Folding rollers, folding roller pairs and folding machines

Abstract

The invention relates to a folding roller having at least one circumferentially extending groove (6) and a ring (5) arranged at least partially in the circumferentially extending groove, comprising a material with a Shore A hardness in the range of 50 to 95 Shore A, characterized in that the ring (5) comprises at least one preferably axially outer elastic section (10), preferably a shoulder (10), which is at least partially movable and / or positionable and / or deformable in the radial direction with respect to the folding roller (1), the groove (6) and / or the bottom (11) of the groove. The invention advantageously enables both precise and trouble-free conveying and simultaneous folding of printing materials.

Description

Technical Field

[0001] The invention relates to a folding roller, a folding roller pair and a folding machine.

[0002] The technical field to which the invention belongs is the graphics industry and in particular the field of folding printing materials (eg paper). Background Art

[0003] Industrial folding of sheet-shaped printing materials is performed using folding machines, which generally comprise a feeder for the sheets and at least one folding device with a plurality of folding rollers. The folding devices of such folding machines can each comprise a folding mechanism of the folding type and / or a folding mechanism of the folding type.

[0004] The sheets are folded between two rotating folding rollers that press against each other. The circumferential surfaces of these folding rollers can be made of metal. These folding rollers can have grooves in which loops made of elastomer are received.

[0005] Document DE 7904616 U1 discloses a folding roller equipped with a friction bushing, which has rings made of elastically deformable material. These rings can be corrugated on their outer surface. Documents DE 2854957 A1 and DE 3743642 A1 disclose similar content.

[0006] Two known but disadvantageous solutions in the prior art are described in the accompanying Figure 1a and 1b The disadvantages of these known solutions are also described there. Summary of the Invention

[0007] The object of the present invention is therefore to propose solutions that are improved compared to the prior art and that in particular allow both the transport and the folding of printing materials to be carried out precisely and without disruption.

[0008] These objects are achieved according to the invention by means of a folding roller and other subjects. Advantageous and therefore preferred developments of the invention are apparent from the description and the accompanying drawings.

[0009] The material used according to the invention with a Shore A hardness in the range of 50 to 95 Shore is preferably an elastic material, more preferably an elastomer, and in particular polyurethane (PU), more particularly so-called hard PU, such as polyurethane rubber (Polyester-Urethan-Kautschuk).

[0010] In the present application, a "hard" material (especially hard PU) is understood to be a material with a Shore A hardness of 50 to 95 Shore, especially 60 to 80 Shore or especially 75+ / -5 Shore. This material is not foamed or foamed only insignificantly and is therefore essentially solid. This material can be, for example, the product named The advantage of hard PU as a material for the folding roller rings is that this material has a high resistance to discoloration and has a longer service life than rubber, for example, and is more "anti-slip" than rubber, that is, it has better conveying properties for the printed material.

[0011] The material used according to the invention with a Shore A hardness in the range of less than 50 Shore is preferably an elastic material, more preferably an elastomer, and in particular polyurethane (PU), more particularly so-called soft PU, such as polyurethane rubber.

[0012] In this application, "soft" materials (especially soft PU) are understood to mean materials with a Shore A hardness of less than 50. These materials are preferably foamed and thus essentially cellular (or porous), and thus compressible. Soft PU is particularly advantageous when transporting smooth paper.

[0013] As an alternative to polyurethane (hard PU or soft PU), polyethylene or polypropylene can be used as material, preferably as hard material or soft material, respectively.

[0014] The Shore hardness or Shore A hardness is a material characteristic value for elastic materials, elastomers and / or plastics and can be determined in accordance with the standards DIN EN ISO 868, DIN ISO 7619-1 and ASTM D2240-00.

[0015] According to the invention, the folding roller comprises at least one circumferentially encircling channel and a ring at least partially arranged in the circumferentially encircling channel, the ring comprising a material with a Shore A hardness in the range of 50 to 95 Shore A, characterized in that the ring comprises at least one elastic section which is at least partially movable and / or positionable and / or deformable in the radial direction with reference to the folding roller, the channel and / or the bottom of the channel.

[0016] The term "at least partially in radial direction" means, for example, that in addition to the radial component, there may also be an axial component of the mobility / positionability / deformability. Preferably, the axial component is negligible compared to the radial component, for example less than 10% or less than 5% or less than 1%.

[0017] The folding roller according to the present invention advantageously allows for both precise and seamless transport and folding of the printing material. These loops are preferably made of hard polyurethane. Nevertheless, the segments according to the present invention (hereinafter also referred to as "shoulder") advantageously allow these relatively hard loops to behave at least partially like soft polyurethane loops. This roller is simple and cost-effective to manufacture and maintain. Advantageously, the folding roller preferably only has loops made of hard polyurethane, and no loops made of soft polyurethane.

[0018] Another folding roller according to the first alternative of the present invention has a surface (i.e. a circumferential surface) consisting of a plurality of segments, wherein the segments are alternately composed of first segments with a low first Shore hardness and second segments with a high second Shore hardness in the axial direction (50), wherein the first segments are first rings, which comprise a material with a Shore A hardness in the range of less than 50 Shore, and is characterized in that the second segments are second rings, which comprise a material with a Shore A hardness in the range of 50 to 95 Shore.

[0019] This alternative folding roller according to the invention can also advantageously convey and simultaneously fold the printing material precisely and without interference. This roller is also simple and inexpensive to manufacture and maintain.

[0020] Another folding roller according to the second alternative of the present invention is a folding roller having rings for conveying and folding sheets consisting of printing material, wherein the rings are made of an elastic material (preferably PU, such as hard PU or soft PU), wherein either the rings each have a hard section and a soft section adjacent to each other, the latter (soft section) preferably being configured as a shoulder, or the rings adjacent to each other constitute a hard section or a soft section.

[0021] Another folding roller according to the third alternative of the present invention is a folding roller having grooves and rings surrounding the periphery for conveying and folding sheets of printing material, wherein either the grooves each have a varying depth in the axial direction and / or the rings each have a varying thickness in the axial direction.

[0022] The expression "thickness varying in the axial direction" means, for example, that the thickness of the ring is not constant (depending on or as a function of the axial position) or that the ring has thicknesses that differ significantly from one another at at least two axial positions. For example, the thickness of the ring may have steps. The thickness is preferably measured in the radial direction (or is the radial thickness).

[0023] Another folding roller according to the second and third replacement of the present invention can also advantageously accurately and without interference both convey and simultaneously fold the printing material. In addition, the roller or the ring of the roller is wear-resistant.

[0024] All folding rollers according to the invention each offer an excellent combination of sheet guiding properties and folding properties due to their design.

[0025] According to the invention, a ring made of elastic material is used for a folding roller having a peripherally circumferential channel for receiving the ring, wherein the ring has a varying thickness in the axial direction.

[0026] The ring according to the present invention (or its application) can advantageously be accurately and without interference both conveyed and simultaneously folded printing material. In addition, this ring is wear-resistant.

[0027] A preferred development of the invention can be characterized in that the section is a non-central section, ie is arranged non-centrally or eccentrically in the axial direction with respect to the ring.

[0028] A preferred development of the invention can be characterized in that the section is an outer section, ie is arranged outwardly in the axial direction with respect to the collar, preferably on a side edge of the collar.

[0029] A preferred embodiment of the present invention can be characterized in that a circumferentially surrounding chamber is formed between each of the segments and the bottom of each channel, and the chamber is filled with air or a compressible material other than air. These chambers advantageously and simply allow for radial mobility and / or positionability of the segments (or shoulders). These chambers (or corresponding cavities) preferably achieve a sufficiently hollow position for the shoulders, thereby enabling their mobility / positionability.

[0030] A preferred development of the invention can be characterized in that the chamber has a height measured in the radial direction that is constant in the axial direction, or in that the chamber has a rectangular cross section. By selecting the length and height of the rectangle, the spring rate of the section (or shoulder) can be precisely adjusted.

[0031] A preferred development of the invention can be characterized in that the chamber has a height, measured in the radial direction, which varies in the axial direction, or in that the chamber has a wedge-shaped cross section. The spring rate of the section (or the shoulder) can be precisely adjusted by selecting the wedge cross section (for example, by selecting the corresponding wedge angle).

[0032] A preferred refinement of the present invention may be characterized in that the Shore A hardness is in the range of 60 to 80 Shore A, or 75+ / -5 Shore A, and / or the material is an elastic material, an elastomer, or a hard polyurethane, wherein the material is solid, non-cellular, or non-foamed. By selecting the material and the Shore A hardness, the spring rate of the section (or shoulder) can be precisely adjusted.

[0033] Another preferred development of the first alternative of the invention can be characterized in that the first sections are made of elastomer or (preferably) of soft polyurethane, and the second sections are made of elastomer or (preferably) of hard polyurethane. This allows simple production using known materials.

[0034] Another preferred improvement of the first alternative of the present invention can be characterized in that these second rings are at least partially arranged in corresponding grooves surrounding the folding roller. Said grooves prevent undesired axial movement of the second ring and thus also of the first ring in a simple manner.

[0035] Another preferred development of the first alternative of the present invention can be characterized in that the first segments and the second segments are received on the folding rollers in a continuous manner (Stoβ-on-Stoβ), and the first segments have a radial projection relative to the second segments. The projection improves the transport of the printing material to be folded. The projection can be, for example, a few hundredths of a millimeter.

[0036] Another preferred development of the second alternative of the invention can be characterized in that, in both cases, the hard and soft segments differ from one another at least by having a lower or higher elasticity in relation to one another.

[0037] A preferred development of the ring according to the invention can be characterized in that the ring has one or two shoulders, wherein the thickness of the shoulders is reduced with respect to the thickness of the ring or with respect to the thickness of the ring at its thickest point.

[0038] Any combination of features of the present invention, its improvements, and its embodiments also constitutes advantageous improvements of the present invention. Furthermore, improvements of the present invention may include individual features or combinations of features disclosed in the "Technical Field," "Background Technology," and "Summary of the Invention" sections above. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The folding roller according to the present invention and its preferred improvements will be described below based on preferred embodiments with reference to the accompanying drawings. Corresponding features are denoted by the same reference numerals in the drawings.

[0040] The accompanying drawings show:

[0041] Figure 1a and 1b : Folding roller according to the prior art;

[0042] Figure 2 : A folding roller according to the present invention;

[0043] Figure 3 : A folding roller according to the present invention;

[0044] Figure 4 : A folding roller according to the present invention;

[0045] Figure 5 : A folding roller according to the present invention;

[0046] Figure 6 : a folding roller according to the present invention; and

[0047] Figure 7 : Folding roller according to the present invention. DETAILED DESCRIPTION

[0048] Figure 1a A folding roller 1 according to the prior art is shown, which cooperates with a further folding roller 2. The two folding rollers are preferably arranged in a folding machine 100 and serve to produce a folded product 101 from a material 102 to be processed.

[0049] The folding roller 1 has hard segments 3 and soft segments 4 alternating along the axial direction (direction 50 in the drawing). The hard segments 3 can be made of metal (particularly steel) and can be parts or sections of the folding roller. These segments can have ripples in the axial direction on their surface. The soft segments 4 can be made of soft polyurethane and designed as rings 5' to be received on the folding roller. These rings 5' can be arranged in a circumferentially circumferential channel 6 of the folding roller. The same applies to the folding roller 2.

[0050] The folding roller 1 has, with respect to its surface, a greater proportion of hard sections 3 and a smaller proportion of soft sections 4 , for example in a ratio of approximately 3:2 or approximately 4:3. The hard section of one roller overlaps the hard section of the opposite roller in respective overlapping regions 7 .

[0051] During operation, the hard segments 3 have the function of producing good folds in the material 102 to be processed (e.g., paper) (hereinafter referred to as the "folding" function), while the soft segments 4 have the function of ensuring good material transport (hereinafter referred to as the "gripping" function). The folding roller according to the invention, which will be described below, also has these two functions.

[0052] A disadvantage of this prior art solution is that in the respective overlapping regions 7 , clearly visible and therefore disruptive lines can form in the material to be processed 102 , which lines reduce the quality of the folded product. Another disadvantage is the wear of the roller surface.

[0053] Figure 1b A folding roller 1 according to the prior art is shown. This folding roller 1 also has hard sections 3 and soft sections 4 alternating along the axial direction 50. These sections may correspond to Figure 1a The hard segments 3 can be made according to the construction shown in FIG and have corresponding “folding” and “clamping” functions during operation. These hard segments 3 can have grooves in the axial direction on their surface.

[0054] The folding roller 1 has a relatively large proportion of soft sections 4 and a relatively small proportion of hard sections 3, for example in a ratio of about 2:5 or 3:5 or 4:5. The soft section 4 of one roller overlaps the soft section of the opposite roller in the respective overlap region 7. This overlap can be, for example, of the order of a few millimeters. Figure 1a In contrast, here no overlapping of the hard sections is provided, but rather an overlapping of the soft sections.

[0055] The drawback of this solution is that the creases produced due to these soft sections are not so precise, or have a more pronounced "clamping" function than a "folding" function.

[0056] Figure 2 A preferred embodiment of a folding roller 1 of a folding machine 100 according to the present invention is shown. The folding roller 1 preferably cooperates in rotation with another folding roller 2. These folding rollers are used to produce a folded product 101 from a material 102 to be processed (e.g., paper). The two folding rollers 1 and 2 can have a similar structure. Therefore, the structure of the folding roller 1 will be described below by way of example.

[0057] The folding roller 1 (or its roller core) can be made of metal (preferably steel) and (with reference to the axis of rotation of the folding roller 1) have hard segments 3 and soft segments 4 alternating in the axial direction 50. These hard segments 3 are composed alternately of first hard segments 3a and second hard segments 3b in the axial direction 50. The first hard segments 3a are preferably made of metal (especially steel) and can be fixed / non-detachable parts or sections of the folding roller 1. Alternatively, the first hard segments 3a can be made of hard polyurethane and designed as detachable loops. The second hard segments 3b are preferably made of hard polyurethane and can be detachable parts or detachable sections of the folding roller (or be received on the folding roller).

[0058] These soft sections 4 (or shoulders or bends) are preferably not made of soft PU (as expected according to the prior art), but according to the present invention are made of hard PU. In order to achieve the formation of soft sections despite the use of hard PU material, the following is provided according to the present invention in this embodiment: in the groove 6 surrounding the folding roller 1, a ring 5 is at least partially arranged as a segmented soft section 4. The Shore A hardness of the ring 5 is in the range of 60 to 90 Shore, preferably 60 to 80 Shore, and particularly preferably about 75 Shore. The material of the ring 5 is preferably solid, non-cellular or non-foamed. The ring 5 may have a recess (on the back side, i.e. facing the roller core) in its soft section.

[0059] The ring 5 may have a projection slightly beyond the surface of the folding roller, for example by a few hundredths of a millimeter. The ring 5 has a central section 5a (in the axial direction 50 with respect to the axis of rotation of the folding roller 1) and two axially outer sections 5b (in the axial direction 50). These sections 5b are elastically deformable and radially movable or displaceable with respect to the folding roller 1 and / or in particular with respect to the groove 6 in the folding roller and / or with respect to the bottom 11 of the groove (in the radial direction 51). The latter means that these sections 5b are radially moved or displaced into the groove under pressure (for example by squeezing between the two folding rollers 1 and 2), preferably with the size of the projection being in the order of magnitude of, for example, a few hundredths of a millimeter.

[0060] In the embodiment shown, the channel 6 has two sections: a central section 6a (in the axial direction 50) and two axially outer sections 6b (in the axial direction 50). The channel 6 has a depth 8a in section 6a and a smaller depth 8b in sections 6b. The depths are measured relative to the surface of the folding roller 1 in the region of the first hard section 3a. The circumferential channel of the folding roller 1 can be implemented, for example, as a recess in a metal roller. The bottom 11 of the channel 6 is preferably stepped: a central low step 11a and two adjacent, axially outer high steps 11b.

[0061] The ring 5 has a thickness 9a in section 6a, which is substantially equivalent to the depth 8a of the channel or slightly larger (in the case of a given protrusion). The ring 5 has a thickness 9b in section 6b, which is less than the depth 8b of the channel, for example, only 50%, 60%, 70%, 75%, 80% or 90% of the depth 8b of the channel. As a result, a chamber 12 is created between each (axially outer) shoulder 10 of the ring 5 and each bottom 11 (or step 11b at the bottom) or section 6b of the channel 6. The chamber 12 is preferably filled with air. Alternatively, the chamber 12 can be filled with a compressible material (such as soft PU). The chamber 12 preferably has a rectangular cross-section.

[0062] According to the invention, the cavity 12 enables the mobility or displacement of the respective shoulder 10 in the radial direction 51 within (or into) the cavity 12 .

[0063] Thus, during operation (ie, during conveying and folding of the material 102 to be processed), the shoulder 10 of the ring 5 , although made of hard PU, behaves like a soft PU and can provide a “clamping” function.

[0064] The ring 5 is preferably glued into the channel 6, in particular fixedly glued to the bottom 11 (or the step 11a of the bottom 11) of the channel 6. Excess adhesive can be collected in two side chambers 13 surrounding the periphery.

[0065] The ring 5 may optionally have a central (in the axial direction) and peripherally surrounding depression 14. This depression 14 can also enable the movability or displacement of the hard PU material of the ring 5 in the radial direction 51 in the section 15, thus also providing a "clamping" function in the section 15.

[0066] from Figure 2 It can be seen that the individual sections of the two folding rollers 1 and 2 are arranged offset to each other with an axial offset 52: the central section 5a of the ring 5 of the folding roller 1 is opposite the first hard section 3a of the folding roller 2, and vice versa. The shoulders 10 of the rings 5 ​​of the two folding rollers 1 and 2 are respectively opposite each other. In the case where the rings 5 ​​are respectively given to slightly exceed the (preferably metal) surface of the respective folding roller 1 or 2 and have a protrusion, these shoulders 10 are respectively slightly moved (or shifted) into the chamber 12 assigned thereto. This produces a "clamping" function, that is, these shoulders act as if they were made of soft PU. However, it is advantageous that soft PU is not used, but (in this embodiment) only hard PU is used.

[0067] In the embodiment shown, the bottom 11 of the groove 6 can also be constructed without steps. In this way, as long as the thickness 9b of the shoulder 10 of the ring 5 remains the same, the chamber 12 can be deeper. The thickness 9b can also be selected more greatly, so that these chambers 12 are not too deep. In addition, in this embodiment, in the region of these shoulders 10, the projection of the ring 5 can also be selected to be greater than 15 / 100 millimeters, or on the contrary, the ring 5 can be centrally (i.e., axially between the shoulders) such as by turning to and being constructed thinner.

[0068] Figure 3 Another preferred embodiment of the present invention is shown. Figure 2 , however, the chambers 12 here have a substantially wedge-shaped cross section, and the bottom 11 of the channel 6 is not stepped (with the above-mentioned two steps 11 a and 11 b ), but is stepless.

[0069] Figure 4 Another preferred embodiment of the present invention is also shown. Figure 2 , but these steps 11a and 11b are designed differently here: the depth 8b of the axially outer bottom is deeper than the depth 8a of the central bottom. Or in other words: the channel 6 has a central high step 11a and two adjacent, axially outer low steps 11b.

[0070] In all according to Figures 2 to 4 In the embodiment shown, the spring rates of the ring 5 shown here (or its axially outer section / shoulder 10) can be set as follows: a hard PU material is selected; the axial length and radial thickness of the shoulder 10 are selected; and / or the axial length and radial depth of the channel 6 below the shoulder 10 are selected. In this case, the ring 5 and in particular its shoulder 10 are considered to be a spring.

[0071] Figure 5 Another preferred embodiment of the present invention is also shown. Figure 2 , but in this embodiment two types of segments (or loops 5 and 5 ′) are employed: loop 5 is hard or made of hard PU, and loop 5 ′ is soft or made of soft PU.

[0072] The loops 5 are T-shaped and are located in channels 6 of the folding roller 1 ; the channels 6 themselves are stepless.

[0073] There are corresponding spaces (or corresponding gaps 16) between the rings 5 ​​in the axial direction. The rings 5' are located on the surface of the folding roller 1 and between the rings 5 ​​(or in the gaps 16). The rings 5' have radial projections 19 beyond the rings 5 ​​to improve the "clamping" function. The rings 5 ​​are held axially by the grooves 6; the rings 5' are held axially by the rings 5.

[0074] The folding roller 2 has grooves 17 in which soft rings 5' or rings 5' made of soft polyurethane are received; these rings 5' of the folding roller 2 are opposite the rings 5' of the folding roller 1. The rings 5 ​​of the folding roller 1 are opposite a hard surface section 18 of the folding roller 2 (for example, made of steel).

[0075] The rings 5' of the folding rollers 1 and 2 work together to provide a "clamping" function; the rings 5 ​​and the segments 18 work together to provide a "folding" function. The rings 5' of the two folding rollers 1 and 2 can be designed identically. As an alternative to the embodiment shown, the ring 5' of the folding roller 2 can be designed slightly wider than the ring 5' of the folding roller 1, so that the ring 5' of the folding roller 2 overlaps the ring 5 of the folding roller 1 and improves the "clamping" function.

[0076] Figure 6 Another preferred embodiment of the present invention is shown. The structure is similar to Figure 2 , however, the rings 5 ​​each have only one axially outer section 5 b configured as a shoulder 10. One ring 5 (or one shoulder 10 thereof) of the folding roller 1 overlaps only one ring 5 (or one shoulder 10 thereof) of the folding roller 2. The sides of these rings 5 ​​that do not have a configured shoulder do not overlap or overlap only insignificantly.

[0077] Figure 7 Another preferred embodiment of the present invention is shown. Figures 2 to 6 The difference is, Figure 7 The two folding rollers 1 and 2 are shown spaced apart from each other so that the loops 5 and in particular their curvatures can be clearly seen. However, during operation, the rollers press against each other and the loops 5 are pressed into the grooves 6, so that the curvatures are not obvious or not so obvious. The structure is similar to Figure 2 , but in this embodiment, the axial section for the "clamping" function is not caused by a shoulder, but by the curvature of the ring 5. This ring 5 is designed, for example, so that its cross section corresponds to a curved or bent rectangle. The curvature is preferably selected so that the central section protrudes (radially) relative to the axially outer sections.

[0078] Reference Signs List

[0079] 1 Folding roller

[0080] 2 folding rollers

[0081] 3 Hard segments

[0082] 3a First hard section (made of steel)

[0083] 3b Second hard segment (made of hard PU)

[0084] 4 Soft segment (composed of soft PU)

[0085] 5 rings (hard)

[0086] 5' loop (soft)

[0087] 5a Central section of loop

[0088] 5b Axially outer section of the ring

[0089] 6 slots

[0090] 6a Central section of the channel

[0091] 6b Axially outer section of the groove

[0092] 7 Overlapping area

[0093] 8a Groove depth

[0094] 8b Groove depth

[0095] 9a Thickness of the ring

[0096] 9b Thickness of the ring

[0097] 10 Shoulder of the ring / axially outer section of the ring

[0098] 11 Bottom of the channel

[0099] 11a Steps at the bottom of the channel

[0100] 11b Steps at the bottom of the channel

[0101] 12 chambers

[0102] 12a Chamber height

[0103] 13 Side chamber

[0104] 14 Central depression

[0105] 15 sections

[0106] 16 vacancies

[0107] 17 slots

[0108] 18 Surface segments (hard)

[0109] 19 Radial protrusion

[0110] 50 Axial direction (of folding roller and / or ring)

[0111] 51 radial direction

[0112] 52 Axial misalignment

[0113] 100 Folding Machine

[0114] 101 Folding Products

[0115] 102 Materials to be processed

Claims

1. A folding roller comprising at least one peripherally extending channel (6) and a ring (5) at least partially arranged in the peripherally extending channel, the ring comprising a material having a Shore A hardness in the range of 50 to 95 Shore A, It is characterized by: The ring (5) protrudes from the surface of the folding rollers (1, 2) by a few hundredths of a millimeter and comprises at least one elastic axial section which is at least partially movable and / or positionable and / or deformable in the radial direction with respect to the folding rollers (1, 2), the channel (6) and / or the bottom (11) of the channel.

2. The folding roller according to claim 1, It is characterized by: The elastic axial section is a non-central section, ie is arranged non-centrally or eccentrically in the axial direction (50) with reference to the ring (5).

3. The folding roller according to claim 1 or 2, It is characterized by: The elastic axial section is an outer section, ie is arranged outwardly in the axial direction (50) with reference to the ring (5).

4. The folding roller according to claim 1 or 2, It is characterized by: A respective circumferentially surrounding chamber (12) is formed between the elastic axial section and the bottom (11) of each channel (6), and The chamber is filled with air or a compressible material other than air.

5. The folding roller according to claim 4, It is characterized by: The chamber (12) has a height (12a) measured in the radial direction which is constant in the axial direction, or The chamber has a rectangular cross-section.

6. The folding roller according to claim 4, It is characterized by: The chamber (12) has a height (12a) measured in the radial direction which varies in the axial direction, or The chamber has a wedge-shaped cross-section.

7. The folding roller according to claim 1 or 2, It is characterized by: The Shore A hardness is in the range of 60 to 80 Shore or 75 + / - 5 Shore, and / or The material is an elastic material, wherein the material is solid or non-cellular or non-foamed.

8. The folding roller according to claim 1 or 2, It is characterized by: The ring (5) adjoins a section (3a) of the folding rollers (1, 2) made of steel or a further ring (5) made of an elastomer having a Shore A hardness in the range of 90 to 95 Shore.

9. The folding roller according to claim 1 or 2, It is characterized by: The Shore A hardness is in the range of 60 to 80 Shore or 75 + / - 5 Shore, and / or The material is an elastomer, wherein the material is solid or non-cellular or non-foamed.

10. The folding roller according to claim 1 or 2, It is characterized by: The Shore A hardness is in the range of 60 to 80 Shore or 75 + / - 5 Shore, and / or The material is a hard polyurethane, wherein the material is solid or non-cellular or non-foamed.

11. A folding roller with a ring for conveying and folding sheets of printing material. in, The ring protrudes a few hundredths of a millimeter from the surface of the folding rollers (1, 2) and is made of elastic material, and The rings each have a hard section and a soft section (3, 4) adjacent to each other.

12. The folding roller according to claim 11, It is characterized by: The hard section and the soft section differ from one another at least by virtue of their lower or higher elasticity relative to one another.

13. A folding roller having a groove and a ring around its periphery for conveying and folding sheets of printing material. in, The ring protrudes from the surface of the folding rollers (1, 2) by a few hundredths of a millimeter, wherein the groove (6) has a varying depth in the axial direction (50) and / or the ring has a varying thickness (9a, 9b) in the axial direction (50).

14. A folding roller pair for conveying and folding sheets of printing material, the folding roller pair comprising at least one folding roller (1, 2) according to any one of the preceding claims 1 to 13.

15. The folding roller pair according to claim 14, It is characterized by: The folding rollers (1, 2) of the folding roller pair are arranged offset relative to one another in the axial direction (50) with respect to their grooves (6) or rings.

16. The folding roller pair according to claim 15, It is characterized by: The channels (6) and / or loops of one of the two folding rollers (1, 2) have an axial offset (52) with respect to the same channels (6) and / or loops of the other of the two folding rollers (1, 2).

17. A folding machine comprising at least one folding roller (1, 2) according to any one of claims 1 to 13 or at least one folding roller pair according to any one of claims 14 to 16.

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