Why is filtration needed within the inkjet industry?

Filtration is a critical process within the inkjet fluid delivery system. The concept of a ‘clean' environment within the inkjet systems is significant and the correct configuration of filtration is paramount. To ensure and maintain optimised printer performance, the print-head nozzles and systems architecture must be protected from environmental and system debris, fibres, gels, ink agglomerates, and contamination from degradation of by-products.

Choosing the correct filter media and micron size will ensure the balance between correct flow rates, retention of oversized pigments, filter life to blockage and maintain the correct ink rheology and so droplet formation, enabling the optimised printer performance.  

The finished printed ink should still have all the intensity from optimal pigment loading, whilst retaining the fluidity to be correctly jetted through the printhead nozzles. In practical terms the balance will strip all oversized particles, foreign bodies and agglomerates whilst producing the full colour gamut and ensuring starvation of the printhead (printhead failure) does not occur.

The stresses subjected by the inkjet system can have adverse effects on inkjet formulations. High jetting (piezo) frequency, recirculation and shear rate of the fluid can account for precipitation of micro-gels within the inkjet fluid. Such concerns lead us to question not only the micron rating of the filter, but also the construction of the filter, which itself becomes a critical factor in protecting the printhead.

UV curing inks have shown a propensity to gel; therefore, our UV specific filters not only come with opaque black housing to ensure no pre-curing prior to the ink reaching the printhead, but also have multilayer filter packs to retain micro-gels.

Good filtration reduces risk from:

• Agglomeration
• Dust, fibre, foreign bodies
• Separation
• Printhead starvation
• Poor image quality
• Chemical incompatibility.

Ensuring the correct filtration of aqueous, UV or solvent based inks and fluids within inkjet printer results in the consistency of fluids and an increase in overall printer up-time.