Designjet T1200 carriage stuttering

[theengel]

I replaced the carriage unit because it wasn't recognizing a new printhead.

First of all, whenever the carriage is parked on the right, and the service station is NOT pressed against it, the carriage jiggles, as indicated in the video below. Secondly, it starts the replace printhead cycle, gets to the end of part 1 of 4, then starts part 1 of 4 all over again, looping endlessly. I called the parts vendor, who wanted to see the carriage diagnostics results before sending another carriage. I went back to the customer to do this, and the carriage came back "ok". I started the replace printhead process again, and this time it worked. The printer prints fine now.

But it still does this vibrating thing while on the right side. You can see it about 15 seconds into the video:

[Phil B.]

Re: Designjet T1200 carriage stuttering

I replaced the carriage unit because it wasn't recognizing a new printhead.

First of all, whenever the carriage is parked on the right, and the service station is NOT pressed against it, the carriage jiggles, as indicated in the video below. Secondly, it starts the replace printhead cycle, gets to the end of part 1 of 4, then starts part 1 of 4 all over again, looping endlessly. I called the parts vendor, who wanted to see the carriage diagnostics results before sending another carriage. I went back to the customer to do this, and the carriage came back "ok". I started the replace printhead process again, and this time it worked. The printer prints fine now.

But it still does this vibrating thing while on the right side. You can see it about 15 seconds into the video:

ok sounds like part of the cleaning station is preventing travel

does this one have a a lockable cover over print heads? sounds like the latch could be broken ( had in on a 550.

also check Motor - Belt - encoder and lube rails.

my bet is something blocking travel tho

[blackcat4866]

Re: Designjet T1200 carriage stuttering

My guess is that its not detecting the home position. The vibration is it's attempt to reach home position.

I'd start by removing the encoder strip. Clean it and very carefully examine it at the far right for scratches. I'd also check the carriage belt tension and clean the carriage rail. I see quite a bit of ink on the carriage bushings. Lubricate the carriage rail lightly with EU-1.

=^..^=

[Kiran Otter]

Re: Designjet T1200 carriage stuttering

I agree with Blackcat; my guess is it's the encoder strip. With how dirty everything else is it surely needs to be cleaned or replaced.

Kiran

[theengel]

Re: Designjet T1200 carriage stuttering

The thing is, the old carriage didn't do this. One of the first things I thought of was the encoder strip. I cleaned it, but didn't replace it.

I've looked everywhere for the answer to this:

How does the carriage know what "home position" is?

And the service station--with the caps moving back and forth. How does it know when those are in home position?

[Phil B.]

Re: Designjet T1200 carriage stuttering

The thing is, the old carriage didn't do this. One of the first things I thought of was the encoder strip. I cleaned it, but didn't replace it.

I've looked everywhere for the answer to this:

How does the carriage know what "home position" is?

And the service station--with the caps moving back and forth. How does it know when those are in home position?

How does the carriage know what "home position" is?

the encoder strip and turns of the carriage motor. Same with the 'cleaning/docking' station.

[Arcadian]

Re: Designjet T1200 carriage stuttering

How does the carriage know what "home position" is?

the encoder strip and turns of the carriage motor. Same with the 'cleaning/docking' station.

from my experience, the encoder strip is always an issue. i had one where just a small spot on the strip will make it stop, you cannot clean these strip. i tried that before and it made it worst. so getting a new strip, will help. but from the look of the machine, could be a bad photo sensor as well. ink is everywhere on that machine.

good luck.

[Lance15]

Re: Designjet T1200 carriage stuttering

....you cannot clean these strip. i tried that before and it made it worst.

IF you use alcohol, as Kiran and others have said many times before. Don't use alcohol. It can eat/wipe away those very small/thin marks on the encoder.

[Arcadian]

Re: Designjet T1200 carriage stuttering

IF you use alcohol, as Kiran and others have said many times before. Don't use alcohol. It can eat/wipe away those very small/thin marks on the encoder.

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.

[theengel]

Re: Designjet T1200 carriage stuttering

How does the carriage know what "home position" is?

the encoder strip and turns of the carriage motor. Same with the 'cleaning/docking' station.

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.

[Phil B.]

Re: Designjet T1200 carriage stuttering

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.]

Re: Designjet T1200 carriage stuttering

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]

Re: Designjet T1200 carriage stuttering

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