Abstract: Herein is disclosed a method for concentrating a liquid electrostatic ink composition, the method comprising replacing a first liquid carrier in a liquid electrostatic ink composition with a second liquid carrier, wherein the liquid electrostatic ink composition comprises chargeable toner particles dispersed in the first liquid carrier; and removing the second liquid carrier to produce a concentrated liquid electrostatic ink composition, wherein the second liquid carrier has a boiling point below 100° C. and wherein the second liquid carrier has a lower boiling point than the first liquid carrier. Also disclosed herein is a concentrated liquid electrostatic ink composition producible according to the method.

Abstract: Described herein is a liquid electrophotographic ink composition comprising: a thermoplastic resin comprising a polymer having acidic side groups; a charge adjuvant comprising a complex of a metal(II) cation and two monovalent anions; or a complex of a metal(III) cation and three monovalent anions; or a complex of a metal(III) cation, a monovalent anion and a divalent anion, wherein each monovalent anion is independently selected from carboxylate anions having from 2 to 16 carbon atoms and alkoxide anions having from 1 to 16 carbon atoms; and wherein the divalent anion is selected form the oxo group, dicarboxylate anions having from 2 to 16 carbon atoms, and dialkoxide anions having from 1 to 16 carbon atoms; and a liquid carrier. Also described herein is a method of producing the liquid electrophotographic ink composition and a printed substrate.

Abstract: Method and devices for calibrating optical density reflective color fluids to be deposited on substrate are disclosed. Some methods comprise depositing a quantity of a keying color fluid on a first region of the substrate; applying a voltage level to a reflective color fluid application device; depositing, in response to the voltage level applied, a quantity of reflective color fluid on the first region of the substrate and on a second region of the substrate; performing reflectance measurements of the first region and of the second region; performing optical density calculations as a function of the reflectance measurements; varying the voltage level applied to the reflective color fluid application device in response to said optical density calculation until the optical density calculation is within a calibrated range of optical densities.

Abstract: A method for producing a cyan liquid electrophotographic ink composition includes: dispersing in a first portion of carrier fluid cyan pigment particles and inorganic spacer particles, the inorganic spacer particles having a particle size (d50) of 0.1 ?m or less, such that the inorganic spacer particles adhere to the cyan pigment particles; heating a polymer resin in a second portion of carrier fluid to dissolve the polymer resin; adding the dispersion of the cyan pigment particles having the inorganic spacer particles adhered thereto in the first portion of carrier fluid to the dissolved polymer resin in the second portion of carrier fluid; cooling the carrier fluid at a controlled rate to effect precipitation of the polymer resin from the carrier fluid such that a coating of the resin is formed on the cyan pigment particles having the inorganic spacer particles adhered thereto, thereby producing the cyan liquid electrophotographic ink composition.

Abstract: Method and devices for calibrating optical density reflective color fluids to be deposited on substrate are disclosed. Some methods comprise depositing a quantity of a keying color fluid on a first region of the substrate; applying a voltage level to a reflective color fluid application device; depositing, in response to the voltage level applied, a quantity of reflective color fluid on the first region of the substrate and on a second region of the substrate; performing reflectance measurements of the first region and of the second region; performing optical density calculations as a function of the reflectance measurements; varying the voltage level applied to the reflective color fluid application device in response to said optical density calculation until the optical density calculation is within a calibrated range of optical densities.

Abstract: The present disclosure relates to a method for producing a conductive liquid electrophotographic ink composition. The method comprises: heating a polymer resin in a carrier liquid to dissolve the polymer resin; adding conductive metallic pigment Particles to the carrier liquid; and cooling the carrier liquid to effect precipitation of the polymer resin from the carrier liquid, such that a coating comprising the resin is formed on the conductive metallic pigment particles; wherein: I) the polymer resin comprises (i) a copolymer of an alkylene monomer and a monomer selected from acrylic acid and methacrylic acid, and (ii) an ionomer of an alkylene monomer and a monomer selected from acrylic acid and methacrylic acid, wherein at least a portion of the acrylic acid and/or methacrylic acid groups are neutralised with metal ions; and/or II) a charge adjuvant is included in the coating that is formed on the conductive metallic pigment particles.