A transfer unit includes an endless belt member, belt support rollers, a frame, a meandering detecting sensor, an alignment adjusting mechanism, and a conveyance guide disposed on a downstream side of the belt member with respect to a recording-medium conveyance direction. The alignment adjusting mechanism, based on a detection result of the meandering detecting sensor, causes one end portion of a downstream-side belt support roller of the belt support rollers which is adjacent to the conveyance guide to move along the recording-medium conveyance direction. The alignment adjusting mechanism causes a first end portion of the conveyance guide disposed on a same side as the one end portion of the downstream-side belt support roller to move following movement of the one end portion of the downstream-side belt support roller, and thereby maintains a distance between the belt member and the conveyance guide constant.

An image forming apparatus includes an apparatus body including an image bearing member configured to bear a toner image, a transfer unit including a transfer portion configured to transfer the toner image born on the image bearing member onto a sheet, the transfer unit being pivotably supported with respect to the apparatus body, an opening/closing unit disposed at a position farther from the apparatus body than the transfer unit is, and openably and closably supported with respect to the apparatus body, and a positioning portion pivotably supported with respect to the apparatus body and configured to position the transfer unit with respect to the apparatus body. The positioning portion is entirely disposed further on an outer side in the apparatus body than a pivot center of the transfer unit in a horizontal direction.

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.

An image-forming apparatus includes a main body, a belt unit detachably attachable to the main body, a coupling and a restricting part. The belt unit includes: a first roller defining an axis extending in an axial direction, a second roller opposing the first roller in a first direction perpendicular to the axial direction, and a belt looped over the first roller and the second roller. The coupling is configured to move in the axial direction to come into engagement with the first roller for inputting a drive force into the first roller. The restricting part is provided on the main body and is configured to restrict the first roller from moving in a second direction perpendicular to the axial direction and the first direction when the belt unit is attached to the main body.

An image forming apparatus includes: a body; a cover openably attached to the body; an image bearer; a transferer attachable to the cover, the transferer including: a transfer roller facing the image bearer and displaceable between: a contact position at which the transfer roller comes into contact with the image bearer; or a separated position at which the transfer roller is separated from the image bearer; and a holder rotatably holding the transfer roller; and a biasing member to bias the transfer roller toward the image bearer to the contact position, a support shaft swingably supporting the holder; and a pressure receiver to receive the holder.

An image forming apparatus includes an intermediate transfer unit, a secondary transfer unit, and a positioner. The intermediate transfer unit includes an intermediate transferor to bear an image. The secondary transfer unit includes a secondary transfer member to transfer the image borne by the intermediate transferor to a medium. The positioner positions the secondary transfer unit with respect to the intermediate transfer unit. The positioner includes a first member and a second member. The first member is disposed in the intermediate transfer unit. The second member is attachable to and detachable from the secondary transfer unit.

An image forming apparatus includes an apparatus main body, an image bearing member unit, a transfer member, a supporting member, and a positioning member. The image bearing member unit and the transfer member are disposed attachable to and detachable from the apparatus main body. The supporting member includes a to-be-contacted portion configured to be in contact with a to-contact portion of the image bearing member unit. The to-be-contacted portion is movable from a first position to a second position by an attachment operation of the image bearing member unit to the apparatus main body, where the first position is a position to be in contact with the to-contact portion, the second position is a position different from the first position, and the second position is a position at which the supporting member is supported by the positioning member and the to-be-contacted portion is out of contact with the to-contact portion.

An image forming apparatus for forming an image on a sheet includes a rotatable image bearing member, a transfer roller, a fan, and a duct. The duct extends in a parallel direction to a shaft direction of the transfer roller and includes an inflow port to guide air. The duct further includes, in an area opposing the transfer roller, a first opening portion that is provided at a position closer to a first end side of the duct than to a second end side of the duct, and a second opening portion that is provided at a position closer to the second end side than to the first end side, in the parallel direction. The air supplied to the duct by the fan through the inflow port passes through the first opening portion and the second opening portion, and is supplied to the transfer roller.

An intermediate transfer unit includes an intermediate transfer belt, a housing, a grip, and a cover. The housing supports a plurality of stretching rollers stretching the intermediate transfer belt and has a downstream plate in a pull-out direction of the intermediate transfer unit. The downstream plate is orthogonal to the pull-out direction. The grip is on the downstream plate. The cover covers the downstream plate and has a hole to access the grip.

An image forming apparatus includes a unit horizontally insertable and drawable with respect to a main body frame, and a lock mechanism for the unit. The lock mechanism includes a lock member which has an engagement projection engageable with an engaged portion formed in the main body frame, and a biasing member which biases the lock member in a first direction toward engagement of the engagement projection with the engaged portion. Along with insertion of the unit, the lock member moves in a second direction, and when the unit is inserted to a predetermined position, biasing force of the biasing member causes the lock member to move in the first direction and the engagement projection engages with the engaged portion. By moving the lock member in the second direction, engagement between the engagement projection and the engaged portion is released to make it possible to draw the unit.