Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H27/00—Special constructions, e.g. surface features, of feed or guide rollers for webs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2301/00—Handling processes for sheets or webs
  • B65H2301/50—Auxiliary process performed during handling process
  • B65H2301/51—Modifying a characteristic of handled material
  • B65H2301/513—Modifying electric properties
  • B65H2301/5132—Bringing electrostatic charge
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2404/00—Parts for transporting or guiding the handled material
  • B65H2404/10—Rollers
  • B65H2404/14—Roller pairs
  • B65H2404/145—Roller pairs other
  • B65H2404/1451—Pressure

Definitions

• the invention relates to a method and a device for electrostatically charging the two outer sides of at least one material web with charges of opposite polarity, before the further processing of the at least one material web, which is guided through the gap of a pair parallel to one another and at a short distance from one another.
• Such a method and a device for electrostatic charging are known (DE-31 17 419 AI).
• several material webs are brought together to form a strand and only the two outer sides are charged by means of a device designed as a corona charging electrodes for electrostatic charging after the first pair of rollers by means of a high-voltage source of 30 kV.
• a disadvantage of this known device is the spatially not very targeted charging of the two outer sides of the material webs. A large part of the charged particles vagabundate in the entire area where the charging takes place. This results in poor charging efficiency. There is also a risk that in the case of unfavorable Environmental conditions contaminate the corona charging electrodes and consequently fail to function. The cleaning effort can be very considerable.
• the invention has for its object to propose a generic method and a generic device, by means of which a more targeted charging with better efficiency is possible.
• the roller can be charged over the surface by means of a so-called contact roller (DE-38 23 739 AI), via brushes known per se, a sliding contact or a corona charging electrode.
• a so-called contact roller DE-38 23 739 AI
• brushes known per se a sliding contact or a corona charging electrode.
• the charging is carried out from the inside by the device formed by the pair of rollers, each roller having a limited electrically conductive (so-called semiconducting) coating over a steel jacket and - for electrically charging the limited conductive coating -
• the steel jacket of each roller can be connected to a positive or negative high voltage source.
• the device according to the invention because of the supply of the voltage from the inside, it is also possible in particular to retrofit it in existing systems for processing material webs, preferably made of plastic or paper, with a high-voltage source of 3 to 7 kV. Thus, significantly lower voltages are also used with reference to the prior art.
• the axis or shaft of the roller is expediently connected to the steel jacket in an electrically conductive manner and is electrically insulated from the machine frame for the roller.
• the electrical high voltage is applied to the axle or shaft, which has a connection for this purpose. This can either be a fixed connection on the axle or a thrust bearing to be arranged on the end face of the shaft.
• a primary coil with respect to the machine frame is fixed concentrically to the axis or shaft of the roller and concentrically with the axis or shaft of the roller on one end face of which a secondary coil is fixedly attached to this and that one of which is connected to the axle or shaft and the other of which is connected to the steel jacket via a rectifier circuit.
• roller for the purpose of insulation from the machine frame under the highly conductive steel jacket and on both of them End faces has an electrical insulator and the high voltage of the high voltage source is applied via a corona charging electrode for electrically charging the limited conductive coating.
• a corona charging electrode for electrically charging the limited conductive coating.
• FIG. 1 shows a first embodiment of the device according to the invention, in a schematic cross section and a partially broken view
• Figure 2 shows a second embodiment of the device according to the invention, in schematic cross section and partially broken simplified representation
• FIG. 3 shows a third embodiment of the device according to the invention, in a simplified representation partly broken away and broken away;
• Figure 4 shows a fourth embodiment of the device according to the invention, in a partially broken and broken away, simplified representation.
• Each of the two rollers 5 according to FIG. 1 has one 1 in the first embodiment according to FIG. 1 as well as a steel jacket 7, over which a surface with limited conductivity, designated as 8, is arranged, which is electrically chargeable. Between the axis 6 and the steel jacket 7, a ball bearing, generally designated 9, is provided. A gap 50 is present between the two rollers arranged parallel to one another.
• the axis of the roller 5 is mounted in a machine stand, generally designated 10, in an electrical insulation, generally designated 11.
• the distances 12 and 13 are sufficient to prevent discharges or voltage flashovers.
• the end face 16 of the axis 6 is connected to a generator denoted overall by 15 and a measuring device 16 having a connection 17, the line leading to the connection 17 being grounded via a resistor 18.
• the machine stand 10 is also grounded, as indicated schematically at 19.
• FIG. 2 differs from that according to FIG. 1, as only one of the two rollers is shown and the axis 6 there is now designed as a shaft 20 which is rigidly connected to the steel jacket 7 via an electrically conductive intermediate piece 21.
• the shaft 20 of the machine stand 10 is connected either via an electrically insulating ball bearing 22 or a separate insulation 11. It is also possible to use a normal, electrically conductive ball bearing and to provide an electrically insulating sleeve 11 between it and the machine stand 10. Furthermore, on the end face 14 of the shaft 20, a pressure bearing, designated overall by 23, is provided as a connection, which is electrically conductive and on the outside of which the connection 17 of the high-voltage generator 15 is attached via the measuring device 16.
• Machine room 10 can get because of the electrical insulation 11, on the other hand, the high voltage can reach the limited conductive coating 8 of the roller 5 from the inside.
• the further, third embodiment according to FIG. 3 also has two rollers with the formation of a gap, of which, however, for reasons of better clarity, only one roller as shown in FIGS. 1 and 2 is shown. Furthermore, concentric to the shaft 6 of the roller 5, in addition to the latter on the one end face 112, there is a first receiving device, generally designated 113, as a magnetizable core with a secondary coil 114 and a second secondary coil 115, each concentric to the shaft 6.
• a further receiving device 116 is arranged concentrically with the shaft 6 as a magnetizable core for receiving a primary coil 117 with electrical connections 1 and 2, which is also concentric with the shaft 6, and a second primary coil 18 with electrical connections 3 and 4 arranged between the latter and the shaft 6.
• the receiving device 16 can be rotated with respect to the shaft 6 by means of a pin 19 which engages in an anchorage 120 which is fixed with respect to the machine frame and has an overall joint on its inside 121 designated ball bearing so that it can rotate, but the magnetizable core due to the pin 119 and the anchor 120 with respect to the first receiving device 113 can be held against rotation.
• a rectifier circuit 122 and a smoothing circuit 123 are also provided on the secondary side of the first receiving device 113, and their output is connected to the limited conductive coating 8.
• the electrical connection 2 of the primary coil 117 is grounded, whereas the electrical connection 1 can be connected to an AC voltage generator.
• the two electrical connections 3 and 4 of the second primary coil 118 can be connected to the inputs of a control circuit which can change the size of the output voltage and / or its frequency - in a manner known per se.
• the secondary coil 114 is grounded on one side. The same also applies to the second secondary coil 115. Both secondary coils 114, 115 are connected in parallel.
• the rectifier circuit 122 for rectifying the alternating current is initially arranged downstream of both coils. After the rectifier circuit 122 is the smoothing circuit 123, e.g. arranged in the form of an LC filter, as known per se. The output of the smoothing circuit 123 is connected to the limited conductive coating 8 of the roller 5.
• the secondary coil 114 is moved relative to the primary coil 117. Via the air gap between the two magnetizable cores of the receiving device 113 and 116, the alternating voltage of the primary coil 117 can induce a secondary voltage in the secondary coil 114 which is rectified via the rectifier circuit 122 and the smoothing circuit 123 to the limitedly conductive "covering 8 is fed smoothed directly.
• the induced voltage of the secondary coil 114 is taken by the second secondary coil 115 and induced in the second primary coil 118 in the reverse sense, with their electrical connections 3 and 4 to a control circuit can be connected, which can control the AC voltage source in such a way that the same direct voltage is always applied to the limited conductive coating 8 of the roller 5.
• the embodiment according to FIG. 4 differs from the previous versions in that the shaft or axis 6 or 20 of the machine frame 10 is arranged directly through an electrical insulator layer 40 under the steel jacket 7 of the roller 5.
• this electrical insulator extends on the two end faces 41 as an end insulator layer 42 which extends in the radial direction at least up to the layer 40 which is concentric with respect to the axis, shaft 6 or 20. However, it can also extend to the outer edge.
• a high-voltage source 43 is provided, the output of which is connected to a corona charging electrode, denoted overall by 44, which extends in the axial direction over a short axial region, essentially parallel to the shaft or axis 6, 20, and the limited conductive coating 8 is opposite.
• a charge is created which is distributed evenly over the entire surface due to the highly conductive steel jacket 7 arranged beneath it, so that the limited conductive coating 8 can serve to charge the material web.
• the roller can also be designed as an impression roller in a gravure printing unit in order to do so to form the electrostatic pressure support.

Landscapes

• Elimination Of Static Electricity (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Electrostatic Charge, Transfer And Separation In Electrography (AREA)
• Treatment Of Fiber Materials (AREA)
• Current-Collector Devices For Electrically Propelled Vehicles (AREA)
• Charge And Discharge Circuits For Batteries Or The Like (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=7825271

Family Applications (2)

Family Applications Before (1)

Country Status (9)

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Family Cites Families (21)

• 1997
  • 1997-04-02 DE DE19713662A patent/DE19713662A1/de not_active Withdrawn
  • 1997-04-02 DE DE29723999U patent/DE29723999U1/de not_active Expired - Lifetime
  • 1997-11-16 DE DE59707978T patent/DE59707978D1/de not_active Expired - Lifetime
  • 1997-11-16 AT AT97950196T patent/ATE222210T1/de active
  • 1997-11-16 AU AU53224/98A patent/AU736011B2/en not_active Ceased
  • 1997-11-16 ES ES97950196T patent/ES2181044T3/es not_active Expired - Lifetime
  • 1997-11-16 EP EP97950196A patent/EP0923500B1/fr not_active Expired - Lifetime
  • 1997-11-16 US US09/142,828 patent/US6159555A/en not_active Expired - Lifetime
  • 1997-11-16 WO PCT/EP1997/006387 patent/WO1998043904A1/fr active IP Right Grant
  • 1997-11-16 JP JP53808798A patent/JP3258034B2/ja not_active Expired - Fee Related
• 1998
  • 1998-03-31 US US09/402,253 patent/US6445562B1/en not_active Expired - Fee Related
  • 1998-03-31 WO PCT/EP1998/001855 patent/WO1998043905A1/fr not_active Application Discontinuation
  • 1998-03-31 ES ES98917100T patent/ES2169509T3/es not_active Expired - Lifetime
  • 1998-03-31 EP EP98917100A patent/EP0971851B1/fr not_active Revoked
  • 1998-03-31 DK DK98917100T patent/DK0971851T3/da active
  • 1998-03-31 JP JP54115398A patent/JP3284503B2/ja not_active Expired - Fee Related
  • 1998-03-31 AU AU70425/98A patent/AU7042598A/en not_active Abandoned
  • 1998-03-31 AT AT98917100T patent/ATE210593T1/de not_active IP Right Cessation
  • 1998-03-31 DE DE59802440T patent/DE59802440D1/de not_active Revoked

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