JP3315533B2 - Rotary body support mechanism, process cartridge, and image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support mechanism for a rotating body which makes it easy to attach and detach the rotating body, a process cartridge using an image carrier as the rotating body, and an image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer, a latent image is formed by selectively exposing an image carrier uniformly charged by a charger to a latent image, and the latent image is developed with a developer by a developing device. At the same time, the image is formed by transferring the image formed by the developer onto a recording medium. In such an apparatus, maintenance of each member is performed by a specialized service person, which may be inconvenient for the user.

Therefore, the image carrier, the charger, the developing device,
By cleaning the cleaning unit and the like in a frame and forming a cartridge, the user can load the cartridge into the apparatus main body, thereby replenishing the developer and exchanging parts such as the image carrier that has reached the end of its life. The facilitated one has been put to practical use.

In such a process cartridge, the image carrier is rotatable by a shaft member having a gear flange attached to one end and a flange attached to the other end, and both flanges fixed to a frame. In general, it is configured to support.

Here, as one of the methods of fixing the shaft member to the frame, there is a method of pressing the shaft member into the frame and fixing it. This has the advantage that the play between the frame and the shaft member can be eliminated, and the image quality can be prevented from deteriorating due to the play.

[0006] In addition, since the process cartridge has been increasingly protected in the global environment in recent years, parts are being recycled and reused for the purpose of resource saving, energy saving and reduction of dust.

For example, in a process cartridge, parts such as a charging roller, a developing sleeve, a transfer roller, and other rollers have a long product life and can be used even after the developer in the cartridge is used. Therefore, recently, cartridges after use of the developer have been collected, and components such as the rollers have been taken out and recycled and reused (recycled).

At this time, when removing the image carrier from the frame, it is necessary to pull out the press-fitted shaft member. For this purpose, conventionally, as shown in FIG. 11A, a notch 50a is provided in the shaft member 50, and a tool is hooked on the notch 50a to pull out the shaft member 50 from the frame 51 so that the frame 51 is The image carrier 52 is disassembled.

Further, as shown in FIG.
There is also a configuration in which the image carrier 52 is supported by using the shaft member 53 having a, and when the shaft member 53 is pulled out from the frame 51, the flange 53a is gripped by a tool and pulled out.

[0010] Further, as shown in FIG.
The image carrier 52 is supported by using a shaft member 54 having a perforated hole, and when the shaft member 54 is pulled out from the frame 51, the screw hole 54 is used.
There is also a configuration in which a screw member 55 is screwed into a, and the screw member 55 is pulled out.

[0011]

[Problems to be Solved by the Invention] However, FIG.
In the configuration shown in (a), the shaft member 50 has a notch 50a.
In addition, the notch and its hooked portion cannot be used as the press-fit portion in the press-fit length in the center direction of the shaft member 50, which is disadvantageous for the shaft member 50 to come off. Become.

In the configuration shown in FIG. 11 (b), the diameter of the shaft member 53 is made larger than the inner diameter of the boss hole 51a of the frame body 51 in order to press-fit the shaft member 53, and the outer diameter of the flange 53a is further increased. The diameter R1 has to be larger than the outer diameter R2 of the boss portion, which increases the manufacturing cost of the shaft member 53 and generates a large amount of dust due to processing such as cutting chips.

Further, in the configuration shown in FIG. 11C, since the screw hole 54a is formed in the shaft member 54, the manufacturing cost increases. When the inner surface of the image carrier is grounded,
Normally, a ground plate is brought into contact with the inner surface of the image carrier, the shaft member 54 is brought into contact with the ground plate, and the end surface of the shaft member 54 is brought into contact with a ground electrode of the apparatus main body.
If the screw hole 54a is formed in the hole 54, the earth electrode of the main body of the apparatus may fall into the hole 54a, and a stable earth may not be obtained.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a rotating body support mechanism capable of easily attaching and detaching a rotating body without increasing costs. An object of the present invention is to provide a process cartridge and an image forming apparatus using an image carrier as a rotating body.

[0015]

In order to achieve the above object, a typical configuration according to the present invention is a support mechanism for an electrophotographic photosensitive drum that supports an end of the electrophotographic photosensitive drum with a shaft member. The press-fitting section, comprising: a cylindrical electrophotographic photosensitive drum; a shaft member supporting an end of the electrophotographic photosensitive drum; and a frame having a press-fit portion for press-fitting and fixing the shaft member. A plurality of cutouts provided at an outer end of the plurality of cutouts provided to allow a tool to enter when the shaft member is pulled out from the press-fitting portion and to grip the shaft member by the tool. It is characterized by having a notch.

Further, the process cartridge or the image forming apparatus is constituted by supporting the electrophotographic photosensitive drum on the frame by the above-mentioned structure.

[0017]

In the above structure, when the shaft member pressed into the frame is pulled out, the shaft member can be easily pulled out of the plurality of cutouts by pulling the shaft member with a tool such as pliers.

Further, by providing the notch in the press-fitting fixing portion, it is not necessary to specially process the shaft member, and the cost does not increase.

[0019]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment] As a first embodiment, an image forming apparatus in which a process cartridge can be mounted is described.
A specific description will be given with reference to FIGS. FIG. 1 is a perspective view showing a shaft member for supporting the image carrier and a press-fitting portion of a frame body for press-fitting the same. FIG. 2 is an explanatory view showing a state where the shaft member is pressed into the press-fitting portion. FIG. 4 is an explanatory diagram of a state of an image carrier supported by a shaft member, FIG. 4 is an explanatory diagram of an image forming apparatus in which a process cartridge is mounted, FIG. 5 is an explanatory diagram of a configuration of a process cartridge, and FIG. FIG.

Here, as an order of description, first, the entire configuration of the image forming apparatus in which the process cartridge is mounted will be described with reference to FIGS. 4 to 6, and then, as a rotator, with reference to FIGS. A configuration for supporting the image carrier on the frame will be described.

<< Overall Configuration >> This image forming apparatus A is shown in FIG.
As shown in (1), an optical image based on image information is emitted from the optical system 1 to form an image of a developer (hereinafter, referred to as “toner”) on a photosensitive drum serving as an image carrier. Then, in synchronization with the formation of the toner image, the recording medium 2 is conveyed from the cassette 3a by the conveying means 3 including the pickup roller 3b, the reversing roller 3c, and the pinch rollers 3c1, 3c2, and 3c3 that are pressed against and driven to rotate. And process cartridge B
In the image forming unit formed as a cartridge, the toner image formed on the photosensitive drum is transferred to the recording medium 2 by applying a voltage to a transfer roller 4 as a transfer unit, and the recording medium 2 includes a heater 5a. The recording medium 2 is conveyed to a fixing unit 5 including a fixing rotator 5b and a driving roller 5c that presses and conveys the recording medium 2 to the rotator 5b, and fixes the transferred toner image on the recording medium 2. Then, the recording medium 2 is discharged to the discharge roller pair 3d1, 3d2 and the discharge roller pair 3e1,
The paper is conveyed at 3e2, and is discharged to the discharge unit 7 through the reverse conveyance path 6.

On the other hand, as shown in FIG. 5, the process cartridge B for forming the image forming section rotates a photosensitive drum 8 having a photosensitive layer, and applies a voltage to a charging roller 9 as charging means. The latent image is formed by exposing the light image from the optical system 1 to the photoreceptor drum 8 through an exposure unit to form a latent image, and is developed by the developing unit 10. The developing means 10 sends out the toner in the toner reservoir 10a by a toner sending member 10b,
c, the developing roller 10d is rotated, and a toner layer provided with a triboelectric charge by the developing blade 10e is formed on the surface of the developing roller 10d, and the toner is transferred to the photosensitive drum 8 according to the latent image. As a result, a toner image is formed and a visible image is formed. After the toner image is transferred to the recording medium 2 by applying a voltage having a polarity opposite to that of the toner image to the transfer roller 4, the toner remaining on the photosensitive drum 8 is scraped off by the cleaning blade 11a and scooped by the squeeze sheet 11b. Take, waste toner reservoir
The cleaning unit 11 that collects toner on the photosensitive drum 8 removes residual toner on the photosensitive drum 8. still,
Each component such as the photoconductor drum 8 includes an upper frame 12 and a lower frame 13.
Are housed in a housing in which the cartridges are combined with each other to form a cartridge, and are detachably mounted on a cartridge mounting means provided on the apparatus main body 14.

The cartridge mounting means includes an opening / closing member 14.
When a is opened, a cartridge mounting space is provided as shown in FIG. 6, and a cartridge mounting guide portion 15 is provided on the left and right inner side surfaces of the apparatus main body 14. This left and right guide part 15
A first guide rail 15a and a second guide rail 15b for inserting the process cartridge B are provided to face each other. On the other hand, both outer surfaces of the process cartridge B protrude outward from the rotation center position of the photosensitive drum 8, and
A columnar projection 15c having substantially the same radius as the groove 15a1 provided at the end of the guide rail 15a is provided, and a guide ridge 15d is provided continuously to the columnar projection 15c. Further, an engaging portion 15 is provided at a lower front portion in the insertion direction of the process cartridge B.
e is provided.

When the process cartridge B is mounted, the cylindrical projection 15c and the guide ridge 15d of the process cartridge B are guided by the first guide rail 15a, and the engaging portion 15e is guided by the second guide rail 15b. Then, the process cartridge B is mounted on the image forming apparatus A by closing the opening and closing member 14a.

{Structure of Supporting Photosensitive Drum on Frame} The photosensitive drum 8 is attached to the lower frame 13,
Next, a configuration in which the photosensitive drum 8 as a rotating body is rotatably attached to the frame 13 will be described with reference to FIGS.

As shown in FIG. 3, the photosensitive drum 8 has flanges at both ends of an aluminum cylinder having a photosensitive layer formed on the peripheral surface.
The gears 16a and 16b are fixed to each other by a method such as bonding or caulking, and one flange 16a is provided with a gear portion 16a1. When the process cartridge B is mounted on the apparatus main body 14, the gear portion 16a1 meshes with a drive gear of the apparatus main body 14, and the photosensitive drum 8 rotates upon receiving a driving force from the apparatus main body 14 during image formation. The other flange 16b
A ground plate 18 is provided in contact with the inner peripheral surface of the drum 8 and is configured to be grounded via one shaft member 19.

The flanges 16a and 16b are formed with holes 16c through which the shaft member 19 is inserted. Further, the frame 13 is provided with a press-fit portion 20 for press-fitting and fixing the shaft member 19. Accordingly, the shaft member 19 can be press-fitted into the press-fitting portion 20 and fixed, and can be rotatably supported on the frame 13 by being inserted into the holes 16c of the flanges 16a and 16b. At this time, as shown in FIG.
The tip of 19 is in contact with the ground plate 18, and the photosensitive drum 8 can be grounded via the shaft member 19.

As shown in FIGS. 1 and 2, the press-fitting portion 20 has a cylindrical portion at which the shaft member 19 is press-fitted, and the inner diameter thereof is set slightly smaller than the outer diameter of the shaft member 19. is there. For this reason, when the shaft member 19 is press-fitted into the press-fitting portion 20, it is securely fixed. At the outer end of the press-fit portion 20, a plurality of (in this embodiment, two symmetrical positions) cutouts 20a are provided, and as shown in FIG. Even if it is press-fitted, it is exposed from the notch 20a. Therefore, when disassembling the used process cartridge B,
Alternatively, if the photosensitive drum 8 is damaged when it is assembled and needs to be replaced, the notch 20a
The shaft member 19 can be easily pulled out from the press-fitting portion 20 without damaging the frame 13 by inserting a tool such as pliers into the shaft member 19 and pulling it.

As described above, by providing a plurality of cutouts in the press-fitting portion of the frame into which the shaft member is press-fitted, when the shaft member press-fitted into the press-fitting portion is pulled out, pliers or the like are removed from the cutouts. By pulling the shaft member with a tool, it can be easily pulled out. Further, by providing the notch in the press-fitting portion, it is not necessary to specially process the shaft member, and the cost does not increase.
Therefore, the rotating member can be easily attached to or detached from the frame, and if the photosensitive drum is attached as described above, the photosensitive drum can be separated without damaging the frame. The photosensitive drum can be easily replaced, and the process cartridge can be efficiently recycled.

[Other Embodiments] In the above-described first embodiment, an example is shown in which two notches are provided as a plurality of notches provided in the press-fitting portion. However, the number is not limited to two. At this time, in order to sandwich the shaft member with a tool such as pliers, it is preferable to arrange an even number of notches at symmetric positions.

In the above-described first embodiment, an example is shown in which the grounding plate 18 is attached to the flange 16b and the shaft member 19 is brought into contact with the grounding plate 18 as the structure for grounding the photosensitive drum 8 (FIG. As shown in FIG. 7, an earth plate 18 is attached to a flange 16a having a gear portion 16a for receiving drive transmission, and a shaft member 19 is brought into contact with the earth plate 18 so that the photosensitive drum 8 is earthed. You may.

As shown in FIG. 8, a flange 22 for mounting the ground plate 21 and a shaft member for supporting the flange 22 are provided.
And 23 may be integrally formed by a synthetic resin member.
Even in this case, by providing a plurality of notches 20a in the press-fit portion 20 of the other flange 16a, the shaft member 19
Can be easily removed, and the photosensitive drum 8 is
Can be separated from

In the first embodiment described above, the shaft member 19 is a straight shaft. However, as shown in FIGS.
A stepped shaft 24 having a head 24b larger than 24a may be used. When the stepped shaft 24 is used as the shaft member in this manner, for example, a shaft member (the stepped shaft) on the side where the photosensitive drum 8 is grounded.
Even if there is a slight displacement between 24) and the earth electrode 25 of the apparatus main body, the contact surface of the shaft member is large, so that both are securely contacted and properly grounded. In this case, as shown in FIG. 10, if the shape of the press-fitting portion 20 is set to a stepped shape corresponding to the shape of the stepped shaft 24, the press-in and pull-out of the shaft member can be performed more easily.

In the first embodiment, the photosensitive drum 8 supported by the shaft member has been described as an example in which the photosensitive drum 8 is formed as a separate process cartridge B from the apparatus main body 14. The present invention can be similarly applied to an image forming apparatus in which the photosensitive drum 8 and developing means are directly mounted on the apparatus main body without forming the drum 8 as a cartridge. That is, when the photosensitive drum 8 needs to be replaced, a plurality of cutouts are provided in the press-fitting portion of the frame body for press-fitting the shaft member supporting the photosensitive drum 8 as described above. The drum 8 can be easily removed and can be easily replaced.

In the first embodiment described above, the photosensitive drum 8 is exemplified as a member rotatably supported by the shaft member. However, the rotating member is not limited to this. Thus, the shaft member may be rotatably supported.

The image carrier is not limited to the photosensitive drum, but includes, for example, the following. First, a photoconductor is used as the photoconductor, and as the photoconductor, for example, amorphous silicon, amorphous selenium,
Examples include zinc oxide, titanium oxide, and organic photoconductor (OPC). The shape on which the photoconductor is mounted includes, for example, a rotating body such as a drum or a belt, and a sheet. In general, a drum-shaped or belt-shaped one is used. For example, in the case of a drum-type photoconductor, a photoconductor is deposited or coated on a cylinder of an aluminum alloy or the like. It is.

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

As for the structure of the charging means, the so-called contact charging method is used in the first embodiment described above. However, as another structure, a metal shield such as aluminum is provided around three sides of a conventionally used tungsten wire. It is a matter of course that a configuration may be used in which positive or negative ions generated by applying a high voltage to the tungsten wire are moved to the surface of the photosensitive drum, and the surface of the drum is uniformly charged.

The charging means may be of a blade type (charging blade), a pad type, a block type, a rod type, a wire type, or the like, in addition to the roller type.

As a method of cleaning the toner remaining on the photosensitive drum, the cleaning means may be constituted by using a blade, a fur brush, a magnetic brush or the like.

The process cartridge described above is
It is provided with, for example, an electrophotographic photosensitive member as an image carrier, and at least one of processing means. Therefore, as a mode of the process cartridge, in addition to the above-described embodiment, for example, the image carrier and the charging unit are integrally formed into a cartridge and can be attached to and detached from the apparatus main body. A cartridge in which the image carrier and the developing means are integrated into a cartridge, and which is detachable from the apparatus main body. A device in which the image carrier and the cleaning means are integrally formed into a cartridge and can be attached to and detached from the apparatus main body. Further, there is a type in which an image carrier and two or more of the above-mentioned process means are combined into a cartridge to be detachable from the apparatus main body.

That is, the above-mentioned 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 into a cartridge, and this cartridge is detachable from an 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 so that the cartridge 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 member are integrally formed into a cartridge so as to be detachable from the apparatus main body.

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

[0045]

As described above, the present invention has a shaft member for supporting the end of the rotating body, and a frame having a press-fit portion for press-fitting and fixing the shaft member. A plurality of notches provided at an end portion, when pulling out the shaft member from the press-fitting portion, a tool is made to enter, and a plurality of notches provided for grasping the shaft member by the tool are provided. By having, when pulling out the shaft member of the photosensitive drum press-fitted into the press-fitting portion, a tool such as pliers can be made to enter from the notch, and the shaft member can be pulled, and the shaft member can be easily pulled out from the press-fitting portion. Can be pulled out.

By providing the notch in the press-fitting portion, it is not necessary to specially process the shaft member, and the cost does not increase.

Therefore, the rotating member can be easily attached to or detached from the frame, and when the image carrier is attached as described above, the image carrier can be separated without damaging the frame. Therefore, the image carrier can be easily replaced, and the process cartridge can be efficiently recycled.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of a shaft member for supporting an image carrier and a press-fitting portion of a frame for press-fitting the shaft member.

FIG. 2 is an explanatory view showing a state where the shaft member is press-fitted into a press-fitting portion.

FIG. 3 is an explanatory diagram of a state of an image carrier supported by the shaft member.

FIG. 4 is an explanatory diagram illustrating a configuration of an image forming apparatus in which a process cartridge is mounted.

FIG. 5 is a diagram illustrating the configuration of a process cartridge.

FIG. 6 is an explanatory diagram of a mounting configuration of a process cartridge.

FIG. 7 is an explanatory view of an embodiment in which an earth plate is attached to a flange provided with a gear.

FIG. 8 is an explanatory view of an embodiment in which a flange to which a ground plate is attached and a shaft member are integrally formed.

FIG. 9 is an explanatory sectional view of an embodiment using a stepped shaft as a shaft member.

FIG. 10 is a perspective explanatory view of an embodiment using a stepped shaft as a shaft member.

FIG. 11 is an explanatory diagram of a conventional technique.

[Description of Symbols] A: image forming apparatus, B: process cartridge, 1: optical system, 2: recording medium, 3: transport means, 3a: cassette,
3b: pickup roller, 3c: reversing roller, 3c1,
3c2, 3c3 ... pinch rollers, 3d1, 3d2, 3e1, 3e2 ...
Discharge roller, 4 transfer roller, 5 fixing means, 5a heater, 5b fixing rotating body, 5c drive roller, 6 reverse transport path, 7 discharge section, 8 photosensitive drum, 9 charging roller, 10: developing means, 10a: toner reservoir, 10b: toner feeding member, 10c: magnet, 10d: developing roller, 10e: developing blade, 11: cleaning means, 11a: cleaning blade, 11b: squeeze sheet, 11c: waste toner reservoir,
12 ... upper frame body, 13 ... lower frame body, 14 ... device body, 14a ... opening / closing member, 15 ... guide part, 15a ... first guide rail, 15b ... second guide rail, 15c ... cylindrical projection, 15d ... convex Article, 15e
... engaging part, 16a, 16b ... flange, 16b ... gear part, 16c
... Hole, 18 ... Ground plate, 19 ... Shaft member, 20 ... Press-fit part, 20a ...
Notch, 21… Ground plate, 22… Flange, 23… Shaft member,
24 ... Stepped shaft, 25 ... Earth electrode

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-257342 (JP, A) JP-A-6-192228 (JP, A) JP-A-50-29943 (JP, A) JP-A-63-1988 4252 (JP, A) Fully open 1981-146214 (JP, U) Fully open 1986-178552 (JP, U) Fully open, 58-13526 (JP, U) Fully open, 61-156718 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 21/16 G03G 21/00 350 F16H 35/02

Claims (6)

(57) [Claims] 1. A rotating body support mechanism for supporting an end portion of a rotating body with a shaft member, wherein: a cylindrical rotating body; a shaft member supporting an end portion of the rotating body; A frame body having a press-fitting portion for: a plurality of notches provided at an outer end of the press-fitting portion, wherein when the shaft member is pulled out from the press-fitting portion, a tool is inserted. And a plurality of cutouts provided for gripping the shaft member with the tool. 2. The support mechanism according to claim 1, wherein the rotating body is an electrophotographic photosensitive drum. 3. An electrophotographic photosensitive drum, a process means acting on the electrophotographic photosensitive drum, and a shaft supporting an end of the electrophotographic photosensitive drum. A member having a press-fitting portion for press-fitting and fixing the shaft member to support the electrophotographic photosensitive drum, and a plurality of cuts provided at an outer end of the press-fitting portion. A process cartridge, comprising: a plurality of cutouts provided to allow a tool to enter when the shaft member is pulled out from the press-fitting portion and to grip the shaft member by the tool. 4. The process cartridge, wherein at least one of a charging unit, a developing unit, and a cleaning unit as the process unit and the electrophotographic photosensitive drum are integrally formed into a cartridge to form a cartridge with respect to an image forming apparatus main body. 2. The process cartridge according to claim 1, wherein the process cartridge is detachable. 5. An image forming apparatus in which a process cartridge is detachable and which forms an image on a recording medium, comprising: an electrophotographic photosensitive drum; a process unit acting on the electrophotographic photosensitive drum; A shaft member for supporting an end of the body drum, and a frame having a press-fit portion for press-fitting and fixing the shaft member for supporting the electrophotographic photosensitive drum, and having a frame outside the press-fit portion. A plurality of notches provided at an end portion, when pulling out the shaft member from the press-fitting portion, a tool is made to enter, and a plurality of notches provided for grasping the shaft member by the tool are provided. Mounting means for mounting the provided process cartridge; transfer means for transferring a developed image formed on the electrophotographic photosensitive drum to a recording medium; and transfer means for conveying the recording medium. An image forming apparatus comprising: a conveying unit. 6. An image forming apparatus for forming an image on a recording medium, comprising: an electrophotographic photosensitive drum; a process unit acting on the electrophotographic photosensitive drum; a shaft member supporting the electrophotographic photosensitive drum; A frame having a press-fit portion for press-fitting and fixing the shaft member; a transfer unit for transferring an image formed on the electrophotographic photosensitive drum to a recording medium; and a conveying unit for conveying the recording medium. A plurality of notches provided at an outer end of the press-fitting portion, wherein when the shaft member is pulled out from the press-fitting portion, a tool is made to enter and the tool is gripped by the tool. Forming apparatus having a plurality of notches provided for the image forming apparatus.