EP0183862A1 - Apparatus for preparing format papers with a low dust content - Google Patents

Abstract

1. Device for the manufacture of low dust format papers by longitudinal and transverse cutting of a paper web (P) comprising at least one arrangement (80, 84) for sucking away of paper dust arising during processing of the paper, characterised by a first arrangement (80) for sucking away paper dust directly in the longitudinal cutting region (a) and a subsequent second arrangement (84) for sucking away paper dust in the region of the longitudinal cut zones of the paper web (P).

Description

The invention relates to a device for producing low-dust format paper by longitudinally and transversely cutting a paper web, with at least one device for suctioning off paper dust accumulating when it acts on the paper.

Format papers, in particular as copy paper, are increasingly required. It is important that these format papers are largely dust-free. It is generally known that when these format papers are produced from a continuous paper web by longitudinal and transverse cutting, paper dust is produced to a considerable extent in particular if the paper web used for this purpose has been produced from waste paper components. It must be assumed that paper dust is produced to a considerable extent, especially when slitting, and this must be removed. For example, it is known from DE-PS 217 176 to remove the resulting dust when slitting a paper web in such a way that a suction chamber is arranged in the area of the slitter between knife disks and a pressure roller, through which paper dust accumulating during slitting is obtained directly from the slitting area is suctioned off.

From DE-OS 21 64 554 it is known to eliminate paper dust accumulating in the longitudinal cutting of a paper web such that knife disks penetrate into the circumferential slots of a roller body in order to carry out the longitudinal cutting process in the penetration area. These circumferential slots are in communication with a suction chamber located within the roller body, so that dust which is produced during the longitudinal cutting can be extracted through the circumferential slots.

From DE-PS 303 958 it is known to remove paper dust accumulating during the longitudinal cutting of a paper web in that the dust is blown off or suctioned off.

Finally, it is known from US Pat. No. 3,888,624 to let the interface run over a suction chamber after the longitudinal cutting process in such a way that one cut side of the paper web on one side and the other cut side of the paper web on the other side of the suction chamber runs past suction slots to remove dust accumulated along the respective longitudinal edges of the interface of the paper web.

The known devices for removing dust accumulating during the cutting of a paper web cannot be used satisfactorily for the production of low-dust format paper, so that there is a need for a considerable improvement in this regard.

The invention is therefore based on the object of providing a device for producing format papers by cutting lengthwise and transversely of a paper web, with which format papers which are largely free of dust can be produced in the simplest possible way.

This object is achieved according to the invention by a first device for suctioning paper dust directly in the longitudinal cutting area and a downstream second device for suctioning paper dust in the area of the longitudinal interfaces of the paper web.

According to this solution, the suction of the paper dust in connection with the slitting is not limited to the slitting area itself, but to a location immediately afterwards as a supplementary suction directly in the area of the longitudinal interfaces. This leads to an improved removal of the paper dust, which is caused by the slitting.

With regard to a further optimization of the dust removal due to the longitudinal cutting, there is a further third device for suctioning paper dust between the two aforementioned devices for suctioning paper dust in such a way that opposite to the suction device at the longitudinal interfaces on the other side of the paper web, ie a blowing device is arranged opposite the suction device. This blowing device blows paper dust located at the longitudinal interface in the region of the longitudinal edges of the paper web to the other side of the paper web, where the suction device is located, in order to suck off the blown-off dust. It is advantageous that the blowing process separates the longitudinal edges resulting from the longitudinal cut and thus enables optimal dust removal in addition to the other two dust removal measures.

It has turned out to be particularly advantageous if the first device for suction of paper dust is below the paper web, the second device for suction of paper dust is also below the paper web and the third device for suction of paper dust is above the paper web. This mutual arrangement of the suction devices leads to an optimization of the paper dust removal.

The first device for suctioning paper dust expediently forms a suction chamber below the lower longitudinal cutting knives, which is partly limited by guide tables for the paper web arranged in front of and under the longitudinal cutting point in the running direction of the paper web. These guide tables therefore advantageously fulfill a double function. In an advantageous embodiment, the second device for suctioning paper dust, which is connected downstream of the longitudinal cutting point, comprises the guide table already mentioned, designed here as a suction table, in which longitudinal slots are formed along the longitudinal interfaces of the paper web and are connected to a suction chamber. It is particularly advantageous if these longitudinal slots have edges which run inwards and downwards transversely to the direction of movement of the paper web. While the paper web moves over the suction table and with the longitudinal interfaces over the mentioned longitudinal slots, this leads to a separation of the longitudinal edges resulting from the longitudinal cut in the sense of an optimal dust removal. In particular, this constructive design of the longitudinal slots has an advantageous effect if several superimposed paper webs are cut and the longitudinal slots cause the superimposed paper webs to be fanned out in the area of the longitudinal cuts, so that dust located between the paper webs is optimally removed and, moreover, that after the longitudinal cutting at the interfaces adhesive longitudinal edges of the paper webs are separated.

A particularly advantageous structural design results if not only the aforementioned longitudinal slots for the second device for suctioning paper dust are formed in the aforementioned suction table, but also slots that lie between the blowing device and the third device for suctioning paper dust, so that dust is also preferably removed in the area of the longitudinal intersections.

In addition to the devices for suctioning paper dust already mentioned, a fourth device for suctioning paper dust is expediently located in the area of the cross-cutting knife above or below the paper web, preferably below the paper web.

Before slitting, the paper web is often guided along the edge of a breaking bar. When the paper web is deflected and straightened there, paper dust also arises, which can be removed by a fifth device provided there for suctioning paper dust. This device is preferably designed to be integrated with the crushing bar in such a way that a suction channel is arranged in the direction of movement of the paper web in front of the crushing bar edge, said suction channel being connected to a suction chamber arranged inside the crushing bar. This avoids the need to install this paper dust extraction device as a separate device.

A material block is advantageously used, on which two edges of the breaker bar are formed. This block of material is detachably attached to a hollow box forming a suction chamber, so that after one edge of the breaking bar has worn out, the other breaking bar edge can be used after twisting the block of material. For this purpose, a suction channel is provided next to each breaking bar edge, the suction channel adjacent to the respectively effective breaking bar edge being connected to the suction chamber via a suction opening located in the hollow box, and thus only by air is extracted from the particular suction channel and dust can thus be effectively removed in the area of the edge of the crowbar.

Finally, for further optimization of the paper dust removal, a sixth device for suctioning paper dust is provided, specifically in the area of the transport path of a paper giant, such that a suction chamber is preferably arranged below the transport path for the paper giant and is connected to the edge region of the paper giant via corresponding suction openings , so that air can be drawn through this edge area from this suction chamber. The resulting air flow sucks away any remaining dust, so that ultimately largely dust-free format paper can be removed at the end of a system for producing format paper.

• Fig. 1 in schematischer Seitenansicht eine Anlage zum Herstellen von Formatpapier mit den einzelnen Bearbeitungsstationen;
• Fig. 2 eine Brechleiste mit integrierter Staubabsaugung;
• Fig. 3 eine Schnittansicht durch eine Längsschneidevorrichtung mit drei verschiedenen Absaugeinrichtungen;
• Fig. 4a vergrößert herausgezeichnet eine schematische Schnittansicht einer der in Fig. 3 dargestellten Absaugeinrichtungen;
• Fig. 4 b eine Querschnittsansicht entlang der Schnittlinie b-b in Fig. 4a;
• Fig. 5 eine Querschnittsansicht durch den Querschneidebereich der Anlage mit einer Staubabsaugeinrichtung; und
• Fig. 6 eine Querschnittsansicht durch eine Transportstation der Anlage gemäß Fig. 1 mit einer Staubabsaugeinrichtung.

Further details, features and advantages of the invention result from the following description of the exemplary embodiments shown purely schematically in the drawings. It shows:

• Figure 1 is a schematic side view of a system for producing format paper with the individual processing stations.
• Figure 2 is a break bar with integrated dust extraction.
• 3 shows a sectional view through a longitudinal cutting device with three different suction devices;
• 4a shows a schematic sectional view of one of the suction devices shown in FIG. 3 on an enlarged scale;
• 4b shows a cross-sectional view along the section line bb in FIG. 4a;
• 5 shows a cross-sectional view through the cross-cutting area of the installation with a dust extraction device; and
• FIG. 6 shows a cross-sectional view through a transport station of the system according to FIG. 1 with a dust extraction device.

Fig. 1 shows schematically a part of a system which shows, in succession, processing stations in which the paper web is acted on in different ways. In particular, various dedusting measures are taken.

1 shows from left to right a station A in which the paper web is guided past a break bar. This is followed by a station B, in which, if desired, the paper web is perforated through a rotary hole. This is followed by the longitudinal cutting of the paper web in a station C. The paper web is cross-cut in a subsequent station D, which is followed by a sorting switch E and a collecting station F, where the cut paper sheets are sorted or stacked. In the last station G, the stacked sheets of paper are transversely transported.

Below are now based on _F ig. 2 to 6 describe the individual stations:

2 shows the crushing bar 52 located in station A with integrated dust extraction. As can be seen in FIG. 2, the paper web P runs from a roller 54 to the break bar 52, where the paper web is guided with a deflection (O () around an edge 56 of the break bar 52.

The crushing bar consists of a hollow box 58, in which a suction nozzle 60 is fastened on the side facing away from the breaking edge 56, to which suction nozzle 60 a hose 62 is fastened.

The breaking edge 56 is located on a block 64 which is fastened on the side of the hollow box 58 facing away from the suction nozzle 60. In the immediate area of the breaking edge 56 and in the running direction of the paper web P in front of the breaking edge 56 there is a suction channel 66 in block 64, which is aligned with a suction opening 68 in the hollow box 58. Two suction channels 66, 67 are provided in a symmetrical arrangement, so that the block 64 can be changed in position so that after the breaking edge 56 has been worn, the symmetrically arranged breaking edge 57 can be used.

According to the double arrow 69, the entire crushing bar 52 can be pivoted back and forth about the central axis M of the roller 54 to a specific deflection angle (cK).

When suction is carried out through the hose 62, an air flow results according to the arrows shown from the area immediately in front of the breaking edge 56, through the suction channel 66, the suction opening 68, the hollow box 58 into the suction nozzle 60, so that more accumulates in the area of the breaking edge Dust is entrained with the air flow and discharged.

3, station C is shown in more detail. An upper knife 72 and a lower knife 74 are rotatably mounted in a frame 70 of this station, these knives being designed as circular knives which are arranged parallel to one another in the direction of their axis of rotation, an annular cutting edge 75 of the lower knife 74 and an annular cutting edge 73 of each Interacting upper knife 72 and overlap each other in a slitting area a. The axes of the circular knives 72, 74 are aligned parallel and one above the other perpendicular to the direction of movement of the paper web. In the movement direction of the paper web before the rehmessern _D there is a guide plate 76 and downstream of the rotary blades designed as a suction table 78 management table. The paper web runs continuously over the guide plate 76 and the suction table 78, with the aforementioned knife cutting the paper web lengthways. With this slitting, paper dust develops, which should be removed as completely as possible. In the large area of the longitudinal cutting, this is done in three ways, namely by means of a first suction device 80 located directly below the lower knife 74, and a subsequent suction device 80 above the suction table 78 and second suction device 82 located behind the upper knife 72, and a third suction device 84 located below the suction table 78 in the direction of movement of the paper web behind the second suction device 82.

For the first suction device 80 there are a row of suction openings 88 in an L-shaped lower knife bar 86 immediately below the lower knife 74, below which a suction box 9 is connected to the lower knife bar 86 and is connected to a hose 94 via a connecting piece 92.

The guide plate 76 already mentioned is fastened to the vertical leg of the lower cutter bar 86 above a bar 96. A cover plate 98 is fastened in the inner angular region of the lower cutter bar 86 in order to prevent dust nests from forming there. At the free end of the horizontal leg of the lower cutter bar 86, an end plate 100 is attached, which extends to the lower cutter 74 and thus forms a suction space 102 in the lower region of the lower cutter together with the lower cutter 74, the strip 96, the guide plate 76 and the suction table 78.

If air is sucked out through the hose 94, air is sucked in in the cutting area of the two knives, which air enters the suction box 90 via the suction opening 88 and from there into the hose 94. This air flow attacking a _G ross part of the dust with which occurs when slitting the immediate area of the blades.

The second suction device 82 has a blow pipe 104, which is located below the suction table 78. In the radiation area of this blow pipe 104 there are slots 77 in the suction table 78, through which the interfaces of the paper web extend after the longitudinal cutting, so that dust still at the interfaces is blown off and directed into the mouth opening 106 of an upper suction pipe 108.

The third suction device 84 is located behind the second suction device 82 with respect to the direction of movement of the paper web and essentially consists of a suction box 110 located below the suction table 78, to which a hose 112 is fastened. The suction box 110 is connected to elongated holes 114 in the suction table 78, through which the previously mentioned interfaces of the paper web run after the longitudinal cutting. In the direction of movement of the paper web, behind this third suction device 84, there is a further guide plate 116, to which a pair of pulling rollers 118 is connected.

A more detailed illustration of this third suction device can be seen in FIG. 4, in which FIG. 4b shows a section through an elongated hole 114 along the line b-b in FIG. 4a.

4a, the upper knife 72 and the lower knife 74 can be seen schematically on the left-hand side, and the suction table 78 adjoining them in the direction to the right, ie in the running direction of the paper web with the suction box 110 underneath. On the right side of the suction table is the already mentioned pair of pull rollers 118, which are pull rollers with which the paper web is pulled over the suction table.

As can be seen from FIG. 4b, the edges 79 of the longitudinal slots 114, which run transversely to the longitudinal direction of the longitudinal slots 114, are arched downward. The radius of this arching is about 3 mm when new and changes with increasing wear. The width of the longitudinal slots depends on the paper quality and is selected in exact coordination with the length of the longitudinal slots, the opening cross section of the longitudinal slots depending on the suction power and the available space in the machine. The longitudinal slots are located immediately behind the slitter, but must be arranged in the area of uniform tension in front of the cross knife.

A single, inherently rigid suction box or suction table does not necessarily have to be used. With a corresponding design, possibly with nested suction boxes, the longitudinal slots can be changed in the width direction in order to adapt to the respective sheet format.

As has already been described, the convex edges 79 serve to fan out the interface of one or more superposed paper webs when the paper web with the interface is moved continuously over the longitudinal slot 114 and is drawn through the longitudinal slots in the suction box air which has not only a deforming action on the paper sheets in the longitudinal sectional area, but the effect also an effect eststaub remaining _R, favored by fanning out to withdraw into the suction box.

Even when cutting the paper web cross-wise, dust removal must be carried out, although to a lesser extent. A corresponding suction device results from FIG. 5, where two identical knife drums 122 lying one above the other are rotatably mounted in a frame 120 in such a way that the knives 124 located therein come into contact with one another at a very specific point, so that at this point a cross cutting of the Paper web is done. Below the lower knife drum 122 there is a U-shaped bar 125 which surrounds at least the lower half of the lower knife drum 122 and thus forms a suction space 126. In the bar 125 below the suction chamber 126 suction openings 128 are formed, to which a suction device, not shown, is connected. In the direction of movement of the paper web from left to right in front of the two knife drums 122 there is also a guide plate 130 for the paper web, which in the rest enlarges the suction space 126 up to the top of the lower knife drum.

The running into the area of the cross cutters is stabilized by guiding the paper web over the suction table 78 already mentioned and described, so that a perfect cross cutting can take place.

Finally, during the removal, and in particular when the paper giant is transported transversely, a last edge dove extraction is carried out to remove residual dust. The relevant suction device results from FIG. 6. In FIG. 6, a cross conveyor belt 132 is shown on which the paper giant R rests. The paper giant R is laterally delimited by support bands 134 deflected about vertical axes, a small space remaining between the paper giant and the support bands. Underneath the conveyor belt 132 there is a suction box 136 with a suction nozzle 138 and a hose 140 adjoining it. On the side of the suction box 136 there are suction openings 142 which are connected to the gap between paper rolls R and the support belts 134. If suction is thus carried out through the hose 140, air is sucked in from the surroundings into the gap between the paper rolls R and the support belts 134 and from there into the suction box 136 in accordance with the arrows shown. Residual dust present at the edges of the paper giant is sucked off and removed by the resulting air flow.

When the paper web passes through the system shown in FIG. 1, the paper web P is guided past a break bar in station A and thereby undergoes a directional deflection. This action on the paper creates surface paper dust due to a certain amount of abrasion. The paper dust accumulated there is sucked off by the suction device integrated in the break bar 52 by an air flow, which is indicated in FIG. 2 by a series of three arrows.

After passing through station B, the paper web arrives in station C and there in the area of the slitter. In this area, triple suction takes place in interaction from above or from below, first by downward air flow in the immediate knife area, then by blowing from the bottom up, i.e. Vacuuming upwards, and finally by vacuuming downwards, in particular in the longitudinal section of the paper web, the paper dust accumulated during the cutting is optimally removed. In the latter suction, the interfaces of the paper web run through the longitudinal slots 114 mentioned above the suction table 78. In addition to the dust suction, this leads to a stabilization of the paper web. The suctioning of the dust in this area is additionally facilitated in that these elongated holes are arched transversely to the direction of movement of the paper web. In particular, if several superimposed paper webs are cut, the cut paper web is "opened" in the cutting area, so that the dust can also be removed from the inner area of the paper webs. Dust extraction can also be improved by brushes acting over the longitudinal slots. These can e.g. be designed as rotary brushes, which are arranged directly above the longitudinal slots.

The vacuum during the dust extraction in the area of the lower knives in the longitudinal and / or cross cutting area and / or on the suction table 78 can be maintained at cutting speeds between 100 to 400 m / min., Advantageously in the range of 250 to 840 millibars. In this area, the best results achieved, but it is possible to set values of the vacuum specified above the limit values.

After the longitudinal cutting, the cross cutting then takes place in the station D, where the suction already described takes place in the area of the lower knife in order to remove the paper dust which arises during the cross cutting.

In station G the paper giant R is transported away with the dust removal already described.

Claims (12)

1.Device for the production of low-dust shaped paper by longitudinally and transversely cutting a paper web, with at least one device for suctioning off paper dust arising when acting on the paper, characterized by a first device (80) for suctioning paper dust directly in the longitudinal cutting area (a) and one downstream second device (84) for suctioning paper dust in the area of the longitudinal interfaces of the paper web (P). 2. Device according to claim 1, character- ized in that between the two devices (40, 84) for suction of paper dust according to claim 1, a further third device (82) for suction of paper dust is arranged such that opposite to this A blowing device (104) is arranged on the longitudinal interfaces on the other side of the paper web (P). 3. Apparatus according to claim 1 and 2, characterized in that the first device (80) below the paper web (P), the second device (84) is also arranged below the same and the third device (82) above the paper web. 4. The device according to claim 1, character- ized in that the first device (80) for suction of paper dust below the lower longitudinal cutting knife (75) forms a suction chamber (102), partially in front of and behind in the direction of travel of the paper web (P) the longitudinal cutting point (a) arranged guide tables (76, 78) for the paper web (P) is limited. 5. The device according to claim 1, characterized in that the second device (84) for suctioning paper dust comprises the guide table (78) connected downstream of the longitudinal cutting point (a) and designed as a suction table, in which along the longitudinal interfaces of the paper web (P) Longitudinal slots (114) are formed which are connected to a suction chamber (110). 6. The device according to claim 2, character- ized in that the blowing device (104) and the third device (82) for suction of paper dust are arranged on one side of slots (77), which in the downstream of the longitudinal cutting point (a) Guide table (78) are formed. 7. The device according to claim 5, character- ized in that the longitudinal slots (114) transversely to the direction of movement of the paper web (P) have inwardly and downwardly curved edges (79). 8. The device according to claim 1, characterized in that a fourth device (125, 126, 128) for suctioning paper dust is arranged in the region of the cross-cutting knife (122) above or below the paper web (P). 9. The device according to claim 1, character- ized in that in the direction of movement of the paper web (P) in front of the longitudinal cutting point (a) in the region of a breaking bar edge (56) a fifth device (52) for suctioning paper dust is arranged. 10. The device according to claim 9, character- ized in that the fifth device (52) for suction of paper dust is integrated in the crushing bar such that a suction channel (66) is arranged in front of the crushing bar edge (56) in the direction of movement of the paper web is connected to a suction chamber (58) formed within the crushing bar. 11. The device according to claim 10, character- ized in that two breaker bar edges (56; 57) are formed by a block of material (64) which is releasably attached to a hollow box (58) forming the suction chamber, and that next to each A suction channel (66; 67) is arranged, of which the suction channel (66) adjacent to the effective breaking bar edge (56) is connected to the suction chamber via a suction opening (68) located in the hollow box (58). 12. The apparatus according to claim 1, character- ized in that a sixth device (136, 138, 140, 142) for suction of paper dust in the region of the transport path of a paper giant (R) is provided such that a suction chamber (136) over corresponding Suction openings (142) are connected to at least one edge area of the paper giant (R).

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