EP2953874A1

EP2953874A1 - Transport device for paper, and paper processing device

Info

Publication number: EP2953874A1
Application number: EP14710493.9A
Authority: EP
Inventors: Jörg SCHEFFLER
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-02-08
Filing date: 2014-02-07
Publication date: 2015-12-16
Anticipated expiration: 2034-02-07
Also published as: EP2953874B1; DE102013002122A1; WO2014121939A1; US9725851B2; US20160032526A1

Abstract

The invention relates to a transport device for paper, said device having a conveyor belt (25) which is guided by at least two rollers (12a, 12b), which consists of metal and is air-permeable, and the upper section of which forms the transporting section (25a) and the lower section of which forms the returning section (25b). The device also has a vacuum generator arranged below the upper section. The conveyor belt (25) consists of a metal mesh so as to be easy to produce and assemble.

Description

Transport device for paper and

Paper processing device Description

Technical field of the invention

The invention relates to a transport device for paper according to the preamble of claim 1 and to a paper-processing device according to claim 16.

State of the art

If elements made of paper have to be moved with exact position, it is known in the art to use so-called suction belts for this purpose. Such suction belts are usually made of rubber or a similar material and have a plurality of holes. The transport device has at least two rollers, over which this suction belt runs and below the upper portion of the conveyor belt serving as a suction conveyor belt (ie below the transport section of the conveyor belt) is provided with a vacuum acted upon so-called suction box, the top has a plurality of openings, so that In the suction box acting vacuum on the one hand sucks the transport section on the suction box, and on the other paper, which is located on the surface of the transport section, sucks on this surface.

Laser cutting machines have also become known in the art, with the aid of which one can cut very precise contours out of paper in order thus to generate, for example, letters, numbers or other characters in the form of breaks. Again, it is of course necessary to position the paper precisely with respect to the laser or transport, so that here, the use of appropriate suction belts is useful. Due to the high thermal

ÄHSTÄTiGUNGSKÖPifS However, laser loading does not allow the use of conventional suction belts, in particular made of a rubber or a rubber-like material, or would lead to extremely high levels of wear. It is therefore known to use a thin metal sheet as a conveyor belt in such laser cutting devices. This metal sheet, before being welded into an endless belt, is provided with a very large number of small holes by means of lasers, so that this metal strip can be guided in a conventional manner via a suction box. The disadvantage of such a metal strip are the very high costs both during its manufacture and during its assembly.

Subject of the invention

On this basis, the present invention therefore has the object, a generic transport device, which can be used even at high permanent or punctual temperatures, educate in such a way that it is much easier to manufacture and preferably also in the assembly. This object is achieved by a transport device having the features of claim 1.

According to the invention, the conveyor belt is also made of a metal, but not of a perforated metal sheet, but of a metal fabric. Such metal fabrics are produced for a variety of purposes in large quantities and at very low cost. It has been found that such a metal fabric over a wide range of mesh sizes and wire thicknesses the same purpose as the above-mentioned laser punched metal strip. It has also been found that such metal fabrics can be easily welded by plasma or laser welding into endless belts, and that their mechanical properties (in particular their tensile elongation) make them ideal for use as endless conveyor belts. Another advantage over the previous laser-punched metal bands is, that they are often even easier to clean. This is in the above-described, currently preferred application in laser cutting devices (claim 15) important because left by the laser cutting Abbrandreste (ash and the like) from the paper on the conveyor belt and should be removed as continuously as possible in continuous operation.

Another advantage is that the metal mesh scatters rather than reflects the laser light, greatly reducing the negative effects of the reflections. The unwanted reflections can be further reduced by sandblasting and / or nano-coating the metal mesh.

Further advantages and preferred embodiments of the invention will become apparent from the dependent claims and from the embodiment now shown in more detail with reference to the figures.

Brief description of the drawings

1 shows a highly schematic cross section through a laser cutting system in which a transport device according to the invention is used,

FIG. 2 shows the detail D from FIG. 1 in a likewise very schematized and not to scale sectional view,

Figure 3 is a plan view from direction D1 to that shown in Figure 2

4 shows the transport device of Figure 1 in a slightly more detailed

Representation, but the conveyor belt is not shown,

FIG. 5 shows a plan view from direction D2 in FIG. 4, FIG. 6 shows a plan view from direction D3 in FIG. 5,

7 shows FIGS. 4 to 6 shown in a perspective view

FIG. 8 shows that shown in FIG. 7 with the conveyor belt mounted,

FIG. 9 is a cut-away view of that shown in FIG. 8, FIG. 10 shows a variation from that shown in FIG. 1,

Figure 11 shows a preferred embodiment of a cleaning station and Figure 12 shows a variation to that shown in Figure 11.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows, in a schematic cross-sectional representation, an apparatus for producing laser cuts in flat paper blanks, such as greeting cards or the like. This device consists of four elements, namely a feed unit 40, a transport device 10, a laser 30 arranged above the transport device and a removal unit 50. The direction of transport of the paper is the direction T and the device can operate continuously, ie. H. the generation of the cutting contours by the laser is carried out at a constant transport movement by the transport device 10th

The feed unit 40 may be conventionally constructed, consisting of a smooth-surfaced table 42 and a series of transport rollers 44 which slide the paper blanks over the table to the transport device 10. The transport rollers 44 may be slightly rotated relative to the transport direction T from a 90-degree angle (Figure 1 a) and press the paper blanks to a stop, so that a more accurate positioning of the paper blanks is achieved. The removal unit 50 can also be conventional be constructed and may for example consist of a connector 52 and a conveyor belt 54. However, it would be just as possible, for example, immediately after the transport device 10 to provide a forklift or the like.

The essential elements of the transport device 10 according to the invention are two rollers 12a, 12b, wherein at least one of the two rollers, here the rear roller 12b, driven, the conveyor belt 25 and a plurality of axial fans 16, which below the upper portion (ie the TransportabSchnitts ) 25a of the conveyor belt 25 are arranged. For positioning these axial fans 16 (these axial fans 16 can basically be constructed like conventional fans for computer housings), a support 14 lying in the horizontal plane, which extends essentially from the front roller 12a to the rear roller 12b, serves. This carrier 14 has a plurality of openings; at the positions of the apertures, the axial fans 16 are arranged, as shown in Figure 1 only very schematically. The carrier 14 may also be substantially thinner in practice (this will be seen below with reference to FIGS. 4 to 9). The axial fans 16 are preferably located relatively close to the underside of the upper portion 25a of the conveyor belt.

The conveyor belt 25 according to the invention as a metal fabric, so usually made of a warp wires 27 and weft wires 26 fabric made. This is shown schematically in FIGS. 2 and 3. The wire thickness of the interwoven wires is preferably between 0.25 and 0.4 mm and the mesh size is preferably between 0.4 and 0.6 mm. The metal fabric is preferably made of stainless steel, for example V2A. Preferably, a so-called "normal wire cloth", that is, a plain weave wire cloth, a plain weave wire cloth or a body weave wire cloth is used .When using the metal cloth in body weave, the warp wires 27 preferably extend in the transporting direction a piece of metal mesh of suitable length and width is cut and the two end edges (usually the short edges) are preferably welded together by plasma or laser welding, so that an endless conveyor belt is formed.

Optionally, the transport device 10 may also have, for example, the following illustrated elements: input rollers 23, an output roller 20 and a lower cleaning brush 22 or a cleaning station. A preferred embodiment of such a cleaning station will be explained later with reference to FIGS. 11 and 12. In this case, the output roller 20 can also perform a cleaning function. The provision of at least one cleaning roller or cleaning brush is to be preferred in the preferred embodiment of the transport device described in the exemplary embodiment, since burnt residues from the transport device 10 generally have to be removed. If an output roller 20 is provided, as shown, at the end of the upper section 25a of the conveyor belt 25 (ie the transport section), then it must be driven in opposite directions to the rollers 12a, b, one on the lower, ie on the return, section of the conveyor belt acting cleaning brush 22 or cleaning roller can also be concurrently driven to the rollers 12a, b, ie in opposite directions to the returning lower portion 25b, which can lead to an improvement in the cleaning effect. Since the output roller 20 also acts on the processed paper blanks, this must be made of a relatively soft material, while the lower cleaning brush 22 may also consist of a relatively hard material. Of course, the lower cleaning brush 22 could also act on the conveyor belt 25 in the area of one of the two rollers (but already on the lower half in each case).

Cleaning of the lower portion 25b with a "chainsaw-type" cleaning device, the direction of movement of which is perpendicular to the transporting device, has also proven to be very advantageous In such a cleaning device, cleaning brushes run around in the manner of a chain saw between two rollers a straight line. In most applications, a slightly damp cleaning is preferable.

Above the transport device 10, the cutting laser 30 is arranged.

The operation of the device takes place, as already mentioned, continuously and at a preferably constant transport speed. By the axial fans 16, which suck air through the upper portion 25a of the conveyor belt 25, the paper blanks 40 fed in the exact position by the feed unit 40 are held in position. The air expelled from the axial fans 16 exits through the lower portion 25b of the conveyor belt and thus further contributes to the cleaning of the return portion of the conveyor belt 25. The provision of axial fans has compared to the provision of a suction box still the other great advantages of a significantly reduced energy demand and a significantly reduced noise (in conventional suction boxes radial compressor are used as a vacuum generator).

The laser 30 cuts the paper blanks lying on the upper portion of the conveyor belt, which leave the transport device 10 on the rear roller 12 b and are discharged via the discharge unit 50.

Figures 4 to 9 show the transport device 10 just described again in greater detail, wherein in the figures 4 to 7, the conveyor belt 25 is not shown. All elements are provided with reference numerals in accordance with FIG. 1, so that repetitions, if possible, are dispensed with. FIGS. 4 and 9 show very well that the horizontally extending carrier 14 can be made quite thin and that the drive motors of the axial fans 16 can lie outside the plane defined by the carrier 14. The diameters of the openings in the carrier 16 substantially correspond to the diameter of the blades of the axial fans used. It can be seen in particular in FIG. 6 that the carrier 14 extends between two side cheeks 18a, 18b, so that the two sections of the conveyor belt 25, the rollers 12a, 12b and the side cheeks 18a, 18b enclose an internal space in which the aforementioned carrier 14 is arranged.

In order to be able to tension the conveyor belt 25, at least one end of each side wall has a slot 19 extending in the transport direction, through which the axis of a roller, here the front roller 12a, extends, so that the distance between the two rollers 12a, 12b is variable is and thus the conveyor belt 25 can be stretched. Thus, the conveyor belt 25 in the finished, so welded to an endless loop state, are mounted, wherein it is laterally pushed onto the rollers 12a, 12b, this ancillary components such as the input rollers 23 may have to be dismantled, if necessary.

In order to achieve a further improved flatness of the transported paper in a central section of the upper section 25a of the conveyor belt 25, it is possible to provide two transverse struts 60a, 60b extending transversely to the transport direction, the uppermost points of which are above the uppermost points of the rollers 12a, 12b, so that a slightly raised central portion is formed, which is extremely flat. This is shown schematically in FIG. Figures 11 and 12 show a preferred embodiment of a cleaning station 70, which can be arranged below the return portion 25 of the conveyor belt 25, for example, at the location of the above-mentioned cleaning brush 22. This cleaning station 70 has a cleaning roller 71 which can be driven about an axis 73 and an open-topped container 76 for receiving cleaning liquid 77 (in the simplest case water). Preferably, a stripping roller 78 is further provided, which is driven in opposite directions to the cleaning roller. At least the outer jacket layer of the cleaning roller 71 is formed as a sponge (sponge jacket 74 - FIG. 1) or in the form of a brush (brush jacket 75 - FIG. 12). The cleaning roller 71 is preferably driven in the same direction of rotation as the rollers 12a, 12b. The cleaning roller 71 is positioned so that it presses from below against the returning portion 25 b of the conveyor belt 25 and immersed with a lower part in the cleaning liquid 77. By the rotation of the cleaning roller new cleaning fluid 77 is constantly added and promoted to the returning portion 25b of the conveyor belt. By the stripper roller, which is arranged in the direction of rotation of the cleaning roller between the cleaning liquid and the conveyor belt, the degree of humidification of the returning section can be adjusted. For this purpose, the radial distance between cleaning roller and stripping roller 78 is preferably adjustable.

Moist cleaning (especially with the cleaning station just described) has several advantages. First, a good cleaning of the conveyor belt of burned, ash and the like can be achieved. Furthermore, the moistening of the conveyor belt as such has advantages. On the one hand, evaporation refrigeration develops, in addition favored by the arrangement of the axial fans, ie, the conveyor belt, whose upper section 25a is exposed to laser energy, is cooled. Furthermore, the moistening can be adjusted so that the conveyor belt still adheres to its upper portion 25a a certain amount of liquid. This adhering liquid improves the adhesion of burnt, ash and the like, so that they do not pollute the back of the processed paper. The fabric structure of the metal conveyor strongly promotes the intentional adhesion of liquid. Another possible use of the conveyor belt according to the invention is in drying lines of paper, especially paper, which has been printed with an inkjet printer.

Claims

claims

1. Transport device (10) for paper with

an air-permeable conveyor belt (25) guided over at least two rollers (12a, 12b) and made of metal, whose upper section forms the transport section (25a) and whose lower section forms the return section (25b), and

a vacuum generator arranged below the upper section, characterized in that the conveyor belt consists of a metal fabric.

2. Transport device according to claim 1, characterized in that the conveyor belt (25) is made of a metal fabric strip whose end faces are plasma or laserverschweis together.

3. Transport device according to one of the preceding claims, characterized in that the vacuum generator has at least one arranged between transport section and rücklaufendem section axial fan (16).

4. Transport device according to claim 3, characterized in that the axial fan (16) acts directly on the transport section and the returning section.

5. Transport device according to claim 3 or claim 4, characterized in that the vacuum generator comprises a plurality of axial fans (16).

6. Transport device according to one of the preceding claims, characterized in that the tissue of the metal strip is a tissue in body binding, a fabric in linen weave or a fabric in a smooth bond.

7. Transport device according to one of the preceding claims, characterized in that at least one cleaning device is provided which acts on the returning portion (25b).

8. Transport device according to claim 7, characterized in that the cleaning device wets the conveyor belt (25).

9. Transport device according to claim 8, characterized in that the cleaning device as a cleaning station (70) with a drivable cleaning roller (71) and a liquid-filled, open-topped container (76) is formed, wherein the cleaning roller (71) is positioned in such a way an upper portion of its surface contacts the return portion (25b) of the conveyor belt (25), and a lower portion of the cleaning roller is located within the container (76).

10. Transport device according to claim 9, characterized in that the axis (73) of the cleaning roller (71) extend parallel to the axes of the rollers (12a, 12b).

11. Transport device according to claim 10, characterized in that the cleaning roller (71) in the same direction of rotation as the rollers (12a, 12b) is driven.

12. Transport device according to one of claims 9 to 11, characterized in that further comprises a parallel to the cleaning roller (71) extending, preferably opposite to the cleaning roller drivable Abstreifwalze (78) is provided, which touches a portion of the surface of the cleaning roller (71).

13. Transport device according to one of claims 9 to 12, characterized in that at least the outer shell portion of the cleaning roller is formed by a sponge. Transport device according to one of claims 9 to 12, characterized in that at least the outer shell portion of the cleaning roller (71) is formed by a brush whose bristles extend substantially radially to the axis (73) of the cleaning roller (71).

Transport device according to one of the preceding claims, characterized in that the conveyor belt is sandblasted and / or nanocoated.

Paper processing device with a transport device according to one of Claims 1 to 15 and a laser (30) arranged above the transport section (25a) for cutting paper.