Sheet folding device

Abstract

To provide an apparatus capable of processing printed materials having various different characteristics by a buckle folding method with high quality and high productivity. The sheet folding device (1) comprises two folding rollers (20, 21) having a common folding gap (23) with an entrance side (24) and an exit side (25), a first pushing chamber (30) having a first pushing plane (31) for a selectively pushable folding plate (40) having a folding plate opening (41), the folding plate opening (41) of the selectively pushed folding plate (40) being arranged on the entrance side (24) of the folding gap (23), and a second pushing chamber (32) having a second pushing plane (33) for the selectively pushable folding plate (40) having the folding plate opening (41). The second pushing plane (33) is formed with an inclination α relative to the first pushing plane (31), and the second pushing chamber (32) is arranged on the entrance side (24) of the folding gap (23).

Description

[Technical Field]

[0001] The invention relates to a device for folding sheets having the features of the preamble of claim 1. The invention also relates to a method for folding sheets having the features of the preamble of claim 17.

[0002] Technical Field The invention is located in the technical field of the graphic industry, in particular in the field of buckle or flap folding of flexible sheet-like printed materials or in the industrial, i.e. high-quality and high-productivity, production of folded products, for example brochures, preferably made of paper, cardboard, paperboard, plastic or composite materials, in particular pre-printed paper.

[0003] Background technology Industrial folding of sheet-like printed materials is carried out using complex folding machines, which typically include a feeder for the sheets to be folded, at least one folding unit with multiple folding rollers, and a delivery for the folded products. Each folding unit of the machine may include a buckle folding mechanism and / or a knife folding mechanism. A buckle folding mechanism typically includes a series of folding rollers in a so-called folding roller frame, removable folding plates on both sides of the folding roller frame, and sheet deflectors.

[0004] German Patent Application No. 10 2006 055 301 A1 discloses a buckle folding mechanism with a number of folding rollers and a number of folding plates each having flat surfaces arranged parallel to one another. Such folding plates can be configured to be retractable, for example, by providing a retractable retractable folding plate retractable chamber. Retractable folding plates are realized, for example, in the "Stahlfolder" folding machine from Heidelberger Druckmaschinen AG.

[0005] German Patent No. 560466 also discloses a buckle folding mechanism having a plurality of folding rollers and a plurality of folding plates, in which the planes of two of the folding plates are arranged parallel to each other and the plane of a further folding plate is arranged non-parallel to both of the planes.

[0006] GB 290530 A1 discloses folding plates arranged to be angle adjustable.

[0007] On the part of manufacturers of graphic products, i.e., printing companies that carry out, for example, prepress, actual printing, and post-printing, there is a continuous demand for improved print quality while maintaining or even increasing production speed, especially when processing a large number of different printing substrates, for example paper types of different thicknesses.

[0008] Technical challenges The object of the invention is therefore to provide an improvement over the prior art, which in particular makes it possible to process substrates with different properties in a high-quality and highly productive manner in the buckle-folding method.

[0009] Solutions to problems through invention This problem is solved according to the invention by a device according to claim 1 and a method according to claim 17.

[0010] Advantageous and therefore preferred refinements of the invention are evident from the dependent claims and from the description and drawings.

[0011] 1. A device for folding sheets, in particular a buckle folding device or mechanism, according to the invention, comprising two folding rollers having a common folding gap with an entrance side and an exit side, a first pushing chamber having a first pushing plane for a selectively retractable folding plate having a folding plate opening, the first pushing chamber being configured so that the folding plate opening of the selectively retracted folding plate is located on the entrance side of the folding gap, and a second pushing chamber having a second pushing plane for the selectively retractable folding plate having a folding plate opening, the second pushing plane being formed at an angle to the first pushing plane, and the second pushing chamber being configured so that the folding plate opening of the selectively retracted folding plate is located on the entrance side of the folding gap.

[0012] A method according to the present invention for folding sheets using an apparatus according to the present invention, characterized in that for a first folding operation a selectively retractable folding plate is forced into a first retraction chamber, and for a second folding operation a selectively retractable folding plate is forced into a second retraction chamber.

[0013] Advantageous structure and effects of the device The invention advantageously allows for high-quality and high-productivity processing of printed materials with different characteristics in a buckle-folding process, and is used, for example, in the buckle-folding mechanism of an industrial folder.

[0014] During the continuous processing of various substrates in a folding machine, i.e., during successive folding operations, the specific substrates and thus the specific folding operations can cause problems. This problem can arise particularly when sheets are fed in a staggered manner and folded in a staggered manner within the folding plates, because in this case the sheets run at least partially adjacent to one another in the area of ​​the respective folding plate openings. Extensive research was therefore conducted to determine how this problem could be avoided, leading to the solution provided by the present invention. Thus, if a "standard" push-in chamber is used for a specific folding operation, rather than a push-in chamber that is tilted relative to the "standard" push-in chamber, the folding results can be significantly improved. Due to the tilt or modified angle, successive and staggered sheets (sheets in a staggered stream) also run adjacent to one another at a modified angle, avoiding or at least reducing the problem. The optimal angle for the tilt of the folding plates ultimately determined during the research is a compromise. That is, the more the folding plate is tilted, the flatter the sheet to be folded will be and therefore the better it will enter the folding plate, but on the other hand, the sheet will emerge again from the folding plate at a steeper angle and therefore the worse it will be.

[0015] Furthermore, during the investigation it was found that it can be advantageous to additionally displace the first two or three rollers of the roller frame (i.e. not the rollers arranged upstream) by a few millimeters, in particular upwards, compared to prior art devices not according to the invention, in order to improve the angle of entry of the sheet to be folded from the folding gap between the displaced folding rollers into the downstream arranged folding plate.

[0016] Terminology used in this application Through each folding plate opening (or opening for short), the sheets to be folded enter and exit the folding plate either continuously or in a staggered overlapping stream.

[0017] The term "inclined" is to be understood in the present application in relation to an indentation plane as follows: an indentation plane that is inclined relative to another indentation plane forms an angle with the other indentation plane that is different from zero, or in other words, both indentation planes are not parallel to each other.

[0018] The term "selectively" is understood in this application to mean that, in relation to the folding plates, the folding plates for folding are selectively arranged in the first or second pushing chamber depending on the folding operation to be performed by the device, for example, on the thin or thick substrate to be folded. Thus, during folding, the folding plates are respectively arranged in the selected pushing chamber. The sheet deflectors may also be selectively arranged, i.e., selectively arranged in places where no folding plates are arranged. For example, the folding plates or, alternatively, the sheet deflectors are preferably arranged in the respective pushing chambers.

[0019] The folding plate that can be selectively pushed into the first pushing chamber (or abbreviated: chamber) and removed again and the folding plate that can be selectively pushed into the second pushing chamber (or abbreviated: chamber) and removed again are preferably folding plates of the same structure, in particular identical folding plates, or alternatively may be two identical or at least similar folding plates.

[0020] Improved form of the invention In the following, preferred refinements (abbreviated as refinements) of the present invention as a device will be described, which refinements may be combined with one another if this is not technically precluded.

[0021] One refinement may be characterized in that the selectively pushable folding plate is arranged in the first push-in chamber or in the second push-in chamber, i.e., pushed in, and can be removed therefrom again.

[0022] A refinement may be characterized in that the device comprises a roller frame with two folding rollers and at least two further folding rollers, preferably a roller frame with a total of six, seven, eight or nine folding rollers. A refinement may be characterized in that the roller frame has a zigzag arrangement, i.e. the connecting lines between the rotation axes of the folding rollers of the roller frame together form a zigzag line.

[0023] A refinement may be characterized in that the device comprises at least one push-in chamber on a first side of the roller frame and at least one push-in chamber on an opposite second side of the roller frame. A refinement may be characterized in that the device comprises at least two push-in chambers on the first side of the roller frame and at least two push-in chambers on the opposite second side of the roller frame. A refinement may be characterized in that the device comprises at least three push-in chambers on the first side of the roller frame and at least three push-in chambers on the opposite second side of the roller frame. A refinement may be characterized in that the push-in chambers or the push-in planes of the push-in chambers are formed without inclination relative to the first push-in plane, i.e. all push-in chambers are parallel to one another.

[0024] A refinement can be characterized in that the device comprises push-in chambers at positions P1 to Pn successive through the roller frame in the sheet conveying direction, n≧2, odd numbers n being located on the first side and even numbers n being located on the second side, the first push-in chamber and the second push-in chamber being located at position P2, where the push-in chambers at the positions are preferably shaped and / or oriented in such a way that the opening of the respectively selectively pushed-in folding plate is located on the inlet side of the folding gap between the two folding rollers and simultaneously on the outlet side of the folding gap between the two folding rollers.

[0025] A refinement can be characterized in that a sheet deflector is selectively arranged in or adjacent to the push-in chamber at position P1, so that in this case no folding plate is arranged at position P1.

[0026] A refinement may be characterized in that a selectively pushable folding plate is arranged in the second push-in chamber at position P2, and that no folding plate is selectively arranged in one or more further push-in chambers on the second side, i.e., at least in position P4, or in other words, only one folding plate is selectively activated on the second side. A refinement may be characterized in that one or more sheet deflectors are selectively arranged in one or more further push-in chambers on the second side. A refinement may be characterized in that at least two sheet deflectors are connected to each other so that they can be inserted into and removed from the device together.

[0027] A refinement may be characterized in that one or more further positions on the second side, i.e. at least position P4, comprise respective further indentation chambers with respective further indentation planes, each of which is formed with an inclination relative to the first indentation plane. A refinement may be characterized in that the respective further indentation planes are formed with the same inclination compared to the second indentation plane. A refinement may be characterized in that the respective further indentation planes are formed with different inclinations compared to the second indentation plane. That is, for example, the first folding plate on the second side is inclined by 17° or 18° (relative to the first indentation plane), the subsequent second folding plate is inclined by 19° (relative to the first indentation plane), and the subsequent third plate is inclined by 20° (relative to the first indentation plane).

[0028] A refinement may be characterized in that one or more further positions on the first side, i.e. at least position P1, comprise respective further indentation chambers with respective further indentation planes, the respective further indentation planes being formed with an inclination relative to the first indentation plane. In this case, the expression "inclined relative to the first indentation plane" also includes an inclination relative to a plane parallel to the first indentation plane. A refinement may be characterized in that the respective further indentation planes are formed with an equal inclination compared to the second indentation plane. A refinement may be characterized in that the respective further indentation planes are formed with a different inclination compared to the second indentation plane.

[0029] A refinement may be characterized in that the inclination has a value between 15° and 20°. A refinement may be characterized in that the inclination has a value of 17°.

[0030] In the following, preferred refinements (abbreviated as refinements) of the invention as a method will be described, which refinements may be combined with one another if this is not technically excluded.

[0031] One refinement may be characterized by feeding the sheets to the device in a staggered flow, with a first sheet emerging from at least a given folding plate while a subsequent second sheet enters the folding plate.

[0032] A refinement may be characterized in that the section of the second sheet when entering runs adjacent to the section of the first sheet when leaving.

[0033] The features and combinations of features disclosed in the above technical fields, the invention and improvements section and the following example section may be combined with one another in any way to form further advantageous improvements of the invention.

[0034] Examples and drawings for the invention 2-4 show preferred embodiments of the present invention and its improvements. In the figures, corresponding features are designated by the same reference numerals. Repetition of reference numerals has been omitted for clarity. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 2 is a schematic cross-sectional view of the same device according to the prior art. [Figure 2] FIG. 2 is a schematic cross-sectional view of the same device according to the prior art. [Figure 3] 1 is a schematic cross-sectional view of a preferred embodiment of the device according to the present invention; [Figure 4] 1 is a schematic cross-sectional view of a preferred embodiment of the device according to the present invention; [Figure 5] 1 is a schematic cross-sectional view of a preferred embodiment of the device according to the present invention; [Figure 6] 1 is a schematic cross-sectional view of a preferred embodiment of the device according to the present invention;

[0036] The technical features shown in Figures 1 and 2 are preferably also present in each embodiment of the device according to the invention shown in Figures 3 to 6, and for this reason will not be described in detail again in these figures.

[0037] 1 shows an apparatus 1 with a conveying or processing device 2 for sheets 3 to be processed, i.e., folded, which are preferably fed to the apparatus 1 in an staggered overlapping stream. The apparatus 1 comprises a folding roller frame 10 with a plurality of folding rollers 11 arranged one after the other, each having a rotation axis 12. The folding roller frame 10 defines a first side 13 (e.g., the left side in the drawing) and a second side 14 (e.g., the right side in the drawing). Tie lines 15 between the rotation axes 12 form a zigzag arrangement 16. The apparatus 1 is preferably part of a folder 50 or folding mechanism 51.

[0038] 1 shows a first folding roller 20 of the folding roller frame 10, a second folding roller 21 arranged downstream of the first folding roller 20, and a further folding roller 22. The first folding roller 20 and the second folding roller 21 form a folding gap 23, as do each pair of further folding rollers. The folding gap 23 defines an entrance side 24 and an exit side 25, such that the sheet 3 to be folded enters the folding gap 23 at the entrance side 24 and exits again at the exit side 25 opposite the folding gap 23. The folding roller frame 10 also comprises an upstream-arranged roller 26.

[0039] 2 shows a first pusher chamber 30 with a first pusher plane 31 on the second side 14; a further pusher chamber 34 with a further pusher plane 35 on the first side 13; and a further pusher chamber 36 with a further pusher plane 37 on the second side 14. In each pusher chamber, a folding plate 40 with a folding plate opening 41 can be selectively inserted and removed again (direction 60) for a specific folding operation, with the folding plate opening 41 positioned near each folding gap. Through the folding plate opening 41, the sheet 3 to be folded enters and exits the respective folding plate. Each folding plate 40 preferably has an adjustable folding plate stop 42. The pusher chambers can be located at sequentially numbered positions P1 to P6, which correspond to each folding gap. In Fig. 1, all six pushing chambers or all six positions P1 to P6 shown are fitted with folding plates 40. In Fig. 2, folding plates 40 are fitted only to two pushing chambers at positions P2 and P3, and sheet deflectors 43 are instead arranged at the remaining positions P1, P4 to P6.

[0040] 1 shows (for illustration purposes only partially) a sheet 4 with a section 5 entering a folding plate 40 and a sheet 6 with a section 7 exiting the same folding plate 40, the sections 5, 7 running adjacent to one another during staggered folding. In order to avoid substrate-specific problems during this operation, especially when successive sheets 3 run adjacent to one another, the invention additionally provides a second, tilted push-in chamber. This second and further tilted push-in chamber are described in the following figures.

[0041] As can be seen in FIG. 3, in addition to the first pusher chamber 30 with the first pusher plane 31 at position P2, there is also a second pusher chamber 32 with a second pusher plane 33 at position P2. In this case, the second pusher plane 33 is inclined by an angle α, preferably 17°, relative to the first pusher plane 31 (for example, tilted downward in the drawing). As can be seen in FIG. 4, a folding plate 40 with a folding plate opening 41 is selectively inserted into the second pusher chamber 32 for a specific folding operation. Furthermore, while the folding plate 40 is inserted at position P3 for a specific folding operation, there is no folding plate present in the further pusher chamber for the specific folding operation; instead, a sheet deflector 43 is selectively present there. In this case, both sheet deflectors at positions P4 and P6 are mechanically coupled to each other via a connector 44 and can thus be used and removed together.

[0042] It should be noted that in an actual folding device, the push-in chamber and the folding plate are often longer than shown, so that the tilted push-in chamber 30 and the tilted folding plate 40 at position P2 may intersect with the push-in chamber 36 at positions P4 and P6. In such a case, when the folding plate 40 is present in the tilted push-in chamber 32 at position P2, the folding plate 40 may not be present at positions P4 and P6.

[0043] As can be seen in FIG. 5, at positions P4 and P6, in addition to the non-tilted push-in chamber at this position, there may also be an inclined push-in chamber 36 with an inclined push-in plane 37. In this case, the inclination α1 may be equal to or different from the inclination α. ​​Furthermore, as can be seen in FIG. 6, on the opposite side, at positions P1, P3, and P5, there may also be an inclined push-in chamber 34 with an inclined push-in plane 35. In this case, the inclination α2 and / or α3 may be equal to or different from the inclination α and / or α1. If several push-in chambers are present on one of the two sides 13 and 14, they may in particular be parallel to one another.

[0044] It may be specified that the folding rollers 17 shown in Fig. 4 (all three or only the upper ones) are arranged offset upwards by a few millimeters compared to the arrangement shown in Fig. 1, i.e., preferably in advance during assembly and permanently. Or, in other words, the groups of two or three folding rollers 17 have a different, preferably larger, spacing relative to the further folding roller groups of the roller frame. This advantageously changes the angle at which the sheet 3 to be folded enters the tilted folding plate 40 and, at the same time, the angle at which the sheet 3 to be folded re-exits. [Explanation of symbols]

[0045] 1 device 2 Conveying direction 3. Sheets, flow consisting of sheets (sheared and overlapping) 4 Entering seat 5. Entering sheet classification 6. Seats to be advanced 7. Seat classification 10 Folding roller frame 11 Folding roller 12 Rotation axis of folding roller 13 First Side 14 Second Side 15 Knotting Lines 16 Zigzag arrangement or zigzag lines 17 Folding roller 20 First folding roller 21 Second folding roller 22 Additional folding rollers 23 Fold gap 24 Entry side of fold gap 25 Advance side of fold gap 26 Roller located on the upstream side 30 First Pushing Chamber 31 First indentation plane 32 Second Pushing Chamber 33 Second indentation plane 34 Further push chamber on first side 35 Further indentation planes 36 Further push chamber on second side 37 Further indentation planes 40 Folding Plate 41 Folding plate opening 42 (adjustable) folding plate stopper 43 Sheet deflector 44 Connection for sheet deflector 50 folding machine 51 Folding mechanism 60 Direction of indentation and extrusion P1~Pn Position 1~n α Tilt or angle α1 Tilt or angle α2 tilt or angle α3 Tilt or angle

Claims

1. 1. An apparatus for folding sheets, comprising: two folding rollers (20, 21) having a common folding gap (23) with an entrance side (24) and an exit side (25); a first pushing chamber (30) having a first pushing plane (31) for a selectively pushable folding plate (40) having a folding plate opening (41), the folding plate opening (41) of the selectively pushed folding plate (40) being arranged on the entrance side (24) of the folding gap (23); and a second pushing chamber (32) having a second pushing plane (33) for the selectively pushable folding plate (40) having the folding plate opening (41), The second pushing plane (33) is formed with an inclination (α) relative to the first pushing plane (31), and the second pushing chamber (32) is configured such that the folding plate opening (41) of the selectively pushed folding plate (40) is arranged on the entrance side (24) of the folding gap (23).

2. 2. The apparatus of claim 1, wherein the selectively pushable folding plate (40) is disposed in the first push chamber (30) or the second push chamber (32).

3. 2. Apparatus according to claim 1, characterized in that the apparatus (1) comprises a roller frame (10) with the two folding rollers (21, 22) and at least two further folding rollers (22).

4. 4. The device (1) according to claim 3, characterized in that it comprises at least one push-in chamber (34) provided on a first side (13) of the roller frame (10) and at least one push-in chamber (30, 36) provided on an opposite second side (14) of the roller frame (10).

5. 5. The device according to claim 4, wherein the push-in chambers (34, 36) or the push-in planes (35, 37) of the push-in chambers (34, 36) are formed without inclination relative to the first push-in plane (31).

6. 4. The device (1) according to claim 3, characterized in that it comprises push-in chambers (30, 32, 34, 36) at positions P1 to Pn successive to one another through the roller frame (10) in the conveying direction (2) of the sheet (3), n≧2, odd numbers n being located on the first side (13) and even numbers n being located on the second side (14), and the first push-in chamber (30) and the second push-in chamber (32) being located at position P2.

7. 7. The device according to claim 6, further comprising a sheet deflector (43) selectively arranged in the push-in chamber (34) at the position P1 or adjacent to the push-in chamber (34) at the position P1.

8. 7. The device according to claim 6, characterized in that the selectively pushable folding plate (40) is arranged in the second push-in chamber (32) in position P2, and no selective folding plate is arranged in the second side (14), i.e. in one or more further push-in chambers (36) at least in position P4.

9. 9. The device according to claim 8, characterized in that one or more sheet deflectors (43) are optionally arranged in the one or more further pushing chambers (36) on the second side (14).

10. 10. The device according to claim 9, characterized in that at least two sheet deflectors (43) are connected (44) to each other so that they can be inserted into and removed from the device (1) together.

11. 7. The device according to claim 6, wherein one or more of the further positions on the second side (14), i.e. at least position P4, comprise respective further indentation chambers (36) with respective further indentation planes (37), each of which is formed with an inclination (α1) relative to the first indentation plane (31).

12. 12. The device according to claim 11, characterized in that the further indentation planes (37) are each formed with an equal inclination (α1) compared to the second indentation plane (33).

13. 12. The device according to claim 11, characterized in that the further indentation planes (37) are each formed with a different inclination (α1) compared to the second indentation plane (33).

14. 14. The device according to claim 6, wherein one or more further positions on the first side (13), i.e. at least position P1, comprise respective further indentation chambers (34) with respective further indentation planes (35), each of which is formed with an inclination (α2) relative to the first indentation plane (31).

15. 15. The device according to claim 14, characterized in that the further indentation planes (35) are each formed with an equal inclination (α2) compared to the second indentation plane (33).

16. 15. The device according to claim 14, characterized in that the further indentation planes (35) are each formed with a different inclination (α2) compared to the second indentation plane (33).

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