Patent ID: 7151553

Claim:
An apparatus for applying reference markings to wallboard during a wallboard manufacturing process, comprising: (a) a horizontal element that traverses cover paper used to construct said wallboard, the horizontal element being located in between a cover paper source and a slurry source of the wallboard manufacturing process; (b) one or more printing devices attached to said horizontal element at a predetermined spacing so that the one or more printing devices form a substantially symmetric pattern of marks along the cover paper by ejecting marking material on the cover paper as the cover paper passes by the printing devices on the cover paper's way from the paper source to the slurry source; (c) one or more mounting brackets connecting said one or more printing devices to said horizontal element; and (d) at least one follower arm connected to said horizontal element and tangentially connected to the cover paper so that any horizontal shift in the cover paper equally shifts the follower arm which in turn equally shifts the horizontal element in order to keep the attached printing devices in horizontal alignment with the cover paper, as the cover paper passes by the printing devices to create the symmetric pattern.