Hewlett-packard Development Company, L.p.

Hp Indigo B.v.

Ianywhere Solutions, Inc.

Eric G Nelson

David Sabo

Michel Assenheimer

Vitaly Portnoy

Amiran Lavon

Christopher Sean Tanner

Yoav Nachmias

Lavi Cohen

Evgeny Korol

Guang Jin Li

David S Vejtasa

Amir Ofir

Omer Gila

Thomas C Anthony

Michael H Lee

Seongsik Chang

Matthew Grant Lopez

James Pingel

John W Godden

Bruce J Jackson

Asaf Anufa

Ido Finkelman

Shachar Berger

Nadav Shalem

Anthony William McLennan

Ziv Yosef

Sagie Shanun

Daniel Fradl

Quang P Lam

Andrew Wai Lee

Daniel Espinosa

Senthil Krishnapillai

Sarah Ann Russell

Brad Thomas Dransfield

Forest Patton

Ehud Eyal

David F Chiu

Alexander James Karp

Derek Patton

Joe Owen

Bryan Whitmarsh

Noa Falk

David Vejtasa

Stanley D Morse

David E Sabo

Daniel P Fradl

Some examples relate to printing apparatuses and methods. In an example, a roller transfers printing fluid to a substrate. In some examples an electrically grounded roller is positioned proximate the electrically charged roller and guides the substrate. In some examples, the roller is an electrically charged roller. In some examples an electric field is applied and its strength is varied based on a dielectric coefficient of the substrate and/or a thickness of the substrate.

Transferring printing fluid to a substrate

A binary ink developer (BID) may include a power supply electrically coupled to an electrode, a developer roller, and a cleaner roller. The BID may also include a controller to determine a level of image ghosting based on a sum of currents at the electrode, the developer roller and the cleaner roller, and instruct the power supply to provide an adjusted voltage to the cleaner roller in response to a determination of the level of image ghosting.

Binary ink developers

An electrophotographic printer includes a charge roller in charge-transferring relation to a photoconductive imaging portion. The printer may determine an AC voltage setpoint of the charge roller.

Charge roller voltage determination

A print agent supply unit includes: an inlet chamber to distribute print agent within the print agent supply unit; a valve to selectively permit print agent into the inlet chamber, the valve including: a print agent inlet opening; and a valve member to selectively close the print agent inlet opening, the valve member being tapered towards an upstream end of the valve member.

Print agent supply unit valve

A method of balancing current in a developer roller is described. The method includes pulsing voltage to a squeegee roller and a cleaner roller. The pulsed voltage yields a differential voltage at the developer roller after impression. The method also includes pulsing compensating voltage to at least one of the squeegee roller or the cleaner roller to reduce or cancel an accumulated developer current imbalance of the developer roller. The compensating voltage pulses include pulses before or after the impression.

Compensating voltages for electrophotography printing devices

Example implementations provide a method of controlling an ink developer used in electro-photography; the method comprising, following cessation of printing, varying a plurality of voltages associated with movement of ink within the ink developer at temporally disparate times.

Controlling ink developer voltages

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.

Wet null voltages

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.

Developer inlets

In example implementations, an apparatus includes a planar surface, a curved mounting surface and a wiper blade. The curved mounting surface may be coupled adjacent to the planar surface. The wiper blade may be clamped to the planar surface. A bottom of the wiper blade can rest on the curved mounting surface such that a free length of the wiper blade is different at a plurality of points along a width of the wiper blade.

Mounting surfaces for wiper blades

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.

Wet null cycle printing

In one example, a processor readable medium has instructions thereon that, when executed by a processor, cause a system to detect a change in electrical conduction of a liquid moving at an interface between two surfaces and determine a conductivity of the liquid based on the detected change in conduction.

Determining the conductivity of a liquid

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Boise, ID, United States of America

Eric G Nelson