Image forming apparatus

An image forming apparatus comprising:

• a rotatable photosensitive member;
• a charging device configured to electrically charge said photosensitive member at a charging position under application of a voltage;
• an exposure device configured to expose said photosensitive member, charged by said charging device, to light at an exposure position thereby to form an electrostatic image on said photosensitive member;
• a developing device configured to develop the electrostatic latent image into a toner image by supplying toner to a region of said photosensitive member exposed by said exposure device;
• a transfer device configured to transfer the toner image from said photosensitive member onto a toner image receiving member at a transfer position under application of a voltage;
• and
• a controller capable of executing,
• an operation in a first mode in which an image forming operation is controlled so that an exposure start enable timing of said exposure device for a first sheet in an image forming job is set during movement of said photosensitive member through one full circumference from first passing, through the exposure position, of a region of said photosensitive member which has passed through the charging position when a DC voltage applied to said charging device with a start of image formation reaches a predetermined target voltage, and
• an operation in a second mode in which an image forming operation is controlled so that the exposure start enable timing is set after movement of said photosensitive member through one full circumference after first passing, through the exposure position, of the region of said photosensitive member which has passed through the charging position when the DC voltage applied to said charging device with the start of image formation reaches the predetermined target voltage,
• wherein on the basis of image information of the first sheet of the image forming job, said controller selects an executing mode from a plurality of modes including at least the first mode and the second mode.