Officejet 6700 Black wont print

[PlanetRambler]

I bought this printer from a neighbor to use for school. They said it hasn't  been used in some time and there were empty CM&Y cartridges in it. But the carriage moved and the display worked, so they almost gave it to me knowing I'm a student on a budget. I dl'ed the driver from HP, the wifi seemed to work so I got Scan to work fine.
 
When I rec'd a $50 combo pack of 10 cartridges from Amazon, the CM&Y units popped in fine but none of the 4 black cartridges seated correctly, as if the spring were broken (it isn't), so the cartridge doesn't pop in and out with a gentle push. I tried every which way of jiggling them, restarting, etc. but the display would show only missing ink/cant proceed errors. The contacts look shiny.



So I drove to Target and got an HP black cartridge to see if that made a difference. It seated only slightly better but I finessed it so it stayed in place and it kicked into 10 minutes of whirring, until finally I was able to try a test print.

Supply levels show all inks full, although it calls out non HP in CM&Y cassettes. I didn't realize that might be a problem but those colors print so I don't think buying HP CM&Y inks is the solution. 

I did all utility, sample, diagnostic, alignment and test printouts from the device display and the HP utility app but no black ink prints, no text so nothing to diagnose and the color is washed out. 
 
I searched this forum, found only one real thing to try - "For a dried ink problem, run Clean Printheads over next 2 days, maybe new ink will dissolve old. If not, new printer"

Helpful suggestions appreciated

[TEJ1602]

@PlanetRambler, Welcome to HP Support Community!
 

If you have already performed the steps from the document Color or Black Ink is Not Printing and the issue persists, it could be a hardware failure.

Please reach out to HP Support in your region regarding the service options for your printer.

Hope this helps!

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