A printing ink comprises a clear, transparent, polymeric carrier material and uniform, colloidal size charged color particles evenly dispersed therein. The carrier and the particles are adhesively bonded to one another so as to form a matrix which can collectively respond to an externally imposed electrostatic field to promote co-movement of a "bite" of ink to an imaging medium without change of the bulk particle/carrier ratio. During the printing process, the ink is melted and exposed to electrostatically charged latent image areas on a heated image cylinder, resulting in the transfer of the ink thereto in proportion to the electrostatic field strength. The ink exhibits a relatively sharp liquid-to-solid transition, thereby enabling rapid ink solidification and complete transfer from the imaging medium to the relatively cool printing substrate. Also disclosed is a printing method and apparatus that facilitate continuous, variable and on-demand color printing in conjunction with the ink. Use of essentially monodispersed, color-coated, colloidal size, spherical particles in the ink results in excellent color purity and chromaticity range.