Image forming apparatus capable of changing image forming modes during

Abstract

The present invention relates to an image forming apparatus for carrying out image forming in any of a plurality of image forming modes by changing the relationship between the drive starting time of the document scanner and the time at which registration rollers feed paper to the image forming unit. The paper feeding unit is adapted to feed paper from a paper housing unit at predetermined time intervals, determined according to the sizes of paper. The time intervals at which the registration rollers feed paper to the image forming unit are equal to these predetermined time intervals. Such predetermined time intervals remain unchanged for all image forming modes. Further, the period of time during which paper is once stopped by the registration rollers remains unchanged even though the image forming mode is changed. Accordingly, in a series of image forming operations, the time at which the registration roller feed paper to the image forming unit remains unchanged in any image forming mode or even though the image forming mode is changed. When the image forming mode is changed, it is required to change accordingly the relationship between the time at which the registration roller feed paper and the drive starting time of the document scanner. Such a change is made solely by changing the drive starting time of the document scanning means.