JP4164529B2 - Electrophotographic photosensitive drum - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive drum used for a process cartridge.

  The process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive member 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 member 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 member are integrated into a cartridge so that it can be attached to and detached from the apparatus main body. Here, since the process cartridge can be attached to and detached from the apparatus main body by the user, maintenance of the apparatus main body can be easily performed.

  The electrophotographic image forming apparatus 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 apparatus, a word processor, and the like.

  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 member 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 photoreceptor is transferred to a recording medium by a transfer means to form an image.

  Here, various methods have been considered for rotationally driving the electrophotographic photosensitive drum.

  As one of the methods, as described in JP-A-62-65049, a pin fixed to a side surface of a gear provided on the main body is provided on a side surface of the gear provided to the photosensitive drum. In this method, the photosensitive drum is rotated by being fitted into the recess.

  Another method is as described in JP-A-63-4252, in which a helical gear provided on the main body and a helical gear provided on the photosensitive drum are fitted to each other for photosensitivity. This is a method of rotating a body drum.

  All the techniques described in the above publications are 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.

  An object of the present invention is to provide an electrophotographic photosensitive drum capable of improving the rotational accuracy of the electrophotographic photosensitive drum.

  Another object of the present invention is to provide an electrophotographic photosensitive drum capable of reliably transmitting a driving force from the apparatus main body to the electrophotographic photosensitive drum.

  Another object of the present invention is to provide an electrophotographic photosensitive member capable of improving the positioning accuracy of the electrophotographic photosensitive drum with respect to the apparatus main body in the longitudinal direction by pulling the cartridge protrusion by the concave portion of the main body when transmitting the driving force. To provide a drum.

  Another object of the present invention is to provide a main body convex portion inside the main body concave portion and also provide a cartridge concave portion in the cartridge projection, so that the main body convex portion enters the cartridge concave portion, so that the process cartridge remains mounted. An object of the present invention is to provide an electrophotographic photosensitive drum in which the cartridge protrusion and the main body recess are not damaged even if the image forming apparatus is transported or carried in this state.

A typical configuration according to the present invention for achieving the above object is as follows:
A motor, an apparatus main body gear that rotates in response to transmission of a driving force from the motor, a twisted main body recess having a polygonal cross section provided substantially coaxially with the apparatus main body gear; and the main body recess An electrophotographic image forming apparatus that forms an image on a recording medium, and is detachably mounted on the apparatus main body. In an electrophotographic photosensitive drum used for a process cartridge to be processed,
A cylinder having a photosensitive layer on its peripheral surface;
A twisted cartridge protrusion provided at one end in the longitudinal direction of the cylinder, the twisted cartridge protrusion engaging with the twisted main body recess when the process cartridge is mounted on the apparatus main body;
A cartridge recess provided in the cartridge protrusion substantially on the same axis as the cartridge protrusion, and the cartridge recess into which the main body protrusion enters when the process cartridge is attached to the apparatus main body;
Having
When the process cartridge is mounted on the apparatus main body, when the main body gear rotates with the main body convex part entering the cartridge concave part and with the cartridge protrusion fitted into the main body concave part, The rotational force of the main body gear is transmitted to the electrophotographic photosensitive drum via the main body recess and the cartridge protrusion, and the electrophotographic photosensitive drum rotates.

  As described above, according to the present invention, the rotational accuracy of the drive transmission can be improved, so that the rotational accuracy of the electrophotographic photosensitive drum can be improved.

  Further, according to the present invention, the driving force can be reliably transmitted from the apparatus main body to the electrophotographic photosensitive drum.

  According to the present invention, when the driving force is transmitted (when an image is formed), the concave portion of the main body attracts the cartridge protrusion, so that the positioning accuracy of the electrophotographic photosensitive drum relative to the main body of the apparatus can be improved. It was.

  According to the present invention, since the main body convex portion is provided inside the main body concave portion, it is possible to prevent foreign matter from entering the inside of the main body concave portion.

  Further, according to the present invention, the main body convex portion is provided inside the main body concave portion, and the cartridge concave portion is provided in the cartridge protrusion. Therefore, when the main body convex portion enters the cartridge concave portion, the process cartridge remains mounted. Even if the image forming apparatus is transported or carried in a state, the concave portion and the convex portion are not likely to be damaged.

  Next, an embodiment according to the present invention will be described with reference to the drawings.

[First Embodiment]
First, a process cartridge according to the first embodiment and an electrophotographic image forming apparatus to which the process cartridge can be detachably mounted will be specifically described with reference to FIGS. 1 to 10. Here, as an order of explanation, first, the overall configuration of the process cartridge and the electrophotographic image forming apparatus to which the process cartridge is mounted will be described with reference to FIGS. 1 to 6, and next, FIG. 3, FIG. 6, FIG. Referring to FIG. 10, a configuration of a coupling that is a driving force transmission mechanism between the process cartridge and the image forming apparatus main body will be described.

{overall structure}
1 is a schematic view of an electrophotographic image forming apparatus A in which a process cartridge is detachably mounted. FIG. 2 is a side sectional view of the process cartridge B. FIGS. 3 and 4 are external perspective views of the process cartridge. FIG. 6 is an explanatory diagram of a mounting configuration for mounting the process cartridge to the apparatus main body.

  As shown in FIG. 1, the electrophotographic image forming apparatus (in the embodiment, laser beam printer) A irradiates a drum-shaped electrophotographic photosensitive member 7 with laser light based on image information from an optical system 1 to A latent image is formed on the photosensitive member, and the latent image is developed with toner to form a toner image. In synchronism with the formation of the toner image, the recording medium 2 (recording paper or the like) is conveyed from a feeding cassette 3a to a pickup roller 3b, a feeding roller pair 3c, a conveying roller pair 3d, a registration roller pair 3e, and the like. Transport by. Then, 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 driving roller 5a and a fixing roller 5c having a built-in heater 5b. The fixing unit 5 fixes the transferred toner image to the recording medium 2 by applying heat and pressure to the passing recording medium 2.

  The recording medium 2 is conveyed by the discharge roller pairs 3g and 3h, and discharged to the discharge unit 6 through the reverse conveyance path. The image forming apparatus A can also be manually fed by a manual feed tray 3i and a roller 3j.

  On the other hand, the process cartridge B includes an electrophotographic photosensitive member and at least one process means. Here, as the process means, for example, a charging means for charging the electrophotographic photosensitive member, a developing means for developing the latent image formed on the electrophotographic photosensitive member, and a cleaning means for cleaning the toner remaining on the surface of the electrophotographic photosensitive member. Etc.

  As shown in FIGS. 1 and 2, the process cartridge B of this embodiment includes an electrophotographic photosensitive drum 7, a charging roller 8, an exposure opening 9, and a developing unit 10. The process cartridge B rotates the electrophotographic photosensitive drum 7 from the apparatus main body 13 by a coupling mechanism described later. Then, the surface is uniformly charged by applying a voltage to the charging roller 8 as a charging means, and the information light from the optical system 1 is exposed to the photosensitive drum 7 through the exposure opening 9 to form a latent image, This latent image is developed by the developing means 10.

  The developing means 10 feeds the toner in the toner storage portion 10a by the rotation of the feeding member 10b, rotates the developing roller 10d incorporating the fixed magnet 10c, and develops the toner layer to which the triboelectric charge is applied by the developing blade 10e. A toner image is formed on the surface of the roller 10d, and the toner is transferred to the photosensitive drum 7 in accordance with the latent image to form a visible image. Then, a voltage having a polarity opposite to that of the toner image is applied to the transfer roller 4 provided in the apparatus main body 13 to transfer the toner image to the recording medium 2. 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.

  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.

  The process cartridge B is welded (ultrasonic welding in this embodiment) to a toner frame 12a having a toner storage portion 10a for storing toner and a developing frame 12b for supporting a developing member such as the developing roller 10d. Construct a development unit. The developing unit is slidably coupled with a cleaning frame 12c that supports the photosensitive drum 7, the charging roller 8, the cleaning unit 11, and the like. The process cartridge B is detachably mounted by a user on a 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 a bearing 12c2 described later. Further, a guide 24c is provided on the bearing 24 (of the convex portion 24) attached to the cleaning frame 12c. In addition, this bearing 24, the convex part 24a, and the guide part 24c are integrally molded. The mounting guides 12c4 and 24c are guided by the guides 15a and 15c when the process cartridge B is mounted.

  As the cartridge mounting means, as shown in FIG. 5, cartridge mounting guide members 15 are mounted facing the left and right side surfaces of the cartridge mounting space provided in the apparatus main body 13 (FIG. 5 shows one side surface, FIG. The left and right guide members 15 are provided with guide portions 15a and 15c that are used as guides when the process cartridge B is inserted. The guide portions 15a and 15c are inserted by guiding bosses or the like, which will be described later, formed so as to protrude on both sides in the longitudinal direction of the cartridge frame. In order to attach the process cartridge B to the apparatus main body 13, the 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 A by closing the opening / closing cover 14. When the process cartridge B is taken out from the apparatus main body 13, the opening / closing cover 14 is opened.

  When the process cartridge B is mounted on the image forming apparatus A, as will be described later, the cartridge side coupling and the main body side coupling are coupled in conjunction with the closing operation of the opening / closing cover 14, and the photosensitive drum 7 and the like are connected to the apparatus. It can be rotated by driving from the main body.

{Coupling and drive configuration}
Next, the configuration of the coupling means that is a driving force transmission mechanism that transmits the driving force from the image forming apparatus main body 13 to the process cartridge B will be described.

  7 is a perspective view of a drum flange 16 as a driving force transmission component in which a convex shaft 17 is integrally formed, FIG. 8 is a partially cut perspective view of the photosensitive drum 7 to which the drum flange 16 is attached, and FIG. 8 is a cross-sectional view showing a state where the photosensitive drum 7 shown in FIG. 8 is attached to the process cartridge B, FIG. 10 is an enlarged perspective view of the vicinity of the convex shaft 17 of the process cartridge B shown in FIG. 9, and FIG. FIG. 6 is an explanatory diagram of a relationship between a convex shaft 17 (provided in the process cartridge B) and a concave shaft 18 (provided in the apparatus main body 13).

  Now, as shown in FIGS. 8 to 10 and FIG. 28, a cartridge side coupling means is provided at one longitudinal end of the photosensitive drum 7 attached to the process cartridge B. In this coupling means, a coupling convex shaft 17 (columnar shape) is provided on a drum flange 16 fixed to one end portion of the photosensitive drum 7, and a convex portion 17 a is formed on the tip surface of the convex shaft 17. It is. The end surface of the convex portion 17 a is parallel to the end surface of the convex shaft 17. The convex shaft 17 is fitted to the bearing 24 and functions as a drum rotation shaft. In this embodiment, the flange 16, the coupling convex shaft 17, and the convex portion 17a are provided integrally. The flange 16 is integrally provided with a helical gear 16a for transmitting a driving force to the developing roller 10d in the process cartridge. Therefore, as shown in FIG. 7, the drum flange 16 is an integrally molded product having a helical gear 16a, a convex shaft 17 and a convex portion 17a, and is a driving force transmission component having a function of transmitting a driving force.

  And the shape of the said convex part 17a is a twisted polygonal column, and is a shape twisted in the rotation direction of the axis | shaft in detail with the substantially regular triangular prism in detail. Further, the concave portion 18a fitted to the convex portion 17a is a hole twisted in the rotational direction of the polygonal shaft. The recess 18a has a substantially equilateral triangle cross section. And this recessed part 18a rotates integrally with the gear 34 provided in the apparatus main body 13. FIG. Therefore, in the configuration of the present embodiment, the process cartridge B is mounted on the apparatus main body 13, the convex portion 17a and the concave portion 18a provided in the apparatus main body 13 are fitted, and the rotational force of the concave portion 18a is the convex portion. When transmitted to 17a, the apexes of the convex portions 17a of the substantially regular triangular prism and the inner surface of the concave portion 18a come into contact with each other equally, so that the axes coincide with each other (FIGS. 18A and 18B). Further, due to the twisted shape, a force acts in a direction in which the concave portion 18 pulls the convex portion 17, and the convex portion end surface 17 a 1 comes into contact with the concave portion 18 a 1. Therefore, the position of the photosensitive drum 7 integrated with the convex portion 17a is determined stably in the axial direction and the radial direction in the image forming apparatus main body 13.

  Next, with respect to the shapes of the hole 17a2 provided at the tip of the convex portion 17a, the protrusion 18a4 provided inside the concave portion 18a, and the concave portion 18a, FIG. 7, FIG. 8, FIG. 9, FIG. , FIG. 22, FIG. 28, FIG. 29, FIG. 30, FIG. 31, FIG. 32, and FIG.

  18 is a sectional view of the coupling convex portion and the concave portion, FIG. 22 is a perspective view of the coupling convex portion and the concave portion, FIG. 28 is a perspective view of the coupling concave shaft, and FIG. 29 is an axis of the coupling convex portion and the concave portion. FIG. 30 is an axial sectional view of the coupling convex part and the concave part (showing a state before the convex part and the concave part are engaged), and FIG. 31 is a coupling convex part. And FIG. 32 is a sectional view around the coupling convex portion and the concave portion (showing a standby state), and FIG. 33 shows another embodiment. It is sectional drawing (at the time of driving force transmission) around a coupling convex part and a recessed part. 31 to 32 show a state in which the process cartridge B is mounted on the apparatus main body 13.

  As shown in the respective drawings described above, in the present embodiment, a hole 17a2 is provided at the tip of the convex portion 17a. The inner surface of the hole 17a2 is inclined inward as it goes from the tip side to the back side. It is a so-called “mortar” shape. The hole 17a2 has a circular cross section and is provided substantially coaxially with the convex portion 17a. The hole 17a2 reaches the bottom surface of the convex portion 17a (the front end surface of the coupling convex portion 17).

  A hole is also provided on the bottom surface of the hole 17 a 2, and the hole provided on the bottom surface penetrates the drum flange 16.

  On the other hand, a protrusion 18a4 is provided inside the recess 18a. The protrusion 18a4 has a so-called “mountain shape” that is inclined outward as it goes from the tip side to the back side. The protrusion 18a4 has a circular cross section and is provided substantially coaxially with the coupling concave shaft 18. Further, the protrusion is provided on the bottom surface of the recess 18 a and protrudes slightly inward from the tip surface of the recess shaft 18.

  When the process cartridge B is mounted on the apparatus main body 13 and the cover 14 is closed, the protrusion 18a4 enters the hole 17a2. At this time, there is play between the outer peripheral surface of the protrusion 18a4 and the inner peripheral surface of the hole 17a2 (see FIGS. 18A and 18B, FIG. 29, and FIGS. 31 to 33). As shown in each figure, there is play between the entire outer peripheral surface of the projection 18a4 and the entire inner peripheral surface of the hole 17a2 during drive transmission (FIG. 18B, FIG. 29, FIG. 31, and FIG. (See FIG. 33). Therefore, the protrusion 18a4 and the hole 17a2 do not affect the drive transmission. On the other hand, at the time of standby (at the time of non-driving force transmission), a part of the outer peripheral surface of the protrusion 18a4 and a part of the inner peripheral surface of the hole 17a2 are in contact (see FIGS. 18 (a) and 32).

  Further, as shown in FIGS. 29, 30 and 31, the relationship between the hole 17a2 and the protrusion 18a4 is such that the radial gap in the state where the convex shaft 17 and the concave shaft 18 are coupled is the convex portion 24a (described later). And a gap between the main body guide concave portion 15d (described later) and a radial gap between the coupling convex portion 17a and the concave portion 18a (about 0.3 mm to about 1.0).

  That is, the radial gap between the coupling convex part 17a and the concave part 18a is S, the gap between the convex part 24a and the main body guide concave part 15d is T, the hole 17a2 on the end face of the convex part 17a and the protrusion 18a4 inside the concave part 18a. When the radial clearance in the state where the convex shaft 17 and the concave shaft 18 are combined is U, the relationship of S ≧ T ≧ U is established.

  Further, as shown in FIGS. 29 and 30, when the radial gap between the entrance of the hole 17a2 and the tip of the protrusion 18a4 in the present embodiment is V, V ≧ S. Therefore, when the coupling convex portion 17a and the concave portion 18a are coupled, the hole 17a2 on the end surface of the convex portion 17a and the protrusion 18a4 inside the concave portion 18a do not interfere with each other.

  Further, the shape of the recess 18a will be described with reference to FIGS. 18 (a) and (b), FIG. 28, FIG. 31, FIG. 32, and FIG.

  The concave portion 18a fitted to the convex portion 17a is a hole twisted in the rotational direction of a polygonal shaft as a whole. That is, it functions as a twisted hole from the point of drive transmission.

  Accordingly, the convex portion 17a has a hole shape in which the cross section of the portion in contact with the convex portion 17a is twisted in the rotational direction of the polygonal shaft. However, the portion that does not come into contact with the convex portion 17 a has a shape that extends outward and extends along the outer periphery of the concave shaft 18. As a result, the thickness of the portion of the concave shaft 18 where the concave 18 a is provided is made as close as possible to the entire peripheral surface of the concave shaft 18. Specifically, the concave portion 18a has a substantially equilateral triangular cross section at the portion in contact with the convex portion 17a, and has a circular arc shape 18a3 along the outer periphery (circular shape) of the concave shaft 18 except for this portion.

  Next, the effect based on each structure mentioned above is demonstrated.

  First, since the convex portion 17a is an integrally molded product made of resin, by providing a hole 17a2 on the end surface of the convex portion 17a, variation in the resin temperature and pressure fluctuation in the mold are suppressed, and shrinkage after molding is performed. As a result, the shape accuracy of the convex portion 17a can be stabilized.

  Furthermore, since the concave portion 18a is also an integrally molded product made of resin, by forming an arc shape along the outer periphery of the concave shaft 18 other than the contact portion of the concave portion 18a with the convex portion 17a, The resin temperature variation and pressure fluctuation can be suppressed, shrinkage after molding can be reduced, and the shape accuracy of the recess 18a can be stabilized. From this, it is possible to minimize the rattling of the contact point and the rotation unevenness of the coupling drive due to the load fluctuation at the time of rotation of the process cartridge B, and to further improve the rotation accuracy of the photosensitive drum 7. Was made.

  Next, the effect brought about by combining the hole 17a2 and the protrusion 18a4 will be described.

  First, as described above, the relationship between the entrance of the hole 17a2 and the tip of the projection 18a4 is such that the radial gap is greater than or equal to the gap between the convex portion 24a and the main body guide portion concave portion 15d, so that the engagement between the convex portion 17a and the concave portion 18a is obstructed. Never become. In addition, the relationship between the hole 17a2 and the protrusion 18a4 is such that the radial gap when the convex shaft 17 and the concave shaft 18 are coupled is less than or equal to the radial gap between the coupling convex portion 17a and the concave portion 18a. Therefore, even when the process cartridge B is vibrated or transported with the process cartridge B mounted on the apparatus main body 13, the contact portion between the coupling convex portion 17a and the concave portion 18a is prevented from being damaged. I can do it. That is, as described above, a part of the outer peripheral surface of the protrusion 18a4 and a part of the inner peripheral surface of the hole 17a2 are in contact with each other during transport or image formation standby (non-driving force transmission) (FIG. 18A). , And FIG. 32). Therefore, even if the apparatus (printer or the like) is moved with the process cartridge mounted, the radial movement of the convex portions 17a and the concave portions 18a is restricted by the holes 17a2 and the projections 18a4. It can prevent beforehand that the convex part 17a and the recessed part 18a are damaged.

  Further, by providing the protrusion 18a4 in the recess 18a, when assembling at the factory, when the process cartridge is mounted on the apparatus main body, or when the process cartridge is removed from the apparatus main body for maintenance of the apparatus main body. For example, foreign matter can be prevented from entering the recess 18a. Therefore, it is possible to prevent the recess 18a from being damaged.

  In this embodiment, when viewed from the photosensitive drum 7 side, the twist direction of the convex portion 17a is opposite to the rotation direction of the photosensitive drum 7 from the root of the convex portion 17a toward the tip, The twist direction of the concave portion 18a is opposite to the inside from the inlet of the concave portion 18a, and the twist direction of the helical gear 16a of the drum flange 16 described later is opposite to the twist direction of the convex portion 17a.

  As shown in FIG. 18, the convex portion 17a and the concave portion 18a have a diameter of a circumscribed circle R0 of a triangular prism as the convex portion 17a = d0 and a diameter of an inscribed circle R1 in a space having a triangular section as the concave portion 18a. When d = d1 and the diameter of the circumscribed circle R2 = d2, the relationship is d1 <d0 <d2.

  Specifically, a preferred example of the numerical range is preferably d0 = about 3 mm to 70 mm, d1 = about 3 mm to 70 mm, and d2 = about 3 mm to 70 mm. Then, a size satisfying the above-described relationship may be appropriately selected from this numerical range. In this embodiment, d0 = about 16 mm, d1 = about 9.5 mm, and d2 = about 17.5 mm. Further, the amount of twist of the convex portion 17a is twisted at a rate of 1 ° to 15 ° in the rotation direction with respect to the axial length of about 1 mm of the convex portion 17a. Specifically, in this embodiment, the shaft is twisted at a rate of about 7.5 ° in the rotation direction with respect to the length of the axis of about 1 mm.

  The twist amount of the concave portion 18a is substantially the same as the twist amount of the convex portion 17a.

Further, specific examples of the sizes of the holes 17a2 and the protrusions 18a4 are as follows.
Diameter of tip side of hole 17a2 is about 1.0 mm to 50.0 mm (in this embodiment, about 7.5 mm)
The diameter of the bottom surface side of the hole 17a2 is about 1.0 mm to 50.0 mm (about 5.5 mm in this embodiment).
The depth of the hole 17a2 is about 1.0 mm to 30.0 mm (about 4.5 mm in this embodiment).
The diameter of the hole 18a4 on the tip side is about 1.0 mm to 50.0 mm (about 4.5 mm in this embodiment).
The diameter of the base side of the hole 18a4 is about 1.0 mm to 50.0 mm (about 6.5 mm in this embodiment).
Length of hole 18a4 (projection amount)
About 1.0 mm to 30.0 mm (in this embodiment, about 4.0 mm)
However, the shape and size of the convex portion 17a and the concave portion 18a are not limited to the above-described embodiment, and may be appropriately selected. For example, as shown in FIG. 11, the hole 17a2 may be a hole having a triangular cross section, and the protrusion 18a4 may be a triangular prism slightly smaller than the hole.

  However, the present invention is not limited to the above numerical values and numerical ranges, and may be selected as appropriate.

  Here, there are three contact points for determining the theoretical three-dimensional cross-sectional position. When the convex portions 17a and the concave portions 18a are substantially equilateral triangular prisms as in this embodiment, the convex portions 17a are substantially omitted. The apex of the equilateral triangle abuts on the condition that the cross section of the concave portion 18a is equal to the inner surface of the space of the equilateral triangle. From this, it is possible to minimize the wobbling of the contact point and the rotation unevenness of the coupling drive due to the load fluctuation during the rotation of the process cartridge B, and the rotation accuracy of the photosensitive drum 7 can be improved. (See FIG. 18).

  Here, when the drum flange 16 is attached to one end portion of the photosensitive drum 7, the convex shaft 17 and the convex portion 17 a are positioned coaxially with the axis of the photosensitive drum 7. Is provided. Reference numeral 16b denotes a fitting portion which is a portion to be fitted to the inner surface of the drum cylinder 7a when the drum flange 16 is attached to the photosensitive drum 7. The drum flange 16 is attached to the photosensitive drum 7 by “caulking” or “adhesion”. The drum cylinder 7a is covered with a photosensitive drum 7b (see FIGS. 8 and 9).

  A drum flange 25 is fixed on the other end side of the photosensitive drum 7. The drum flange 25 is integrally molded with a drum shaft 25a and a spur gear 25b (see FIG. 9).

  When the process cartridge B is mounted on the apparatus main body 13, the drum shaft 25 a (bearing 12 c 2) is fitted and positioned in the U groove 15 b (see FIG. 5) of the apparatus main body 13 and integrated with the flange 25. The molded spur gear 25b meshes with a gear (not shown) that transmits a driving force to the transfer roller 4.

  The drum flanges 16 and 25 are made of resin materials such as polyacetal, polycarbonate, polyamide, and polybutylene terephthalate. However, other materials may be appropriately selected and used.

  Further, around the convex portion 17a of the coupling convex shaft 17 of the process cartridge B, a circular convex portion 24a concentric with the convex shaft 17 is provided on the cleaning frame 12c (see FIGS. 3 and 9). . The convex portion 24a protects the coupling convex portion 17a when the process cartridge B is attached and detached, and is protected from scratches and deformation due to external force. Therefore, it is possible to prevent rattling and vibration during coupling driving due to the damage of the convex portion 17a.

  Further, the convex portion 24 a can also serve as a guide member when the process cartridge B is attached to and detached from the image forming apparatus main body 13. That is, when the process cartridge B is mounted on the main body A, the convex portion 24a and the main body side guide portion 15c come into contact with each other, and the convex portion 24a functions as a guide member when mounting the process cartridge B at the mounting position. The process cartridge B can be easily attached to and detached from the main body 13. Further, when the process cartridge B is mounted at the mounting position, the convex portion 24a is supported by the concave portion 15d provided in the guide portion 15c. When the coupling convex shaft 17 and the concave shaft 18 are aligned when driven during image formation, the convex portion 24a slightly floats from the U groove 15d (about 0.3 mm to 1.0 mm). The gap between the convex portion 24a and the main body guide portion 15a (concave portion 15d) is smaller than the radial gap between the coupling convex portion 17a and the concave portion 18a. Thus, the coupling convex portion 17a and the concave portion 18a can be engaged with each other in a state where the process cartridge B is mounted on the main body 13. A recess 18a is provided to face the U groove 15d. In addition, the shape of the convex portion 24a is not limited to the circular shape shown in the present embodiment, and may be guided by the guide portion 15c and supported by the U-groove 15d. An arc shape may be used. In the present embodiment, an example is shown in which a bearing 24 for rotatably supporting the shaft portion 17 and a circular convex portion 24a are integrally molded and screwed (not shown) to the cleaning frame 12c (see FIG. 9) The bearing 24 and the convex part 24a may be separate bodies.

  In the present embodiment, the drum shaft 25a is fitted to the bearing portion 12c2 provided on the cleaning frame 12c (see FIGS. 4 and 9), and the inner surface of the bearing 24 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 convex shaft 17 is fitted. Therefore, the photosensitive drum 7 is centered on the shafts 17 and 25a. In this embodiment, the photosensitive drum 7 is attached to the cleaning frame 12c so as to be movable in the thrust direction. This is due to consideration of mounting tolerances. However, the present invention is not limited to this, and the photosensitive drum 7 may not be movable in the sliding direction.

  Further, there is a relationship as shown in FIG. 9 between the photosensitive drum 7, the flange 16, and the coupling convex shaft 17. That is, the outer diameter of the photosensitive drum 7 (the outer diameter of the cylinder 7a) = D1, the helical gear root diameter = G, the photosensitive drum bearing diameter (the outer diameter of the shaft portion 17, the inner diameter of the bearing 24) = F. When the circumscribed circle diameter of the coupling convex portion = C and the fitting portion diameter (drum inner diameter) = D2 with the drum flange 16 of the photosensitive drum 7, D1> F ≧ C and G> D2 are established.

  The sliding load torque at the bearing portion can be reduced by D1> F, and when the flange portion is formed by the relationship of F ≧ C, the mold is normally divided in the direction of arrow H in the figure, but the undercut portion Therefore, the mold configuration can be simplified.

  Furthermore, because of the relationship of G> D2, the gear part mold shape is provided on the left mold in FIG. 6, so the right mold having a coupling shape and a complicated mold configuration is simplified. There are effects such as improving durability.

  The dimensional relationship is that when the relationship between the convex shaft 17 and the concave shaft 18 is reversed, that is, the concave portion 18a is provided on the photosensitive drum side, the convex portion 17a is provided on the apparatus main body side, and the polygonal circumscribing of the concave portion 18a The same effect can be obtained by setting the same relationship when the circle diameter = C.

  Specifically, as a preferred example of the numerical range, D1 = about 10 mm to 60 mm, G = about 10 mm to 70 mm, F = about 5 mm to 70 mm, C = about 3 mm to 70 mm, and D2 = about 9 mm to 59 mm are preferable. . Then, a size satisfying the above-described relationship may be appropriately selected from this numerical range. In this embodiment, D1 = about 30 mm, G = about 31 mm, F = about 16 mm, C = about 14 mm, and D2 = about 28 mm. However, the present invention is not limited to the numerical values and numerical ranges described above, and may be selected as appropriate.

  On the other hand, the image forming apparatus main body 13 is provided with main body coupling means. In the main body coupling means, a coupling concave shaft 18 (cylindrical shape) is disposed at a position coinciding with the photosensitive drum rotation axis when the process cartridge B is inserted (see FIGS. 6 and 13). As shown in FIG. 12, the coupling concave shaft 18 is a driving shaft integrated with a large-diameter gear 34 that transmits the driving force of the motor 30 to the photosensitive drum 7. (The concave shaft 18 is the center of rotation of the gear 34 and is provided so as to protrude from the side end of the gear 34 (see FIGS. 13 and 14). The coupling concave shaft 18 is formed by integral molding.

  The gear 34 on the main body side is constituted by a helical gear, which is concave when a driving force is transmitted from the helical gear 20 fixed to the shaft 30a of the motor 30. It has teeth with an inclination angle that generates thrust to move the shaft 18 in the direction of the convex shaft 17. Thus, when the motor 30 is driven during image formation, the concave shaft 18 is moved in the direction of the convex shaft 17 by the thrust, and the concave portion 18a and the convex portion 17a are engaged. The recess 18 a is provided at the tip of the concave shaft 18 and at the center of rotation of the concave shaft 18.

  In this embodiment, the driving force is directly transmitted from the gear 20 fixed to the motor shaft 30a to the gear 34, but the gear train is used for deceleration and driving transmission, or a belt and a pulley, a friction roller pair, A timing belt and a pulley may be used.

  Next, a configuration for fitting the concave portion 18a and the convex portion 17a in conjunction with the closing operation of the opening / closing cover 14 will be described with reference to FIGS.

  FIG. 15 is a view as seen from the axial direction of the photosensitive drum 7, and an outer cam 35 and an inner cam 36 (see FIG. 17) are arranged between the gear 34 and the photosensitive drum 7 (not shown), and the image forming apparatus. The cover 14 and the outer cam 35 are connected by a rod 37 to constitute a moving means. Reference numeral 40 denotes a side plate provided in the apparatus main body 13. In FIGS. 16 and 17, reference numeral 34 a denotes a shaft support portion for supporting the gear 34 on the side plate 39.

  FIG. 16 is a right side view of FIG. 15. When the cover 14 is closed, the rod 37, the outer cam 35, etc. are in the positions shown in the figure, and the coupling convex portion 17a and the concave portion 18a are engaged with each other. The driving force can be transmitted to the photosensitive drum 7. When the cover 14 is opened, as shown in FIG. 17, the outer cam 35 rotates by being pulled through the rod 37, and the outer cam 35 and the inner cam 36 come into contact with each other so that the gear 34 is moved to the photosensitive drum 7. Move further away. At that time, the gear 34 and the coupling concave shaft 18 are pushed by the outer cam 35 and moved in the same manner while pushing the spring 38 attached between the fixed plate 39 and the concave portion 18a is separated from the convex portion 17a. The coupling is released, and the cartridge B is in a removable state.

  On the other hand, when the cover 14 is closed, the cam 35 rotates in the reverse direction and is pushed by the spring 38, so that the gear 34 is set again to the position shown in FIG. By adopting such a configuration, it becomes possible to put the cartridge B into a detachable and driveable state according to the opening and closing of the cover 14.

  Thus, in the present embodiment, when the process cartridge B is attached to or detached from the apparatus main body 13, the cover 14 is opened. Then, in conjunction with the opening and closing of the cover 14, the recess 18a moves in the horizontal direction (the direction of the arrow j). Therefore, when the process cartridge B is attached to or detached from the apparatus main body 13, the coupling (17a, 18a) between the process cartridge B and the apparatus main body 13 is not connected. They are not connected. Therefore, the process cartridge B can be smoothly attached to and detached from the apparatus main body 13. In the present embodiment, the recess 18 a is pressed toward the process cartridge B by the spring 38. Therefore, when the convex portion 17a and the concave portion 18a mesh with each other, even if the convex portion 17a and the concave portion 18a collide with each other and do not mesh with each other, the concave portion 18a rotates and the both mesh instantaneously.

  Next, the shape of the convex part 17a and the concave part 18a which are the engaging parts of the coupling means will be described.

  The coupling concave shaft 18 provided in the apparatus main body 13 can be moved in the rotational axis direction as described above, but is positioned so as not to move in the rotational radius direction (radial direction). On the other hand, the process cartridge B is mounted on the apparatus main body 13 so as to be movable in the longitudinal direction of the photosensitive drum 7 and its rotational radius direction (radial direction).

  That is, when the process cartridge B is mounted on the apparatus main body 13, a portion (bearing 12c2) of the drum shaft 25a (see FIGS. 4 and 9) formed on the flange 25 attached to the other longitudinal end of the photosensitive drum 7 is the apparatus main body. 13, a spur gear 25b that enters the receiving portion (U groove) 15b (see FIG. 5), is fitted and positioned without any gap, and is molded integrally with the flange 25, and transmits a driving force to the transfer roller 4. (Not shown). On the other hand, on one end side (drive side) of the photosensitive drum 7 in the longitudinal direction, a convex portion 24 a provided on the cleaning frame 12 c is supported by a concave portion 15 d provided on the apparatus main body 13. When the cover 14 is closed, the concave portion 18a moves horizontally and enters the convex portion 17a (see FIG. 18A).

  Next, positioning and drive transmission are performed on the drive side (coupling side) as follows.

  First, when the main body drive motor 30 rotates, the coupling concave shaft 18 moves in the direction of the coupling convex shaft 17 (the direction of the arrow d in FIG. 13), and the phase of the convex portion 17a and the concave portion 18a is present (this embodiment). Then, since the convex portion 17a and the concave portion 18a are substantially equilateral triangles, they are engaged with each other at every 120 °), and the rotational force is transmitted from the apparatus main body 13 to the process cartridge B (FIG. 17). The state shown in FIG. 16 is changed to the state shown in FIG.

  In this coupling engagement, when the convex portion 17a enters the concave portion 18a, as shown in FIG. 18 (a), there is a difference in the size of the substantially equilateral triangle, that is, the concave portion 18a has a substantially equilateral triangular cross section. Since the hole is larger than the substantially equilateral triangle of the convex part 17a, it enters smoothly with a gap. Thus, the positioning accuracy of the coupling convex shaft 17 and the coupling concave shaft 18 may be in a rough state.

  In the present embodiment, the protruding amount of the circular convex portion 24a is larger than the protruding amount of the convex portion 17a (see FIG. 9). Therefore, when the convex portion 17a and the concave portion 18a are engaged, the inner surface of the circular convex portion 24a is fitted to the outer peripheral surface of the coupling concave shaft 18, and the guide when the both are engaged with each other is engaged. Fulfills the function.

  Then, when the coupling concave shaft 18 rotates with the convex portion 17a entering the concave portion 18a during image formation, as shown in FIG. 18B, the inner surface 18a1 of the concave portion 18a and the substantially equilateral triangular prism 3 of the convex portion 17a. The driving force is transmitted by contacting the point ridge line 17a1. At this time, the convex shaft 17 is instantaneously moved so that the inner surface 18a1 of the concave portion 18a and the ridge line 17a1 of the convex portion 17a are in equal contact (from the state shown in FIG. 18A to the state shown in FIG. 18B). Become). And since the convex part 17a and the recessed part 18a are substantially equilateral triangles, the axial center of the convex axis | shaft 17 and the concave axis | shaft 18 corresponds in the state in which contact | abutting force became uniform. That is, in a state where the convex portion 17a enters the concave portion 18a, the rotational center X1 of the convex portion 17a and the rotational center X2 of the concave portion 18a are displaced from each other (FIG. 18A). Then, when the concave portion 18a starts to rotate and comes into contact with the three ridge lines 17a1 of the convex portion 17a, the rotational centers X1 and X2 substantially coincide with each other.

  With the configuration described above, the coupling shafts 17 and 18 are automatically substantially aligned when the motor 30 is driven. Further, the driving force is transmitted to the photosensitive drum 7 to generate a rotational force in the process cartridge B, and the rotational force causes a contact portion 12c1 (see FIGS. 3 and 4) provided on the upper surface of the cleaning frame 12c of the process cartridge B. ) Abuts against a contact portion 13a (see FIG. 1) fixed to the image forming apparatus main body 13, and the position of the process cartridge B with respect to the image forming apparatus main body A is determined.

  Further, when not driven (non-image formation), a gap is provided in the rotational radius direction (radial direction) between the convex portion 17a and the concave portion 18a, so that the process cartridge for mounting the couplings and for the image forming apparatus main body is provided. It becomes easy to put on and take off. Further, since the abutting force at the coupling engaging portion described above is stabilized during driving, rattling and vibration at this portion can be suppressed.

In this embodiment, the shape of the coupling convex portion and the concave portion is a substantially regular triangle.
Needless to say, the same effect can be obtained with a substantially regular polygonal shape. In addition, positioning can be performed more accurately if it is a substantially regular polygonal shape, but may be a polygonal shape or the like as long as it is a shape that can be pulled and engaged without being limited thereto.

  Furthermore, when the coupling convex part is compared with the concave part, the convex part is easily damaged in shape and is inferior to the concave part in terms of strength. For this reason, in the present embodiment, a coupling convex portion is provided in the replaceable process cartridge B, and a coupling concave portion is provided in the image forming apparatus main body 13 requiring higher durability.

  Here, the embodiment described above is summarized by taking the process cartridge B as an example as follows. The process cartridge B of the present embodiment is integrated with the motor 30, the device main body gear 34 for receiving the driving force from the motor, and the device main body gear provided at the center of the device main body gear. The rotating body has a polygonal twisted hole 18a, and is detachable from the apparatus main body 13 of the electrophotographic image forming apparatus A that forms an image on the recording medium 2. The process cartridge of this embodiment includes an electrophotographic photosensitive drum 7, process means (charging roller 8, developing roller 10, cleaning blade 11a) that act on the electrophotographic photosensitive drum, and the electrophotographic photosensitive drum. A twisted polygonal column protrusion (convex portion 17a) fitted to the polygonal twisted hole provided at one end in the longitudinal direction, and when the process cartridge B is attached to the apparatus main body 13, When the main body gear 34 rotates with the projection 17a of the polygonal column engaged with the twisted hole 18a having a polygonal cross section, the main body gear 34 is pulled in the direction of the hole 18a. Is transmitted to the electrophotographic photosensitive drum 7.

  Moreover, the hole 17a2 is provided in the end surface of the protrusion 17a, and it fits with the protrusion 18a4 of the recessed part 18a with play.

  Further, the protrusion 17 a is provided to protrude from the tip end portion of the shaft portion 17 that protrudes from the rotation center of the drum 7 to the outside in the longitudinal direction of the drum. Here, the shaft portion is for rotatably supporting the drum 7 on the cartridge frame 12c.

  The shaft portion 17 is provided at the center portion of the helical gear 16a, and the electrophotographic photosensitive drum is disposed on the opposite side of the helical gear 16a from the shaft portion. An engaging portion 16 b for engaging with the inner surface of 7 is provided. Here, the protrusion 17a, the shaft portion 17, the helical gear 16a, and the engaging portion 16b are integrally molded products made of resin. The helical gear transmits a rotational force to the developing roller 10a as the process means.

  Further, a circular outer wall 24a provided so as to surround the projection 17a of the polygonal column or an arc-shaped outer wall provided along a part of the projection of the polygonal column is provided. Here, the outer wall 24a serves as a guide when the hole 18a and the protrusion 17a are moved relative to each other to be fitted.

  Further, when the outer diameter of the electrophotographic photosensitive drum 7 is D1, the outer diameter of the shaft portion 17 is F, and the diameter of a circumscribed circle of the projection 17a of the polygonal column is C, the relationship is D1> F ≧ C. .

  Further, the outer diameter of the shaft portion 17 is F, the diameter of the circumscribed circle of the projection 17a of the polygonal column is C, the tooth root diameter of the gear 16a provided on the electrophotographic photosensitive drum 7 is G, and the electrophotography When the inner diameter of the photosensitive drum 7 is D2, G> D2 and G> F ≧ C.

  Further, if the outer diameter D1 of the electrophotographic photosensitive drum 7 and the root diameter of the apparatus main body gear 34 are L, L is preferably about 1.0 to 5.0 times D1. This relationship may be appropriately selected in consideration of the space of the apparatus main body, desired image quality, and the like.

  Moreover, it is not limited to this numerical range. Incidentally, it is about 3 times in this embodiment.

  The module of the apparatus main body gear 34 is about 0.4 to 0.7. The root diameter L of the apparatus main body gear 34 is about 30 mm to 150 mm, and the number of teeth of the apparatus main body gear 34 is about 40 to 400 teeth. These numerical values may be appropriately selected in consideration of the space of the apparatus main body and the desired image quality. Moreover, it is not limited to this numerical range. Incidentally, in this embodiment, the module of the gear 34 is about 0.5, L is about 100 mm, and the gear 34 has 200 teeth.

  Here, the positioning of the process cartridge B with respect to the apparatus main body 13 during image formation (drive transmission) is summarized as follows.

  First, the process cartridge B is positioned by fitting the bearing 12c2 into the U groove 15b during non-image formation (non-driving). The convex portion 24a is simply supported by the receiving portion 15d, and at the same time, after the concave shaft 18 moves in the direction of the photosensitive drum 7, the projection 18a4 also receives the hole 17a2, and the process cartridge B in the apparatus main body A is received. The position of is roughly regulated. At the time of image formation (drive transmission), the process cartridge B is positioned in a state in which the convex portion 17a is attracted to the concave portion 18a provided in the apparatus main body 13 and the convex portion 17a and the concave portion 18a are engaged with each other. The That is, at the time of image formation, the process cartridge B is positioned by one end in the longitudinal direction of the photosensitive drum 7 by the U groove 15b and the other end by the recess 18a.

  In this embodiment, the photosensitive drum 7 is provided so as to be movable in the longitudinal direction (about 0.1 mm to 1.0 mm) in consideration of assembly tolerances. Therefore, when the convex portion 17a is attracted to the concave portion 18a, the end portion 16c (FIGS. 7, 8, and 9) of the drum flange 16 comes into contact with the end portion 24b of the bearing 24. In consideration of assembly tolerances, the process cartridge B mounted so as to be movable (about 0.1 to 3 mm) with respect to the main body side plates (mounting guide portions 15a and 15c) has a longitudinal direction of the photosensitive drum 7, and , Drawn in the radial direction (moves substantially obliquely upward). When the end portion 16c is in contact with the end portion 24b from the beginning, or when the photosensitive drum 7 has no play in the longitudinal direction, the process cartridge B is immediately inserted into the longitudinal direction of the photosensitive drum 7. Direction and radial direction (move substantially diagonally upward).

  Further, the process cartridge B receives a rotational force in the rotational direction of the photosensitive drum 7 during image formation, and the contact portion 12c1 contacts the fixed portion 13a by this rotational force.

  Accordingly, the process cartridge B is positioned in the apparatus main body 13 in the longitudinal direction and radial direction of the photosensitive drum 7 during image formation.

  When the process cartridge B is pressed by an elastic member (for example, the embodiment shown in FIG. 21), the process cartridge B does not move in the longitudinal direction of the photosensitive drum 7 depending on the magnitude of the elastic force of the elastic member. Is also possible. However, even in this case, when drive is transmitted, the process cartridge B moves in the radial direction of the drum 7 (move substantially upward), and positioning with respect to the apparatus main body 13 is performed. In this case, the process cartridge B is similarly positioned with respect to the apparatus main body 13 even when the photosensitive drum 7 has no play in the longitudinal direction.

[Second Embodiment]
Next, another embodiment of the shape of the convex portion 17a of the coupling convex shaft 17 will be described with reference to FIG. Since the basic configuration of the process cartridge and the image forming apparatus is the same as that of the first embodiment described above, duplicate description is omitted, and members having the same functions as those of the first embodiment are denoted by the same reference numerals. .

  The coupling protrusion 17a shown in FIG. 19 is different from the above-described embodiment in that the shape of each item point 17a2 of the substantially regular polygonal column shape (substantially regular triangle in FIG. 19) of the protrusion is chamfered. is there. This chamfering may be an R shape in FIG. 19A or a shape in which the vertices of a substantially regular polygon are linearly dropped as shown in FIG. 19B.

  With the above-described configuration, it is possible to prevent the apex of the convex portion 17a from being crushed when the process cartridge B is operated or when the coupling is engaged. In driving, it is possible to suppress deflection and deformation due to insufficient strength of each item. Therefore, it is possible to prevent the alignment accuracy between the convex shaft 17 and the concave shaft 18 from being lowered, and to suppress rattling and vibration at the coupling portion.

  In FIG. 19 (a), the portion in contact with the inner surface of the recess is the shape of FIG. 19 (a), as can be easily understood if this shape is introduced as the shape of the protrusion 17a of FIG. 18 (b). It is not the outermost part of, but a part slightly deviated therefrom (at each vertex). From the viewpoint of alignment accuracy, it is preferable that these three contact points form a substantially equilateral triangle.

  Similarly, in FIG. 19B, it is preferable that the three contact points form a substantially equilateral triangle.

  Similarly, in the example of the polygonal column convex portion (polygonal cross-section concave portion), the convex portion and the concave portion substantially contact at three points, and these three points form a substantially equilateral triangle from the viewpoint of alignment accuracy. preferable.

  When FIG. 19A is used, each contact is not a single point but has a slight width. In that case, the central portion of the width (or the end in the same direction of the width) may be regarded as the contact.

[Third Embodiment]
Next, another embodiment of the shape of the convex portion of another coupling convex shaft 17 will be described with reference to FIG. Since the basic configurations of the process cartridge and the image forming apparatus are the same as those in the above-described embodiment, redundant description is omitted, and members having the same functions as those in the above-described embodiment are denoted by the same reference numerals.

  In the first embodiment described above, the flange 16 and the coupling convex shaft 17 of the photosensitive drum 7 are integrated. However, as shown in FIG.

  If the coupling convex shaft 17 is separated from the flange 16 as in this embodiment, the coupling drum 17 is engaged with the flange 16 after the photosensitive drum 7 with the flange 16 is assembled into the frame 12c. Since it can be incorporated into the portion 16b by press fitting or the like, the photosensitive drum 7 does not have to be assembled to the frame 12c from an oblique direction.

[Fourth Embodiment]
Next, another embodiment of the positioning configuration of the process cartridge to the image forming apparatus main body using the coupling configuration of the present invention will be described with reference to FIG. Note that the basic configurations of the process cartridge and the image forming apparatus are the same as those in the above-described embodiment, and therefore redundant description is omitted, and members having the same functions as those in the above-described embodiment are denoted by the same reference numerals.

  As shown in FIG. 21, the image forming apparatus main body 13 is provided with an elastic member 13 b for urging the process cartridge B in the rotation direction of the photosensitive drum 7. The elastic member 13b contacts the contact portion 12c3 of the cleaning frame 12c of the process cartridge B with the process cartridge B mounted on the main body, and the rotational force in the same direction as the rotation direction of the photosensitive drum 7 is applied to the process cartridge B. (See FIGS. 3, 4, and 21). The process cartridge B to which the rotational force is applied tries to rotate in the rotation direction of the photosensitive drum 7 (clockwise direction in FIG. 21), but the contact portion 12c1 of the frame 12c and the contact portion 13a of the main body come into contact with each other. Held in a state. As a result, it is possible to prevent the process cartridge B urged in the rotation direction of the photosensitive drum 7 by the coupling driving force from vibrating in the rotation direction due to a load variation inside the process cartridge B. The contact portion 12c3 is provided at two locations on the upper surface of the cleaning frame 12c on one end side and the other end side in the longitudinal direction of the photosensitive drum 7 (see FIGS. 3 and 4).

[Fifth Embodiment]
Next, another embodiment of the coupling structure of the present invention will be described with reference to FIG.

  Note that the basic configurations of the process cartridge and the image forming apparatus are the same as those in the above-described embodiment, and therefore redundant description is omitted, and members having the same functions as those in the above-described embodiment are denoted by the same reference numerals.

  In the present embodiment, as shown in FIG. 22, the convex portion 17a of the coupling convex shaft 17 and the concave portion 18a of the concave shaft 18 have a substantially quadrangular cross section perpendicular to the shaft, and are further twisted in the rotational direction of the shaft. It has a shape. As in the first embodiment, a durable coupling recess 18 a is provided in the image forming apparatus main body 13. In this configuration, when driving is transmitted with the coupling engaged, the twisted shape causes a force in the direction in which the coupling concave shaft 18 pulls the convex shaft 17 in the axial direction, and the convex portion of the coupling convex shaft 17 The end surface 17a1 and the concave bottom surface 18a1 abut (or the convex shaft end surface 17b and the concave shaft end surface 18b abut).

  In the present embodiment, the hole 17a2 has a rectangular cross section, and the protrusion 18a4 has a rectangular parallelepiped shape slightly smaller than the hole 17a2. Also in this embodiment, a part of the recess 18a may be expanded outward.

  As a result, during driving, the position of the process cartridge B in the image forming apparatus main body A is always constant in the coupling axis direction, so that vibration of the process cartridge can be suppressed.

  In this embodiment, the shape of the cross section in the direction perpendicular to the axes of the convex portions 17a and the concave portions 18a of the coupling shaft is a substantially square shape. However, the cross sectional shape is not limited to this, and the coupling concave portion rotates. Other twisted polygonal column shapes that can be engaged with the protrusions at the time may be used.

  Further, when the process cartridge B is removed from the apparatus main body, if the motor 30 is driven in the direction opposite to that at the time of image formation, the coupling between the gear 34 and the gear 33, which are helical gears, is performed. Is automatically released. In this case, the coupling release mechanism as described in the first embodiment may not be provided.

[Sixth Embodiment]
Next, another embodiment will be described with reference to FIG. The embodiment shown in FIG. 23 is different from the first embodiment in that no gear is provided on the drum flange 16.

  23 (a) and 23 (b), the main body side coupling means is constituted by a coupling concave shaft 17 made of polyacetal (POM), and the cartridge side coupling means engaged therewith is POM. The coupling convex shaft 18 is made of. A cylindrical wall portion 24 concentric with the rotation center of the photosensitive drum 7 is provided integrally with the flange 16 around the coupling convex shaft 18. FIG. 23 (b) is a view taken along arrows D and E in FIG. 23 (a), respectively.

  Further, by providing the wall portion 24 having the same height as the convex portion 18a around the convex shaft 18, the convex portion 18a does not protrude from the cartridge frame, and the end portion of the convex portion 18a is prevented. Damage can be prevented.

  Further, as described above, the cylindrical wall portion 24 can be used as a guide when the process cartridge B is attached or detached along the guide portion 15c (see FIG. 6) of the image forming apparatus A.

[Seventh Embodiment]
Next, another embodiment will be described with reference to FIGS. In the embodiment described below, a concave shaft 117 is provided on the drum flange 116 provided on the photosensitive drum 7 and the large-diameter gear 121 provided on the apparatus main body 13 is protruded, contrary to the above-described embodiments. A shaft 118 is provided. This also improves the rotational accuracy of the photosensitive drum 7.

  As shown in FIG. 24, also in the present embodiment, the convex portion 118a of the substantially triangular prism of the coupling convex shaft 118 is twisted in the rotational direction, and the concave portion 117a of the coupling concave shaft 117 is also corresponding to this. The shape is twisted in the rotational direction. A seating surface 117 b is provided on the end surface of the coupling concave shaft 117.

  By making the engaging portion twisted in the rotational direction as described above, when the coupling convex shaft 118 rotates in the image forming direction (arrow c direction) in the engaged state, the coupling convex shaft 118 is concave. The shaft 117 is pulled until it contacts the seating surface 117b. As a result, the coupling between the two becomes more reliable.

  Further, when the process cartridge B is taken out from the apparatus main body 13, as shown in FIG. 25, when the motor 119 is driven in the opposite direction (arrow d direction) to the time of image formation, the pinion gear 120 made of helical gears and Due to the thrust with the transmission gear 121, the coupling can be automatically released.

  In this embodiment, if the allowable transmission torque of the concave shaft 117 is configured to be smaller than the allowable transmission torque of the convex shaft 118, damage to the convex shaft 118 can be prevented.

  For example, the coupling concave shaft provided in the cartridge is constituted by polyacetal (POM), and the coupling convex shaft provided in the main body is constituted by zinc die casting. If comprised in this way, when abnormal torque generate | occur | produces, since the allowable transmission torque of the coupling convex shaft of a main body side is large, it is prevented that the said convex shaft is damaged.

  The above-described embodiment is the same as the first embodiment described above except that the drum flange is provided with a concave shaft and the apparatus body is provided with a convex shaft. Therefore, in the embodiment in which the above-described embodiment is applied to an electrophotographic image forming apparatus, a process cartridge, a drive transmission component, and an electrophotographic photosensitive drum, the convex shaft provided on the drum flange in the first embodiment is a concave shaft. Instead, the concave shaft provided in the gear of the apparatus main body is replaced with a convex shaft, and the description of the first embodiment is cited.

  As a precaution, the process cartridge will be described as an example. The motor 30 (119) and the apparatus main body helical gear 34 (121) for receiving the driving force from the motor 30 (119) will be described. The apparatus body has a twisted substantially triangular prism protrusion 118a that rotates integrally with the helical gear provided at the central portion of the helical gear 34 (121). The process cartridge B is detachable from the apparatus main body 13 of the electrophotographic image forming apparatus A. That is, the process cartridge B includes cartridge frames 12a, 12b and 12c, the electrophotographic photosensitive drum 7 (107), the charging roller 8 for charging the electrophotographic photosensitive drum 7 (107), A cleaning blade 11a for removing toner remaining on the electrophotographic photosensitive drum 7 (107); a developing roller 10d for developing a latent image formed on the electrophotographic photosensitive drum 7 (107); The electrophotographic photosensitive drum 7 (107) has a twisted hole 117a that is provided at one end in the longitudinal direction and has a substantially triangular cross section that fits with the protrusion 118a. When the process cartridge B is attached to the apparatus main body 13, the helical gear 34 (121) rotates while the hole 117a is engaged with the protrusion 118a, so that the hole 117a is With the main body pulled in the direction of the protrusion 118a, the rotational force of the helical gear 34 (121) is transmitted to the electrophotographic photosensitive drum 7 (107). The hole 117a is recessed at the tip of a shaft portion 17 (117) provided at the center of the drum helical gear 16a (116a). The drum helical gear 16a (116a) is for transmitting a rotational force to the developing roller 10d. The shaft portion 17 (117) is for rotatably supporting the electrophotographic photosensitive drum 7 (107) on the cartridge frame 112c. The drum helical gear 16 (116a) and the shaft portion 17 (117) of the hole 117 are integrally formed of resin. Further, if the outer diameter of the electrophotographic photosensitive drum 7 (107) is D1, the outer diameter of the shaft portion is F, and the diameter of the circumscribed circle of the hole shape 117a is C, the relationship is D1> F> C. .

  In addition, the outer diameter of the shaft portion 17 (117) is F, the diameter of the circumscribed circle of the hole shape is C, the tooth root diameter of the gear provided on the electrophotographic photosensitive drum is G, and the electrophotographic photosensitive member. Assuming that the inner diameter of the drum is D2, G> D2 and G> F> C.

  Further, when the outer diameter of the electrophotographic photosensitive drum 7 (107) is D1 and the root diameter of the apparatus main body gear 34 (121) is L, L is approximately 1.0 to 5.0 times D1. It is as follows. The module of the apparatus main body gear 34 (121) is about 0.4 to 0.7. The root diameter L of the apparatus main body gear is about 30 mm to 150 mm, and the number of teeth of the apparatus main body gear is about 40 to 400 teeth.

  In this embodiment, as viewed from the photosensitive drum 7 (107) side, the twist direction of the convex portion 118a is from the root of the convex portion 118a to the tip with respect to the rotational direction of the photosensitive drum 7 (107). The twist direction of the hole 117a is the same direction from the inlet of the hole 117a toward the inside, and the twist direction of the drum flange 16a (116a) is opposite to the twist direction of the hole 117a.

[Eighth Embodiment]
In the first embodiment described above, when the cover 14 is opened, the rod 37 and the cam 35 are operated in conjunction with this to release the engagement between the coupling convex portion 17a and the concave portion 18a. The coupling release configuration may be configured as shown in FIGS.

  That is, as shown in FIG. 26A, the opening / closing cover 14 is attached with an arc-shaped release member 140 centered on the shaft 14a, and the distal end portion of the release member 140 is shown in FIG. Thus, the cam part 140a which becomes thick gradually is formed. Therefore, as shown in FIGS. 27A and 27B, when the cover 114 is opened to remove the process cartridge B, the cam portion 140a is located between the wall portion 141, the concave shaft 18, and the integral gear 34. Enter and push the side of the gear 34 in the direction of arrow b in FIG. As a result, the concave shaft 18 is retracted from the wall 141 and the engagement with the coupling convex shaft 17 provided on the photosensitive drum 7 is released, so that the process cartridge B can be removed smoothly.

  The member for attaching the release member 140 is not limited to the opening / closing cover 14 as long as it is a member that operates when the process cartridge B is attached / detached. Further, when the drive transmission gear 34 is constituted by a helical gear, the coupling can be released by the thrust of the helical gear even if the releasing member 140 is not necessarily provided.

[Other Embodiments]
In the first embodiment described above, the coupling provided on the photosensitive drum is configured by the convex shaft 17, and the coupling provided on the main body is configured by the concave shaft 18. However, the concave shaft and the convex shaft are photosensitive. Even if the body drum side and the apparatus main body side are interchanged, the same effect on the rotational accuracy of the photosensitive drum can be obtained (see FIGS. 23 and 24). At this time, the configuration is such that the allowable transmission torque of the concave shaft provided on the photosensitive drum is smaller than the allowable transmission torque of the convex shaft provided on the main body of the device, so that the convex shaft provided on the main body of the device is damaged. Can be prevented.

  For example, the concave shaft provided on the photosensitive drum is formed of polyacetal (POM), and the convex shaft provided on the apparatus main body is formed by zinc die casting. If comprised in this way, when abnormal torque generate | occur | produces, since the allowable transmission torque of the coupling convex shaft provided in the main body is large, it can prevent that a convex shaft is damaged.

  In the above-described embodiment, if the tip of the convex portion 17a and / or the inlet portion of the concave portion 18a are tapered, the convex portion 17a and the concave portion 18a are more smoothly coupled. .

  3, 6, 13, 14, 20, 23, and 24 to 27, the holes 17 a 2, the protrusions 18 a 4, and the arc shape 18 a 3 are not shown. This is to avoid complication of the drawing.

  Still another embodiment will be described with reference to FIGS. 34 and 35. FIG. In the present embodiment, a lid that can be opened and closed is provided in the hole 17a2. According to the present embodiment, it is possible to prevent foreign matter from entering the hole 17a2.

  Since the basic configuration of the process cartridge and the image forming apparatus is the same as that of the first embodiment described above, redundant description is omitted, and members having the same functions as those of the first embodiment are denoted by the same reference numerals. Is attached.

  In the present embodiment, a lid 19 for closing the hole 17a2 on the end surface of the convex portion 17a is provided. The lid 19 has a portion 19b that fits the lid portion 19a and the inside 16c of the drum gear 16a, and a portion 19c that fits the spring 20. Further, a spring receiving member 21 is attached to the drum gear 16 by adhesion or the like.

  When the process cartridge B is not attached to the apparatus main body 13, as shown in FIG. 34, the lid 19 is urged by the spring 20, and the fitting portion 19b comes into contact with the drum gear abutting portion 16d. In this state, the lid portion 19a closes the hole 17a2. When the process cartridge B is mounted on the apparatus main body 13, the lid portion 19a is pushed in the axial direction by the projection 18a4 of the main body gear shaft portion 18, the spring 20 is bent, and the projection 18a4 enters the hole 17a2.

  This embodiment also has the same effect as each of the above-described embodiments, and further, has an effect of preventing foreign matter and the like from entering the hole 17a2 or the photosensitive drum 7 because the hole 17a2 is blocked.

  The process cartridge B described above is for forming a single color image. However, the process cartridge is not limited to the case of forming a single color image. The present invention can also be suitably applied to a cartridge that forms a three-color image or full color).

  As the developing method, various developing methods such as a known two-component magnetic brush developing method, cascade developing method, touch-down developing method, and cloud developing method can be used.

  Examples of the electrophotographic photosensitive member include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and an organic photoconductor (OPC). As a method for mounting the photoconductor, a photoconductor is vapor-deposited or coated on a cylinder made of aluminum alloy or the like.

  In addition, the charging means is configured by using the so-called contact charging method in the first embodiment described above. However, as another configuration, a metal shield such as aluminum is provided around three sides of a tungsten wire that has been conventionally used. Of course, it is also possible to use a configuration in which positive or negative ions generated by applying a high voltage to the surface of the photosensitive drum are moved to the surface of the photosensitive drum and the surface of the drum is uniformly charged.

  In addition to the roller type, the charging unit may be a blade type (charging blade), a pad type, a block type, a rod type, a wire type, or the like.

  Further, as a method for cleaning the toner remaining on the photosensitive drum, the cleaning unit may be configured using a blade, a fur brush, a magnetic brush, or the like.

  The process cartridge described above includes, for example, an electrophotographic photosensitive member and at least one process means. Therefore, as an aspect of the process cartridge, in addition to the above-described embodiment, for example, an electrophotographic photosensitive drum and a charging unit are integrated into a cartridge so that it can be attached to and detached from the apparatus main body.

  An electrophotographic photosensitive drum and developing means are integrated into a cartridge that can be attached to and detached from the apparatus main body. An electrophotographic photosensitive drum and cleaning means are integrally formed into a cartridge that can be attached to and detached from the apparatus main body. Furthermore, there is an electrophotographic photosensitive drum and two or more of the above process means that are combined into a single cartridge that can be attached to and detached from the apparatus main body.

  In other words, the process cartridge described above is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum are integrally formed, and this 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 image forming apparatus main body. Further, it means that at least the developing means and the electrophotographic photosensitive drum are integrally formed into a cartridge so as to be detachable from the apparatus main body. The process cartridge can be attached to and detached from the apparatus main body by the user. Therefore, maintenance of the apparatus main body can be performed by the user himself.

  Further, in the above-described embodiment, the photosensitive drum and the developing roller are made into cartridges, and an apparatus for forming an image by attaching the process cartridge is exemplified. The present invention can be similarly applied to an image forming apparatus directly attached.

  Further, in the above-described embodiment, the laser beam printer is exemplified as the image forming apparatus. However, the present invention is not limited to this, and is used for other image forming apparatuses such as an electrophotographic copying machine, a facsimile machine, or a word processor. Of course it is also possible.

  As described above, by providing a hole in the end face of the coupling convex part, it is possible to suppress variations in resin temperature and pressure fluctuations within the mold, reduce shrinkage after molding, and stabilize the convex shape accuracy. I can do it. Furthermore, since the concave portion is also an integrally molded product, the resin temperature in the mold can be reduced by forming a part of the concave portion (other than the contact portion with the convex portion) along the outer periphery of the concave shaft. It is possible to suppress variations and pressure fluctuations, reduce shrinkage after molding, and stabilize the shape accuracy of the recesses. From this, it is possible to minimize the rattling of the contact point and the rotation unevenness of the coupling drive due to the load fluctuation at the time of rotation of the process cartridge B, and the rotation accuracy of the photosensitive drum 7 can be improved. I can do it.

  Also, a hole is provided on the end face of the convex portion, a protrusion is provided inside the concave portion, and the gap is fitted with a gap, the radial gap between the coupling convex portion and the concave portion is S, and the gap between the convex portion and the main body guide concave portion is T, The apparatus main body has a relationship of S ≧ T ≧ U, where U is a radial clearance in the state where the convex shaft and the concave shaft of the end face of the convex portion and the protrusion inside the concave portion are coupled to each other. It is possible to prevent the contact portion between the coupling convex portion and the concave portion from being damaged when transported in a state where the process cartridge is mounted.

  V ≧ S, where V is the radial gap between the hole entrance and the tip of the protrusion. For this reason, when the coupling convex portion and the concave portion are coupled, the hole on the end face of the convex portion and the protrusion inside the concave portion do not interfere with each other.

  That is, as described above, the hole 17a2 on the end face of the convex portion 17a and the protrusion 18a4 inside the concave portion 18a have a radial gap between the coupling convex portion 17a and the concave portion. Since it is more than the radial gap with respect to 18a, the engagement of the convex portion 17a and the concave portion 18a is not hindered. In addition, the relationship between the hole 17a2 and the protrusion 18a4 is such that the radial gap when the convex shaft 17 and the concave shaft 18 are coupled is less than or equal to the radial gap between the coupling convex portion 17a and the concave portion 18a. When the process cartridge B vibrates when not being driven, for example, when the process cartridge B is transported with the apparatus main body A mounted or carried by the user, the contact between the coupling convex portion 17a and the concave portion 18a It is possible to prevent the portion from being damaged (see FIG. 32). Specifically, even if vibration is generated, damage to the coupling convex portion 17a and the concave portion 18a can be prevented by the main body guide portion concave portion 15d receiving the convex portion 24a and / or the protrusion 18a4 receiving the hole 17a2. . Further, in the direction of the arrow, which is the process cartridge mounting direction, the projection 18a4 receives the hole 17a2, thereby preventing the coupling convex portion 17a and the concave portion 18a from being damaged.

  As described above, the rotation accuracy of the coupling drive transmission can be improved, and the positioning of the photosensitive drum shaft in the cross-sectional direction with respect to the apparatus main body during driving and the positioning in the axial direction can be performed with high accuracy.

1 is a side sectional view of an electrophotographic image forming apparatus according to an embodiment of the present invention. It is a sectional side view of the process cartridge which concerns on one Embodiment of this invention. It is a perspective view of a process cartridge according to an embodiment of the present invention. It is a perspective view of a process cartridge according to an embodiment of the present invention. 1 is a perspective view of a process cartridge mounting portion of an electrophotographic image forming apparatus main body according to an embodiment of the present invention. 1 is a perspective view of a process cartridge mounting portion of an electrophotographic image forming apparatus main body according to an embodiment of the present invention. It is a perspective view of the drum flange (drive force transmission component) concerning one embodiment of the present invention. 1 is a perspective view of a photosensitive drum according to an embodiment of the present invention. It is a process cartridge side coupling part sectional view concerning one embodiment of the present invention. It is a coupling part perspective view of the process cartridge which concerns on one Embodiment of this invention. 1 is a cross-sectional view showing a drive system of an electrophotographic image forming apparatus main body according to an embodiment of the present invention. 1 is a cross-sectional view showing a drive system of an electrophotographic image forming apparatus main body according to an embodiment of the present invention. It is a perspective view of the coupling provided in the apparatus main body which concerns on one Embodiment of this invention, and the coupling provided in the process cartridge. It is a perspective view of the coupling provided in the apparatus main body which concerns on one Embodiment of this invention, and the coupling provided in the process cartridge. It is sectional drawing showing the structure of the cover of the apparatus main body which concerns on one Embodiment of this invention, and a coupling part. It is a side view showing the structure around the coupling concave axis at the time of the process cartridge drive of the apparatus main body which concerns on embodiment of this invention. It is a side view showing the structure around the coupling concave axis at the time of attachment or detachment of the process cartridge of the main body which concerns on one Embodiment of this invention. It is sectional drawing of the coupling convex part and recessed part which show one Embodiment of this invention. It is sectional drawing of the coupling convex part which shows one Embodiment of this invention. It is a process cartridge side coupling part sectional view concerning one embodiment of the present invention. 1 is a cross-sectional view of an electrophotographic image forming apparatus according to an embodiment of the present invention. It is a perspective view of a coupling convex part and a crevice concerning one embodiment of the present invention. FIG. 4 is a side sectional view and a plan view of a convex shaft of a twisted triangular prism provided in a process cartridge and a concave shaft provided in an apparatus main body according to an embodiment of the present invention. FIG. 4 is a perspective view showing a twisted concave portion having a substantially triangular cross section provided in a process cartridge and a convex portion of a twisted substantially triangular prism provided in an apparatus main body according to an embodiment of the present invention. It is a perspective view which shows the drive mechanism of the coupling shown in FIG. It is explanatory drawing of the interlock mechanism of an opening-and-closing cover and a drive means based on one Embodiment of this invention. It is explanatory drawing of the interlock mechanism of an opening-and-closing cover and a drive means based on one Embodiment of this invention. It is a perspective view of a coupling concave shaft. It is an axial direction sectional view of a coupling convex part and a crevice (showing the state at the time of drive transmission). It is an axial sectional view of a coupling convex part and a crevice (showing the state before engagement of a convex part and a crevice). It is sectional drawing (a state at the time of driving force transmission is shown) around a coupling convex part and a recessed part. It is sectional drawing (a state at the time of a standby is shown) around a coupling convex part and a recessed part. It is sectional drawing (at the time of driving force transmission) around a coupling convex part and a crevice which shows other embodiments. It is sectional drawing of the coupling recessed part which shows other embodiment. It is sectional drawing of the coupling convex part and recessed part which show other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS A Image forming apparatus B Process cartridge 1 Optical system 2 Recording medium 3 Conveying means 4 Transfer roller 5 Fixing means 6 Ejection part 7 (107) Electrophotographic photosensitive drum 8 Charging roller 9 Exposure opening 10 Developing means 11 Cleaning means 12a, 12b, 12c Frame 13 Image forming apparatus main body 13a Main body side contact portion 14 Cover 14a Cover shaft 15 Cartridge attachment / detachment guide member 16 Photosensitive drum flange 16a Gear portion 17 Coupling convex shaft 17a Coupling convex portion 17a2 Hole 17b Protruding portion end surface 18 Coupling Concave shaft 18a Concave portion 18a1 Concave bottom surface 18a4 Protrusion 24 Bearing 24a Bearing projecting portion 25 Flange 30 Motor 34 Gear 35 Outer cam 36 Inner cam 37 Rod 38 Spring 39 Fixing plate

Claims (8)

A motor, an apparatus main body gear that rotates in response to transmission of a driving force from the motor, a twisted main body recess having a polygonal cross section provided substantially coaxially with the apparatus main body gear; and the main body recess An electrophotographic image forming apparatus that forms an image on a recording medium, and is detachably mounted on the apparatus main body. In an electrophotographic photosensitive drum used for a process cartridge to be processed,
A cylinder having a photosensitive layer on its peripheral surface;
A twisted cartridge protrusion provided at one end in the longitudinal direction of the cylinder, the twisted cartridge protrusion engaging with the twisted main body recess when the process cartridge is mounted on the apparatus main body;
A cartridge recess provided in the cartridge protrusion substantially on the same axis as the cartridge protrusion, and the cartridge recess into which the main body protrusion enters when the process cartridge is attached to the apparatus main body;
Having
When the process cartridge is mounted on the apparatus main body, when the main body gear rotates with the main body convex part entering the cartridge concave part and with the cartridge protrusion fitted into the main body concave part, The electrophotographic apparatus is configured such that the rotational force of the main body gear is transmitted to the electrophotographic photosensitive drum via the main body recess and the cartridge protrusion, and the electrophotographic photosensitive drum rotates. Photosensitive drum.   2. The electrophotographic photosensitive drum according to claim 1, wherein an inner surface of the cartridge concave portion is inclined inwardly from the front end side toward the back side.   The electrophotographic photosensitive drum according to claim 1, wherein a hole is provided in a back side of the cartridge recess.   The play is present between the cartridge concave portion and the main body convex portion when the main body convex portion enters the cartridge concave portion. Electrophotographic photosensitive drum.   5. The apparatus according to claim 1, wherein when a rotational driving force is transmitted to the electrophotographic photosensitive drum, the inner peripheral surface of the cartridge concave portion and the outer peripheral surface of the main body convex portion are not in contact with each other. The electrophotographic photosensitive drum according to any one of the above.   6. The electrophotographic photosensitive member according to claim 1, wherein the main body recess has a triangular cross section, and the cartridge protrusion has a substantially twisted triangular prism shape. drum.   The triangular shape is substantially a regular triangular shape, the triangular prism is a substantially twisted regular triangular prism, and a corner portion of the twisted regular triangular prism is a chamfered shape. Electrophotographic photosensitive drum.   The process cartridge is provided with a circular outer wall over the outer peripheral surface of the twisted cartridge protrusion, and the rotational driving force is transmitted to the electrophotographic photosensitive drum when the process cartridge is mounted on the apparatus main body. 8. The apparatus according to claim 1, wherein the outer wall, the apparatus main body concave portion and / or a part of the inner surface of the cartridge concave portion and a part of the outer peripheral surface of the main body convex portion are in contact with each other during standby. The electrophotographic photosensitive drum according to any one of the above.

Images