EP0930161B1 - Method and device for coating printed products - Google Patents

Description

The invention is concerned with avoidance or reduction due to production loads, e.g. by wiping or scrubbing color abrasion caused by an offset printed product in the Inline process in the production of the printed product as well with rewetting the paper after drying the Paint.

For example, rubbing is caused by movements of printed sheets caused on a vibrating table. He understands by wiping Expert abrasion due to one-time loads, e.g. by touching with production management elements for further processing of the freshly printed product.

The color abrasion is essentially influenced by the parameters Substrate, printing ink and production load during further processing after the paint application.

Regarding the printing material, there are especially matt-coated ones Papers that have been in use since the 1980s - for better readability and more natural effect of the pictures - more and more than Substrate can be used from unwanted ink abrasion affected. The lack of abrasion resistance is due to the Surface texture of the matt coated papers that is relatively rough and diffusely reflective. A purpose of the invention is therefore especially the abrasion resistance of printed products to improve on matt coated papers.

The printing ink can be more abrasion-resistant thanks to special formulations be designed. The invention is concerned with this parameter but not.

In contrast, the invention is concerned with reducing the effects the mechanical loads on the printed product drying the paint.

In the web offset printing process, e.g. the Turning bars, deflection and guide rollers as well as folding units Print product by wiping immediately after drying. Also subsequent means of transport and disposal of the printed matter from the printing press e.g. through buffering as well the usual further print finishing can be wiped - and cause abrasive processes.

In the sheetfed offset printing process, the sheets are after drying laid out on pallets and transported for further processing. In particular, abrasion occurs. This printing process also poses additional burdens the usual print finishing, e.g. in the folding machine, in the collator, in the perfect binder, in the trimmer and in the thread sewing machine.

It is known to avoid or reduce paint abrasion due to mechanical loads protective layers on the printed Apply product. Lacquer coats are used, Laminations with plastic foils and sliding emulsion layers.

Lacquer layers provide good protective effects against abrasion; however, they must be applied in considerable thickness because thin layers of lacquer in a homogeneous distribution on the surface of the printed product cannot be achieved.

Varnishes for another purpose, for example for blister varnishing, are applied using chambered doctor blade technology, among other things. A combination of an aluminum chamber filled with lacquer, an anilox roller for lacquer application, a lacquer forme cylinder and a printing cylinder is essentially used. Anilox rollers with a scoop volume of 6.5 cm ³ / m ² are available for the smallest order quantities for the purposes mentioned (MAN Roland revue No. 39 / May 1997, page 8). With this technique, a protective layer in question according to the invention, which may have to be applied even thinner, because otherwise the quality of the product would be changed, cannot be achieved in a homogeneous distribution.

Currently known slip emulsions reduce the Friction between product surface and processing equipment. They can be applied much more cheaply will only bring about a relative improvement in the color abrasion resistance and insufficient protection.

Laminations with plastic films (lamination) result in the safest protection of the paint application against mechanical product loads, However, scratches can occur in the laminate Affect the printed image. In addition, in contrast to the Painting and applying a sliding emulsion the lamination cannot be carried out inline. In this respect there is also the lamination not optimal and also very expensive.

The invention aims in particular to improve the protective effect of sliding emulsions, especially on printed matt-coated ones Papers, but also the application of a Lacquer layer possible and simplified according to the invention and the Effectiveness of the lacquer layer should be increased.

It is known to use the web offset printing process after drying a silicone emulsion layer with so-called roller applicators to be applied as a coating system. Such coating systems usually have an approximately 100 mm thick chrome roller with a smooth surface on, with the upstream and downstream Paper guide rolls the paper web in a certain wrap angle range to be led. The chrome roller dips outside the paper web wrapping area with its outer surface partially in a silicone-water mixture (silicone emulsion) and takes silicone emulsion as it rotates on their lateral surface, which they use on the emits printed paper web surface. The order quantity can can be varied by moving the chrome roller in the opposite direction or in the opposite direction the direction of travel of the paper web is driven, wherein the speed of rotation is also varied. It can the paper web speed up to 15 m / sec. to reach. The Chrome roller speed is only about 1% of that means maximum 15 cm / sec. It could be within the scope of the present Invention are found to be highly diluted with water Silicone compounds cause a rejection reaction on certain surfaces As a result, the color applied causes the color remains unprotected there.

With this well-known silicone emulsion coating process the product receives some protection against premature Ink abrasion on guide rollers and in the former, the Wipe and abrasion resistance is only relatively minor elevated. To improve the protective effects are hydrated Sliding emulsions have been developed in addition to a low Silicon content have a high wax content or only Have wax and also applied with roller applicators become.

Both with the silicone emulsion application and with the silicone wax emulsion application and wax emulsion application with roller applicators there is often a visible inexplicable staining on; the emulsion coatings are not homogeneous spread on the surface of the printed matter; in places the coating is completely missing. When using silicone emulsions the visibility of the stains disappears some time; when applying silicone wax and wax emulsion Visibility remains and reduces the quality of the Printed product. The latter coatings also have the disadvantage that that due to the formation of stains, wax deposits e.g. on Guide rollers and in the former, which interfere and from Need to be removed from time to time.

To solve the problems is for the web offset printing process been proposed instead of the usual roll applicators to use a rubber applicator roller by an anilox roller is wetted. The anilox roller should be in a Immerse the scoop and scrape it off with a squeegee, before the anilox roller is contacted with the applicator roller. The success of this proposal is unknown.

The object of the invention is to provide methods and devices for Production of offset printed products with regard to inline application a protective layer on the printed surface to improve such that a protective layer with sufficient Smudge and abrasion resistance spotless and relatively thin as well can be applied homogeneously distributed, the application none high equipment expenditure.

This object is achieved by the features of claims 1 and 16 solved. Advantageous developments of the invention are in the characterized by claims dependent on these claims.

The application of a protective layer according to the invention is both in sheetfed offset printing machines as well as in web offset printing machines integrable (inline). The is particularly advantageous Use in web offset printing presses after the cooling device or downstream of the cooling rollers.

The method according to the invention and the device according to the invention work spotless with UV paint formulations and paint dispersions as well as with silicone, silicone wax and wax emulsions. However, use with silicone wax is particularly effective. and wax emulsions. It has been surprising We found that emulsions with higher silicone wax concentrations than when applied with roller applicators will result in better protective layers. The emulsions are usually with concentrations between 35 and 40% Silicone oil or wax content delivered. Dilutions up to about 10% are effective according to the invention. Emulsions with 8% silicone oil and / or wax content are rejected. Especially Concentration fractions between 10 and 30 are preferred, preferably between 15 and 25%.

The invention is particularly applicable to offset printing products, paper as matt or semi-matt coated paper exhibit. The invention is particularly effective when used of matt papers as printing material.

According to the invention, an anilox roller with a doctor device used for the application of the protective layer, being essential is that the transfer of the protective layer medium to the printed product directly, that is, without interposing another Roller, e.g. a rubber roller or a forme cylinder from the Anilox roller takes place. It is also essential that the application in opposite driving style of the anilox roller with respect to the printed Product e.g. the paper web or sheet of paper carried out becomes.

In particular, this combination of selected, known per se Procedures provide the solution to the long-known Problem, effective protective layers with relative stain-free to produce simple means that are sufficiently wiped and are scrubbable that they themselves have no significant pollution the subsequent processing facilities for the Print products cause and also the ink application protect mechanical loads.

The counter-rotating peripheral speed of the anilox roller is expediently about 30 to 100%, in particular 80 to 100% of the Running speed of the printed product e.g. the paper web or the paper sheet.

The use of an anilox roller provided with a ceramic coating, a so-called ceramic anilox roller, which is laser-engraved, is particularly advantageous. For the purpose according to the invention, the well engraved laser engraving is preferably produced with 120 to 180, in particular 140 to 160 lines per cm, which can transfer approximately 9 to 5 g / m ^{2 of} protective layer emulsion. It is advantageous to provide grids with a grid angle between 45 and 60 ° and cells in honeycomb form.

According to the invention, a paper wrap angle is on the anilox roller from 3 to 25 °, preferably from 6 to 18 ° for roller diameters from 180 to 220 cm, in particular from 190 to 210 cm used.

A chambered doctor blade known per se is particularly advantageous. expediently also a so-called pressure chamber doctor device to combine with the anilox roller used according to the invention.

Fig. 1

schematisch eine Seitenansicht einer Schutzschichtauftragsanlage;

Fig. 2

schematisch eine Seitenansicht des Auftragswerks einer Auftragsanlage;

Fig. 3

schematisch eine an sich bekannte Rollenoffsetdruckmaschinenwalze mit Inline-Anordnung einer Schutzschichtauftragsanlage von der Seite betrachtet.

The invention is explained in more detail below using the drawing as an example. Show it:

Fig. 1

schematically shows a side view of a protective layer application system;

Fig. 2

schematically shows a side view of the application work of an application system;

Fig. 3

schematically viewed from the side a known web offset printing press roll with inline arrangement of a protective layer application system.

In a web offset printing press shown schematically in FIG. 3 is from a reel changer 1 at least one paper web 3 into a drafting system and from the drafting system into printing units 5 promoted. After printing on the paper web 3 in the printing units 5 runs the printed product into a dryer 6, in where the paint is dried or solvent from the paint to be driven. The printed paper web then arrives 3 with the dried paint in a cooling unit 7 and from there in a rewetting system 8, a protective layer application system 9 and finally into a folder 10. In the folder 10 the paper web 3 is cut, folded and laid out. It usual further processing then takes place End product, the printed product.

In the dryer 6, the fresh application of paint under the influence of Heat energy solidified. For this, the paper web with hot air heated to about 140 ° C. With this hot air drying the Original moisture of the paper from 3.0 to 4.5% undesirable 0.5 to 1.0% absolute humidity reduced. A paper moisture in the A range of 3.0 to 4.5% is necessary to ensure the optimal Paper properties such as Dimensional stability and impact behavior of a book or magazine can and thus the paper later no moisture uncontrolled from the environment. After cooling down the Paper web from about 140 ° C to about 20 ° C by water-cooled Rolling in the cooling unit 7 becomes the paper web 3 in the rewetting system 8 with a finest rotating water mist Nozzles moistened on both sides. The rewetting system 8 is expediently downstream of the cooling unit 7.

According to the invention, an application device is used as the application device 9 11 used according to FIG. 1. This order facility 11 has a ceramic anilox roller 12, one on the anilox roller 12 attached doctor blade device 13 and two from the anilox roller 12 spaced guide rollers 14, 15. The in the running direction 2 transported printed paper web 3 is transverse to the direction of travel 2 laterally next to the axis of rotation 16 of the anilox roller 12 the outer surface 17 of the anilox roller 12 is pressed. This is what the upstream and downstream in the direction 2 of the anilox roller 12 Guide rollers 14, 15, of which the roller 14 in the running direction and the other roller 15 is arranged behind the anilox roller 12 are. At least one of the rollers 14, 15 is perpendicular to it Axis of rotation in the double arrow direction 18 displaceably mounted. Preferably however, both rollers 14, 15 are in the double arrow direction 18 removable. The transferability can also others Directions.

With the rollers 14, 15, the paper web 3 becomes linear to flat, preferably so flat on the lateral surface 17 of the Anilox roller 12 pressed that it has a certain area of the jacket 19 or the anilox roller 12 with a certain wrap angle α spanned. Located below the transformer area 19 in the 3 or 6 o'clock position with respect to the anilox roller 12 the chamber doctor blade 13, in which the protective layer medium 21 is located and from which with squeegee medium 21 from which itself rotating anilox roller 12 is stripped, the partial areas immersed in the medium 21.

The schematic structure of a doctor blade 13 is just like one Anilox roller 12 according to the invention can be seen in FIG. 2. In one Container 20 is the protective layer medium 21. In the Medium 21 dips the anilox roller 12 laterally with a partial area next to the axis of rotation 16. On the opposite Side of the axis of rotation 16 spans the paper web 3 in the reclamping area 19 the anilox roller 12. The direction of rotation (arrow 22) of the Anilox roller 12 is preferably opposite to direction of rotation 2 the paper web 3, while the direction of rotation of the guide rollers 14, 15 (Arrows 23) is aligned with the direction of rotation 2.

If the paper web 3 is printed on both sides, it is expedient a second identical coating system or application device 11 used on the other side of the paper web 3, whose anilox roller 12, for example, instead of the guide roller 15 is arranged such that both the first and the second Anilox roller 12 with paper web 3 each determined Wrap angle α or wrap area 19 forms (not ) Shown.

According to the invention are in the outer surface 17 of the anilox roller 12 wells 24 in a very dense arrangement using laser engraving brought in. The depth and shape of the cup 24 is chosen that each well 24 receives sufficient medium 21, that is stores at least as much as sucked from the paper web 3 or should be pulled out. Form and depth are preferred the well 24 is chosen such that more emulsion in one well is present when removed from the paper web 3 can. A predetermined intake quantity of the cells 24 Emulsion 21 is in a manner known per se by the doctor device 25, 27 of the doctor blade 13 ensures the superfluous Strips medium 21 from the outer surface 17 of the anilox roller 12. As a doctor blade device 13, one in itself known pressure chamber doctor device can be used.

The cups 24 are expediently in the jacket of the anilox roller 12 shot with laser beams, preferably two shots can be used per well. From the resulting The shape of the cup 24 results in an optimal Storage capacity for e.g. a relatively light liquid wax emulsion, which tends to be generated by centrifugal force when rotating the Anilox roller 12 to be pushed out of the well 24.

According to a particular embodiment of the invention, the device according to the invention and the emulsions also for rewetting, especially used immediately after cooling. A separate rewetting system is not required. The emulsions are based on the amount of solids in the emulsion and in terms of the amount applied to the Paper web matched that both a desired optimal rewetting moisture as well as a set optimal coating. For this particularly rational working processes, emulsions are used whose solids content is empirically determined, whose composition in the rest, however, is in the range already specified above.

The use of an anilox roller thus results in a surprising Wise a synergistic effect by working in one step with the same device both specifically rewetted the protective layer can also be applied in a homogeneous distribution can.

Particularly suitable for achieving the synergistic effect are the silicone, silicone wax and wax emulsions.

In combination with the selection of the optimal amount of solids or the optimum water content in the emulsion becomes the peripheral speed the rotating anilox roller in relation to Running speed of the paper web or sheet, the Wrap angle, and the diameter of the anilox roller and matched the type of screening so that each other sets the desired synergistic effect.

Claims (19)

1. Method of producing an offset printed product, such as a book or a periodical or the like, an application of ink being printed onto a printing material made of paper, the application of ink being dried or cured, the paper possibly being rewetted and the printed product being processed further by devices operating mechanically to form a printed product, and, before the further processing, in order to form a protective layer, a protective layer medium being applied to the printed surface of the printed product on the constantly transported printed product, in line by using a driven, rotating engraved roll, characterized in that

   a) the protective layer medium is applied to the printed product directly from the engraved roll, by the printed product being guided, with a predetermined contacting wrap angle range, over the engraved roll outer surface, and

   b) the engraved roll being driven in the direction opposite to the running direction of the printed product.
2. Method according to Claim 1, characterized in that the protective layer medium applied is a varnish coating formulation or a varnish dispersion.
3. Method according to Claim 1, characterized in that the protective layer medium applied is a silicone, silicone wax or wax emulsion.
4. Method according to Claim 1 and/or 3, characterized in that a 10 to 30%, in particular 15 to 25% emulsion is applied with the engraved roll.
5. Method according to one or more of Claims 1 to 4, characterized in that it is used in line in the web-fed offset printing process after the cooling of the printing ink.
6. Method according to one or more of Claims 1 to 5, characterized in that it is used in the case of in printed products whose printing material is semi-matt to matt-coated, in particular matt-coated paper.
7. Method according to one or more of Claims 1 to 6, characterized in that an engraved roll having a chamber-type doctor device is used.
8. Method according to one or more of Claims 1 to 7, characterized in that an engraved roll which is coated with a ceramic material is used.
9. Method according to one or more of Claims 1 to 8. characterized in that an engraved roll with a laser-engraved engraving is used.
10. Method according to one or more of Claims 1 to 9, characterized in that an engraved roll which has a cellular laser engraving with 120 to 180, in particular 140 to 160 lines per cm is used, the cell shape preferably being honeycomb-shaped.
11. Method according to Claim 10, characterized in that an engraved roll having an engraving which has an engraving angle between 45 and 60° is used.
12. Method according to one or more of Claims 1 to 11, characterized in that an engraved roll having a diameter of 180 to 220 cm, in particular of 190 to 210 cm, is used.
13. Method according to one or more of Claims 1 to 12, characterized in that a wrap angle of the wrap angle region from 3 to 25°, in particular from 6 to 18°, is used.
14. Method according to one or more of Claims 1 to 13, characterized in that the engraved roll is driven with an opposite circumferential speed of 30 to 100%, in particular of 80 to 100%, of the running speed of the printed product.
15. Method according to one or more of Claims 1 and 3 to 14, characterized in that by means of selecting method parameters of the aforementioned claims for simultaneous rewetting of the printed paper after drying, an emulsion with a selected water content is used to set a predetermined optimum paper moisture.
16. Apparatus for carrying out the protective medium application method and, in particular, also the rewetting method according to one or more of Claims 1 to 15, having a driven engraved roll with drive means for the purpose in combination with a doctor device and a container that holds protective layer medium and which is arranged in such a way that subareas of the engraved roll can dip into the protective layer medium, and also having at least one rotating paper web guide roll, characterized in that the engraved roll is a ceramic-coated, laser-engraved engraved roll (12), which can be driven in the direction opposite to the running direction of the printed product, and the paper web guide roll (14 and/or 15) is arranged in such a way that the printed paper web (3) is led directly from it, with a predetermined contacting wrap angle range, onto a subarea (19) of the outer surface (17) of the engraved roll (12).
17. Apparatus according to Claim 16, characterized in that the doctor device is a chamber-type doctor device (13) which holds protective layer medium.
18. Apparatus according to Claim 16 and/or 17, characterized in that in the event that there are a plurality of guide rolls (14, 15), at least one is arranged such that it can be offset at right angles to its axis of rotation.
19. Apparatus according to one of more of Claims 16 to 18, characterized in that a guide roll (14 or 15) is the engraved roll (12) of a second, identically constructed protective layer medium application apparatus according to the invention.

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