Abstract: In an apparatus for applying ink patterns on oriented strand boards, the boards are serially moved closely adjacent to and past ink jets, and ink is deposited on the boards. To deposit the ink accurately on the boards they are advanced by pinch and drive rollers which also ensure that the boards are flat as they move past the jets. Detectors are used to detect boards which cannot be flattened or are irregular in shape and in such a case the ink jets are moved to avoid impact by an irregular board. During printing, the panels and the ink jets are about 0.0625 inches to about 0.125 inches apart, and the panels are moved at a rate of about 150 ft/minute to 600 ft/minute.