A method of printing adhesive lines on a narrow and flexible ribbon-type material, whereby the adhesive lines are linearly spaced and applied transversely to both sides of the ribbon at the same time; and the relationship of the lines on the obverse side to the lines on the reverse side are staggered, with each side maintaining equal spaces between the lines. The preferred apparatus for performing the method of two-sided simultaneously printing is a rotogravure offset method which includes two rotogravure rolls and two rubber rolls, with each rubber roll resting on each rotogravure roll in pyramid fashion, whereby the two rubber rolls simultaneously make an impression on the ribbon material moving between them as they rotate. Downstream from the printing station, a bar, having blades mounted on each end, rotates and strikes the printed ribbon against a cutting anvil; this only partially cuts the ribbon, so that it maintains its continuity; and as it fan-folds, the adhesive lines mate exactly, line on line, from the same side of the ribbon, and it descends to a flat-folded position between guide pins on a horizontal press-bar. After the desired number of ribbon folds is reached, another press-bar is placed on top of the folded ribbon and heat is applied; and later, the bonded plies are expanded, forming honeycomb.