JPH0619272A - Electrostatic charging brush device - Google Patents

Abstract

PURPOSE:To provide the e1ectrostatic charging brush device which can reduce unpleasant vibration noises as to an electrostatic charging brush device which is used for the electrostatic charging of the electrostatic recording medium of an electrophotographic system image forming device. CONSTITUTION:This electrostatic charging brush device is constituted by fitting conductive base cloth 9, equipped integrally with brush fiber 8 gathered radially closely, onto a conductor 6 which applies an externally applied voltage to the brush fiber 8, which is electrostatically charged in contact with the electrostatic recording medium 1. A vibration-insulating layer 7 which provides superior vibration insulation and does not impede the application of the voltage from the conductor 6 to the brush fiber is provided between the base cloth 9 and conductor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging brush device used for charging an electrostatic recording medium in an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, a contact charging method in which a member to which a voltage is applied from the outside is brought into contact with an electrostatic recording medium for charging is used in an electrophotographic image forming apparatus or the like. This contact charging method, compared to the widely used corona charging method,
Compared to several KV when the power source is corona charging, contact charging has a low voltage around 1 KV, and no ozone is generated.
It has various advantages that the charging potential depends on the applied voltage and does not depend on the process speed and the electrostatic capacity of the electrostatic recording medium.

Roller charging and brush charging are known as contact charging methods. For roller charging, a roller having a function-separated multilayer structure has been put into practical use. this is,
This was because there was no other way to obtain the desired elastic force, resistance value, and surface smoothness than by using a multilayer structure, and therefore it could not be denied that the cost would increase. On the other hand, brush charging does not need to be multi-layered unlike roller charging, and elasticity and resistance values can be set to desired values with one type of brush.

The contact charging type driving method includes a method of applying a constant voltage, a method of printing a constant current, and a method of superimposing an AC voltage on the constant voltage. The constant voltage method is susceptible to the environment and has a problem that the charging potential is lowered in a low temperature and low humidity environment. The constant current method has a problem that current is concentrated in a defective portion of the photosensitive drum (electrostatic recording medium), and the photosensitive drum and the contact charger are burned.

Finally, in the case of a method of superimposing an AC voltage on a constant voltage, there is no environmental fluctuation of the constant voltage and there is no burning of the photosensitive drum of a constant current. Therefore, as the driving method, a method in which alternating current is superimposed is effective.

[0006]

In the contact charging method, charging is performed by contacting the electrostatic recording medium, so that friction occurs at the contact point between the electrostatic recording medium and the contact charger. Friction
It is caused by rotation of the electrostatic recording medium, rotation of the contact charger, or both. Further, when a voltage, particularly an AC voltage, is applied to the contact charger, the charger vibrates remarkably. Then, from these causes, an unpleasant vibration sound is generated.

An object of the present invention is to provide a charging brush device (contact charger) capable of reducing unpleasant vibration noise.

[0008]

In order to achieve the above object, in the present invention, a conductive base cloth integrally provided with densely projecting brush fibers is used as a voltage applied from the outside and containing at least an AC component. In a charging brush device that is mounted on a conductor for flowing into the brush fiber, and charges the brush fiber by contacting the brush fiber to an electrostatic recording medium, between the base cloth and the conductor, the brush from the conductor. The structure (first structure) is characterized in that a vibration-damping layer having excellent vibration absorption property that does not hinder the flow of voltage to the fibers is provided.

Further, in the charging brush device of the above-mentioned first structure, the region of the vibration-proof layer having the vibration absorbing effect includes the frequency band of the AC component of the voltage applied from the outside (the first structure). 2 configuration).

In the charging brush device having the first structure, the vibration-proof layer is made of acrylic urethane (third structure).

[0011]

An anti-vibration layer is provided between the base cloth and the conductor, and the anti-vibration layer is used to prevent unpleasant noise when the apparatus is used, for example, noise caused by friction between the electrostatic recording medium and the brush fiber, and applied voltage The noise and the like caused by the vibration of the brush fiber mainly due to the AC component therein are reduced. This latter sound reduction effect is particularly remarkable in the case of the second configuration. The charging ability is not inferior to conventional products.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is an explanatory view of the structure and operation of the charging brush device of this embodiment, in which 1 is a photosensitive drum (electrostatic recording medium),
2A is a charging brush device and 3 is a power supply. The photoconductor drum 1 is formed by forming a photoconductor layer 5 on an outer peripheral surface of a base body 4 made of aluminum. In this example, the photoconductor layer 5 is formed of an organic photoconductor. The outer diameter of the photosensitive drum 1 is 40 mm, and the photosensitive drum 1 rotates at a predetermined speed in the direction of the arrow, which is 70 mm / s in this example.

As shown in detail in FIG. 1A, the charging brush device 2A has a cylindrical conductor 6 made of metal such as SUS403.
A vibration-proof layer 7 is joined to the outer periphery of the above, and a belt-shaped base cloth 9 in which conductive brush fibers 8 are raised is spirally wound around it without any gap. In this state, the brush fibers 8 integrated with the base cloth 9 form a radially dense brush layer. The charging brush device 2 having such a configuration is arranged so that the brush fibers 8 come into contact with the photoconductor drum 1 and rotates in the arrow direction in FIG.

The depth of the brush layer was 5 mm. In addition, the brush fiber is provided with conductivity by uniformly dispersing carbon particles in the rayon fiber, and the resistance value is selected to be 10 ⁹ Ω per fiber. Fiber thickness is 6D / F
And the fineness is 600/100 D / F.

The power source 3 is for applying a voltage to the charging brush device 2A, and can apply a voltage obtained by superimposing an AC voltage and a DC voltage. In this example, the AC voltage V _AC is a peak-to-peak voltage V _PP = 1200V and a frequency 800H.
z, the DC voltage is set to _VDC = -650V.

The antivibration layer 7 is formed of a material having excellent antivibration properties, for example, a urethane sheet (Everlite LR damper VD manufactured by Bridgestone Corporation). Since the urethane sheet is an insulating sheet, a part of the vibration-proof layer 7 is cut in order to electrically connect the base cloth 9 and the conductor 6. 7a is a cut portion. It should be noted that the cut portion is not necessary when the vibration damping layer is a conductor. By providing such an anti-vibration layer 7, the photosensitive drum 1 and the brush fiber 8 when the charging brush device is used
It is possible to reduce noise and the like caused by the friction. When the device of this example is compared with the conventional product, the noise, which was 50 dB in the related art, is reduced by 75% to 13 dB or less. Further, good charging was possible without a decrease in charging ability.

When the band having the sound absorbing effect of the anti-vibration layer includes the frequency range of the AC component of the voltage applied to the charging brush device, mainly the AC component of the voltage applied to the charging brush device is included. This is more effective because it can reduce the sound and the like caused by the vibration of the brush layer.

Although the rotary type charging brush device is described in the above description, the present invention is also applicable to the fixed type charging brush device 2B shown in FIG. 1 (B). The charging brush device 2B is configured by sequentially providing a vibration damping layer 11 and a base cloth 13 having a brush layer of brush fibers 12 on a conductor 10 so that the tips of the brush fibers 12 come into contact with the photosensitive drum. Used by being fixed. Also in this case, when the vibration-proof layer 11 is an insulating sheet, the cut portion 11a is provided so that the base cloth 13 and the conductor 10 are electrically connected.

In the above description, an example in which the vibration-proof layer is a urethane sheet has been described, but the microcell polymer sheet Polon made by Inoac Corporation or the US EAR. SC company vibration absorption grommet (for high frequency absorption)
Can also be used.

[0021]

As described above, according to the present invention, noise can be significantly reduced without lowering the charging ability.

[Brief description of drawings]

1 is a structural explanatory view of a charging brush device according to an embodiment of the present invention, FIG. 1 (A) shows a rotary charging brush device, and FIG.
(B) shows a fixed charging brush device.

FIG. 2 is a diagram illustrating the configuration and operation of the charging brush device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum (electrostatic recording medium) 2A, 2B Charging brush device 3 Power supply 6,10 Conductor 7,11 Anti-vibration layer 8,12 Brush fiber 9,13 Base cloth

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshiaki Sakamoto 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Tetsuro Nakajima 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited

Claims (3)

[Claims] 1. A conductive base cloth (9) integrally provided with densely projecting brush fibers (8), wherein a voltage containing at least an AC component applied from the outside is applied to the brush fibers (8).
In a charging brush device, which is mounted on a conductor (6) for flowing into the electrostatic recording medium and charges the brush fiber (8) to an electrostatic recording medium, the charging is performed between the base cloth (9) and the conductor (6). A charging brush device, characterized in that a vibration-damping layer (7) having an excellent vibration absorbing property that does not hinder the flow of voltage from the conductor (6) to the brush fiber (8) is provided. 2. The charging brush device according to claim 1, wherein a region of the vibration-proof layer (7) having a vibration absorbing effect includes a frequency band of an AC component of a voltage applied from the outside. Brush device. 3. The charging brush device according to claim 1, wherein the vibration-proof layer (7) is made of acrylic urethane.