JPH09114183A - Friction electrifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To electrify an object to be electrified without providing an electrifying power source with a simple structure at a low cost. SOLUTION: This friction electrifying device is provided with an elastic roller 3 kept in contact with a photoreceptor 2 and a roller 4 with a brush rotatable in contact with the elastic roller 3. The elastic roller 3 is rubbed by the roller 4 with a brush to be friction-electrified, and the photoreceptor 2 kept in contact with the elastic roller 3 is electrified. The photoreceptor 2 can be electrified without requiring an electrifying power source, and this device can be manufactured at a low cost because of its simple structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a triboelectrification apparatus for electrifying an object to be electrified by triboelectrification, and more particularly, to electrify a photoconductor of an electrophotographic image forming apparatus such as a copying machine, a laser printer, a facsimile machine. A suitable triboelectric charging device.

[0002]

2. Description of the Related Art For example, an image forming apparatus such as an electrostatic copying machine or a printer is equipped with a charging device for charging a photosensitive member which is a member to be charged. The contact roller charging type charging device, which charges the charging roller (elastic roller) by contacting the charging roller, is attracting attention because it requires a smaller voltage than the conventional charging method using corona discharge.

Such a contact roller charging type charging device is provided with a mechanism for cleaning the charging roller because the charging function is deteriorated when toner adheres to the charging roller (for example, Japanese Patent Laid-Open No. 6-194931). See the bulletin). In addition, the charging roller has a two-layer structure, and the outermost surface layer resistance is "10 ⁵ Ω ≤ outermost surface layer resistance ≤ 10 ⁹ Ω", and the outermost surface layer resistance is "1/10 ≤ outermost surface layer resistance / other The resistance of the layer "is also used (for example, JP-A-5-303260).
Reference).

[0004]

However, such a contact roller charging type charging device requires a power source for applying a voltage to the charging roller, which leads to an increase in cost and a corresponding increase. However, there is a problem in that the entire device becomes large because a space for housing the device is required. Further, since the charging efficiency represented by "charging potential / applied voltage" changes depending on the surface temperature of the charging roller and decreases as the temperature becomes lower, it is necessary to correct the applied voltage according to the temperature.

Further, if toner adheres to the surface of the charging roller and becomes dirty, the charging function is deteriorated, so that a mechanism for cleaning the charging roller is required, and the mechanism is accordingly complicated. There were also problems. The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to charge a body to be charged without providing a power source for charging. Then, it should be possible to realize it at a low cost with a configuration as simple as possible.

[0006]

In order to achieve the above-mentioned object, the present invention is provided with a charging member that comes into contact with an object to be charged and a roller with a brush that is rotatable in contact with the charging member. Provided is a frictional charging device that rubs a charging member to frictionally charge it, and charges a body to be charged with which the charging member contacts. According to this frictional charging device, the charging member can be frictionally charged only by rotating the brush roller and rubbing the charging member. Since the charging member is in contact with the member to be charged, The charged body is charged. Further, the charging member may be an elastic roller that rotates in contact with the body to be charged.

Further, a rotatable photosensitive member having a charged conductive layer formed by coating on its surface is used as a member to be charged, and a friction member slidingly contacting the charged conductive layer of the photosensitive member is provided, and the friction member and the photosensitive member are charged. There is also provided a triboelectrification device that triboelectrically charges the charged conductive layer by friction with the conductive layer. According to this frictional charging device, the frictional conductive layer can be frictionally charged only by the friction member slidingly contacting the charged conductive layer of the photoreceptor. Therefore, the structure can be further simplified by eliminating the need to provide the charging member.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a frictional charging device for explaining an embodiment of the invention together with a photoconductor of an image forming apparatus. This frictional charging device 1 is shown by an arrow A.
Elastic roller 3 that is a charging member that rotates in the direction of arrow B while contacting the surface of the drum-shaped photoconductor 2 that rotates in the direction
And a roller with a brush 4 which is rotatable in the arrow C direction against the rotational direction of the elastic roller 3 at the contact position while contacting the elastic roller 3, and the roller with the brush 4 is provided.
Thus, the surface of the elastic roller 3 is rubbed to be triboelectrically charged, and the surface of the photoconductor 2 which is a member to be charged in contact with the elastic roller 3 is charged.

The elastic roller 3 is formed by integrally mounting an elastic roller portion 6 on the outside of a cored bar 5 made of metal such as stainless steel. As the elastic roller portion 6, for example, a rubber roller or a plastic roller is used.
As the rubber material, polyurethane rubber, silicone rubber, natural rubber, butadiene rubber, isoprene rubber, ethylene / propylene rubber or the like is used.

If plastic is used,
Polyamide, epoxy resin, polyethylene, Teflon, etc. are used. The roller with brush 4 is one in which a large number of brushes 8 are planted on the outside of a cored bar 7 made of metal such as stainless steel. As the material of the brush 8, wool fiber, silk fiber, cotton fiber, nylon fiber, polyester fiber or the like is used. Then, the metal plate electrode 12 is brought into contact with the surface of the roller with brush 4, and the metal plate electrode 1
2 is grounded via a resistor 11.

According to the frictional charging device 1, the brush roller 4 is rotated while being in contact with the elastic roller 3 to frictionally charge it, and the charged elastic roller 3 is rotated while being in contact with it. The photoconductor 2 can be charged. Therefore, the conventional contact roller charging type charging device is shown in FIG. 3, but the DC power source 1 for applying a voltage to the charging roller 13 which is such an elastic roller.
You don't need 5.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described. The elastic roller 3 shown in FIG. 1 is formed by integrally mounting an elastic roller portion 6 made of isoprene rubber on a core metal 5 made of SUS303. Then, the elastic roller 3 is attached to the photosensitive member 2 made of an organic optical semiconductor (OPC).
The photoconductor 2 is pressed against by an urging force of a coil spring or the like (not shown), and the photoconductor 2 is rotated in the direction of arrow A so that the photoconductor 2 can be rotated together with the direction of arrow B.

The roller with brush 4 is formed by implanting a large number of brushes 8 made of wool fibers on a core metal 7 made of SUS303, and the tip of the brush 8 contacts the elastic roller portion 6 of the elastic roller 3. Arrange to do. Then, the brushed roller 4 is rotated in the arrow C direction by the motor 9 capable of controlling the number of rotations independently. In the frictional charging device 1, when the motor 9 is rotated to cause the brush roller 4 to vigorously contact and rotate with the surface of the elastic roller 3, the surface of the elastic roller 3 becomes -1500.
Triboelectrically charged to V. Further, the surface of the photoconductor 2 rotating while contacting the charged elastic roller 3 is -800V.
Charged.

[0014]

[Table 1]

Since the surface of the photoconductor 2 is neutralized by the static elimination lamp 10, when the portion charged by the elastic roller 3 rotates once and rotates again to the position where it comes in contact with the elastic roller 3, The surface potential has dropped to almost 0V. In this way, the static elimination lamp 10
The surface of the photoconductor 2 whose charge has been removed by is recharged to −800 V by the frictionally charged elastic roller 3, and the cycle is repeated.

[0016]

[Table 2]

In this embodiment, the brush roller 4 is used.
Was charged to +1000 V, but the metal plate electrode 12 was brought into contact therewith, and the metal plate electrode 12 was grounded via the resistor 11 to remove the charge, so that stable charging characteristics were obtained. The wool fiber used for the brush 8 was “The Welsh” (British wool) manufactured by Renown Co., Ltd. The isoprene rubber used for the elastic roller portion 6 of the elastic roller 3 was Nipol (IR) of Zeon Corporation. Table 1 shows combinations of preferable materials for the elastic roller 3 and the brush roller 4.
Further, the photoconductor 2, the elastic roller 3, and the brush roller 4
Table 2 shows the outer diameter of each roller and their preferred rotation conditions.
Shown in

By the way, as shown in FIG. 2, an elastic layer 26 is integrally mounted on the outside of a core metal 25, and a surface layer 27 is formed on the outside of the elastic layer 26. In the case of the elastic roller 23, the temperature of the voltage applied to the charging roller 23 needs to be corrected because the charging potential of the surface of the photosensitive member has a large temperature-humidity dependency. Since the charging device 1 has little temperature-humidity dependency, it is not necessary to correct the temperature-humidity of the applied voltage, but there are two methods for performing this.

<Method 1> A decrease in the charging potential is corrected by increasing the rotation speed of the roller with brush 4. <Method 2> The metal plate electrode 12 is intermittently brought into contact with or separated from the surface of the roller with brush 4 for correction.

The elastic roller portion 6 of the elastic roller 3 according to this embodiment has only a rubber layer and needs only to have an insulating property, so that the required function is small. Further, since the brush 8 of the roller with brush 4 is constantly in frictional contact with the elastic roller portion 6, dirt on the surface of the elastic roller 3 is cleaned by the brush 8, so that the surface of the elastic roller 3 is cleaned. The cleaning member 16 as shown in FIG. 3 is not necessary.

Further, the rotation direction of the brush roller 4 in FIG. 1 may be the clockwise direction in FIG. Further, the elastic roller 3 may be provided with a surface layer for improving the durability of the surface thereof. Depending on the type of the photosensitive member, positive charging may be required. In that case, the "+" side in the triboelectric charge train may be selected as the material of the elastic roller 3, and the "-" side may be selected as the material of the roller with brush 4.
On the contrary, in the case of negative charging, the material of the elastic roller 3 may be selected from the "-" side and the material of the brush roller may be selected from the "+" side.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a photoconductor 21 having a surface coated with a charged conductive layer 22 is used.
A roller with a brush 4'rotating while contacting the charging conductive layer 22 of the photoconductor 21 is provided, and the charging conductive layer 22 is frictionally charged by friction between the brush roller 4'and the charging conductive layer 22 of the photoconductor 21. Let That is, the charging function of the elastic roller is provided on the photosensitive body 21 side.

Insulation is required in the case of the elastic roller 3 of the first embodiment described above, but conductivity is required in the charging conductive layer 22 of this embodiment. Different from the material used. Further, since chargeability is also required, a semiconductive material is preferable as a material used for the charge conductive layer 22. A silk fabric is used for the brush 8 of the roller with brush 4 '. Then, the photosensitive member 21 and the roller with brush 4'are rotated under the conditions shown in Table 3 to perform charging, and the charging conductive layer 22 of the photosensitive member 21 is -90.
It could be charged to 0V. In Table 3, the rotation direction of the roller with brush 4'may be counterclockwise.

[0024]

[Table 3]

An experiment was conducted by replacing the brush roller 4'with a blade-shaped friction member 34 as shown in FIG. 5, but the same effect was obtained. In addition, in this example, the charged conductive layer 22 is formed of Epichromer CG manufactured by Daiso Co., Ltd.
And the silk fabric used for the brush 8 of the roller with brush 4'was Kanebo Nylon "nylon / silk fabric".

[0026]

As described above, according to the frictional charging device of the present invention, the brush roller rubs the elastic roller to frictionally charge the elastic roller, and the charged elastic roller comes into contact therewith. Since the charged body to be charged is charged, the charged body can be charged without requiring a power source for charging. And since it has a simple structure, it can be manufactured at low cost.

Further, according to the friction charging device in which the charged conductive layer is formed on the surface of the photosensitive member and the friction member is brought into sliding contact with the charged conductive layer, in addition to the power source for charging the photosensitive member, the elastic roller is used. Since a charging member such as is not required, the structure can be further simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a frictional charging device for explaining an embodiment of the present invention together with a photoconductor of an image forming apparatus.

FIG. 2 is a schematic diagram showing an example of a conventional contact roller charging type charging roller.

FIG. 3 is a schematic diagram showing a conventional contact roller charging type charging device that requires a DC power supply.

FIG. 4 is a schematic view for explaining a second embodiment of the frictional charging device according to the present invention.

FIG. 5 is a schematic diagram for explaining a triboelectrification apparatus using a blade-shaped friction member.

[Explanation of symbols]

 1: Friction charging device 2, 21: Photoconductor 3: Elastic roller (charging member) 4, 4 ': Roller with brush (friction member) 22: Charging conductive layer 34: Friction member

Claims (3)

[Claims] 1. A charging member that comes into contact with an object to be charged and a roller with a brush that can rotate in contact with the charging member are provided, and the roller with a brush rubs the charging member to frictionally charge the charging member. A triboelectrification apparatus characterized in that the contacted body to be charged is charged. 2. The friction charging device according to claim 1, wherein the charging member is an elastic roller that rotates in contact with the body to be charged. 3. A rotatable photoconductor having a charged conductive layer formed by coating on the surface thereof is used as an object to be charged, and a friction member slidingly contacting the charged conductive layer of the photoconductor is provided, the friction member and the photoconductor. The frictional charging device is characterized in that the charging conductive layer is frictionally charged by friction with the charging conductive layer.