Adjusting colour channels.

[Forty One]

I'm noticing lately that my cyan is banding
I recently did a wrap for a client where the main colour was a purple. It banded like hell. I wasted a whole roll of wrapping film before I noticed it
All the other colours are fine.
Is there any advice someone can give me?
Jv33 130 CMYK.

 

[Solventinkjet]

How's the nozzle check look?

 

[Forty One]

Perfect.
The occasional missing nozzle in random places. But the usual clean sorts it out perfectly

 

[Mikee]

Perfect.
The occasional missing nozzle in random places. But the usual clean sorts it out perfectly

Firmware upto date..?

 

[Forty One]

Jv33 130 V 5.4
Mrl-III V1.4

 

[Solventinkjet]

It almost looks like a print feed issue but if the other colors are fine, that rules that out. I would check the head slant adjustment in service mode but if that's ok then it's most likely the head. You can try changing the cap top and dampers and see if that helps but at the end of the day, heads can have perfect nozzle checks and still be malfunctioning. Especially if your head is in the 3 to 5+ year range that is what I would suspect.

 

[Forty One]

Thanks.
Re head slant, would you mean if the head is slightly out of alignment? Eg. Twisted?
Under service mode for head slant adjustment, am I looking for a particular value? Is there a "normal" setting?
Thanks for your help. Greatly appreciated

 

[Solventinkjet]

Thanks.
Re head slant, would you mean if the head is slightly out of alignment? Eg. Twisted?
Under service mode for head slant adjustment, am I looking for a particular value? Is there a "normal" setting?
Thanks for your help. Greatly appreciated

Exactly. The head can be twisted so that it's not parallel with the platen and therefor it will print our of whack.

The head slant adjustment prints cyan and magenta dots over each other. The pattern is always sort of random but what you're looking for is the magenta and cyan dots to be on the same plane. You don't want to see magenta slightly diagonal from the cyan for example. You might want to get your hands on a tech manual. It's hard to describe without pictures.