What is the reason for the ink flying phenomenon in UV printers?

Reasons for Difficult Drying of Small UV Printers

2. We need to check if the power of the UV lamp is turned on. Or if the power of the LED is turned on relatively low, it will result in the energy emitted not meeting a set standard. Normal UV lights should be adjusted to 60% to 70%.

What is the reason why the UV printer does not print??