EP1516838B1 - Device for processing stacks of electrostatic rechargeable flat parts - Google Patents

Abstract

The apparatus advances a web lengthwise in a predetermined direction along a predetermined path. The web has a subdividing arrangement at a portion of the path, so that the web yields a succession of discrete stacks. The advancement device has a first unit at a second portion of the path upstream of the first portion, as seen in the direction, and a second unit at a third portion of the path downstream of the first portion, as seen in the direction. An electrostatic charging device is provided for the web. The device is located in the region of one of the units adjacent to a cutting device. The charging device is located between the subdividing arrangement and one the units. An endless band conveyor having an upper reach is arranged to support a portion of the multi-layer web.

Description

The invention relates to a device for processing a multi-layer electrostatically chargeable web, with at least one cutting device for cutting the multilayer material web into corresponding superimposed sheets, downstream of the cutting device located, an endlessly rotating conveyor belt assembly having conveyor for transporting the multilayer material web and one in the Conveying device adjacent to the cutting device arranged electrostatic charging device for electrostatic charging of the multilayer material web.

When transporting a multi-ply web or cut from it overlying sheets in the paper processing industry, for example, from one processing station to another, to a stack tray or a packaging machine, the sheets are due to accelerations or delays by the conveyors, branches u. Like. Particularly endangered. Especially at high accelerations and abrupt changes in direction of the Transport path can slip the superimposed arches in itself. Therefore, high demands are placed on the mode of transport and the design of the conveyors; because slipped, out-of-shape sheet stacks can not be fed to further processing or packaging.

That is why in the DE 35 085 14 A1 proposed to electrostatically charge paper stacks so that they are temporarily fixed in shape for further processing. In this way, it is possible to prevent the stacks from slipping or even flying away the individual sheets, especially when accelerating in a conveyor device.

The DE 101 28 653 A1 teaches the use of an ionization device by means of the sheet layers are electrostatically charged in a conveyor. In this known conveying device, a suction device is arranged in the region of a front conveying device by means of which the sheet layers can be acted upon with suction air in at least one region of the sheet layers.

The DE 101 44 287 A1 discloses a device for the electrostatic fixing of sheet-like objects on a substrate with an electrostatic charging device, designed as a double roller assembly conveyor and a cutting or stamping station. In this known device, the electrostatic charging device is located upstream of the conveyor and the cutting or punching station downstream of the conveyor.

From the DE-A-100 43 211 For example, the arrangement of an electrostatic charging device between upstream pairs of pull rolls and a downstream cutting device having a knife cylinder with a cutting knife and a grooved cylinder is known.

The invention now proposes that in a device of the type mentioned, the endlessly circulating conveyor belt arrangement consists only of one or more subbands on which or which the multilayer material web rests, and is thus designed without a belt.

Due to the inventive arrangement of the electrostatic charging device adjacent to the cutting device in the downstream of the cutting device located conveying device the risk of congestion of the multilayer material web is avoided in the cutting device and thereby significantly reduces the risk of damage to the relatively expensive cutting device. For it has been found according to the invention that it is easier to pull off an already cut and then electrostatically charged material web with the aid of the conveying device than to push an already previously electrostatically charged material web through the cutting device.

The downstream of the cutting device located conveying device has an endless circulating conveyor belt assembly, which consists of only one or more sub-bands, on which or those of the multilayer material web cut superimposed sheets. rest. Due to the fact that the sheets are fixed in themselves by the electrostatic charging, upper bands are no longer required in this conveying device. The omission of the upper strip web leads to considerable structural simplifications and thus to considerable savings. Also, adjustments such as adjustment of the tape positions to the formats or adjustment of the friction of the lower belts to the upper belts are not necessary as in the prior art. In addition, the conveyor device is easily accessible from above by eliminating the upper band path, making it easier to eliminate interference. Finally, the risk of damage to the transported sheets is reduced by the unobstructed free transport, which is particularly relevant for coated paper sheets due to their high sensitivity.

From the DE 21 00 980 A1 Although a device for cutting and conveying of paper sheet is known in which a conveyor downstream of a consisting of a rotating knife and a fixed knife cutting device is arranged and also lonisierungseinrichtungen are provided. However, this conveyor is formed not only Unterbändem, but also from upper bands. In addition, the ionization devices are each enclosed by one of the upper and lower bands and are thus in the region or within that conveying device. Moreover, the ionization devices in this prior art have a completely different purpose. Because two of the three lonisierungseinrichtungen provided there are used as a switch to einzusteuem the passing arc either in one of two subsequent conveyor lines. Associated with one of these two subsequent conveyor lines is a third ionization device, which however only ensures that only the trailing edges of those sheets intended for an overlap are charged.

In order to increase the friction for secure transport of the sheets, in a further preferred embodiment, the conveying device may have a suction device, wherein expediently an upper run of the conveyor belt arrangement runs above the suction device. If the suction device has a suction surface, an upper run of the conveyor belt assembly should rest on such a suction surface. To increase the suction at least one sub-band should be perforated.

Preferably, the electrostatic charging device is an ionizing device.

The cutting device should in particular have a cross cutter.

A further embodiment of the invention, in which an electrostatic discharge device for discharging the sheets electrostatically and a stack tray located downstream of the conveyor for forming stacks of stacked sheets, is characterized in that the electrostatic discharge device is arranged in the region of the stack tray , If the multilayer material web is not selectively electrostatically charged by the device described above and / or electrostatic charging devices at other locations of the machine, the relative movements between machine components and the material and / or within the material taking place during the further processing process may depend on the material and the material Environmental conditions lead to electrostatic charges. These electrostatic charges may hinder the further processing in a subsequent device. For the neutralization of the electrostatically charged material, antistatic units installed firmly over the entire working width are known in the area of the conveying device, which try to to discharge the material passing by them. However, the short residence time of the material under these antistatic units during transport does not result in the desired complete discharge. In addition, the material tends to recharge on its way to the stacker tray. Therefore, the invention proposes to arrange the electrostatic discharge device in the region of the stack tray, where the sheets cut from the multilayer material web come to rest and thus a sufficient residence time for a complete discharge of the sheets is present. This completely eliminates the electrostatic adhesion between the sheets, which also allows for error-free alignment and stacking of the sheets.

Preferably, the electrostatic discharge device is disposed in the upstream portion, preferably on the upstream side, of the stack tray.

A further preferred embodiment of the invention is characterized in that the electrostatic discharge device comprises a compressed air device for generating compressed air, a device for electrostatically charging the compressed air with opposite polarity to the sheets and a blowing device for blowing this air against the sheets. Because the formation of an air cushion between the sinking sheets in the stack tray provides in conjunction with mechanical piecing elements for an accurate edge formation of the resulting stack. The formation of such an air cushion is already known. The invention now uses the compressed air required for this purpose in a clever way to the necessary electrostatic discharge of the sheets by the compressed air is charged with respect to the arcs opposite polarity. Thus, by the targeted introduction of blowing air with electrostatic discharge effect both the aforementioned air cushion provided exactly at the place where the effect must necessarily be present, namely in the stack tray, achieved as well as an electrostatic neutralization of the sheets.

Preferably, the blowing device blows the air substantially against the trailing edges of the sheets.

Expediently, the blowing device has a nozzle arrangement.

In a further preferred embodiment of the invention, the electrostatic discharge device is seated in a housing, one portion of which limits the stack tray and preferably forms a stop for the stacks. Thus, the housing can simultaneously take over the function of a stacking stop. In this case, the portion of the housing which delimits the stack tray should have the blowing device. For this purpose, the portion of the housing delimiting the stack tray can be provided with openings for the blowing out of the air. These openings are designed so that they allow an acceleration of the exiting air with an electrostatic discharge effect in the direction of the forming stack. Conveniently, the housing consists of an electrically non-conductive material.

In particular, the electrostatic discharge device is a deionization device.

Finally, in the lower portion of the stack tray suction means may be provided which sucks disturbing air between the stacking sheets with negative pressure effect.

Fig. 1

in schematischer Seitenansicht ausschnittsweise einen eine lonisiervorrichtung aufweisenden Abschnitt einer papierverarbeitenden Maschine mit Anordnung der lonisiervorrichtung hinter einem Querschneider;

Fig. 2

eine Draufsicht auf den Abschnitt einer papierverarbeitenden Maschine von Figur 1 unter Weglassung der Ionisiervorrichtung; und

Fig. 3

schematisch im Querschnitt ausschnittsweise einen eine Entionisiereinrichtung aufweisenden weiteren Abschnitt einer papierverarbeitenden Maschine.

Hereinafter, preferred embodiments of the invention will be explained in more detail with reference to the accompanying drawings. Show it:

Fig. 1

a schematic side view of a section of an ionizing device having portion of a paper-processing machine with arrangement of the ionizing behind a cross cutter;

Fig. 2

a plan view of the section of a paper processing machine of FIG. 1 omitting the ionizer; and

Fig. 3

schematically in cross-section detail a Deionisiereinrichtung having another section of a paper-processing machine.

A first section of a paper processing machine with a cross cutter 2 is fragmentary in FIG. 1 in a schematic side view in two different versions and in FIG. 2 generally shown in plan view. In the exemplary embodiments illustrated, the cross cutter 2 has a first knife roller 4 with a first knife 5 extending over the entire length of the knife roller 4 and a second knife roller 6 with a second knife 7 extending over the entire length of the knife roller 6. The two cutter rollers 4, 6 rotate synchronously in opposite directions to each other in such a way that the two cutter bars 5, 7 meet to cut a running between the two cutter rollers 4, 6 multilayer paper web 10 into individual superimposed sheets 12.

For transporting the multilayer paper web 10 in the direction of the arrow A, a first conveying device is provided upstream of the cross cutter 2, which is not shown in the figures. Furthermore, downstream of the cross cutter 2 downstream of a second conveyor 20 is arranged, the at least one via deflecting rollers 22, 24 endless circumferential lower band 26 which runs with its upper run 26a in the direction of the arrow A. Usually several sub-bands 26 are arranged transversely to the direction of the sheets 12 according to arrow A next to each other.

In the embodiment according to FIG. 1 is downstream of the cross cutter 2 adjacent to this and thus substantially between the cross cutter 2 and the second conveyor 20 an ionizing device 30 is arranged, which charges the multilayer paper material web 10 static. Preferably, the ionizing device 30 consists of a transverse to the paper direction according to arrow A extending ionizing. By the ionizing device 30 it is achieved that the cut by the cross cutter 2, superimposed sheets 12 adhere to each other and can not slip against each other.

Behind the cross cutter 2, the separated sheets 12 are transported on the lower belts 26 of the second conveyor 20, wherein the individual sheets 12 can not open due to the electrostatic charge. To increase the friction between the sheets 12 and the upper run 26a of the lower belts 26, suction boxes 40 are provided, the upper side of which forms a suction surface 42, over which an upper run 26a of the upper belts 26 runs. The suction boxes 40 are connected to a suction pump, not shown. The suction surfaces 42, which carry the upper run 26a of the lower bands 26, are perforated, such as FIG. 2 lets recognize. In order to increase the suction power in the region of the lower bands 26, these are also perforated accordingly, which in FIG. 2 is also shown schematically. By the suction of the suction boxes 40, the superimposed and adhering to each other by the electrostatic charge sheets 12 are pulled against the upper strands 26a of the sub-bands 26, whereby the friction between the sheets 12 and the moving sub-bands 26 and thus the adhesion of the sheets 12 at this is increased. In this way, a secure transport of the sheets 12 is ensured by the sub-belts 26, so that higher transport speeds are possible.

Moreover, it is conceivable, the suction surfaces 42 and optionally the suction boxes 40 in the paper direction according to arrow A not, as in the FIGS. 1 and 2 shown schematically, continuously, but alternatively divided or form multiple times. Further, it is conceivable, the suction boxes 40 for adjustment and maintenance work removably, in particular pivotable downwards, to order. Finally, in particular for a format change, the suction effect of individual selected suction boxes 40 can be switched off or turned on, which is advantageous for maintaining a constant negative pressure.

The advantage of the arrangement described above is, in particular, that in the second conveying device 20, which transports the sheets 12 to a subsequent overlapping station which is not shown in the drawings, the usual upper bands can be dispensed with. Therefore, the second conveyor 20 has no upper bands, whereby the conveyor line formed by the second conveyor 20 is structurally simplified and operatively accessible.

In FIG. 3 schematically another section of the paper-processing machine in the region of a stack tray 50 is shown in cross section in sections, in which the superimposed incoming sheets 12 are stacked to form a stack 14. In contrast to FIG. 1 are in FIG. 3 the superimposed sheets 12 are shown together only schematically as a continuous line.

Paper processing machines that pull web-shaped materials from one or more rolls and process them into format material are designed in the majority of cases to generate a scaly overlapping stream of sheets 12 within the machine. This scale shape is necessary to avoid the high web take-off and transport speed, which, for reasons of productivity of the plant in which in the FIGS. 1 and 2 shown portion is selected to come to the lowest possible speed for the formation of the stack 14.

Unless a targeted electrostatic charge takes place, as previously based on the FIGS. 1 and 2 have been described during the further processing process relative movements between the machine components and the material or within the material, depending on the selected material and the environmental conditions to electrostatic charges. While such static charges initially during transport through the second conveyor 20 ( Fig. 1 and 2 ) are more or less impeding the formation of a clean stack 14 and, in particular, the ensuing further processing in other stations or devices, which can then severely limit the productivity and quality of the further processing.

For this purpose, an all-sided closed housing 60 is provided, which consists of a non-conductive material. The housing 60 has a compressed air connection 62, which is connected to a compressed air source, not shown, and is pumped by the compressed air in the direction of arrow B in the housing 60. With its one side 64, the housing 60 delimits the stack tray 50. This stack tray 50 facing side 64 of the housing 60 forms in the illustrated embodiment, a vertical flat surface to which the stack 14 is engageable. Thus, in the illustrated embodiment, the side 64 of the housing 60 takes over the function of the rear stack stop and at the same time takes over the Anrichtfunktion. Thus, this vertical Page 64 of the housing 60 may also be referred to as a rear-mounted implement.

In the conveying direction, the stack tray 50 is limited by a front end 68, which serves as a stop for the conveyed to the stack tray 50 sheets 12 and consists essentially of a vertically arranged plate body. Accordingly, the stack tray 50 facing side 64 of the housing 60 and the front end 68 are part of a Anrichtmechanismus or form the Anrichtmechanismus.

Further, in the stack tray 50 facing side 64 of the housing 60 a plurality of nozzle-shaped air outlet openings 66 are formed, in such a way that they form over the entire working width at regular intervals perpendicular drilling patterns. These openings 66 are designed such that they achieve an accelerated exit of the compressed air entering through the compressed air connection 62 compressed air in the direction of the forming stack. The resulting air streams emerge essentially in the longitudinal direction of the sheets 14 forming the sheet 12 and are directed to the rear edges 12a. In this way, in the stack tray 50 between the sinking sheets 12 air cushion, which provide in conjunction with the already mentioned, but not shown piecing mechanism for an accurate edge formation of the resulting stack 14. Because for the formation of the stack 14, it is necessary that the sheets 12, which run in a scaly overlapping arrangement against the Frontanrichter 68, both a good relative displacement with each other and the floating on an air cushion when descending onto the surface of the forming stack 14 allows becomes.

For the electrostatic discharge of the sheets 12, a de-ionizing device 70 is arranged in the illustrated embodiment within the housing 60, which preferably consists of an antistatic rod. This deionizer 70 ionizes the through the compressed air connection 62 in the housing 60 entering compressed air with respect to the sheets 12 opposite polarity, so that the emerging from the outlet openings 66 compressed air simultaneously exerts a de-ionizing effect on the sheets 12 of the forming stack 14. Thus, the selective introduction of blowing air with deionizing effect in the forming stack 14 ensures both an electrostatic neutralization of the sheets 12 and the generation of the air cushion described above exactly at the place where these effects must necessarily be present.

It must be ensured under all circumstances that the housing 60 receives no electrically conductive connections. On the side of the air outlet, ie outside the housing 60 in the region of the outlet openings 66, it is essential to ensure that the escaping deionizing air in the region of the outlet opening 66 and in the further course of the blowing direction in no way comes into contact with electrically conductive components Otherwise she would be neutralized immediately.

The stack tray 50 is bounded below by a bottom 52 are piled on the sheets 12 to form the stack 14 and which is mounted by a mechanism, not shown, in the vertical direction according to double arrow C movable. During the formation of the stack 14 while the lowering movement of the bottom 52 must be controlled so that the stack 14 with the respective uppermost sheet 12 and thus its resulting top always at the height of the outlet openings 66 and in particular between the upper and lower outlet openings 66th is to achieve a functional design of the air cushion through the escaping from the outlet openings 66 deionizing compressed air.

How finally Fig. 3 can also be seen, a squeegee 80 is disposed in the lower region of the stack tray 50, the negative pressure effect disturbing air between the leaves 12 of the stack 14 sucks in the illustrated embodiment in the lower region.

Claims (17)

1. Device for processing a multilayer electrostatically chargeable length of fabric, with at least one cutting device (2) for cutting the multilayer length of fabric (10) into corresponding sheets (12) lying one above the other, a conveying device (20) which is placed downstream behind the cutting device (2) and has an endlessly circulating conveyor belt arrangement (26) to transport the multilayer length of fabric (10, 12), and an electrostatic charging device (30), which is arranged in the region of the conveying device (20), next to the cutting device (2), to charge the multilayer length of fabric (10) electrostatically,
   characterized in that the endlessly circulating conveyor belt arrangement consists only of one or more bottom belts (26), on which the multilayer length of fabric (12) lies, and is thus implemented without a top belt.
2. Device according to Claim 1,
   characterized in that the conveying device (20) has a suction device (40).
3. Device according to Claim 2,
   characterized in that an upper strand (26a) of the conveyor belt arrangement (26) runs above the suction device (40).
4. Device according to Claim 3,
   characterized in that the suction device (40) has a suction area (42), an upper strand (26a) of the conveyor belt arrangement (26) lying on the suction area (42).
5. Device according to Claim 3 or 4,
   characterized in that at least one bottom belt (26) is perforated.
6. Device according to at least one of the preceding claims,
   characterized in that the electrostatic charging device (30) is an ionising device for ionising the multilayer length of fabric (10).
7. Device according to at least one of the preceding claims,
   characterized in that the cutting device (2) has a cross cutter.
8. Device according to at least one of the preceding claims,
   characterized in that an electrostatic discharging device (70) for discharging the sheets (12) electrostatically, and a stacker (50), which is placed downstream from the conveying device (20), are provided to form stacks (14) of sheets (12) lying one above the other, the electrostatic discharging device (70) being arranged in the region of the stacker (50).
9. Device according to Claim 8,
   characterized in that the electrostatic discharging device (70) is arranged in the upstream section, preferably on the upstream side, of the stacker (50).
10. Device according to Claim 8 or 9,
    characterized in that the electrostatic discharging device has a compressed air device for generating compressed air, a device (70) for charging the compressed air electrostatically with opposite polarity to the sheets (12), and a blowing device (66) for blowing this air against the sheets (12).
11. Device according to Claim 10,
    characterized in that the blowing device blows the air essentially against the trailing edges (12a) of the sheets (12).
12. Device according to Claim 10 or 11,
    characterized in that the blowing device has a jet arrangement (66).
13. Device according to at least one of Claims 8 to 12 and Claim 13,
    characterized in that the electrostatic discharging device (70) sits in a housing (60), one section of which delimits the stacker (50) and preferably forms a limit stop for the stacks (14).
14. Device according to at least one of Claims 8 to 12,
    characterized in that the section (64) of the housing (60) which delimits the stacker (50) has the blowing device (66).
15. Device according to Claims 12 and 14,
    characterized in that the section (64) of the housing (60) which delimits the stacker (50) is provided with openings (66) for blowing out the air.
16. Device according to at least one of Claims 8 to 15,
    characterized in that the electrostatic discharging device (70) is a de-ionising device for de-ionising the sheets.
17. Device according to at least one of Claims 8 to 16,
    characterized by suction means (80) in the lower section of the stacker (50).

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