According to one example, there is provided an imaging system that comprises a housing, a rotatable polygon comprising multiple mirrored facets located in the housing, a laser to generate a laser beam to shine onto the polygon mirror and to reflect onto a target, and wherein, in use, the density of gas within the housing is such that turbulence-related optical distortion within the housing is not greater than a predetermined limit.

Herein is disclosed an electrostatic printing apparatus comprising: a photoconductive member having a surface on which can be created a latent electrostatic image; an intermediate transfer member comprising: a supportive portion; and an outer release layer disposed on the supportive portion comprising a base polymer matrix and an additive selected from carbon nanotubes and carbon black nanoparticles. The carbon black nanoparticles have a BET surface area of 700 m.sup.2/g or greater, the additive is dispersed in the base polymer matrix, and the base polymer is a silicone polymer. The electrostatic printing apparatus is adapted, in use, on contacting the surface of the photoconductive member with an electrostatic ink composition to form a developed toner image on the surface of the latent electrostatic image, then transfer the developed toner image to the outer release layer of intermediate transfer member, and then transfer the developed toner image from the outer release layer of the intermediate transfer member to a print substrate.

A liquid electro-photographic printing system, comprising: a binary ink developer assembly, a power supply arrangement, a switching arrangement, and a controller. The binary ink developer assembly includes a plurality of members defining a flow path for a printing fluid containing charged particles, the plurality of members including a first member and a second member that are arranged to generate an electric field therebetween, the first member having a plurality of segments. The power supply arrangement continuously provides a supply of voltages during a print operation, the voltages including a first voltage and a second voltage having a different voltage level from that of the first voltage. The switching arrangement switches the supply of voltages to the segments of the first member on an individual segment basis, to cause charged particles to be attracted to the first member in the individual segment when the first voltage is supplied to the individual segment and to cause charged particles to be repelled from the first member in the individual segment when the second voltage is supplied to the individual segment. The controller to determine timing of when to switch the supply of voltages to the segments.

Example implementations relate to a printing an image on a substrate and printing an ultraviolet-sensitive finishing mark on the substrate using ultraviolet-sensitive ink. The ultraviolet-sensitive finishing mark can be visible under ultraviolet light.

According to one example, there is provided an imaging system that comprises a housing, a rotatable polygon comprising multiple mirrored facets located in the housing, a laser to generate a laser beam to shine onto the polygon mirror and to reflect onto a target, and wherein, in use, the density of gas within the housing is such that turbulence-related optical distortion within the housing is not greater than a predetermined limit.

A liquid electro-photographic printing system, comprising: a binary ink developer assembly, a power supply arrangement, a switching arrangement, and a controller. The binary ink developer assembly includes a plurality of members defining a flow path for a printing fluid containing charged particles, the plurality of members including a first member and a second member that are arranged to generate an electric field therebetween, the first member having a plurality of segments. The power supply arrangement continuously provides a supply of voltages during a print operation, the voltages including a first voltage and a second voltage having a different voltage level from that of the first voltage. The switching arrangement switches the supply of voltages to the segments of the first member on an individual segment basis, to cause charged particles to be attracted to the first member in the individual segment when the first voltage is supplied to the individual segment and to cause charged particles to be repelled from the first member in the individual segment when the second voltage is supplied to the individual segment. The controller to determine timing of when to switch the supply of voltages to the segments.

The present disclosure relates to a process for printing a substrate. The process comprises applying an analogue primer over a print substrate. A transparent electrophotographic composition comprising a coupling agent is electrophotographically printed on the primer as a coupling layer. An electrophotographic ink composition is then printed on the coupling layer to form an image layer. The coupling layer is disposed between the primer and image layer and in contact with each of the primer and image layer.

In a case that a toner concentration of a liquid developer in a mixer is high and a liquid amount is small, when a supply flow rate of a carrier liquid by a carrier supplying pump is set, a carrier amount for concentration adjustment is preferentially assigned. Then, a remaining one is assigned to a carrier amount for liquid amount adjustment. By doing so, by a non-interacting function, a supply agent can be supplied to the mixer. That is, the carrier liquid can be supplied by decreasing the supply agent so that a liquid amount can be easily satisfied while improving followability of a toner concentration.

An example system includes a power supply. The power supply is electrically coupled to an electrode, a developer roller, and a cleaner roller. The system also includes a controller. The controller is to instruct the power supply to reduce, at a first time, a magnitude of an electrode voltage supplied to the electrode. The controller also is to instruct the power supply to set, at a second time, a developer roller voltage and a cleaner roller voltage each to about a wet null voltage.

Example implementations relate to a printing an image on a substrate and printing an ultraviolet-sensitive finishing mark on the substrate using ultraviolet-sensitive ink. The ultraviolet-sensitive finishing mark can be visible under ultraviolet light.