Coating apparatus – Solid applicator contacting work – With work-handling or work-supporting
Reexamination Certificate
1998-09-10
2001-03-06
Edwards, Laura (Department: 1734)
Coating apparatus
Solid applicator contacting work
With work-handling or work-supporting
C118S250000, C118S251000, C118S256000
Reexamination Certificate
active
06197113
ABSTRACT:
FIELD OF THE INVENTION
The invention is a device for the application of determinable quantities particularly of viscous liquids onto a movable substrate, consisting of an application roller that spans the length of the device, a supply mechanism to provide the liquid to the application roller, a contact press that pushes the application roller against the substrate, which, when pressed between the application roller and the substrate, creates a narrowing intake gusset in the direction of movement (D) of the application roller and at least one demarcation element that acts in combination with the application roller to define the width of application of the liquid (application width) being applied to the substrate.
DESCRIPTION OF RELATED ART
DE 295 17 095.6 describes a device with packing blocks that flank a tub containing the liquid (substance) on the frontal side and that are configured to slide along the long side of the device so that the width of application can be adjusted. The blocks consist of packing material, such as felt. By means of this packing material, the blocks make contact with a dispensing roller that forms the application roller as well as with a counterbalancing cylinder. This packing contact device must be configured in such a way that the liquid to be applied is held leak-free inside the holding tub, particularly while the device is stopped. A substance film forms on the counterbalancing cylinder; this film is applied to a foil on the vertex area of the counterbalancing cylinder. If the substance film being transported on the cylinder is relatively thick and/or the substance features a relatively high viscosity, a bulge-like thickening develops on the borders of the application width. Even if such thickening along the borders is low, for example amounting only to {fraction (1/100)} mm, a foil roll of several hundred layers would have a bothersome and unacceptable bulge. For relatively thick foil layers, the bulges on the edges would become so large that they would lead to application edges that are not clean or sharp; this, in turn, would lead to smearing and spreading of such impurities when the layering substance dries out partially or completely. Such an event, in turn, would make it more difficult to keep the device unclogged and operating smoothly. In order to significantly limit the layering edges that span the length of the foil, DE 295 17 095.6 provides for a scraper on the dispensing roller with a scraping blade such as a slat strip, and additionally limits the dispensing film edges by means of a stream of compressed air. Even such effort-consuming additional measures limit the coating thickness significantly. Additionally, regular scrapers with rolling scrapers or spread scrapers are known from WO 85/01226, for example.
SUMMARY OF THE INVENTION
It is the objective of this invention to improve the quality of application such that each application edge along the direction of movement of the substrate is created free of bulges and cleanly with precise edge demarcation, particularly in the fabrication of laminates, such as in the lacquering of foils.
This objective is achieved in a combination, where the demarcation element consists of a casing that covers the application roller along a section of the length of the roller and over a portion of its circumference with identical shape and diameter, while preserving its rotating capability, whereby the part of the section of the length of the roller forms a segment which is transverse to the direction of movement of the substrate, causing a liquid intake in that transverse direction. This invention shows that the intake section that stretches parallel to the application roller creates a hydrodynamically-induced cross current of substance in the area of the intake gusset. In this way, the substance is drawn along the borders into the liquid intake section in the longitudinal direction of the application roller, that means, perpendicular to the direction of rotation of the roller or cylinder. This cross current is so insignificant, when coordinated with the surface structure of the application roller (dispensing roller), that the application edge turns into a narrow, bulge-free run-off on the substrate, which is demarcated by an essentially straight line. With the cross flow section, a defined and cleanly delimited edge can be fabricated that remains free of layering, particularly on each long side of a foil roll piece, which can also be very narrow, because, as a result of the bulge-free run-off edge, edge impurities can be reliably avoided even on relatively thick coatings. By this invention, the demarcation casing can be easily attached to the application roller, whereby special measures that are conventionally designed for the packing contact system by means of a packing block on the application roller, a substrate and/or a counter device, will not be necessary. The dispensing, bulge-free application of substances achieved through this invention can be done directly onto a foil roll. Instead, the bulge-free application of substance to an application cylinder can also be provided for. Within the framework of this invention, the surfaces onto which the substance is applied are defined as substrates.
In the preferred configuration, the section of the application roller surrounded by the casing is open only where the roller touches the substrate. Thus, the casing appropriately surrounds about ⅔ to ⅘ of the application roller's circumference. Because the casing covers the largest portion of the circumference of the application roller, it was determined that not only is a clearly defined run-off edge guaranteed even if operation parameters are modified, but the casing can conveniently be positioned onto the application roller, which precludes its loss.
A particularly convenient configuration of the invention consists in arranging the application roller in a dipping tub that constitutes a supply mechanism, and to place the casing together with the application roller in the dipping tub, so that it can move perpendicular against the substrate surface.
It is particularly advantageous to place the dipping tub totally underneath the substrate. Particularly in relation with the aforementioned snap connection, where the application roller is exposed only in the area of the counterbalancing system, the circumference area of the application roller which dips into the substance contained in the dipping tub, including the area of its circumference that transports the substance upwards, is surrounded by the delimiting casing.
In a particularly preferred configuration, the device of this invention contains a magnetic contact press, whereby the substrate is placed on a magnetic beam and the application roller can be magnetically charged to press it against the substrate, and where the casing is permanently connected to the application roller. In combination with the magnetic press, the casing can be attached particularly easily. At the same time, it is made most usefully of a non-magnetizable material such as brass or something similar, so that it does not itself contribute to the pressing force but rather only moves along with the application roller, where the previously defined separate crosscurrent generates a precise run-off edge in a particularly easy and effective way.
In one configuration, the casing can be advantageously placed by means of a bearing which slides in a direction parallel to the pressing direction of the application roller.
In another advantageous configuration of the invention, the casing swivels least slightly around the axis of the application roller by means of the latter.
Subsidiary claims are oriented towards other effective as well as advantageous configurations of the invention, and particularly effective and advantageous implementation designs or possibilities for the invention are described in more detail in the following descriptions of the design examples illustrated in the schematic drawings.
REFERENCES:
patent: 4073263 (1978-02-01), Melton
patent: 4091129 (1978-05-0
Edwards Laura
Mattingly Stanger & Malur, P.C.
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