Patent ID: 7330203

Claim:
An offset printing unit comprising: an offset printing plate received on a rotatable cylinder; and at least one device for imaging the printing plate movable with respect to the printing plate essentially parallel to an axis of symmetry of the cylinder, the device including an array of n laser diodes which image n image points from the moving device onto the rotating cylinder, so that one laser diode of the array is allocated to each i-th point, with i being from {1, . . . , n}, encircling the axis of the cylinder on a helical path, the n image points being separated by a spatial interval l between adjacent image points, with a pitch distance p of dots to be imaged by the array, the laser diodes being individually-drivable single stripe laser diodes; the spatial interval l between adjacent image points, measured in units of the pitch distance p of the dots, being an integral multiple m of the pitch distance p between the dots; wherein the integral multiple m and the number n of image points have no common divisor.