Why is the print quality of my LabelWriter 450 not good?

There are three possible solutions to the problem at hand.

there’s third-party labels

Labels that are not made by DYMO may not work with your LabelWriter. 3rd party labels may have different thermal sensitivity than DYMO labels, and the perforated holes on 3rd party labels may not be recognizable by the device. Make sure your labels are genuine DYMO LabelWriter brand labels.

Dirty print heads

To clean the print head, first remove the label roll by lifting the lid and pressing the black-and-white eject button on the right-hand side of the device. Clean the print head and the bottom of the label roll with a small, soft brush or cotton swab.

and old or defective labels

It is also possible that the label roll in the device is old, or has become defective. To check for a defective roll, insert a different roll from a new box. If the new roll produces a print with no problems, it means that the old roll was old or defective.