Method of forming score lines on blank, method of manufacturing package using same, and package

Abstract

A blank forming step for forming a sheet-shaped resin blank able to be formed into a box by folding and bending, and a score line forming step of forming score lines in score line forming areas of the blank which are to be bent to form outer edges of the box, to extend in the direction in which the outer edges should extend. In the score line forming step, the score lines are formed in a manner causing grooves to be produced on the back side of each score line forming area, along the score lines, through plastic deformation. The blank therefore does not undergo tensile stress pulling on the blank to either side of each groove, and thus, does not undergo warping as a whole. The blank thus retains its sheet shape and can be steadily supplied to a packaging machine.

1 . A method of forming score lines on a blank, comprising steps of:
 forming a sheet-shaped resin blank able to be formed into a box by folding, and   forming score lines in score line forming areas of said blank which are to be bent to form outer edges of the box, to extend in a direction in which the outer edges should extend, wherein in said score line forming step, said score lines are formed in a manner causing grooves to be produced on a back side of each score line forming area, parallel to said score lines, through plastic deformation.   
     
     
         2 . The method according to  claim 1 , wherein the grooves are formed along the respective score lines in a manner corresponding to the respective score lines. 
     
     
         3 . The method according to  claim 1 , wherein
 the box to be formed comprises a box-shaped container open at the top and a box-shaped lid connected to a top edge of the container functioning as a hinge to open and close the container,   said blank comprises a main section for forming the container, extending in one direction, and a sub-section for forming the lid, connected to an edge of the main section which is to form the hinge,   the main section includes a front main panel, a bottom panel and a rear main panel for forming a front wall, a bottom wall and a rear wall of the container, aligned in the direction and delimited by transverse fold lines, and outer and inner side main flaps for forming an outer and an inner layer of each side wall of the container, connected to either side of the front main panel and of the rear main panel,   the sub-section includes a rear sub-panel, a top panel and a front sub-panel for forming a rear wall, a top wall and a front wall of the lid, aligned in the direction and delimited by transverse fold lines, and inner and outer side sub-flaps for forming an inner and an outer layer of each side wall of the lid, connected to either side of the rear sub-panel and of the front sub-panel, and   said score line forming areas are provided between the front main panel and the outer side main flap, between the rear main panel and the inner side main flap, between the rear sub-panel and the inner side sub-flap, and between the front sub-panel and the outer side sub-flap, respectively.   
     
     
         4 . The method according to  claim 1 , wherein in said blank forming step, a printed layer for providing information about items to be contained in the box in a manner recognizable from the score line forming area side is formed on a side of said blank opposite to said score line forming area side. 
     
     
         5 . The method according to  claim 1 , wherein said blank is made of polyethylene terephthalate. 
     
     
         6 . A method of manufacturing a package using the score line forming method according to  claim 1 , wherein after said score line forming step, said blank is formed into the box by folding and bending said blank with the score-lined surface outside. 
     
     
         7 . A package with rounded edges manufactured by the package manufacturing method according to  claim 5 .