JP2013061403A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slide member between a drive force transmitting member and an urging member to allow smooth sliding of the drive force transmitting member and the urging member, and thereby solving problems of an increase in wear, noise, heat generation, and drive load.SOLUTION: An image forming apparatus includes: a pressure member that is provided between a drive force transmitting member and an urging member, and transmits an urging force from the urging member to the drive force transmitting member; and a regulation unit that regulates, when the drive force transmitting member is connected with a drive force receiving part and rotates, a movement of the pressure member at a position where the pressure member does not contact the drive force transmitting member.

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium.

  2. Description of the Related Art In recent years, in an image forming apparatus that forms an image on a recording medium, an opportunity for replacement by a service person or a user himself / herself is increasing as a product has a longer service life. Of these, if the replacement part is in a deep position in the main unit, if the replacement work is complicated, or if there are multiple replacement parts, the replacement part can be included in a replaceable unit and easily removed. There is a growing need for new units. As an example of a unit exchanged by a service person or a user, there is a process cartridge in which an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrated into a cartridge. Another example is an intermediate transfer unit used in a color electrophotographic image forming apparatus. By unitizing components that are frequently exchanged in this way, the user can perform maintenance of the apparatus by himself / herself without depending on the service person, so that the operability can be remarkably improved. For this reason, the cartridge system and the intermediate transfer body unit system are widely used in image forming apparatuses.

  Since the process cartridge and the intermediate transfer body unit as described above have a drive unit that receives a drive from the drive source of the main body and transports the paper and the like when mounted on the main body of the image forming apparatus, Devises to cancel are made.

  Patent Document 1 introduces a technique for ensuring connection and release of driving in an image forming apparatus having a mechanism for transmitting and releasing driving in conjunction with opening and closing of a process cartridge attaching / detaching door as described above. Yes.

  Further, the detachable units as described above can be roughly divided into two types depending on the difference in the mounting / demounting direction of the cartridge. One is for attaching and detaching the unit in a direction parallel to the sheet conveying direction in the apparatus, and the other is for attaching and detaching the unit in a direction orthogonal to the sheet conveying direction in the apparatus.

JP 2000-338842 A

  The image forming apparatus described in Patent Document 1 is an electrophotographic image forming apparatus in which a detachable unit is detachable in a direction parallel to a sheet conveying direction in the apparatus, and is driven by a drum in conjunction with opening and closing of a cover. A configuration in which the gears are connected and released is described.

  In the conventional process cartridge mounting / dismounting configuration, a unit for connecting and disconnecting the drive is advanced and retracted in the axial direction of the joint so that the unit can be mounted / dismounted.

  However, in the drive connection and release mechanism in the image forming apparatus described in Patent Document 1, the drum drive gear having a joint portion that performs drum drive always receives a pressing force from the pressing member, and receives the pressing force even in the drive connection state. The drum is driven as it is. For this reason, the drum drive gear may suffer from problems such as wear, noise, heat generation, and increased drive load due to sliding with the pressing member.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a drive device that solves the above-described problems and does not impair the convenience of drive connection and drive release, which are originally intended in the background art.

In order to solve the above problems, a typical configuration of the present invention is an image forming apparatus in which a unit is detachable.
When the unit is mounted on the apparatus main body of the image forming apparatus, a connection position for connecting a driving force receiving portion provided in the unit for transmitting a driving force to the unit, and the driving force receiving portion A driving force transmission member that takes a separated position and is configured to generate a force in a direction approaching the driving force receiving portion in the axial direction when rotating in conjunction with the driving force receiving portion. A driving force transmission member;
A biasing member that biases the driving force transmission member in a direction in which the driving force transmission member moves from the separated position to the coupling position;
A pressure member provided between the driving force transmission member and the biasing member, the pressure member transmitting a biasing force from the biasing member to the driving force transmission member;
When the driving force transmission member rotates in connection with the driving force receiving portion, a regulating portion that restricts the movement of the pressing member at a position where the pressing member does not contact the driving force transmission member;
It is characterized by having.

  In the present invention, by providing a sliding member between the driving force transmission member and the urging member, the sliding between the driving force transmission member and the urging member is made smooth, and wear, noise, heat generation, and driving load are reduced. It becomes possible to solve the increase problem.

Explanatory drawing showing an image forming apparatus (A) A cross-sectional view schematically showing the cartridge mounting operation in the first embodiment, (b) a state in which the cartridge is mounted and the cartridge replacement opening / closing cover is not closed in the first embodiment. (C) In the first embodiment, the cartridge replacement opening / closing cover is closed and the drive input from the main body drive source is not performed in the first embodiment. FIG. 4D is a cross-sectional view schematically showing a state in which the driving device is being driven in the first embodiment. (A) A cross-sectional view schematically showing the mounting operation of the cartridge in the second embodiment, (b) schematically showing a state in which the cartridge is mounted and the couplings are not fitted in the second embodiment. (C) Cross-sectional view schematically showing a state in which the cartridge is mounted, the couplings are fitted to each other, and the drive input from the main body drive source is not performed in the second embodiment. (D) Sectional drawing which showed typically the state in which the drive device is driving in 2nd Example. (A) A schematic view of the coupling between the driven coupling and the input side coupling as viewed from the direction orthogonal to the axis, (b) a perspective view showing the positional relationship between the driven coupling and the input side coupling before coupling, (C) is a perspective view of the input side coupling, (d) is a cross-sectional view in the KK direction in FIG. 4 (a), (e) is a perspective view schematically showing the coupled coupling portion, f) is a schematic diagram in which a cylindrical surface through which a broken line M passes is developed into a plane. (A) Perspective view of the entire apparatus with the cartridge replacement opening / closing cover open, (b) Exploded view of parts on the photosensitive drum shaft of the drive unit for driving the cartridge, (c) Door opened The perspective view which shows the positional relationship of the latching member in a state, a bearing, and a coupling cancellation | release link bar, (d) The positional relationship of a latching member, a bearing, and a coupling cancellation | release link bar in the state where the replacement cover is open FIG. 5 is a diagram viewed from the front side of the image forming apparatus, (e) a perspective view showing the positional relationship between the locking member, the bearing and the coupling release link bar when the door is closed, and (f) the replacement cover is closed. FIG. 6 is a diagram viewed from the front side of the image forming apparatus schematically showing the positional relationship between the locking member, the bearing, and the coupling release link bar in a state of being caught. (A) The figure which mounts a cartridge in the apparatus main body from the axis of a photosensitive drum, (b) The figure explaining a cartridge

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the first embodiment, an image forming process cartridge is described as a detachable unit using a driving device of an electrophotographic image forming apparatus that is detachable in a direction parallel to the sheet conveying direction.

  In the second embodiment, an image forming process cartridge is described as a detachable unit using a driving device of an electrophotographic image forming apparatus that is detachable in a direction orthogonal to the sheet conveying direction.

That is, the first and second embodiments are configured so as not to cause friction due to an excessive urging force to the drive input gear that performs drive connection and release in the drive device described above.
If the present invention is applied to an image forming apparatus and other exchange units other than those described above as needed, it does not depart from the spirit of the present invention.

  Description will be made with reference to FIGS. 1, 2A to 2D, FIGS. 4A to 4F, and FIGS. 5A to 5F.

Here, the entire configuration of a laser beam printer as an image forming apparatus will be described as an order of description. Next, an image forming process cartridge (hereinafter referred to as cartridge) mounting operation, coupling shape, coupling connection operation, coupling connection release operation, and cartridge removal operation will be described in this order.
In the following description, the right direction in FIG. 1 will be described as the front side of the image forming apparatus, and the left direction will be described as the rear side.

{Image forming apparatus body configuration}
The image forming apparatus 1 according to the present embodiment includes an optical unit 2 including a laser diode (not shown), a polygon mirror 21, a lens (not shown), and a reflection mirror 22, and a laser corresponding to image information obtained from the optical unit 2. Irradiate light. As a result, an electrostatic latent image corresponding to the image information is formed on the photosensitive drum 31 which is a drum-shaped electrophotographic photosensitive member. The latent image is developed by a developing unit configured inside the process cartridge 3.

  The frame of the image forming apparatus 1 maintains rigidity by bridging a plate member (not shown) and a conveyance guide member (not shown) between a left side plate (not shown) and a right side plate (not shown). Be drunk. The sheet S is conveyed from the lower cassettes 5 and 6 along the conveyance guide member.

  Further, as shown in FIG. 1, the image forming apparatus according to the present embodiment includes a manual sheet feeding tray 4 that can stack a predetermined amount of sheets S on one side of the image forming apparatus main body 1 as a sheet feeding apparatus. . In addition, a plurality of feeding cassettes 5 and 6 in which a predetermined amount of sheets S are stacked and stored are provided in the lower part of the image forming apparatus main body 1.

  In addition, friction separating type sheet feeding devices 8 and 9 are provided at the installation sites of the feeding cassettes 5 and 6 for feeding the sheets S, respectively.

  When the sheets S in the feeding cassettes 5 and 6 are fed by the respective sheet feeding devices 8 or 9, they are first fed to the conveying roller pair 26 arranged downstream of the separation unit and further arranged downstream thereof. In this case, the skewed state is corrected.

  Next, based on the image information, the registration roller pair 10 that transports the paper at a timing with the latent image formed on the photosensitive drum 31 that constitutes the image forming unit that is a processing unit, and the photosensitive drum 31. It is sent between the transfer roller 11. A transfer roller 11 as a transfer unit is disposed at the transfer position, and the toner image on the photosensitive drum 31 is transferred to the sheet S by applying a voltage.

  Thereafter, the recording medium P that has received the transfer of the toner image is sent to the fixing means 13 along the conveyance guide 12, and a fixing process for fixing the transferred toner image on the sheet surface is performed. The fixing unit 13 includes a driving roller 14 and a fixing roller 15 having a built-in heater, and fixes the transferred toner image on the sheet S by applying heat and pressure to the passing sheet S.

  The image forming apparatus includes a duplex printing mode for performing duplex printing on the sheet S and a simplex printing mode. In the simplex printing mode, the sheet S after the fixing process is formed by the inner discharge roller pair 16 and the outer discharge roller 17. It is discharged onto a discharge tray 18 outside the machine.

  In the double-sided printing mode, the paper is temporarily stacked and stored on the intermediate tray 24 via the refeed path 20 by the switchback operation of the inner discharge roller pair 16 or the outer discharge roller 17.

  Then, the sheet S stored on the intermediate tray 24 is conveyed again to the conveying roller pair 26 for image formation by the refeed device 25, and thereafter discharged outside the apparatus through the same process as the single-sided printing.

{Cartridge loading operation}
Next, the cartridge mounting operation will be described with reference to FIGS. 2A to 2D are cross-sectional views as viewed from the front side of the apparatus, and the paper during printing is conveyed to the back side in the depth direction in the figure.

  FIG. 2A shows the main body side drive unit during the mounting operation of the cartridge and the cartridge in a non-mounted state. In FIG. 2A, P denotes a process cartridge, which is inserted in the direction of arrow E, which is a direction intersecting the longitudinal direction (axial direction) of the photosensitive drum, by a user's mounting operation. The direction E is a direction parallel to the sheet conveying direction in the image forming apparatus. 42 is a photosensitive drum, 43 is a housing of the cartridge, and 41 is a coupling as a first engaging portion provided at the end in the longitudinal direction of the photosensitive drum. Reference numeral 50 denotes a main body side drive unit. 45 is a drive input gear which is a drive force transmission member, 45a is an input side coupling as a second engagement portion, 45c is a drive input gear tooth surface, 46 is a drive input gear bearing on the side close to the cartridge, Reference numeral 47 denotes a bearing of the drive input gear on the side far from the cartridge. The drive input gear 45 is supported by the two bearings so as to be rotatable and movable in the axial direction. Reference numeral 51 denotes a main body frame metal plate, and reference numeral 55 denotes a metal plate that forms a frame of the drive unit. Reference numeral 52 denotes a pressure plate that contacts the drive input gear in the state shown in FIG. 2A and applies a biasing force to the drive input gear toward the cartridge in the axial direction (in the direction of arrow G in the figure). The coil spring 54 applies a biasing force to the drive input gear via the pressurizing member. 53 is a guide member of the pressure member, and is also a member supporting the other end of the compression coil spring. The guide member 53 is fixed to the frame side plate 55 of the drive unit. The drive input gear 45 receives an urging force from the pressure member at the end portion 45b on the non-cartridge side in the axial direction, and is pressed against the locking member 49 via the abutting surface 45d. The locking member 49 is formed integrally with a cam portion 49a having a twisted guide surface, and is movable in a screw shape. However, in the state shown in FIGS. 2A and 2B, the cam portion 49a abuts against the mating cam surface 46d with a surface perpendicular to the axial direction of the cam portion 49a, and therefore does not move in the axial direction of the drive input gear. For this reason, the drive input gear 45 is held at a position where the cartridge does not interfere with the cartridge inserted in the direction E. When the cartridge is mounted by a user operation, the state shown in FIG. The position of FIG. 2B is the position of FIG. 1 in a side view, and is positioned by a positioning member (not shown) with respect to the product vertical direction, the front-rear direction, and the rotation direction around the photosensitive drum. At this stage, the cartridge side coupling 41 and the coupling on the drive input gear 45 side are not yet coupled.

{Coupling shape}
Next, the shapes of the photosensitive drum 42 side coupling 41 and the drive input gear 45 side coupling 45a will be described with reference to FIGS. FIG. 4A shows a state where the coupling of the driven coupling 41 and the input side coupling 45a is viewed from a direction orthogonal to the axis. 4B is a perspective view showing the positional relationship between the driven coupling 41 and the input side coupling 45a before coupling, and FIG. 4C is a perspective view of the input side coupling 45a. Yes. As shown in FIG. 4B, the driven coupling 41 has a triangular cross section, and has a shape with fillets at three corners of a triangular prism that is spirally twisted in the axial direction. In addition, there is a concave shape 41d for aligning the center position with the counterpart coupling at the center of the shaft. Similarly, the counterpart coupling 45a has a triangular cross section, and has a shape with a fillet in a recess hole spirally twisted in the axial direction. The coupling 45a has a convex shape 45g for aligning the center position with the counterpart coupling at the axial center. The cross section of the concave portion of the input side coupling is a triangle that is larger than the triangle of the cross sectional shape of the driven side triangular prism so that it can be fitted with the counterpart triangular prism shape. FIG. 4D is a cross-sectional view in the KK direction in FIG. 4A and shows the positional relationship between the couplings in a coupled state. As shown in FIG. 4D, in the driving state, the couplings are in contact with each other at three locations (R1 to R3) in the sectional view in the KK direction. When the paper is conveyed, the coupling and the photosensitive drum 42 rotate in the direction indicated by the arrow in FIG. FIG. 4E is a perspective view schematically showing the coupled coupling portion. The coupling used in the present embodiment is formed so that the spiral pitches on the non-driving side and the input side are the same. For this reason, the coupling is performed on a virtual cylindrical surface through which R1 to R3 centering on the rotation axis passes. They come in spiral contact. A broken line M in FIG. 4E shows a spiral contact portion passing through the point R1. FIG. 4F is a schematic diagram in which a cylindrical surface through which a broken line M passes is developed in a plane. Assume that the angle formed by M and the axial direction is θ, and T is the rotational force in the cylindrical surface passing through M around the photosensitive drum 42. Assuming that a rotational force is applied to one point t in FIG. 4F, the force that the input side coupling receives along the line M is T ′, and the force that the driven side coupling receives as a reaction is T ′ is generated in the direction opposite to T ′. For this reason, when driving is performed between the couplings, they move toward each other in the axial direction. When driving in the direction opposite to the paper transport direction is applied, the cup is moved. It operates so that the rings are separated from each other in the axial direction.

{Coupling connection}
Next, coupling is coupled in conjunction with the movement of the cartridge replacement opening / closing cover in this embodiment using FIGS. 2B, 2C and 5A to 5F. The configuration will be described.

  FIG. 5A is a perspective view of the entire apparatus in a state where the cartridge replacement opening / closing cover is open. FIG. 5B is an exploded view of components on the photosensitive drum 42 axis of the drive unit 50 for driving the cartridge. The cartridge is attached and detached in the direction of arrow U in FIG. The cartridge replacement opening / closing cover 57 opens and closes the opening 100 </ b> A in the direction Q in the drawing, and operates the coupling release link bar 58, which is a connecting member connected to the opening / closing cover 57. In FIG. 5A, 50 schematically indicates the position of the drive unit in the apparatus main body 100. FIG. 5C is a perspective view showing a positional relationship among the locking member 49, the bearing 46, and the coupling release link bar 58 in a state where the door is opened. FIG. 5D is a diagram schematically showing the positional relationship among the locking member 49, the bearing 46, and the coupling release link bar 58 in a state where the replacement cover is opened, as viewed from the front side of the image forming apparatus. . FIG. 5E is a perspective view showing the positional relationship among the locking member 49, the bearing 46, and the coupling release link bar 58 when the door is closed. FIG. 5F is a diagram schematically showing the positional relationship among the locking member 49, the bearing 46, and the coupling release link bar 58 with the replacement cover closed, as viewed from the front side of the image forming apparatus. Represents.

  Reference numeral 49 a in FIG. 5B denotes a guided cam portion formed integrally with the locking member 49. Reference numeral 46d denotes a fixed cam portion which is formed integrally with the bearing 46 of the drive input gear and acts on the cam portion 49a formed integrally with the locking member 49. The locking member 49 receives a biasing force in the direction of arrow G through the drive input gear 45 in a state where the cartridge replacement opening / closing cover 57 is open. When the user or service person closes the cartridge replacement opening / closing cover 57 after the cartridge is mounted, the cam member 49a is pushed down by the link bar 58 connected to the opening / closing cover, and rotates by receiving a force in the rotational direction about the axis. When the cartridge replacement opening / closing cover is closed from the open state, the state changes from the state shown in FIG. 5D to the state shown in FIG. 5F. At this time, the locking member 49 moves in the shape of a screw along the cam portion 46d of the mating member while rotating about the shaft center, and moves in the direction of H in each figure in the axial direction. When the locking member 49 moves in the H direction, the drive input gear 45 is pressed in the G direction by the urging member as described above, and therefore moves integrally with the locking member 49 in the H direction.

  In FIG. 2B, the cartridge is mounted, and the cartridge replacement opening / closing cover is open. In this state, the driven side coupling 41a and the input side coupling 45a are still separated from each other. The position of the drive input gear 45 at this time is set as a separated position. When the pressing member 52, the locking member 49, and the drive input gear 45 move in the H direction, the pressing member abutting portion 52b and the regulation unit on the sheet metal side that forms the frame of the corresponding driving unit. The clearance between the butting portions 55b is reduced. Further, the axial clearance between the abutting surface 45d of the drive input gear and the abutting surface 46a provided on the bearing of the drive input gear 45 fixed to the main body frame is also reduced. When the drive input gear 45 and the input side coupling 45a move in the H direction, the input side coupling 45a and the driven side coupling 41a which is a driving force receiving portion are gradually engaged. When the operation of closing the open / close cover is completed, these members move to a position where there is no clearance between the abutting portion 52b of the pressure member and the abutting portion 55b on the sheet metal forming the frame of the drive unit corresponding thereto. Then, the state shown in FIG. At this time, the contact surface between the pressure member and the drive input gear remains in contact, but the locking member 49 is further moved in the H direction in a screw shape, and the locking member 49 and the drive input gear are in a separated state. .

  FIG. 2C shows a state in which the cartridge replacement opening / closing cover is closed after the cartridge is mounted by the user or service person as described above, and at this time, the drive input from the main body drive source is still performed. Absent. At this time, as shown in FIG. 2C, the driven side coupling 41a and the input side coupling 45a are partially engaged. The position of the drive input gear 45 at this time is defined as a coupling position. The abutting surfaces in the axial direction of the driven side coupling 41a and the input side coupling 45a are 41b and 45e, respectively. However, when no driving input is performed, they do not abut and there is a clearance. In the state of FIG. 2 (c), the contact surface of the pressure member and the drive input gear remains in contact, but the pressure member abutment portion 52b is the abutment on the sheet metal side that forms the frame of the drive unit. Since it is received by the portion 55b, the urging force by the urging member 54 is not applied to the drive input gear. Reference numeral 48 denotes a drive upstream gear adjacent to the drive input gear. The gear 48 and the drive input gear 45 are helical gears, and the tooth surface 45c is configured to have a helical angle that receives a force in the direction of an arrow H when driven in the paper transport direction of the main body device. When drive input from the main body drive source is performed from this state, the force in the thrust direction of the drive train helical gear is received and further moved in the H direction, resulting in the state of FIG.

  FIG. 2D shows a state in which the driving device is being driven, and includes a case where the image forming apparatus is performing a printing operation. When the input side coupling is driven, a force is generated in the driven side coupling 41a and the input side coupling 45a in the direction of pulling each other in the axial direction due to the shape of the contact surface. As a result, as shown in FIG. 2 (d), the abutting surfaces 41b and 45e abut against each other, and both rotate integrally. In the driving state, the driving input gear 45 receives the thrust force and abuts the abutting portion 45d and the abutting surface 46a provided on the bearing of the driving input gear. Since the drive input gear has moved further in the H direction from the position of FIG. 2C, the surface 45b on which the drive input gear has been urged by the pressure member and the contact surface 52a of the pressure member are separated. That is, the force in the thrust direction of the helical gear makes the separation between the drive input gear and the pressurizing member more reliable, and the possibility of occurrence of wear, vibration, heat generation, and increase in drive load between them is eliminated. In addition, there is sliding between the drive input gear bearing and the drive input gear due to the force in the thrust direction, but it is driven by setting {the thrust force of the helical gear <the magnitude of the pressing force by the biasing member}. Wear, vibration, heat generation, etc. of the entire apparatus are reduced. In addition, since a lotus gear is originally widely used in the drive input gear train for the purpose of improving the meshing rate, in such a drive device, {the thrust force of the lotion gear + the pressing force by the biasing member } Both acted on the drive input gear. In contrast to such a drive device, only the {thrust gear thrust force} acts in the drive device of this embodiment, so that the effect of reducing friction is great. The configuration in which the bearing of the drive input gear and the drive input gear abut is effective when positioning the drive input gear and the photosensitive drum in the axial direction at this location. However, if priority is given to suppressing the sliding of the drive input gear over the axial positioning, a configuration in which the thrust force is not generated by using the drive input gear as a spur gear may be selected.

  In this embodiment, the urging force of the compression coil spring is transmitted to the input drive gear through the pressurizing member as the urging member, but the plate spring as the urging member, the coil spring with a devised end shape, Further, the input drive gear may be brought into direct contact using a torsion coil spring or the like.

  In addition, when it is necessary to control the photosensitive drum to rotate in the reverse direction in the paper conveyance direction, the drum driving input gear is driven to rotate in the reverse direction. Then, a force in a direction in which the coupling on the drum drive input gear side is pulled out is generated by an axial force generated by the shape of the engaging portion of the coupling, and there is a problem that the coupling is released. In such a case, it is possible to increase the urging force of the urging member that urges the drum driving input gear to the coupling on the photosensitive drum side so that the coupling on the drum driving input gear side does not come off due to reverse rotation driving. is there. However, by using the driving device according to the present embodiment in such a configuration, a merit that can reduce wear, vibration, heat generation, and increase in driving load can be obtained more greatly. In the present embodiment, an example in which the user and the serviceman are manually operated as input means for operating the locking member 49 in a screw shape in the coupling operation is shown. However, a motor or an actuator may be used as a power source for the purpose of improving usability and luxury.

  When shifting from the state of FIG. 2B to the state of FIG. 2C and FIG. 2D, the shape of the concavo-convex portion is out of phase in the rotational direction of the driven side coupling and the input side coupling. And the coupling end portions of the two interfere with each other, and a biasing force is applied to the contact portion. Even in such a case, when the input side is driven and rotated, the coupling is engaged at a position where the circumferential phase of the concavo-convex portion is matched, and the state of FIG. 2 (c) is shifted to the state of FIG. 2 (d). Even in such a case, the final drive state is the same as that obtained after the above-described procedure, and the effect of the present invention is not impaired.

{Coupling release operation and cartridge removal operation}
The procedure of the coupling release operation and the cartridge removal operation is the reverse of the procedures shown in FIGS. 2 (a) to 2 (d) and FIGS. 5 (c), (d) to (e), (f). It becomes the operation.

  As described above, in the first exemplary embodiment, the process cartridge is used as the unit that can be attached to and detached from the image forming apparatus. However, the unit may be a developing cartridge provided with developing means, a developer unit containing developer, or an intermediate transfer body unit having an intermediate transfer body to which an image is transferred.

  A second embodiment will be described below. The operations relating to paper feeding, image formation, fixing and paper ejection and the shape of the coupling in the second embodiment are the same as those in the first embodiment, the configuration related to the mounting direction of the cartridge and the mounting / demounting of the cartridge, and the photosensitive drum Since only the energizing method is different, the description is omitted.

  3A to 3E and FIG. 6A regarding the mounting operation of the image forming process cartridge (hereinafter referred to as the cartridge), the coupling connection operation, the coupling connection release operation, and the removal of the cartridge in the second embodiment. ) To (b). FIG. 3A is a cross-sectional view from the front side of the apparatus schematically showing the cartridge mounting operation. FIG. 3B is a front view of the apparatus schematically showing a state in which, after the cartridge is mounted, the opening / closing cover for cartridge replacement is closed but the coupling phase is not engaged because the coupling phase is not matched. FIG. FIG. 3C is a cross-sectional view from the front side of the apparatus schematically showing a state in which a cartridge is mounted by a user or a serviceman, the couplings are engaged with each other, and drive input from the main body drive source is not performed. is there. FIG. 3D is a cross-sectional view from the front side of the apparatus schematically showing a state in which the driving apparatus is being driven. FIG. 6A is a perspective view of the image processing apparatus in the second embodiment, and FIG. 6B is a diagram showing the relationship between the cartridge and the transfer roller 11 in the second embodiment.

{Cartridge loading operation}
Next, the cartridge mounting operation will be described with reference to FIGS. 3 (a) to 3 (b) and FIGS. 6 (a) to 6 (b). 3A to 3D are cross-sectional views as viewed from the front side of the apparatus, and the paper during printing is conveyed to the back side in the depth direction in the figure.

  FIG. 6A is a perspective view of the image processing apparatus in the second embodiment. In the image processing apparatus in the second embodiment, as shown in FIG. 6A, an image forming process cartridge as a unit to be attached and detached can be attached and detached in a direction perpendicular to the sheet conveying direction in the apparatus.

  FIG. 3A shows the main body side drive unit during the mounting operation of the cartridge and the cartridge in a non-mounted state. In FIG. 3A, P represents a process cartridge, which is inserted in the direction of arrow J by the user's mounting operation. The direction J is a direction orthogonal to the sheet conveying direction in the image forming apparatus. 42 is a photosensitive drum, 43 is a housing of the cartridge, and 41 is a coupling as a first engaging portion provided at the end in the longitudinal direction of the photosensitive drum. 50 is a main body side drive unit, 45 is a drive input gear, 45a is an input side coupling as a second engaging portion, 46 is a bearing of the drive input gear on the side close to the cartridge, and 47 is on the side far from the cartridge. It is a bearing of a drive input gear. The drive input gear 45 is supported by the two bearings so as to be rotatable and movable in the axial direction. Reference numeral 51 denotes a main body frame metal plate, and reference numeral 55 denotes a metal plate that forms a frame of the drive unit. Reference numeral 52 denotes a pressing member 52 that contacts the drive input gear in the state of FIG. 2A and applies an urging force to the drive input gear toward the cartridge in the axial direction (in the direction of arrow G in the figure). The compression coil spring 54 applies a biasing force to the drive input gear 45 through the pressure member 52. 53 is a guide member of the pressure member, and supports the other end of the compression coil spring. The guide member 53 is fixed to the frame side plate 55 of the drive unit. In the second embodiment, when the cartridge is not mounted, the pressing member 52 is provided with an abutting portion 55b on the sheet metal side where the abutting surface 52b forms the frame of the drive unit as shown in FIG. The drive input gear 45 does not receive a biasing force from the pressing member. For this reason, the drive input gear side coupling 45 a stands by at a position protruding from the end of the bearing 46. However, there is no problem because the operation for mounting the cartridge in the direction of arrow E in the first embodiment is not performed.

  In the second embodiment, a gear part 60 that can rotate integrally with the photosensitive drum is provided on the other end of the driven side coupling of the photosensitive drum 42. (See FIG. 6B.) The gear 60 functions as an input gear that transmits the driving force of the photosensitive drum to another driving unit outside the cartridge unit. In this embodiment, the gear 60 drives the transfer roller 11 as a non-driving member. The transfer roller 11 is rotationally driven via the gear 11a. In this embodiment, a helical gear is used as this gear, and the gear is arranged so that the axial load generated when the photosensitive drum is driven is generated in the same direction as the arrow J in FIG. When the cartridge is mounted by a user operation, the cartridge is in the state shown in FIG. 3B or 3C. That is, when the phase in the rotational direction of the input side coupling and the driven side coupling does not mesh at the cartridge insertion stage, the phase in the rotational direction of the input side coupling and the driven side coupling is changed to the state of FIG. If they are engaged, the state shown in FIG.

{Coupling connection}
In the second embodiment, when the cartridge is mounted by a user or a service person, the cartridge is generally positioned by a positioning member (not shown) with respect to the product vertical direction of the cartridge, the product horizontal direction, the product longitudinal direction, and the rotation direction around the photosensitive drum. Is done. In the configuration in which the cartridge is attached and detached in the direction orthogonal to the sheet conveying direction in the apparatus, the state shown in FIG. 3C is obtained when the phases in the rotation direction of the input side coupling and the driven side coupling are engaged when the cartridge is inserted. On the other hand, when the phase in the rotational direction of the input side coupling and the driven side coupling does not mesh at the cartridge insertion stage, the state shown in FIG. In the state of FIG. 3B, the driven coupling end face 41b and the input coupling end face 45f abut each other. Then, the drive input gear 45 is pushed in the axial direction from the position of FIG. 3A, and the drive input gear 45 and the driven side coupling 41 receive the urging force of the urging member 54. When the drive input gear 45 is driven to rotate from the state shown in FIG. 3B, the couplings engage with each other at a position where the rotational direction phases of the concave and convex portions of the coupling match each other. It will be in the state of 3 (d).

  Thus, in the second embodiment, there is no need for a coupling connection and release mechanism interlocked with other parts as used in the first embodiment. Even if the state shown in FIG. 3B is entered once and then the state shown in FIG. 3C is reached, the final driving state is the same in both cases.

  FIG. 3C shows a state in which the cartridge is mounted by a user or a serviceman, and drive input from the main body drive source has not yet been performed at this point. At this time, as shown in FIG. 3C, the driven side coupling 41a and the input side coupling 45a are partially engaged. The abutting surfaces in the axial direction of the driven side coupling 41a and the input side coupling 45a are 41b and 45e, respectively. However, when no driving input is performed, they do not abut and there is a clearance. Further, at this time, the contact surface between the pressure member and the drive input gear is in contact, but the pressure member abutment portion 52b is received by the abutment portion 55b on the sheet metal side forming the frame of the drive unit. Therefore, the urging force by the urging member 54 is not applied to the drive input gear. A bearing member 56 for the driven side coupling is fixed to the housing 43 of the cartridge. In this embodiment, the end portion 56a of the bearing member abuts against the end surface 46b of the bearing 46 of the drive input gear on the main body frame side. Further, the other end surface 56 b of the bearing 56 abuts against the longitudinal abutting surface 41 c of the driven side coupling 41. The position of the photosensitive drum in the longitudinal direction is determined by the contact of these abutting portions. Driving input from the main body driving source is performed in a state where the cartridge is mounted. Then, a thrust force is generated in the photosensitive drum by the drive train helical gear to the downstream driving portion of the photosensitive drum, and the photosensitive drum, the driven side coupling 41, and the bearing 56 are moved in the direction of arrow J. And positioned. On the other hand, when the input side coupling is driven, a force is generated in the driven side coupling 41a and the input side coupling 45a in the direction in which they are attracted to each other in the axial direction due to the shape of the contact surface. As a result, as shown in FIG. 3D, the abutting surfaces 41b and 45e abut against each other, and both rotate integrally. The drive input gear 45 receives the thrust force between the couplings and moves in the H direction. As shown in FIG. 3D, the contact surface 45b of the drive input gear with the pressure member and the contact surface 52a of the pressure member are It is in a separated state.

  FIG. 3D shows a state in which the driving device is being driven, and includes a case where the image forming apparatus is performing a printing operation. In the driving state, since the drive input gear is further moved in the H direction from the position of FIG. 3C, the surface 45b on which the drive input gear is urged by the pressure member and the contact surface 52a of the pressure member are separated. . Further, the end face 45d of the drive input gear and the end 46a of the drive input gear fixed to the main body are arranged with a clearance so as not to slide in the drive state. That is, in this embodiment, the drive input gear and the pressure member are separated by the thrust direction force of the drive train helical gear to the photosensitive drum downstream drive unit outside the unit to be attached and detached, and the drive input gear and the bearing 46 are separated. Spacing is ensured. Therefore, wear, vibration, heat generation, and increase in driving load between these parts do not occur. On the other hand, the driven side coupling end surface 41c and the bearing end surface 56b slide due to the thrust force acting on the photosensitive drum. However, by increasing the magnitude of the pressing force by the urging member 54 to be greater than the magnitude of the thrust force of the helical gear, wear, friction noise, vibration, heat generation, and increase in driving load of the entire driving device are reduced. In addition, since a lotus gear is originally widely used in the drive input gear train for the purpose of improving the meshing rate, in such a drive device, {the thrust force of the lotion gear + the pressing force by the biasing member } Both acted on the drive input gear. In contrast to such a drive device, only the {thrust gear thrust force} acts in the drive device of this embodiment, so that the effect of reducing friction is great. Further, since the driven side coupling end surface 41c and the bearing end surface 56b are both internal parts of the cartridge unit, they are replaced with new parts by periodic replacement of the cartridge, and therefore, they are not worn beyond the life of the cartridge unit. There are benefits. Further, it is possible to position the photosensitive drum in the axial direction with a small number of parts with respect to the main body frame. However, if priority is given to suppressing the sliding of the drive input gear over the axial positioning, a configuration in which the thrust force is not generated by using the drive input gear as a spur gear may be selected.

  In addition, when it is necessary to control the photosensitive drum to rotate in the reverse direction in the paper conveyance direction, the drum driving input gear may be driven to rotate in the reverse direction. At this time, there is a problem that the coupling force is released due to the force in the direction in which the coupling on the drum drive input gear side comes off due to the axial force generated by the shape of the engaging portion of the coupling. In such a case, it is possible to increase the urging force of the urging member that urges the drum driving input gear to the coupling on the photosensitive drum side so that the coupling on the drum driving input gear side does not come off due to reverse rotation driving. is there. However, by using the driving device according to the present embodiment in such a configuration, a merit that can reduce wear, vibration, heat generation, and increase in driving load can be obtained more greatly.

DESCRIPTION OF SYMBOLS 1 Image processing apparatus main body P Process cartridge 41 1st coupling 42 Photoconductor drum 45 Drive input gear 45a 2nd coupling (input side coupling)
45b Surface where the drive input gear is biased by the pressure member 45c Drive input gear tooth surface 45d Abutment surface of the drive input gear 45b End portion on the non-cartridge side 45d Abutment surface 45e Axial direction with the first coupling Abutting surface 45f End face of input side coupling 45g Positioning shape 48 Drive upstream gear adjacent to drive input gear 49 Locking member 49a Operation side cam portion 52 Pressure member 52a Contact surface of drive member with drive input gear 52b Pressing member abutting portion 54 Compression coil spring as an urging member 56 Non-drive coupling bearing 56a Main body bearing surface 56b Abutting surface with driven side coupling 57 Cartridge in the first embodiment Open / close cover for replacement 58 Link bar 59 Open / close cover for cartridge replacement in the second embodiment 60 Transfer roller drive input helical gear provided at the end of the optical drum

Claims (8)

In the image forming apparatus in which the unit is removable,
When the unit is mounted on the apparatus main body of the image forming apparatus, a connection position for connecting a driving force receiving portion provided in the unit for transmitting a driving force to the unit, and the driving force receiving portion A driving force transmission member that takes a separated position and is configured to generate a force in a direction approaching the driving force receiving portion in the axial direction when rotating in conjunction with the driving force receiving portion. A driving force transmission member;
A biasing member that biases the driving force transmission member in a direction in which the driving force transmission member moves from the separated position to the coupling position;
A pressure member provided between the driving force transmission member and the biasing member, the pressure member transmitting a biasing force from the biasing member to the driving force transmission member;
When the driving force transmission member rotates in connection with the driving force receiving portion, a regulating portion that restricts the movement of the pressing member at a position where the pressing member does not contact the driving force transmission member;
An image forming apparatus.   One of the driving force transmission member and the driving force receiving portion is a twisted convex portion having a triangular cross section, and the other is a twisted concave portion having a triangular cross section, and the driving force transmitting member is connected to the driving force receiving portion. The image forming apparatus according to claim 1, wherein a force in a direction approaching the driving force receiving portion is generated in the axial direction when the rotation is performed.   The driving force transmission member has a helical gear that meshes with a driving gear provided in the apparatus main body, and when the driving force transmission member rotates in connection with the driving force receiving portion, the driving force transmission member The image forming apparatus according to claim 1, wherein a force in a direction approaching the driving force receiving portion is generated.   Further, the image forming apparatus includes the opening through which the unit is attached to the apparatus main body of the image forming apparatus, the opening / closing cover for opening / closing the opening, and the driving in conjunction with the opening operation of the opening / closing cover. The image forming apparatus according to claim 1, further comprising a connecting member that moves the force transmission member from the connecting position to the separated position.   5. The image forming apparatus according to claim 1, wherein the unit is detachable from the apparatus main body in a direction intersecting an axial direction of the driving force transmission member.   The image forming apparatus according to claim 1, wherein the unit is detachable from the apparatus main body in an axial direction of the driving force transmission member.   The image forming apparatus according to claim 1, wherein the unit is a process cartridge having a photosensitive drum on which an electrostatic latent image is formed.   The image forming apparatus according to claim 1, wherein the unit is an intermediate transfer body unit including an intermediate transfer body to which an image is transferred.

Images