ELECTROPHOTOLUMINESCENT PRINTING PROCESS

• US 3,591,283 A
• Filed: 12/11/1968
• Issued: 07/06/1971
• Est. Priority Date: 12/11/1968
• Status: Expired due to Term

• Current Assignee: Joel M. Peisach
• Original Assignee: Joel M. Peisach
• Inventors: Peisach, Joel M.
• Application Number:
  US04/783,090
• Time in Patent Office: 937 Days
• US Class Current: 430/31
• CPC Class Codes: G03C 5/10 Reflex-printing; Photoprinting using fluorescent or phosphorescent means
• CPC Class Codes: G03G 17/00 Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces

Abstract

Systems employing electrophotoluminescent panels to obtain reproductions of originals, which systems include the steps of exciting a layer of an electrophotoluminescent material optically and with an applied electric field to cause said material to emit visible light; eliminating said optical excitation while maintaining said electric field, whereby said material continues to emit visible light; and placing the subject matter to be reproduced in juxtaposition with said layer of material for a predetermined period of time sufficient to permit a significant imagewise differential in decay of luminescence of said material to form in said layer a positive reproduction of said subject matter, and, optionally may further include the steps of removing the electric field for a short period of time and then reapplying it whereby to obtain an image reversal wherein the positive image on the panel is converted into a negative image; and systems employing the same to obtain a photographic reproduction on a photosensitive element.

Claims

2. A process as defined in claim 1 including the step of removing said subject matter from said layer.

3. A process as defined in claim 2 including the steps of removing said electric field for a short period of time and then reapplying it whereby to obtain an image reversal wherein said positive image on said panel is converted into a negative image.

4. A process as defined in claim 1 wherein said layer is exposed to ultraviolet light to cause said optical excitation.

5. A process as defined claim 1 including the steps of placing a photosensitive element in juxtaposition with said positive image for a time sufficient selectively to expose said photosensitive element to the imagewise emission of visible light from said material in said layer to form a developable image;

and thereafter developing said exposed element to provide a photographic reproduction of said subject matter.

6. A pRocess as defined in claim 5 wherein said photosensitive element includes a light-sensitive silver halide emulsion and said image is in silver.

7. A process as defined in claim 5 wherein said photographic image is a positive silver transfer image.

8. A process as defined in claim 3 including the steps of placing a photosensitive element in juxtaposition with said negative image for a time sufficient selectively to expose said photosensitive element to the imagewise emission of visible light from said material in said layer to form a developable image;

and thereafter developing said exposed element to provide a photographic reproduction of said subject matter.

9. A process as defined in claim 8 wherein said photosensitive element includes a light-sensitive silver halide emulsion and said image is in silver.

10. A process as defined in claim 8 wherein said photographic image is a positive silver transfer image.

11. A document copying process comprising the steps of providing an electrophotoluminescent panel and a source of ultraviolet light within a lighttight enclosure;

exciting said panel with said ultraviolet light and an applied electric field to cause said panel to glow;

shutting off said light;

placing a document to be copied in juxtaposition within said glowing panel to form a positive reproduction of said document on said panel;

placing a photosensitive element comprising a layer of a light-sensitive material in juxtaposition with said glowing panel to form a developable image on said layer;

advancing said exposed element to a developing station within said housing where said element is developed to provide a visible photographic image of said document; and

transporting said photographic image from said housing.

12. A process as defined in claim 11 wherein said light-sensitive material is a silver halide emulsion and said photographic image is a positive silver transfer image.