Device and method for folding sheets

Abstract

A device according to the invention for folding sheets, comprising two folding rollers (20, 21) with a common folding gap (23) which has an inlet side (24) and an outlet side (25), comprising a first insertion slot (30) with a first insertion plane (31) for an optionally insertable folding pocket (40) with a folding pocket opening (41), wherein the first insertion slot (30) is configured such that the folding pocket opening (41) of the optionally inserted folding pocket (40) is arranged on the inlet side (24) of the folding gap (23), and comprising a second insertion slot (32) with a second insertion plane (33) for an optionally insertable folding pocket (40) with a folding pocket opening (41), is characterized in that the second insertion plane (33) is configured with an inclination (α) to the first insertion plane (31) and that the second insertion shaft (32) is designed in such a way thatthat the folding pocket mouth (41) of the optionally inserted folding pocket (40) is arranged on the entry side (24) of the folding gap (23). The invention advantageously enables the high-quality and high-productivity processing of printing materials with different properties using the pocket folding method. The invention is used, for example, in pocket folding units of industrial folding machines.

Description

invention

[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. field of technology

[0002] The invention lies in the technical field of the graphic industry and there in particular in the field of pocket folding or compression folding of flexible, sheet-shaped printing materials or the industrial, ie high-quality and highly productive, production of folded products such as brochures, preferably made of paper, cardboard, paperboard, plastic or composite material, in particular of printed paper. State of the art

[0003] The industrial folding of sheet-shaped printing materials is carried out using complex folding machines, which typically comprise a feeder for the sheets to be folded, at least one folding unit with a plurality of folding rollers, and a delivery unit for the folded products. The machine's folding units can each comprise buckle plate folding units and / or knife folding units. Buckle plate folding units typically comprise a series of folding rollers in a so-called folding roller frame, along with removable folding plates and sheet deflectors on either side of the folding roller frame.

[0004] DE102006055301A1 discloses a pocket folding unit with several folding rollers and several folding pockets, the planes of which are arranged parallel to each other.

[0005] Such folding pockets can be designed to be insertable, for example, by providing slots for the optionally insertable folding pockets. Insertable folding pockets are implemented, for example, in the "Stahlfolder" folding machines from Heidelberger Druckmaschinen AG.

[0006] DE560466C also discloses a pocket folding unit with a plurality of folding rollers and a plurality of folding pockets, wherein the planes of two folding pockets are arranged parallel to each other and the plane of a further folding pocket is not arranged parallel to these two planes.

[0007] GB290530A discloses a folding pocket which is arranged in an angle-adjustable manner.

[0008] On the part of the manufacturers of graphic products - for example printing companies with a pre-press stage, the actual printing stage and a post-press stage - there is a constant desire to improve product quality while maintaining or even increasing production speed, especially when processing a large number of different printing materials, for example paper types of different thicknesses. Technical task

[0009] It is therefore an object of the present invention to provide an improvement over the prior art which, in particular, makes it possible to process printing materials with different properties in a high-quality and highly productive manner using the pocket folding process. Inventive solution to the problem

[0010] This object is achieved according to the invention by a device according to claim 1 and a method according to claim 17.

[0011] Advantageous and therefore preferred developments of the invention emerge from the subclaims as well as from the description and the drawings.

[0012] A device according to the invention for folding sheets, in particular a pocket folding device or a pocket folding unit, comprising two folding rollers with a common folding nip, which has an inlet side and an outlet side, comprising a first insertion shaft with a first insertion level for an optionally insertable folding pocket with a folding pocket mouth, wherein the first insertion shaft is designed such that the folding pocket mouth of the optionally inserted folding pocket is arranged on the inlet side of the folding nip, and comprising a second insertion shaft with a second insertion level for an optionally insertable folding pocket with a folding pocket mouth, is characterized in that the second insertion level is designed with an incline to the first insertion level and in that the second insertion shaft is designed such that the folding pocket mouth of the optionally inserted folding pocket is arranged on the inlet side of the folding nip.

[0013] A method according to the invention for folding sheets, wherein a device according to the invention is used, is characterized in that for a first folding job the optionally insertable folding pocket is inserted into the first insertion slot and that for a second folding job the optionally insertable folding pocket is inserted into the second insertion slot. Advantageous embodiments and effects of the invention

[0014] The invention advantageously enables printing substrates with different properties to be processed with high quality and high productivity using the buckle folding process. The invention is used, for example, in buckle folding units of industrial folding machines.

[0015] When different printing substrates are processed one after the other in folding machines, i.e. when folding jobs are carried out one after the other, it can happen that certain printing substrates and therefore a specific folding job cause / cause problems. These problems can arise in particular with the shingled feed of the sheets and the shingled folding of the sheets in the folding pockets, as the sheets then pass each other at least partially in the area of ​​the respective folding pocket mouth. Extensive research has therefore been carried out to find ways of avoiding these problems. This has led to the solution according to the invention. The folding result can therefore be significantly improved if, for specific folding jobs, a slide-in tray which is inclined rather than the “standard” slide-in tray is used. The inclination orAt this changed angle, consecutive sheets that are shingled relative to each other (sheets in a shingled stream) also pass each other at different angles, thus avoiding or at least reducing the problem. The optimal angle for the inclination of the folding pocket ultimately determined during the investigations represents a compromise: if a folding pocket is tilted more sharply, a sheet to be folded enters it more smoothly and thus more efficiently. On the other hand, however, this sheet exits the folding pocket more steeply and thus more poorly.

[0016] Furthermore, the investigations revealed that it can be advantageous to offset the first two or three folding rollers of the roller frame (i.e., not the upstream roller) by a few millimeters, particularly upwards, compared to a prior art device not according to the invention. This improves the entry angle of the sheet to be folded from a folding gap between the offset folding rollers into the downstream folding pocket. Terms used in the application

[0017] The sheets to be folded enter and exit the respective folding pocket mouth (or mouth for short), one after the other or as a shingled stream.

[0018] The term "inclination" in this application with regard to insertion planes should be understood as follows: A insertion plane with an inclination to another insertion plane forms an angle other than zero with the other insertion plane; or in other words: the two insertion planes are not parallel to each other.

[0019] The term "optional" in this application with regard to folding pockets is to be understood as follows: Depending on the folding job to be processed with the device, e.g. thin or thick printing material to be folded, a choice is made (automatically or by the operating personnel) as to whether a folding pocket for folding is arranged in the first insertion slot or in the second insertion slot. During folding, the folding pocket is therefore arranged in the selected insertion slot. Sheet diverters can also be arranged optionally, i.e. they are arranged where no folding pockets are optionally arranged. Thus, for example, either a folding pocket or alternatively a sheet diverter is arranged, preferably in each case in a insertion slot.

[0020] The folding pocket that can be inserted and removed again at will into the first insertion slot (or slot for short) and the folding pocket that can be inserted and removed again at will into the second insertion slot (or slot for short) are preferably of identical construction and in particular the same folding pocket; alternatively, there can be two folding pockets of the same or at least similar type. Further developments of the invention

[0021] Preferred developments of the invention as a device (hereinafter referred to as "developments") are described below. These can also be combined with one another, where technically possible.

[0022] A further development can be characterized in that the optionally insertable folding pocket is arranged either in the first insertion slot or in the second insertion slot, ie it has been inserted and can be removed from there again.

[0023] A further development can be characterized in that the device comprises a roller mill with the two folding rollers and at least two additional folding rollers, preferably with a total of six, seven, eight, or nine folding rollers. A further development can be characterized in that the roller mill has a zigzag arrangement, i.e., the connecting lines between the rotation axes of the folding rollers of the roller mill together form a zigzag line.

[0024] A further development can be characterized in that the device comprises at least one insertion shaft on a first side of the roller mill and at least one insertion shaft on the opposite second side of the roller mill. A further development can be characterized in that the device comprises at least two insertion shafts on a first side of the roller mill and at least two insertion shafts on the opposite second side of the roller mill. A further development can be characterized in that the device comprises at least three insertion shafts on a first side of the roller mill and at least three insertion shafts on the opposite second side of the roller mill. A further development can be characterized in that the insertion shafts or their insertion levels are designed without an incline to the first insertion level, ie all insertion shafts are parallel to one another.

[0025] A further development can be characterized in that the device comprises successive insertion shafts at positions P1 to Pn in the transport direction of the sheets through the roller mill, where n≥2 and where odd n are on the first side and even n are on the second side, and that the first insertion shaft and the second insertion shaft are located at position P2. The insertion shafts at the positions are preferably designed and / or oriented such that the mouth of a respectively selectively inserted folding pocket lies on the inlet side of a folding gap between two folding rollers and at the same time lies on the outlet side of a folding gap between two folding rollers.

[0026] A further development can be characterized by the optional arrangement of a sheet deflector in or near an insertion slot at position P1. In this case, no folding pocket is located at position P1.

[0027] A further development can be characterized in that the optionally insertable folding pocket is arranged in the second insertion shaft at position P2 and that optionally no folding pocket is / are arranged in the further insertion shaft or in the further insertion shafts on the second side, i.e. at least at position P4; or in other words: optionally only one folding pocket is in operation on the second side. A further development can be characterized in that optionally a sheet switch or sheet switches are arranged in the further insertion shaft or in the further insertion shafts on the second side. A further development can be characterized in that at least two sheet switches are coupled to one another in such a way that they can be inserted into and removed from the device together.

[0028] A further development can be characterized in that the further position or the further positions on the second side, i.e. at least position P4, comprise a respective further insertion shaft with a respective further insertion level and in that these further insertion levels are each designed with an inclination to the first insertion level. A further development can be characterized in that these further insertion levels are each designed with an inclination that is the same as that of the second insertion level. A further development can be characterized in that these further insertion levels are each designed with an inclination that is different from that of the second insertion level; for example, it can be provided that a first folding pocket on the second side is inclined by 17° or 18°, a following second by 19° and a further following third by 20° (in each case with reference to the first insertion level).

[0029] A further development can be characterized in that the further position or the further positions on the first side, i.e. at least position P1, comprise a respective further insertion slot with a respective further insertion level and in that these further insertion levels are each designed with an incline to the first insertion level. The term “inclination to the first insertion level” also includes an incline to a plane parallel to the first insertion level. A further development can be characterized in that these further insertion levels are each designed with an incline that is the same as that of the second insertion level. A further development can be characterized in that these further insertion levels are each designed with an incline that is different from that of the second insertion level.

[0030] A further training course can be characterized by an inclination between 15° and 20°. A further training course can be characterized by an inclination of 17°.

[0031] Preferred developments of the invention are described below as methods (hereinafter referred to as "developments"). These can also be combined with one another where not technically mutually exclusive.

[0032] A further development can be characterized in that the sheets are fed to the device in a shingled stream and that at least one first sheet runs out of one folding pocket while a subsequent second sheet runs into the folding pocket.

[0033] A further development can be characterized in that a section of the second arch on entry runs past a section of the first arch on exit.

[0034] The features and combinations of features disclosed in the above sections Technical Field, Invention and Further Developments as well as in the following section Exemplary Embodiments represent - in any desired combination with one another - further advantageous developments of the invention. Embodiments of the invention and figures

[0035] The Fig. Figures 2 to 4 show preferred embodiments of the invention and its further developments. Corresponding features are provided with the same reference numerals in the figures. Recurring reference numerals have been partially omitted for clarity.

[0036] The Fig. 1 and Fig. 2 shows a schematic representation of a sectional view of the same device according to the prior art.

[0037] The Fig. 3 to 6 each show a schematic representation of a sectional view of a preferred embodiment of the device according to the invention.

[0038] The Fig. 1 and Fig. The technical features shown in Figure 2 are also preferably present in the respective embodiments of the device according to the invention according to Fig. 3 to 6 are present and are therefore not explained in detail there.

[0039] Fig. 1 shows a device 1 with a transport or processing direction 2 for sheets 3 to be processed, i.e., folded, which are preferably fed to the device 1 as an imbricated stream. The device 1 comprises a folding roller frame 10 with a plurality of successively arranged folding rollers 11, each with a rotation axis 12. The folding roller frame 10 defines a first side 13 (exemplarily on the left in the figure) and a second side 14 (exemplarily on the right in the figure). The connecting lines 15 between the rotation axes 12 form a zigzag arrangement 16. The device 1 is preferably part of a folding machine 50 or a folding unit 51.

[0040] Fig. 1 shows a first folding roller 20, a second folding roller 21 arranged downstream of the first folding roller, and further folding rollers 22 of the folding roller frame 10. The first folding roller 20 and the second folding roller 21 form a folding nip 23; as do respective pairs of the further folding rollers. The folding nip 23 defines an inlet side 24 and an outlet side 25, with a sheet 3 to be folded entering the folding nip 23 on the inlet side 24 and exiting again on the opposite outlet side 25 of the folding nip 23. The folding roller frame 10 also includes an upstream roller 26.

[0041] Fig. 2 shows, on the second side 14, a first insertion slot 30 with a first insertion level 31, as well as further insertion slots 34 with a further insertion level 35 on the first side 13, and further insertion slots 36 with a further insertion level 37 on the second side 14. A folding pocket 40 with a folding pocket mouth 41 for a specific folding job can be selectively inserted into each insertion slot and removed again (direction 60), with the folding pocket mouth 41 being positioned near a folding gap. A sheet 3 to be folded enters and exits the respective folding pocket through the folding pocket mouth 41. Each folding pocket 40 preferably has an adjustable folding pocket stop 42. The insertion slots can be located at the numbered positions P1 to P6, which correspond to the respective folding gaps. Fig. 1, all six illustrated insertion slots or all six positions P1 to P6 are equipped with folding pockets 40. In Fig. 2, only two insertion slots at positions P2 and P3 are equipped with folding pockets 40; at the remaining positions P1 and P4 to P6, sheet switches 43 are arranged instead.

[0042] Fig. Figure 1 shows (only in sections for illustrative purposes) a sheet 4 with a section 5 entering a folding pocket 40 and a sheet 6 with a section 7 exiting the same folding pocket 40, with sections 5 and 7 passing each other during shingled folding. To prevent substrate-specific problems from arising during this process, particularly when consecutive sheets 3 pass each other, the invention additionally provides an inclined, second insertion slot. This and other inclined insertion slots are explained in the following figures.

[0043] In Fig. 3 shows that, in addition to the first insertion slot 30 with the first insertion level 31 in position P2, there is a second insertion slot 32 with a second insertion level 33 in position P2. The second insertion level 33 is inclined by the angle α relative to the first insertion level 31 (in the illustration, for example, inclined downwards), preferably by approximately 17°. Fig. 4 shows that a folding pocket 40 with a folding pocket mouth 41 is optionally inserted into the second insertion slot 32 for a specific folding job. Furthermore, a folding pocket 40 is also inserted in position P3 for the specific folding job, while optionally no folding pockets are present in the other insertion slots for the specific folding job; instead, optional sheet switches 43 are present. The two sheet switches at positions P4 and P6 are mechanically connected to one another via a coupling 44 and can thus be inserted and removed together.

[0044] It should be noted here that the insertion slots of the folding pockets in actual folding devices are usually longer than shown, and that therefore the inclined insertion slot 30 and the inclined folding pocket 40 in position P2 can cross the insertion slots 36 in positions P4 and P6. In such a case, no folding pockets 40 can be present in positions P4 and P6 if a folding pocket 40 is present in the inclined insertion slot 32 in position P2.

[0045] In Fig. 5 shows that in positions P4 and P6, in addition to the non-inclined insertion slots, inclined insertion slots 36 with inclined insertion levels 37 can also be present. The inclination α1 can be the same or different from the inclination α. ​​Furthermore, in Fig. 6 that inclined insertion slots 34 with inclined insertion levels 35 can also be present on the opposite side in positions P1, P3, and P5. The inclination α2 and / or α3 can be the same or different from the inclination α and / or α1. If multiple insertion slots are present on one of the two sides 13 and 14, they can, in particular, be parallel to one another.

[0046] It may be provided that the Fig. 4 shown folding rollers 17 (all three or only the two upper ones) compared to the arrangement in Fig.1 can be arranged offset upwards by a few millimeters, i.e., preferably already during assembly and permanently. Or, to put it another way: the group of two or three folding rollers 17 is spaced from the group of other folding rollers of the roller frame at a distance that differs from the distance between the respective folding rollers, preferably being greater. This advantageously changes the angle at which a sheet 3 to be folded enters the inclined folding pocket 40 and, at the same time, the angle at which it exits again. List of reference symbols 1 device 2 Transport direction 3 arches, (scaled) stream from arches 4 incoming sheets 5 Section of the incoming sheet 6 expiring bow 7 Section of the outgoing arc 10 folding roller mill 11 folding rollers 12 rotation axes of the folding rollers 13 first page 14 second page 15 connecting lines 16 Zigzag arrangement or zigzag line 17 folding rollers 20 first folding roller 21 second folding roller 22 additional folding rollers 23 folding gap(s) 24 Inlet side of the folding gap 25 Outlet side of the folding gap 26 upstream roller 30 first slot 31 first shelf level 32 second slot 33 second shelf level 34 additional slots on the first side 35 additional shelf levels 36 additional slots on the second side 37 additional shelf levels 40 folding pockets 41 Folding pocket mouth 42 (adjustable) folding pocket stop 43 curved switches 44 couplers for curved switches 50 folding machine 51 folding unit 60 Direction when pushing in and out P1-Pn positions 1 to n α Inclination(s) or angle α1 inclination(s) or angle α2 inclination(s) or angle α3 inclination(s) or angle

Claims

[1] Device for folding sheets, comprising two folding rollers (20, 21) with a common folding gap (23), which has an inlet side (24) and an outlet side (25), comprising a first insertion shaft (30) with a first insertion level (31) for an optionally insertable folding pocket (40) with a folding pocket mouth (41), wherein the first insertion shaft (30) is designed such that the folding pocket mouth (41) of the optionally inserted folding pocket (40) is arranged on the inlet side (24) of the folding gap (23), and comprising a second insertion shaft (32) with a second insertion level (33) for an optionally insertable folding pocket (40) with a folding pocket mouth (41), characterized bythat the second insertion plane (33) is designed with an inclination (α) to the first insertion plane (31) and that the second insertion shaft (32) is designed such that the folding pocket mouth (41) of the optionally inserted folding pocket (40) is arranged on the inlet side (24) of the folding gap (23). [2] Device according to claim 1, characterized by that the optionally insertable folding pocket (40) is arranged either in the first insertion slot (30) or in the second insertion slot (32). [3] Device according to claim 1 or 2, characterized by that the device (1) comprises a roller mill (10) with the two folding rollers (21, 22) and at least two further folding rollers (22). [4] Device according to claim 3, characterized bythat the device (1) comprises at least one insertion shaft (34) on a first side (13) of the roller mill (10) and at least one insertion shaft (30, 36) on the opposite second side (14) of the roller mill (10). [5] Device according to claim 4, characterized by that the insertion slots (34, 36) or their insertion levels (35, 37) are designed without an inclination to the first insertion level (31). [6] Device according to one of the preceding claims 3 to 5, characterized by that the device (1) comprises, in the transport direction (2) of the sheets (3) through the roller mill (10), successive insertion shafts (30, 32, 34, 36) at positions P1 to Pn, where n≥2 and where odd n is on the first side (13) and even n is on the second side (14), and that the first insertion shaft (30) and the second insertion shaft (32) are at position P2. [7] Device according to claim 6, characterized bythat a curved switch (43) is optionally arranged in or near a slot (34) at position P1. [8] Device according to one of the preceding claims 6 or 7, characterized by that the optionally insertable folding pocket (40) is arranged in the second insertion shaft (32) at position P2 and that in the further insertion shaft (36) or in the further insertion shafts (36) on the second side (14), i.e. at least at position P4, optionally no folding pocket(s) is / are arranged. [9] Device according to claim 8, characterized by that in the further insertion shaft (36) or in the further insertion shafts (36) on the second side (14) optionally a curved switch (43) or curved switches (43) are arranged. [10] Device according to claim 9, characterized by that at least two curved switches (43) are coupled (44) to one another in such a way that they can be inserted and removed together into the device (1). [11] Device according to one of the preceding claims 6 to 10, characterized by that the further position or the further positions on the second side (14), i.e. at least position P4, comprise a respective further insertion slot (36) with a respective further insertion level (37) and that these further insertion levels (37) are each designed with an inclination (α1) to the first insertion level (31). [12] Device according to claim 11, characterized by that these further insertion levels (37) are each formed with an inclination (α1) which is the same as that of the second insertion level (33). [13] Device according to claim 11, characterized by that these further insertion levels (37) are each formed with a different inclination (α1) compared to the second insertion level (33). [14] Device according to one of the preceding claims 6 to 13, characterized bythat the further position or the further positions on the first side (13), i.e. at least position P1, comprise a respective further insertion slot (34) with a respective further insertion level (35) and that these further insertion levels (35) are each formed with an inclination (α2) to the first insertion level (31). [15] Device according to claim 14, characterized by that these further insertion levels (35) are each formed with an inclination (α2) which is the same as that of the second insertion level (33). [16] Device according to claim 14, characterized by that these further insertion levels (35) are each formed with a different inclination (α2) compared to the second insertion level (33). [17] Method for folding sheets, wherein a device (1) according to one of the preceding claims is used, characterized bythat for a first folding job the optionally insertable folding pocket (40) is inserted into the first insertion slot (30) and that for a second folding job the optionally insertable folding pocket (40) is inserted into the second insertion slot (32). [18] Method according to claim 17, characterized by that the sheets (3) are fed to the device (1) in an imbricated stream and that a first sheet (6) runs out of at least one folding pocket (40) while a subsequent second sheet (4) runs into the folding pocket.

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