Patent ID: 8121507
Filing Date: 2012-02-21
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: an image carrier for carrying a toner image; a transferring portion configured to transfer the toner image of the image carrier to a sheet material to obtain a transferred toner image; a fixing portion configured to fix the transferred toner image on the sheet material; a fixing and driving portion configured to send the sheet material with the transferred toner image to the fixing portion; a conveyance guide member configured to guide the sheet material with the transferred toner image to the fixing portion; a loop amount detecting portion configured to detect, in increments, a loop amount of the sheet material passing by the conveyance guide member; and a drive controller configured to carry out a drive control of the fixing and driving portion based on a detection result of the loop amount detecting portion, the loop amount detecting portion comprising at least one additional rotational position sensor and said rotational position sensor are respectively disposed in positions corresponding to respective trajectories of to-be-detected parts, and the image forming apparatus is configured to detect the rotational position of the detecting member by detecting the presence or absence of the to-be-detected parts in respective portions of the trajectories of said to-be-detected parts.