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. 20, 1993
Filed:
Aug. 19, 1992
John A Thompson, Boise, ID (US);
Kenneth E Heath, Boise, ID (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A thermo-electric image transfer system (50) for transferring a toned image directly to a paper or transparency medium in the absence of a liquid toner carrier. The medium is fed over a pre-heating platen (52) which drives excess moisture out of the medium. The medium is fed into a nip between first and second transfer rollers (64, 62). The first transfer roller (64) is heated so as to heat the backside of the medium, and includes a thermally and electrically conductive elastomeric layer (64A). A guide element (66) guides the medium out of the nip between the transfer rollers, and into another nip between the first transfer roller (64) and the photoconductor drum (68), with pneumatic cylinders maintaining pressure between the roller and drum. An electrostatic bias voltage is applied to the first roller (64) of a polarity opposite to that of the toner defining the image on the drum (68), to provide an electrostatic attraction of toner to the medium. The heat, pressure and electrostatic fields causes a toner image to be transferred to the medium from the drum (68). The medium is allowed to remain against the drum (68) to allow for cooling and adhesion to the medium, and thereafter is detached from the drum, with the image separating at the toner/photoconductor interface.