AR-CF1 (serv.man4). Saddle stitch unit basic operation - Sharp Copying Equipment Service Manual (repair manual). Page 37

To fold a stack consisting of 10 or more A4-R or LT-R sheets, folding is executed twice for the

same sheet.

The paper folding rollers rotate in reverse for an equivalent of 20 mm after gripping the stack for

a length of 20 mm, enabling the paper folding rollers to apply an increased degree of pressure along
the crease on the stack. Then, the paper folding rollers rotate normally, and the paper pushing plate
returns to its home position while the stack is being delivered.

This way, a stack requiring a large force may properly be folded with less pressure.

1) The paper pushing plate pushes the stack in the direction of the paper folding rollers.

M2S

Paper folding motor

M8S

Paper pushing plate motor

Paper pushing plate

Paper folding roller

2) The paper folding rollers grip the stack for a length of about 20 mm.

M2S

Paper folding motor

20 mm 

(approx.)