JP2005215190A - Coupling pin for process cartridge and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coupling pin for a process cartridge which is enhanced in the yielding strength to pulling, more particularly, in strength capable of withstanding (not be pulled out) the vibration and impact exerted thereon in the process of distribution, and which has advantages in management, such as omissibility of stringent management under which a prescribed press-fitting strength is secured, in the periodical sampling inspection of the surface roughness of the coupling pin and the press-fitting strength of the coupling pin. <P>SOLUTION: The process cartridge is detachable from the image forming apparatus body, the process cartridge is constituted so that a 2nd frame for supporting a developing means for developing an electrostatic latent image formed on the electrophotographic photoreceptor drum is rotatably coupled to a 1st frame for supporting an electrophotographic photoreceptor drum, and regarding the coupling pin for the process cartridge arranged at each side part in a longitudinal direction in order to rotatably couple the 2nd frame to the 1st frame, at least a screw is partly formed in the longitudinal direction of the coupling pin. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a process cartridge that can be attached to and detached from an electrophotographic image forming apparatus. Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer), a facsimile machine, a word processor, and the like.

  The process cartridge is a cartridge in which a charging unit, a developing unit, or a cleaning unit and an electrophotographic photosensitive drum are integrally formed, and 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 main body of the image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive drum are integrated into a cartridge so that it can be attached to and detached from the image forming apparatus main body.

  The present invention further relates to a connecting pin for rotatably connecting two frames in the structure of the process cartridge.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, the electrophotographic photosensitive member and the process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge so that the cartridge can be attached to and detached from the main body of the image forming apparatus. A process cartridge is used. According to this process cartridge system, the apparatus can be maintained by the user himself / herself without depending on the service person, so that usability is remarkably improved.

  As a typical configuration of such a process cartridge, there is one that couples two frames (see Patent Document 1). For example, a cleaning frame that supports a photosensitive drum, a charger, and a cleaning device, a frame that joins a developing frame that supports a developing unit, and a toner frame that has a toner chamber develop a cleaning frame. A frame body in which the frame body and the toner frame body are coupled to each other so as to be rotatable about a coupling pin. Then, both frame bodies are urged around the fulcrum by an elastic member such as a spring to determine the relative position between the photosensitive drum and the developing means.

  The functional advantages of adopting the above-described configuration include optimization of the pressure applied by the developing roller to the photosensitive drum, maintenance of the distance between the photosensitive drum surface and the developing roller surface, and the other is divided into two. Thus, there are many merits such as easy frame forming and easy assembly.

JP-A-8-305252

  The present invention is a further development of the prior art described below. The functional advantages of the present invention include an improvement in pulling-out strength of the coupling pin, particularly an improvement in strength that can withstand vibrations and shocks applied during physical distribution processes, and a management advantage such as the surface roughness of the coupling pin. An object of the present invention is to provide a process cartridge coupling pin and a process cartridge that can omit strict management so as to ensure a predetermined press-fit strength, such as a periodic sampling inspection of the press-fit strength.

  In order to achieve the above object, a first aspect of the present invention is a first frame that is detachably attached to an image forming apparatus main body and supports an electrophotographic photosensitive drum, and an electrostatic formed on the electrophotographic photosensitive drum. A second frame supporting a developing means for developing a latent image is attached to the first frame of a process cartridge in which the second frame is rotatably coupled to the first frame. On the other hand, in the coupling pin of the process cartridge disposed on both sides in the longitudinal direction so that the second frame body is pivotably coupled, the coupling pin is formed with a screw at least in a part in the longitudinal direction. Features.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the connecting pin has a connecting portion to which a tool for rotating the screw is connected.

  According to a third aspect of the present invention, in the second aspect of the present invention, the connecting portion is a groove formed on an end surface of the coupling pin.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the coupling pin has a small-diameter portion at the front in the insertion direction and a large-diameter at the rear in the insertion direction and having a larger outer diameter than the small-diameter portion. And the screw is formed in the small diameter portion.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to third aspects, the coupling pin has a small-diameter portion at the front in the insertion direction and a large-diameter at the rear in the insertion direction and having a larger outer diameter than the small-diameter portion. And the screw is formed in the large diameter portion.

  A sixth aspect of the invention is characterized in that, in the invention of the fourth or fifth aspect, the connecting portion is formed at an end of the large diameter portion.

  The invention according to claim 7 is the invention according to any one of claims 2 to 6, wherein the connecting portion has a shape that can be rotated by a tool only when the screw is rotated in a screwing direction. .

The invention according to claim 8 is the invention according to claim 7, wherein the connecting portion is formed on the side surface of the end portion of the coupling pin, and the downstream side in the direction in which the screw is screwed is a step, 8. The process cartridge coupling pin according to claim 7, wherein the side is an inclined surface.
The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the screw is a tapping screw.

  According to a tenth aspect of the present invention, there is provided a first frame body that is detachable from an image forming apparatus main body and supports an electrophotographic photosensitive drum, and an electrostatic latent image formed on the electrophotographic photosensitive drum. In the process cartridge, in which the second frame supporting the developing means is rotatably coupled to the first frame by coupling pins disposed on both sides in the longitudinal direction. The pin is a coupling pin according to any one of claims 1 to 9.

  According to the present invention, as a functional advantage, an improvement in pulling-out strength, particularly an improvement in strength that can withstand vibrations and shocks applied in the physical distribution process (improvement), and as a management advantage, press-fitting into the first frame Strict management can be omitted so as to ensure a predetermined press-fitting strength such as periodic sampling inspection of strength.

  Further, it can be prevented that a general user, a child, or the like pulls out the coupling pin in an interesting manner and divides the cleaning frame and the development frame.

  Next, a preferred embodiment of the present invention will be described.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the short direction of the process cartridge B is a direction in which the process cartridge B is attached to and detached from the apparatus main body 14 and coincides with the conveyance direction of the recording medium. The longitudinal direction of the process cartridge B is a direction intersecting (substantially orthogonal to) the direction in which the process cartridge B is attached to and detached from the apparatus main body 14, is parallel to the surface of the recording medium, and transports the recording medium. It is a direction that intersects (substantially orthogonal) the direction. The left and right with respect to the process cartridge is the right or left when the recording medium is viewed from above according to the recording medium conveyance direction.

FIG. 1 is an explanatory diagram of a configuration of an electrophotographic image forming apparatus (laser beam printer) to which an embodiment of the present invention is applied, FIG. 2 is an external perspective view thereof, and FIGS. 3 to 6 are applied with the embodiment of the present invention. It is drawing regarding a process cartridge. In the following description, the upper surface of the process cartridge B is a surface located on the upper side when the process cartridge B is mounted on the apparatus main body 14, and the lower surface is a surface located on the lower side.
(Electrophotographic image forming apparatus A and process cartridge B)
First, a laser beam printer A as an electrophotographic image forming apparatus to which an embodiment of the present invention is applied will be described with reference to FIGS. FIG. 3 is a side sectional view of the process cartridge B.

  As shown in FIG. 1, the laser beam printer A forms an image on a recording medium (for example, recording paper, OHP sheet, cloth, etc.) by an electrophotographic image forming process. Then, a toner image is formed on a drum-shaped electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum). Specifically, the photosensitive drum 7 is charged by the charging means 8, and then the photosensitive drum 7 is irradiated with laser light corresponding to the image information from the optical means 1, and the latent image corresponding to the image information is applied to the photosensitive drum 7. Form an image. The latent image is developed by the developing means 9 to form a toner image. In synchronization with the formation of the toner image, the recording medium 2 set in the paper feed cassette 3a is reversed and conveyed by the pickup roller 3b, the conveyance roller pairs 3c and 3d, and the registration roller pair 3e.

  Next, the toner image formed on the photosensitive drum 7 of the process cartridge B is transferred to the recording medium 2 by applying a voltage to the transfer roller 4 as transfer means. Thereafter, the recording medium 2 to which the toner image has been transferred is conveyed to the fixing unit 5 by the conveyance guide 3f. The fixing unit 5 includes a driving roller 5c and a fixing roller 5b incorporating a heater 5a. Then, heat and pressure are applied to the passing recording medium 2 to fix the transferred toner image. Then, the recording medium 2 is conveyed by the discharge roller pairs 3g, 3h, 3i and discharged to the discharge tray 6 through the reverse path 3j. The discharge tray 6 is provided on the upper surface of the apparatus main body 14 of the image forming apparatus A.

  The swingable flapper 3k can be operated to discharge the recording medium 2 by the discharge roller pair 3m without going through the reverse path 3j. In the present embodiment, the pickup roller 3b, transport roller pairs 3c, 3d, registration roller pair 3e, transport guide 3f, discharge roller pairs 3g, 3h, 3i and discharge roller pair 3m constitute a transport means 3. .

  On the other hand, as shown in FIGS. 1 and 3, the process cartridge B rotates the photosensitive drum 7 and uniformly charges the surface thereof by applying a voltage to the charging roller 8 as a charging means. Next, a laser beam corresponding to the image information from the optical system 1 is irradiated onto the photosensitive drum 7 through the exposure opening 1e to form a latent image. The latent image is developed by developing means 9 using toner. That is, the charging roller 8 is provided in contact with the photosensitive drum 7 and charges the photosensitive drum 7. The charging roller 8 is driven to rotate by the photosensitive drum 7. The developing unit 9 supplies toner to the developing area of the photosensitive drum 7 to develop the latent image formed on the photosensitive drum 7. The optical system 1 includes a laser diode 1a, a polygon mirror 1b, a lens 1c, and a reflection mirror 1d.

  Here, the developing means 9 sends the toner in the toner container 11A to the developing roller 9c by the rotation of the toner feeding member 9b. Then, the developing roller 9c incorporating the fixed magnet is rotated, and a toner layer to which triboelectric charge is imparted is formed on the surface of the developing roller 9c by the developing blade 9d, and the toner is supplied to the developing region of the photosensitive drum 7. . Then, the toner is transferred to the photosensitive drum 7 in accordance with the latent image, thereby forming a toner image and making it a visible image. Here, the developing blade 9d defines the amount of toner on the peripheral surface of the developing roller 9c and applies a triboelectric charge. Further, a toner stirring member 9e for circulating toner in the developing chamber is rotatably attached in the vicinity of the developing roller 9c.

  Then, a voltage having a polarity opposite to that of the toner image is applied to the transfer roller 4 to transfer the toner image formed on the photosensitive drum 7 to the recording medium 2, and then the residual toner on the photosensitive drum 7 by the cleaning unit 10. Remove. Here, the cleaning means 10 scrapes off the toner remaining on the photosensitive drum 7 by an elastic cleaning blade 10 a provided in contact with the photosensitive drum 7 and collects it in the waste toner reservoir 10 b.

  When the hinge 35a of the opening / closing member 35 provided at the upper right of the apparatus main body 14 shown in FIG. 1 is opened as a fulcrum, guide rails (not shown) are obliquely provided on the right and left sides of the upper right of the apparatus main body 14 from the upper right to the lower left. I can see that.

  On the other hand, as shown in FIG. 4, on the center line of the photosensitive drum 7 of the process cartridge B, the round guide 13m and the round guide 13m fitted in the positioning groove provided at the end of the guide rail on the left and right sides are integrated or separated from the above. A long ridge-shaped posture determining guide 13n fitted to the guide rail is provided. The circular guide 13m and the posture determining guide 13n are inserted into the aforementioned guide rail, and the process cartridge B is mounted on the apparatus main body 14. The process cartridge B can be removed from the apparatus main body 14 by pulling it up from the lower left to the upper right, contrary to the above description.

When the process cartridge B is attached or detached, the protrusion 11c of the concave portion 17 of the upper frame 11a and the protrusion 11c of the lower frame 11b are handled with hand. The toner frame 11 is integrated by welding an upper frame 11a and a lower frame 11b at a joint surface U.
(Process cartridge frame structure)
The process cartridge B according to the present embodiment includes a toner container (toner) that stores toner in a cleaning unit C in which a cleaning unit 10 such as a photosensitive drum 7 and a cleaning blade 10a and a charging roller 8 are attached to a cleaning frame 13. The developing unit D in which the toner frame 11 having the storage portion 11A and the developing frame 12 holding the developing means 9 such as the developing roller 9c are joined by welding at the locations of the reference numerals 701a and 701b is rotated about the connecting pin 22 as a fulcrum. Combined as possible. Then, as shown in FIG. 6, one end portion of the compression coil spring 23 is inserted into the spring abutting portion 13 b of the cleaning frame body 13 and the rod-shaped spring stopper 12 a of the developing frame body 12, and the hole 20 is centered. Thus, the developing frame 12 is urged clockwise to press-contact the photosensitive drum 7 and the spacer rollers 9i at both ends of the developing roller 9c (FIG. 5).
(How to combine the cleaning frame and development frame)
4 to 7 show how the cleaning unit C and the developing unit D are combined. FIG. 4 shows the cleaning frame 13 and the coupling pin 22. As shown in FIGS. 5 and 6, arm portions 19 protrude toward the cleaning frame 13 on both sides in the longitudinal direction of the developing frame 12. Each suspension hole 20 is coaxially provided at the tips of the two arm portions 19 of the developing device frame 12. A hole 13eo is provided in the outer side plate 13a in the longitudinal direction of the cleaning frame 13, and a hole 13ei is provided in an inner side plate 13f arranged slightly larger than the width of the arm portion 19 inside the outer side plate 13a. Yes. The holes 13eo and 13ei are on a straight line in the longitudinal direction, and are parallel to the photosensitive drum 7. The diameter of the hole 13eo is slightly larger than or substantially the same as the diameter of the hole 13ei.

  When the cleaning frame 13 and the developing frame 12 are coupled, the arm 19 of the developing frame 12 of the cleaning frame 13 is inserted between the outer plate 13a and the inner plate 13f of the cleaning frame 13, and the support hole 13e (13ei) is inserted. , 13eo) and the positioning hole 20 of the developing frame 12 are positioned so as to be substantially coaxial, and then the coupling pins 22 are press-fitted from the outside of both side surfaces of the cleaning frame 13. The outer diameter portion of the coupling pin 22 and the inner diameter of the support hole 13ei of the cleaning frame body 13 are tightly fitted, and the outer diameter portion of the coupling pin 22 and the inner diameter of the support hole 13eo and the suspension hole 20 of the developing frame body 12 are in a clearance fit relationship. Therefore, after the coupling pin 22 is press-fitted into the support hole 13ei and the assembly is completed, the developing frame 12 is supported so as to be rotatable around the coupling pin 22, while the coupling pin 22 is attached to the cleaning frame 13. On the other hand, it is locked with a strength that can withstand a certain amount of pull-out load.

  FIG. 7 is a cross-sectional view showing details of a conventional coupling configuration using coupling pins.

  The coupling pin 22 is a cylindrical solid pin made of steel such as stainless steel or non-ferrous metal such as aluminum or brass manufactured by cutting, grinding, or cold forging (cold forming), and has an outer diameter d1. . In the drawing, the arrow a indicates the insertion direction of the coupling pin 22, and the state shown in the figure indicates the state of completion of assembly. That is, the coupling pin 22 is inserted inward from the outside of the side surface of the cleaning frame 13. In the present embodiment, the outer diameter d1 of the coupling pin 22 = φ3.0 mm (tolerance maximum 0 mm, minimum −0.020 mm), the inner diameters of the holes 13 ei and 13 eo, and the suspension hole 20 are φ3.0 mm (tolerance maximum −0. 030 mm, minimum -0.060 mm), φ3.05 mm (tolerance maximum +0.050 mm, minimum 0 mm), φ3.0 mm (JIS D10 tolerance maximum +0.060 mm, minimum +0.020 mm). As a result, the coupling pin 22 is an interference fit in the hole 13ei of the cleaning frame 13 and is press-fitted and locked. On the other hand, the suspension hole 20 of the development frame body is a clearance fit with respect to the coupling pin 22. The coupling pin 22 is pivotally coupled around the shaft.

By the way, in the conventional configuration as described above, if the coupling pin 22 comes out of any one of the holes 13eo and 13ei of the cleaning frame 13, the coupling pin 22 is supported at one end, and the photosensitive drum. 7 and the opposite ends of the developing roller 9c become unstable, so that the desired electrostatic latent image or visible image cannot be obtained, and as a result, the desired image cannot be obtained. Further, if the coupling pin 22 comes out of the suspension hole 20 of the developing device frame 12, the cleaning frame 13 and the developing device frame 12 are separated, and the function as the image forming apparatus cannot be performed.

  Therefore, in order to avoid the above-described problems, conventionally, the outer diameter of the coupling pin 22 and the inner diameter of the hole 13ei are strictly limited so that the press-fitting of the coupling pin 22 and the hole 13ei of the cleaning frame 13 is not lost. It is managed to ensure a predetermined press-fit strength.

  Note that the predetermined press-fitting strength referred to here is, for example, a strength that can withstand (cannot be removed) vibrations and shocks applied in the distribution process after the process cartridge is shipped. That is, in the physical distribution process, a larger vibration or impact is applied than in image formation or user handling, and therefore the physical distribution process is a more severe condition for the disconnection of the coupling pin 22. Therefore, it is necessary to have sufficient pull-out strength against vibrations and shocks generated in the physical distribution process.

  The object of the present invention is to ensure sufficient removal strength of the coupling pin 22 with respect to the holes 13eo and 13ei of the cleaning frame 13 without performing the strict management as described above.

<Embodiment 1>
In order to achieve the above object, a coupling pin 24 as shown in FIGS. 8 and 9 is used as the first embodiment of the present invention. 8 is a perspective view of the coupling pin 24, and FIG. 9 is a side view. 8 and 9, the coupling pin 24 is a cylindrical solid pin made of steel such as stainless steel or non-ferrous metal such as aluminum or brass, as in the prior art, and has a screw 24a formed at one end and the other end. A connecting portion 24c, which is a groove for connecting a tool for screwing or loosening the screw 24a, here a screwdriver, is formed in the portion.

  Reference numeral 24b denotes a straight portion having a uniform outer diameter. FIG. 10 is a cross-sectional view showing the process of incorporating the coupling pin 24. As shown in FIG. The screw 24a of the coupling pin 24 is an M3 tapping screw, and the inner diameter of the hole 13ei may be a relatively rough tolerance hole of φ2.5mm (tolerance maximum 0.1mm, minimum -0.1mm). The inner diameter of 20 was φ3.05 mm (tolerance maximum +0.050 mm, minimum 0 mm) and φ3.0 mm (JIS standard D10 tolerance maximum +0.060 mm, minimum +0.020 mm), respectively, as in the conventional example. The straight portion 24b of the connecting pin 24 also has an outer diameter d1 = φ3.0 mm (tolerance maximum 0 mm, minimum −0.020 mm) as in the conventional example. In FIG. 10, the connecting pin 24 is inserted into the holes 13eo and 20 in this order, and when the tip of the screw 24a reaches the hole 13ei, a screwdriver 25 is connected to the connecting portion 24c and rotated in the direction of arrow a. 24a is screwed in while forming a female screw in the hole 13ei. FIG. 11 shows that this was incorporated.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.

  There is a small-diameter portion 24d having an outer diameter smaller than that of the straight portion 24b on the upstream side in the insertion direction of the coupling pin 24 in FIG. 12 (in this case, the straight portion 24b can be said to be a large-diameter portion with respect to the small-diameter portion 24d). An M2 tapping screw is formed at the tip of 24d.

  On the other hand, in FIG. 13, a hole 13ej having a relatively rough tolerance with a hole diameter φ1.5 mm (tolerance maximum 0.1 mm, minimum -0.1 mm) is provided inside the hole 13ei. The inner diameters of the holes 13 ei and 13 eo were both φ3.05 mm (tolerance maximum +0.050 mm, minimum 0 mm), and the suspension hole 20 was φ3.0 mm (JIS standard D10 tolerance maximum +0.060 mm, minimum +0.020 mm). As in the first embodiment, the coupling pin 24 is inserted in the order of the holes 13eo and 20, and when the tip of the screw 24a reaches the hole 13ej, the minus screwdriver 25 is connected to the connecting portion 24c and the tapping screw 24a is screwed into the hole 13ej. Get in. FIG. 14 shows that this was incorporated. In the present embodiment, since both end portions of the straight portion 24b are respectively fitted in the holes 13ei and 13eo, the position of the coupling pin 24 with respect to the cleaning frame body 13 can be performed with higher accuracy. In other words, both ends of the straight portion 24b are accurately positioned with respect to the cleaning frame 13 by fitting both ends of the straight portion 24b into the holes 13ei and 13eo, and the tapping screw 24a is screwed into the hole 13ej to prevent it from coming off.

<Embodiment 3>
Next, a third embodiment of the present invention will be described with reference to FIGS.

  15, there is a large diameter portion whose outer diameter is larger than that of the straight portion 24b on the downstream side in the insertion direction of the connecting pin 24, and an M4 tapping screw 24a is formed in the large diameter portion (in this case, the tapping screw 24a). The straight portion 24b can also be said to be a small diameter portion with respect to the large diameter portion that also serves as a).

  On the other hand, in FIG. 16, a hole 13ep having a relatively rough tolerance with a hole diameter of 3.5 mm (tolerance maximum 0.1 mm, minimum -0.1 mm) is provided outside the hole 13eo. The inner diameters of the holes 13 ei and 13 eo were both φ3.05 mm (tolerance maximum +0.050 mm, minimum 0 mm), and the suspension hole 20 was φ3.0 mm (JIS standard D10 tolerance maximum +0.060 mm, minimum +0.020 mm). As in the first embodiment, the coupling pin 24 is inserted in the order of the holes 13eo and 20, and when the tip of the screw 24a reaches the hole 13ep, the minus driver 25 is connected to the connecting portion 24c and the tapping screw 24a is screwed into the hole 13ep. Get in. FIG. 17 shows that this was incorporated.

  In the present embodiment, both ends of the straight portion 24b are fitted into the holes 13ei and 13eo, respectively, as in the second embodiment, so that the position of the coupling pin 24 with respect to the cleaning frame 13 can be performed with higher accuracy. In other words, both ends of the straight portion 24b are accurately positioned with respect to the cleaning frame 13 by fitting both ends of the straight portion 24b into the holes 13ei and 13eo, and the tapping screw 24a is screwed into the hole 13ep to prevent it from coming off.

  Since the coupling pin 24 is coupled to the cleaning frame 13 using a tapping screw as in the above-described embodiment, the pull-out strength against vibration and impact generated in the physical distribution process is remarkably improved as compared with the press-fitting, and the hole 13ei. Since the press-fitting strength is not affected by slight variations in the inner diameter and the outer diameter of the straight portion 24b, it is not necessary to strictly manage these dimensions.

  By the way, although the connecting pin 24 is screwed in with the minus driver in the above-described embodiment, this means that the connecting pin 24 can be easily removed by turning the screw with the minus driver. In the conventional example, since the connecting pin 22 is press-fitted, it is difficult to remove it with a general-purpose tool such as a screwdriver. In other words, in the embodiment of the present invention, the pull-out strength against vibration and impact is remarkably improved, but if the coupling pin 24 is intentionally removed, it can be easily removed with a general-purpose tool such as a flat-blade screwdriver. In the conventional example, it is necessary to strictly control the outer diameter of the coupling pin 24 and the inner diameter of the fitting hole in order to ensure the pulling strength against vibrations and shocks. Even with such a tool, since the rear end portion in the insertion direction of the coupling pin 22 is located inside the outer plate 13a of the cleaning frame 13, the coupling pin 22 cannot be grasped with those tools and cannot be easily removed.

  If a general user or a child with little knowledge of the electrophotographic image forming apparatus pulls out the coupling pin and divides the cleaning frame 13 and the developing frame 12 by interest, the photosensitive drum 7 and the developing roller are separated. There is a risk of scratching the 9c or causing foreign matter such as dust to adhere to the photosensitive drum 7 or the developing roller 9c. Applicants are also cautioned not to disassemble the process cartridge or the instruction manual of the electrophotographic image forming apparatus.

  Further, in the present invention, in order to prevent such a situation, a connection portion that can be screwed in as shown in FIG. 18 but is difficult to loosen is included. 18 has two steps 24c1 parallel to the longitudinal direction (perpendicular to the radial direction) and in opposite directions to each other. The step 24c1 is on the upstream side in the direction in which the screw 24a is screwed in. When the screw 24a of the coupling pin 24 is screwed in, the flathead screwdriver hits the step 24c1, so that it can be screwed in, but when the screw 24a is loosened, That is, there is no step on the downstream side in the screwing direction, and instead the taper surface 24c2 is provided. Such an arrangement prevents the user from separating the cleaning frame 13 and the developing frame 12 by pulling out the coupling pin.

  Although the tapping screw has been described as an example of the screw 24a in the above-described embodiment, it is not limited to the tapping screw, and when the bit insert is embedded in the holes 13ei and 13eo, a small screw corresponding thereto may be used. Moreover, although the groove | channel corresponding to a minus driver was made into the example in the connection part 24c, the cross-shaped groove | channel corresponding to a plus driver may be sufficient, and the shape corresponding to a hexagon wrench may be sufficient. And in order to prevent the user from pulling out the coupling pin with interest, it may be a shape corresponding to a dedicated tool instead of a general-purpose tool such as a screwdriver, or even a shape corresponding to a general-purpose tool is sealed with an adhesive or the like. You may do it. Further, the thickness and outer diameter and tolerance of the hollow pin, the inner diameter and tolerance of the holes 13ei and 13eo of the cleaning frame 13, and the inner diameter and tolerance of the suspension hole 20 of the developing frame 12 are the numerical values of the above-described embodiment. It is not limited.

  The present invention is applicable to a coupling pin for joining two frame bodies of a process cartridge and a process cartridge in which the two frame bodies are coupled by the coupling pin.

1 is a longitudinal sectional view of an image forming apparatus main body according to an embodiment of the present invention. 1 is an external perspective view of an image forming apparatus main body according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the process cartridge which concerns on embodiment of this invention. It is a perspective view which shows the cleaning unit which concerns on embodiment of this invention. It is a perspective view which shows the image development unit which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the coupling | bond part of the frame of a process cartridge. It is a horizontal sectional view which shows the frame coupling | bond part which concerns on the conventional embodiment. It is a perspective view which shows the coupling pin which concerns on Embodiment 1 of this invention. It is a side view which shows the coupling pin which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the insertion process of the coupling pin which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the coupling | bonding state of the coupling pin which concerns on Embodiment 1 of this invention. It is a side view which shows the coupling pin which concerns on Embodiment 2 of this invention. It is a hole sectional view of a frame with which a connecting pin concerning Embodiment 2 of the present invention fits. It is sectional drawing which shows the coupling | bonding state of the coupling pin which concerns on Embodiment 2 of this invention. It is a side view which shows the coupling pin which concerns on Embodiment 3 of this invention. It is a hole sectional view of a frame with which a connecting pin concerning Embodiment 3 of the present invention fits. It is sectional drawing which shows the coupling | bonding state of the coupling pin which concerns on Embodiment 3 of this invention. It is a perspective view which shows the Example of a connection part with the tool of the coupling pin which concerns on this invention.

Explanation of symbols

A Image forming apparatus B Process cartridge C Cleaning unit D Development unit U Joint surface 1 Optical system
DESCRIPTION OF SYMBOLS 1a Laser diode 1b Polygon mirror 1c Lens 1d Reflection mirror 1e Exposure opening part 2 Recording medium 3 Conveyance means 3a Paper feed cassette 3b Pickup 3c, 3d Conveyance roller pair 3e Registration roller 3f Conveyance guide 3g, 3h, 3i Discharge roller pair 3j Reverse path 3k flapper 3m discharge roller pair 4 transfer roller 5 fixing means 5a heater 5b fixing roller 5c driving roller 6 discharge tray 7 photosensitive drum 8 charging roller 9 developing means 9b toner feeding member 9c developing roller 9e toner stirring member 10 cleaning means 10a elastic cleaning Blade 10b Waste toner reservoir 11 Toner frame 11A Toner container 11a Upper frame 11b Lower frame 11c Projection 12 Development frame 12a Spring stopper 13 Cleaning frame 13a Outer plate 13b Abutting portion 13e Support hole portion 13ei, 13eo hole 13f Inner plate 13g Bracket 13h Rib 13m Round guide 13n Posture determining guide 13x End surface 13z Thermal welding portion 14 Device body 17 Recessed portion 19 Arm portion 20 Suspension hole 20a Counterbore portion 22 (Conventional) Coupling pin 23 Compression coil spring 24 Coupling pin (of the present invention) 24a Screw 24b Straight part 24c Connection part 24c1 Step 24c2 Taper part 25 Minus screwdriver 35 Opening / closing member 35a Hinge 701a, 701b

Claims (10)

  A first frame that is detachable from the main body of the image forming apparatus and supports the electrophotographic photosensitive drum, and a second frame that supports the developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive drum. A process cartridge in which the second frame is pivotally coupled to the first frame, and the second frame is pivotally coupled to the first frame. The process cartridge coupling pin arranged on both sides in the longitudinal direction, wherein the coupling pin is formed with a screw at least partially in the longitudinal direction.   2. The coupling pin of a process cartridge according to claim 1, wherein the coupling pin has a connection portion to which a tool for rotating the screw is connected.   3. The coupling pin of a process cartridge according to claim 2, wherein the connecting portion is a groove formed on an end surface of the coupling pin.   The coupling pin has a small-diameter portion at the front in the insertion direction, a large-diameter portion at the rear in the insertion direction and having an outer diameter larger than the small-diameter portion, and the screw is formed in the small-diameter portion. The coupling pin of the process cartridge according to claim 1.   The coupling pin has a small-diameter portion at the front in the insertion direction, a large-diameter portion at the rear in the insertion direction and having a larger outer diameter than the small-diameter portion, and the screw is formed in the large-diameter portion. The coupling pin of the process cartridge according to claim 1.   6. The process cartridge coupling pin according to claim 4, wherein the connecting portion is formed at an end of the large diameter portion.   7. The process cartridge coupling pin according to claim 2, wherein the connecting portion has a shape that can be rotated by a tool only when the screw is rotated in a screwing direction.   The said connection part is formed in the edge part side surface of the said connection pin, The step direction in which the said screw is screwed in becomes a level | step difference, The upstream side is a slope, The upstream is characterized by the above-mentioned. Process cartridge coupling pin.   9. The process cartridge coupling pin according to claim 1, wherein the screw is a tapping screw. A first frame that is detachable from the main body of the image forming apparatus and supports the electrophotographic photosensitive drum, and a second frame that supports the developing means for developing the electrostatic latent image formed on the electrophotographic photosensitive drum. In a process cartridge in which the second frame body is rotatably coupled to the first frame body by coupling pins disposed on both sides in the longitudinal direction.
The process cartridge according to claim 1, wherein the connection pin is the connection pin according to claim 1.

Images