METHOD AND APPARATUS FOR SENSING AND CONFIRMING COATING ADHESIVE OF AUTOMATIC BOX MAKER

PURPOSE:To sense and confirm coating of adhesive by sensing a difference of output balance when the adhesive passes through only one electric field. CONSTITUTION:A hot electrode 4 outputs a change in permittivity by a positive signal and applies an electric field to a passing position of coating adhesive B. A hot electrode 5 outputs by a negative signal and applies an electric field to a non-passed position of the adhesive B. When an automatic box maker 1 is operated, a paper box material S coated with the adhesive B passes, a material A shields both electrodes to vary permittivity of a high frequency wave in response to water content of a material A. The varied permittivity equally affects the positive and negative signals so that an output balance of both remains balanced. Then, when the adhesive B is applied to the electric field of the electrode 4, it is affected by water content of the adhesive B, only a signal output of the positive side is changed, and a balance of the outputs is lost. This unbalance is sensed by a sensor 6, a controller 7 confirms that the adhesive B is correctly coated.