Patent Description:
In recent years, there has been known an image forming system configured such that an image is formed on a sheet by a printing apparatus, and the sheet on which the image is formed is conveyed to an inspection apparatus connected to the printing apparatus for inspection. When an image is formed on a sheet by a printing apparatus and the sheet is inspected by an inspection apparatus connected to the printing apparatus, this inspection method is hereinafter referred to as an inline inspection. In the inline inspection, the inspection apparatus reads an image formed by the printing apparatus on a sheet, and determines whether the image on the sheet is normal. The inspection apparatus can detect, for example, a partially or entirely missing barcode or ruled line, a missing image, defective printing, a missing page, a color shift, and/or the like.

<CIT> discloses that when a sheet on which an image has been formed is determined to be an abnormal sheet, this abnormal sheet is discharged to a discharge unit different from that to which normal sheets are discharged, and a correct image corresponding to the image formed on the abnormal sheet is printed on another sheet (this process is referred to as a recovery process). This makes it possible to prevent a final product from missing a page even when an abnormal sheet occurs.

It is also known to inspect a sheet in a process which, unlike the inline inspection, does not include printing using a printing apparatus. Such an inspection method is hereinafter referred to as offline inspection. In the offline inspection, it is possible to inspect sheets on which images have been previously formed by a printing apparatus which is not connected to the inspection apparatus.

<CIT> discloses an image forming system capable of performing an offline inspection in addition to an inline inspection. This makes it possible to inspect sheets even in a situation in which only one of image forming systems used by a user has a connected inspection apparatus, such that after images are formed on sheets by an image forming system having no connected inspection apparatus, the sheets are inspected by the image forming system having the capability of the offline inspection.

However, in the image forming system disclosed in <CIT>, no consideration is given to performing a recovery process when an abnormal sheet occurs in the inline inspection or the offline inspection. Therefore, in the image forming system capable of performing both the inline inspection and the offline inspection, there is a desire for improvement in processing when an abnormal sheet occurs.

<CIT> discloses an image forming system.

<CIT> discloses an inspection device, image forming system and sheet conveying device.

<CIT> discloses a print system and print control method. <CIT> discloses an image forming system, and a control method thereof.

In view of the above, the present disclosure provides improved processing executable for a case where an abnormal sheet occurs in an image forming system capable of performing both the inline inspection and the offline inspection. An abnormal sheet having abnormality in the image formed on the sheet may be determined by inspecting the image of the sheet in terms of predetermined inspection items. The inspection of the image of the sheet may be performed by an inspection means comparing, with respect to one or more inspection items associated with an image, the image of the sheet with a preregistered or predetermined correct answer image stored in the image forming system. The inspection items may be user selectable and/or may include misalignment of a printing position, a color tone of an image, a density of an image, a streak or blurring, a missing of printing, and/or the like.

The present invention in its first aspect provides an image forming system as specified in claims <NUM> to <NUM>.

The present invention in its second aspect provides an image forming system as specified in claims <NUM> and <NUM>.

The present invention in its third aspect provides a method of controlling an image forming system as specified in claim <NUM>. Further aspects of the invention are defined by claims <NUM> and <NUM>.

Embodiments of the present disclosure are described in detail below with reference to the drawings. It should be noted that the embodiments described below are examples that embody the present disclosure, and the technical scope of the present disclosure is not limited to these examples.

<FIG> is a diagram illustrating an overall hardware configuration of an image forming system according to a first embodiment. The image forming system includes an image forming apparatus <NUM> and an external controller <NUM>. The image forming apparatus <NUM> and the external controller <NUM> are communicably connected to each other via an internal LAN <NUM> and a video cable <NUM>. The external controller <NUM> is communicably connected to a PC <NUM> via an external LAN <NUM>. The PC <NUM> issues a print instruction to the external controller <NUM>.

In the PC <NUM>, a printer driver is installed which has a function of converting print data into a print description language that can be processed by the external controller <NUM>. A user who performs printing is allowed to give a print instruction from various applications via the printer driver. The printer driver transmits print data to the external controller <NUM> based on a print instruction from the user. When the external controller <NUM> receives the print instruction from the PC <NUM>, the external controller <NUM> performs data analysis and rasterization processing, inputs the print data to the image forming apparatus <NUM>, and instructs it to perform printing.

The image forming apparatus <NUM> includes a printing apparatus <NUM>, an inserter <NUM>, an inspection apparatus <NUM>, and a large-capacity stacker <NUM>. The printing apparatus <NUM>, which is an image forming unit (also referred to as image forming means), forms an image on a sheet based on an instruction given from the external controller <NUM>. The inserter <NUM>, which is a conveyance unit (also referred to as conveyance means), inserts an insertion sheet between a plurality of sheets conveyed from the printing apparatus <NUM>. The inspection apparatus <NUM>, which is an inspection unit (also referred to as inspection means), reads an image of a conveyed sheet and compares it with a pre-registered correct answer image to determine whether or not the image of the sheet is normal. Here, the correct answer image is an image represented by image data to be compared with a sheet by the inspection apparatus <NUM>. The image data of the correct answer image is prepared by the image forming apparatus <NUM> by reading a correctly printed sheet. The image data of the correct answer image may be sent from the PC <NUM>. In the following description, a sheet determined to be normal (good) by the inspection apparatus <NUM> is referred to as a normal sheet, and a sheet determined to be abnormal (not good) by the inspection apparatus <NUM> is referred to as an abnormal sheet. For example, following a comparison by the inspection apparatus <NUM> of the image of a conveyed sheet with a corresponding pre-registered correct answer image (e.g. a predetermined image representing a correct image and which predetermined image is stored in the inspection apparatus <NUM> for comparing with an image of a subsequent conveyed sheet) using an image comparison method (examples of which are discussed below), when the inspection apparatus <NUM> determines that the image of a conveyed sheet matches substantially the corresponding pre-registered correct answer image (e.g. the differences between the images are minor/insignificant which may depend on the inspection level set which determines the sensitivity of the comparison), the sheet with the image is determined to be a normal sheet (e.g. correct or good) having a normal image and when the inspection apparatus <NUM> determines that the image of a conveyed sheet does not match the corresponding pre-registered correct answer image (e.g. the differences between the images are significant which may depend on the inspection level set which determines the sensitivity of the comparison), the sheet with the image is determined to be an abnormal sheet (not good) having abnormality in the image. The comparison may be made with respect to one or more inspection items associated with an image as described in more detail below. The large-capacity stacker <NUM> is a stacker with a large capacity for loading conveyed sheets in a stacked manner.

In the image forming system according to the present embodiment, the external controller <NUM> is connected to the image forming apparatus <NUM>, but this is merely an example. The image forming system is not limited to this configuration in which the external controller <NUM> is connected to the image forming apparatus <NUM>. For example, the image forming apparatus <NUM> may be connected to the external LAN <NUM>, and the print data that can be processed by the image forming apparatus <NUM> may be transmitted from the PC <NUM>.

In this case, the image forming apparatus <NUM> performs data analysis and rasterization processing, and executes printing processing.

<FIG> is a block diagram showing a system configuration of the image forming apparatus <NUM>, the external controller <NUM>, and the PC <NUM>. First, the configuration of the printing apparatus <NUM> of the image forming apparatus <NUM> is described. The printing apparatus <NUM> includes a communication I/F <NUM>, a LAN I/F <NUM>, a video I/F <NUM>, an HDD <NUM>, a CPU <NUM>, a memory <NUM>, an operation unit <NUM>, and a display <NUM>. Furthermore, the printing apparatus <NUM> also includes a document exposure unit <NUM>, a laser exposure unit <NUM>, an image forming unit <NUM>, a fixing unit <NUM>, and a sheet feeding unit <NUM>. The components of the printing apparatus <NUM> are connected to each other via a system bus <NUM>. The communication I/F <NUM> is connected to the inserter <NUM>, the inspection apparatus <NUM>, and the large-capacity stacker <NUM> via a communication cable <NUM>, and communicates for control of each apparatus. The LAN I/F <NUM> is connected to the external controller <NUM> via the internal LAN <NUM> and communicates in terms of print data and the like. The video I/F <NUM> is connected to the external controller <NUM> via the video cable <NUM> and communicates image data and the like. HDD <NUM> is a storage apparatus in which a program and data are stored. The CPU <NUM> comprehensively controls image processing and printing based on a program or the like stored in the HDD <NUM>. The memory <NUM> stores a program, image data, and/or the like and functions as a work area used by the CPU <NUM> in executing various kinds of processing. The operation unit <NUM> accepts inputs of various settings and operation instructions from a user. The display <NUM> displays setting information of the image processing apparatus, a processing state of a print job, and the like.

The document exposure unit <NUM> performs a process of reading a document when the copy function or the scan function is used. More specifically, the image is read by capturing an image by a CCD reading unit while illuminating a sheet placed by a user with an exposure lamp. The laser exposure unit <NUM> is an apparatus that performs primary charging and laser exposure, for irradiating a photosensitive drum with laser light to transfer a toner image. The laser exposure unit <NUM> first performs primary charging to charge the surface of the photosensitive drum to a uniform negative potential. Next, a laser driver illuminates the photosensitive drum with laser light while controlling the reflection angle of a laser beam from a polygon mirror. As a result, an electrostatic latent image is formed on the photosensitive drum. The image forming unit <NUM> is an apparatus for transferring toner to the sheet, and includes a developing unit, a transfer unit, a toner replenishing unit, and the like thereby transferring the toner on the photosensitive drum to the sheet. The developing unit supplies negatively charged toner from a developing cylinder to the photosensitive drum such that the negatively charged toner sticks to the electrostatic latent image on the surface of the photosensitive drum whereby the latent image is visualized. The transfer unit performs primary transferring by applying a positive potential to a primary transfer roller and transferring the toner on the surface of the photosensitive drum to a transfer belt. Furthermore, the transfer unit performs secondary transferring by applying a positive potential to a secondary transfer outer roller and transferring the toner on the transfer belt to the sheet. The fixing unit <NUM> is an apparatus for melting and fixing the toner on the sheet by heat and pressure, and includes a heater, a fixing belt, a pressure belt, and the like. The sheet feeding unit <NUM> is an apparatus for feeding a sheet. A sheet feeding operation and a sheet conveying operation are controlled by rollers and various sensors.

Next, the configuration of the inserter <NUM> of the image forming apparatus <NUM> is described. The inserter <NUM> includes a communication I/F <NUM>, a CPU <NUM>, a memory <NUM>, and a sheet feed control unit <NUM>. These components are connected via a system bus <NUM>. The communication I/F <NUM> is connected to the printing apparatus <NUM> via a communication cable <NUM>, and performs communication necessary for controlling the inserter <NUM>. The CPU <NUM> performs various controls necessary for the sheet feeding process according to a control program stored in the memory <NUM>. The memory <NUM> is a storage apparatus in which the control program is stored. The sheet feed control unit <NUM> controls conveying of a sheet fed from the sheet feeding unit <NUM> (also referred to as sheet feed tray) of the inserter <NUM> or from the printing apparatus <NUM> while controlling the rollers and the sensors under the control of the CPU <NUM>.

Next, the configuration of the inspection apparatus <NUM> of the image forming apparatus <NUM> is described. The inspection apparatus <NUM> includes a communication I/F <NUM>, a CPU <NUM>, a memory <NUM>, an imaging unit <NUM>, a display <NUM>, and an operation unit <NUM>. These components are connected via a system bus <NUM>. The communication I/F <NUM> is connected to the printing apparatus <NUM> via the communication cable <NUM> and performs communication necessary for controlling the inspection apparatus <NUM>. The CPU <NUM> performs various controls necessary for the inspection according to a control program stored in the memory <NUM>. The memory <NUM> is a storage apparatus in which the control program is stored. The imaging unit <NUM> captures an image of a sheet conveyed to the printing apparatus <NUM> based on an instruction given by the CPU <NUM>. The CPU <NUM> compares the image captured by the imaging unit <NUM> with the correct answer image stored in the memory <NUM>, and determines whether or not the printed image is correct. The display <NUM> displays an inspection result, a setting screen, and/or the like. The operation unit <NUM> is operated by the user and accepts instructions such as an instruction to change a setting of the inspection apparatus <NUM>, an instruction to register a correct answer image, and/or the like.

Next, the configuration of the large-capacity stacker <NUM> of the image forming apparatus <NUM> is described. The large-capacity stacker <NUM> includes a communication I/F <NUM>, a CPU <NUM>, a memory <NUM>, and a sheet discharge control unit <NUM>, in which these components are connected via a system bus <NUM>. The communication I/F <NUM> is connected to the printing apparatus <NUM> via a communication cable <NUM>, and performs communication necessary for controlling the large-capacity stacker <NUM>. The CPU <NUM> performs various controls necessary for discharging a sheet according to a control program stored in the memory <NUM>. The memory <NUM> is a storage apparatus in which the control program is stored. Under the control of the CPU <NUM>, the sheet discharge control unit <NUM> controls conveying of a sheet from the large-capacity stacker <NUM> to a stack tray <NUM> or an escape tray <NUM>.

Next, the configuration of the external controller <NUM> is described. The external controller <NUM> includes a CPU <NUM>, a memory <NUM>, an HDD <NUM>, a keyboard <NUM>, a display <NUM>, a LAN I/F <NUM>, a LAN I/F <NUM>, and video I/F <NUM>. The components of the external controller <NUM> are connected via a system bus <NUM>. The CPU <NUM> comprehensively executes processing such as receiving of print data from the PC <NUM>, RIP processing, and transmitting of print data to the image forming apparatus <NUM> based on a program and data stored in the HDD <NUM>. The memory <NUM> stores a program, image data, and/or the like and functions as a work area used by the CPU <NUM> in executing various kinds of processing. The HDD <NUM> stores programs and data necessary for operations such as printing processing. The keyboard <NUM> is an apparatus for inputting an operation instruction to the external controller <NUM>. The display <NUM> displays information related to an execution application of the external controller <NUM> in the form of a still image or a moving image according to a video signal. The LAN I/F <NUM> is connected to the PC <NUM> via the external LAN <NUM>, and the LAN I/F <NUM> performs communication related to a print instruction and/or the like. The LAN I/F <NUM> is connected to the image forming apparatus <NUM> via the internal LAN <NUM>. The LAN I/F <NUM> performs communication related to a print instruction and/or the like. The video I/F <NUM> is connected to the image forming apparatus <NUM> via the video cable <NUM>. The video I/F <NUM> performs communication relating to a print data and/or the like.

Next, a configuration of the PC <NUM> is described below. The PC <NUM> includes a CPU <NUM>, a memory <NUM>, an HDD <NUM>, a keyboard <NUM>, a display <NUM>, and a LAN I/F <NUM>. These components are connected to each other via a system bus <NUM>. The CPU <NUM> generates print data and executes a print instruction based on a document processing program or the like stored in the HDD <NUM>. Furthermore, the CPU <NUM> comprehensively controls devices connected to the system bus. The memory <NUM> stores a program, image data, and/or the like and functions as a work area used by the CPU <NUM> in executing various kinds of processing. The HDD <NUM> stores programs and data necessary for operations such as printing processing. The keyboard <NUM> is an apparatus for inputting an operation instruction to the PC <NUM>. The display <NUM> displays information related to an execution application of the PC <NUM> in the form of a still image or a moving image according to a video signal. The LAN I/F <NUM> is connected to the external controller <NUM> via the external LAN <NUM>. The LAN I/F <NUM> performs communication related to a print instruction and/or the like.

In the example described above, the external controller <NUM> and the image forming apparatus <NUM> are connected to each other via the internal LAN <NUM> and the video cable <NUM>. However, other configurations are possible as long as data necessary for printing can be transmitted and received. For example, the external controller <NUM> and the image forming apparatus <NUM> may be connected to each other only via the video cable. The memory <NUM>, the memory <NUM>, the memory <NUM>, the memory <NUM>, the memory <NUM>, and the memory <NUM> each may be any type of storage apparatus capable of storing data, programs, and/or the like. The types usable for them include, for example, a volatile RAM, a non-volatile ROM, an internal HDD, an external HDD, and a USB memory.

Next, the image forming apparatus <NUM> is described below with reference to <FIG> is a schematic cross-sectional view of the image forming apparatus <NUM>. The printing apparatus <NUM> includes sheet feed decks <NUM> and <NUM>. Various sheets are loaded on the sheet feed decks <NUM> and <NUM>. The sheet feed decks <NUM> and <NUM> are each capable of separating only one uppermost sheet from stacked sheets and conveying it to the sheet conveyance path <NUM>. Development stations <NUM> to <NUM> form toner images using colored toners of Y, M, C, and K, respectively, so as to form a color image. The toner images formed by the development stations <NUM> to <NUM> are primarily transferred to an intermediate transfer belt <NUM>. The intermediate transfer belt <NUM> rotates clockwise in <FIG>, and the toner image is transferred, at a secondary transfer position <NUM>, to a sheet transferred from the sheet conveyance path <NUM>. The display <NUM> displays information related to the print status and settings of the image forming apparatus <NUM>. A first fixing unit <NUM> includes a pressure roller and a heating roller and operates such that when the sheet passes between the rollers, the toner is melt while being pressed thereby fixing the toner image on the sheet. After the sheet is passed through the first fixing unit <NUM>, the sheet is conveyed to the inserter <NUM> along sheet conveyance paths <NUM> and <NUM>. Depending on the type of the sheet, further melting and pressing may be necessary. In such a case, after the sheet is passed through the first fixing unit <NUM>, the sheet is conveyed to a second fixing unit <NUM> via an upper sheet conveyance path and additional melting and pressing is performed by the second fixing unit <NUM>. Thereafter, the sheet is conveyed to the inserter <NUM> via sheet conveyance path paths <NUM> and <NUM>. In a case where it is specified that an image is formed on both sides of the sheet, the sheet is inverted by a sheet inversion path <NUM> and conveyed to a double-sided conveyance path <NUM>, and an image is transferred to the second surface at a secondary transfer position <NUM>.

The inserter <NUM> inserts an insertion sheet between sheets conveyed from the printing apparatus <NUM>. The inserter <NUM> includes an inserter tray <NUM> that functions as a sheet feed tray, and operates to join sheets such that the insertion sheet fed from the inserter tray <NUM> via the sheet conveyance path <NUM> is joined with sheets conveyed by a sheet conveyance path <NUM>. Thus, the inserter <NUM> is capable of inserting an insertion sheet, at any specified position, between sheets conveyed from the printing apparatus <NUM>. Note that the inserter <NUM> is also capable of conveying a sheet to the inspection apparatus <NUM> by feeding the sheet from the inserter tray <NUM> regardless of the printing operation. That is, the inserter <NUM> is capable of conveying, to the inspection apparatus <NUM>, both a sheet that is image-formed and discharged by the printing apparatus <NUM> and a sheet that is different from the sheet that is image-formed and discharged by the printing apparatus <NUM> (e.g. the inserter <NUM> is capable of conveying, to the inspection apparatus <NUM>, a sheet on which an image has been previously formed (such as by the image forming unit <NUM> or by another image forming unit <NUM>) and which has not been conveyed from the image forming unit <NUM> as part of performing a print job and so is conveyed to the inspection apparatus as part of a job without executing image forming by the image forming unit <NUM> having been previously performed).

The inspection apparatus <NUM> reads the image of the sheet conveyed through the sheet conveyance path <NUM> of the inserter <NUM>, and determines whether or not the images of the sheet are normal (for example, by performing a comparison with a predetermined correct answer image as discussed above). Reading units <NUM> and <NUM> are disposed inside the inspection apparatus <NUM> so as to face each other. The reading unit <NUM> reads the image on the first side of the sheet, and the reading unit <NUM> reads the image on the second side, opposite to the first side, of the sheet. The inspection apparatus <NUM> performs the inspection such that when the sheet conveyed via a sheet conveyance path <NUM> reaches a predetermined position, the images of the sheet are read using the reading units <NUM> and <NUM>, and a determination is made as to whether or not the images of the sheet are normal. The display <NUM> displays information regarding a result of the inspection performed by the inspection apparatus <NUM>.

The large-capacity stacker <NUM> includes, as a first discharge unit (also referred to as a first discharge portion) for discharging sheets, the stack tray <NUM> including a lift table and an eject table. The large-capacity stacker <NUM> has a shift function of discharging a sheet, on the stack tray <NUM>, to a position shifted by a predetermined amount from other sheets. The sheet that has passed through the inspection apparatus <NUM> is conveyed to the large-capacity stacker <NUM> via the sheet conveyance path <NUM>. The sheet is conveyed via a sheet conveyance path <NUM> and further via a sheet conveyance path <NUM>, and stacked on the lift table of the stack tray <NUM>. When no sheet is loaded on the lift table, the lift table stands by at a top position. The lift table is controlled such that the lift table is lowered as the sheets are loaded, and the upper end of the bundle of stacked sheets is at a predetermined height. When the loading of the sheets is completed or when the lift table is fully loaded, the lift table is lowered to the position of an eject table. The lift table and the eject table are configured such that bars supporting the sheet bundle are located at staggered positions. Therefore, when the lift table descends until reaching a position lower than the eject table, the sheet bundle comes into a state in which the sheet bundle is transshipped to the eject table.

The large-capacity stacker <NUM> also include, as a second discharge unit (also referred to as a first discharge portion), an escape tray <NUM> for discharging a sheet. The escape tray <NUM> operates such that when the inspection apparatus <NUM> determines that a sheet is abnormal (as discussed above), this abnormal sheet is discharged onto the escape tray <NUM>. In a case where the abnormal sheet is discharged to the escape tray <NUM>, the abnormal sheet is conveyed via the sheet conveyance path <NUM> and further via a sheet conveyance path <NUM>, and conveyed to the stack tray <NUM>. In a case where a post-processing apparatus is connected to the downstream side of the large-capacity stacker <NUM>, the sheet is conveyed to the post-processing apparatus via a sheet conveyance path <NUM>. The large-capacity stacker <NUM> includes an inversion unit <NUM> for inverting a sheet between the front and back sides of the sheet. The inversion unit <NUM> is used when the sheet is stacked on the stack tray <NUM>. In a case where the large-capacity stacker <NUM> conveys the sheet to the escape tray <NUM> or the subsequent post-processing apparatus, the inversion unit <NUM> does not perform the inversion operation.

<FIG> each illustrate an example of a screen displayed on the display <NUM> of the inspection apparatus <NUM>. The inspection apparatus <NUM> inspects the image of the sheet conveyed to the inspection apparatus <NUM> in terms of predetermined inspection items. The inspection of the image of the sheet is performed by comparing the image of the sheet read by the reading unit <NUM> or <NUM> with a correct answer image registered in the memory <NUM> in advance. Image comparison methods include a method of comparing pixel values for each image position, a method of comparing positions of objects by edge detection, and a method of extracting character data by OCR (Optical Character Recognition). The inspection items include misalignment of a printing position, a color tone of an image, a density of an image, a streak or blurring, a missing of printing, and/or the like. In the present embodiment, each button displayed on the display <NUM> and the display <NUM> is a soft key that a user is allowed to touch with a finger for selection.

<FIG> illustrates an example of a display screen displayed on the display <NUM> of the inspection apparatus <NUM> when the inspection apparatus <NUM> is started. In the example of the display screen shown in <FIG>, the display <NUM> indicates that no correct answer image is registered, and thus a message is displayed to inform that a correct answer image needs to be registered to start the inspection. In a case where the correct answer image has already been registered, a message is displayed to inform that the inspection can be started. On the display <NUM>, a registered correct answer image is displayed in an image display area <NUM>. In the example shown in <FIG>, a message indicating that no correct answer image is registered is displayed in the image display area <NUM>. A button <NUM> is for opening a registration screen for registering the correct answer image. A button <NUM> is for opening an inspection setting screen. A button <NUM> is for opening a screen for confirming an inspection result. A button <NUM> is for instructing to start an instruction.

<FIG> illustrates an example of a display screen displayed on the display <NUM> of the inspection apparatus <NUM> when a user registers a correct answer image. The display screen shown in <FIG> is displayed on the display <NUM> when the button <NUM> shown in <FIG> is selected. A number-of-sheet setting area <NUM> is used to set the number of sheets per copy in a print job for which the inspection is to be performed. In a case of a print job in which the number of sheets per copy is two or more, it is allowed to register a plurality of images as correct answer images in the inspection apparatus <NUM>. A side setting area <NUM> is for setting a side of a sheet to be inspected by the inspection apparatus <NUM>. The user is allowed to set via the side setting area <NUM> whether to inspect the images on both sides of the sheet, only the image on the front side, or only the image on the back side. Even in a case where printing is performed on only one side of the sheet, it is possible to set that both sides are to be inspected to determine whether or not dust or the like is attached to the non-printed side. A button <NUM> is for instructing to register a correct answer image. When the button <NUM> is selected, the inspection apparatus <NUM> reads the image of the conveyed sheet and registers the image data thereof as data of a correct answer image.

<FIG> illustrates an example of a display screen displayed on the display <NUM> when the inspection apparatus <NUM> is reading an image of a sheet to register a correct answer image. The display screen shown in <FIG> is displayed when the button <NUM> shown in <FIG> is selected. A button <NUM> is for instructing to stop a reading process. In a case where the button <NUM> is selected, the inspection apparatus <NUM> stops the image reading process, and the screen displayed on the display <NUM> returns to the display screen shown in <FIG>.

<FIG> illustrates an example of a display screen displayed on the display <NUM> when reading of a correct answer image is completed. The image of the sheet read by the inspection apparatus <NUM> is displayed in an image display area <NUM>. In a case where there are a plurality of images, it is possible to switch the displayed image by operating a switching button <NUM>. In a case where both sides are to be inspected, the displayed side can be switched between front and back sides by operating a switching button <NUM>. A button <NUM> is for instructing to set an inspection skip area. Using the button <NUM>, it is possible to set an area that is not inspected, for example, in variable data printing (VDP) or the like in which a content of printing in a specific area is varied copy by copy. A button <NUM> is for registering the image displayed in the image display area <NUM> as a correct answer image. When the button <NUM> is selected, the inspection apparatus <NUM> registers the correct answer image, and the screen returns to the display screen shown in <FIG>. A button <NUM> is for canceling the reading. When the button <NUM> is pressed, the inspection apparatus <NUM> returns the screen of the display <NUM> to that shown in <FIG> without registering the correct answer image.

<FIG> illustrates an example of a screen, displayed on the display <NUM>, for setting an inspection skip area. The display screen shown in <FIG> is displayed on the display <NUM> when the button <NUM> is selected. An area <NUM> indicates an inspection skip area. The user is allowed to change the position of the area <NUM> by using a position setting buttons <NUM>, and is allowed to change the size of the area <NUM> by using size setting buttons <NUM>. A button <NUM> is for registering settings of the inspection skip area. When the button <NUM> is selected, the inspection apparatus <NUM> registers the area <NUM> as an inspection skip area, and the screen displayed on the display <NUM> returns to the display screen shown in <FIG>. A button <NUM> is for further registering another inspection skip area. By this button <NUM>, the inspection apparatus <NUM> can register a plurality of inspection skip areas for one piece of image data. A button <NUM> is for cancelling the settings of the inspection skip area.

When the button <NUM> is selected, the screen displayed on the display <NUM> returns to the display screen shown in <FIG>.

<FIG> illustrates an example of an inspection setting screen. The display screen shown in <FIG> is displayed on the display <NUM> when the button <NUM> is selected. A level setting area <NUM> is used to set an inspection level. The higher the inspection level set by the level setting area <NUM>, the higher the sensitivity of the inspection apparatus <NUM> to a difference between an image being inspected and a correct answer image. An inspection item setting area <NUM> is used to set inspection items. The user is allowed to set inspection items in the inspection item setting area <NUM>. In the example shown in <FIG>, the inspection item setting area <NUM> displayed on the display screen is in a state where a position, a color, a streak, and missing are set to be inspected, but the density is set not to be inspected. A button <NUM> is for confirming the settings of the inspection items. When the button <NUM> is selected, the inspection apparatus <NUM> registers the settings of the inspection items, and the screen displayed on the display <NUM> returns to the display screen shown in <FIG>.

<FIG> illustrates an example of a display screen on which inspection results are displayed. The display screen shown in <FIG> is displayed on the display <NUM> when the button <NUM> shown in <FIG> is selected. A property display area <NUM> is for displaying properties and inspection results of a job subjected to the inspection. In a result display area <NUM>, inspection results are displayed for each sheet. The results are displayed in the result display area <NUM> such that when a sheet read by the inspection apparatus <NUM> is determined to be normal, "OK" is displayed in a result field corresponding to this sheet, but in a case where a sheet read by the inspection apparatus <NUM> is determined to be abnormal, "NOT GOOD" is displayed in a result field corresponding to this sheet. A button <NUM> is for selecting a job for which inspection results are displayed. In the example of the display screen shown in <FIG>, the inspection results for the 1st one of <NUM> jobs stored in the inspection apparatus <NUM> are displayed. By operating the left or right end of button <NUM>, the user is allowed to switch the job for which the inspection results are to be displayed on the display <NUM>. A button <NUM> is for instructing to end displaying the inspection results. When the button <NUM> is selected, the screen displayed on the display <NUM> returns to the display screen shown in <FIG>.

<FIG> illustrates an example of a display screen which is displayed on the display <NUM> when the inspection apparatus <NUM> is being performing an inspection. The display screen shown in <FIG> is displayed when the button <NUM> shown in <FIG> is selected. An image of a sheet read by the inspection apparatus <NUM> is displayed in an image display area <NUM>. In a result display area <NUM>, an inspection result obtained by comparing the read image displayed in the image display area <NUM> with a correct answer image is displayed. In the example of the screen shown in <FIG>, the sheet read by the inspection apparatus <NUM> is determined to be normal, and thus "OK" is displayed in the result display area <NUM>. A button <NUM> is for instructing to end the inspection. When the button <NUM> is pressed, the inspection apparatus <NUM> end the inspection process, and the screen displayed on the display <NUM> return to the display screen shown in <FIG>. A button <NUM> is for instructing to display a confirmation screen for confirming instruction results of a whole job.

When the button <NUM> is selected, the display screen shown in <FIG> is displayed on the display <NUM>.

<FIG> illustrates an example of a display screen which is display when an image of a sheet read by the inspection apparatus <NUM> is determined to be abnormal. In the example shown in <FIG>, a streak <NUM> is detected on the image of the sheet read by the inspection apparatus <NUM>, and thus "NOT GOOD" is displayed in the result display area <NUM>.

Next, inspection modes executable by the image forming apparatus <NUM> are described below. The image forming apparatus <NUM> can execute two inspection modes, that is, an inline inspection (a first inspection mode) and an offline inspection (a second inspection mode). The inline inspection is a mode in which an inspection is performed while executing a print job by the printing apparatus <NUM> such that an image is formed on a sheet by executing the print job and the resultant sheet is conveyed to the inspection apparatus <NUM> for the inspection. The offline inspection is a mode in which the inspection is not performed on a sheet conveyed from the printing apparatus <NUM> to the inspection apparatus <NUM>, but the sheet is conveyed to the inspection apparatus <NUM> for the inspection independently of the execution of the print job. That is, in the offline inspection, the inspection is performed by the inspection apparatus <NUM> without executing the image forming process by the printing apparatus <NUM>. Note that the sheet inspected by the inspection apparatus <NUM> in the offline inspection is a sheet on which an image is formed by a printing apparatus other than the printing apparatus <NUM>. Also note that the offline inspection may be performed such that after a sheet on which an image is formed by the printing apparatus <NUM> is discharged to the large-capacity stacker <NUM>, the sheet is set by a user onto the inserter <NUM>, and the inspection of the sheet is performed by the inspection apparatus <NUM>.

In the inline inspection, the image forming apparatus <NUM> feeds a sheet from the sheet feed deck <NUM> or <NUM>, and the printing apparatus <NUM> forms an image on the sheet. The image forming apparatus <NUM> conveys the sheet to the inspection apparatus <NUM> via the sheet conveyance path <NUM>, and the inspection apparatus <NUM> reads an image of the sheet. Thus, the image forming apparatus <NUM> can sequentially inspect sheets on which images have been formed by the printing apparatus <NUM>.

On the other hand, in the offline inspection, the image forming apparatus <NUM> feeds sheets from the inserter tray <NUM> of the inserter <NUM>. The image forming apparatus <NUM> conveys the sheet to the inspection apparatus <NUM> via the sheet conveyance path <NUM>, and the inspection apparatus <NUM> reads an image of the sheet. This makes it possible for the image forming apparatus <NUM> to also inspect sheets printed by a printing apparatus other than the printing apparatus <NUM>.

Next, a method for setting the inspection mode of the image forming apparatus <NUM> is described with reference to <FIG>. <FIG> illustrates an example of an inspection mode selection screen displayed on the display <NUM>. The display screen shown in <FIG> is displayed on the display <NUM> when a user performs a predetermined operation on the operation unit <NUM>. The user selects an inspection mode to be executed by the image forming apparatus <NUM> on the inspection mode selection screen. A button <NUM> is for selecting the inline inspection mode, and a button <NUM> is for selecting the offline inspection.

The inline inspection may be set on the print job setting screen. The offline inspection may be set on a screen for setting the job type such as a print job, a scan job, or the like.

<FIG> illustrates an example of a setting screen for setting the operation of the image forming apparatus <NUM> when an abnormal sheet is detected in the inline inspection. The display screen shown in <FIG> is displayed on the display <NUM> when the button <NUM> shown in <FIG> is selected. The image forming apparatus <NUM> is capable of executing a recovery process or mode in the inline inspection mode. The image forming apparatus <NUM> may also be capable of executing a plurality of processes or modes in the inline inspection mode including the recovery process and one or more of a purge process/mode, a shift process/mode and a log only process/mode. For example, the image forming apparatus <NUM> is capable of executing the purge and recovery mode, the purge mode, the shift mode, and the log only mode in the inline inspection. Operations of the image forming apparatus <NUM> in these respective modes will be described later. A button <NUM> is for selecting the purge and recovery mode. A button <NUM> is for selecting the purge mode. A button <NUM> is for selecting the shift mode. A button <NUM> is for selecting the log only mode. A button <NUM> is for returning the screen to the inspection mode selection screen. A button <NUM> is for determining the operation of the image forming apparatus <NUM> in the inline inspection. The user can determine the operation of the image forming apparatus <NUM> in the inline inspection by selecting one of the buttons <NUM> to <NUM> and then selecting the button <NUM>.

<FIG> is illustrates an example of a setting screen for setting the operation of the image forming apparatus <NUM> when an abnormal sheet is detected in the offline inspection. The display screen shown in <FIG> is displayed on the display <NUM> when the button <NUM> shown in <FIG> is selected. The image forming apparatus <NUM> may be capable of executing one or more of a plurality of processes or modes in the offline inspection mode including one or more of a purge process/mode, a shift process/mode and a log only process/mode. For example, the image forming apparatus <NUM> is capable of executing the purge mode, the shift mode, and the log only mode in the offline inspection. Note that the image forming apparatus <NUM> is not allowed to set (execute) the recovery process/mode in the offline inspection. For example, the image forming apparatus <NUM> is not allowed to set (execute) the purge and recovery mode, in the offline inspection. A button <NUM> is for selecting the purge mode. A button <NUM> is for selecting the shift mode. A button <NUM> is for selecting the log only mode. A button <NUM> is for returning the screen to the inspection mode selection screen. A button <NUM> is for determining the operation of the image forming apparatus <NUM> in the offline inspection. The user can determine the operation of the image forming apparatus <NUM> in the offline inspection by selecting one of the buttons <NUM> to <NUM> and then selecting the button <NUM>.

In the present embodiment, the setting of the inspection mode of the image forming apparatus <NUM> is performed via the operation unit <NUM> and the display <NUM> of the printing apparatus <NUM>, but the setting may be performed by using the external controller <NUM> or the PC <NUM>.

Next, an operation of the image forming apparatus <NUM> is described for a case where the inspection apparatus <NUM> detects an abnormal sheet. In the following description, the operation is explained by way of example for a case of a job in which one copy includes five pages.

First, the operation of the image forming apparatus <NUM> is described below referring to <FIG> for a case where the operation is performed in the purge and recovery mode. <FIG> are diagrams for describing sheet discharge destinations in the purge and recovery mode. In the purge and recovery mode, in a case where the inspection apparatus <NUM> determines that a sheet is abnormal, the abnormal sheet is discharged to a discharge unit different from that for normal sheets, and an image corresponding to the image printed on the abnormal sheet is printed on another sheet according to image data used to form the image on the abnormal sheet. Note that the purge and recovery mode is allowed to be set only in the inline inspection. In the example shown in <FIG>, first to third sheets are normal and thus these sheets are discharged to the stack tray <NUM> in the purge and recovery mode. However, a fourth sheet is abnormal, and thus this sheet is discharged to the escape tray <NUM>. A fifth sheet following the abnormal sheet is not inspected by the inspection apparatus <NUM> and is discharged to the escape tray <NUM> as with the abnormal sheet. After the abnormal sheet and the sheet following the abnormal sheet are discharged to the escape tray <NUM>, the image forming apparatus <NUM> reprints a correct image corresponding to the image formed on the abnormal fourth sheet on a sixth sheet. Furthermore, an image corresponding to the image formed on the fifth sheet following the abnormal sheet is reprinted on a seventh sheet. The inspection apparatus <NUM> inspects the reprinted sixth and seventh sheets. When the reprinted sheets are normal, the sheets are discharged to stack tray <NUM>. Finally, as shown in <FIG>, a product in normal pages <NUM> to <NUM> are discharged in a correct order on the stack tray <NUM> and thus a normal product is obtained. On the other hand, the abnormal sheet and the sheet following the abnormal sheet are stacked on the escape tray <NUM>.

As described above, in a case where an abnormal sheet is detected, an image is reprinted on another sheet based on image data used in the forming the image of the abnormal sheet. This process is referred to as a recovery process. The process of discharging abnormal sheets to a discharge unit different from that for normal sheets is referred to as a purge process. That is, the purge and recovery mode is a mode in which the image forming apparatus <NUM> executes a predetermined process which is a combination of the purge process and the recovery process. In the purge and recovery mode, the image forming apparatus <NUM> does not perform inspection using the inspection apparatus <NUM> on a sheet following an abnormal sheet, and the following sheet is discharged to the escape tray <NUM>. Thus, a product obtained after the recovery process has a correct page order.

Next, the operation of the image forming apparatus <NUM> is described below referring to <FIG> for a case where the operation is performed in the purge mode. <FIG> are diagrams for describing sheet discharge destinations in the purge mode. In the purge mode, in a case where the inspection apparatus <NUM> determines that a sheet is abnormal, this abnormal sheet is discharged to a discharge unit different from that for normal sheets. In purge mode, the image forming apparatus <NUM> does not perform the recovery process. The purge mode can be set in both the inline inspection and the offline inspection. In the example shown in <FIG>, first to third sheets are normal and thus these sheets are discharged to the stack tray <NUM> in the purge mode. However, a fourth sheet is abnormal, and thus this sheet is discharged to the escape tray <NUM>. A fifth sheet is inspected by the inspection apparatus <NUM>. In this example, the fifth sheet is normal, and this fifth sheet is discharged to the stack tray <NUM>. Finally, the first to third sheets and the fifth sheet are stacked on the stack tray <NUM>, and only the sheet of the fourth page, which is abnormal, is stacked on the escape tray <NUM>. In the purge mode, the image forming apparatus <NUM> executes the purge process in the above-described manner.

Next, the operation of the image forming apparatus <NUM> is described below referring to <FIG> for a case where the operation is performed in the shift mode. <FIG> are diagrams for describing sheet discharge destinations in the shift mode. In the shift mode, in a case where the inspection apparatus <NUM> determines that a sheet is abnormal, this abnormal sheet is discharged to a position shifted by a predetermined amount from positions of normal sheets. In the shift mode, the image forming apparatus <NUM> does not perform the recovery process. The shift mode can be set in both the inline inspection and the offline inspection. In the shift mode, as shown in <FIG>, first to fifth sheets are discharged to the stack tray <NUM> regardless of whether the sheets are normal or not. In this process, an abnormal sheet (a fourth sheet in this specific example) is discharged to a position shifted by a predetermined amount, for example, in a direction perpendicular to the conveying direction with respect to the positions of normal sheets (the first to third sheets, in this example). Finally, the sheets of pages <NUM> to <NUM> are stacked on the stack tray <NUM> such that only the fourth sheet, which is abnormal, is shifted. The process of discharging the abnormal sheet to a position shifted by a predetermined amount from the positions of the normal sheets in the above-described manner is referred to as a shift process.

Next, the operation of the image forming apparatus <NUM> is described below referring to <FIG> for a case where the operation is performed in the log only mode. <FIG> are diagrams for describing sheet discharge destinations in the log only mode. In the log only mode, in a case where the inspection apparatus <NUM> determines that a sheet is abnormal, the abnormal sheet is discharged in the same manner as the normal sheets, and only logging of the abnormal sheet is performed (e.g. information identifying which of the sheets is an abnormal sheet is logged or recorded). In the log only mode, the image forming apparatus <NUM> does not perform the recovery process. The log only mode can be set in both the inline inspection and the offline inspection. In the log only mode, as shown in <FIG>, first to fifth sheets are discharged to the stack tray <NUM> regardless of whether the sheets are normal or not. Finally, the sheets of pages <NUM> to <NUM> including a fourth sheet, which is an abnormal sheet, are stacked on the stack tray <NUM> such that all pages are correctly aligned. That is, in the log only mode, as described above, all sheets are discharged in the same manner without discharging abnormal sheets in a different manner from the manner for normal sheets, and for the abnormal sheets, only logging is performed. The process performed in such that manner is referred to as a log only process.

Note that in all above-described modes, including the purge and recovery mode, the purge mode, the shift mode, and the log only mode, the inspection apparatus <NUM> records information about abnormal sheets, and the user can check the inspection results on the display <NUM>. In the examples shown in <FIG> to <FIG>, the fourth sheet is abnormal, and the CPU <NUM> of the inspection apparatus <NUM> records in the memory <NUM> information indicating that the fourth sheet is abnormal.

Of the purge and recovery mode, the purge mode, the shift mode, and the log only mode, the recovery process is executed only in the purge and recovery mode. Control flow.

Next, a control flow of the image forming apparatus <NUM> is described with reference to <FIG> and <FIG>. One or more steps of the control flow may be performed by a controller of the image forming system or apparatus <NUM> which may include CPU <NUM> and/or CPU <NUM> and/or CPU <NUM> and/or CPU <NUM> or may include a computer or processing unit that controls operations of at least the printing apparatus <NUM>, the inserter <NUM>, the inspection apparatus <NUM> (and may be also discharge portions of the stacker <NUM>).

<FIG> is a flowchart showing a flow of processing executed by the CPU <NUM> of the printing apparatus <NUM>. When a job is started, the CPU <NUM> determines whether or not the job includes an execution of an inspection (S1001). In this process (S1001), the CPU <NUM> makes the determination based on job information received from the external controller <NUM>.

In a case where it is specified to execute an inspection in a given job (Yes in S1001), the CPU <NUM> sends inspection setting information to the inspection apparatus <NUM>. For example, the inspection setting information may set by user (such as via the inspection setting screen shown in <FIG>). The inspection apparatus <NUM> inspects sheets according to this inspection setting information (S1002). The process executed by the inspection apparatus <NUM> will be described later. Next, the CPU <NUM> determines whether or not the offline inspection is specified as the inspection mode (S1003). In a case where the offline inspection is specified as the inspection mode (Yes in S1003), the CPU <NUM> instructs the inserter <NUM> to execute to feed sheets (S1004). As a result, the inserter <NUM> starts feeding sheets to the inspection apparatus <NUM>.

On the other hand, in a case where the job specifies not to perform the inspection (No in S1001) or in a case where the inline inspection is specified as the inspection mode (No in S1003), the CPU <NUM> executes a printing process (S1005). The CPU <NUM> then determines whether or not to execute the recovery process based on the result of the inspection performed by the inspection apparatus <NUM> (S1006). In a case where the recovery process is necessary (Yes in S1006), for example in the case where the inspection apparatus <NUM> determines that the sheet conveyed is an abnormal sheet, the CPU <NUM> executes the recovery process (S1007) and then ends the processing flow.

In a case where the recovery process is not necessary (No in S1006), for example in the case where the inspection apparatus <NUM> determines that the sheet conveyed is a normal sheet, the CPU <NUM> ends the processing flow without executing the recovery process.

The processing executed by the CPU <NUM> of the inspection apparatus <NUM> is described. <FIG> is a flowchart showing a flow of processing executed by the CPU <NUM> of the inspection apparatus <NUM>. The processing shown in this flowchart shown in <FIG> is started when a sheet is conveyed to the inspection apparatus <NUM>.

When the sheet is conveyed to the inspection apparatus <NUM>, the inspection apparatus <NUM> reads the images of the sheet using the reading units <NUM> and <NUM>, and inspects whether the images of the sheet are normal (S2001). In the case of the inline inspection, the inspection apparatus <NUM> inspects sheets on which images are formed by the printing apparatus <NUM>, while in the case of the offline inspection, the inspection apparatus <NUM> inspects sheets fed from the inserter tray <NUM> of the inserter <NUM>.

Next, the CPU <NUM> determines whether or not the inspected sheet is abnormal (S2002). In a case where the inspected sheet is abnormal (Yes in S2002), the CPU <NUM> records information related to the abnormal sheet (S2003).

Thereafter, the CPU <NUM> determines whether or not the purge and recovery mode is specified based on the inspection setting information sent from the CPU <NUM> (S2004). In a case where the purge and recovery mode is specified (Yes in S2004), the CPU <NUM> instructs the large-capacity stacker <NUM> to perform the purge process (S2005). Thereafter, the CPU <NUM> instructs the printing apparatus <NUM> to execute the recovery process such that a correct image corresponding to the image formed on the abnormal sheet is printed on another sheet (S2006). After that, the CPU <NUM> determines whether or not there is a next sheet (S2007). In a case where there is a next sheet (Yes in S2007), the processing flow returns to S2001. However, in a case where there is no next sheet (No in S2007), the CPU <NUM> ends the processing flow.

In a case where the purge and recovery mode is not specified (No in S2004), the CPU <NUM> determines whether the purge mode is specified (S2008). In a case where the purge mode is specified (Yes in S2008), the CPU <NUM> instructs the large-capacity stacker <NUM> to perform the purge process (S2009). Thereafter, the processing flow proceeds to S2007.

In a case where the purge mode is not specified (No in S2008), the CPU <NUM> determines whether the shift mode is specified (S2010). In a case where the shift mode is specified (Yes in S2010), the CPU <NUM> instructs the large-capacity stacker <NUM> to perform the shift process (S2011). Thereafter, the processing flow proceeds to S2007.

In a case where the shift mode is not specified (No in S2010), or in a case where a sheet inspected by the inspection apparatus <NUM> is normal (No in S2002), the CPU <NUM> instructs the large-capacity stacker <NUM> to discharge the sheet to the stack tray <NUM> (S2012) in a usual manner. Thereafter, the processing flow proceeds to S2007.

By performing the control in the above-described manner, the image forming apparatus <NUM> can perform the inline inspection and the offline inspection.

In the present embodiment, when the user selects the inline inspection, the user further selects one of the purge and recovery mode, the purge mode, the shift mode, and the log only mode (see <FIG>). On the other hand, when the user selects the offline mode, the user further selects one of the purge mode, the shift mode, and the log only mode (see <FIG>). That is, in the case where the user selects the offline inspection, the user is not allowed to further select the purge and recovery mode including the recovery process. Therefore, in the offline inspection, the CPU <NUM> always determines "No" in S2004 in the flowchart in <FIG>.

In the offline inspection, the image forming apparatus <NUM> does not perform image formation by the printing apparatus <NUM>, and thus the image forming apparatus <NUM> does not perform the recovery process. Therefore, in the present embodiment, as shown in <FIG>, when the offline inspection is selected, the options displayed on the display <NUM> do not include the purge and recovery mode. That is, when the offline inspection is selected, the CPU <NUM> prohibits the selection of the recovery process. This makes it possible to prevent the user from erroneously selecting the purge and recovery mode including the recovery process in the offline inspection. However, when the inline inspection is selected, the CPU <NUM> permits the selection of the recovery process.

In the present embodiment, when the offline inspection is selected, the image forming apparatus <NUM> does not display the purge and recovery mode as an option on the display <NUM> thereby prohibiting the selection of the recovery process. However, the method of prohibiting the recovery process is not limited to this example. For example, as shown in <FIG>, on the screen displayed on the display <NUM>, the option of the purge and recovery mode may be made unselectable by masking it (in the graying-out manner).

Next, a second embodiment is described. In the first embodiment described above, by way of example, the image forming apparatus <NUM> is configured to be capable of executing both the inline inspection and the offline inspection such that a user is prohibited from selecting the recovery process in the offline inspection mode. In contrast, in a second embodiment described below, when setting is made so as to execute the recovery process in the offline inspection, the image forming apparatus <NUM> notifies a user of an error and stops the job (e.g. stops the inspection job which involves inspecting sheets conveyed to the inspecting apparatus <NUM>). In the second embodiment, unlike the first embodiment, even when the offline inspection is selected, the user can select the purge and recovery mode. Note that the hardware configuration of the image forming system in the second embodiment is the same as that in the first embodiment, and thus a duplicated description thereof is omitted.

<FIG> is a flowchart showing a flow of control of an inspection job executed by the image forming apparatus <NUM> according to the second embodiment. When the job is started, the CPU <NUM> determines whether the inline inspection or the offline inspection is set as the inspection mode (S3001). In a case where the inline inspection is selected (Yes in S3001), the CPU <NUM> starts the print and inspection process (S3002). The print and the inspection process in S3002 is the same as the inline inspection process in the flowchart shown in <FIG> described above, and thus a further description thereof is omitted.

On the other hand, in a case where the offline inspection is selected (No in S3001), the CPU <NUM> determines whether or not the purge and recovery mode is selected (S3003). In a case where the purge and recovery mode is not selected (No in S3003), the CPU <NUM> executes the inspection process.

In a case where the purge and recovery mode is selected (Yes in S3003), the CPU <NUM> cancels the job (S3004). That is, in the case where the purge and recovery mode is selected in the offline inspection, the image forming apparatus <NUM> does not feed sheets by the inserter <NUM>. The CPU <NUM> displays an error screen on the display <NUM> (S3005).

<FIG> illustrates an example of an error screen displayed on the display <NUM>. After that, the CPU <NUM> ends the process.

As described above, when the purge and recovery mode including the recovery process is specified in the offline inspection, the image forming apparatus <NUM> cancels the job and does not feed sheets. Therefore, in the second embodiment, even when the user erroneously sets the recovery process to be executed in the offline inspection, the image forming apparatus <NUM> can prompt the user to remake the appropriate settings.

In the first and second embodiments described above, the image forming apparatus <NUM> can execute a plurality of modes including the purge and recovery mode, the purge mode, the shift mode, and the log only mode. However, to reduce the number of user operations, modes executed by the image forming apparatus <NUM> may be fixed in each of the inline inspection and the offline inspection. For example, the image forming apparatus <NUM> may be set to execute the purge and recovery mode in the inline inspection, and to execute the shift mode in the offline inspection. The modes executable by the image forming apparatus <NUM> in each of the inline inspection and the offline inspection in the first and second embodiments are merely examples, and modes selectable in each inspection mode may be different from those described in the above examples.

In the embodiments described above, the purge and recovery mode has been described as an example of a mode including the recovery process. However, the image forming apparatus <NUM> may be capable of executing a mode including the recovery process other than the purge and recovery mode. For example, the image forming apparatus <NUM> may be capable of executing a mode in which when an abnormal sheet occurs, the recovery process is performed without performing the purge process. In this case, modes including the recovery process other than the purge and recovery mode are also prohibited from being selected in the offline inspection, as with the purge and recovery mode.

In the embodiments described above, the image forming apparatus <NUM> feeds sheets from the sheet feed decks <NUM> and <NUM> in the inline inspection, and feeds sheets from the inserter <NUM> in the offline inspection. However, the sheet feeding method is not limited to this. For example, the image forming apparatus <NUM> may feed sheets from the sheet feed decks <NUM> and <NUM> in the offline inspection. In this case, the image forming apparatus <NUM> conveys sheets to the inspection apparatus <NUM> without forming an image by the printing apparatus <NUM>.

According to the present disclosure, it is possible to improve processing performed when an abnormal sheet occurs in an image forming system capable of performing both the inline inspection and the offline inspection.

Claim 1:
An image forming system (<NUM>) comprising:
image forming means (<NUM>) arranged to form an image on a sheet;
inspection means (<NUM>) arranged to inspect an image on a sheet;
conveyance means (<NUM>) arranged to convey a sheet to the inspection means (<NUM>);
a controller (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to execute a first inspection mode in which an image is formed on a sheet by the image forming means (<NUM>) and the sheet having the image formed thereon is conveyed by the conveyance means (<NUM>) to the inspection means (<NUM>) and is inspected by the inspection means (<NUM>), and a second inspection mode in which, without executing image forming by the image forming means (<NUM>), a sheet having an image formed thereon is conveyed by the conveyance means (<NUM>) to the inspection means (<NUM>) and inspected by the inspection means (<NUM>); and characterized by
setting means (<NUM>) arranged to set a recovery process such that in a case where the inspection means (<NUM>) determines that the sheet conveyed by the conveyance means (<NUM>) is an abnormal sheet having abnormality in the image, an image corresponding to the image formed on the abnormal sheet is formed according to image data used to form the image on the abnormal sheet by the image forming means (<NUM>) on a sheet different from the abnormal sheet,
wherein the setting means (<NUM>) permits the setting of the recovery process in the first inspection mode and does not permit the setting of the recovery process in the second inspection mode.