As I Understand the copy/scan quality isn't as good as the print quality is,
Don't worry as I'll be glad to help, however, to provide an accurate resolution, I need a few more details:
Have you attempted to clean the scanner glass?
Did you clean the ADF rollers?
While you respond to that, here's what you need to do:
Step 1: Clean the scanner
Fingerprints, smudges, dust, or debris on the scanner glass, under the scanner lid, or in the document feed slot can cause lines and color bands. Clean these parts with a soft, lint-free cloth sprayed with glass cleaner.
Step 2: Clean the ADF rollers
Dust or paper residue on the rollers or separator pad inside the automatic document feeder (ADF) can result in copy quality issues. Open the ADF, and then clean the ADF rollers and separator pad.
Step 3: Change the copy settings
Changing the copy settings, if available, might improve copy quality. Not all printers have the option to change copy quality settings, and some printers have more or less quality options. For specific steps, refer to the printer user guide on HP.com.
Step 4: Change the paper settings
Paper type and size in the input tray that do not match the paper type and size settings on the printer control panel can result in copy quality issues.