[NeoStarO1]

Investigating on docs post this here is what I found.

HP All-in-One and Fax Products - Cleaning the HP All-in-One or Fax

Here is a quote of interst related to docs post if its a scanning problem as versas a printing problem.

Quote:

Scanner glass and white scan backing
If you have any of the following symptoms, the scanner glass or white backing may need cleaning:

Black spots or lines appear in copies and/or faxes.
"Replace scanner cover" error message on the front panel display.
Special copy features such as clone do not work correctly
The scanner glass position and size will depend on the product.

Scroll-fed products have a narrow glass strip located under the front panel (see Figure 1) or under the scanner cover (see Figure 2).
Flatbed products have a large scanner glass under the top cover.

Might be worth checking it out.