A field replaceable transfer belt unit for toner-based printers includes a transfer belt and rollers for moving the transfer belt in a loop during a print operation, including a first roller configured to be driven by a driver shaft of a printer. The field replaceable transfer belt unit includes a rotatable handle for removing and replacing the field replaceable transfer belt unit from the printer. The rotatable handle is in communication with a drive cam that rotates to selectively engage and disengage the drive shaft with the first roller. Rotating the handle also secures the transfer belt unit to the printer.

An image forming apparatus includes a belt-shaped image bearer, a transferer, a guide, two rotators, and a support. The image bearer has an image bearing surface to bear an image thereon. The transferer forms a transfer section between the transferer and the image bearer, to transfer the image onto a recording medium. The guide is disposed upstream from the transfer section in a delivery direction of the recording medium, to guide the recording medium toward the transfer section. The two rotators are disposed upstream from the transfer section in a moving direction of the image bearer and in contact with a non-image bearing surface of the image bearer opposite to the image bearing surface, a first rotator being closer to the transfer section than a second rotator. The support supports the first rotator and the guide and adjusts a position of the first rotator and a position of the guide.

An image forming apparatus includes: a cover configured to be pivotal between a closed position and an open position to open an opening portion through which an intermediate transfer unit is removable, wherein when the cover is moved from an intermediate position to the open position, a secondary transfer unit is changed by using a self-weight of the secondary transfer unit from a first relative position to a second relative position, and wherein when the cover is located in the open position and the intermediate transfer unit is supported in a first position by a guiding portion, a secondary transfer unit interferes with the intermediate transfer unit if located in the first relative position, but does not interfere with the intermediate transfer unit if located in the second relative position.

A bearing device includes a first bearing for a first roller; a second bearing for a second roller; a bearing holder for the first and second bearings, wherein when the first bearing is mounted in the holder, a peripheral surface of the first roller is projected out of the holder through an opening of the holder, and the second roller is provided in the second bearing contacting the first roller in the holder; a contact portion for determining a relative position between the first and second bearings by contacting the first bearing with the first bearing mounted in the holder; and a moving mechanism for moving the second bearing toward the opening with dismounting of the first bearing, and for holding the second bearing in a position in which at least a part of a peripheral surface of the second roller projects out of the holder through the opening.

A roller unit includes: a first roller including, at one end, a shaft having a cut-out portion; a bearing that supports the shaft and forms a space for accommodating an object disposed in the cut-out portion; and a switching member including a shaft part that can be disposed in the cut-out portion, and a separating part that is continuous with the shaft part and that, when the shaft part is disposed in the cut-out portion, comes into contact with a unit including a second roller to separate the first and second roller. When the shaft part rotates with the shaft and moves from the cut-out portion to the space, the separating part comes out of contact with the unit, bringing the first roller and the second roller into a state in which the first roller and the second roller push each other.

An image forming apparatus includes a photosensitive member, a transfer unit having a transfer belt, a primary transfer roller, a secondary transfer inner roller below the primary transfer roller in a vertical direction, and a stretching roller, a secondary transfer outer roller, a support unit, and an air duct provided in the transfer unit. The secondary transfer outer roller faces the secondary transfer inner roller via the transfer belt and forms a nip portion for secondarily transferring a toner image on the transfer belt to a sheet. The air duct is located downstream of the nip portion in a sheet conveyance direction and below a portion of the transfer belt stretched between the secondary transfer inner roller and the stretching roller in the vertical direction. The air duct includes an air intake port and moves with the transfer unit with movement of the transfer unit from the support unit.

An image forming apparatus includes a photosensitive member, a transfer unit having a transfer belt, a primary transfer roller, a secondary transfer inner roller below the primary transfer roller in a vertical direction, and a stretching roller, a secondary transfer outer roller, a support unit, and an air duct provided in the transfer unit. The secondary transfer outer roller faces the secondary transfer inner roller via the transfer belt and forms a nip portion for secondarily transferring a toner image on the transfer belt to a sheet. The air duct is located downstream of the nip portion in a sheet conveyance direction and below a portion of the transfer belt stretched between the secondary transfer inner roller and the stretching roller in the vertical direction. The air duct includes an air intake port and moves with the transfer unit with movement of the transfer unit from the support unit.

An image forming apparatus includes an image forming portion, a belt unit including a cleaning unit and an opposing roller, and a swinging mechanism. The swinging mechanism includes a swingable member which is provided in a position different from a rotation center of the opposing roller while holding the opposing roller and the cleaning unit without changing a relative positional relationship between the opposing roller and the cleaning unit and which is swingable about a swing axis.

An image forming apparatus includes an opening-and-closing cover that is rotatable around a support shaft with respect to a body of the image forming apparatus. The opening-and-closing cover receives pressure in an opening direction from the body of the image forming apparatus when the opening-and-closing cover is closed and includes a rotation shaft rotatably held, a lock lever, and a pair of holding portions. The lock lever is rotatably disposed on the rotation shaft, is to be locked to or unlocked from a locking portion of the body of the image forming apparatus in conjunction with rotation of the rotation shaft, and includes a pair of held portions at both ends of the lock lever. The pair of holding portions are disposed to sandwich the lock lever from both sides of the lock lever in an axial direction of the rotation shaft and hold the pair of held portions.

A roller unit includes: a first roller including, at one end, a shaft having a cut-out portion; a bearing that supports the shaft and forms a space for accommodating an object disposed in the cut-out portion; and a switching member including a shaft part that can be disposed in the cut-out portion, and a separating part that is continuous with the shaft part and that, when the shaft part is disposed in the cut-out portion, comes into contact with a unit including a second roller to separate the first and second roller. When the shaft part rotates with the shaft and moves from the cut-out portion to the space, the separating part comes out of contact with the unit, bringing the first roller and the second roller into a state in which the first roller and the second roller push each other.