The ornamental design for a ballpointpenhead, as shown and described.
FIG. 1 is a front perspective view of a ballpoint pen head showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left elevational view thereof;
FIG. 5 is a right elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is another perspective view thereof, with the ballpoint pen engaged.
The broken lines showing the inside of the bottom in FIG. 7 and the ballpoint pen in FIG. 8 are included for the purpose of showing portions that form no part of the claimed design.