The ornamental design for an exposureunit for lithographicplates, substantially as shown and described.
FIG. 1 is a front elevational view of an exposure unit for lithographic
plates showing my new design, the rear being a mirror image but without
the control panel;
FIG. 2 is a top plan view thereof;
FIG. 3 is a right side elevational view thereof, the left side being a
mirror image but without the electrical cord;