PRINTED MEDIUM EXPANSION/CONTRACTION QUANTITY COMPUTATION METHOD AND PRINTED MEDIUM EXPANSION/CONTRACTION QUANTITY COMPUTATION DEVICE

摘要

To provide a printed medium expansion/contraction quantity computation method and a printed medium expansion/contraction quantity computation device that can easily compute a quantity of expansion or contraction of a printed medium if the printed medium has printing expansion or printing contraction in a latter stage when overprinting is performed by a roll-to-roll type screen printer.SOLUTION: In a first stage, a plurality of first alignment marks 102 are arrayed and printed in a conveyance direction of a continuous form 100 in printing of a former stage together with a first printing pattern of the former stage. In a second stage, a plurality of second alignment marks 106 are arrayed and printed in the conveyance direction of the continuous form 100 in printing of a latter stage together with a second printing pattern 111 of the latter stage. In a third stage, an image of both the alignment marks 102, 106 on the continuous form 100 are picked up by a camera 45. In a fourth stage, a shift quantity between the first alignment mark 102 and the second alignment mark 106 which correspond to each other in the conveyance direction is computed as an expansion/contraction quantity on the basis of the picked-up image.SELECTED DRAWING: Figure 6