Toothbrush having needle-shaped bristle tapered at one end and manufacturing method thereof

Abstract

A toothbrush tufted with needle-shaped bristles. The bristles are formed of polyester resin. The bristles are 0.1 to 0.2 mm thick before tapering, 13 to 18 mm long, tapered 4 to 8 mm only on one end with a tapered tip thickness of 0.01 to 0.08 mm, and planted to be 7 to 13 mm high in the toothbrush.

What is claimed is:  
     
         1 . A toothbrush comprising: 
 needle-shaped bristles of polyester resin, which are 0.1 to 0.2 mm thick before tapering, 13 to 18 mm long, tapered 4 to 8 mm only on one end with a tapered tip thickness of 0.01 to 0.08 mm, and planted to be 7 to 13 mm high in the toothbrush.    
     
     
         2 . The toothbrush of  claim 1 , wherein the tapered tips of the needle-shaped bristles are 0.01 to 0.03 mm thick.  
     
     
         3 . The toothbrush of  claim 1 , wherein the tapered tips of the needle-shaped bristles are 0.03 to 0.08 mm thick.  
     
     
         4 . The toothbrush of  claim 1 , wherein part of the needle-shaped bristles are 0.01 to 0.03 mm thick in tip thickness and the other needle-shaped bristles are 0.03 to 0.08 mm thick in tip thickness.  
     
     
         5 . The toothbrush of  claim 1 , wherein the needle-shaped bristles are inserted in a head insert and thermally fused to be fixed to the head insert.  
     
     
         6 . The toothbrush of  claim 5 , wherein the head insert having the needle-shaped bristles is mounted in an opening of the head of the toothbrush and attached to the toothbrush head by ultrasonic bonding.  
     
     
         7 . The toothbrush of  claim 1 , wherein the needle-shaped bristles differ in length by 1 to 10 mm.  
     
     
         8 . A method of manufacturing a toothbrush having needle-shaped bristle tapered only on one end, comprising the steps of: 
 inserting non-tapered portions of the bristles into through holes of a head insert;    thermally fusing the non-tapered portions of the bristles protruding from the bottom of the head insert, thereby fixing the bristles to the head insert; and    attaching the bottom of the head insert to the head of the toothbrush.    
     
     
         9 . The method of  claim 8 , wherein the head insert is attached in an opening formed in the head of the toothbrush in the attaching step.  
     
     
         10 . The method of  claim 9 , wherein the head insert is attached in the opening by one of ultrasonic bonding and high frequency bonding.  
     
     
         11 . The method of  claim 8 , further comprising the step of adjusting the tip thickness of the bristles fixed in the head insert by cutting the tips of the bristles and grinding the cut tips.  
     
     
         12 . The method of  claim 8 , wherein the tapered tips of the bristles are 0.01 to 0.08 mm thick.  
     
     
         13 . The method of  claim 12 , wherein the tapered tips of the bristles are 0.01 to 0.03 mm thick.  
     
     
         14 . The method of  claim 12 , wherein the tapered tips of the bristles are 0.03 to 0.08 mm thick.  
     
     
         15 . A method of manufacturing a toothbrush having needle-shaped bristle tapered only on one end, comprising the steps of: 
 inserting non-tapered portions of the bristles into through holes of a head insert;    thermally fusing the non-tapered portions of the bristles protruding from the bottom of the head insert, thereby fixing the bristles to the head insert;    attaching the bottom of the head insert to an upper metal mold;    combining the upper metal mold with a lower metal mold; and    injecting resin into the lower metal mold through an inlet, thereby attaching the head insert to the head of the toothbrush.    
     
     
         16 . A method of manufacturing a toothbrush having needle-shaped bristle tapered only on one end, comprising the steps of: 
 inserting non-tapered portions of the bristles into through holes of a lower metal mold to protrude 2 to 5 mm from the lower metal mold;    thermally fusing the protrusions;    combining an upper metal mold with the lower metal mold; and    injecting resin into the upper and lower metal molds, thereby fixing the bristles directly to the head of the toothbrush.