In many industrial applications there is the necessity to make materials such as decorated sheets of paper, plastic films, powders adhere on surfaces such as wooden panels, glass sheet, plates, without using adhesives. This is possible using electrostatic charge generators, charging bars, charging nozzles, electrostatic devices for in mould applications. An example of such applications is the use of charge generators within the pressing plant of noble panels. Or in the uniform distribution of lucite on glass sheets for the protection of the piling up. They are also used for the application of films on pre-painted plates. Or on packaging machines.