Abstract: A device for preventing warping of double-faced corrugated cardboard sheets has a conveyance section for bringing a belt into contact with the upper surface of a single-faced corrugated cardboard sheet while moving the belt in a specified direction when manufacturing a double-faced corrugated cardboard sheet by gluing the single-faced corrugated cardboard sheet, which is obtained from a corrugated medium and a single facer side liner, to a double facer side liner; a heating section below the conveyance section for contacting the lower surface of the double facer side liner; multiple pressing units for applying pressing forces toward the heating section through the belt; and a control unit for controlling the pressing units so that the assignment of pressing forces in the width direction differs between the upstream side and the downstream side of the belt movement direction.

Abstract: A glue gun type gluing apparatus has glue guns 8a and 8b for applying glue to a gluing area in a joint flap 2 of a corrugated board sheet 1 for manufacturing a box, which runs on a box manufacturing line, a sheet end detection sensor 3 for detecting the front and rear ends of the corrugated board sheet 1, an encoder 7 for measuring the travel distance of the corrugated board sheet 1, and a control unit 9 for controlling the operation of the glue guns 8a and 8b. The control unit 9 learns and stores the position of gluing area on the basis of the information from the sheet end detection sensor 3 and the encoder 7 while the corrugated board sheet 1 is run at a low speed, and restricts the acquisition of detection signals by the sensor 3 during the time from the passing of the end point of the joint flap 2 to the arrival of the start point of the next joint flap 2.