| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of suppressing color shift on the second line or later even when sudden or cyclic disturbance occurs, thereby suppressing the color shift in a whole image. <P>SOLUTION: A count value "y" of a sub-scanning synchronous signal and a count value "x" of a main scanning synchronous signal after detecting a color shift amount measurement start signal, and an elapsed time period "t" from the detection of the main scanning synchronous signal just before the detection of the sub-scanning synchronous signal to the detection of the sub-scanning synchronous signal are measured, and then the value "x" and the value "y" are approximated by a linear function: y=(1/α)x+β. The exposing of a first color on the first line is started at a timing of "x=xstart1", the exposing of a second color on the fist line is started at a timing of "x=xstart2" which is an integer nearest the value of "xstart1+β1-β2", the exposing of a third color on the fist line is started at a timing of "x=xstart3" which is an integer nearest the value of "xstart1+β1-β3", and the exposing of a fourth color on the fist line is started at a timing of "x=xstart4" which is an integer nearest the value of "xstart1+β1-β4". <P>COPYRIGHT: (C)2006,JPO&NCIPI |
