Mimaki JV3-130II issues.. yet again.

[FelixCG]

Alright, so I was the guy that had the issues with the yellow a few weeks ago.
That all got resolved and isn't an issue anymore, I was able to print out several jobs flawlessly.
However, today it started doing this.
Basically, every second pass will be shifted slightly to the right, and then it'll go back to where it's supposed to be, and then go back to the right again slightly, and just repeat throughout the print, giving blurry, ****ty results. I've attached a photo where you can see in the three passes over the color, the middle pass is shifted slightly to the right.
I'm usually fairly good at troubleshooting for this thing, but honestly, I don't even know where to begin with this one. Any help is appreciated!

 

[just]

InkJet stairway to madness

first check the encoder scale. dust, ink spots, scratches, flies crap etc can cause this trouble. then check the encoder sensor. it's a black piece of plastic behind the carriage. The same, check it for the dirt inside, correct position(the scale must be strictly in the middle, scales top 1-1,5mm lower then sensor's slit top. Red light should be visible inside of the sensor. Move the carriage by hand from rightmost to leftmost position, checkin the scale inside the sensor. Check sensor wires.
Then examine small timing belt which connecting Y-motor and big(twin) pulley. If it's black inside - replace it. If broun - check tension. Too loose or too tensed small belt also can make this shift.

 

[artbot]

business card (white), flash light, and magnifying glass for inspecting.

if you want to locate dirt with a print, make a print with two pixel vertical lines ever one inch across the platen of the printer. maybe 3" x 54". there will be one vertical line that jumps over and is fine from the left on, the first pass will be fine. it's easier to see if you set your file to print at 2pass 360. at the point that you see the line disturbed, that is where the dirt or ink is.

the strip is polyester with a laser copy of the lines on it. one side is hardy and can not be washed off. the other side is delicate and the lines can be ruined if you clean too aggressively. also, take a computer air can and blast the reader.

dirty encoder strip only walks to the right. encoder reader issues walks either way or both ways.