NZ211971A

NZ211971A - Screen material for screen printing process made by electrolytic deposition on screen skeleton

Info

Publication number: NZ211971A
Application number: NZ211971A
Authority: NZ
Inventors: B Meuzelaar; H H Thuis
Original assignee: Stork Screens Bv
Priority date: 1984-05-07
Filing date: 1985-05-03
Publication date: 1987-05-29
Also published as: EP0164149A1; DK162382B; DK162382C; FI851777L; NL8401454A; FI851777A0; HK8090A; AU4205385A; CA1273599A; KR910007077B1; NO851792L; DK200685D0; MX166977B; IN165614B; PT80399A; NO165792B; KR850008132A; AU577851B2; BR8502149A; FI80403B

Abstract

A metal screen material comprising a metal screen, preferably a cylindrical screen, obtained by electrolytic deposition of a metal upon a screen skeleton and said screen material having a fineness of 250 to 1000 mesh. The screen opening is preferably defined by curved walls extending from the lower side of the screen opening to the upper side of the screen opening, the upper side of the screen opening having an area being larger than the lower side of the screen opening. The screen material is advantageously obtained by electrolytic deposition of a metal from an electrolytic bath upon a screen skeleton, the bath solution passing, at least during part of the electrolytic depositing time, through the openings in the screen skeleton connected as the cathode either in one direction or in the other reverse direction.

Description

<div class="application article clearfix" id="description"> 4 i / ® 2 © Q 21 197 1 i n Priority Date(s): . 771 Complete Specification Filed: ^.7 Cass: Publication Date: P.O. Journal, No: 2 $ MAY 1987 * % Patents form No.5 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION "SCREEN MATERIAL FOR PRINTING MATERIALS AND A METHOD FOR PRINTING MATERIALS USING SAID SCREEN MATERIAL" -I*/WE STORK SCREENS B.V. of 3, Raamstraat, 5S31 AT BOXMEER, The Netherlands, a Netherlands Body Corporate hereby declare the invention, for which-iywe pray that a patent may be granted to -Hve7us, and the method by which it is to be performed, to be particularly described in and by the following statement (followed by page I \.) 'tv 21.1971 ' m O - 1 ar SCREEN MATERIAL FOR PRINTING MATERIALS AND A METHOD FOR PRINTING MATERIALS USING SAID SCREEN MATERIAL BACKGROUND OF THE INVENTION This invention relates to a screen material having a fineness of at least 250 mesh as hereinafter defined and to a method of printing materials by means of this screen material. The term "mesh" used herein indicates the number of perforations per linear inch. For printings for which great detail fineness 5 and detail sharpness are desirable, screen material is known to be used in the form of a woven polyester gauze, said polyester gauze meeting the requirements of the fineness desired. Said known screen material presents the drawback 10 that at all times it has to be kept in store under tension mounted on frames. This requires large storage facilities, since a particular screen material which, for instance, is not being used for a long time, must nevertheless be stored in the pretensioned condition on a frame. 15 Another drawback is that, after providing the woven polyester gauze with holes, this gauze loses its dimensional stability, thus precluding the possibility , * 1' 0 of meeting the requirements applicable to a particular'' , >2 MAR 1937 J- 7 ! \? 211971 -2- printing. A further drawback is that the known screen material does not very well assume its original condition after having been used, so that when using such screen material the quality of the product being printed greatly decreases after a relatively short period of time. Still another drawback is that cross threads and weft threads of the woven polyester gauze are not anchored with each other, so that, when using a screen having screen openings of 400 mesh, it frequently occurs that a large number of openings have dimensions that differ from those desired. At last, there is an important drawback in that rounded threads are used for said screen materials, as a result of which the permeability to material passing through the screen openings strongly depends upon the thickness of the threads from which the polyester gauze is made. SUMMARY OF THE INVENTION It is now the object of the invention to provide a screen material which does not have said drawbacks and which is particularly well suited for printings to be performed with great detail sharpness and detail fineness, without the need for said screen material to be stored in a pretensioned condition on frames, thus making it possible to gain considerable savings in terms of storage space requirements. In addition, said screen material retains its dimensional stability and so provides for unlimited usability . This object is attained according to the invention b^^^ctrolytic deposition of at least one metal upon a/screen skeleton and has a fineness of 250 to lOOGmesh. When using such a screen, printed products are obtained which have excellent properties, also when 'i.M O-'K ' - 2 MAR 1987 ® 211971 - 3 - such screens are used over an extended period of time. It is quite surprising that it is possible to form metal screens having such a fineness. With particular advantage, the upper side of each of the screen perforations has a surface which is larger than the lower side of said screen perforation. Such type of screen presents excellent properties. Quite effectively, each screen perforation is defined by curved walls extending from the lower side of the 10 screen perforation to the upper side of the screen perforation as this provides excellent printing results. The screen material is very effectively obtained by electrolytic deposition of a metal upon a screen skeleton, a bath solution passing, at least during part 15 of the electrolytic depositing time, through the openings in the screen skeleton connected as the cathode. The forced movement of the bath solution through the openings in the screen skeleton results in screens being formed which have the aforesaid perforations and afford 20 the forming of a relatively rigid screen material that has a very great fineness as well. ^ With particular advantage, the screen material consists of a cylindrical screen, which type of screen has not been available so far with the fineness as 25. indicated. It goes without saying that this makes it ^ possible to produce in a very simple manner printings having the detail fineness and great detail sharpness as desired. , _ /' , o\ - 2 MAR 1987 y - 4 - 211971 10 o 15 20 25 The invention further relates to a method for printing materials while using a screen material having a fineness of at least 250 mesh, in said method being a screen used which comprises a metal screen obtained by electrolytic deposition of at least one metal upon a metal screen skeleton and having a fineness of 250 to 1000 mesh. In the method of the invention, printing effectively proceeds by using a screen obtained by electrolytic deposition, in which case at least during part of the electrolytic depositing time a bath solution passes through the openings in the skeleton screen. Other claims and many of the attendant advantages will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts without the figures. DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a screen material according to the invention; FIG. 2 is sectional view of a screen material according to the invention; and FIG. 3 is a view of a cylindrical screen material according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS ■ V Fig. 1 shows a screen material 1 consisting of a - c-.'v > 2 MAR5987..^etal screen i obtained by electrolytic deposition of at ■/fv > /J • / least one metal 2 upon a metal screen skeleton 3. The '30 screen has a fineness of 4 00 mesh, so that there are 400 openings 4 per 2,5 4 cm. (followed by page 4a) The screen skeleton has been produced by electrolytic deposition of metal onto a so-called mandrel. The mandrel is for instance a metal plate or heavy metal roller, the surface of which is provided with an array of electrically insulating dots. Metal is deposited onto the non-insulating areas of the mandrel to obtain a skeleton screen, the perforations of which correspond to the electrically insulating areas of the mandrel. The electrolytic bath as used for depositing said metal is a well-known electrolytic bath containing an organic compound comprising at least one unsaturated I a bond whxch does not belong to a =C-S=0 group such as r butyne diol. Fig. 2 shows the original skeleton shown by bars 3 and also shows more particularly the shape of a number of openings in the screen. As seen, the free upper side 5 of the screen opening has a larger area than the area of the screen opening on the lower side of the screen 6. (followed by page 5) ~ ' ' ' ' --■- *.r- -r.-.-'.g,'-^.. o © -5- 2 1 197 1 The screen opening is defined by the curved walls 8 of the lands bounding the screen opening 4. In addition, it is evident that the metal deposited by electrolytic deposition mainly extends on 5 one side of the screen skeleton. On the other side of the screen skeleton, only a small layer thickness 7 of the electrolytically deposited metal has precipitated. This is more particularly shown in fig. 2. The shape of the screen openings is obtained 10 by connecting a screen skeleton as the cathode and by having the electrolytic solution flow in the direction from the cathode to the anode or in the reverse direction. Preferably the direction of flow is from the cathode to the anode. 15 The screen according to the invention is particularly well adapted for printings for which hitherto woven polyester gauze has been used. The screen material according to the invention distinguishes itself very favorably from the woven poly-20 ester gauze by the dimensional stability of the screen material used, which results in the remaining screen material retaining its nondeformable character when forming the openings in the screen material, the screen permeability being no longer dependent upon the thickness of the lands 25 of the screen material by properly selecting the walls of the screen openings, and, finally, the size of the screen openings being ensured at all times, also after an extended period of use, this being in contradistinction to applications using woven polyester gauze. 30 Fig. 3 shows a cylindrical screen material according to the invention in the form of a cylindrical screen 1' said cylindrical screen material being particularly suitable for continuous printing. </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 211971 - 6 - WHAT WE CLAIM IS:

1. A screen material having a., fineness of at least 250 mesh, wherein the screen material consists of a metal screen obtained by electrolytic deposition of a metal upon a metal screen skeleton and has fineness comprised between 250 and 1000 mesh (as herein defined).

2. A screen material according to claim 1, wherein the upper side of each of the screen perforations has an area which is larger than the lower side of said screen perforation.

3. A screen material according to Claim 1 or 2, wherein each screen perforation is defined by curved walls extending from the lower side of said screen perforation to the upper side of the screen perforation.

4. A screen material according to one or several of the preceding claims, wherein the screen material is obtained by electrolytic deposition of a metal upon a screen skeleton, a bath solution passing, at least during part of the electrolytic depositing time, through the openings in the screen skeleton connected as the cathode.

5. A screen material according to claims 1-4, wherein the screen material comprises a cylindrical screen.

6. A method for printing substrates using a screen material having a fineness of at least 250 mesh, wherein a screen material is used consisting of a metal screen obtained by electrolytic deposition of at least one metal i !■: 7~ upon a metal screen skeleton and having a fineness <s>f\ 250 to 1000 mesh. '; - 2 MAR 337 ^ h - 7 - 211971 ©

7. A method according to claim 6, wherein the printing proceeds by using a screen obtained by electrolytic deposition, a bath solution passing through the openings in a screen skeleton during at least part of the electrolytic depositing time.

8. A method according to claim 6, wherein in the screen material the upper side of each of "the screen perforations has an area which is larger than the lower side of said screen perforation.

9. A method according to claim 6, wherein each screen perforation is defined by curved walls extending from the lower side of said screen perforation to the upper side of the screen perforation.

10. A method according to claim 6, wherein the screen material is a cylindrical screen.

11. A screen material having a fineness of at least 250 mesh arranged, constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.

12. A method for printing materials using a screen material having a fineness of at least 250 mesh as hereinbefore described with reference to any one of the embodiments shown in the accompanying drawings.

13. A printed material when printed by the method claimed in any one of claims 6-10 or 12. </div>