Abstract: A rotation member unit detachable from a casing includes a rotation member for rotating when driven, and plural drive introduction members arranged at both ends of the rotation member in a rotation axial direction of the rotation member, respectively. The drive introduction member engages with a drive transmission member rotated by a motor.

Abstract: A driving device for a toner cartridge includes a cartridge body and a driving portion disposed on the cartridge body. A transmission mechanism is disposed in the cartridge body. The driving portion includes a driving motor and a controller. The controller receives signal transmitted from a controller unit of a printing apparatus to precisely control the operation of the driving motor. The driving motor is connected with the transmission mechanism. Through the driving action of the driving portion, the transmission load of the printing apparatus can be reduced, and the stability of the printing system can be improved. Moreover, because the driving portion is built in the cartridge body, the gear transmission mechanisms of both of the printing apparatus and the toner cartridge can be simplified, and malfunction can be solved.

Abstract: An image forming apparatus includes a photosensitive member that rotates and is subjected to exposure so that a latent image is formed thereon, a driver that rotates the photosensitive member, an exposure section that exposes the photosensitive member by irradiating the photosensitive member with light, a light intensity adjustment section that receives a part of the light from the exposure section and adjusts intensity of the light irradiated by the exposure section, and an adjustment controller that causes the driver to start rotating the photosensitive member and causes the light intensity adjustment section to start adjusting the intensity of the light after a rotation speed of the photosensitive member exceeds a predetermined threshold value.

Abstract: Described herein is an exemplary method wherein the photoreceptor surface velocity is nominally set at a speed fractionally different than the intermediate belt (ITB) nominal surface speed. The photoreceptor speed can be preemptively altered through a velocity ramp profile whenever an event is scheduled to occur that will result in ITB transient vibration. As a result, the photoreceptor speed is not allowed to cross over or equal the belt speed at any instant during the transient event. This allows the photoreceptor to remain dynamically decoupled from the ITB, since the apparent disturbance torque imposed by the belt remains constant and does not reverse sign.

Abstract: A belt driving controller includes a driving roller connected to a driving axis, a plurality of driven rollers, an endless belt provided to surround the driving roller and the driven rollers in a tensioned state, a motor connected to the driving axis via a reduction mechanism; a first detector provided near the driving axis and configured to detect a rotation angle of the driving axis, a second detector configured to detect a displacement of the endless belt, and a control unit configured to control driving of the endless belt.

Abstract: A drive apparatus includes a magnet rotor, a stator having a coil, a position detector configured to detect a position of the magnet rotor, a lead angle circuit configured to output a signal having a lead angle relative to an output of the position detector, a first driver configured to switch an electrification state of the coil in accordance with a preset time interval, a second driver configured to switch an electrification state of the coil in accordance with an output of the lead angle circuit, and a controller configured to adjust a lead angle amount of the signal output from the lead angle circuit within a range that does not cause step out in the driving by the first driver, prior to changing the driving by the second driver to the driving by the first driver.

Abstract: A unit detachably mountable to an apparatus main assembly is provided with a coupling for receiving a rotational driving force from the apparatus main assembly. Also the apparatus main assembly is provided with a coupling to be engaged with the coupling of the unit. At least one of these couplings can be pushed in a direction parallel to a rotation shaft and one of the couplings is provided with an inclined surface. During mounting and demounting of the unit, the engagement between the couplings is released by the pushing in of one of the couplings pushed by the inclined surface.

Abstract: A belt driving controller is disclosed. The belt driving controller controls driving of a belt that is wound around plural sustaining rollers by controlling a driving sustaining roller that transmits a driving force to the belt. In two sustaining rollers, a calculating method for recognizing a PLD (pitch line distance) of the belt is used. In the calculating method, the delay period during which the belt moves a distance from a driven sustaining roller having a large diameter to a driven sustaining roller having a small diameter is determined to be shorter than before in the belt moving direction.

Abstract: An image forming apparatus includes first and second rotatable image bearing members, a rotatable belt member which can abut on the first and second image bearing members, a drive mechanism to attach or separate the second image bearing member to or from the belt member, a rotation drive mechanism, and a controller controlling a rotational speed of the second image beating member so that the second image bearing member rotates with a predetermined circumferential speed difference with respect to the belt member at least when image formation is performed by the second image bearing member. When the second image bearing member abuts on or separates from the belt member, the controller controls the rotational speed of the second image bearing member so that a circumferential speed difference between rotational speeds of the second image bearing member and the belt member is smaller than the predetermined circumferential speed difference.

Abstract: Disclosed is an image forming apparatus, which makes it possible to appropriately conduct a controlling operation for eliminating the velocity fluctuation of the photoreceptor drum without generating any malfunction. The apparatus includes a photoreceptor member driven by a motor and a control section that is provided with a feed forward controlling section that stores parameters derived from driving errors for one revolution of the photoreceptor member to create a reverse-phase instruction value based on the parameters and a feedback controlling section that controls a velocity of the photoreceptor member, so as to keep the velocity of the photoreceptor member constant. During an initial operating time, the control section deactivates the feed forward controlling section, while only activates the feedback controlling section to drive the photoreceptor member so as to measure a driving toque of the driving motor, and selects a parameter from the parameters, corresponding to the driving toque measured.

Abstract: An image forming apparatus is configured to reduce a velocity fluctuation of a rotating body by reducing the AC velocity component of the rotating body. The image forming apparatus may include an image bearing body with a surface on which a toner image is formed; a driving motor configured to drive the image bearing body according to an input signal; and a controller configured to control the driving motor to output a motor output velocity at a period equal to that of an AC velocity component of the image bearing body. A velocity control method for the rotating body includes sampling a continuous motor input signal at a period equal to that of an AC velocity component of a rotating velocity of the rotating body. The sampled signal is transmitted to a driving motor that drives the rotating body, which is driven based upon the discrete motor input signal.

Abstract: An image forming apparatus includes at least one image bearing member unit including an image bearing member and a motor including an output shaft coupled with the image bearing member to rotary-drive the image bearing member. The output shaft of the motor includes rotation speed detecting means to detect a rotation speed of the output shaft, the rotation speed detecting means being disposed in a vicinity of a node of a torsion resonance mode of the output shaft of the motor.

Abstract: A traction-drive type driving-force transmission mechanism includes an output shaft and a sun roller that is rotatable about a first central axis. Shafts having respective second central axes are disposed respectively on corresponding secondary axes, of which is inclined relative to the first central axis in such a manner that each second central axis is aligned with the corresponding secondary axis. A pressing member is coupled to the output shaft. A plurality of speed-reduction rollers are disposed along an outer peripheral surface of the sun roller and are supported by the respective shafts. The pressing member presses each of the speed-reduction rollers against the outer peripheral surface of the sun roller to allow a driving force to be transmitted by a traction force between the sun roller and the speed-reduction roller.

Abstract: An image forming apparatus includes: a frame that includes a pair of standing walls spaced apart from each other, and a linking section linking the pair of standing walls; and an intermediate transfer section that includes support rolls extending between the pair of standing walls and supported by the pair of standing walls, and an intermediate transfer belt held by the support rolls and circulating. The apparatus further includes built-in bodies, at least, into each of which a photoreceptor roll having a shaft with protruding both ends and rotatable around the shaft is incorporated, and which are arranged along the intermediate transfer belt while being supported in a state that the both ends of the shaft penetrate the pair of standing walls, and each of which is fixed to a first standing wall of the pair of standing walls by a screw.

Abstract: A rotation driving force transmitting member is disposed between a motor section and a main body of a photoreceptor drum. The rotation driving force transmitting member has a convex member which is provided on the photoreceptor drum side and includes a twisted convex portion with an elliptical cross-section and a concave member which is provided on the motor section side and includes a twisted concave portion with an elliptical cross-section, the concave portion being fitted in the convex portion. The rotation driving force transmitting member transmits rotation driving force by the motor section to the photoreceptor drum via the convex member and the concave member in a state where the convex member is subjected to a drawing force toward the concave member side, due to rotation of the motor section in a state where the convex portion and the concave portion are fitted in each other.

Abstract: A constant-velocity joint includes an outer ring having an annular space therein and an opening at one axial end thereof. The annular space is defined by a radially outer wall and a radially inner wall of the outer ring. At least one of the radially outer wall and the radially inner wall has three axially extending track grooves circumferentially spaced apart from each other by 120 degrees. A cage is inserted in the annular space. The cage has pockets at positions corresponding to the track grooves, respectively. A ball is received in each of the pockets so as to roll along one of the track grooves. A pair of diametrically opposed protrusions is formed at radially inner and outer open ends of the pockets of the cage to prevent the balls from coming out of the pockets of the cage.

Abstract: A lottery ticket machine able to prevent tickets from being illegally drawn out includes a machine base provided with a driving device, two press rollers with pressed streaks on the wheel surface and a control device. One of the two press rollers is provided with a shaft extending out of the machine base for fixing the control device that contains a rotary gear with engage holes, a bushing and a control wheel bored with bushing hole to be fitted with the bushing and disposed with engage teeth and projecting members to be respectively engaged with the engage holes of the rotary gear. An outer cover covered on the control device is provided inside with engage teeth to correspondingly engage with the engage teeth of the control wheel, and a spring has opposite ends respectively pushing against the control wheel and the inner wall of the bushing cover.

Abstract: In a method to determine a curve of revolution speed of a continuous belt-shaped image substrate, at least two color separations are generated on the image substrate and transferred from the image substrate onto a substrate material to generate a print image. A first offset in a transport direction of the substrate material between the at least two color separations of the print image is determined at a first point. At least one second offset in the transport direction is determined between the at least two color separations of the print image at least one second point. The first point and the second point have at least one interval relative to one another in the transport direction. The curve of the revolution speed of the image substrate is determined with aid of the first offset and the second offset.

Abstract: A process cartridge is provided detachably mountable to a main assembly of an electrophotographic image forming apparatus. The process cartridge includes an electrophotographic photosensitive drum, a frame for supporting the electrophotographic photosensitive drum, a developing roller, and a developer supplying roller. The process cartridge further includes portions-to-be-supported, portions-to-be-positioned, a portion-to-be-urged, and a cartridge side developer supply roller bias contact. The process cartridge can be positioned with high accuracy relative to the main assembly of an image forming apparatus.

Abstract: A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus, which includes a rotating force applying portion. The cartridge includes an electrophotographic photosensitive drum, a developing roller, a first frame unit supporting the drum, a second frame unit supporting the roller and swingably connected with the first frame unit, a coupling, mounted to the drum, for receiving a rotating force for rotating the drum from the rotating force applying portion when the cartridge is mounted to the main assembly, first, second and third cartridge side portions to be positioned engageable respectively with first, second and third main assembly side positioning portions provided in the main assembly to regulate movement of the first frame unit in a longitudinal direction of the drum or to position the drum in a radial direction when the cartridge is mounted to the main assembly, and first unit side and drum side regulating portions.

Abstract: The belt driving mechanism of the present invention includes: a driving pulley; a driven pulley; a looped transmission belt extended over the driving pulley and the driven pulley; a first holding member that bearing-supports and holds the driving pulley; a second holding member that bearing-supports and holds the driven pulley, and is combined with the first holding member; and a biasing member that biases the first holding member and the second holding member to be separated, in a state in which the first holding member and the second holding member are combined.

Abstract: A connection assembly of the photo-conductor drum is applied for linking a driving shaft. The connection assembly of the photo-conductor drum includes a drum gear and a connector. A first connection part arranged at an end of the drum gear. An end of the connector forms a second connection part corresponding to the first connection part. Another end of the connector forms a joint end. The joint end includes a central pillar, and a plurality of protrusions extending from a periphery of the central pillar. The second connection part could detachably connect to the first connection part. The joint end is detachably connected to the driving shaft. Therefore, by replacing the damaged drum gear or damaged connector only, the costs, quantity of the waste and the maintenance expend would be reduced.

Abstract: An image forming apparatus is provided. The image forming apparatus comprises an apparatus main body; a process unit having a drive input member; and a drive transmission member, wherein, the drive transmission member comprises: a guide core member having a distal end core portion which has a first outside diameter; and a proximal end core portion which has a second outside diameter that is larger than the first outside diameter; a reciprocating member in which the guide core member is inserted, the reciprocating member comprising: a distal end cylindrical portion which has a first inside diameter; and a proximal end cylindrical portion which has a second inside diameter that is larger than the first inside diameter; and a pressing member interposed between the guide core member and the reciprocating member for connecting the guide core member and the reciprocating member.

Abstract: A fluctuation detecting unit detects a fluctuation of an endless belt generated when a sheet is brought into contact with a predetermined position of the endless belt at an upstream side in a conveying direction from a nip portion based on fluctuation information acquired by a fluctuation information acquiring unit. An entry timing estimating unit estimates entry timing of the sheet into the nip portion based on a detection of the fluctuation. A correction control unit corrects a speed fluctuation of the endless belt generated when the sheet enters the nip portion by performing a feedforward control of a first driving unit based on the entry timing.

Abstract: A drive gear for a generally cylindrical imaging component. The drive gear includes a body for engaging the generally cylindrical imaging component; a cylindrical shaft attached to the body, the cylindrical shaft having an end surface; and three prongs extending longitudinally outward from the end surface. Each prong may include an extension member extending perpendicular to the prongs and the cross-sectional area of the extension members may be less than the cross-sectional area of the prongs.

Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic image; a rotatable supporting member swingably supporting the rotatable supporting member, the rotatable supporting member being provided with a first gear portion and being rotatable while carrying a plurality of developing devices for developing the electrostatic image with toner; a drive transmission device for transmitting a rotational force to the rotatable supporting member, the drive transmission device being provided with a second gear portion engaged with first gear portion at an engagement position; and an opposing portion provided opposed to the rotatable supporting member with a gap therebetween which is smaller than an amount of engagement between the first gear portion and the second gear portion.

Abstract: An image forming apparatus includes a first photosensitive member and a second photosensitive member that form images having different colors, a transfer belt that transfers the images formed on the first photosensitive member and the second photosensitive member onto a recording sheet, a first motor that rotatingly drives the first photosensitive member and the transfer belt, and a second motor that rotatingly drives the second photosensitive member. After the startup process of the first and second motors has been completed, the rotation speed of the second motor is controlled while maintaining the rotation speed of the first motor unchanged so that the second rotation phase of the second photosensitive member rotatingly driven by the second motor is the same as the first rotation phase of the first photosensitive member rotatingly driven by the first motor.

Abstract: A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus including a driving shaft having a rotational force applying portion by moving in a direction substantially perpendicular to an axis of the driving shaft. The cartridge includes an electrophotographic photosensitive drum, a coupler engageable with the rotational force applying portion to receive a rotational force for rotating the drum and taking transmitting, pre-engagement, and disengaging positions, and a regulator regulating an inclination angle of the coupler. During cartridge mounting, the coupler moves from the pre-engagement to the transmitting position to oppose the driving shaft, and during cartridge dismounting, the coupler moves from the transmitting to the disengaging position to disengage from the driving shaft.

Abstract: A drive gear for a generally cylindrical imaging component. The drive gear includes a body for engaging the generally cylindrical imaging component; a cylindrical shaft attached to the body, the cylindrical shaft having an end surface; and three prongs extending longitudinally outward from the end surface.

Abstract: A process cartridge is provided that is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes a photosensitive drum and a developing roller. A coupling member is provided adjacent to one axial end of the developing roller, with the coupling member including a driven portion, an intermediary portion, and a driving portion. A retaining portion is also provided, with the retaining portion configured and positioned to retain an axis of the driving portion of the coupling member in a position that is deviated from the axis of the developing roller in a direction crossing the axis of the developing roller so as to enable engagement of the driving portion with a driving member of the image forming apparatus when the process cartridge is inserted into the main assembly of the apparatus with the developing roller being in contact with the photosensitive drum.

Abstract: An image forming apparatus including: a photoreceptor for bearing a toner image; a transfer body onto which the toner image borne by the photoreceptor is transferred; a drive section for driving the photoreceptor and transfer body respectively, and a control section for controlling the drive section so as to drive the photoreceptor and transfer body at a predetermined driving speed, wherein the control section, under a state in which the control section controls to drive the transfer body at the predetermined driving speed, controls to: a) drive the photoreceptor while changing the driving speed of the photoreceptor within a range of driving speeds between low speed and high speed, including the predetermined driving speed, b) extract torque characteristics under the control which includes the change of driving speed of the photoreceptor, and c) determine the driving speed of the photoreceptor based on the extracted torque characteristics.

Abstract: A drive transmission device includes drive transmission members including a detection target gear, a detection device detecting the rotational position of the target gear and including a position detection member and a detection unit, and a conductive protection member protecting the detection unit. The detection unit and the protection member are assembled to the same member to be installed to an external apparatus. If there is a dimensional error in the protection member causing a portion of the protection member closest to the target gear to shift in position relative to the detection unit beyond a predetermined range, the protection member comes into contact with the detection unit in the assembling process, and is corrected in shape by the detection unit, with the shift in position relative to the detection unit of the portion of the protection member closest to the target gear kept within the predetermined range.

Abstract: An image forming apparatus capable of preventing degradation of image quality and reducing time required for rotational phase control. Toner images different in color are formed on a plurality of photosensitive drums, respectively. The toner images are transferred onto an intermediate transfer belt in superimposed relation. A motor controller performs phase control for bringing phases of the respective photosensitive drums into predetermined relation based on a rotational phase difference detected using phase detection sensors. When the rotational phase difference is out of a predetermined range, the motor controller performs the phase control with the photosensitive drums and the intermediate transfer belt separated from each other, whereas when the rotational phase difference is within the predetermined range, the motor controller performs the phase control with the photosensitive drums and the intermediate transfer belt in contact with each other.

Abstract: In an image forming apparatus, an image forming portion forms an image on a rotator. A first designating portion determines a first estimated phase point based on a base time point, and designate, as a designated parameter, a correction parameter corresponding to said first estimated phase point based on change characteristics information stored in a storage portion. A correcting portion corrects an image forming position on the rotator based on the designated parameter. A changing portion changes a value of the designated parameter into an adjusted value intermediate between the designated parameter and a reference parameter that is a correction parameter designated based on the time when the detecting portion detects the detecting phase point.

Abstract: An image forming apparatus having a color mode and a monochromatic mode, which includes: a transmission member, which can be switched between a transmitted state where a motor transfers a drive force to a single photoreceptor drum and a non-transmitted state where the motor does not transfer the drive force to the single photoreceptor drum; and a controller which switches to the non-transmitted state while executing an image formation in the monochromatic mode, and when a command to execute a next image formation is not instructed, switches to the transmitted state after a phase adjustment of each photoreceptor drum after the image formation in the monochromatic mode, and controls the motor to execute a slight rotation operation at every prescribed period of time by synchronizing plural drums including the single photoreceptor drum with each other through the transmission member.

Abstract: Example embodiments relate to a constant velocity joint having an outer ring including an annular space with an open end, plural outer grooves axially extending in an outer wall of the annular space and being equally spaced from each other in a circumferential direction, and plural inner grooves axially extending in an inner wall of the annular space and facing the respective outer grooves, and a cage configured to hold balls that slide along the inner walls and the outer walls. The outer ring and/or the cage may be made of a synthetic resin. A drive force of one of the cage and the outer ring may be transmitted to the other one of the cage and the outer ring when part of the cage may be inserted in the annular space and the balls held by the cage may be engaged in the inner grooves and the outer grooves.

Abstract: The image forming apparatus includes a drum cartridge having a photosensitive drum and a drum drive input member; a developing cartridge configured to be movably mounted to the drum cartridge, the developing cartridge comprising a developing roller disposed so as to face the photosensitive drum and a developing drive input member; a drum drive transmission member configured to engage with the drum drive input member and configured to transmit drum driving force to the drum drive input member while permitting a positional gap of the drum drive input member within a predetermined range; and a developing drive transmission member configured to engage with the developing drive input member and configured to transmit developing driving force to the developing drive input member while permitting a positional gap of the developing drive input member within a predetermined range.

Abstract: The image forming apparatus includes: an apparatus body including a drive source; a driven member detachably attachable to the apparatus body; a first transmission member in the apparatus body, including a base rotatable around a rotation axis, and transmitting drive force from the drive source to the driven member; and a second transmission member in the driven member, including a base rotatable around the rotation axis, and transmitting drive force from the first transmission member to the driven member. Any of the first and second transmission members includes a projection, and the other includes a receiving port. The receiving port receives the projection when a rotation angle between the first and second transmission members is an angle set in advance while not receiving the projection when the rotation angle is out of the angle, at the time of mounting the driven member on the apparatus body.

Abstract: An image forming apparatus includes four image carriers, four image carrier gears provided corresponding to the respective image carriers, four transmission gears provided corresponding to the respective image carrier gears and meshed with the respective image carrier gears, and two driving sources each provided corresponding to a pair of the transmission gears being adjacent to each other and driving both of the pair of transmission gears.

Abstract: According to an embodiment of the present invention, color drift is prevented from occurring in a color image by detecting a position of a rotation informing mechanism integrally held by one of first, second, and third gears to detect a phase change in full rotation of at least one gear, detecting a position of a rotation informing mechanism integrally held by a fourth gear to detect a phase in full rotation, and setting, on the basis of the detected one phase change and the detected other phase change, phases during start of rotation of the respective gears such that a phase of a fourth image held by an image holding member rotated by the fourth gear coincides with phases of first to third images held by respective image holding members rotated by the first, second, and third gears.

Abstract: An image forming apparatus comprising: an image carrier to carry a toner image; a driving unit to drive the image carrier to rotate; a transfer unit to transfer the toner image at a transfer position; a cleaner at a cleaning position to remove toner remaining on the image carrier after transfer; an obtaining unit to obtain information indicating a likelihood of the remaining toner adhering to the image carrier; a judging unit to judge whether or not the likelihood is equal to or lower than a predetermined value; and a controller to control the driving unit (i) to stop driving the image carrier before a rear end of an area of the image carrier on which the toner remains reaches the cleaning position, when the judging unit judges affirmatively, and, (ii) to stop driving the image carrier after the cleaner removes the remaining toner, when the judging unit judges negatively.

Abstract: A driving device includes a motor, and first and second gears having gear teeth engaged with each other. At least one of the first gear and the second gear includes a crowning portion formed at a tooth surface of each of the gear teeth such that the center of the tooth surface is more convex than both ends of the tooth surface in a tooth width direction. A height of the crowning portion is determined to effectively compensate for misalignment between the first gear and the second gear.

Abstract: An image forming apparatus that enables a high-quality color image having less image deterioration can be formed. First and second developing units develop an electrostatic latent image formed on each of first and second rotating members. First and second drive units drive the respective first and second rotating members. A control unit controls the first and second drive units in order that a phase of the first rotating member and a phase of the second rotating member have a predetermined relationship therebetween after the completion of an image formation, performs a stop process for stopping the first and second drive units, and further varies a period from the completion of controlling the drives of the first and second drive units to the execution of the stop process.

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: A rotary member apparatus includes a main drive unit configured to apply a driving torque to a photosensitive drum through a drive transfer unit, a torque limiter configured to limit the driving torque transmitted from the main drive unit to the photosensitive drum, a compensation drive unit configured to apply a torque for adjusting an angular velocity of the photosensitive drum, an encoder configured to detect the angular velocity of the photosensitive drum, and a compensation drive controller configured to control the torque applied by the compensation drive unit on the basis of a detection result obtained by the encoder.

Abstract: A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes a photosensitive drum, and a developing roller for developing a latent image. A development coupling portion is provided that includes a driven portion. The development coupling portion also includes an intermediary portion configured and positioned to engage with the driven portion, and to be movable relative to the driven portion while maintaining engagement with the driven portion. The development coupling portion still further includes a driving portion configured and positioned to engage with the intermediary portion, and to be movable relative to the intermediary portion in a direction crossing the axis of the developing roller while maintaining engagement with the intermediary portion.

Abstract: An image forming apparatus capable of achieving improved image quality even when image formation is performed using a plurality of types of drive sources different in characteristics. Image forming units for colors form toner images of the respective colors on respective photosensitive drums each of which is driven by a DC motor for rotation. Encoder sensors detect information on the rotational speed of the photosensitive drums. An image forming unit for black forms a black toner image on a photosensitive drum having an outer diameter larger than that of the photosensitive drums for colors, which is driven by a stepper motor for rotation. An intermediate transfer belt transfers toner images formed on the respective photosensitive drums to a sheet. A motor controller controls a drive frequency of the stepper motor based on information on the rotational speed of the photosensitive drum for black.

Abstract: The image forming apparatus is capable of preventing operation noise of a drive part from increasing in performing phase adjustment of an image bearing member, reducing consumption power, or achieving a reduction in motor specifications. Based on a rotation phase of a photosensitive drum (1K) detected by a phase detection sensor and a rotation phase of another photosensitive drum detected by a phase detection sensor, a CPU performs the phase adjustment by reducing a rotation speed of a motor (C) that is driving the another photosensitive drum so as to achieve a predetermined phase relationship, and causes an image forming unit to form an image after the phase adjustment is finished.

Abstract: A motor assembly to minimize deformation of a vibration-proof member and to achieve stable motor mounting configuration, as well as an image forming apparatus employing the motor assembly, are disclosed. The motor assembly includes a motor, a fixing member to which the motor is fixed, a vibration-proof member provided between the motor and the fixing member to prevent vibration of the motor from being transmitted to the fixing member, and a reinforcing piece having a predetermined strength to prevent relative movement between the motor and the fixing member.

Abstract: There is provided an image forming apparatus that includes couplings for photoreceptor drums, couplings for waste toner transporting screws, and couplings for developing rollers, that transmit driving force to each of a plurality of driving shafts for driving a process portion that performs image formation by an electrophotographic method, and a plurality of coupling attaching/detaching members for attaching/detaching the plurality of coupling members, so as to drive the process portion. In the image forming apparatus, the plurality of coupling attaching/detaching members are provided so as to be movable independently, and the image forming apparatus includes a coupling attaching/detaching member driving mechanism that operates the coupling attaching/detaching members in association with each other.