Printhead substitution

[hriosm]

Hi,

My plotter DJ T795 was working fine but then started to fail yellow. Stopped printing and after a week gave it another try. Turned on, spent more than 15 min cleaningand told me to substitute printhead. Cleaned contacts on printhead and carriage and installed another functioning printhead borrowed from another plotter. Entered printhead susbtitution selection and tells me the printhead substitution has not been completed right away as if not recognized it was another printhead. 

How do I reset this "prinhead substitution" cycle so it checks for new printhead?

Another alternative?

Regards

[D Hook]

Do you have any low ink levels in any cartridges?  If the printer detects low ink levels it won't complete the printhead replacement.  That's been my experience anyway.

[hriosm]

Hi D Hook,

The lowest level cartridge is around 30%, enough to complete a cleaning cycle. Talked to HP Support and they say all cartridges must be at least 40%, no matter if your cartridge is 69ml or 130ml. Still don´t have new cartridges to try it. 

What make me furious is that HP is clearly twisting the firmware to force users to buy more HP supplies.

If firmware could tell me first hand you will not be able to substitute because you have lower than 40% ink instead of letting me go into a >15 min cleaning cycle wasting ink, would be preferable .

[D Hook]

While I'm not defending HP and their firmware choices, there is some bit of logic in their need to have the cartridges at 40% or more.  Some of their printers automatically do a Printhead alignment after replacing printheads and I believe your is one of them.  To be sure the alignment gets completed they write the firmware to check the ink levels before starting the alignment.  

I have no evidence to back this up; only my own experience of frustratingly trying to trouble shoot what I thought was a mechanical problem but was actually a low-ink problem.  What troubled me was that this little tidbit of info was no where to be found in the owners manual or the service manual.  It might be there but I must've missed it.  But since then I've learned to keep all ink supplies above 50% to rule out this possiblility when trouble shooting.  Hopefully, if someone has more insight they'll chime in.

Let us know the result when you get the new ink installed.

[hriosm · Accepted solution]

Borrowed the cartridges and the same time read this article:

Printhead Replacement Incomplete on Designjet T and Z Printers (lpscomputer.com)

Yes, 40% is needed.

15 min of wasting more ink and told me to change printhead. Changed  printhead and other 20 min wasting ink did it !

Thanks!