The most important tool for digital printing is obviously the printer. Several components makes up a printer, and doubtlessly, the print-head is the most precious, most vital, and certainly the most expensive part of a printer. Printing operator would maintain it above all their equipments, trying what they might, to preserve it in its finest condition. However, as they have found, the nozzle would still block frequently, causing inconvenience and sometimes even delaying their job. What causes the mysterious blockage of print-heads? We have been investigating into why this problem keeps reoccurring. Below shows the datum we got on the intensity of average ink when we sent it to the national analyze centre.The sizes of pigment molecules in solvent ink are as follows: 4800nm-5500nm: 10.5% 1000nm-4000nm: 31.6% 200nm-1000nm: 46.6% 100nm-200nm: 10.8% Less than 100nm:0.3% In nowadays, ink manufactory normally grinds the pigment molecules up to 0.2 micrometres [that is 200nm]. However, as the above information shows, only 11.1% of the produced molecules are below or equal to 200nm, while 88.9% of them [or the rest] are larger. Why is that? It is because of attraction between the electrons of the molecules, which binds numerous pigment molecules together, forming a cluster of ink pigment. Someone maybe will have this doubt: Since most printers are equipped with filters, so logically, the oversized pigment bonds should be all filtered, blocked outside the printing head, then why is it, that they still block the printing-head? The reason is, the filter could only block out solid particles which are bigger than the filter holes. For those clustered pigment molecules, they could reshape under pressure and pass through the holes, no matter how big they are. From the above introduction, we can conclude that the blockage problem come from the pigment molecules bonds within the solvent ink, and these bonds could not block out by through filters. So, how could this problem, one that has troubled printing industries for a long time, be solved? Evidence shows that Ultrasonic Ink Tank could completely solve this problem! Many printer operators, after using Ultrasonic Ink Tank, were baffled by the immediate effect; no matter how blocked printing head was! Before using the this ink tank, the printing head would have to be cleaned once every few hours, or even more frequently. Now, the blockage problem never reoccurred that frequently. This seems very mysterious, but is fairly simple in truth. Ultrasonic Ink Tank has the ability to separate the clustered pigment molecules, making the pigment molecules return the original status, under 0.2 micrometres.