Image forming apparatus and control system therefor

Abstract

A control system for a color copier which sets up an adequate color copying time for any particular size of paper sheets. A color document is repeatedly scanned to sequentially expose a single photoconductive drum, which is rotated at a constant speed, to a plurality of separated color components. Each of the latent images is developed by toner complementary in color to the color component associated with the latent image, and sequentially transferred to a paper sheet. The control system includes a paper size setting circuit, a scanning sensor for sensing the start of a scanning, and a home sensor for sensing an instantaneous angular position of the transfer drum. A control circuit is constructed to determine a transfer start and a transfer end time in response to a paper size signal, an output signal of the scanning sensor, and an output signal of the home sensor, and to variably control the rotation speed of the transfer drum during the interval between the transfer start and transfer end times so as to register the leading end of a paper sheet loaded on the transfer drum and that of each of the toner images.

Dependencies are inferred from the claim text.