OfficeJet Pro 6978 print quality declining

[SCGirl]

I have an HP OfficeJet Pro 6978 All-in-One printer and the print quality is declining. For example, if there is a blue block of color on a printout, the blue is very streaky. I have: unplugged, restarted, cleaned several several times, cleaned the printheads, smears, alignment, etc. and it's not getting any better. There are no error messages. I have installed a whole new set of cartridges today after chatting with HP online and it still isn't printing right. The Print Quality Diagnostic Page / Test Pattern 3 keeps on getting worse... the green bars fade into a yellow color and there are streaks all over it. I also received a message back in October about a possible cyan and yellow cartridge that could cause issues. Since then I have replaced the cartridges twice, so I do not think that is the issue. Please any help would be fantastic! I'm worried the printer is just on it's way out. 

[Kumar0307]

@SCGirl, Welcome to the HP Support Community!

This could be an issue with the printhead of the printer as you have already used 2 sets of ink cartridges.

Update the printer firmware

Click here to download and install the latest printer firmware from your MAC.

Click here to know different methods of updating printer firmware.

Refer to this document to resolve print quality issues - Black or Color Ink Not Printing, Other Print Quality Issues

And, yes, there was an issue with the Cyan and Yellow ink cartridges. Check if your printer qualifies for a replacement. Refer to -  'Incompatible' or 'Defective Cartridge' message

Hope this helps! Keep me posted. 

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