Method and apparatus for forming dye sublimation images in solid plastic
Method for forming a dye sublimation image in a substrate, particularly a plastic substrate, and apparatus to perform the method. According to the method taught by the present invention, a substrate is disposed on a perforated platen and a dye carrier having an image formed thereon of a dye sublimation ink is disposed on the substrate such that the image is in contact with the substrate. The substrate, dye carrier and at least a portion of the perforated platen are then covered with a flexible membrane. A clamping pressure is then applied to the substrate and the dye carrier through the membrane. Once the clamping pressure is attained, the substrate and dye carrier are first heated, then cooled. The invention disclosed herein further teaches a number of novel apparatus to effect the method, resulting in significantly superior dye sublimation imaging than heretofore attainable in rigid plastic sheets.
1. A method for forming a dye sublimation image in a thermoforming plastic substrate with a dye carrier having an image formed thereon of a sublimatic dyestuff, the method comprising:
placing the image of the dye carrier against a first surface of the thermoforming plastic substrate to form a substrate-dye carrier stack;
heating the substrate-dye carrier stack to a sublimation temperature;
cooling the substrate-dye carrier stack; and
providing a clamping pressure against the first surface of the thermoforming plastic substrate during the heating and the cooling and therebetween; wherein the clamping pressure is provided by:
placing the thermoforming plastic substrate on a platen;
covering the dye carrier, thermoforming plastic substrate, and at least a portion of the platen with a membrane; and
applying a pressure differential across the membrane, wherein the clamping pressure limits warping of the substrate during the heating, cooling, and therebetween.
2. The method, as recited in claim 1 , wherein the clamping pressure provides a pressure over an entire surface of the dye carrier.
3. The method, as recited in claim 1 , wherein the clamping pressure provides a pressure of at least 14 pounds per square inch.
4. The method, as recited in claim 1 , wherein the cooling cools the substrate to a temperature which causes the substrate to be substantially rigid.
5. The method, as recited in claim 1 , wherein the heating heats to a temperature of between 200° F.-600° F.
6. The method, as recited in claim 1 , wherein the clamping pressure provides a pressure of between 0.25 atmospheres to 20 atmospheres.
7. The method, as recited in claim 1 , wherein the clamping pressure is provided by a gas pressure differential to provide the continuous pressure.
8. The method, as recited, in claim 1 , wherein the heating is to a temperature and for a period of time requisite to sublimate the image into the substrate.
9. The method, as recited in claim 1 , wherein the platen is a perforated platen with perforations forming a plurality of vacuum orifices, wherein the applying a differential pressure comprises applying a vacuum through the plurality of vacuum orifices.