UCJV300 Large banding lines and constant issues

[celledral]

I've had my UCJV for roughly 3 years and this problem started about my 2nd year into sparsely using it. If I print anything more than 30-40inches it would start printing out white or discolored bands across the entire vinyl, rendering it useless. I called my shop to to have their tech analyze it, but they just open the panel and pull the cables out and put them back. I don't think it's a permanent fix and they don't seem to know what they're doing. I then decided to just print at a max of 40inches to prevent these headaches, but now I'm finding myself needing more than that. Has anyone encounter these issues and know what I need to fix it? I'm thinking that I may need a new board, which would have been fixed under warranty, but the tech doesn't even know what causes the issue. Any help is appreciated.

PS Now I'm getting a SUBTANK ERROR

 

[Smoke_Jaguar]

The error is a subtank sensor error, can to go Menu> #Test > Sensor and then scroll through to subtank 8. There are 3 sensor zones, low, high and overflow and they will show as --- if the sensor isn't triggered. Note that a partially filled subtank can have a valid status of --- --- ---, don't be a goof like me and replace a perfectly good sensor. You also could have a ruptured subtank, and pressure (negative or positive) can be indicative of that. Can go to #Test> Air Pressure Test> Negative (or Positive) Pressure Test.

Note that I had a blown subtank and pressure was fine, so a good reading doesn't guarantee the subtank is good. Opening the head cover gave it away when I saw Cyan ink in the pressure/vacuum lines. If the heads don't get proper pressure/vacuum, they tend to 'bleed' ink everywhere. It will pool underneath the heads and drip all over your stuff. Not a tech, but I think it's pretty unlikely to be electrical, most likely in the air system itself.

 

[celledral]

The error is a subtank sensor error, can to go Menu> #Test > Sensor and then scroll through to subtank 8. There are 3 sensor zones, low, high and overflow and they will show as --- if the sensor isn't triggered. Note that a partially filled subtank can have a valid status of --- --- ---, don't be a goof like me and replace a perfectly good sensor. You also could have a ruptured subtank, and pressure (negative or positive) can be indicative of that. Can go to #Test> Air Pressure Test> Negative (or Positive) Pressure Test.

Note that I had a blown subtank and pressure was fine, so a good reading doesn't guarantee the subtank is good. Opening the head cover gave it away when I saw Cyan ink in the pressure/vacuum lines. If the heads don't get proper pressure/vacuum, they tend to 'bleed' ink everywhere. It will pool underneath the heads and drip all over your stuff. Not a tech, but I think it's pretty unlikely to be electrical, most likely in the air system itself.

Thank you for the informative post. I normally don’t see the subtank error too often. I’ll check it again tomorrow and try the settings.

Would you happen to have any experience with the large bands randomly printing?

 

[Smoke_Jaguar]

The large bands, in my case, were from the bad subtank. Since the subtank is connected to the vacuum/pressure system, they also control ink flow into the head. Bad subtank meant that that control was gone and it liked to just bleed ink. Also, make sure to wipe down the head carriage and check your capping stations. About to replace the one for head 2 since I noticed white ink pooling in the capping station. Didn't seem to cause issues during printing, however, it can cause ink to pool on the head.

 

[celledral]

The large bands, in my case, were from the bad subtank. Since the subtank is connected to the vacuum/pressure system, they also control ink flow into the head. Bad subtank meant that that control was gone and it liked to just bleed ink. Also, make sure to wipe down the head carriage and check your capping stations. About to replace the one for head 2 since I noticed white ink pooling in the capping station. Didn't seem to cause issues during printing, however, it can cause ink to pool on the head.

Sorry for another question. How do you properly do the pressure test and what values should be optimal. I tried searching on Google but there’s very little to no info on the ucjv300

Edit. Just finished the pressure adjustment. On the subtank sensor I’m seeing
—-/high/—-

My negative pressure is at 2.7x and positive pressure is around 15.x

 

[Smoke_Jaguar]

Negative value is -2.9kpa (+/-0.2) and positive value is 17.5kpa (+/-2.5). The throttle valve is underneath the left hand cover, loosen the locking ring and turn clockwise to tighten and raise pressure when dialing in the positive pressure. There is a delay as the system pumps up, so it is pretty finnicky, but can be dialed in pretty well with some patience. Likely the pressure is fine, so don't adjust unless you verify it is off. Thankfully this procedure is common on lots of Mimaki printers, it's the same as on a UJF-6042/3042 MKII for example.

Subtank sensor of high is good, means it has ink and it is full, sensor ranges are LOW/HIGH/OVERFLOW.