An image forming system that is capable of forming an image onto a sheet on a basis of print image data including multiple image data items imposed in such a manner as to be suitable for middle-folding and saddle-stitching and outputting a booklet by performing middle-folding and saddle-stitching includes: a storing unit that stores beforehand, as an output-processing content table, an inclination direction of a compilation tray onto which a stack of sheets that is to be subjected to imposition processing for pages or a facing page of the booklet and the middle-folding and saddle-stitching is placed; and a processing unit that generates the print image data by acquiring information of the inclination direction of the compilation tray, referencing to the output-processing content table, and performing the imposition processing.

A printing apparatus capable of conveying sheets to a sheet processing apparatus and to control the type of a sheet to be used as a cover sheet in a case where a book bound product is generated by switching back sheets each having an image printed, inverting the sheets and folding the inverted sheets, and to notify an error to a user based on the type of a sheet to be used as the cover sheet in a case where printing an image on the cover sheet is designated.

An image forming apparatus includes an image forming unit including an image bearing member, and a transfer unit, a fixing unit, a re-conveyance unit, a detection unit, and a control unit configured to execute a booklet mode while creating a booklet, the booklet including a first sheet having a first surface and a second surface opposite to the first surface, and a second sheet having a third surface arranged adjacent to the second surface of the first sheet. The control unit is configured to control the image forming unit such that, in the booklet mode, a toner image is transferred to the second surface before a toner image is transferred to the first surface of the first sheet, and a toner image to be formed on the third surface of the second sheet is corrected based on an information of the second surface detected by the detection unit.

A printing apparatus includes a printing unit that prints images on sheets, a sheet processing unit that executes bookbinding processing on sheets on which images have been printed by the printing unit, a stack control unit that stacks, in a stacking unit, bookbinding products on which bookbinding processing has been executed by the sheet processing unit, a setting unit that sets whether or not to activate a stacking limit of bookbinding products to be stacked on the stacking unit by the stack limiting unit, and a control unit that performs control so as to stop stacking in the stacking unit by the stack control unit in accordance with the stacking limit in the case where the stacking limit of bookbinding products has been set to activated by the setting unit.

A post-processing apparatus includes a post-processing unit configured to receive sheets from an image forming apparatus, perform processing on the received sheets, and then discharge the processed sheets through a discharge port. A sensor is configured to detect a presence of an object at the discharge port. The sensor includes a first light emitter on a first side of the discharge port that is positioned to emit a light across a width of the discharge port, a reflector on a second side of the discharge port opposite the first side in a first direction, and a first light receiver positioned to receive light of the first light emitter from the reflector. A controller is configured to terminate the processing on the received sheets by the post-processing unit when the sensor detects the presence of the object at the discharge port.

A post-processing apparatus according to an embodiment includes a processing tray, a post-processing section, a sensor, and a control section. A sheet supplied from an image forming apparatus is led into the processing tray through a lead-in path. The post-processing section applies post-processing to the sheet sent from the processing tray. The sensor detects an object passing a detection space in the lead-in path. The control section controls operation of the post-processing section based on a time in which the sensor detects the object.

A sheet transfer apparatus for transferring a sheet is provided with a back receiver section that rotates a sheet to transfer, and a support section that supports the back face of the back receiver section swingably. By this means, the back receiver section is capable of rotating smoothly.

An image forming apparatus includes an image forming portion, a fixing portion configured to perform a fixing process in which the fixing portion fixes the image and the powder adhesive to the sheet, and a bonding portion configured to perform a bonding process in which the bonding portion bonds the plurality of sheets to each other with the powder adhesive by using the heating member to heat and press the plurality of sheets, wherein P1<P2 is satisfied, where P1 (MPa) is a peak value of pressure received by the sheet in the fixing process, and P2 (MPa) is a peak value of pressure received by the sheet in the bonding process.

An image forming apparatus includes a processing tray, a post-processing controller, and a detection sensor. The processing tray is configured to support a sheet or a sheet bundle on which a post-processing is to be executed. The post-processing controller is configured to execute the post-processing on the sheet positioned on the processing tray. The detection sensor is configured to detect an object in a predetermined detection range including a space above the processing tray. The post-processing controller stops execution of the post-processing when the detection sensor detects the object at a determination timing other than a timing at which passage of the sheet or the sheet bundle through the detection range is estimated.

A post-processing apparatus according to an embodiment includes a processing tray, a post-processing section, a sensor, and a control section. A sheet supplied from an image forming apparatus is led into the processing tray through a lead-in path. The post-processing section applies post-processing to the sheet sent from the processing tray. The sensor detects an object passing a detection space in the lead-in path. The control section controls operation of the post-processing section based on a time in which the sensor detects the object.