In an example, a method includes applying a liquid print agent comprising a carrier fluid to a photoconductive surface and reducing a proportion of the carrier fluid in the liquid print agent on the photoconductive surface at a first location during a print cycle of a print apparatus. The method may further include, during a non-print cycle of the print apparatus, adding carrier fluid to the photoconductive surface at the first location.

A printing apparatus is described in which a guide member biases a printing substrate against a plurality of electrodes comprised in an electrode array of the printing apparatus. A layer of wet printing fluid is comprised in the printing substrate. Based on an output of the electrode array when the plurality of electrodes is in electrical contact with the printing substrate, an index of a thickness of the layer of wet printing fluid is determined by processing circuitry of the printing apparatus.

In an example, a print agent application assembly includes a print agent transfer roller to receive print agent and transfer a portion of the print agent to a photoconductive surface and a print agent regulator roller to regulate a film thickness of print agent on the print agent transfer roller. The print agent regulator roller may include a nip forming region and a first mounting region. The print agent application assembly may further include a first resilient component which spans a diametrical width of the print agent regulator roller and acts on the print agent regulator roller outside the nip forming region to impart a lateral force to the first mounting region, the lateral force urging the print agent regulator roller towards the print agent transfer roller.

An example method of performing a null cycle in a liquid electrographic printer is described. The method involves collecting, at a photo imaging plate cleaning station, imaging oil deposited on a photo imaging plate during a print cycle. During a null cycle, the photo imaging plate cleaning station is controlled to apply the collected imaging oil to the photo imaging plate.

Described herein is a method for priming a print substrate for subsequently receiving a liquid electrophotographic (LEP) inkin which a surface of a print substrate is coated with a first primer using an analogue printing technique and a second primer is digitally printed to the surface of the print substrate coated with the first primer.

In an example, a method of wetting a print blanket includes receiving a null cycle trigger during a printing session. The method also includes maintaining printing voltages on a forecast BID (binary ink developer) that has been prepared to print a next color separation onto a photoreceptor, and applying wet null voltages to a non-forecast BID. The method then includes engaging the non-forecast BID with the photoreceptor to transfer fluid other than ink to the photoreceptor during the null cycle.

Ink-based digital printing systems useful for ink printing include a photoreceptor layer configured to receive a layer of liquid immersion fluid. The liquid immersion fluid includes dampening fluid, dispersed gas particles, and charge directors that impart charge to the solid particles. The photoreceptor surface is charged to a uniform potential, and selectively discharged using an ROS according to image data to form an electrostatic latent image. The charged liquid immersion fluid adheres to portions of the photoreceptor surface according to the electrostatic latent image to form a fountain solution image. The fluid portion of the fountain solution image can be partially transferred to an imaging member and/or transfer member to form a dampening fluid image, either or both of which may be electrically biased. The dampening fluid image is inked on the transfer member, and the resulting ink image transferred to a print substrate.

An example method of performing a null cycle in a liquid electrographic printer is described. The method involves collecting, at a photo imaging plate cleaning station, imaging oil deposited on a photo imaging plate during a print cycle. During a null cycle, the photo imaging plate cleaning station is controlled to apply the collected imaging oil to the photo imaging plate.

In an example, a method includes applying a liquid print agent comprising a carrier fluid to a photoconductive surface and reducing a proportion of the carrier fluid in the liquid print agent on the photoconductive surface at a first location during a print cycle of a print apparatus. The method may further include, during a non-print cycle of the print apparatus, adding carrier fluid to the photoconductive surface at the first location.

An image-forming apparatus includes an electrophotographic photosensitive member including a conductive base and a single-layer photosensitive layer disposed on the conductive base, the single-layer photosensitive layer including a binder resin, a charge-generating material, a hole-transporting material, and an electron-transporting material; and a developing unit including a developing roller that develops an electrostatic latent image formed on a surface of the electrophotographic photosensitive member with a developer including a toner in order to form a toner image, the developing roller being arranged to come into contact with the photosensitive layer. The ratio R/P of the content R [mass %] of the binder resin in the photosensitive layer to the pressing force P [N/mm] at which the developing roller is pressed against the photosensitive layer is about 11.5 or more and about 19.6 or less.