JPH0916046A - Cleaning device for electrophotographic image forming device - Google Patents

Abstract

PURPOSE: To prevent a blade and a photoreceptor from being damaged and further to prevent the photoreceptor from being damaged by a foreign matter caught by an elastic blade for removing toner by providing a scavenging member whose tip is projected forward further than the elastic blade so as to scavenge scraped toner. CONSTITUTION: This cleaning device is attached to be inclined so that a crossing angle ϕ formed by the supporting member 63 of the elastic blade 61 with a photoreceptor belt 10 may satisfy the relation of ϕ>π/2 on a cleaning side. Then, the blade 61 projected from the supporting member 63 and bent to the cleaning side is set so that its crossing angle θ formed with the belt 10 may satisfy the relation of θ/ϕ. Furthermore, a film-like elastic member is stuck and fixed on the opposite surface of the blade 61 to the cleaning side of the belt 10 in a state where its tip is projected as the toner scavenging member 62. Therefore, the toner is always secured at the tip of the blade 61, so that a friction coefficient between the blade 61 and the belt 10 is prevented from getting larger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for an electrophotographic image forming apparatus, and more particularly to a cleaning device for an electrophotographic image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer.

[0002]

2. Description of the Related Art Electrophotographic copying machines, electrophotographic printers, etc.
In general, an image forming apparatus adopting an electrophotographic system is configured such that a photosensitive drum is the center of charge and a charger that uniformly charges the surface of the photosensitive drum, and the charged surface of the photosensitive drum is exposed according to image information and electrostatically charged. An exposure device for forming a latent image,
A developing device that develops the electrostatic latent image into a toner image, a transfer device that transfers the toner image to the supplied recording paper, and a recording paper on which the toner image has been transferred to pass the toner image onto the recording paper. And a heat fixing device for fixing to

On the other hand, as one method for forming a color image in this type of image forming apparatus, a photosensitive surface is formed on a flexible film such as a polyethylene terephthalate film, and a different color is formed on the surface of an endless photosensitive belt. An attempt was also made to form a color toner image on the surface of the intermediate transfer drum by forming a toner image of (yellow, magenta, cyan, black) and transferring these four toner images so as to be superimposed on the surface of the intermediate transfer drum. Has been.

In such an image forming apparatus, since the surface of the photoconductor is repeatedly used, it is cleaned by a cleaning device having a fur brush, a magnet roll, a blade or the like as a cleaning body. Among them, a blade cleaning method is often used, which is advantageous in terms of cost and occupied volume of the apparatus.

However, in the blade cleaning method,
Depending on the contact angle and contact pressure between the elastic blade and the photoconductor, the friction coefficient between the two increases, and the elastic blade catches on the photoconductor and turns over, the elastic blade falls off from the blade support member, and the blade tip is scratched. However, there was a problem that the photoconductor was damaged.

Further, since the elastic blade easily catches the irregular shaped carrier contained in the developer carrier or foreign matter such as paper powder floating in the machine and holds the foreign matter, the photosensitive member may be damaged. there were.

A technique of transferring a toner image formed on a photosensitive member to a transfer medium and then cleaning it with an elastic blade is disclosed in, for example, Japanese Patent Application Laid-Open No. 54-34340.

Further, JP-A-63-64074 and JP-A-1-161289 disclose techniques relating to prevention of toner scattering in an image forming apparatus.

However, the techniques described in JP-A-63-64074 and JP-A-1-161289 are related to the prevention of toner scattering, as described above, and are described below in the present invention. Further, it does not relate to prevention of damage to the blade or the photoconductor due to an increase in the friction coefficient between the elastic blade and the photoconductor, and further to prevention of the damage to the photoconductor due to the foreign matter being caught in the elastic blade.

[0010]

As described above, in the image forming apparatus adopting the electrophotographic method and employing the blade cleaning method for cleaning the photosensitive member, as described above, the cost and the apparatus can be reduced. However, it is important to prevent damage to the blade and the photoconductor due to an increase in the friction coefficient between the elastic blade and the photoconductor, and to prevent the photoconductor from being scratched due to the foreign matter being caught by the elastic blade. .

An object of the present invention is to prevent damage to the blade and the photoconductor due to an increase in the friction coefficient between the elastic blade and the photoconductor, and further to prevent the photoconductor from being scratched due to the inclusion of foreign matter in the elastic blade, and to extend its life. An object of the present invention is to provide a cleaning device for an electrophotographic image forming apparatus, which can be realized.

[0012]

In the cleaning device of an electrophotographic image forming apparatus, the tip of an elastic blade is brought into contact with the surface of a photoconductor and the toner remaining on the surface of the photoconductor is scraped off by the elastic blade. , Scraping from the photoconductor by projecting the tip from below to the top of the elastic blade for removing toner, which is in contact with the photoconductor, on the side opposite to the surface in contact with the photoconductor, This is achieved by providing an elastic film-shaped toner collecting member that collects the dropped toner.

[0013]

According to the above construction, since toner can be supplied as a lubricant between the elastic blade and the photosensitive member, it is possible to prevent the friction coefficient between the elastic blade and the photosensitive member from increasing. Therefore, it is possible to prevent the elastic blade from being reversed, peeled off, and scratched, and also to prevent the photosensitive member from being scratched.

Further, the toner deposited on the toner collecting member is floating between the elastic blade and the photosensitive member in the following foreign matter, that is, the irregular carrier contained in the carrier of the developer and the inside of the machine. In the case of a foreign material such as paper dust or a photosensitive belt having a seam, the foreign material adhering to the seam is prevented from entering, so that the photoconductor can be prevented from being scratched.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows the overall structure of the color laser printer. In the center of the frame 100, there is provided an endless photosensitive belt 10 having a photosensitive surface formed on a flexible film such as a polyethylene terephthalate film. , Drive roller 1
1 and the driven rollers 12 to 14 are stretched around and rotatably installed.
An exposure device 25 for forming an electrostatic latent image on the photosensitive belt 10 by image-exposing the photosensitive belt 10 by turning on / off a laser according to information from the host, and a developing device 22 for yellow color.
Y, magenta developing device 22M, cyan developing device 22C, black developing device 22K, and photosensitive belt 10
A cleaning device 24 and the like for cleaning the above are provided. The developing devices 22Y to 22K for the respective colors rotatably support developing rollers 23Y to 23K that form magnetic brushes made of a developer.

On the left side of the photosensitive belt 10, there is provided an intermediate transfer drum 30 which is in contact with the photosensitive belt 10. A paper cassette 41 for accommodating the paper 40 and a paper feed roller 42 are provided below the frame body 100. Frame 100
On the left side of the inside, there are a registration roller 43, a transfer roller 27, a charge eliminator 28, a conveyance guide 44, a fixing device 51, and a paper discharge roller 5.
2 are provided. A paper discharge tray 53 is provided on the upper side of the frame body 100. A drum cleaner 35 is provided above the intermediate transfer drum 30 so as to be separable from and in contact with the surface of the intermediate transfer drum 30. The peeling claw 32 is provided for peeling the sheet 40 that is about to be attracted to the intermediate transfer drum 30.

Next, the operation of this color laser printer will be described.

Since the object of the present invention is to improve the cleaning device for the photosensitive member, detailed description on the electrostatic latent image formation, development and transfer will be omitted.

When color image printing (monochrome image printing is almost the same) is started, the laser generated from the exposure device 25 is turned on / off according to the image information for each color sent from the host, and each color is printed on the photosensitive belt 10. To form an electrostatic latent image of. The developing devices 22Y to 22K develop corresponding electrostatic latent images to form toner images. The toner images of the respective colors are transferred onto the intermediate transfer drum 30 in an overlapping manner,
The color toner image is synthesized by the above. Photosensitive belt 10
The toner image that cannot be completely transferred to the intermediate transfer drum 30 and remains on the belt is scraped off by the elastic blade 61 (FIGS. 1 and 3) protruding from the cleaning device 24 and contacting the photosensitive belt 10.

On the other hand, the paper 40 is fed from the paper cassette 41 through a paper feed roller 42, and the registration roller 4
It is transported up to 3. The registration roller 43 starts rotating in synchronization with the movement timing of the color toner image on the intermediate transfer drum 30, and sends the sheet 40 to the transfer roller 27.

The transfer roller 27 is energized at the same time as the transfer roller 27 moves in the direction of contacting the intermediate transfer drum 30 when the sheet 40 reaches the transfer position, and presses the sheet 40 against the color toner image on the intermediate transfer drum 30. The color toner image is transferred to the paper 40. At this time, the sheet 40 is charged by the voltage application of the transfer roller 27, and the intermediate transfer drum 3
It tries to be electrostatically attracted to the intermediate transfer drum 30 in relation to the potential of zero. The static eliminator 28 acts to neutralize a part of the electric charge charged on the sheet 40 in order to reduce the electrostatic attraction force. Since the leading edge of the paper 40 with the electrostatic attraction force reduced in this way forms a slight gap with the intermediate transfer drum 30, the peeling claw 32 enters the gap and the paper 40.
Be sure to peel off. After that, the paper 40 is fixed by the fixing device 51 and is discharged to the paper discharge tray 53.

In the electrophotographic color laser printer as described above, the cleaning device 24 and the photosensitive belt 10 are used.
Of the elastic blade 61 and the photosensitive belt 10 are not damaged. Therefore, the elastic film 62 is provided at the tip of the elastic blade 61 to collect the toner scraped off from the photosensitive belt 10,
By ensuring that toner is always present at the tip of the elastic blade 61, it is possible to prevent an increase in the friction coefficient between the elastic blade 61 and the photosensitive belt 10 and prevent foreign matter from being caught between the elastic blade 61 and the photosensitive belt 10. Has been done.

As shown in FIG. 1, the cleaning device 24
Is the support member 63 of the elastic blade 61 and the photosensitive belt 10.
The support member 63 is mounted so as to be inclined so that the intersecting angle φ with the relation φ> π / 2 on the cleaning side.
Elastic blade 61 protruding from the side and flexing toward the cleaning side
It is installed so that the intersection angle θ with the photosensitive belt 10 has a relationship of θ> φ. Further, on the elastic blade 61, a film-like elastic member is adhered and fixed as a toner collecting member 62 to the surface opposite to the cleaning side of the photosensitive belt 10 with the tip protruding. As the toner collecting member 62, an elastic member such as a polyethylene terephthalate film or urethane rubber is used. This is because the elastic blade 61 is attached to the elastic blade 61, so that if the elastic member is not an elastic member, the elasticity of the elastic blade 61 may be robbed and the cleaning performance may be deteriorated.

The toner 65 remaining without being transferred to the intermediate transfer drum 30 rides on the photosensitive belt 10, reaches the cleaning device 24, is scraped off by the elastic blade 61, and adheres to the tip surface of the elastic blade 61. When the toner 65 further arrives, it is deposited on the toner collecting member 62 provided at the tip of the elastic blade 61. The accumulated toner 65 acts as a lubricant for the photosensitive belt 10 and the elastic blade 61, and prevents the friction coefficient between them from increasing.

In the electrophotographic image forming apparatus, the blade cleaning method as described above is adopted in terms of cost and structure. Furthermore, in terms of cleaning performance,
The arrangement method as shown in FIG. 1, that is, the elastic blade 61
A so-called counter method is often used in which the intersecting angle φ between the supporting member 63 and the photosensitive belt 10 is φ> π / 2 on the cleaning side. Although this method has high cleaning power, the coefficient of friction between the photoconductor and the elastic blade increases, the tip of the elastic blade bites into the photoconductor, scratches the tip of the elastic blade, or further advances and the elastic blade is reversed. Otherwise, it may cause a malfunction such as locking the photoconductor.

Therefore, conventionally, when a new elastic blade is attached, fine resin powder or toner is applied as a lubricant to the tip of the elastic blade or the surface of the photosensitive member to prevent the friction coefficient between them from increasing.

However, the above-mentioned lubricant gradually decreases, and eventually the above-mentioned failure occurs.

The present invention is intended to solve this problem.

In the two-component developing system, not only toner but also carrier is often attached to the photosensitive belt 10. This carrier rides on the photosensitive belt 10,
When it reaches the cleaning device 24, it is usually scraped off by the elastic blade 61.

However, the photosensitive belt 10 has a seam 70 which is a joining mark by welding so as to form an endless belt. The step of the seam 70 has almost the same size as that of the carrier. Due to this step, the carrier may pass between the elastic blade 61 and the photosensitive belt 10, while the carrier is bitten by the elastic blade 61. If it stays at a certain position, the surface of the photosensitive belt 10 is rubbed, and a scratch is generated on the surface of the photosensitive belt 10. This phenomenon may occur not only by the carrier but also by paper dust or other foreign matter floating in the machine.

On the other hand, the toner collected and accumulated by the toner collecting member 62 can prevent foreign matters such as the above-mentioned carriers from catching on the elastic blade 61 in front of the elastic blade 61. Therefore, the photosensitive belt 10 is not damaged.

FIG. 3 is a side view of a photosensitive belt unit equipped with the cleaning device shown in FIG.

The photosensitive belt 10 is stretched and driven by the driven rollers 12 and 13 and a driving roller (not shown). In the cleaning device 24, a support member 63 is rotatably attached around a rotation fulcrum 66, and a spring 64 makes contact with the photosensitive belt 10 with a constant load. The photosensitive belt 10 is in contact with an intermediate transfer drum 30 (not shown) between the driven rollers 12 and 13. The remaining toner 65 that cannot be completely transferred passes through the driven roller 13 and reaches the cleaning device 24. Then, the toner 65 is scraped off by the elastic blade 61 and collected by the toner collecting member 62. In this way, the collected toner acts as a lubricant and acts as a wall for preventing foreign matter from entering, so that the photosensitive belt 10 and the elastic blade 61 are prevented from being scratched and the unit has a longer life. it can.

[0035]

As described above, according to the present invention, since toner can be supplied as a lubricant between the elastic blade and the photosensitive member, it is possible to prevent an increase in the friction coefficient between the elastic blade and the photosensitive member. . Therefore, it is possible to prevent the elastic blade from being reversed, peeled off, and scratched, and also to prevent the photosensitive member from being scratched.

Further, the toner deposited on the toner collecting member is suspended between the elastic blade and the photosensitive member in the following foreign matter, that is, the irregular carrier contained in the carrier of the developer or the inside of the machine. In the case of a foreign material such as paper dust or a photosensitive belt having a seam, the foreign material adhering to the seam is prevented from entering, so that the photoconductor can be prevented from being scratched.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a cleaning device according to the present invention.

FIG. 2 is a vertical sectional side view showing the overall configuration of a color laser printer.

FIG. 3 is a side view of a photosensitive belt unit including the cleaning device shown in FIG.

[Explanation of symbols]

10 ... Photosensitive belt, 11 ... Drive roller, 12-14 ... Followed rollers, 19M, 19C ... Development gap setting member, 21 ...
Charger, 22Y, 22M, 22C, 22K ... Developing device,
23Y, 23M, 23C, 23K ... Developing roller, 24 ...
Cleaning device, 25 ... Exposure device, 27 ... Transfer roller, 28 ... Static eliminator, 30 ... Intermediate transfer drum, 32 ... Separation claw, 35 ... Drum cleaning, 40 ... Paper, 41 ... Paper cassette, 42 ... Registration roller, 51 ... Fixing device, 5
2 ... Paper discharge roller, 53 ... Paper discharge tray, 61 ... Elastic blade, 62 ... Toner collecting member, 63 ... Support member, 64 ... Spring, 65 ... Residual toner, 66 ... Rotation fulcrum, 70 ... Photosensitive belt 10 Seam, 100 ... Frame.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Saito 1-1-1 Higashitaga-cho, Hitachi-shi, Ibaraki Hitachi, Ltd. Information & Video Media Division

Claims (4)

[Claims] 1. A cleaning device for an electrophotographic image forming apparatus in which the tip of an elastic blade is brought into contact with the surface of a photoconductor and the toner remaining on the surface of the photoconductor is scraped off by the elastic blade. On the opposite side of the surface of the elastic blade for removing toner that comes into contact with the photoconductor with the photoconductor,
Further, an electrophotographic image forming apparatus is provided, which is provided with an elastic film-shaped toner collecting member for collecting the toner scraped off from the photoconductor by projecting its tip forward from the toner removing elastic blade. Equipment cleaning device. 2. The cleaning device for an electrophotographic image forming apparatus according to claim 1, wherein the toner collecting member is a synthetic resin or a rubber material. 3. The cleaning device for an electrophotographic image forming apparatus according to claim 1, wherein the photosensitive member is a cylindrical photosensitive drum. 4. The photosensitive member according to claim 1 or 2,
A cleaning device for an electrophotographic image forming apparatus, which is an endless photosensitive belt having a photosensitive surface formed on a flexible film such as a polyethylene terephthalate film.