Image forming apparatus and method for controlling the image forming apparatus

Abstract

To suppress the increase in the size and complication of an apparatus while reducing waste sheets.SOLUTION: In a case of executing an image formation job in which one copy is constituted by plural sheets and which continuously performs image formation of plural copies, when an image read by a reading unit is a normal image, an image formation apparatus discharges a sheet (1-1) formed with the normal image to a first stack tray. When the image read by the reading unit is an abnormal image, the image formation apparatus discharges an abnormal sheet (1-2) formed with the abnormal image to an escape tray. The image formation apparatus discharges to the escape tray a sheet (1-3) constituting a first copy including the abnormal sheet (1-2) among a plurality of residual sheets (1-3 to 3-1) for which the image formation is started subsequently to the abnormal sheet (1-2) at a time point where the abnormal image is read. The image formation apparatus discharges to a second stack tray the sheets (2-1 to 3-1) not constituting the first copy among the residual sheets.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a copier, printer, facsimile, or 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, a second discharge unit, and a third discharge unit to which the sheets transported by the transport unit are selectively discharged, and a control unit which compares the image read by the reading unit with image information to determine whether it is a normal image or an abnormal image, and which selects a discharge destination for discharging the sheet from among the first discharge unit, the second discharge unit, and the third discharge unit, wherein the control unit is configured as one unit for a plurality of sheets, and When executing an image formation job for continuously forming images of multiple copies, 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 the multiple remaining sheets on which image formation began after the abnormal sheet at the time the abnormal image was read, the sheets constituting the first copy which included the abnormal sheet are discharged to the second discharge unit, and among the remaining sheets, sheets which do not constitute the first copy are discharged to the third discharge unit.

[0008] Also, an 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, a second discharge unit, and a third discharge unit to which the sheet transported by the transport unit is selectively discharged, and a control unit which compares the image read by the reading unit with image information to determine whether it is a normal image or an abnormal image, and selects a discharge destination for discharging the sheet from among the first discharge unit, the second discharge unit, and the third discharge unit, and the control unit selectively selects the first discharge unit and the third discharge unit as a discharge unit for discharging the sheet on which the normal image has been formed when the image read by the reading unit is a normal image. The image forming apparatus selectively executes a first mode in which the image read by the reading unit is used, and a second mode in which the first discharge unit is used without using the third discharge unit, and in the first mode, 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 began after the abnormal sheet at the time the abnormal image was read, sheets constituting a first section which included the abnormal sheet are discharged to the second discharge unit, and sheets of the remaining sheets which do not constitute the first section are discharged to the third discharge unit, and in the second mode, if the image read by the reading unit is an abnormal image, the abnormal sheet on which the abnormal image is formed and the remaining sheets are discharged to the second discharge unit.

[0009] 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, a second discharge unit, and a third discharge unit to which the sheet transported by the transport unit is selectively discharged, and a control unit that compares the image read by the reading unit with image information to determine whether the image is normal or abnormal and selects a discharge destination for discharging the sheet from among the first discharge unit, the second discharge unit, and the third discharge unit. In the control method for an image forming apparatus, the image forming unit is configured with a plurality of sheets, and when an image forming job is executed in which a plurality of copies are continuously formed, the image read by the reading unit is compared with image information to determine whether the image is normal or abnormal. The image forming apparatus is characterized in that it comprises a determination step for determining whether the image is a normal image or an abnormal image, a first normal discharge step for discharging the sheet on which the normal image is formed to the first discharge step if it is determined in the determination step that the image read by the reading unit is a normal image, a first abnormal discharge step for discharging the abnormal sheet on which the abnormal image is formed to the second discharge step if it is determined in the determination step that the image read by the reading unit is an abnormal image, a second abnormal discharge step for discharging to the second discharge step sheets constituting a first section which included the abnormal sheet among a plurality of remaining sheets on which image formation began after the abnormal sheet at the time the abnormal image was read, and a second normal discharge step for discharging to the third discharge section sheets of the remaining sheets which do not constitute the first section.

[0010] A control method for an image forming apparatus according to 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, and a first discharge unit, a second discharge unit, and a third discharge unit to which the sheet transported by the transport unit is selectively discharged, and a control method for determining whether the image read by the reading unit is a normal image or an abnormal image by comparing the image read by the reading unit with image information and determining whether the image is a normal image or an abnormal image and determining a discharge destination for the sheet to be discharged to one of the first discharge unit, the second discharge unit, and the third discharge unit. and a control unit for selecting from among a first mode, a second mode, a third mode, and a fourth mode, the first mode, the second mode, and the third mode, the third mode, and the first mode, the second mode, and the third mode, the third mode, and the first mode, and the third ... the image reading unit is compared with the 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 if it is determined in the determination step that the image read by the reading unit is a normal image; a first abnormal discharge step of discharging the abnormal sheet on which the abnormal image is formed to the second discharge section if it is determined in the determination step that the image read by the reading unit is an abnormal image; a second abnormal discharge step of discharging to the second discharge section sheets constituting a first section which included the abnormal sheet among a plurality of remaining sheets on which image formation began after the abnormal sheet at the time the abnormal image was read; and a second normal discharge step of discharging to the third discharge section sheets of the remaining sheets which do not constitute the first section, and in the second mode, the image reading unit is characterized in that the image reading unit is compared with the image information to determine whether the image is normal or abnormal; Effect of the Invention

[0011] 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]

[0012] [Figure 1] 1 is a front view showing a schematic configuration of an image forming system according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a control system of the image forming system according to the first embodiment. [Diagram 3] 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment. [Figure 4] FIG. 2 is an explanatory diagram showing a state when a discharge destination is set on the display of the external controller according to the first embodiment. [Diagram 5] 5 is a flowchart showing a processing procedure in an external controller according to the first embodiment. [Figure 6] 5 is a flowchart showing the first half of a processing procedure in the printing device according to the first embodiment. [Figure 7] 6 is a flowchart showing the second half of the processing procedure in the printing device according to the first embodiment. [Figure 8] 5 is a flowchart showing the first half of a processing procedure in the inspection device according to the first embodiment. [Figure 9] 6 is a flowchart showing a second half of the processing procedure in the inspection device according to the first embodiment. [Figure 10] 5 is a flowchart showing a processing procedure in the stacker according to the first embodiment. [Figure 11] FIG. 2 is an explanatory diagram showing a change in a discharge destination in the image forming apparatus according to the first embodiment. [Figure 12] FIG. 11 is an explanatory diagram showing a state when a discharge destination is changed on the display of an external controller according to the second embodiment. [Figure 13]10 is a flowchart showing a processing procedure in an external controller according to the second embodiment. [Figure 14] 10 is a flowchart showing the first half of a processing procedure in a printing device according to a second embodiment. [Figure 15] 10 is a flowchart showing the second half of the processing procedure in the printing device according to the second embodiment. [Figure 16] FIG. 13 is an explanatory diagram showing a state when a discharge destination is set on the display of an external controller according to the third embodiment. [Figure 17] 13 is a flowchart showing a processing procedure in an external controller according to the third embodiment. [Figure 18] 13 is a flowchart showing the first half of a processing procedure in a printing device according to a third embodiment. [Figure 19] 13 is a flowchart showing the second half of the processing procedure in the printing device according to the third embodiment. [Figure 20] 13 is a flowchart showing the first half of a processing procedure in an inspection device according to a third embodiment. [Figure 21] 13 is a flowchart showing a second half of the processing procedure in the inspection device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <First embodiment> A first embodiment of the present invention will be described in detail below with reference to Figures 1 to 11. In this embodiment, a case in which an image forming apparatus 101 is applied to an image forming system 1 will be described.

[0014] [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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] [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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 the first stack tray 331 (see FIG. 3) or the 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] [Image forming equipment] 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.

[0028] 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.

[0029] 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.

[0030] [1st stacker] The first stacker 111 has a first 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 first 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 downstream of the first stacker 111, the sheet is transported via a sheet transport path 336.

[0031] The reversing unit 337 is provided for reversing sheets, and is used when the sheets are stacked on the first stack tray 331. That is, when the sheets are to be stacked on the first 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.

[0032] [Second stacker] The second stacker 112 has a second stack tray 341, which is an example of a third discharge unit serving 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.

[0033] In this embodiment, a sheet transported by a sheet transport path 332 of the inspection device 108 is selectively discharged from a first stack tray 331, a second stack tray 341, or an escape tray 334. A CPU 233 of the inspection device 108 compares an image read by the inspection device 108 with image information to determine whether the image is normal or abnormal, and selects a discharge destination for the sheet from among the trays 331, 341, and 334.

[0034] [Discharge destination settings] FIG. 4 is an example of a screen displayed on the display 212 of the external controller 102. The button 401 for setting the discharge destination allows the selection of "Automatic", "First stack tray", or "Second stack tray". When "Automatic" is selected, the external controller 102 sets the discharge destination designation as automatic. When "First stack tray" is selected, the external controller 102 sets the first stack tray 331 as the discharge destination. When "Second stack tray" is selected, the external controller 102 sets the second stack tray 341 as the discharge destination. The button 402 for setting the priority discharge destination allows the selection of "First stack tray" or "Second stack tray". When "First stack tray" is selected, the external controller 102 sets the first stack tray 331 as the discharge destination when the discharge destination designation is automatic. When "Second stack tray" is selected, the external controller 102 sets the second stack tray 341 as the discharge destination when the discharge destination designation is automatic.

[0035] [Inspection system] A sheet whose image is determined to be abnormal by the inspection device 108 is discharged to the escape tray 334 and recovery printing is required. At the time when an image is determined to be abnormal, image formation has already started on several sheets (referred to as "residual sheets") upstream of the inspection device 108 in the printing device 107. That is, 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. Here, when the first stack tray 331 is designated by the button 401 in FIG. 4, only the first stack tray 331 is used as the discharge destination of normal sheets. For this reason, in order to guarantee the stacking order of the sheets, all the residual sheets are discharged to the escape tray 334, and then recovery printing is performed on the sheet determined to be abnormal. This reduces productivity, and all the residual sheets are discarded.

[0036] In contrast, in this embodiment, in order to reduce discarded sheets without reducing productivity, when the user sets the discharge destination to automatic, if the discharge destination of the first sheet of a set is on standby for recovery, the discharge destination is switched to another discharge destination that is not on standby for recovery. By switching the discharge destination for the first sheet of a set, a discharge destination different from the discharge destination on standby for recovery is specified for the subsequent copies of the sheet determined to be abnormal. Therefore, the subsequent copies of the sheet determined to be abnormal can be discharged as deliverables without being discarded.

[0037] Hereinafter, the processing procedure regarding the inspection processing in each part of the image forming system 1 will be described in detail with reference to the flowcharts of FIGS.

[0038] [Processing in external controller] Fig. 5 is a flowchart showing the flow of processing when various settings are made to the external controller 102. Each process shown in Fig. 5 is executed by the CPU 208 of the external controller 102. When the external controller 102 is started, the CPU 208 judges whether or not a stop instruction has been received from the user (step S1). If the CPU 208 judges that a stop instruction has been received from the user (YES in step S1), it ends the processing of the external controller 102.

[0039] When CPU 208 determines that it has not received a stop instruction from the user (NO in step S1), it receives a print instruction from the user (step S2). When CPU 208 receives a print instruction from the user, it acquires the settings of the number of copies of the job, the discharge destination designation, and the priority discharge destination designation. Here, a case will be described in which the number of copies of the job is set to X, the discharge destination designation to Y, and the priority discharge destination designation to Z. The discharge destination designation Y and the priority discharge destination designation Z are settings designated on the screen of display 212 shown in FIG.

[0040] The CPU 208 assigns an initial value of 0 to I (step S3). The CPU 208 assigns I+1 to I and counts up (step S4). The CPU 208 determines whether the discharge destination designation Y is automatic or not (step S5). If the CPU 208 determines that the discharge destination designation Y is automatic (YES in step S5), it assigns the priority discharge destination designation Z to the external controller designated discharge destination J (step S6). If the CPU 208 determines that the discharge destination designation Y is not automatic (NO in step S5), it assigns the discharge destination designation Y to the external controller designated discharge destination J (step S7).

[0041] CPU 208 instructs printer 107 to print copy I (step S8). At this time, CPU 208 sets the designated discharge destination to Y and the designated discharge destination of the external controller to J. CPU 208 determines whether I is equal to X (step S9). If CPU 208 determines that I is not equal to X (NO in step S9), printing of all copies is not complete, so CPU 208 again assigns I+1 to I and counts up (step S4). If CPU 208 determines that I is equal to X (YES in step S9), printing of all copies is complete, so CPU 208 again determines whether a stop instruction has been received from the user (step S1).

[0042] [Printing process] 6 and 7 are flowcharts showing the flow of the process performed by the printing device 107 before the inspection process is performed. The process in FIG. 6 and FIG. 7 is executed by the CPU 222 of the printing device 107. When the printing device 107 is started, the CPU 222 assigns an initial value of 0 to the discharge destination buffer A (step S11). The CPU 222 judges whether the printing device 107 has received a stop instruction (step S12). If the CPU 222 judges that the printing device 107 has received a stop instruction (YES in step S12), the processing of the printing device 107 is terminated. If the CPU 222 judges that the printing device 107 has not received a stop instruction (NO in step S12), the CPU 222 receives a print instruction from the external controller 102 (step S13). This corresponds to the case where the external controller 102 issues a print instruction to the printing device 107 in step S8 shown in FIG. 5.

[0043] The CPU 222 judges whether the destination Y is automatic (step S14). If the CPU 222 judges that the destination Y is automatic (YES in step S14), it judges whether the destination buffer A is the initial value 0 (step S15). If the CPU 222 judges that the destination buffer A is the initial value 0 (YES in step S15), it assigns the external controller designated destination J to the destination buffer A (step S16) and assigns the destination buffer A to the destination K (step S17). If the CPU 222 judges that the destination buffer A is not the initial value 0 (NO in step S15), it assigns the destination buffer A to the destination K (step S17). If the CPU 222 judges that the destination Y is not automatic (NO in step S14), it assigns the destination Y to the destination K (step S18).

[0044] The CPU 222 prints the image formation job received from the external controller 102, designates K as the discharge destination, and conveys the image formation job to the inspection device 108 (step S19). The CPU 222 controls the inspection device 108, the first stacker 111, and the second stacker 112 via the communication cable 249 according to the contents of the image formation job received from the external controller 102. The CPU 222 receives a discharge completion notification from the first stacker 111 or the second stacker 112 (step S20). Note that the image formation job is the image formation instruction contents received from the user, and is a series of operations as follows that are performed based on a print command signal (image formation instruction signal). That is, it refers to the period from pre-rotation (preparatory operation before image formation) after receiving a print command signal (input of an image formation job) to post-rotation (operation after image formation), and includes the image formation period and the paper interval (non-image formation period). However, in this embodiment, the image formation job may mean, in addition to the above definition, that the printing device 107 forms an image on one sheet.

[0045] The CPU 222 judges whether the sheet was discharged normally (step S21). If the CPU 222 judges that the sheet was discharged normally (YES in step S21), it judges whether the discharge destination Y is automatic (step S22). If the CPU 222 judges that the discharge destination Y is automatic (YES in step S22), it designates the discharge destination of the discharge completion notification received in step S20 as the discharge destination buffer A (step S23), and judges whether a stop instruction has been received again (step S12). If the CPU 222 judges that the discharge destination Y is not automatic (NO in step S22), it does not change the discharge destination buffer A, and judges again whether a stop instruction has been received (step S12). If the CPU 222 judges that the sheet was not discharged normally (NO in step S21), it performs recovery of the sheet that was not discharged normally by reprinting the print data (step S24), and judges again whether a stop instruction has been received (step S12).

[0046] [Processing of inspection equipment] 8 and 9 are flowcharts showing the flow of the process performed by the inspection device 108 when performing the inspection process. The process in FIG. 8 and FIG. 9 is executed by the CPU 233 of the inspection device 108. The CPU 233 judges whether or not a sheet has been conveyed to the inspection device 108 (step S31). When the CPU 233 judges that a sheet has not been conveyed to the inspection device 108 (NO in step S31), the process of the inspection device 108 ends. When the CPU 233 judges that a sheet has been conveyed to the inspection device 108 (YES in step S31), the CPU 233 reads an image of the sheet using the first CIS unit 321 and the second CIS unit 322, and stores the image in the memory 234 of the inspection device 108 (step S32). The CPU 233 compares the read image with the correct image (step S33).

[0047] The CPU 233 judges whether the read image is a normal image or not based on a comparison between the read image and the correct image (step S34, judgment step). That is, the CPU 233 judges whether the image read by the inspection device 108 is a normal image or an abnormal image by comparing it with the image information. When the CPU 233 judges that the read image is not a normal image (NO in step S34), it changes the original discharge destination L to the discharge destination K (step S38). Since the sheet with the abnormal image needs to be discharged to the discharge destination K by recovery printing, the CPU 233 sets the discharge destination K to a recovery standby state (step S39). The CPU 233 notifies the first stacker 111 of inspection NG discharge (step S40, first abnormal discharge step) and ends the processing of the inspection device 108. That is, when it is judged that the image read by the inspection device 108 is an abnormal image in the judgment step, it discharges the abnormal sheet on which the abnormal image is formed to the escape tray 334.

[0048] If the CPU 233 determines that the read image is a normal image (YES in step S34), it determines whether the print sheet is recovery printed or not (step S35). If the CPU 233 determines that the print sheet is not recovery printed (NO in step S35), it determines whether the print sheet is the first sheet of a set and whether the discharge destination Y is automatic (step S36). In this embodiment, the timing for setting recovery printing is after printing of the set that includes the last sheet of remaining sheets is completed, and at that point a stop instruction is issued to start recovery printing.

[0049] If the CPU 233 determines that the printed sheet is the first sheet of a set and that the designated discharge destination Y is automatic (YES in step S36), it determines whether the designated discharge destination K is on standby for recovery (step S44). If the CPU 233 determines that the designated discharge destination K is not on standby for recovery (NO in step S44), it notifies the discharge destination K determined in the previous processing of the inspection device of inspection OK discharge (step S48, first normal discharge step), and ends the processing of the inspection device 108. That is, if the CPU 233 determines that the image read by the inspection device 108 in the judgment step is a normal image, it discharges the sheet on which the normal image is formed to the first stack tray 331.

[0050] In this manner, in this embodiment, the image formation job is considered to have already started image formation output of the next copy of sheets when the sheet reaches the inspection device 108. In such an image formation job, when the CPU 233 determines the discharge destination of the first sheet of a copy, if the intended discharge destination is not available, the CPU 233 determines the available discharge destination of the first stack tray 331 or the second stack tray 341 as the discharge destination of the copy.

[0051] When the CPU 233 determines that the designated discharge destination K is waiting for recovery (YES in step S44), it determines whether the designated discharge destination K is the first stacker 111 (step S45). When the CPU 233 determines that the designated discharge destination K is the first stacker 111 (YES in step S45), it changes the discharge destination K to the second stacker 112 (step S46). The CPU 233 notifies the confirmed discharge destination K of inspection OK discharge (step S48, second normal discharge step), and ends the processing of the inspection device 108. That is, among the remaining sheets, sheets that do not constitute the first set including the abnormal sheet are discharged to the second stack tray 341.

[0052] If the CPU 233 determines that the specified discharge destination K is not the first stacker 111 (NO in step S45), the specified discharge destination K is the second stacker 112, and therefore changes the discharge destination K to the first stacker 111 (step S47). The CPU 233 notifies the confirmed discharge destination K of inspection OK discharge (step S48), and ends the processing of the inspection device 108.

[0053] When the CPU 233 determines that the printed sheet is the first sheet of a set and the discharge destination Y is not automatic (NO in step S36), it determines whether the specified discharge destination K is on standby for recovery (step S37). Here, when it is determined that the printed sheet is the first sheet of a set and the discharge destination Y is not automatic, it means at least one of the following: the printed sheet is not the first sheet of a set, or the discharge destination Y is not automatic. When the CPU 233 determines that the specified discharge destination K is not on standby for recovery (NO in step S37), it notifies the confirmed discharge destination K of inspection OK discharge (step S48, supplementary step), and ends the processing of the inspection device 108. That is, in the second set including the last sheet of the remaining sheets, for the sheets on which image formation by the printer 107 has not been performed at the time when the abnormal image was read, image formation by the printer 107 is performed. Then, after the execution, the sheet on which the image has been formed is discharged to the second stack tray 341. When the CPU 233 determines that the specified discharge destination K is waiting for recovery (YES in step S37), it notifies the first stacker 111 of inspection NG discharge (step S40, second abnormal discharge step), and ends the processing of the inspection device 108. That is, among the multiple remaining sheets, the sheets constituting the first set, which includes the abnormal sheet, are discharged to the escape tray 334.

[0054] When the CPU 233 determines that the printed sheet is a recovery print (YES in step S35), it determines whether the original discharge destination L is on standby for recovery (step S41). When the CPU 233 determines that the original discharge destination L is on standby for recovery (YES in step S41), it cancels the standby for recovery of the original discharge destination L (step S42) and changes the discharge destination K to the original discharge destination L (step S43). This allows the sheet printed by the recovery printing to be discharged to the original discharge destination. The CPU 233 notifies the confirmed discharge destination K of inspection OK discharge (step S48) and ends the process of the inspection device 108. That is, for the sheets on which images have been formed by the printer 107 from the abnormal sheet constituting the first copy to the final sheet of the first copy, the printer 107 performs image formation again, and then discharges the image-formed sheets to the first stack tray 331.

[0055] If the CPU 233 determines that the original discharge destination L is not waiting for recovery (NO in step S41), since this is the second or subsequent sheet of recovery printing, it leaves the discharge destination as it is and notifies the confirmed discharge destination K of inspection OK discharge (step S48). Thereafter, the processing of the inspection device 108 ends. In this embodiment, the CPU 233 determines whether or not the printer is waiting for recovery in steps S44 and S37, but this is not limited thereto, and the external controller 102 or the printer 107 may make this determination.

[0056] [Stacker processing] 10 is a flowchart showing the flow of processing performed by the first stacker 111 and the second stacker 112. The processing in FIG. 10 is executed by the CPU 240 of the first stacker 111 or the CPU 245 of the second stacker 112. The CPUs 240, 245 receive a discharge notification from the inspection device 108 (step S51). This corresponds to the case where the inspection device 108 issues a discharge notification to the first stacker 111 or the second stacker 112 in step S40 or step S48 shown in FIG. 7.

[0057] The CPU 240, 245 judges whether the notification is an inspection OK ejection notification (step S52). If the CPU 240, 245 judges that the notification is an inspection OK ejection notification (YES in step S52), the first stacker 111 ejects the document to the first stack tray 331, and the second stacker 112 ejects the document to the second stack tray 341 (step S53). This step S53 corresponds to a part of the first normal ejection process, the second normal ejection process, the supplementary process, and the first recovery process. If the CPU 240, 245 judges that the notification is not an inspection OK ejection notification (NO in step S52), the first stacker 111 ejects the document to the escape tray 334, and the second stacker 112 ejects the document to the tray 344 (step S54, first abnormal ejection process, second abnormal ejection process).

[0058] After step S53 or step S54 is completed, the CPU 240, 245 notifies the printing device 107 of the completion of ejection (step S55), and ends the processing of the first stacker 111 and the second stacker 112. The ejection completion notification corresponds to the case where the printing device 107 receives the ejection completion notification in step S20 of FIG.

[0059] (Example) A specific embodiment using the image forming apparatus 101 described above will be described with reference to FIG. 11. 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 images of a plurality of copies (e.g., four 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 first 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).

[0060] At the time when the abnormal image (1-2) is read, the multiple sheets on which image formation has started after the abnormal sheet (1-2) are referred to as remaining sheets (1-3 to 3-1). Among these remaining sheets (1-3 to 3-1), the sheet (1-3) constituting the first set (1-1 to 1-3) including the abnormal sheet (1-2) is discharged to the escape tray 334 (second abnormal discharge process). Among the remaining sheets (1-3 to 3-1), the sheets (2-1 to 3-1) not constituting the first set (1-1 to 1-3) are discharged to the second stack tray 341 (second normal discharge process).

[0061] There is an image formation job for forming an image on the second set (3-1 to 3-3) including the final sheet (3-1) of the remaining sheets (1-3 to 3-1). Among the image formation jobs, the unexecuted image formation jobs subsequent to the image formation job that formed an image on the final sheet (3-1) are handled as follows. That is, after the unexecuted image formation job is executed (complementary printing), the sheets (3-2 to 3-3) on which the images are formed are discharged to the second stack tray 341 (complementary process). At this point, the printing state is switched from normal printing to recovery printing.

[0062] Then, there is an image formation job in which images are formed on the abnormal sheet (1-2) constituting the first copy (1-1 to 1-3) through the final sheet (1-3) of the first copy. For this image formation job, the image formation job is executed again (recovery printing), and then the sheets (1-2 to 1-3) on which the images are formed are discharged to the first stack tray 331 (first recovery step). After the recovery printing is completed, the printing state is switched to normal printing, and an image formation job is executed for the last fourth copy, and then the sheets (4-1 to 4-3) on which the images are formed are discharged to the first stack tray 331.

[0063] Thus, the control method of the image forming apparatus 101 in this embodiment includes a judgment process, a first normal ejection process, a first abnormal ejection process, a second abnormal ejection process, a second normal ejection process, a complementation process, and a first recovery process.

[0064] In this embodiment, the image forming job for the sheets (3-2 to 3-3) is executed before the image forming job for the sheets (1-2 to 1-3). That is, the first recovery step is executed after the completion step is executed. However, this order is not limited, and the image forming job for the sheets (3-2 to 3-3) may be executed after the image forming job for the sheets (1-2 to 1-3). That is, the completion step may be executed after the first recovery step is executed. In this case, when the sheets (2-1 to 3-1) that do not constitute the first set (1-1 to 1-3) among the remaining sheets (1-3 to 3-1) are discharged to the second stack tray 341, the printing state is switched from normal printing to recovery printing. Alternatively, after the completion step, the last fourth set may be printed, and then the first recovery step may be executed. In this case, when the printing of the last fourth set is completed, the printing state is switched from normal printing to recovery printing.

[0065] If an inspection NG occurs again by the inspection device 108 before the first stack tray 331 is released from recovery standby by recovery printing, the first stack tray 331 and the second stack tray 341 will be in recovery standby. Therefore, all remaining sheets at that time are discharged to the escape tray 344, and recovery printing is executed for the first stack tray 331 and the second stack tray 341.

[0066] As described above, according to the image forming apparatus 101 of the present embodiment, the sheets constituting the first set including the abnormal sheet among the remaining sheets are discharged to the escape tray 334, and the sheets not constituting the first set are discharged to the second stack tray 341. That is, when the inspection device 108 judges an abnormality in the print image, all the sheets judged as abnormal upstream of the sheet judged as abnormal are discharged to the escape tray 334. Then, the next set after the set judged as abnormal are discharged to a possible discharge destination when the leading sheet of the set reaches the inspection device 108. Therefore, it is possible to reduce the number of discarded sheets compared to the case where 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, it is possible to avoid an increase in the number of parts. As a result, in the image forming apparatus 101 having the function of discharging the sheet judged as an abnormal image by the inspection device 108 to the escape tray 334, it is possible to suppress the size and complexity of the apparatus while reducing the number of discarded sheets.

[0067] Furthermore, according to image forming apparatus 101 of this embodiment, if the image is normal (inspection OK), the discharge destination specified in step S13 is not changed, and the image is discharged to the same discharge destination J until an inspection NG occurs. After the copy after the inspection NG occurs, the copy is discharged to a different discharge destination than the copy after the inspection NG. Therefore, sheets of the same copy as the one with inspection NG are discharged to escape tray 334 and become discarded sheets, but after the copy with inspection NG, sheets can be discharged without being discarded. Also, since printing is not stopped, productivity does not decrease.

[0068] Furthermore, according to the image forming apparatus 101 of this embodiment, as shown in the example, the image forming job for sheets (3-2 to 3-3) is executed before the image forming job for sheets (1-2 to 1-3). That is, the first recovery process is executed after the complement process is executed. Therefore, the number of times the discharge destination is switched after all the remaining sheets are discharged can be set to at least once, which allows for simpler control.

[0069] In the above-described embodiment of the image forming apparatus 101, the image forming job for the sheets (3-2 to 3-3) is executed before the image forming job for the sheets (1-2 to 1-3), but the present invention is not limited to this. For example, the image forming job for the sheets (3-2 to 3-3) may be executed after the image forming job for the sheets (1-2 to 1-3). In this case, the sheets are quickly discharged to the first stack tray 331 where they should be discharged, improving the user experience.

[0070] In addition, in the control method of the image forming apparatus 101 of the present embodiment described above, a case has been described in which the determination step, the first normal discharge step, the first abnormal discharge step, the second abnormal discharge step, the second normal discharge step, the supplement step, and the first recovery step are provided. However, this is not limited to this, and as long as the control method includes at least the determination step, the first normal discharge step, the first abnormal discharge step, the second abnormal discharge step, and the second normal discharge step, the number of discarded sheets can be reduced compared to the case in which all remaining sheets are discharged to the escape tray 334.

[0071] <Second embodiment> Next, a second embodiment of the present invention will be described in detail with reference to Fig. 12 to Fig. 15. This embodiment is different from the first embodiment in that a notification is given when the discharge destination is changed. However, other configurations are the same as those of the first embodiment, so the same reference numerals are used and detailed description is omitted.

[0072] 12, in the present embodiment, when an inspection NG occurs, a message is displayed on the display 212, which is an example of a display unit of the external controller 102 (see FIG. 2), informing the user that the discharge destination is to be changed to the second stack tray 341 due to the inspection NG. That is, when the discharge destination for discharging the sheet is changed from among the first stack tray 331, the second stack tray 341, and the escape tray 334, the display 212 displays a message indicating that the discharge destination has been changed.

[0073] FIG. 13 is a flowchart showing the flow of the process performed by the external controller 102 when displaying a message. Each process shown in FIG. 13 is executed by the CPU 208 of the external controller 102. Note that the flowchart shown in FIG. 13 is partially common to the flowchart shown in FIG. 5, so the common parts are indicated by the same step numbers and detailed explanations are omitted. As shown in FIG. 13, the CPU 208 instructs the printing device 107 to print the Ith copy (step S8) and judges whether or not a discharge destination change notice has been received from the printing device 107 (step S61). When the CPU 208 judges that a discharge destination change notice has been received from the printing device 107 (YES in step S61), it displays the discharge destination change on the display 212 of the external controller 102 (step S62, change display step). The screen displayed at this time is the display 212 shown in FIG. 12. After displaying, the CPU 208 judges whether or not I is equal to X (step S9). Moreover, if the CPU 208 determines that it has not received a discharge destination change notification from the printing device 107 (NO in step S61), it determines whether I is equal to X without making any display (step S9).

[0074] Figures 14 and 15 are flowcharts showing the flow of processing performed by the printing device 107 when displaying a message. The processing in Figures 14 and 15 is executed by the CPU 222 of the printing device 107. Note that the flowcharts shown in Figures 14 and 15 share some parts in common with the flowcharts shown in Figures 6 and 7, so the common parts are indicated by the same step numbers and detailed descriptions are omitted.

[0075] 15, when the CPU 222 determines that the discharge destination designation Y is automatic (YES in step S22), it determines whether or not the discharge destination buffer A is the same as the notification source discharge destination of the discharge completion notification received in step S20 (step S63). When the CPU 222 determines that the discharge destination buffer A is the same as the notification source discharge destination of the discharge completion notification received in step S20 (YES in step S63), it does not change the discharge destination buffer A and determines again whether or not a stop instruction has been received (step S12).

[0076] When the CPU 222 determines that the discharge destination buffer A is not equal to the notification source discharge destination of the discharge completion notification received in step S20 (NO in step S63), the CPU 222 designates the notification source discharge destination of the discharge completion notification received in step S20 as the discharge destination buffer A (step S23). The CPU 222 notifies the external controller 102 of the change of the discharge destination. This corresponds to step S61 in FIG. 13.

[0077] As described above, according to the image forming apparatus 101 of this embodiment, when the discharge destination to which the sheets are discharged is changed among the first stack tray 331, the second stack tray 341, and the escape tray 334, the display 212 displays a message to that effect. This allows the user to know in real time that the discharge destination to which the sheets are discharged has been changed, thereby improving operability.

[0078] <Third embodiment> Next, a third embodiment of the present invention will be described in detail with reference to Fig. 16 to Fig. 21. This embodiment is different from the first embodiment in that the user can set the discharge destination to be switched when an abnormal image is detected. However, other configurations are the same as those of the first embodiment, so the same reference numerals are used and detailed description is omitted.

[0079] FIG. 16 shows an example of a display screen when setting the discharge destination to be changed. The screen shown in FIG. 16 is displayed on the display 212 of the external controller 102 (see FIG. 2). The button 403 is for setting the discharge tray to be changed to, and "Do not change" or "Second stack tray" can be selected. When "Do not change" is selected, the discharge destination is not changed even if an inspection NG occurs and the discharge destination is waiting for recovery. When "Second stack tray" is selected, the discharge destination is switched to the second stack tray 341 when the discharge destination is waiting for recovery. That is, in this embodiment, the display 212 has the button 403 for setting the discharge destination to be changed, and when the discharge destination of the first sheet of a set is to be determined, if the scheduled discharge destination is not available, the discharge destination set by the button 403 is determined as the discharge destination.

[0080] In the image forming apparatus 101 of this embodiment, the CPU 208 can selectively execute a first mode or a second mode for a discharge section that discharges a sheet on which a normal image is formed when an image read by the inspection device 108 is a normal image. The first mode here is a mode in which the first stack tray 331 and the second stack tray 341 are selectively used, and is the case when "second stack tray" is selected with the button 403. The second mode is a mode in which the first stack tray 331 is used without using the second stack tray 341, and is the case when "do not change" is selected with the button 403.

[0081] Fig. 17 is a flowchart showing the flow of processing performed by the external controller 102 when setting a new discharge destination. The processing shown in Fig. 17 is executed by the CPU 208 of the external controller 102. Note that the flowchart shown in Fig. 17 shares some parts with the flowchart shown in Fig. 5, so the common parts are indicated by the same step numbers and detailed explanations are omitted.

[0082] When the CPU 208 determines that it has not received a stop instruction from the user (NO in step S1), it receives a print instruction from the user (step S71). When the CPU 208 receives a print instruction from the user, it acquires the settings of the number of copies of the job, the discharge destination designation, the priority discharge destination designation, and the change destination designation. Here, a case will be described in which the number of copies of the job is set as X, the discharge destination designation as Y, the priority discharge destination designation as Z, and the change destination designation as P. The CPU 208 also assigns the priority discharge destination designation Z to the external controller designated discharge destination J (step S6) or assigns the discharge destination designation Y to the external controller designated discharge destination J (step S7), and instructs the printer 107 to print the Ith copy (step S72). At this time, the CPU 208 sets the discharge destination designation to Y, the external controller designated discharge destination to J, and the change destination designation to P.

[0083] 18 and 19 are flowcharts showing the flow of the process performed by the printing device when setting a changed discharge destination. The process shown in FIG. 18 and FIG. 19 is executed by the CPU 222 of the printing device 107. When the CPU 222 determines that the printing device 107 has not received a stop instruction (NO in step S12), it receives a print instruction from the external controller 102 (step S73). This corresponds to the case where the external controller 102 issues a print instruction to the printing device 107 in step S72 shown in FIG. 17. The CPU 222 assigns the discharge destination buffer A to the discharge destination K (step S17) or assigns the discharge destination designation Y to the discharge destination K (step S18), and prints the image formation job received from the external controller 102 (step S74). At this time, the CPU 222 designates the discharge destination designation as Y, the changed destination designation as P, and the discharge destination as K, and conveys the image formation job to the inspection device 108.

[0084] 20 and 21 are flowcharts showing the flow of the process performed by the inspection device 108 when setting a new discharge destination. The process shown in FIG. 20 and FIG. 21 is executed by the CPU 233 of the inspection device 108. When the CPU 233 determines that the specified discharge destination K is waiting for recovery (YES in step S44), it determines whether the specified discharge destination K is not equal to the change destination designation P and whether the change destination designation P is not "not changed" (step S75). When the CPU 233 determines that the specified discharge destination K is not equal to the change destination designation P and whether the change destination designation P is not "not changed" (YES in step S75), it changes the discharge destination K to the change destination designation P designated in FIG. 16 (step S76). When the CPU 233 determines that the specified discharge destination K is equal to the change destination designation P and / or the change destination designation P is "not changed" (NO in step S75), it notifies the first stacker 111 of inspection NG discharge (step S40).

[0085] In this way, when "second stack tray" is selected by the button 403 on the screen shown in FIG. 16 (first mode), the following steps are executed. That is, the determination step, the first normal discharge step, the first abnormal discharge step, the second abnormal discharge step, the second normal discharge step, the complement step, and the first recovery step are executed. On the other hand, when "no change" is selected by the button 403 on the screen shown in FIG. 16 (second mode), the determination step, the first normal discharge step, the first abnormal discharge step, the third abnormal discharge step, and the second recovery step are executed. Here, the third abnormal discharge step is a step of discharging the remaining sheets to the escape tray 334 when it is determined that the image read by the inspection device 108 in the determination step is an abnormal image. In addition, in the second recovery step, for the sheets on which images have been formed by the printing device 107 from the abnormal sheet to the final sheet of the first copy, image formation by the printing device 107 is executed again, and then the sheets on which images have been formed are discharged to the first stack tray 331. Furthermore, in the second recovery process, for sheets on which images have been formed by the printing device 107 in the copies following the first copy, after image formation is performed by the printing device 107, the sheets on which images have been formed are discharged to the first stack tray 331.

[0086] As described above, according to the image forming apparatus 101 of this embodiment, the first mode and the second mode can be selected. Therefore, for example, when productivity is not a priority, only the first stack tray 331 may be used, thereby increasing the freedom of usage.

[0087] In the above-described control method for the image forming apparatus 101 of the present embodiment, the determination step, the first normal discharge step, the first abnormal discharge step, the third abnormal discharge step, and the second recovery step are executed in the second mode, but the present invention is not limited to this. For example, it is sufficient to include at least the determination step, the first normal discharge step, the first abnormal discharge step, and the third abnormal discharge step.

[0088] In the above-described embodiments, the first stack tray 331 and the second stack tray 341 are used as the discharge destinations for normal sheets, but the present invention is not limited to this, and three or more discharge destinations may be used. In this case, even if two of the three discharge destinations are on standby for recovery, the sheets can be discharged to the remaining one, thereby further improving productivity. [Explanation of symbols]

[0089] 101...image forming apparatus, 107...printing apparatus (image forming section), 108...inspection device (reading section), 212...display (display section), 233...CPU (control section), 323...sheet transport path (transport section), 331...first stack tray (first discharge section), 334...escape tray (second discharge section), 341...second stack tray (third 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, a second discharge section, and a third discharge section to which the sheet conveyed by the conveying section is selectively discharged; a control unit that compares the image read by the reading unit with image information to determine whether the image is normal or abnormal, and selects a discharge destination for discharging the sheet from among the first discharge unit, the second discharge unit, and the third discharge unit; The control unit is When an image forming job is executed in which one copy is made up of a plurality of sheets and the plurality of copies are continuously image-formed, When 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; 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, sheets constituting a first set including the abnormal sheet are discharged to the second discharge section; Among the remaining sheets, sheets that do not constitute the first portion are discharged to the third discharge section.

1. An image forming apparatus comprising:

2. The control unit is In a second section including the last sheet among the remaining sheets, for a sheet on which image formation by the image forming section has not been performed at the time when the abnormal image is read, after performing image formation by the image forming section, the sheet on which the image has been formed is discharged to the third discharge section; and performing image formation again on the sheets constituting the first section from the abnormal sheet to the final sheet of the first section by the image forming section, and then discharging the sheets on which the images have been formed to the first discharge section.

2. The image forming apparatus according to claim 1,

3. The control unit is image formation for sheets on which image formation by the image forming unit has not been performed at the time when the abnormal image in the second part is read is performed prior to re-execution of image formation for sheets constituting the first part from the abnormal sheet to the final sheet of the first part.

3. The image forming apparatus according to claim 2,

4. The control unit is image formation for sheets on which image formation by the image forming unit has not been performed at the time when the abnormal image in the second part is read is performed after re-execution of image formation for sheets constituting the first part from the abnormal sheet to the final sheet of the first part.

3. The image forming apparatus according to claim 2,

5. 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, a second discharge section, and a third discharge section to which the sheet conveyed by the conveying section is selectively discharged; a control unit that compares the image read by the reading unit with image information to determine whether the image is normal or abnormal, and selects a discharge destination for discharging the sheet from among the first discharge unit, the second discharge unit, and the third discharge unit; the control unit selectively executes, with respect to a discharge unit that discharges a sheet on which a normal image is formed when an image read by the reading unit is a normal image, a first mode in which the first discharge unit and the third discharge unit are selectively used, and a second mode in which the first discharge unit is used without using the third discharge unit; In the first mode, 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, sheets constituting a first set including the abnormal sheet are discharged to the second discharge section; Among the remaining sheets, sheets that do not constitute the first portion are discharged to the third discharge section; In the second mode, If the image read by the reading unit is an abnormal image, the abnormal sheet on which the abnormal image is formed and the remaining sheet are discharged to the second discharge unit.

1. An image forming apparatus comprising:

6. The control unit is In the first mode, In a second section including the last sheet among the remaining sheets, for a sheet on which image formation by the image forming section has not been performed at the time when the abnormal image is read, after performing image formation by the image forming section, the sheet on which the image has been formed is discharged to the third discharge section; With respect to the sheets constituting the first section from the abnormal sheet to the final sheet of the first section, image formation is performed again by the image forming section, and then the sheets on which the images have been formed are discharged to the first discharge section; In the second mode, With respect to the sheets constituting the first section from the abnormal sheet to the final sheet of the first section, image formation is performed again by the image forming section, and then the sheets on which the images have been formed are discharged to the first discharge section; and for sheets of the next set after the first set, after performing image formation by the image forming unit, discharging the image-formed sheets to the first discharge unit.

6. The image forming apparatus according to claim 5,

7. A display unit capable of displaying information is provided, When a destination to which the sheet is discharged is changed among the first discharge unit, the second discharge unit, and the third discharge unit, the display unit displays a message indicating that the destination has been changed.

7. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

8. 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, a second discharge section, and a third discharge section to which the sheet conveyed by the conveying section is selectively discharged; a control unit that compares an image read by the reading unit with image information to determine whether the image is normal or abnormal, and selects a discharge destination for discharging a sheet from among the first discharge unit, the second discharge unit, and the third discharge unit, When an image forming job is executed in which one copy is made up 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 sheets constituting a first set 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, to the second discharge section; and a second normal discharge step of discharging sheets that do not constitute the first portion, among the remaining sheets, to the third discharge section. 2 is a control method for an image forming apparatus according to claim 1 .

9. a complementing step of, for a sheet on which image formation has not been performed by the image forming unit at the time when the abnormal image is read in a second section including the last sheet of the remaining sheets, performing image formation by the image forming unit and then discharging the image-formed sheet to the third discharge section; a first recovery step of performing image formation again by the image forming unit on the sheets from the abnormal sheet constituting the first part to the final sheet of the first part, and then discharging the image-formed sheets to the first discharge unit; 9. The method for controlling an image forming apparatus according to claim 8.

10. After executing the complementation step, execute the first recovery step.

10. The method for controlling an image forming apparatus according to claim 9.

11. After performing the first recovery step, perform the complement step.

10. The method for controlling an image forming apparatus according to claim 9.

12. 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, a second discharge section, and a third discharge section to which the sheet conveyed by the conveying section is selectively discharged; a control unit that compares an image read by the reading unit with image information to determine whether the image is normal or abnormal, and selects a discharge destination for discharging a sheet from among the first discharge unit, the second discharge unit, and the third discharge unit, When an image forming job is executed in which one copy is made up of a plurality of sheets and the plurality of copies are continuously image-formed, a discharge section for discharging a sheet on which a normal image is formed when the image read by the reading section is a normal image, selectively executing a first mode in which the first discharge section and the third discharge section are selectively used, and a second mode in which the first discharge section is used without using the third discharge section; In the first mode, 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 sheets constituting a first set 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, to the second discharge section; a second normal discharge step of discharging sheets that do not constitute the first portion out of the remaining sheets to the third discharge section; In the second mode, The determination step; The first normal discharge step; The first abnormality discharge step; a third abnormality discharge step of discharging the remaining sheet to the second discharge section when it is determined in the determination step that the image read by the reading section is an abnormal image. 2 is a control method for an image forming apparatus according to claim 1 .

13. In the first mode, a complementing step of, for a sheet on which image formation has not been performed by the image forming unit at the time when the abnormal image is read in a second section including the last sheet of the remaining sheets, performing image formation by the image forming unit and then discharging the image-formed sheet to the third discharge section; a first recovery step of performing image formation again by the image forming unit for the sheets from the abnormal sheet constituting the first part to the final sheet of the first part, and then discharging the image-formed sheets to the first discharge unit; In the second mode, a second recovery step is performed in which, for sheets constituting the first part from the abnormal sheet to the final sheet of the first part, image formation is performed again by the image forming unit, and the image-formed sheets are discharged to the first discharge part; and, for sheets of the next part and subsequent parts of the first part, image formation is performed by the image forming unit, and the image-formed sheets are discharged to the first discharge part. The method for controlling an image forming apparatus according to claim 12 .

14. the image forming apparatus includes a display unit capable of displaying information; a change display step of displaying a change to the destination of the sheet discharged from among the first discharge unit, the second discharge unit, and the third discharge unit, 14. The method for controlling an image forming apparatus according to claim 8,

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