Patent ID: 6128459
Filing Date: 2000-10-03
Classification: G03G

Abstract:
A method of forming a color image on a recording sheet, comprising the steps of:forming more than one color image positional deviation detecting mark having a common pattern along a common axis, comprising,including on a conveying belt a first line of a first detecting mark in a main scanning direction by operating a first electrophotographic processing section disposed at a first position along said conveying belt, and including a second line of the first detecting mark on said conveying belt positioned at an inclined angle with respect to said first line,including a second detecting mark on said conveying belt parallel to said first line of said first detecting mark by operating a second electrophotographic processing section disposed at a second position along said common axis; anddetecting said first line and said second line of said first detecting mark and detecting said second detecting mark with a single detecting device having a light source, a slit, and a light accepting element, and determining a positional deviation, in the main scanning direction and a subscanning direction F, of images formed on said recording sheet by said first electrophotographic processing section and said second electrophotographic processing section based on a conveying speed of said conveying belt and when said single detecting device detects said first line and said second line of said first mark, and said second detecting mark, wherein the positional deviation in the sub-scanning direction F is determined based on the following calculation:F={(TM1-TK1)-TO}Vwherein TM1 is a time of detecting the first line of the first detecting mark, TK1 is a time of detecting the second detecting mark, TO is an ideal interval time, and V is the conveying speed of said conveying belt.