Patent ID: 8634749

Claim:
An image forming apparatus configured to transfer development agent onto a sheet to electrophotographically form an image on the sheet, comprising: a photoconductive drum configured to carry the development agent to be transferred onto the sheet; an exposure unit configured to expose the photoconductive drum; a development roller configured to supply the development agent to the photoconductive drum exposed by the exposure unit and develop the photoconductive drum; a feed tray configured to accommodate the sheet to be fed to the photoconductive drum; a sheet feeding unit configured to feed the sheet placed on the feed tray to the photoconductive drum; a registration roller disposed on a feeding pathway from the feed tray to the photoconductive drum, the registration roller being configured to stop the feeding of the sheet by the sheet feeding unit once and adjust timing for transferring the development agent onto the sheet; a first detector disposed downstream relative to the registration roller in a feeding direction, the first detector being configured to detect an existence of the sheet ejected from the registration roller; a circumferential velocity switching mechanism configured to switch a circumferential velocity of the development roller between a first circumferential velocity and a second circumferential velocity lower than the first circumferential velocity; and a controller configured to: determine a moment for switching the circumferential velocity of the development roller from the second circumferential velocity to the first circumferential velocity based on a moment when the controller issues, to the sheet feeding unit, an instruction to start feeding of the sheet; and determine a moment for switching the circumferential velocity of the development roller from the first circumferential velocity to the second circumferential velocity based on a moment when the first detector detects the existence of the sheet ejected from the registration roller.