EP1871614B1 - Printing blanket for mounting on a rotating supporting cylinder of a printing machine - Google Patents

Abstract

The invention relates to a printing blanket for mounting on a rotating supporting cylinder of a printing machine. The printing blanket is in the form of a sheet whose ends are configured as leading edges and trailing edges that are adapted for being engaged in an axial fixing gap of the supporting cylinder. The blanket is characterized in that it has a multilayer structure consisting of film and reinforcing fibers. The invention can be used in the area of the printing machines.

Description

A printing blanket for mounting on a rotatable support cylinder of a sheet-like printing machine whose leading edge and trailing edge ends are configured to engage a axial fixing slot of the support cylinder.

Blankets of this type are already known which comprise a steel strip covered with an elastomer composite and folded at both ends to prepare the mounting on the support cylinder. These blankets have many drawbacks, such as their high cost due to their delicate manufacture combining a steel strip and an elastomer composite, adhesion difficulties and the fragility of the elastomer-steel connection, the delicate handling in that the Steel has a tendency to mark itself with fold formation, limitations on the size of the products due to the limitations of the widths of the rolling mills and the difficulties of disposal and recycling at the end of their life with separation of the layers. In addition, it has been found that the steel strip is mechanically aggressive towards the cylinder of the machine, which requires protection for example by a polyester film, and therefore additional handling and costs.

The invention aims to provide a blanket of the type defined above, which overcomes the disadvantages just stated.

To achieve this purpose, a blanket according to the invention is characterized in that it has a multilayer structure based on films and fibrous reinforcement.

According to a characteristic of the invention, the edge portion serving as fixing means in the slot of the support cylinder is a polyester or polycarbonate type film or equivalent associated with a unidirectional aramid or polyethylene type reinforcement embedded in a polymer matrix. or fiber reinforced polymers.

According to another characteristic of the invention, the part intended to be used as fixing means is formed by a polyester or polycarbonate type film associated with a reinforcement of woven or non-woven type with polyester fibers or aramid or polyamide or polyethylene or still metal embedded in a matrix of polymers.

According to yet another characteristic of the invention, the blanket fixing part is formed by a combination of two films of identical or different nature comprising a polymer intermediate layer forming a box.

According to yet another characteristic of the invention, the blanket fixing portion is formed by a combination of two films of identical or different nature comprising a polymer intermediate layer associated with unidirectional reinforcements of aramid or polyethylene type or reinforced with fibers.

According to yet another characteristic of the invention, the blanket fixing part is formed by a combination of two films comprising a compressible intermediate layer forming a box.

According to yet another characteristic of the invention, the blanket fixing part is formed by a combination of two films comprising a compressible intermediate layer associated with unidirectional reinforcements of aramid or polyethylene type forming a box.

• la figure 1 est une vue en coupe, avec arrachement, d'un blanchet monté sur un cylindre de support ;
• les figures 2 et 3 illustrent deux modes de configuration d'un blanchet selon l'invention ;
• les figures 4 à 14 sont des vues en coupe illustrant schématiquement plusieurs modes de réalisation d'un blanchet selon l'invention.

The invention will be better understood, and other purposes, features, details and advantages thereof will become clearer in the course of the explanatory description which follows, with reference to the appended schematic drawings given solely by way of example and illustrating several embodiments of the invention and in which:

• the figure 1 is a sectional view, cut away, of a blanket mounted on a support cylinder;
• the Figures 2 and 3 illustrate two modes of configuration of a blanket according to the invention;
• the Figures 4 to 14 are cross-sectional views schematically illustrating several embodiments of a blanket according to the invention.

As shown in figure 1 , the invention relates to a blanket designated by reference numeral 1 which is mounted on a support cylinder 2, in a manner known per se by engaging its ends configured in leading edges 3 and leakage 4 in an axial slot 6 formed in the cylinder 2. The leading and trailing edges are fixed in this slot 6 with the aid of a device 8 whose general structure is known and therefore does not need to be described in more detail. It is sufficient to indicate for the understanding of the invention that this device comprises a rotating cylindrical member 9 placed in a recess 10 of complementary shape in the cylinder 2, which opens at its periphery in the slot 6 so that, in the angular position of the member 9 shown on the figure 1 , a pressing element 11 which is radially movable in a radial passage 10 of the member 9 can be brought into its illustrated position in which its outer end 12 ensures the fixing of the leading and trailing edges of the blanket in the slot 6 in pressing its ends against the opposite inner face of the slot 6.

As we see specifically on Figures 2 and 3 , a blanket according to the invention has a multilayer structure which is thinned at its ends to form the leading edges 3 and trailing 4, the non-thinned portion then constituting the printing portion of the blanket, which is designated by the reference 15. The blanket is obtained by cutting the desired format of a sheet having the multilayer structure as seen in 15 on the figures 2 and 13 and by appropriate machining of the ends for the formation of the leading edges 3 and leakage 4.

We see, which is confirmed by the Figures 4 to 12 illustrating a multitude of embodiments of a blanket according to the invention, the portion 15 has above the layers which constitute at their ends the leading and trailing edges an upper and outer printing layer 17, a layer of fabric 18 and a compressible layer 19. The Figures 2 and 3 show that a protective layer 14 can be added to the face opposite the printer surface, beneath the layers of the leading and trailing edges, to mechanically protect the machine cylinder and the fastening layers and to fill, where appropriate, the space. The protective layer 14 may optionally be made compressible to increase the shock absorption capacity of the blanket 1. The protective layer 14 could be removed at the leading edges 3 and leakage 4.

The leading and trailing edges could have the same thickness and the same structure, in accordance with the figure 2 , but it could be advantageous to provide an asymmetry between the geometries of the leading edges 3 and leakage 4. Since the leading edge 3 is, in principle, more stressed, it could be thicker or reinforced by any means known per se with respect to the trailing edge 4 which could be thinned, which further reduces the area of the groove 13 and generating vibrations.

The multilayer structure of the blanket is manufactured according to traditional technologies based on thermo-labeled or polymer-based elastomers with associated processes as described in French Patent Application Nos. 2,809,667 and 2,809,665 .

A blanket according to the invention comprises at least one printing layer, a compressible layer and a base for fixing the blanket on the cylinder and which is formed by the combination of a film layer with at least one second film fixed by means of a polymer layer, a reinforcement embedded in a polymer matrix for the purpose of forming a box or a foldable composite structure having a plastic behavior and a shape memory. For the manufacture of the web, it will be advantageous to use calendering or extrusion processes, and then assembly of the different layers.

Referring to Figures 4 to 14 Hereinafter, a number of exemplary embodiments of the multilayer structure of a blanket according to the invention will be described below.

In the example shown on the figure 4 , the multilayer blanket successively has from outside to inside, an outer printing layer 17, a fabric layer 18, a compressible layer 19, a polyester or polycarbonate type film 20, a reinforcement 21 of the type unidirectional aramid or polyethylene embedded in a polymer filling matrix layer, this layer being able to be made of a rectifiable material so that its free inner face 22 intended to come into contact with the peripheral face of the support cylinder 2 can be rectified after the constitution of the multilayer structure to standardize the thickness of the multilayer web, which will then be cut to the desired format.

In the embodiment according to the figure 5 , the blanket comprises successively, from the outside to the inside, as in the case of the figure 4 , an outer printing layer 17, a fabric 18 and a compressible layer 19, then a film 24 of polyester or polycarbonate type, a unidirectional reinforcement 25 of aramid or polyester type embedded in a filling layer 26 in expanded polymer and / or containing fibers, the inner face can be rectifiable.

In the example shown on the figure 6 the blanket comprises, as in the first cases, an outer printing layer 17, a fabric 18 and a compressible layer 19 and then, embedded, in a filling layer 28 of expanded polymer or / and containing fibers, a reinforcement unidirectional 29 of aramid or polyester type, and finally a film 30 of polyester or polycarbonate type.

The figure 7 shows an exemplary embodiment of the blanket 1, which comprises successively a printing layer 17, a fabric layer 18, a compressible layer 19, a film 32 of polyester or polycarbonate No. 1, a unidirectional reinforcement 32 of aramid type or polyester embedded in a filler layer 33 made of expanded polymer and / or containing fibers, and an outer film of polyester or polycarbonate type No. 2.

The embodiment of the blanket according to the invention, illustrated on the figure 8 , comprises, following the printer layers 17, fabric 18 and compressible 19, a film 37 of polyester or polycarbonate No. 1 type, filling 38 expanded or unexpanded polymer and containing fibers and a film 9 of polyester or polycarbonate type # 2.

In the embodiment according to the figure 9 the blanket comprises a printer layer 17, a fabric 18, a compressible layer 19, a film 41 of the polyester or polycarbonate type No. 1, a unidirectional reinforcement 42 of aramid or polyester type embedded in a polymer filling layer 43 as well as a film 44 of polyester or polycarbonate type No. 2.

The example shown on the figure 10 comprises, as the examples above, an outer printing layer 17, a fabric 18 and a compressible layer 19 and then, specific to this example, a film 46 of polyester or polycarbonate type No. 1, a unidirectional reinforcement 47 of aramid or polyester type, embedded in a filling layer 48 of expanded or unexpanded polymer, and / or containing fibers, a film 49 of polyester or polycarbonate type No. 2 and a filler layer 50 of expanded or unexpanded polymer.

The figure 11 shows an example which comprises, as those mentioned above, on the outside a printing layer 17, a fabric 18 and a compressible layer 19 and, subsequently, a film 52 of polyester or polycarbonate type No. 1, a layer filling member 53 made of expanded or unexpanded polymer and containing fibers, a film 54 of polyester or polycarbonate type No. 2 and a filling layer 55 of expanded or unexpanded polymer, this polymer being rectifiable so that its internal face can be rectified to ensure a uniform thickness of the blanket.

The figure 12 shows yet another embodiment of a blanket according to the invention, which comprises an outer printing layer 17, a fabric 18, a compressible layer 19, a layer 57 of unidirectional reinforcement N ° 1 aramid or polyester, etc. positioned perpendicularly to the unidirectional reinforcement No. 2, an unidirectional reinforcement 58 of aramid or polyester No. 2, a filling layer 59 of expanded or unexpanded polymer, and / or containing fibers, a film 60 of polyester or polycarbonate type. and a filler layer 61 made of expanded or unexpanded polymer and whose free face is rectified, optionally.

The figure 13 shows yet another embodiment of a blanket according to the invention, which comprises, specifically, following the three outer printing layers 17, fabric 18 and compressible 19, a reinforcement 63 unidirectional No. 1 aramid or polyester, etc., arranged perpendicularly to the unidirectional reinforcement No. 2, a film 64 of the polyester or polycarbonate type, a unidirectional reinforcement 65 aramid or polyester and a filler layer 66 of expanded or unexpanded polymer and / or containing fibers, whose free face can be rectifiable.

Finally, figure 14 illustrates an exemplary embodiment of a blanket according to the invention, which comprises, beneath the printing portion formed by the printer layer 17, the fabric 18 and the compressible layer 19, a unidirectional reinforcement No. 1 aramid or polyester, with the reference 68, integrated in a filler layer 69 of expanded or unexpanded polymer and / or containing fibers, a non-directional reinforcement 70 of aramid or polyester No. 2 embedded in a filler layer 71 of expanded or non-expanded polymer expanded or / and containing fibers, the free face of the latter layer being optionally rectified.

It is apparent from the descriptions of the numerous examples of embodiment of a blanket according to the invention, that the function filled, in the case of known blankets, by a single strip, is accomplished in the case of the invention by a multilayer structure based on of films and fibrous reinforcements, which eliminates the problems inherent in the blankets used until now. With regard to the multilayer structure, it has furthermore been found that a simple film known per se of thickness similar to the known metal strip would not constitute a satisfactory solution to the problem which is at the basis of the invention. on the one hand because of the insufficient mechanical strength, and on the other hand, because of the absence of shape memory making assembly difficult, if not impossible in practice. Regarding the mechanical strength, a blanket must work for months without risk of loss of integrity to ensure the safe operation of the presses. However, a thin film alone, of thickness similar to steel, that is to say from 0.2 to 0.3 mm, is not strong enough in itself and a Thicker film would become brittle in the crease zone with cracking and fracture initiation.

The multilayer blankets proposed by the invention, on the other hand, make it possible to retain the capacity to be folded by a thin strip, to provide an increased mechanical safety by adding material and to keep its shape memory without generating structural weaknesses in the zone of fold.

• un film de type polyester ou polycarbonate ou équivalent associé à un renfort de type aramide ou polyéthylène unidirectionnel noyé dans une matrice de polymère ou de polymère renforcé par des fibres ;
• un film de type polyester ou polycarbonate associé à un renfort de type tissé ou non-tissé à fibres polyester ou aramide ou polyamide ou polyéthylène ou encore en métal noyé dans une matrice de polymère ;
• une association de deux films de nature identique ou différente comportant une couche intermédiaire en polymère formant un caisson ;
• une association de deux films de nature identique ou différente comportant une couche intermédiaire en polymère associée à des renforts unidirectionnels de type aramide ou polyéthylène ou encore renforcé par des fibres ;
• une association de deux films comportant une couche intermédiaire compressible formant un caisson ;
• une association de deux films comportant une couche intermédiaire compressible associée à des renforts unidirectionnels de type aramide ou polyéthylène formant un caisson.

It can be seen from the various examples of implementation of the invention that the portion of the blanket intended to be used as fixing means to replace the known steel strip, that is to say the leading and trailing edges can to include:

• a polyester or polycarbonate type film or equivalent associated with a unidirectional aramid or polyethylene type reinforcement embedded in a matrix of polymer or polymer reinforced with fibers;
• a polyester or polycarbonate type film associated with a reinforcement of woven or non-woven type with polyester or aramid fibers or polyamide or polyethylene or metal embedded in a polymer matrix;
• a combination of two films of identical or different nature comprising a polymer intermediate layer forming a box;
• a combination of two films of identical or different nature comprising a polymer intermediate layer associated with unidirectional reinforcements of aramid or polyethylene type or reinforced with fibers;
• an association of two films comprising a compressible intermediate layer forming a box;
• a combination of two films comprising a compressible intermediate layer associated with unidirectional reinforcements aramid type or polyethylene forming a box.

The order of the layers is irrelevant and could be the subject of an optimization choice. A layer of protection on the opposite side to the printer side can be added to mechanically protect the machine cylinder and the fixing layers and fill the space if necessary. It should be noted that the reinforcement is, preferably, embedded between two films and embedded in a polymer matrix.

It is advantageous to bend the blanket in the hot state to help shape and keep shape memory thereof after bending and cooling. The bending can be performed by machines known per se already used to bend the offset plates. In these machines, the leading and trailing edge blankets are successively introduced into a slot adapted to a mechanical stop. The machine automatically bends the blanket held in position by the operator. Two types of bending are considered depending on whether it is the leading edge or the trailing edge.

It should also be noted that the filling polymer or the polymer matrix to be used in the context of the invention could usefully have a glass transition temperature greater than ambient temperature to help shape memory in case of bending of the ends. hot. As shown in figure 2 it may be advantageous to provide an asymmetry between the geometries of the leading and trailing edges. The leading edge which is more stressed could be thicker and reinforced by any known means in relation to the trailing edge which could be thinner, the aim being to further reduce the area of the non-printer groove and generating vibrations .

By way of example, the total thickness of a blanket according to the invention could be between 1.00 mm and 3.30 mm, the thicknesses of the films envisaged between 50 microns and 250 microns, the thicknesses of the polymer layers of bond between 0.10 and 0.5 mm and the thicknesses of the fixing zones according to the invention between 0.25 and 0.70 mm.

Regarding the nature of the materials, the films could be polyester, polybutylene terephthalate (PBT), polycarbonate, and polypropylene. As a polymer, it would be advantageous to use thermoplastic material such as polyurethane (TPU), polyesters, polyethylene, extruded elastomers, elastomers extruded and reinforced with short fibers or polyamides. With regard to fibers, it is advantageous to use polyester, aramid, polyamide, polyethylene, glass, carbon or steel fibers. As an associated blanket, it is advantageous to use traditional rubber with a compressible layer of fabric reinforcement and polymer technology.

Claims (13)

1. Printing blanket for mounting on a rotary support cylinder of a printing machine, having a multilayer structure based on films and fibrous reinforcements defining a sheet forme the edges whereof configured as leading and trailing edges are adapted to be engaged in an axial fixing slot of the support cylinder, the trailing and leading edges having a smaller thickness than the printing part (15) of blanket, the multilayer structure of the blanket (1) including, from the exterior toward the interior, successively, a multilayer part including an exterior printing layer (17) that is eliminated at the leading edge (3) and the trailing edge (4) and an underlying fixing part the edges of which constitute at least the leading edge (3) and the trailing edge (4), characterised in that the underlying fixing part has a multilayer structure.
2. Blanket according to claim 1, characterised in that it includes under the multilayer part the edges of which constitute the leading edge (3) and the trailing edge (4) a protection layer (14) in contact with the exterior surface of the support cylinder (2).
3. Blanket according to claim 2, characterised in that the protection layer (14) is eliminated at the leading edge (3) and the trailing edge (4).
4. Blanket according to any one of claims 1 to 3, characterised in that the leading edge (3) and the trailing edge (4) have the same multilayer structure.
5. Blanket according to any one of claims 1 to 3, characterised in that the trailing edge (4) is thinner than the leading edge (3).
6. Blanket according to any one of claims 1 to 5, characterised in that the multilayer part of the leading edge (3) and the trailing edge (4) includes a film such as a polyester or polycarbonate type film associated with a unidirectional polythene or aramide type reinforcement embedded in a polymer or fibre-reinforced polymer matrix.
7. Blanket according to any one of claims 1 to 5, characterised in that the multilayer part of the trailing edge (4) and the leading edge (3) includes a film such as a polyester or polycarbonate type film associated with a woven or non-woven type reinforcement with polyester or aramide or polyamide or polyethylene fibres or in metal buried in a polymer matrix.
8. Blanket according to any one of claims 1 to 5, characterised in that the multilayer part of the leading edge and the trailing edge includes a combination of two films, where appropriate identical, including an intermediate polymer layer forming a cushion.
9. Blanket according to any one of claims 1 to 5, characterised in that the multilayer part of the leading edge (3) and the trailing edge (4) includes a combination of two films, where appropriate identical, including a polyester intermediate layer combined with aramide or polyethylene type or fibre-reinforced unidirectional reinforcements.
10. Blanket according to any one of claims 1 to 5, characterised in that the multilayer part of the leading edge (3) and the trailing edge (4) includes a combination of two films including a compressible intermediate layer forming a cushion.
11. Blanket according to any one of claims 1 to 5, characterised in that the multilayer part of the leading edge (3) and the trailing edge (4) includes a combination of two films and, between the two films, a compressible intermediate layer combined with aramide or polyethylene type unidirectional reinforcements forming a cushion.
12. Blanket according to any one of claims 1 to 11, characterised in that its multilayer structure is produced in the form of a sheet and cut to the required format and the leading and trailing edges are obtained by appropriate machining of the edges of the blanket cut to the format.
13. Blanket according to any one of claims 1 to 11, characterised in that it includes a backing layer produced in a polymer material that can be precision ground and in that this backing layer has been precision ground to render the thickness of the blanket uniform.

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