EP0955160A2 - Process for the fabrication of a sleeve , especially for the printing industrie - Google Patents

Abstract

The core roll (1) is coated with release agent and the non-elastic tube (20) is drawn over the core leaving a gap between them. After centering the tube on the roll an elastic compressible material (60,65) is injected between them and cured. Preferred Features: The gap is vented during injection through sealable vents (50) which are closed immediately the gap is filled and further material is then injected to compress the material in the gap. The vents and/or injectors (40) are located in the tube centering device (30).

Description

The invention relates to a method for producing a sleeve, in particular for the printing industry, with an essentially inelastic outer jacket and an elastic and compressible inner jacket, in which the sleeve is produced on a production roll core.

For sleeves, especially in the field of rotary printing forms in the printing industry, metallic cylinders are mainly used, on the surface of which a functional profile is created. Steel rollers are usually galvanically coated with a copper layer, into which the functional profile is then introduced. Furthermore, nickel sleeves are also known, which are also produced galvanically.

The sleeves can be used, for example, as gravure, flexographic or embossed sleeves.

A pneumatic method is preferably used for removing or re-installing sleeves on a roller core. For this purpose, an inner jacket or an expansion layer made of an elastic and compressible material is arranged on the inside of the sleeve. This inner jacket or the expansion layer between the roller core and the outer jacket of the sleeve is necessary because the sleeve must not be damaged by excessive pressures when being pulled on or pulled off, and the pressure of the pneumatic means, which is generally caused by radial passages in which the roller core is pressed between the outer shell of the roller core and the inner shell of the sleeve must act on the entire surface in order to enable problem-free removal of the sleeve. Furthermore, the inner jacket or the expansion layer has the task of compensating for unevenness on the inside of a tubular sleeve.

The connection of the sleeve to the carrier core, which can be made of steel or plastic, for example, can be carried out by means of frictional engagement or positive engagement, the sleeve being produced in the frictional connection on a core which has a slightly smaller diameter than the later carrier core.

Methods are known in which a release agent is first applied to the roll core, on which the expansion layer is then built up. After the expansion layer has dried, its surface must be treated and / or ground down before the outer jacket of the sleeve can be applied in a further step. Such a method is very complex, in particular because it is necessary to wait for the expansion layer to harden before the further construction of the sleeve can take place. Furthermore, the step of processing the expansion layer after it has hardened, e.g. grinding, very time consuming.

It is therefore the object of the present invention to provide a method for producing a sleeve with a substantially inelastic outer jacket and an elastic and compressible inner jacket, which minimizes the necessary process steps and in particular time delays between the individual process steps, for example due to curing times etc. to avoid.

This object is achieved by a method according to claim 1, preferred embodiments are the subject of the dependent claims.

The method according to the invention accordingly comprises the steps of coating the roll core with a release agent, pulling an essentially inelastic tube onto the production roll core, the tube having an inside diameter which is larger than the outside diameter of the production roll core, so that an intermediate space is formed between them, centering the Pipe on the production roll core, so that there is a substantially equal distance between the pipe and the production roll core, injection of a mass forming the elastic and compressible inner jacket into the space between the pipe and the production roll core and hardening of the injected mass.

As a result, in a single process step, the expansion layer or the inner jacket of the sleeve is formed and at the same time a connection is made to the outer jacket of the sleeve, an essentially inelastic tube. In addition to the significant simplification of the process sequence, problems with the connection of the inner jacket and the outer jacket are also avoided, since the inner jacket or the expansion layer can be connected directly to the thermoplastic or metallic tube during injection.

The expansion layer can also harden after completion of all necessary process steps, so that there is no need to wait for sufficient hardening between the individual process steps. As a result, the manufacturing process is accelerated, in particular the efficiency of the machines used is improved, since in a method according to the invention no special machine park is necessary during the curing.

It is preferably provided that the space between the tube and the production roll core is vented by venting devices during the injection of the mass forming the inner jacket. These venting devices are preferably closable and are closed as soon as the cavity between the tube and the production roll core is completely filled with the mass forming the inner jacket. On the one hand, this ensures a controlled and trouble-free ventilation of the intermediate space, and the mass forming the inner jacket is prevented from escaping from the intermediate space and the possibility is created of compressing the mass in the intermediate space as desired.

In a preferred embodiment, the injection of the mass forming the inner jacket takes place on one side of the space between the production roller core and the tube, while the ventilation is carried out on the opposite side, in the direction of the longitudinal axis of the roller core, which enables and prevents particularly controlled ventilation. that unwanted air pockets remain in the expansion layer or in the inner jacket.

It is particularly preferred that the above-mentioned ventilation devices and / or injection devices are arranged in a centering device, which the tube in one maintains predetermined, uniform distance from the manufacturing roll core. The compact structure provided thereby simplifies the method, and errors due to the interaction of several components can be largely avoided.

The finished sleeve is preferably removed pneumatically by pressing a liquid or gaseous medium into the roll core and exerting pressure on the sleeve through radial bores in the lateral surface of the production roll core. As a result, the finished sleeve can be pulled off the production roll core without higher pressures or frictional forces occurring which lead to damage to the inner jacket or the expansion layer.

In a further embodiment, the inside of the inner jacket is formed with a structure by a structured surface of the production roll core. This ensures a positive connection between the finished sleeve and a carrier core. Such a positive connection can be desirable, in particular when high forces are to be expected, in order to provide an increased holding force compared to the frictional connection.

The production roller core preferably consists of metallic materials, in particular aluminum or steel. However, depending on the requirements, other materials can also be used for the production roller core, these are selected in particular for their durability or durability, but also for their weight.

Closed-cell foams, into which additional air bubbles and / or expanded polystyrene beads can be introduced, are particularly suitable as an elastic and compressible mass for the inner jacket. Such a material shows excellent elasticity and compression values, while at the same time ensuring a secure connection between the inner jacket and the outer jacket of the sleeve. The processing of these foams is also very unproblematic.

Furthermore, particles can be introduced into the mass forming the inner jacket in order to make the inner jacket electrically conductive.

In a further embodiment, the inner jacket consists of two or more layers. Such a multilayer structure leads to a higher flexibility of adaptation of the sleeve to the desired task, so that the more complex manufacturing process is accepted.

A functional profile for later use, in particular in rotary printing, is preferably introduced onto the outer jacket, and further coatings can also be applied to the outer jacket. These further coatings are particularly preferably made of polyurethane (PU), polytetrate fluoroethylene (PTFE) or copper and allow problem-free incorporation of a functional profile and also fulfill a protective function for the layers of the sleeve underneath.

Both the materials for the outer jacket, preferably metallic or thermoplastic material, and the materials of any further coatings are selected and in particular with regard to the desired method for applying a functional profile, such as, for example, direct structuring by means of a laser beam or removal from an ionized state customized.

In a further embodiment it is provided that a functional layer is additionally glued on, as a result of which the usual manufacturing step of attaching a functional profile, for example by means of direct structuring by means of a laser beam or by removal from the ionized state, is significantly simplified.

The functional layer can also be a wear protection layer, for example.

Functional profile should also be understood to mean openings, bores and the like through the sleeve. It is also possible to subsequently provide the sleeve with perforations in the manner of a sieve. Such a sleeve can then be used, for example, as a rotary sieve for sieving bulk goods or as a suction cylinder, for example for sucking in foils or for removing water from paper.

Thanks to the flexible design of the surface, it can also be used as a textile printing template.

In a further embodiment, the production roller core has a conical shape, which in particular simplifies the pneumatic mounting or removal of the sleeve from the roller core. Such a conical course can also be desirable for later use depending on the area of application.

In a further preferred embodiment, the production roller core is used directly as a carrier core for the use of the manufactured sleeve. This eliminates the step of pulling off the sleeve, which likewise leads to a simplified processing process and to an immediate introduction of the manufactured sleeve into the manufacturing process.

In principle, all known methods can be used for applying a wide variety of surfaces or layers to the sleeve. These include in particular spraying processes, thermal spraying, fluidized bed sintering, vulcanizing rubber, pouring on or applying shrink sleeves etc.

All known methods can also be used for structuring the sleeve. These include, in particular, the laser direct structuring already mentioned, which can be variable both in terms of area and depth, the abovementioned removal from the ionized state or mechanical engraving, etc.

The method according to the invention is explained in more detail with reference to the attached FIG. 1, which shows a cross section through an embodiment of a system which produces a sleeve according to the method according to the invention.

In Figure 1, a roll core 1 is shown, which has a compressed air connection 2, through which compressed air is pressed as one of the possible liquid or gaseous media in the roll core, and a radial bore 3 in the outer jacket of the roll core 1, through which the compressed air between the Inner jacket or the expansion layer 60, 65 and the manufacturing roll core 1 is pressed for pneumatic removal or mounting of the sleeve.

A thermoplastic tube 20 is used here as the inelastic tube, which is kept at a uniform distance from the production roll core 1 by means of centering devices 30.

Depending on the application, the methods for applying the surfaces or layers can be selected or used in combination.

In the centering devices 30 injection nozzles 40 are formed on the one hand, which are directly connected to the space between the thermoplastic tube 20 and the roller core 1, and on the other hand ventilation nozzles 50 on the opposite side of the space, so that a controlled ventilation of the space during the injection of the the inner jacket 60, 65 forming material is guaranteed.

In FIG. 1, the inner jacket or the expansion layer 60, 65 has already been injected, the expansion layer being an elastomeric matrix 60 into which expanded polystyrene beads 65 have been introduced.

The features of the invention disclosed in the above description, in the drawing and in the claims can be essential for realizing the invention both individually and in any combination.

Claims (23)

Method for producing a sleeve, in particular for the printing industry, with an essentially inelastic outer jacket (20) and an elastic and compressible inner jacket (60, 65), in which the sleeve is produced on a production roll core (1),
characterized in that the method comprises the following steps: Coating the roller core (1) with a release agent, - Pulling a substantially inelastic tube (20) on the production roll core (1), the tube (20) having an inner diameter which is larger than the outer diameter of the production roll core (1), so that a space is created between them; - Centering the tube (20) on the production roll core (1) so that there is an essentially equal distance between the tube (20) and the production roll core (1); - Injection of a mass (60, 65) forming the elastic and compressible inner jacket into the space between the tube (20) and the production roller core (1) and - curing the injected mass (60, 65). A method according to claim 1, characterized in that the space between the tube (20) and the production roll core (1) during the injection of the inner jacket forming mass (60,65) is vented by closable venting devices (50). A method according to claim 2, characterized in that the ventilation devices (50) are closed as soon as the cavity between the tube (20) and the production roll core (1) is completely filled with the mass (60, 65) forming the inner jacket. Method according to Claim 2 or 3, characterized in that after the ventilation devices (50) have been closed, the mass (60, 65) forming the inner jacket is further injected in order to compress the mass (60, 65) in the intermediate space. Method according to one of the preceding claims, characterized in that the injection takes place on one side of the intermediate space between the production roll core (1) and the tube (20), while the ventilation is carried out on the opposite side. Method according to one of claims 2 to 5, characterized in that the ventilation devices (50) and / or injection devices (40) are arranged in a centering device (30) for the pipe (20). Method according to one of the preceding claims, characterized in that the removal of the finished sleeve is carried out pneumatically, preferably by means of compressed air. Method according to one of the preceding claims, characterized in that, to remove the sleeve, a liquid or gaseous medium is pressed through a connection (2) into the roll core (1) and pressure is applied through radial bores (3) in the lateral surface of the production roll core (1) exerts on the sleeve. Method according to one of the preceding claims, characterized in that the inside of the inner casing is formed with a structure by a structured surface of the production roller core (1). Method according to one of the preceding claims, characterized in that the production roller core (1) consists of metallic materials, in particular aluminum or steel. Method according to one of the preceding claims, characterized in that closed-cell foams are used as the mass (60, 65) for the inner jacket. Method according to one of the preceding claims, characterized in that air bubbles and / or expanded polystyrene beads (65) are additionally introduced into the mass (60) forming the inner jacket. Method according to one of the preceding claims,
characterized in that particles are additionally introduced into the mass (60, 65) forming the inner jacket, which make the inner jacket conductive. Method according to one of the preceding claims, characterized in that the inner jacket consists of two or more layers. Method according to one of the preceding claims, characterized in that the substantially inelastic tube (20) consists of a metallic or a thermoplastic material. Method according to one of the preceding claims, characterized in that a functional profile is introduced onto the outer jacket (20). A method according to claim 16, characterized in that the functional profile is introduced by direct structuring which is variable in area and / or depth with a laser beam and / or by removal from an ionized state and / or by mechanical engraving. Method according to one of the preceding claims, characterized in that additional coatings are additionally applied to the outer jacket (20). A method according to claim 18, characterized in that the additional coatings consist of polyurethane (PU), polytetrate fluorethylene (PTFE) or copper. Method according to claim 18 or 19, characterized in that the coatings are applied by means of a spraying process, thermal spraying, fluidized bed sintering, pouring on or by using shrink sleeves. Method according to claim 18, characterized in that a functional layer is additionally glued on. Method according to one of the preceding claims, characterized in that the production roll core (1) has a conical course. Method according to one of the preceding claims, characterized in that the production roller core (1) is used as a carrier core for the use of the manufactured sleeve.

Images