Abstract: An image forming apparatus includes a housing; a driving portion provided in the housing and configured to generate a driving force; an interchangeable member interchangeably provided in the housing and having a driving-force-receiving portion at which the driving force is received, the interchangeable member being configured to rotate by receiving the driving force at the driving-force-receiving portion; a driving-force-transmitting portion provided in the housing and connecting the driving portion and the interchangeable member to each other, the driving-force-transmitting portion being configured to transmit the driving force from the driving portion to the interchangeable member; and a connecting-and-disconnecting mechanism that allows the driving force to be transmitted between the driving portion and the driving-force-transmitting portion when the interchangeable member rotates, and prevents the driving force from being transmitted between the driving portion and the driving-force-transmitting portion w

Abstract: An image forming apparatus includes a casing having a frame, a drive source configured to generate a driving force, a gear mechanism configured to receive the driving force of the drive source, and a drive source support formed in the frame. The drive source support encloses and supports the drive source. At least an upper portion of the drive source support has a plurality of first openings which are spaced from each other.

Abstract: An electric motor system includes a brushless direct-current motor, a driver circuit, a position sensor, and a control circuit. The motor has an output shaft for transmitting torque. The driver circuit supplies power to the motor according to a control signal input thereto. The position sensor measures an angular, rotational position of the motor shaft. The control circuit controls operation of the motor. The control circuit includes a position sensor terminal, a reference terminal, a differential calculator, a controller, and a gain adjuster. The position sensor terminal receives a feedback signal. The reference terminal receives a reference signal. The differential calculator generates an error signal representing a difference between the measured and targeted rotational positions. The controller generates the control signal based on the error signal through a combination of control actions. The gain adjuster is connected to the controller to adjust a gain of each control action.

Abstract: An image forming apparatus includes image bearing members that bear formed images; a driving source that rotationally drives the image bearing members and whose rotational direction is switchable between a first direction and a second direction; a first driving-force transmitting unit that transmits a rotational driving force of the driving source rotationally driven in the first direction as a unidirectional rotational driving force to the image bearing members; and a second driving-force transmitting unit that transmits a rotational driving force of the driving source rotationally driven in the second direction as a unidirectional rotational driving force to one or more of the image bearing members and does not transmit the rotational driving force to a remaining one or more of the image bearing members. The first and second driving-force transmitting units are switched therebetween by changing the rotational direction of the driving source.

Abstract: An electrophotographic photoreceptor is removably installed and used in a device main unit of an electrophotography application device so as to form a process cartridge. The device main unit includes a driving-side power transmission portion. The photoreceptor includes a photosensitive drum including a cylindrical conductive base having a photosensitive layer containing a photoconductive material. A flange is fitted to the photosensitive drum. The flange includes a driven-side driving force transmission portion that has a cylindrical member and engaging protrusions. The flange transmits to the photosensitive drum a rotational driving force from the driving-side power transmission portion. A center of the cylindrical member is disposed on a central axis of the photosensitive drum. The protrusions are parallel to the central axis at positions on the outer periphery of the cylindrical member that trisect the cylindrical member.

Abstract: A drive switching device includes a driving source and a switching unit. The driving source is rotationally driven in one direction. The switching unit is linked with the driving source such that a driving force therefrom is intermittently transmittable to the switching unit, and switches a transmission direction of the driving force from the driving source between a first direction and a second direction every time the switching unit is linked with the driving source.

Abstract: In a process cartridge detachably mountable to a main assembly of the apparatus and including a photosensitive member and a charging roller, a spacer member for spacing the charging roller from the photosensitive member during the transportation and the displaying is recessed relative to the photosensitive member. The spacer member receives a driving force from the main assembly of the apparatus, by which the spacer member is disengaged to contact the charging roller to the photosensitive member.

Abstract: A plurality of first viscoelastic bodies are disposed in insertion holes of a first rotary member. A plurality of second viscoelastic bodies are disposed in guide holes of a second rotary member. Each of the first and the second viscoelastic bodies has an elastic coefficient changing in accordance with aging due to use. A guide member moves a contact member along the insertion hole and the guide hole. The contact member applies a compressive load to the first viscoelastic body. The aging of the second viscoelastic body due to the compressive load applied thereto moves a position of the first viscoelastic body where the compressive load is received from the contact member toward a farther side from a rotational shaft side.

Abstract: An image forming apparatus has a housing. Inside the housing, there are provided an image carrying member, a developing unit, a driving force transmission unit, a contact/separation mechanism, a transmission enable/disable mechanism, a cover movably supported by the housing, and a single link member configured to move in association with an opening/closing movement of the cover. When the link member moves in association with the opening movement of the cover, the contact/separation mechanism moves the developing unit to a detachable position, and the transmission enable/disable mechanism moves the driving force transmission unit to the transmission cutoff position.

Abstract: The present invention relates to a rotational force driving assembly and a process cartridge used for being engaged with a rotational force driving head inside an electrophotographic image forming device so as to transmit rotary driving force, comprising a photosensitive member hub, a rotational force receiving component, a side plate, and an axis offset adjusting mechanism of the rotational force receiving component, wherein the axis offset adjusting mechanism can slide relative to the side plate; the axis offset adjusting mechanism of the rotational force receiving component is connected with the rotational force receiving component; when the rotational force driving assembly is not installed into the electrophotographic image forming device, and thus is not subjected to external force, the axis offset adjusting mechanism enables the axis of the rotational force receiving component to make parallel offset relative to the axis of the photosensitive member hub; and after the electrophotographic image forming

Abstract: An image forming apparatus includes a driving portion configured to generate a driving force, a first magnet configured to rotate when receiving the driving force from the driving portion, a second magnet that faces the first magnet with a gap interposed therebetween and is configured to rotate together with the first magnet while attracting and being attracted by the first magnet with magnetism, a rotating member configured to rotate in a predetermined direction when receiving the driving force from the second magnet, and a backward-rotation-suppressing mechanism configured to suppress rotation of the rotating member in a direction opposite to the predetermined direction.

Abstract: A rotating mechanism driving apparatus is disclosed that includes a frictional transmission configured to output torque via a viscous fluid, the torque being input from the motor; an input shaft rotational amount detecting part configured to detect a rotational amount of an input shaft of the frictional transmission; an output shaft rotational amount detecting part configured to detect a rotational amount of an output shaft of the frictional transmission; an input torque detecting part configured to detect input torque of the frictional transmission; a slip amount calculating part configured to calculate a slip amount between the input shaft and the output shaft; and abnormal state determining part configured to determine abnormal state of a rotating mechanism connected to the output shaft of the frictional transmission based on the input torque and to determine an abnormal state of the frictional transmission based on the slip amount.

Abstract: A mounting system for an encoder is disclosed. The mounting system prevents rotation about the encoder shaft's axis of rotation. The mounting system allows translation in a plane perpendicular to the encoder shaft's axis of rotation.

Abstract: A multi-pass type image forming apparatus allows driving-couplings to couple with and separate from an image-carrier and developing units simultaneously. The apparatus includes a main body, a cover to open or close the main body, an image-carrier unit including an image-carrier and first driven-coupling connected to the image-carrier, developing units including a developing roller and a second driven-coupling connected to the developing roller, first and second driving-couplings to transmit drive power to the first and second driven-couplings, a link unit to move in a first direction in linkage with opening/closing operations of the cover, and a guide unit to be rotatable about the first driving-coupling in linkage with the link unit, the guide unit being moved when rotated about the first driving-coupling so as to couple or separate the first and second driving-couplings to or from the first and second driven-couplings.

Abstract: An image forming apparatus is provided. The image forming apparatus may mechanically synchronize eccentricity and run-out deviation for each photosensitive drum of an image forming apparatus that does not individually drive the photosensitive drums. The image forming apparatus includes photosensitive drums in which electrostatic latent images are formed, a single motor configured to rotate the photosensitive drums, driving gears configured to transmit a rotating force of the single motor to the plurality of photosensitive drums, and couplers interposed between the photosensitive drums and the driving gears and configured to enable the photosensitive drums and the driving gears to be synchronized with each other in such a manner that any one of the photosensitive drums and the driving gears follows a phase of the other one thereof when the photosensitive drums are coupled to the driving gears.

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: An image formation unit includes a first unit rotatably supporting an image carrier on which an electrostatic latent image is to be formed, and a second unit rotatably supporting a developer carrier configured to develop the electrostatic latent image with a developer. The first unit includes a first engagement portion formed at one end in the direction of the rotational axis of the image carrier, and a second engagement portion provided at a predetermined distance from the first engagement portion at the one end side. The second unit includes a first engaged portion engaged with the first engagement portion, a second engaged portion engaged with the second engagement portion, and a drive input portion provided between the first and second engaged portions and configured to rotate the developer carrier.

Abstract: A drive unit includes a drive pulley connected to a drive source, a driven pulley connected to a target to be moved, at least one relay pulley for transmitting power from the drive pulley to the driven pulley, a plurality of belts including a first belt entrained around the drive pulley and the relay pulley, and a second belt entrained around the relay pulley and the driven pulley, a first tension application device, and a second tension application device. The first tension application device contacts the first belt to provide tension thereto. The second tension application device contacts the second belt to provide tension thereto. A cyclic speed variation component of the first belt in one rotation period transmitted to the driven pulley via the relay pulley and a speed variation component of the second belt in one rotation period transmitted to the driven pulley counteract each other.

Abstract: A transmission device for a photosensitive drum includes a sleeve having at least one guiding groove, a transmission unit having a shaft disposed in the sleeve and capable of moving and rotating at the same time, an elastic member, and a gear member receiving the sleeve and the elastic member so that the elastic member exerts elastic force on the shaft of the transmission unit. The transmission unit has two engagement blocks and a receiving space between them. Each engagement block has an inclined outer surface, an inner surface, an inclined top surface and an engagement concave connecting the inner and outer surfaces. The engagement concaves are opened toward opposite directions for engagement with two pillars of a drive member of an electronic image forming apparatus respectively. As a result, the transmission device can be connected with and separated from the drive member smoothly.

Abstract: A transmission device for a photosensitive drum includes a sleeve, a transmission unit disposed in the sleeve and capable of moving and rotating at the same time, an elastic member, and a shell receiving the sleeve and the elastic member so that a relatively larger radius section and a relatively smaller radius section of the elastic member exert elastic force on the sleeve and the transmission unit, respectively. The transmission unit has two engagement blocks and a receiving space between them. Each engagement block has an inclined outer surface, an inner surface, an inclined top surface and an engagement concave connecting the inner and outer surfaces. The engagement concaves are opened toward opposite directions for engagement with two pillars of a drive member of an electronic image forming apparatus respectively. As a result, the transmission device can be connected with and separated from the drive member smoothly.

Abstract: A transmission device for a photosensitive drum includes a sleeve having at least one guiding groove, a transmission unit having a shaft disposed in the sleeve and capable of moving and rotating at the same time, an elastic member, and a gear member receiving the sleeve and the elastic member so that the elastic member exerts elastic force on the shaft of the transmission unit. The transmission unit has two L-shaped engagement blocks defining a receiving space therebetween. Each L-shaped engagement block has an inclined outer surface, an inner surface, an inclined top surface and an engagement concave connecting the inner and outer surfaces are is rotatably secured to a base. The engagement concaves are opened toward opposite directions for engagement with two pillars of a drive member of an electronic image forming apparatus. Accordingly, the transmission device can be connected with and separated from the drive member smoothly.

Abstract: A rotation shaft coupling structure includes a roller drive shaft including a recessed portion having an internal thread; a rotation roller including a coupling member housing the recessed portion of the roller drive shaft; and a coupling shaft extending through the rotation roller in the axial direction. The coupling shaft includes a threaded portion at a first end portion thereof, the threaded portion mating with the internal thread of the recessed portion, and the coupling shaft couples the roller drive shaft and the rotation roller to each other. The first end portion of the coupling shaft in the axial direction is joined to the roller drive shaft and the rotation roller in the coupling member of the rotation roller, and a second end portion of the coupling shaft in the axial direction is a free end that allows the coupling shaft to extend and contract in the axial direction.

Abstract: A driving device includes an endless metal belt having a strip shape, rotational members, and a polisher. The rotational members bear the metal belt to allow the metal belt to run circularly.

Abstract: A developing device including a developer bearing member rotatable while bearing developer on a surface thereof, a rotary body having a rotary shaft, a casing that contains the developer supplied to the surface of the developer bearing member to accommodate at least a portion of the rotary body, a rotary gear having a rotary shaft parallel to the rotary shaft of the rotary body and disposed outside a lateral wall of the casing to support an end of the rotary shaft of the rotary body, and a stationary shaft member fixed to the lateral wall of the casing to rotatably support the rotary gear. An axial center of the stationary shaft member is collinear with an axial center of the rotary shaft of the rotary body.

Abstract: A rotating part for an image forming apparatus includes a drive member for transmitting power; and a driven member that is rotated by the drive member. The drive member has a male part formed in a direction of a rotation axis, and the driven member has a female part that is formed in the direction of the rotation axis and into which the male part is inserted. The male part is a hexagonal male part whose cross section perpendicular to the rotation axis assumes a hexagonal shape. The female part is a twisted triangular female part that assumes a triangular cross sectional profile in a direction perpendicular to the rotation axis, and a triangle which forms a cross section of a base and a cross section of a top is twisted at a predetermined angle with respect to the rotation axis.

Abstract: A torque receiving assembly, a photosensitive drum and a process cartridge having such torque receiving assembly. The torque receiving assembly having a body having an axis and having an accommodating chamber; a driven shaft disposed coaxially with the body, the driven shaft including a guide stem and a coupling head provided at one axial end of the guide stem, the guide stem having a pair of output arms which extend outwardly in a radial direction, the coupling head having a plurality of projections; wherein a pair of input arms are provided at an inner wall of the accommodating chamber and configured for abutting with the output arms; the guide stem is movable in the axial direction relative to the body, the torque receiving assembly further comprises a distance-limiting mechanism that defines a maximum distance the driven shaft is able to move relative to the body in the axis direction.

Abstract: In an image forming apparatus, a rotating body has a follower member that is arranged to confront a drive member in an axial direction of the drive member. A drive transmitting member transmits drive force from the drive member to the follower member by coupling the drive member and the follower member with each other, while allowing relative positional deviation between the drive member and the follower member on a plane perpendicular to the axial direction of the drive member within a prescribed range. The drive member and the follower member have a drive-member side contact part and a follower-member side contact part, respectively. A making-contact member brings the drive-member side contact part and the follower-member side contact part into contact with each other.

Abstract: An image forming apparatus includes a main body, a cover to open and close a front of the main body, a tray slidably mounted in the main body through the front of the main body, at least one developing cartridge mounted in the main body in a state in which the developing cartridge is received in the tray, at least one driving coupler member provided at one side of the main body to drive the developing cartridge mounted in the main body, a link member operating simultaneously with opening and closing of the cover to move in a first direction, and a guide member to support the at least one driving coupler member, the guide member operating simultaneously with the link member to move in a second direction perpendicular to the first direction, wherein the guide member is pressed by the link member, when the cover opens the main body, to separate the driving coupler member from the developing cartridge.

Abstract: A method for aligning a photoconductor cartridge (200) in an electrophotographic device includes providing at least two holes in a first end of the cartridge. At least two pins (251) are provided in a frame of the electrophotographic device which mate with the holes in the first end of the cartridge when the cartridge is inserted in the electrophotographic device. A drive mechanism contacts a spherical bearing of a photoconductor of the cartridge and drives a pair of drive dogs. One drive dog is affixed to a spline on the drive mechanism and a second drive dog is affixed to the spherical bearing. At least one hole is provided in a second end of the cartridge. At least one pin is provided in a frame of the electrophotographic device which mate with the hole in the second end of the cartridge when the cartridge is inserted in the electrophotographic device.

Abstract: A gear transmission device includes a first external gear driven by a drive motor attached to a first side of a frame and a first internal gear driven by the first external gear. The first internal gear includes an outer cylinder portion, an end plate, an annular opening, and an inner cylinder portion including a shaft hole,. The outer cylinder portion includes internal teeth formed on an inner circumferential surface thereof. The inner cylinder portion is formed concentrically inside the outer cylinder portion. The end plate connects the outer cylinder portion, the inner cylinder portion, and the shaft hole at one end in an axial direction. In a state in which the annular opening faces a second side of the frame opposite the first side thereof, the first external gear is inserted to the annular opening to mesh with the internal teeth of the outer cylinder portion.

Abstract: For example, the present invention relates to a vibration type driving apparatus which includes: a vibrating body that includes an elastic body provided with a vibrating portion, and an electrical-mechanical energy converting element fixed to the elastic body; and a driven body in pressure contact with a frictional portion of the vibrating portion, wherein the vibrating body and the driven body are relatively moved by driving vibration generated when an alternating voltage is applied to the electrical-mechanical energy converting element; the elastic body includes a fixing portion for fixing the vibrating body to another member, and a connecting portion for connecting the vibrating portion and the fixing portion; and the connecting portion includes plural uneven rigidity components in a circumferential direction.

Abstract: An image scanning device has a sheet conveying roller conveying a sheet when a conveyed sheet scanning function is activated, a guide member defining a sheet feed path, a first gear transmitting a driving force to the sheet conveying roller, a first supporting shaft extending in a direction parallel with a width direction of the sheet feed path and supporting the first gear, a second gear engaging with the first gear, a second supporting shaft extending in a direction perpendicular to the first supporting shaft and supporting the second gear, a holder unit holding the second supporting shaft, the holder unit arranged at one end of the sheet feed path in the width direction, a reinforce member made of metal and extending in the width direction, first and second fixing units fixing longitudinal ends of the reinforce member to the holder unit and the guide member, respectively.

Abstract: A developing cartridge mountable to a development rotary of an electrophotographic image forming apparatus, a coupling member for transmitting a rotational force from a main assembly engaging portion to a developing roller, the coupling member being engageable and disengageable relative to the engaging portion with rotation of the rotary, the coupling member being movable among a rotational force transmitting angular position, a pre-engagement angular position in which the coupling member is inclined relative to that in the transmitting angular position to engage with the engaging portion, and a disengaging angular position for disengaging therefrom; and an inclination regulating member movable between a regulating position for positioning the coupling member to the pre-engagement position and a retracted position, the inclination regulating member being movable from the retracted position to the regulating position by being abutted by a function member of the rotary.

Abstract: A damper device having: an input member into which a rotary drive force is inputted; a passive member which receives the rotary drive force inputted into the input member and rotates; a viscoelastic material which is provided between the input member and the passive member; and a flexible member which prevents displacement of the viscoelastic material in a diametrical direction while not preventing a shake of the viscoelastic material in a rotating direction.

Abstract: A transmission mechanism has an input gear, a first intermediate gear configured to engage with the input gear. A rotation shaft of the first intermediate gear is movable between a first position and a second position along an elongated hole formed on a supporting member. A first output gear is configured to engage with the first intermediate gear when the rotation shaft is located at the first position, and a second output gear configured to engage with the first intermediate gear when the rotation shaft is located at the second position. The rotation shaft can be located at a third position which is an intermediate position between the first position and the second position, the first intermediate gear engaging with both the first output gear and the second output gear when the rotation shaft is located at the third position.

Abstract: Provided is a driving force transmission device including a sun gear that rotates by receiving a driving force from a driving source, an internal gear that is arranged coaxially with the sun gear, a planetary gear that engages with the sun gear and the internal gear, a rotary member that is provided coaxially with the sun gear and the internal gear and installed with the planetary gear so as to rotate corresponding to revolution of the planetary gear, and an urging member that urges the planetary gear toward the rotary member.

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: Detection precision is improved by reducing a detection error of a change in position of a target. A correction value derivation apparatus is provided for deriving a correction value used in correction of a displacement amount derived based on an encoder signal indicating a change in position of a movable portion as a target. A displacement amount derivation unit is configured to derive a detected displacement amount of the movable portion based on the encoder signal. A displacement velocity derivation unit is configured to derive a detected displacement velocity based on the detected displacement amount derived by the displacement amount derivation unit. An average displacement velocity calculation unit is configured to calculate an average displacement velocity over a predetermined displacement range. A correction value derivation unit is configured to derive the correction value based on the detected displacement velocity and the average displacement velocity.

Abstract: A toner drum gear flange socket adapted for engagement with a force transmitting end of a drive shaft in an electrophotographic image forming apparatus. The socket includes a bottom wall and an outer cylindrical wall including an inner surface and defining a central axis. Circumferentially spaced apart curved base wall portions extend axially from the bottom wall. Each base wall portion includes an enlarged end portion that defines a radially inwardly extending projection. A leg wall portion extends radially from one end of each curved base wall portion. Each leg wall portion defines an elongated contact surface. The radially inwardly extending projections secure the force transmitting end of the drive shaft within the socket, and the elongated contact surfaces receive driving rotational force from the force transmitting end of the drive shaft.

Abstract: A drive transmission device that transmits rotation from a drive source of an image forming apparatus to a rotary body detachably attachable relative to a main body thereof in an axial direction includes two external gears, a cylindrical member, and an intermediate-body retainer. The two external gears include teeth on an outer circumferential surface thereof extending in an axial direction. The cylindrical member includes an internal gear formed on an inner circumferential surface thereof to mesh with the external gears, and a flange on a portion of an outer circumferential surface of the cylindrical member, the flange including a projection. The intermediate-body retainer includes a depression to fit with the projection of the flange to prevent the cylindrical member from getting disengaged from the external gears. The external gears constitute a two-stage spline joint that meshes with the internal gear of the cylindrical member.

Abstract: A drive unit for rotating a first rotary member and a second rotary member disposed around the first rotary member includes a drive source, an output gear driven by the drive source, a first gear greater in diameter than the output gear and configured to engage the output gear, a first joint member projecting from the first gear coaxially and coupled to the first rotary member, a second gear smaller in diameter than the first gear and connected between the first gear and the first joint member, a driven gear smaller in diameter than the first gear and disposed within an area of the first gear in a radial direction thereof to engage the second gear to be driven thereby, and a second joint member projecting from the driven gear coaxially and connected to the second rotary member.

Abstract: A drive unit includes a drive pulley connected to a drive source, a driven pulley connected to a target to be moved, at least one relay pulley for transmitting power from the drive pulley to the driven pulley, a plurality of belts including a first belt entrained around the drive pulley and the relay pulley, and a second belt entrained around the relay pulley and the driven pulley, a first tension application device, and a second tension application device. The first tension application device contacts the first belt to provide tension thereto. The second tension application device contacts the second belt to provide tension thereto. A cyclic speed variation component of the first belt in one rotation period transmitted to the driven pulley via the relay pulley and a speed variation component of the second belt in one rotation period transmitted to the driven pulley counteract each other.

Abstract: A drive transmitter, including a first rotational axis transmitting a drive force of a drive source to a first rotator, a second rotational axis transmitting a drive force of the drive source to a second rotator, and an idler gear configured to transmit a drive force to the second rotational axis; wherein the first rotational axis penetrates the idler gear with a gap therebetween.

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: 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 photosensitive drum assembly and a process cartridge and a process cartridge having an improved structure in which a protrusion for receiving a driving force transmitted from a main body of an image forming apparatus may not be easily worn or damaged. The photosensitive drum assembly that is capable of being combined with a driving shaft including a twisted hole with a non-circular cross-section having a plurality of corners, includes: a support disposed at one side of the photosensitive drum; and an insertion body disposed at one side of the support and including a plurality of protrusions that are capable of being inserted in the twisted hole, wherein at least portions of each of the plurality of protrusions based on a cross-section of each protrusion that is perpendicular to the driving shaft, closely contacts two side surfaces of the twisted hole that constitute one of the plurality of corners of the twisted hole, respectively.

Abstract: A gear transmission device includes a first external gear driven by a drive motor attached to a first side of a frame and a first internal gear driven by the first external gear. The first internal gear includes an outer cylinder portion, an end plate, an annular opening, and an inner cylinder portion including a shaft hole. The outer cylinder portion includes internal teeth formed on an inner circumferential surface thereof. The inner cylinder portion is formed concentrically inside the outer cylinder portion. The end plate connects the outer cylinder portion, the inner cylinder portion, and the shaft hole at one end in an axial direction. In a state in which the annular opening faces a second side of the frame opposite the first side thereof, the first external gear is inserted to the annular opening to mesh with the internal teeth of the outer cylinder portion.

Abstract: A cartridge drive gear assembly for holding a drum coupling includes a drive gear having an outer surface and an inner surface, the inner surface including inner projections which extend into the interior of the drive gear and includes at least two voids disposed on opposing sides of the inner projections, and at least one slot disposed in the inner surface.

Abstract: An image forming apparatus includes: a body frame accommodating an image forming unit; and a support frame supporting an image reading unit and disposed to confront the body frame in a confronting direction, the support frame having a first end portion and a second end portion opposite to each other in a first direction perpendicular to the confronting direction. The support frame includes: first and second engaging portions provided at the first and second end portions respectively; and a pair of grip portions. The body frame has a first edge portion and a second edge portion opposite to each other in the first direction, the body frame including: a first engaged portion provided at the first edge portion and engageable with the first engaging portion; and a second engaged portion provided at the second edge portion and engageable with the second engaging portion.

Abstract: The invention relates to a photosensitive drum driving head, which comprises drum flange, drum shaft and boss, wherein the drum flange is disposed on the end portion of a photosensitive drum and connected with the photosensitive drum; the drum shaft is axially extended from the end portion of the drum flange; the boss is axially extended from the end face of the drum shaft and engaged with a recess in a driving head of image forming apparatus; three vertical convex teeth radially extended along the boss and engaged with power transmission portions are formed on side wall of the boss, perpendicular to the drum shaft, extended along an axial line of the photosensitive drum, and provided with mating surfaces formed by longitudinal cutting angles on end faces of the vertical convex teeth; at least one mating surface is engaged with an edge of a twisted bevel of the recess.