WO2020038795A2

WO2020038795A2 - Folding roller

Info

Publication number: WO2020038795A2
Application number: PCT/EP2019/071807
Authority: WO
Inventors: Uwe Evers
Original assignee: Uwe Evers
Priority date: 2018-08-20
Filing date: 2019-08-14
Publication date: 2020-02-27
Also published as: WO2020038795A3; DE202019101582U1; DE102018120189B4; DE102018120189A1

Abstract

The invention relates to a folding roller (1) for folding sheets of paper in a folder (2), comprising a roller core (11) and a nitrile rubber coating (10) applied thereto. The nitrile rubber selected for the coating (10) is an XNBR material, which results in improved operating properties.

Description

folding roller

The invention relates to a folding roller for folding paper sheets in a folding unit with a roller core and a coating applied thereon, which is made of nitrile rubber, and to a method for producing such a folding roller.

A folding roller of this type is specified in DE 699 16 748 T2. Several folding rollers are shown in a folding device, which are arranged in a sheet finishing device (finisher), for example a copying machine or a printer. In one embodiment, in which two pairs of folding rollers or pressure rollers are arranged one behind the other in the conveying direction and are coupled to conveyor belts, at least one pressure roller with a surface layer, for example made of rubber, such as, for. B. NBR aterial. As can be seen from the relevant FIG. 8, the folding rollers are provided with groove-like recesses in their area wrapped by the conveyor belts, the outer surface is offset radially inwards in the area of the grooves and does not run continuously. Gaps z. B. in transitions between metal and plastic material in which paint and dirt can settle, which can then be transferred to the product to be folded. In addition, the transport function of the conveyor belts requires a protrusion radially beyond the surface areas of the folding roller in question that are adjacent to the grooves. The effect of the rubber-coated roller is that it is possible to prevent the occurrence of knocking or knocking noises.

DE 20 2011 107 519 U1 shows rollers with a rubber-elastic roller jacket, in particular dyeing, dampening or varnishing rollers for printing machines, as well as rollers, rollers or wheels for roller application machines or for machines for working or processing wood, the rubber-elastic roller jacket essentially made of elastomeric or elastic plastic material, such as. B. XNBR material is made and is provided for reinforcement with a thin textile fabric, with which other problems are encountered than they occur in the area of folding rollers of the present invention. Another folding roller is specified in DD 274 606 A1. Such folding rollers are used in folding machines of folding machines. This known folding roller has, as is customary in the case of conventional folding rollers of this type, corrugated metal strips and strips of elastic material which are applied alternately all round to a metallic core and which slightly protrude beyond the surface of the metal strips. So that the user of the folding rollers can fully restore the functionality himself in the event of partial wear, this known folding roller provides for the core, which is attached to the ground metallic rollers, with the inner diameter and the side surfaces ground. tall rings are axially clamped to one another to form a twisted unit, the ground metal rings preferably having a shoulder on one side surface which serves as a seat for a ring made of metallic material. Although the user should be able to restore the functionality of the folding roller in accordance with the task in hand, this is difficult and time-consuming and material-consuming because of the high precision required, especially since a large number of folding rollers are installed in folding machines.

The DD 228 519 B5 shows the use of folding rollers in pocket folding machines with a device for setting the folder geometry. No details are given on the structure of the folding rollers per se.

DE 10 2014 007 495 A1 also shows a folding roller for use in a folding device, the folding roller having at least one rubber-elastic insert in the region of the conveyor belts of a belt line interacting with it, which insert is introduced into associated grooves in the folding roller body and, for example, as commercially available rings are made of NBR-70 material or polyurethane. This is to reduce the wear on the conveyor belts and at the same time make the setting of the folding rollers or the folding roller gap less sensitive and therefore less prone to failure. The conveyor belts inserted into the grooves of the folding roller protrude radially about 0.05 to 0.5 mm beyond the outer surface of the folding body. The elasticity of the inserts is intended to make the conveyor belt flexible in the radial direction of the folding roller. DE 10 2013 019 400 A1 shows a pocket folding station of a sheet folding machine with a plurality of folding rollers, at least one folding roller being provided with at least one bearing element in the area of its lateral surface and a supporting element being supported on the bearing element. Further folding rollers in connection with folding devices are shown in DE 10 2006 031 983 B3 and DE 297 22 173 U1. It is known that, in the case of conventional folding rollers, either polyurethane rings or spiral-shaped polyurethane are glued into prefabricated recesses in the roller body. Knurled sections of metal are located between the glued-in polyurethane, which can repeatedly cause marks (imprints) on the substrate, such as paper. These folding rollers - which must be done by the manufacturer or the supplier - can only be reground once or twice, since the metal core of the roller is always reduced in diameter by grinding. Thus the core is too small at some point and the rollers fall out of the area to be adjusted, which is required for the exact guiding of the sheets to be folded. It is also necessary to frequently clean the coating of the folding roller in order to avoid contamination and to maintain an exact function on the surface, for which purpose special, cost-intensive cleaners are required in order to minimize the durability of the polyurethane. Alternate in the axial direction on the surface z. B. metal and plastic or polyurethane, as is the case with conventional folding rollers, there are often narrow gaps in which color and dirt can accumulate, which are then transferred to the product to be folded and leave interference marks.

The object of the present invention is to provide a folding roller of the type mentioned at the outset and a method for producing a folding roller which results in increased wear resistance with the best possible function.

This object is achieved in the folding roller with the features of claim 1 and in the method with the features of claim 7. By producing the coating from XNBR material, as has been shown in investigations by the inventor, a considerable increase in the service life of the folding rollers is achieved in comparison to previous folding rollers. There is also a significantly improved resistance to damage from cleaning agents in comparison z. B. to previous polyurethane coatings. Common cleaning agents can therefore advantageously be used for cleaning. In addition, the coating enables long-term high folding accuracy to be achieved. The costs for producing or renewing the coating are also low in comparison to conventional folding rollers.

In order to achieve an advantageous function with high folding accuracy and inexpensive production or renewal of the coating, the measures contribute to the roller core being coated over the entire area in the coating area without interruption in the axial direction. Also, the full-surface coating on the substrate or paper to be processed means that no marks (imprints) can be caused by knurled metal parts. After the coating has worn out, it can be replaced as often as required. In addition, the full-surface coating made of the XNBR material has the further essential advantage that electrostatic charging and the disadvantages and effort required to prevent it are avoided.

As a result of the further measure that the coating is provided with a grooving running in the circumferential direction, ink and powder or the like of the printing material can be thrown out of the folding unit by rotation. It is also advantageous here that the grooving runs obliquely at least in sections with respect to a cross-sectional plane perpendicular to the roll axis, in particular in the form of cross-grooving. Further advantages for the function and cleaning result from the fact that the corrugation in cross-section has continuously opening grooves, in particular trapezoidal or V-shaped grooves with a round groove base. The recesses that are made in this way and open to the outside in cross-section, in particular trapezoidal or rounded, prevent particles that accumulate from getting stuck in the recesses.

For a cost-effective production of the folding roller, it is advantageously provided that a coating material made from nitrile rubber is produced and provided and that the coating material is wound onto the roll core in a tough consistency and then hardened.

For the production and renewal of the coating and the function, it is also advantageously provided that the coating material is applied over the entire surface of the roll core without interruption in the direction of the roll axis.

For production and function, the measures are advantageous in that a grooving with grooves running in the circumferential direction is introduced, in particular ground, into the hardened coating material. Another measure which is advantageous for processing and an exact function is that the hardened coating material is ground to size before incorporation of the grooving. The folding rollers provided with the above-mentioned measures according to the invention can be installed in any common folding machine, in particular also high-performance machines.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawings. Show it:

1 a folding unit with several folding rollers and folding pockets in a schematic side view,

2 shows a section of a folding roller in side view,

3A shows a section of a folding roller in longitudinal section,

3B shows a detail X of the folding roller according to FIG. 3A in the area of a coating and

Fig. 4 shows a cross section of a folding roller.

Fig. 1 shows schematically a folding unit 2 with six folding rollers 1 (1a, 1b, 1c, 1d, 1e, 1f) with fold pockets 21 arranged in between in the passage path from a sheet inlet E to a sheet outlet A on alternating sides, as from the prior art Known pocket folding technology. The folding pockets have a shaft 210 and a stop 211 for the printing material or paper during the folding processes. 2 shows a section of a folding roller 1 according to the invention with a grooving 101 in a coating surface 100. As the further FIGS. 3A, 3B and 4 show, the folding roller 1 has a generally metallic roller core 11 with one applied thereon Coating 10, in the coating surface 100 of which the grooving 101 is incorporated. For example, the thickness a (see FIG. 4) is

Coating 10 in the range between 3 and 6 mm, such as between 4 and 5 mm. The roller core 11 z. B. a diameter d1 between 30 and 40 mm, such as. B. 35 mm, so that z. B. gives a total diameter d2 of the folding roller between 38 and 50 mm with a thickness a of the coating 10 between 4 and 5 mm.

The grooving 101 consists of grooves made in the circumferential direction of the folding roller 1 in the coating surface 100, which preferably (but not necessarily) run obliquely to a cross-sectional plane perpendicular to the roller axis and is designed, for example, as cross-grooving, as shown in FIG. 2 seen. The cross-section of the grooves (in a side view of the folding roller 1) is shaped to widen outwards, as can be seen from FIG. 3A and in particular from the enlarged representation of FIG. The groove shape can be trapezoidal, V-shaped with a rounded base or trough-shaped or wavy, the opening angle a of the grooves z. B. in the range between 30 ° and 70 °, such as. B. 45 ° and 65 °, in particular between 50 ° and 60 °. The depth t is preferably between 1 and 3 mm, in particular between 1, 2 and 2 mm, preferably between 1, 4 and 1, 6 mm. This configuration of the grooving 101 advantageously removes deposited dirt particles or the folding roller 1 can be easily cleaned, as stated at the beginning. The coating 10 is applied over the entire axial extent to the entire area of the roller core 11, which is designed, as usual, with lateral sections which extend beyond the coating area and with bearing parts for insertion into a relevant folding unit 2. The full-surface formation of the coating 10 results in advantages for the function and manufacture and a possible reworking or renewal of the coating 10.

According to the invention, a nitrile rubber, namely an XNBR material, a subspecies of NBR material, which has a tough consistency, is used as the material for the coating 10. It is preferably wound on the roller core 11 of the folding roller 1 and then cured, in particular in an oven or convector. After cooling, the coating is ground to size and provided with the grooving 101, preferably by grinding. This configuration of the folding roller 1 with the coating 10, which in particular is formed over the entire surface and is grooved in the manner mentioned, achieves a high mechanical and chemical resistance, in particular also against damage caused by cleaning agents. In addition, the coating 10 can be renewed as often as desired and it results in a high folding accuracy. Markings due to knurled areas between sections of the coating, as with conventional folding rollers, are avoided. The grooving incorporated in the manner according to the invention, in contrast to conventional folding rollers with grooving running parallel to the axis, prevents particles such as ink and powder of the printing material from becoming lodged in the grooving, since dirt particles are thrown out by the rotation. The full-surface coating with the XNBR material also prevents electrostatic charging and the associated disadvantages in the folding processes. The material of the coating 10 used z. B. a hardness between 50 and 90, in particular between 60 and 80 Shore A and a high tear strength of z. B. between 10 and 25 N / mm ² , in particular between 15 and 20 N / mm ² , and an elongation at break in particular in the range between 500 and 550% (both properties measured according to Din 53504). Further properties of a coating 10 of this material tested according to the invention are an elasticity between 30 and 50% (according to Din 53512) and an abrasion in the range between 50 and 80 mm ³ , in particular between 60 and 70 mm ³ (according to Din ISO 4649).

Claims

Claims 1. folding roller (1) for folding paper sheets in a folding unit (2) with a

Roll core (11) and a coating (10) applied thereon, which is made of a nitrile rubber,

characterized,

that an XNBR material is selected as the nitrile rubber of the coating (10). ,

2. folding roller according to claim 1,

characterized,

that the roller core (11) is coated over the entire area in the coating area without interruption in the axial direction.

3. folding roller according to one of the preceding claims,

characterized,

that the coating (10) is provided with a groove (101) running in the circumferential direction.

4. folding roller according to claim 3,

characterized,

that the grooving (10) extends obliquely at least in sections with respect to a cross-sectional plane perpendicular to the roll axis.

5. folding roller according to claim 4,

characterized,

that the grooving (10) is designed as a cross grooving.

6. folding roller according to claim 3, 4 or 5,

characterized,

that the grooving (10) has cross-sections which are continuously opening towards the outside, in particular trapezoidal or V-shaped with a round groove base.

7. A method for producing a folding roller (1), in which a roller core (11) is provided with a coating (10), a coating material being produced and provided from nitrile rubber,

characterized,

that the coating material is wound onto the roll core (11) in tough consistency, over the entire area without interruption in the direction of the roll axis and then hardened and

that a grooving (10) with grooves running in the circumferential direction is introduced into the hardened coating material.

8. The method according to claim 7,

characterized,

that the grooving (10) is ground in.

9. The method according to claim 8,

characterized,

that the hardened coating material is ground to size before incorporation of the grooving (10).