A post-processing apparatus for an image forming apparatus includes a processing tray on which a sheet bundle is placed for discharging onto a discharge tray, a detector configured to detect presence or absence of the sheet bundle on the processing tray, and a controller. The controller is configured to control driving of the processing tray to discharge the sheet bundle onto the discharge tray and to determine whether or not to output an error if a detection result of the detector after the processing tray has been driven to discharge the sheet bundle onto the discharge tray indicates presence of the sheet bundle. The controller outputs the error if the sheet bundle is not a last sheet bundle of a post-processing job and does not output the error if the sheet bundle is the last sheet bundle of the post-processing job.

A post-processing apparatus for an image forming apparatus includes a processing tray on which a sheet bundle is placed for discharging onto a discharge tray, a detector configured to detect presence or absence of the sheet bundle on the processing tray, and a controller. The controller is configured to control driving of the processing tray to discharge the sheet bundle onto the discharge tray and to determine whether or not to output an error if a detection result of the detector after the processing tray has been driven to discharge the sheet bundle onto the discharge tray indicates presence of the sheet bundle. The controller outputs the error if the sheet bundle is not a last sheet bundle of a post-processing job and does not output the error if the sheet bundle is the last sheet bundle of the post-processing job.

A length, in a lengthwise direction, of a sheet to be inspected by an inspection unit may be longer than a length of a conveyance path between a branch position corresponding to an initial branch path in a plurality of branch paths and a reading position of a reading apparatus. The sheet inspected by the inspection unit is not discharged to a stacking unit corresponding to the initial branch path, and is discharged to a stacking unit corresponding to a branch path branching from a main path at a branch position located further downstream than a branch position corresponding to the initial branch path.

A length, in a lengthwise direction, of a sheet to be inspected by an inspection unit may be longer than a length of a conveyance path between a branch position corresponding to an initial branch path in a plurality of branch paths and a reading position of a reading apparatus. The sheet inspected by the inspection unit is not discharged to a stacking unit corresponding to the initial branch path, and is discharged to a stacking unit corresponding to a branch path branching from a main path at a branch position located further downstream than a branch position corresponding to the initial branch path.

A sheet sorting apparatus includes a second tray arranged below a first tray detachable from a main body having a first discharge port corresponding to the first tray and a second discharge port corresponding to the second tray, a discharge unit, a tray detecting unit, and a control unit. The discharge unit discharges a sheet toward the first or second discharge port. In a state that the first tray is detached from the main body and the discharge unit discharges sheets from the first discharge port to the second tray and then the first tray is detected as attached to the main body, the control unit selects a discharge destination of a second sheet, subsequent to a first sheet discharged and stacked first after the first tray is attached to the main body, such that the second sheet is stacked on a tray having the first sheet thereon.

A sheet conveying device, which is included in a sheet discharging device and an image forming apparatus, includes a contact body configured to rotate while contacting a sheet in conveyance, a shaft configured to rotate together with the contact body in a range of rotation of the contact body, a sheet detector configured to detect the sheet through detection of rotation of the shaft, and a rotary body support configured to rotatably support the contact body to the shaft, extending the range of rotation, in a same direction as the direction of rotation of the shaft. The sheet discharging device includes a sheet discharging body, a sheet stacker of the sheet discharged, and the above-described sheet conveying device. The sheet detector is a stack height detector configured to detec't that the height of the sheet stacked on the sheet stacker is equal to or higher than a predetermined height.

An image forming apparatus includes: a first apparatus configured to perform punching on a sheet by using a punching member; a second apparatus, including a stacking part on which a plurality of sheets punched by the first apparatus is stacked, and configured to perform binding so as to obtain a bookbinding article in which a binding member penetrates in a ring shape through punched holes of the plurality of sheets; a notification unit notifying information; and a control unit configured, in a case of starting a job using the first apparatus and the second apparatus and determining that a jam has occurred in the stacking part, to cancel the job, and to cause the notification unit to notify that a thickness of a sheet stack stacked on the stacking part exceeds a thickness that enables to be bound by the binding member used by the second apparatus.

An image rendering apparatus and method of operating a center tray of an image rendering apparatus. The image rendering apparatus includes a cavity, and a center tray having a home position located within the cavity and a retrieval position located outside the cavity. The image rendering apparatus further includes a retraction mechanism that is attached to the center tray and an interior wall of the cavity. The retraction mechanism is configured to allow for the extension of the center tray from the home position to the retrieval position, and from the retrieval position to the home position.

The present invention is to provide a sheet stacking device for stacking sheets on which an image is formed, in which an initial operation time at the time the device is turned on is shortened, and, at the same time, the initial operation is simplified. This configuration enables reduction in operation noise and a prompt start at the time when the device is started.

The present invention is to provide a sheet stacking device for stacking sheets on which an image is formed, in which an initial operation time at the time the device is turned on is shortened, and, at the same time, the initial operation is simplified. This configuration enables reduction in operation noise and a prompt start at the time when the device is started.