Process of making flexible belts by pultrusion

Details Process of making flexible belts by pultrusion Process of making flexible belts by pultrusion

1999-12-15

2001-09-11

Tentoni, Leo B. (Department: 1732)

Plastic and nonmetallic article shaping or treating: processes

With printing or coating of workpiece

Coating or impregnating workpiece before molding or shaping...

C156S175000, C264S171240, C427S385500, C427S387000, C427S393500, C427S434600

Reexamination Certificate

active

06287498

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to flexible belts. More particularly it relates to flexible belts fabricated from fibers that are coated with one or more liquid elastomers.
BACKGROUND OF THE INVENTION
Electrophotographic printing is a well known and commonly used method of copying or printing original documents. Electrophotographic printing is performed by exposing a light image representation of a desired document onto a substantially uniformly charged photoreceptor. In response to that light image the photoreceptor discharges, creating an electrostatic latent image of the desired document on the photoreceptor's surface. Toner particles are then deposited onto the latent image to form a toner image. That toner image is then transferred from the photoreceptor onto a receiving substrate such as a sheet of paper. The transferred toner image is then fused to the receiving substrate. The surface of the photoreceptor is then cleaned of residual developing material and recharged in preparation for the production of another image.
Many electrophotographic printers use flexible belts. For example, exposure is often performed on flexible belt photoreceptors, transfer often involves the use of flexible transfer belts, and fusing is often performed using flexible fusing belts. Flexible belts are of two types, seamed or seamless. Seamed belts are fabricated by fastening two ends of a web material together, such as by sewing, wiring, stapling, or gluing. Seamless belts are typically manufactured using relatively complex processes that produce a continuous, endless layer. In general, seamless belts are usually much more expensive (5-7X) than comparable seamed belts. While seamed belts are relatively low in cost, the seam introduces a “bump” that can interfere with the electrical and mechanical operations of the belt. For example, if a seamed belt is a photoreceptor the seam can interfere with the exposure and toner deposition processes, resulting in a degraded final image. While it is possible to synchronize the printer's operation such that the seam area is not exposed, such synchronization adds to the printer's expense and complexity. Additionally, even with synchronization the mechanical problems related to the seam bump, such as excessive cleaner brush wear and mechanical vibrations, still exist. Therefore low cost seamless belts have significant advantages over seamed belts.
Electrophotographic printing belts, whether seamless or seamed, are usually comprised of multiple layers, with each layer introducing a useful property. For example, one layer might provide the majority of a belt's mechanical strength, another might introduce an imaging layer, and another might improve a belt's toner release properties, while yet another might improve thermal properties. Because multiple layers should be mutually compatible, and since such compatibility significantly limits that range of acceptable materials, manufacturing multiple layer electrophotographic printing belts is particularly challenging.
Therefore, given the difficulty of manufacturing seamless flexible belts and of manufacturing multiple layer flexible belts, new manufacturing processes for such flexible belts would be beneficial.
SUMMARY OF THE INVENTION
The principles of the present invention provide for a new method of manufacturing flexible belts. Flexible belts according to the principles of the present invention are formed from fibers that are soaked with a liquid elastomer using a modified pultrusion process. Those fibers are then fabricated to form a flexible belt. Beneficially, multiple layer flexible belts can be formed by selectively pultruding fibers through a first liquid elastomer and then through a second liquid elastomer.
If a flexible belt is being fabricated using fibers soaked in only one liquid elastomer, the fibers are first soaked with that elastomer. The elastomer-soaked fibers are then wound around a core. The wound core is then passed through a forming die that smoothes the elastomer-soaked fibers into the shape of a belt. The liquid elastomer is then cured and the resulting fiber-reinforced elastomer is removed from the core, producing a flexible belt.
If a multiple layer flexible belt is being fabricated a first layer is formed by soaking fibers in a first elastomer, winding those soaked fibers around a core, passing the wound core through a die to smooth the first elastomer-soaked fibers into the shape of a belt, and then curing the first liquid elastomer. After the first layer is formed, a second belt layer is placed over the first layer by first soaking fibers with a second elastomer, winding the second elastomer-soaked fibers around the first layer, passing the newly wound core through a die to smooth the belt fibers into the shape of a belt, and then curing the second liquid elastomer. If flexible belts having more layers are desired the foregoing process can be repeated. The final cured belt is then removed from the core. Beneficially the different liquid elastomers and fabrics along with the windings are tailored to achieve desirable belt properties such as low surface energy, low friction, and different conformabilities.


REFERENCES:
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patent: 4921557 (1990-05-01), Nakamura
patent: 5122417 (1992-06-01), Murakami et al.
patent: 5763125 (1998-06-01), Kawata
patent: 6106944 (2000-08-01), Heikkila et al.
patent: 6217964 (2001-04-01), Ndebi et al.
patent: 0 933 688 A2 (1999-08-01), None
Fibreforce, Replacing Metals Where It Matters: “The Pultrusion Process,” http://www.fibreforce.u-net.com/process.html (undated).
Fibreforce, Replacing Metals Where It Matters: “Pullwinding,” http://www.fibreforce.u-net.com/pullwind.html (undated).
Brochures by KaZak Composites Incorporated (undated).
Brochures by Polygon, “Living with Composites Technology” (undated).

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