Sheet finishing apparatus and sheet finishing method

The sheet finishing apparatus comprising:

• a folding roller that nips the middle of bundle of sheets and forms a fold line;
• a fold reinforcing roller that reinforces the fold line of the bundle by moving along the fold line while applying a pressure to the fold line;
• a stack tray that stacks the bundles of which the fold is reinforced;
• a motor that drives the fold reinforcing roller;
• a rotating detection unit that detects a rotating number of the motor;
• and
• a control unit that moves the fold reinforcing rollers in a reverse direction when the rotating number, which is detected by the rotating detection unit, does not reach a predetermined rotating number after a certain time is passed, controls the motor to be on standby at a position where the discharge of the bundle is not interrupted, and discharges the bundles of paper to the stack tray forcibly.

A sheet finishing method comprising:

• forming a fold by nipping the middle of bundle of sheet with a folding roller;
• reinforcing the fold line of the bundle by moving a fold reinforcing roller along the fold line while applying a pressure to the fold line with the fold reinforcing roller;
• stacking the bundle of which the fold line is reinforced on a stack tray;
• and
• setting a number of times of fold reinforcing performed by the fold reinforcing roller to a first number when it is determined that a quantity of stacked bundle on the stack tray is less that a predetermined standard quantity which is set to be less than a maximum stack quantity, and setting a number of times of the fold reinforcing performed by the fold reinforcing roller to a second number greater than the first number when it is determined that the quantity of stacked bundle is greater than the predetermined standard quantity.