Abstract: A lens having radially extending members provided with convex engaging projections is positioned and secured in a lens supporting sleeve having L-shaped openings with recessed engaging grooves. The radially extending members are positioned with respect to a reference surface of the sleeve, and subsequently elastically deform circumferentially extending clamping arms of the sleeve as they are rotated into clamping portions of the L-shaped openings. The convex engaging projections are then snapped into the engaging grooves, holding the lens in position.

Abstract: A finisher capable of binding a stack of sheets at a plurality of desired positions by a single stapler. When a plurality of stacks of sheets should be each stapled at two positions, the stapler is controlled such that the last stapling position of the preceding stack is the position where the following stack is stapled first.

Abstract: A finisher for use with a copier, printer or similar image forming apparatus for stapling or otherwise finishing paper sheets sequentially driven out of the apparatus. A paper sheet is introduced in a stapling section of a stapling device by being switched back, while being accurately guided by a guide member having a sufficient length. The stapling device is movable, independently of jogger fences which position paper sheets, to a particular position which is optimal for the size of stacked paper sheets and the position in which they are used. When a staple error detector detects a stapling error, a discharge path in use is switched over to another path. When a stapled paper stack is discharged, it is deformed in a wave-like configuration in a direction perpendicular to an intended direction of transport to be provided with a certain degree of rigidity. This allows the stapled paper stack to be driven out stably, epecially without being loosened at the discharge side.