EP0114329B1 - Printing device with additional electrostatic field - Google Patents

Printing device with additional electrostatic field Download PDF

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Publication number
EP0114329B1
EP0114329B1 EP83112742A EP83112742A EP0114329B1 EP 0114329 B1 EP0114329 B1 EP 0114329B1 EP 83112742 A EP83112742 A EP 83112742A EP 83112742 A EP83112742 A EP 83112742A EP 0114329 B1 EP0114329 B1 EP 0114329B1
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EP
European Patent Office
Prior art keywords
inductor
impression roller
tube
printing device
outer sheathing
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP83112742A
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German (de)
French (fr)
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EP0114329A1 (en
Inventor
Walter Spengler
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Individual
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Individual
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Publication date
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Priority to AT83112742T priority Critical patent/ATE25035T1/en
Publication of EP0114329A1 publication Critical patent/EP0114329A1/en
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Publication of EP0114329B1 publication Critical patent/EP0114329B1/en
Expired legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F9/00—Rotary intaglio printing presses
    • B41F9/001—Heliostatic printing

Definitions

  • the invention relates to a printing unit, in particular a gravure printing device, with an electrostatic printing aid for supporting the ink transfer from a printing cylinder to a dielectric substrate web according to the preamble of patent claim 1 (GB-A-1 293 302).
  • an inductor device which has an elongated electrode carrier in which one or more rows of inductor electrodes are cast. These electrodes have tips protruding from the electrode carrier, which are aligned approximately parallel to the outer jacket layer along the impression roller and, when high voltage is applied, apply an electrostatic charge from the outside to the outer jacket layer consisting of a semiconductor material without contact and distribute it evenly over a desired layer width.
  • the charge-bearing layer section acts on the substrate web to be printed in such a way that the ink is applied to the substrate web from the engraving cups of the adjacent printing cylinder, even with a low contact pressure of the impression roller, in a much more uniform and high-contrast manner than with printing units without work with an electrostatic printing aid.
  • the use of the electrostatic printing aid has proven to be very useful, especially for low-quality papers that are considered difficult to print. It can be used to achieve impressive print results even when using inexpensive paper qualities. Noticeable energy savings can also be achieved when printing with an electrostatic printing aid, since a considerably lower pressure can be set for the ink transfer from the printing cylinder to the substrate web than without a printing aid; this also reduces wear on the printing unit. Press rollers that can be used in such printing devices are described, for example, in DE-A-28 10452.
  • the electrode carrier of the inductor device with longitudinally displaceable cover members, which act as an electrically insulating shield to protect the person with the electrostatic charge to make the circumferential section of the impression roller to be provided adjustable depending on the width of the substrate web to be printed.
  • the end faces of the impression roller with an insulating cover which prevents the charge from flowing laterally from the outer surface layer of the impression roller to the grounded roller bearing (CH-A-607624).
  • a proposal described in GB-A-1 293302 provides for conductor bars oriented along the impression roller to be inserted into the electrically insulating outer jacket layer.
  • the conductor bars which can be fed either from the inside of the roller via an outer brush arrangement or via an axial feed line, optionally extend over all or part of the length of the outer jacket layer. This makes it possible to preselect the desired position or the width of the electrostatically charged area of the impression roller surface.
  • the disadvantage here is that special leads must be provided for each group of conductor bars assigned to a specific width range, each of which must be insulated from one another and from ground for the operational high voltage.
  • the object of the invention is now to provide a printing unit of the type defined in the introduction, in which any impairment of the inductor device by the ink and solvent mist occurring during printing and the dust from the substrate web is excluded.
  • the inductor device is provided in the interior of the hollow cylindrical impression roller and is thus protected from any risk of contamination during the printing process.
  • the arrangement according to the invention of the inductor device in the interior of the impression roller it can be operated in an environment which is completely free of contaminants. This can also simplify the monitoring of the printing process itself.
  • the arrangement of the inductor device inside the impression roller furthermore offers advantageous protection against contact and low maintenance costs. For the Feeding the high voltage through one of the end bearing arrangements does not require any costly changes to the bearing, since only one feed hole has to be provided for the insertion of the central shaft region of the bearing journal which is otherwise not used.
  • a printing unit 1 includes a printing cylinder 2, which is immersed in an ink bath contained in an ink fountain 40.
  • the printing cylinder 2 When the printing cylinder 2 is rotated, it takes printing ink from the ink bath on its surface, which is wiped off by a doctor blade 41, so that only printing ink remains in the engraving cups on the surface of the printing cylinder.
  • the pressure cylinder 2 is rotated in the direction of arrow I by a drive (not shown) via a shaft 42.
  • a hollow cylindrical impression roller 4 which is shown in more detail in FIG. 2, is arranged above the impression cylinder 2 in FIG. 1.
  • the impression roller 4 is driven in the direction of arrow II, opposite to the direction of rotation of the impression cylinder 2.
  • a printing nip 6 is formed between the impression roller 4 and the printing cylinder 2, through which a substrate web 3 to be printed is passed.
  • the hollow cylindrical impression roller 4 shown in the figures has a multi-layer hollow cylinder wall structure 12.
  • a hollow cylinder 44 made of metal forms the supporting core of the impression roller 4.
  • the mentioned bearing journals 43 are fitted, on which the The impression roller is rotatably guided and supported in its bearing arrangements 10.
  • the hollow cylinder 44 On its outer surface, the hollow cylinder 44 has a jacket 48 made of an electrical insulating material with a high dielectric constant.
  • an electrostatically chargeable outer jacket layer 5 is applied, which consists of a semiconductor material. When the impression roller 4 is used, this outer jacket layer 5 comes into direct contact with the substrate web surface facing it in the manner shown in FIG. 1.
  • this outer cladding layer it is therefore expedient for this outer cladding layer to choose a highly abrasion-resistant material with semiconductor properties which has sufficient elasticity to meet the pressure requirements in the pressure gap 6.
  • a polyurethane can be used for the outer jacket layer, which is also referred to as “cover” in impression rollers.
  • the wall structure 12 also includes additional layers or segments, the structure and function of which will be described in detail. It goes without saying that all layers, layers or segments of the hollow cylinder wall structure are firmly connected to one another, so that detachment of the layers during operation is impossible in any case.
  • an inductor device 7 is provided in the interior 8 of the hollow cylindrical impression roller 4.
  • this inductor device 7 each has an inductor ring member 14, to which an inductor ring 19, which is mounted on a tube 18 guided concentrically in the interior 8, is assigned.
  • Each of the three inductor ring members 14 visible in FIG. 2 has an annular electrode carrier 15, preferably made of a casting resin, which is enclosed by two annular side boundaries 37 (cf. FIG. 3). Approximately midway between the side boundaries 37, a plurality of electrodes 16 lie one behind the other in a row in the circumferential direction of the impression roller 4 and in about the same distances over the circumference of the ring member 14 (see FIG. 1) embedded.
  • Electrodes 16 are insulated from the hollow cylinder 44 from metal with high voltage resistance by the casting resin and each carry an electrode tip 17 on the inner circumferential area of the annular electrode carrier 15. All electrode tips 17 of the electrodes 16 embedded in an electrode carrier 15 end at one concentric with the axis of rotation R of the impression roller 4 Imaginary circle K.
  • a conductor 13 is connected to each electrode 16, which is passed through a radial bore 38 that breaks through the hollow cylinder 44 in an insulated manner and is fastened to a layer underside 21 of the electrostatically chargeable outer jacket layer 5 via a contact point 20.
  • the line means 13 which can be designed as a thin wire, an electrical coupling element 49, z. B.
  • the electrode 16 can be designed as a simple connection and guide sleeve for the electrode tip 17, but also as a high-voltage switching element which can be operated by remote control in various known ways. With a design as a switching element, it would be possible, depending on the desired conditions of use, to switch off a few electrodes from a row in series from their associated line means 13.
  • the annular electrode carrier 15 is placed with its outer circumferential surface directly on the wall inner surface 11 of the hollow cylinder 44, which encloses the interior 8 of the impression roller 4, and is fastened there. It would also be possible, as indicated in FIG. 2, to coat the hollow cylinder 44 made of metal on its surface facing the interior 8 with an inner insulation material layer 50 and to apply the electrode carrier (s) 15 thereon.
  • the tube 18 extends concentrically through the impression roller 4 and is guided at its two end portions in the journal 43 of the bearing arrangement 10, so that it is rotatable relative to the impression roller 4 and axially displaceable.
  • the tube 18 carries a plurality of inductor rings 19, each of which is connected to a high-voltage feed 9, which is introduced through the interior of the tube 18 from outside the impression roller 4.
  • the tube 18 can be made of insulating material, and the inductor rings 19 can be made of a metallic material that can be cadmium-coated for reasons of corrosion resistance and resistance to electrolytic removal.
  • the inductor rings 19 are connected to the high-voltage feed 9, and certain adjacent inductor rings can be moved in and out again by axially displacing the tube 18 into the circles of certain inductor ring members 14 formed by the electrode tips 17. If the axial distribution of the inductor rings 19 takes place on the shaft 18, as indicated in FIG. 2, and all the inductor rings 19 are connected to the high-voltage supply 9, there is an inductor ring 19 in each of the three inductor ring members 14 within the circle K such that their outer ring surfaces take the shortest possible distance from the respective electrode tips 17. In this position, as shown in FIG.
  • the further inductor rings 19, which are also under high voltage, are located somewhat outside the area of the relevant inductor ring member 14 which is delimited by the annular side boundaries 37.
  • the annular side boundaries 37 can advantageously be drawn radially inwards towards the tube 18 at least up to the circle K occupied by the electrode tips, as a result of which the electrode tips 17 of an inductor ring member 14 are shielded from voltage induction from adjacent inductor rings.
  • the inductor rings 19 on the tube 18 shown in FIG. 2 were to be shifted towards the right side of the drawing until the next inductor ring on the tube is again within the circles K formed by the electrode tips 17, there would only be two, namely 2, the inductor rings 19 are located in the right inductor ring members 14, while the electrode tips 17 in the left inductor ring member 14 only face the insulated surface of the tube 18. In this position, the high voltage can be induced via the high voltage supply 9 only on the two inductor ring members 14 on the right in FIG. 2. If one were to make a further axial displacement in the same direction, ie to the right in FIG.
  • the leftmost inductor ring 19 in the drawing would be opposite the electrode tips 17 of the left inductor ring member 14 during the two right inductor ring members would face the insulated surface of tube 18.
  • the described selection of the axial positions of the respective inductor rings 19 relative to the inductor ring members 14 makes it clear which combination principle allows the further switching variants between the three inductor ring members shown and also between a larger number of inductor ring members, for example in the case of long impression rollers. It would also be possible to provide circuit means on the tube 18 or within the tube, which the or some inductor rings 19 from the high Switch off the voltage depending on the desired operating conditions.
  • an end section 25 of the tube 18, advantageously at the end receiving the high-voltage supply 9, projects axially out of one of the bearing arrangements 10 and is provided with markings 27 make the respectively set position of the inductor rings 19 visible at a fixed mark 28 (FIG. 2). This enables the desired switching on or off of a specific inductor ring member 14 in the interior 8 of the impression roller 4 in an extremely simple manner.
  • the storage or guidance of the tube 18 in the bearing pin 43 of the impression roller 4 can be designed such that both axial ends of the tube 18 are open to the outside of the impression roller. It is preferred, however, that only the high-voltage supply side of the bearing pin 43 on the right in FIG. 2 has a guide which completely penetrates the pin, while the left end of the bearing pin 43 in FIG. 2 is sealed off from the interior 8 of the impression roller 4.
  • an explosion-proof sealing packing 26 is attached between the bearing arrangement 10 and the end section 25 of the tube 18 protruding therefrom for the pressure-tight sealing of the interior 8 of the impression roller 4.
  • Such a sealing packing must be able to withstand an overpressure to be built up in the interior 8 according to the applicable explosion protection regulations or to be able to seal an inert gas atmosphere which may be present in the interior. So that when maintenance becomes necessary on the impression roller or inductor device 7, the tube 18 equipped with the inductor rings 19 can easily be pulled out of the interior 8 of the impression roller 4, it is also advantageous if the largest diameter on the equipped tube is smaller than the clear width of the axial pipe guide in the bearing pin 43.
  • the already described hollow cylinder wall structure 12 with its at least two outer shells, the insulation sheath 48 and the outer sheath layer 5 made of semiconductor material, can be modified for different uses of the impression roller 4.
  • a two-layer wall structure 12 is shown in FIG. 4.
  • the line means 13 guided through the radial bores 38 are each directly connected to the underside 21 of the outer jacket layer 5 via contact points 20.
  • These contact points 20 can be arranged one behind the other in the circumferential direction of the impression roller, without having a direct conductive connection to one another, or can be connected by a ring conductor 22 shown in FIG. 1. If an inductor ring member 14 shown in FIGS. 1 to 3 is induced in a hollow body wall structure 12 according to FIG.
  • a row of contact points 20 lying one behind the other in the direction of rotation of the impression roller thus enables an annular charge zone to be formed on the outer jacket layer 5, which is indicated by one of the ring segment-shaped peripheral surface sections 36 in FIG. 4.
  • the area of the impression roller lying outside such a surface section remains essentially free of electrostatic charge. If one would like (in a two-layer structure) to provide several surface areas 36 of the outer jacket layer 5 with electrostatic charge at the same time, several segments can be provided in the axial direction, for example as shown in FIG.
  • Another possibility for electrostatic charge distribution on certain circumferential surface sections of the impression roller consists, in addition to the application of transverse lines, as mentioned, in the ring-shaped arrangement of conductors 22 shown on FIG. 1 on the underside 21 of the outer jacket layer 5.
  • Such conductors 22, like the aforementioned one Transverse conductors can be made of wire, conductor layers, conductor tracks, conductive coatings and the like.
  • the hollow cylinder wall structure 12 comprises three outer layers, that is to say that a conductor layer 24, as shown in FIG. 3, is applied to the jacket 48 made of electrical insulating material and covering the metal hollow cylinder 44, and the outer jacket layer 5 made of semiconductor material is in turn applied thereon. All contact points 20 of the line means 13 could be connected to this conductor layer 24. This would transfer the charge uniformly to the entire outer jacket layer.
  • the conductor layer 24 can be divided into three conductor strips 23, as shown in FIG. 2. Each of these conductor strips 23 is connected to the electrodes 16 or the line means 13 of one of the three inductor ring members 14, which are located in the interior 8 of the impression roller 4.
  • all three conductor strips 23 can release their charge to the outer jacket layer when high voltage is applied to all inductor ring members 14. So that a uniform charge distribution takes place over the entire width on the one hand when operating all the inductor ring members 14 provided and on the other hand when inducing high voltage on one or more but not all inductor ring members it is ensured that only the conductor strips 23 supplied with voltage in each case have the desired peripheral surface section of the outer jacket layer 5 charge, a distance A must be provided between adjacent edges of the conductor strips 23 such that an optimal compromise can be made between all possible operating modes, taking into account relevant material and voltage values.
  • the conductor strips 23 in the three-layer hollow cylinder wall structure 12 according to FIG. 2 are subdivided in the axial direction of the impression roller 4, so that, as shown in the lower part of FIG. 1, a row of circumferential sectors 58 lying one behind the other in the running direction of the roller is formed .
  • the distance between adjacent circumferential sectors 58 can correspond to the distance A between conductor strips 23 in FIG. 2.
  • This hollow cylinder wall structure is particularly suitable for electrostatic charging of a mainly transverse field on the outer jacket layer 5, i. H. a field extending over one or more axially adjacent rows or rows of circumferential sectors 58, while the remaining circumference of the impression roller 4 can remain essentially free of charge.
  • FIG. 3b shows a schematic view of the variant according to FIG. 3a seen in the direction of the arrow 3b drawn there.
  • the inductor ring 19 explained with reference to FIG. 3 consists of at least one inductor ring segment 51 which, as shown in FIG. 3b, is only provided on part of the circumference of the tube 18.
  • the remaining peripheral region of the inductor ring 19 consists of insulating material, preferably that of the tube 18.
  • the inductor ring segment 51 has a width in the axial direction of the tube 18 which corresponds approximately to the width of the inductor ring 19 according to FIG.
  • each inductor ring segment 51 is connected to the high-voltage feed 9.
  • the ring segments 51 are also axially displaceable by means of the tube 18 and their relative position, as described with reference to the embodiment according to FIG. 3, is displayed outside the impression roller 4. If there are several inductor ring segments 51 on the tube 18, they are arranged in alignment with one another in the axial direction of the tube.
  • the ring segments 51 on the tube 18 mainly electrostatically charge the section of the outer jacket layer 5 of the impression roller 4 that is located in the vicinity of the pressure gap 6, the ring segments 51 are aligned with those electrodes 16 or their electrode tips 17 that are located in the vicinity of the pressure gap 6 are located or move into it.
  • the ring segments 51 which are aligned in a row on the tube 18 could be arranged at the point X in FIG.
  • the tube 18 carrying the ring segments 51 can be rotated relative to the impression roller.
  • the end portion 25 of the tube 18 which, as in FIG. 2 shown, axially led out on one of the bearing arrangements 10, is also suitable for a targeted rotation of the tube 18 and thus for adjusting the angle of rotation of the ring segments 51, for. B. in relation to the center of the pressure gap 6.
  • a graduation is applied to the protruding end section 25 of the tube 18, as shown in FIG. 2, which reproduces the respective rotary position of the ring segments 51 via a fixed rotary position marker 53.
  • the embodiment of a hollow cylindrical impression roller 4 with electrostatic pressure aid shown in FIG. 4 has, as mentioned, a two-layer outer jacket on the hollow cylinder 44.
  • the jacket 48 made of electrical insulating material is led down over the end faces of the bearing pin 43 in order to drain off at the edge to exclude the charge from the electrostatically chargeable outer jacket layer 5 to the grounded mounting arrangement 10.
  • the particular design and the extent to which the insulating jacket 48 is pulled down over the end faces of the impression roller depends on the operational high voltage values and the materials selected.
  • the hollow cylinder 44 is provided with an inner surface insulation 50 corresponding to the jacket 48, so that the wall surface 11 surrounding the interior 8 is formed from the inside of the insulation 50.
  • the inductor device 7 is formed by an inductor disk member 31 which has a circular electrode carrier 32, in which a plurality of electrodes 33 are embedded, insulated in a circumferential direction and insulated from high voltage.
  • the electrode tips 17 oriented towards the axis of rotation R of the impression roller 4 in the embodiment according to FIGS. 1 to 3 are arranged toward the outside of the axis of rotation R towards the inside wall 11 in the embodiment according to FIG. 4 and form the electrode tips 34.
  • These electrode tips 34 lie on an imaginary circle K 'concentric with the inner wall surface 11.
  • the inductor disc member 31 is non-rotatably seated on a hollow shaft 30 which, similar to the tube 18, is made of insulating material.
  • the high-voltage feed 9 is passed through the hollow shaft 30 to the electrodes 33.
  • electrical coupling elements 49 are electrical coupling elements 49.
  • a row of contact elements 35 is attached all the way around in the direction of rotation of the impression roller 4, which contact elements 13 lead into the outer jacket layer 5 through the radial holes 38 in the jacket 48 Connect.
  • These contact elements 35 can be attached as closed rings, which are made of a similar material to the inductor rings 19, concentrically along the inner surface insulation 50 and can connect several or all of the line means 13, which lie in a radial plane, to one another. As indicated in FIG.
  • the two-layer wall structure 12 of the impression roller 4 according to FIG. 4 is advantageously suitable for the construction of electrostatic charge zones in the vicinity of the respective contact points 20 on the underside 21 of the outer jacket layer 5, which, depending on the type of semiconductor material used and the induced voltage, have more or less large charge zones can provide.
  • the charge distribution in these zones decreases, starting from the respective contact point, so that practically sections of low to very small charge are formed between adjacent charge zones.
  • These zones represent a kind of charge grid structure in the running and axial directions of the impression roller.
  • a plurality of electrodes 33 of an inductor disk member 31 are provided in a segment 54 of the disk member.
  • This segment which can also be designed so that the part of the inductor disc member which is not equipped with the electrodes is omitted, is in the interior 8 of the hollow cylindrical impression roller 4 to those cones Aligned clock elements 35, which each transfer the charge to the section of the outer jacket layer 5 located in the vicinity of the pressure gap 6.
  • all segments 54 are arranged in alignment with one another in the axial direction of the shaft.
  • the simultaneous induction in the axial direction via the electrodes 33 results in a corresponding charge distribution on the outer cladding layer 5.
  • the high-voltage-supplying section formed by the respective disk link segment 54 preferably comprises a segment angle ⁇ of approximately 90 ° to 120 °.
  • the high voltage 9 is supplied, as in the embodiment according to FIG. 4, through the hollow shaft 30.
  • the hollow shaft 30 is off on it of the bearing arrangement 10 projecting section 55 with a graduation 56 (FIG. 4), which makes the respective position of the segment 54 visible at a suitable fixed rotational position marking 57.
  • This adjustability of the segments 54 allows a change in the width of the cargo area on the outer jacket in the running direction, with respect to the printing nip, even when the printing unit is running, thereby reducing the printing quality. can be made or corrected.
  • the outer jacket layer changes in accordance with the diameter of the impression roller, the optimum number of radial bores must also be determined for each diameter. At least four and a maximum of twelve radial bores 38 distributed over the circumference are provided lying in a radial plane for the impression rollers currently used.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rotary Presses (AREA)
  • Inking, Control Or Cleaning Of Printing Machines (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
  • Printing Methods (AREA)
  • Microscoopes, Condenser (AREA)
  • Paper Feeding For Electrophotography (AREA)
  • Rolls And Other Rotary Bodies (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)

Abstract

1. Printing device with additional electrostatic field for assisting the colour transfer from a printing cylinder (2) onto a dielectric substrate web (3) in a printing gap (6) formed between he printing cylinder surface and an electrostatically chargeable outer sheating layer (5) of a hollow-cylindrical impression roller (4), with the outer sheathing layer (5), for the electrostatic charging of at least one section of the outer sheathing layer (5) of the impression roller (4), which selection is in each case moved through the printing gap, being loaded with a high voltage which is fed into the inner space (8) of the impression roller (4) via a highvoltage lead (9) guided through at least one of the endface bearing arrangements (10) fo the impression roller (4), and with conducting means (13) which are firmly insulated against high voltage and are guided through the hollow-cylindrical wall construction of the impression roller (4) being available between the inner space of the impression roller (4) and its electrostatically chargeable outer sheathing layer (5), which conducting means (13) are connected at least in section to the outer sheathing layer (5), characterized by an inductor device (7) for loading the outer sheathing layer (5), which inductor device (7) is provided in the inner space (8) of the hollow-cylindrical impression roller (4).

Description

Die Erfindung bezieht sich auf ein Druckwerk, insbesondere einer Tiefdruckeinrichtung, mit elektrostatischer Druckhilfe zur Unterstützung des Farbübertrags von einem Druckzylinder auf eine dielektrische Substratbahn nach dem Oberbegriff des Patentanspruchs 1 (GB-A-1 293 302).The invention relates to a printing unit, in particular a gravure printing device, with an electrostatic printing aid for supporting the ink transfer from a printing cylinder to a dielectric substrate web according to the preamble of patent claim 1 (GB-A-1 293 302).

Bei einem bekannten Druckwerk (CH-A-607 6-24) ist eine Induktoreinrichtung vorgesehen, die einen langgestreckten Elektrodenträger aufweist, in dem eine oder mehrere Reihen von Induktorelektroden eingegossen sind. Diese Elektroden besitzen aus dem Elektrodenträger herausragende Spitzen, die etwa parallel zur Aussenmantelschicht längs der Presseurwalze ausgerichtet sind und bei Zufuhr von Hochspannung eine elektrostatische Ladung von außen auf die aus einem Halbleitermaterial bestehende Aussenmantelschicht berührungslos aufbringen und über eine gewünschte Schichtbreite gleichmässig verteilen. Der ladungstragende Schichtabschnitt wirkt bei seinem Durchlauf durch den Druckspalt auf die zu bedruckende Substratbahn in der Weise ein, dass der Farbauftrag auf die Substratbahn aus den Gravurnäpfchen des anliegenden Druckzylinders bereits bei einem niedrigen Anpressdruck der Presseurwalze wesentlich gleichförmiger und kontrastreicher erfolgt als bei Druckwerken, die ohne eine elektrostatische Druckhilfe arbeiten. Vor allem bei Papieren minderer Qualität, die als schwer bedruckbar gelten, hat sich der Einsatz der elektrostatischen Druckhilfe sehr bewährt. Es lassen sich damit ansehnliche Druckergebnisse selbst bei Verwendung kostengünstiger Papierqualitäten erzielen. Auch kann eine merkliche Energieeinsparung beim Drucken mit elektrostatischer Druckhilfe erreicht werden, da für den Farbübertrag vom Druckzylinder auf die Substratbahn eine wesentlich niedrigere Anpressung eingestellt werden kann als ohne Druckhilfe ; dadurch verringert sich auch der Verschleiss des Druckwerks. Bei solchen Druckeinrichtungen verwendbare Presseurwalzen sind beispielsweise in der DE-A-28 10452 beschrieben.In a known printing unit (CH-A-607 6-24) an inductor device is provided which has an elongated electrode carrier in which one or more rows of inductor electrodes are cast. These electrodes have tips protruding from the electrode carrier, which are aligned approximately parallel to the outer jacket layer along the impression roller and, when high voltage is applied, apply an electrostatic charge from the outside to the outer jacket layer consisting of a semiconductor material without contact and distribute it evenly over a desired layer width. As it passes through the printing nip, the charge-bearing layer section acts on the substrate web to be printed in such a way that the ink is applied to the substrate web from the engraving cups of the adjacent printing cylinder, even with a low contact pressure of the impression roller, in a much more uniform and high-contrast manner than with printing units without work with an electrostatic printing aid. The use of the electrostatic printing aid has proven to be very useful, especially for low-quality papers that are considered difficult to print. It can be used to achieve impressive print results even when using inexpensive paper qualities. Noticeable energy savings can also be achieved when printing with an electrostatic printing aid, since a considerably lower pressure can be set for the ink transfer from the printing cylinder to the substrate web than without a printing aid; this also reduces wear on the printing unit. Press rollers that can be used in such printing devices are described, for example, in DE-A-28 10452.

Um die Ausbreitung der Ladung im Bereich des Druckspalts, insbesondere in seiner Breite, in einem bestimmten Umfang steuern zu können, wurde vorgeschlagen, den Elektrodenträger der Induktoreinrichtung mit längsverschiebbaren Abdeckgliedern zu versehen, welche als ein elektrisch isolierender Schild wirken, um den mit der elektrostatischen Ladung zu versehenden Umfangsabschnitt der Presseurwalze je nach der Breite der zu bedruckenden Substratbahn einstellbar zu gestalten. Ausserdem wurde vorgeschlagen, die Stirnseiten der Presseurwalze mit einer Isolierabdeckung zu versehen, die ein seitliches Abfliessen der Ladung von der Aussenmantelschicht der Presseurwalze zur geerdeten Walzenlagerung verhindert (CH-A-607624).In order to be able to control the spread of the charge in the area of the pressure gap, in particular in its width, to a certain extent, it has been proposed to provide the electrode carrier of the inductor device with longitudinally displaceable cover members, which act as an electrically insulating shield to protect the person with the electrostatic charge to make the circumferential section of the impression roller to be provided adjustable depending on the width of the substrate web to be printed. In addition, it has been proposed to provide the end faces of the impression roller with an insulating cover which prevents the charge from flowing laterally from the outer surface layer of the impression roller to the grounded roller bearing (CH-A-607624).

Diese Massnahmen ergaben ein durchaus zufriedenstellend arbeitendes Druckwerk. Da jedoch während des Betriebs eines Druckwerks ständig Farb- und Lösungsmittelteilchen sowie Staub von der Substratbahn in die Umgebung des Druckwerks gelangen, bilden sich Ablagerungen dieser Verunreinigungen auf der Elektrodenanordnung der Induktoreinrichtung. Zwar lassen sich solche Ablagerungen - wie dies auch bei den Teilen des Druckwerks regelmässig notwendig ist - wieder entfernen. Die Praxis zeigt jedoch, dass sich über einen längeren Einsatzzeitraum der Anlage auf dem gesamten Elektrodenträger, vor allem an schwer zugänglichen Stellen, ein aus Farbe und Verunreinigungen zusammengesetzter Belag ausbildet. Dieser Belag bildet elektrisch leitende Brücken, über welche die Hochspannung von den Elektrodenspitzen auf Masse abfliessen kann. Dabei bilden sich Kriechstrompfade aus, die rasch zur Zerstörung der Induktoreinrichtung führen können. Ausserdem erhöht sich die allgemeine Brandgefahr erheblich.These measures resulted in a printing unit working quite satisfactorily. However, since ink and solvent particles and dust constantly get from the substrate web into the surroundings of the printing unit during the operation of a printing unit, deposits of these contaminants form on the electrode arrangement of the inductor device. Deposits of this type can be removed again, as is regularly necessary for the parts of the printing unit. However, practice shows that over a longer period of use of the system, a coating composed of paint and contaminants forms on the entire electrode carrier, especially in places that are difficult to access. This coating forms electrically conductive bridges over which the high voltage can flow from the electrode tips to ground. This leads to leakage current paths which can quickly destroy the inductor device. In addition, the general fire risk increases considerably.

Es wurden daher Anstrengungen unternommen, die zur Vermeidung solcher Hochspannungsübertritte führen sollten. Ein in der GB-A-1 293302 beschriebener Vorschlag sieht vor, längs der Presseurwalze orientierte Leiterstäbe in die elektrisch isolierende Aussenmantelschicht einzusetzen. Die Leiterstäbe, welche entweder über eine äussere Bürstenanordnung oder über eine axiale Zuleitung von der Walzeninnenseite her anspeisbar sind, erstrecken sich wahlweise über die ganze oder einen Teil der Länge der Aussenmantelschicht. Damit ist es möglich, die gewünschte Lage bzw. die Breite des elektrostatisch aufzuladenden Bereichs der Presseurwalzenoberfläche vorzuwählen. Nachteilig ist dabei, dass für jede einem bestimmten Breitenbereich zugeordnete Gruppe von Leiterstäben besondere Zuleitungen vorzusehen sind, welche jeweils für die betriebsmässige Hochspannung gegenseitig und gegenüber Masse zu isolieren sind.Efforts have therefore been made to avoid such high voltage crossings. A proposal described in GB-A-1 293302 provides for conductor bars oriented along the impression roller to be inserted into the electrically insulating outer jacket layer. The conductor bars, which can be fed either from the inside of the roller via an outer brush arrangement or via an axial feed line, optionally extend over all or part of the length of the outer jacket layer. This makes it possible to preselect the desired position or the width of the electrostatically charged area of the impression roller surface. The disadvantage here is that special leads must be provided for each group of conductor bars assigned to a specific width range, each of which must be insulated from one another and from ground for the operational high voltage.

Die Aufgabe der Erfindung besteht nun darin, ein Druckwerk der eingangs definierten Art zu schaffen, bei dem jegliche Beeinträchtigung der Induktoreinrichtung durch die beim Drucken anfallenden Farb- und Lösungsmittelnebel und den Staub aus der Substratbahn ausgeschlossen ist.The object of the invention is now to provide a printing unit of the type defined in the introduction, in which any impairment of the inductor device by the ink and solvent mist occurring during printing and the dust from the substrate web is excluded.

Die erfindungsgemässe Lösung dieser Aufgabe ergibt sich aus dem Patentanspruch 1. Demgemäss ist die Induktoreinrichtung im Innenraum der hohlzylindrischen Presseurwalze vorgesehen und dadurch vor jeder Verunreinigungsgefahr während des Druckvorgangs geschützt. Durch die erfindungsgemässe Anordnung der Induktoreinrichtung im Innenraum der Presseurwalze kann diese in einer von Verunreinigungen völlig freien Umgebung betrieben werden. Dadurch kann auch die Ueberwachung des Druckvorgangs selbst vereinfacht werden. Die Anordnung der Induktoreinrichtung im Innern der Presseurwalze bietet weiterhin einen vorteilhaften Berührungsschutz und-geringen Unterhaltsaufwand. Für die Zuführung der Hochspannung durch eine der stirnseitigen Lagerungsanordnungen sind keine kostenaufwendigen Aenderungen der Lagerung notwendig, da für das Einführen der ansonsten nicht benutzte zentrale Wellenbereich des Lagerzapfens nur mit einer Zuführungsbohrung zu versehen ist.The solution to this problem according to the invention results from patent claim 1. Accordingly, the inductor device is provided in the interior of the hollow cylindrical impression roller and is thus protected from any risk of contamination during the printing process. As a result of the arrangement according to the invention of the inductor device in the interior of the impression roller, it can be operated in an environment which is completely free of contaminants. This can also simplify the monitoring of the printing process itself. The arrangement of the inductor device inside the impression roller furthermore offers advantageous protection against contact and low maintenance costs. For the Feeding the high voltage through one of the end bearing arrangements does not require any costly changes to the bearing, since only one feed hole has to be provided for the insertion of the central shaft region of the bearing journal which is otherwise not used.

In den abhängigen Ansprüchen sind bevorzugte Ausführungsbeispiele der Erfindung im einzelnen gekennzeichnet. Einige Ausführungsbeispiele werden nachstehend in ihrem vorteilhaften Aufbau und ihren Funktionen anhand der Zeichnung näher erläutert. Es zeigen :

  • Figur 1 eine schematische Seitenansicht eines nach den Merkmalen der Erfindung gestalteten Druckwerks,
  • Figur 2 eine schematische Längsschnittdarstellung einer Ausführungsform einer Presseurwalze für das in Fig. 1 gezeigte Druckwerk,
  • Figur 3 ein vergrößertes Detail einer Induktoreinrichtung in der in Fig. 2 gezeigten Presseurwalze,
  • Figuren 3a und 3b eine abgewandelte Ausführungsform der Induktoreinrichtung nach Fig. 3,
  • Figur 4 eine schematische Längsschnittdarstellung einer abgewandelten Ausführungsform einer mit einer Induktoreinrichtung versehenen Presseurwalze für das in Fig. 1 gezeigte Druckwerk und
  • Figuren 4a und 4b eine Variante der Ausführungsform der Induktoreinrichtung nach Fig. 4.
Preferred embodiments of the invention are characterized in detail in the dependent claims. Some exemplary embodiments are explained in more detail below in terms of their advantageous structure and their functions with reference to the drawing. Show it :
  • FIG. 1 shows a schematic side view of a printing unit designed according to the features of the invention,
  • FIG. 2 shows a schematic longitudinal sectional illustration of an embodiment of an impression roller for the printing unit shown in FIG. 1,
  • FIG. 3 shows an enlarged detail of an inductor device in the impression roller shown in FIG. 2,
  • 3a and 3b show a modified embodiment of the inductor device according to FIG. 3,
  • Figure 4 is a schematic longitudinal sectional view of a modified embodiment of an impression roller provided with an inductor device for the printing unit shown in Fig. 1 and
  • FIGS. 4a and 4b show a variant of the embodiment of the inductor device according to FIG. 4.

Ein Druckwerk 1 umfaßt gemäß Fig. 1 einen Druckzylinder 2, der in ein Farbbad, das in einem Farbkasten 40 enthalten ist, eintaucht. Beim Drehen des Druckzylinders 2 nimmt er an seiner Oberfläche Druckfarbe aus dem Farbbad mit, welche von einer Rakel 41 abgestrichen wird, so daß lediglich noch Druckfarbe in Gravurnäpfchen der Oberfläche des Druckzylinders verbleibt. Über eine Welle 42 wird der Druckzylinder 2 von einem nicht dargestellten Antrieb in Richtung des Pfeils I gedreht.1, a printing unit 1 includes a printing cylinder 2, which is immersed in an ink bath contained in an ink fountain 40. When the printing cylinder 2 is rotated, it takes printing ink from the ink bath on its surface, which is wiped off by a doctor blade 41, so that only printing ink remains in the engraving cups on the surface of the printing cylinder. The pressure cylinder 2 is rotated in the direction of arrow I by a drive (not shown) via a shaft 42.

Oberhalb des Druckzylinders 2 ist in Fig. 1 eine hohlzylindrische Presseurwalze 4 angeordnet, die in Fig. 2 detaillierter gezeigt ist. Eine dort sichtbare stirnseitige Lagerungsanordnung 10, in der die Presseurwalze 4 um einen Lagerzapfen 43 drehbar abgestützt ist, wurde bei der Darstellung in Fig. 1 entfernt, um das Innere der Presseurwalze in axialer Richtung einsehen zu können. Die Presseurwalze 4 wird in Richtung des Pfeils II, entgegengesetzt zur Drehrichtung des Druckzylinders 2 angetrieben. Zwischen der Presseurwalze 4 und dem Druckzylinder 2 wird ein Druckspalt 6 gebildet, durch den eine zu bedruckende Substratbahn 3 hindurchgeleitet wird. Zur Führung dieser Substratbahn, die von einer nicht dargestellten Vorratsrolle in Richtung des Pfeils 111 abgezogen und nach dem Durchlauf durch das Druckwerk 1 in einem weiteren sich anschließenden Druckwerk verarbeitet oder auch aufgespult werden kann, sind in Laufrichtung der Substratbahn zu beiden Seiten des Druckspalts 6 Führungsrollen 45 vorgesehen. In Laufrichtung vor und hinter dem Druckspalt 6 befinden sich zwischen den Führungsrollen 45 lonisatoren 47, welche zur Ableitung von auf der Substratbahn 3 bestehenden elektrostatischen Ladungen dienen.A hollow cylindrical impression roller 4, which is shown in more detail in FIG. 2, is arranged above the impression cylinder 2 in FIG. 1. An end bearing arrangement 10 visible there, in which the impression roller 4 is rotatably supported about a bearing journal 43, was removed in the illustration in FIG. 1 in order to be able to see the interior of the impression roller in the axial direction. The impression roller 4 is driven in the direction of arrow II, opposite to the direction of rotation of the impression cylinder 2. A printing nip 6 is formed between the impression roller 4 and the printing cylinder 2, through which a substrate web 3 to be printed is passed. To guide this substrate web, which is drawn off from a supply roll (not shown) in the direction of arrow 111 and can be processed or wound up after passing through the printing unit 1 in a further subsequent printing unit, there are 6 guide rollers on both sides of the printing nip in the running direction of the substrate web 45 provided. In the running direction in front of and behind the pressure gap 6 there are between the guide rollers 45 ionizers 47, which are used to discharge existing electrostatic charges on the substrate web 3.

Die in den Figuren gezeigte hohlzylindrische Presseurwalze 4 besitzt einen mehrlagigen Hohlzylinder-Wandungsaufbau 12. Bei beiden dargestellten Ausführungsformen bildet ein Hohlzylinder 44 aus Metall den tragenden Kern der Presseurwalze 4. An den stirnseitig offenen Enden des Hohlzylinders sind die erwähnten Lagerzapfen 43 eingepaßt, auf denen die Presseurwalze in ihren Lagerungsanordnungen 10 drehbar geführt und abgestützt ist. An seiner Außenfläche trägt der Hohlzylinder 44 einen Mantel 48 aus einem elektrischen Isoliermaterial mit einer hohen Dielektrizitätskonstante. Auf diesen Isoliermantel 48 ist eine elektrostatisch aufladbare Außenmantelschicht 5 aufgebracht, die aus einem Halbleitermaterial besteht. Diese Außenmantelschicht 5 gelangt bei einem Einsatz der Presseurwalze 4 in der in Fig. 1 dargestellten Weise direkt mit der ihr zugewandten Substratbahnfläche in Berührung. Daher ist es zweckmäßig für diese Außenmantelschicht, ein hochabriebfestes Material mit Halbleiter-Eigenschaften zu wählen, welches eine ausreichende Elastizität besitzt, um den Andruckerfordernissen im Druckspalt 6 zu genügen. Für die Außenmantelschicht, die bei Presseurwalzen auch « Bezug genannt wird, kann ein Polyurethan Verwendung finden.The hollow cylindrical impression roller 4 shown in the figures has a multi-layer hollow cylinder wall structure 12. In both of the illustrated embodiments, a hollow cylinder 44 made of metal forms the supporting core of the impression roller 4. At the ends of the hollow cylinder which are open at the ends, the mentioned bearing journals 43 are fitted, on which the The impression roller is rotatably guided and supported in its bearing arrangements 10. On its outer surface, the hollow cylinder 44 has a jacket 48 made of an electrical insulating material with a high dielectric constant. On this insulating jacket 48, an electrostatically chargeable outer jacket layer 5 is applied, which consists of a semiconductor material. When the impression roller 4 is used, this outer jacket layer 5 comes into direct contact with the substrate web surface facing it in the manner shown in FIG. 1. It is therefore expedient for this outer cladding layer to choose a highly abrasion-resistant material with semiconductor properties which has sufficient elasticity to meet the pressure requirements in the pressure gap 6. A polyurethane can be used for the outer jacket layer, which is also referred to as “cover” in impression rollers.

Der auf dem Hohlzylinder 44 aus Metall aufgebrachte Mantel 48 aus elektrischem Isoliermaterial bildet zusammen mit der elektrostatisch aufladbaren Außenmantelschicht 5 die konstruktiven Mindestvoraussetzungen eines Wandungsaufbaus 12 für eine Verwendung der Presseurwalze zur elektrostatischen Druckhilfe. In den einzelnen Figuren umfaßt der Wandungsaufbau 12 noch zusätzliche Schichten oder Segmente, deren Aufbau und Funktion noch im einzelnen beschrieben wird. Es versteht sich, daß alle Schichten, Lagen oder Segmente des Hohlzylinder-Wandungsaufbaus fest miteinander verbunden sind, so daß ein Ablösen der Schichten während des Betriebs in jedem Fall ausgeschlossen ist.The jacket 48 made of electrical insulating material applied to the hollow cylinder 44 made of metal forms, together with the electrostatically chargeable outer jacket layer 5, the constructive minimum requirements for a wall structure 12 for the use of the impression roller for electrostatic printing aid. In the individual figures, the wall structure 12 also includes additional layers or segments, the structure and function of which will be described in detail. It goes without saying that all layers, layers or segments of the hollow cylinder wall structure are firmly connected to one another, so that detachment of the layers during operation is impossible in any case.

Eine Induktoreinrichtung 7 ist erfindungsgemäß im Innenraum 8 der hohlzylindrischen Presseurwalze 4 vorgesehen. Bei der Ausführungsform gemäß Fig. 2 weist diese Induktoreinrichtung 7 jeweils ein Induktorringglied 14 auf, dem jeweils ein auf einem konzentrisch im Innenraum 8 geführten Rohr 18 aufgebrachter Induktorring 19 zugeordnet ist. Jedes der drei in Fig. 2 sichtbaren Induktorringglieder 14 besitzt einen kreisringförmigen Elektrodenträger 15, vorzugsweise aus einem Gießharz, der von zwei kreisringförmigen Seitenbegrenzungen 37 eingeschlossen ist (vgl. Fig. 3). In etwa mittig zwischen den Seitenbegrenzungen 37 sind mehrere Elektroden 16 in einer Reihe in Umfangsrichtung der Presseurwalze 4 hinfereinanderliegend und in etwa gleich großen Abständen über den Umfang des Ringgliedes 14 verteilt (vgl. Fig. 1) eingebettet. Diese Elektroden 16 sind durch das Gießharz gegenüber dem Hohlzylinder 44 aus Metall hochspannungsfest isoliert und tragen jeweils eine Elektrodenspitze 17 am inneren Umfangsbereich des kreisringförmigen Elektrodenträgers 15. Sämtliche Elektrodenspitzen 17 der in einem Elektrodenträger 15 eingebetteten Elektroden 16 enden an einem zur Rotationsachse R der Presseurwalze 4 konzentrischen imaginären Kreis K. Im Inneren des Elektrodenträgers 15 ist an jede Elektrode 16 ein Leitungsmittel 13 angeschlossen, das durch eine den Hohlzylinder 44 durchbrechende Radialbohrung 38 hochspannungsfest isoliert hindurchgeführt und an einer Schichtunterseite 21 der elektrostatisch aufladbaren Außenmantelschicht 5 über eine Kontaktstelle 20 befestigt ist. In das Leitungsmittel 13, das als dünner Draht ausgeführt sein kann, ist ein elektrisches Koppelelement 49, z. B. ein Widerstand oder ein Kondensator, eingeschaltet. Die Elektrode 16 kann als einfache Anschluß- und Führungshülse für die Elektrodenspitze 17 ausgebildet sein, aber auch als ein Hochspannungs-Schaltelement, das auf unterschiedliche bekannte Weise ferngesteuert betätigt werden kann. Mit einer Ausführung als Schaltelement wäre es möglich, je nach den gewünschten Einsatzbedingungen, einige Elektroden aus einer hintereinanderliegenden Reihe von ihrem zugehörigen Leitungsmittel 13 abzuschalten. Der kreisringförmige Elektrodenträger 15 ist bei der Ausführungsform gemäß Fig. 3 mit seiner äußeren Umfangsfläche direkt auf die den Innenraum 8 der Presseurwalze 4 umschließende Wandungsinnenfläche 11 des Hohlzylinders 44 aus Metall aufgesetzt und dort befestigt. Es wäre auch möglich, wie dies in Fig. 2 angedeutet ist, den Hohlzylinder 44 aus Metall an seiner dem Innenraum 8 zugewandten Fläche mit einer inneren Isolationsmaterialschicht 50 zu überziehen und auf diese den bzw. die Elektrodenträger 15 aufzubringen.According to the invention, an inductor device 7 is provided in the interior 8 of the hollow cylindrical impression roller 4. In the embodiment according to FIG. 2, this inductor device 7 each has an inductor ring member 14, to which an inductor ring 19, which is mounted on a tube 18 guided concentrically in the interior 8, is assigned. Each of the three inductor ring members 14 visible in FIG. 2 has an annular electrode carrier 15, preferably made of a casting resin, which is enclosed by two annular side boundaries 37 (cf. FIG. 3). Approximately midway between the side boundaries 37, a plurality of electrodes 16 lie one behind the other in a row in the circumferential direction of the impression roller 4 and in about the same distances over the circumference of the ring member 14 (see FIG. 1) embedded. These electrodes 16 are insulated from the hollow cylinder 44 from metal with high voltage resistance by the casting resin and each carry an electrode tip 17 on the inner circumferential area of the annular electrode carrier 15. All electrode tips 17 of the electrodes 16 embedded in an electrode carrier 15 end at one concentric with the axis of rotation R of the impression roller 4 Imaginary circle K. In the interior of the electrode carrier 15, a conductor 13 is connected to each electrode 16, which is passed through a radial bore 38 that breaks through the hollow cylinder 44 in an insulated manner and is fastened to a layer underside 21 of the electrostatically chargeable outer jacket layer 5 via a contact point 20. In the line means 13, which can be designed as a thin wire, an electrical coupling element 49, z. B. a resistor or a capacitor turned on. The electrode 16 can be designed as a simple connection and guide sleeve for the electrode tip 17, but also as a high-voltage switching element which can be operated by remote control in various known ways. With a design as a switching element, it would be possible, depending on the desired conditions of use, to switch off a few electrodes from a row in series from their associated line means 13. In the embodiment according to FIG. 3, the annular electrode carrier 15 is placed with its outer circumferential surface directly on the wall inner surface 11 of the hollow cylinder 44, which encloses the interior 8 of the impression roller 4, and is fastened there. It would also be possible, as indicated in FIG. 2, to coat the hollow cylinder 44 made of metal on its surface facing the interior 8 with an inner insulation material layer 50 and to apply the electrode carrier (s) 15 thereon.

Wie in Fig. 2 gezeigt, verläuft das Rohr 18 konzentrisch durch die Presseurwalze 4 hindurch und ist an seinen beiden Endabschnitten in den Lagerzapfen 43 der Lagerungsanordnung 10 geführt, so daß es relativ zur Presseurwalze 4 drehbar und axial verschieblich ist. Wie in Fig. 3 vergrößert dargestellt, trägt das Rohr 18 mehrere Induktorringe 19, die jeweils mit einer Hochspannungszuführung 9, die durch das Innere des Rohrs 18 von außerhalb der Presseurwalze 4 eingeleitet wird, in Verbindung steht. Das Rohr 18 kann aus Isoliermaterial gefertigt sein, und die Induktorringe 19 können aus einem metallischen Werkstoff bestehen, der aus Gründen der Korrosionsfestigkeit und der Widerstandsfähigkeit gegen einen elektrolytischen Abtrag kadmiert sein kann. Die Induktorringe 19 sind mit der Hochspannungszuführung 9 verbunden, und bestimmte nebeneinanderliegende Induktorringe können durch eine Axialverlagerung des Rohrs 18 in die durch die Elektrodenspitzen 17 gebildeten Kreise bestimmter Induktorringglieder 14 hinein- und auch wieder herausverlagert werden. Wenn die Axialverteilung der Induktorringe 19 auf der Welle 18, wie in Fig. 2 angedeutet, erfolgt, und sämtliche Induktorringe 19 mit der Hochspannungszuführung 9 in Verbindung stehen, befindet sich bei allen drei Induktorringgliedern 14 jeweils ein Induktorring 19 derart innerhalb des Kreises K, daß ihre Ringaußenflächen den kürzestmöglichen Abstand zu den jeweiligen Elektrodenspitzen 17 einnehmen. In dieser Stellung liegen die weiteren, ebenfalls unter Hochspannung stehenden Induktorringe 19, wie in Fig. 3 gezeigt, etwas außerhalb des von den kreisringflächigen Seitenbegrenzungen 37 abgegrenzten Bereichs des betreffenden Induktorringgliedes 14. Dadurch besteht bereits aufgrund der größeren Abstände zwischen den außerhalb eines Induktorringgliedes liegenden Induktorringen und den innenliegenden Elektrodenspitzen 17 ein höherer Widerstand bezüglich dieser Spitzen als über den Abstand, den der jeweils im Kreis K befindliche Ring zu den Elektrodenspitzen besitzt. Die kreisringflächigen Seitenbegrenzungen 37 können vorteilhafterweise zumindest bis zu dem von den Elektrodenspitzen eingenommenen Kreis K radial nach innen zum Rohr 18 hin heruntergezogen werden, wodurch die Elektrodenspitzen 17 eines Induktorringgliedes 14 vor einer Spannungsinduktion von benachbarten Induktorringen abgeschirmt werden.As shown in Fig. 2, the tube 18 extends concentrically through the impression roller 4 and is guided at its two end portions in the journal 43 of the bearing arrangement 10, so that it is rotatable relative to the impression roller 4 and axially displaceable. As shown enlarged in FIG. 3, the tube 18 carries a plurality of inductor rings 19, each of which is connected to a high-voltage feed 9, which is introduced through the interior of the tube 18 from outside the impression roller 4. The tube 18 can be made of insulating material, and the inductor rings 19 can be made of a metallic material that can be cadmium-coated for reasons of corrosion resistance and resistance to electrolytic removal. The inductor rings 19 are connected to the high-voltage feed 9, and certain adjacent inductor rings can be moved in and out again by axially displacing the tube 18 into the circles of certain inductor ring members 14 formed by the electrode tips 17. If the axial distribution of the inductor rings 19 takes place on the shaft 18, as indicated in FIG. 2, and all the inductor rings 19 are connected to the high-voltage supply 9, there is an inductor ring 19 in each of the three inductor ring members 14 within the circle K such that their outer ring surfaces take the shortest possible distance from the respective electrode tips 17. In this position, as shown in FIG. 3, the further inductor rings 19, which are also under high voltage, are located somewhat outside the area of the relevant inductor ring member 14 which is delimited by the annular side boundaries 37. As a result, there is already a greater distance between the inductor rings lying outside an inductor ring member and the internal electrode tips 17 have a higher resistance with respect to these tips than over the distance that the ring in the circle K has from the electrode tips. The annular side boundaries 37 can advantageously be drawn radially inwards towards the tube 18 at least up to the circle K occupied by the electrode tips, as a result of which the electrode tips 17 of an inductor ring member 14 are shielded from voltage induction from adjacent inductor rings.

Würde man die in Fig. 2 dargestellte Anordnung der Induktorringe 19 auf dem Rohr 18 zur rechten Zeichnungsseite hin verlagern, bis der auf dem Rohr jeweils nächstfolgende Induktorring sich wieder innerhalb der durch die Elektrodenspitzen 17 gebildeten Kreise K befindet, würden sich nur in zwei, nämlich in den in Fig. 2 rechten Induktorringgliedern 14, Induktorringe 19 befinden, während den Elektrodenspitzen 17 in dem linken Induktorringglied 14 lediglich die isolierte Oberfläche des Rohrs 18 gegenüberstünde. In dieser Stellung kann die Hochspannung über die Hochspannungszuführung 9 nur an den beiden in Fig. 2 rechten Induktorringgliedern 14 induziert werden. Würde man nun aus der vorgenannten Stellung des Rohrs 18 eine weitere Axialverlagerung in derselben Richtung, d. h. nach rechts in Fig. 2 vornehmen, befände sich der in der Zeichnung am weitesten links liegende Induktorring 19 gegenüber den Elektrodenspitzen 17 des linken Induktorringgliedes 14, während den beiden rechten Induktorringgliedern die isolierte Oberfläche des Rohrs 18 gegenüberstünde. Die beschriebene Auswahl der Axialstellungen der jeweiligen Induktorringe 19 relativ zu den Induktorringgliedern 14 macht deutlich, nach welchem Kombinationsprinzip die weiteren Schaltvarianten zwischen den dargestellten drei Induktorringgliedern und auch zwischen einer größeren Anzahl von Induktorringgliedern, beispielsweise bei langen Presseurwalzen, ausgeführt werden können. Auch wäre es möglich, Schaltungsmittel am Rohr 18 oder innerhalb des Rohrs vorzusehen, welche die oder einige Induktorringe 19 von der Hochspannung je nach den gewünschten Betriebsumständen abschalten.If the arrangement of the inductor rings 19 on the tube 18 shown in FIG. 2 were to be shifted towards the right side of the drawing until the next inductor ring on the tube is again within the circles K formed by the electrode tips 17, there would only be two, namely 2, the inductor rings 19 are located in the right inductor ring members 14, while the electrode tips 17 in the left inductor ring member 14 only face the insulated surface of the tube 18. In this position, the high voltage can be induced via the high voltage supply 9 only on the two inductor ring members 14 on the right in FIG. 2. If one were to make a further axial displacement in the same direction, ie to the right in FIG. 2, from the aforementioned position of the tube 18, the leftmost inductor ring 19 in the drawing would be opposite the electrode tips 17 of the left inductor ring member 14 during the two right inductor ring members would face the insulated surface of tube 18. The described selection of the axial positions of the respective inductor rings 19 relative to the inductor ring members 14 makes it clear which combination principle allows the further switching variants between the three inductor ring members shown and also between a larger number of inductor ring members, for example in the case of long impression rollers. It would also be possible to provide circuit means on the tube 18 or within the tube, which the or some inductor rings 19 from the high Switch off the voltage depending on the desired operating conditions.

Um die jeweiligen Relativstellungen der Induktorringe 19 zu den Induktorringgliedern 14 außerhalb der Presseurwalze 4 anzuzeigen, ragt ein Endabschnitt 25 des Rohrs 18, vorteilhafterweise an dem die Hochspannungszuführung 9 aufnehmenden Ende, axial aus einer der Lagerungsanordnungen 10 heraus, und ist mit Markierungen 27 versehen, die an einer ortsfesten Marke 28 (Fig. 2) die jeweils eingestellte Position der Induktorringe 19 sichtbar machen. Dadurch wird das jeweils gewünschte Zu- oder Abschalten eines bestimmten Induktorringgliedes 14 im Innenraum 8 der Presseurwalze 4 auf äußerst einfache Weise ermöglicht.In order to indicate the respective relative positions of the inductor rings 19 to the inductor ring members 14 outside the impression roller 4, an end section 25 of the tube 18, advantageously at the end receiving the high-voltage supply 9, projects axially out of one of the bearing arrangements 10 and is provided with markings 27 make the respectively set position of the inductor rings 19 visible at a fixed mark 28 (FIG. 2). This enables the desired switching on or off of a specific inductor ring member 14 in the interior 8 of the impression roller 4 in an extremely simple manner.

Die Lagerung bzw. Führung des Rohrs 18 in den Lagerzapfen 43 der Presseurwalze 4 kann so ausgebildet sein, daß beide axiale Enden des Rohrs 18 zur Außenseite der Presseurwalze hin offen sind. Bevorzugt wird jedoch, daß lediglich die Hochspannungszufuhrseite des in Fig. 2 rechten Lagerzapfens 43 eine den Zapfen vollständig durchsetzende Führung besitzt, während das in Fig. 2 linke Ende des Lagerzapfens 43 dicht zum Innenraum 8 der Presseurwalze 4 hin verschlossen ist. Bei dieser Ausführungsform ist, wie in Fig. 2 sichtbar, zwischen der Lagerungsanordnung 10 und dem aus ihr herausragenden Endabschnitt 25 des Rohrs 18 eine explosionssichere Dichtpackung 26 zum druckfesten Verschließen des Innenraums 8 der Presseurwalze 4 angebracht. Eine solche Dichtpackung muß einen im Innenraum 8 nach geltenden Explosionsschutzvorschriften aufzubauenden Überdruck standhalten oder eine im Innenraum gegebenenfalls vorhandene Schutzgasatmosphäre abdichten können. Damit bei einer an der Presseurwalze oder der Induktoreinrichtung 7 notwendig werdenden Wartung das mit den Induktorringen 19 bestückte Rohr 18 ohne weiteres aus dem Innenraum 8 der Presseurwalze 4 herausgezogen werden kann, ist es ferner von Vorteil, wenn der größte Durchmesser auf dem bestückten Rohr kleiner ist als die lichte Weite der axialen Rohrführung im Lagerzapfen 43.The storage or guidance of the tube 18 in the bearing pin 43 of the impression roller 4 can be designed such that both axial ends of the tube 18 are open to the outside of the impression roller. It is preferred, however, that only the high-voltage supply side of the bearing pin 43 on the right in FIG. 2 has a guide which completely penetrates the pin, while the left end of the bearing pin 43 in FIG. 2 is sealed off from the interior 8 of the impression roller 4. In this embodiment, as can be seen in FIG. 2, an explosion-proof sealing packing 26 is attached between the bearing arrangement 10 and the end section 25 of the tube 18 protruding therefrom for the pressure-tight sealing of the interior 8 of the impression roller 4. Such a sealing packing must be able to withstand an overpressure to be built up in the interior 8 according to the applicable explosion protection regulations or to be able to seal an inert gas atmosphere which may be present in the interior. So that when maintenance becomes necessary on the impression roller or inductor device 7, the tube 18 equipped with the inductor rings 19 can easily be pulled out of the interior 8 of the impression roller 4, it is also advantageous if the largest diameter on the equipped tube is smaller than the clear width of the axial pipe guide in the bearing pin 43.

Der bereits beschriebene Hohlzylinder- Wandungsaufbau 12 mit seinen wenigstens zwei äußeren Mänteln, dem Isolationsmantel 48 und der Außenmantelschicht 5 aus Halbleitermaterial, kann für unterschiedliche Einsatzmöglichkeiten der Presseurwalze 4 abgewandelt werden. Ein zweischichtiger Wandungsaufbau 12 ist in Fig. 4 gezeigt. Hier stehen die durch die Radialbohrungen 38. geführten Leitungsmittel 13 jeweils über Kontaktstellen 20 direkt mit der Schichtunterseite 21 der Außenmantelschicht 5 in Verbindung. Diese Kontaktstellen 20 können eine in Umfangsrichtung der Presseurwalze, ohne eine direkt leitende Verbindung untereinander zu besitzen, hintereinanderliegend aufgereiht sein oder durch einen in Fig. 1 gezeigten Ringleiter 22 zusammengeschlossen werden. Wird ein in Fig. 1 bis 3 dargestelltes Induktorringglied 14 bei einem Hohlkörper-Wandungsaufbau 12 nach Fig. 4 mit Kontaktstellen 20, die direkt an der Schichtunterseite 21 befestigt sind, induziert, werden von den Kontaktstellen 20 auf die Halbleiterschicht, je nach den gewählten Leitungseigenschaften des Schichtmaterials mehr oder weniger große Ladungszonen aufgebracht. Eine in Rotationsrichtung der Presseurwalze hintereinanderliegende Reihe von Kontaktstellen 20 ermöglicht mithin die Ausbildung einer Ringladungszone auf der Außenmantelschicht 5, was jeweils durch einen der ringsegmentförmigen Umfangsflächenabschnitte 36 in Fig. 4 angedeutet ist. Der außerhalb eines solchen Flächenabschnittes liegende Bereich der Presseurwalze verbleibt im wesentlichen frei von elektrostatischer Ladung. Möchte man (bei einem zweischichtigen Aufbau) mehrere Flächenbereiche 36 der Außenmantelschicht 5 gleichzeitig mit elektrostatischer Ladung versehen, können in Axialrichtung mehrere Segmente, etwa wie in Fig. 2 dargestellt, vorgesehen werden, so daß bei dem Zweischichtaufbau gemäß Fig. 4 eine in Axialrichtung der Presseurwalze aufeinanderfolgende Kette von Umfangsflächenabschnitten 36 elektrostatisch aufgeladen werden kann. Selbstverständlich könnte dann, wenn eine Presseurwalze während ihres Betriebs immer nur auf ihrer gesamten Breite oder in einem bestimmten unabänderbaren Breitenabschnitt elektrostatisch aufgeladen werden soll, ein einziges Induktorringglied 14 im Innenraum 8 untergebracht und zwischen der Außenmantelschicht 5 und dem Mantel 48 aus elektrischem IsoliermateriaL mit den Kontaktstellen 20 verbundene querlaufende Leiterbahnen, entsprechend der gewünschten Ladungsbreite auf der Walze, vorgesehen werden. Bei Verwendung nur eines Induktorringgliedes 14 erübrigt sich auch die beschriebene Axialverschiebung des Rohrs 18, und es genügt für die Hochspannungszuführung 9, die beispielsweise über ein Hochspannungskabel erfolgen kann, das Rohr 18 relativ zur Presseurwalze 4 drehbar zu führen. Eine weitere Möglichkeit zur elektrostatischen Ladungsverteilung auf bestimmte Umfangsflächenabschnitte der Presseurwalze besteht außer in dem Aufbringen von Querleitungen, wie gesagt, in der in Fig. 1 dargestellten ringförmigen Anordnung von Leitern 22 an der Schichtunterseite 21 der Außenmantelschicht 5. Solche Leiter 22, wie auch der vorgenannte Querleiter, können aus Draht, Leiterschichten, Leiterbahnen, leitenden Überzügen und dgl. ausgeführt werden.The already described hollow cylinder wall structure 12 with its at least two outer shells, the insulation sheath 48 and the outer sheath layer 5 made of semiconductor material, can be modified for different uses of the impression roller 4. A two-layer wall structure 12 is shown in FIG. 4. Here, the line means 13 guided through the radial bores 38 are each directly connected to the underside 21 of the outer jacket layer 5 via contact points 20. These contact points 20 can be arranged one behind the other in the circumferential direction of the impression roller, without having a direct conductive connection to one another, or can be connected by a ring conductor 22 shown in FIG. 1. If an inductor ring member 14 shown in FIGS. 1 to 3 is induced in a hollow body wall structure 12 according to FIG. 4 with contact points 20 which are fastened directly to the underside of the layer 21, the contact points 20 are applied to the semiconductor layer, depending on the selected line properties of the layer material applied more or less large charge zones. A row of contact points 20 lying one behind the other in the direction of rotation of the impression roller thus enables an annular charge zone to be formed on the outer jacket layer 5, which is indicated by one of the ring segment-shaped peripheral surface sections 36 in FIG. 4. The area of the impression roller lying outside such a surface section remains essentially free of electrostatic charge. If one would like (in a two-layer structure) to provide several surface areas 36 of the outer jacket layer 5 with electrostatic charge at the same time, several segments can be provided in the axial direction, for example as shown in FIG. 2, so that in the two-layer structure according to FIG Impression roller successive chain of peripheral surface portions 36 can be charged electrostatically. Of course, if an impression roller is to be charged electrostatically only over its entire width or in a certain unchangeable width section during operation, a single inductor ring member 14 could be accommodated in the interior 8 and between the outer jacket layer 5 and the jacket 48 made of electrical insulating material with the contact points 20 connected transverse conductor tracks, according to the desired charge width on the roller, are provided. If only one inductor ring member 14 is used, the described axial displacement of the tube 18 is also superfluous, and it is sufficient for the high-voltage feed 9, which can be carried out, for example, via a high-voltage cable, to rotate the tube 18 relative to the impression roller 4. Another possibility for electrostatic charge distribution on certain circumferential surface sections of the impression roller consists, in addition to the application of transverse lines, as mentioned, in the ring-shaped arrangement of conductors 22 shown on FIG. 1 on the underside 21 of the outer jacket layer 5. Such conductors 22, like the aforementioned one Transverse conductors can be made of wire, conductor layers, conductor tracks, conductive coatings and the like.

Wenn der Hohlzylinder-Wandungsaufbau 12 drei Außenschichten umfaßt, d. h., daß auf dem den Hohlzylinder 44 aus Metall überziehenden Mantel 48 aus elektrischem Isoliermaterial eine Leiterschicht 24, wie in Fig. 3 gezeigt, aufgebracht und auf diese wiederum die Außenmantelschicht 5 aus Halbleitermaterial aufgezogen ist, könnten alle Kontaktstellen 20 der Leitungsmittel 13 mit dieser Leiterschicht 24 verbunden sein. Dadurch würde die Ladung gleichförmig auf die gesamte Außenmantelschicht übertragen. Um bei einem solchen dreischichtigen Wandungsaufbau auch eine ringsegmentförmige Aufladung von einzelnen oder mehreren Umfangsflächenabschnitten vorzusehen, kann, wie in Fig. 2 dargestellt, die Leiterschicht 24 in drei Leiterbänder 23 unterteilt sein. Jedes dieser Leiterbänder 23 steht in Verbindung mit den Elektroden 16 bzw. den Leitungsmitteln 13 eines der drei Induktorringglieder 14, die sich im Innenraum 8 der Presseurwalze 4 befinden. Mittels der erläuterten Axialverschiebung des Rohres 18 können beim Anlegen von Hochspannung an sämtliche Induktorringglieder 14 alle drei Leiterbänder 23 ihre Ladung an die Außenmantelschicht abgeben. Damit über die gesamte Breite einerseits beim Betrieb sämtlicher vorgesehener Induktorringglieder 14 eine gleichförmige Ladungsverteilung stattfindet und andererseits beim Induzieren von Hochspannung an einem oder an mehreren jedoch nicht an allen Induktorringgliedern sichergestellt ist, daß nur die jeweils mit Spannung versorgten Leiterbänder 23 den gewünschten Umfangsflächenabschnitt der Außenmantelschicht 5 aufladen, ist zwischen benachbarten Rändern der Leiterbänder 23 ein solcher Abstand A vorzusehen, daß unter Berücksichtigung von einschlägigen Material- und Spannungswerten ein optimaler Kompromiß zwischen sämtlichen möglichen Betriebsarten geschlossen werden kann.If the hollow cylinder wall structure 12 comprises three outer layers, that is to say that a conductor layer 24, as shown in FIG. 3, is applied to the jacket 48 made of electrical insulating material and covering the metal hollow cylinder 44, and the outer jacket layer 5 made of semiconductor material is in turn applied thereon. All contact points 20 of the line means 13 could be connected to this conductor layer 24. This would transfer the charge uniformly to the entire outer jacket layer. To such a three-layer To provide a wall segment-like charging of individual or more peripheral surface sections, the conductor layer 24 can be divided into three conductor strips 23, as shown in FIG. 2. Each of these conductor strips 23 is connected to the electrodes 16 or the line means 13 of one of the three inductor ring members 14, which are located in the interior 8 of the impression roller 4. By means of the described axial displacement of the tube 18, all three conductor strips 23 can release their charge to the outer jacket layer when high voltage is applied to all inductor ring members 14. So that a uniform charge distribution takes place over the entire width on the one hand when operating all the inductor ring members 14 provided and on the other hand when inducing high voltage on one or more but not all inductor ring members it is ensured that only the conductor strips 23 supplied with voltage in each case have the desired peripheral surface section of the outer jacket layer 5 charge, a distance A must be provided between adjacent edges of the conductor strips 23 such that an optimal compromise can be made between all possible operating modes, taking into account relevant material and voltage values.

Gemäß einer weiteren Variante sind die Leiterbänder 23 beim dreischichtigen Hohlzylinder- Wandungsaufbau 12 nach Fig. 2 in Axialrichtung der Presseurwalze 4 unterteilt, so daß, wie im unteren Teil von Fig. 1 gezeigt, eine in Laufrichtung der Walze hintereinanderliegende Reihe von Umfangssektoren 58 ausgebildet wird. Der Abstand zwischen jeweils benachbarten Umfangssektoren 58 kann dem Abstand A zwischen Leiterbändern 23 in Fig. 2 entsprechen. Dieser Hohlzylinder-Wandungsaufbau eignet sich besonders für eine elektrostatische Aufladung eines hauptsächlich querliegenden Feldes auf der Außenmantelschicht 5, d. h. eines sich über eine oder mehrere axial nebeneinanderliegende Reihe oder Reihen von Umfangssektoren 58 erstreckenden Feldes, während der restliche Umfang der Presseurwalze 4 im wesentlichen ladungsfrei bleiben kann.According to a further variant, the conductor strips 23 in the three-layer hollow cylinder wall structure 12 according to FIG. 2 are subdivided in the axial direction of the impression roller 4, so that, as shown in the lower part of FIG. 1, a row of circumferential sectors 58 lying one behind the other in the running direction of the roller is formed . The distance between adjacent circumferential sectors 58 can correspond to the distance A between conductor strips 23 in FIG. 2. This hollow cylinder wall structure is particularly suitable for electrostatic charging of a mainly transverse field on the outer jacket layer 5, i. H. a field extending over one or more axially adjacent rows or rows of circumferential sectors 58, while the remaining circumference of the impression roller 4 can remain essentially free of charge.

Für eine derartige Aufladung eignet sich eine abgewandelte Ausführungsform der Induktoreinrichtung 7, wie sie in den Fig. 3a und 3b gezeigt ist. Fig. 3b zeigt eine schematische Ansicht der Variante nach Fig. 3a in Richtung des dort eingezeichneten Pfeils 3b gesehen. Bei dieser Variante besteht der anhand von Fig. 3 erläuterte Induktorring 19 aus mindestens einem Induktor-Ringsegment 51, das, wie Fig. 3b zeigt, lediglich auf einem Teil des Umfangs des Rohres 18 vorgesehen ist. Der verbleibende Umfangsbereich des Induktorringes 19 besteht aus Isoliermaterial, vorzugsweise aus dem des Rohres 18. Das Induktor-Ringsegment 51 besitzt eine Breite in Axialrichtung des Rohres 18, die etwa der Breite des Induktorrings 19 nach Fig. 3 entspricht und erstreckt sich in Radialrichtung des Rohres 18 über einen Segmentwinkel, der etwa 1/4 oder 1/3 des Rohres, d. h. 90° bis 120° seines Umfangs abdeckt. Das Ringsegment 51 kann in die Oberfläche des Rohrs 18 eingearbeitet, mit dieser verklebt oder in diese eingegossen sein. Jedes Induktor-Ringsegment 51 ist, wie bei der Ausführungsform gemäß Fig. 3, an die Hochspannungszuführung 9 angeschlossen. Entsprechend sind auch die Ringsegmente 51 mittels des Rohrs 18 axialverschiebbar und ihre Relativstellung wird, wie anhand der Ausführungsform nach Fig. 3 beschrieben, außerhalb der Presseurwalze 4 angezeigt. Befinden sich mehrere Induktor-Ringsegmente 51 auf dem Rohr 18, so sind sie in Axialrichtung des Rohrs zueinander fluchtend angeordnet.A modified embodiment of the inductor device 7, as shown in FIGS. 3a and 3b, is suitable for such charging. FIG. 3b shows a schematic view of the variant according to FIG. 3a seen in the direction of the arrow 3b drawn there. In this variant, the inductor ring 19 explained with reference to FIG. 3 consists of at least one inductor ring segment 51 which, as shown in FIG. 3b, is only provided on part of the circumference of the tube 18. The remaining peripheral region of the inductor ring 19 consists of insulating material, preferably that of the tube 18. The inductor ring segment 51 has a width in the axial direction of the tube 18 which corresponds approximately to the width of the inductor ring 19 according to FIG. 3 and extends in the radial direction of the tube 18 over a segment angle that is about 1/4 or 1/3 of the tube, i.e. H. Covers 90 ° to 120 ° of its circumference. The ring segment 51 can be worked into the surface of the tube 18, glued to it or cast into it. As in the embodiment according to FIG. 3, each inductor ring segment 51 is connected to the high-voltage feed 9. Correspondingly, the ring segments 51 are also axially displaceable by means of the tube 18 and their relative position, as described with reference to the embodiment according to FIG. 3, is displayed outside the impression roller 4. If there are several inductor ring segments 51 on the tube 18, they are arranged in alignment with one another in the axial direction of the tube.

Damit die hochspannungsführenden Ringsegmente 51 auf dem Rohr 18 hauptsächlich den jeweils im Umgebungsbereich des Druckspalts 6 befindlichen Abschnitt der Außenmantelschicht 5 der Presseurwalze 4 elektrostatisch aufladen, sind die Ringsegmente 51 auf diejenigen Elektroden 16 bzw. deren Elektrodenspitzen 17 ausgerichtet, welche sich im Umgebungsbereich des Druckspalts 6 befinden bzw. sich in diesen hineinbewegen. Beispielsweise könnten bei der Drehung der Presseurwalze 4 in Richtung des Pfeils II in Fig. 1, die in einer Reihe auf dem Rohr 18 zueinander fluchtenden Ringsegmente 51 an der Stelle X in Fig. 1 angeordnet sein, um dort die in den Umgebungsbereich des Druckspalts einlaufenden Elektrodenspitzen 17 mit ihren zugehörigen Elektroden 16 zu induzieren, so daß die übertragene Hochspannung nur auf den in Drehrichtung vor dem Druckspalt 6 liegenden Abschnitt der Außenmantelschicht 5, vorteilhafterweise über die Umfangssektoren 58, aufgebracht wird.So that the high-voltage ring segments 51 on the tube 18 mainly electrostatically charge the section of the outer jacket layer 5 of the impression roller 4 that is located in the vicinity of the pressure gap 6, the ring segments 51 are aligned with those electrodes 16 or their electrode tips 17 that are located in the vicinity of the pressure gap 6 are located or move into it. For example, when the impression roller 4 rotates in the direction of the arrow II in FIG. 1, the ring segments 51 which are aligned in a row on the tube 18 could be arranged at the point X in FIG. 1 in order to there enter the surrounding area of the pressure gap To induce electrode tips 17 with their associated electrodes 16, so that the transmitted high voltage is only applied to the section of the outer jacket layer 5 lying in the direction of rotation in front of the pressure gap 6, advantageously over the peripheral sectors 58.

Sobald dieser elektrostatisch aufgeladene Abschnitt den Druckspalt 6 durchläuft, wirkt seine Ladung auf die Substratbahn 3 und die Druckfarbübertragung ein und wird über den geerdeten Druckzylinder 2 abgeleitet. Nach dem Durchlauf des elektrostatisch aufgeladenen Abschnitts der Außenmantelschicht 5 durch den Druckspalt 6 ist die Außenmantelschicht im wesentlichen ladungsfrei und bleibt dies auch, bis sie wieder etwa bis zur Stelle X gelaufen ist. Dieses Freihalten der Oberfläche der Presseurwalze 4 von elektrostatischer Ladung in dem außerhalb des für den Druckvorgang benötigten Walzenabschnitts liegenden Bereich der Presseurwalze bietet den besonderen Vorteil, daß die Außenmantelschicht 5 aus der Umgebung kaum noch schichtverunreinigende Partikel anziehen kann. Vorteilhafterweise könnte auch der an der Auslaufseite der Substratbahn 3 in Fig. 1 gezeigte lonisator 47 entfallen.As soon as this electrostatically charged section passes through the printing nip 6, its charge acts on the substrate web 3 and the ink transfer and is discharged via the grounded printing cylinder 2. After the electrostatically charged section of the outer jacket layer 5 has passed through the pressure gap 6, the outer jacket layer is essentially charge-free and remains so until it has again run approximately to point X. This keeping the surface of the impression roller 4 free of electrostatic charge in the area of the impression roller lying outside the roller section required for the printing process offers the particular advantage that the outer jacket layer 5 can hardly attract layer-contaminating particles from the environment. The ionizer 47 shown on the outlet side of the substrate web 3 in FIG. 1 could advantageously also be omitted.

Damit die hochspannungszuführenden Ringsegmente 51 in Rotationsrichtung der Presseurwalze 4 entsprechend den geforderten Betriebsbedingungen verstellt werden können, läßt sich das die Ringsegmente 51 tragende Rohr 18 relativ zur Presseurwalze drehen. Der Endabschnitt 25 des Rohres 18, das, wie in Fig. 2 gezeigt, axial auf einer der Lagerungsanordnungen 10 herausgeführt ist, eignet sich auch für ein gezieltes Verdrehen des Rohrs 18 und damit zur Einstellung des Drehwinkels der Ringsegmente 51, z. B. bezogen auf die Mitte des Druckspalts 6. Um die genaue Winkelstellung der Segmente 51 im Inneren der Presseurwalze 4 anzuzeigen, ist, wie in Fig. 2 dargestellt, auf dem herausragenden Endabschnitt 25 des Rohres 18 zusätzlich zu den Markierungen 27 eine Gradeinteilung aufgebracht, die über eine ortsfeste Drehstellungsmarkierung 53 die jeweilige Drehstellung der Ringsegmente 51 wiedergibt.So that the high voltage supplying ring segments 51 can be adjusted in the direction of rotation of the impression roller 4 in accordance with the required operating conditions, the tube 18 carrying the ring segments 51 can be rotated relative to the impression roller. The end portion 25 of the tube 18 which, as in FIG. 2 shown, axially led out on one of the bearing arrangements 10, is also suitable for a targeted rotation of the tube 18 and thus for adjusting the angle of rotation of the ring segments 51, for. B. in relation to the center of the pressure gap 6. In order to indicate the exact angular position of the segments 51 inside the impression roller 4, in addition to the markings 27, a graduation is applied to the protruding end section 25 of the tube 18, as shown in FIG. 2, which reproduces the respective rotary position of the ring segments 51 via a fixed rotary position marker 53.

Die in Fig. 4 gezeigte Ausführungsform einer hohlzylindrischen Presseurwalze 4 mit elektrostatischer Druckhilfe besitzt, wie gesagt, einen zweischichtigen Außenmantel auf dem Hohlzylinder 44. Bei diesem Ausführungsbeispiel ist der Mantel 48 aus elektrischem Isoliermaterial über die stirnseitigen Flächen des Lagerzapfens 43 heruntergeführt, um ein randseitiges Abfließen der Ladung von der elektrostatisch aufladbaren Außenmantelschicht 5 zu der geerdeten Lagerungsanordnung 10 auszuschließen. Die spezielle Ausführungsart und das Ausmaß, in dem der Isoliermantel 48 über die Stirnseiten der Presseurwalze heruntergezogen wird, richtet sich nach den betrieblichen Hochspannungswerten sowie den gewählten Materialien. Der Hohlzylinder 44 ist, wie in Fig. 4 gezeigt, mit einer dem Mantel 48 entsprechenden Innenflächenisolation 50 versehen, so daß die den Innenraum 8 umschließende Wandfläche 11 von der Innenseite der Isolation 50 gebildet wird.The embodiment of a hollow cylindrical impression roller 4 with electrostatic pressure aid shown in FIG. 4 has, as mentioned, a two-layer outer jacket on the hollow cylinder 44. In this embodiment, the jacket 48 made of electrical insulating material is led down over the end faces of the bearing pin 43 in order to drain off at the edge to exclude the charge from the electrostatically chargeable outer jacket layer 5 to the grounded mounting arrangement 10. The particular design and the extent to which the insulating jacket 48 is pulled down over the end faces of the impression roller depends on the operational high voltage values and the materials selected. As shown in FIG. 4, the hollow cylinder 44 is provided with an inner surface insulation 50 corresponding to the jacket 48, so that the wall surface 11 surrounding the interior 8 is formed from the inside of the insulation 50.

Die Induktoreinrichtung 7 wird bei dieser Ausführungsform von einem Induktorscheibenglied 31 gebildet, welches einen kreisförmigen Elektrodenträger 32 aufweist, in dem mehrere Elektroden 33 in Umfangsrichtung verteilt hochspannungsfest isoliert eingebettet sind. Die bei der Ausführungsform nach den Fig. 1 bis 3 zur Rotationsachse R der Presseurwalze 4 hin ausgerichteten Elektrodenspitzen 17 sind bei der Ausführungsform nach Fig. 4 zur Wandinnenfläche 11 hin von der Rotationsachse R nach außen gerichtet angeordnet und bilden die Elektrodenspitzen 34. Diese Elektrodenspitzen 34 liegen auf einem zur Wandinnenfläche 11 konzentrischen imaginären Kreis K'. Das Induktorscheibenglied 31 sitzt drehfest auf einer Hohlwelle 30, die ähnlich dem Rohr 18 aus Isoliermaterial bestehen. kann, und die Hochspannungszuführung 9 wird durch die Hohlwelle 30 zu den Elektroden 33 geleitet. In dieser Zuführung befinden sich elektrische Koppelelemente 49. An dem den Elektrodenspitzen 34 gegenüberliegenden Bereich der Innenflächenisolation 50 ist in Rotationsrichtung der Presseurwalze 4 umlaufend eine Reihe aus Kontaktelementen 35 angebracht, die mit den durch die Radialbohrungen 38 im Mantel 48 zur Außenmantelschicht 5 hindurchgeführten Leitungsmitteln 13 in Verbindung stehen. Diese Kontaktelemente 35 können als geschlossene Ringe, die aus einem ähnlichen Material bestehen wie die Induktorringe 19, an der Innenflächenisolation 50 konzentrisch entlanglaufend angebracht sein und mehrere oder sämtliche Leitungsmittel 13, die in einer Radialebene liegen, miteinander verbinden. Wie in Fig. 4 angedeutet, können auf der Hohlwelle 30 auch mehrere Induktorscheibenglieder 31, die untereinander und von den innenseitigen Teilen der Lagerungsanordnungen 10 axiale Abstände besitzen, angeordnet werden. Auch wäre es bei dieser Ausführungsform möglich, jedem Induktorscheibenglied 31 mehrere nebeneinanderliegende Kontaktelemente 35 entsprechend der Induktorringteilung gemäß Fig. 2 vorzusehen und die Induktorscheibenglieder 31 relativ zu den Kontaktelementen 35 bzw. zu nicht von Kontaktelementen überdeckten Bereichen der Innenflächenisolation 50 axial verschiebbar zu gestalten, um so eine segmentweise Ansteuerung einzelner oder mehrerer Umfangsflächenabschnitte 36 auf der Außenmantelschicht 5 erreichen zu können. Hinsichtlich der Abdichtmaßnahmen zwischen der Hohlwelle 30 und dem Lagerzapfen 43 gelten die gleichen Kriterien wie bei der Ausführungsform nach den Fig. 1 bis 3 beschrieben.In this embodiment, the inductor device 7 is formed by an inductor disk member 31 which has a circular electrode carrier 32, in which a plurality of electrodes 33 are embedded, insulated in a circumferential direction and insulated from high voltage. The electrode tips 17 oriented towards the axis of rotation R of the impression roller 4 in the embodiment according to FIGS. 1 to 3 are arranged toward the outside of the axis of rotation R towards the inside wall 11 in the embodiment according to FIG. 4 and form the electrode tips 34. These electrode tips 34 lie on an imaginary circle K 'concentric with the inner wall surface 11. The inductor disc member 31 is non-rotatably seated on a hollow shaft 30 which, similar to the tube 18, is made of insulating material. can, and the high-voltage feed 9 is passed through the hollow shaft 30 to the electrodes 33. In this feed there are electrical coupling elements 49. On the area of the inner surface insulation 50 opposite the electrode tips 34, a row of contact elements 35 is attached all the way around in the direction of rotation of the impression roller 4, which contact elements 13 lead into the outer jacket layer 5 through the radial holes 38 in the jacket 48 Connect. These contact elements 35 can be attached as closed rings, which are made of a similar material to the inductor rings 19, concentrically along the inner surface insulation 50 and can connect several or all of the line means 13, which lie in a radial plane, to one another. As indicated in FIG. 4, a plurality of inductor disk members 31, which have axial distances from one another and from the inner parts of the bearing arrangements 10, can also be arranged on the hollow shaft 30. It would also be possible in this embodiment to provide each inductor disc member 31 with a plurality of contact elements 35 lying next to one another in accordance with the inductor ring division according to FIG. 2, and to make the inductor disc members 31 axially displaceable relative to the contact elements 35 or to areas of the inner surface insulation 50 not covered by contact elements, so that to be able to achieve segment-wise control of individual or a plurality of peripheral surface sections 36 on the outer jacket layer 5. With regard to the sealing measures between the hollow shaft 30 and the bearing pin 43, the same criteria apply as described in the embodiment according to FIGS. 1 to 3.

In den Fig. 4a und 4b ist eine Variante der in Fig. 4 gezeigten Induktoreinrichtung 7 abgebildet, die einenquergerichteten Ladungsauftrag auf die Außenmantelschicht 5 aufbringen kann. Der zweischichtige Wandungsaufbau 12 der Presseurwalze 4 nach Fig. 4 eignet sich vorteilhaft zum Aufbau elektrostatischer Ladungszonen in der Umgebung der jeweiligen Kontaktstellen 20 an der Unterseite 21 der Außenmantelschicht 5, welche je nach der Art des verwendeten Halbleitermaterials und der induzierten Spannung mehr oder weniger große Ladungszonen bereitstellen kann. Die Ladungsverteilung in diesen Zonen nimmt, ausgehend von der jeweiligen Kontaktstelle, ab, so daß zwischen benachbarten Ladungszonen praktisch Abschnitte geringer bis sehr kleiner Ladung gebildet werden. Diese Zonen stellen in Lauf- und Axialrichtung der Presseurwalze eine Art Ladungsgitterstruktur dar. Wenn nun die mit den jeweiligen Kontaktstellen 20 verbundenen Kontaktelemente 35 im Innenraum der Presseurwalze in Form einer axialen Reihe, d. h. über die Breite der Walze, induziert werden, trägt nur der an diesen Kontaktstellen 20 angeschlossene Bereich des Außenmantels die elektrostatische Ladung, während der restliche Teil des Walzenumfangs im wesentlichen ladungsfrei bleibt. Auch mit den bereits erwähnten querlaufenden Leiterbahnen ließe sich eine derartige Aufteilung der in Umfangs- und Axialrichtung der Presseurwalze voneinander ladungsmäßig unterscheidbaren Ladungszonen ausführen.4a and 4b show a variant of the inductor device 7 shown in FIG. 4, which can apply a transverse charge application to the outer cladding layer 5. The two-layer wall structure 12 of the impression roller 4 according to FIG. 4 is advantageously suitable for the construction of electrostatic charge zones in the vicinity of the respective contact points 20 on the underside 21 of the outer jacket layer 5, which, depending on the type of semiconductor material used and the induced voltage, have more or less large charge zones can provide. The charge distribution in these zones decreases, starting from the respective contact point, so that practically sections of low to very small charge are formed between adjacent charge zones. These zones represent a kind of charge grid structure in the running and axial directions of the impression roller. If the contact elements 35 connected to the respective contact points 20 in the interior of the impression roller in the form of an axial row, i. H. across the width of the roller, only the area of the outer jacket connected to these contact points 20 carries the electrostatic charge, while the remaining part of the roller circumference remains essentially charge-free. Such a division of the charge zones which are distinguishable from one another in the circumferential and axial directions of the impression roller can also be carried out with the transverse conductor tracks already mentioned.

Bei der Ausführungsform nach den Fig. 4a und 4b sind mehrere Elektroden 33 eines Induktorscheibenglieds 31 in einem Segment 54 des Scheibenglieds vorgesehen. Dieses Segment, das auch so ausgeführt sein kann, daß der nicht mit den Elektroden bestückte Teil des Induktorscheibenglieds entfällt, ist im Innenraum 8 der hohlzylindrischen Presseurwalze 4 auf diejenigen Kontaktelemente 35 ausgerichtet, welche die Ladung jeweils auf den im Umgebungsbereich des Druckspalts 6 befindlichen Abschnitt der Außenmantelschicht 5 übertragen.In the embodiment according to FIGS. 4a and 4b, a plurality of electrodes 33 of an inductor disk member 31 are provided in a segment 54 of the disk member. This segment, which can also be designed so that the part of the inductor disc member which is not equipped with the electrodes is omitted, is in the interior 8 of the hollow cylindrical impression roller 4 to those cones Aligned clock elements 35, which each transfer the charge to the section of the outer jacket layer 5 located in the vicinity of the pressure gap 6.

Bei mehreren auf der Hohlwelle 30 vorgesehenen Induktorscheibengliedern 31 sind sämtliche Segmente 54 in Axialrichtung der Welle zueinander fluchtend angeordnet. Die in der Axialrichtung gleichzeitige Induktion über die Elektroden 33 bewirkt eine entsprechende Ladungsverteilung auf der Außenmantelschicht 5. Vorzugsweise umfaßt der durch das jeweilige Scheibengliedsegment 54 gebildete hochspannungszuführende Abschnitt einen Segmentwinkel β von etwa 90° bis 120°. Die Zuführung der Hochspannung 9 erfolgt, wie bei der Ausführungsform nach Fig. 4, durch die Hohlwelle 30. Um die jeweilige Drehstellung des Segments 54 bzw. der ganzen Segmentreihe im Innenraum 8 der Presseurwalze 4 anzeigen zu können, ist die Hohlwelle 30 an ihrem aus der Lagerungsanordnung 10 herausragenden Abschnitt 55 mit einer Gradeinteilung 56 versehen (Fig. 4), die an einer geeigneten ortsfesten Drehstellungsmarkierung 57 die jeweilige Position des Segments 54 sichtbar macht.In the case of a plurality of inductor disk members 31 provided on the hollow shaft 30, all segments 54 are arranged in alignment with one another in the axial direction of the shaft. The simultaneous induction in the axial direction via the electrodes 33 results in a corresponding charge distribution on the outer cladding layer 5. The high-voltage-supplying section formed by the respective disk link segment 54 preferably comprises a segment angle β of approximately 90 ° to 120 °. The high voltage 9 is supplied, as in the embodiment according to FIG. 4, through the hollow shaft 30. In order to be able to display the respective rotational position of the segment 54 or the entire row of segments in the interior 8 of the impression roller 4, the hollow shaft 30 is off on it of the bearing arrangement 10 projecting section 55 with a graduation 56 (FIG. 4), which makes the respective position of the segment 54 visible at a suitable fixed rotational position marking 57.

Diese Verstellbarkeit der Segmente 54 erlaubt auch bei laufendem Druckwerk eine Veränderung der Breite der Ladungsfläche auf dem Außenmantel in der Laufrichtung, bezogen auf den Druckspalt, wodurch die Druckqualität ein- . gestellt bzw. korrigiert werden kann.This adjustability of the segments 54 allows a change in the width of the cargo area on the outer jacket in the running direction, with respect to the printing nip, even when the printing unit is running, thereby reducing the printing quality. can be made or corrected.

Bei der Querschnittansicht gemäß Fig. 1 sind im Hohlzylinder 44 über einen Viertelkreis verteilt drei Radialbohrungen 38 vorgesehen. Bei der dargestellten Einteilung ergäben sich über den gesamten Umfang gleichmäßig verteilt acht Radialbohrungen. Die Auswahl der Anzahl der Radialbohrungen hängt von verschiedenen Faktoren ab. So darf z. B. die Tragfähigkeit des Hohlzylinders 44, der beim Einsatz in einem Druckwerk starken Beanspruchungen ausgesetzt ist, durch die Bohrungen nicht zu stark geschwächt werden. Aus diesem Grunde möchte man möglichst wenige Bohrungen vorsehen. Nun ist aber eine gewisse Mindestanzahl an Hochspannungs-Zuführungsstellen zur Außenmantelschicht 5 erforderlich um die verlangte elektrostatische Ladung übertragen und auf dem Halbleiter möglichst gleichmäßig bzw. in der gewünschten Breite verteilen zu können. Da sich ferner die Außenmantelschicht entsprechend dem Durchmesser der Presseurwalze ändert, muß die Bestimmung einer optimalen Anzahl an Radialbohrungen auch für jeden Durchmesser erfolgen. Für die derzeit zum Einsatz kommenden Presseurwalzen werden mindestens vier und höchstens zwölf Radialbohrungen 38 über den Umfang verteilt in einer Radialebene liegend vorgesehen.1, three radial bores 38 are provided in the hollow cylinder 44 distributed over a quarter circle. In the division shown, there would be eight radial holes evenly distributed over the entire circumference. The selection of the number of radial bores depends on various factors. So z. B. the load capacity of the hollow cylinder 44, which is exposed to severe stresses when used in a printing unit, not weakened too much by the holes. For this reason, one would like to provide as few holes as possible. However, a certain minimum number of high-voltage supply points to the outer cladding layer 5 is now required in order to be able to transmit the required electrostatic charge and to be able to distribute it on the semiconductor as evenly as possible or in the desired width. Furthermore, since the outer jacket layer changes in accordance with the diameter of the impression roller, the optimum number of radial bores must also be determined for each diameter. At least four and a maximum of twelve radial bores 38 distributed over the circumference are provided lying in a radial plane for the impression rollers currently used.

Claims (20)

1. Printing device with additional electrostatic field for assisting the colour transfer from a printing cylinder (2) onto a dielectric substrate web (3) in a printing gap (6) formed between the printing cylinder surface and an electrostatically chargeable outer sheathing layer (5) of a hollow-cylindrical impression roller (4), with the outer sheathing layer (5), for the electrostatic charging of at least one section of the outer sheathing layer (5) of the impression roller (4), which section is in each case moved through the printing gap, being loaded with a high voltage which is fed into the inner space (8) of the impression roller (4) via a highvoltage lead (9) guided through at least one of the endface bearing arrangements (10) of the impression roller (4), and with conducting means (13) which are firmly insulated against high voltage and are guided through the hollow-cylindrical wall construction of the impression roller (4) being available between the inner space of the impression roller (4) and its electrostatically chargeable outer sheathing layer (5), which conducting means (13) are connected at least in sections to the outer sheathing layer (5), characterized by an inductor device (7) for loading the outer sheathing layer (5), which inductor device (7) is provided in the inner space (8) of the hollow-cylindrical impression roller (4).
2. Printing device according to claim 1, characterized in that the inductor device (7) has at least one inductor ring member (14) attached to the surface (11) of the wall construction (12), which surface (11) defines the inner space (8) of the impression roller (4), that this ring member has an annular-shaped electrode holder (15) into which several electrodes (16) are embedded in such a way, in a manner firmly insulated against high voltage, one after the other in the direction of rotation of the impression roller and distributed at approximately equally large distances over the periphery of the ring member, that their electrode tips (17) lie on an imaginary circle (K) concentric to the axis (R) of rotation of the impression roller, that each electrode is connected to a conducting means (13) guided through the hollow-cylindrical wall construction (12), that the high-voltage lead (9) is inserted into the inner space (8) of the impression roller through a tube (18) which is coaxial to the axis (R) of rotation and at least projects into the circle (K) formed by the electrode tips (17), that this tube, on a periphery section facing towards the electrode tips, carries at least one inductor ring (19) which is connected to the high voltage lead and the outer diameter of which, for a contactless charge transfer, is smaller than the circle (K) formed by the electrode tips.
3. Printing device according to claim 2, characterized in that, in the inner space (8) of the impression roller (4), several inductor ring members (14) are arranged at mutual axial distances from one another and from the inner-space side parts of the bearing arrangements (10), that the electrodes (16) of each inductor ring member, via the conducting means (13) allocated to them, are connected to contact points (20) provided on the layer underside (21) of the outer sheathing layer (5) of the impression roller, that the tube (18) is mounted in rotatable and axially displaceable manner relative to the impression roller, that several inductor rings (19) are arranged at such axial distances from one another on the tube (18) that, in various axial positions of the tube, one inductor ring member or one inductor ring each is located radially opposite either each inductor ring member, several inductor ring members or one inductor ring member, and that the inductor rings are connected to the high-voltage lead (9) in such a way that at least the inductor ring(s) located in each case opposite the inductor ring members transfers its charge to the electrodes (16) which feeds it at least to one annular peripheral section of the outer sheathing layer (5) via the conducting means (13) and the contact points (20).
4. Printing device according to claim 3, characterized in that the radial distance between the circle (K) occupied by the electrode tips (17) and the high-voltage conducting surface of an inductor ring (19) in alignment with an inductor ring member (14) is smaller than the minimum axial distance between two adjacent, high-voltage- conducting inductor rings.
5. Printing device according to claim 2, with the conducting means (13) which are connected in sections to the outer sheathing layer (5) of the impression roller (4) developing, via the contact points (20), on the outer sheathing layer (5), charge-conducting peripheral sectors (58) which are interrupted at least in the peripheral direction of the impression roller (4) by sections of smaller charge conductivity, characterized in that the inductor ring (19) consists of at least one inductor ring segment (51) provided on a part of the periphery of the tube (18) and otherwise consists of insulating material, and that this ring segment, in the inner space (8) of the hollow-cylindrical impression roller (4), is aligned with those electrodes (16), or their electrode tips (17), which electrostatically charge the section of the outer sheathing layer (5), which section is located in each case in the surrounding area of the printing gap (6) and contains the peripheral sectors (58).
6. Printing device according to claim 5, characterized in that, when several inductor rings (19) are provided on the tube (18), the charge-conducting peripheral sectors (58) are arranged in alignment with one another in the axial direction of the tube, and that the section supplying high voltage and formed by the respective ring segment covers a segment angle (α) of the tube (18) of about 90°-120°.
7. Printing device according to one of claims 2 to 6, characterized in that the electrodes (16) bearing the electrode tips (17) are embedded into the electrode holder (15) in such a way that its annular-surface lateral boundary (37) is guided radially towards the tube (18) at least up to the circle (K) occupied by the electrode tips.
8. Printing device according to claim 3, characterized in that all contact points (20) of the conducting means (13) of each inductor ring member (14) are connected to a conductor (22) which is closed in the peripheral direction of the impression roller (4) and is in contact with the layer underside (21) of the outer sheathing layer (5).
9. Printing device according to claim 8, characterized in that the conductor (22) is made as a conductor strip (23) and has such a width that, when conductor strips are located next to one another in the axial direction of the impression roller (4) in accordance with the number of inductor ring members (14), there is a distance (A) between adjacent peripheral edges of such conductor strips.
10. Printing device according to claim 8, characterized in that the contact points (20) of the conducting means (13) of several inductor ring members (14) are connected to a conductor layer (24) applied to the entire layer underside (21) of the outer sheathing layer (5).
11. Printing device according to one of claims 3 to 10, characterized in that the tube (18) containing the high-voltage lead (9) and carrying the inductor rings (19) is guided in the end-face bearing arrangements (10) of the impression roller (4) concentrically to the axis (R) of rotation, that at least one end section (25) of the tube projects axially from one of the bearing arrangements and this end section accommodates the high-voltage lead (9), that the largest diameter on the tube fitted with the inductor rings is smaller than the inside diameter at least of the tube guide mounting the end section (25), and that an explosion proof packing (26) for the pressure-resistant closing of the inner space (8) of the impression roller (4) is provided between the bearing arrangement (10) and the tube end section projecting from the latter.
12. Printing device according to claim 11, characterized in that the tube (18) is made of insulating material, and that the inductor rings (19) are made of a material which is resistant to corrosion and electrolytic collapse.
13. Printing device according to claim 11 or 12, characterized in that the end section (25) of the tube (18), which end section (25) projects from the bearing arrangement (10), has a length which corresponds at least to the longest displacement of the inductor rings (19) relative to the inductor ring members (14) inside the roller, and that markings (27) are provided on the projecting end section which, at a fixed mark (28) outside the impression roller (4), indicate the respective relative positions of the inductor rings to the inductor ring members.
14. Printing device according to claim 5 and 13, characterized in that a degree graduation (52) is applied to the projecting end section (25) of the tube (18) in addition to the markings (27), which degree graduation (52), via a fixed rotary-position of the ring segments (51) with respect to the centre of the printing gap (6).
15. Printing device according to claim 1, characterized in that the inductor device (7) has at least one inductor disc member (31) which is attached on a hollow shaft (30), mounted coaxially to the impression roller, and has a circular electrode holder (32) into which several electrodes are embedded in such a way, in a manner firmly insulated against high voltage and distributed in peripheral direction, that their electrode tips (34), pointing towards the wall inner surface (11) of the inner space (8), lie on an imaginary circle (K') concentric to this surface, that the electrodes (33) are connected to the high-voltage lead (9) inserted through the hollow shaft, and that a row of contact elements (35), which row encircles in the direction of rotation of the impression roller (4), is provided on the peripheral area of the wall inner surface (11) opposite their electrode tips (34), which contact elements (35) are firmly insulated against high voltage, are connected to the conducting means (13) and transfer the charge, transferred by the electrodes, from the inner space (8) of the impression roller (4) at least to a ring-segment-shaped peripheral section (36) of the outer sheathing layer (5).
16. Printing device according to claim 15, characterized in that several inductor disc members (31) are provided on the hollow shaft (30) at mutual axial distances from one another and from the inner-space side parts of the bearing arrangements (10), that a row of contact elements (35) is located opposite each inductor disc member, which contact elements (35) are in each case in contact in rows with a ring-segment-shaped peripheral surface section (36) of the outer sheathing layer (5), and that each inductor disc member (31) connected to the high-voltage lead (9) or all of or a part of the electrodes (33) carried by the inductor disc member (31) can alternatively be connected onto and disconnected from the high-voltage lead.
17. Printing device according to claim 15 or 16, with the conducting means (13) which are connected in sections to the outer sheathing layer (5) of the impression roller (4) developing, via the contact points (20), on the outer sheathing layer (5), charge zones for the desired charge intensity, which charging zones are interrupted from one another in the peripheral direction and in the axial direction of the impression roller (4) by sections of smaller charge conductivity, characterized in that several electrodes (33) of an inductor disc member (31) are provided in an angle segment (54) of the disc member, and that this disc-member angle segment, in the inner space (8) of the hollow-cylindrical impression roller (4), is aligned with those contact elements (35) which electrostatically charge the section of the outer sheathing layer having the charge zones, which section is located in each case in the surrounding area of the printing gap (6).
18. Printing device according to claim 17, characterized in that, when several inductor disc members (31) are provided on the hollow shaft (30), all angle segments (54) are arranged in alignment with one another in the axial direction of the shaft, and that the section conducting high voltage and formed by the respective angle segment (54) encloses a segment angle (β) of about 90°-120°.
19. Printing device according to claim 18, characterized in that a degree graduation (56) is applied to the end section (55) of the hollow shaft (30), which end section (55) projects from the impression roller (4), which degree graduation (56), via a fixed rotary-position marking (57), indicates the particular rotary position of the segment (54) with respect to the centre of the printing gap (6).
20. Printing device according to one of claims 1 to 19, characterized in that the conducting means (13) are thin wires which are insulated in highly resistive manner and are guided through radial bores (38) made in the hollow-cylindrical wall construction (12) of the impression roller (4).
EP83112742A 1982-12-27 1983-12-17 Printing device with additional electrostatic field Expired EP0114329B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83112742T ATE25035T1 (en) 1982-12-27 1983-12-17 PRINT UNIT WITH ELECTROSTATIC PRINT ASSISTANCE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH756782 1982-12-27
CH7567/82 1982-12-27

Publications (2)

Publication Number Publication Date
EP0114329A1 EP0114329A1 (en) 1984-08-01
EP0114329B1 true EP0114329B1 (en) 1987-01-21

Family

ID=4327175

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83112742A Expired EP0114329B1 (en) 1982-12-27 1983-12-17 Printing device with additional electrostatic field

Country Status (5)

Country Link
EP (1) EP0114329B1 (en)
JP (1) JPS59171653A (en)
AT (1) ATE25035T1 (en)
DE (1) DE3369280D1 (en)
FI (1) FI72929C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4401332A1 (en) * 1994-01-18 1995-07-20 Roland Man Druckmasch Method and device for filling depressions, such as cells or grooves, on the lateral surface of a rotating, cylindrical body

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1395339B1 (en) * 2009-04-10 2012-09-14 Ace Di Barbui Davide & Figli S R L ELECTROSTATIC ASSISTANCE EQUIPMENT FOR ROTOCALCO PRINTING, WITH PARTIALIZED LOADING OF THE PRESSOR.

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH607624A5 (en) * 1976-05-14 1978-09-29 Walter Spengler Printer with electrostatic printing ink transfer onto a dielectric substrate

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2084968A (en) * 1937-03-03 1937-06-22 Chapman Electric Neutralizer C Neutralizing apparatus
GB1293302A (en) * 1971-01-14 1972-10-18 Polygraph Leipzig Electrostatic impression cylinder
JPS54121809A (en) * 1978-03-08 1979-09-21 Hurletronaltair Inc Ink transfer assistant device
DE2810452A1 (en) * 1978-03-10 1979-09-13 Hurletronaltair Inc AC energised printer with resilient impression roller - has potential transmitted to web by reactive current through dielectric covering of roller

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH607624A5 (en) * 1976-05-14 1978-09-29 Walter Spengler Printer with electrostatic printing ink transfer onto a dielectric substrate

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4401332A1 (en) * 1994-01-18 1995-07-20 Roland Man Druckmasch Method and device for filling depressions, such as cells or grooves, on the lateral surface of a rotating, cylindrical body

Also Published As

Publication number Publication date
FI834694A (en) 1984-06-28
FI834694A0 (en) 1983-12-20
FI72929B (en) 1987-04-30
DE3369280D1 (en) 1987-02-26
JPS59171653A (en) 1984-09-28
FI72929C (en) 1987-08-10
JPH0377783B2 (en) 1991-12-11
ATE25035T1 (en) 1987-02-15
EP0114329A1 (en) 1984-08-01

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