Method and apparatus for the electrostatic charging of a web or film
First Claim
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1. A method for electrostatically charging a web or film having first and second sides, the method comprising:
- inducing a positive charge adjacent the first side of said web or film, and a negative charge adjacent the second side of said web or film; and
inducing a negative charge adjacent the first side of said web or film, and a positive charge adjacent the second side of said web or film;
and further comprising sequentially inducing a plurality of timesa) a charge adjacent the first side of said web or film, wherein the charge after inducing is substantially opposite the charge adjacent the first side of said web or film immediately prior to inducing, andb) a charge adjacent the second side of said web or film wherein the charge after inducing is substantially opposite the charge adjacent the second side of said web or film immediately prior to inducing.
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Abstract
Method and apparatus for electrostatically charging a web or film by subjecting the web or film to an electric field generated between a single bar or wire electrode and the curved surface of a second electrode, and optionally sequentially subjecting the web or film to subsequent electric fields preferably in which the polarity of the field, relative to the web or film, is reversed.
249 Citations
50 Claims
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1. A method for electrostatically charging a web or film having first and second sides, the method comprising:
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inducing a positive charge adjacent the first side of said web or film, and a negative charge adjacent the second side of said web or film; and inducing a negative charge adjacent the first side of said web or film, and a positive charge adjacent the second side of said web or film; and further comprising sequentially inducing a plurality of times a) a charge adjacent the first side of said web or film, wherein the charge after inducing is substantially opposite the charge adjacent the first side of said web or film immediately prior to inducing, and b) a charge adjacent the second side of said web or film wherein the charge after inducing is substantially opposite the charge adjacent the second side of said web or film immediately prior to inducing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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- 9. A method of electrostatically charging a web or film which method comprises generating a dispersed non-arcing electric field between an electrode means having an electrically conductive curved surface and a single conductive bar or wire spaced from said curved surface, and passing the web or film through and subjecting it to the dispersed non-arcing electric field between said bar or wire and said curved surface.
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38. The method of 37 wherein the polyolefin is a polypropylene.
Specification