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:
Feb. 08, 1977
Filed:
Jan. 20, 1975
Manfred R Kuehnle, Lexington, MA (US);
Coulter Information Systems, Inc., Bedford, MA (US);
Abstract
A system for impressing images on electrophotographic film provides apparatus for charging each film frame rapidly to a peak voltage determined by the prevailing light conditions of the image to be produced or recorded. After charging, means are provided for immediately exposing the frame to an image. In the preferred apparatus, means are provided for adjusting the time of exposure to a fixed period which is predetermined. Means are provided for applying toner to the exposed frame immediately after exposure in the presence of a bias field which propels the toner particles toward the film. Thereafter excess toner is removed from the film or leaves the frame and the remaining toner is fused to the surface of the film to form a permanent visible image on the film frame. An alternate form of the invention provides means for transferring the toned image to an acceptor member where it is fixed. The apparatus includes structure which enables the processes above described to be carried out along a line or in a rotary arrangement. Electronic and electrical circuitry are provided for accomplishing the various functions in proper sequence and timing. The apparatus is arranged to carry out the processes at points on the dark decay portion of the characteristic discharge curve for the particular film so that the resultant image has high resolution, optimum contrast and a substantially continuous gray scale. The quality is as good as if not better than photographic quality. The sensitivity of the film is controlled by the level to which it is charged and circuitry provided enables this to be automatically accomplished. The level in turn is chosen on the basis of the average light of the image or scene to be recorded and means are provided to accomplish this automatically or manually.