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how does one clean the encoder sensor?

artbot

New Member
yesterday firewire, today encoder.

i've got a black head that is going bad and it's getting overspray near the capping station. this has caused the encoder strip to get a mist of black.

today i cleaned it off really well, thinking that was my issue. now it's perfectly clean and the printer is still staggering to the right dramatically.

attached is an encoder test file i use to diagnose encoder issues. (you might want to save it). it's a grayscale 60" x 1" of single pixel vertical lines one inch spacing. in your rip set it to about 720x720 4 pass UNI, overprint six times. this allows the printer to run the same track and you can quickly see the movement sideways without using up media. also you can set the Y/0 further in on your platen and see if you can isolate the area of the encoder strip that is skipping steps.

my question is:

how do you clean the encoder sensor on a jv3? i couldn't get a piece of card stock with iso' or anything in there. do you have to take it off? the compressed air can did nothing.

i am in dire straits with a sunday deadline. i really really must be printing right now. not doing repairs. so any ideas no matter how odd will be much appreciated.

aa
 

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aloninet

New Member
Hi,
In my experience you have 2 problems: 1. dirty encoder sensor 2. Infrared "eye" that reads the bar code also dirty. I had the same problem recently.
Clean the encoder sensor gently with a dry cloth, Do NOT! use a liquid solvent of any kind. If it does not help, try water with soap. Then gently clean the infrared "eye" with a long cotton stick, the infrared "eye" is located on the head on the inner side facing the encoder sensor more or less at the top middle of the head. If you do not succeed, you will need to open the Plastic lid of the head [2 small bolts jackets] do not touch anything there! It's all very sensitive and very fine tunes, try to reach the infrared "eye", and wipe it gently.

The truth is that this procedure should be done by a trained technician of the company that sold you the printer. Or technician of other service company.

Hope I helped you.
 

sfr table hockey

New Member
Normally you are the one we are asking such questions. If you are stumped this could be tough.

I have only had to use air on my Roland to blow the sensor off and clean.

Does the Mimaki have a test for the encoder strip?

Any chance a print adjustment setting can cause a print to wander?

Has it been getting worse slowly or did it start all at once?

If nothing else a bump for any other input.

Just seen the other post. Just more for input, Artbot is increadible at knowing how to fix these printers most of the time. This is not a slam on your post but more so you know who he is.
 

artbot

New Member
i looked at the service manual and there are two pages of badly translated tests. they compare all kinds of y motor distance vs. encoder distances to diagnose if the y motor or the encoder is the one losing steps. i find the whole two pages of describing the test unintelligible.

considering this is a low mileage printer and i've got the overspray already found on the encoder strip, i'm going to bet it's the encoder sensor. i just can't see how it can be cleaned thoroughly without removing it. the access is just to tight.

i think if there's not some "tape" this to that then run that passed this type of a cleaning option, i'll just take it off and get it under some good light.

i am down to counting wasted minutes. this truck is leaving at 10am sunday. and i don't see it all coming together.
 

artbot

New Member
well, took the encoder off. looked extremely clean under magnification. all i found was one single cat hair. ...which i think was about 99% the cause of it the drift. over about 30 passes, i'm off about 2mm. that would account for a single speck somewhere on the encoder. i'm going to go down the encoder strip with a flashlight, piece of white paper, and magnifying glass and i bet i find this missing speck.

update on this boring encoder thread. maybe it will help someone in a pinch someday..?

i found only one tiny speck of magenta ink. but that was the final fix. i've attached a pic of it dirty vs. clean. note that there is overspray on the "still dirty" photo. the head isn't perfect but it is printing much better now that the encoder is spotless.

shown in the final pic is a 1" x 1pixel line overprinted six times. the x advanced about 10 times to cover the inch.

aa
 

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Last edited:

ChicagoGraphics

New Member
You need to remove the sensor carefully and clean it with isopropyl alcohol let it dry then re install it. What ever you do don't blow any air from the outside of it somehow it can ruin it.
 

Fatboy

New Member
well, took the encoder off. looked extremely clean under magnification. all i found was one single cat hair. ...which i think was about 99% the cause of it the drift. over about 30 passes, i'm off about 2mm. that would account for a single speck somewhere on the encoder. i'm going to go down the encoder strip with a flashlight, piece of white paper, and magnifying glass and i bet i find this missing speck.

update on this boring encoder thread. maybe it will help someone in a pinch someday..?

i found only one tiny speck of magenta ink. but that was the final fix. i've attached a pic of it dirty vs. clean. note that there is overspray on the "still dirty" photo. the head isn't perfect but it is printing much better now that the encoder is spotless.

shown in the final pic is a 1" x 1pixel line overprinted six times. the x advanced about 10 times to cover the inch.

aa[/QUO
well done
 

sfr table hockey

New Member
This is the way to have a problem, find a solution and then post info that will help others. Good stuff.

But I guess thats what you get when you let your cat help you print. Good clean help is hard to find.
 

artbot

New Member
thanks for all the advice and encouragement. 20 hours and counting. my smoking hot girlfriend has been edge banding all after noon. i printed until 7:30am. sad thing is, ...as soon as i get this "shutdown" finished, i'm in another four day shut down on another project. not to mention, i'm supposed to do three bids/props this afternoon.

arrgh!
 

artbot

New Member
i blazed mine with air but that didn't work... taking it on and off what really easy. wish everything was that easy. it was so nice to see the printer tracking perfectly. i think it's been off by a few millimeters over an 8' length for the last few months. i just kept figuring it was user error/hillbilly flatbed issues.
 

petepaz

New Member
You need to remove the sensor carefully and clean it with isopropyl alcohol let it dry then re install it. What ever you do don't blow any air from the outside of it somehow it can ruin it.
for the strip on our roland they recommend alcohol no other solutions
 
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