How to Maintain UV ink lines can be the most annoying issue about them. Check the following possible issues step by step and you will definitely fix the ink line issue:
- There is no ink in the ink container due to ink level sensor failing to tell that the printer ink is empty. This issue can also cause instability of the negative pressure system. So you may experience good printing sometimes but then banding issues happen because the air goes into negative pressure system, failing to fire the nozzle. The solution is to always keep ink level above 1/3 of the ink container. If ink level is too low it will be easy to cause failure of filling ink. This solution eliminates empty ink issue with physical ink being always full. We have experienced this situation where ink was almost empty but the ink level sensor failed to tell UV printer to pump more ink into the sub-ink tank. Consequently the ink pump pumps air to the sub-ink tank every time, causing big negative pressure value changes. This also causes the banding issue. That’s why we required all our UV printer customers to keep ink level always 1/3 level above in the ink container. This ensures to eliminate the ink empty warning failure issue by making the physical amount of ink always sufficiently full.
- The ink pump is clogged and so there is no ink go to the sub-ink tank and so there is no ink going to the print head.
- The ink line is clogged. Agfa, Mimaki, Mutoh and Roland UV ink lines are tiny and easy to be clogged. Lavaink’s solution is to replace UV ink line with industrial standard UV ink tubing, with an inner diameter of 2 mm and outer diameter of 4 mm. This ensures UV ink line is unclogged.
- The sub-ink tank ink level sensor failed to tell UV printer to pump ink. So no UV ink goes to sub-ink tank and so there is no ink going to the print head either.
- The ink line is loose or leaking. The most likely possibility is the section from the sub-ink tank to the ink valve. Solution: just replace old sub-ink tank with brand new sub-ink tank. Buy a good quality all-metal sub-ink tank, and never buy plastic sub-ink tanks. Some sub-ink tanks are metal but the connector is plastic and that is easy to break. Lavaink’s sub UV ink tank is composed of all metal parts, including metal connectors. Also all Lavaink sub-ink tanks are tested to guarantee they are sealed perfectly.
- Negative pressure tubing is loose or leaking. The most likely possibility is connectors. Double check all connectors
- Check negative pressure meter. It is normal if negative pressure meter cycles on and off for about 20 seconds. You know the ink line is loose or leaking somewhere if the negative pressure meter cycles on and off every two or three seconds.
- Release water from air pump. In some old UV printers, negative pressure is produced by converting positive air pressure and so there can be too much water in the air pump. Solution is to just release the air pump valve to let all water out. We experienced one Agfa UV printer customer who never released the air pump water, and when we discovered this, were able to release at least 3 liters of water from the air pump. This is the main reason that causes negative air pressure instability.
Keeping perfect negative air pressure
Keeping perfect negative air pressure is the key for UV ink line maintenance. Different UV printers have different negative air pressure values. The overall principle is that the higher negative pressure value, the higher the sub-ink tank level. For example, If your sub-ink tank is two feet from your printhead, then your UV printer negative pressure value should be at least -3.0. Agfa UV printer negative pressure value is set up at -3.8 but EFI Rastek H652 negative pressure value is just set up at -2.0~-2.5.
Why buy a good quality negative pressure system?
Monitor your negative pressure meter during the whole printing process. For example, Agfa UV printer’s negative air pressure is set up at -3.85 for colours. If this negative pressure value was changed from -3.85 to -3.5 and then that proves your UV ink line has some big issues. This large difference of negative pressure value 0.35 [-3.85-(-3.5)] is not allowed for UV ink lines. Max negative pressure value change is just 0.2. You must check our above instructions from step 1 to step 8. Check all of them step by step to figure out what is causing negative pressure instability.
Why buy Lavaink’s negative air pressure system?
Most UV printers’ negative pressure system is not good enough. Examples include old Agfa UV printers, which converts positive air pressure to negative air pressure. Changes in negative air pressure value during printing is also problematic. You have to monitor this negative pressure value during the printing process. If this value is lower than -3.5 it will cause the nozzle to fail to fire. Therefore the print banding issue could ruin the whole printing job. A bad negative pressure system will waste you a lot of time and money.
Buy a direct negative air pressure system
Lavaink’s negative air pressure system is directly produced by negative air pressure, and also controls the negative pressure value automatically to remain unchanged during the whole printing process. For example, if negative air pressure were set to -3.5, the negative air pump will automatically stabilize the pressure if the value falls lower than -3.5 until it goes back to -3.5 again. This ensures negative pressure value remains stable around -3.5 and the maximum change is less than -0.1. This guarantees Lavaink’s negative air pressure system delivers the perfect negative pressure value with stability. This is the most of important thing how to Maintain UV ink lines
Use the best quality uv ink to eliminate ink issues
Lavaink provides you the best quality uv ink from Japan Toyo UV ink and directly send out your uv ink order from our uv printer manufacturer. This ensure not only the best quality uv ink but also the lowest price.