JPH06124791A - Static elimination of charged material and static eliminator - Google Patents

Abstract

PURPOSE:To eliminate the occurrence of an abnormal image caused by the lack of static elimination and conveyance failure caused by excessive static elimination by obtaining always a proper static elimination quantity in simple constitution. CONSTITUTION:Brush fiber bendable in a direction of a transfer paper 103 by electrostatic force according to electric charge of the transfer paper 103, is provided, and a static eliminating brush 104 arranged in the positional relationship by which clearance between the brush fiber and the transfer paper is changed by a bending condition of the brush fiber, is provided. The brush fiber of the static eliminating brush 104 is bent by the electrostatic force according to the electric charge of the transfer paper 103, and the clearance between it and the transfer paper 103 is changed, and a static elimination quantity is adjusted, and static elimination is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for removing static electricity from charged objects.
The present invention relates to a method and a device for neutralizing a charged object that eliminates the electric charge of a transfer sheet after separation.

[0002]

2. Description of the Related Art As a conventional static eliminator for removing charges on a transfer paper after transfer / separation in an electrophotographic apparatus, there is, for example, a static eliminator for removing static charge on a transfer paper (charged object). In this method, a static elimination brush is arranged vertically opposite to the transfer paper, and the static electricity is eliminated by generating an appropriate discharge between the brush fiber and the charged material. In other words,
The charge removal amount of the transfer paper is adjusted by setting the gap (distance) between the brush fiber and the transfer paper to an appropriate value.

[0003]

However, according to the conventional static elimination method and static elimination device using the static elimination brush, the static elimination brush is arranged vertically opposite to the charged object, and between the brush fiber and the charged object. Since the charge removal amount of the charged object is adjusted by the gap (distance), if the charge of the charged object is not constant, it is necessary to strictly adjust the gap to maintain an appropriate charge removal amount, and the configuration is complicated. There was a problem that became.

Further, when used as a charge eliminating device for a transfer paper after transfer / separation, it is difficult to maintain an appropriate charge removing amount because the type of transfer paper and the environment change, and the material of the brush fiber is It was necessary to take measures such as devising the electrical characteristics of, and installing an electric circuit separately from the ground.

If the proper amount of charge removal cannot be maintained, the following problems will occur. For example, when the capacity of the transfer paper increases in a low temperature and low humidity environment, the charge density on the transfer paper increases and the surface potential rises. An abnormal discharge is likely to occur between a metal plate that is electrically attracted to improve transportability, and as a result, an abnormal image is likely to occur. Also, if the charge is removed too much,
Since the transfer paper will not be attracted to the metal plate,
It becomes easy to cause conveyance failure.

The present invention has been made in view of the above, and an object thereof is to always obtain an appropriate amount of charge removal with a simple structure.

Further, the present invention has been made in view of the above, and it is an object of the present invention to eliminate the occurrence of an abnormal image due to insufficient static elimination and the conveyance failure due to excessive static elimination.

[0008]

In order to achieve the above-mentioned object, the present invention provides a method for removing static electricity of a charged object by using a static elimination brush, and in accordance with the charge of the charged object, the static elimination brush is used. The brush fiber of (1) is bent by electrostatic force to change the gap between the brush fiber and the charged object, and the charge removal amount is adjusted to remove the charge.

Further, in order to achieve the above object, the present invention provides a static eliminator for eliminating charges on a transfer paper after transfer / separation in an electrophotographic apparatus, in which electrostatic charge is applied to the transfer paper by an electrostatic force corresponding to the charge on the transfer paper. Has brush fibers that flex in any direction, and
It is an object of the present invention to provide a static eliminator composed of static eliminator brushes arranged in a positional relationship in which the gap between the brush fibers and the transfer paper changes depending on the degree of bending of the brush fibers.

When the gap between the charge removal brush and the transfer paper is set to about several mm and the brush fiber is a cantilever in the above-mentioned configuration, the brush fiber has a formula (W of flexure of the cantilever). It is desirable that the EI / L ^{3 of} _max = PL ³ / 3EI) is in the range of 10 ⁻⁸ <EI / L ³ <10 ⁻⁶ [kgf / mm].

[0011]

In the method and apparatus for removing static electricity of a charged object according to the present invention, when the charged object approaches, the brush fiber of the static elimination brush bends according to the magnitude of the electrostatic force of the charged object, and the electrostatic force of the charged object is removed. The gap between the charged object and the charged object is reduced according to the size, and the charge on the charged object is eliminated. That is, when the charge amount of the charged object is large, the change in the gap is large and the charge removal amount is increased, and when the charge amount of the charged object is small, the change in the gap is small,
The amount of static electricity is reduced, and static electricity is always removed with an appropriate amount of static electricity.

[0012]

[Embodiment] In the following, as an example, a case of applying to a static eliminator for neutralizing charges on a transfer paper after transfer / separation of an electrophotographic apparatus,
An embodiment of a method for removing static electricity from a charged object and an apparatus for removing static electricity according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing the arrangement and configuration of the static eliminator of this embodiment. In the figure, 101 is a photoconductor of an electrophotographic apparatus, 102 is a transfer / separation charger, 10
3 is a transfer paper (charged object), 104 is a static elimination brush (static elimination device of the present invention), and 105 is a guide plate.

Here, as the brush fibers of the static elimination brush 104, Naslon Tow (SUS304) φ12 μm (manufactured by Nippon Seisen Co., Ltd.) is used, and the static elimination brush 104 is the transfer paper 1
It is placed almost parallel to 03 and grounded. Further, the relationship among the length L of the brush fiber, the second moment of area I, and the Young's modulus E is 10 ^-8 <EI / L ³ <10 ^-6 [kgf / mm]
It is set to the range of.

Although not shown, a grounded metal plate is arranged on the guide plate 105 after separation, so that the metal plate and the transfer paper 103 do not come into direct contact with each other, and the transportability is improved. Ribs of resin with a height of 2 mm are provided for improvement.

The operation of the above configuration will be described. The toner image formed on the photoconductor 101 is transferred to the transfer paper 103 by the discharge of the transfer / separation charger 102. At that time, the transfer paper 102 is charged by the discharge. When the transfer paper 103 after separation approaches the static elimination brush 104, an electrostatic force is exerted on the brush fibers and the brush fibers are attracted toward the transfer paper 103. In this embodiment, the static elimination brush 10
Since the brush fibers of No. 4 are not perpendicular to the transfer paper 103, the brush fibers are bent toward the transfer paper 103 by the electrostatic force.

As the brush fibers bend,
As shown in (b), the gap between the transfer sheet 103 (the distance between the brush fiber and the transfer sheet in the state without bending (3 mm) -the bending amount W of the brush fiber) is narrowed, so that the amount of charge removal is increased. The electric charge is removed to the extent that abnormal discharge does not occur between the guide plate 105 and the metal plate. At this time, the transfer sheet 103 has a sufficient amount of electric charge to be attracted to the metal plate.
Are satisfactorily conveyed along the guide plate 105.

Further, for example, when the charge density on the transfer paper 103 is small (the surface potential is low) in an environment such as high temperature and high humidity, the force with which the brush fibers are attracted becomes weak, so the amount of flexure W of the brush fibers W Becomes smaller (that is, the gap between the brush fiber and the transfer paper 103 is not narrowed), and the amount of static elimination becomes smaller.

Since the brush fibers of the static elimination brush 104 are conductive fibers, the electrical characteristics of the brush fibers are unlikely to change due to the environment. Therefore, the deflection amount W of the brush fiber is almost entirely determined by the charge density on the transfer paper 103. In other words, the charge density on the transfer paper 103 is large,
When it is desired to increase the static elimination amount, the deflection amount W increases and the static elimination amount increases. On the other hand, when the charge density on the transfer paper 103 is small and it is desired to reduce the static elimination amount, the bending amount W decreases and the static elimination amount decreases.

Further, by an experiment, the relationship among the length L of the brush fiber, the second moment of area I, and the Young's modulus E was calculated as 10
By setting in the range of ^-8 <EI / L ³ <10 ^-6 [kgf / mm], a moderate amount of deflection can be obtained by the electrostatic force generated by the electric charge that is normally applied on the transfer paper 103. It can be confirmed, in particular, EI / L ³ = 1 × 10 ^-7 [kg
f / mm] is good. In addition, the deflection amount W of the brush fiber
Can be calculated by the following cantilever beam deflection formula. W _max = PL ³ / 3EI where W _max : Deflection amount P: Load (electrostatic force here) I: Second moment of area E: Young's modulus L: Brush fiber length

Further, the above 10 ^-8 <EI / L ³ <10 ^-6
Within the range of [kgf / mm], the charge removal amount is well controlled without hindering the transfer sheet 103 from being conveyed. In this case, the flexure amount W exceeds 3 mm, and brush fibers may come into contact with the transfer paper 103, but the number is small, and
Since it is a soft fiber, it does not hinder the transfer paper 103 from being conveyed.

With the above-described structure and operation, the environment
Even if the temperature is changed from 10 ° C / 15% RH to 30 ° C / 90% RH, a certain amount of electric charge (to the extent that an abnormal image does not occur) can be left on the transfer paper 103 after static elimination, and an abnormal image can be displayed. It was possible to convey it along the guide plate without generating it.

[0023]

As described above, according to the method and apparatus for removing static electricity of a charged object of the present invention, the brush fibers of the static elimination brush are bent by the electrostatic force in accordance with the charge of the charged object and the gap between the charged object and the charged object is eliminated. To change and adjust the amount of static elimination to eliminate static electricity,
With a simple configuration, an appropriate amount of static elimination can always be obtained.
Further, it is possible to eliminate the occurrence of an abnormal image due to insufficient static elimination and the conveyance failure due to excessive static elimination.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the arrangement and configuration of a static eliminator of this embodiment.

[Explanation of symbols]

 101 Photoreceptor 102 Transfer / Separation Charger 103 Transfer Paper (Charged Material) 104 Eliminating Brush (Eliminating Device of the Present Invention) 105 Guide Plate

Claims (3)

[Claims] 1. A method of neutralizing a charge of a charged object by using a static elimination brush, wherein a brush fiber of the static elimination brush bends due to an electrostatic force in accordance with the charge of the charged object to form a gap between the static charge and the charged object. The method of removing static electricity by changing the charge and adjusting the amount of static charge to eliminate static electricity. 2. A static eliminator for eliminating charges of transfer paper after transfer / separation in an electrophotographic apparatus, having brush fibers which are bent in the direction of the transfer paper by an electrostatic force corresponding to the charges of the transfer paper, and A static eliminator comprising a static eliminator arranged in a positional relationship in which the gap between the brush fiber and the transfer paper changes depending on the degree of bending of the brush fiber. 3. The gap between the static elimination brush and the transfer paper is several meters.
When the brush fiber is a cantilever beam, the brush fiber has a cantilever beam deflection formula (W _max = PL ³ / 3EI: where W _max is the deflection amount, P
Is the load, I is the second moment of area, E is the Young's modulus, L is the length of the brush fiber), and EI / L ³ is 10 ⁻⁸ <EI / L ³
A fiber in the range of <10 ⁻⁶ [kgf / mm].
The static eliminator described.