Abstract: An image forming apparatus includes a drum unit, a developing unit, a developing roller bearing, a guide portion, and an urging portion. The drum unit includes a photosensitive drum. The developing unit includes a developing roller. The developing roller bearing supports the developing roller and can move radially and rotate axially with respect to the developing unit. The guide portion is formed in the drum unit and guides the developing roller bearing in directions toward and away from the photosensitive drum. The urging portion urges the developing unit in such a direction that it presses the developing roller against the photosensitive drum. The developing unit includes a restriction portion that restricts the rotation of the developing roller bearing with respect to the developing unit within a predetermined range.

Abstract: A drive transmission mechanism includes a drive input gear part, an output side coupling and a coil spring. The drive input gear part includes a cylindrical boss formed on a rotational center. The drive input gear part is coupled to a drive input side gear. The output side coupling is rotated together with the drive input gear part around a same rotational axis as the drive input gear part to output a drive force of the drive input gear part to a driven member. The coil spring biases the output side coupling to a direction separated away from the drive input gear part along the rotational axis. The drive input gear part and the output side coupling are rotatable around a slide pin inserted into a slide hole formed in the boss as the rotational axis. The coil spring is held between the output side coupling and the slide pin.

Abstract: An image forming apparatus includes a power transmission member, a bias portion, a cam, and an interlocking mechanism. The power transmission member is displaceable between connected and released positions where the power transmission member is respectively connected to and disconnected from the detachable portion, and transmits the driving force of a drive portion to the detachable portion while connected to the detachable portion. The bias portion biases the power transmission member in a first direction to the connected position. The cam pivots from a first position to a second position to displace the power transmission member from the connected position to the released position, and is biased by the bias portion in a second direction to the first position when in the second position. The interlocking mechanism causes the cam to pivot from the first to the second position as a cover member changes its state from closed to open.

Abstract: An image forming apparatus includes a power transmission member, a bias portion, a cam, and an interlocking mechanism. The power transmission member is displaceable between connected and released positions where the power transmission member is respectively connected to and disconnected from the detachable portion, and transmits the driving force of a drive portion to the detachable portion while connected to the detachable portion. The bias portion biases the power transmission member in a first direction to the connected position. The cam pivots from a first position to a second position to displace the power transmission member from the connected position to the released position, and is biased by the bias portion in a second direction to the first position when in the second position. The interlocking mechanism causes the cam to pivot from the first to the second position as a cover member changes its state from closed to open.

Abstract: A drive transmission mechanism includes a drive input gear part, an output side coupling and a coil spring. The drive input gear part includes a cylindrical boss formed on a rotational center. The drive input gear part is coupled to a drive input side gear. The output side coupling is rotated together with the drive input gear part around a same rotational axis as the drive input gear part to output a drive force of the drive input gear part to a driven member. The coil spring biases the output side coupling to a direction separated away from the drive input gear part along the rotational axis. The drive input gear part and the output side coupling are rotatable around a slide pin inserted into a slide hole formed in the boss as the rotational axis. The coil spring is held between the output side coupling and the slide pin.

Abstract: A driving force transmission device includes a clutch, an output shaft, a bearing and an annular shim. The clutch is capable of being switched between a transmission of a rotational force and an interruption of the transmission of the rotational force. The output shaft outputs the rotational force of the clutch. The bearing supports an end portion of the output shaft with grease. The annular shim is disposed around the end portion of the output shaft between the clutch and the bearing. The shim has a through hole through which the end portion of the output shaft is inserted. The through hole has the same shape as a cross section of the end portion of the output shaft. A circumferential edge of the through hole comes into tightly contact with an outer circumferential face of the end portion of the output shaft.

Abstract: An image forming apparatus includes an image forming apparatus body, a photosensitive drum, a developing part developing an electrostatic latent image formed on a peripheral surface of the photosensitive drum into a toner image by supplying a toner, a transfer part transferring the toner image from the peripheral surface of the photosensitive drum onto a sheet, and a fixing part fixing the toner image transferred on the sheet. The photosensitive drum, the developing part, the transfer part, and the fixing part are unitized as an image-formation-related unit and the image-formation-related unit is detachably housed in the image forming apparatus body.

Abstract: A power transmission mechanism includes a driving gear and a driven gear. The driving gear includes a teeth portion and a tooth-chipped portion. The driven gear is intermittently driven transitioning between a meshing state and a non-meshing state. An interval between a first tooth and a second tooth of the driven gear is wider than an interval between teeth of the driven gear that are, starting with the second tooth, on an upstream side of the first tooth in a rotation direction of the driven gear. When the non-meshing state transitions to the meshing state, the first tooth abuts on a tooth of the driving gear that is, in the teeth portion, on a most downstream side in a rotation direction of the driving gear, and the second tooth is the 2nd tooth counted from the first tooth toward the upstream side in the rotation direction.

Abstract: A power transmission mechanism includes a driving gear and a driven gear. The driving gear includes a teeth portion and a tooth-chipped portion. The driven gear is intermittently driven transitioning between a meshing state and a non-meshing state. An interval between a first tooth and a second tooth of the driven gear is wider than an interval between teeth of the driven gear that are, starting with the second tooth, on an upstream side of the first tooth in a rotation direction of the driven gear. When the non-meshing state transitions to the meshing state, the first tooth abuts on a tooth of the driving gear that is, in the teeth portion, on a most downstream side in a rotation direction of the driving gear, and the second tooth is the 2nd tooth counted from the first tooth toward the upstream side in the rotation direction.

Abstract: A driving mechanism includes a first gear mechanism, a motion conversion mechanism, an actuator, and a mechanical clutch. The mechanical clutch includes an input gear that includes a plurality of engaging portions engageable with a displaced portion on a first position. The mechanical clutch switches to a connected state and a non-connected state corresponding to whether or not the engaging portions each engage with the displaced portion of the actuator. The connected state is a state where the rotational power of the first gear mechanism is transmitted to the motion conversion mechanism. The non-connected state is a state where the rotational power of the first gear mechanism is not transmitted to the motion conversion mechanism. The plurality of engaging portions are formed on a plurality of positions within a range of a default center angle less than 180 degrees in a circumferential direction of the input gear.

Abstract: A drive transmission device includes a driving power receiver, a first rotator drive transmission system, and a second rotator drive transmission system. The driving power receiver directly receives the driving power from an output shaft of the drive motor. The first rotator drive transmission system is configured to transmit the driving power from the driving power receiver to the respective first rotators of the first structure and the second structure. The second rotator drive transmission system is configured to switch a state of transmission of the driving power from the driving power receiver into a first transmission state in which the driving power is transmitted to the respective second rotators of the first structure and the second structure, and into a second transmission state in which the driving power is transmitted to the second rotator of the first structure alone.

Abstract: An image forming apparatus includes a driven unit, a coupling mechanism, a driving lever and a locking mechanism. The driven unit is configured to be supported slidably between a storage position and a pull-out position. The driving unit is driven by a driving force from a driving source. The coupling mechanism is configured to be switchable between a transmission state and a transmission release state. The driving lever is slidable between a transmission position and a transmission release position. The locking mechanism is configured to prevent the sliding of the driving lever from the transmission release position toward the transmission position. The sliding of the driving lever from the transmission release position into the transmission state can be permitted by the sliding of the driven unit from the pull-out position into the storage position.

Abstract: An image forming apparatus includes an apparatus main body, a plurality of photoreceptor drums, a plurality of developing devices, a frame, an intermediate transfer unit, a secondary transfer roller, first positioning portions, and second positioning portions. The secondary transfer roller forms a secondary transfer nip portion with the first roller where the toner images are transferred to a sheet. The first positioning portions are arranged at the intermediate transfer unit and the frame. The first positioning portions position the intermediate transfer unit in a second direction inside the apparatus main body. The second positioning portions are arranged at the intermediate transfer unit and the apparatus main body. The second positioning portions position a distal end side in the mounting direction of the intermediate transfer unit in a third direction inside the apparatus main body. The third direction intersects with the first direction and the second direction.

Abstract: A driving mechanism includes a first gear mechanism, a motion conversion mechanism, an actuator, and a mechanical clutch. The mechanical clutch includes an input gear that includes a plurality of engaging portions engageable with a displaced portion on a first position. The mechanical clutch switches to a connected state and a non-connected state corresponding to whether or not the engaging portions each engage with the displaced portion of the actuator. The connected state is a state where the rotational power of the first gear mechanism is transmitted to the motion conversion mechanism. The non-connected state is a state where the rotational power of the first gear mechanism is not transmitted to the motion conversion mechanism. The plurality of engaging portions are formed on a plurality of positions within a range of a default center angle less than 180 degrees in a circumferential direction of the input gear.

Abstract: A drive transmission device includes a driving power receiver, a first rotator drive transmission system, and a second rotator drive transmission system. The driving power receiver directly receives the driving power from an output shaft of the drive motor. The first rotator drive transmission system is configured to transmit the driving power from the driving power receiver to the respective first rotators of the first structure and the second structure. The second rotator drive transmission system is configured to switch a state of transmission of the driving power from the driving power receiver into a first transmission state in which the driving power is transmitted to the respective second rotators of the first structure and the second structure, and into a second transmission state in which the driving power is transmitted to the second rotator of the first structure alone.

Abstract: An image forming apparatus includes an apparatus main body, a plurality of photoreceptor drums, a plurality of developing devices, a frame, an intermediate transfer unit, a secondary transfer roller, first positioning portions, and second positioning portions. The secondary transfer roller forms a secondary transfer nip portion with the first roller where the toner images are transferred to a sheet. The first positioning portions are arranged at the intermediate transfer unit and the frame. The first positioning portions position the intermediate transfer unit in a second direction inside the apparatus main body. The second positioning portions are arranged at the intermediate transfer unit and the apparatus main body. The second positioning portions position a distal end side in the mounting direction of the intermediate transfer unit in a third direction inside the apparatus main body. The third direction intersects with the first direction and the second direction.

Abstract: An image forming apparatus has a registration roller pair, an upstream-side roller pair, a driving force source, a shared clutch, and an upstream-side roller stop delay mechanism. The upstream-side roller pair is provided on the upstream side of the registration roller pair with respect to the sheet transport direction. The driving force source generates a rotating driving force. The shared clutch engages and disengages the transmission of the rotating driving force from the driving force source to the registration roller pair and the upstream-side roller pair. When the transmission of the rotating driving force is disengaged by the shared clutch, the upstream-side roller stop delay mechanism delays the stopping of the upstream-side roller pair relative to the stopping of the registration roller pair.

Abstract: An image forming apparatus includes a driven unit, a coupling mechanism, a driving lever and a locking mechanism. The driven unit is configured to be supported slidably between a storage position and a pull-out position. The driving unit is driven by a driving force from a driving source. The coupling mechanism is configured to be switchable between a transmission state and a transmission release state. The driving lever is slidable between a transmission position and a transmission release position. The locking mechanism is configured to prevent the sliding of the driving lever from the transmission release position toward the transmission position. The sliding of the driving lever from the transmission release position into the transmission state can be permitted by the sliding of the driven unit from the pull-out position into the storage position.

Abstract: An image forming apparatus includes: a driving source including only a first driving motor and a second driving motor; a first transfer system that transfers a first driving force generated by the first driving motor; and a second transfer system that transfers a second driving force generated by the second driving motor. The first transfer system transfers the first driving force only to each image carrier and each developing roller. The second transfer system transfers the second driving force to at least a belt driving roller of an intermediate transfer unit, a fixing roller, and a sheet conveyance roller.

Abstract: A drive transmission mechanism includes an electromagnetic clutch and a drive output gear. The electromagnetic clutch includes a clutch shaft, a clutch input gear, a clutch idler gear, and a clutch output gear. The drive transmission mechanism transmits driving power using a first drive transmission path or a second drive transmission path. The first drive transmission path includes the clutch idler gear, a first idler gear, and a first output gear unit to transmit driving power to a rotated member connected to a first output gear unit irrespective of the energizing or the non-energizing an electromagnetic clutch. The second drive transmission path includes the clutch output gear, a second idler gear, and a second output gear unit to transmit driving power to a rotated member connected to the second output gear unit only when the electromagnetic clutch is energized.