| 摘要 |
PROBLEM TO BE SOLVED: To prevent an image from shifting in position by specifying the relation between a distance measured from the electrostatic charging position of a photoreceptor up to primary transfer and a distance measured from the sensor position of an intermediate transfer body to a mark. SOLUTION: In a wait state before an image forming process is started, the distance measured from the electrostatic charging position 2 where an electrostatic charger 419 is arranged to a primary transfer part 1 in the direction of rotation of a photoreceptor drum 414 toward the downstream side shown by an arrow is denoted as (a) and the distance measured from the position of the sensor S to the mark M in the direction of rotation of an intermediate transfer belt 415 toward the upstream side shown by the arrow is denoted as (b); and relation of b>a is set. Consequently, electrostatic charging by the electrostatic charger 19 is started a certain time after the sensor S detects the mark M and then an image of a 1st color begins to be formed by optical writing. At this time, the front end part of an area which is placed in an electrostatically charged state by passing through the electrostatic charger 419 passes through the primary transfer part 1 and the position shift of the image due to the passage of an uncharged part can be eliminated. |
