Patent ID: 7878497

Claim:
An image forming apparatus, comprising: an image forming apparatus main body; a sheet inserting device which is arranged to be detachable from the image forming apparatus main body and which inserts an insertion sheet between sheets on which images are formed; a post-processing device which performs a post-process to the sheets on which the images are formed at the image forming apparatus main body and the insertion sheet; a sheet conveying path which is arranged at the sheet inserting device and which conveys the sheets on which the images are formed at the image forming apparatus main body and the insertion sheet to the post-processing device; a sheet conveying portion which is arranged at the sheet conveying path and which conveys the sheets being capable of accelerating and decelerating; and a control portion which controls operation of the sheet conveying portion, wherein the control portion performs the control of accelerating sheet conveying speed of the sheets from the image forming apparatus main body from a predetermined conveying speed at the sheet conveying path, inserting the insertion sheet so as to follow a preceding sheet which is accelerated, and conveying the sheets from the image forming apparatus main body and the insertion sheet to the post-processing device after being decelerated to the predetermined conveying speed.