Patent ID: 6204866
Filing Date: 2001-03-20
Classification: G03G

Abstract:
An image forming apparatus comprising:a photosensitive drum turning at a constant angular velocity;means for writing an electrostatic latent image on said photosensitive drum using a laser beam having an intensity in accordance with image data output by an original reading unit which reads an original and outputs the image data thus obtained from said original or image data stored and read out from a memory;means for developing the electrostatic latent image formed on said photosensitive drum into a toner image; andan intermediate transfer belt running at a constant speed, onto which the toner image is transferred from said photosensitive drum, a reference mark being provided on said intermediate transfer belt;said memory for storing the image data output by said original reading unit;means for detecting said reference mark;means for counting pulses of a motor driving signal and outputting a count value, the pulses being used for driving a scanner motor provided in said original reading unit at different speeds so as to enable the original to be read at different speeds; andmeans for determining, based on the count value, a time period between a time said detecting means detects said reference mark and a time said writing means starts writing the electrostatic latent image on said photosensitive drum, when the electrostatic latent image is formed using the image data output by said original reading unit directly and the electrostatic latent image is formed using the image data stored and read out from said memory.