Electrotype for forming an image during a paper making process
The invention relates to improvements in methods of making security features, in particular electrotype security features. The electrotype for forming an image during a paper making process comprises a mesh to which is attached at least one image forming element.
1. An attachment to a face cloth of a cylinder mould for forming an image during a paper making process, the attachment comprising:
an electrotype having a mesh; and
at least one image forming element attached to the mesh.
2. The attachment as claimed in claim 1 , wherein the at least one image forming element is a plurality of unconnected image forming elements that are attached to the mesh.
3. The attachment as claimed in claim 1 , wherein the at least one image forming element comprises multiple layers.
4. The attachment as claimed in claim 1 , wherein the mesh has a line width in a range of 50-300 microns.
5. The attachment as claimed in claim 4 , wherein the line width is in a range 50-150 microns.
6. The attachment as claimed in claim 5 , wherein the line width is in a range 80-120 microns.
7. The attachment as claimed in claim 1 , wherein the mesh has a line spacing that is in a range of 100-500 microns.
8. The attachment as claimed in claim 7 , wherein the line spacing is in a range of 200-450 microns.
9. The attachment as claimed in claim 8 , wherein the line spacing is in a range of 250-400 microns.
10. The attachment as claimed in claim 1 , wherein the mesh has a thickness that is in a range of 20-150 microns.
11. The attachment as claimed in claim 10 , wherein the thickness is in a range of 50-100 microns.
12. The attachment as claimed in claim 11 , wherein the thickness is in a range of 60-90 microns.
13. A method of forming an electrotype comprising:
electroforming a first layer,
wherein the electrotype has a mesh and at least one image forming element attached to the mesh.
14. The method as claimed in claim 13 further comprising:
electroforming one or more additional layers on the first layer,
wherein the one or more additional layers comprise the at least one image forming elements without the mesh.
15. The method as claimed in claim 13 further comprising:
forming a first intermediate product by:
a) applying a layer of a conducting material to a support layer of a photopolymer film;
b) applying a layer of light sensitive photo resist to the layer of conducting material; and
c) applying a first mask comprising a mesh pattern and an image to the layer of resist;
forming a second intermediate product by:
d) exposing the first intermediate product to ultraviolet light; and
e) washing away the resist on the unexposed regions covered by the mask;
forming a third intermediate product by:
f) immersing the second intermediate product in an electroforming solution and depositing metal in the regions not covered by the resist.
16. The method as claimed in claim 15 further comprising:
repeating steps a) to f) one or more times having replaced the first mask of step c) with a second mask comprising the image without the mesh pattern, to form one or more additional layers on the first layer.
17. The method as claimed in claim 13 , wherein the first layer is deposited to a thickness in a range of 20-150 microns.
18. The method as claimed in claim 17 , wherein the first layer is deposited to a thickness in a range of 50-100 microns.
19. The method as claimed in claim 18 , wherein the first layer is deposited to a thickness in a range of 60-90 microns.
20. The method as claimed in claim 14 , wherein the one or more additional layers are deposited to a thickness in a range of 20-150 microns.
21. The method as claimed in claim 20 , wherein the one or more additional layers are deposited to a thickness in a range of 50-100 microns.
22. The method as claimed in claim 21 , wherein the one or more additional layers is deposited to a thickness in a range of 60-90 microns.
23. A method for manufacturing security paper comprising:
forming an electrotype mark by attaching an electrotype to a cylinder mould of a paper making machine,
wherein the electrotype has a mesh and at least one image forming element attached to the mesh.
24. The method as claimed in claim 23 further comprising:
forming an electrotype mark integrated with or adjacent to a conventional tonal watermark, the conventional tonal watermark being formed by embossings in a face cloth of the cylinder mould.
25. The method as claimed in claim 24 , wherein the watermark is an embossed multi-tonal watermark which comprises a flat non-embossed region for incorporation of the electrotype mark.