Patent ID: 7715754
Filing Date: 2010-05-11
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a belt unit including a looped belt that circularly moves, the looped belt having a first surface outside of the loop and a second surface inside of the loop, and being stretched to form a substantially straight portion on the loop that extends in a first direction; a plurality of photosensitive drums, each having a circumferential surface on which an electrostatic latent image is formable, each circumferential surface being opposed to the straight portion of the first surface; a plurality of developing units disposed in one-to-one correspondence with the plurality of photosensitive drums, wherein each developing unit provides the circumferential surface of the corresponding photosensitive drum with developer in order to form a visible image thereon; a transfer unit opposed to the straight portion of the second surface, wherein the transfer unit transfers the visible image from the photosensitive drum onto either the first surface of the looped belt or a recording medium mounted on the first surface; a drum unit that holds the plurality of photosensitive drums and has a first projection member; a body accommodating the belt unit, the plurality of photosensitive drums, the plurality of developing units and the transfer unit, having a base surface extending in a second direction, and having a first predetermined position, a second predetermined position, and a third predetermined position; a drum unit holding unit that holds the drum unit at the first predetermined position, wherein each circumferential surface of the plurality of photosensitive drums contacts the straight portion of the first surface when the drum unit is held by the drum unit holding unit at the first predetermined position; a first guide unit that guides the first projection member to move the drum unit into the first predetermined position, and guides the first projection member in the second direction to move the plurality of photosensitive drums apart from the straight portion of the first surface when the drum unit is apart from the first predetermined position; a second guide unit that guides the belt unit into the second predetermined position, and guides the belt unit in a third direction opposite to the second direction when the belt unit is detached from the second predetermined position; and a cassette unit detachably provided at the third predetermined position to accommodate a recording medium on which an image is to be formed, the cassette unit being configured to be detachable from the third predetermined position in the first direction.