Olivetti d-Color MF451 Instructions Manual page 239

9.3 If print quality is deteriorated
5
Insert the print head glass cleaning tool into the print head
cleaning opening, pull it out, and then repeat this back-and-forth
movement two or three times.
6
Install the waste toner box.
7
Place back the print head glass cleaning tool to tray 1.
8
Close tray 1.
d-Color MF651/551/451
9
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