A postprocessing apparatus includes a horizontal alignment plate, a binder, a tray, and a shift actuator assembly. The horizontal alignment plate is positioned to align sheets in a sheet width direction. The binder binds sheets to form bound sheet bundles. The bound sheet bundles are stacked on the tray. The shift actuator assembly shifts the bound sheet bundles in the sheet width direction. A postprocessing controller controls the shift actuator assembly to shift the bound sheet bundles such that swollen portions of the bound sheet bundles are shifted inward of the horizontal alignment plate in the sheet width direction when the processed sheets are piled on the tray to the vicinity of the horizontal alignment plate.

A sheet stacking apparatus includes a pair of sheet alignment mechanisms disposed to face each other in a direction of conveyance of a sheet or in a direction orthogonal to the direction of conveyance. Each one of the pair of sheet alignment mechanisms includes an aligning member, an elastic member, a driver, and a driving source. The aligning member reciprocates with reference to the sheet. The elastic member extends due to reaction force generated in response to pressing force applied to an edge of the sheet by the aligning member when a size of the sheet is larger than a prescribed size. The driver is coupled to the aligning member via the elastic member. The driving source transfers a driving force to the driver.

An image reading apparatus includes a stacking portion, a feeding unit, a reading unit, and a discharge portion provided below the stacking portion. The feeding unit feeds a sheet stacked on the stacking portion in a feeding direction. The reading unit reads an image on the fed sheet and the discharge portion discharges the read sheet. The stacking portion includes first and second support surfaces that support the sheet and first and second regulating units to regulate a position of the sheet in a widthwise direction using two opposing ends of the sheet. The second support surface is retractable from a predetermined section above the discharge portion. The first support surface includes a downstream support portion that supports the sheet on a downstream side of the predetermined section in the feeding direction. A part of the second regulating surface is positioned on the downstream support portion.

A medium feeding apparatus includes a medium mounting section, a movable edge guide that guides both edges of the medium mounted on the medium mounting section and has a first edge guide and a second edge guide, a feeding section, and a width adjuster configured to adjust a guide width depending on the medium. The width adjuster includes a first adjuster having a first holding section and a first guiding section, and the second adjuster having a second holding section and a second guiding section. The first holding section holds a part of the first edge guide, the first guiding section guides the edge of the medium between the first edge guide and the second guiding section, the second holding section holds a part of the second edge guide, and the second guiding section guides the edge of the medium between the second edge guide and the first guiding section.

To provide a post-processor capable of executing alignment processing with high accuracy. Configuring a post-processor including: a recording material loader on which a recording material conveyed through a conveyance path is loaded; an aligner that aligns the recording material in the recording material loader; a driver that moves the aligner; and a controller that receives information of a physical property value of the recording material acquired by a medium sensor and determines an operation parameter of alignment processing that drives the driver based on the information of the physical property value.

A sheet conveying device includes a tray, a device body having a conveying route of a sheet and supporting the tray, a side guide supported by the tray to be movable in a first direction intersecting with a conveying direction of the sheet and contacting an end portion in the first direction of the sheet placed on the tray, a cover rotatable with respect to the device body and covering the conveying route, and a lock lever locking the cover to the device body and provided in a position overlapping the side guide in a second direction intersecting with the conveying direction and the first direction. The lock lever is rotatable between a lock position where the cover is locked and a release position where the cover is released. The side guide includes a first notched portion facing a rotation track of the lock lever with a gap.

A sheet feeding device includes a sheet feeding cassette, which is detachable with respect to a sheet feeding cassette mounting portion provided on an image forming device body. The sheet feeding cassette includes a storage portion that stores a paper sheet, a first regulator provided on a bottom portion of the storage portion that regulates the position of a paper sheet, and a movable placement plate that upwardly pushes a paper sheet stored in the storage portion. The movable placement plate includes a second regulator that regulates the position of a paper sheet having a different size to the size of a paper sheet that can be regulated by the first regulator.

A medium placement device includes a placement unit configured to have cut single paper thereon, a cover member configured to have single paper supplied to or discharged from an opening portion thereon, and a movement unit configured to move the cover member between a first position and a second position that is lower than the first position.

A recording material transport device including a transport section that transports a recording material and a support member disposed to extend in a direction intersecting with a vertical direction, and supporting the recording material from below with the transport stopped, in which the support member is provided to be capable of descending, and, as the support member descends, both of one end portion and the other end portion in the direction intersecting with the vertical direction descend and are inclined such that the one end portion is positioned below the other end portion.

A sheet cassette includes a sheet mounting unit, a first side guide, a second side guide, and a biasing unit. The first side guide comes into contact with the sheet at one end in a sheet width direction. The sheet width direction is a direction perpendicular to a sheet conveying direction in which the sheet is conveyed out from the sheet mounting unit. The sheet width direction is parallel to the mounting surface . The second side guide comes into contact with the sheet at the other end in the sheet width direction. The biasing unit has a biasing member. The biasing member biases at least the first side guide in a direction approaching the second side guide. The first side guide can rotate around a rotation shaft intersecting the mounting surface in a direction in which the first side guide approaches and separates from the second side guide.