Abstract: A sheet conveyance device for conveying a recording medium includes a fixed roller, a movable roller, an urging member, and a shock absorber, and an image forming apparatus including the sheet conveyance device. The position of the fixed roller is fixed. The movable roller is disposed opposite the fixed roller to contact the fixed roller, thereby defining a nip. The urging member urges the movable member to contact the fixed roller in the absence of the recording medium in the nip and allows the movable member to separate from the fixed roller by an amount corresponding to a thickness of a recording medium when the recording medium enters the nip. The shock absorber absorbs displacement energy generated when the urging member urges the movable roller to contact the fixed roller again after the recording medium passes through the nip.

Abstract: A rotary body driver includes a driving source and a planetary gear transmission to receive a driving force from the driving source. The planetary gear transmission includes a sun gear rotatable by the driving force received from the driving source, a plurality of planet gears meshed with and surrounding the sun gear with an identical interval between the adjacent planet gears, a rotatable carrier to rotatably support the plurality of planet gears, an outer gear encircling and meshed with the plurality of planet gears, and an output shaft combined with and supporting the carrier. A rotary body shaft mounting a rotary body is connected to the output shaft of the planetary gear transmission to transmit the driving force received from the output shaft to the rotary body. The outer gear is made of resin and the output shaft and the carrier are made of metal.

Abstract: A drive transmission unit includes a planetary gear mechanism. The planetary gear mechanism includes an outer gear rotatably disposed on a shaft, a sun gear rotated by a power source, coaxially disposed on the same shaft as the outer gear, multiple planetary gears to engage the sun gear and the outer gear, disposed along an inner circumferential surface of the outer gear, a carrier rotatable on the same shaft as the outer gear to rotatably support the planetary gears, a contact member that contacts the sun gear as the sun gear moves in a direction of thrust due to engagement with the plurality of planetary gears, and a grease retaining portion to retain grease near a contact portion at which the sun gear contacts the contact member as the sun gear moves in the direction of thrust. The outer gear, the sun gear, and the planetary gears are helical gears.

Abstract: A drive device including a planetary gear reduction device having at least two stages and an output shaft, and a driven shaft to support a driven member rotatively driven by torque reduced by the planetary gear reduction device and transmit the torque from the output shaft to the driven member. Each stage of the planetary gear reduction device includes a sun gear, an outer gear, multiple planetary gears, a carrier, and a support shaft. The output shaft is provided to the carrier of the last stage. Central axes of the sun gear, the outer gear, the carrier, the output shaft, the driven shaft, and the driven member are all arranged coaxially with one another and at least one carrier is floatingly supported relative to the outer gear. The carrier is formed as a single integrated unit having holes into which both ends of the support shaft are fitted.

Abstract: A driving device includes a drive source, a planetary gear decelerator, a drive-target shaft, a rotation speed detector, and a sensor mount. The planetary gear decelerator includes a planetary gear mechanism equipped with an output shaft, a sun gear, an outer gear, a plurality of planetary gears, and a rotatable first carrier. The outer gear is made of resin and includes a deformable portion at a drive target side, and the deformable portion is elastically deformable in a radial direction. The plurality of planetary gears engages the sun gear and the outer gear. The rotatable first carrier rotatably supports the planetary gears. The rotation speed detector detects a rotation speed of the planetary gear decelerator, and includes a sensor and a detection target disposed coaxially on the output shaft. The sensor mount supports the sensor and moves in the radial direction in accordance with elastic deformation of the outer gear.

Abstract: A rotating-body driving device comprising: a rotating body; a driving source; a reduction gear that includes an output shaft and a gear rotating at a non-integer ratio of rotation period to a rotation period of the output shaft, and the reduction gear reducing rotation speed of the driving source; a pulse-signal generating unit; a pulse-count storage unit; a speed-fluctuation storage unit that stores therein a rotation speed fluctuation of the output shaft; and a driving-source control unit, wherein the driving-source control unit detects the speed fluctuation information associated with the accumulated number of pulse signals from the speed-fluctuation storage unit, and performs for the driving source a feedforward control to set off the rotation speed fluctuation.

Abstract: A planetary gear mechanism includes a plurality of planetary gears, an outer gear, a sun gear, a carrier, and a stick mount. The outer gear meshes with the plurality of planetary gears. The sun gear is coaxially disposed on the same axis as the outer gear and transmits force to the planetary gears. The carrier rotatably supports the plurality of planetary gears and is rotatably and floatingly supported. The carrier includes a hole through which a stick member penetrates in a direction of axis of rotation of the carrier. The stick member penetrates through the hole and is mounted on the stick mount. The stick mount is disposed opposite the carrier. The outer gear and the sun gear are held such that one of the outer gear and the sun gear does not rotate.

Abstract: A planetary gear unit including a sun gear rotatable by torque from a drive source, an outer gear disposed coaxially with the sun gear, multiple planetary gears disposed within the outer gear at equal intervals along an inner circumference of the outer gear to engage the sun gear and the outer gear, a carrier pin to rotatably support each of the multiple planetary gears, and a carrier rotatable coaxially with the sun gear and the outer gear to support both ends of the carrier pin. At least a first end of the carrier pin is constructed of a circular portion and a linear portion to form a first supported part. The carrier includes a first support part that supports the first supported part and is formed to position the circular portion of the first supported part downstream from the linear portion in a direction of rotation of the carrier.

Abstract: An image forming apparatus includes an endless belt member; a drive unit moving the endless belt member; a first detecting unit detecting a rotating speed of the drive unit; a second detecting unit detecting an endless transport speed of the endless belt member; and a control unit controlling the rotating speed of the drive unit based on a first detection signal from the first detecting unit or a second detection signal from the second detecting unit selectively depending on a selection condition. Upon selection of the first detection signal in accordance with the selection condition, the control unit corrects the rotating speed of the drive unit using the second detection signal such that an average value of the endless transport speed of the endless belt member approaches a target average value.

Abstract: A rotary body driver includes a driving source and a planetary gear transmission to receive a driving force from the driving source. The planetary gear transmission includes a sun gear rotatable by the driving force received from the driving source, a plurality of planet gears meshed with and surrounding the sun gear with an identical interval between the adjacent planet gears, a rotatable carrier to rotatably support the plurality of planet gears, an outer gear encircling and meshed with the plurality of planet gears, and an output shaft combined with and supporting the carrier. A rotary body shaft mounting a rotary body is connected to the output shaft of the planetary gear transmission to transmit the driving force received from the output shaft to the rotary body. The outer gear is made of resin and the output shaft and the carrier are made of metal.

Abstract: A drive transmission unit includes a planetary gear mechanism. The planetary gear mechanism includes an outer gear rotatably disposed on a shaft, a sun gear rotated by a power source, coaxially disposed on the same shaft as the outer gear, multiple planetary gears to engage the sun gear and the outer gear, disposed along an inner circumferential surface of the outer gear, a carrier rotatable on the same shaft as the outer gear to rotatably support the planetary gears, a contact member that contacts the sun gear as the sun gear moves in a direction of thrust due to engagement with the plurality of planetary gears, and a grease retaining portion to retain grease near a contact portion at which the sun gear contacts the contact member as the sun gear moves in the direction of thrust. The outer gear, the sun gear, and the planetary gears are helical gears.

Abstract: A drive device including a planetary gear reduction device having at least two stages and an output shaft, and a driven shaft to support a driven member rotatively driven by torque reduced by the planetary gear reduction device and transmit the torque from the output shaft to the driven member. Each stage of the planetary gear reduction device includes a sun gear, an outer gear, multiple planetary gears, a carrier, and a support shaft. The output shaft is provided to the carrier of the last stage. Central axes of the sun gear, the outer gear, the carrier, the output shaft, the driven shaft, and the driven member are all arranged coaxially with one another and at least one carrier is floatingly supported relative to the outer gear. The carrier is formed as a single integrated unit having holes into which both ends of the support shaft are fitted.

Abstract: A main controlling part is configured to choose and execute either a constant belt speed control which controls a driving motor (a driving source for an intermediate transfer belt) to move the intermediate transfer belt at a predetermined target belt speed or a constant motor speed control which rotates the driving motor at a predetermined target rotational speed according to a print command, and then, prior to a first-time print job, after executing a writing position correcting process while moving the intermediate transfer belt under the constant belt speed control, forms a color shift detecting image by switching from the constant belt speed control to the constant motor speed control, measures a difference between amounts of color shift, and executes a speed correcting process for correcting the target rotational speed of the driving motor in the constant motor speed control based on the measurement result.

Abstract: A printer according to the present invention is a so-called tandem-type printer, and has a configuration that a motor gear is directly connected to an M-photoconductor driving gear and an idler gear is directly connected to a Y-photoconductor driving gear and the M-photoconductor driving gear. A diameter of the Y and M photoconductors driving gear, a distance between transfer sections of the Y and M photoconductors, a motor gear input angle, and an idler input angle are set so that an absolute value of a value obtained by subtracting 1 from an ideal amplitude ratio, which indicates a ratio of an ideal amplitude of an eccentric component of the Y-photoconductor driving gear to an actual amplitude of an eccentric component of the M-photoconductor driving gear, is equal to or less than a maximum allowable amplitude ratio.

Abstract: In an image forming apparatus, a rotation detector detects an angular velocity or an angular displacement of a shared drive motor, or an angular velocity or an angular displacement of a photosensitive element. A drive control unit executes a process for controlling a drive speed of a drive source of the photosensitive element based on a result of detection by the rotation detector.

Abstract: A multicolor imaging system includes a controller which adjusts a phase difference in rotations of photoreceptors based on information detected by a rotary position detector, and drive elements for photoreceptors which generate a velocity fluctuation in the same cycle as that of a transfer unit. The controller is configured to concurrently adjust the phases of the photoreceptors and those of the drive elements so that a registration error in four color toner image on an intermediate transfer belt is reduced to a minimum.

Abstract: A planetary gear unit including a sun gear rotatable by torque from a drive source, an outer gear disposed coaxially with the sun gear, multiple planetary gears disposed within the outer gear at equal intervals along an inner circumference of the outer gear to engage the sun gear and the outer gear, a carrier pin to rotatably support each of the multiple planetary gears, and a carrier rotatable coaxially with the sun gear and the outer gear to support both ends of the carrier pin. At least a first end of the carrier pin is constructed of a circular portion and a linear portion to form a first supported part. The carrier includes a first support part that supports the first supported part and is formed to position the circular portion of the first supported part downstream from the linear portion in a direction of rotation of the carrier.

Abstract: A driving device includes a shaft member and a driven gear rotatably disposed to the shaft member that is formed to be fixed to a surface plate member inside the driving device. The shaft member is provided with a flow passage for air penetrating along a shaft line thereof. A cavity is formed in a bearing member of the driven gear to be spaced from the shaft member.

Abstract: A driving motor for a color black is shared between a photosensitive body for the color black and a driving roller that drives an intermediate transfer belt not shown. Furthermore, a driving motor for colors yellow, magenta, and cyan is shared between photosensitive bodies for the colors yellow, magenta, and cyan. Driving of the driving motor for the colors yellow, magenta, and cyan is controlled based on a first waveform as a speed fluctuation waveform of the photosensitive body for the color black obtained when the driving motor for the color black is driven at a predetermined speed and second waveforms as speed fluctuation waveforms of the photosensitive bodies for the colors yellow, magenta, and cyan obtained when the driving motor for the colors yellow, magenta, and cyan is driven at a predetermined speed.

Abstract: An image forming apparatus that includes at least one process cartridge having a photosensitive element, a development unit, a toner storage unit, a driven shaft and a driven gear mounted thereon and which is detachably attachable to the apparatus from a top front side thereof, a drive shaft, a drive gear mounted on the drive shaft to couple with and drive the driven gear to transmit a driving force to the process cartridge, an upper cover opening and closing with respect to the apparatus, a front cover opening and closing with respect to the apparatus, and at least one block component to block coupling of the drive gear and the driven gear by contacting the driven shaft while interlocked with opening and closing of the upper cover. The process cartridge is detachably attachable to the apparatus from the front top side thereof by opening and closing the upper cover.