Exterior design for printer having duplex option

FIG. 1 is a top, front right side perspective view of an exterior design for printer having duplex option in accordance with my new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a front side view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.