The ornamental design for a deskblotter, as shown and described.
FIG. 1 is a perspective view of a desk blotter showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a front side elevational view thereof;
FIG. 4 is a rear side elevational view thereof;
FIG. 5 is a right side view thereof; and,
FIG. 6 is a left side view thereof.
The broken line showing of the remainder of the blotter is for environmental purposes only and forms no part of the claimed design. The three shaded regions reflect a contrast in color to their surrounding regions and no specific color is designated herein.