Patent ID: 7860410

Claim:
A transfer device comprising: an intermediate transfer belt unit including an intermediate transfer belt for superposing toner images from a plurality of photoreceptors, one over another and a contacting/separating mechanism for putting the intermediate transfer belt into or out of contact with the plural photoreceptors; and, a detecting portion for performing detection of a contact/separation status between the photoreceptors and the intermediate transfer belt depending on the operational mode, inclusive of non-printing and printing modes and performing detection of the information for distinguishing a new intermediate transfer belt unit when the used intermediate transfer belt unit was replaced with a new unit, characterized in that the intermediate transfer belt unit includes a detection piece which makes the detecting portion detect the contact/separation status, and is changed in contact/separation status in accordance with the operational mode, by controlling and driving the contacting/separating mechanism, while the detecting portion includes: a sensor portion which detects the presence or absence of the detection piece based on the changing positional relationship of the detection piece as the contacting/separating mechanism moves; and a projection extending member which blocks light emitted from the sensor portion in order to detect whether the intermediate transfer belt unit was replaced with the new unit, wherein the projection extending member is arranged at a side of the detection piece when the intermediate transfer belt unit is the new unit while the projection extending member is rotatably pushed out by the detection piece when the intermediate transfer belt unit is in a used state, and based on the information detected by the sensor portion, gives notice of the contact/separation status between the photoreceptors and the intermediate transfer belt.