According to one embodiment, a sheet post-processing apparatus includes: a standby unit configured to put a sheet on standby, the standby unit including a tray member on which the sheet is placed; a corrugation forming unit configured to form a corrugation in a direction orthogonal to a conveying direction on the sheet in the standby unit, the corrugation forming unit integrally provided with the tray member; and a processing unit disposed below the standby unit and configured to process the sheet supplied from the standby unit, wherein the corrugation forming unit includes: a projecting roller projecting upward from a conveyance reference plane in the standby unit; and a housing unit configured as a part of the tray member to house the projecting roller below the conveyance reference plane.

A printing device includes a first ejector that ejects a recording medium to an exterior, a second ejector that enhances a rigidity of the recording medium more than by the first ejector, and ejects the recording medium to the exterior, and an ejector selector that selects either the first ejector or the second ejector.

An image forming apparatus includes a control unit configured to execute a sheet discharge mode. If a case where a distance between the leading edge and the nip portion is a first distance is a first case, and a case where a distance between the leading edge of the sheet and the nip portion is a second distance shorter than the first distance and the temperature detected by the temperature detection unit is the same as that in the first case is a second case, the control unit is configured to set a conveyance speed of the sheet in discharging the sheet toward the nip portion in the second case to be slower than that in the first case, in the sheet discharge mode.

A post-processing device includes an output unit that outputs a medium; a stacking unit on which the medium that is output is stacked; and a blow-out unit that is disposed below the output unit and that blows gas toward the medium that is output, wherein an amount of the gas blown is adjusted in accordance with a type of the medium.

A discharging member includes an electrically conductive knit fabric, a support member, and a first magnet member. The conductive knit fabric is knitted into a cylindrical shape with use of yarn formed by twisting together a plurality of metal fibers. The support member is cylindrical shaped and inserted in the conductive knit fabric. The first magnet member is placed inside the support member. With the conductive knit fabric grounded or with a voltage applied to the conductive knit fabric, the discharging member is placed in noncontact with a discharged member in such a fashion that the first magnet member is opposed to the discharged member with the support member and the conductive knit fabric interposed therebetween.

A sorting device includes a base portion and a tray portion. The tray portion is supported on the base portion to be reciprocatable between a first shift position, where the tray portion is located at one side in the sheet width direction, and a second shift position, where the tray portion is located at the other side in the sheet width direction. The tray portion has a cutout portion. The cutout portion is formed by cutting away, with a predetermined width, an end part of the tray portion in the sheet width direction inward across the tray portion. With the tray portion at the second shift position, the cutout portion is located below one side end edge of the sheet in the sheet width direction, of sheets stacked on the tray 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.

An image forming device includes a device body; a conveyance table that is inserted into and pulled out of the device body and that forms a conveyance path for a sheet; a sheet mount tray; a paper feeder that feeds the sheet from the sheet mount tray to the conveyance path; and a movable support that movably supports the paper feeder on the conveyance table in a state where the conveyance table is pulled out of the device body. The paper feeder covers a predetermined part of the conveyance path in a state where the paper feeder disposed on the conveyance table is inserted into the device body, the sheet mount tray is disposed in the device body and separates from the paper feeder when the conveyance table is pulled out of the device body, and the paper feeder moves away from the predetermined part.

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 sealing member sealing a gap between one member and another member includes a mounting portion that is mounted on the one member and an extension portion that extends from a mounting portion side to another member side and contacts with the other member. In the sealing member, the extension portion includes an assist portion that is formed in one end toward the other member side and assists spring-up of the extension portion in accordance with sliding of the other member or the one member.