JP2003287941A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of preventing image deterioration that is caused by ozone generated by a corona discharge electrifier. <P>SOLUTION: The corona discharge electrifier is provided with an air fan 71 that blows air through a duct. At least part of the duct or the air fan 71 is disposed near to drive motors 26, 44, and 63 and a control board 12, which are heat sources of the image forming apparatus. Thus, blown air is heated and ozone in the vicinity of the corona electrifier is removed by means of the heated air and also ozone decomposition is accelerated to reduce ozone generation. <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 an image forming apparatus such as a printer, a facsimile or a copying machine, which forms an image by using an electrophotographic technique. In particular, it relates to measures against ozone in an apparatus using a corona discharge charger.

2. Description of the Related Art Generally, an image forming apparatus using electrophotography has a photosensitive member (image carrier) having a photosensitive layer on its outer peripheral surface.
A charging means for uniformly charging the outer peripheral surface of the photoconductor, and an exposing means for selectively exposing the outer peripheral surface uniformly charged by the charging means to form an electrostatic latent image. A developing unit that applies toner, which is a developer, to the electrostatic latent image formed by the exposing unit to form a visible image (toner image); and a toner image developed by the developing unit such as a sheet to be transferred. And a transfer means for transferring to a recording material.
A device using a corona discharge charger is known as one of the charging means.

[0002]

When a corona discharge charger is used as the charging means, ozone is generated in the vicinity of the charger, and if this ozone accumulates, it adversely affects the surface of the photoconductor and deteriorates the image. There's a problem.

An object of the present invention is to provide an image forming apparatus which can solve the above problems and prevent image deterioration due to ozone.

[0004]

In order to achieve the above object, the image forming apparatus according to claim 1 is provided with a blower fan for blowing air through a duct to the corona discharge charger.
At least a part of the duct or the blower fan is arranged close to the heat source in the image forming apparatus. An image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, wherein the blower fan is a paper transport system drive motor, a fixing device drive motor, an image carrier drive motor, and an intermediate transfer body drive in the image forming apparatus. It is characterized in that it is arranged close to at least one of the motor, the developing device drive motor, the heat fixing roller, and the control substrate.

[0005]

According to the image forming apparatus of the present invention, the corona discharge charger is provided with a blower fan for blowing air through the duct, and at least a part of the duct or the blower fan is arranged close to the heat source in the image forming apparatus. Therefore, according to the image forming apparatus of the first aspect, the following operational effects can be obtained. That is, since air is blown from the blowing fan through the duct to the corona discharge charger, ozone is prevented from accumulating near the charger, and therefore ozone is prevented from adversely affecting the surface of the photoconductor and images are not deteriorated. Moreover, since at least a part of the duct or the blower fan is arranged close to the heat source in the image forming apparatus, the blown air is heated by the heat source, and the heated air is fed to the corona charger. Therefore, the decomposition of ozone is promoted, and the generation of ozone itself is reduced. Therefore, according to this image forming apparatus, it is possible to reliably prevent image deterioration due to ozone. According to the image forming apparatus of claim 2,
In the image forming apparatus described above, the blower fan includes a paper conveyance system driving motor, a fixing device driving motor, an image carrier driving motor, an intermediate transfer member driving motor, a developing device driving motor, a heat fixing roller, and a control in the image forming apparatus. Since it is arranged close to at least one of the substrates for air supply, the blower fan or its periphery is the above-mentioned paper transport system drive motor, fixing device drive motor, image carrier drive motor, intermediate transfer body drive motor, and developing device. It is heated by the heat generated from at least one of the drive motor, the heat fixing roller, and the control board. Therefore, the air fed to the corona discharge charger can be heated without providing a separate heat source.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic front view showing the internal structure of an embodiment of a color image forming apparatus according to the present invention. The image forming apparatus is an apparatus capable of forming a full-color image on both sides of a sheet, and the case 10
An image carrier unit 20 housed in the case 10, an exposure unit 30 as an exposure unit, a developing device 40 as a developing unit, and an intermediate transfer unit 50.
And a fixing unit 60 as fixing means.

The case 10 has a frame 11 of the main body of the apparatus.
(Only the frame on the back side is shown in FIG. 2) is provided, and each unit and the like are attached to the frame 11.

The image carrier unit 20 includes a photoconductor (image carrier) 21 having a photosensitive layer on its outer peripheral surface, and a corona discharge charger 22 as a charging means for uniformly charging the outer peripheral surface of the photoconductor 21. And the outer peripheral surface of the photoconductor 21 uniformly charged by the charger 22 is exposed to the exposure unit 3
A laser beam L from 0 is selectively exposed to form an electrostatic latent image, and a toner as a developer is applied to the electrostatic latent image by the developing device 40 to form a visible image (toner image). The toner image is primarily transferred to the intermediate transfer member (intermediate transfer belt) 51 of the intermediate transfer member unit 50 at the primary transfer portion T1 and further secondary transferred to the sheet to be transferred at the secondary transfer portion T2. ing.

As shown in FIG. 1, in the case 10, a sheet having an image formed on one side by the secondary transfer section T2 is conveyed toward a sheet discharging section (sheet discharging tray section) 15 on the upper surface of the case 10. And a return path 17 for switching back the sheet conveyed toward the sheet discharge section 15 by the conveyance path 16 and returning it toward the secondary transfer section T2 so as to form an image on the other surface. And are provided. Case 1
A paper feed tray 18 for stacking and holding a plurality of paper sheets and a paper feed roller 19 for feeding the paper sheets one by one toward the secondary transfer portion T2 are provided in the lower part of 0.

The developing device 40 is a rotary developing device,
A plurality of developing device cartridges are detachably attached to the rotating body 41. In this embodiment, a yellow developing device cartridge 42Y, a magenta developing device cartridge 42M, a cyan developing device cartridge 42C, and a black developing device cartridge 42K.
Is provided (only the developing device cartridge 42Y for yellow is directly drawn in the figure), and the rotator main body 41
Rotates in the direction of the arrow at a pitch of 90 degrees, so that the developing roller 43 is selectively brought into contact with the photoconductor 21.
The surface of the photoconductor 21 can be selectively developed.

The exposure unit 30 is adapted to irradiate the photoconductor 21 with the laser beam L through an exposure window 31 made of plate glass or the like.

The intermediate transfer body unit 50 includes a unit frame (not shown), a driving roller 54, a driven roller 55, and a primary transfer roller 5 which are rotatably supported by the frame.
6, a guide roller 57 for stabilizing the state of the belt 51 at the primary transfer portion T1, and a tension roller 58
And the intermediate transfer belt 51 wound around these rollers and stretched, and the belt 51 is circularly driven in the direction of the arrow in the figure. Photoconductor 21 and primary transfer roller 56
The primary transfer portion T1 is formed between
The drive roller 54 and the secondary transfer roller 1 provided on the main body side
The secondary transfer portion T2 is formed at the pressure contact portion with 0b. The secondary transfer roller 10b can be brought into and out of contact with the drive roller 54 (and thus with respect to the intermediate transfer belt 51), and when it comes into contact with the drive roller 54, the secondary transfer portion T2 is formed.
Therefore, when forming a color image, toner images of a plurality of colors are superposed on the intermediate transfer belt 51 in a state where the secondary transfer roller 10b is separated from the intermediate transfer belt 51, and then a color image is formed. The secondary transfer roller 10b comes into contact with the intermediate transfer belt 51 and the paper is supplied to the abutting portion (secondary transfer portion T2), whereby the toner image is transferred onto the paper. The sheet on which the toner image is transferred passes through the heating roller pair 61 of the fixing unit 60 so that the toner image is fixed, and the sheet is ejected toward the sheet ejection tray section 15.

FIG. 2 is a rear view of the image forming apparatus with the case 10 removed, FIG. 3 is a perspective view showing the image carrier unit 20 and the blower unit 70 removed from the apparatus main body, and FIG. 4 is an exploded perspective view of the blower unit. It is a figure.

As shown in FIG. 4, the blower unit 70 is
The fan 71, the duct 72, and the duct cover 73 are provided. The blower unit 70 is configured by incorporating a blower fan 71 into an intake port 72a of a duct 72 and connecting a duct cover 73 to the duct 72 from the outside. The duct 72 has the intake port 72a, an air passage 72b communicating with the intake port 72a, and a blower port 72c communicating with the air passage 72b. On the other hand, the duct cover 73
Is a back cover portion 73a having a large number of holes 73d and covering the rear surface side of the blower fan 71, a lower surface cover portion 73b covering the lower surface side of the blower fan 71, and an air passageway covering the air passageway 72b portion of the duct 72. It is a sheet metal member integrally formed with the forming portion 73c. Therefore, the blower fan 71 is connected to the duct 72.
The intake port 72a and the air passage 72b are formed by incorporating the duct cover 73 into the duct 72 from the outside thereof.

As shown in FIG. 3, the blower unit 70 is connected to the image carrier unit 20 by fitting the blower port 72c into the connection port 24 formed in the case 23 of the image carrier unit 20. To be done. The connection port 24 is open toward the charger 22 in the longitudinal direction of the charger 22. Therefore, when the blower fan 71 operates,
Air from the blower fan 71 is blown from the longitudinal direction of the charger 22 through the duct 72 and the connection port 24.

The image carrier unit 20 and the blower unit 70 as described above are provided with the engaging portion 2 of the image carrier unit 20.
5 are engaged with the frame 11 of the apparatus main body, and the engaging portions 74 and 75 of the blower unit 70 are engaged with the frame 11, so that they are detachably attached to the apparatus main body. In the mounted state, as shown in FIG. 2, the blower fan 71, the back cover portion 73a of the duct cover 73 which is a sheet metal member, the bottom cover portion 73b, and the intake port 72a of the duct 72 serve as a heat source (heating component). It is surrounded by a drive motor 63 of a certain paper transport system and fixing unit 60, a drive motor 26 of the photoconductor 21 and the intermediate transfer belt 51, a drive motor 44 of the developing device, and a control substrate 12 of the image forming apparatus. It is arranged close to each of these motors and the like. Further, the air duct forming portion 73 of the duct cover 73
c is brought into close contact with a frame (for example, the frame 11) to which the motor or the like which is the heat generating member is attached. If the blower fan 71 and / or the duct 72 can be arranged close to the fixing roller 61, it is desirable to do so.

According to the image forming apparatus as described above, the following operational effects can be obtained. (A) Since the blower fan 71 for blowing air through the duct 72 is provided in the corona discharge charger 22, and at least a part of the duct 72 or the blower fan 71 is arranged close to the heat source in the image forming apparatus. Various operational effects can be obtained. That is, since air is blown from the blower fan 71 to the corona discharge charger 22 through the duct 72, ozone is prevented from staying near the charger 22, and therefore the adverse effect of ozone on the surface of the photoconductor 21 is also prevented. It will not deteriorate. Moreover, the duct 7
2 or at least part of the blower fan 71 is arranged close to the heat source in the image forming apparatus, so that the blown air is heated by the heat source, and the heated air is fed to the corona charger 22. Therefore, the decomposition of ozone is promoted, and the generation of ozone itself is reduced. Therefore, according to this image forming apparatus, it is possible to reliably prevent image deterioration due to ozone. (B) The blower fan 71 is used for the paper conveyance system drive motor 63, the fixing device drive motor 63, the image carrier drive motor 26, the intermediate transfer body drive motor 26, the developing device drive motor 44, the heat fixing roller 61, in the image forming apparatus. And control board 1
By arranging in close proximity to at least one of the two, the blower fan 71 or its periphery is the above-mentioned paper transport system drive motor, fixing device drive motor, image carrier drive motor, intermediate transfer body drive motor, and developing device drive. The heat is generated by the heat generated from at least one of the motor, the heat fixing roller, and the control board. Therefore, the air fed to the corona discharge charger 22 can be heated without separately providing a heat source.

(C) In this embodiment, as described above, the blower fan 71 and the duct cover 73 which is a sheet metal member.
The rear cover portion 73a, the lower surface cover portion 73b, and the intake port 72a of the duct 72 are heat sources (heat-generating components) of the paper transport system, the drive motor 63 of the fixing unit 60, and the photoconductor 2.
1 and the drive motor 26 of the intermediate transfer belt 51, the drive motor 44 of the developing device, and the control substrate 12 of the image forming apparatus, and are arranged close to these motors and the like. The fan 71 and the duct 72 or their periphery are efficiently heated by the heat generated by the motor and the like. Therefore, without separately providing a heat source, the corona discharge charger 22
It is possible to efficiently reduce the generation of ozone.

(D) Further, the air passage forming portion 73c of the duct cover 73, which is a sheet metal member having excellent thermal conductivity, is brought into close contact with the frame (for example, the frame 11) to which the motor, which is the heat generating member, is attached. There is a charger 2
When the air sent to the air supply unit 2 comes into contact with the air passage forming portion 73c, the air is further heated. Therefore, the generation of ozone in the corona discharge charger 22 can be reduced more efficiently. .

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be appropriately made within the scope of the gist of the present invention.

[0021]

According to the image forming apparatus of any one of claims 1 and 2, it is possible to surely prevent image deterioration due to ozone. Further, according to the image forming apparatus of the second aspect, it is possible to heat the air fed to the corona discharge charger without providing a separate heat source.

[0022]

[Brief description of drawings]

FIG. 1 is a schematic front view showing the internal structure of an embodiment of a color image forming apparatus according to the present invention.

FIG. 2 is a rear view of the image forming apparatus with a case 10 removed.

FIG. 3 is an image carrier unit 20 removed from the apparatus main body.
A perspective view showing the blower unit 70.

FIG. 4 is an exploded perspective view of a blower unit.

[Explanation of symbols]

12 Control Board (Heat Source) 22 Corona Discharge Charger 26 Photoconductor and Intermediate Transfer Belt Drive Motor (Heat Source) 44 Developing Device Drive Motor (Heat Source) 63 Fixing Unit Drive Motor (Heat Source) 71 Blower Fan 72 Duct

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H027 JA02 JB13 JB14 JB15 JB19                       JC02 JC08 JC16 JC18                 2H200 FA01 GA23 GA34 GA47 GA49                       GB12 GB22 GB25 GB44 HA02                       HA12 HA28 HB03 HB12 JA02                       JC03 JC07 LA31 LB21 LB25                       LB28

Claims (2)

[Claims] 1. An image forming apparatus comprising: a corona discharge charger provided with a blowing fan for blowing air through a duct; and at least a part of the duct or the blowing fan is arranged close to a heat source in the image forming apparatus. 2. The blower fan includes a paper conveyance system drive motor, a fixing device drive motor, an image carrier drive motor, an intermediate transfer member drive motor, a developing device drive motor, a heat fixing roller, and a control board in the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is arranged close to at least one of the above.