Assistance Please - Mimaki JV3 160SP Issue

[Roen]

Down to the issue, I ran a thorough cleaning on our Mimaki JV3 160SP this morning (nozzlewash, carriage out and a manual head cleaning) as per my usual monday morning routine.

The issue came when I attempted to run a print. The print head would seem to create this odd banding (as the print head runs horizontally, these lines appeared vertically, progressing only in the middle of the banner/vinyl) as attached.

If I run the print at one end of the banner I'm using, it doesn't band. It only happens in the center of the machine as it prints. I've run a dozen cleaning cycles, checked the lines and I don't have a damn clue what the hell has gone wrong over the weekend/my cleaning.

I've run this machine for a year and a half now (we've had it for 4-5 years now and not once can I recall this issue). We've replaced our print heads once that I can remember, but I'm yet at a loss.

If anyone out there has any idea what the hell this banding is derived from, please assist me in what way you can, I'm at my wits end (and attempting to patiently wait for Tech support to get back to me...). I've attempted different layouts/prints, different substrates, different profiles yet the problem persists.

Anything would be greatly appreciated.

Thanks,

Roen

 

[Letterbox Mike]

Try cleaning your encoder strip.

 

[Roen]

That did it, thank you kindly!

Sincerely,

Roen

 

[gabagoo]

can you describe this encoder strip? Is it the piece of metal that runs behind the head and if you look at it and catch the light in it, it seems to have a pattern similar to a fingerprint? I ask this as I have never touched it and I have noticed since day 1 that on the side closest to my capping station it looks like it has a scuff running about 12" long. I have been fearful of touching it or trying to clean it as I have no idea how to care for it. what do you suggest for cleaning if indeed this is the encoder strip. Ironically at this end of the printer we always have a harder time of dealing with media compensation.

 

[Roen]

The encoder strip on the mimaki is that clear strip that is roughly 1" wide by the length of the machine that sits in behind the print head. (You can see it behind the black pulley line).

We just cleaned it with isopropyl alcohol and a very small lint-less cloth (you have to be very careful not to be too rough with the strip - I'm told it breaks easily). It seemed the problem I had was a few drops of grease got smeared onto the strip last friday when we lubed the machine up.

Everything's worked perfect since we cleaned the strip itself. Just annoyed that my predecessor and the tech guys at ND Graphics never mentioned this when they trained us on the machine a few years back.

* If you need to see a picture of the encoder strip, just type it into google under images and you'll see a roll of it to compare with.

Thanks and have a good one!

- Roen

 

[gabagoo]

OK so what exactly does the strip do?

 

[Letterbox Mike]

The strip has lines etched in it, there is an "eye" on the print head that reads the lines so it knows exactly where it's at left-to-right, and it bases the location and timing of the ink drops based on this. If the encoder is dirty, the print head gets confused and doesn't know it's exact location, and you start to get some wacky prints, like what Roen posted. His prints were unusual for a dirty encoder (must have been naaasty), normally your prints will start to "walk" in one direction, where each pass starts and stops shifted a little bit to the left or right, giving it a slanted or stair-stepped look.

If you ever start to see anything similar to what he posted, or your passes aren't lining up from one to the next and the print is walking off in one direction, or you have a print anomaly in one stationary location in the direction opposite of the head travel, check the encoder strip first.

 

[gabagoo]

The strip has lines etched in it, there is an "eye" on the print head that reads the lines so it knows exactly where it's at left-to-right, and it bases the location and timing of the ink drops based on this. If the encoder is dirty, the print head gets confused and doesn't know it's exact location, and you start to get some wacky prints, like what Roen posted. His prints were unusual for a dirty encoder (must have been naaasty), normally your prints will start to "walk" in one direction, where each pass starts and stops shifted a little bit to the left or right, giving it a slanted or stair-stepped look.

If you ever start to see anything similar to what he posted, or your passes aren't lining up from one to the next and the print is walking off in one direction, or you have a print anomaly in one stationary location in the direction opposite of the head travel, check the encoder strip first.

and how would you suggest cleaning it. alcohol? I tried a small section but the alcohol seems to leave a bit of a white film behind

 

[benjercorp]

it has a lot of lines that is read by a Encoder sensor then the main-board knows where the carriage is and where to drop the ink!!

 

[Letterbox Mike]

clean it very carefully... I use just a drop or two of alcohol on a LINT FREE cloth, gently wipe it and that's it. Don't soak it, don't rub it too hard. You just want to get the debris off of it.

 

[gabagoo]

thanks

 

[All Signs Inc.]

Unless these are made differently than the ones on the HP, we were told not to use alcohol because over time it can actually leave a slight cloud or haze on the strip. Instead just use warm water to clean it.

Just my two cents worth.

 

[genericname]

I've seen all manner of argument of the alcohol vs. water type, and out of nervousness, have only ever used the water method. Just that worked like a charm though, as we originally had prints even more severe than Roen's. A light pass with a damp, lint-free cloth did the trick perfectly.

 

[APC Tech NE]

Glass cleaner is my solution of choice. Better cleaning, no damage to strip.

 

[WB]

100% Looks like an encoder Strip to me...