JP3780059B2 - Electrophotographic image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention is a process cartridge.RemovableThe present invention relates to an electrophotographic image forming apparatus. Here, the electrophotographic image forming apparatus is an object that forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), a facsimile machine, a word processor, and the like.
[0002]
The process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum are integrally formed, and the cartridge can be attached to and detached from the image forming apparatus main body. In addition, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive drum are integrally formed into a cartridge that can be attached to and detached from the main body of the image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive drum are integrated into a cartridge so that it can be attached to and detached from the apparatus main body.
[0003]
[Problems to be solved by the invention]
Any of the techniques described in the gazettes described in the following description of the prior art is very effective as a configuration for transmitting a rotational force to the photosensitive drum. The present invention is a further development of the above-described prior art.
[0004]
  An object of the present invention is to provide a process cartridge capable of improving the rotational speed of an electrophotographic photosensitive drum.RemovableAn object of the present invention is to provide an electrophotographic image forming apparatus.
[0005]
  Another object of the present invention is to provide an apparatus for a process cartridge by generating a thrust during operation to drive the process cartridge on the apparatus main body side or the non-drive side when transmitting the driving force. An object of the present invention is to provide an electrophotographic image forming apparatus capable of improving image quality obtained by improving positioning accuracy with respect to a main body.
[0006]
Still another object of the present invention is to provide a shaft coupling capable of achieving the above object, and during driving, the shaft coupling moves to a joint portion on the process cartridge side to realize a reliable connection state, and further, a rotating shaft. An electrophotography equipped with a shaft coupling device that prevents the shaft coupling from coming off due to a thrust reaction force or a rotation reaction force due to the twist angle of the shaft, and does not apply a rotational force to the driving side and the driven side when releasing An object is to provide an image forming apparatus.
[0007]
[Means for Solving the Problems]
    According to a first aspect of the present application, there is provided an electrophotographic image forming apparatus for detaching a process cartridge and forming an image on a recording medium.
a. An electrophotographic photosensitive drum;
Process means acting on the electrophotographic photosensitive drum;
Twist polygonal column protrusions provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
A cartridge mounting portion for detachably mounting a process cartridge having
b. A rotating body that is connected to the driving source, has a twisted hole with a polygonal cross section at the center, and is supported so as to be rotatable and not move in the axial direction;
c. A twisted polygonal column fitted in a twisted hole of the rotating body is provided at one end, and a twist angle and a twist direction which are engaged with and disengaged from a protrusion of the electrophotographic photosensitive drum at the other end are twisted at the one end. A coupling shaft that has a twisted hole having the same polygonal cross section as the polygonal column, and is rotatably supported in the axial direction;
d. The coupling shaftSaidA spring member biasing in the direction of the electrophotographic photosensitive drum;
e.SaidA twisted hole in the coupling shaftSaidA twisted polygonal column protrusion provided at one end in the longitudinal direction of the electrophotographic photosensitive drum, and a disengaged position;SaidA twisted hole in the coupling shaftSaidAn axially moving means of the coupling shaft provided to take a position to engage with a twisted polygonal column protrusion provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
f. Conveying means for conveying the recording medium;
g. The coupling shaft isSaidA spacer member inserted into a space generated by sliding in the axial direction in order to couple with the electrophotographic photosensitive drum;
An electrophotographic image forming apparatus comprising:
[0010]
    No. related to this application2The present invention is an electrophotographic image forming apparatus for detaching a process cartridge and forming an image on a recording medium.
a. An electrophotographic photosensitive drum;
Process means acting on the electrophotographic photosensitive drum;
Twist polygonal column protrusions provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
A cartridge mounting portion for detachably mounting a process cartridge having
b. A rotating body that is connected to the driving source, has a twisted hole with a polygonal cross section at the center, and is supported so as to be rotatable and not move in the axial direction;
c. A twisted polygonal column fitted in a twisted hole of the rotating body is provided at one end, and a twist angle and a twist direction which are engaged with and disengaged from a protrusion of the electrophotographic photosensitive drum at the other end are twisted at the one end. A coupling shaft that has a twisted hole having the same polygonal cross section as the polygonal column, and is rotatably supported in the axial direction;
d. The coupling shaftSaidA spring member biasing in the direction of the electrophotographic photosensitive drum;
e.SaidA twisted hole in the coupling shaftSaidA twisted polygonal column protrusion provided at one end in the longitudinal direction of the electrophotographic photosensitive drum, and a disengaged position;SaidA twisted hole in the coupling shaftSaidAn axially moving means of the coupling shaft provided to take a position to engage with a twisted polygonal column protrusion provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
f. A flange portion having a radial bearing in which the outer periphery of the other end having a twisted hole having a polygonal cross section of the coupling shaft is rotatably and axially movable, and the rotating body is axially moved.SaidIntegrated with a thrust bearing that is supported so as not to move to the electrophotographic photosensitive drum side,SaidWith flangeSaidBetween the thrust bearings, the coupling shaftAxial directionA coupling bearing having an opening through which the moving means is inserted;
g. Conveying means for conveying the recording medium;
An electrophotographic image forming apparatus comprising:
[0011]
    No. related to this application3In the electrophotographic image forming apparatus for detaching a process cartridge and forming an image on a recording medium,
a. An electrophotographic photosensitive drum;
Process means acting on the electrophotographic photosensitive drum;
Twist polygonal column protrusions provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
A cartridge mounting portion for detachably mounting a process cartridge having
b. A rotating body that is connected to the driving source, has a twisted hole with a polygonal cross section at the center, and is supported so as to be rotatable and not move in the axial direction;
c. A twisted polygonal column that fits into a twisted hole of the rotating body is provided at one end, and the other end engages and disengages from the protrusion of the electrophotographic photosensitive drum. A twist angle and a twist direction are twisted at the one end. A coupling shaft that is the same as the polygonal column and has a polygonal column twisted hole, a flange between the one end and the other end, and is rotatably supported in the axial direction.
d. The coupling shaftSaidA spring member biasing in the direction of the electrophotographic photosensitive drum;
e. An opening / closing member provided in the cartridge mounting portion;
f. A flange portion having a radial bearing in which the outer periphery of the other end of the twisted hole having a polygonal cross section of the coupling shaft is rotatably and axially movable, and the rotating body is axially moved.SaidIntegrated with a thrust bearing that is supported so as not to move to the electrophotographic photosensitive drum side,SaidWith flangeSaidBetween the thrust bearing portion and the thrust bearing portion;SaidA coupling bearing having an opening through which a cam lever having a spacer that moves forward and backward between the flange of the coupling shaft is inserted;
g. The opening and closing member has a flange interposed between the coupling bearing and the flange of the coupling shaft.SaidA cam member coupled to interlock with the opening / closing operation of the opening / closing member;
h. Conveying means for conveying the recording medium;
An electrophotographic image forming apparatus comprising:
[0012]
    No. related to this application4According to the present invention, the rotating body is a helical gear.3An electrophotographic image forming apparatus according to any one of the inventions.
[0013]
    No. related to this application5In the invention of the present invention, the coupling shaft is fastened and fixed to a side plate that supports a member that transmits power to the rotating body. A compression spring for urging the coupling shaft toward the electrophotographic photosensitive drum side,SaidInsert one end of the compression spring into the small diameter side of the stepped caulking shaft.SaidSmall diameter side andSaidThe other end of the compression spring is formed inside the coupling shaft, abutting against the stepped portion which is the boundary surface on the large diameter side.With stepCaulking shaftSaidThe first to second features are characterized by being contracted in contact with a thrust flange portion fitted on the small diameter side.4An electrophotographic image forming apparatus according to any one of the inventions.
[0014]
    No. related to this application6The invention of the aboveTwisted coupling shaftThe cross section of the hole is substantially triangular, and the shape of the protrusion is a twisted substantially triangular prism, wherein the corners of the substantially triangular prism are chamfered.4An electrophotographic image forming apparatus according to any one of the inventions.
[0015]
    No. related to this application7The invention ofSaidIn the cartridge mounting partSaidOpen when removing or installing the process cartridge,SaidIn the cartridge mounting partSaidInstall and close the process cartridgeSaidA first or second member having an opening / closing member in the cartridge mounting portion and an interlocking member for interlocking the opening / closing member and the axial movement means of the coupling shaft.2The electrophotographic image forming apparatus described in the invention.
[0017]
    No. related to this application8The invention is separated from the body frameThe aboveA side plate that supports a member that transmits power to the rotating body, and the coupling shaft is fitted to a caulking shaft fixed to the side plate;SaidBy being rotatably supported by the body frameSaidPositioning is performed in a plane perpendicular to the axis of the coupling shaft.To thirdAn electrophotographic image forming apparatus according to any one of the inventions.
[0023]
[Prior art]
An electrophotographic image forming apparatus using an electrophotographic image forming system forms a latent image by performing selective exposure according to image information on an electrophotographic photosensitive drum uniformly charged by a charging unit. Then, the latent image is developed with toner by a developing unit to form a toner image. Thereafter, the toner image formed on the electrophotographic photosensitive drum is transferred to a recording medium by a transfer unit to form an image.
[0024]
Conventionally, in an image forming apparatus using an electrophotographic image forming process, the electrophotographic photosensitive drum and the process means acting on the electrophotographic photosensitive drum are integrally formed into a cartridge, and the cartridge is attached to and detached from the image forming apparatus main body. A process cartridge system that enables this is adopted. According to this process cartridge system, the apparatus can be maintained by the user himself / herself without depending on the service person, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in image forming apparatuses.
[0025]
In such a process cartridge, in order to drive at least the electrophotographic photosensitive drum, when the process cartridge is mounted on the image forming apparatus main body, a power transmission member and an electrophotographic photosensitive member serving as a drive source on the image forming apparatus main body side are provided. The body drum is connected.
[0026]
Here, various methods have been considered for rotationally driving the electrophotographic photosensitive drum. One method is described in Japanese Patent Laid-Open No. 62-65049, in which a pin fixed to a side surface of a gear provided in the main body of the image forming apparatus is attached to a side surface of the gear provided to the photosensitive drum. In this method, the photosensitive drum is rotated by being fitted in the provided recess.
[0027]
As another method, as described in JP-A-63-4252, there is a method in which the photosensitive drum is rotated by fitting with a helical gear provided in the main body of the image forming apparatus.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments according to the present invention will be described with reference to the drawings.
[0029]
In the following description, the longitudinal direction is a direction perpendicular to the recording medium conveyance direction and along the surface of the recording medium, and coincides with the axial direction of the photosensitive drum.
[0030]
[Embodiment 1]
First, the process cartridge B according to the embodiment and the electrophotographic image forming apparatus A to which the process cartridge B can be detachably mounted will be specifically described with reference to FIGS. 1 to 6. Here, as an order of description, first, the overall configuration of the process cartridge B and the electrophotographic image forming apparatus A that is used by mounting the process cartridge B will be described with reference to FIGS. 1 to 6, and then referring to FIGS. 7 to 13. Next, the structure of the shaft coupling that is the driving force transmission mechanism between the process cartridge B and the image forming apparatus main body 13 will be described.
[0031]
{overall structure}
FIG. 1 is a cross-sectional explanatory view of a laser beam printer which is an electrophotographic image forming apparatus A to which a process cartridge B is detachably mounted.
[0032]
As shown in FIG. 1, the printer A irradiates the photosensitive drum 7 with laser light based on image information from the optical system 1 to form a latent image on the photosensitive drum 7, and this latent image is used with toner. Development to form a toner image. In synchronization with the formation of the toner image, the recording medium 2 is transported from the paper feed cassette 3a by transport means 3 including a pickup roller 3b and a pair of transport rollers 3d. The toner image formed on the photosensitive drum 7 is transferred to the recording medium 2 by applying a voltage to the transfer roller 4 as transfer means. Then, the recording medium 2 is guided by the guide plate 3 f and conveyed to the fixing unit 5. The fixing unit 5 includes a fixing rotation band 5c including a driving roller 5a and a heater 5b, and applies heat and pressure to the passing recording medium 2 to fix the transferred toner image on the recording medium 2. Then, the recording medium 2 is conveyed by the discharge roller pair 3g and discharged to the discharge unit 6 through the reverse conveyance path.
[0033]
The printer A can also be manually fed by a manual feed tray and a roller (description is omitted).
[0034]
On the other hand, the process cartridge B includes an electrophotographic photosensitive drum and at least one process means. Here, as the process means, for example, a charging means for charging the electrophotographic photosensitive drum, a developing means for developing a latent image formed on the electrophotographic photosensitive drum, and a toner remaining on the surface of the electrophotographic photosensitive drum are cleaned. Cleaning means or the like.
[0035]
As shown in FIGS. 1 and 2, the process cartridge B of the present embodiment includes an electrophotographic photosensitive drum 7, a charging roller 8, an exposure opening 9, a developing unit 10, and a cleaning unit 11. Then, the process cartridge B rotates the photosensitive drum 7 from the apparatus main body 13 by a shaft coupling device described later. Then, the surface is uniformly charged by applying a voltage to the charging roller 8 which is a charging means, and information light from the optical system 1 is exposed to the photosensitive drum 7 through the exposure opening 9 to form a latent image. Development is performed by the developing means 10.
[0036]
The developing means 10 feeds the toner in the toner storage portion 10a with the toner feeding member 10b, rotates the developing roller 10d with a built-in fixed magnet 10c, and rotates the toner layer to which the triboelectric charge is applied by the developing blade 10e. A toner image is formed on the surface of 10d and transferred to the photosensitive drum 7 in accordance with the latent image, thereby forming a visible image. The toner image is transferred to the recording medium 2 by applying a voltage having a polarity opposite to that of the toner image to a transfer roller 4 provided in the apparatus main body 13. Residual toner is removed from the photosensitive drum 7 after the transfer by the cleaning means 11. That is, the remaining toner is scraped off by the cleaning blade 11a. The toner scraped off is collected in the waste toner reservoir 11c by the squeeze sheet 11b.
[0037]
The charging roller 8 is in contact with the photosensitive drum 7 and is rotated following the photosensitive drum 7. Further, the cleaning blade 11 a is in contact with the photosensitive drum 7.
[0038]
Further, the process cartridge B welds a toner frame 12a having a toner storage portion 10a for storing toner and a developing frame 12b holding a developing member such as the developing roller 10d (ultrasonic welding in the present embodiment). To construct a development unit. The developing unit is coupled to a cleaning frame 12c that supports the photosensitive drum 7, the charging roller 8, and the cleaning unit 11 so as to be able to swing with respect to each other. The drum 7 and the large diameter portions at both ends of the developing roller 10d are pressed against each other. The process cartridge B is detachably mounted by a user on a later-described cartridge mounting means provided in the apparatus main body 13 from a direction intersecting the longitudinal direction of the photosensitive drum 7 (see FIGS. 5 and 6). . The cleaning frame 12c is provided with a mounting guide 12c4 in the vicinity of the bearing 12c2 that supports the drum shaft 36a of the photosensitive drum 7 shown in FIG. Further, a mounting guide 12c5 is integrally formed with the bearing 34 attached to the cleaning frame 12c shown in FIG. The mounting guides 12c4 and 12c5 are guided by the guide portions 35a and 35c shown in FIGS. 5 and 6 when the process cartridge B is mounted.
[0039]
As the cartridge mounting means, as shown in FIG. 5, cartridge mounting guide members 35 are mounted on both the left and right side surfaces of the cartridge mounting space provided in the apparatus body 13 (FIG. 5 shows one side surface, FIG. The left and right guide members 35 are provided with guide portions 35a and 35c that are used as guides when the process cartridge B is inserted. Cylindrical bosses 34a, bearings 12c2, and mounting guides 12c4 and 12c5 formed so as to protrude from both sides in the longitudinal direction of the cartridge frame are guided and inserted into the guide portions 35a and 35c. The cylindrical boss 34a is supported by a U groove 35d provided at the end of the guide portion 35c, and the bearing 12c2 is fitted into the U groove 35d provided at the end of the guide portion 35a. In order to mount the process cartridge B on the apparatus main body 13, the opening / closing cover 14 that can be opened and closed with respect to the apparatus main body 13 is opened around the shaft 14a. Then, the process cartridge B is mounted on the image forming apparatus main body 13 by closing the opening / closing cover 14. The open / close cover 14 is also opened when the process cartridge B is taken out from the apparatus main body 13.
[0040]
When the process cartridge B is mounted on the image forming apparatus main body 13, as will be described later, the cartridge side shaft coupling member and the apparatus main body side shaft coupling member are coupled in conjunction with the closing operation of the opening / closing cover 14, and the photosensitive drum 7 etc. can be rotated by receiving a drive from the apparatus main body 13.
[0041]
{Shaft coupling device and drive configuration}
Next, the configuration of the shaft coupling which is a drive transmission mechanism that transmits the driving force from the image forming apparatus main body 13 to the process cartridge B will be described.
[0042]
As shown in FIGS. 7, 8, and 9, a process cartridge side shaft coupling member is provided at one end in the longitudinal direction of the photosensitive drum 7 attached to the process cartridge B. This shaft coupling member is obtained by providing a coupling flange 15 (columnar shape) on a drum flange 37 fixed to one end of the photosensitive drum 7, and a drum shaft protrusion on the tip surface of the coupling protrusion 15. A portion 16 is formed. The end surface of the convex portion 16 is parallel to the end surface of the coupling convex shaft 15. The convex shaft 15 functions as a rotation shaft of the photosensitive drum 7. In the present embodiment, the drum flange 37, the coupling convex shaft 15 and the drum shaft convex portion 16 are integrally provided.
[0043]
As shown in FIG. 7, the coupling convex shaft 15 and the drum shaft convex portion 16 are positioned coaxially with the axis of the photosensitive drum 7 when the drum flange 37 is attached to one end of the photosensitive drum 7. It is provided in the drum flange 37 so that it may do. Reference numeral 37b denotes a fitting portion that is fitted to the inner surface of the drum cylinder 37a when the drum flange 37 is attached to the photosensitive drum 7. The drum drum flange 37 is attached to the photosensitive drum 7 by “caulking” or “adhesion”. The drum cylinder 7a is covered with a photosensitive layer 7b (see FIG. 7).
[0044]
A drum flange 36 is fixed to the other end side of the photosensitive drum 7. The drum flange 36 is integrally molded with a drum shaft 36a and a spur gear 36b (see FIG. 7).
[0045]
When the process cartridge B is mounted on the apparatus main body 13, the bearing 12c2 is positioned by being fitted into the U groove 35b (see FIG. 5) of the apparatus main body 13, and is molded integrally with the drum flange 36. The gear 36 b meshes with a gear (not shown) that transmits a driving force to the transfer roller 4.
[0046]
Further, since the developing unit side is heavier than the cleaning frame 12c side with respect to the photosensitive drum 7, the abutting portion 12c1 provided on the cleaning frame 12c is fixed to the apparatus main body 13 as shown in FIG. The upper surface of the developing unit is pressed by a compression coil spring 14b that is in contact with 13a and provided on the back surface of the opening / closing cover 14.
[0047]
The drum flanges 37 and 36 are made of a resin material such as polyacetal, polycarbonate, polyamide, and polybutylene terephthalate. However, other materials may be appropriately selected and used.
[0048]
A cylindrical boss 34a concentric with the coupling convex shaft 15 is provided on the cleaning frame 12c around the drum shaft convex portion 16 of the coupling convex shaft 15 of the process cartridge B (FIG. 3, FIG. 3). (See FIG. 7). The boss 34a protects the drum shaft convex portion 16 when the process cartridge B is attached and detached, and is protected from scratches and deformation caused by an external force. Therefore, it is possible to prevent rattling and vibration during coupling driving due to damage to the drum shaft convex portion 16.
[0049]
Further, the shape of the boss 34a is not limited to the circular shape shown in the present embodiment, and it is sufficient that the boss 34a can be guided by the guide 35c and supported by the U-groove 35d. Instead of a cylindrical shape, it may be a circular arc shape with a circular shape. Further, in the present embodiment, an example is shown in which a bearing 34 for rotatably supporting the coupling convex shaft 15 and a cylindrical boss 34a are integrally molded and screwed (not shown) to the cleaning frame 12c. However (see FIGS. 3 and 7), the bearing 34 and the boss 34a may be separate.
[0050]
In the present embodiment, the drum shaft 36a is fitted to the bearing 12c2 provided on the cleaning frame 12c (see FIGS. 4 and 7), and the inner surface of the bearing 34 attached to the cleaning frame 12c. The photosensitive drum 7 is attached to the cleaning frame 12c of the process cartridge B in a state where the coupling convex shaft 15 is fitted. Therefore, the photosensitive drum 7 rotates about the coupling convex shaft 15 and the drum shaft 36a. In the present embodiment, the photosensitive drum 7 is attached to the cleaning frame 12c so as to be movable in the axial direction as shown in FIG. This is due to consideration of mounting tolerances. However, the present invention is not limited to this, and the photosensitive drum 7 may be attached so as not to move in the axial direction with respect to the cleaning frame 12c.
[0051]
That is, the end surface 37c (end surface of the helical gear 37a) of the drum flange 37 is slidably in contact with the end surface 34b of the bearing 34, and the end surface 36c of the drum flange 36 is slidably in contact with the inner surface of the cleaning frame 12c. You may arrange in.
[0052]
The shape of the drum shaft convex portion 16 is a twisted polygonal column as shown in FIG. 8, and more specifically, a shape that is a substantially regular triangular prism in the axial direction and twisted so that the phase in the rotational direction gradually differs in the axial direction. The ridgeline of the substantially regular triangular prism is chamfered. Further, the coupling shaft concave portion 17 fitted to the drum shaft convex portion 16 is a hole twisted so that the axis of the polygonal section is gradually different in the axial direction in the rotational direction. The coupling shaft recess 17 is provided at one end of the coupling shaft 18. The other end side of the coupling shaft flange 19 is coaxial with the coupling shaft recess 17 and also in the rotational direction according to the axial direction. A polygonal column that is twisted at the same pitch so that the phases are different, more specifically, a substantially equilateral triangular prism, and a corner portion of the substantially equilateral triangular prism has a coupling shaft convex portion 20 that is chamfered. And the gear side coupling recessed part 21 fitted with the said coupling axis | shaft convex part 20 is a hole twisted so that the axis | shaft of a polygonal cross section may gradually change the phase of a rotation direction to an axial direction. And this gear side coupling recessed part 21 is provided in the center of the drum drive gear 22 arrange | positioned as a rotary body by the side of the apparatus main body 13. FIG. The gear-side coupling recess 21 is a substantially triangular prism in cross section, and is a hole having a substantially triangular cross section so that the coupling shaft convex portion 20 just fits. The gear-side coupling concave portion 21 and the coupling shaft convex portion 20 may be a female screw and a male screw having large leads that are precisely fitted.
[0053]
A driving force from a driving motor (not shown) is transmitted to the drum driving gear 22 by a gear train (not shown), and the drum driving gear 22 transmits a driving force to the process cartridge B. The driving force is transmitted from the drum driving gear 22 to the coupling shaft 18 through a shaft coupling between the gear side coupling recess 21 and the coupling shaft protrusion 20 at the center of the drum driving gear 22. Then, the coupling shaft concave portion 17 integrated with the coupling shaft convex portion 20 and the coupling shaft flange 19 interposed therebetween is engaged with the drum shaft convex portion 16 so that the driving force is transmitted to the process cartridge B. . In this way, the drum driving gear 22 and the drum shaft convex portion 16 in the process cartridge B rotate integrally.
[0054]
  Therefore, in the configuration of the present embodiment, when the process cartridge B is mounted on the apparatus main body 13 and the drum drive gear 22, the coupling shaft 18, and the drum shaft convex portion 16 are fitted and rotated, respectively, Since each ridge line of the drum shaft convex portion 16 of the triangular prism and the inner surface of the coupling shaft concave portion 17 and each ridge line of the coupling shaft convex portion 20 and the inner surface of the gear side coupling concave portion 21 are in contact with each other, the axial centers coincide with each other. Further, due to the twisted shape, a force acts in a direction in which the concave portions 17 and 21 pull the convex portions 16 and 20 closer together, and the end surface of the drum shaft convex portion 16 comes into contact with the bottom of the coupling shaft concave portion 17. So, drum shaftConvexThe photosensitive drum 7 integrated with the unit 16 is stably determined in the axial direction and the radial direction in the apparatus main body 13.
[0055]
In the present embodiment, as viewed from the photosensitive drum 7 side, the twisting direction of the drum shaft convex portion 16 is directed from the root of the drum shaft convex portion 16 to the tip with respect to the rotational direction of the photosensitive drum 7. The opposite direction, and the twisting direction of the coupling shaft recess 17 is the opposite direction inward from the entrance of the coupling shaft recess 17. Similarly, when viewed from the photosensitive drum 7 side, the twisting direction of the coupling shaft convex portion 20 is opposite to the rotation direction of the photosensitive drum 7 from the root of the coupling shaft convex portion 20 toward the tip. Further, the twisting direction of the gear side coupling recess 21 is opposite to the inside from the entrance of the gear side coupling recess 21.
[0056]
The device main body 13 is provided with a main body shaft coupling device. In this main body shaft coupling device, a coupling shaft concave portion 17 is disposed at a position coinciding with the rotational axis of the photosensitive drum 7 when the process cartridge B is inserted. As shown in FIG. 11, the coupling shaft 18 is a driving shaft that is further coupled to a drum driving gear 22 that transmits a driving force of a driving motor (not shown) to the photosensitive drum 7.
[0057]
{Shaft coupling attachment / detachment device}
Next, in connection with the closing operation of the opening / closing cover 14, the movement of the coupling shaft convex portion 20 with respect to the gear side coupling concave portion 21 and the configuration in which the coupling shaft concave portion 17 and the drum shaft convex portion 16 are fitted are shown in FIGS. This will be described with reference to FIG.
[0058]
10 and 11 are sectional views for explaining the apparatus main body 13, the process cartridge B, and the shaft coupling apparatus.
[0059]
A coupling bearing 27 is fitted and fixed to the main body frame 23 of the printer that forms the positioning portions of the process cartridge B and the drive system unit.
[0060]
A compression coil spring 26 is inserted and contracted on the root side of the caulking shaft 25, which is fastened to a drive metal plate 24 that is fixed and supported by a caulking fixed and supported drive shaft, and adjacent to the compression coil spring 26. A drive-side coupling shaft convex portion 20 formed in a columnar shape that is fitted with the caulking shaft 25 and slides in the thrust direction and is twisted with a substantially equilateral triangle in cross section on the drive metal plate 24 side. On the 7 side, a coupling shaft 18 having a coupling shaft recess hole 17a that fits and couples with the drum shaft protrusion 16 that is a projection of a triangular prism twisted in a substantially equilateral triangle is rotatably fitted. .
[0061]
A drive-side coupling shaft convex portion 20 that transmits a driving rotational force from a drive motor (not shown) to the photosensitive drum 7 and is formed in a columnar shape in which the section of the coupling shaft 18 is twisted with a substantially equilateral triangle at the center. The drum drive gear 22, which is a helical gear having a gear-side coupling recess 21 that slides and slides while twisting, is slidably in contact with the end face of the coupling bearing 27.
[0062]
The coupling bearing 27 has a flange portion 27 a that is fitted and fixed to the main body frame 23. The cylindrical outer periphery of the concave portion 17 of the coupling shaft 18 is formed at the center of the flange portion 27 a in the longitudinal direction of the photosensitive drum 7. When a radial bearing portion 27b that is relatively movable in the direction and is rotatable is disposed, and the radial bearing portion 27b passes through the main body frame 23 and engages with the drum shaft convex portion 16 I will guide you. A horizontal member 27c is provided in the axial direction so that at least the upper and lower parts are opened from the flange portion 27a, and a thrust bearing portion 27d that integrally supports the thrust surface of the drum drive gear 22 is integrally provided at the tip of the horizontal member 27c. . A cam lever 28 is inserted into the opening 27e between the horizontal members 27c from above.
[0063]
The cam lever 28 is a means for relatively moving the coupling shaft 18 in the longitudinal direction of the photosensitive drum 7. The cam lever 28 vertically penetrates the opening 27 e of the coupling bearing 27 and is provided in the center. The coupling shaft 18 passes through a round elongated hole portion 28b in a cam-shaped slope 28a having a vertical portion of a vertical portion 28c and a top portion 28d on the upper and lower sides. The cam lever 28 is configured such that the side surface of the flange 19 of the coupling shaft 18 urged toward the photosensitive drum 7 by the compression coil spring 26 is in contact with the slope 28a, the low portion 28c, and the top portion 28d. The side opposite to the side where the slope 28a is provided is a vertical surface 28e over the entire length of the upper and lower sides, and is slidably in contact with the flange portion 27a of the coupling bearing 27. Although not shown, the cam lever 28 is guided by a vertical guide fixed to the apparatus main body 13, and is provided with a pin 28f provided at the upper end and an opening / closing cover 14 pivotally attached to the apparatus main body 13 by a shaft 14a. The other end of a link (not shown) to which is pivoted is coupled. However, the cam lever 28 may be guided so as to be movable up and down between the horizontal members 27c.
[0064]
In the image forming apparatus A in which the detachable process cartridge B transmits the driving rotational force from the apparatus main body 13 by coupling coupling, a state where the shaft coupling before the process cartridge B is inserted is released will be described with reference to FIG. .
[0065]
The drum drive gear 22 is connected by a gear train (not shown) from a drive motor (not shown), and further connected from the drum drive gear 22 to a gear train (not shown) for paper feed and conveyance systems.
[0066]
The cam lever 28 moves up and down in conjunction with opening and closing of the opening and closing cover 14 that opens and closes the cartridge mounting portion of the process cartridge B of the apparatus main body 13.
[0067]
First, when the process cartridge B is mounted on the apparatus main body 13, the opening / closing cover 14 of the apparatus main body 13 is open, and the cam lever 28 between the coupling bearing flange portion 27 a and the coupling flange portion 19 is As shown in FIG. 10, the coupling shaft flange 19 is pushed in the direction in which the compression coil spring 26 is compressed at the top portion 28 d until the cam shape height is in the raised position.
[0068]
Therefore, at the position where the process cartridge B inside the apparatus main body 13 is positioned, the coupling shaft 18 is retracted to the drive side with respect to the main body frame 23 and does not interfere with the mounting of the process cartridge B.
[0069]
Second, as shown in FIG. 10, when the process cartridge B is mounted on the apparatus main body 13 and the process cartridge B is within the positioning position of the guide member 15 fixed to the main body frame 23, the opening / closing cover 14 can be closed. .
[0070]
When the opening / closing cover 14 is closed, the cam lever 28 between the coupling bearing flange portion 27a and the coupling flange portion 19 is pushed down as shown in FIG. 11, and the top portion 28d and its back portion are connected to the coupling shaft flange 19 and the cup. When the flange 28a of the ring bearing 27 slides and descends and the slope 28a comes into contact with the coupling shaft flange 19, the coupling shaft 18 moves toward the photosensitive drum 7 by the spring force of the compression coil spring 26. To do. The coupling shaft flange 19 advances to a low portion 28c having a low cam shape while sliding on a slope 28a connecting the cam shape height difference of the cam lever 28.
[0071]
For this reason, the coupling shaft concave portion 17 on the driving side is pressed against the drum shaft convex portion 16 of the process cartridge B mounted inside the apparatus main body 13.
[0072]
At this time, since the drum drive gear 22 meshes with a large number of gear trains (not shown) driving the roller shafts under load, the drum drive gear 22 does not rotate. The equilateral triangle slides while rotating along the concave hole 21 having a twisted shape.
[0073]
Therefore, the coupling shaft concave portion 17 and the drum shaft convex portion 16 are coupled. As shown in FIG. 11, the spacer portion 39 enters between the coupling shaft flange 19 and the thrust bearing portion 27d of the coupling bearing 27, and the thrust reaction force due to the torsion angle of each shaft or the reaction force due to driving rotation is applied to the coupling shaft. Even if 18 is operated in the direction of releasing the coupling, the coupling shaft 18 cannot move in the thrust direction due to the presence of the spacer portion 39, and the coupling of the shaft coupling cannot be removed.
[0074]
Since the shaft coupling is a combination of a twisted substantially equilateral triangular prism shaft and a hole, the concave portion 17 of the coupling shaft 18 pulls the drum shaft convex portion 16 in the axial direction by rotation. In this state, the shaft coupling in the drive transmission system of the process cartridge B and the apparatus main body 13 is coupled, and the drive transmission is possible.
[0075]
Third, the operation when the process cartridge B is taken out from the apparatus main body 13 by replacement of the process cartridge B, jamming (referred to as a paper jam), or the like will be described.
[0076]
In order to remove the process cartridge B from the apparatus main body 13, the coupling of the shaft coupling must be released.
[0077]
Since the concave portion 17 formed in the coupling shaft 18 is twisted in a direction in which the drum shaft convex portion 16 is pulled in the axial direction by driving rotation, the coupling of the shaft coupling is opposite to the driving rotational direction of the coupling shaft 18. If it is not rotated in the direction, the drum shaft convex portion 16 twisted into the concave portion 17 is not released.
[0078]
In the present invention, when the opening / closing cover 14 for the cartridge mounting portion is opened when extracting the process cartridge B, the cam lever 28 is pulled up in conjunction with the opening / closing cover 14, so that the axial direction of the flange portion 19 of the coupling shaft 18 is increased. The spacer portion 39 that has been controlled so that the coupling of the shaft coupling is not removed is also lifted out of the coupling bearing 27, so that the coupling shaft 18 can move in the thrust direction.
[0079]
When the cam lever 28 is further lifted, the cam portion 28A is lifted together. When the cam portion 28A is pulled up, the cam-shaped slope 28a has a lift from the bottom portion 28c to the top portion 28d, so that the coupling shaft flange 19 is pushed against the spring force of the compression coil spring 26 by the slope 28a. The coupling shaft 18 is pulled back to the drum drive gear 22 side, which is the direction in which the compression coil spring 26 is compressed.
[0080]
At this time, the drum drive gear 22 is supported in an axially stationary manner and meshes with a large number of gear trains (not shown) under load and does not rotate easily. The center of the drum drive gear 22 slides in the direction of the drive metal plate 24 while rotating in the reverse direction to the drive direction along the screw surface of the gear-side coupling recess hole 21 in which the substantially equilateral triangle of the drive gear 22 is twisted. Twist into. That is, since the coupling shaft 18 is twisted and retracted in the direction opposite to the driving rotation direction, the coupling of the shaft shaft convex portion 16 and the coupling shaft concave portion 17 is connected to the opening / closing cover 14. The process cartridge B is released only by opening, and the coupling shaft 18 is also retracted to a position retracted to the drive side from the main body frame 23. Therefore, the process cartridge B does not require any operation other than the operation in the direction perpendicular to the longitudinal direction. Can be taken out.
[0081]
According to this embodiment, the twist angle at the contact portion between the drum shaft convex portion 16 and the coupling shaft concave portion 17 and the twist angle at the contact portion between the coupling shaft convex portion 20 and the gear side coupling concave portion hole 21 are determined. If equal, when the shaft coupling is released, the resistance of the gear train connected to the drum drive gear 22 is large, and the rotational resistance of the photosensitive drum 7 and the resistance of the gear train connected to the helical gear 37a are large. However, since the coupling shaft 18 can be moved from the photosensitive drum 7 side to the driving metal plate 24 side while the drum driving gear 22 and the photosensitive drum 7 remain stationary, the load applied to the opening / closing cover 14 is small.
[0082]
Therefore, the twist angle of each screw surface in the drum shaft convex portion 16, the coupling shaft concave portion 17, the coupling shaft convex portion 20, and the gear side coupling concave portion hole 21 can be increased (the twist is strong). The fact that the twist angle can be increased greatly attracts the photosensitive drum 7 in the axial direction at the time of image formation, and the effect of making the axial position of the photosensitive drum 7 accurate is great.
[0083]
Furthermore, since the drum drive gear 22 does not move in the axial direction, the space occupied by the shaft coupling device in the apparatus main body 13 is small, which contributes to the miniaturization of the apparatus main body 13.
[0084]
[Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0085]
Note that the basic configurations of the process cartridge B and the electrophotographic image forming apparatus A are the same as those in the first embodiment described above, and therefore redundant description is omitted, and members having the same functions as those in the first embodiment are denoted by the same reference numerals. Is attached.
[0086]
FIG. 12 is a sectional view for explaining the apparatus main body 13, the process cartridge B, and the shaft coupling apparatus.
[0087]
The stepped caulking shaft 25 coaxially having two large and small diameters crimped to the drive metal plate 24 is fitted with a large-diameter round hole 18c formed in the coupling shaft 18 at a large-diameter shaft portion 25a. Further, the small diameter shaft portion 25b of the stepped caulking shaft 25 has a small diameter round hole formed closer to the photosensitive drum 7 than the large diameter round hole 18c formed inside the coupling shaft 18. 18d, and the coupling shaft 18 is positioned in the XY direction (perpendicular to the axis) in a long range from the large diameter shaft portion 25a to the small diameter shaft portion 25b of the stepped caulking shaft 25. It is positioned.
[0088]
A compression coil spring 26 that urges the coupling shaft 18 toward the photosensitive drum 7 is inserted into the small diameter shaft portion 25b of the stepped caulking shaft 25, and one end of the compression coil spring 26 is inserted into the stepped crimping shaft 25. The other end portion of the compression coil spring 26 is formed inside the coupling shaft 18 and abuts against a stepped portion 25c which is a boundary surface between the small diameter shaft portion 25b and the large diameter shaft portion 25a of the attached crimping shaft 25. Further, it is configured to be contracted in contact with the flange portion 18b in the thrust direction.
[0089]
The drum-side round shaft 18e of the coupling shaft 18 coaxial with the large-diameter round hole 18c and the small-diameter round hole 18d formed inside the coupling shaft 18 is a radial bearing portion 27b of the coupling bearing 27. And fitted.
[0090]
Furthermore, the shaft portion 27 f of the coupling bearing 27 that is coaxial with the radial bearing portion 27 b of the coupling bearing 27 is fitted and attached to the positioning reference hole 23 a of the main body frame 23.
[0091]
Therefore, the drive sheet metal 24 and the main body frame 23 are fitted and positioned at the shaft center of each shaft coupling member.
[0092]
Further, by fitting other caulking shafts (not shown) crimped to the drive metal plate 24 into round elongated holes (not shown) provided at other positions of the main body frame 23, the shaft center of the caulking shaft 25 is obtained. Positioning in the rotational direction centered on.
[0093]
As described above, when the drive metal plate 24 with the caulking shaft (not shown), which is the rotation shaft of the gear train (not shown), is attached and fixed to the main body frame 23, By using the stepped caulking shaft 25 as the positioning reference on the XY plane with respect to the drive metal plate 24, the drive system can be accurately positioned using the shaft coupling device as a reference.
[0094]
Here, when the opening / closing cover 14 is closed, the cam lever 28 is lowered, and at the same time, the spacer portion 39 enters between the flange 19 and the thrust bearing portion 27d as shown in FIG. 13, so that the coupling shaft 18 cannot be retracted. .
[0095]
[Embodiment 3]
Next, another embodiment 3 of the shaft coupling device which is a drive transmission mechanism for transmitting drive from the electrophotographic image forming apparatus to the process cartridge B will be described.
[0096]
The description of the same components as in the first embodiment is omitted in the third embodiment. In the third embodiment, members having the same functions as those in the first embodiment have the same reference numerals.
[0097]
{Shaft coupling device}
In conjunction with the closing operation of the opening / closing cover 14 in the third embodiment, the coupling shaft convex portion 20 is moved with respect to the drum driving gear side coupling concave portion 21 and the coupling shaft concave portion 17 and the drum shaft convex portion 16 are fitted. The configuration will be described with reference to FIGS. 14 to 18.
[0098]
  The cam lever 28 is mounted on the process cartridge B in the direction perpendicular to the moving direction of the coupling shaft 18.Open and closeIt is coupled with the opening / closing cover 14 and moves up and down in conjunction with the opening / closing of the opening / closing cover 14. When the opening / closing cover 14 is closed, it moves downward and simultaneously pushes down the cam portion 28A. When the opening / closing cover 14 is opened, it moves upward. Simultaneously with the movement, the coupling spacer 29 and the cam portion 28A are pulled up.
[0099]
A cam portion 28A having a slope 28a, a low portion 28c, and a top portion 28d is means for relatively moving the coupling shaft 18 in the longitudinal direction of the photosensitive drum 7, and is provided in the center through the coupling bearing 27. The coupling shaft 18 passes through a round slot 28b having cam-shaped slopes 28a on both sides. The flange 19 of the coupling shaft 18 urged toward the photosensitive drum 7 by the compression coil spring 26 serves as a sliding portion, and the sliding of the coupling shaft 18 so that the cam portion 28A acts on the flange 19 when moving up and down. The configuration having the cam lever 28 that can move up and down in the direction perpendicular to the moving direction is the same as in the first embodiment.
[0100]
The coupling spacer 29 holds the cam lever 28 and can slide up and down with respect to the cam lever 28. The coupling spacer 29 is configured such that the coupling shaft 18 slides with the cam-shaped slopes 28a on both sides of the round elongated hole 28b of the cam lever 28 and the coupling shaft 18 moves backward after the drum shaft convex portion 16 and the coupling shaft concave portion 17 are coupled. The coupling spacer 29 is biased downward by the stopper spring 31 so that the coupling spacer 29 can enter between the flange portion 19 of the coupling shaft 18 and the thrust bearing portion 27d of the coupling bearing 27 so as not to be detached from the drum shaft convex portion 16. ing.
[0101]
  The coupling spacer 29 has a bifurcated portion 29d at the lower portion, and has a width between the bifurcated portion 29d so that the outer periphery of the coupling shaft convex portion 20 of the coupling shaft 18 is just inserted. The outer rectangle of the bifurcated portion 29d is a coupling bearing. The surface of the coupling bearing 27 that is in contact with the thrust bearing portion 27d is a single plane in the vertical direction, and the lower end on the plane side is an edge 29e. Further, as shown in FIG. 18, the coupling spacer 29 has a slide portion 29 b that has a guide portion 28 h in the vertical direction of the cam lever 28 and is slidable in the vertical direction.
[0102]
The stopper spring 31 continuously urges the coupling spacer 29 toward the coupling shaft 18 (downward) with respect to the cam lever 28 at all times. The stopper spring 31 is a compression coil spring and is disposed in a vertical rectangular long hole 28g (see FIGS. 14 and 18) provided in the cam lever 28. The upper side 28i of the rectangular long hole 28g is connected to one spring. As shown in FIG. 18, a protrusion 29a provided on the coupling spacer 29 and projecting into the rectangular long hole 28g is used as the other spring seat. The stopper spring 31 is contracted and inserted into the rectangular elongated hole 28g, and the protrusion 29a is in pressure contact with the lower side 28j of the rectangular elongated hole 28g. In the image forming apparatus A in which the detachable process cartridge B transmits the driving rotational force from the apparatus main body 13 through the shaft joint, a state where the shaft joint before the process cartridge B is inserted is released will be described with reference to FIG. .
[0103]
The drum drive gear 22 is connected by a gear train (not shown) from a drive motor (not shown), and further connected from the drum drive gear 22 to a gear train (not shown) for paper feed and conveyance systems.
[0104]
The cam lever 28 moves up and down in conjunction with opening and closing of the opening / closing cover 14 on the side of the apparatus main body 13 for attaching / detaching the process cartridge B.
[0105]
First, when the process cartridge B is mounted on the apparatus main body 13, the opening / closing cover 14 of the apparatus main body 13 is in an open state, and the cam located between the flange portion 27 a of the coupling bearing 27 and the coupling shaft flange 19. As shown in FIG. 15, the portion 28 </ b> A pushes the flange 19 of the coupling shaft 18 in the direction of compressing the compression coil spring 26 to the top portion 28 d where the cam shape height is high by raising the cam lever 28.
[0106]
Therefore, at the position where the process cartridge B inside the apparatus main body 13 is positioned, the coupling shaft 18 is retracted to the drum drive gear 22 side from the main body frame 23 and does not interfere with the process cartridge B mounting.
[0107]
Secondly, when the process cartridge B is mounted on the apparatus main body 13 and the process cartridge B is in the positioning position formed by the main body frame 23, the opening / closing cover 14 can be closed.
[0108]
When the opening / closing cover 14 is closed, the cam portion 28A located between the coupling bearing 27 and the coupling shaft flange 19 is lowered and pushed down as shown in FIG. The 18 flanges 19 move toward the drum shaft convex portion 16 to the range of the low portion 28c having the low cam shape height while sliding with the slope 28a connecting the cam shape height difference of the cam portion 28A.
[0109]
For this reason, the coupling shaft concave portion 17 on the driving side is pressed against the drum shaft convex portion 16 of the process cartridge B mounted inside the apparatus main body 13.
[0110]
At this time, since the drum drive gear 22 meshes with a large number of gear trains (not shown) driving the roller shafts under load, the drum drive gear 22 does not rotate. The equilateral triangle moves in the axial direction while being rotated by the gear side coupling recess hole 21 having a twisted shape.
[0111]
Here, since the drum shaft convex portion 16 and the coupling shaft concave portion 17a have a substantially equilateral triangular entrance shape, the coupling shaft concave portion 17 is formed on the drum shaft convex portion 16 by the phase difference as shown in FIG. There is a case where the shaft end faces come into contact without meshing.
[0112]
As shown in the figure, when the cam lever 28 is pushed down, the cam portion 28A of the coupling shaft 18 is lowered to the range of the low portion 28c where the height of the cam shape is low, but the drum shaft convex portion 16 and the coupling shaft concave portion 17 are lowered. Does not bite. At this time, since the coupling spacer 29 urged by the stopper spring 31 does not come into contact with the outer periphery of the flange 19 of the coupling shaft 18 and cannot be lowered, the stopper spring 31 compressed by the lowering of the cam lever 28 continues to press the flange 19. However, the cam portion 28A and the cam lever 28 are moved to a fixed position in the door closed state, and the position of the cam lever 28 is fixed at a fixed position at the lower limit.
[0113]
When the drum drive gear 22 is driven for image output, the coupling shaft 18 biased toward the photosensitive drum 7 by the compression coil spring 26 is pressed against the drum shaft convex portion 16. When the phases of the substantially equilateral triangles match each other, the coupling shaft concave portion 17 is coupled with the drum shaft convex portion 16, and when the coupling shaft 18 moves in the direction of the photosensitive drum 7, the flange 19 is pointed downward. Detach from the ring spacer 29. Then, the coupling spacer 29 that urges the flange 19 enters between the flange 19 and the thrust bearing portion 27d of the coupling bearing 27 by the spring force of the stopper spring 31 as shown in FIG. Even if a thrust reaction force or a reaction force due to driving rotation acts in a direction to remove the coupling with the drum shaft convex portion 16 with respect to the coupling shaft 18, the coupling shaft 18 is moved in the axial direction by the presence of the coupling spacer 29. The shaft coupling cannot be removed.
[0114]
In this state, the shaft coupling between the process cartridge B and the drive transmission system of the apparatus main body 13 is coupled, and the drive transmission is possible.
[0115]
Since the shaft coupling is a combination of a twisted substantially equilateral triangular shaft and a hole, the concave hole 17a of the coupling shaft 18 twists in the direction in which the drum shaft convex portion 16 is pulled in the axial direction by rotation, so that the drum shaft has the concave hole 17a. Invited to.
[0116]
Third, the operation when the process cartridge B is taken out from the apparatus main body 13 by replacement of the process cartridge B or jam processing will be described.
[0117]
In order to remove the process cartridge B from the apparatus main body 13, the coupling of the shaft coupling must be released. The drum drive gear 22 on the apparatus main body 13 side and the photosensitive drum 7 of the process cartridge B are connected to loads by gear trains, respectively, and a concave hole 17a formed in the coupling shaft 18 drives the drum shaft convex portion 16 by driving rotation. Since the shaft coupling is twisted in the direction of pulling in the axial direction, the coupling of the shaft joint is twisted into the recess hole 17a of the coupling shaft recess 17 unless the coupling shaft 18 is rotated in the direction opposite to the driving rotation direction. The coupling between the drum shaft convex portion 16 and the coupling shaft concave portion 17 is not released.
[0118]
In the present invention, when the opening / closing cover 14 for opening and closing the mounting portion of the process cartridge B is opened when the process cartridge B is extracted, the cam lever 28 is pulled up in conjunction with the opening. When the lower side 28j of the rectangular long hole 28g of the cam lever 28 shown in FIG. 18 hits the protrusion 29a of the coupling spacer 29, the thrust direction of the flange 19 of the coupling shaft 18 is restricted so that the coupling of the shaft coupling does not come off. The coupling spacer 29 is pulled up together with the cam lever 28 so that the coupling shaft 18 can move in the axial direction.
[0119]
When the cam lever 28 is further lifted, the cam portion 28A is then lifted, whereby the coupling shaft 18 moves toward the drum drive gear 22 which is the direction in which the compression coil spring 26 is compressed along the slope 28a. Pulled back.
[0120]
At this time, the drum driving gear 22 meshes with a large number of gear trains (not shown) under load and does not rotate easily. Therefore, the coupling shaft 18 has a shape in which a substantially equilateral triangle of the drum driving gear 22 is twisted. While rotating in the direction opposite to the drive direction along the twist direction of the recess hole 21, it slides in the direction of the drive sheet metal 24 and twists into the drum drive gear 22.
[0121]
That is, since the coupling shaft 18 is twisted and retracted in the direction opposite to the driving rotation direction, the coupling of the shaft joint between the drum shaft convex portion 16 and the coupling shaft concave portion 17a only opens the opening / closing cover 14. The coupling shaft 18 is also retracted to the position retracted to the drive side from the main body frame 23, so that the process cartridge B can be taken out without requiring any other operation.
[0122]
[Embodiment 4]
Next, another embodiment 4 of the shaft coupling device which is a drive transmission mechanism for transmitting drive from the electrophotographic image forming apparatus to the process cartridge B will be described.
[0123]
The description of the same components as those in the first embodiment or the third embodiment is omitted in the fourth embodiment. Moreover, in this Embodiment 4, the member which has the same function as Embodiment 1 or Embodiment 3 shows the same code | symbol.
[0124]
{Shaft coupling device}
Next, in connection with the closing operation of the opening / closing cover 14, the movement of the coupling shaft convex portion 20 with respect to the drum driving gear side coupling concave portion 21 and the configuration in which the coupling shaft concave portion 17 and the drum shaft convex portion 16 are fitted to each other are illustrated. This will be described with reference to FIGS.
[0125]
In the perspective view of FIG. 19, the cam lever 28 is a means for moving the coupling shaft 18 relatively in the longitudinal direction of the photosensitive drum 7. The cam lever 28 passes through the coupling bearing 27, and the coupling shaft 18 passes through a round elongated hole 28b having cam-shaped slopes 28a on both sides. The coupling shaft 18 is urged toward the photosensitive drum 7 by the compression coil spring 26. The cam lever 28 can move up and down in the direction perpendicular to the moving direction of the coupling shaft 18 with the flange 19 of the coupling shaft 18 and the thrust bearing portion 27d of the coupling bearing 27 as sliding portions.
[0126]
As shown in FIG. 24, the coupling spacer 29 has a slide portion 29 b that holds the guide portion 28 h of the cam lever 28 and is slidable in the vertical direction with respect to the cam lever 28. As shown in FIG. 19, the coupling shaft 18 that slides on the cam-shaped slopes 28a on both sides of the round elongated hole portion 28b of the cam lever 28 is moved backward after the drum shaft convex portion 16 and the coupling shaft concave portion 17 are coupled. Then, it is biased downward by the stopper spring 31 so that it can enter between the flange 19 of the coupling shaft 18 and the thrust bearing portion 27d of the coupling bearing 27 so as not to be disengaged from the drum shaft convex portion 16. It serves as a stopper for preventing the coupling shaft 18 from coming off. A coupling lever 30 is sandwiched between the coupling spacer 29 and the cam lever 28, and each is coupled to be slidable in the vertical direction. As shown in FIG. 25, the coupling lever 30 is above the direction perpendicular to the moving direction of the coupling shaft 18, and the opening / closing cover 14 which is an attachment / detachment opening of the process cartridge B is coupled to the upper end pin 30a. In association with opening and closing of the cover 14, the cam lever 28 slides up and down. A sliding portion 33 into which the coupling lever 30 is fitted is provided at the upper portion of the cam lever 28, and the lower portion of the sliding portion 33 is widened and protrudes to the left and right at the lower end of the coupling lever 30. A stopper portion 33a into which 30b is fitted is provided, and upper and lower abutting portions 33b and 33c with which the claw portion 30b abuts when the coupling lever 30 moves up and down are provided.
[0127]
The coupling lever 30 is provided with a rectangular long hole 28g that is long in the vertical direction, and a stopper spring 31 is accommodated in the rectangular long hole 28g. The relationship between the rectangular elongated hole 28g, the coupling spacer 29, and the stopper spring 31 is the same as the coupling relationship between the cam lever 28 and the coupling spacer 29 of the third embodiment, and the description of the third embodiment is adopted.
[0128]
The cam lever 28, the coupling spacer 29, the coupling lever 30, and the stopper spring 31 are unitized as shown in FIG. 20 for easy assembly.
[0129]
In the image forming apparatus A in which the detachable process cartridge B transmits the driving rotational force from the apparatus main body 13 by the coupling of the shaft coupling, a state where the shaft coupling before the process cartridge B is inserted is released with reference to FIG. To do.
[0130]
The drum drive gear 22 is connected by a gear train (not shown) from a drive motor (not shown), and further connected from the drum drive gear 22 to a gear train (not shown) for paper feed and conveyance systems.
[0131]
The coupling lever 30 moves up and down in conjunction with opening and closing of the apparatus main body 13 side opening / closing cover 14 for attaching / detaching the process cartridge B.
[0132]
First, when the process cartridge B is mounted on the apparatus main body 13, the opening / closing cover 14 of the apparatus main body 13 is in an open state as shown in FIG. 25, and the pin 30 a of the coupling lever 30 is attached together with the opening / closing cover 14. The claw portion 30b of the coupling lever 30 comes into contact with the upper abutting portion 33b of the cam lever 28 so that the cam lever 28 is pulled up most, and the projection 29a of the coupling spacer 29 is moved to the rectangular elongated hole 28g by the stopper spring 31. The coupling spacer 29 is at the lowest position relative to the coupling lever 30. Further, the cam lever 28 between the coupling bearing flange portion 27a and the coupling shaft flange 19 is pulled up by the coupling lever 30 as shown in FIG. 21, and the coupling shaft 18 reaches the range of the top portion 28d where the cam shape height is high. The flange 19 pushes up the compression coil spring 26 in the compressing direction.
[0133]
Therefore, at the position where the process cartridge B inside the apparatus main body 13 is positioned, the coupling shaft 18 is retracted to the drum drive gear 22 side from the main body frame 23 and does not interfere with the process cartridge B mounting.
[0134]
Secondly, when the process cartridge B is mounted on the apparatus main body 13 and the process cartridge B is in the positioning position formed by the main body frame 23, the opening / closing cover 14 can be closed.
[0135]
When the opening / closing cover 14 is closed, the cam lever 28 between the coupling bearing flange portion 27a and the coupling shaft flange 19 causes the claw portion 30b of the coupling lever 30 shown in FIG. Due to the spring force of the coil spring 26, the flange 19 of the coupling shaft 18 slides on the slope 28a connecting the cam shape height difference of the cam lever 28, and the drum shaft protrudes in the axial direction up to the low portion 28c range where the cam shape height is low. It moves toward the part 16.
[0136]
For this reason, the coupling shaft concave portion 17 on the driving side is pressed against the drum shaft convex portion 16 of the process cartridge B mounted inside the apparatus main body 13.
[0137]
At this time, since the drum drive gear 22 meshes with a large number of gear trains (not shown) driving the roller shafts under load, the drum drive gear 22 does not rotate. The equilateral triangle moves in the axial direction while rotating along the concave hole 21 having a twisted shape.
[0138]
Here, since the drum shaft convex part 16 and the coupling shaft side concave hole 17 have a substantially equilateral triangular inlet shape, there is a case where the shaft coupling does not mesh with each other as shown in FIG.
[0139]
As shown in the figure, the cam lever 28 slides to the range of the low portion 28c where the cam-shaped height is low by being pushed down by the coupling lever 30, but the drum shaft convex portion 16 and the coupling shaft concave portion 17 are not engaged with each other. The low portion 28c of the cam portion 28A of the cam lever 28 and the flange 19 of the coupling shaft 18 are open. At this time, the coupling spacer 29 urged by the stopper spring 31 continues to urge the flange 19 of the coupling shaft 18, but the cam lever 28 and the coupling lever 30 slide to a fixed position in the door closed state. The position is fixed. When the drum drive gear 22 is driven for image output, the coupling shaft 18 biased toward the photosensitive drum 7 by the compression coil spring 26 is pressed toward the drum shaft convex portion 16. When the phases of the substantially equilateral triangles match each other, the coupling shaft 18 moves forward, the coupling shaft concave portion 17 is fitted to the drum shaft convex portion 16, and the shaft coupling is coupled.
[0140]
Then, the coupling spacer 29 urging the flange 19 downward enters between the flange 19 and the thrust bearing portion 27d of the coupling bearing 27 as shown in FIG. 23, and the thrust reaction force due to the twist angle of each shaft, Alternatively, even if the reaction force due to the drive rotation works in the direction in which the coupling shaft 18 is disconnected from the drum shaft convex portion 16, the coupling shaft 18 does not move in the axial direction due to the coupling spacer 29, so The bond does not come off.
[0141]
In this state, the shaft coupling between the process cartridge B and the drive transmission system of the apparatus main body 13 is coupled, and the drive transmission is possible.
[0142]
Since the shaft coupling is a combination of a twisted substantially equilateral triangular shaft and a hole, the concave portion 17a of the coupling shaft 18 twists the convex portion 16 of the drum shaft in a direction that pulls in by rotation, and the shaft is drawn into the hole.
[0143]
Third, the operation when the process cartridge B is taken out from the apparatus main body 13 by process cartridge B replacement, jam processing, or the like will be described.
[0144]
In order to remove the process cartridge B from the apparatus main body 13, the coupling of the shaft coupling must be released.
[0145]
Since the concave hole 17a formed in the coupling shaft 18 is twisted in a direction in which the drum shaft convex portion 16 is pulled by rotation by driving rotation, the coupling of the shaft coupling is opposite to the driving rotation direction of the coupling shaft 18. If it is not rotated in the direction, the drum shaft convex part 16 twisted into the concave hole 17a is not released.
[0146]
In the present invention, when the opening / closing cover 14 for opening and closing the mounting portion of the process cartridge B is opened when the process cartridge B is extracted, the coupling lever 30 slides on the sliding portion 33 of the cam lever 28 in conjunction with each other as shown in FIG. 24, the lower side 28j of the rectangular elongated hole 28g of the coupling lever 30 shown in FIG. 24 hits the protrusion 29a of the coupling spacer 29, and the coupling spacer 29 is pulled up. For this reason, the coupling spacer 29 that restricts the axial direction of the flange 19 of the coupling shaft 18 so as not to disengage the coupling of the shaft joint leaves the coupling bearing 27, and the coupling shaft 18 can move in the axial direction. It becomes like this.
[0147]
When the coupling lever 30 is further lifted, the claw portion 30b of the coupling lever 30 then hits the upper abutting portion 33b of the cam lever 28 and lifts the cam lever 28. When the cam lever 28 is pulled up, the coupling shaft flange 19 retracts along the slope 28a of the cam-shaped portion of the cam lever 28, and the coupling shaft 18 compresses the compression coil spring 26, which is the drum drive gear 22 side. Pulled back to.
[0148]
At this time, the drum drive gear 22 meshes with a large number of loaded gear trains (not shown) and does not rotate easily. Therefore, the coupling shaft 18 is a concave portion in which the substantially equilateral triangle of the drum drive gear 22 is twisted. The hole 21 moves in the direction of the drive metal plate 24 while rotating in the direction opposite to the drive direction along the twist rotation direction of the hole 21 and is twisted into the drum drive gear 22.
[0149]
That is, since the coupling shaft 18 is twisted and retracted in the direction opposite to the driving rotation direction, the coupling of the drum shaft convex portion 16 and the coupling shaft concave portion 17a only opens the opening / closing cover 14. The coupling shaft 18 is also retracted to the position retracted to the drive side from the main body frame 23, so that the process cartridge B can be taken out without requiring any other operation.
[0150]
In the embodiment, the coupling shaft and the drum shaft are engaged with each other by providing a drum shaft convex portion 16 on the photosensitive drum side and a concave portion 17 on the coupling shaft side, and the concave and convex portions 16 and 17 are engaged and disengaged. However, if the twist angle and the twist direction are the same, a twisted hole having a polygonal cross section is provided in the shaft coupling member on the photosensitive drum side, and a twisted polygonal column engaging and disengaging with the hole is provided in the coupling shaft 18. May be.
[0151]
The twisted hole provided at the center of the drum drive gear 22 and the twisted shaft end of the coupling convex portion 20 do not have to be polygonal in section, and may be a screw pair, a spiral spline, or the like. It is also possible to reverse the relationship between the hole and the shaft and to have a shaft having a twisted shape at the center of the drum drive gear 22 and to engage the shaft with a hole having a twisted shape of the coupling shaft.
[0152]
In the above embodiment, the compression coil spring is used to urge the coupling shaft 18 in the axial direction. However, if it is a compression spring, for example, a plurality of disc springs may be overlapped in the axial direction.
[0153]
【Example】
This is also shown in the embodiment.
[0154]
AlsoExampleAccording to the present invention, since the shaft coupling is constituted by the twisted hole having a polygonal cross section and the twisted polygonal column, the rotation accuracy of the drive transmission can be improved, so that the rotation accuracy of the electrophotographic photosensitive drum is improved. I was able to.
[0155]
    AlsoExampleAccording to this, the driving force can be reliably transmitted from the apparatus main body to the electrophotographic photosensitive drum.
[0156]
    AlsoExampleAccording to the present invention, when the driving force is transmitted (during image formation), the rotation center of the shaft coupling member provided in the apparatus main body and the rotation center of the shaft coupling member provided in the electrophotographic photosensitive drum are determined. I was able to match.
[0157]
    AlsoExampleAccording to the invention, when driving force is transmitted (when an image is formed), the positioning accuracy of the electrophotographic photosensitive drum and further the process cartridge relative to the apparatus main body is improved by pulling the electrophotographic photosensitive drum toward the apparatus main body. I was able to.
[0158]
    AlsoExampleWhen the drive transmission is not performed (when the open / close cover is opened in non-image formation), the connection of the shaft coupling between the image forming apparatus main body and the process cartridge is cut off, thereby the process cartridge The operability of taking out the image forming apparatus from the image forming apparatus main body could be improved.
[0159]
Since the coupling shaft having a small diameter moves in the thrust direction, there is no space for moving the rotating body, for example, a large gear, so that the size of the image forming apparatus main body becomes compact.
[0160]
In addition, after the coupling of the shaft coupling, by restricting the movement of the coupling shaft in the thrust direction by the coupling spacer, it is possible to transmit a reliable driving torque without the coupling being disengaged.
[0161]
Further, by further disposing the spring for urging the shaft coupling member in the coupling shaft, further downsizing of the device is realized. In addition, when removing the process cartridge, that is, when releasing the shaft coupling, the drive gear on the image forming apparatus main body side does not rotate, so that a large load is not received, and the operability is improved.
[0162]
Further, since the moving means of the coupling shaft is configured within the moving area of the coupling shaft, it is not necessary to arrange a space in the axial direction for the moving means, and the size of the image forming apparatus main body is compact. Become. The longitudinal direction of the image forming apparatus main body is reduced.
[0163]
Further, since the thrust receiving member for positioning the thrust direction of the rotating body and the radial bearing member of the coupling shaft are integrated, assembly productivity is improved.
[0164]
In addition, since a mechanism for releasing the power transmission device is not required when releasing the shaft coupling, the number of parts can be reduced and productivity can be improved.
[0165]
Further, it is possible to directly connect a plurality of gear trains to this rotating body, the number of gears can be reduced as a whole, and downsizing and cost reduction of the apparatus can be achieved.
[0166]
  In addition, since the center of the coupling shaft coincides with the center of the electrophotographic photosensitive drum, the positioning accuracy of the unit can be improved when the power transmission device on the image forming apparatus main body is unitized.
【The invention's effect】
  As explained above, according to the present invention,When transmitting the driving force from the driving source (when forming an image), the electrophotographic photosensitive drum is further pulled toward the apparatus main body of the electrophotographic image forming apparatus, so that the electrophotographic photosensitive drum and further the process cartridge are The positioning accuracy with respect to the main body could be improved. Further, when removing the process cartridge from the apparatus main body, the rotating body provided in the electrophotographic image forming apparatus is not rotated, so that the operability is improved without receiving a large load.
[Brief description of the drawings]
Each of the drawings shows an embodiment of the present invention.
FIG. 1 is a longitudinal sectional view illustrating an electrophotographic image forming apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a longitudinal sectional view of a process cartridge.
FIG. 3 is a perspective view seen from the upper right as viewed in the mounting direction of the process cartridge.
FIG. 4 is a perspective view seen from the upper left as viewed in the mounting direction of the process cartridge.
FIG. 5 is a perspective view of the left side of the cartridge mounting portion.
FIG. 6 is a right perspective view of a cartridge mounting portion.
FIG. 7 is a longitudinal sectional view of a photosensitive drum.
FIG. 8 is a perspective view of a shaft coupling.
FIG. 9 is a perspective view illustrating a shaft coupling device with a process cartridge of the electrophotographic image forming apparatus according to the first embodiment.
10 is a longitudinal sectional view for explaining the separation of the shaft coupling from the process cartridge of the electrophotographic image forming apparatus according to Embodiment 1. FIG.
FIG. 11 is a longitudinal sectional view for explaining the coupling of the shaft coupling with the process cartridge of the electrophotographic image forming apparatus according to the first embodiment.
FIG. 12 is a horizontal sectional view for explaining a shaft coupling device with a process cartridge of an electrophotographic image forming apparatus according to Embodiment 2 of the present invention.
13 is a horizontal cross-sectional view showing the operation when the shaft coupling is connected in FIG. 12. FIG.
FIG. 14 is an exploded perspective view of the third embodiment.
FIG. 15 is a longitudinal sectional view of the third embodiment.
FIG. 16 is a longitudinal sectional view of the third embodiment.
FIG. 17 is a longitudinal sectional view of the third embodiment.
FIG. 18 is an exploded perspective view of a main part of the third embodiment.
FIG. 19 is an exploded perspective view of the fourth embodiment.
FIG. 20 is a perspective view of a main part of the fourth embodiment.
FIG. 21 is a longitudinal sectional view of the fourth embodiment.
FIG. 22 is a longitudinal sectional view of the fourth embodiment.
FIG. 23 is a longitudinal sectional view of the fourth embodiment.
24 is an exploded perspective view of main parts in Embodiment 4. FIG.
FIG. 25 is a longitudinal sectional view of the entire device showing an interlocking portion between an opening / closing cover and a shaft coupling device in a fourth embodiment.
[Explanation of symbols]
A: Image forming apparatus
B ... Process cartridge
1 ... Optical system
2 ... Recording medium
DESCRIPTION OF SYMBOLS 3 ... Conveyance means 3a ... Paper feed cassette 3b ... Pickup roller 3d ... Conveyance roller pair 3f ... Guide plate 3g ... Discharge roller pair
4 ... Transfer means
5 ... Fixing means 5a ... Drive roller 5b ... Heater 5c ... Fixing rotation zone
6 ... discharge section
7 ... photosensitive drum 7a ... drum cylinder 7b ... photosensitive layer
8 ... Charging roller
9 ... exposure aperture
DESCRIPTION OF SYMBOLS 10 ... Developing means 10a ... Toner storage part 10b ... Toner feeding member 10c ... Fixed magnet 10d ... Developing roller 10e ... Developing blade
DESCRIPTION OF SYMBOLS 11 ... Cleaning means 11a ... Cleaning blade 11b ... Squee sheet 11c ... Waste toner reservoir
12a ... toner frame 12b ... developing frame 12c ... cleaning frame 12c1 ... contact part 12c2 ... bearings 12c4, 12c5 ... mounting guide
13 ... Main body 13a ... Abutting part
14 ... Opening / closing cover 14a ... Shaft 14b ... Compression coil spring
15 ... Coupling convex shaft
16 ... Drum shaft convex part
17 ... Coupling shaft recess 17a ... Recess hole
18 ... Coupling shaft 18a ... Hole 18b ... Flange 18c ... Large diameter round hole 18d ... Small diameter round hole 18e ... Drum side round shaft
19 ... Coupling shaft flange
20 ... Coupling shaft convex part
21 ... Gear side coupling recess hole
22 ... Drum drive gear
23 ... Body frame 23a ... Positioning reference hole
24 ... Drive metal plate
25 ... Caulking shaft 25a ... Large diameter shaft portion 25b ... Small diameter shaft portion 25c ... Stepped portion
26 ... Compression coil spring
27 ... Coupling bearing 27a ... Flange 27b ... Radial bearing 27c ... Horizontal member 27d ... Thrust bearing 27e ... Opening 27f ... Shaft
28 ... Cam lever 28A ... Cam part 28a ... Slope 28b ... Round long hole part 28c ... Low part 28d ... Top part 28e ... Vertical surface 28f ... Pin 28g ... Rectangular long hole 28h ... Guide part 28i ... Upper side 28j ... Lower side
29 ... Coupling spacer 29a ... Projection part 29b ... Slide part 29d ... Fork part 29e ... Edge
30 ... Coupling spacer 30a ... Pin 30b ... Claw
31 ... Stopper spring
33 ... Sliding part 33a ... Stopper part 33b, 33c ... Abutting part
34 ... Bearing 34a ... Boss 34b ... End face
35 ... Cartridge mounting guide member 35a, 35c ... Guide portion 35b, 35d ... U groove
36 ... Drum flange 36a ... Drum shaft 36b ... Spur gear 36c ... End face
37 ... Drum flange 37a ... Helical gear 37b ... Fitting part 37c ... End face
39 ... Spacer part

Claims (8)

In an electrophotographic image forming apparatus for detaching a process cartridge and forming an image on a recording medium,
a. An electrophotographic photosensitive drum;
Process means acting on the electrophotographic photosensitive drum;
Twist polygonal column protrusions provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
A cartridge mounting portion for detachably mounting a process cartridge having
b. A rotating body that is connected to the driving source and has a twisted hole with a polygonal cross section at the center, and is supported so as to be rotatable and not move in the axial direction;
c. A twisted polygonal column fitted in a twisted hole of the rotating body is provided at one end, and a twist angle and a twist direction which are engaged with and disengaged from a protrusion of the electrophotographic photosensitive drum at the other end are twisted at the one end. A coupling shaft that is the same as a polygonal column and has a twisted hole with a polygonal cross section, and is supported rotatably and axially movable.
d. A spring member for biasing the coupling shaft in the direction of said electrophotographic photosensitive drum,
e. Longitudinal twisting and position disengaged with the protrusions of the polygonal column was provided at one end, twisted hole said electrophotographic photosensitive member of the coupling shaft of the twisted hole the electrophotographic photosensitive drum of said coupling shaft An axially moving means of the coupling shaft provided so as to take a position engaging with a twisted polygonal column protrusion provided at one end in the longitudinal direction of the drum;
f. Conveying means for conveying the recording medium;
g. A spacer member to be inserted into the space created by sliding in the axial direction to the coupling shaft is coupled with said electrophotographic photosensitive drum,
An electrophotographic image forming apparatus comprising: In an electrophotographic image forming apparatus for detaching a process cartridge and forming an image on a recording medium,
a. An electrophotographic photosensitive drum;
Process means acting on the electrophotographic photosensitive drum;
Twist polygonal column protrusions provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
A cartridge mounting portion for detachably mounting a process cartridge having
b. A rotating body that is connected to the driving source and has a twisted hole with a polygonal cross section at the center, and is supported so as to be rotatable and not move in the axial direction;
c. A twisted polygonal column fitted in a twisted hole of the rotating body is provided at one end, and a twist angle and a twist direction which are engaged with and disengaged from a protrusion of the electrophotographic photosensitive drum at the other end are twisted at the one end. A coupling shaft that is the same as a polygonal column and has a twisted hole with a polygonal cross section, and is supported rotatably and axially movable.
d. A spring member for biasing the coupling shaft in the direction of said electrophotographic photosensitive drum,
e. Longitudinal twisting and position disengaged with the protrusions of the polygonal column was provided at one end, twisted hole said electrophotographic photosensitive member of the coupling shaft of the twisted hole the electrophotographic photosensitive drum of said coupling shaft An axially moving means of the coupling shaft provided so as to take a position engaging with a twisted polygonal column protrusion provided at one end in the longitudinal direction of the drum;
f. A flange portion having a radial bearing outer periphery of the other end with a twisted hole of polygonal cross section of said coupling shaft is fitted in a freely movable in the axial direction moving rotation, the electrophotographic photosensitive member of the rotating body in the axial direction and a thrust bearing portion for axially supported so as not to move to the drum side integrally coupled bearings having an opening through which the axial movement means of the coupling shaft between said flange portion and the thrust bearing portion ,
g. Conveying means for conveying the recording medium;
An electrophotographic image forming apparatus comprising: In an electrophotographic image forming apparatus for detaching a process cartridge and forming an image on a recording medium,
a. An electrophotographic photosensitive drum;
Process means acting on the electrophotographic photosensitive drum;
Twist polygonal column protrusions provided at one end in the longitudinal direction of the electrophotographic photosensitive drum;
A cartridge mounting portion for detachably mounting a process cartridge having
b. A rotating body that is connected to the driving source and has a twisted hole with a polygonal cross section at the center, and is supported so as to be rotatable and not move in the axial direction;
c. A twisted polygonal column that fits into a twisted hole of the rotating body is provided at one end, and the other end engages and disengages from the protrusion of the electrophotographic photosensitive drum. A twist angle and a twist direction are twisted at the one end. A coupling shaft that is the same as the polygonal column and has a polygonal column twisted hole, a flange between the one end and the other end, and is rotatably supported in the axial direction.
d. A spring member for biasing the coupling shaft in the direction of said electrophotographic photosensitive drum,
e. An opening / closing member provided in the cartridge mounting portion;
f. A flange portion having a radial bearing outer periphery of the other end of holes torsion of polygonal section of said coupling shaft is fitted in a freely movable in the axial direction movement rotating said electrophotographic photosensitive drum in the axial direction of the rotary body and a thrust bearing portion for axially supported so as not to move to the side together, the cam lever having a spacer advancing and retracting between the flange of said coupling shaft and a thrust bearing portion between the thrust bearing portion and the flange portion A coupling bearing with an opening therethrough;
g. A flange of the coupling bearing has a cam inserted between the between the flanges of the coupling shaft, and coupled cam member to work with opening and closing operation of the opening and closing member to the closing member,
h. Conveying means for conveying the recording medium;
An electrophotographic image forming apparatus comprising:   The electrophotographic image forming apparatus according to claim 1, wherein the rotating body is a helical gear. The coupling shaft is fitted to the large diameter side and the small diameter side of a stepped crimping shaft having two large and small diameters coaxially fixed to a side plate that supports a member that transmits power to the rotating body. It has a stepped bore in which a compression spring for biasing the coupling shaft to the electrophotographic photosensitive drum side is inserted into the small diameter side of the stepped caulking shaft, one end of said compression spring parts in contact with the stepped poker is a boundary surface of the small diameter side to the large diameter side of the stepped caulking shaft, and the other end of the compression spring, is formed in the interior of the coupling shaft with the stepped 5. The electrophotographic image forming apparatus according to claim 1, wherein the electrophotographic image forming apparatus is contracted by coming into contact with a flange portion in a thrust direction fitted to the small diameter side of the caulking shaft. The section of the twisted hole of the coupling shaft is substantially triangular, and the shape of the protrusion is a twisted substantially triangular prism, wherein the corner of the substantially triangular prism is chamfered. The electrophotographic image forming apparatus according to any one of 4. Wherein the cartridge mounting portion is opened when detaching the process cartridge, wherein a closing member to said process cartridge to the cartridge mounting portion so as to close and mounted on the cartridge mounting portion, of the closing member and the coupling shaft The electrophotographic image forming apparatus according to claim 1, further comprising an interlocking member that interlocks with the axial movement unit. A body frame at intervals, has a side plate for supporting a member for transmitting power to the rotary body, rotatably to the body frame together with the coupling shaft is engaged with the caulking shaft fixed to the side plates 4. The electrophotographic image forming apparatus according to claim 1, wherein the electrophotographic image forming apparatus is positioned in a plane perpendicular to the axis of the coupling shaft by being supported by the support.

Images