The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 30, 1991
Filed:
Oct. 02, 1989
Paul L Nielsen, Rochester, NY (US);
John C Wilson, Rochester, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
The invention provides rolls, belts and other biasable members having at least one layer or coating of an elastomeric resilient crosslinked polyurethane formed by reacting (a) a polyisocyanate prepolymer comprising the reaction product of an aliphatic polyisocyanate and a polyether polyol, specifically a polyalkylene glycol in which the alkylene group contains 2 to 3 carbon atoms, and (b) a hardening mixture comprising a polyether polyol of (a) and, as a conductivity control agent, from 0.01 to 3.0 weight percent based on the total weight of (b) of a complex of an oligoethylene glycol selected from the group consisting of di-, tri- and tetraethylene glycol with an ionizable alkali metal salt selected from the group consisting of sodium iodide, lithium iodide and sodium thiocyanate. The resistivity of the elastomeric resilient polyurethane coating on the biasable member is controlled or adjusted to within a desired level of resistivity due to the inclusion of the conductivity control agent in the crosslinked polyurethane elastomer. Additionally, the inclusion of the conductivity control agent in the crosslinked polyurethane elastomer reduces the sensitivity of the resistivity of the polyurethane coating on the biasable member to changes in relative humidity. Further, since the conductivity control agent is copolymerized with the polyisocyanate prepolymers and polyols used to make the elastomeric polyurethane coatings of the biasable members of the invention, the conductivity control agent is bonded covalently to the backbone and/or the crosslinking portion of the polyurethane elastomer where it forms a permanently fixed part of the crosslinked polymer and will not migrate therefrom resulting in a continuous change in the resistivity of the polyurethane coating over time and possible adverse affects on materials that may come into contact with the migrating agent. The utility of such biasable members is in the transfer of toner images from a photoconductor to a final support sheet where the member, for example, a bias transfer roll, electrically cooperates with a photoconductor to establish a directional force field therebetween.