JPH07325524A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To provide an electrophotographic device where residual toner on a photoreceptor drum is removed without damaging the surface of the photoreceptive drum and the deterioration of image quality is restrained. CONSTITUTION:This device is equipped with the photoreceptive drum 1, a transfer roller 5, and a cleaning mechanism 6 for the photoreceptive drum. The cleaning mechanism 6 is equipped with a destaticizing light irradiation means 7 irradiating residual toner T on the drum 1 with destaticizing light K, a rotating brush 8 installed on the downstream side of the irradiation means 7, a discharged toner housing case 6A freely rotatably supporting the brush 8 and housing the toner T, and a charge applying means (toner removing plate) 9 installed in the housing case 6A and applying the charge having a reverse polarity to the drum 1 on the brush 8. The brush 8 is formed of an insulating material having property that it is electrostatically charged to have the reverse polarity to the drum 1 because of the contact friction with the drum 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus,
In particular, the present invention relates to an electrophotographic apparatus provided with a waste toner storage case.

[0002]

2. Description of the Related Art FIG. 2 shows a main part of a conventional electrophotographic printer. In the conventional example shown in FIG. 2, a charging brush 52 as a charging unit uniformly charges the photosensitive drum 51, and then a part of the charging is erased by a laser beam B to form a latent image. After the latent image is developed by the developing unit 54, the toner image is transferred onto the paper P by the transfer roller 55, and the paper P is passed through a fixing device to be fixed.

On the other hand, the toner T remaining on the photosensitive drum 51
The charge on the photosensitive drum 51 is weakened by the static elimination light K. As a result, the residual toner T on the photosensitive drum 51 weakens the binding force with the photosensitive drum 51, and the cleaning unit 56
Move to.

In the cleaning section 56, a flexible blade 61 which is in contact with the photosensitive drum 51 scrapes off the toner T remaining on the photosensitive drum 51.

[0005]

In each step of the above-mentioned conventional example, the charging brush 52 is used as a unit for uniformly charging the photosensitive drum 51, and the transfer roller 55 is used as a toner image transfer unit. Since all of these units are in contact with the photosensitive drum 51, the performance may be significantly reduced depending on the contamination of the photosensitive drum 51. Particularly, the deterioration of the charging ability due to the dirt of the charging brush 52 has a disadvantage that the image quality is significantly deteriorated. Also,
The contact type toner cleaning has a disadvantage that the surface of the photosensitive drum is easily damaged.

[0006]

It is an object of the present invention to improve the disadvantages of the conventional example, especially to remove the toner remaining on the surface of the photosensitive drum.
It is an object of the present invention to provide an electrophotographic apparatus in which the surface of the photosensitive drum is effectively removed without being damaged and the deterioration of image quality is suppressed.

[0007]

According to the present invention, there is provided a photosensitive drum, and a transfer roller which is provided in parallel with the photosensitive drum and transfers the developing toner on the photosensitive drum onto a predetermined sheet.
And a cleaning mechanism for the photosensitive drum, which is attached to the photosensitive drum and has a function of removing the residual toner on the photosensitive drum.

A cleaning mechanism is provided with static elimination light irradiating means for irradiating the residual toner on the photosensitive drum with static elimination light, a rotary brush provided downstream of the static elimination light irradiating means for rotating in contact with the photosensitive drum, and this rotation. A waste toner storage case that rotatably supports the brush and stores the toner that has separated from the photosensitive drum, and a charge adding unit that is provided in the waste toner storage case and adds a charge having a polarity opposite to that of the photosensitive drum to the rotating brush. It is composed of and. This aims to achieve the above-mentioned object.

[0009]

[Operation] Toner T and other residues remaining on the photosensitive drum 1 are weakened by the static elimination light K to weaken the binding force with the photosensitive drum 1 and move to the cleaning process.
Here, the residue is scraped off from the photosensitive drum 1 by the electrostatic force of the insulating rotary brush 8. When the photosensitive drum 1 is an organic photosensitive drum (OPC), the bristles of the brush are selected as the material that is subjected to frictional charging opposite to the surface material.

On the other hand, the residue attached to the rotary brush 8 is
Toner removal plate 9 installed on the downstream side of rotation of the rotating brush 8.
Collected and removed by. The same polarity as the charging characteristic of the rotating brush 8 is applied to the toner removing plate 9 as a bias voltage in advance.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In the embodiment shown in FIG. 1, the photosensitive drum 1
And a transfer roller 5 which is provided in parallel with the photosensitive drum 1 and transfers the developing toner T attached to the photosensitive drum 1 onto a predetermined sheet, and a residual toner T which is provided in the photosensitive drum 1 and on the photosensitive drum 1 is removed. And a photosensitive drum cleaning mechanism 6 having the function of

The cleaning mechanism 6 irradiates the residual toner T on the photosensitive drum 1 with the discharging light K for discharging the discharging light K.
And a rotary brush 8 which is provided on the downstream side of the static elimination light irradiation means 7 on the photosensitive drum 1 and rotates in contact with the photosensitive drum 1, and the rotary brush 8 is rotatably supported and is separated from the photosensitive drum 1. A waste toner storage case 6A for storing the toner T and a toner removing plate 9 as a charge adding means for adding a charge having a polarity opposite to that of the photosensitive drum 1 to the rotating brush 8 provided in the waste toner storage case 6A are provided. It is equipped with.

The rotating brush 8 is formed of an insulating material having a property of being charged to a polarity opposite to that of the photosensitive drum 1 due to contact friction with the photosensitive drum 1.

More specifically, the processes of charging, exposing, developing, transferring, discharging, and cleaning are arranged around the photosensitive drum 1.

In this case, a fixed charging brush 2 is used for charging.
Is used, and the charging voltage V _B is applied. After charging, the surface charge is lost by selective irradiation of the laser beam B, and a latent image is formed. This latent image is developed into a toner image by the developing unit 4. This toner image is transferred onto the paper P which is a recording medium by the transfer roller 5 to which the transfer bias V _T is applied. The transferred toner image is fixed by a fixing device (not shown), whereby printing is completed.

Next, the operation of the above embodiment will be described. The toner T and other residues remaining on the photosensitive drum 1 are weakened in the binding force with the photosensitive drum 1 by the static elimination light K, and move to the cleaning process. Here, the residue is scraped off from the photosensitive drum 1 by the electrostatic force of the insulating rotary brush 8. Photosensitive drum 1 is an organic photosensitive drum (OPC)
In this case, the bristles of the brush are selected as the material that is oppositely charged by friction with respect to the material of the surface.

For example, when polycarbonate (PC) is used as the material of the surface of the OPC, a material such as nylon, rayon, PVA (polyvinyl alcohol), or wool is used, and the resistance value is 10 ⁸ [Ω]. ]
It is adjusted to have the above insulating properties. At this time, the charging brush 2 has a positive charging characteristic with respect to the negative charging of the photosensitive drum 1, so that it is possible to electrostatically and reliably remove the residual toner and the residue such as scraps of the OPC.

On the other hand, the residue attached to the rotary brush 8 is
Toner removal plate 9 installed on the downstream side of rotation of the rotating brush 8.
Collected and removed by. The same polarity as the charging characteristic of the rotating brush is applied to the toner removing plate 9 as a bias voltage in advance.

In the above example, the OPC is used for the photosensitive drum 1, but when an inorganic material is used, the same effect can be obtained by selecting the brush in consideration of the triboelectric chargeability.

The same applies when a charging roller is used instead of the charging brush 2, corona transfer is used as the transfer unit, and AC corona is used instead of the charge removing light.

Further, the shape of the toner removing plate 9 may be a simple flat plate, but if it is a comb shape, the toner removing effect is further improved. In addition, not only a plate shape but also a roller shape, a rotating plate, or the like may be used.

On the other hand, in the case of a copying machine, the laser light is replaced by the reflected light of the original, and the characteristics of the photosensitive drum and the polarity of the toner are changed, but a similar configuration can be adopted.

[0024]

Since the present invention is constructed and functions as described above, it is possible to completely remove the residual toner and other residues on the photosensitive drum, especially the scraps of the photosensitive drum. Therefore, it is possible to provide an unprecedented excellent electrophotographic apparatus in which a stable and high-quality image can be obtained for a long period of time without contaminating other members in contact with the photosensitive drum.

[Brief description of drawings]

FIG. 1 is a sectional view showing a position embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example.

[Explanation of symbols]

 1 Photosensitive Drum 2 Charging Brush B Laser Light 4 Development Unit 5 Transfer Roller 6 Cleaning Mechanism for Photosensitive Drum 6A Waste Toner Storage Case 7 Electrification Light Emission Means 8 Rotating Brush K Electrification Light P Paper (Recording Medium) T Toner

Claims (4)

[Claims] 1. A photosensitive drum, a transfer roller which is provided in parallel with the photosensitive drum to transfer the developing toner attached to the photosensitive drum onto a predetermined sheet, and a residual toner which is provided in the photosensitive drum and remains on the photosensitive drum. In an electrophotographic apparatus having a photosensitive drum cleaning mechanism having a removing function, the cleaning mechanism is configured to irradiate the residual toner on the photosensitive drum with an erasing light, and an erasing light irradiating unit. A rotary brush which is installed on the downstream side and rotates in contact with the photosensitive drum, a waste toner storage case which rotatably supports the rotary brush and stores toner separated from the photosensitive drum, and a waste toner storage case An electronic image forming apparatus, characterized in that the rotating brush is equipped with a charge adding unit for adding a charge having a polarity opposite to that of the photosensitive drum. Apparatus. 2. The electrophotography according to claim 1, wherein the rotating brush is formed of an insulating material having a property of being charged to a polarity opposite to that of the photosensitive drum due to contact friction with the photosensitive drum. apparatus. 3. The electrophotographic apparatus according to claim 1, wherein the charge adding means is a toner removing plate provided in contact with the rotating brush. 4. The electrophotographic apparatus according to claim 1, wherein the charge adding means is a toner removing roller provided in contact with the rotating brush.