Hi wolfgangfromhildesheim,
If you've gone through the article that Allen provided, have gotten through to the step where you reset your printing system, and the issue persists, then the next step in the article is for you to contact the printer manufacturer for further assistance.
Check these things if you are unable to print, or if you see the message "No AirPrint Printers Found."
- Make sure your printer has paper, and enough ink or toner installed.
- Make sure your printer is connected to the same Wi-Fi network as your iOS device.
- Make sure your printer has power and is turned on. Try turning your printer off and then back on again to see if it resolves your issue.
- Check to see if your printer has any error lights or indicators displayed on the printer's control panel. Check the documentation that came with your printer to clear any errors displayed.
- Check with your printer's manufacturer to see if any firmware updates are available for your printer. Check your printer's documentation or contact the printer vendor for more information. A firmware update may be available, even if you just bought your printer.
About AirPrint - Apple Support
Take care,
Alex H.