Abstract: A liquid electrostatic ink composition is described comprising carbon nanotubes; a resin; and a dispersant comprising at least one polysiloxane in an amount from about 0.01 wt. % to about 30 wt. % based on the combined weight of carbon nanotubes and resin. In some examples, the polysiloxane is a trisiloxane and has at least one polyether group. Also described is an environmental sensor comprising a printed conductive trace formed by printing an electrophotographic ink composition comprising carbon nanotubes, a resin and a dispersant. The dispersant may be an organic hydrocarbon based dispersant, such as a basic amine dispersant, or a polysiloxane dispersant.

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: 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.