Method of screen printing stencil production
AssigneeAutotype International Limited
InventorsJohn W. Jones, David Joseph Foster
Life of this patent
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Abstract
A coated film product comprises a support base, a stencil-forming layer and an intermediate release layer. The stencil-forming layer is a blend of two grades of polyvinyl alcohol having different degrees of hydrolysis. The stencil-forming layer is imaged by dropwise application (for example using an ink-jet printer or plotter) of a cross-linking agent which hardens the stencil-forming layer to resist washing out with water. The hardened areas remaining after washing out are however sufficiently tacky for the washed-out film to adhere to the screen mesh by application of pressure and, after removal of the support base, form the stencil layer of a screen-printing screen.
Claims64
A method of producing a screen-printing stencil comprising a foraminous screen having thereon a stencil layer which is interrupted to form open areas and blocked areas for respectively passage and blocking of a printing medium through the screen and onto a printing substrate, the method comprising the steps of:
- (a) providing a receptor element comprising a continuous support base and a stencil-forming layer which is capable of reacting with a chemical agent applied thereto, the chemical agent comprising at least one active component which reacts with the stencil-forming layer upon said application to produce areas of lower solubility where application takes place and to leave higher solubility areas elsewhere, the areas of lower solubility being sufficiently adherent for attachment of the receptor element to the foraminous screen after washing away of the areas of higher solubility from the receptor element;
- (b) applying the said chemical agent imagewise to the stencil-forming layer in areas corresponding to the blocked areas of the stencil layer in order to produce by the said reaction between the said at least one active component of the chemical agent and the stencil forming layer the said areas of lower solubility where the said reaction takes place and to leave the said areas of higher solubility where no said reaction takes place;
- (c) washing away the stencil-forming layer from the continuous support base in the higher solubility areas to produce a washed-out stencil;
- (d) attaching the receptor element comprising the continuous support base and the washed-out stencil to the foraminous screen by bringing the washed-out stencil-forming layer of the receptor element into contact with the foraminous screen, whereby the receptor element becomes attached to the foraminous screen by the adherency thereto of the lower-solubility areas of the stencil-forming layer;
- and
- (e) removing the support base of the receptor element in order to produce the screen-printing stencil.
Dependencies are inferred from the claim text.