JPH0453651Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a connection circuit for a brush charging device that charges a photoreceptor used in electrophotographic copying machines, printers, and the like.

[Conventional technology]

Conventionally, this type of device was developed by, for example, Japanese Patent Application Laid-Open No.
There is a brush charging device disclosed in Japanese Patent No. 29837, in which a large number of thin conductive fibers are bundled together in a holder to form a brush shape, and the conductive fibers are charged through a conductive base material provided in the holder. It has a structure in which the charging power source and the charging power source are connected.

The brush charging device thus formed is placed in an electrophotographic copying machine or the like, with the tip of the brush-like conductive fiber in contact with the surface layer of the photoreceptor.

The photoreceptor has a structure in which a conductive layer and a surface layer are formed on the conductive layer, and as the photoreceptor rotates, electric power is applied to the conductive fibers from a charging power source to form a predetermined surface layer on the photoreceptor pair. It was charged to a potential of

[Problem that the invention attempts to solve]

However, according to the conventional technology mentioned above,
If there is a scratch on the surface layer of the photoreceptor, the tip of the conductive fiber of the brush charging device will come into direct contact with the conductive layer under the surface layer of the photoreceptor, resulting in a shot state, which will damage the conductive base material. Since potential fluctuations occur, the surface layer of the photoreceptor cannot be charged uniformly, resulting in uneven charging. Furthermore, if the scratches are large and the contact time between the conductive fibers and the conductive layer becomes long, Joule heat is generated, and the conductive fibers are damaged by this Joule heat, which causes a problem in that printing quality deteriorates. .

Therefore, the present invention was devised to solve the above problem, and even if the conductive layer of the photoconductor and the conductive fibers of the brush charging device come into contact with each other due to scratches on the surface layer of the photoconductor, the conductive base material is not affected. The purpose of this method is to prevent damage to conductive fibers due to Joule heat by preventing potential fluctuations, and to improve printing quality by uniformly and stably charging the surface layer of a photoreceptor.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention bundles conductive fibers to form a brush shape, and connects the conductive fibers to a charging power source via a conductive base material.
and an electrophotographic brush charging device for charging the photoreceptor by bringing the conductive fiber into contact with the surface layer of a rotatable photoreceptor comprising a conductive layer and a surface layer, the charging power source and the conductive base material; A resistor for overcurrent prevention is interposed between the conductive fibers and the conductive layer of the photoreceptor, one of which is connected to the conductive base material and the other of which is connected to the conductive layer of the photoreceptor. A capacitor is provided to prevent voltage fluctuations of the conductive base material when the conductive base material becomes short-circuited.

[Effect]

With the configuration described above, first rotate the photoreceptor,
Applying power to the conductive fibers using a charging power source,
The surface layer of the photoreceptor that is in contact with the conductive fibers is charged.

At this time, if there is a scratch on the surface layer of the photoreceptor, the conductive fibers enter the scratch and come into contact with the conductive layer below the surface layer of the photoreceptor, but the resistance acts as an overcurrent prevention resistor and the capacitor accumulates. By discharging the electric charge that had been present, the current flowing from the charging power source to the conductive substrate is suppressed. This prevents large potential fluctuations from occurring in the conductive base material, and
Even if there are large scratches and the contact time between the conductive fiber and the conductive layer is long, the generation of Joule heat can be reduced, preventing damage to the conductive fibers due to Joule heat, and making the surface layer of the photoconductor uniform. It becomes possible to charge evenly, thereby improving printing quality.

〔Example〕

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

FIG. 1 is a cross-sectional view of the main parts and a connection diagram of this embodiment, and in the figure, 1 is a conductive base material made of an aluminum plate, etc., 2 is a conductive adhesive made of conductive rubber, etc.
Reference numeral 3 denotes a base fabric, which forms a layer, and a plurality of rows of conductive fibers 4 are attached to the base fabric 3 and the layer of conductive adhesive 2 from the side of the base fabric 3 to form a brush-like configuration. A brush charging device 6 is constructed in which the output side of a charging power source 5 of about -1000 V is connected to the static base material 1 for electrical continuity.

7 is the surface layer of the photoreceptor, 8 is a grounded conductive layer,
This conductive layer 8 is formed below the surface layer and along the surface layer. 9 is a scratch on the surface layer 7, and the conductive layer 8 is exposed from the scratch 9.

Reference numeral 10 denotes a capacitor of about 10 μF, one of which is connected to the conductive substrate 1 and the other to the conductive layer 8 of the photoreceptor, so that the conductive substrate 1 of the brush charging device 6 is connected to the conductive substrate 1 of the brush charging device 6 via this capacitor 10. and a conductive layer 8 below the surface layer 7 of the photoreceptor are electrically connected.

Further, 11 is a resistor of about 3 MΩ, and this resistor 11 is interposed between the charging power source 5 and the conductive base material 1.

Next, the operation of the above-mentioned configuration will be explained.

First, the photoreceptor is rotated, and power is applied to the conductive fibers 4 from the charging power source 5 of the brush charging device 6, thereby charging the surface layer 7 of the photoreceptor that is in contact with the tips of the conductive fibers 4.

During this charging, if the scratches 9 on the surface layer 7 are long in the circumferential direction of the photoreceptor, the scratches 9
A portion of the conductive fiber 4 enters into the conductive layer 8 and comes into contact with the conductive layer 8 for a long time. In other words, the conductive fiber 4 and the conductive layer 8 are in a short-circuit state, and a current is about to suddenly flow from the charging power source 5, but at this time, the resistor 11 becomes a resistor for preventing overcurrent, and the conductive base material 1 suppresses excessive current from flowing to the At the same time, the capacitor 10 releases an appropriate amount of charge accumulated during normal operation to the conductive substrate 1, thereby preventing the voltage of the brush charging device from decreasing. This suppresses the current of the charging power source 5 and suppresses potential fluctuations in the conductive base material 1 of the brush charging device 6, thereby significantly reducing generation of Joule heat, and this Joule heat causes the conductive fibers 4 to 4. prevent damage.

In addition, if the scratch 9 is a minute pinhole or the like, the contact time between the conductive fiber 4 and the conductive layer 8, that is, the short-circuit time, is short because the photoreceptor is rotating. As in the previous case, resistor 11
Since the potential fluctuation of the conductive substrate 1 is suppressed by the capacitor 10 and the capacitor 10, the surface layer 7 of the photoreceptor is uniformly charged without any unevenness.

FIG. 2 is a diagram showing the potential of the conductive base material that occurs when the conductive fiber and the conductive layer come into contact. This example shows a case in which a capacitor 10 and a resistor 11 are provided.

As seen in this figure, in the case of the conventional example, the potential of the conductive base material 1 fluctuates rapidly and greatly, and in the example, it can be seen that the fluctuation is suppressed to a very small amount.

[Effect of idea]

As explained above, according to the present invention, a brush charging device having a structure in which electric power is applied from a charging power supply to conductive fibers formed in a brush shape through a conductive base material can be used as a photosensitive device for electrophotographic copying machines, etc. The conductive fibers are arranged in contact with the surface layer of the body, a resistor for overcurrent prevention is interposed between the charging power source and the conductive base material, and one side is connected to the conductive base material. In addition, if the surface layer of the photoreceptor is scratched due to the provision of a capacitor whose other end is connected to the conductive layer of the photoreceptor, even if the conductive fibers and the conductive layer come into contact, the resistance will be reduced. The capacitor acts as a resistor to prevent overcurrent, and the capacitor suppresses the current flowing to the conductive substrate by discharging charge, so there is no shortened state as in the conventional case, and the conductive fibers are damaged by Juul heat. can prevent damage.

Further, since potential fluctuations in the conductive base material can be prevented, the surface layer of the photoreceptor can be charged evenly and uniformly, resulting in the effect that printing quality can be improved.

[Brief explanation of the drawing]

Figure 1 is a cross section and connection diagram of the main parts of this embodiment, Figure 2
The figure is a diagram showing the potential of a conductive base material. 1... Conductive base material, 4... Conductive adhesive, 5...
... Charging power source, 7... Surface layer, 8... Conductive layer, 9...
...Scratch, 10...Capacitor, 11...Resistor.

Claims (1)

[Claims for Utility Model Registration] Conductive fibers are bundled into a brush shape, the conductive fibers are connected to a charging power source via a conductive base material, and the conductive fibers are connected to a conductive layer and a surface layer. In an electrophotographic brush charging device that charges a rotatable photoreceptor by contacting its surface layer, a resistor for preventing overcurrent is interposed between the charging power source and the conductive base material, and By connecting one side to the conductive base material and connecting the other side to the conductive layer of the photoconductor to provide a capacitor, the conductive fiber and the conductive layer of the photoconductor become conductive when the conductive layer is short-circuited. 1. A brush charging device for electrophotography, characterized in that it prevents voltage fluctuations in a magnetic base material.