Light guide device, drum unit, image forming apparatus and image reading device including light guide device

A drum unit that is attached to an image forming apparatus for use, the drum unit comprising:

• a housing main body supporting a photoconductor drum rotatably;
• a pair of side plates provided at both longitudinal ends of the housing main body;
• a side member attached to an outer surface of a side plate on one longitudinal side among the pair of side plates;
• a light guide body supported at both longitudinal ends by the pair of side plates, including a light incident surface and a light exit surface, wherein light enters the light incident surface, the light exit surface emits light in a direction that crosses a direction in which the light enters the light incident surface, and the light guide body irradiates a charge removing light from the light exit surface toward the photoconductor drum;
• a projection provided on one longitudinal side of the light guide body and extending in a direction orthogonal to a longitudinal direction of the light guide body;
• a holding hole provided in the side plate on one longitudinal side, wherein one of the longitudinal ends of the light guide body is inserted in the holding hole;
• a light source substrate held between the side member and the side plate on one longitudinal side and including a light element that emits the light toward the light incident surface;
• and
• a positioning portion configured to position the light element to a reference position with respect to the light incident surface, wherein
• the positioning portion includes:
• an abutting member formed to stand on the outer surface of the side plate on one longitudinal side and including a tip end portion inserted in an engaging hole formed in the light source substrate;
• a rib provided on an outer peripheral surface of the abutting member and extending in a standing direction of the abutting member;
• and
• an elastic member held by the side member and configured to elastically press the light source substrate toward the light guide body to have the rib abut on a peripheral edge of the engaging hole so as to position the light element to the reference position.