Abstract: In a laser scanning apparatus, in which a laser and a focusing lens are moved in a direction parallel to the cylinder axis during rotation of the cylinder so that the focused laser beam traces out a helical path on the cylindrical surface, the laser and focusing lens are mounted to permit relative movement in the said direction parallel to the cylinder axis and are separately driven, the driving means for the focusing lens being such as to permit a rate of movement of the focusing lens in the said direction more uniform than can be achieved with the laser driving means, the size of the lens aperture and the extent of the said relative movement during operation of the driving means being such that the laser beam always passes through the lens aperture; the uniformity of the movement of the focused laser beam along the cylindrical surface is then governed by the uniformity of the movement of the focusing lens, the lens head being lighter in weight than the laser head.