HP officejet 8500a paper jam

[Gimell]

Hello dear forum members and specialists,

i've encountered an issue that I couldn't find on the forum. My printer HP officejet 8500a is displaying a paper jam error:

It takes the paper up to the rollers just before printing (but doesn't print), gives an error, and asks to press okay after resolving. If I press okay, the sheet continues without jamming, and subsequent sheets start printing.

I've found that the white coupling gear is broken, as usual, near the bolt of this gear (at the thinnest part of the gear). I printed a new one on a 3D printer and installed it, generously lubricating it with gear grease (the issue shouldn't be related to grease), as I saw that people fixed it by simply spraying WD40.

After assembly, the error persists following the same pattern: Takes a sheet Reaches the printing platform Doesn't start printing Displays a paper jam error After pressing "okay," a clean sheet continues to the output, and subsequent sheets start printing.

Before disassembling the printer, I hadn't seen that the coupling gear was broken. I completely removed and cleaned the service station from remnants of old jammed paper and ink that had leaked onto the table due to overflow. I assumed the issue was related to this, but it didn't resolve anything.

I want to resolve this issue due to constant realignments caused by this error. After several attempts, I've already used up 2 ink cartridges.

Thank you in advance for your responses;

I would greatly appreciate guidance in solving my problem.

Best regards!