WO2012123533A1

WO2012123533A1 - System consisting of a printing cylinder and a printing blanket or printing plate

Info

Publication number: WO2012123533A1
Application number: PCT/EP2012/054538
Authority: WO
Inventors: Stefan Füllgraf; Markus Gnass; Detlef Roeder
Original assignee: Contitech Elastomer-Beschichtungen Gmbh
Priority date: 2011-03-16
Filing date: 2012-03-15
Publication date: 2012-09-20
Also published as: WO2012123149A3; EP2686168A1; DE102011001315A1; EP2686168B1; WO2012123149A2

Abstract

The invention relates to a system (2) consisting of: a printing cylinder (4) having a gap (8) in the axial direction, and a printing blanket (6) or printing plate (6) comprising a cover layer (10) that contains a printing layer (12) facing radially outwards and a carrier layer (18), the leading end (20) and the following end (22) of said carrier layer (18) being free from the cover layer, and said leading end (20) and following end (22) of the carrier layer (18) being tensioned in the printing cylinder (4) gap (8) such that a channel (28) remains, running in the axial direction of the printing cylinder (4), between the continuous ends (24, 26) of the cover layer (10), said channel (28) being completely filled with a compressible material.

Description

description

System consisting of a printing cylinder and a blanket or a

The invention relates to a system consisting of:

A printing cylinder having a gap in the axial direction,

A blanket or printing form having a cover layer containing a radially outwardly directed print layer and a backing layer, the leading and trailing ends of the base layer being free of the cover layer,

wherein the leading end and the trailing end of the support layer are clamped in the gap of the printing cylinder such that a channel extending in the axial direction of the printing cylinder remains between the circumferential ends of the cover layer. The invention further relates to a method for producing such a system.

A system of the type mentioned has long been known from the prior art. Such systems are used both in offset printing on blankets and metal blankets as well as in high-pressure forms such. Flexographic printing applications in which the blanket has a comparatively high flexibility or compressibility.

An advantage of the system is that the blanket or printing form can first be manufactured as a two-dimensional flat surface with a beginning and an end. The production of such a blanket or such a printing form is possible in a simple way, whereas the production of an endless one

Pressure cylinder is expensive.

The disadvantage of a system of the type mentioned is, however, to be seen in that after the clamping of the blanket or the printing forme on the printing cylinder remains a channel between the peripheral ends of the cover layer. In this channel impurities such as e.g. Collect paper dust or paint that may fall out of the channel during printing, which can damage the paper webs you are printing.

From DE 103 07 382 AI a system is known in which the channel with a

Elastomer is closed. In the system known from this document, the blanket is first made from a production cylinder. This will be on the

Manufacturing cylinder initially spanned a support layer on which the cover layer is attached. Thereafter, the remaining between the peripheral ends of the cover layer channel is closed with a curable elastomer. After curing, the blanket is cut in the region of the elastomer in the axial direction of the production cylinder and removed from the production cylinder. Finally that will be

Blanket stretched on the printing cylinder so that the end faces of the elastomer are touching each other. The channel is thus also on the printing cylinder

locked. However, it should be noted that the production of the known from DE 103 07 382 AI blanket is expensive. In addition, remains between the

circumferential ends of the cover layer of the blanket in the region of the channel due to the separation of the elastomer has a narrow crack in which can collect impurities. Finally, it should be noted that the elastomer introduced into the channel is incompressible. Be forces on the blanket so in the radial direction

applied, so the elastomer can avoid these forces only in that it expands in the circumferential direction of the blanket. This leads to the introduction of undesirable forces in the circumferential direction of the blanket, which with a deterioration of the

Print image can go along. The invention has for its object to provide a system of the type mentioned, in which no impurities in the region of the top layer of the

Blanket or the printing plate can penetrate. The invention is further based on the object to provide a method for producing such a system.

The object is achieved according to the characterizing features of claim 1, characterized in that the channel is completely filled with a compressible material. In this case, the complete filling of the channel takes place in such a way that the peripheral ends of the blanket or of the printing forme are non-positively connected with one another via the compressible material.

According to the independent claim 6, the object is further achieved in that after the drawing of the blanket or the printing forme on the printing cylinder, the remaining between the peripheral ends of the outer layer structure channel is completely filled with a compressible material.

The advantage achieved by the invention is to be seen in the fact that in the field of

Pressure layer, especially in the channel, no impurities can penetrate. This is due to the fact that the channel is completely filled with a compressible material which frictionally connects the peripheral ends of the cover layer. Thus, neither in the compressible material, nor at the transitions from the compressible material to the cover layer are scratches in which contaminants can penetrate. Another advantage of the invention is that the system can be easily manufactured. In particular, it is not necessary to manufacture the blanket or the printing form on a separate production cylinder.

For producing a compressible material, various materials may be used as raw materials in combination with blowing agents. Suitable starting materials are preferably elastomeric materials such as EPDM, NBR, modified epoxy resins or silicone rubbers or elastomers based on Polyurethane or polyurea. Also, thermoplastics such as PE or PP can be used if they are compliant at the temperature of the application. As blowing agents, both chemical and physical blowing agents can be used. Physical blowing agents are understood as meaning, for example, compressed gases (eg air, CO 2 or CFC) or volatile hydrocarbons. Azodicarbonamides, sulfonylhydrazides or hydrogencarbonates can be used as chemical blowing agents.

Preferably, a combination of polyuritan or polyureas or a combination of polyurethane and polyureas with microspheres is used.

The color of the material is preferably black, e.g. by the addition of carbon black, so that it can be lasered. By laser ablation, a print template can be created on a printing form.

According to one embodiment of the invention according to claim 2, the compressible material consists of a chemically curing material, are embedded in the microspheres. The advantage of this development is the fact that you can initially fill the channel with the compressible material evenly and completely and the mass hardens only afterwards. Preferably, a chemically curing material is selected which requires a maximum of 15 minutes to cure, so closing the channel does not take too much time. The compressibility of the material is brought about by means of embedded microspheres, which enclose air. According to a development according to claim 3, the cover layer on a compressible intermediate layer, wherein in the chemically curing material so many microspheres are embedded, that the compressibility of the intermediate layer corresponds to the compressibility of the chemically curing material. In order to achieve this, so many microspheres are embedded in the chemically curing material that the density of the cured material with microspheres is 20% to 40% lower than the density of the cured material without microspheres. The advantage of this development is the fact that the compressible intermediate layer, which is the top layer of a printing blanket or a

Comprising conventional printing form, is formed homogeneously over the entire circumference of the blanket or the printing plate. This ensures that the printing blanket or printing form behaves homogeneously in all directions during a printing process.

Any chemically curing materials may be used to form the invention. In particular, it is possible to use materials that cure by irradiation. According to one embodiment of the invention according to claim 4, however, the chemically curing material is an epoxy resin, which is composed of an epoxy resin and a curing agent, being used as the epoxy polymer blocks, which carry so-called epoxide groups at the end. For this example, the reaction products of bisphenol-A and epichlorohydrin can be used, which form a stable thermoset after mixing with the curing agent containing amino or mercapto. The advantage of the development is the fact that the curing reaction can be carried out at room temperatures in a two-component epoxy resin. Another advantage of this development is the fact that epoxy resins are easy to work with and cure quickly.

According to one embodiment of the invention according to claim 5, the support layer is formed as a metal foil. The advantage of this development is the fact that the blanket or the printing plate with the help of a metal foil reliably on the

Pressure cylinder can be clamped, since the metal foil can absorb forces in the circumferential direction. According to one embodiment of the invention according to claim 7, the compressible material is formed as a two-component epoxy resin, wherein at least one component of the epoxy resin contains microspheres. The advantage of this development is the fact that two-component epoxy resins cure quickly, so that the channel between the peripheral ends of the cover layer can be quickly closed. According to a development of the invention according to claim 8, the edges of the peripheral ends of the cover layer are sealed prior to introduction of the compressible material with an elastomer. The advantage of this development is the fact that the edges of the cover layer are completely sealed with the elastomer and thus the compressible material needs to bind exclusively to a single substance, namely the elastomer. The elastomer may be selected to provide a particularly strong bond between the compressible material and the elastomer. This leads to a particularly strong frictional connection between the peripheral ends of the cover layer.

An embodiment and further advantages of the invention will be explained in connection with the following figures. It shows:

Fig. 1 shows a system consisting of a printing cylinder and a blanket or a printing plate in cross section, and

Fig. 2 shows a system consisting of a printing cylinder and a blanket or a printing plate in plan view.

Fig. 1 shows a system 2, consisting of a printing cylinder 4 and a blanket 6 or a printing plate 6 in cross section. The printing cylinder 4 has a gap 8 which extends in the axial direction of the printing cylinder 4. The printing blanket 6 or the printing forme 6 has a cover layer 10, which in the exemplary embodiment shown consists of a printing layer 12 directed radially outward, a fabric layer 14 and a compressible layer 16. The topcoat may optionally contain additional layers. The cover layer 10 is connected to a support layer 18, which is preferably formed as a metal foil.

The leading end 20 and the trailing end 22 of the support layer 18 are free of the cover layer 10. By means of the ends 20 and 22, the blanket 6 and the

Compressor 6 is clamped in a manner known per se in the axially extending gap 8 of the impression cylinder 4. After clamping the blanket 6 and the

Printing form 6 on the printing cylinder 4 remains between the peripheral ends 24 and 26 of the cover layer 10, a channel 28 which extends in the axial direction of the printing cylinder 4. The channel 28 is completely filled with a compressible material 30.

Preferably, the filling of the channel 28 by means of the compressible material 30 is such that filling of the channel 28 in the radial direction is as thick as the cover layer 10 and the radially outward surface of the compressible material 30 with the radially outwardly facing surface of the print layer 12 forms a plane, as it is also shown in Fig. 1. The blanket 6 and the printing plate 6 then has the same thickness everywhere. This can be achieved, for example, in that the channel 28 is first filled to the extent that the compressible material 30 is beyond the pressure layer 12 and the excess compressible material 30 is abraded.

The compressible material 30 consists of a chemically curing material in which microspheres are embedded. Preferably, the chemically curing material 30 is a two-part epoxy resin. In the chemically curing material so many microspheres are embedded that the compressibility of the material 30 of the

Compressibility of the compressible layer 16 corresponds. It is possible to seal the edges of the circumferential ends 24, 26 of the cover layer 10 of the blanket 6 and the printing plate 6 with an elastomer prior to introducing the compressible material 30 into the gap 8. For a better connection of the compressible material to the edges of the peripheral ends 24, 26 is achieved.

Fig. 2 shows the system 2 with the gap 8, which is filled with the compressible material 30, in plan view. LIST OF REFERENCE NUMBERS

(Part of the description)

2 system

4 impression cylinders

6 blanket or printing form

8 gap

10 topcoat

12 printing layer

14 fabric layer

16 compressible layer

18 base course

20 leading end

22 trailing end

24 end

26 end

28 channel

30 compressible material

Claims

claims

System (2), consisting of:

- A printing cylinder (4) having a gap (8) in the axial direction,

- A blanket (6) or a printing plate (6) with a cover layer (10) containing a radially outwardly directed print layer (12), and with a support layer (18), wherein the leading end (20) and the trailing end (22) the support layer (18) is free of the cover layer (10),

wherein the leading end (20) and the trailing end (22) of the support layer (18) are clamped in the gap (8) of the impression cylinder (4) in a direction extending in the axial direction of the impression cylinder (4) channel (28) between the peripheral ends (24, 26) of the cover layer (10) remains,

characterized in that the channel (28) is completely filled with a compressible material.

System (2) according to claim 1, characterized in that the compressible material consists of a chemically hardening material embedded in the microspheres.

System (2) according to claim 2, characterized in that the cover layer (10) has a compressible intermediate layer (16) and that in the chemically curing material as many microspheres are embedded that the compressibility of the

Interlayer (16) corresponds to the compressibility of the chemically curing material.

System (2) according to one of claims 1 to 3, characterized in that the chemically curing material is an epoxy resin.

5. System (2) according to one of claims 1 to 4, characterized in that the

Supporting layer (18) is a metal foil. Method for producing a system (2) consisting of:

a printing cylinder (4) having a gap (8) in the axial direction,

a printing blanket (6) or a printing form (6) having a covering layer (10) which contains a printing layer (12) oriented radially outwards and a supporting layer (18), the leading end (20) and the trailing end (10) 22) of the support layer is free of the cover layer, and

wherein the leading end (20) and the trailing end (22) of the support layer (18) are clamped in the gap (8) of the impression cylinder (4) in such a way that in the axial direction of the impression cylinder (4) extending channel (28) between the peripheral ends (24, 26) of the cover layer (10) remains,

characterized in that the remaining channel (28) is completely filled with a compressible material.

A method according to claim 6, characterized in that the compressible material is formed as a two-component epoxy resin and that at least one

Component of the epoxy resin contains microspheres.

Method according to one of claims 6 to 7, characterized in that the end faces of the peripheral ends (24, 26) of the cover layer (10) are sealed prior to introducing the compressible material with an elastomer.