Z3200 Blocked Nozzles - Forlorn Hope

[William Chitham]

I am printing an exhibition of landscapes on Hahne Photo Rag and most of them have very neutral gray skys with fairly subtle cloud formations and I am getting chronic "micro" banding. Through a glass it looks as though the areas of banding are pretty much covered by a single ink, usually light gray, and if there is even a single dropped nozzle in the head it is visible. I have tried printhead cleaning, paper advance calibration, forced drop detection reset, cleaned the capping station but I cannot get a perfect nozzle check and I cannot eliminate the banding - even after replacing all the black & gray printheads. Any ideas anyone?

Thanks,

William Chitham.

[John Nollendorfs]

I've heard some printers will exhibit this microbanding in normal print mode. Have you tried a better print mode? When I had print heads that were nearing end of life, this would happen in normal print mode. It's worth a try, just takes twice as long to print out!

[namartinnz]

I'd try a finer mode too, I never print in normal mode if that's what you've been doing, either fine or ultra fine. It may be another of the gray heads playing up?

[William Chitham]

All the gray and black heads are brand new, printing in finest mode. The frustrating thing is that the very first thing I printed after installing new heads was a nozzle check and there were a few blocked nozzles straight out of the box. My only theory is that they are being contaminated by the squeegees that are supposed to clean them at the service station, perhaps I need to strip that down and clean it or even replace it.

Over 10 years or so of HP Z ownership I've never found the printhead cleaning to be at all effective. Nozzles come and go a bit as a result of use or the printer's self maintenance but I don't remember ever having any success running the head clean.

Taking a day off today, back at it tomorrow. If the nozzle fairies haven't magically done the business by then I suppose it's add noise time.

William.

[Mark Lindquist]

Could be the PCA board.  Try replacing that.

[kers]

Hello Wiiliam,
Did you calibrate the paper advance?
and after that align the printheads?
-

[deanwork]

It is not true that doing a head cleaning procedure has no effect. In 8 years I've only had micro banding twice with good heads and both times were immediately fixed with a simple head cleaning. These times occured after printing hundreds of large prints in a row on cotton matte rag. That was very rare.

If your capping station and waste tank are mucked up that can cause this. I would start to do the head replacement procedure where the head unit comes out, then turn off the printer and unplug it. Get a nice work light and a roll of paper towels and clean off the cap station area where the head rests and thoroughly clean that area and wiper blade. If your spittoon, the wast tank, is totally full, which takes a LONG time but eventually will occur, then you either need to remove the printer cover and clean all that out, Or better yet just replace it for another 5 years or so of printing.

I do hope you keep this printer plugged in at all times. If you don't you will have problems for sure. This is the best system for monitoring the head condition of any printer I've ever used or heard of. But if it is not used for a long period of time and is turned off you could have some dried in the lines that only cleaning can clear.

Hello Wiiliam,
Did you calibrate the paper advance?
and after that align the printheads?
-

[William Chitham]

Thanks for the all suggestions. As I said in the original post I replaced all the heads and ran through all the alignment and advance calibrations. I don't think the PCA is at fault, if that was causing nozzles not to fire I'd expect the same ones to be out after replacement which wasn't the case. The printer is switched on all the time and used nearly every day.

I have now conquered the banding for the time being and am producing acceptable prints. After much inspection with a loupe under various different lighting conditions I came to the conclusion there were two different types of banding occurring.

Firstly faint dark lines caused by incorrect paper advance (despite having been calibrated and producing a good looking plot in the service diagnostic images). Manually adjusting the paper advance +4% cured this.

Secondly the fine lines left by a individual dropped nozzles. I still can't get a perfect nozzle check, despite replacing all the heads as I said, and I have yet to have any success with the head cleaning routine. I have cleaned the capping area and even had a poke about under the cover where the head wiping squeegees are scraped off but I still think this is the only possible place the nozzles could pick up crud to block them; I'm sure the tank isn't completely full though. I might drop the whole service station out in future and do a real clean up on it or maybe replace it, the part isn't insanely expensive. I do wonder if the squeegees have lost their edge and perhaps aren't wiping the heads quite as clean as they should.

One thing which I think made a definite improvement was a force reset of the drop detector which I understand has a role in compensating for blocked jets.

I also ticked the "More Passes" box in the print driver. The user manual suggests that this is also intended to help compensate for blocked jets and it definitely worked.

Thanks to all for your interest,

William Chitham.

[deanwork]

Wow, sounds like you are doing everything correctly to get to the bottom of this. You did shake all your ink carts I assume. The Z doesn't get the kind of agitation that the Canon does, but if it is used regularly that shouldn't  be a problem but worth doing anyway. I always take mine out and shake them about every couple of months.

I did once hear someone talk about having to clean the drop detector because ink and paper dust dried on it. I'm sure you've already taken a can of compressed air and blown out all the areas in the carriage and head assembly. Cotton dust is the primary reason the Z would have issues with micro banding in my experience, other than a bad head. If you are not seeing ink marks on your prints that is a good sign that the problem is not with the waste tank or even wiper blade. Though I would clean the wiper area regularly with distilled water.

If it were me in this situation I'd try to take a look at that drop detector if you can get to it. Also just for the hell of it I would try a different icc profile if you haven't already, like one not make by the Z, such as a generic  paper profile from one of the media manufacturers just to see if there is any difference there.

[tonywong]

Have you tried cleaning the contacts on both the printheads and the contact in printhead carriage?

[neilbarstow]

Thanks for the all suggestions. As I said in the original post I replaced all the heads and ran through all the alignment and advance calibrations. I don't think the PCA is at fault, if that was causing nozzles not to fire I'd expect the same ones to be out after replacement which wasn't the case. The printer is switched on all the time and used nearly every day.

Hi William, are you in the UK? I had mine fixed by a very good repair guy a couple of weeks ago. Les Sheppard at www.1stcall4service.com
I reckon if your heads are being accepted there's no issue with either carriage or contacts. Maybe there's an airlock in the feed pipes, I saw a Youtube about that sucking some ink through through with a syringe.
Wrong printer, but this may help get you started: https://www.youtube.com/watch?v=p7oLzlb1Buk