The ornamental design for a portable labelprinter, as shown and described.
FIG. 1 is a first front top perspective view of a portable label printer showing our new design.
FIG. 2 is a second rear top perspective view thereof.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a top plan view thereof.
FIG. 6 is a bottom plan view thereof.
FIG. 7 is a right side elevation view thereof; and,
FIG. 8 is a left side elevation view thereof.
The dash-dash disclaim lines indicate disclaimed portions which form no part of the claimed design and the dashed-dot-dashed lines denote the boundary of the claimed design and form no part thereof.