Image forming apparatus and method for controlling the image forming apparatus

Abstract

To suppress a device from being large-sized and complex although reducing waste sheets.SOLUTION: When an image is formed successively for a plurality of sets, a normal sheet (1-1) is discharged to a stack tray on condition that an image read by a read part is normal, but an abnormal sheet (1-2) is discharged to an escape tray if the image is abnormal. Among a plurality of residual sheets (1-3 to 3-1) where image formation is started after the abnormal sheet at the point of time when the abnormal image is read, sheets (1-3) forming a first set including the abnormal sheet and sheets (2-1) from a starting sheet (2-1) of a second set following the first set to the sheet right before the abnormal sheet of the first set are discharged to the escape tray, and sheets (2-2 to 3-3) in the second set after the abnormal sheet of the first set are subjected to determination processing, so that a discharge destination is selected based upon a result of the determination processing.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a copying machine, a printer, a facsimile machine, or a multifunction machine having a plurality of these functions, for forming an image on a sheet, and a method for controlling the image forming apparatus. [Background technology]

[0002] Conventionally, there is known an electrophotographic image forming apparatus equipped with an inspection device that reads the image of the image-formed sheet and compares it with the original image information to determine whether the image formed on the sheet is good or bad. In such an image forming apparatus, a sheet on which an image is determined to be abnormal is discharged to an escape tray as a defective sheet, and all sheets on which an image has already been formed upstream of the sheet determined to be an abnormal image are discharged as discarded sheets. After that, the sheets after the sheet determined to be an abnormal image are automatically reprinted, making it possible to obtain a high-quality product without the user having to perform special work. However, the sheets on which an image has already been formed upstream of the sheet determined to be abnormal are not necessarily abnormal, and discharging all of them to the escape tray is not preferable because it increases the number of discarded sheets.

[0003] To solve this problem, an image forming apparatus has been developed that is provided with a second conveying path in addition to the first conveying path normally used in the inspection device (see Patent Document 1). In this image forming apparatus, sheets on which images have already been formed upstream of the sheet determined to be an abnormal image are made to wait in the second conveying path. Then, only the sheets determined to be an abnormal image during this time are discharged to an escape tray and reprinted, and normal sheets that have been made to wait thereafter are discharged to a normal tray. With this image forming apparatus, there is no need to discard sheets on which images have already been formed upstream of the sheet determined to be an abnormal image, so the number of discarded sheets can be reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-058564 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the image forming apparatus described in the above-mentioned Patent Document 1, a dedicated second conveying path is provided inside the apparatus body for evacuating sheets on which images have already been formed upstream of the sheet determined to be an abnormal image. Therefore, compared to a case where the second conveying path is not provided, the number of parts increases, and there is a risk that the apparatus will become larger and more complicated.

[0006] The present invention aims to provide an image forming apparatus and a control method for an image forming apparatus that have the function of discharging sheets that have been determined to be abnormal images by an inspection device to an escape tray, thereby reducing the number of discarded sheets while preventing the apparatus from becoming larger and more complicated. [Means for solving the problem]

[0007] The image forming apparatus of the present invention includes an image forming unit which forms an image on a sheet based on image information, a reading unit which reads the image formed on the sheet by the image forming unit, a transport unit which transports the sheet from which the image has been read by the reading unit, a first discharge unit and a second discharge unit to which the sheet transported by the transport unit is selectively discharged, and a control unit which executes a determination process for comparing the image read by the reading unit with image information to determine whether the image is a normal image or an abnormal image, and which selects either the first discharge unit or the second discharge unit as a discharge destination for discharging the sheet based on a result of the determination process, and the control unit is configured to perform image formation on the multiple sheets, one unit being made up of multiple sheets, and to perform image formation on the multiple units in succession. 1.When an image forming job is executed, if the image read by the reading unit is a normal image, the sheet on which the normal image is formed is discharged to the first discharge unit, and if the image read by the reading unit is an abnormal image, the abnormal sheet on which the abnormal image is formed is discharged to the second discharge unit, and among a plurality of remaining sheets on which image formation has started after the abnormal sheet at the time when the abnormal image is read, the sheets constituting a first section including the abnormal sheet and the first sheet in a second section following the first section and the first sheet in a second section following the first section that became the abnormal sheet in the first section are discharged to the second discharge unit. page and the remaining sheets, which are the abnormal sheets in the first section, are discharged to the second discharge section. page For the subsequent sheets, the determination process is executed, and a discharge destination is selected based on the result of the determination process. and when the first part is the last part of the first image forming job and the first part is followed immediately by a sheet on which an image is formed by a second image forming job having an image different from that formed by the first image forming job, all of the remaining sheets are discharged to the second discharge section. It is characterized by:

[0008] A control method for an image forming apparatus of the present invention includes an image forming unit that forms an image on a sheet based on image information, a reading unit that reads the image formed on the sheet by the image forming unit, a transport unit that transports the sheet from which the image has been read by the reading unit, a first discharge unit and a second discharge unit to which the sheet transported by the transport unit is selectively discharged, and a control unit that executes a determination process for comparing the image read by the reading unit with image information to determine whether the image is a normal image or an abnormal image, and selects either the first discharge unit or the second discharge unit as a discharge destination for discharging the sheet based on a result of the determination process, in which one unit is made up of a plurality of sheets, and images are continuously formed on the plurality of units. 1.The image forming apparatus includes a determination step of, when executing an image forming job, comparing an image read by the reading unit with image information to determine whether the image is a normal image or an abnormal image; a first normal discharge step of discharging a sheet on which the normal image is formed to the first discharge unit when the determination step determines that the image read by the reading unit is a normal image; a first abnormal discharge step of discharging an abnormal sheet on which the abnormal image is formed to the second discharge unit when the determination step determines that the image read by the reading unit is an abnormal image; and a first abnormal discharge step of discharging a first part including the abnormal sheet among a plurality of remaining sheets on which image formation has started after the abnormal sheet at the time the abnormal image is read, and a second part including a first part including a first part including a first part including a first part including a first part including a first part including a first part including a first part including a first part including a first part including a first part including a second ... second part including a first part including a second part including a first part including a second part including a second part including a first part page a second abnormality discharge step of discharging the remaining sheets to the second discharge section, and a sheet immediately preceding the remaining sheets, the remaining sheets being discharged from the second discharge section to the second discharge section; page a first selection step of executing the determination process for subsequent sheets and selecting a discharge destination based on the result of the determination process; a third abnormal discharge step of discharging all of the remaining sheets to the second discharge section when the first section is the final section of the first image forming job and the first section is followed immediately by a sheet on which an image is formed by a second image forming job having an image different from that formed by the first image forming job; The present invention is characterized by comprising: Effect of the Invention

[0009] According to the present invention, the inspection device has a function of discharging sheets determined to be defective images to an escape tray, and it is possible to prevent the device from becoming larger and more complicated while reducing the number of discarded sheets. [Brief description of the drawings]

[0010] [Figure 1] 1 is a front view showing a schematic configuration of an image forming system according to an embodiment; [Diagram 2] FIG. 2 is a block diagram showing a control system of the image forming system according to the embodiment. [Diagram 3] 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment. [Figure 4] 5 is a flowchart showing a processing procedure in the printing device according to the embodiment. [Diagram 5]5 is a flowchart showing the first half of a processing procedure in the inspection device according to the embodiment. [Figure 6] 10 is a flowchart showing a second half of the processing procedure in the inspection device according to the embodiment. [Figure 7] 5A to 5C are explanatory diagrams showing changes in the discharge destination in the control method of the image forming apparatus according to the first embodiment. [Figure 8] 13 is an explanatory diagram showing a change in the discharge destination in a control method of an image forming apparatus according to a second embodiment. FIG. [Figure 9] 13A and 13B are explanatory diagrams showing changes in the discharge destination in a control method of an image forming apparatus according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to Figures 1 to 7. In this embodiment, a case in which an image forming apparatus 101 is applied to an image forming system 1 will be described.

[0012] [Outline of image forming system] 1 is an overall diagram of the hardware configuration of an image forming system 1 according to this embodiment. The image forming system 1 includes an image forming apparatus 101 and an external controller 102. The image forming apparatus 101 and the external controller 102 are communicatively connected via an internal LAN 105 and a video cable 106. The external controller 102 is communicatively connected to a client PC 103 via an external LAN 104, and a print instruction is sent from the client PC 103 to the external controller 102.

[0013] A printer driver having a function of converting print data into a print description language that can be processed by the external controller 102 is installed in the client PC 103. A user who performs printing can send a print instruction from various applications via the printer driver. The printer driver installed in the client PC 103 sends print data to the external controller 102 based on a print instruction from the user. When the external controller 102 receives a print instruction from the client PC 103, it performs data analysis and rasterization processing, and sends print data including image information to the image forming apparatus 101 to issue a print instruction.

[0014] The image forming apparatus 101 is connected to a plurality of devices having different functions, and is configured to be capable of performing complex printing processes such as bookbinding. In this embodiment, the image forming apparatus 101 has a printing device 107, an inspection device 108, and a first stacker 111 and a second stacker 112 that are large-capacity stackers. The image forming apparatus 101 may also be called a multifunction machine, a multifunction peripheral, or an MFP. In this embodiment, the sheets that are recording materials are those on which a toner image is formed, and specific examples include plain paper, synthetic resin sheets that are substitutes for plain paper, cardboard, and sheets for overhead projectors.

[0015] The printing device 107 forms an image on a sheet conveyed from the feeding cassettes 301 and 302 at the bottom of the printing device 107 using toner. That is, the printing device 107 is an example of an image forming unit that forms an image on a sheet based on image information. The inspection device 108 is a device that reads an image of a sheet conveyed from the printing device 107 and compares it with a correct image registered in advance to determine whether the printed image is normal. That is, the inspection device 108 is an example of a reading unit that reads an image formed on a sheet by the printing device 107. The first stacker 111 and the second stacker 112 are large-capacity stackers that can stack a large amount of sheets. Note that the image forming system 1 described in FIG. 1 is configured such that the external controller 102 is connected to the image forming device 101, but the present invention is not limited to the configuration in which the external controller 102 is connected. That is, the image forming device 101 may be connected to an external LAN 104, and print data that can be processed by the image forming device 101 may be transmitted from the client PC 103. In this case, data analysis and rasterization processing are performed in the image forming apparatus 101, and printing processing is executed.

[0016] [Image formation system control system] FIG. 2 is a block diagram showing a system configuration of the image forming apparatus 101, the external controller 102, and the client PC 103. As shown in FIG.

[0017] First, the configuration of the printing device 107 will be described. The printing device 107 has a communication I / F 217, a LAN I / F 218, a video I / F 220, a HDD 221, a CPU 222, a memory 223, an operation unit 224, a display 225, a laser exposure unit 227, an image creating unit 228, a fixing unit 229, and a feeding unit 230. Each of the components is connected via a system bus 231. In this embodiment, a tandem type full-color printer is described as an example of the printing device 107. However, the present invention is not limited to the tandem type printing device 107, and may be an image forming device of another type, and is not limited to being full-color, but may be monochrome or monocolor.

[0018] The communication I / F (interface) 217 ​​is connected to the inspection device 108, the first stacker 111, and the second stacker 112 via a communication cable 249, and performs communication for controlling each device. The LAN I / F 218 is connected to the external controller 102 via the internal LAN 105, and performs communication of print data and the like. The video I / F 220 is connected to the external controller 102 via a video cable 106, and performs communication of image data and the like. The HDD 221 is a storage device in which programs and data are stored. The CPU 222 comprehensively controls image processing and printing based on the programs and the like stored in the HDD 221. The memory 223 stores programs and image data required when the CPU 222 performs various processes, and operates as a work area. The operation unit 224 accepts various setting inputs and operation instructions from the user. The display 225 displays setting information of the image forming device 101, the processing status of a print job, and the like.

[0019] The laser exposure unit 227 is a device that performs primary charging and laser exposure to irradiate the photosensitive drum with laser light in order to transfer a toner image. In the laser exposure unit 227, first, primary charging is performed to charge the surface of the photosensitive drum to a uniform negative potential. Next, the laser driver irradiates the photosensitive drum with laser light while adjusting the reflection angle with a polygon mirror. This neutralizes the negative charge of the irradiated area, and an electrostatic latent image is formed. The image creation unit 228 is a device for transferring toner to a sheet, and is composed of a development unit, a transfer unit, a toner supply unit, etc., and transfers the toner on the photosensitive drum to a sheet. In the development unit, negatively charged toner from a development cylinder is attached to the electrostatic latent image on the photosensitive drum surface to make it visible. In the transfer unit, primary transfer is performed by applying a positive potential to the primary transfer roller to transfer the toner on the photosensitive drum surface to the transfer belt, and secondary transfer is performed by applying a positive potential to the secondary transfer outer roller to transfer the toner on the transfer belt to the sheet. The fixing unit 229 is a device for melting and fixing the toner on the sheet to the sheet by heat and pressure, and is composed of a heater, a fixing belt, a pressure belt, etc. The feeding unit 230 is a device for feeding the sheet, and the sheet feeding operation and conveying operation are controlled by rollers and various sensors.

[0020] Next, the configuration of the inspection device 108 will be described. The inspection device 108 has a communication I / F 232, a CPU 233 which is an example of a control unit, a memory 234, an image reading unit 235, a display unit 236, an operation unit 237, and an image processing unit 238, and each of the components is connected via a system bus 250. The communication I / F 232 is connected to the printing device 107 via a communication cable 249, and communication required for control is performed. The memory 234 is a storage device in which a control program is stored. The image reading unit 235 reads an image on the conveyed sheet based on an instruction from the CPU 233. The CPU 233 performs various controls required for inspection according to the control program stored in the memory 234. The CPU 233 compares the image read by the image reading unit 235 with the correct image stored in the memory 234, and judges whether the printed image is normal. The display unit 236 displays the inspection result, a setting screen, and the like. The operation unit 237 is operated by a user to receive instructions such as changing the settings of the inspection device 108 and registering a correct image. The image processing unit 238 sets a gain adjustment value for image reading by the image reading unit 235 and reflects the setting in the image reading result.

[0021] Next, the configuration of the first stacker 111 will be described. The first stacker 111 has a communication I / F 239, a CPU 240, a memory 241, and a discharge control unit 242, and each of the components is connected via a system bus 243. The communication I / F 239 is connected to the printing device 107 via a communication cable 249, and communication required for control is performed. The CPU 240 performs various controls required for discharge according to a control program stored in the memory 241. The memory 241 is a storage device in which the control program is saved. The discharge control unit 242 performs control to convey the conveyed sheet to a stack tray 331 (see FIG. 3), which is a first stack tray, or an escape tray 334 (see FIG. 3), based on an instruction from the CPU 240. Next, the configuration of the second stacker 112 will be described. The second stacker 112 has a communication I / F 244, a CPU 245, a memory 246, and a discharge control unit 247, and each of the components is connected via a system bus 248. The configuration of each part is the same as that of the first stacker 111, so a detailed description will be omitted.

[0022] Next, the configuration of the external controller 102 will be described. The external controller 102 may also be called an image processing controller, a digital front end, a print server, a DFE, or the like. The external controller 102 has a CPU 208, a memory 209, a HDD 210, a keyboard 211, a display 212, a LAN I / F 213, a LAN I / F 214, and a video I / F 215, which are connected via a system bus 216. The CPU 208 comprehensively executes processes such as receiving print data from the client PC 103, RIP processing, and sending print data to the image forming apparatus 101 based on the programs and data stored in the HDD 210. The memory 209 stores programs and data required for the CPU 208 to perform various processes, and operates as a work area. The HDD 210 stores programs and data required for operations such as print processing. The keyboard 211 is a device for inputting operation instructions for the external controller 102. The display 212 can display information such as an application executed by the external controller 102 using video signals of still images and moving images. The LAN I / F 213 is connected to the client PC 103 via the external LAN 104, and performs communication such as print instructions. The LAN I / F 214 is connected to the image forming apparatus 101 via the internal LAN 105, and performs communication such as print instructions. The video I / F 215 is connected to the image forming apparatus 101 via the video cable 106, and performs communication such as print data.

[0023] Next, the configuration of the client PC 103 will be described. The client PC 103 has a CPU 201, a memory 202, a HDD 203, a keyboard 204, a display 205, and a LAN I / F 206, which are connected via a system bus 207. The CPU 201 creates print data and issues print instructions based on a document processing program or the like stored in the HDD 203, and comprehensively controls each device connected to the system bus. The memory 202 stores programs and data required for the CPU 201 to perform various processes, and operates as a work area. The HDD 203 stores programs and data required for operations such as print processing. The keyboard 204 is a device for inputting operation instructions for the client PC 103. The display 205 displays information such as an application executed by the client PC 103 by video signals of still images and moving images. The LAN I / F 206 is connected to the external LAN 104, and communication such as print instructions is performed.

[0024] In the above description, the external controller 102 and the image forming apparatus 101 are connected by the internal LAN 105 and the video cable 106, but any other configuration is acceptable as long as data necessary for printing can be transmitted and received, and for example, a connection configuration using only a video cable is also acceptable. Also, each of the memories 202, 209, 223, 234, 241, and 246 may be a storage device for holding data and programs. For example, they may be replaced by volatile RAM, non-volatile ROM, built-in HDD, external HDD, USB memory, or the like.

[0025] [Image forming device] FIG. 3 is a cross-sectional view of the image forming apparatus 101. The configuration and operation principle of the printing apparatus 107 are as follows. In the printing apparatus 107, various sheets can be stored in the feeding cassettes 301 and 302. In each feeding cassette 301 and 302, only the topmost sheet of the stored sheets can be separated and conveyed to a sheet conveying path 303. In the developing stations 304 to 307, toner images are formed using color toners of Y, M, C, and K, respectively, to form color images. In each of the developing stations 304 to 307, a light beam such as a laser beam modulated according to image data is reflected by a rotating polygon mirror such as a polygon mirror and irradiated onto a photosensitive drum as a scanning light. An electrostatic latent image formed on the photosensitive drum by this laser beam is developed with toner, and the toner image is primarily transferred to an intermediate transfer belt 308. This series of image forming processes is performed sequentially for yellow (Y), magenta (M), cyan (C), and black (K) toners, forming a full-color image on intermediate transfer belt 308. Intermediate transfer belt 308 rotates clockwise in FIG. 3, and the toner image is secondarily transferred to a sheet conveyed from sheet conveying path 303 at secondary transfer position 309, and the sheet is conveyed to first fixing unit 311. First fixing unit 311 includes a pressure roller and a heating roller, and fixes the toner image to the sheet by melting and pressing the toner as the sheet passes between the rollers. The sheet that has passed through first fixing unit 311 is conveyed to sheet conveying path 315 through sheet conveying path 312.

[0026] If further melting and pressing are required for fixing depending on the type of sheet, the sheet passes through the first fixing unit 311 and is then conveyed to the second fixing unit 313 by the upper sheet conveying path. After additional melting and pressing are performed on the sheet in the second fixing unit 313, the sheet is conveyed to the sheet conveying path 315 through the sheet conveying path 314. If the image forming mode is the double-sided mode, the sheet is conveyed to the sheet inverting path 316, inverted by the sheet inverting path 316, and conveyed to the double-sided conveying path 317, where the image is transferred to the back side at the secondary transfer position 309. The display 225 displays the printing status of the image forming apparatus 101 and information for settings.

[0027] The sheet that has passed through the printing device 107 is conveyed to the inspection device 108. In the inspection device 108, a first CIS unit 321 and a second CIS unit 322 are disposed facing each other. The first CIS unit 321 is a CIS unit for reading the upper surface of the sheet, and the second CIS unit 322 is a CIS unit for reading the lower surface of the sheet. When the sheet conveyed to the sheet conveying path 323 reaches a predetermined position, the inspection device 108 reads the image of the sheet using the first CIS unit 321 and the second CIS unit 322, and judges whether the image is normal or not based on the reading result. The display unit 236 displays the inspection result performed by the inspection device 108. The first CIS unit 321 and the second CIS unit 322 are not limited to being constituted by a CIS unit as a sensor, and may be constituted by other optical sensors such as a CCD or a CMOS. The sheet transport path 323 is an example of a transport section that transports the sheet whose image has been read by the inspection device 108.

[0028] [1st stacker] The first stacker 111 has a stack tray 331, which is an example of a first discharge section serving as a tray for stacking sheets, and an escape tray 334, which is an example of a second discharge section serving as a discharge tray. A sheet that has passed through the inspection device 108 is transported to the first stacker 111. The sheet is stacked on the stack tray 331 via a sheet transport path 332 and a sheet transport path 333. The escape tray 334 is a discharge tray used to discharge a sheet whose image has been determined to be abnormal by the inspection device 108. When outputting to the escape tray 334, the sheet is transported from the sheet transport path 332 to the escape tray 334 via a sheet transport path 335. When transporting the sheet to a post-processing device subsequent to the first stacker 111, the sheet is transported via a sheet transport path 336.

[0029] The reversing unit 337 is provided for reversing sheets, and is used when the sheets are stacked on the stack tray 331. That is, when the sheets are to be stacked on the stack tray 331 so that the orientation of the input sheet is the same as the orientation of the sheet at the time of output, the sheets are reversed by the reversing unit 337. When the sheets are to be conveyed to the escape tray 334 or a subsequent post-processing device, the sheets are discharged as is, and therefore the reversing operation by the reversing unit 337 is not performed.

[0030] [Second stacker] The second stacker 112 has a second stack tray 341 as a tray for stacking sheets, and a tray 344. The sheet that has passed through the first stacker 111 is transported to the second stacker 112. The sheet is stacked on the second stack tray 341 via a sheet transport path 342 and a sheet transport path 343. When outputting to the tray 344, the sheet is transported from the sheet transport path 342 to the tray 344 via a sheet transport path 345. The reversing unit 347 is provided to reverse the sheet, and is used when stacking the sheet on the second stack tray 341. That is, when stacking the sheet on the second stack tray 341 so that the orientation of the input sheet and the orientation of the sheet at the time of output are the same, the sheet is reversed by the reversing unit 347. When transporting to the tray 344, the sheet is discharged as is, so that the reversing operation is not performed by the reversing unit 347.

[0031] In this embodiment, a sheet conveyed by a sheet conveying path 332 of the inspection device 108 is selectively discharged from the stack tray 331 or the escape tray 334. A CPU 233 of the inspection device 108 executes a determination process for comparing an image read by the inspection device 108 with image information to determine whether the image is normal or abnormal. Furthermore, the CPU 233 selects either the stack tray 331 or the escape tray 334 as a discharge destination for discharging the sheet based on the result of the determination process.

[0032] [Inspection system] A sheet whose image is determined to be abnormal by the inspection device 108 is discharged to the escape tray 334 and needs to undergo recovery printing. At the time when an image is determined to be abnormal, image formation has already started on several sheets (called residual sheets) upstream of the inspection device 108 in the printing device 107. In other words, the residual sheets refer to a plurality of sheets on which image formation has started after the abnormal sheet at the time when the abnormal image is read. However, if all the residual sheets are discharged to the escape tray 334 in order to guarantee the stacking order of the sheets and then recovery printing is performed starting with the sheet determined to be abnormal, productivity will decrease and all the remaining sheets will be discarded.

[0033] Therefore, in this embodiment, in an image forming job in which multiple copies are formed, among sheets on which images have already been formed, the next copy and the sheet immediately preceding the page of the sheet determined to be abnormal are discharged to the escape tray 334. Then, the next copy and the sheets subsequent to the page of the sheet determined to be abnormal are discharged to the stack tray 331. This makes it possible to reduce the number of discarded sheets without reducing productivity.

[0034] Hereinafter, the processing procedure regarding the inspection process in each part of the image forming system 1 will be described in detail with reference to the flowcharts of FIGS.

[0035] [Printing device processing] Fig. 4 is a flowchart showing the flow of the process performed by the printing device 107 before performing the inspection process. The process in Fig. 4 is executed by the CPU 222 of the printing device 107. First, the CPU 222 determines whether or not a print instruction (image formation job) has been received from the external controller 102 (step S1). If the CPU 222 determines that a print instruction has not been received from the external controller 102 (NO in step S1), it again determines whether or not a print instruction has been received from the external controller 102 (step S1).

[0036] When the CPU 222 determines that a print instruction has been received from the external controller 102 (YES in step S1), the printing device 107 starts printing according to the received image formation job (step S2). Here, it is assumed that the number of copies to be printed is set to X copies and the number of pages of each copy is set to Y pages in the image formation job to be executed. These X and Y may be singular or plural. Note that the image formation job is the image formation instruction content received from the user, and refers to the following series of operations performed based on a print command signal (image formation command signal). That is, it refers to the period from pre-rotation (preparatory operation before image formation) after receiving the print command signal (input of image formation job) to post-rotation (operation after image formation), and includes the image formation period and paper interval (non-image formation time).

[0037] The CPU 222 assigns an initial value of 1 to each of the copy counter I and the page counter J (step S3), prints the Jth page of the Ith copy, and conveys the page to the inspection device 108 (step S4). The CPU 222 determines whether the page counter J is Y or not (step S5) to confirm that printing of all pages of the Ith copy has been completed. If the CPU 222 determines that the page counter J is not Y (NO in step S5), printing of all pages of the Ith copy has not been completed, so the page counter J is incremented by one (step S6) and the next page is printed (step S4).

[0038] If the CPU 222 determines that the page counter J is Y (YES in step S5), printing of all pages of the Ith copy has been completed, and then determines whether the copy counter I is X to confirm that printing of all copies has been completed (step S7). If the CPU 222 determines that the copy counter I is not X (NO in step S7), printing of all copies has not been completed, so the CPU 222 increments the copy counter I by one and assigns 1 to the page counter J (step S8), and prints the next page (step S4).

[0039] When the CPU 222 determines that the copy counter I is X (YES in step S7), it determines whether or not there was a sheet discharged to the escape tray 334 in the image forming job being executed (step S9). The CPU 222 makes this determination based on, for example, whether or not the CPU 233 of the inspection device 108 has set the sheet discharge destination to the escape tray 334. When the CPU 222 determines that there was a sheet discharged to the escape tray 334 in the image forming job being executed (YES in step S9), there is one copy less than the number of copies X set in the image forming job, as described later. Therefore, the CPU 222 additionally prints one copy and conveys it to the inspection device 108 (step S30). After that, since all copies have been printed, the processing of the printing device 107 is terminated. When the CPU 222 determines that there was no sheet discharged to the escape tray 334 in the image forming job being executed (NO in step S9), since all copies have been printed, the processing of the printing device 107 is terminated.

[0040] [Processing of inspection equipment] 5 and 6 are flowcharts showing the flow of the process performed by the inspection device 108 when performing the inspection process. The process in FIG. 5 and FIG. 6 is executed by the CPU 233 of the inspection device 108. The CPU 233 judges whether or not an inspection end instruction has been received from the printing device 107 (step S10). If the CPU 233 judges that an inspection end instruction has been received from the printing device 107 (YES in step S10), the process of the inspection device 108 ends. If the CPU 233 judges that an inspection end instruction has not been received from the printing device 107 (NO in step S10), the CPU 233 judges whether or not a sheet has been conveyed to the inspection device 108 (step S11). If the CPU 233 judges that a sheet has not been conveyed to the inspection device 108 (NO in step S11), the CPU 233 judges again whether or not an inspection end instruction has been received (step S10).

[0041] When the CPU 233 determines that the sheet has been conveyed to the inspection device 108 (YES in step S11), it determines whether or not the inspection unnecessary flag stored in the memory 234 is off (step S12). When the CPU 233 determines that the inspection unnecessary flag stored in the memory 234 is off (YES in step S12), it performs an inspection process (determination process) (step S13). The CPU 233 compares the image read from the conveyed sheet with the correct image, and determines whether the read image is a normal image or an abnormal image, that is, whether the inspection is OK (step S14).

[0042] When it is determined that the inspection is OK (YES in step S14), the CPU 233 sets the discharge destination of the sheet on which the normal image is formed to the stack tray 331 (step S15), and again determines whether or not an inspection end instruction has been received (step S10). The discharge destination set here is notified to the first stacker 111 via the printing device 107, and the sheet is discharged to the stack tray 331.

[0043] When the CPU 233 determines that the sheet is not inspection OK (NO in step S14), it sets the discharge destination of the sheet on which the abnormal image is formed to the escape tray 334 (step S16). The discharge destination set here is notified to the first stacker 111 via the printing device 107, and the sheet is discharged to the escape tray 334. The CPU 233 determines whether the copy counter I is X or not (step S17) to confirm that the copy including the sheet is the last copy of the image forming job. When the CPU 233 determines that the copy counter I is not X (NO in step S17), it proceeds to step S18 as the copy including the sheet is not the last copy of the image forming job.

[0044] The CPU 233 compares the copy counter I and page counter J of the next sheet with the copy counter I and page counter J of the current sheet to determine whether the next sheet is the same page image as the sheet that has failed inspection. Specifically, the CPU 233 determines whether the copy counter I of the next sheet is not the copy counter I of the current sheet and the page counter J of the next sheet is equal to the page counter J of the current sheet (step S18). If the copy counter I of the next sheet is not the copy counter I of the current sheet and the page counter J of the next sheet is equal to the page counter J of the current sheet, the image of the next sheet is the same as the normal image of the sheet that has failed inspection, that is, one copy is only one sheet. Therefore, if the CPU 233 determines that the copy counter I of the next sheet is not the copy counter I of the current sheet and the page counter J of the next sheet is equal to the page counter J of the current sheet (YES in step S18), it again determines whether to issue an inspection end instruction (step S10).

[0045] On the other hand, in step S18, if the copy counter I of the next sheet is equal to the copy counter I of the sheet, or the page counter J of the next sheet is not equal to the page counter J of the sheet, the image of the next sheet is different from the normal image of the sheet that has failed inspection. Therefore, when the CPU 233 determines that the counter I of the next sheet is not equal to the counter I of the sheet, and the counter J of the next sheet is not equal to the counter J of the sheet (NO in step S18), it turns on the inspection unnecessary flag stored in the memory 234 (step S19). As a result, the result in step S12 becomes NO, and the judgment process in step S13 is not performed. The CPU 233 stores the copy counter I and page counter J of the sheet in the memory 234 (step S20), and again judges whether or not an inspection end instruction has been received (step S10).

[0046] Furthermore, when the CPU 233 determines in step S17 that the copy counter I is X (YES in step S17), the copy including the sheet on which the abnormal image is formed is the last copy of the image forming job. Therefore, the CPU 233 ejects all remaining sheets to the escape tray 334 (step S21), and starts reprinting from the sheet on which the abnormal image is formed and which has failed inspection (step S22). After that, the CPU 233 again determines whether or not an inspection end instruction has been received (step S10).

[0047] Furthermore, when the CPU 233 determines in step S12 that the inspection unnecessary flag stored in the memory 234 is not OFF (NO in step S12), it sets the discharge destination of the sheet to the escape tray 334 (step S23). The discharge destination set here is notified to the first stacker 111 via the printing device 107, and the sheet is discharged to the escape tray 334.

[0048] The CPU 233 compares the copy counter I and page counter J of the next sheet with the copy counter I and page counter J of the sheet in order to determine whether the next sheet is the same page image as the sheet that has failed inspection. Specifically, the CPU 233 determines whether the copy counter I of the next sheet is not the copy counter I of the sheet in question and the page counter J of the next sheet is equal to the page counter J of the sheet in question (step S24). The determination in step S24 is the same as that in step S18. Here, if the copy counter I of the next sheet is not the copy counter I of the sheet in question and the page counter J of the next sheet is equal to the page counter J of the sheet in question, the image of the next sheet is the same as the normal image of the sheet that has failed inspection. Therefore, if the CPU 233 determines that the counter I of the next sheet is not the counter I of the sheet in question and the counter J of the next sheet is equal to the counter J of the sheet in question (YES in step S24), it turns off the inspection unnecessary flag (step S25). As a result, for the remaining sheets that have been discharged to the escape tray 334 in response to the occurrence of an abnormal sheet, the determination process is resumed, and the discharge destination can be selected based on the result of the determination process. After that, the CPU 233 again determines whether or not an inspection end instruction has been received (step S10).

[0049] In step S24, if the copy counter I of the next sheet is equal to the copy counter I of the sheet in question, or the page counter J of the next sheet is not equal to the page counter J of the sheet in question, the image of the next sheet is different from the normal image of the sheet that has failed inspection. Therefore, when the CPU 233 determines that the counter I of the next sheet is not equal to the counter I of the sheet in question, and the counter J of the next sheet is not equal to the counter J of the sheet in question (NO in step S24), it again determines whether or not an inspection end instruction has been received (step S10).

[0050] (First Example) A specific first embodiment using the image forming apparatus 101 described above will be described with reference to FIG. 7. Here, it is assumed that one copy is composed of a plurality of sheets (e.g., three sheets), and an image forming job is executed to continuously form a plurality of set copies (e.g., three copies). First, the CPU 233 compares the image read by the inspection device 108 with image information to determine whether the image is normal or abnormal (determination step). If the image read by the inspection device 108 is a normal image, the sheet (1-1) on which the normal image is formed is discharged to the stack tray 331 (first normal discharge step). If the image read by the inspection device 108 is an abnormal image, the abnormal sheet (1-2) on which the abnormal image is formed is discharged to the escape tray 334 (first abnormal discharge step).

[0051] The remaining sheets (1-3 to 3-1) are the sheets on which image formation has started after the abnormal sheet (1-2) at the time the abnormal image is read. Among the remaining sheets (1-3 to 3-1), the sheet (1-3) constituting the first section (1-1 to 1-3) including the abnormal sheet (1-2) is first discharged to the escape tray 334. Then, among the remaining sheets, the first sheet (2-1) in the second section (2-1 to 2-3) following the first section to the sheet (2-1) one sheet before the number of sheets that became the abnormal sheet (1-2) in the first section are discharged to the escape tray 334 (second abnormality discharge process). For the sheets (2-2 to 3-3) in the second section (2-1 to 2-3) after the number of sheets (2-2) that became the abnormal sheet (1-2) in the first section, the images read by the inspection device 108 are compared with the image information to determine whether they are normal images or abnormal images. Then, based on the result of this determination process, a discharge destination is selected (first selection step).

[0052] Then, image formation is performed by the printing device 107 until the number of copies discharged onto the stack tray 331 reaches the set number of copies to be printed in the image formation job (recovery printing, R-1 to R-3), and the copies are discharged onto the stack tray 331 (second normal discharge step). In this way, the control method for the image forming device 101 according to the first embodiment includes a determination step, a first normal discharge step, a first abnormal discharge step, a second abnormal discharge step, a first selection step, and a second normal discharge step. Note that the second normal discharge step does not have to be executed automatically, and may be executed at the user's instruction after a warning is issued to the user that an abnormal image has occurred.

[0053] (Second Example) Next, a specific second embodiment using the image forming apparatus 101 described above will be described with reference to FIG. 8. Here, it is assumed that a first image forming job is executed in which one copy is composed of a plurality of sheets (e.g., three sheets) and a plurality of set copies (e.g., two copies) are image-formed continuously. Then, it is assumed that a second image forming job is executed in which one copy is composed of, for example, three sheets and two copies are image-formed continuously after the first image forming job is completed. The second image forming job forms a different image from the first image forming job. Here, it is assumed that a second image forming job is executed in succession after the first image forming job is completed, and the remaining sheets include sheets on which images are formed by the second image forming job. It is also assumed that the abnormal sheet is not the last copy of the first image forming job. In this case, the CPU 233 executes the determination process, the first normal discharge process, the first abnormal discharge process, the second abnormal discharge process, and the first selection process, as in the first embodiment.

[0054] Then, the CPU 233 discharges the sheets (2-2 to 2-3) in the second section, from the abnormal sheet number (2-2) in the first section to the last sheet (2-3) of the last section of the first image forming job, onto the stack tray 331. The CPU 233 discharges the sheet (A-1) on which an image is formed by the second image forming job, out of the remaining sheets, onto the escape tray 334 (third abnormality discharge process).

[0055] Then, image formation is performed by the printing device 107 until the number of copies discharged onto the stack tray 331 reaches the set number of copies (recovery printing, R-1 to R-3), and the copies are discharged onto the stack tray 331 (second normal discharge step). In this manner, the control method for the image forming apparatus 101 according to the second embodiment includes a determination step, a first normal discharge step, a first abnormal discharge step, a second abnormal discharge step, a first selection step, a third abnormal discharge step, and a second normal discharge step. The second image formation job is executed after the image formation in the second normal discharge step is completed.

[0056] (Third Example) Next, a specific third embodiment using the image forming apparatus 101 described above will be described with reference to FIG. 9. Here, it is assumed that a first image forming job is executed in which one copy is composed of a plurality of sheets (e.g., three sheets) and a plurality of set copies (e.g., two copies) are image-formed continuously. Then, it is assumed that a second image forming job is executed in which one copy is composed of, for example, three sheets and two copies are image-formed continuously after the first image forming job is completed. The second image forming job forms a different image from the first image forming job. Here, it is assumed that a second image forming job is executed in succession after the first image forming job is completed, and the remaining sheets include sheets on which images are formed by the second image forming job. Also, it is assumed that the abnormal sheet (2-2) is included in the last copy of the first image forming job. That is, the last copy (2-1 to 2-3) of the first image forming job is immediately followed by a sheet (A-1) on which images are formed by the second image forming job. In this case, the CPU 233 executes the determination step, the first normal discharge step, and the first abnormal discharge step, similarly to the first embodiment.

[0057] The CPU 233 discharges all the remaining sheets (2-3 to B-1) to the escape tray 334 (fourth abnormal discharge step). Then, for the sheets (2-2 to 2-3) after the abnormal sheet number, image formation is performed by the printing device 107 (recovery printing, R-2 to R-3). At this time, for the sheets (2-2 to 2-3) after the abnormal sheet number, the image read by the inspection device 108 is compared with the image information to determine whether the image is normal or abnormal, and a discharge destination is selected based on the result of the determination process (second selection step). In this way, the control method of the image forming device 101 according to the third embodiment includes a determination step, a first normal discharge step, a first abnormal discharge step, a fourth abnormal discharge step, and a second selection step. The second image formation job is executed after the image formation in the second selection step is completed.

[0058] As described above, according to the image forming apparatus 101 of the present embodiment, when an abnormal sheet is detected by the inspection device 108, the remaining sheets from the abnormal sheet to the sheet just before the same number in the next set are discharged to the escape tray 334. This makes it possible to reduce the number of discarded sheets compared to when all the remaining sheets are discharged to the escape tray 334. Moreover, since a dedicated conveying path for temporarily evacuating some of the remaining sheets is not required, an increase in the number of parts can be avoided. This makes it possible to reduce the number of discarded sheets while suppressing the increase in size and complexity of the image forming apparatus 101 having a function for discharging a sheet determined to be an abnormal image by the inspection device 108 to the escape tray 334.

[0059] According to the image forming apparatus 101 of this embodiment, the CPU 233 executes image formation until the number of copies discharged to the stack tray 331 reaches the number of copies set for the image formation job, and discharges the copies to the stack tray 331. Therefore, even if the sheets from the sheet on which the abnormal image is formed to the sheet just before the same number of the next copy are discharged to the escape tray 334, the sheets can be compensated for, and the operability for the user can be improved.

[0060] Furthermore, according to the image forming apparatus 101 of this embodiment, a second image forming job may be executed continuously after the first image forming job is completed, and the remaining sheets may include sheets on which an image is formed by the second image forming job. That is, if the sheet on which the abnormal image is formed is not the last copy of the first image forming job, the sheets from the sheet on which the abnormal image is formed to the sheet just before the same number of sheets in the next copy can be discharged to the escape tray 334, and the number of discarded sheets can be reduced. Also, if the sheet on which the abnormal image is formed is the last copy of the first image forming job, it is possible to deal with this by discharging all the remaining sheets to the escape tray 334.

[0061] In the image forming apparatus 101 of the present embodiment described above, during processing by the printing device 107, it is determined whether or not an additional copy needs to be printed by detecting whether or not discharge to the escape tray 334 has occurred after printing of all copies of the image formation job has been completed. However, this is not limited to this, and for example, processing may be performed to increment the number of copies to be printed X by 1 when discharge to the escape tray 334 has occurred during processing by the inspection device 108.

[0062] In addition, in the image forming apparatus 101 of the present embodiment described above, the stack tray 331 and the escape tray 334 are used as the discharge destinations for the sheets, but the present invention is not limited to this. For example, the image forming apparatus 101 may have three or more discharge destinations including the second stack tray 341. [Explanation of symbols]

[0063] 101...image forming apparatus, 107...printing apparatus (image forming section), 108...inspection device (reading section), 233...CPU (control section), 323...sheet transport path (transport section), 331...stack tray (first discharge section), 334...escape tray (second discharge section)

Claims

1. an image forming unit that forms an image on a sheet based on image information; a reading unit that reads an image formed on a sheet by the image forming unit; a conveying unit that conveys the sheet on which the image has been read by the reading unit; a first discharge section and a second discharge section to which the sheet conveyed by the conveying section is selectively discharged; a control unit that executes a determination process for comparing an image read by the reading unit with image information to determine whether the image is a normal image or an abnormal image, and selects either the first discharge unit or the second discharge unit as a discharge destination for discharging a sheet based on a result of the determination process; The control unit is When a first image forming job is executed in which one copy is composed of a plurality of sheets and the plurality of copies are continuously image-formed, When the image read by the reading section is a normal image, the sheet on which the normal image is formed is discharged to the first discharge section; If the image read by the reading section is an abnormal image, the abnormal sheet on which the abnormal image is formed is discharged to the second discharge section; Among the remaining sheets on which image formation has started after the abnormal sheet at the time when the abnormal image is read, the sheets constituting a first section including the abnormal sheet and the sheets from the first sheet in a second section following the first section to the sheet just before the page of the abnormal sheet in the first section are discharged to the second discharge section; For the remaining sheets in the second section, sheets following the page that became the abnormal sheet in the first section can be subjected to the determination process, and a discharge destination can be selected based on the result of the determination process. When the first part is the last part of the first image forming job and the first part is followed immediately by a sheet on which an image is formed by a second image forming job having an image different from that formed by the first image forming job, all of the remaining sheets are discharged to the second discharge section.

1. An image forming apparatus comprising:

2. the control unit continues image formation by the image forming unit until the number of copies discharged to the first discharge unit reaches the number of copies to be printed in the first image forming job, and discharges the copies to the first discharge unit.

2. The image forming apparatus according to claim 1,

3. An image forming unit that forms an image on a sheet based on image information; a reading unit that reads an image formed on a sheet by the image forming unit; a conveying unit that conveys the sheet on which the image has been read by the reading unit; a first discharge section and a second discharge section to which the sheet conveyed by the conveying section is selectively discharged; a control unit that executes a determination process for determining whether an image read by the reading unit is a normal image or an abnormal image by comparing the image with image information, and selects either the first discharge unit or the second discharge unit as a discharge destination for discharging a sheet based on a result of the determination process, When a first image forming job is executed in which one copy is composed of a plurality of sheets and the plurality of copies are continuously image-formed, a determination step of comparing the image read by the reading unit with image information to determine whether the image is normal or abnormal; a first normal discharge step of discharging the sheet on which the normal image is formed to the first discharge section when the image read by the reading section is determined to be a normal image in the determination step; a first abnormality discharge step of discharging the abnormal sheet on which the abnormal image is formed to the second discharge step when the image read by the reading unit is determined to be an abnormal image in the determination step; a second abnormality discharge step of discharging to the second discharge section sheets constituting a first section including the abnormal sheet among a plurality of remaining sheets on which image formation has started after the abnormal sheet at the time when the abnormal image is read, and sheets from the first sheet in a second section following the first section to the sheet just before the page of the abnormal sheet in the first section; a first selection step of executing the determination process for the remaining sheets in the second section that are subsequent to the page that is the abnormal sheet in the first section, and selecting a discharge destination based on the result of the determination process; a third abnormal discharge step of discharging all of the remaining sheets to the second discharge section when the first section is the final section of the first image forming job and the first section is followed immediately by a sheet on which an image is formed by a second image forming job having an image different from that formed by the first image forming job. 2 is a control method for an image forming apparatus according to claim 1 .

4. A second normal discharge step is provided in which image formation is performed by the image forming unit until the number of copies discharged to the first discharge unit reaches the number of copies to be printed in the first image formation job, and the copies are discharged to the first discharge unit.

4. The method for controlling an image forming apparatus according to claim 3.

Images