Hp Fb700 - Ink Banding

[theyllek]

I've had a recent issue with our HP FB700 with banding. And it's only on the first print it does, or sometimes right after a cleaning in the middle of a full day.

It's as if the 3/4 of the nozzles are clogged, but the jet health pattern and everything is fine. If I'm printing 2-sided 4x8 sheets, the first side will look horrendous, and then flipping it over to print he second side, everything looks fine. The only difference being flipping the sheet over. And every sheet after that will be fine as well.

I'm not getting any errors either, which is annoying.

[Reminds me of when we had a cable issue at the house - perfect service during the day, but at night it was shoddy and frequently kicking us off. Turns out there was bad connection and during the heat of the day the metal expanded enough to make a good connection, and when it cooled off at night and shrank back, bad connection. ]

I've already done the usual things, restart, cleaning-auto and manually, cussed/threatened/sweettalked/talked dirty to it, checked to make sure all the heads were seated correctly, etc.

Any ideas? I'm not dead in the water, been printing a scrap sheet at the beginning of each run instead of waste good stock, but it's not a long term solution.

I'll try to get some photos later on today if it's helpful.

 

[Stella_FB700]

I've had a recent issue with our HP FB700 with banding. And it's only on the first print it does, or sometimes right after a cleaning in the middle of a full day.

It's as if the 3/4 of the nozzles are clogged, but the jet health pattern and everything is fine. If I'm printing 2-sided 4x8 sheets, the first side will look horrendous, and then flipping it over to print he second side, everything looks fine. The only difference being flipping the sheet over. And every sheet after that will be fine as well.

I'm not getting any errors either, which is annoying.

[Reminds me of when we had a cable issue at the house - perfect service during the day, but at night it was shoddy and frequently kicking us off. Turns out there was bad connection and during the heat of the day the metal expanded enough to make a good connection, and when it cooled off at night and shrank back, bad connection. ]

I've already done the usual things, restart, cleaning-auto and manually, cussed/threatened/sweettalked/talked dirty to it, checked to make sure all the heads were seated correctly, etc.

Any ideas? I'm not dead in the water, been printing a scrap sheet at the beginning of each run instead of waste good stock, but it's not a long term solution.

I'll try to get some photos later on today if it's helpful.

Send photos please - i have a FB700 i run constantly and may be able to help you.

 

[theyllek]

Lets see if I can get this to upload.

The print on the left is first one out yesterday morning - nearly perfect nozzle check yet it prints like that. the one on the right, is just flipping the sheet around to the other side. It has been doing this every day the last week or so. And I did try just running an extra cleaning in the morning, even tho it's left on to do auto-maintenance all the time, no change. Sometimes the 'bad' print is worse than this - but I do nothing in between the bad print and good print other then load/reload stock. no cleaning, no adjusting nothing. grrrr, it's being quite contrary.

Any suggestions are welcome and feel free to ask the 'stupid questions' - I can't count the number of times I've been tripped up on the little things.

 

[Stella_FB700]

Is there any buildup on the print heads?
When was the last time you did a manual headwipe?
Have you done any head alignments? any manual calibrations?

 

[theyllek]

No build up on the heads - when this first happened I did a manual head wipe figuring that the other operator may have had a head strike or picked up a lot of dust/crud. The last one was done on Monday.

The heads were aligned last week when I replaced a bad head. I had this problem before I replaced the head so I used the opportunity to make sure all the cables in the carriage were seated correctly - and then checked again after replacing the head. I went through all the x, y, bidi, saber, calibrations manually.

It's just bogglingly that it'll print crap, then awesome the rest of the day. I'd love for it to just give me an error like every other machine I've ran.

 

[ColoPrinthead]

Is your vacuum working properly? I had similar issues in the past with a 500 and it's vacuum had died.

 

[Stella_FB700]

No build up on the heads - when this first happened I did a manual head wipe figuring that the other operator may have had a head strike or picked up a lot of dust/crud. The last one was done on Monday.

The heads were aligned last week when I replaced a bad head. I had this problem before I replaced the head so I used the opportunity to make sure all the cables in the carriage were seated correctly - and then checked again after replacing the head. I went through all the x, y, bidi, saber, calibrations manually.

It's just bogglingly that it'll print crap, then awesome the rest of the day. I'd love for it to just give me an error like every other machine I've ran.

Ha - I have been saying that since we got it - it has Action/Error messages for everything BUT. - Thanks HP
Trying to think of anything else to suggest.
I know i haven't received any banding issues just annoying overspray.
I'm thinking.. I'm thinking...

 

[Stella_FB700]

Poor output quality (apparent misregistration of colors, banding)
Auto Calibrations
Calibrates the position of ink droplets in relationship to each other and corrects for individual jets not operating properly.
You can also run the Manual Calibrations if necessary.
Kind of the only thing i can find from HP!

Wish i had more to help.

 

[theyllek]

Is your vacuum working properly? I had similar issues in the past with a 500 and it's vacuum had died.

This one doesn't have an cleaning station vacuum. It was bought used and didn't come with one - and cost like $$$$ to replace as it's wired for 240...we've been doing extra manual wipes to compensate and for the last 16 months since it's been running we've never had this problem.

Low-vac wise I figured I'd be seeing more issues than just this. It's not throwing any errors on the low vac being too low or high. I'll get my geek on later and download the complete log and see if I can see something there that's not enough to throw a huge warning. When I've had low vac problems in the past it's been more noticeable or consistent..color dropping out mid print, dumping ink out of the heads, etc. I didn't want to completely rule this out however, I've mostly learned not to do that lol.

 

[theyllek]

Poor output quality (apparent misregistration of colors, banding)
Auto Calibrations
Calibrates the position of ink droplets in relationship to each other and corrects for individual jets not operating properly.
You can also run the Manual Calibrations if necessary.
Kind of the only thing i can find from HP!

Wish i had more to help.

No worries! It's kind of an odd issue... but never hurts to see if anyone else has had the problem. I appreciate just being able to talk to someone who's ran this machine, or other inkjet equipment, everyone here is offset litho or docutech/xerox experience and no clue what I do.

If we have to we'll have to get a tech to look at it... I don't think a tech has looked at this since the original owners had it. By a stroke of luck I was able to get it up and running after being shut down for months and so far fix any of the issue's we've had. Found the service tech manual online which has been a huge help until this issue/quirk.

As soon as I get this large job out of the way I'll take a look at everything again, cables, tubes, vaccuum settings, calibrations, it feels like it should be something really obivious or something completely out there. Either way I'll share what I find out, perhaps help another person out.

 

[Stella_FB700]

No worries! It's kind of an odd issue... but never hurts to see if anyone else has had the problem. I appreciate just being able to talk to someone who's ran this machine, or other inkjet equipment, everyone here is offset litho or docutech/xerox experience and no clue what I do.

If we have to we'll have to get a tech to look at it... I don't think a tech has looked at this since the original owners had it. By a stroke of luck I was able to get it up and running after being shut down for months and so far fix any of the issue's we've had. Found the service tech manual online which has been a huge help until this issue/quirk.

As soon as I get this large job out of the way I'll take a look at everything again, cables, tubes, vaccuum settings, calibrations, it feels like it should be something really obivious or something completely out there. Either way I'll share what I find out, perhaps help another person out.

No worries,
I will do some more research on my end to try to assist you!
I run basically the HP FB700 / HP Latex and Epson. And am on here to try to assist people who love what they do like myself.
I might call my tech and see what he says - he normally gives me quick responses and ways to achieve quality.
Goodluck! I will try to find something - after work research!

 

[radelta1]

Here are my thoughts:
1) The shop/ink must at least 70 degrees Fahrenheit or more. If not, I have heard the thermistors may not register a drop in reservoir ink levels leading to print head starvation. One print head may be getting enough ink but the other print head of the same color drops out.
2) The thermistors may need to be cleaned. Just be careful to not break the glass.
3) The "permanent" ink filters behind the user end housing may need to be replaced. I think they are good for 20 to 40 liters of ink per color, perhaps less if you are using white ink.
4) The tubes from the reservoirs to the print heads may be clogged with sediment. I would disconnect them from the print head before flushing. I have heard of this happening with HP flatbeds with 5+ years of service.

Good luck.

 

[theyllek]

Here are my thoughts:
1) The shop/ink must at least 70 degrees Fahrenheit or more. If not, I have heard the thermistors may not register a drop in reservoir ink levels leading to print head starvation. One print head may be getting enough ink but the other print head of the same color drops out.
2) The thermistors may need to be cleaned. Just be careful to not break the glass.
3) The "permanent" ink filters behind the user end housing may need to be replaced. I think they are good for 20 to 40 liters of ink per color, perhaps less if you are using white ink.
4) The tubes from the reservoirs to the print heads may be clogged with sediment. I would disconnect them from the print head before flushing. I have heard of this happening with HP flatbeds with 5+ years of service.

Good luck.

Thanks for the information. The yellow reservoir was acting squirrely in the logs so I've changed out the O-Ring and Thermistor. Going to keep an eye on it and see what happens. We've had this press for almost 18 months, and the previous owners I'm not sure how long they had it, but it wasn't used very much, that I know. Will look into the ink lines and filters next if this doesn't work.

Thank You again.

 

[theyllek]

No worries,
I will do some more research on my end to try to assist you!
I run basically the HP FB700 / HP Latex and Epson. And am on here to try to assist people who love what they do like myself.
I might call my tech and see what he says - he normally gives me quick responses and ways to achieve quality.
Goodluck! I will try to find something - after work research!

Thanks

I run the HP FB700 mentioned here, Acuity LED 1600 and an IJP 200. Before that I ran Gandi Jeti machines and a Durst Rho and flexo presses... It's been a fun and interesting ride to say the least.

 

[radelta1]

Also, are you running 3rd party or HP ink? I am very reluctant to suggest 3rd party ink may be the problem; but, I ran 3rd party ink for a few months and had random episodes of head dropout until I went back to HP ink. I don't know if it was the ink or something else; but, the drop out started a few weeks after switching to 3rd party ink and stopped as soon as I switched back to HP ink. On the other hand, I know people who use 3rd party ink in FB500 / FB700s without any problems.

 

[theyllek]

Also, are you running 3rd party or HP ink? I am very reluctant to suggest 3rd party ink may be the problem; but, I ran 3rd party ink for a few months and had random episodes of head dropout until I went back to HP ink. I don't know if it was the ink or something else; but, the drop out started a few weeks after switching to 3rd party ink and stopped as soon as I switched back to HP ink. On the other hand, I know people who use 3rd party ink in FB500 / FB700s without any problems.

We are running OEM inks. I'm a little leary of 3rd party inks after a bad experience on another press - crap adhesion and color shifts, etc.

From chatting on here and with a tech for a different machine - I'm leaning toward air getting in the ink system... the challenge will be finding where it's at as it's not causing a MASSIVE issue...yet. I almost wish it was a more constant problem as it would be easier to trace. This waiting game is driving me crazies.

Excuse me while I go knock on wood, go outside turn around three times spit and curse...I totally do not want to jinx myself...

 

[Stella_FB700]

Can you flush your ink lines out?

 

[theyllek]

So after what feels like 47 other problems sorted out between 3 presses (I swear they talk to each other and conspire to go down when you are busy) we've tracked it down to the magenta valve in the airsystem manifold. I was really hoping it was just the goobered up thermistor that I was able to clean up :/

and I don't think you can replace just the valve, I think it's the entire manifold that has to be replaced.

 

[theyllek]

You can replace just the solenoid/valve. They are made by Festo. I've attached the label from the box for anyone else who may have a bad solenoid and not want to deal with the whole manifold replacement.

Popped that in and back to work, finally. Just in time as well! whew!

Once again, thank you all for you helps it did help with tracking down the issue

 

[FulSnygg]

You can replace just the solenoid/valve. They are made by Festo. I've attached the label from the box for anyone else who may have a bad solenoid and not want to deal with the whole manifold replacement.

Popped that in and back to work, finally. Just in time as well! whew!

Once again, thank you all for you helps it did help with tracking down the issue

Was it easy to replace the solenoid?