JP2003295717A - Process cartridge and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge and an image forming device capable of uniformly irradiating a photosensitive body with sufficient light and surely preventing the generation of bad effects to images. <P>SOLUTION: The image forming device is provided with a charge remover for removing the charge of a photosensitive drum after a transfer process and before a charging process. The charge remover consists of a light guide arranged on the process cartridge and a light source arranged on the device body side. The light guide consists of a lens 81 and an external case and a plurality of V-shaped grooves 81a are formed on the lens 81. The grooves 81a are formed at 5 to 15° angles from the diameter direction of the lens 81. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge used in a copying machine, a printer or the like adopting an electrophotographic system, and an image forming apparatus using the process cartridge.

[0002]

2. Description of the Related Art An electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, laser beam printer, LED printer, etc.), a facsimile machine, a word processor, and the like.

A process cartridge is a cartridge in which a charging means, a developing means or a cleaning means and an electrophotographic photosensitive drum are integrally formed, and the cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus. is there. Further, 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 electrophotographic 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 electrophotographic image forming apparatus.

In this type of electrophotographic image forming apparatus, the image carrier uniformly charged by the charging means is selectively exposed to form a latent image on the surface of the image carrier. Then, after the latent image is visualized by the developer (toner) supplied from the developing means, the latent image is transferred to a recording medium, and then the image is fixed by heat or pressure to record an image on the recording medium. There is.

Further, the developer remaining on the image carrier after the transfer is removed by a cleaning means such as a cleaning blade and is stored as a residual developer (removed toner) in the cleaning container, so that the surface of the image carrier is cleaned. The next development can be performed in a state where the developer does not remain.

Among these parts related to image formation, the image carrier, the charging means, the developing means, the cleaning means, etc. are integrally formed and detachably formed into a cartridge in the main body of the image forming apparatus as a process cartridge. It has been put to practical use, and in this case, the user can replace the cartridge by himself. As a result, consumable parts such as the image bearing member and the developer can be replaced without maintenance by a service person.

Among them, the roller contact charging method is preferably used in the charging means from the viewpoint of stabilizing the charging. In the roller charging method, a conductive elastic roller as a charging member is brought into pressure contact with an object to be charged, and a voltage is applied to the object to charge the object to be charged. Specifically, since the charging is performed by discharging from the charging member to the body to be charged, the charging is started by applying a certain threshold voltage abnormal voltage.

As an example, an electrophotography O having a film thickness of about 25 μm
When the charging roller is pressed against the PC photoconductor (member to be charged), the surface potential of the photoconductor starts to rise when a voltage of about 600 V is applied to the charging roller, and thereafter, with respect to the applied voltage. The surface potential of the photoconductor rises proportionally.

Thereafter, this threshold voltage is set to the charging start voltage Vth.
It is defined as That is, in order to obtain the photoreceptor surface potential VD required for electrophotographic image formation, it is necessary to apply a DC voltage corresponding to the charging potential (Vth + VD) to the charging roller. The contact charging method in which only the DC voltage is applied to the contact charging member to charge the body to be charged is called a DC charging method.

By the way, when this DC charging method is used, especially in a low humidity environment, "horizontal stripes generated in a halftone image or the like" caused by disturbance of the surface potential of the photosensitive member before the charging step or before the charging step In some cases, an image adverse effect called "drum positive ghost" or the like caused by the surface potential difference of the photoconductor occurs and becomes a problem.

In order to eliminate such an adverse effect on the image, it is effective to provide a so-called charge elimination means for irradiating the photoreceptor surface with light before the charging step to eliminate the photoreceptor surface potential to a predetermined residual potential level. Known to be.

As shown in FIG. 10, the charge eliminating means includes a charge eliminating device 302 (a chip array in which a plurality of LEDs 303 are arranged, a fuse lamp, etc.) on the photosensitive drum 301.
In general, the main body of the image forming apparatus is provided so as to face the above.

[0013]

However, in the structure in which the conventional static eliminator is arranged in the main body of the image forming apparatus so as to face the photoconductor drum, the static eliminator costs and the static eliminator near the photoconductor drum. However, there are some problems such as restrictions on the design flexibility due to the placement of the.

Particularly in an apparatus having a structure in which the process cartridge is attached to and detached from the main body of the image forming apparatus, it is necessary to consider so that the disposition of the static eliminator does not hinder the attachment and detachment of the process cartridge. Further, there is a problem in that the positional accuracy of the static eliminator and the photosensitive drum deteriorates due to the attachment and detachment of the process cartridge.

Therefore, it is possible to equip the process cartridge with the above-mentioned charge eliminating device. However, in this case as well, the cost is increased by increasing the number of parts of the process cartridge, and it is necessary to provide an electrical contact with the image forming apparatus main body. There is a concern that the device will become complicated and the cost will increase accordingly.

In order to solve such a problem, a light source such as an LED is provided in the image forming apparatus main body, and only the light guide for guiding the irradiation light from the light source to the photosensitive drum side as a linear light is provided in the process cartridge. Proposed.

However, in such a configuration, since the light from the point light source is converted into linear light, it is difficult to irradiate the entire area of the photosensitive drum with a uniform light quantity, and However, it was difficult to increase the light amount of the static elimination light. Therefore, the surface potential of the photoconductor cannot be eliminated to a predetermined residual potential level, and image adverse effects such as "horizontal stripe" and "drum positive ghost" have not been completely prevented.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a process capable of preventing an adverse effect on an image without complicating the apparatus, increasing the cost, and restricting the design. It is to provide a cartridge and an image forming apparatus.

Another object of the present invention is to provide a process cartridge and an image forming apparatus capable of uniformly irradiating a photosensitive member with a sufficient amount of light to surely prevent an image adverse effect.

[0020]

To achieve the above object, the present invention provides a process cartridge which can be attached to and detached from an image forming apparatus main body and includes a charging step, an exposing step, a developing step and a transferring step. A photoreceptor used in a series of image forming processes, and a light guide having a substantially columnar shape, having a plurality of reflecting portions formed side by side in the axial direction on the peripheral surface thereof to guide light introduced from an end surface. A light guide body that is guided by the reflection section to the photoconductor after the transfer step and before the charging step by reflection, and the reflection section is provided so as to be inclined with respect to the radial direction of the light guide body. It is characterized by being

It is preferable that the reflection portion is provided at an angle of 5 to 15 degrees with respect to the radial direction of the light guide.

The reflecting portion is a groove formed on the peripheral surface of the light guide and having a triangular cross section, and the groove length or / and the groove depth of each of the plurality of reflecting portions is the same as the guiding portion. It is preferable that they differ depending on the distance from the end face of the light body.

The image forming apparatus of the present invention is characterized in that the process cartridge is detachably provided.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. In addition,
Here, a full-color laser beam printer will be described as an example of the image forming apparatus, but the present invention is suitable for use in a monochromatic laser beam printer, a copying machine, a laser facsimile, and other electrophotographic image forming apparatuses. is there.

First, the overall structure of the image forming apparatus will be outlined with reference to FIGS. 1 and 2. FIG. 1 is a vertical sectional view showing the overall configuration of a full-color laser beam printer as an image forming apparatus 100 according to this embodiment. FIG. 2 is a vertical cross-sectional view showing a schematic configuration of the process cartridge.

The image forming apparatus 100 shown in the figure has four photosensitive drums 1 (1a, 1b, 1) arranged in parallel in the vertical direction.
c, 1d).

The photosensitive drum 1 is rotationally driven counterclockwise in the figure by a driving means (not shown). Around the photosensitive drum 1, a charging device 2 (2a, 2a) for uniformly charging the surface of the photosensitive drum 1 in order according to the rotation direction thereof.
b, 2c, 2d), a scanner unit 3 (3a, 3b, 3c, 3d) that irradiates a laser beam based on image information to form an electrostatic latent image on the photoconductor drum 1, and toner on the electrostatic latent image. Developing device 4 for adhering and developing as a toner image
(4a, 4b, 4c, 4d), an electrostatic transfer device 5 for transferring the toner image on the photosensitive drum 1 to the transfer material S, and a cleaning device for removing the transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer. 6 (6a, 6b, 6c, 6d) and the like are provided.

Here, the photosensitive drum 1, the charging device 2, the developing device 4 and the cleaning device 6 are integrally formed into a cartridge to form a process cartridge 7.

The photosensitive drums 1 will be described in detail below.

The photosensitive drum 1 is an image bearing member constituted by providing a photosensitive layer on the outer peripheral surface of an aluminum cylinder having a diameter of 30 mm, for example. Both ends of the photosensitive drum 1 are rotatably supported by support members, and a driving force from a drive motor (not shown) is transmitted to one end of the photosensitive drum 1 to rotate counterclockwise in the drawing. Driven.

As the charging device 2, a contact charging type device can be used. The charging member is a conductive roller formed in a roller shape, and this roller is used as the photosensitive drum 1.
It is a charging unit that contacts the surface and applies a charging bias voltage to this roller to uniformly charge the surface of the photosensitive drum 1. Since the reversal developing system is used in this embodiment, the surface of the photosensitive drum 1 is charged with a negative polarity.

The scanner unit 3 is an exposing means arranged substantially in the horizontal direction of the photosensitive drum 1. In the scanner unit 3, a polygon mirror 9 (9a, 9a, 9a, 9a,
9b, 9c, 9d). The image light reflected by the polygon mirror 9 forms the imaging lens 10 (10a, 10b,
10c, 10d) to selectively expose the charged surface of the photosensitive drum 1 to form an electrostatic latent image.

The developing device 4 is a developing means composed of toner containers 41 (41a, 41b, 41c, 41d) respectively containing toners of yellow, magenta, cyan and black.

As shown in FIG. 2, in the developing device 4, the toner agitating / conveying mechanism 42 in the toner container 41 feeds the toner to the toner supplying roller 43 and rotates the toner supplying roller 43 and the developing roller 40 in the clockwise direction in the drawing. Toner is applied to the outer circumference of the developing roller 40 rotating clockwise in the drawing by the developing blade 44 pressed against the toner, and an electric charge is applied to the toner. Then, by applying a developing bias to the developing roller 40 facing the photoconductor drum 1 on which the latent image is formed, toner development is performed on the photoconductor drum 1 according to the latent image.

The electrostatic transfer device 5 as a conveying means faces all the photosensitive drums 1a, 1b, 1c and 1d,
An electrostatic transfer belt 11 that is circularly moved so as to contact with each other is arranged.

The electrostatic transfer belt 11 has a resin film,
A multi-layered film-like member having a resin layer provided on a rubber base layer is used. The electrostatic transfer belt 11 is stretched around a driving roller 13, driven rollers 14a and 14b, and a tension roller 15, and electrostatically adsorbs a transfer material S on the outer peripheral surface on the left side in the figure to the photosensitive drum 1. The transfer material S is circularly moved so as to be in contact with it. As a result, the transfer material S is conveyed to the transfer position by the electrostatic transfer belt 11, and the toner image on the photosensitive drum 1 is transferred.

Abutting on the inside of the electrostatic transfer belt 11,
A transfer roller 12 (12a, 12) as a transfer unit is provided at a position facing the four photoconductor drums 1a, 1b, 1c, 1d.
b, 12c, 12d) are juxtaposed.

A positive polarity bias is applied to these transfer rollers 12 during transfer, and positive polarity charges are applied to the transfer material S via the electrostatic transfer belt 11. Due to the electric field generated at this time, the negative polarity toner image on the photosensitive drum 1 is transferred onto the transfer material S which is in contact with the photosensitive drum 1.

The paper feeding unit 16 is a feeding unit that feeds and conveys the transfer material S to the image forming unit. In the paper feeding section 16, a plurality of transfer materials S are stored in a paper feeding cassette 17.
At the time of image formation, the paper feed roller 18 (half-moon roller) and the registration roller pair 19 are driven and rotated in accordance with the image forming operation, and the transfer materials S in the paper feed cassette 17 are separated and fed one by one. After that, the transfer material S has its tip abutting against the registration roller pair 19 and temporarily stopped to form a loop, and then the rotation of the electrostatic transfer belt 11 and the image writing position are synchronized.
The registration roller pair 19 feeds the sheet onto the electrostatic transfer belt 11.

The fixing section 20 is a fixing means for fixing the toner images of a plurality of colors transferred onto the transfer material S, and includes a rotating heating roller 21a and a pressing member for applying heat and pressure to the transfer material S. The pressure roller 21b.

That is, the transfer material S to which the toner image on the photosensitive drum 1 is transferred is conveyed by the fixing roller pair 21 when passing through the fixing section 20, and at the same time, the fixing roller pair 21.
Gives heat and pressure. As a result, the toner images of a plurality of colors are fixed on the surface of the transfer material S.

In the image forming operation, the process cartridges 7a, 7b, 7c and 7d are sequentially driven in accordance with the print timing, and the photosensitive drum 1 is driven in accordance with the driving.
The a, 1b, 1c and 1d are rotationally driven in the counterclockwise direction. Then, the scanner unit 3 corresponding to each process cartridge 7 is sequentially driven. By this driving, the charging roller applies a uniform charge to the peripheral surface of the photosensitive drum 1 (charging step), and the scanner unit 3 exposes the peripheral surface of the photosensitive drum 1 according to an image signal to expose it. An electrostatic latent image is formed on the peripheral surface of the body drum 1 (exposure step). The developing roller 40 in the developing device 4 transfers the toner to the low potential portion of the electrostatic latent image to form (develop) a toner image on the peripheral surface of the photosensitive drum 1 (developing step).

At the timing when the leading edge of the toner image on the peripheral surface of the most upstream photosensitive drum 1 is rotatably conveyed to the point of opposition to the electrostatic transfer belt 11, the printing start position of the transfer material S is set at the point of opposition. The pair of registration rollers 19 starts rotating to feed the transfer material S to the electrostatic transfer belt 11 so that they coincide with each other.

The transfer material S is pressed against the outer circumference of the electrostatic transfer belt 11 so as to be sandwiched between the electrostatic attraction roller 22 and the electrostatic transfer belt 11. At this time, the electrostatic transfer belt 11
By applying a voltage between the electrostatic attraction roller 22 and the electrostatic attraction roller 22, an electric charge is induced in the transfer material S which is a dielectric and the dielectric layer of the electrostatic transfer belt 11, and the transfer material is moved to the outer periphery of the electrostatic transfer belt 11. It is configured to be electrostatically attracted to. As a result, the transfer material S is stably adsorbed by the electrostatic transfer belt 11 and conveyed to the most downstream transfer unit.

While being conveyed in this manner, the transfer material S sequentially transfers the toner image on each photosensitive drum 1 by the electric field formed between each photosensitive drum 1 and the transfer roller 12 (transfer step). .

The transfer material S on which the four color toner images have been transferred is
Due to the curvature of the belt driving roller 13, the electrostatic transfer belt 11
Are separated from each other by a curvature, and are carried into the fixing unit 20. Transfer material S
After the toner image is heat-fixed by the fixing section 20, the sheet is discharged from the sheet discharging section 24 to the outside of the main body by the sheet discharging roller pair 23 with the image surface facing down.

Next, the process cartridge according to the present embodiment will be described in detail with reference to FIGS.
3 is a perspective view of the process cartridge of FIG. 2, and FIG. 4 is an enlarged view of a main part of FIG. The yellow, magenta, cyan, and black process cartridges 7a,
7b, 7c and 7d have the same structure.

The outer peripheral surface of the bearing member 31 is at a longitudinal position (in the drum axis direction) where it comes into contact with a side plate 74 made of a metal plate which constitutes the main body of the image forming apparatus. The left side plate 74 is provided with abutting surfaces 74a and 74b of the bearing member 31, and abuts the outer peripheral surface of the bearing member 31. As a result, the photosensitive drum 1 is positioned with respect to the side plate 74 via the bearing member 31. Further, the photosensitive drum 1 is pressed against the side plate 74 for positioning. The supporting method on the opposite side in the longitudinal direction of the cartridge is also the same.

The process cartridge 7 has a photosensitive drum 1 which is an image carrier, a photosensitive drum unit 50 having a charging means and a cleaning means, and a developing means for developing an electrostatic latent image on the photosensitive drum 1. It is divided into a developing device (developing unit) 4.

In the photosensitive drum unit 50, the photosensitive drum 1 is rotatably attached to the cleaning frame 51 via the bearing member 31 (bearing) and the conductive shaft member 72.

On the circumference of the photosensitive drum 1, a charging device 2 as a primary charging means for uniformly charging the photosensitive layer provided on the outer peripheral surface of the photosensitive drum 1, and the photosensitive drum 1 after transfer. A cleaning blade 60 is provided for removing the developer (residual toner) remaining on the top.

Further, the residual toner (waste toner) removed from the surface of the photosensitive drum 1 by the cleaning blade 60 is sequentially sent by the toner sending mechanism 52 to the waste toner chamber 53 provided behind the cleaning frame 51.

The developing device 4 comprises a developing roller 40 which contacts the photosensitive drum 1 and rotates in the direction of the arrow Y, a toner container 41 containing toner and a developing frame 45.

The developing roller 40 is rotatably supported by a developing frame 45 via a bearing member, and on the periphery of the developing roller 40, a toner supplying roller 43 which contacts the developing roller 40 and rotates in the arrow Z direction. And the developing blade 44 are arranged respectively. Further, in the toner container 41, a toner stirring / conveying mechanism 42 for stirring the contained toner and conveying it to the toner supply roller 43 is provided.

In the developing device 4, the developing device 4 as a whole swings with respect to the photosensitive drum unit 50 by the pins about the support shafts 49 provided on the bearing members 47 and 48 attached to both ends of the developing device 4, respectively. It has a suspension structure that is movably supported.

In the state where the process cartridge 7 is alone (not mounted in the printer main body), the developing roller 40 causes the developing roller 40 to rotate about the support shaft 49 due to the rotation moment.
The developing device 4 is constantly urged by the pressure spring 54 so as to come into contact with.

At the time of development, the toner contained in the toner container 41 is conveyed to the toner supply roller 43 by the toner stirring / conveying mechanism 42. The toner supply roller 43 rotating in the arrow Y direction supplies the toner to the developing roller 40 by sliding contact with the developing roller 40 rotating in the arrow Z direction, and carries the toner on the developing roller 40.

The toner carried on the developing roller 40 is
As the developing roller 40 rotates, the developing roller 44 reaches the developing blade 44, and the developing blade 44 regulates the toner to form a predetermined thin toner layer, and imparts a desired amount of charge.

The toner thinned on the developing roller 40 is conveyed to the developing section where the photosensitive drum 1 and the developing roller 40 are in contact with each other as the developing roller 40 rotates, and is developed from a power source (not shown) in the developing section. The DC developing bias applied to the roller 40 adheres to the electrostatic latent image formed on the surface of the photoconductor drum 1 to develop the latent image.

The toner remaining on the surface of the developing roller 40 without contributing to the development of the electrostatic latent image is returned to the inside of the developing device as the developing roller 40 rotates, and the toner supply roller 43.
It is separated and collected from the developing roller 40 at the rubbing portion. The collected toner is agitated and mixed with the remaining toner by the toner agitating / conveying mechanism 42.

In the contact developing method in which the photosensitive drum 1 and the developing roller 40 are brought into contact with each other to develop as in the present embodiment, the photosensitive drum 1 is a rigid body, and the developing roller 40 is a surface layer (with the photosensitive drum 1). It is preferable that the contact portion) be an elastic body. As the elastic body, a solid rubber single layer or a solid rubber layer coated with a resin in consideration of charge imparting property to toner is used.

Next, the static eliminator according to this embodiment will be described.

As shown in FIG. 4, the static eliminator has an LED lamp 90 as a light source and a light guide 80. The static eliminator irradiates the surface of the photosensitive drum 1 after the transfer step and before the charging step with static elimination light in the direction of arrow W (see FIG. 2) to eliminate the potential on the photosensitive drum to a predetermined residual potential level. Is a static elimination means for

As a result, it is possible to eliminate horizontal streaks and drum positive ghosts that occur in halftone images and the like. The residual potential here means a saturation potential in the strongly exposed portion, and shows a substantially constant potential regardless of the exposure intensity and the charging potential.

The LED lamp 90 is provided on the image forming apparatus main body side, and is arranged outside the side plate 74 in the photosensitive drum axial direction. The light guide 80 is provided in the process cartridge 7.

The light guide 80 is the electrostatic transfer belt 11
On the downstream side of the drum rotation direction V from the position facing
Further, the cleaning blade 60 is arranged on the upstream side of the photosensitive drum contacting position, and is attached to the cleaning frame 51 using a fixing means such as a double-sided tape.

The axis of the light guide 80 is arranged substantially parallel to the axis of the photosensitive drum 1, and at least one axis end face thereof has a light incident portion 80b for receiving the light emitted from the LED lamp 90.

An LED lamp 90 is attached to a position facing the light incident portion 80b on the image forming apparatus main body side by a mounting means (not shown).
Is attached, and the lighting ON / OFF is performed in synchronization with the driving of the photosensitive drum 1. Also, the LED lamp 90
The side plate 74 between the light guide 80 and the light guide 80 is provided with a light transmission hole 74c.

Next, the structure of the light guide 80 will be described in detail with reference to FIGS.

As shown in the schematic cross-sectional view of FIG. 5, the light guide 80 transmits and reflects the light received from the LED lamp 90 and guides it to the photosensitive drum 1, which is a substantially cylindrical lens 81 as a light guide. And an outer case 82 whose inner surface is white in order to increase the reflection efficiency of the lens 81.

An opening is provided in a portion corresponding to the light incident portion 80b of the outer case 82, and light from the LED lamp 90 is incident on the light incident portion 80b which is the end face of the lens 81. Further, a light irradiation opening 82a corresponding to a width that needs to be neutralized is provided at a position facing the photosensitive drum 1.
The photosensitive drum 1 is irradiated with light.

On the peripheral surface of the lens 81, the light irradiation opening 82
a, that is, at a position opposite to the light irradiation direction W side, as shown in the lens schematic perspective view of FIG. 6, a plurality of V-shaped notches (grooves 81a having a triangular cross section are formed over almost the entire axial direction of the lens 81. ) Are arranged side by side in parallel. This groove functions as a reflecting portion that reflects the light introduced from the light incident portion 80b toward the photosensitive drum 1 side. That is, the two groove surfaces of the groove each form a reflecting surface.

The shape of the groove 81a will be described in detail with reference to FIGS. FIG. 7 is a plan view of the lens 81 and is a view in the X direction of FIG. Further, FIG. 8 is a sectional view taken along line BB of FIG. 7.

As shown in FIG. 7, the groove 81a is formed in the lens 8
It is provided at an angle of 5 to 15 degrees with respect to the radial direction of 1 (angle of 85 to 75 degrees with respect to the axial direction). Accordingly, it is possible to secure a large groove length, that is, a width of the reflecting surface, as compared with a case where the groove is provided in parallel to the radial direction of the lens. Therefore, the reflection efficiency of the lens 81 can be increased, and a sufficient amount of static elimination light can be obtained.

Further, as shown in FIG. 8, each groove 8
1a is formed to have a constant apex angle (A degree) and a constant axial pitch. As a result, the directions of light reflected by the groove surfaces of the grooves 81a are aligned in substantially the same direction.

Further, as shown in FIG. 7, a plurality of grooves 81
The length of each groove of a differs depending on the distance from the end surface of the lens 81. Specifically, the groove length d1 of the groove 81a arranged at both ends of the lens 81 is the smallest, and the groove length becomes longer toward the central portion of the lens 81, and the groove arranged in the central portion of the lens 81. The groove length d2 of 81a is set to be the longest.

That is, the portion of the lens 81 near the light incident portion 80b has a small reflecting surface because the amount of light incident from the LED lamp 90 is large, and the light incident portion 80b is also provided.
Even in a portion near the end surface 80c on the opposite side to the outer case 82
There is a return light reflected on the inner surface of the, so it should be a small reflective surface. Then, the reflecting surface in the central portion of the lens 81 having a small amount of light is enlarged.

As a result, reflected light having a substantially uniform light amount is obtained over the entire area of the lens 81, and the photosensitive drum 1 can be uniformly irradiated.

As described above, according to the configuration of the present embodiment, the photosensitive drum 1 can be uniformly irradiated with a sufficient amount of light, and adverse effects on the image such as horizontal stripes and drum positive ghost can be reliably prevented.

Further, in the present embodiment, the LED lamp 90
Is provided in the apparatus main body outside the process cartridge 7 in the axial direction of the photoconductor drum 1.
The D lamp 90 does not become an obstacle when the process cartridge 7 is attached and detached in the radial direction of the photosensitive drum 1.

Further, in this embodiment, since the photosensitive drum 1 and the light guide 80 are integrally provided in the process cartridge 7, their relative positions may be displaced even when the process cartridge 7 is attached or detached. Therefore, it is possible to perform highly accurate exposure from the light guide 80 to the photosensitive drum 1.

In this embodiment, the LED lamp 90
Is provided on the apparatus main body side, the light source is not wasted even when the process cartridge 7 is replaced, and the cost of the process cartridge 7 can be reduced. Furthermore, the electrical connection between the apparatus main body and the process cartridge can be simplified.

In the above embodiment, the length of the groove 81a of the lens 81 is gradually changed. However, as shown in FIG. 9, for example, the groove depth of each of the plurality of grooves 81a is set to the lens 81. A configuration in which the distance is changed depending on the distance from the end face is also suitable. In the example of FIG. 9, the groove depth A and the groove pitch p of the groove 81a are increased as the distance from the light incident portion of the lens 81 increases. Thereby, the same effect as changing the groove length can be obtained.

Further, in the above embodiment, the light source is provided only at the position facing one end surface of the lens 81, but when the light quantity is insufficient, one light source is provided at each position facing both end surfaces of the lens 81. A plurality of light sources, two in total, may be provided.

[0085]

As described above, according to the present invention,
It is possible to surely prevent the image adverse effect without complicating the apparatus, increasing the cost, and inviting the restriction on the design. Further, it is possible to irradiate the photoconductor uniformly with a sufficient amount of light and reliably prevent the adverse effect on the image.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of a process cartridge according to the embodiment of the present invention.

FIG. 3 is a perspective view of the process cartridge of FIG.

FIG. 4 is a partial perspective view showing a main body configuration of a portion related to the process cartridge and the static eliminator of FIG.

FIG. 5 is a schematic cross-sectional view of a static eliminator according to an embodiment of the present invention.

6 is a schematic perspective view of a lens of the static eliminator shown in FIG.

7 is a plan view of a lens of the static eliminator shown in FIG.

8 is a cross-sectional view taken along line BB of FIG.

FIG. 9 is a side view showing a modified example of the lens of the static eliminator.

FIG. 10 is a schematic perspective view showing a conventional static eliminator.

[Explanation of symbols]

1 (1a, 1b, 1c, 1d) Photosensitive drum 2 (2a, 2b, 2c, 2d) Charging device 3 (3a, 3b, 3c, 3d) Scanner unit 4 (4a, 4b, 4c, 4d) developing device 5 Electrostatic transfer device 6 (6a, 6b, 6c, 6d) Cleaning device 7 (7a, 7b, 7c, 7d) process cartridge 9 polygon mirror 10 Imaging lens 11 Electrostatic transfer belt 12 Transfer roller 13 Belt drive roller 14a, 14b driven roller 15 Tension roller 16 paper feeder 17 Paper feed cassette 18 Paper feed roller 19 Registration roller pair 20 fixing unit 21 Pair of fixing rollers 21a heating roller 21b Pressure roller 22 Electrostatic attraction roller 23 Paper ejection roller pair 24 Paper output section 31 Bearing member 40 developing roller 41 toner container 42 Toner stirring / transporting mechanism 43 Toner supply roller 44 Development blade 45 Development frame 47,48 Bearing member 49 Support shaft 50 Photosensitive drum unit 51 cleaning frame 52 Toner feeding mechanism 53 Waste Toner Room 54 Pressure spring 60 cleaning blade 72 Conductive shaft member 74 Side plate 74a, 74b abutting surface 74c Light transmission hole 80 Light Guide 80b Light incident part 80c end face 81 lens (light guide) 81a groove 82 outer case 82a Light irradiation opening 90 LED lamp 100 image forming apparatus

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yokomori Trunk             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H035 AA11 CA07 CB01                 2H038 AA54 BA01                 2H042 AA02 AA18 AA24 AA29                 2H171 FA02 FA09 FA18 GA01 GA03                       GA04 JA23 JA27 JA29 JA31                       JA32 JA43 QA04 QA08 QB03                       QB15 QB32 QB41 QC03 QC05                       QC07 QC22 QC29 QC32 QC36                       SA11 SA14 SA22 SA26

Claims (4)

[Claims] 1. A process cartridge attachable to and detachable from a main body of an image forming apparatus, comprising a photoconductor to be subjected to a series of image forming processes including a charging step, an exposing step, a developing step and a transferring step, and a substantially cylindrical conductive member. The photoconductor, which has a plurality of reflecting portions formed side by side in the axial direction on its peripheral surface, and reflects the light introduced from the end face by the reflecting portions, thereby performing the exposure after the transfer step and before the charging step. And a light guide body that guides the light guide body to the body, wherein the reflection portion is provided so as to be inclined with respect to a radial direction of the light guide body. 2. The process cartridge according to claim 1, wherein the reflecting portion is provided at an angle of 5 to 15 degrees with respect to a radial direction of the light guide. 3. The reflection part is a groove having a triangular cross section formed on the peripheral surface of the light guide, and the groove length or / and the groove depth of each of the plurality of reflection parts are: The process cartridge according to claim 1, wherein the process cartridge differs depending on the distance from the end face of the light guide. 4. An image forming apparatus comprising the process cartridge according to claim 1, 2, or 3 in a detachable manner.