Super Soft, Very Low Compression Set, Material for Pressure Roller Application

Boris Avrushchenko, Wade Eichhorn

Compression set of a material is critical in fusing system applications and is therefore desired to be as low as possible, less than 10%. Greater compression set introduces issues of loss of nip over time and elevated temperatures, adversely affecting the performance. With very soft materials, such as foam rubbers, compression set can be much greater than 20%. Tensile strength and elongation of materials are values that indicate the strength of a material under pressure in the fusing nip. Accordingly, a material with higher tensile strength and elongation is preferred. The hardness or softness of a pressure roller is dependent upon the base rubber material. Critical physical parameters of the material chosen are the hardness, compression set, elongation, tensile strength and dynamic responses under temperature and pressure. This paper describes the evaluation of a silicone, non foam, rubber material with a softness of 15 Asker C and a compression set 8% or less, as applied to differing material thickness for pressure roller applications. Physical and dynamic properties of the super soft silicone rubber are compared against other rubber materials used in pressure roller applications

Nanoscale Testing of Specialized Polymers and Components used in Non Impact Printing

Wade Eichhorn, 7-SIGMA, Inc
Srikanth Vengasandra, Hysitron, Inc.

Nanoscale testing is a growing field applied across many disciplines, sciences and industries. Recently nanoscale testing of polymers used in the printing industry has been shown to supplement conventional testing of physical, dynamic and electrical properties. Nanoscale testing consists of a variety of nano testing methods that can be applied across the Non Impact Printing Industry, from material development and characterization to understanding functionality and failure modes of components. Nanoindentation, nanoscratch, nano dynamic mechanical analysis, nano modulus mapping, nano hardness, nano tensile strength and nano electrical conductivity can be measured and applied to analysis of polymer performance. This paper will describe nanoscale testing as applied to the characterization of polymers used in fusing and charge transfer applications, as well as nano testing of toner particles and fixation to print media. In addition, nanoscale testing of surface substrates, and adhesion to substrates is discussed as may be applied to ink jet technologies, thin films, and the non impact printing of electronics, biological and pharmaceutical materials.

Fuser Roller Core and Drive Collar Assembly Design for High Speed Printer

Sunil Chohan, Rich Duda, Wade Eichhorn

Very high speed electrophotographic printers often use a fusing system consisting of a fuser roller and associated drive mechanisms which employ a coupled drive hub assembly. The fuser roller typically includes a metal core onto or into which a mating drive hub and collar assembly are connected. Rotating at high rotational speed, and at high temperature, with extremely fast start/stop conditions, instabilities create issues between the contacting surfaces causing micro machining issues which eventually develop failure modes of the apparatus. Such is the case in the drive system employed in printers using a drive key and drive slot configuration. The thermal expansion of the aluminum core differs significantly from the thermal expansion of the steel drive hub causing loss of contact between the mating surfaces. Micro machining occurring between the steel drive key and the aluminum core slot, widens and weakens the drive slot causing eventual failure of the roller and drive hub, sometimes catastrophic. The design of the fuser core and the drive collar assembly has undergone development that takes into account the differing thermal expansion of the aluminum fuser core and the steel drive hub. The development has been furthered by a unique design which incorporates a self locking and self centering drive mechanism, along with a rubber interface design, again taking into account for the thermal expansion of aluminum and elimination of the drive key and slot, to address the failure mechanism of the previous designs. This mechanism absorbs the shock energy of the fast start – stop motion, dissipating the energy over the full surface diameter of the drive hub. This paper describes the design history, the associated failure modes, and the new and novel solution.

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