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US 4,304,842 AGranted
Process and apparatus for the manufacture of a relief printing form and the printing form thus manufactured
AssigneeAkzo N.V.
InventorJohannes C. Schoute
Life of this patent
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AssigneeAkzo N.V.
InventorJohannes C. Schoute
Estimating the term…
A process is provided for making a relief printing form which is at least partially cylindrical from a liquid photopolymerizable molding material. In accordance with the process, a molding material is spread over the internal surface of the cylindrical wall by centrifugal force and hardened in the desired places with ultraviolet light to form an image corresponding to a printing design. The nonhardened portions of the molding material are then removed. The cylindrical wall is a transparent cylindrical tube. An exchangeable image-bearing film is placed on the inside of the tube. Photopolymerizing radiation of the printing form material is effected during rotation of the transparent cylindrial tube. An exchangeable image-bearing film is placed on the inside of the tube. Photopolymerizing radiation of the printing form material is effected during rotation of the transparent cylinder by means of one or more radiation sources distributed around the circumference of the transparent cylinder. The rays act on the molding material via the wall of the transparent cylinder and the image-bearing film. The radiation for hardening the printing form takes place in a continuous operation following the application of the molding material to the cylindrical wall by centrifugal force.
In a process for the manufacture of a relief printing form which is at least partially cylindrical from a liquid photopolymerizable molding material which comprises spreading a molding material over the internal surface of the cylindrical wall by centrifugal force, hardening the resulting layer of molding material in selected places by means of ultraviolet rays via an image corresponding to a printing design and removing at least partially remaining nonhardened molding material, the improvement wherein the molding material is spread on a wall of a transparent cylindrical tube to form an exchangeable image-bearing film, and photopolymerization of the printing form material is effected with radiation while rotating the transparent cylinder, said radiation being effected by means of one or more radiation sources distributed around the circumference of the transparent cylinder, the rays of which act on the molding material via the wall of the transparent cylinder and the image-bearing film whereby the radiation for hardening the printing form takes place in a continuous operation following the application of the molding material to the cylindrical wall by centrifugal force.
In a method for making a relief printing form which comprises spreading a liquid photopolymerizable molding material over an internal cylindrical surface of a transparent walled cylindrical tube by centrifugal force in a predetermined design, hardening only portions of the resulting film by exposure to ultraviiolet light and removing at least a portion of the remaining nonhardened molding material to form a printing design, the steps of photopolymerizing the said resulting film where it is to be hardened by exposing the film to said untraviolet light continuously while rotating the said tube, said ultraviolet light striking said film through the transparent wall of said tube.
A process for making a substantially cylindrical relief printing form which comprises spreading by centrifugal force an ultraviolet light curable resinous material over the internal surface of an axially rotatable cylinder having a wall which is transparent to ultraviolet light, passing ultraviolet light through areas of said wall corresponding to a desired printing design to selectively harden areas of the resinous material while rotating the cylinder, and removing resinous material which is not hardened to form a printing pattern, removing the resulting pattern from the wall of the cylinder, and assembling the pattern with a support therefor.
Dependencies are inferred from the claim text.