JP3535867B2 - Process cartridge - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge attachable to and detachable from an electrophotographic image forming apparatus. Here, the electrophotographic image forming apparatus is an apparatus that forms an image on a recording medium using an electrophotographic image forming method. Examples of the image forming apparatus include electrophotographic copying machines, electrophotographic printers (for example, laser beam printers, LED printers, etc.), facsimile machines, word processors, and the like.

A process cartridge is a charging means,
The developing unit or the cleaning unit and the electrophotographic photosensitive drum are integrally made into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. Also, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive drum are integrally made into a cartridge which 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 integrally made into a cartridge so as to be attachable to and detachable from the main body of the image forming apparatus.

The invention further relates to the construction of the process cartridge.

[0004]

2. Description of the Related Art In an image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. And a process cartridge is adopted. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself without resorting to a serviceman, so the usability is significantly improved.

As a typical structure of such a process cartridge, there is one in which two frame bodies are combined. For example, a cleaning frame body that supports the photosensitive drum, the charger and the cleaning device, and a frame body that joins the developing frame body that supports the developing means and the toner frame body having the toner chamber are rotatably connected about a fulcrum. To do. An elastic member such as a spring urges both frame members around the fulcrum to determine the relative position between the photosensitive drum and the developing means. The functional advantages of the above configuration are that the pressure applied by the developing roller to the photosensitive drum is appropriate, the distance between the surface of the photosensitive drum and the developing roller is maintained, and the other is divided into two. There are many merits such as facilitating frame molding and facilitating assembly.

[0006]

[0007]

The present invention is a further development of the conventional technique described below. According to the present invention, the structure of the connecting portion of the two frame members can improve the accuracy by facilitating the molding of the frame member and reduce the cost by facilitating the manufacturing of the mold, and firmly attach the connecting pin for connecting the two frame members. The object is to provide a process cartridge to be obtained.

[0008]

A first aspect of the present invention relates to an electrophotographic photosensitive drum and a latent image formed on the electrophotographic photosensitive drum in a process cartridge detachably mountable to the main body of the electrophotographic image forming apparatus. Developing means for developing the image, a first frame body for supporting the electrophotographic photosensitive drum, a second frame body for supporting the developing means, and a first frame body provided on the first frame body. A hole, a second hole provided in the first frame body, and a coupling pin for rotatably coupling the first frame body and the second frame body, wherein the coupling pin is A first shaft portion that is provided on the upstream side in the insertion direction for inserting into the cartridge frame body and press-fits into the first hole to prevent the coupling pin from coming off from the first frame body. And a diameter smaller than the diameter of the first shaft portion, which is provided on the downstream side in the insertion direction. And a press-fitting fitting portion for press-fittingly fitting the second hole to prevent the coupling pin from coming off the first frame, and the press-fitting fitting portion. A second shaft portion that is provided on the upstream side in the insertion direction of the second frame body and that has a clearance hole provided in the second frame body and a clearance fit portion that fits with a clearance fit. The upstream end in the insertion direction is flush with the upstream end in the insertion direction of the first hole, or of the first hole from the upstream end in the insertion direction of the first hole. And a connecting pin that is press-fitted to the inside.

A second invention according to the present application is the process cartridge according to the first invention, wherein the diameter of the press-fitting fitting portion is equal to the diameter of the clearance fit portion.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION [Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Next, a preferred embodiment of the present invention will be described. In the following description, the process cartridge B
The short side direction means that the process cartridge B is the apparatus main body 1
4 is the direction of attachment / detachment to and from the recording medium 4, and coincides with the recording medium conveyance direction. The longitudinal direction of the process cartridge B means
It is a direction that intersects with the direction in which the process cartridge B is attached to and detached from the apparatus main body 14 (a direction that is substantially orthogonal), is parallel to the surface of the recording medium, and is a direction that intersects with the direction in which the recording medium is conveyed (generally orthogonal). . The left and right of the process cartridge refer to the right or left when the recording medium is viewed from above according to the conveyance direction of the recording medium.

FIG. 3 is an explanatory view of the configuration of an electrophotographic image forming apparatus (laser beam printer) to which the embodiment of the present invention is applied, and FIG. 4 is an external perspective view thereof. 5 to 7 are drawings relating to the process cartridge to which the embodiment of the present invention is applied. Further, in the following description, the upper surface of the process cartridge B is a surface located above when the process cartridge B is mounted in the apparatus main body 14, and the lower surface is a surface located below.

(Electrophotographic Image Forming Apparatus A and Process Cartridge B) First, a laser beam printer A as an electrophotographic image forming apparatus to which the embodiment of the present invention is applied will be described with reference to FIGS. 3 and 4. Further, FIG. 5 shows a side sectional view of the process cartridge B.

As shown in FIG. 3, 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 photoconductor drum is charged by the charging means, and then the photoconductor drum is irradiated with laser light corresponding to image information from the optical means to form a latent image corresponding to the image information on the photoconductor drum. Then, the latent image is developed by the developing means to form a toner image. Then, in synchronization with the formation of the toner image, the recording medium 2 set in the paper feeding cassette 3a is picked up by a pickup roller 3b and a conveying roller pair 3.
Reversal conveyance is performed by c 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 a transfer unit. After that, the recording medium 2 on which the toner image is transferred is conveyed to the fixing unit 5 by the conveying guide 3f. The fixing unit 5 includes a driving roller 5c and a heater 5a.
b. Then, heat and pressure are applied to the recording medium 2 passing therethrough to fix the transferred toner image. Then, the recording medium 2 is conveyed by the pair of discharge rollers 3g, 3h, 3i and is discharged to the discharge tray 6 through the reversing path 3j. The discharge tray 6 is provided on the upper surface of the apparatus body 14 of the image forming apparatus A. The swingable flapper 3k may be operated to discharge the recording medium 2 by the discharge roller pair 3m without passing through the reversing path 3j. In the present embodiment, the pickup roller 3b, the pair of conveying rollers 3c and 3d, the pair of registration rollers 3e, the conveying guide 3
f, discharge roller pair 3g, 3h, 3i and discharge roller pair 3
The transport means 3 is constituted by m.

On the other hand, in the process cartridge B, as shown in FIGS. 3 and 5, the photosensitive drum 7 is rotated, and its surface is uniformly charged by applying a voltage to a charging roller 8 as a charging means. Then, a laser beam light corresponding to image information from the optical system 1 is irradiated onto the photosensitive drum 7 through the exposure opening 1e to form a latent image. Then, this latent image is developed by the 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 rotated by the photosensitive drum 7. Further, the developing device 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 has a laser diode 1a, a polygon mirror 1b, a lens 1c, and a reflection mirror 1d.

Here, the developing means 9 is the toner container 1.
The toner inside 1A is rotated by the rotation of the toner feeding member 9b.
It is sent to the developing roller 9c. Then, the developing roller 9c containing the fixed magnet is rotated and the developing blade 9 is rotated.
A toner layer to which a triboelectric charge is applied by d is formed on the surface of the developing roller 9c, and the toner is supplied to the developing area of the photosensitive drum 7. Then, the toner is transferred to the photosensitive drum 7 according to the latent image to form a toner image and visualize it. Here, the developing blade 9d
Defines the amount of toner on the peripheral surface of the developing roller 9c and imparts triboelectric charge. Further, a toner stirring member 9e for circulating the toner in the developing chamber is rotatably attached near 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 cleaning means 1 is used.
The residual toner on the photosensitive drum 7 is removed by 0.
Here, the cleaning unit 10 scrapes off the toner remaining on the photosensitive drum 7 by the elastic cleaning blade 10a provided in contact with the photosensitive drum 7, and collects it in the waste toner reservoir 10b.

When the opening / closing member 35 provided on the upper right of the apparatus body 14 shown in FIG. 3 is opened with the hinge 35a as a fulcrum, guide rails (not shown) are provided on the upper right and left sides of the apparatus body 14 from the upper right to the lower left. It can be seen that it is obliquely installed. Meanwhile, FIG.
As shown in FIG.
On the right and left sides of the center line of the guide rail, there are provided a round guide 13m fitted into a positioning groove provided at the end of the guide rail, and a long ridge-shaped posture determining guide 13n which is fitted to the guide rail integrally with or apart from the round guide 13m. The round guide 13m and the attitude determining guide 13n are inserted into the above-mentioned guide rails, and the process cartridge B is attached to the apparatus main body 14.

Contrary to the above, 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.

When the process cartridge B is attached or detached, the protrusions 11c of the recess 17 of the upper frame 11a and the protrusions 11c of the lower frame 11b are handled by hand. The toner frame 11 has an upper frame 11a and a lower frame 11b welded together at a joint surface U to be integrated.

(Structure of Frame of Process Cartridge) The process cartridge B according to the present embodiment includes a toner frame 11 having a toner container (toner storage portion) 11A for storing toner and a developing means 9 such as a developing roller 9c. The developing unit D in which the developing frame body 12 to be held is joined by welding at the portions 701a and 701b, the photosensitive drum 7, the cleaning means 10 such as the cleaning blade 10a, and the cleaning unit C in which the charging roller 8 is attached to the cleaning frame body 13. Are rotatably coupled with the coupling pin 22 as a fulcrum. Then, as shown in FIG. 2, both ends of the compression coil spring 23 are inserted into the rod-shaped spring 13b of the cleaning frame 13 and the rod-shaped spring stopper 13b of the developing frame 12, respectively, and the holes 20 are compressed. The cleaning frame 13 is urged counterclockwise around the center and the developing frame 12 is urged clockwise so that the photosensitive drum 7 and the spacer rollers 9i at both ends of the developing roller 9c are pressed against each other.

(Method of Connecting Cleaning Frame and Developing Frame) FIGS. 1, 2, 6, and 7 show a method of connecting the cleaning unit C and the developing unit D. FIG. 6 shows the cleaning frame 13 and the connecting pin 22.

As shown in FIGS. 2 and 7, arm portions 19 project toward the cleaning frame 13 on both sides of the developing frame 12 in the longitudinal direction. Two arm portions 1 of the developing device frame 12
Each of the hanging holes 20 is coaxially provided at the tip of 9.
A hole 13eo is provided in the outer side plate 13a in the longitudinal direction of the cleaning frame body 13, and the arm portion 1 is provided inside the outer side plate 13a.
Inner plate 13f with a space slightly larger than the width of 9
Is provided with a hole 13ei. Holes 13eo, 13ei
Is on a straight line in the longitudinal direction and is parallel to the photosensitive drum 7. The diameter of the hole 13eo is larger than the diameter of the hole 13ei.

When the cleaning frame body 13 and the developing frame body 12 are combined, the developing frame body 12 of the cleaning frame body 13 is joined.
The arm part 19 of the outer frame 13a of the cleaning frame 13
The inner side plate 13f and the support hole 13e (13e
i, 13eo) and the hanging hole 20 of the developing device frame 12 are positioned so as to be substantially coaxial with each other, and then the coupling pins 22 are press-fitted from outside both side surfaces of the cleaning device frame 13.
The outer diameter portion of the coupling pin 22 and the inner diameter of the support hole 13e (13eo, 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 hanging hole 20 of the developing frame body 12 are loose. Connection pin 22
After press-fitting and assembling, the cleaning frame 13
Is rotatably supported around the coupling pin 22, while the coupling pin 22 is locked to the cleaning frame 13 with a strength that can withstand a pulling load above a certain level.

FIG. 1 is a sectional view showing the details of the coupling structure by the coupling pin.

The connecting pin 22 is a pin made of steel such as stainless steel and non-ferrous metal such as brass manufactured by cutting, grinding or cold forging (cold forming), and has a small diameter portion 22s (diameter d1) and a large diameter portion 22b. (Diameter d2), and the step portion 22d between them has a taper connection. In the figure, an arrow a indicates the insertion direction of the coupling pin 22, and the illustrated state indicates the assembled state. That is, the connecting pin 22 is inserted inward from the outside of the side surface of the cleaning frame 13.

In this embodiment, the small diameter portion 22s of the connecting pin 22 is used.
Diameter d1 = φ3.0 (tolerance maximum 0, minimum −0.0
015) The diameter d2 of the large-diameter portion 22b = φ3.5 (JIS standard m8, tolerance +0.22, minimum +0.004), and the inner diameters of the holes 13ei, 13eo, and 20a are φ, respectively.
3.0 (tolerance maximum -0.040, minimum -0.06
5), φ3.5 (tolerance maximum −0.030, minimum −0.
060), φ3.0 (JIS standard E8 tolerance maximum +
0.028, minimum +0.014).

As a result, the connecting pin 22 becomes a tight fit with the connecting pin small diameter portion 22s and the supporting hole 13ei and the connecting pin large diameter portion 22b and the supporting hole 13eo with respect to the cleaning frame 13, and is press-fitted and locked while the connecting pin small diameter. Since the developing frame suspension hole 20 is a loose fit with respect to the portion 22s, the developing frame 12 is rotatably coupled about the coupling pin 22.
In this coupling method, since the press-fitting locking is performed at the two portions between the cleaning frame body 13 and the coupling pin 22, the drag force against the pulling-out force of the pin increases.

Regarding this configuration, the stepped portion 22a of the coupling pin 22
When the force to press and pull out the connecting pin 22 is measured, it is about 5k
gf, which is a pullout drag force sufficient to prevent the pin from slipping out when the process cartridge B is used.

On the other hand, the press-fitting of the connecting pin 22 is completed at a position where the end face 22c of the connecting pin 22 is deeper than the pin insertion port end face 13x of the cleaning frame 13 as shown in FIG. Alternatively, the end surfaces 13x and 22c are on the same plane. This is the user mistaken
The purpose is to prevent the cleaning unit C and the developing unit D from being separated by pulling out the cleaning unit C. FIG. 8 shows a configuration that more reliably achieves this purpose. As described above, the press-fitting of the connecting pin 22 causes a part of the cleaning frame 13 to be heated and melted to form the heat-welded portion 13z, so that the end 22c of the connecting pin 22 is embedded and the connecting pin 2 is formed.
I try not to pull out 2. Although heat welding is used in the present embodiment, the same configuration can be realized by using vibration, ultrasonic welding, or buildup adhesion with resin.

[Second Embodiment] The second embodiment is shown in FIG.
As shown in FIG.
The diameter of the medium diameter portion 22m is larger than that of s, and the diameter of the large diameter portion 22b is larger than that of the medium diameter portion 22m. The small diameter portion 22s is press-fitted into the hole 13ei of the inner plate 13f of the cleaning frame 13,
b is the hole 13eo of the outer plate 13a of the cleaning frame 13
And presses the medium diameter portion 22m into the arm portion 19 of the developing device frame 12.
It is rotatably fitted in the hanging hole 20 of.

According to this structure, each fitting portion can be freely selected regardless of the axis reference and the hole reference.

[Third Embodiment] FIG. 10 shows a third embodiment. In the third embodiment, holes 13eo, 13 are further provided on the inner side of the inner side plate 13f of the cleaning frame 13 with a space provided therebetween.
A bracket 13g having a hole 13ee concentric with ei is provided. The hole 13ee has a smaller diameter than the hole 13ei.

On the other hand, the coupling pin 22 is provided with a small diameter portion 22s adjacent to the large diameter portion 22b, and a locking portion 22 adjacent to the small diameter portion 22s.
t is provided. The large-diameter portion 22b and the cleaning frame 1
3 is fitted into the hole 13eo of the outer plate 13a, the small-diameter portion 22s and the hanging hole 20 of the arm portion 19 of the developing device frame 12 are loosely fitted, and the locking portion 22t is tapered into the hole 13ee of the bracket 13g. Press fit. The locking portion 22t has, for example, a thick taper on the root side, and further, the large diameter portion 22b and the hole 13eo are tightly fitted, or in addition, the small diameter portion 13s and the hole 13ei are tightly fitted.

According to the third embodiment, the connecting pin 22 is firmly held by the cleaning frame 13.

[0036]

As described above, according to the invention of the present application, a connecting pin for rotatably connecting the first frame body and the second frame body, wherein the connecting pin is Provided on the upstream side in the insertion direction for inserting into the cartridge frame,
The coupling pin is press-fitted into the first hole,
A first shaft portion for preventing it from coming off from the frame body, and a second shaft portion provided on the downstream side in the insertion direction and having a diameter smaller than the diameter of the first shaft portion, A press-fitting fitting portion that is press-fitted into the second hole to prevent the coupling pin from slipping out of the first frame body is provided on the upstream side of the press-fitting fitting portion in the insertion direction. A second shaft portion having a clearance hole provided in the second frame body and a clearance fit portion fitted with a clearance fit, and the upstream end in the insertion direction is the first And a coupling pin flush with the upstream end of the first hole in the insertion direction or press-fitted from the upstream end of the first hole in the insertion direction to the inside of the first hole. Thus, it is possible to prevent the coupling pin from easily coming off the cartridge frame. Further, the second pin can be connected in a favorable rotating state by fitting the connecting pin with a clearance hole provided in the second frame with a clearance fit. Further, since the diameter of the second shaft portion is smaller than the diameters of the first hole and the hanging hole, it is possible to insert the coupling pin into the cartridge frame without resistance. it can.

[Brief description of drawings]

FIG. 1 is a horizontal cross-sectional view showing a frame joint portion according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a configuration of a joint portion of a frame body of a process cartridge.

FIG. 3 is a vertical cross-sectional view of the image forming apparatus main body according to the embodiment of the invention.

FIG. 4 is an external perspective view of the image forming apparatus main body according to the embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of the process cartridge according to the embodiment of the present invention.

FIG. 6 is a perspective view showing a cleaning unit according to an embodiment of the present invention.

FIG. 7 is a perspective view showing a developing unit according to the embodiment of the present invention.

FIG. 8 is a horizontal cross-sectional view showing a frame body coupling portion according to the first embodiment of the present invention.

FIG. 9 is a horizontal sectional view showing a frame body coupling portion according to the second embodiment of the present invention.

FIG. 10 is a horizontal sectional view showing a frame joint portion according to a third embodiment of the present invention.

[Explanation of symbols]

A ... Image forming apparatus B ... Process cartridge C ... Cleaning unit D ... Developing unit U ... Bonding surface 1 ... Optical system 1a ... Laser diode 1b ... Polygon mirror 1c ... Lens 1d ... Reflection mirror 1e ... Exposure opening 2 ... Recording medium 3 ... conveying means 3a ... paper feeding cassette 3b ... pickup 3c, 3d ... conveying roller pair 3e ... registration roller 3f ... conveying guides 3g, 3h, 3i ... discharging roller pair 3j ... reversing path 3k ... flapper 3m ... discharging roller pair 4 ... transfer Roller 5 ... Fixing means 5a ... Heater 5b ... Fixing roller 5c
Drive roller 6, discharge tray 7, photoconductor 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 line 12 ... Development frame 12a ... Spring stop 13 ... Cleaning frame 13a ... Outer plate 13b ... Spring stop 13e ... Support hole 13ei, 13eo, 13
ee ... hole 13f ... inner plate 13g ... bracket 13
m ... Round guide 13n ... Posture determining guide 13x ... End face 13z ... Heat welding part 14 ... Device body 17 ... Recess 19 ... Arm part 20 ... Hanging hole 20a ... Hole 22 ... Coupling pin 22a ... End 22b ... Large diameter part 22
c ... End face 22d ... Step portion 22m ... Medium diameter portion 22s ... Small diameter portion 22t ... Locking portion 23 ... Compression coil spring 35 ... Opening / closing member 35a ... Hinge 701a, 701b ... Location

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-9-26738 (JP, A) JP-A-8-305258 (JP, A) JP-A-8-185108 (JP, A) JP-A-9- 111804 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 21/16-21/18 G03G 15/00 550

Claims (2)

(57) [Claims] 1. A process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus, an electrophotographic photosensitive drum, developing means for developing a latent image formed on the electrophotographic photosensitive drum, and the electrophotographic photosensitive body. A first frame body that supports the drum, a second frame body that supports the developing unit, a first hole provided in the first frame body, and a first frame body that is provided in the first frame body. A second hole and a coupling pin that rotatably couples the first frame body and the second frame body, and is provided on the upstream side in the insertion direction in which the coupling pin is inserted into the cartridge frame body. The first said
And a first shaft portion provided on the downstream side in the insertion direction, the first shaft portion being press-fitted into the hole to prevent the coupling pin from coming off from the first frame body. A second shaft portion having a diameter smaller than the diameter of, and being press-fitted to the second hole to prevent the coupling pin from coming off the first frame, A second hole having a clearance hole provided on the upstream side of the press-fitting fitting portion in the insertion direction and provided in the second frame body and a clearance fitting portion which is fitted by a clearance fit.
And an upstream end in the insertion direction on the same plane as an upstream end in the insertion direction of the first hole, or upstream of the first hole in the insertion direction. And a coupling pin press-fitted from the side end portion to the inside of the first hole. 2. The process cartridge according to claim 1, wherein a diameter of the press-fitting fitting portion is equal to a diameter of the clearance fitting portion.