EP0183862B1 - 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 can be assumed that paper slitting will occur to a considerable extent, especially when slitting, and this must be removed.

For example, it is known from DE-B-217 176 to remove the resulting dust during the longitudinal cutting of a paper web by arranging a suction chamber in the area of the longitudinal cutter between the cutting discs and a pressure roller, through which paper dust accumulating during the longitudinal cutting occurs directly from the Longitudinal cutting area is suctioned off.

From DE-A-21 64 554 it is known to remove paper dust accumulating in the longitudinal cutting of a paper web in such a way that knife disks penetrate into the peripheral slots of a roller body in order to carry out the longitudinal cutting process in the penetration area. so that dust can be extracted through the circumferential slots during slitting.

From DE-B-303 958 it is known to remove paper dust accumulating during the longitudinal cutting of a paper web by blowing off or suctioning off the dust.

Finally, it is known from US-A-3 388624, after the slitting process. Let the interface run over a suction chamber 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 in order to remove dust accumulated along the respective longitudinal edges of the interface of the paper web.

DE-A-3219774 describes a dust absorbing device for lye cutters. It is extracted directly from the cutting point.

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 in the area of the longitudinal edges of the paper web at the longitudinal interface 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 optimum 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 partially limited by guide tables for the paper web arranged in front of and below 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, here designed as a suction table, in which longitudinal slots are provided along the longitudinal interfaces of the paper web are formed, which 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 thereby with the longitudinal interfaces over the mentioned longitudinal slots, this leads to a separation of the longitudinal edges created by 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, which is 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 respective effective breaking bar edge being connected to the suction chamber via a suction opening located in the hollow box, so that air can only be sucked off through the specific suction channel and thus dust can be effectively removed in the area of the breaking bar edge.

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 area 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. 4b 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.
• Fig. 1 zeigt schematisch einen Teil einer Anlage, welche in Aufeinanderfolge Bearbeitungsstationen zeigt, in denen auf unterschiedliche Weise auf die Papierbahn eingewirkt wird. Insbesondere werden verschiedene Entstaubungsmassnahmen vorgenommen.

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.
• 2 shows a breaker 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 plant 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.

• In Fig. 2 ist die in der Station A befindliche Brechleiste 52 mit integrierter Staubabsaugung dargestellt. Wie der Fig. 2 zu entnehmen ist, läuft die Papierbahn P von einer Walze 54 zur Brechleiste 52, wo die Papierbahn mit einer Umlenkung ( a) um eine Kante 56 der Brechleiste 52 geführt ist.

The individual stations are now described below with reference to FIGS. 2 to 6:

• 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 around an edge 56 of the break bar 52 with a deflection (a).

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 (a).

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. There is a guide plate 76 in the direction of movement of the paper web in front of the rotary knives and behind the rotary knives there is a guide table designed as a suction table 78. 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 longitudinal cutting, this is done in three ways, namely by means of a first suction device 80 located directly below the lower knife 74, a second suction device 82 adjoining it, located above the suction table 78 and behind the upper knife 72, and one below the suction table 78 in the direction of movement third suction device 84 located on 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 entrains a large part of the dust that occurs in the immediate area of the knives when slitting.

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 are schematically closed on the left side see, as well as the suction table 78 adjoining it in the direction to the right, ie in the direction of travel of the paper web, with the suction box 110 underneath. On the right-hand side of the suction table, the already mentioned pair of pulling rolls 118, which are pulling rolls, are connected 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 superimposed paper webs if the paper web with the interface is continuously moved over the longitudinal slot 114 and air is sucked through the longitudinal slots into the suction box, which air is not only deforming Has an effect on the paper sheets in the longitudinal section area, but also has an effect in that residual dust still present, favored by the fanning out, is drawn off into the suction box.

Even when cutting the paper web cross-wise, dust removal must be carried out, although to a lesser extent. A suction device in this regard 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 in a self-sharpening manner 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 mentioned gap between the paper giant 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 installation 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 blowing air downwards in the immediate knife area, then by blowing from the bottom up, ie suction upwards, and finally by suction downwards. especially in the longitudinal section of the paper web, the paper dust accumulated during cutting is removed in an optimal manner. In the case of the latter extraction, the interfaces of the paper web run through the aforementioned longitudinal slots 114 via the suction table 78. In addition to dust extraction, 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 be designed as rotary brushes, for example, which are arranged directly above the longitudinal slots.

The vacuum in 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 from 250 to 840 millibars. The best results are achieved in this area, although it is possible to set the vacuum values 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 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).

2. Device according to claim 1, characterised in that between the two arrangements (40, 84) for sucking away paper dust according to claim 1, a further third arrangement (82) is arranged for sucking away paper dust in such manner that a blowing arrangement (104) is arranged opposite to this at the longitudinal cut zones on the other side of the paper web (P).

3. Device according to claims 1 and 2, characterised in that the first arrangement (80) is arranged beneath the paper web (P) the second arrangement (84) is likewise arranged beneath the same and the third arrangement (82) is arranged above the paper web.

4. Device according to claim 1, characterised in that the first arrangement (80) for sucking away paper dust forms beneath the lower longitudinal cutting blade (75) a suction chamber (102) which is partially bounded by guide table (76, 78) for the paper web (P) arranged before and after the longitudinal cut zone (a) in the direction of motion of the paper web (P).

5. Device according to claim 1, characterised in that the second arrangement (84) for sucking away paper dust comprises the guide table (78) following the longitudinal cut zone (a) and formed as a suction table, in which longitudinal slots (114), in communication with a suction chamber (110) are arranged along the longitudinal cut zones of the paper web (P).

6. Device according to claim 2, characterised in that the blowing arrangement (104) and the third arrangement (82) for sucking away paper dust are each arranged on one side of slots (77) which are formed in the guide table (78) following the longitudinal cut zone (a).

7. Device according to claim 5, characterised in that the longitudinal slots (114) have inwardly and outwardly curved edges (79) transversely of the direction of motion of the paper web (P).

8. Device according to claim 1 and 2, characterised in that in the region of the transverse cutting blade (122) above or beneath the paper web (P) a fourth arrangement (125, 126, 128) is arranged for sucking away paper dust.

9. Device according to claims 1, 2 and 8, characterised in that in the direction of motion of the paper web (P) before the longitudinal cut zone (a) in the region of a deflector rail edge (56) a fifth arrangement (52) for sucking away paper dust is arranged.

10. Device according to claim 9, characterised in that the fifth arrangement (52) for sucking away paper dust is integrated into the deflector rail in such manner that before the deflector rail edge (56) in the direction of motion of the paper web a suction channel (66) is arranged which communicates with a suction chamber (58) formed within the deflector rail.

11. Device according to claim 10, characterised in that two deflector rail edges (56; 57) are formed from a material block (64) which is releasably mounted on a hollow box (58) forming the suction chamber, and in that adjacent each deflector rail edge (56;57) a suction channel (66; 67) is arranged of which the suction channel (66) neighbouring the effective deflector rail edge (56) communicates via a suction opening (68) located in the hollow box (58) with the suction chamber.

12. Device according to claim 1, characterised in that a sixth arrangement (136, 138, 140, 142) is provided for sucking away paper dust in the region of a transport path of a paper ream (R) in such manner that a suction chamber (136) communicates via corresponding suction openings (142) with at least one peripheral edge of the paper ream (R).

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