The present disclosure relates to a liquid electrophotographic ink developer unit. The unit comprises a developer roller, and a secondary roller that co-operates with the developer roller. The developer roller is formed of a material having a specific resistivity of less than 110.sup.6 .Math.cm. The secondary roller is formed of a material having a specific resistivity of 110.sup.4 to 110.sup.9 .Math.cm.

An example developer unit includes a developer roller. The developer unit also includes a set of electrodes proximate to the developer roller. The set of electrodes form a cavity. The developer unit includes an inlet to the cavity. The inlet is to receive printing fluid. The developer unit includes an insert in the inlet. The insert is to distribute the printing fluid evenly in the cavity.

In one example, a developer roller for liquid electrophotographic printing includes a cylindrical metal inner core, a rigid conductive plastic outer core surrounding the inner core, and a compliant exterior surrounding the outer core.

A method for treating a substrate is provided herein. The method includes providing a substrate and applying a composition to the substrate to form the treated substrate. The composition includes a binder, a binder additive, and an aluminum salt. A method for improving adhesion of an image to the treated substrate is also provided herein. The method includes providing the substrate, applying the composition to the substrate to form the treated substrate, and applying a liquid toner to the treated substrate to form the image on the treated substrate. A printed material exhibiting improved adhesion of the image to the treated substrate is also provided herein. The printed material includes a treated substrate. The treated substrate includes the substrate and a coating disposed on the substrate and formed from the composition. The printed material further includes the image disposed on the treated substrate and formed from the liquid toner.

Herein is disclosed an electrostatic ink composition, wherein the composition is formable by combining: chargeable particles comprising a resin comprising a polymer having acidic side groups, and a cyclic anhydride. Also disclosed herein is a method of forming an electrostatic ink composition, and a method of electrostatic printing.

Herein is disclosed an electrostatic ink composition, wherein the composition is formable by combining: chargeable particles comprising a resin comprising a polymer having acidic side groups, and a cyclic anhydride. Also disclosed herein is a method of forming an electrostatic ink composition, and a method of electrostatic printing.

This disclosure relates to a liquid electrophotographic composition comprising a thermoplastic polymer resin, a charge adjuvant, microspheres, and a liquid carrier. Each microsphere comprises a shell of material encapsulating a gas. The microspheres are present in an amount of 5 to 90 weight % of the total weight of solids in the composition.

Disclosed herein is an electrostatic ink composition comprising a component selected from a fatty acid ester having a plurality of hydroxyl substituents and a fatty acid amide having a plurality of hydroxyl substituents. Also described herein are scratch-off structures and methods for producing them.

Disclosed herein is an electrostatic ink composition comprising a component selected from a fatty acid ester having a plurality of hydroxyl substituents and a fatty acid amide having a plurality of hydroxyl substituents. Also described herein are scratch-off structures and methods for producing them.

A calculating portion 300 acquires resistance of a carrier liquid in a carrier tank. A resistance calculating portion 302 acquires the resistance of the carrier liquid on the basis of a liquid amount of a carrier liquid for each of numbers of times of passing of the carrier liquid through a separation and extraction device and resistance of the carrier liquid for each of the numbers of times of passing of the carrier liquid through the separation and extraction device. The liquid amount of a carrier liquid for each of numbers of time of passing is calculated by a deterioration degree distribution calculating portion 301 and is stored in a memory 201. As regards the resistance of the carrier liquid for each of the numbers of times of passing, the resistance of the carrier liquid after passing through the separation and extraction device is stored in the memory 201 in advance for each of the numbers of times of passing. A carrier supply discriminating portion 202 discriminates whether or not a carrier liquid for supply should be supplied, on the basis of the acquired resistance of the carrier liquid. A controller 200 controls a pump 51 for supply on the basis of this discrimination.