Weird head behavior - JV3-250SP

[genericname]

Multiple issues happening at the same time, including overspray in the cyan, but the one I really need to tackle is the head carriage gradually moving further and further to the left.

Printing in unidirectional, 360x540, 6-pass and 720x1440 16-pass
Can't reproduce issue with data cable swap. (or it just hasn't showed up yet)
Encoder strip and sensor are clean.
Slider board swapped with printer not experiencing this issue.
Print does NOT skew.

The head carriage acts as if there's an encoder issue, in that it gradually moves further to the left with each pass, to the point of slamming against the side barrier and spewing ink into the wiper area when it's supposed to return to the docking station. The one difference is that the prints are not affected. They're still straight as an arrow. If only I could get through a full-width print without having to reset the machine though.

Thoughts?

 

[genericname]

Okay, I think I've solved the issue.

Gutted the capping/wiper area and sopped up the mess that was left from the heads refreshing a good 6" away from the capping station. Re-wired some of the switches whose wires were compromised by solvent. Removed the encoder sensor and cleaned it. Replaced the encoder scale. Ran the Y Servo test. Adjusted the belt tension on the pulley. Same issue.

Re-ran the Y Servo test at 50% speed. Same issue.

Re-ran it again at 25% speed. Perfect positioning.

Removed the Y servo motor, opened up the bottom, and cleaned the glass encoder disk inside the motor.

Re-ran the Y Servo test at 100%, 75%, 50%, and 25% speed. No issues.

Printed a job this morning. No issues.

This whole thing. Two weeks of juggling jobs and hobbling along on one printer with intermittent overspray issues, running tests and cleanings on the busted printer between jobs, was because of a speck of dust on a piece of glass inside a motor.

 

[jfiscus]

wow, never would have guessed that. thanks for the follow-up post.

 

[Dizimoto]

Good info... Thanks

 

[genericname]

No problem!

Final (hopefully) update: Two weeks in, and absolutely no issues. The printer's running better than ever, and now I have another way to diagnose a very specific problem.