Hewlett-packard Development Company, L.P.

Hp Indigo B.v.

Lavi Cohen

Asaf Shoshani

Michael Vinokur

Eric G Nelson

Doron Schlumm

Ido Finkelman

Shachar Berger

Meir Grinstein

Minedys Macias Guzman

Alon Froom

Shimi Nakash

Sasha Zilbershtein

Alex Feygelman

Michael Plotkin

Avi Barazani

Matan Schneider

Israel Katz

Sagie Shanun

Amit Porat

Yossi Yaacobov

Yaniv Yona

Sergey Guralnik

Shai Rahamim

Roman Katz

Yonni Hartstein

Assaf Barel

Eyal Rosenwein

Hanan Sachs

Eyal Elbaz

Tal Shani

Elad Alfo

Hay Arbeli

Tomer Bunker

Yulia Haddad

Zeharia Levi

Disclosed is a liquid electrophotographic printing apparatus that comprises a developer roller, a cleaning member to contact the developer roller with a contact force and a force adjustment arrangement to adjust the contact force.

Force adjustment arrangement

According to an example, a photoconductive drum support comprises a receiving body to receive a photoconductive drum, a rear cup coupled to a first end of the receiving body, a locking member rotatably coupled to a projecting portion of the receiving body, and a front cup positioned to contact a second end of the receiving body. The locking member is movable between an unlocked position in which the front cup is movable along the projecting portion and a locked position in which the locking member is positioned to fix the front cup and the rear cup at a predetermined distance.

Photoconductive drum supports

A printing drum for a liquid electrophotographic printing system which comprises a photosensitive surface and a heating device mounted to the printing drum. The heating device heats the photosensitive surface of the printing drum to a predetermined temperature.

Heating for a printing drum

A print apparatus is disclosed. In an example, the print apparatus comprises: a photoconductive surface to receive a latent image representative of an image to be printed onto a printable substrate; a plurality of print components, each print component having a surface movable relative to the photoconductive surface, wherein a current or voltage is to be applied between the print component surface and the photoconductive surface; and processing circuitry to: measure a current or voltage between each print component surface and the photoconductive surface; responsive to detecting a deviation in the measured current or voltage from a reference current or voltage in respect of any of the plurality of print components, determine that there exists a defect associated with the photoconductive surface; and determine, based on the amount of deviation of the measured current or voltage from the reference current or voltage, an indication of the size of the defect.

Determining the existence of defects in print apparatuses

In an example, a printing apparatus may include, a rotatable shaft, a removable drum mounted on the shaft and a fixing element to fixedly couple the removable drum to the shaft, so that the removable drum is to rotate with the shaft. The printing apparatus may also include a heater, a printing apparatus satellite component located adjacent to the removable drum and engageable with the removable drum and a controller. The controller may be to receive a command to prepare the removable drum for removal; and in response, control the shaft to rotate the removable drum; control the heater to heat the removable drum while it rotates; and control the printing apparatus to engage the satellite component of the printing apparatus with the removable drum while it rotates.

Printer drum removal preparation

A positioning device to control the position of a print agent applicator comprises a mount to support a print agent applicator at a load point on the mount; an actuator coupled to the mount to apply a driving force at an actuation point on the mount; and a guide mechanism to guide the mount and supported print agent applicator, under the driving force, to translate along a predetermined path towards a printing drum to form an engaging contact between the print agent applicator and the printing drum.

Print agent applicator positioning devices

In an example of the disclosure, an imaging oil is applied upon a photoconductor surface. An element is brought into contact with the imaging oil at the photoconductor surface. The element has a first refractive index that is within a predefined tolerance of a second refractive index of the imaging oil. The photoconductor surface is exposed to light emitted by a writing component. The light passes through the element and the imaging oil.

Reducing reflectance variances of photoconductive surfaces

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.

Liquid electro-photographic printing transfer

In an example, a method includes rotating a print apparatus component to be cleaned about a first rotational axis. A cleaning element having a cleaning surface in contact with the print apparatus component may be driven such that the cleaning surface has a component of motion which is parallel to the first rotational axis in a contact region. A relative velocity of the cleaning element and the print apparatus component may be varied during a cleaning operation.

Cleaning elements for print apparatus

In one example of the disclosure, a developer system includes a housing and a developer roller. A first electrode and a second electrode are disposed in the housing, the first and second electrodes to create an electrical charge to cause transfer of printing fluid to a developer roller surface. The developer roller is rotatably connected to the housing. The developer includes a surface, a bearing to support and enable rotation of an axle attached to the developer roller, and a plurality of stop pins. The plurality of stop pins are connected to the housing. The stop pins are to support the bearings and to establish target distances between the developer roller surface and the first electrode and second electrodes.

Establishing distances between developer roller surfaces and electrodes

A print apparatus component to be cleaned is rotated about a rotational axis. A cleaning element having a cleaning surface in contact with the print apparatus component is rotated. The cleaning element is oscillated in a direction parallel to the rotational axis. Rotation and oscillation of the cleaning element are varied according to a predetermined function to remove a residue from the print apparatus component.

Cleaning of print apparatus components with rotation and oscillation

A method of printing images in a liquid electrophotographic printer is provided. In an example, the method includes measuring at least one current associated with an image development unit of the liquid electrophotographic printer. A first time at which a peak occurs in the measured current is determined; the first time indicates that a printing substance is transferred from a point on a developer roller of the image development unit to a photo imaging member of the liquid electrophotographic printer at a first location within the image development unit. A second time at which said point on the developer roller is expected to contact the cleaner roller within the image development unit is calculated and, at the second time, a voltage applied to the cleaner roller is controlled to reduce the potential difference between the cleaner roller and the developer roller.

Voltage control in a liquid electrophotographic printer

In an example, a method includes collecting () print agent from a print agent reservoir to form a print agent layer on a first print agent transfer member (). The print agent layer may be transferred () directly from the first print agent transfer member to a second print agent transfer member (), where the print agent layer may be heated (). The print agent layer may be applied () directly from the second print agent transfer member to a substrate.

Transferring print agent using first and second transfer members

In an example, a cleaning station comprises a wiper blade to scrape cleaning fluid across a surface of a component of a print apparatus. A suction pump is to remove a cleaning fluid from a surface of the component of the print apparatus. A sensor is to determine the thickness of cleaning fluid on a surface of the component of the print apparatus. A controller is to vary a suction pressure of the suction pump based on measurements of the sensor.

Determining cleaning fluid thickness

A developer for a printer for printing to a substrate; the developer comprising a plurality of rollers operable to influence forming an image; the plurality of rollers comprising a developer roller for bearing printing liquid for forming the image and a squeegee roller for cooperating with the developer roller to influence the printing liquid on the developer roller, the squeegee roller being operable, via a brake, to stop rotating relative to the developer roller to influence the printing liquid on the developer roller.

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Ness Ziona, Israel

Lavi Cohen