Patent ID: 6184910
Filing Date: 2001-02-06
Classification: B41J,G06K

Abstract:
A color image forming apparatus comprising:an image carrier for causing a latent image to be electrostatically formed thereon;emitting means for emitting a light beam modulated by each of image signals of respective colors and representative of a document image;a rotatable polygonal mirror for steering said light beam to thereby electrostatically form latent images respectively associated with said image signals on said image carrier;drive means for causing said polygonal mirror to rotate;developing means for developing said latent images with developers of respective colors to thereby produce corresponding monocolor toner images;an intermediate transfer body formed with a plurality of marks for position detection, and for causing said monocolor toner images to be sequentially transferred thereto from said image carrier;sensing means located at a predetermined position for sensing said plurality of marks, and for generating an output in response to each sensed mark;first control means for masking said output corresponding to each sensed mark except for a selected mark which remains an unmasked mark, and for causing each of said latent images to begin to be formed based on a time when said sensing means senses said unmasked mark; andsecond control means for controlling a rotation phase of said polygonal mirror on the basis of the time when said sensing means senses said unmasked mark and for ensuring said monocolor toner images overlap one another without relative displacement on said intermediate transfer body.