APPARAT FOR ATT ASTADKOMMA EN LIKFORMIG LADDNING PA EN YTA AV ETT LEDANDE UNDERLAG

摘要

An apparatus for providing a uniform charge upon a surface of a conductive base, the apparatus includes a longitudinally elongated corona discharge element, a potential source connected to the discharge element for applying a corona generating potential, conveyor means for conveying at least one conductive base along a path in a direction along the length of the discharge element and a protective grid assembly disposed directly adjacent the discharge element. The grid assembly includes protective elements having sufficient resistance to prevent the conveyed base from contacting the discharge element and to case a persistent electrical shadow on the conveyed base. The protective elements are skewed longitudinally of the discharge element and relative to the direction of the conveyed base whereby the electrical shadow cast by the protective element is equally distributed over the conveyed base.