Patent ID: 7751748

Claim:
An image-forming device comprising: a plurality of photosensitive drums, each being in a cylindrical shape having a circumferential surface, a side surface and an axis extending from the side surface, each photosensitive drum being rotatable around the corresponding axis; a plurality of drum gears provided in one-to-one correspondence with the plurality of photosensitive drums, each drum gear coaxially fixed to the axis of each photosensitive drum to be rotatable therewith, each drum gear having drum gear teeth and a first target portion; a scanning unit that exposes the circumferential surface of each photosensitive drum to light to form an electrostatic latent image thereon; a plurality of developing units disposed in one-to-one correspondence with the plurality of photosensitive drums, each developing unit storing a colored developer and supplying the corresponding circumferential surface with the developer to develop the corresponding electrostatic latent image; a transferring unit that transfers the developed image on the circumferential surface of each photosensitive drum onto an image receiving member; a casing that accommodates the plurality of photosensitive drums, each photosensitive drum being removable from the casing individually; a plurality of drive gears disposed in one-to-one correspondence with the plurality of drum gears and provided on the casing, each drive gear having drive gear teeth and a second target portion, the drive gear teeth being meshingly engageable with the drum gear teeth of the corresponding drum gear; and a removal allowing unit that allows each photosensitive drum to be removed individually from the casing, and each corresponding drum gear and drive gear to be disengaged individually, only when the first target portion of the drum gear is positionally in coincidence with a first position and when the second target portion of the drive gear is positionally in coincidence with a second position.