Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/14—Forme preparation for stencil-printing or silk-screen printing

Definitions

• the invention relates to a method for producing a flexible and dimensionally stable stencil support for screen printing. Dimensional stability is required above all against tensile loads.
• stencil carriers for screen printing have generally been woven from metal wire or plastic threads.
• fabrics have thickened areas at the "knots" where warp threads and weft threads overlap, which cannot be fully compensated even by calendering. It is therefore not possible to make completely flat or flat stencil carriers from fabrics.
• the changes in thickness are relatively significant.
• the present invention is therefore primarily intended for screens or fabrics in which the number of threads per centimeter length exceeds 10 threads, in particular is more than 20 threads.
• Template carriers are also known in which the disadvantages of fabrics are avoided.
• the "meshes" are holes with a hexagonal cross section, between which there are metal webs free of thickenings, for example made of nickel, in order to achieve the necessary stability. Since these webs are built up by, for example, galvanic deposition of individual nickel particles, the production of these stencil carriers is burdened with very high rejects and is therefore very complex and accordingly expensive.
• the object of the invention is to provide a stencil support for screen printing which does not have the disadvantages of the fabrics described and, moreover, can be produced without large reject rates with relatively little effort.
• a basic shape made of dimensionally stable material is provided on its surface with interconnected grooves, the inside width of which corresponds to the required "mesh width” and the maximum widths of which correspond to the required maximum web widths of the template carrier; the grooves of this basic shape are at least partially filled with a hardenable, liquid plastic;
• the plastic is hardened in the grooves and separated from the basic shape.
• the grooves preferably being in a metal surface, for example electrically, for.
• a metal surface for example electrically, for.
• the metal surface can be made of brass or copper, for example, which can optionally be surface-coated, for example chemically nickel-plated or hard-chrome-plated.
• a large number of stencil carriers are then produced with such a basic shape.
• the grooves are advantageously formed from intersecting straight lines, a preferred shape being obtained if the intersecting grooves are arranged perpendicular to one another.
• the plastic of two interconnected grooves connects to the Hardening that can be done thermally, chemically or by radiation without "thicker" knots.
• the separation of the plastic from the base mold can be facilitated by wetting the base mold with a release agent, for example a silicone oil, or by adding a release agent to the plastic.
• a release agent for example a silicone oil
• the stability of the stencil carrier against tensile loads can be increased if at least the grooves in one direction are provided with a reinforcement made of threads or wires, such as polyester, glass fibers or metal, which are as extensively invariable as possible in the longitudinal direction, the reinforcements advantageously having the grooves filled with Plastic can be inserted.
• V-shaped, oval or circular segment-shaped cross-sections which additionally widen conically and / or can also be asymmetrical, have proven to be advantageous. May continue to the intersecting grooves of a stencil carrier in the e "inen of the two directions from those of the other direction in pitch, ie in number per unit length, shape and depth different.
• a rotatable cylinder is used as the basic shape, in which the grooves run in the circumferential direction and along surface lines.
• Reinforced edge areas of the stencil carriers which are resistant to tensile load, can be produced in a simple manner if the edge areas of a basic shape have a step-shaped depression on at least two opposite sides into which a reinforcement can also be inserted if necessary.
• the thickness of the template carrier can be changed to a certain extent by varying the solids content in the liquid plastic.
• Fig. 1 shows schematically a flat plate that can be used as a basic shape for the production of individual stencil carriers of a certain size
• FIG. 2 shows, likewise schematically, a rotatable cylinder as the basic shape for the continuous production of template carriers
• Fig. 4 is a plan view of the surface of a base mold on an enlarged scale compared to Fig. 1 or 2;
• FIG. 5 is a cross section through the edge region of a template carrier with a reinforcement produced according to the new method
• a flat plate 1 in which at least the. surface to be provided with longitudinal and transverse grooves 2 and 3 is made of metal. In this surface are the grooves 2, 3, which are expedient in most cases run perpendicular to one another, incorporated using one of the methods mentioned, for example etched.
• the plate 1 is enclosed by a raised edge 4; In the groove-free end or edge areas 5 in the longitudinal direction a row of pins 6 are arranged. They serve to cut out holes on the longitudinal edges of a template carrier 11 (FIG. 5), with which the finished template carrier 11 can be inserted into a self-clamping frame, for.
• the Screenfix Handling System or the Platefix system from PRSS-Machinen AG, Winterthur, Switzerland can be attached and unclamped.
• the mesh size a (FIG. 5) of the template carrier or screen 11 is determined and varied by the spacing of the grooves 2, 3.
• the maximum width b (FIG. 5) of the webs 12 is determined by the maximum width c (FIG. 3c) of the grooves 2, 3.
• Template plates 11 are preferably produced with flat plates 1, in which reinforcement 9 (FIG. 2) is not required or, as with honeycomb-like structures, is not possible.
• a rotatable cylinder 7 (FIG. 2) is used as the basic shape; with him the "longitudinal" grooves 2 are incorporated as peripheral grooves, while the perpendicular grooves 3 extend along surface lines.
• reinforcement threads or wires 9 are inserted into the peripheral grooves 2 as far as possible, which are embedded in the plastic when the grooves 2, 3 are filled with liquid plastic.
• This reinforcement 9 has the task of improving the dimensional stability of the template carrier 11, particularly in the case of tensile loads.
• the grooves 3 only extend over a central region 8 of the cylinder jacket, while the edges 10 are recessed at least approximately to the depth of the groove in a step-like manner.
• Reinforcement threads 9 also run over part of the width of the edges 10 To achieve edge reinforcement in the screen or stencil holder 11.
• FIG. 3a Semicircles (FIG. 3a) or circular segments, to which rectangular cross sections for deepening the grooves 2,3 are connected (FIG. 3b) have proven to be useful as cross sections for the grooves 2, 3.
• FIG. 3 c cross-sections that widen conically from a segment of a circle
• FIG. 3d 2.3 V-shaped (FIG. 3e) and / or asymmetrical cross sections (FIG. 3d) for the grooves.
• the pitch, shape and depth of the grooves 2 or 3 in one direction are the same, but can be different for the two different directions.
• FIG. 4 shows an enlarged view of the surface of the cylinder 7 of FIG. 2, which represents the negative shape for the template holder 11 of FIG. 5.
• the peripheral grooves 2 provided with reinforcing wires 9 run vertically in FIG. 4; furthermore, the raised parts 13 of the surface, which in the positive result in the mesh openings h of the stencil carrier 11, are highlighted in FIG. 4 by a tint.
• a warp beam 21 with a brake 22 is provided, of which the Reinforcement threads 9 are pulled off and inserted into the grooves 2 (FIG. 2) of the rotatable cylinder 7.
• a reed 23 is provided between the two cylinders 21 and 7, through which the threads of the reinforcement 9 are arranged and guided.
• the drive of the system which is not shown, and which bears a certain similarity to a weaving machine, is carried out by a switch tree 24 which is arranged downstream of the cylinder 7.
• the inlet 27 of the reinforcement threads in the direction of rotation of the cylinder 7 is preceded by a coating channel 26 through which liquid plastic is introduced into the grooves 2, 3, distributed over the entire length of the cylinder 7.
• the thickness d (FIG. 5) of the template carrier 11 can be changed to a certain extent, in addition to the groove depth, by varying the proportion of solids in the liquid plastic.
• a scraper knife 28 is arranged downstream of the inlet 27, which is connected to the channel 26 via a line 29 for returning this plastic.
• the cylinder 7, the grooves 2, 3 of which are filled with liquid plastic After passing the stripping knife 28, comes into the effective range of a curing device 30, which consists, for example, of a heat or a radiation source.
• a curing device 30 which consists, for example, of a heat or a radiation source.
• the template support 11 is cured at least to the extent that it is dimensionally stable.
• the template carrier 11 then arrives in a curing chamber 31 for final curing via the switching tree 24 and the pressure trees 25, which also again contains a heat or radiation source.
• the finished template holder 11 is finally wound up on a goods tree 33 via a deflection tree 32, which is driven by a non-positive drive, for example a slip, not shown.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Printing Plates And Materials Therefor (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=4236711

Family Applications (1)

Country Status (10)

Cited By (2)

Families Citing this family (4)

Citations (3)

• 1992
  • 1992-08-18 CH CH256792A patent/CH684527A5/de not_active IP Right Cessation
• 1993
  • 1993-07-13 TW TW82105571A patent/TW258691B/zh active
  • 1993-08-11 AU AU45567/93A patent/AU4556793A/en not_active Abandoned
  • 1993-08-11 EP EP93915631A patent/EP0620783B1/de not_active Revoked
  • 1993-08-11 JP JP6505724A patent/JPH07502946A/ja active Pending
  • 1993-08-11 WO PCT/CH1993/000201 patent/WO1994004361A1/de not_active Application Discontinuation
  • 1993-08-11 DE DE59304301T patent/DE59304301D1/de not_active Expired - Fee Related
  • 1993-08-11 BR BR9305600A patent/BR9305600A/pt not_active Application Discontinuation
  • 1993-08-11 CA CA 2120158 patent/CA2120158A1/en not_active Abandoned
  • 1993-08-18 CN CN 93116435 patent/CN1084454A/zh active Pending

Patent Citations (3)

Non-Patent Citations (2)

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