Ink bleeding + banding on HP Z6100

[jonkovach]

I am printing to an HP Z6100. I will be printing full coverage panels, quite nicely, for about 45-60 minutes, then all of a sudden the ink starts banding and if you look closely at small letters and lines, the ink is actually fizzing out and bleeding... I attached a few images to show what is going on - if you need higher resolution images, let me know and I can email them to you...

I have NO idea what is going on. I will clean the printheads and sometimes run an alignment, and it will go away.... but it comes back. The printheads are not old - they are all within their warranty period. I have replaced them, and it helps, but it still comes back.

What the heck is going on?????

Not sure if this is the correct forum, or if wide format would be a better spot.... sorry.

Thanks,
Jon

 

[smiller]

banding on HP Z6100

banding on HP Z6100

The banding appears like typical print pass banding for a scanning inkjet when printing in one of the faster print modes, such as single pass bi-directional printing.

Although it will print much slower, consider printing in one of the higher quality print modes which will use multiple passes for each spot on the page (sometimes up to 4, 6, or even 8 passes) and in some modes uses uni-directional printing (although with 4 or 6 passes it bi-directional should be ok). Depending on the driver, these modes are sometimes referred to as "Best" ior "High Quality" instead of the lower quality "Fast", "Draft", or even the default "Normal".

This should help with the banding and it can even help a bit with the bleed (due to slower ink laydown).

- Smiller

 

[jonkovach]

Well, actually, I am in the highest print quality mode there is. I print at 10-pass, bi-directional. Could it be that this is TOO many passes? I was printing at 8-passes for a while, and saw the same thing going on, but thought it wasn't enough passes.

Any thoughts on that?

 

[smiller]

banding on the HP Z6100

banding on the HP Z6100

Interesting. Several questions that may help.

Is it only on the black?

What is the spacing of the light/dark bands in the images? (i.e. distance from dark band to dark band).

Are the bands horizontal relative to the printing scan direction?

When you clean printheads or replace them, did it slowly come back or just suddenly switch and start banding?

- S

 

[jonkovach]

Yes, it is absolutely only on the black. Sometimes I see it in the black lettering after printing for a while.

The spacing of the bands is just about 5/32" from dark band to dark band.

The bands run parallel to the printheads - i.e. when I'm standing looking at the printer, they are going left to right, parallel to the floor.

After I clean/replace heads, it seems to slowly come back. It gets progressively worse.

All these answers seem to lead towards it being an obvious printhead problem, but I swear it's gotta be something else! It's happing on all my Z's (I have 3), and it only happens after printing for an extended period of time.

 

[smiller]

banding on ZP6100

banding on ZP6100

Given the height of the printheads you are using (about 0.88") and if the printmode is 10 pass, then the size of the bands indicates that it's an issue with the nozzles on the black printhead.

So I agree with you that it seems to indicate an issue with the black printhead.

Another possibility, which I doubt is the case based on your description, is that the black ink cartridge is out and that it isn't reporting it correctly to you. The reason why it will start working is that ink always slowly drains down to the bottom of the cartridge, so you get some ink in there at first, but soon it goes out. This would be easy to test because it should fairly quickly simply run out of ink and only produce a few streaky lines. But that could also damage the printhead. You can also pull out the black cartridge and hold it in one hand and a full cartridge in another so see if it feels really empty or fairly full. The reason I doubt it is that you mention printing fine for 45-60 minutes... that is a long time of good printing and a nearly empty cartridge would probably have issues very quickly.

There's a small chance there's simply an issue with the black cartridge delivering ink at the rate the printer needs, so it gets starved after awhile. If you have a spare black cartridge, trying it may be worth the effort.

If it's the printhead you may try printing a draft (single pass) document or a nozzle test pattern. In either case, any issues in the printhead will become very visible and you can then replace it and do the same test again.

However, you said you've cleaned and replaced the black printhead and it eventually came back, so that's a mystery.

Finally, given that 45-60 minutes of printing is a long time, I'm wondering if it's some issue with the duty cycle of the device. This is a stretch, but if you are printing a lot of blackout, maybe the printhead is overheating or the ink delivery system is starving the printhead. A test for this is if you stop printing, wait a few minutes and start again, without doing anything else, and the problem goes away for awhile, that may be an indication of a problem like that.

If none of this helps and it's under warranty, I would take that option.

 

[smiller]

banding on HP Z6100

banding on HP Z6100

I also saw your posting on printheads scraping the paper. Is this related? It certainly seems like it could be and could explain both the banding and the feathering.

 

[jonkovach]

Update - I printed all day today. I had it rest about 15-30 minutes between large prints... large prints being 58" x 72"... no banding or feathering all day long. I don't really think it has anything to do with the ink cartridges - I go through a lot of ink, and replace them quite often. Also, I see this happening on two of my Z's... so it's a common problem to all the printers.

I have posted on scuffing, yes. I am still struggling with that issue. However, I haven't seen any scuffing on this printer in quite some time. I'd venture to say that scuffing is not causing this problem... though it does lead to other problems.

At this point, I really don't have any other information... still waiting for it to band again so I can run a printhead diagnostic print.

 

[Carl Couchman]

The following instructions are all accessible from the front panel of the printer.


1. Print special diagnostic print to isolate the problem print heads
a. Go to setup menu (This is on the bottom with the printer icon)
b. Once in this menu press the down arrow and cancel button at the same time (Service menu)
c. From the service menu scroll to and enter Service Utilities
d. Enter Diagnostic print
e. Choose Image quality user plot (follow instructions on screen)
2. Observe the 8 solid color squares representing each print head color to isolate the problem print heads
3. Clean the problem head
a. From the main menu pick ink (Top line has ink drop symbols)
b. Choose image quality
c. Clean print heads
d. Choose the print head color in question
4. Return to step 1 and 2 (see if problem is resolved if not go on to step 5)
5. Check head info (this may help to further isolate the specific head with a problem that may still be under warranty)
a. Go to ink menu (Top line has ink drop symbols)
b. Print head info
c. Pick one of the two specific heads in question
d. Check info to see how much ink has fired through the head. (If it is in the 1000 range it is suspect)
e. Check other head of same color as above.
6. Replace print heads
a. Follow front panel instructions for print head replacement
7. Verify problem solved
a. Go back to step 1 to make sure the problem has been resolved