Patent ID: 7938492

Claim:
A method of producing a toothbrush comprising: forming a head insert of polymeric material and having a thickness of between 1.5 millimeters and 3.0 millimeters, said head insert having a plurality of through holes; setting a plurality of bristles in said plurality of through holes of said head insert such that portions of said plurality of bristles protrude outwardly of a back surface of said head insert by 1 to 3 millimeters; fastening said plurality of bristles to said head insert by thermally welding the protruding portions to said head insert; placing said head insert with the fastened bristles into a cavity of a mold such that the fastened bristles are outward of the cavity of the mold; placing a plate-shaped pressure relief unit on said back surface of said head insert; and injecting a resin under pressure into said cavity of said mold so as to form a toothbrush body, said pressure relief unit placed so as to prevent the resin from being pushed outwardly from the fastened bristles by the injection pressure.