Sheet stacking apparatus, sheet processing apparatus and image forming apparatus

摘要

The invention provides a sheet stacking apparatus including a stacking tray whose stacking surface is inclined, a sheet presence/absence detecting sensor that detects presence and absence of a sheet on the stacking surface, an abutting member to which an end of the sheet on the stacking surface abuts, an alignment mechanism that aligns the sheet on the stacking surface widthwise by a pair of aligning members, and a control portion that controls the aligning mechanism. Determining presence of the sheet on the stacking tray from a detected result of the sheet presence/absence detecting sensor, the control portion aligns the sheet by setting a distance between aligning faces of the pair of aligning members as a first distance, and determining absence of the sheet, the control portion sets the distance between the aligning faces of the pair of aligning members as a second distance which is wider than the first distance.

主权项

1. A sheet stacking apparatus comprising:
a sheet discharging portion configured to discharge a plurality of sheets; a stacking portion having a stacking surface on which each sheet discharged from the sheet discharging portion is stacked; a sheet presence/absence detecting portion that detects whether a sheet is present or absent on the stacking surface of the stacking portion; an abutting portion against which each end in a sheet discharge direction of the sheets discharged by the sheet discharging portion and stacked on the stacking surface abuts; an alignment mechanism including a pair of aligning members respectively having aligning faces that align the sheets discharged onto the stacking surface in a sheet width direction; and a control portion that controls the aligning mechanism based on a detected result of the sheet presence/absence detecting portion indicating a presence of the sheet on the stacking surface of the stacking portion such that a distance between the aligning faces of the pair of aligning members is set as a first distance, and controls the aligning mechanism based on a detected result of the sheet presence/absence detecting portion indicating an absence of the sheet on the stacking surface of the stacking portion such that the distance between the aligning faces of the pair of aligning members is set as a second distance, the second distance being wider than the first distance and being wider than a widthwise length of the sheet discharged onto the stacking surface.