HP Z6100 faint lines (banding)

[jonkovach]

Every once in a while, I will start to see faint lines building up and getting worse. They are going left/right across the paper, in the same direction that the carriage runs... so I can only assume that it's a printhead problem.

I clean them, run an alignment, and it fixes it temporarily, but they come back after some time of printing passes by.

I have done advanced printhead diagnostic prints... but they all look good. All are in warranty, and I really don't see anything wrong with them.

Any ideas on how to eliminate this?????

Thanks,
Jon

[SWCL]

Any pics?

Could be ink starvation maybe?


How do you clean the heads? - do you run the auto clean function or take them out? (forgive me if you can't do that with your model, i've only experience with a HP DJ5000 )

If its the same or similar to a 5000 then you may want to run the replace printhead function.. but just take the heads out, give them a gentle clean up - clean the electrical connections, pop them back in & then clean the capping stations or cleaner cartridges (again, not sure how the Z6100 differs?). Ours is the dye based model & it was suggested that we could use a little accetone (nail polish remover.. with accetone in) on a cloth to do the cleaning. - the cleaning stations are just cleaned with a damp cloth, or if they're really soiled.. flushed with some H2O & dried off.. always works for me

[jonkovach]

Yeah, I usually just do printhead cleaning from the front panel - and that only helps for some time.

Yesterday we took the printheads out and wiped them down and everything. They are just as easily accessible as the 5000/5500. That seems to have really helped out. If it comes back, I'll be sure to send some pics off - but that may have been the solution.

Thanks,
Jon

[SWCL]

If the heads are ever blocked you can put some accetone onto the cloth (lint free of corse) fold it into a pad & gently press the head onto the pad, leave it for 5/10 secs, then do the unthinkable.. wipe the head off the cloth - but only once & always in the same direction (so the front goes forward, not the sides).

Its like doing a head soak on a solvent printer.

If you use enough liquid on the pad & are gentle, you wont have any adverse effects.. at least we haven't & we do that fairly regularly.. when the calibration swatch idicates that it might need it.

[MacUser]

I had the exact same issue. No matter how many times I did a head cleaning it persisted. I changed all of the printheads and it persisted. Even though the image quality print didn't show any banding or lines missing. I even showed it to an HP certified tech (who was there to repair my 9000) and he was baffled. The only solution was to print in 16 pass. Obviously that slows down the printing time but, there is no more banding. And I can let things print over night if needed.

[jonkovach]

16 pass? Wowza.... how the heck do I get it to print in 16 pass mode? I have my printer profiled using Heavyweight Coated Paper (not HP), and the highest I can go is 10 pass mode.

[jens]

this is the problem with disposable printheads,
when you change the inkcartriges a lot there is getting air in the lines, then the printhead ( smal reservoir with ink ) uses up the ink inside and its not getting refilled enough because of the air. printhead runs out and you get the problem as mentioned above. compaire a new printhead with an used one, they will have a diffrence in weight.

So if you can refill the printhead reservoir it will work again

[jonkovach]

As far as I can tell, the changing of ink cartridges doesn't coincide with the appearance of the lines. How can I refill the printhead revervoir?

The only time I change cartridges is.... at night, before I print overnight, I will replace any low cartridges with full ones... then switch them back in the mornings. Then, obviously, when they run out I change them. Do you think this would have a negative impact on the quality of my prints?

[MacUser]

jonkovach Wrote:16 pass? Wowza.... how the heck do I get it to print in 16 pass mode? I have my printer profiled using Heavyweight Coated Paper (not HP), and the highest I can go is 10 pass mode.

I use Postershop. It has a 16 pass option. We also use GMG color profiling so we had to reprofile for 16 pass but, it prints nice.

[jonkovach]

I use Postershop as well, but on my media settings the highest pass rate that I can go is 10-pass. What media type are you using?
I am not familiar with GMG. I used to use ProfileMaker and am currently using Onyx Media Manager to create profiles. What is GMG?
Thanks,
Jon

[SWCL]

Just a guess - http://www.gmgcolor.com/english/home-of-color.html


Again, if the Z6100 isnt far different from the 5000.. cartridges & printheads are seperate entities.

It could be that when you change your cartridge air is getting into the ink line.. the air follows the flow of ink & ends up in the printhead. As air is lighter than ink it will rise to the top of the printhead. the air cant escape from the printhead as its not designed to, the jets are only open when the printer is printing.. when ink is going through which also stops the air escaping.

I think Jens is saying.. if you get enough air in the cartirdge you will get to the point where not enough ink is filling it & it is starting to print the air inside instead. - correct me if I'm wrong Jens.

leave the cartridges where they are, take the printheads out... and.. ? - half fill a syringe with ink.. hold the syringe so the ink is by the plunger, suck out the air.. invert the syringe.. fill with ink? not sure on that bit.


re: your passes, in MM do 'edit a media' not 'edit a mode' - under the basic media options step there is a button that says 'media options'. you need to be in varware mode - passes quality drop down.. select your passes. Mine only goes up to 12.. but that might be because it is ancient! - to save that setting, I find the safest way is to '>' next tab through the other pages using the previous calibrations etc. until you get to the finish screen.. if you hit the stop button & just save changes, you may find you have trouble when you come to print.

Might be worth making a copy of the media first (easiest to do in view media library screen) & working on that.

Bear in mind changing the number of passes may effect the colour of your outputs slightly.

[jens]

right on top SWCL thats what im trying to say!
( excuse me but english is not my basic language so its hard to explain it in english)
for more info PM me,

[Hotspur]

I have seen this many times and I would prepared to bet it is mild ink starvation as SWCL says right at the start - but I don't think it's in the printheads.

On the Z6100 there are valves which prevent any significant air intake. Even if air does get in there is a small air gap in the top of the head where the ink is pulled up & through by capilliary action. You can't fill a head with air in this way unless there is a technical problem with that head.

If this was the case you would have solved the issue by changing the offending head, which hasn't helped by the sound of it.

If you have ever used an Encad you will have seen this in action as you had to pull the air through the supply tubes manually with a syringe and then quickly attach the tube to the top of the printhead - you could then watch the ink disappear back up the pipe by several inches - how's that for air in the system!
Then you put some suction under the head itself & sucked the ink back up the tube until it dripped into the head - an air gap was essential in the head & it was maintained by the heads firing out ink & pulling more ink through by capilliary action.

Thus I think your starvation problem lies elsewhere - somewhere further back you may have a poor connection or a little hole or kink in an ink supply tube. This happens quite often & can result in an inky floor but more commonly ink starvation. If the system is allowed to rest for a while it will print OK and then the ink will bleed away gradually on the print. If you stop for a while it will be OK again before showing the same problem.

I would try printing a solid pure CMYKlclm colours to try to find the culprit - difficult if it's black of course as you have 3 to troubleshoot.

If the starvation is happening on more than one colour then it is unlikely to be a starvation problem with a cart / tube / printhead as the kink or loose joint would not affect the other feed systems.

In a 5000 / 5500 the entire tube network was accessible & user-replaceable & you could find a poor connection easily. Unfortunately the Z6100 is a very different beast and not as easy to access. Grab your screwdriver if you are brave or call HP if you are still in warranty.

The 5000/5500 does only go up to 12 passes max in any RIP - the Z6100 goes up to 16 in any RIP.
If you can't select it in Onyx it is because you have based your profile on an HP media type which doesn't support it.
There is a document produced by HP which Onyx had on their old website which listed which media types supported what pass rates.
Not sure where that doc now lives on the new site but it is a little out of date - more passes are now available than this document states due to recent improvements in the driver.

[Scott]

Hotspur Wrote:There is a document produced by HP which Onyx had on their old website which listed which media types supported what pass rates. Not sure where that doc now lives on the new site but it is a little out of date - more passes are now available than this document states due to recent improvements in the driver.

I believe this is what you're talking about...

z6100 Print Modes

[jonkovach]

Just an update... I've had the humidity up to 40-42% in the room, up from 30%, and the problem has not reappeared.
At this point, I believe that the humidity of the room was just too low.