The present invention is to provide a sheet aligning apparatus that is capable of detecting misalignment. A control portion of a post-processing apparatus causes a front aligning member and a rear aligning member to be moved to an aligning position to align sheets conveyed to a processing tray, and determines whether an electrostatic capacitance sensor detects misalignment (sheet shifting from a sheet bundle). After the control portion determines that there is no misalignment, the control portion performs detection strength adjusting for a sensor and initial value setting for detecting misalignment of a next sheet.

The present invention is to provide a sheet aligning apparatus that is capable of detecting misalignment. A control portion of a post-processing apparatus causes a front aligning member and a rear aligning member to be moved to an aligning position to align sheets conveyed to a processing tray, and determines whether an electrostatic capacitance sensor detects misalignment (sheet shifting from a sheet bundle). After the control portion determines that there is no misalignment, the control portion performs detection strength adjusting for a sensor and initial value setting for detecting misalignment of a next sheet.

The present invention is to provide a sheet aligning apparatus that is capable of detecting misalignment. A control portion of a post-processing apparatus causes a front aligning member and a rear aligning member to be moved to an aligning position to align sheets conveyed to a processing tray, causes the front aligning member to be moved from the aligning position to a detecting position, and determines whether an electrostatic capacitance sensor detects misalignment (sheet shifting from a sheet bundle). When it is determined that the senor detects misalignment, the front aligning member is moved from the detecting position to the aligning position so that sheets are realigned.

A sheet processing device includes a housing, a sheet stacking portion, a sheet discharge portion, a contact member, a conveyance unit, and an association mechanism. A sheet discharge portion is disposed in the housing and faces a space over the sheet stacking portion, the sheet discharge portion including a pair of discharge rollers. The contact member is disposed in the sheet discharge portion, and is movable to project into a sheet conveyance passage to come into contact with a surface of the sheet. The conveyance unit is selectively mounted in the space of the housing, and is configured to receive a sheet delivered by the pair of discharge rollers and convey the sheet. The association mechanism is operable to cause the contact member to recede from the sheet conveyance passage in association with the mounting of the conveyance unit in the housing.

A sheet detection device includes a measurement unit for measuring a feature amount of a sheet conveyed by a conveyance unit, a pressing member movable between a first position separated from the measurement unit and a second position closer to the measurement unit than the first position, and a moving unit configured to move the pressing member, wherein the pressing member is arranged by the moving unit at the first position in a case where the sheet has not been conveyed by the conveyance unit to a measurement position of the measurement unit, wherein the moving unit is configured to move the pressing member to the second position from the first position in a case where the sheet has been conveyed by the conveyance unit to the measurement position of the measurement unit.