In YP11 automatic case filling and sealing machine,the defects occurred during gummed tape application,such as loose sealing and gummed tape edge curling,affected the normal running of equipments and product quality.A blower tester was then installed at the output end of gummed tape application station,and the conveyor for filled cases was relocated.After improving,the number of defective case reduced from 168 case/shift to 0,case appearance was improved,the labor intensity of operator was reduced,and equipments ran stably.