An image forming system includes: an image former that forms an image; a stacker that stacks a recording medium on which an image has been formed by the image former and which has been discharged from the image former; a lifter that raises or lowers the stacker between a stacking position where the recording medium is stacked and a lower position located below the stacking position; a recording medium detector that detects the recording medium stacked on the stacker; and a hardware processor that controls driving of the lifter so as to lower the stacker from the stacking position to the lower position when it is determined that the recording medium is on the stacker on the basis of a detection result of the recording medium detector within start-up time from a time when power is switched on to a time of shifting to an image formable state.

An image forming apparatus includes an upper guide unit fixed to the image forming apparatus and configured to guide an upper surface of the sheet discharged by a roller pair, a stack unit provided at a position recessed from an upper exterior unit of the image forming apparatus, and an operation unit including a display unit. The discharged sheets are stacked on the stack unit. The upper guide unit extends more to a downstream side in the discharge direction than the roller pair. The operation unit and the upper guide unit each have a portion overlapping with each other. When viewed in an axial direction of the roller pair, the operation unit and the upper guide unit are arranged at positions through which a straight line orthogonal to a plane passing through axes of rollers of the roller pair and passing through a nip portion of the roller pair passes.

An image forming apparatus includes a unit group including a specific unit having a specific component that performs an operation necessary for notification of paper remaining on a mounting surface; and a processor configured to control supply of power to the unit group at a return from a sleep state based on a return event, in which the processor is configured to in a case where there is no paper on the mounting surface at a transition to the sleep state, perform first control to supply power to a specified power supply destination corresponding to the return event at the return from the sleep state, and in a case where there is a paper on the mounting surface at the transition to the sleep state, perform second control to supply power to the specific unit at the return from the sleep state even in a case where the specific unit is not included in the specified power supply destination of the unit group.

A sheet discharging apparatus includes a discharging portion configured to discharge a sheet, a supporting portion configured to support the sheet discharged by the discharging portion, a lifting portion configured to lift and lower the supporting portion, a transmissive sensor configured to output an output signal that changes in accordance with a position of an upper surface of the sheet supported by the supporting portion, a reflective sensor configured to output an output signal that changes in accordance with the position of the upper surface of the sheet supported by the supporting portion, and a controller configured to control the lifting portion and including a first determining portion configured to determine whether or not sheet detection by the transmissive sensor is possible and a second determining portion configured to determine whether or not sheet detection by the transmissive sensor is needed.

A sheet processing apparatus capable of discharging even a lateral displacement uncorrectable sheet onto a discharge tray without collision with an alignment plate. A finisher conveys a sheet along a conveying path. A shift unit corrects a lateral displacement of the sheet based on a result of detection by a lateral displacement detection sensor. Sheets discharged via the conveying path are stacked on a discharge tray. A pair of alignment plates disposed above the stacking tray are lowered and are moved between a standby position and an alignment position to be brought into abutment with respective opposite edges of the discharged sheet in the alignment position. A finisher controller makes a distance between the alignment plates in a standby position different according to a sheet type, even when a size of the sheet in the width direction is the same.

A sheet loading device is provided with a sheet ejection portion, a sheet loading portion, a first detection mechanism, a driving device, a second detection mechanism, and a control portion. The driving device drives the sheet loading portion to ascend/descend between an upper surface detection position and a reference position made to descend by a prescribed distance from the upper surface detection position. The second detection mechanism detects that the sheet loading portion is at the reference position. In a case where sheets of the same type are ejected continuously from the sheet ejection portion, the control portion controls beforehand the sheet loading portion to ascend from the reference position to the upper surface detection position and sets a loadable number of sheets of the sheet loading portion in accordance with an ascending time of the sheet loading portion.

A sheet discharging apparatus includes a discharging portion configured to discharge a sheet, a supporting portion configured to support the sheet discharged by the discharging portion, a lifting portion configured to lift and lower the supporting portion, a transmissive sensor configured to output an output signal that changes in accordance with a position of an upper surface of the sheet supported by the supporting portion, a reflective sensor configured to output an output signal that changes in accordance with the position of the upper surface of the sheet supported by the supporting portion, and a controller configured to control the lifting portion and including a first determining portion configured to determine whether or not sheet detection by the transmissive sensor is possible and a second determining portion configured to determine whether or not sheet detection by the transmissive sensor is needed.

A stacked-sheet detection device includes a main shaft portion, a first detection arm portion, a parallel shaft portion, a second detection arm portion, an interlocking arm portion, a detected portion, and a detection sensor. The second detection arm portion is provided outside a first passing range, rotates in a predefined rotation direction and causes the interlocking arm portion to rotate in the predefined rotation direction by contacting a sheet that passes through a second passing range. When at least one of the first detection arm portion and the interlocking arm portion rotates in the predefined rotation direction, the main shaft portion rotates in the predefined rotation direction, and the detected portion rotates in the predefined rotation direction.

A sheet processing device is for binding sheets together. The sheet processing device includes binding units differing from each other in maximum sheet count, the maximum sheet count being a maximum number of sheets that can be bound at a time; a sheet tray configured to hold sheets until all to-be-bound sheets are placed therein, the number of the to-be-bound sheets being a largest one of the maximum sheet counts of the binding units or smaller; and a stacked-sheet-count limiting unit situated in a thickness direction of the sheets held in the sheet tray. The stacked-sheet-count limiting unit is configured to limit the number of sheets held in the sheet tray by varying a distance from a sheet support surface of the sheet tray on which the sheets are placed, depending on one of the binding units by which the sheets held in the sheet tray are to be bound.

A sheet sorting device includes a plurality of trays, a tray shifter, a tray stop position detector, and circuitry. The plurality of trays is disposed in multiple stages in a vertical direction and configured to stack a sheet. The tray shifter is configured to move the plurality of trays separately in a tray shift direction. The tray stop position detector is configured to detect stop positions of the plurality of trays separately. The circuitry is configured to cause the tray shifter to move the plurality of trays to home positions in an initial operation, at least one tray having a home position opposite to a home position of another tray in the tray shift direction. The circuitry is configured to, while moving the plurality of trays at a same time in the initial operation, cause the tray shifter to move the trays in directions opposite to each other.