Question Regarding HP Printheads

[Alistair]

Hi all, I have lost magenta on my HP Z6200 printer. Nothing, not even one line on the test pattern so probably not a clog. No air in the line. This printer has two heads that share magenta and yellow. Yellow still prints perfectly. Is it possible for just one color in the head to die? How about one color in two heads? Seems unlikely. Anyone experienced this?

[Alistair]

Just for anyone reading this thread in the future, the answer is yes. One colour in the printhead can be completely blank and the other perfect. And no amount of cleaning will bring the blank colour back. Further, it can happen to both heads which print those two colours. I suspect what happened is that the colour (magenta) got air in the tube and fried both the magenta channel of both yellow/magenta heads because it was printing dry. Just a guess.

[kers]

thank you for sharing the experience...

I am about to weigh my heads and have a tool to refill them... if necessary.
Never done it before, so don't know how it will go, but heave enough semi-bad heads to try..
bought the tool in china for very cheap.

[Kyle Jackson]

Hi all, I have lost magenta on my HP Z6200 printer. Nothing, not even one line on the test pattern so probably not a clog. No air in the line. This printer has two heads that share magenta and yellow. Yellow still prints perfectly. Is it possible for just one color in the head to die? How about one color in two heads? Seems unlikely. Anyone experienced this?

Hi @Alistair, yes it happens.

First thing is weigh the heads. Looks like Z6200 heads are based on same common part as other DesignJets, so a full head should weigh 60 grams. Anything significantly less than that has air in it. Less than say 57 g should be purged. Around 45 g it's completely dry.

Also check the printhead error status codes on the front panel under info section (about 8 digits number). Check the codes in the service manual to confirm there are no printhead hardware errors.

If the head is good and just has air, it needs to be purged and refilled with ink. Draw any air from the printer tubes, and then use head priming tool to pull that ink into the printhead and pull the air out. I've posted about this in some recent threads. And LPS Computers has recently started carrying the head priming tools.

If all goes well the head should work okay again. Very important with HP discontinuing head production.

Cheers

[Alistair]

Hi @Alistair, yes it happens.

First thing is weigh the heads. Looks like Z6200 heads are based on same common part as other DesignJets, so a full head should weigh 60 grams. Anything significantly less than that has air in it. Less than say 57 g should be purged. Around 45 g it's completely dry.

Also check the printhead error status codes on the front panel under info section (about 8 digits number). Check the codes in the service manual to confirm there are no printhead hardware errors.

If the head is good and just has air, it needs to be purged and refilled with ink. Draw any air from the printer tubes, and then use head priming tool to pull that ink into the printhead and pull the air out. I've posted about this in some recent threads. And LPS Computers has recently started carrying the head priming tools.

If all goes well the head should work okay again. Very important with HP discontinuing head production.

Cheers

Thanks for the information Kyle, yes cessation of head production is very disappointing. When you refer to a head priming tool, are you referring to this tube priming tool or is there another to draw ink through the head?: https://www.lpscomputer.com/products/designjet-ink-tube-priming-tool?_pos=1&_sid=5087083e6&_ss=r

Many thanks

[Kyle Jackson]

Thanks for the information Kyle, yes cessation of head production is very disappointing. When you refer to a head priming tool, are you referring to this tube priming tool or is there another to draw ink through the head?: https://www.lpscomputer.com/products/designjet-ink-tube-priming-tool?_pos=1&_sid=5087083e6&_ss=r

So that pointy syringe is used to pull air/ink from the tubes in the printer itself. (I have 2 of these now so I can pull both colours for a printhead and re-use the ink without needing to clean the syringe between colours.)

The printhead priming kit is more like this one:
https://www.lpscomputer.com/products/updated-printhead-recovery-kit-for-hp-91-744-746-771-printheads-1?_pos=6&_sid=ee8e1f1bb&_ss=r
Ofc there are many others out there too. (IMO there's some unnecessary stuff in this particular kit, and I'm personally wary of putting any fluid other than ink thru a printhead for colour-critical use... I want to prime the head not wash it lol.) Anyhow the 3 key parts are: the funnel to pour the fresh ink into; the cap that goes over the printhead nozzles; and a blunt syringe that inserts into the cap to pull air/ink out thru the nozzles.

So in my use I confirm the printhead error codes don't indicate a hardware problem, I set the printhead up with the funnel and cap, then I pull some of each colour from the printer with the pointy syringe (pulling out any air at the same time), and put that ink into the correct side of the funnel. Repeat for the second colour. Then I use the blunt syringe on the printhead cap to pull air/ink thru the printhead nozzles. With some practice sort of develop a feel for how it's progressing, but checking the weight will confirm when it's full again.

I'm not a fan of LPS's video on this one (assuming it hasn't changed since I saw it last). They seem to pull only one colour, which means they're actually emptying the opposite side and filling it with air. Both colours needs to be pulled at once. And there needs to be enough ink in both sides so they don't bottom out and start sucking air. The ink tends to pull asymmetrically -- the level in each colour might be different, plus any different nozzle blockage effects, etc. So one colour might bottom out before the other moves much. Again practice helps but I tend to use 7 ml ish for each colour, and then draw slowly, and if one colour is about to bottom out and start sucking air, I top it up with a bit more ink. (Again 2 pointy syringes on hand are extremely handy here!)

Note this drawing ink from the printer is convenient but it kinda upsets the ink level tracking on cartridges, especially if they are low. You might have some run out earlier than indicated because of the ink you removed from them.

It's certainly not a convenient task, but in a world without more printheads it can keep us going. I topped up all the heads in my Z3100 and and its been okay since. I still have a couple of older heads I want to try this on to see if I can recover them.  (I accidentally primed another one before checking it's error code, so now it's a completely full but fried head  )

I think even more important is to periodically weigh the heads to know in advance they need priming before running them into real print issues and possible overheat failure. I wish I knew about that yearsss ago!

Cheers

[Alistair]

So that pointy syringe is used to pull air/ink from the tubes in the printer itself. (I have 2 of these now so I can pull both colours for a printhead and re-use the ink without needing to clean the syringe between colours.)

The printhead priming kit is more like this one:
https://www.lpscomputer.com/products/updated-printhead-recovery-kit-for-hp-91-744-746-771-printheads-1?_pos=6&_sid=ee8e1f1bb&_ss=r
Ofc there are many others out there too. (IMO there's some unnecessary stuff in this particular kit, and I'm personally wary of putting any fluid other than ink thru a printhead for colour-critical use... I want to prime the head not wash it lol.) Anyhow the 3 key parts are: the funnel to pour the fresh ink into; the cap that goes over the printhead nozzles; and a blunt syringe that inserts into the cap to pull air/ink out thru the nozzles.

So in my use I confirm the printhead error codes don't indicate a hardware problem, I set the printhead up with the funnel and cap, then I pull some of each colour from the printer with the pointy syringe (pulling out any air at the same time), and put that ink into the correct side of the funnel. Repeat for the second colour. Then I use the blunt syringe on the printhead cap to pull air/ink thru the printhead nozzles. With some practice sort of develop a feel for how it's progressing, but checking the weight will confirm when it's full again.

I'm not a fan of LPS's video on this one (assuming it hasn't changed since I saw it last). They seem to pull only one colour, which means they're actually emptying the opposite side and filling it with air. Both colours needs to be pulled at once. And there needs to be enough ink in both sides so they don't bottom out and start sucking air. The ink tends to pull asymmetrically -- the level in each colour might be different, plus any different nozzle blockage effects, etc. So one colour might bottom out before the other moves much. Again practice helps but I tend to use 7 ml ish for each colour, and then draw slowly, and if one colour is about to bottom out and start sucking air, I top it up with a bit more ink. (Again 2 pointy syringes on hand are extremely handy here!)

Note this drawing ink from the printer is convenient but it kinda upsets the ink level tracking on cartridges, especially if they are low. You might have some run out earlier than indicated because of the ink you removed from them.

It's certainly not a convenient task, but in a world without more printheads it can keep us going. I topped up all the heads in my Z3100 and and its been okay since. I still have a couple of older heads I want to try this on to see if I can recover them.  (I accidentally primed another one before checking it's error code, so now it's a completely full but fried head  )

I think even more important is to periodically weigh the heads to know in advance they need priming before running them into real print issues and possible overheat failure. I wish I knew about that yearsss ago!

Cheers

Great, thanks very much for the information Kyle!

[Kyle Jackson]

Good timing too, in another thread @kers just successfully rescued an "airhead". That's also where I originally posted info about weighing, error codes, and priming heads:
https://forum.luminous-landscape.com/index.php?topic=141083.msg1258667#msg1258667