Overprint specific color - Workaround for missing nozzles

[Lady Who]

Hello there!
I have a Mimaki CJV150 with DX7 printhead and I lost a whole line of magenta, don't know if I would be able to recover it, but anyways...

I'm wondering if there may be a workaround to keep printing with some quality. For example, depending on the job, I'd adjust magenta density, change resolution and print profile and it's kinda making it. But I think there may be more...
Is it possible to overprint a specific color, like magenta only? If I create my own profiles, using bigger or smaller dots, does it make difference? (I still have to learn Profile Master)

Any ideas on how to keep going with only one magenta line?

Thanks in advance

 

[rjssigns]

Print in a quality mode and unidirectional. Can mitigate a host of issues.

 

[Lady Who]

Hello there!
After a lot of tests, I've found some options to keep working with missing lines. Quality mode and unidirectional is good idea, but it didn't get a good result with my issue. So, now I'll tell you what's worked for me with a whole line missing:

Basically you have 2 options: overprint or increase ink limit and density

a) Overprint: choose overprint 2 and reduce ink density of the colors that are working fine (see photos 1 and 2)
My example: one whole magenta line missing, then I choose overprint 2 and reduced ink density of Cyan, Yellow and Black.
Pros: print result is almost perfect
Cons: overprint is when the machine does the same pass 2 or more times (in this case, drops ink twice in each pass), so, printing is slower

b) Ink density: in this case, you keep using the same profiles you were used to, but increase ink density of the color with missing lines; If increasing density is not enough, also increase ink limits (Advanced color adjustment -> Setup > Select the color with missing line and increase ink limit in the "Whole" column. (see photo 3)

Pros of all methods:
• With some patience and as long as you have at least one line of each color, you can make adjustments to keep working and postpone bying a new printhead. I believe it can work even if you have lots of random nozzles missing: once you grasp how ink limits and density works, you can adjust it properly for your issues. Read Rasterlink Manual too on ink limits and these adjustments

Cons of all methods:
• There's no formula, you need to customize those adjustments to each artwork you're printing, so, you'll waste some time adjusting and testing before running each job (similar artworks can use the same adjustments though)
• Rasterlink and the machine don't know there's a bunch of nozzles missing, so, by using these tricks, machine will "think" and indicate that you are cosuming a lot of ink (but you're not because a whole line is not firing); so, you'll have to find a way to prevent the cartridge chip from burning and indicating end of ink. In my case, this is done by keeping pressed that thing (latch?) on the right side of the cartridge. And you also have to be very carefull to prevent the ink ending and air getting in the lines, once the chip is not working as it should do. I'll research more about it.

Hope it helps