes the image data corresponding to the page to be image-formed next in the page order in the storage area from which the image data corresponding to the paper determined to be normal is deleted.

On the other hand, when it is determined that the image inspection by the image inspection unit 13 is abnormal (step S1; NO), the CPU 19 deletes the image data corresponding to the paper determined to be abnormal from the output memory 25. (Step S4), the image data corresponding to the page to be imaged next is not transferred from the main memory 23 to the output memory 25 (Step S5). That is, in step S4 and step S5, the state of the output memory 25 is maintained as it is.
After step S3 or step S5, the transfer process to the output memory ends.

  FIG. 5 is a flowchart showing output control processing of the output memory executed in the image forming apparatus 10. This process is a process for reading image data stored in the output memory 25 and forming an image on one or a plurality of sheets.

  When image formation by the image forming unit 12 is started (step S11), the CPU 19 determines whether or not the output memory 25 is empty (step S12). Specifically, the CPU 19 determines that the output memory 25 is empty when no data is stored in any of the storage areas A, B, and C of the output memory 25.

  If the output memory 25 is not empty (step S12; NO), the CPU 19 determines whether or not data is stored in the storage area A of the output memory 25 (step S13). If data is stored in the storage area A (step S13; YES), the CPU 19 reads out the image data stored in the storage area A, outputs it to the image forming unit 12, and reads the read image. Based on the data, the image forming unit 12 is caused to form an image (step S14).

  Next, the CPU 19 determines whether data is stored in the storage area B of the output memory 25 (step S15). When data is stored in the storage area B (step S15; YES), the CPU 19 reads out the image data stored in the storage area B and outputs it to the image forming unit 12, and the read image Based on the data, the image forming unit 12 is caused to form an image (step S16).

  Next, the CPU 19 determines whether or not data is stored in the storage area C of the output memory 25 (step S17). When data is stored in the storage area C (step S17; YES), the CPU 19 reads out the image data stored in the storage area C, outputs it to the image forming unit 12, and reads the read image. Based on the data, the image forming unit 12 is caused to form an image (step S18).

  If no data is stored in the storage area A in step S13 (step S13; NO), if no data is stored in the storage area B in step S15 (step S15; NO), in step S17 the storage area When data is not stored in C (step S17; NO), or after step S18, the process returns to step S12 and the process is repeated.

  As described in the transfer process to the output memory (see FIG. 4), when the image inspection unit 13 determines that there is an abnormality, the image data corresponding to the paper determined to be abnormal is output to the output memory. Since the image data is not deleted from the storage area in which the 25 image data is stored, the next time the reading order from the storage area comes around, an image is formed again based on the image data stored in the storage area. Will be.

If the output memory 25 is empty in step S12 (step S12; YES), the image formation is completed (step S19).
This completes the output control process of the output memory.

  FIG. 6 is a flowchart illustrating a transport destination determination process executed in the image forming apparatus 10. This process is a process for determining the sheet transport destination immediately after the image inspection is performed by the image inspection unit 13, and is performed for each sheet.

  First, the CPU 19 causes the image forming unit 12 to start image formation based on image data sequentially output from the output memory 25 (step S21).

  Next, when it is determined that there is an abnormality in the image inspection by the image inspection unit 13 (step S22; NO), the CPU 19 controls the transport unit 22 to discharge the paper after the image inspection for waste paper. It is discharged to the tray T2 (step S23). Specifically, the CPU 19 selects the route R <b> 1 in the route changing unit 14, passes the normal route 15, and then controls the transport unit 22 to select the route R <b> 3 in the route changing unit 17.

  In step S22, when it is determined that the image inspection by the image inspection unit 13 is normal (step S22; YES), the CPU 19 sequentially executes when the paper after the image inspection is discharged to the normal paper discharge tray T1. It is determined whether or not (step S24). For example, when the image inspecting unit 13 determines that an abnormality has occurred, a sheet that was in the middle of image formation or a sheet that has undergone image formation and has not yet been inspected is discharged to the normal discharge tray T1. The paper that is determined to be abnormal is missing, so it does not go in order. In addition, if the paper in the page order after the paper stored in the stacker 16 is discharged to the normal paper discharge tray T1, it does not follow the order.

  If the paper determined to be normal is discharged in the order when it is discharged to the normal paper discharge tray T1 (step S24; YES), the CPU 19 controls the transport unit 22 to load the paper after the image inspection. The paper is discharged to the normal paper discharge tray T1 (step S25). Specifically, the CPU 19 selects the route R <b> 1 in the route changing unit 14, passes the normal route 15, and then controls the transport unit 22 to select the route R <b> 4 in the route changing unit 17.

When the paper determined to be normal in step S24 is not in order when discharged to the normal paper discharge tray T1 (step S24; NO), the CPU 19 controls the transport unit 22 to perform image inspection. The subsequent sheet is stored in the stacker 16 (step S26). Specifically, the CPU 19 selects the route R <b> 2 in the route changing unit 14 and controls the transport unit 22 to transport the paper to the stacker 16.
After step S23, step S25, or step S26, the transport destination determination process ends.

  FIG. 7 is a flowchart showing a discharge process from the stacker executed in the image forming apparatus 10. This process is a process of discharging the paper stored in the stacker 16, and is performed for each paper.

  First, in a state where sheets are stored in the stacker 16 (step S31), the CPU 19 determines whether or not the next sheet to be discharged to the normal discharge tray T1 is in the stacker 16 (step S32). The CPU 19 assumes that the sheets stored in the stacker 16 first in the stacker 16 are discharged to the normal discharge tray T1, and the sheets discharged to the normal discharge tray T1 are sequentially ordered. In this case, it is determined that the next sheet to be discharged to the normal discharge tray T1 is in the stacker 16.

  When the stacker 16 does not have the next sheet to be discharged to the normal discharge tray T1 (step S32; NO), the CPU 19 performs image formation on the basis of image data corresponding to the sheet determined to be abnormal. 12 waits for image formation to be performed again (step S33), and returns to step S32.

In step S32, when the next paper discharged to the normal paper discharge tray T1 is in the stacker 16 (step S32; YES), the CPU 19 controls the transport unit 22 to store the paper stored in the stacker 16. Is discharged to the normal paper discharge tray T1 (step S34). Specifically, the CPU 19 controls the transport unit 22 so that the route changing unit 17 selects the route R5. For example, after the paper that has been determined to be abnormal last time and determined to be normal when the image is formed again is discharged to the normal paper discharge tray T1, the order in which the paper temporarily stored in the stacker 16 enters the stacker 16 As a result, the paper is discharged to the normal paper discharge tray T1.
Thus, the discharge process from the stacker is completed.

Next, a control example of the output memory 25 when an abnormality occurs in the image inspection will be described with reference to FIGS.
FIG. 8A shows the sheet conveyance positions of the first to fifth pages when the image inspection is completed up to the third page in the image forming apparatus 10. The image inspection for the first page and the second page is determined to be normal, and the image inspection for the third page is determined to be abnormal. At this time, the fourth and fifth pages are already in the middle of image formation. The first and second paper sheets determined to be normal are discharged to the normal paper discharge tray T1.

FIG. 8B schematically shows the states of the output memory 25 and the main memory 23 when the image inspection for the third page is completed. Image data corresponding to the third page is stored in the storage area C of the output memory 25, image data corresponding to the fourth page is stored in the storage area A, and image data corresponding to the fifth page is stored in the storage area B. Has been.
The image data corresponding to the fifth page stored in the storage area B of the output memory 25 is output to the image forming unit 12, and the image inspection for the third page is completed before and after the image formation for the fifth page is started. To do.
Here, since it is determined that the third page is abnormal, the image data corresponding to the third page is not deleted from the storage area C of the output memory 25, and the storage area C of the output memory 25 is transferred from the main memory 23. Image data transfer is stopped.

After the data is read from the storage area B of the output memory 25, the data is subsequently read from the storage area C. Therefore, immediately after the formation of the image on the fifth page, as shown in FIGS. As described above, the image data corresponding to the third page stored in the storage area C of the output memory 25 is output to the image forming unit 12, and the image formation of the third page is performed again.
When the image formation for the third page is started, the image inspection for the fourth page is completed. If it is determined to be normal in the image inspection for the fourth page, the image data corresponding to the fourth page is deleted from the storage area A of the output memory 25, and the vacant storage area A is transferred to the sixth page from the main memory 23. Corresponding image data is transferred.
The third page of paper determined to be abnormal (first time) is discharged to the waste paper discharge tray T2, and the fourth page of paper determined to be normal is conveyed to the stacker 16.

When the image formation for the third page stored in the storage area C of the output memory 25 is completed, the six pages stored in the storage area A of the output memory 25 as shown in FIGS. Image data corresponding to the eyes is output to the image forming unit 12 and image formation of the sixth page is performed.
When the image formation for the sixth page is started, the image inspection for the fifth page is completed. If it is determined that the image inspection on the fifth page is normal, the image data corresponding to the fifth page is deleted from the storage area B of the output memory 25, and the vacant storage area B is deleted from the main memory 23 to the seventh page. Corresponding image data is transferred.
The fifth page paper determined to be normal is conveyed to the stacker 16.

When the image formation of the sixth page stored in the storage area A of the output memory 25 is completed, the seventh page stored in the storage area B of the output memory 25 is completed as shown in FIGS. Image data corresponding to the eyes is output to the image forming unit 12, and image formation on the seventh page is performed.
When the image formation for the seventh page is started, the image inspection for the re-formed third page is completed. If it is determined that the image inspection on the third page is normal, the image data corresponding to the third page is deleted from the storage area C of the output memory 25, and the vacant storage area C is deleted from the main memory 23 to the eighth page. Corresponding image data is transferred.
The third page paper (second time) determined to be normal is discharged to the normal paper discharge tray T1 via the normal path 15.

When the image formation for the seventh page stored in the storage area B of the output memory 25 is completed, the eight pages stored in the storage area C of the output memory 25 as shown in FIGS. Image data corresponding to the eyes is output to the image forming unit 12, and image formation on the eighth page is performed.
When the image formation for the eighth page is started, the image inspection for the sixth page is completed. If it is determined that the image inspection on the sixth page is normal, the image data corresponding to the sixth page is deleted from the storage area A of the output memory 25. Here, since there is no image data in the main memory 23 corresponding to the next page to be image formed, the image data is not transferred from the main memory 23 to the output memory 25.
The sixth page of paper determined to be normal is conveyed to the stacker 16.

Subsequently, as shown in FIGS. 13A and 13B, when the image inspection for the seventh page is completed and it is determined that the image inspection for the seventh page is normal, the storage area B of the output memory 25 is stored. The image data corresponding to the seventh page is deleted.
The seventh page paper determined to be normal is conveyed to the stacker 16. The fourth page of paper stored in the stacker 16 is discharged to the normal paper discharge tray T1 after the third page of paper is discharged to the normal paper discharge tray T1.

  Thereafter, similarly, the fifth to seventh pages stored in the stacker 16 are discharged to the normal discharge tray T1. The paper on the eighth page is also discharged to the normal paper discharge tray T1 when it is determined to be normal in the image inspection. At this time, when the image inspection for the eighth page is completed and the sheet for the seventh page is stored in the stacker 16, the sheet for the eighth page is also transferred to the normal discharge tray T1 via the stacker 16. Discharged. On the other hand, when the image inspection for the eighth page is completed and the sheet for the seventh page is not stored in the stacker 16, the sheet for the eighth page passes through the normal path 15 to the normal discharge tray T1. Discharged.

  As described above, according to the image forming apparatus 10 of the present embodiment, the image data corresponding to the paper determined to be abnormal is left in the output memory 25 and circulated from each storage area of the output memory 25. Thus, the image can be easily recreated by a simple control of reading out the image data, and data rewriting in the output memory 25 is not necessary. Therefore, the capacity of the output memory 25 can be suppressed by efficiently and simply controlling the input / output of data to / from the output memory 25 used for image formation.

  Further, the number of storage areas of the output memory 25 is the number of image data corresponding to the sheet existing from the start of image formation to the completion of the image inspection determination along the sheet conveyance path. The number of storage areas in the memory 25 can be minimized, and when it is determined that there is an abnormality, an image can be immediately re-formed. As a result, the number of sheets temporarily stored in the stacker 16, that is, the number of sheets to be ejected after the image that is determined to be abnormal and re-formed, can be suppressed, and the capacity of the stacker 16 can be suppressed.

  Further, according to the determination result by the image inspection unit 13, the paper determined to be normal is discharged to the normal paper discharge tray T1, and the paper determined to be abnormal is discharged to the waste paper discharge tray T2. Therefore, it is possible to prevent the paper determined to be abnormal from being mixed with other paper.

  Further, when the image inspection unit 13 determines that the paper in the middle of the image formation or the paper on which the image has been formed and before the inspection is determined to be normal when it is determined that the image is abnormal, the image is normal. Since the determined paper is temporarily stored in the stacker 16, it is possible to prevent the order of the paper discharged to the normal paper discharge tray T1 from being lost.

  When it is determined that the image formed again is normal, the paper determined to be normal is discharged to the normal paper discharge tray T1, and then the paper temporarily stored in the stacker 16 is stored in the stacker 16. Since the sheets are discharged to the normal paper discharge tray T1 in the order of entering, the sheets can be discharged to the normal paper discharge tray T1 in the order.

  The description in the above embodiment is an example of the image forming apparatus according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of each part constituting the apparatus can be changed as appropriate without departing from the spirit of the present invention.

For example, in the above embodiment, the case where the output memory 25 has the three storage areas A, B, and C has been described. However, the number of storage areas that the output memory 25 has depends on the configuration of the image forming apparatus 10. It can be changed.
Further, in the case of an image forming apparatus that forms an image on both sides of a sheet, as the storage area of the output memory 25, an image corresponding to both sides of the sheet existing from the start of image formation until the determination of image inspection is completed. It is sufficient to prepare as many storage areas as can store data.

  In the above embodiment, the case where the image forming apparatus 10 includes the image forming unit 12 and the image inspection unit 13 has been described. However, the image forming apparatus including the image forming unit, the image inspection apparatus including the image inspection unit, In a separate image forming system, data input / output with respect to the output memory may be controlled similarly.

  In the above description, an example in which a ROM is used as a computer-readable medium storing a program for executing each process is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave may be applied as a medium for providing program data via a communication line.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming part 13 Image inspection part 16 Stacker 18 Paper discharge part 19 CPU
22 Transport unit 23 Main memory 25 Output memory 131 Image reading unit 132 Determination unit T1 Normal paper discharge tray T2 Paper discharge tray for damaged paper

Claims (5)

An image forming unit for forming an image on paper;
An image inspection unit that inspects an image on a sheet formed by the image forming unit and determines whether the image is normal;
A storage unit having a plurality of storage areas and capable of reading data by circulating from the plurality of storage areas;
Image data corresponding to each page is written in page order in each storage area of the storage unit, image data is read out from each storage area of the storage unit, and the image formation is performed based on the read image data. A control unit for forming an image on the unit;
An image forming apparatus comprising:
The controller is
When the image inspection unit determines that the image is normal, the image data corresponding to the paper determined to be normal is deleted from the storage area in which the image data is stored, and the image data is deleted. Write the image data corresponding to the page to be imaged next to the storage area,
When the image inspection unit determines that there is an abnormality, when the reading order from the storage area in which the image data corresponding to the paper determined to be abnormal next time has come, the storage area An image forming apparatus that causes the image forming unit to form an image again based on image data stored in the image forming apparatus.   The number of storage areas that the storage unit has is the number of sheets that exist between the start of image formation by the image forming unit and the completion of determination by the image inspection unit along the sheet transport path of the image forming apparatus. The image forming apparatus according to claim 1, wherein the image forming apparatus matches the number of corresponding image data.   The control unit, when determined to be normal by the image inspection unit, discharges the paper determined to be normal to the first paper discharge tray and determines that the image inspection unit is abnormal. 3. The image forming apparatus according to claim 1, wherein when the error is detected, the sheet determined to be abnormal is discharged to the second discharge tray.   The control unit is a sheet in the middle of image formation by the image forming unit when it is determined to be abnormal by the image inspection unit, or a sheet that has been formed by the image forming unit and is not yet inspected by the image inspection unit. The image forming apparatus according to claim 3, wherein when the image inspection unit determines that the sheet is normal, the sheet determined to be normal is temporarily stored in a stacker.   When the control unit determines that the image formed again by the image inspection unit is normal, the control unit discharges the paper determined to be normal to the first discharge tray, and then The image forming apparatus according to claim 4, wherein the sheets temporarily stored in the stacker are discharged to the first discharge tray in the order of entering the stacker.

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