JP2003527237A5 - - Google Patents

Claims (33)

An apparatus (10) for applying a liquid or paste-like application medium (16) to one or both sides of a moving base (U), disposed at a distance from the base (U), and applied to the application medium (16) A coating unit (12) that discharges the substrate (U) in the form of a free coating medium jet (18),
The substrate (U) is a material web (20) in the case of direct application, in particular a paper or paperboard web surface (20a), in the case of indirect application, a transfer element for transferring the application medium to the surface of the material web; In the apparatus which is preferably the surface of the transfer roll, the coating unit (12) is maintained at a _first predetermined potential (V ₁ ), and the base (U) is at least in the vicinity of the coating unit (12). maintained at a predetermined electric potential (V _E or V _2), the coating unit (12) from the substrate coating medium jet moves toward the (U) (18), to generate an electric field to apply a force to facilitate its movement An applicator characterized by that. The coating unit discharges the coating medium onto the substrate (U) as a coating medium curtain (18) moving from the coating unit (12) toward the substrate (U) under the action of gravity. The coating apparatus according to claim 1, wherein the coating apparatus is a coating unit. The coating unit is a free jet nozzle type coating unit that discharges a coating medium onto a substrate as a coating medium jet that moves from the coating unit toward the substrate substantially by a discharge momentum given from the coating unit. The coating apparatus according to claim 1. An electrode device (30) is provided on the upstream side of the coating unit (12) in the vicinity thereof, preferably away from the base material (U), and is maintained at a _third predetermined potential (V ₃ ). The coating apparatus according to any one of the preceding claims. An apparatus (10) for applying a liquid or paste-like application medium (16) to one or both sides of a moving base (U), disposed at a distance from the base (U), and applied to the application medium (16) A coating unit (12) that discharges the substrate (U) in the form of a free coating medium jet (18),
The substrate (U) is a material web (20) in the case of direct application, in particular a paper or paperboard web surface (20a), in the case of indirect application, a transfer element for transferring the application medium to the surface of the material web; In the apparatus which is preferably the surface of the transfer roll, the electrode device (30) is provided on the upstream side of the coating unit (12) in the vicinity thereof, preferably away from the base material (U), and a third predetermined potential ( V ₃ ), and generates an electric field that applies a force that promotes the movement of the coating medium jet (18) moving from the coating unit (12) toward the substrate (U). Coating device. 6. The coating according to claim 4, wherein the electrode device comprises at least one flat electrode, and the flat electrode preferably has a number of protrusions or needle points on the side facing the substrate. apparatus. 6. The electrode device (30), comprising a plurality of individual electrodes, preferably needle electrodes (32), arranged adjacent to each other in the transverse direction of the substrate (U). Coating device. An electric field is generated downstream of the point (P) where the coating medium (16) collides with the substrate, and the coating medium (16) applied to the substrate (U) is directed in the direction toward the substrate (U). Application device according to any one of the preceding claims, characterized in that another device (46) for applying force is provided. The further electric field generating device comprises another electrode device (46) located adjacent to the substrate (U) and preferably maintained at a _fourth predetermined potential (V ₄ ). Item 10. The coating apparatus according to Item 9. The first and / or third and / or fourth predetermined potentials (V ₁ , V ₃ , V ₄ ) have a value between about 5 kV and about 60 kV, preferably about 30 kV. The coating apparatus as described in any one of Claims. The coating apparatus according to claim 1, wherein the second predetermined potential (V ₂ ) is a ground potential (V _E ). In the case of direct application, it is a backing roll (22) that supports the material web (20) in the region of the application unit (12), and in the case of indirect application, the application medium is applied to the surface by the application unit. preferred backing element that is backing roll (22) is in contact with the electrode, the coating apparatus of claim 11, wherein the keep backing roll to a second predetermined potential (V _2). 13. The coating device according to claim 12, wherein the surface (22a) of the backing element (22) is in sliding contact with the electrode (50). 14. The coating apparatus according to claim 12, wherein the electrode contacts the bearing shaft (A) of the backing roll (22). 12. Direct application, the material web (20) is maintained at a _second predetermined potential (V2), for example by means of an electrode (48) formed as a web guiding element. The coating apparatus according to any one of 14. In addition to or instead of the electrode device (30) and / or the other electrode device (46), a magnetic field device is provided which influences the movement of the application medium (16). The coating device according to any one of the items. A device (34) for attenuating the air boundary layer (G) carried along with the base material (U) on the upstream side of the electrode device (30) along the moving direction (L) of the base material (U). The coating apparatus according to claim 1, wherein the coating apparatus is disposed. 18. The coating device according to claim 17, wherein the air boundary layer damping device comprises a suction device (34). 19. The coating apparatus according to claim 18, wherein a drooping scraper (36) in sliding contact with the substrate (U) is provided at a downstream end of the suction device (34). A further electrode device (40) is provided in the region of the air boundary layer damping device (34), preferably between the downstream end of the suction device (34) and the depending scraper (36). The coating apparatus according to any one of claims 17 to 19. 21. The coating device according to claim 20, wherein the further electrode device (40) comprises a plurality of individual electrodes, preferably needle electrodes, arranged adjacent to each other in the transverse direction of the substrate. 21. Application according to claim 20, characterized in that the further electrode device (40) comprises at least one flat electrode, the flat electrode having a number of protrusions or needle points on the side facing the substrate. apparatus. 23. The applicator device of any of claims 20-22, wherein the further electrode device (40) has a distance between about 2 mm and about 30 mm from the substrate. 24. A coating device according to any one of claims 20 to 23, wherein the potential of the further electrode device (40) is kept floating. 25. The further electrode device (40) is arranged in the air boundary layer damping device (34) and then electrically insulated (42). Coating device. The application unit (12) and / or the air boundary layer damping device (34) is maintained at a predetermined potential (V _E ), preferably at ground potential. Coating device. An apparatus (10) for applying a liquid or paste-like application medium (16) to one or both sides of a moving base (U), wherein the application medium (16) acts substantially on the base (U). It comprises a curtain-type application unit (12) that discharges as a curtain (18) or a veil that moves underneath, and the substrate (U) in the case of direct application is the surface (20a) of the material web (20), in particular paper or paperboard web. In the case of indirect application, a transfer element for transferring the application medium to the surface of the material web, preferably the surface of the transfer roll, and the side edge (18a) of the application medium curtain (18) In an apparatus provided with an edge guiding element (54) for guiding at least part of the movement between the substrate (U) and the substrate (U) under the action of gravity, at least one edge is provided. Guide elements (54) are coating apparatus characterized by having a roughened or toothed shaped surface (54a). The surface properties of the at least one edge guide element (54) are such that the wetting angle (a), which depends on the properties of the application medium (16) and the surface (54a) of the edge guide element (54), is less than 90 °. 28. The coating apparatus according to claim 27, which is selected. 29. An applicator device according to claim 27 or 28, characterized in that at least one edge guiding element (54) has an external thread. 30. The coating device according to claim 27, wherein the at least one edge guiding element (54) is made of glass or metal. 31. The coating device according to claim 27, wherein the at least one edge guiding element (54) is arranged to be displaceable in the transverse direction (Q) of the substrate (U). 32. The coating apparatus according to claim 27, wherein the angle formed by the edge guide element (54) with the vertical direction is adjustable. An electrode (56) extending preferably substantially parallel to the edge guide element (54) is provided in the vicinity of at least one of the edge guide elements (54), and is maintained at a predetermined potential (V ₅ ). 33. The coating apparatus according to any one of claims 27 to 32.