Patent ID: 7238394

Claim:
A powder coating apparatus for electrostatically coating a surface of an electrically grounded, said apparatus comprising: a gun main body for spraying powder coating material toward said object to be coated; at least one corona electrode arranged at a tip end of said gun main body for charging the powder coating material thus sprayed; a pulse signal generation circuit for generating a pulse signal having a pulse width and a pulse interval of 5 milliseconds to 500 milliseconds; an oscillation circuit for converting the pulse signal generated from said pulse signal generation circuit into an oscillating signal; a booster circuit for boosting a voltage of the oscillating signal converted by said oscillation circuit; and a rectifier circuit for rectifying the oscillating signal boosted by said booster circuit to form a pulse-shaped discharge signal having a pulse width and a pulse interval of 5 milliseconds to 500 milliseconds; wherein the pulse-shaped discharge signal can be impressed upon said corona electrode to generate a corona discharge.