Role of ferrofluid in inkjet printing

Traditional inks used in inkjet printers are non magnetic, i.e. there is no remnant magnetic signal that can be detected once the ink has been jetted onto a surface. By incorporating Angstrom sized magnetic particles (typically 10% by weight) into the formulation, an ink is produced which is capable of retaining a magnetic signal and can subsequently be read by very simple and inexpensive magnetic recording technology. This class of magnetic inks has applications where low resolution characters need to be read quickly and with minimum error. Applications include bar coding and address dot codes for use in document sorting.

Fluid specifications

Fluids with saturation magnetisation of up to 300 Gauss can be produced, with viscosities as low as 2-3 cp (measured at 27°C). The particles used can be detected inductively or via a remanence measurement.