EP1224078B1 - Surface in the form of a sleeve and a method for mounting same - Google Patents

Abstract

The invention relates to a sleeve for the printing industry. The inventive sleeve has a flexible surface which is provided with the printing pattern. The sleeve can be mounted on a cylindrical support body. The surface is configured in a tubular manner and is provided with two front faces. The inner diameter of the surface is smaller than the outer diameter of the support body when the surface is removed from the support body. According to the invention, the surface is designed like a flexible tube in such a way that the surface can be expanded by means of compressed air that is blown against the outside of the front face pertaining to the surface, whereby said front face has to be slid on the support body. The sleeve can thus be completely mounted on the support cylinder. The aim of the invention is to mount such a sleeve. Compressed air is blown from the outside between the flexible surface and the support body by means of an outlet valve. The compressed air is directed against the front face of the surface from the outside and against the slide-on direction of the surface, whereby said front face is slid on the support body.

Description

The invention relates to a sleeve according to the preamble of claim 1 and a method for mounting such sleeves.

A generic sleeve is known from EP 0,753,496 A1 for the field of flexographic printing. The sleeve is pushed onto a carrier body by an air cushion between the sleeve and the carrier body is generated. The carrier body is designed as a so-called air cylinder, with air outlet openings on its surface.

The surface having the print motif of the generic sleeve is provided in the form of a rubber layer, in which the print motif can be engraved.

The surface of the generic sleeve having the print motif is merely the outer part or the outer layer of an overall multi-layered sleeve, since it is vulcanized onto an inner layer, that is to say firmly connected to it. This inner layer consists of a fiber-reinforced plastic and should expressly have a correspondingly high strength and rigidity. Thus, the entire sleeve is relatively stiff, in the context of the required, the flexoprint typical assembly and disassembly enabling flexibility.

For fixed clamping fit of the sleeve on the carrier body, the inner layer has an inner diameter which is smaller than the outer diameter of the carrier body. Due to the wall thickness of the inner layer results in an inner diameter of the outer, the surface-forming layer of the sleeve, which is greater than the outer diameter of the carrier body. Without the inner layer is the surface having the print motif the generic sleeve can not be mounted on the carrier body.

From the practice of flexographic printing non-generic, also relatively stiff, multi-layer sleeves are known whose flexible surfaces do not have the print motif, but serve as a damping intermediate layer. On this layer comparatively hard printing plates, which in turn have the print motifs are glued.

In all the above cases, the surfaces are firmly connected to the actual flexographic printing sleeve. All surfaces wear out during the printing process, become tired or damaged during the handling of the sleeves, so that they have to be renewed. For surfaces having the print motif, a premature renewal may also be required if the print motif is to be replaced by another one.

A renewal of the surfaces is very expensive and associated with longer downtime of the sleeve for the printing operation, such downtime often can not be accepted for economic reasons. As a result, worn or damaged printing sleeves are often disposed of altogether and new replacement sleeves are procured.

The aforementioned generic, known from EP 753 416 A1 known sleeve is designed in two parts, with a sleeve core which is mounted directly on the support cylinder, and with a separate outer sleeve, which contains the surface having the print motif. Although the bipartite requires initially a cumbersome installation, since both sleeve parts are mounted on the usual flexographic printing principle, but it allows the replacement of the outer sleeve with the surface. Thus, a comparatively simple and inexpensive change of print motifs is made possible by only the relatively inexpensive, thin-walled outer sleeves must be replaced with the print motifs, while the wall thickness of the overall sleeve decisively determining sleeve core can remain on the air cylinder. However, the sleeve cores are usually at least twice as expensive as a comparably large, one-piece sleeve without air flow due to the required air ducts.

The advantages of flexographic printing can only be achieved with carrier cylinders having such air outlet openings. In the two-part sleeves mentioned, therefore, not only the actual carrier cylinder, but also the inner sleeve core must have such air outlet openings to allow the assembly of the outer sleeve, which has the surface with the print motif.

From DE 43, 42, 159 A1 a generic foreign sleeve for the field of offset printing is known. In this case, a sleeve-shaped printing plate is used, which is formed from an aluminum plate, because aluminum is given as a common material in offset printing. As in flexographic printing, the carrier cylinder has radially outwardly opening compressed air openings, which should create an air cushion for the sleeve to be mounted or disassembled. In addition, a chamfer is provided as Aufschieberampe due to the relatively stiff sleeve material used, which is to protect the edge of the support cylinder from wear by the relatively rigid sleeve. The material, which is verdet in the range of this bevel, should differ from that of the rest of the carrier cylinder in terms of wear and compression resistance. Both the aluminum sleeve and the carrier cylinder with the required, special slide-on chamfer is comparatively expensive.

The invention has for its object to improve a generic flexographic printing sleeve to the effect that this mounted with the least possible time and financial cost as well as renewed or can be repaired. Furthermore, the invention has for its object to provide a method for assembling such a sleeve.

This object of the invention is achieved by a sleeve having the features of claim 1 and by a method with the method steps of claim 4.

Advantageous embodiments of the invention are the dependent claims.

In other words, the invention proposes to use the surface having the print motif as its own sleeve.

In departure from the previous manufacturing process, the flexible surface is not firmly anchored to the actual, relatively stiff sleeve, but the surface itself is configured as a separate, user-to-handle component as a hose, airtight and with a high degree of flexibility. In this way, the same carrier body for different motifs and applications can be used very inexpensively by mounting surfaces with different materials on this carrier body. It therefore results for the user, so for the printing company, a significant Savings compared to the purchase of several complete printing sleeves to allow the same variation.

While in the known flexographic printing sleeves, the inner surface of a sleeve is designed as slippery as possible to allow easy sliding, supported by an air cushion on the support cylinder or - in two-part sleeves - on the sleeve core, the invention provides the inner surface of the top auszuschaub fringful as possible in order to allow in this way a secure hold of the upper surface on the sleeve core.

The flexibility of the surfaces according to the invention is so great that they require no compressed air supply from the inside. Rather, it is sufficient to blow the front end of the surface with compressed air from the outside, which is pushed onto the carrier body. Therefore, the surfaces are also used on support bodies, which are designed without air ducts and are not intended for flexographic printing, so that even on older support bodies, the advantages of flexographic printing can be used.

However, the surfaces according to the invention can also be used on carrier cylinders, which are provided with air channels for flexographic printing. Possibly. must be used only with reduced air pressure when pushing the surfaces to avoid damage to the surfaces, which are softer and more flexible compared to the flexo-typical sleeves.

Even compared to the known flexographic printing sleeve system, the surfaces designed according to the invention offer advantages: The disposal costs and the costs for a replacement procurement with damaged motif surfaces are considerably reduced by the merely replaceable, exchangeable surfaces compared to the usual exchange of complete sleeves or the requisite milling and re-coating the surfaces. Instead, according to the invention, a motif change can be made just as quickly on a sleeve as a conventional sleeve change on a carrier cylinder.

It is known from two-part configured flexographic printing sleeves, to arrange an intermediate component on the carrier body, which is referred to as an intermediate sleeve, adapter sleeve or sleeve core, and raise a further sleeve with the surface having the print motif on this intermediate component. Also according to the invention, an intermediate component may be provided between the surface and the carrier body, the inventive separate surface being designed as a separate component which can be dismantled by this intermediate component.

For the present invention, this intermediate component represents the outer component of a two-part carrier cylinder and not the inner part or core of the sleeve. The inner diameter of the separate surface is therefore not smaller than the outer diameter of the actual carrier cylinder, but only smaller than the outer diameter of this intermediate component. In this case - unlike the usual two-piece sleeves - the same carrier cylinder can be used with the same intermediate component for different motif sizes by surfaces with different outer diameters are mounted on this two-piece carrier cylinder, ie on the intermediate component.

Unless otherwise stated, the term "carrier body" used below may include both known from the flexographic printing, one-piece air cylinder and the aforementioned two-part air cylinder, which are provided with an intermediate component, as well as for flexographic printing initially not provided carrier cylinder without air flow.

If the carrier body has flexo-pressure-suitable air ducts, these air ducts can continue to be used. In the case of two-part carrier bodies, the air ducts can likewise continue to be used, even if the intermediate component has such air ducts, in order to allow widening of the surface according to the invention from the inside. Inexpensive, however, can be provided in the manufacture of new intermediate components, not to lead the compressed air through the intermediate component, as this significantly affects the cost of producing an intermediate component.

Instead, it can be completely dispensed with an air guide through the carrier body, because a simple mounting of the flexible surface on a sleeve core is possible when compressed air between the sleeve core and the flexible top is introduced. The compressed air can escape from an outlet nozzle with a flat outlet opening in order to allow a large-area air cushion between the surface and the carrier body. Surprisingly, however, even through round or otherwise shaped nozzles, a sufficient air cushion can be achieved, which allows the surface of the sleeve core to be wound, even though the surface has an inner diameter that is initially smaller than the outer diameter of the core.

The compressed air can be provided and used in a particularly simple manner by means of a so-called compressed-air pistol, since these compressed-air pistols are usually present in the printing companies anyway. During the Aufziehbewegung the surface can advantageously be carried out with this Aufziehbewegung the outlet nozzle to allow easy sliding of the surface on the support body.

The surfaces of the invention can be made of rubber, elastomer, photopolymer or compressible materials, optionally with a multi-layered structure. In contrast to a multi-layered and possibly multi-part manufacturer Sleeve allows the inventively provided flexibility of the top that the user himself can raise these surfaces on the support body and can replace the surfaces according to their wear or for the purpose of a motif change.

1. 1. Üblicherweise ist die Wandstärke von Hülsen, deren Oberflächen unter hohen Temperaturen aufvulkanisiert werden, auf ca. 3 mm beschränkt. Dementsprechend gering ist der erzielbare Unterschied zwischen dem Außendurchmesser des Druckzylinders und dem Außendurchmesser der das Motiv aufweisenden Oberfläche. Demgegenüber können erfindungsgemäß auch vulkanisierte oder bei hohen Temperaturen hergestellte Oberflächen, ggf. durch Verwendung eines Zwischenbauteils auf einem Druckzylinder, für nahezu beliebigen Hülsenduchmesser und -wandstärken bereitgestellt werden.
2. 2. Die Kosten von Hülsen mit einer Fotopolymer-Oberfläche können reduziert werden.
3. 3. Zwischenbauteile zwischen dem eigentlichen Druckzylinder und der Oberfläche können preiswerter hergestellt werden, da sie keine eingebaute Luftführung aufweisen müssen.
4. 4. Sämtliche bereits vorhandenen Hülsen können als Zwischenbauteil genutzt werden, auf welches eine erfindungsgemäße Oberfläche aufgezogen werden kann, um so eine große Vielfalt unterschiedlicher Gesamtdurchmesser mit demselben Trägerzylinder zu erzielen.
5. 5. Die Entsorgung nach Ermüdung, Beschädigung oder Abnutzung einer Oberfläche wird preiswerter, da weniger und ggf. sortenreineres Material entsorgt werden kann.
6. 6. Die Wiederaufbereitung derartig sortenreineren Materials wird vereinfacht gegenüber einer aus mehreren Schichten unterschiedlichen Materials bestehenden Hülse.
7. 7. Die Handhabung und der Transport der Oberfläche bei Kauf, Reparatur oder auch innerbetrieblich ist einfacher und preiswerter.
8. 8. Herstellung und Reparaturen sind einfacher möglich, da die ggf. aus einem einzigem Material bestehende Oberfläche materialgerecht behandelt werden kann, z.B. hinsichtlich Chemikalien oder Temperaturführung.

Compared to the preparation of a complete, suitable for flexographic printing, one-piece or consisting of sleeve core and outer sleeve two-piece pressure sleeve according to the invention results in a significant cost advantage, so that in particular prints with low quantities are made possible inexpensively. Overall, the following advantages result:

1. 1. Usually, the wall thickness of sleeves whose surfaces are vulcanised under high temperatures, limited to about 3 mm. Accordingly, the achievable difference between the outer diameter of the printing cylinder and the outer diameter of the surface having the motif is correspondingly low. On the other hand, according to the invention vulcanized or high-temperature surfaces, if appropriate by using an intermediate component on a printing cylinder, can also be provided for almost any tube diameter and wall thicknesses.
2. 2. The cost of sleeves with a photopolymer surface can be reduced.
3. 3. intermediate components between the actual impression cylinder and the surface can be made cheaper, since they need not have built-in air duct.
4. 4. All existing sleeves can be used as an intermediate component to which a surface according to the invention can be mounted, so as to a large variety of different overall diameter with the same To achieve carrier cylinder.
5. 5. The disposal after fatigue, damage or wear of a surface is cheaper, since less and possibly more sorted material can be disposed of.
6. 6. The reprocessing of such material of a more pure material is simplified compared to a sleeve consisting of several layers of different material.
7. 7. The handling and transport of the surface when buying, repairing or even in-house is easier and cheaper.
8. 8. Manufacturing and repairs are easier possible, since the possibly existing from a single material surface can be treated in accordance with the material, for example, in terms of chemicals or temperature control.

Claims (6)

1. Sleeve for the flexo-printing industry,
   having a flexible surface which

   - is made of rubber, elastomer, photopolymer or compressible materials,

   - displays the print motif,

   - can be mounted on a cylindrical bearer element,

   is designed tubular and has two front ends,

   - and can be pushed onto the bearer element as a component to be handled separately,

   where the inside diameter of the surface, when this is demounted from the bearer element, is smaller than the outside diameter of the bearer element,
   characterised in that
   the surface is designed tubular and flexible such that it may be distended by compressed air blown in from outside at the front end to be pushed onto the bearer element and in the opposite direction to that in which the surface is to be pushed on, enabling complete mounting on the bearer cylinder.
2. Sleeve in accordance with claim 1, characterised in that the inside of the surface has high slip-resistance enabling the surface to hold the bearer element firmly.
3. Sleeve in accordance with claim 1 or 2, characterised in that the surface contains a reinforcing material improving the firm seating on the bearer element.
4. Method of mounting a flexo-printing sleeve in accordance with any of the foregoing claims, characterised in that,
   compressed air is blown in from outside and between the flexible surface and the bearer element through an outlet jet, where the compressed air from outside is directed against the front end of the surface which is pushed onto the bearer element and in the opposite direction to that in which the surface is pushed on.
5. Method in accordance with claim 4, characterised in that the outlet jet is also pulled along when the upper side is pulled on.
6. Method in accordance with claim 4, characterised in that an outlet jet which generates a flat air current is used.