Patent ID: 7222472

Claim:
A method of checking wrapping material in a packaging machine, comprising the steps of: causing the wrapping material to advance along a predetermined feed path; applying an accessory material to selected areas of the wrapping material; charging the wrapping material electrostatically as it passes through at least one first charging station, so that the electrostatic charges concentrate predominantly upon the accessory material, and across the remainder wrapping material, the distribution of the electrostatic charges has a lower and uniform concentration; subsequently verifying the distribution of the electrostatic charge on the wrapping material, as it passes through at least one second checking station comprising at least two sensors, by using the two sensors to sense a variation in concentration of the electrostatic charges and reveal a greater intensity electrostatic charge concentration on the accessory material and a lesser intensity electrostatic charge concentration on the remainder wrapping material; and comparing these two values.