An image forming apparatus is provided, which includes a controller configured to determine a moment for switching a circumferential velocity of a development roller to a first circumferential velocity from a second circumferential velocity lower than the first circumferential velocity based on a moment when the controller issues to a sheet feeding unit an instruction to start feeding of a sheet, and to determine a moment for switching the circumferential velocity of the development roller to the second circumferential velocity from the first circumferential velocity based on a moment when a first detector detects existence of the sheet ejected from a registration roller.