JPS6157954A - Brush electrifier - Google Patents

Abstract

PURPOSE:To limit the flow of a current to a spark occurrence position by providing a contact consisting of conductive fibers and insulating fibers on a base through a high-resistance conductive layer. CONSTITUTION:A base cloth 2 is adhered to a base 4 through a high-resistance conductive adhesive layer 9, and a contact 1 is a mixed bundle of conductive fibers 10 and insulating fibers 11. When a brush electrifier is brought into contact with a perforated part of a photosensitive body 8, spark discharge is caused between conductive fibers 10 and a conductive layer 6. When a large current tries to flow from a bias power source 5, it is limited by the resistance part of the high-resistance conductive adhesive layer 9, and therefore, the large current is not flowed to conductive fibers 10, and spark discharge is not intensified, and the voltage of the bias power source is hardly dropped by spark discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to a brush charging device for charging a photoreceptor, etc. of an electronic V:electronic device.

2. Description of the Related Art A corona charging device is known as a device for uniformly charging the surface of a photoreceptor in an electrophotographic apparatus.

However, corona charging devices are dangerous because they use high voltage, and corona discharge characteristics are subject to large fluctuations due to external conditions (pressure, temperature, humidity, ventilation conditions), and ozone generated during discharge may cause damage to the surrounding environment. There are various problems such as damage to equipment.

Corona! To solve these problems! Brush charging devices using contact charging methods have been developed to replace mold devices.

For example, as shown in FIG. 3, a base fabric 2 on which a large number of contacts 1 are implanted in a brush shape is bonded to aluminum via a conductive adhesive layer 3. ), the base 4 is connected to a bias power supply 5, and a contactor is attached to the photoreceptor layer 7 of a photoreceptor 8, which has a photoreceptor layer 7 provided on the surface of conductive scrap 6 made of aluminum. A brush charging device charges a photoreceptor near F' by contacting it with a contact 1.

In other words, the contact I is made of conductive fibers, and a large number of them are implanted in the base $2 composed of warp threads and threads to form a brush shape, and each conductive fiber uniformly contacts the photoreceptor layer 7. The bias voltage applied to the base 4 by the bias power supply 5 is applied to the conductive fiber through the conductive adhesive layer 3, and when the tip of the fiber comes into contact with the photoreceptor F''!7, Become electrically charged.

Problems to be Solved by the Invention Even if the photoreceptor layer 7 has a diameter of 0.2B or less, the conductivity P:
If j6 is exposed, when this part comes into contact with the contact 1 made of conductive fibers, a spark discharge will occur between it and the conductive layer 6, causing a large current to flow. As the voltage of the source 5 drops, the charging potential of all the parts of the photoreceptor layer 7 that are in contact with the brush-shaped contact 1 decreases, so that normal charging is not possible and copies with normal image quality cannot be obtained. It disappears.

In addition, as the spark discharge is repeated, the hole described above gradually widens and the spark discharge becomes thicker and narrower, so the voltage drop mentioned above becomes larger and larger, and the drop in the charged potential becomes larger, causing the problem of poor image quality to become even worse. Become.

1jJffMeans and effects for solving the 1 point A contact made of conductive fibers and insulating fibers was provided on the base via a high resistance conductive layer to limit the flow of current to the point where sparks were generated. thing.

Example Members that are the same as those in the prior art have the same reference numerals and explanations will be omitted.

The base fabric 2 is adhered to the base 4 via the resistive conductive adhesive layer 9, and the contact 1 is a mixed bundle of conductive layer #10 and MR woven fibers 11. In reality, the conductive fibers 1o and the insulating fibers 11 are separated one by one.

In FIG. 2, the length of the contact 1 is 5 to jQ mm.

As a high-resistance isoelectric adhesive, a carbon-dispersed adhesive with 104~
106Ω, am is used, and the thickness of the layer 9 is 0.5
~1,5yrLm, the width of brush-shaped contact 1 is 5
~l5mm, and the amount of interference between the contact 1 and the photoreceptor layer 7 is 0.5~lmm.

As the conductive fiber 1o, 5A-7 (trade name: carbon-dispersed acrylic fiber, resistivity 10'Ω, cm) is used, and this and the insulating fiber 11? They are blended at a ratio of 2:8, the number of fibers is 100,000 to 200,000 per square inch, the thickness of each fiber is 3 to 10 deniers, and the voltage of the bias power source 5 is approximately 1300. It is.

When the brush charging device comes into contact with the small perforated portion of the photoreceptor δ, spark emission 1iC begins to occur between the conductive fibers 10 and the conductive layer 6.

At this time, the energy source for increasing the spark discharge is the charge accumulated in the portion of the photoreceptor 8 that is in contact with the bias power supply 5 and the brush-like contact 1.

However, if a larger current is to flow through the bias power supply 5, it will be limited by the resistance component of the high-resistance conductive adhesive FJ9, so a large current will not flow through the conductive fiber 1o, and spark discharge will not become large, and the bias The voltage of the power source 5 hardly drops due to spark discharge.

Further, the path through which the charges accumulated in the contact portion of the brush-like contact on the photoreceptor 8 flows to the spark generation location (small hole) is as follows: conductive fiber 1o → high resistance conductive adhesive r:!
I9 → The conductive fiber 1o that has started to generate sparks,
Regarding each of the fibers that make up the brush-like contact, the resistance component of the high-resistance conductive adhesive n9 prevents a large current from flowing from the former path, and the latter path #: t has insulating fiber 11. Therefore, since almost no current flows, the amount of the electric charge flowing into the spark generating tube is significantly reduced, and together with the fact that the current flowing is smaller than that of the bias power supply 5 mentioned above, the spark discharge occurs at a very small stage. It doesn't get bigger.

Therefore, a small hole (0,277177
Even if the photoreceptor 8 is charged, the spark discharge will be extremely low.
Since it is small and the voltage drop of the bias power supply 5 is small, the defects in the image are so inconspicuous that they are difficult to detect, and other parts can be charged normally and a normal image copy can be obtained, and spark discharges are repeated. Also, holes and spark discharges do not become large, and image defects do not become large.

In the above embodiment, the base 4 and the base fabric 2 are bonded together using the high-resistance conductive adhesive layer 9, but a high-resistance layer may be interposed between the conductive adhesive layers. That is, the contactor 1 may be provided on the base 4 via a high-resistance conductive layer.

Effects of the Invention Since the current flowing to the spark generation point can be restricted to reduce the drop in the voltage applied to the base 4, the drop in the charging voltage of the portion of the photoreceptor layer 7 that is in contact with the brush-like contactor 1 is reduced. death,
Normal charging can be performed and copies with normal image quality can be obtained, and there is no spark discharge or enlargement of holes, so that defective parts do not become large.

[Brief explanation of the drawing]

FIG. M1 and FIG. 2 show an embodiment of the present invention, FIG. 1 is a front view of a brush charging device, FIG. 2 is a perspective view of a contact, and FIG. 3 is a front view of a conventional example. 1 is a contact, 4 is a base, 19 is a conductive fiber, and 11 is an insulating fiber.

Claims (1)

[Claims] A brush charging device characterized in that a contactor 1 made of a blend of conductive fibers 10 and insulating fibers 11 is provided in the shape of a brush on a conductive base 4 via a high-resistance conductor layer.