Developing roller apparatus for reproduction machines

DETAILED DESCRIPTION What is claimed is: 1.
A developing roller for use in the development of heat-sensitive copy sheets in a reproduction machine, said roller comprising: a hollow, thin-walled heat conducting cylinder rotatably mounted in the reproduction machine; a plurality of relatively small diameter heat pipes mounted along the inner wall of said cylinder between its ends; and a means for heating said cylinder and heat pipes located within the hollow interior of said cylinder.
2.
The roller of claim 1 wherein said heat pipes are embedded in said inner cylinder wall.




Description:
Background of the Invention There are several general types of machines for reproducing an image on a copy sheet.
The type of reproduction machine with which the subject invention is concerned is the class wherein the image on the copy sheet is developed by heat.
One well known type of such machine is that using the diazo process.
In this process, the copy sheet is coated with a material which includes diazo compounds.
When exposed to ultraviolet light, the diazo compounds decompose into a form in which they become colorless.
The portions of the sheet which are not exposed to ultraviolet light retain the diazo compound which, upon interaction with couplers also contained in the coating, produce when heated intense azoic dyes which are insensitive to light and, hence, are capable of forming permanent visible images on the copy sheet.
In such a process, a light-sensitive coating solution maybe prepared by dissolving diazo compounds together with coupling substances in water which has been weakly acidified as by means of citric, tartaric, or boric acids.
The coating solution is then applied upon a sheet of material, such as paper, after which the sheet is dried to remove the water component.
When such a sheet is exposed to the action of ultraviolet light through an image-bearing layer of material that is transparent to such light, the diazo compound in the coating will be destroyed except where screened by the opaque images of the original to be copied