The ornamental design for a papertray on printer, as shown and described.
FIG. 1 is a perspective view of a paper tray on printer 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 side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view thereof.
The broken lines showing of portions of the paper tray on printer are for the purpose of illustrating environmental structure and form no part of the claimed design.