JPH05181295A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To remove discharge product ion caused by corona discharge and to prevent image flowing in an electrophotographic device by installing a fiber cleaner for dusting off the surface of a photosensitive body in between an electrostatic charging means and a cleaner. CONSTITUTION:The number of photosensitive body 1 using times is counted by a counter 15, for example, a cylinder 13 is actuated every 100 to 50,000 sheets and the fiber cleaner 12 is pushed against the surface of the photosensitive body 1 at a prescribed pressure so as to dust off the surface. The fiber cleaner 12 is obtained by sticking a cloth such as nylon and cotten, etc., on the surface of a plastic core, and the surface is recessed and brought into tight contact with the surface of the photosensitive body. By making the pressure for bringing the fiber cleaner into contact with the surface of the photosensitive body >=1kg/cm<2>, the discharge product ion on the surface of the photosensitive body can be wiped off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus such as a copying machine, a printer or a facsimile, and particularly to removing an ion such as a nitrate ion or an ammonium ion generated on a photoconductor by corona discharge by a charging means to form an image. The present invention relates to an electrophotographic device that prevents flow.

[0002]

2. Description of the Related Art Conventionally, in the electrophotographic photoreceptor, in order to prevent damage due to corona discharge in the charging process and physical and chemical damage due to contact with other members in the electrophotographic process, the surface of the photoreceptor is prevented. Is provided with a protective layer. For example, a-S
In the case of the i-based photoreceptor, a surface protective layer such as a-SiC is provided.

The surface protective layer is an insulating layer or a high resistance layer close to it, but discharge products such as nitrate ions and ammonium ions are generated by corona discharge in the electrophotographic process, particularly corona discharge from the charger. These ions are generated, for example, when ozone generated by discharge oxidizes nitrogen in the air to generate NOx, and NOx reacts with adsorbed water on the photoconductor to form nitrate ions. Nitrate ion,
When ammonium ions or the like adsorb to the surface protective layer of the photoconductor and absorb moisture in the atmosphere, the electric resistance of the surface of the surface protective layer decreases, the photoconductor cannot maintain an electrostatic latent image, and image deletion occurs. ..

To prevent image deletion, Japanese Patent Laid-Open No. 51-65
941, JP-A-52-129434, JP-A-53-
No. 32744 and the like propose that a photosensitive member is heated by a heater to evaporate adsorbed water. Although the heating of the photosensitive member by the heater is a commonly used method, this method has a problem that the toner adheres to the surface protective layer. Further, heating the photoconductor with the heater significantly increases the power consumption of the electrophotographic apparatus and further extends the waiting time at the start of use from cold.

JP-A-61-112153 and JP-A-62 / 62
No. 119567 and Japanese Patent Application Laid-Open No. 63-60477 propose to remove the discharge product ions with an abrasive. However, the use of an abrasive damages the surface protective layer and deteriorates the developing characteristics when the abrasive is mixed with the toner. Further, there is a problem that active metal atoms and metal oxide molecules appear on the surface from the surface protection layer by polishing, and the adsorption of discharge products is rather likely to occur.

JP-A-2-293884 and JP-A-2-2
No. 93885 proposes to remove the discharge products adhering to the surface of the photoconductor by using water, a polyhydric alcohol, or a derivative thereof. However, it is not preferable to bring a wet process into a dry process because the structure of the electrophotographic apparatus becomes complicated.

In addition to this, Japanese Patent Publication No. 50-2105
It is proposed to wipe off the residual toner with a fiber roller. However, the fiber roller here is not for the removal of discharge product ions and the cleaning process used is wet. Japanese Utility Model Publication No. 57-13566 proposes a cleaner including a collecting roller, a blade, and a fiber brush. However, the fiber brush here is for removing the toner and not for removing the discharge product ions.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to remove discharge products such as nitrate ions and ammonium ions adsorbed on a surface protective layer to prevent image deletion in an electrophotographic apparatus.

[0009]

The present invention comprises a conductive support, an a-S
Around the photoconductor in which the i-based photoconductive layer and the surface protective layer are laminated,
In an electrophotographic apparatus provided with a charging unit, an exposing unit, a developing unit, a transferring unit, and a residual toner cleaner, a surface protective layer of the photoconductor is provided between the charging unit and the cleaner. A fiber cleaner for removing the discharge product ions accompanying the corona discharge by the charging means, like wiping with air.
Is provided and the fiber cleaner is brought into contact with the photoconductor at a pressure of 1 kg / cm ² or more.

The present invention is also for removing the discharge product ions associated with corona discharge in the charging means so as to wipe the surface protective layer of the photoreceptor between the charging means and the cleaner. A fiber cleaner, and a mechanism for moving the fiber cleaner between a position in contact with the photoconductor and a position separated from the photoconductor, and the fiber cleaner is exposed intermittently. It is characterized in that it comes in contact with the body and is wiped dry.

Here, the fiber cleaner includes woven cloth, non-woven cloth, felt, brush, pad, towel cloth,
Alternatively, any material such as paper can be used, and the material is plant fiber such as cotton, linen, paper, absorbent cotton, animal fiber such as wool or rabbit hair, horse hair, silk, or nylon. Synthetic resin fibers such as polyester, acrylic, etc. are used.

The pressure for contacting the fiber cleaner with the surface protective layer is 1 kg / cm ² or more, more preferably 3 kg / cm ^2.
cm ² or more, more preferably 5 kg / cm ² or more, and the upper limit is, for example, 10 kg / cm ² or less because pressing with excessively strong pressure is not preferable. The pressure of the fiber cleaner is important, and the discharge product ions can be wiped off only when the pressure is set to 1 kg / cm ² or more.

The fiber cleaner may be always brought into contact with the surface protective layer, but it is preferable to intermittently protect the surface in order to prevent generation of fiber scraps and deterioration of the wiping ability due to dents in the cleaner. Contact the layers. The wiping frequency is, for example, once for every 100 copies to once for every 50,000 copies.

[0014]

In the present invention, the fiber cleaner is a-S.
The surface protective layer of the i-type photoreceptor is brought into contact with the surface protective layer at a pressure of 1 kg / cm ² or more to wipe off discharge product ions such as nitrate ions and ammonium ions. The wiping mechanism here is considered to generate an electric field by charging due to friction between the cleaner and the surface protective layer, and move the discharge product to the cleaner. Further, the fiber used for the cleaner contains a highly polar group, and also contains a hydrophilic group to absorb moisture in the air, so that a discharge can be easily generated from the surface protective layer to the fiber cleaner. The product ions move. The contact pressure between the fiber cleaner and the surface protective layer is important in order to move the discharge product ions by triboelectric charging. If this pressure is low, for example, the cleaner for removing residual toner in the conventional example may be used. Like 100
It was found that the discharge product could not be wiped off at about g / cm ² .

According to the present invention, the photosensitive member is hard and has a long life.
-Si type photoconductor is used. The a-Si type photoreceptor is hard,
Since the a-SiC layer of the surface protective layer also has a high hardness, it does not wear even if it is rubbed with a fiber cleaner under a strong pressure.
On the contrary, in the case of an OPC photoreceptor or an a-Se photoreceptor having a low hardness and a short life, the accumulation of discharge product ions itself does not pose a problem.

Wiping off the discharge product ions in the present invention is a dry type, and is easily adapted to an electrophotographic apparatus. Further, removing the discharge product ions means that the heating temperature of the photoconductor may be low. This means that the power consumption of the electrophotographic apparatus can be reduced and the waiting time at the start of operation can be reduced.

[0017]

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to the examples.

FIG. 1 shows an outline of the embodiment. In the figure, 1 is an a-Si photoconductor, and 2 is Al, Ni, Fe, C.
Conductive supports such as u and Au, and 3 are a-Si photoconductor layers. As shown in FIG. 2, the a-Si photoconductor layer 3 is a-Si.
Charge injection blocking layer 21, a-Si photoconductive layer 22, a-Si
C surface protective layer 23. Charge injection blocking layer 21
May not be provided, and the photoconductive layer 22 may be a single layer or two layers of a charge generation layer and a charge transport layer. The surface protective layer 23 includes
Other than a-SiC, any insulating material or high resistance material can be used.

Returning to FIG. 1, 4 is a charger, 5 is an exposure beam, 6 is a developing device, 7 is a transfer charger, and 8 is a separation charger. 9 is a toner cleaner, 10 is a rotating roller, and 11 is a blade.

Reference numeral 12 is a fiber cleaner, and here, a cloth of nylon, cotton or the like is attached to the surface of a plastic core material, and the surface is made concave so that it is brought into contact with the surface of the photoconductor 1. The surface width of the cleaner 12 is 10 mm here,
The width of the circumference of the photoreceptor 1 having a diameter of 108 mm was 1/60.
The contact width is preferably about 1/10 to 1/100 of the circumference of the photoreceptor 1. The length of the cleaner 12 is made equal to the effective charging width charged by the charger 4. 13 is a pneumatic cylinder, 14 is a pneumatic pump, 15 is a counter,
The counter 15 counts the number of times the photoconductor 1 is used,
For example, the cylinder 13 is operated every 100 to 50,000 sheets, and the fiber cleaner 12 is pressed against the surface of the photoconductor 1 with a predetermined pressure. Instead of the pneumatic cylinder 13, any fiber cleaner moving means such as a spring or a motor may be used. 1
Reference numeral 6 is an optical static elimination lamp.

The shape, type and material of the fiber cleaner 12 are arbitrary. In addition to cotton and nylon, hemp and silk,
Paper, wool, animal hair such as rabbits and horses, polyester, acrylic,
Can be used. One of the advantages of the fibrous shape is that the surface protection layer 23 is less damaged than in the case of the blade shape. 3 to 5,
The modification of the fiber cleaner 12 is shown.

In the fiber cleaner shown in FIG. 3, a fiber cloth 32 is attached around a plastic core material 31 to form a cleaner. In the cleaner of FIG. 4, the rollers 41, 43, 4
4 is used to feed the cloth 42. In this embodiment, the cloth used for wiping is not reused, and a new surface is always brought into contact with the photoconductor 1. This is advantageous in that the discharge product ions that have moved to the cloth 42 by wiping are not transferred to the photoconductor 1 again. In the cleaner of FIG. 5, the roller-5
The discharge product ions are wiped off using the cloth 52 wrapped around 1. In FIGS. 4 and 5, the roller-4
The diameter of 3,51 is 1/5 to 1/10 of the diameter of the photoconductor 1.
The peripheral speed is preferably 1.5 to 5 times that of the photoconductor 1 when the photoconductor 1 rotates in the same direction, and is 1/30 of the peripheral speed of the photoconductor 1 when the photocatalyst 1 rotates in the opposite direction. ~ 3 times.

[0023]

[Test Example 1] Aluminum pipe support 2 (diameter 108
(mm × 360 mmL) is precisely cleaned, and then set in a vacuum vapor deposition apparatus, and a high-frequency glow discharge using SiH4 as a main raw material gas is used to form a charge injection blocking layer 21 having a thickness of 2 μm and a thickness of 25 μm on the support 2. The a-Si photoconductive layer 22 was formed. The discharge conditions are vacuum degree of 0.5 Torr and temperature of 2
It was set to 50 ° C. Then, on the photoconductive layer 22, a thickness of 0.5 was obtained by high frequency glow discharge using SiH4 and CH4 gas.
A 4 μm a-SiC surface protection layer 23 was formed. The discharge conditions were a vacuum degree of 0.35 Torr and a temperature of 250 ° C.

Using this photoreceptor 1, 200,000 sheets of electrostatic running were carried out with the apparatus shown in FIG. In the fiber cleaner 12,
A cotton soft pad was used. Photoconductor 1 while running
Was heated to 44 ° C. by a heater (not shown). After running 200,000 sheets, a copy test was performed in an environment of 32 ° C. and relative humidity of 85%. The results are shown in Table 1. As is clear from the table, by wiping with a pressure of 1 kg / cm ² or more,
Image deletion can be prevented.

[0025]

[Table 1] Removal of fiber cleaner and discharge product ion Fiber cleaner and presence / absence of image deletion after 200,000 sheets of pressure 3 kg / cm ² Wipe off every 10,000 sheets 2 minutes after heater is turned on 2 kg / not resolved in cm ² 1 million copies 60 minutes after heater activation wiping solved 0.5 kg / cm ² 1 million copies every at eliminating 1 kg / cm ² 1 million copies heater on 5 minutes after wiping every 3 minutes after the heater on wiping each 0.5 kg / cm ² Always wiped off 60 minutes after the heater was turned on, it did not disappear. No fiber cleaner was found. 120 minutes after the heater was turned on, it did not disappear.

[0026]

Test Example 2 Using the photoconductor 1 used in Test Example 1, the change in the heating temperature of the photoconductor 1 necessary for preventing image deletion was examined with and without the fiber cleaner 12. In the embodiment, the photoconductor 1 is heated to 44 ° C., and the fiber cleaner is used for 3 k for every 20,000 sheets.
The discharge product ions were wiped off at a pressure of g / cm ² . In the example, the image deletion did not occur even after the 200,000-sheet test. On the other hand, in the conventional example in which the fiber cleaner 12 was not used, it was necessary to heat at 55 ° C. or higher in order to prevent image deletion.

[0027]

According to the present invention, the discharge product, which is the main factor of the image deletion, is wiped off with a cloth, cotton or the like, so that the image deletion can be prevented even when it is used for a long period of time or in high humidity. Since an a-Si system having a high surface hardness is used for the photoconductor, damage due to the pressure during wiping does not occur. Since the discharge product ions are removed by the fiber cleaner, the photoconductor may be heated at a low temperature or not heated, which saves the power consumption of the electrophotographic apparatus and reduces the waiting time at the start of the operation. Can be shortened. Further, if the fiber cleaner is intermittently brought into contact with the photoconductor, it is possible to prevent the generation of fiber scraps and prevent the deterioration of the wiping efficiency due to the dent of the cleaner.

[Brief description of drawings]

FIG. 1 is a diagram showing an electrophotographic apparatus according to an embodiment.

FIG. 2 is a cross-sectional view of a main part of a photoconductor used in an example.

FIG. 3 is a side view of the fiber cleaner of the embodiment.

FIG. 4 is a side view of the fiber cleaner of the embodiment.

FIG. 5 is a side view of the fiber cleaner of the embodiment.

[Explanation of symbols]

 1 Photoconductor 2 Conductive Support 3 Photoconductor Layer 4 Charging Device 5 Exposure Beam 6 Developer 7 Transfer Charger 8 Separation Charger 9 Toner Cleaner 12 Fiber Cleaner 13 Air Cylinder 14 Pneumatic Pump 15 Counter 21 Charge Injection Blocking Layer 22 Photoconductive layer 23 Surface protective layer 31 Core material 32, 42, 52 Cloth 41, 43, 44, 51 Roller

Claims (2)

[Claims] 1. A charging means, an exposing means, a developing means, a transferring means, and a residual toner cleaner are provided around a photoconductor in which an a-Si photoconductive layer and a surface protective layer are laminated on a conductive support.
In an electrophotographic apparatus provided with a charger, discharge product ions associated with corona discharge in the charging unit so as to wipe the surface protective layer of the photoconductor between the charging unit and the cleaner. An electrophotographic apparatus, characterized in that a fiber cleaner for removing the above is provided, and the fiber cleaner is brought into contact with the photoconductor at a pressure of 1 kg / cm ² or more. 2. A charging unit, an exposing unit, a developing unit, a transferring unit, and a residual toner clearing unit around a photoconductor in which an a-Si photoconductive layer and a surface protective layer are laminated on a conductive support.
In an electrophotographic apparatus provided with a charger, discharge product ions associated with corona discharge in the charging unit so as to wipe the surface protective layer of the photoconductor between the charging unit and the cleaner. And a mechanism for moving the fiber cleaner between a position in contact with the photoconductor and a position separated from the photoconductor, for removing the fiber cleaner. An electrophotographic apparatus, wherein the electrophotographic apparatus is intermittently brought into contact with a photosensitive member and wiped dry.