Black nozzle issues - misdirection

[chorca]

Well, I'm still struggling with misdirected nozzles on this thing. Black just won't clean up, no matter what. I've soaked it for an hour or so with a coffee filter/cleaning solution, cleaned the wiper every time the head uses it, and made sure the dampers are working. For some reason, the black just prints really odd. A lot of misdirected nozzles are showing up, where when I first installed the head, it was fine. The other colors seem to be printing decently, so I'm really confused where to go from here. I've done powerful cleanings, head soaks, etc, to no avail.

Also, the capping station area has been splattering ink against the inside wall of the printer for some reason, I've yet to figure out why. The heads have ink sitting on the sides of them as well, which i've cleaned off more than once, but the stuff just returns, and I can't tell how.

Here's a couple photos of what I'm talking about:

This is the initial nozzle test after installing the new heads:


Now, after a bit of use:


Loads of misdirected nozzles on black. Some on light cyan as well, but I've usually been able to clean those up.

Here's the ink limit test from Flexi, showing what the misdirected nozzles are doing:


Any ideas?

 

[randya]

Could be that the head is physically damaged at the nozzle openings.

 

[chorca]

Could be that the head is physically damaged at the nozzle openings.

Is this something that can happen with new heads? I'm kinda confused, one day they looked great, the next they looked like that, and I haven't been able to get anything to affect it..

 

[thmooch]

Maybe check your black drain line. If it is clogged, the capping station could have black ink backed up drying on the head.

 

[chorca]

I cleaned the capping station lines and pulled ink manually through it with a syringe to make sure it was getting ink. The nozzles and the directions where they are misdirected in seem to stay the same, almost consistent with something stuck in them. I've only used OEM inks, just bought Mutoh cartridges from Fellers and slapped them in after flushing the whole system out.

I'm contemplating taking that head out and doing a light ultrasonic cleaning on it to see if i can't get the thing to knock it off. Wondering if somehow some black particulate ink made it's way through the (new) damper into the (new) head.

 

[randya]

Misdirected nozzles can be from a number of things.

Most likely is ink dried at the nozzle opening.
The other is damage.

In a perfect nozzle, ink is squeezed out by applying a voltage to a piezo in the head.
This voltage 'curve' uses the head ranks to create the optimal drop at the correct time for best printing.

If the nozzle is distorted by damage or dried ink it will change the way the drop falls from the nozzle, deflecting it away from its desired path.

Heads can be damaged by handling, installation, head strikes, etc.

 

[bpatrick3]

Have you tried to print solid black bar 50" wide by 3" high and just let that black fire away and try to clear itself?

 

[wedosigns]

I have just gave life back to an old cj500. This printer sat for two years with the ink in it. The heads were completely clogged. I soak the heads in 3/8 of cleaning solution, and a many times a day I would pull gently with a syringe from the damper side of the head(while keeping it in the fluid) untill 4 days latter I was getting clear cleaning fluid through them.
I have in the past pushed cleaning fluid through, but I think it lodges the dried ink particles in the jets.
My theory is when the fluid is pulled through the damper side of the head that the fluid will eventually carry the dried ink particles out the top of the head. When the fluid is pushed through it seems to me that dried ink particles will distort the jet and cause even more deflection.
Bruce

 

[bpatrick3]

makes a lot of sense wedosigns---Good Info

 

[chorca]

I may try pulling the fluid through the damper side with the left head. It's pretty bad. I'm going to at least pull it out to inspect it. These things have less than two days of solid use on them, which is kinda disappointing, so hopefully I can get this one working again.

It's also the same one I've been working on in my other rebuild thread, a Falcon I 46".