The use of ink-jet printers is increasing rapidly in demanding small and wide format applications such as advertising posters, engineering drawings and photographic reproduction.  In addition, many niche applications are also emerging.  The quality of the final image is determined not only by the printer technology but also by the chosen ink and medium.  In the latter case the use of a coated substrate is essential if high print and colour quality is to be maintained.  However, it is imperative that the coating on the paper/film is correctly formulated to guarantee the requisite, high quality, image.  The choice of pigment within the formulation is extremely important and has a major impact on the quality of the finished product.

Silica is the pigment of choice in numerous media coatings.  Because of its controlled, highly porous structure, synthetic amorphous silica gives several benefits to the ink-jet formulator when compared to other pigments such as treated/modified clays, kaolin and calcium carbonate.  The presence of silica in the coating favours fast drying of the ink, controlled dot size and shape, crisp colours and good image resolution.  Both smudging of the ink and strike through are also minimised.

From its unique position established through both gel and precipitate technology, PQ Corporation, a world-wide manufacturer of high quality silica, is able to offer the extensive GASIL range of pigments suitable for ink-jet coatings based on controlled silica particle morphology.  Coatings manufacturers benefit from our extensive range of products that allow increased flexibility in high performance coatings formulations.

Influence of Gasil silica properties on paper performance

Paper performance requirement		GASIL silica property requirement
Fast	Ink drying rate	High pore volume, large particle size
High	Colour density	High oil absorption, high pore volume, large particle size
High	Print definitions	High oil absorption, low particle size
Low	Colour to colour bleed	High pore volume, large particle size
Low	Wicking or feathering	High pore volume, large particle size
Low	Dusting	Tight particle size distribution, low oil absorption
Excellent	Colour gamuts	High silica purity, high pore volume, large particle size
Low	Strikethrough	High pore volume, large particle size
Low	Coatings viscisity	Low pore volume, large particle size
High	Coatings weight	Low pore volume, large particle size