Designjet T1200 carriage stuttering

[Phil B.]

i tried warm water, it made it worst just smears. even windex with no alcohol does work. if grease or oil gets on the strip, might as well replace it.

warm water and a mild soap always worked for me.

[Phil B.]

The encoder strip is a bunch of little lines. The encoder sensor sees these lines to tell how far it has moved when it moves in either direction. But those lines do not change at the very end of the carriage track. Nothing at the very edge is there to tell the carriage "here is our starting point." Encoders, as far as I know, never tell anything what home position is. They only tell things how far they have moved or turned. And besides--there is no encoder on the service station... not technically anyway. There is a wheel sensor, and I guess you could call that an encoder. But still, nothing is on that wheel to indicate what home position is.

i guess you didn't understand.

the encoder strip runs thru the carriage assm. it has photosensors in the carriage assm.

the main board tracks the movement via the info sent by the sensors watching the lines on the encoder.

then main board then uses that to 'plot' the movement across the rails. there are sensors in the cleaning station to move the wiper blade and capping station for the carriage assm. there is (best of my memory) no "Home sensor" like you would have in an ADF tracking the position of the scan lamp.

in all inkbased lifeforms I have worked on in my years, Brother/Hp/Xerox/Ricoh/Epson the encoder strip has ALWAYS been the weakest link in the chain. Also like I stated before it could also be: the carriage belt - dry carriage rails or something blocking movement of the carriage assm.

have you ever put a plotter back together and forgot to install the encoder ? the carriage will job until it realizes the encoder is not in place and then kicks an error code.

[Kiran Otter]

The 'home' position is determined by bumping the carriage into both ends of the carriage path. Again if the encoder strip is damaged, even slightly, it will throw this position off.

There is a black plastic piece screwed down just behind the carriage rail on the very right end that is the stop for that side's 'bump'. If you took it out and forgot to put it back, that would cause problems. The cutter on the other end is usually what the carriage bumps into on the T series, but in my experience it's OK if the cutter is removed.

The fact the problem didn't exist before replacing the carriage doesn't mean the encoder strip wasn't damaged when removed and reinstalled. Or that you have a bad carriage assembly. And I recommend never using anything other than water and a very wet paper towel to clean the encoder strip, or Simple Green; I use SG all the time and I've not had it damage an encoder strip.

Also make sure the service station is seated correctly if you removed it.

Kiran