Patent ID: 8130248

Claim:
An image forming apparatus having a photosensitive element, comprising: a light source for scanning light to the photosensitive element; a light blocking member disposed in a light traveling path of the light from the light source and moving between a blocking position to block the light scanned from the light source and a withdrawal position to withdraw from the blocking position; a power supply unit for supplying electric power to the light source for scanning light; a power switch unit for regulating power supply from the power supply unit; a single operating part for locating the light blocking member at the blocking position and controlling the power switch unit to cut off the power supply in a predetermined exposure condition; a main housing and a developing unit having the photosensitive element and detachably mounted in the main housing, the developing unit including an actuating member which positions the light blocking member at the withdrawal position for actuating the operating part to move to a predetermined operating position in order for the power switch unit to allow the power supply when the developing unit is mounted in the main housing, and positions the light blocking member at the blocking position and releases the operating part to move to a predetermined safety position in order for the power switch unit to cut off the power supply when the developing unit is detached from the main housing; and a frame to support the light source, the operating part being hinged to the frame and rotated between the operating position and the safety position by the actuating member.