JPH085480Y2 - Intermediate transfer conveyor belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention has a charging performance that does not scatter toner from a transfer intermediate that is a primary transfer of a toner image on an electrophotographic photoreceptor, and The present invention relates to an intermediate transfer conveyance belt having improved releasability from a transferred material.

<Prior Art> As an image forming means using an electrophotographic method, as shown in FIG. 2, a toner image on an electrophotographic photosensitive member 100 is primarily transferred onto a transfer intermediate 101, and then transferred onto an object 102 to be transferred. There is a second transfer. As the transfer intermediate 101, there is known an intermediate transfer conveyance belt in which a synthetic rubber material such as fluorine rubber or silicon rubber is used, and at least the toner image carrying surface is made conductive. By using this intermediate transfer conveyance belt, several toner images can be superposed on the intermediate transfer conveyance belt and then transferred onto the transfer target object 102, which can be repeatedly used when forming a full-color image or a composite image by trimming or masking. There is an advantage that it is not necessary to send the transcript.

<Problems to be solved by the invention> However, the conventional intermediate transfer conveyance belt is characterized in that the material thereof is made of synthetic rubber and at least the toner image carrying surface is formed to be conductive. It has the required characteristics of the belt, which is the charging performance to the extent that the toner from the transfer intermediate that transfers the toner image on the electrophotographic photoconductor temporarily and does not scatter, and improves the releasability of the transferred material. Since it has not been recognized that a suitable charging performance is imparted to such a degree, there is often a problem that the surface resistance and the electrostatic capacitance are small and the toner image cannot be secondary-transferred when the secondary transfer is performed. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an intermediate transfer conveyance belt having good transferability of a toner image even in secondary transfer.

<Means for Solving the Problems> The structure of the present invention for achieving the above-mentioned object is such that a coating layer of fluororesin is formed on one surface and 0.1 mm is formed on the other surface.
An intermediate transfer conveyor belt for electrophotographic copying apparatus having a thickness of 0.4 to 1.2 mm formed integrally with a core material layer of the following wound or knitted woven fabric, wherein the belt has 100 parts by weight of ester polyurethane rubber. It is molded from a composition containing 20 to 40 parts by weight of carbon powder and has a volume resistance of 10 ⁸
〜10 ¹² Ω ・ cm, surface resistance 10 ⁸ 〜 10 ¹³ Ω, capacitance 450
It features an intermediate transfer conveyor belt having a pF or more and a dielectric constant of 10 or more.

 The configuration of the present invention will be described below.

The intermediate transfer conveyor belt of the present invention is used as a transfer intermediate of an image forming means using a secondary transfer method as in the conventional case, and is wound around a pulley as shown in FIG. The carbon powder 12 is mixed with the body 11.

As the carbon powder, for example, "Asahi # 70" manufactured by Asahi Carbon Co., Ltd. or "Seast SO" manufactured by Tokai Carbon Co., Ltd.
Are preferably used.

Polyurethane rubber, particularly ester polyurethane rubber, is preferably used as the material for the intermediate transfer / conveying belt, and the thickness thereof is 0.4 mm to 1.2 mm.

The thickness l is defined here as 0.4 to 1.2 mm because the above characteristics are exhibited particularly suitably as the intermediate transfer conveyance belt when the thickness l is in this range.

The carbon powder compounded in the rubber material of this intermediate transfer conveyor belt usually has a particle size of about 30 to 80 μm.
20 to 40 parts by weight is added to 100 parts by weight. This is 20
If the amount is less than parts by weight, the volume resistance and the surface resistance will exceed the above specifications, and the capacitance and the dielectric constant will tend to be less than the above specifications.If the amount exceeds 40 parts by weight, the volume resistance and the surface resistance will decrease. This is because it tends to fall below the above regulations.

Further, in the present invention, as shown in FIG. 1 (b), a core material 14 of wound or woven cloth is integrally provided on the lower surface of the rubber body 11 containing the carbon powder 12.

Examples of the core material 14 of the wound or knitted fabric provided integrally with the rubber body 11 include cotton thread, polyester thread, aromatic polyamide thread, glass fiber, carbon fiber and the like, and the Young's modulus in tension is 200 kg / It is preferable to use one having a size of mm ² or more. This core material may be provided so as to be embedded in the vicinity of the contact surface of the rubber body on the pulley side, in addition to the case where it is provided on the lower surface of the rubber body as described above.

The core material 14 preferably has a thickness of 0.1 mm or less except that it is integrally embedded. This is because if the thickness is 0.1 mm or more, fine irregularities may occur on the surface of the rubber body.

Further, in this intermediate transfer conveyance belt, a coating layer 13 of a fluororesin is provided on the outer surface of the rubber body to improve the separation from the transferred material.

<Embodiment> A preferred embodiment of the present invention will be described below.

As a rubber material, 30 parts by weight of carbon powder having a particle diameter of 60 μm was added to 100 parts by weight of ester polyurethane, and an intermediate transfer carrying belt was obtained in the following steps.

A molded body is obtained by subjecting the polyurethane rubber containing the above carbon powder to extrusion molding known per se.

A cotton thread is wound around the surface of the mold until the thickness becomes 0.1 mm, and the extrusion molded body is covered and fixed together with glue, and vulcanized and molded to be integrated.

Next, the surface is polished to form a 0.8 mm belt, and then a fluororesin emulsion is sprayed onto the surface to form a coating layer on the surface to obtain a transfer / transport belt.

When the obtained transfer and transport belt was attached to a copying machine and used for a long period of time, no abnormalities such as uneven transfer of images were observed.

<Effects of the Invention> As described above with reference to the embodiments, the intermediate transfer conveyance belt of the present invention is a mixture of ester polyurethane rubber with carbon powder, and the volume resistance, surface resistance, capacitance and dielectric constant are specified. The effects of improving the transferability at the time of the secondary transfer by using the above-mentioned ones and of not causing the transfer unevenness even when used for a long period of time.

[Brief description of drawings]

FIG. 1A is a perspective sectional view of a copying and conveying belt according to an embodiment of the present invention, and FIG. 1B is a partially enlarged view thereof.
The figure is a schematic view of the secondary transfer mechanism. In the drawings, 11 is a rubber body, 12 is carbon powder, 13 is a fluororesin coating layer, and 14 is a core material.

Claims (1)

[Scope of utility model registration request] 1. An electrophotographic copying machine having a thickness of 0.4 to 1.2 mm, wherein a fluororesin coating layer is formed on one side, and a wound or woven fabric core material layer of 0.1 mm or less is integrally formed on the other side. An intermediate transfer / conveyance belt for use in which 100 parts by weight of ester polyurethane rubber are mixed with carbon powder 20-4.
It is molded from a composition containing 0 parts by weight,
Moreover, the volume resistance is 10 ⁸ to 10 ¹² Ω ・ cm, and the surface resistance is 10 ⁸ to 10
An intermediate transfer conveyor belt having a resistance of ¹³ Ω, a capacitance of 450 pF or more, and a dielectric constant of 10 or more.