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:
Oct. 17, 2000
Filed:
Dec. 17, 1998
John W May, Rochester, NY (US);
Dean R Smith, Rochester, NY (US);
David M Zacher, Rochester, NY (US);
Bonnie A Maye, Rochester, NY (US);
Dennis A Kenyon, Rochester, NY (US);
Martin J Pernesky, Rochester, NY (US);
Other;
Abstract
A particularly configured aperiodic grid for a grid-controlled AC corona charger for uniformly charging a dielectric member, of an electrostatographic reproduction apparatus, moving along a travel path in operative relation to the corona charger. The corona charger includes an insulating housing and an electrically biased grid, in which the grid transparency is larger than a nominal transparency at the upstream edge of the charger grid, transparency is nominal at the center of the grid, and transparency is smaller than nominal at the downstream edge of a charger grid. The invention, which has been demonstrated for negative primary charging, preferably uses a trapezoidal AC waveform having a DC offset for corona excitation, and may be practiced over a large range of process speeds. The invention is also practiced using trapezoidal waveforms having negative duty cycles in the range 50% (conventional AC) to 90% (negative DC). The range of the variation in grid transparency from the upstream grid edge to the downstream grid edge is far greater than in prior art commercial machines.