Plate cylinder drive unit in printer

摘要

The present invention eliminates backlash between a drive helical gear and a driven helical gear and facilitates rotation of a driven gear member to increase rotational accuracy of a plate cylinder. A plate cylinder drive unit includes a plate cylinder drive shaft, a driven gear member having a driven helical gear that meshes with a drive helical gear and attached around the plate cylinder drive shaft, a position adjustment member moving the driven gear member to fix it at a predetermined position, a whirl-stop member attached to the plate cylinder drive shaft, a sandwiching member removably fixing the whirl-stop member to the driven gear member, a backlash eliminating helical gear disposed on one side of the driven helical gear, first springs bringing the backlash eliminating helical gear in pressure-contact with the driven helical gear, and second springs biasing the backlash eliminating helical gear to rotate it in a predetermined direction.

主权项

1. A plate cylinder drive unit in a printer which rotatably drives a plate cylinder by transmitting rotation of a drive helical gear to a plate cylinder comprising:
a plate cylinder drive shaft rotatably supported on a frame of the printer and connected to the plate cylinder to rotate integrally with the plate cylinder; a driven gear member having a driven helical gear that meshes with the drive helical gear and attached around the plate cylinder drive shaft in such a manner that the driven gear member is rotatable and axially movable with respect to the plate cylinder drive shaft; register means for axially moving the driven gear member with respect to the plate cylinder drive shaft and fixing the driven gear member at a predetermined position; a whirl-stop member attached to the plate cylinder drive shaft in such a manner that the whirl-stop member is nonrotatable but axially movable with respect to the plate cylinder drive shaft; whirl-stop-member fixation means for removably fixing the whirl-stop member to the driven gear member; a backlash eliminating helical gear disposed on one side of the driven helical gear in such a manner that the backlash eliminating helical gear is rotatable and axially movable within a predetermined range with respect to the driven helical gear; a first elastic member biasing the backlash eliminating helical gear toward the driven helical gear to bring the backlash eliminating helical gear in pressure contact with the one side of the driven helical gear; and a second elastic member biasing the backlash eliminating helical gear in such a manner that the backlash eliminating helical gear rotates in a predetermined direction with respect to the driven helical gear.