Printing with differential adhesion

Abstract

This invention relates to the printing of a substrate having a pre-printed “print pattern” with a “design layer” of ink where there is differential adhesion within and without the print pattern. The print pattern is receptive to an ink, and the design layer ink forms a durable image material with good bond to the print pattern, but the ink does not form a durable image material on the portions of the substrate outside the print pattern. The design layer ink is a UV-curable ink, and the print pattern may have a higher surface energy than the portions of the substrate outside the print pattern.

Description

This Application is based on Provisional Application No. 60/350,018 filed Jan. 23, 2002, the entire contents of which is hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates to the printing of a substrate having a pre-printed “print pattern” with a “design layer” of ink with differential adhesion within and without the print pattern.

BACKGROUND OF THE INVENTION

GB 2 118 096 (Hill and Yule), U.S. Re. Pat. No. 37,186 (Hill) reissued from U.S. Pat. No. 4,673,609 and U.S. Pat. No. 4,925,705 (Hill) describe methods of printing with exact registration, in which layers of cured ink are removed from areas of a substrate to leave exactly superimposed layers of ink on the remaining areas of the substrate. Methods referred to in these patents as the “direct” and “stencil” methods require an “ink fracture mechanism” to be formed around the desired “silhouette pattern” or “print pattern”, typically of dots or lines. UV-curing ink is not disclosed in these patents, and typical UV-curing screenprinting ink has been found to be unsuitable for these methods. That is because the “chemical cross-linking” which occurs upon UV-curing creates a “membrane strength” or tensile capability in the cured ink layer(s) which prevents ink fracture or which prevents a “clean” ink fracture along the desired boundary of each area of the print pattern. Thus, any resultant fracture is irregular and inaccurate, with ink ‘flaps’ projecting into areas outside the desired or intended print pattern.

U.S. Pat. No. 6,267,052 “Printing with Differential Receptivity” (Hill and Godden), discloses methods of printing with lack of registration and printing with exact registration, together with seven methods of exactly superimposing an image “design layer” onto a pre-printed “print pattern” which partially covers a substrate. One of those seven methods is Method 3, “Conventional Printed Ink or Digital Ink Jet Differential Adhesion Method.” According to Method 3, the ink adheres to the print pattern to form a durable image material but does not form a durable image material on the unprinted portions of the substrate. That method can be used for a variety of purposes, including manufacturing one-way vision panels according to U.S. Re. 37,186 or other products in which areas of the substrate are required to be printed with exactly superimposed layers of ink. U.S. Pat. No. 6,267,052 discloses alternative inks that are suitable for forming a “design layer” by means of Method 3, including water-based inks, catalytic inks, and solvent-based inks. UV-curable inks are not disclosed in that patent, and UV-curable inks are believed never to have been disclosed or used in connection with Method 3. U.S. Pat. No. 6,267,052 also discloses the use of self-adhesive vinyl stripes to form a “print pattern”, and applying an “application tape” or “overlaminate” to imaged vinyl stripes to enable their application to a window.

U.S. Pat. No. 6,210,776 discloses what is referred to as the “Through Combination” method of managing the normal lack of registration in the printing of superimposed layers which can arise when making panels. UV-curing screen ink has been used to make such panels according to Method 3 under the trademark Overlap Registration System™, the panels being sold under the trademark Contra Vision SCREENLINE™, both trademarks being owned by Contra Vision Ltd, a UK company. The Through Combination method does not utilize differential receptivity or differential adhesion or removal of unwanted ink.

SUMMARY OF THE INVENTION

According to the present invention, a method is disclosed for making a printed panel having a design printed thereon, with the design including a durable image material design layer. The method includes 1) forming a print pattern onto a substantially imperforate substrate to form a patterned substrate, with the print pattern subdividing the substrate into a plurality of discrete printed areas and/or a plurality of discrete non-printed areas; and 2) presenting a design-generating medium to the patterned substrate to form an imaged substrate without regard to whether the design-generating medium is being presented to the areas of the print pattern or to the areas outside the print pattern. The design-generating medium causes the durable image material design layer to be formed only within the print pattern but not outside the print pattern, and the design-generating medium causes either (i) no image material to be formed on the areas outside the print pattern or (ii) only non-durable image material to be formed on the areas outside the print pattern. The durable image material design layer is formed from UV-curable ink. Non-durable image material is defined as material which can be substantially removed by water-jetting at a pressure not greater than 2,000 lb/in² (140 kg/cm²) with a water flow rate of not greater than 15 liters/minute, and any durable image material having good adhesion to the substrate will remain substantially not removed by water-jetting at a pressure not greater than 2,000 lb/in² (140 kg/cm²) with a water flow rate of not greater than 15 liters/minute.

In all applications of the method of the invention, only part of the substrate, termed the “print pattern” is durably imaged. The “print pattern” includes a plurality of discrete printed areas and/or interconnected areas surrounding a plurality of discrete non-printed areas. Examples of print patterns include a pattern of dots or lines or a grid, net or filigree pattern. The print pattern includes a single layer of marking material or a plurality of layers of marking material. In a preferred embodiment, the print pattern includes layers of ink printed in substantially exact registration. The print pattern ink is typically solvent-based ink that is applied, for example, according to U.S. Re. No. 37,186 or U.S. Pat. No. 4,925,705, UV-cured ink; epoxy-based ink; or water-based ink. The print pattern may include varied, sequential layers, with the first layer having good adhesion to the substrate, the subsequent layer or layers having good adhesion to the previous layer and the top layer providing good adhesion to the design layer. If the print pattern is desired to be receptive to those inks or other imaging materials that are designed and formulated to be applied to polyvinyl chloride materials, the final layer of the print pattern (if several layers are used) typically is an ink that has a surface with vinyl-like properties, such as Coates Vynalam™, an ink made by Coates Screen plc, a UK company. The print pattern can be of any color or combination of colors, or it may be a water-clear transparent layer or layers or a translucent layer or layers.

As used herein, the term “design layer” refers to a layer of material that is applied to a previously formed “print pattern” by presenting an “addressed design” to the substrate using a “design-generating medium.” The design layer can be a single layer of a single material, such as a single layer of ink, or it can be a multi-color printing process layer, in which individual color deposits (typically of black, cyan, magenta and yellow) are typically discontinuous within the design layer and any “printed portion” within the design layer.

In a preferred application of the invention, a UV-curable ink design layer is digitally printed onto a substrate having a pre-printed print pattern on it. Any UV-curable ink which does not form a durable image material is removed, for example by suction; by air-jetting; by jetting with a liquid (for example, water, but preferably a non-aqueous liquid); or by the application and removal of a layer which adheres to the surface of any ink or other marking material applied to the substrate but which only removes any non-durable image material, thus leaving the durable image material on the substrate within the desired print pattern. 70 60 in the gaps 6 between the print pattern 5. When the sign is no longer required on window 60, the assembly shown in FIG. 10G can be removed in one piece from the window by virtue of the bond provided by adhesive 52 being greater than the bond to the window, provided by adhesive 16.

The embodiments described above are intended to be illustrative of the invention. Modifications to and departures from these embodiments are deemed to be within the scope of the following claims.

Claims

1. A method of making a printed panel comprising a substantially imperforate substrate and having a design printed thereon, the design comprising a durable image material design layer adhered to a print pattern which subdivides the substantially imperforate substrate into a plurality of discrete printed areas and/or a plurality of discrete non-printed areas, the method comprising: forming said print pattern on said substantially imperforate substrate to form a patterned substrate; and presenting a design-generating medium comprising UV-curable ink to the patterned substrate, said presenting comprising digitally inkjet printing said UV-curable ink to form an imaged substrate without regard to whether the design-generating medium is being presented to areas of the print pattern or to areas outside the print pattern; and UV-curing the UV-curable ink into a UV-cured ink; wherein the design-generating medium and UV-curing causes the durable image material design layer to be formed only within the print pattern but and not outside the print pattern, and wherein the design-generating medium causes either (i) no image material to be formed on the areas outside the print pattern, or (ii) only non-durable image material to be formed on the areas outside the print pattern, which non-durable image material does not have good adhesion to the substantially imperforate substrate; wherein, after said UV-curing, the durable image material design layer comprises UV-cured ink; and wherein non-durable image material is defined as material which can be substantially removed by water-jetting at a pressure of 2,000 lb/in² (140 kg/cm²) with a water flow rate of 15 liters/minute and any durable image material with good adhesion to the substrate will remain substantially not removed by water-jetting at a pressure of 2,000 lb/in² (140 kg/cm²) with a water flow rate of 15 liters/minute, wherein said substantially imperforate substrate is coated with a UV-curable material, said UV-curable material is partially cured, image material is applied to form said print pattern, and said image material is partially cured and said UV-curable material is fully cured.

2. A method as claimed in claim 1, wherein said print pattern comprises a material which is first applied to the substantially imperforate substrate and which has a higher surface energy than the surface energy of the substantially imperforate substrate outside the print pattern.

3. A method as claimed in claim 1, wherein said print pattern comprises a material applied to the substrate and having good adhesion to the substrate and wherein any material outside the print pattern does not have good adhesion to the substrate.

4. A method as claimed in claim 1, wherein said UV-curable ink is digitally printed by an inkjet printer.

5. A method as claimed in claim 4 1, wherein:

said presenting comprises digitally inkjet printing said UV-curable ink using an inkjet printer; and

said inkjet printer utilizes piezoelectric inkjet nozzles.

6. A method as claimed in claim 4 1, wherein a time delay is provide provided between contact of said UV-curable ink with said patterned substrate and the application of UV-curing regime to cure said UV-curable ink.

7. A method as claimed in claim 4 1, wherein said ink is preheated to a temperature not less than 25° C.

8. A method as claimed in claim 7, wherein said ink is cooled before or upon contact with said substantially imperforate substrate.

9. A method as claimed in claim 1, wherein said substantially imperforate substrate is pre-treated prior to the application of said print pattern to increase its surface energy.

10. A method as claimed in claim 9, wherein said wherein said substantially imperforate substrate is pre-treated using a corona surface treatment comprising an electrical discharge.

11. A method as claimed in claim 10, wherein said corona surface treatment raises the surface energy of said substantially imperforate substrate to above 40 dynes/cm², and wherein said substantially imperforate substrate is printed with said print pattern, and wherein said surface energy subsequently dissipates with time to less than 35 dynes/cm² such that said UV-curable ink adheres well to said print pattern but said UV-curable ink does not adhere well to said substrate.

12. A method as claimed in claim 1, wherein said non-durable image material is removed by jetting with a substantially non-aqueous fluid.

13. A method as claimed in claim 12, wherein said fluid comprises air.

14. A method as claimed in claim 12, wherein said fluid comprises air with a particulate abrading medium an abrading medium comprising air and a particulate material.

15. A method as claimed in claim 12, wherein said fluid comprises solvent-based liquid.

16. A method as claimed in claim 1, wherein said non-durable marking image material is removed using means of adhesion.

17. A method as claimed in claim 16, wherein said means of adhesion comprises the application and removal of a self-adhesive film to said imaged substrate.

18. A method as claimed in claim 16, wherein said means of adhesion comprises a liquid layer which cures to adhere to the surface of the image material to form an adhered layer, which adhered layer is subsequently removed together with said non-durable image material attached to said adhered layer.

19. A method as claimed in claim 1, wherein said substantially imperforate substrate is transparent.

20. A method as claimed in claim 1, wherein said print pattern comprises a white layer of image material.

21. A method as claimed in claim 1, wherein said print pattern comprises a black layer of image material superimposed with a white layer of image material.

22. A method as claimed in claim 1, wherein said print pattern comprises a clear material.

23. A method as claimed in claim 22, wherein said clear material is transparent.

24. A method as claimed in claim 1, wherein the design layer comprises a design color layer and wherein said design color layer does not extend over the whole of the print pattern.

25. A method as claimed in claim 1, wherein said substrate is coated with a UV-curable material, said UV-curable material is partially cured, image material is applied to form said print pattern, and said image material is partially cured and said UV-curable material is substantially fully cured.

26. A method as claimed in claim 1, wherein said substrate is coated with a coating having a surface energy less than 30 dynes/cm² and portions of said coating are removed by etching from the areas of the print pattern to reveal the substrate.

27. A method as claimed in claim 26, wherein said etching is chemical etching.

28. A method as claimed in claim 26, wherein said etching is by means of a laser.

29. A method as claimed in claim 1, wherein the non-durable image material is substantially removed from the areas of the patterned substrate outside the print pattern by the application of an abrading medium under pressure at a rate of less than 10 kg per minute.

30. A method as claimed in claim 1, wherein the non-durable image material is substantially removed from the areas of the patterned substrate outside the print pattern by the application of an abrading medium under pressure at a rate of less than 5 kg per minute.

31. A method as claimed in claim 1, wherein the non-durable image material is substantially removed from the areas of the patterned substrate outside the print pattern by the application of an abrading medium under pressure at a rate of less than 2 kg per minute.

32. A method as claimed in claim 1, wherein said print pattern is formed using self-adhesive vinyl stripes.

33. A method as claimed in claim 32, wherein said self-adhesive vinyl stripes are imaged with said design layer comprising UV-curable ink, and wherein an overlaminate is applied to said design layer by means of heat-activated adhesive.

34. A method as claimed in claim 33, wherein the self-adhesive vinyl stripes are applied to a window, and wherein the adhesion of the overlaminate to the design layer is greater than the adhesion of the self-adhesive vinyl stripes to the window.

35. A method of making a printed panel comprising a substantially imperforate substrate, a background color layer, and a design comprising a design layer, the method comprising:

forming said background color layer directly on the substrate, wherein the background color layer defines a print pattern that subdivides the substantially imperforate substrate into a plurality of discrete printed areas and/or a plurality of discrete non-printed areas, wherein forming said background color layer comprises digital inkjet printing UV-curable ink;

digital inkjet printing said design layer onto the print pattern after forming the background color layer, wherein printing said design layer comprises digital inkjet printing UV-curable ink; and

UV-curing the UV-curable ink of the design layer and the UV-curable ink of the background color layer.

36. A method as claimed in claim 35, wherein said substantially imperforate substrate is transparent.

37. A method as claimed in claim 35, wherein said forming of said background color layer comprises forming a black material layer of said UV-curable ink directly on the substrate and a white material layer superimposed on the black material layer.

38. A method as claimed in claim 35, wherein said UV-curable ink of the background color layer comprises white UV-curable ink.

39. A method as claimed in claim 35, wherein said UV-curable ink of the background color layer comprises a layer of black UV-curable ink and a layer of white UV-curable ink.

40. A method of making a printed panel comprising a substantially imperforate substrate, a print pattern, a background color layer, and a design comprising a design layer, the method comprising:

digital inkjet printing said print pattern comprising UV-curable ink directly onto the substrate, wherein the print pattern subdivides the substantially imperforate substrate into a plurality of discrete printed areas and/or a plurality of discrete non-printed areas;

digital inkjet printing said design layer over the print pattern after printing said print pattern to form said design layer on said print pattern, wherein the design layer comprises UV-curable ink;

digital inkjet printing said background color layer after printing said design layer to form said background color layer on said print pattern, wherein said background color layer comprises UV-curable ink; and

UV-curing the UV-curable ink of the print pattern, the design layer, and the background color layer.

41. A method as claimed in claim 40, wherein said substrate and said print pattern are transparent.

42. A method as claimed in claim 41, wherein said design layer is reverse printed such that it appears as a right-reading design when observed through said transparent substrate and said transparent print pattern.

43. A method as claimed in claim 40, wherein said design and background layers are not applied to said non-printed areas.

44. A method as claimed in claim 40, wherein one of said design layer or said background color layer are applied to both of said printed areas and non-printed areas and removed from said non-printed areas.

45. A method as claimed in claim 40, wherein said UV-curable ink of the background color layer comprises white UV-curable ink.

46. A method as claimed in claim 40, wherein said UV-curable ink of the background color layer comprises a layer of white UV-curable ink and a layer of black UV-curable ink.