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:
Sep. 26, 1995
Filed:
Nov. 01, 1993
Fred W Schmidlin, Pittsford, NY (US);
Other;
Abstract
A direct electrostatic printing process which is insensitive to the polarity of the toner material is disclosed. The donor member of the printing apparatus includes alternate narrow and wide electrodes. The narrow electrodes are electrically pulsed to eject toner of one polarity in proximity with an array of electrically controlled apertures in a printhead, and unused toner are returned to the donor surface with low momentum to avoid dislodgment of other toner from the donor on impact. Toner ejection is accomplished with a three segment voltage pulse, including an impulse segment to detach toner of one polarity from the donor and accelerate the toner particles toward a printhead, a zero voltage segment during which the ejected toner drifts in the presence of electric fields produced by voltages applied to the printhead and toner receiving member, and a final low voltage segment of the same polarity as the first impulse segment to decelerate toner returning to the donor to a low landing speed and thereby avoid dislodgement of other toner from the donor. The donor structure and ejector pulse renders aperture type direct printing stable for long periods of time without frequent cleaning of the printhead.