Patent ID: 7926799

Claim:
A sheet post-processing apparatus comprising; A stapler configured to stitch with staples a sheet bundle conveyed along a conveyance path, the stapler stitches the sheet bundle at plural places thereof along a straight line orthogonal to the conveyance direction; a folding device including a pair of folding rollers disposed downstream of the stapler on the conveyance path and a blade that pushes the sheet bundle into a contact portion of the pair of folding rollers; a folding roller drive motor that drives the pair of folding rollers; and a controller configured to control the driving or stopping operation of the folding roller drive motor in correspondence to the process of folding the sheet bundle, the controller uses a voltage-type inverter comprising plural switching elements to generate a pulse width modulation control signal, and varies the speed of the folding roller drive motor during a period before the blade comes in contact with the sheet bundle, a speed of the folding roller drive motor during a period when the sheet bundle after folding work is being transported to a discharge port, a speed of the folding roller drive motor during a period when the sheet bundle is being discharged, and a speed of the folding roller drive motor during a period when the folding roller drive motor is being returned to a home position, the pulse width modulation control signal corresponding to a torque command is ON to switch ON the switching elements to apply a drive current in a direction, and the pulse width modification of the controller applies the drive current in an opposite direction when the pulse width modulation control signal is OFF to switch OFF the switching elements.