An optical light reflectance measurement system above an imaging member surface measures fountain solution surface light reflectance interference on reflective substrate portions of the imaging member surface in real-time during a printing operation. The measured light reflectance interference corresponds to a thickness of the fountain solution layer and may be used in a feedback loop to actively control fountain solution layer thickness by adjusting the volumetric feed rate of fountain solution added onto the imaging member surface during a printing operation to reach a desired uniform thickness for the printing. This fountain solution monitoring system may be fully automated.

An image based correction system compensates for the image quality artifacts induced by thermal ghosting on evolving imaging member surfaces. With thermal ghosting directly tied to previous image content, a feed forward system determines thermal ghosting artifacts based on images previously rendered and generates an open loop gray-level correction to a current image that mitigates undesirable ghosting. For example, the correction system compensates for the thermal ghosting by making the current image “lighter” in areas that will be imaged onto warmer blanket regions, thereby cancelling out TRC differences between different temperature regions. A temperature sensor is used to measure the temperature of the imaging blanket due to the stresses induced by the image. This data is used to learn the parameters of the temperature model periodically during operation, and used in subsequent corrections to mitigate thermal ghosting in spite of changes in blanket properties over use and time.

Disclosed herein are methods for an ink-based digital printing system, comprising providing an imaging member a reimageable surface layer disposed on a structural mounting layer, the reimageable surface layer comprising a fluorosilicone elastomer and an infrared-absorbing filler comprising carbon black, and a plurality of surface defects on the reimageable surface layer, wherein the surface defects comprises carbon black exposed through the fluorosilicone elastomer of the reimageable surface layer. The method also comprises applying a coating of rejuvenating oil comprising an amino-functional organopolysiloxane to the reimageable surface layer, whereby at least a portion of the plurality of surface defects are coated by the amino-functional organopolysiloxane, thereby rejuvenating the imaging member.

Disclosed herein are methods for an ink-based digital printing system, comprising providing an imaging member a reimageable surface layer disposed on a structural mounting layer, the reimageable surface layer comprising a fluorosilicone elastomer and an infrared-absorbing filler comprising carbon black, and a plurality of surface defects on the reimageable surface layer, wherein the surface defects comprises carbon black exposed through the fluorosilicone elastomer of the reimageable surface layer. The method also comprises applying a coating of rejuvenating oil comprising an amino-functional organopolysiloxane to the reimageable surface layer, whereby at least a portion of the plurality of surface defects are coated by the amino-functional organopolysiloxane, thereby rejuvenating the imaging member.

A method for ink-based digital printing includes applying a uniform layer of dampening fluid to a surface of an imaging member; laser patterning the dampening fluid layer by selectively removing portions of the dampening fluid according to digital image data; and inking the laser-patterned dampening fluid layer on the imaging member surface with a aqueous heterogeneous ink to form an ink image, wherein the aqueous heterogeneous ink self-coalesces before the ink is transferred from the imaging member surface.

A method for ink-based digital printing includes applying a uniform layer of dampening fluid to a surface of an imaging member; laser patterning the dampening fluid layer by selectively removing portions of the dampening fluid according to digital image data; and inking the laser-patterned dampening fluid layer on the imaging member surface with a aqueous heterogeneous ink to form an ink image, wherein the aqueous heterogeneous ink self-coalesces before the ink is transferred from the imaging member surface.

A heating circuit having an array of switching heating elements (e.g., field effect transistors, thin film transistors) provides a transient heat pattern over a surface (e.g., substrate, imaging member surface, transfer roll surface) moving relative to the heating circuit, to produce a pixelated heat image and heat a target pattern on the surface. Heat is generated by current flow in the heating elements, and the power developed by the heating circuit is the product of source-drain voltage and current in the channel. Digital addressing may accomplished by matrix addressing the array. Current may be supplied along data address lines by an external voltage controlled by digital electronics understood by a skilled artisan to provide the desired heat at a respective heating element pixels addressed by a specific gate line. The circuit may include a current return line that may be low resistance, for example, by using a 2-dimensional mesh.

According to aspects of the embodiments, there is provided a method of measuring the amount of fountain solution employed in a digital offset lithography printing system. Fountain solution thickness is measured using a glass roll at a lower temperature than the fountain solution. The lower temperature causes the fountain solution to undergo a change in state and in a solid state the fountain solution crystalizes and changes roll opacity with the thickness of the film. When radiated with a light source the opacity is continuously measured through the surface of the roller. The thickness of the crystallized fountain solution can then be determined via the opacity level increase by the crystallization and the impact to the opacity on the glass roll.

A formative surface having a conductive base covered with a dielectric and oleophobic/hydrophobic surface layer is created with defined pits to grow micro-puddles of a defined volume. The formative surface is brought into close proximity with a charge retentive surface carrying a charge image. Fountain solution vapor nucleates and grows preferentially on the base of the pits as micro-puddle droplets. The puddles are charged and extracted from the surface to provide a fog of charged droplets of narrow volume and charge distribution. The charged droplets are attracted and repelled respectively from the charged and discharged image regions of the charge retentive surface, thus developing the charged image into a fountain solution latent image. The developed latent image is then brought into contact with a transfer member blanket and split, thus creating on the blanket a fountain solution latent image ready for inking.

A formative surface having a conductive base covered with a dielectric and oleophobic/hydrophobic surface layer is created with defined pits to grow micro-puddles of a defined volume. The formative surface is brought into close proximity with a charge retentive surface carrying a charge image. Fountain solution vapor nucleates and grows preferentially on the base of the pits as micro-puddle droplets. The puddles are charged and extracted from the surface to provide a fog of charged droplets of narrow volume and charge distribution. The charged droplets are attracted and repelled respectively from the charged and discharged image regions of the charge retentive surface, thus developing the charged image into a fountain solution latent image. The developed latent image is then brought into contact with a transfer member blanket and split, thus creating on the blanket a fountain solution latent image ready for inking.