INK JET INKS

3/1/2003

Ink Jet Inks: Ink jet inks come in two varieties -- dye based and pigment based. Dyes are preferable for broad based color printing as they will blend to create intermediate colors when mixed on the paper. Pigments are preferable for solid colors. Since users generally prefer not to change cartridges frequently, the preferred arrangement is dye based color inks and pigmented blacks. Most inks are water based, but once dried many inks are fairly water fast.

Most ink jet printers use separate black inks as blacks made by mixing red-yellow-blue(RYB) or cyan-magenta-yellow(CMY) tend to be muddy.

Color cartridges may use either RYB or CMY color schemes. RGB tends to be preferable for presentation graphics. CMY is preferable for photographic images.

Many printers use print heads with self contained ink reservoirs. Others store the ink separately.

Inks have varying chemistries that control such variables as drying rate; smudgeability; color intensity; tendency to clog the machinery; fade resistance; sensitivity to humidity; water fastness; match to other color systems; etc. In addition, any suspended particles must be very small and must not settle out. Details of the chemistry are closely held secrets, but one source lists the ingredients as 85% water, 5-10% organic solvents, 1-5% dyes, and small amounts of chemicals to control surface tension and discourage bacteria. Some technologies, such as Magnetic Ink printing are not widely available in ink jet technology and others such as resistance to fading clearly need work.