ink jet printing

Posted by charlesausten on March 1, 2017

The process of rapidly and accurately marking substrates such as cartons, envelopes, bottles and even eggshells is the domain of the inkjet printer. Different techniques are used by the major manufacturers but they broadly fall into two categories; CIJ (continuous inkjet) and DOD (drop on demand) - both require pumps as an integral part of the design.

In order to prime the print head, a pump capable of handling chemically aggressive inks is needed to draw the ink from a reservoir and feed ink to either the print head or to an intermediate accumulator tank. A diaphragm pump such as the Charles Austen model DL04 can provide the necessary performance; self priming, flow rates up to 0.4 l/min, chemically resistant wetted parts and a choice of 12 or 24 V DC drive, in brushed and brushless variants.

Some systems rely on a return or “scavenging” pump. Unused ink is collected and then drawn back into a reservoir under vacuum. This ink can then be reused as part of recycling loop. The pump must be able to run dry, have the necessary chemical resistance and be capable of continuous operation. Charles Austen Pumps offer the model D3 oil-free diaphragm vacuum for these arduous liquid scavenging applications. Again with brushless DC drive and a highly efficient reed valve design, the D3 can operate continuously to provide the necessary vacuum and flow when pumping gas/liquid mixtures.

The print head itself can be prone to clogging, particularly in dusty environments. One effective method of ensuring any airborne debris is kept clear from the print head is to use positive pressure air flow. A small linear air pump can be employed to feed low pressure air continuously to the head, preventing dirt and dust from clogging the mechanism. Charles Austen offers the LD range of small linear air pumps which are ideal for this application. The simple, low cost design will run continuously providing flow rates from 10 to 60 l/min of clean air at low pressure.