Mutoh 628 black ink fades as it prints

[Racegrafix]

So I have an issue with black ink, if it sits a few hours, it will nozzle check maybe 60%. If i do cleaning, it will nozzle check 10%. If I print test, it starts off gray lines and ends with lighter gray lines.

Replaced
printhead
dampers
pump
pump lines
cap top
ribbon cable

ran cleaner through it for 3 months. Filled cap top with cleaner and let it soak. I dont know what else to do.

 

[netsol]

So I have an issue with black ink, if it sits a few hours, it will nozzle check maybe 60%. If i do cleaning, it will nozzle check 10%. If I print test, it starts off gray lines and ends with lighter gray lines.

Replaced
printhead
dampers
pump
pump lines
cap top
ribbon cable

ran cleaner through it for 3 months. Filled cap top with cleaner and let it soak. I dont know what else to do.

on the rolands we can replace the felt pad in the captop. never had the experience with mutoh
did you change orings when you did ink llines?
once again, we wander into that area where the maintenance stationn confuses the hell out of me
it should be a suspect, i think

am i understanding that it is BETTER before a cleaning?

AT THIS POINT i would be considering mixing 5-10% acetone in my cleaner solution, but i routinely do this on my rolands, not yet much on the mutoh's

if you decide to try this, DO SO AT YOUR OWN RISK, and be sure to flush long enough to get all the acetone out of the captop (but, a bit of acetone SOMETIMES works wonders on problems like this

WHAT DO YOU MEAN "ran cleaner through it for 3 months" are you saying you did the world's longest head soak?

 

[unmateria]

Hi sounds like air on the system. Ink returns to the cartdrige slowly. Check dampers, tubing, orings, and cartdridge seal (the rubber where the needle enter)

 

[Racegrafix]

on the rolands we can replace the felt pad in the captop. never had the experience with mutoh
did you change orings when you did ink llines?
once again, we wander into that area where the maintenance stationn confuses the hell out of me
it should be a suspect, i think

am i understanding that it is BETTER before a cleaning?

AT THIS POINT i would be considering mixing 5-10% acetone in my cleaner solution, but i routinely do this on my rolands, not yet much on the mutoh's

if you decide to try this, DO SO AT YOUR OWN RISK, and be sure to flush long enough to get all the acetone out of the captop (but, a bit of acetone SOMETIMES works wonders on problems like this

WHAT DO YOU MEAN "ran cleaner through it for 3 months" are you saying you did the world's longest head soak?

I put cleaning cartridges in, with ink cards. So they went through the paces with cleaner instead of ink.

Yes, always better BEFORE a cleaning.

 

[Racegrafix]

Hi sounds like air on the system. Ink returns to the cartdrige slowly. Check dampers, tubing, orings, and cartdridge seal (the rubber where the needle enter)

Ah, cartridge seal...thats a great idea. Im not familiar with it, but I think you may be onto something.

 

[unmateria]

Cartdridge seal usually gets hard within 1 year so, yeah, it happened me several times. You can replace it, is very easy

 

[netsol]

60 second test.
take a q-tip and put a drop of armour all on the seal.
swab it around . Wsit 5 minutes and wipe
the sesl will swell & most likely seal
(if you don’t have other seals to swap out)

 

[Racegrafix]

Once I thought about it, i ruled it out. So, I tried a new set of cartridges, and then a second new set of cartridges. Same issue, all 3.
All colors currently fine, minus black

 

[Racegrafix]

It pulls black in through it when i do cleaning or little charge. Would that eliminate the dampers?

 

[unmateria]

Dampers act as antireturn valve and a little filtering. If ink doesnt return to the cartdridge, then that part is ok (from the dampers to the cartdridge tubing). If it returns... U have to check tubing, orings, seals etc because u have air entering that zone.

 

[Racegrafix]

Dampers act as antireturn valve and a little filtering. If ink doesnt return to the cartdridge, then that part is ok (from the dampers to the cartdridge tubing). If it returns... U have to check tubing, orings, seals etc because u have air entering that zone.

Makes sense.
So I found the issue for the most part. I tightened one nut of the tube the tiniest amount and it seems to have fixed that. Now at the exact time I fixed that, it stopped sucking ink at the cap top. You can hear the motor sounds different, so I replaced motor and pump, and lines, no change. Motor is running though. I truely hate this printer.

 

[netsol]

i believe you said you changed the orings. BOTH ENDS? (cartidge & damper?
it's much more trouble to change the carridge end.
ALSO did you follow vanderj's (solvent inkjet)
did you snip 1/4' off the hose when changing the orings?
be very careful, this is the part where you crack the manifold nipples and then you really will hate the machine

sMakes sense.
So I found the issue for the most part. I tightened one nut of the tube the tiniest amount and it seems to have fixed that. Now at the exact time I fixed that, it stopped sucking ink at the cap top. You can hear the motor sounds different, so I replaced motor and pump, and lines, no change. Motor is running though. I truely hate this printer.

 

[Racegrafix]

i believe you said you changed the orings. BOTH ENDS? (cartidge & damper?
it's much more trouble to change the carridge end.
ALSO did you follow vanderj's (solvent inkjet)
did you snip 1/4' off the hose when changing the orings?
be very careful, this is the part where you crack the manifold nipples and then you really will hate the machine

The orings are in the cartridge correct? If so, yes...I tried 3 sets.
I did not cut any off the damper hoses, mainly because how they are smaller at end and get bigger.

where is the manifold? How would you crack it?

 

[netsol]

No. Should be oring in the back where a small brass nut connects

 

[Racegrafix]

No. Should be oring in the back where a small brass nut connects

On this machine it didnt come with brass nuts, everything was plastic. I upgraded the plastic to brass with orings. This was at the dampers, I have not seen them anywhere else

 

[Racegrafix]

So I believe I see the issue. The end of the hoses from the carts is restricted from being too tight. But...I dont see those available for sale. I see the hoses, but it doesnt look like the nozzle is on them. Literally everything in the exploded view is labelled but those.

 

[Racegrafix]

scratch that, the hole is still bigger than the damper. I replaced orings in damper, no change.
I can 90-98% good nozzle checks, and prints terrible. Then nozzle check is terrible.

nozzle check - C = 100% Y = 100% M = 100% K = 80%
long cleaning C = 15% Y = 0% M= 40% K = 15%

I just dont know what else to do. The one part I want to change is not sold, you only get them with new printer. Im almost to the point of just trashing it.