DE102006041771B4 - Method for producing a matrix or male mold - Google Patents

Abstract

A method for producing a die or Patrizenform in a rotary embossing device in a printing press or rotary punching machine, wherein in the printing press or punching a finished formed female mold (A2) or male mold (A3) is mounted on a first cylinder as a starting shape, wherein further on a second counter-mold having a non-deformed surface of a molding compound is secured to the first cooperating cylinder, and wherein the corresponding counter-mold is formed by pressing the finished formed starting mold in the rotary embossing device under pressure against the undeformed and deformable and mounted on the second cylinder molding compound and thus the counter-mold is produced to the initial shape on the second cylinder by an impression, wherein after formation of the counter-mold to the initial shape, the stamping plate produced in the punching or printing machine relatively moved to a radiator device kneading or hardening, characterized in that during this molding of the counter-mold from the starting mold in the counter-formed mold (A2) for later recording of the substrate to be embossed a correspondingly necessary enlargement as overfilling between male mold (A3) and female mold (A2) by a method or positioning of register devices is generated over a defined travel path at least in the circumferential and axial direction of the cylinder carrying the male mold (A3) or the female mold (A2).

Description

The invention describes a method for producing a stencil form within a sheet-fed rotary printing press or rotary punching machine.

When embossing is generally between the embossing (the embossed relief protrudes beyond the substrate surface) and the deep embossing (a depression is embossed in the substrate) a distinction. The embossing mold with the raised embossing elements is called Patrize, the counter-mold with recesses die. In some cases, counterforms that have elastic or other deformable properties but no depressions are referred to as a die. Matrix is therefore generally the counterpart to the patrix. Most applications require embossing, especially when haptically detectable information, e.g. B. by Braille, to be transported.

Most often embossing and punching techniques are performed in separate machines, but for various reasons, there is always a desire to carry out these forming changes of the printing material in the printing press. Applications of these techniques within the printing machine are well known.

In DD 231 760 A1 a method for embossing on sheetfed offset printing machines is described, in which on the impression cylinder of a printing press suitable for embossing bimetallic plate (male) is glued and a blanket on a blanket cylinder of a printing unit or a forme cylinder of a coating unit serves as a die. This application has the disadvantage that the gluing of the plate on the impression cylinder is very complex and a later register correction is very difficult. A disadvantage of printing presses with double-sized counter-pressure cylinders is that two patricks must be fitted accurately.

In DE 201 11 983 U1 is a printing machine described, the impression cylinder are protected by a special protective film against the mechanical effects of the forming tools. Here, a high embossing is not possible because to the embossing mold would have to be on the impression cylinder.

Protective mechanisms for cylinder surfaces of a printing press arise DE 198 26 974 C2 and DE 102 11 991 A1 , There, the reciprocal application of protective films on counter-pressure or forme cylinder for the cases of a high or low embossing is described. The disadvantage here is further that for embossing in a printing press with double-sized impression cylinders two forms must be accurately fitted on the impression cylinder.

In DE 44 35 307 C2 discloses a method and an apparatus for perforating, punching and embossing, wherein the mechanical processing of the printing material takes place in the printing press before the actual printing process. The problem that printing ink deposits on the forming tools, so that is not given, since only the unprinted substrate is deformed. However, there is the problem that the embossments are at least partially equalized by the print run through the subsequent printing units.

In DE 41 38 278 C2 After the last printing unit, a printing press is equipped with a coating unit that can be used for varnishing, punching, creasing or perforating. Since most products have to be painted, simultaneous mechanical deformation of the substrate and a coating process are not possible. The optional use of the coating unit can only be used for a very small proportion of print jobs. It is also disclosed to pre-classify the varnishing unit a sheet turning device, ie the sheet can be fed to the coating unit with the recto-impression side. For embossing or grooving in machines with double-sized counter-pressure cylinders and a protective overlay on the impression cylinder, an elaborate assembly of the embossing molds for a proper machining is required. In the case of embossing or embossing, an embossing or scoring mold can be used, which is clamped on the forme cylinder of a printing press.

In the DD 95 851 A1 a sheet-fed rotary printing machine is described, wherein a punching unit is connected to the sheet-fed rotary printing press via a coupling. Similar solutions of the combination of punching with sheetfed presses are also from the US 3,832,944 A , of the DE 20 2004 018 764 U1 and from the DE 20 2004 018 763 U1 known. A disadvantage of these solutions, however, is that the punching units are expensive special machine units and these are rather a hindrance to operation of the printing machine without mechanical deformation of the printing stock.

From the US 4,084,500 A Furthermore, a synthetic plastic is known, which is arranged on a rotating counter embossing roller. In this case, a counterstay mold made of plastic is molded from a stamping mold and hardened by a UV lamp in a printing device. The printing device has register means for positioning the embossing rollers relative to one another.

Furthermore, from the post-published DE 10 2004 029 036 A1 a tool sheet known. The tool plate is intended for rotary processing and finishing of substrates and packaging. The tool plate is coated over the entire surface with deformable plastic for producing a stamping mold and can be hardened by aftertreatment wear.

In this context, curable molding compositions have become known. Hardenable molding compounds are semi-finished products which are stable in storage, deformable and can be hardened to form parts after deformation. Such molding compounds are well known in virtually all industries. Molding compositions are prepared on the basis of polyolefins or polyolefin blends, resins and elastomers. As curing mechanisms, the radical or thermal curing are known.

In two-component processes, the molding compound is mixed with a hardener shortly before application and then cured. Various admixtures are possible to these molding compounds, which give them certain characteristics. Thus, for example, molding compositions with ceramic admixtures or fibrous materials are known which increase the stability of the molding compound after curing, or admixtures such as silicones, which are intended to reduce the adhesion of the molding compound to the embossing body.

There are also thermoplastic molding compositions are known which are hard at ambient temperature and are deformable after heating by a suitable device. After the deformation process, these cool again and deformed return to the initial hardness state.

In color printing, the successive printed images must be printed matching each other. For this purpose, a corresponding forme cylinder is adjustable with respect to its circumferential, lateral and oblique register in rotary printing presses. This is true apart from solutions in which the pressure plate itself is adjustable on the forme cylinder. Such register adjustment devices are today in almost all rotary printing presses state of the art.

It is possible to use two photopolymer plates as a mold and counter-mold in a printing press, one plate being in the form of a male and one plate being in the form of a female mold. The die or the patrix can now be clamped on the blanket cylinder in the printing unit of a printing press or on the forme cylinder of a coating unit within a printing press or fixed in another suitable manner. The counter-mold is then clamped on the impression cylinder or fastened in another suitable manner.

The problem with such a procedure lies in the fact that the male and the female mold show opposing shapes. However, the different panels show a distinctly different development behavior due to the different area coverage. As a result, the setup process of the two opposite plates to each other is very complicated and requires frequent subsequent corrections. One way out of this dilemma is to use a lot of small counter-molds that align with the embossing mold previously set up for the print image, i. H. for a patrix with, for example, twelve embossing motifs, in the worst case twelve small-part counter-forms are set up.

This described problem is further increased when the mold and counter-mold are used for embossing in rotary printing or punching machines which have a double-sized impression cylinder. Due to the double size, a plate must be set up on each cylinder half. As a result, the above problem of the setup is again significantly tightened.

• – Verwerfungen im Bedruckstoff treten teilweise durch eine fehlende Überfüllung der Matrizenform auf
• – Wenn zwischen Matrize und Patrize durch die Matrizenherstellung mittels direkter Pressung keine Aussparung für den zu prägenden Bedruckstoff erzeugt wurde, kann es bei einigen Bedruckstoffen zu Verzerrungen kommen.

Individual problems of process engineering provide hints for adjusting the preparation and embossing for different materials.

• - Faults in the printing material occur in part due to a lack of trapping of the matrix form
• - If no recess for the substrate to be embossed has been produced between the die and male part by die production by means of direct pressing, distortions may occur in some substrates.

The object of the invention is therefore to find in a method according to the preamble of claim 1 ways to significantly reduce set-up times in setting up or preparing a mold in a rotary punching machine or in a rotary printing machine and at the same time to increase the uniformity and quality of the embossing process ,

This object is achieved by the features of claim 1. Advantageous developments of the invention will become apparent from the respective dependent claims.

To solve the problem, either the die or the male of an embossing mold is formed by a molding compound, which is embossed by means of the corresponding counter-shape in the printing press and then cured in the deformed position on a printing press cylinder.

Alternatively, the die / male can be formed of a thermoplastic material which is heated to the extent that it can be permanently deformed by the embossing process before or during embossing of the counter-mold.

For curing, a variably usable emitter is preferably used, which can be inserted into and removed from the printing press in order to strengthen the deformed surface of the embossing plate and the embossing plate as a whole for the later working process.

According to the invention, in the form of the die, the correspondingly necessary overfilling for later recording of the substrate to be embossed between the male and female molds is produced by a method or positioning register means of the device carrying the male in all directions about a defined travel. As a result, the contour of the matrix is deliberately enlarged when the matrix is formed.

Thus, the male and female are optimally adapted to each other, whereby the uniformity of the embossing process over the entire surface is increased. Both the homogeneity over the entire embossing area and the precision of the embossed patterns in the substrate are improved to an unprecedented extent.

The invention will be explained by way of example with reference to drawings.

Show in it

1 an embodiment of an embossing device,

2 a schematic of a sheet-fed rotary printing press and

3 to 5 one scheme of an embossing process,

According to the invention, as in 1 shown alleviates the problem presented, for example, in which a male A3 with embossed motifs A1 is established in a first step to the printed image. The counter-mold, in this example, a die A2, is then formed by pressing the male part A3 into a molding compound which is thermally, reactive or free-radically hardened after forming the counter-mold so that the counter-mold (die A2) is permanently retained remains. For each embossing, however, an overfilling A5, ie a clearance between the die and the counter-mold is necessary, in which the material to be deformed can nestle. For this purpose, at least in the X and Y directions or in the planar extent of the embossing form, an enlargement of the counterform (die A2) is necessary. This overfill A5 in the countermould (die A2) is generated during the countermoulding process (die A2) by using the registration of a cylinder in a printing press which carries the male A3 with the embossed motifs A1. This cylinder is systematically moved by means of its respective so-called register drives in the X and Y directions, ie in its circumferential and axial direction. As a result, a counterform is formed in the molding compound, which forms a mating contour to the embossing stamp, but is increased in total by the travel of the cylinder in each direction.

An additional characteristic of the overfilling A5 in the Z direction can be generated by a change in the provision of short term more supply pressure between the cylinders is generated as needed for the subsequent embossing process. In the actual embossing operation, the embossing punch in the X and Y direction is centered and the provision (Z direction) is taken back as far as required for the embossing operation.

The described production method for a stamping mold can in a printing machine according to 2 be applied. The printing press has several printing units 3 on, in each of which a counter-pressure cylinder 1 is arranged. The impression cylinder 1 are each a rubber cylinder 4 and a plate cylinder 5 associated with not shown inking and dampening. Furthermore, following the printing units 3 a coating plant 2 provided by the impression cylinder 1 a form cylinder 10 assigned. All printing works 3 or the coating unit 2 are in operative connection with the impression cylinders 1 by means of so-called sheet transfer drums 6 coupled together for transport of printed sheets. The sheets are in a feeder 7 from a sheet pile 8th via a conditioning drum 9 the first printing unit 3 or its impression cylinder 1 fed. After completion, the sheets are stacked up again in a sheet delivery.

The embossing mold can be in a pressure gap between a rubber cylinder 4 and an impression cylinder 1 or between a form cylinder 10 and an impression cylinder 1 manufactured and used.

Possible embossing methods are in the 3 to 5 shown. 3 shows here accordingly 1 an embossing from below, wherein an embossing motif A1 on a male A3 cooperates with an upper die A2. Male A3 and female A2 can be fixed to each other with control points A4. The embossing mold thus shown acts on the printed sheet B and deforms it corresponding. In this case, the printed sheet is pulled from its underside into the area between male A3 and female A2. Thus, a so-called embossing is generated, wherein the embossed pattern thus produced from the surface of the sheet protrudes upward.

4 shows a reverse arrangement 3 , Here an embossing takes place from above, wherein an embossing motif A1 interacts on a male part A3 with a lower die A2. Thus, a so-called embossing is generated, wherein the embossing pattern is recessed into the surface of the sheet. An embossing method according to 4 can also be performed in an elastic mating surface as a die. In this case, however, poorer qualities of the embossing result are achieved.

5 shows structure embossing from above, wherein the embossing motif is a planar structure on a male A3, which cooperates with a flat or elastic die A2. Here, the sheet is provided from its underside with a flat pattern, the so-called texture embossing.

All of the processes listed here are carried out as blind embossings, with only one pattern being formed in the printed sheet without at the same time performing a coloring of the surface.

The Verfahrregime to form the counter-form can run either manually or automatically. It is even conceivable optimal design of the travel by an algorithm in the machine control or the control center computer or in a separate computer is deposited, which calculates the optimal travel, taking into account the material thicknesses to be embossed.

The curing, crosslinking or drying of the molding composition can be achieved or supported by the molding compound with a suitable dryer, for. B. in the thermal drying with an IR radiator and / or a hot air dryer, in the radical curing with a UV lamp, heated or cured. In this case, mobile dryer units, for example in the form of a hand lamp, or in the printing press permanently installed dryer units can be used. These permanently installed dryer units are ideally directed in the direction of action against the cylinder of the printing press, which carries the molding material.

The dryer units are preferably designed as compact radiators, which can be easily mounted in the punching or printing press.

The installation of a radiator is preferably carried out with respect to the counter-pressure plate or plates bearing impression cylinder 1 , The arrangement can be made so that it comes to lie, for example, below a sheet guide path of the punching or printing machine. In this case, the radiator may be perpendicular or oblique and upstream or downstream of the cylinder.

The advantages here are lower expenses for the shielding of the elements of the machine against heat radiation and for occupational safety measures. In addition, this results in no restriction of the operating space of the machine operator.

A radiator can be arranged fixed or removable. Also conceivable is a pivoting device according to existing functional units such as washing devices, coating devices or blowing devices. Here, a corresponding existing holder for the spotlight can be used.

Furthermore, spotlights can be placed on cars, so that they can be moved between different machines and between the working units of the punching or printing presses.

The advantage here is that can be embossed in any printing unit or can be worked on any machine. This results in maximum production flexibility when investing in just one spotlight.

The radiator can remain on the carriage or be removed from there and stored in a holding device. It would be advantageous, however, if he remained on the car.

Finally, an automatic coupling of the radiator for energy or equipment supply via line or plug is possible. A corresponding coupling device may be connected to the carriage or the punching or printing machine.

Regardless of the arrangement, the radiator should either cover the entire area of the impression cylinder 1 Regarding its axial length irradiate. This can with rotation of the impression cylinder 1 the stamping plate are dried or cured relatively quickly.

Likewise, the radiator can only a portion of the impression cylinder 1 irradiate. The irradiation time is relatively short (about 1 to 3 minutes). Furthermore, the spotlight is needed only once per job. So it is also conceivable to let the spotlight traverse across the machine width. This would have the significant advantage that only a small mobile unit with simplified control is needed.

By contrast, the full width of the spotlight limits its mobility (for example through more heavy-weight transformers).

The corresponding assignment can, of course, also at any other cylinder to be produced representing counter-mold embossing plate as the impression cylinder 1 respectively.

The molding material itself can be plate-like on a support, for example, a plastic or metal support, are located, which is then stretched or glued to the cylinder, which will later wear the die A2. The molding compound may itself have sticky properties, so that it adheres to the cylinder due to the material properties. The molding compound may be provided with an adhesion promoter so that it remains adhered to the cylinder by means of this adhesion promoter.

For better separation between the male and the molding compound in the embossing process of the die, the male and / or the molding compound surface can be provided immediately before and / or the embossing process with a release agent which prevents the adhesion of the molding material to the male.

In a particularly advantageous manner, the release agent may also be suitable for this purpose and thus used in a targeted manner, that when embossing in coated surfaces of a printed sheet, a transfer of laminates from the printed sheet to the stamping mold is prevented or at least suppressed. This reliably prevents contamination of the embossing mold and, as a consequence, splitting back to subsequent sheets. The printing or processing quality of the process continues to increase.

This sheet or substrates that are already provided with printing ink, paint, brighteners, films, protective layers or the like, without the risk of contamination of the embossing molds or an unwanted transfer of layer elements can be precisely defined.

In a second embodiment of the invention is used as a deformable material, a thermoplastic plastic, a thermoplastic elastomer or a thermoplastic foam, which is heated to the extent of the embossing process with the male mold - analogous to the stamping process of the molding material, that it deforms permanently by the embossing process leaves and the embossed shape after cooling to ambient temperature is permanently maintained. The formation of the trapping of the female mold can be generated analogous to the procedure with the molding compound by a Verfahrregime in X and Y direction and optionally in the Z direction of the register setting of the cylinder and the provision of the cylinder to each other.

Thermoplastic elastomers (linear elastomers, abbreviated TPE) are plastics that behave at room temperature comparable to the classic elastomers, but can be plastically deformed under heat, and thus show a thermoplastic behavior. Thermoplastics are plastics that can be plastically deformed under the influence of heat.

As a rule, thermoplastics consist of polymers of linear or less branched chain molecules. When heated, they can be stretched by pulling. With increased warming, they can be melted down indefinitely and reshaped. Therein they differ from the thermosets.

The heating of the thermoplastics, the thermoplastic elastomers or thermoplastic foams can by thermal radiation, for. B. by means of an IR radiator and / or done by hot air with a suitable device. The device used for this purpose can be mobile, for example, as a handheld device, used or permanently installed in the printing presses.

The following is an application example of a stamping mold generation:
In sheetfed offset presses, embossing can be generated in printing or coating plants. For this purpose, for. B. embossing tools applied to the forme cylinder of the coating unit, which act against the counter-pressure cylinder or a material applied to the impression cylinder material or there applied corresponding counter-mold. Accordingly, the application of embossing tools in the printing unit.

• – Eine Patrize wird auf einen Zylinder (Form-, Gummi-, Gegendruckzylinder) der Bogendruckmaschine gespannt
• – eine teilvernetzte (oder unvernetzte) Photopolymerplatte (rohe Prägeplatte) wird auf den korrespondierenden Zylinder gespannt
• – Eine formschlüssige Matrize, also komplett dem Gegenbilder einer Patrize entsprechendes Prägewerkzeug, wird erzeugt, indem die Patrize abrollend in die Photopolymerplatte gepresst wird.
• – Die Photopolymerplatte wird hierzu mehrfach überrollt
• – Dann wird die Photopolymerplatte mit UV-Licht belichtet und ausgehärtet.
• – Die Matrize ist so passgenau an Ihrem Platz verbleibend in der Druckmaschine angebracht.

The following setup procedure is required for embossing.

• - A male is clamped on a cylinder (form, rubber, impression cylinder) of the sheet-fed press
• - A partially crosslinked (or uncrosslinked) photopolymer plate (raw stamping plate) is stretched on the corresponding cylinder
• - A form-fitting die, so completely the counter-images of a male corresponding embossing tool is generated by the patroller is rolling pressed into the photopolymer plate.
• - The photopolymer plate is rolled over several times
• - Then the photopolymer plate is exposed to UV light and cured.
• - The die is fitted in the printing machine so it fits perfectly in its place.

• 1. wasserauswaschbare Platten auf Stahlträger, Gesamtstärke von 0,73 mm.
• 2. alkohol-auswaschbare Photopolymerplatte auf Stahlträger, Stärke 0,73 mm; unvernetzt weichere Photopolymerschicht als wasserauswaschbare Platte.
• 3. Photopolymerplatte (im Zeitungsdruck eingesetzt) mit Aluminiumträger; unvernetzt sehr weiche, wachsartige Photopolymerschicht, Gesamtstärke 1,27 mm.

For the matrix to be produced different photopolymer materials come into question:

• 1. Water washable panels on steel beams, total thickness of 0.73 mm.
• 2. Alcohol washable photopolymer plate on steel support, thickness 0.73 mm; uncrosslinked softer photopolymer layer than water-washable plate.
• 3. Photopolymer plate (used in newspaper printing) with aluminum support; uncrosslinked very soft, waxy photopolymer layer, total thickness 1.27 mm.

The forming patrix can be made of a photopolymer plate. The motifs and contours to be embossed are mounted on a non-distorted flexo film of the right side and exposed to UV light. The unexposed areas of the photopolymer plate are washed out. Relief depths of 0.40 mm are adjustable. The cliché has a Shore hardness of 79 (Shore D) and the relief layer according to DIN a Shore hardness of 65 (Shore A). Likewise, the male can be made of metal or other materials.

In the setup process, different underlay thicknesses are used, which were stretched under the patrix to obtain a recognizable embossed image. The pressure can be determined by adjusting means for adjusting the printing on printing presses. Thus produced matrices are then exposed (eg 2 minutes in the tube exposer). A measurement by means of an etching depth microscope shows the embossing quality.

An improvement for the stability of the male and also the stamping result and the Matrizenherstellung results when the male is produced as a metal mold. This may be advantageous, despite the higher cost of producing high volume products.

Furthermore, it is possible to use the die as a starting shape and to stamp its contour in the present as a raw male. In this case, the above-mentioned very soft printing plate from the newspaper printing can be used advantageously, since this allows easier deformation.

LIST OF REFERENCE NUMBERS

A1

Prägemotiv

A2

die

A3

punch

A4

control point

A5

overcrowding

1

Impression cylinder

2

coating unit

3

printing unit

4

rubber cylinder

5

plate cylinder

6

Transferier

7

investor

8th

stack

9

feed drum

10

Form cylinder (coating unit)

B

substrate

Claims (6)

A method for producing a die or Patrizenform in a rotary embossing device in a printing press or rotary punching machine, wherein in the printing press or punching a finished formed female mold (A2) or male mold (A3) is mounted on a first cylinder as a starting shape, wherein further on a second counter-mold having a non-deformed surface of a molding compound is secured to the first cooperating cylinder, and wherein the corresponding counter-mold is formed by pressing the finished formed starting mold in the rotary embossing device under pressure against the undeformed and deformable and mounted on the second cylinder molding compound and thus the counter-mold is produced to the initial shape on the second cylinder by an impression, wherein after forming the counter-mold to the initial shape, the embossing plate produced in the punching or printing machine relatively moved to a radiator device kneading or hardening, characterized in that during this molding of the counter-mold from the initial shape in the counter-mold (A2) for later recording of the substrate to be embossed, a correspondingly necessary enlargement as overfilling between the male mold (A3) and female mold (A2) a method or positioning of register devices is generated over a defined travel path at least in the circumferential and axial direction of the cylinder carrying the male mold (A3) or the female mold (A2). A method according to claim 1, characterized in that a thermally drying composition is used as the molding composition and the drying of the molding composition after formation of the counter-mold is accelerated by a Heißlufttrocknungs- and / or an infrared radiation device. A method according to claim 1, characterized in that a free-radically curing molding composition is used as the molding composition and that the radical curing of the molding composition after the formation of the counter-mold is triggered by a UV curing device. A method according to claim 1, characterized in that the molding compound is a photopolymer printing plate which is curable by means of radiation, wherein the photopolymer printing plate a Working layer on a support containing a wasserauswaschbares or an alcohol-washable photopolymer. A method according to claim 1 to 4, characterized in that the one- or multi-part starting form is mounted in a simple design on a simple large cylinder, such as the blanket or blanket cylinder of an offset printing unit or the forme cylinder of a coating unit and that the raw counter-mold in duplicate two working surfaces of a double-sized impression cylinder is mounted and that takes place during the stamping of the counter-mold, a multiple overrolling of the two raw counter-forms by means of an initial form. Method according to one of the preceding claims, characterized in that applied for producing the counter-mold to the starting form a release agent on the arranged after the embossing process on a cylinder output form and / or the counter-mold produced on the corresponding cylinder and after the completion of the counter-mold there during embossing as Protection against contamination is used.

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