JPH0844259A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate ozone gas generated in the electrostatic charger of a process unit in a cleanerless image forming device using the process unit. CONSTITUTION:The upper part of the electrostatic charger 3 of the process unit 1 is provided with an aperture part 3a along the spreading direction of an electric discharge wire 5. A sheet member 6 whose size in the spreading direction of the wire 5 is shorter than the size of the aperture part 3a is fitted to the charger 3 so as to form a gap D in the spreading direction of the wire 5. When a heat radiation fan F is rotated at the using time of the image forming device, the ozone gas in the charger 3 is passed through the gap D and discharged to the outside of the charger 3 by the flow of air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus using a discharging means.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, when a surface of a photoconductor is charged by a corona discharge type charger, ozone gas is generated by corona discharge of the charger. This ozone gas has a strong oxidizing action. or,
Since this ozone gas is heavier than air, there is a problem that when the charger is located above the photoconductor, the ozone gas falls on the photoconductor and deteriorates the photoconductor.

FIG. 4 is a cross-sectional view of an essential part showing a structure in the vicinity of a photoconductor of a conventional electrophotographic cleanerless image forming apparatus. Around the photoconductor 40, a charger 41 for applying a predetermined uniform electric potential to the photoconductor 40 along the rotation direction of the photoconductor 40, and for exposing the photoconductor 40 to form an electrostatic latent image And an developing device 43 for supplying toner to the electrostatic latent image to develop the electrostatic latent image.

Further, for the developing unit 43, the photosensitive member 4
An image forming unit including a transfer unit 45, a static eliminator 46, and a memory removing member 47 is provided on the downstream side in the rotational direction of 0. The transfer device 45 is for transferring the developed toner image onto the recording paper, and the static eliminator 46 is for exposing the surface of the photoconductor 40 after completion of the transfer to remove the charge.

The memory removing member 47 is the photosensitive member 4 after the charge is removed.
This is for disturbing the toner remaining on the surface 0 so that the residual toner does not affect the next image forming process. After the transfer is completed, the recording paper is heated by the fixing unit 48.
Sent to The heat fixing device 48 includes a heating roller 48a.
And a pressure roller 48b.

A rod-shaped halogen lamp 49 is inserted into the heating roller 48a of the heat fixing device 48 as a heat source. Therefore, while the halogen lamp 49 is energized,
The heating and fixing device 48 becomes hot and heats the air around it. Since the heating of the air adversely affects each part of the cleanerless image forming apparatus, the cleanerless image forming apparatus is provided with the heat radiation fan F. By the heat radiation fan F, the heated air inside the image forming apparatus is
It is released to the outside of the device.

In the charger 41, a storage case 41b for the discharge wire 41a is formed integrally with the case of the process unit. In order to release the ozone gas as described above, an opening 44 is provided in the upper portion of the charger 41. In the image forming process, when the photoconductor 40 is charged, the air inside the image forming apparatus flows by the rotation of the heat radiation fan F so as to suck out the ozone gas inside the charger 41. Therefore, the ozone gas generated by the discharge of the discharge wire 41a is discharged from the opening 44 to the charger 41.
It is designed to be discharged to the outside.

As described above, the opening 4 is provided on the charger 41.
By providing 4, the cleaning member 46 can be inserted into the charger 41 from the opening 44. Therefore, when the image forming apparatus is used, the opening 4
It becomes easy for the cleaning member 46 to remove foreign matter such as dust that has entered from 4 and adhered to the inner wall of the discharge wire 41a or the storage case 41b.

[0009]

The toner supplied from the developing device 43 adheres to the photoconductor 40 due to the potential difference between the potential of the photoconductor 40 and the potential of the toner itself. However, in the cleanerless image forming apparatus, the residual toner on the photoconductor 40 after the transfer has the same potential as the photoconductor 40 when being disturbed by the memory removing member 47, and the adhesive force to the photoconductor 40 decreases.

Therefore, when the ozone gas in the charger 41 is sucked out of the charger 41 from the opening 44 by the rotation of the heat radiation fan F as described above, the residual toner on the photoconductor 40 is sucked up. If the residual toner sucked up at this time adheres to the discharge wire 40a of the charger 41, defective charging of the photoconductor 40 occurs, which adversely affects the image forming process. As a result, the image formed on the recording paper may be a defective image.

Further, when the process unit is loaded in the image forming apparatus, the toner in the developing device 43 is scattered into the image forming apparatus. As described above, the opening 4 is formed in the charger 41.
4 is provided, the scattered toner is discharged from the opening 44.
Into the charger 41 from above, and the discharge wire 41
There is also a problem that it is easily attached to a.

FIG. 5 is a cross-sectional view of the main part in the vicinity of the photoconductor of the image forming apparatus in consideration of the absorption of the residual toner and the invasion of the scattered toner as described above. The opening portion 44 of the charger 41 is provided with sheet members 45 on the left and right so that the slit S is provided at the center. This sheet member 4
The air flow due to the rotation of the heat radiation fan F is blocked by 5. Therefore, it is possible to prevent the residual toner on the photoconductor 40 from being sucked up and attached to the discharge wire 41a in the charger 41.

Further, by making the sheet member 45 flexible, when the cleaning member 46 is inserted through the slit S, the portions where the cleaning member 46 is inserted are provided on the left and right sides of the opening 44. The sheet member 45 bends inward. Therefore, the cleaning member 46 can remove the foreign matter adhering to the discharge wire 41a.

When the cleaning member 46 is removed after the cleaning is completed, the sheet member 45 returns to its original position by its elasticity. Then, the sheet member that has returned to the original position prevents foreign matter such as scattered toner in the image forming apparatus from entering the charger 41 from above.

However, if the opening portion 44 is shielded by the sheet member 45 as described above, the sheet member 4 is removed.
5 is an obstacle to sucking out ozone gas generated from the discharge wire 41a when the photoconductor 40 is charged. Therefore, there remains a problem that the photoconductor 40 is deteriorated by the oxidizing action of the ozone gas.

[0015]

In order to solve the above problems, the invention of claim 1 provides an electrophotographic image forming apparatus having a discharging means, wherein the discharging means is provided behind the discharging member. The discharge member is opened along the longitudinal direction, and an openable and closable cover body and an ozone suction hole are provided in the opening.

According to a second aspect of the invention, the cover body is
It is a flexible sheet member, and is characterized in that at least one end portion in the width direction thereof is fixed at the rear end of the discharge means along the longitudinal direction thereof.

According to a third aspect of the present invention, the ozone suction hole is a long hole provided along the longitudinal direction of the discharge member, and the long hole is the center of the discharge means in the width direction. It is characterized in that it is provided at a position shifted to one end side more.

Further, in the invention of claim 4, the ozone suction hole is a long hole extending in the longitudinal direction of the opening of the discharge means.
It is characterized in that it is constituted by at least one long hole continuous with the long hole and extending in the width direction of the opening.

[0019]

As described above, according to the first aspect of the present invention, by providing the cover body which can be opened and closed with respect to the opening portion and the ozone suction hole portion, when the image processing apparatus is used, An air flow is generated to the extent that only the ozone gas in the discharge means is sucked. Therefore, the ozone gas can be discharged from the discharge means without sucking up the residual toner on the photoconductor.

According to the invention of claim 2, the cover body is a flexible sheet member, and one end of the cover body is fixed to the rear end of the discharge means along the longitudinal direction of the discharge means. As a result, in the normal case, the cover body is closed to the opening with its own waist. Further, when a cleaner member for cleaning the discharge member is inserted, only the cover body of the portion where the cleaner member is inserted is bent to be in an open state. Therefore, the cover body having a simple structure can freely open and close the opening.

Further, according to the invention of claim 3, the position of the long hole for sucking ozone is shifted to one side end side with respect to the center of the discharge means in the width direction. During use, foreign matter such as scattered toner that passes through the elongated holes from outside the discharge means and enters the discharge means is prevented from adhering to the discharge member.

Further, according to the invention of claim 4, the ozone suction long hole is provided with a long hole along the longitudinal direction of the opening of the discharge means, and is continuous with the long hole and along the width direction of the opening. Since the cover member is easily bent at the time of cleaning the discharge member, the cleaner member inserted into the opening is slid to both edges of the opening in the discharge member stretching direction. Can move. Therefore, the discharge member is reliably cleaned up to the end by the cleaner member.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG.
FIG. 4 is a top view of the vicinity of a charger which is a discharging unit of a process unit of an electrophotographic image forming apparatus. And
FIG. 2 is a sectional view taken along line AA of FIG. The casing of the process unit 1 rotatably supports the photosensitive drum 2 on its shaft portion 2a. The photosensitive drum 2 is rotating clockwise in FIG. The charger 3 and the exposure device 4 are located above the photosensitive drum 2. The charger 3 is for charging the photosensitive drum 2 to a predetermined potential,
The exposure device 4 irradiates the photosensitive drum 2 with light to form an electrostatic latent image on the photosensitive drum 2.

Although not shown, toner is supplied to the periphery of the photosensitive drum 2 from the exposure unit 4 along the downstream side of the clockwise rotation of the photosensitive drum 2 in FIG. A developing device for developing the electrostatic latent image and a transfer device for transferring the developed toner onto the recording paper are provided. Further, on the downstream side in the rotation direction of the photosensitive drum 2 from the transfer device, a static eliminator for exposing and discharging the surface of the photosensitive drum 2 after transfer, and residual toner remaining on the photosensitive drum 2 after transfer are provided. And a memory removing member for removing the memory.

The charger 3 is provided with a discharge wire 5 as a discharge member in the axial direction of the photosensitive drum 2.
This discharge wire 5 is between the support members 7 and 8,
It is supported with a proper tension applied. or,
The charger 3 is arranged along the extending direction of the discharge wire 5,
An opening 3a is provided above the discharge wire 5. Further, a sheet member 6 is provided in the opening 3a. The sheet member 6 has a light-shielding property in order to prevent deterioration of the photosensitive drum 2 due to external light that irradiates the photosensitive drum 2 through the opening 3a.

The sheet member 6 is flexible, and the dimension C of the sheet member 6 in the longitudinal direction of the opening 3a is
It is shorter than the dimension B of the opening 3a. The sheet member 6 is attached to the charger 4 so that a space D is formed between the edge of the opening 3a and the edge of the sheet member 6 in the width direction of the opening 3a. At this time, the dimension of the interval D is about 0.5 mm to 2.0 mm. As a result, the opening 3a of the charger 3 is provided with a long hole 3b for sucking ozone gas.

When the image forming apparatus is used, heat is generated by the operation of each device in the image forming apparatus. In order to prevent the temperature inside the image forming apparatus from rising due to the generation of heat, the image forming apparatus is provided with a heat dissipation fan F.
The heat radiating fan F is rotationally driven by a drive source (not shown), and the rotation of the heat radiating fan F discharges the air whose temperature inside the image forming apparatus has risen outside the image forming apparatus.

When the photosensitive drum 2 is charged with a predetermined potential, a high voltage is applied to the discharge wire 5 from a high voltage transformer (not shown) of the image forming apparatus main body. When a high voltage is applied, the discharge wire 5 causes corona discharge, and the photosensitive drum 2 is charged to a predetermined potential. At this time, the discharge wire 5 generates ozone gas. When the air flow generated by the heat radiation fan F occurs, the elongated hole 3b serves as a duct for sucking ozone gas. Therefore, the ozone gas passes through the long hole 3b and is discharged from the inside of the charger 3 to the outside.

When the process unit 1 is loaded in the main body of the image forming apparatus, toner is scattered from the developing device (not shown) into the image forming apparatus. At this time, the scattered toner may enter the charger 3 through the long hole 3b. However, with respect to the position of the discharge wire 5 stretched along the longitudinal direction of the opening 3a, the long hole 3
b is provided at a position displaced to one side edge side in the longitudinal direction of the opening 3a. Therefore, even if the scattered toner enters the charging unit 3, the scattered toner is prevented from adhering to the discharge wire 5.

FIG. 3 shows the state of cleaning the discharge wire,
FIG. 4 is a cross-sectional view of the vicinity of the charger of the process unit. The cleaning member 9 is provided at its tip with a cleaning surface 9a such as a felt brush that is sufficiently elastically deformed when coming into contact with the discharge wire 5 and does not damage the discharge wire 5. Since the sheet member 6 is attached to the housing of the process unit 1 in the above-described state, the opening 3a is formed.
It can be opened and closed freely.

When the cleaning member 9 is inserted through the opening 3a, the sheet member 6 bends so as to come into contact with the inner wall of the charger 3. Then, the discharge wire 5 is cleaned by the cleaning surface 9a of the cleaning member 9. Further, due to the action of the long hole 3b having the above-mentioned structure, the sheet member 6 is easily bent at both ends of the opening 3a. Therefore, the cleaning member 9 can slide to the end of the opening 3a, and the end of the discharge wire 5 can be easily cleaned.

After cleaning, when the cleaning member 9 is pulled out from the opening 3a, the sheet member 6 returns to its original position due to the waist of the sheet member 6 itself.

The sheet member 6 is not limited to the shape as in this embodiment, but instead of the distance D, a long hole extending in the longitudinal direction of the opening 3a is formed in the body of the sheet member 6.
A long hole that is continuous with the long hole and extends in the width direction of the opening 3a may be provided. In this case, it is desirable that the position of the long hole along the longitudinal direction of the opening 3a is shifted to one side edge side with respect to the position of the discharge wire 5 stretched in the longitudinal direction of the opening 3a.

[0034]

As described above, according to the present invention, the cover body having a simple structure can freely open and close the opening provided in the charger. Therefore, it becomes easy to clean the discharge member with the cleaning member. Further, when the image processing apparatus is used, the long hole provided along the longitudinal direction of the opening can suck the ozone gas in the charger without sucking up the residual toner, so that the deterioration of the photoreceptor due to the ozone gas can be prevented. Therefore, it is possible to prevent image defects due to deterioration of the photoconductor.

Further, the long hole provided along the longitudinal direction of the opening as described above is displaced to one side edge portion with respect to the position of the discharge member stretched along the longitudinal direction of the opening. Since the toner is scattered at the time of loading the process unit, it does not adhere to the discharge member when entering the charger. As a result, the discharge member can be prevented from being contaminated, and the deterioration of image quality due to the contamination of the discharge member can be prevented.

[Brief description of drawings]

FIG. 1 is a top view of the vicinity of a charger of a process unit of a cleanerless image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of the vicinity of the charger of the process unit of the cleanerless image forming apparatus according to the embodiment of the present invention when the cleaning member is inserted.

FIG. 4 is a sectional view of a process unit of a conventional cleanerless image forming apparatus.

FIG. 5 is a cross-sectional view of a process unit of a conventional cleanerless image forming apparatus in which a sheet member is provided in an opening of a charger.

[Explanation of symbols]

 1 Process Unit 2 Photosensitive Drum 3 Charging Device 4 Exposure Device 5 Discharge Wire 6 Sheet Member 9 Cleaning Member F Heat Dissipation Fan

Claims (4)

[Claims] 1. An electrophotographic image forming apparatus provided with a discharging means, wherein the discharging means has an opening behind the discharging member along the longitudinal direction of the discharging member. An image forming apparatus, wherein an openable and closable cover body and an ozone suction hole are provided in the opening. 2. The cover body is a flexible sheet member, and at least one end portion in the width direction thereof is fixed to a side portion along the longitudinal direction of the opening portion. 1. The image forming apparatus according to 1. 3. The ozone suction hole is an elongated hole provided along the longitudinal direction of the discharge member, and the elongated hole is
The image forming apparatus according to claim 1 or 2, wherein the image forming apparatus is provided at a position shifted to one end side from a center of the discharge means in the width direction. 4. The ozone suction hole comprises a long hole extending in the longitudinal direction of the opening of the discharge means, and at least one long hole continuous with the long hole and extending in the width direction of the opening. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured.