Abstract A relief printing plate is formed by providing a sheet of material that collapses within its own volume by application to a surface of the sheet of a particular type of radiant energy, such as infrared radiation, this surface of the sheet being covered by a film of material which reflects said radiation. A relief pattern is formed by vaporizing selected areas of the reflective film to uncover underlying areas of the sheet so that the unvaporized reflective film forms a reflective template of the pattern to be in relief, and thereafter applying the radiation to the surface to collapse the uncovered areas of the sheet and leave in relief the areas shielded by the reflective template. In a preferred form the reflective film is initially covered by a layer of material that absorbs sufficient heat from a beam of another type of radiant energy to vaporize the reflective film immediately underlying a spot on the absorbent layer heated by the beam. A paste-up or other graphic representation of material to be reproduced in relief is scanned to produce electric signals corresponding to contrasts in the scanned material and the signals are applied to modulate a beam of radiant energy, which is scanned over the absorbent layer in synchronism with the scanning of the graphic representation, so that the beam heats selected areas of the absorbent film to vaporize underlying areas of the reflective film in a pattern such that the unvaporized reflective film is in a pattern corresponding to the pattern to be reproduced in relief.
A method of forming a relief printing plate having a desired relief pattern thereon comprising the steps of: providing a sheet of thermoplastic material that is collapsible within its own volume by application of a first type of radiant energy to a surface thereof, said surface being covered by a film of material that reflects said first type of radiant energy; providing over the reflective film on said sheet a layer of a material that absorbs sufficient heat from a beam of a second type of radiant energy to vaporize the reflective film in the area immediately underlying a spot on the absorbent layer that is heated by said beam; preparing a graphic representation of material to be reproduced in relief on said sheet; scanning said representation with means for producing signals proportional to the contrasts in the representation; scanning said absorbent layer on the sheet with a beam of said second type of radiant energy that is adapted for heating areas of the absorbent layer to vaporize underlying areas of the reflective film and scanning said absorbent layer in a path corresponding to the path of the scanning of the representation and in synchronism therewith; applying said signals to modulate the intensity of said beam for heating areas of the absorbent layer to vaporize underlying areas of the reflective film in a pattern such that unvaporized reflective film is in a pattern corresponding to the pattern of relief to be formed; removing remaining areas of the absorbent film from the unvaporized reflective film prior to the application of said first type of radiant energy; and applying said first type of radiant energy to said surface until the uncovered areas of the sheet collapse below their original surface level leaving the areas that are covered by said reflective film in relief relative thereto.
Claim 2
Independent Claim
303 words
A method of forming a relief printing plate having a desired relief pattern thereon comprising the steps of: providing a sheet of thermoplastic material that is collapsible within its own volume by application of a first type of radiant energy to a surface thereof, said surface being covered by a film of material that reflects said first type of radiant energy; providing over the reflective film on said sheet a layer of a material that absorbs sufficient heat from a beam of a second type of radiant energy to vaporize the reflective film in the area immediately underlying a spot on the absorbent layer that is heated by said beam; preparing a graphic representation of material to be reproduced in relief on said sheet; scanning said representation with means for producing signals proportional to the contrasts in the representation; scanning said absorbent layer on the sheet with a beam of said second type of radiant energy that is adapted for heating areas of the absorbent layer to vaporize underlying areas of the reflective film and scanning said absorbent layer in a path corresponding to the path of the scanning of the representation and in synchronism therewith; applying said signals to modulate the intensity of said beam for heating areas of the absorbent layer to vaporize underlying areas of the reflective film in a pattern such that unvaporized reflective film is in a pattern corresponding to the pattern of relief to be formed; removing remaining areas of the absorbent film from the unvaporized reflective film prior to the application of said first type of radiant energy; and applying said first type of radiant energy to said surface until the uncovered areas of the sheet collapse below their original surface level leaving the areas that are covered by said reflective film in relief relative thereto.
Claim 3
Dependent Claim
46 words
The method of claim 1 which includes scanning said graphic representation with a neon helium laser, focussing the beam therefrom on said representation, detecting light from laser beam reflected from said representation, and converting said reflected light into signals proportional to the contrasts in said representation.
Claim 4
Dependent Claim
29 words
The method of claim 1 in which said beam of said second type of radiant energy applied for scanning said absorbent layer is the beam of a YAG laser.