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:
Jun. 19, 1979
Filed:
Jan. 03, 1978
Kenneth W Gardiner, Menlo Park, CA (US);
Gerald L Pressman, San Jose, CA (US);
Electroprint, Inc., Sunnyvale, CA (US);
Abstract
An electrostatic latent image is impressed on a multilayer apertured screen to establish within the apertures electric fields that modulate the passage of charged particles through the screens so that the charged particles are distributed in correspondence with the image. After imaging the screen is operated to control the gray scale response thereof in order to optimize copy quality. The gray scale screen response is expanded by applying a bias voltage of at least two different values to the screen during the duplication interval. The response is limited by altering the latent image charge to provide a high density cutoff and by applying a bias voltage to establish a low density cutoff during the duplication interval. Copy quality is further improved by adjusting the integrated charged particle current to establish the desired degree of density in regions of the copy image corresponding to high density regions of the original image.