Image forming apparatus having photosensitive drum moving mechanism

摘要

An image forming apparatus includes a main casing, a plurality of photosensitive drums, a retaining unit, and an endless belt. The retaining unit retains the plurality of photosensitive drums, and is movable between an internal position within the main casing and an external position outside of the main casing. The endless belt is configured to contact the plurality of the photosensitive drums, when the retaining unit is in the internal position and retains the plurality of the photosensitive drums therein. The retaining unit includes a plurality of pressing portions configured to exert pressure on the plurality of photosensitive drums toward the endless belt, when the retaining unit is in the internal position and retains the plurality of the photosensitive drums therein.

主权项

1. An image forming apparatus comprising:
a main casing; a photosensitive drum extending in an axial direction; an endless belt having a central portion, a first end and a second end in the axial direction; a retaining unit configured to detachably retain the photosensitive drum and being movable between an internal position within the main casing and an external position outside of the main casing, the retaining unit including:
a pressing member configured to exert pressure on the photosensitive drum toward the endless belt when the retaining unit retaining the photosensitive drum is located in the internal position;a first side wall positioned farther from the central portion in the axial direction than the first end of the endless belt; anda second side wall positioned farther from the central portion in the axial direction than the second end of the endless belt; and a moving member configured to move between a contact position and a separate position when the retaining unit retaining the photosensitive drum is in the internal position, the pressing member exerting upwardly the pressure on the photosensitive drum to bring the photosensitive drum into contact with the endless belt when the moving member is located in the contact position, the pressing member releasing the pressure on the photosensitive drum to separate from the endless belt when the moving member is located in the separate position, wherein the moving member has an upper surface on which the pressing member is provided, the moving member being positioned closer to the central portion in the axial direction than each of a portion of the first side wall and a portion of the second side wall is to the central portion in the axial direction.