Patent ID: 8559850

Claim:
An image forming apparatus comprising: a main casing; a belt unit supported by the main casing and including an endless belt and a plurality of transfer members; a photosensitive member unit including a plurality of photosensitive members disposed in one-to-one correspondence with the plurality of transfer members, electrostatic latent images being formable on each photosensitive member, each photosensitive member having an axis, the plurality of photosensitive members being arranged along a line extending in a direction orthogonal to an axial direction of each photosensitive member, the photosensitive member unit being loaded in the main casing; and a developing device unit including a plurality of developing devices disposed in one-to-one correspondence with the plurality of photosensitive members, each developing device including a developing member that supplies toner to a corresponding photosensitive member to develop the electrostatic latent images formed thereon and provide toner images, the toner images being transferred onto the endless belt by a corresponding transfer member, the photosensitive member unit being held in contact with the endless belt when the toner images are transferred onto the endless belt, the developing device unit being loaded in the main casing, wherein the main casing includes a first frame configured to support the developing device unit including the plurality of developing devices and a second frame configured to support both the belt unit and the photosensitive member unit including the plurality of photosensitive members, the second frame configured to move relative to the first frame such that both the belt unit and the photosensitive member unit including the plurality of photosensitive members move upward away from the developing device unit including the plurality of developing devices and move downward toward the developing device unit, wherein the second frame of the main casing is configured to support the belt unit and the photosensitive member unit including the plurality of photosensitive members, such that when the photosensitive member unit including the plurality of photosensitive members is separated from the developing device unit, the plurality of photosensitive members is separated from the belt unit supported by the second frame, and wherein the second frame is configured to support the photosensitive member unit including the plurality of photosensitive member, such that the photosensitive member unit including the plurality of photosensitive members is detachably attached in the main casing, while the belt unit is supported in the main casing.