The latest Windows Update (March 2021), KB5000802, causes problems when printing images on thermal photo printers. Specifically, only part of the image is printed as a strip on the paper. The rest of the page remains blank.
If you encounter this issue, you can resolve it by uninstalling the update. You can find instructions on how to do this, for example, at the following link: https://www.heise.de/tipps-tricks/Windows-10-Update-deinstallieren-3982288.html. Afterward, you should make sure that no automatic updates are installed for the time being. You can find instructions on how to do this, for example, at the following link: https://www.heise.de/tipps-tricks/Windows-10-Automatische-Updates-deaktivieren-3971647.html.
If you are not (yet) experiencing this error, the faulty update has apparently not been installed yet. In this case, you should ensure that it stays that way and temporarily disable automatic updates, as described in the second of the two links mentioned above.
Microsoft is already working on a solution to this problem. We will keep you informed here as soon as the issue is resolved and you can re-enable automatic updates.