Patent ID: 6356718
Filing Date: 2002-03-12
Classification: G03G

Abstract:
An image forming apparatus comprising:a feeding section for feeding a recording medium; a first image forming unit respectively including a first image carrying body provided along said feeding section and arranged in contact with said feeding section, a first latent image forming section for forming a latent image on said first image carrying body, a first developing section for supplying toner of first color to the latent image formed on said first image carrying body by said first latent image forming section to develop the same, and a first transfer section for transferring the toner image developed by said first developing section on the recording medium fed by said feeding section; a second image forming unit respectively including a second image carrying body having a larger diameter than said first image carrying body, provided along said feeding section in a succeeding stage of said first image forming unit and arranged in contact with said feeding section, a second latent image forming section for forming a latent image on said second image carrying body, a second developing section for supplying toner of second color to the latent image formed on said second image carrying body by said second latent image forming section to develop the same, and a second transfer section for transferring the toner image developed by said second developing section on the recording medium fed by said feeding section; a first rotating section for rotating said first image carrying body; a second rotating section for rotating said second image carrying body; a first output section for outputting an encode pulse with a preset number of pulses for one revolution based on a first encoder provided on a rotating shaft of said first rotating section; a second output section for outputting an encode pulse with a preset number of pulses for one revolution based on a second encoder provided on a rotating shaft of said second rotating section; converting means for converting an encode pulse from said second output section to a multiplied or frequency-divided pulse based on a difference between the diameters of said first, second image carrying bodies; alteration means for multiplying or dividing the encode pulse from the second output section by a value obtained by dividing the diameter of the second image carrying body with the diameter of the first image carrying body; a first control section for controlling rotation of said first rotating section at the rate of rotation based on the encode pulse from said first output section; a second control section for controlling said second rotating section at the rate of rotation based on a pulse determined by the alteration means; and a fixing section provided along said feeding section in a succeeding stage of said second image forming unit, for fixing the toner image transferred on the recording medium; and characterized in that said first and second rotating sections are independent of each other, and the circumferential thereof are controlled to be constant.