Color printer using circulation period to control registration of images

摘要

A color printer of the type that prints color images by sequentially transferring from a photosensitive drum toner images of different colors in color registration to each other on a recording sheet being circulated by a conveyer belt, the color printer having an improved color registration capability. In order to avoid influences of variations in printer constants, such as elongation and contraction of the conveyer belt due to accumulated changes and temperature variations, etc., the position of the formation of a plurality of toner images of different colors on the recording medium is controlled with high precision by controlling the position or timing of formation of two successive toner images of different colors by detecting the recording sheet circulation period during the formation of the toner image of each color or by detecting the recording sheet circulation period directly preceding it.