Abstract: An improved drying system for drying coating fluids is provided by which conventional drying times are greatly reduced by subjecting the coating on a moving support web to a corona discharge in a manner creating a drying current flow along the length of the coating. Further reductions in drying time are realized by subjecting the coating to an intense electrostatic field, air streams and/or heat from a heated platen.

Abstract: A non-contact type registration system employing dipole-type electrostatic charges for precisely positioning insulative material to a selected location or workstation.

Abstract: An electrostatic coating method and apparatus are provided that are capable of applying an extremely thin and virtually constant thickness coating to a substrate, and includes a coating applicator having an opening formed of dielectric material through which coating material flows for coating purposes. The coating material supplied to the applicator is pressurized to maintain a substantially constant volume of coating material at the applicator opening output and is vibrated in the vicinity of the applicator opening to provide a uniform flow of coating material to the applicator output, to stabilize the shape of the coating material at the applicator output and to preclude changes in coating material flow rate caused by electrostatic field induced coating material dryout.

Abstract: A method and apparatus are provided for controlling the width and improving edge thickness uniformity of a layer of coating material electrostatically deposited on a moving web surface. The apparatus preferably includes a coating applicator, a rotatably mounted web-supporting backing roll spaced therefrom and a source of electrical power coupled between applicator and backing roll for generating a coating material charging and transporting electrostatic field capable of transporting the charged coating material from the applicator to a web surface as the web moves between applicator and backing roll for web coating purposes. The apparatus additionally includes a pair of electrodes coupled to a source of electrical power and mounted in an opposed relation on opposite sides of the charged coating material moving between the coating applicator and the web surface spaced therefrom.

Abstract: The maximum subcorona potential level to which a particular conductive bristle brush is able to regulate an electrostatic charge on charge-retaining material is substantially increased by limiting the electrical current available to said particular conductive bristle brush from a potential source coupled to said brush to a level that is less than a magnitude necessary for corona generation.

Abstract: A method and apparatus for electrostatically applying a layer of coating material to a moving substrate. In a preferred embodiment, a threaded shaft formed of dielectric material, having one end thereof coupled to a drive motor, has a portion of its threads mounted for rotation through a bath of coating material. An electrostatic field of predetermined magnitude is established between the coating material and a substrate surface spaced therefrom. The electrostatic field atomizes coating material accumulating on the ridge portion of the rotating thread and subsequently deposits a layer of the atomized coating material on the adjacent substrate surface as it is moved past the rotating dielectric thread at a predetermined angle with respect to the axis of rotation of the threaded shaft.

Abstract: A method and apparatus for establishing a uniform electrostatic charge of selected magnitude and polarity on a randomly charged web. The method and apparatus include first and second uniform electrostatic fields of predetermined magnitudes and of opposite polarities spaced from one another. Apparatus is provided for mechanically vibrating each electrostatic field at a particular magnitude and frequency while alternately passing the randomly charged web through each such electrostatic field at a particular angle with respect to the direction of field vibration to thereby establish a uniform magnitude and polarity electrostatic charge on the randomly charged web.

Abstract: Method and apparatus for establishing a uniform charge level on a randomly charged web having both positive and negative, bounded and/or free electrostatic charges. The method and apparatus include first and second uniform electrostatic fields of different magnitudes and of opposite polarities that are spaced from one another. Apparatus is provided for passing the randomly charged web through the first electrostatic field with a particular magnitude and polarity to either neutralize or change the polarity of either the positive or negative electrostatic web charges and then subsequently through the second electrostatic field with its different magnitude and its opposite polarity to either neutralize or change the polarity of the web charge present after exiting from the first electrostatic field to thereby adjust the electrostatic charge level to the desired uniform magnitude.

Abstract: Apparatus for improving the uniformity of a wet coating applied on a charge-retaining base material, said apparatus comprising charging means for producing an electric field between said coating and said base material while said coating remains in an essentially wet state.

Abstract: Excessive heat-generating current levels produced in semiconductive materials by electrostatically assisted coating apparatus employed to, for example, improve the uniformity of a coating applied to such materials are avoided by passing an auxiliary current through said semiconductive materials in the same region and in a direction opposite to that of the current produced by said electrostatically assisted coating apparatus such that the difference between the said current produced by said electrostatically assisted coating apparatus and the said auxiliary current is less than or equal to a predetermined value.

Abstract: An electrostatic field equal to or greater than a predetermined magnitude is established between the ends of a multiplicity of conductive bristles and a stationary conductive reference surface spaced from the end of the bristles for the puspose of rapidly arresting and/or preventing movement of insulative material having a portion thereof located in the electrostatic field established between the bristle ends and the reference surface and subsequently releasing the material by applying a voltage of opposite polarity to neutralize the force of the electrostatic field, arresting movement of the material.

Abstract: Method and apparatus for limiting unwanted vibration-induced variations in coating thickness of coating materials deposited on a moving web by an extrusion-type coating applicator employs a vibration generating electro-mechanical transducer coupled to the applicator that produces mechanical vibrations having an amplitude and frequency that produce a reduction in the magnitude of the vibrations causing the unwanted web coating thickness variations.

Abstract: Improved electrostatically assisted coating apparatus for placing an electrostatic dipole-type charge, of a predetermined magnitude, on material to be coated before and/or remote from the location where the coating is actually applied to said material by a coating applicator.

Abstract: A brush-like device having an array of conductive bristles is able to establish a relatively uniform dipole type electrostatic charge level on, for example, a moving web of charge-retaining material by passing said web through the relatively strong electrostatic field established by such a device when it is electrically connected to a relatively low potential DC source having the proper magnitude and polarity.

Abstract: A decrease in the ability of an electrostatic charge controlling brush to place a uniformly distributed charge on charge-retaining material is precluded by limiting the amount of current available to the brush to less than the magnitude necessary to melt the free ends or tips of bristles forming a portion of the brush to thereby avoid changes in bristle tip shape and the attendant reduction in ability to produce a particular electrostatic charge level that would result from such bristle melting.

Abstract: Apparatus including a brush-like device having an array of conductive filaments is able to neutralize electrostatic charges on, for example, a moving web of charge-retaining materials by passing said web through the alternating electrostatic field established by said device when it is electrically connected to a relatively low potential AC source having the proper magnitude and frequency.