JV 33 not printing any yellow

[stickerman12]

In the last month or so my yellow is totally out in the middle of my prints. It does not happen all the time. Sometimes I do and ink fill and it will fix it but lately that is not working as well. Also, after a few days of not printing, my magenta will miss about half of my nozzles in a print test and if a normal head wash does not get them back I do a custody wash to get them back. Is that appropriate to do a custody wash in this case?

Thanks for any help...

 

[SightLine]

Sounds like your machine needs some maintenance. How old are the dampers, capping station top, and pump?

 

[Vital Designs]

Having the identical issue with mine. Ink flow diagnostics are all good from the head up and the cap down so I am replacing the head Tuesday.

If you switch the magenta dampers with the yellow ones (leave the ink lines connected) what happens after a cleaning do a test draw? If you get yellow in the magenta slot and nothing in the yellow slot your ink lines are good. This could indicate your head is suspect. If magenta shows up in yellow spot, you could have a damper, o-ring, ink line or valve issue. I would troubleshoot in that order?

 

[stickerman12]

I bought the printer used factory refurbished and picked it up at the Mimaki Atlanta office so I do not know how old any of the parts are. It is set up as MCYKx2. When the yellow does not print, it does not print on either channel of the yellows. Not even a nozzle. When it does print yellow it is on both channels. Since this is the case, could it be a damper, o-ring, valve or a pump issue since it all of this on both yellow channels?

Thanks

 

[Robert M]

Cap top

Change the cap top first, then look at the dampers. I think the cap will fix it

 

[artbot]

if you don't have a new cap top just switch it with a good one on the capping station for a test. with all noise making things turned off in the room (ac, computer fans, etc) you will be able to hear the air/bubbles if the cap top isn't getting a good seal. and the pull at the syringe will be weak, not solid.

 

[SightLine]

Thats not an option on a JV33..... there is only one cap top on these.

First easy test I'd say to try would be to move the yellow lines and thier dampers to another channel temporarily to see if the problem follows the dampers/lines.

I'm thinking an o-ring or loose/leaking fitting at the yellow T junction behind the cartridge slots. I say this since it's affecting both yellow channels. It's not as likely that both dampers or the o-rings at both dampers would fail at the same time. I rule the capping top out since it affects both yellow channels. On a DX5 cap leak - one area or the entire head tends to be affected. The two yellow channels are positions 3 and 6 (on a JV33 the head is MCYKKYCM) which are not adjacent to each other so I'd think a leak would at least also affect black. That being said it might well be a minor capping leak and the yellow channels are just the most susceptable to the slight pressure loss.

Easy to remove the cover from the back of the cartridge station to inspect the lines and valves there....

The other main things that come to mind are potentially a bad ink lot at some point has clogged those dampers or worse the head manifold screens, or worst the head itself is starting to go south. I just replaced the head on ours. Same symptoms on black - first thing in the morning it woudl only be about 50% firing. 15 to 20 minute nozzle soak would get it back to about 95% - over a few months this got progressivley worse to where at best I coudl only get black back to about 75% firing. New head is firing perfect every day.