JV33 Cyan banding, Just about replaced everything!

[Vital Designs]

Hey guys...

I have searched all the threads I could and can't seem to find a similar issue to the one I am experiencing.

3 year old Mimaki JV33-160 (lightly used)
I started printing a large area of cyan (4ft x 40ft section) and noticed slight banding. I stopped it and ran a test draw and a few nozzles were out. A couple more test draws and the nozzles were back. Did this a couple of times and the same thing occurs.

Other colors work fine with no banding which eliminates comp.

My guess, ink starvation/air.

Here is what I did:

*Replaced cap
*Replaced both cyan dampers
*Replaced both cyan ink valves
*each time opening the valves and pulling ink through the system from under the cap.
*All the usual cleanings and custody washes.

The only thing left in the ink system is the head but I am not convinced it is the head and not ready to guess on $2500.

There is also slight overspray at the ends of the print which goes away if not printing in bi-direction.

Anyone have any ideas? It's driving me crazy.

Thanks
Dave

 

[artbot]

first off. you should have popped your cyan damers/lines over to another position on the manifold to see if the issue followed the dampers. plus a new cap can perform worse than an older "conditioned" cap. you may have ink starvation still but further up in your system (pinched/clogged lines, bad ink etc.).

swap the cyan damper's position and see if the issue follows the lines. if it does not. place a different color at the cyan position and see if that color starves/bands.

i've seen these heads quite cheap on ebay and other suppliers. us jv3 guys envy the jv33 guys that you can get all new nozzles for all colors for $900.

 

[mustafade]

When I was replacing the head I saw those $900 heads on ebay but after talking to a few people I change my mind because I got scared.
What I been told that is there is a chance it will not print 1440 dpi res and if that happens good luck getting it exchanged with a new one.
May be they were just trying to scare me so that I would buy original head from Mimaki or Mimaki dealer. I don't know but it worked on me.

 

[Vital Designs]

first off. you should have popped your cyan damers/lines over to another position on the manifold to see if the issue followed the dampers. plus a new cap can perform worse than an older "conditioned" cap. you may have ink starvation still but further up in your system (pinched/clogged lines, bad ink etc.).

swap the cyan damper's position and see if the issue follows the lines. if it does not. place a different color at the cyan position and see if that color starves/bands.

i've seen these heads quite cheap on ebay and other suppliers. us jv3 guys envy the jv33 guys that you can get all new nozzles for all colors for $900.

Yeah Artbot, I had thought about doing the crossover to eliminate completely the entire system. Not real thrilled about running different color through the line but looks like thats next.

I have a 6 color Roland and I just recently replaced a head on it so I feel your pain too.

Thanks. BTW, you always have great input on printer issues.

 

[SightLine]

David from Sigmo is a member on here and on eBay is inkjet_parts. His DX5 heads are a bit more expensive but I've bought one from him before and it works perfect. I see a couple others on eBay as well including one as low as $650 from a US seller with 100% positive feedback.

I can see where different versions might only work with certain machines but I cannot figure why one might not work at some specific resolution. I would guess it will either work or it will not. Anyways I almost suspect it might be some other issue and I'd first try swapping your two cyan dampers with the outer magenta dampers to determine if the problem follows the lines or stays with the 2 cyan channels on the head. If it stays with the head there are a couple of electrical troubleshooting things you can do to further test if it is indeed the head or possible a bad resistor on the slider or main board. Could just be something like that causing low/intermittent/high voltage to one channel of the head.

Only other place I can think of might be a kink or slight clog in one or both of the cyan ink lines. To check that you can pull the back cover off the cartridge area and try swapping the lines with magenta from that point. Of course you might have just had bad luck with a new capping top and got a bad cap top but that seems unlikely as it had the issue both before and after and the pump seems unlikely since there is only one pump on these.

With swapping the dampers or ink lines it would only take a foot or so of printing a solid block of the color to flush it back out.