Filling print heads

When exactly, does the printer top off the print heads so they don't get low on ink when printing solid colors? Is there a sensor in the PH that tells the printer it's low on ink and the printer sends more ink via the attached ink tube? I have issues with the Lc/Lm PH getting starved for ink. When I take out the PH and weigh it, it comes in at 47g. A new Lc/Lm PH is 63g as are the other colors. When I take out another head, say, C/K it weighs 63g. And the optimizer PH weighs 63g. There is no air in the Lc/Lm line because I purged it with a syringe. I've also done a manual PRIME and it still remains @ 47g. This is a new head and I get no other errors about the head. The carriage board checks out OK. The air pressure system checks out OK. There is not much else in the ink system to check. It's just not filling the head.

Hi @digicomimaginginc@gmail.com,

Can you please advise the printer model you are using?

HP 365

Hi @digicomimaginginc@gmail.com,

If the PHs weight is 47g it is because there is some air in the ink tubes.

After the purge, you have to replace the affected PH. You cant recover a starved PH.

I hope this helps.

Yep, found that out. Replaced with a new PH and problem is resolved. The lesson learned here is DON'T run with expired inks. There is some separation of carrier/pigment which apparently caused some air in the line due to viscosity difference. And you are correct; any attempt at trying to get a PH to refill outside of the normal parameters of the printer will fail. It's a fine tuned system HP has, so best to keep everything within specs.

Also, something to keep in mind. If you run with expired inks and put in a new PH, it will immediately void the warranty on the PH. So if that print head fails before it reaches 1000ml, you will not be able to get a replacement @ N/C.