JP2001100493A - Image forming device and processing cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device and a processing cartridge prevented from the occurrence of abnormal discharge as a result of toner leaking from a developing device, even when paper dust removing means is equipped. SOLUTION: At both end parts outside of the image forming area on a photosensitive drum 20, the cartridge is provided with a grid cover 100 as a separation member, between nonwoven fabric 81 of the paper dust removing device 80 and a part of an electrode 33 of an electrostatic charging device 30. The grid cover 100, for instance, is pasted on a urethane sheet 82 for attaching the nonwoven fabric 81.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and a process cartridge for forming an image by transferring a developer to a recording medium, and more particularly, to an image forming apparatus using a scorotron type or corotron type charger. It belongs to the technical field of a process cartridge.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a laser beam printer, an electrostatic latent image is formed by uniformly charging the surface of a photosensitive drum driven by rotation by corona discharge and exposing the laser beam. Then, the toner is transferred to the electrostatic latent image by the action of an electric field between the developing roller and the photosensitive drum which are driven to rotate, and a toner image is formed on the photosensitive drum. Then, the toner image is transferred to a transfer sheet by the action of an electric field between the transfer roller and the photosensitive drum, and further, the toner image is heated and pressed on the transfer sheet to be fixed on the transfer sheet, thereby forming an image. Is going.

[0003] Therefore, the surface of the photosensitive drum comes into contact with the transfer paper in the transfer step, so that paper dust may adhere to the surface of the photosensitive drum. Therefore, in a conventional image forming apparatus, a paper dust removing unit that rubs against the surface of the photosensitive drum to remove paper dust is provided downstream of the position where the transfer is performed in the rotation direction of the photosensitive drum. .

On the other hand, since the toner for forming the toner image is composed of extremely fine particles having high fluidity, a problem of toner leakage from a developing device having the developing roller is likely to occur. Therefore, in the conventional image forming apparatus, the occurrence of the toner leakage is prevented by bringing the seal member into contact with the peripheral surface of the developing roller which is driven to rotate.

In particular, since toner leakage tends to occur from both ends of the developing roller, both ends of the developing roller are covered with seal members made of sponge, Teflon felt or the like. It is configured to rub.

[0006]

However, in a recent image forming apparatus, a spherical polymerized toner having extremely high fluidity is used for the purpose of forming a higher definition image. Even when the member was provided, toner leakage sometimes occurred in some cases.

Although toner does not originally exist on the surface of the developing roller outside the image forming area, the toner leaks as described above, and as a result, the toner adheres linearly along the rotation direction of the developing roller. Since the toner leaking out in this manner is not provided with a sufficient triboelectric charge, the transfer direction cannot be controlled by the electric field between the photosensitive drum and the developing roller, and the toner should not originally adhere. It is transferred to the surface of the photosensitive drum outside the image forming area. Therefore, the leaked toner on the surface of the photosensitive drum reaches the contact portion between the paper dust removing unit and the photosensitive drum by the rotation of the photosensitive drum, and is accumulated or passed through the contact portion.

When the amount of toner accumulated in the contact portion increases, or when the toner contacts the paper dust removing means when passing through the contact portion, there is a problem that the toner scatters to the outside. there were.

In particular, a charger for performing the above-described corona discharge is provided near the paper dust removing means. When the scattered toner enters the inside of the charger, an abnormal discharge occurs inside the charger. There is a problem that printing is easily caused by this, and various errors occur due to generation of noise.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an image forming apparatus which does not cause abnormal discharge due to toner leaking from a developing device even when a paper dust removing unit is provided. It is an object to provide a process cartridge.

[0011]

According to another aspect of the present invention, there is provided an image forming apparatus comprising: a charger having a corona discharge electrode; and an electrostatic latent image charged to a predetermined potential by the charger. What is claimed is: 1. An image forming apparatus comprising: a carrier; and a paper dust removing unit disposed opposite to the electrostatic latent image carrier, wherein both end positions of the electrostatic latent image carrier outside an image forming area in a longitudinal direction are provided. Wherein a partition member is provided between the charger and the paper dust removing means.

According to the first aspect of the invention, the developer leaked from both ends in the longitudinal direction of the developing device is transferred to both end positions outside the image forming area in the longitudinal direction of the electrostatic latent image carrier. Then, even if the paper dust removing means may be in contact with the electrostatic latent image carrier, a partition member may be provided between the charger and the paper dust removing means at the both end positions. Since it is provided, the developer scattered from the contact portion with the paper dust removing means is reliably prevented from entering the inside of the charger.

According to a second aspect of the present invention, in order to solve the above problem, in the image forming apparatus according to the second aspect, the partition member faces the electrostatic latent image carrier of the charger. It is characterized by being provided so as to protrude to a position covering a part of the part.

According to the image forming apparatus of the present invention, the partitioning member is provided so as to protrude to a position covering a part of the charging device facing the electrostatic latent image carrier. The flying developer is reliably prevented from entering the inside of the charger without adversely affecting the charging action on the electrostatic latent image carrier by the charger.

According to a third aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect, wherein the partition member is formed of an insulating resinous member. It is characterized by.

According to the image forming apparatus of the present invention, the partition member is formed of an insulating resinous member.
Even when it comes into contact with a part of the charger, no discharge or the like is generated and the molding is easy, so that the shape can be processed so as not to adversely affect the paper dust removing action of the paper dust removing means, for example.

According to a fourth aspect of the present invention, there is provided a process cartridge comprising:
In order to solve the above-mentioned problems, a charger having a corona discharge electrode, an electrostatic latent image carrier charged to a predetermined potential by the charger, and a paper dust removal device arranged opposite to the electrostatic latent image carrier And a partition member between the charger and the paper dust removing means at both end positions outside the image forming area in the longitudinal direction of the electrostatic latent image carrier. It is characterized by having.

According to the process cartridge of the present invention, the developer leaked from both ends in the longitudinal direction of the developing device is transferred to both end positions outside the image forming area in the longitudinal direction of the electrostatic latent image carrier. Even if it may come in contact with paper dust removing means arranged opposite to the electrostatic latent image carrier, a partition member is provided between the charger and the paper dust removing means at the both end positions. As a result, the developer scattered from the contact portion with the paper dust removing means is reliably prevented from entering the inside of the charger.

According to a fifth aspect of the present invention, there is provided a process cartridge comprising:
In order to solve the above-mentioned problem, in the process cartridge according to claim 4, the partition member is provided so as to protrude to a position covering a part of a portion of the charger facing the electrostatic latent image carrier. It is characterized by the following.

According to the process cartridge of the present invention, the partition member is provided so as to protrude to a position covering a part of the charging device facing the electrostatic latent image carrier, so that the charging device is provided. Thus, it is possible to reliably prevent the scattered developer from entering the inside of the charger without adversely affecting the charging action on the electrostatic latent image carrier due to the above.

According to a sixth aspect of the present invention, there is provided a process cartridge comprising:
In order to solve the above problem, the process cartridge according to claim 4 or 5, wherein the partition member is formed of an insulating resinous member.

According to the process cartridge of the present invention, since the partition member is formed of an insulating resinous material, even if it comes into contact with a part of the charger, no discharge or the like is generated. Since the molding is easy, for example, the shape can be processed so as not to adversely affect the paper dust removing action of the paper dust removing means.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a schematic configuration of a laser beam printer 1 as an embodiment of the image forming apparatus of the present invention. In FIG. 1, a laser beam printer 1 is
A feeder unit for feeding paper (not shown) is provided at the bottom of the main body case 2. The feeder unit includes a sheet pressing plate 10 urged upward by a spring (not shown),
It includes a paper feed roller 11 and a friction separating member 14 pressed by the paper feed roller 11. The paper stacked on the paper pressing plate 10 is pushed up so as to contact the paper feed roller 11,
By rotating the paper feed roller 11 in the direction of the arrow in FIG. 1 at a predetermined timing, only the uppermost paper is separated and supplied between the paper feed roller 11 and the friction separating member 14.

A pair of registration rollers 12 and 1 are located on the downstream side in the sheet conveyance direction due to the rotation of the paper feed roller 11.
3 is rotatably supported, and conveys a sheet at a predetermined timing to a transfer position formed by a photosensitive drum 20 and a transfer roller 21, which will be described later.

Photosensitive drum 20 as electrostatic latent image carrier
Is made of a positively chargeable material, for example, an organic photoreceptor mainly containing positively chargeable polycarbonate. In particular,
The photosensitive drum 20 has, for example, a cylindrical aluminum sleeve as a main body, and a predetermined thickness (for example, about 20 mm) in which a photoconductive resin is dispersed in polycarbonate on the outer peripheral portion thereof.
μm), and is rotatably supported by the main body case 2 with the cylindrical sleeve grounded. Further, the photosensitive drum 20 is driven to rotate in a direction indicated by an arrow by driving means (not shown).

The charger 30 is, for example, a scorotron type charger for positive charging that generates corona discharge from a charging wire made of tungsten or the like. As shown in FIG. 2 which is an enlarged view of the process cartridge 2 a in FIG. 1, the charger 30 includes a corona wire 31, a shield 32 covering the corona wire 31, and a grid provided so as to face the corona wire 31. In particular, in the present embodiment, the shield 32 and the grid electrode 33 are integrally formed. An opening B is provided in the holding portion 34 of the shield 32. A charge trapping electrode 90 is provided on the shield 32 so as to cover the opening B, and one end of the charge trapping electrode 90 is formed to extend to a paper dust removing device 80 described later.

With this configuration, the opening B
Is directly received by the ions discharged from the corona wire 31 and is charged.

Referring back to FIG. 1, the laser scanner unit 40 includes a laser generator (not shown) for generating a laser beam L for forming an electrostatic latent image on the photosensitive drum 20, and a polygon mirror that is driven to rotate. (Pentahedral mirror) 41, a pair of lenses 42 and 45, and reflection mirrors 43, 44 and 46.

The developing device 50 has a case 51 in which a toner storage chamber 52 as a developer chamber is formed.
An agitator 53 is provided inside 2 so as to be rotatable around a rotation shaft 54. The toner stored in the toner storage chamber 52 is a positively chargeable non-magnetic one-component developer,
A particle size of 6 μm obtained by adding a well-known coloring agent such as carbon black and a charge controlling agent such as nigrosine, triphenylmethane and quaternary ammonium salt to a styrene-acrylic resin formed into a spherical shape by suspension polymerization. It has toner base particles having a particle size of 10 to 10 μm and an average particle size of 8 μm. The toner is configured by adding silica as an external additive to the surface of the toner base particles.

The photosensitive drum 20 in the toner storage chamber 52
On the side, a developing chamber 55 for performing development by communicating with the toner storage chamber 52 through an opening A is formed, and a supply roller 56 and a developing roller 57 are rotatably pivotally supported. The toner on the developing roller 57 is regulated to a predetermined layer thickness by a layer-thickness regulating blade 58 provided with a contact portion made of silicone rubber at the tip of a thin plate-like elastic metal plate, and is used for development.

The transfer roller 21 is pivotally supported rotatably,
It is made of a conductive foamed elastic body made of silicone rubber or urethane rubber. The transfer roller 21 is configured to reliably transfer the toner image on the photosensitive drum 20 to the paper by the applied voltage.

In this embodiment, the photosensitive drum 2
0, a charger 30, a developing device 50, and a transfer roller 21 are provided in a frame, and constitute a process cartridge 2a that is detachable from the laser beam printer 1.
The developing device 50 is configured as a developing device cartridge that is detachable from the process cartridge 2a.

The fixing unit 70 includes the registration roller 12
The heating roller 71 and the pressing roller 72 are provided on the further downstream side in the sheet conveyance direction from the sheet feeding roller 13 to the pressure contact portion between the photosensitive drum 20 and the transfer roller 21. The toner image transferred to the sheet is pressed while being heated and is fixed on the sheet.

A pair of transport rollers 73 for transporting the paper are provided downstream of the fixing unit 70 in the transport direction, and a pair of discharge rollers 7 are located downstream of the transport roller 73.
4 and a paper discharge tray 75 are provided in this order.

Further, as shown in FIG. 2, a paper dust removing device 80 provided as a paper dust removing means provided adjacent to the photosensitive drum 20 has a holder 83 and a base end supported on an upper portion of the holder 83. Urethane sheet 8 covered with non-woven fabric 81 at the tip
2, a brush-like member 86 for scraping paper dust, and a conductive plate 84 that supports the brush-like member 86 and is mounted on a holder 83.

As the non-woven fabric 81, a non-woven fabric integrated by confounding constituent fibers was used. This is because it is preferable to use a constituent fiber having a high degree of freedom in capturing fine paper powder between the fibers. As a constituent material, for example, polyester fiber, polyamide fiber, or the like is used.
The nonwoven fabric 81 is impregnated with an oil agent. Mineral oil, synthetic oil, etc. were used as the oil agent. The nonwoven fabric 81 was formed so as to have a length in the longitudinal direction substantially equal to the length in the longitudinal direction of the photosensitive drum 20, and was adhered to the front end portion of a urethane sheet 82 as a substrate made of a sheet-like member using a double-sided tape.

The urethane sheet 82 is a sheet member made of urethane rubber and has a hardness of 92 ° Hs (J
IS K-6301). Urethane sheet 8
Reference numeral 2 is attached so that the leading end of the urethane sheet 82 is brought into pressure contact with the photosensitive drum 20.

The holder 83 is formed to have substantially the same length as the photosensitive drum 20 in the longitudinal direction of the photosensitive drum 20, and supports both ends in the longitudinal direction of the photosensitive drum 20 with screws (not shown). Screwed to the frame. In addition, a storage room for paper powder is formed inside, and an opening is formed on the side facing the photosensitive drum 20. Further, a urethane film 87 is attached to a lower portion of the holder 83. The base end of the urethane film 87 is attached to the holder 83 by using a double-sided tape, and the free end side is in contact with the photosensitive drum 20. By providing such a urethane film 87, it is possible to prevent paper powder from falling from the storage chamber of the holder 83.

As the brush-like member 86, a sheet on which fibers were planted was used. As shown in FIG. 2, this sheet is made of a plate 84 made of a conductive material such as aluminum.
It is provided above. Then, the plate 84 is attached on the holder 83, and the urethane sheet 82 is attached on the plate 84.

The end of the plate 84 and the end of the above-mentioned charge trapping electrode 90 are screwed with screws 85, and the charge trapping electrode 90, the plate 84 as a voltage applying member and the brush The sheet of the member 86 is electrically conductive. As described above, since the charge trapping electrode 90 is directly charged and receives the ions discharged from the corona wire 31, the charged charge trapping electrode 9 is charged.
The plate 84 and the sheet of the brush-like member 86 which are electrically connected to the zero are also charged. That is, a voltage can be applied to the sheet of the brush-like member 86 without providing a dedicated power supply for the brush-like member 86.

In this embodiment, as shown in FIG. 2, a grid cover 100 is provided as a partition member above the paper dust removing device 80. The grid cover 100 is made of, for example, an insulating resinous material such as PET, and as shown in FIG.
2 covers the non-woven fabric 81 at both end positions.
As shown in FIG. 3, the size is formed to cover a part of the grid electrode 33 of the charger 30. However, grid cover 10
The position of the end of the zero grid electrode 33 is adjusted so as not to cover the corona wire 31. Therefore, the charging operation of the photosensitive drum 20 by the charger 30 is not adversely affected.

The grid cover 100 is shown in FIGS.
As shown in (D), it is attached on the urethane sheet 82 to which the nonwoven fabric 81 is attached, using an adhesive or a double-sided tape. 4A is a perspective view showing the grid cover 100 and the paper dust removing device 80, and FIG.
(A) is an enlarged view of a portion C surrounded by a circle, (C) is a side view of the grid cover 100 and the paper dust removing device 80 viewed from the direction of arrow A shown in (A), and (D) is a grid cover. FIG. 2 is an enlarged plan view showing a mounting portion of the apparatus.

The grid cover 100 is shown in FIGS.
As shown in FIG. 2C, it is bent at a predetermined angle with respect to the attachment portion, and is configured to be in press contact with the grid electrode 33 as shown in FIG. Further, even when the paper dust removing device 80 is mounted on the process cartridge 2a, a predetermined gap is set between the grid cover 100 and the nonwoven fabric 81. Therefore, the contact state of the nonwoven fabric 81 with the photosensitive drum 20 is not adversely affected.

As shown in FIG. 3, the grid covers 100 are provided at positions corresponding to both ends of the photosensitive drum 20 outside the image forming area. As shown in FIG. 3, both ends of the developing roller 57 outside the image forming area are in press contact with seal members 112 at both ends, and toner leakage occurs from a contact boundary portion of the seal members 112 at both ends. As shown by the dotted line in FIG. 3, the toner adheres linearly. Then, the toner is transferred to both end portions of the photosensitive drum 20 outside the image forming area because sufficient or normal triboelectric charge is not provided. Then, it accumulates at the contact portion between the nonwoven fabric 81 and the photosensitive drum 20, or passes through the contact portion. When the amount of accumulated toner increases or passes through the contact portion, the toner scatters outward from the contact portion.

However, in the present embodiment, the contact portion where the above-described leakage toner accumulates is covered by the grid cover 100, and a part of the grid electrode 33 is also covered by the grid cover 100 as described above. Covered.

Therefore, even when the toner scatters, the scattered toner does not enter the inside of the charger 33 or adhere to the wire 31. As a result, in the charger 30, abnormal discharge due to toner does not occur, and printing failure or noise can be reliably prevented.

(Example of Operation) In the laser beam printer 1 of the present embodiment as described above, the surface of the photosensitive drum 20 is uniformly charged by the charger 30 and the laser beam modulated according to the image information from the laser scanner unit 40. When L is irradiated, an electrostatic latent image is formed on the surface of the photosensitive drum 20. This electrostatic latent image is visualized with toner by the developing device 50, and the visible image formed on the photosensitive drum 20 is transported by the photosensitive drum 20 to a transfer position.
At the transfer position, the paper is supplied via the paper feed roller 11 and the registration rollers 12 and 13, and the visible image is transferred to the paper by a transfer bias applied by the transfer roller 21.

Next, the sheet is conveyed to the fixing unit 70, and is nipped and conveyed by the heating roller 71 and the pressing roller 72 of the fixing unit 70. The visible image on the sheet is pressed and heated to be fixed on the sheet. You. Then, the sheet is discharged to the discharge tray 75 above the laser beam printer 1 by the pair of transport rollers 73 and the discharge rollers 74, and the image forming operation is completed.

On the other hand, the toner remaining on the photosensitive drum 20 after the transfer is collected by the developing device 50 and is again subjected to development. As described above, the laser beam printer 1 of the present embodiment
Employs a so-called cleaner-less development method.
Therefore, since a waste toner storage container for scraping and storing the toner remaining on the photosensitive drum 20 is not required, the size of the apparatus can be reduced, and the toner can be effectively used.

Paper dust adheres to the photosensitive drum 20 after the transfer. Of the paper dust, large fibrous paper dust is caught by the brush-like member 86, and small paper dust is removed by the nonwoven fabric 81. Removed. Particularly, in the present embodiment, the brush-like member 86 is charged by the charge trapping electrode 90 charged by the discharge from the corona wire 31 of the charger 30.
Since a voltage is applied to, an extremely high paper dust removing ability is exhibited. The paper dust is charged to a polarity opposite to that of the toner by a bias applied to the toner during transfer and having a polarity opposite to that of the toner. On the other hand, in the present embodiment, since the reversal development method is employed, the polarity of the voltage applied to the charger 30 is the same as the charge polarity of the toner. Therefore,
The polarity of the charge trapping electrode 90 charged by the discharge from the corona wire 31 and the polarity of the brush-like member 86 conducting to the charge trapping electrode 90 are also the same as the charge polarity of the toner, and the paper powder can be collected well. .

As described above, the image forming apparatus according to the present embodiment can apply an appropriate voltage to the brush-like member 86 without providing a dedicated power supply for the brush-like member 86, so that the cost is reduced. Can be significantly reduced.

Even if the toner leaks from the developing device 50 as described above and is transferred to the photosensitive drum 20 and comes into contact with the nonwoven fabric 81, the grid cover 100 as described above is provided in the present embodiment. Therefore, it is possible to reliably prevent the toner scattered from the contact portion between the nonwoven fabric 81 and the photosensitive drum 20 from entering the inside of the charger 30. As a result, abnormal discharge does not occur, printing defects are prevented, and various errors due to noise can be reliably prevented.

The corona discharge electrode of the charger is as follows:
Needle-shaped electrodes, as well as wire electrodes as described above,
Alternatively, a saw-like electrode may be used.

Further, in the above-described embodiment, an example was described in which the photosensitive member was used as the voltage-applying member. However, the present invention is not limited to this. For example, an intermediate transfer member in a color image forming apparatus, The present invention is applicable even when paper or the like is used as the voltage applied member.

Further, in the present embodiment, an example in which a PET sheet is used as an example of the partition member has been described. However, the present invention is not limited to such a configuration. It may be a member formed of resin.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. Can easily be inferred.

[0058]

According to the image forming apparatus of the first aspect,
The developer leaked from both ends in the longitudinal direction of the developing device is transferred to both end positions outside the image forming area in the longitudinal direction of the electrostatic latent image carrier, and the paper dust disposed opposite to the electrostatic latent image carrier is transferred. Even if the paper dust removing means may come into contact with the paper dust removing means, a partition member is provided between the charger and the paper dust removing means at the both end positions. It is possible to reliably prevent the developer scattered from from entering the inside of the charger. As a result, abnormal discharge in the charger can be reliably prevented, and printing errors due to abnormal discharge or various errors due to noise can be reliably prevented.

According to the image forming apparatus of the present invention, since the partition member is provided so as to protrude to a position covering a part of the charging device facing the electrostatic latent image carrier, the partition member is provided. The scattering developer can be reliably prevented from entering the inside of the charger without adversely affecting the charging operation of the electrostatic latent image carrier by the charger. As a result, abnormal discharge in the charger can be reliably prevented, and printing errors due to abnormal discharge or various errors due to noise can be reliably prevented.

According to the image forming apparatus of the third aspect, since the partition member is formed of an insulating resinous member,
Even when it comes into contact with a part of the charger, no discharge or the like is generated and the molding is easy, so that the shape can be processed so as not to adversely affect the paper dust removing action of the paper dust removing means, for example.

According to the process cartridge of the fourth aspect, the developer leaked from both ends in the longitudinal direction of the developing device is transferred to both end positions outside the image forming area in the longitudinal direction of the electrostatic latent image carrier. Even if it may come in contact with paper dust removing means arranged opposite to the electrostatic latent image carrier, a partition member is provided between the charger and the paper dust removing means at the both end positions. Therefore, it is possible to reliably prevent the developer scattered from the contact portion with the paper dust removing unit from entering the inside of the charger. As a result, abnormal discharge in the charger can be reliably prevented, and printing errors due to abnormal discharge or various errors due to noise can be reliably prevented.

According to the process cartridge of the fifth aspect, since the partition member is provided so as to protrude to a position covering a part of the charging device facing the electrostatic latent image carrier, the partitioning member is provided. Thus, it is possible to reliably prevent the scattered developer from entering the inside of the charger without adversely affecting the charging action on the electrostatic latent image carrier due to the above. As a result, abnormal discharge in the charger can be reliably prevented, and printing errors due to abnormal discharge or various errors due to noise can be reliably prevented.

According to the process cartridge of the present invention, since the partition member is formed of an insulating resinous material, even if it comes into contact with a part of the charger, no discharge or the like is generated. Since the molding is easy, for example, the shape can be processed so as not to adversely affect the paper dust removing action of the paper dust removing means.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a process cartridge in the image forming apparatus of FIG.

FIG. 3 is a plan view showing the vicinity of a paper dust removing unit and a partition member in the process cartridge of FIG. 1;

4A is a perspective view showing a partition member and a paper dust removing means of FIG. 3, FIG. 4B is an enlarged view of a portion C surrounded by a circle in FIG. 4A, and FIG. FIG. 4D is a side view of the partition member and the paper dust removing unit viewed from the direction of arrow A shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser beam printer 20 Photosensitive drum 30 Charger 31 Corona discharge wire 32 Shield 33 Grid electrode 80 Paper dust removing device 81 Nonwoven fabric 82 Urethane sheet 84 Plate 100 Grid cover

Claims (6)

[Claims] A charging device having a corona discharge electrode, an electrostatic latent image carrier charged to a predetermined potential by the charging device, and a paper dust removing unit disposed opposite to the electrostatic latent image carrier. An image forming apparatus comprising: a partition member at both end positions outside an image forming area in a longitudinal direction of the electrostatic latent image carrier and between the charger and the paper dust removing unit. An image forming apparatus, characterized in that: 2. The image forming apparatus according to claim 2, wherein the partition member is provided so as to protrude to a position covering a part of the charger facing the electrostatic latent image carrier. apparatus. 3. The image forming apparatus according to claim 1, wherein the partition member is formed of an insulating resinous member. 4. A charging device having a corona discharge electrode, an electrostatic latent image carrier charged to a predetermined potential by the charging device, and a paper dust removing unit disposed opposite to the electrostatic latent image carrier. A process cartridge provided with a partition member between the charger and the paper dust removing unit at both end positions outside the image forming area in the longitudinal direction of the electrostatic latent image carrier. A process cartridge characterized by the above-mentioned. 5. The process cartridge according to claim 4, wherein the partition member is provided so as to protrude to a position covering a part of a portion of the charger facing the electrostatic latent image carrier. . 6. The process cartridge according to claim 4, wherein the partition member is formed of an insulating resinous member.