Multi-colour electrostatic copier with precise developer registration - has rotating developer housing whose orientation is controlled by two electric motors and click-stop registration mechanism

摘要

A multicolour electrostatic copier has a revolving cylindrical housing which accommodates separate quadrantal containers for each of the toner colours and is required to stop precisely w.r.t. the orientation of the image-bearing drum (1) during transfer of the toner. The housing is rotated by a main stepping motor in taking up a specific colour position and is arranged to overshoot the required stop position by a small angle. A second motor then reverses the housing rotation to enable a spring-loaded (67) roller (66) to locate in a shaped slot (65) on the housing periphery which defines the exact position required in the manner of a click-stop mechanism.