HP 815MFP - Manual (Page 30)

24 hp designjet 815mfp & scanner 4200
how do I maintain/recover my system?
maintenance procedures
Maintenance procedures should all be performed in a single
maintenance session, starting with Cleaning the scan area and
ending with Camera alignment and calibration.
The scanner maintenance procedure should be performed once per
month.
cleaning the scan area
1. Turn the scanner power off.
2. Disconnect the scanner power cable.
3. Open the scanner cover.
Place your fingers just inside the insertion slot and flip the cover
upwards to expose the scan area.
4. Remove the pressure platen.