The ornamental design for an ozonegenerator, as shown and described.
FIG. 1 is a top perspective view of an ozone generator showing my new design;
FIG. 2 is a left side view of the ozone generator shown in FIG. 1;
FIG. 3 is a front view of the ozone generator shown in FIG. 1;
FIG. 4 is a right side view of the ozone generator shown in FIG. 1;
FIG. 5 is a rear view of the ozone generator shown in FIG. 1;
FIG. 6 is a top view of the ozone generator shown in FIG. 1; and,
FIG. 7 is a bottom view of the ozone generator shown in FIG. 1.
The broken lines shown in the figure drawings are included for the purpose of illustrating environmental structure and form no part of the claimed design.