A mandrel for use in a printing apparatus includes a substantially cylindrical mandrel shaft and plastic expansion rings that are slidably and coaxially mounted on the mandrel shaft. The mandrel also includes a locking assembly including a fixed stop ring and a single locking ring that is axially movably mounted on the mandrel shaft. The expansion rings are positioned between the stop ring and the locking ring. In the unlocked position of the locking ring the expansion rings are in a released state in which the axial compression and the radial expansion of the expansion rings are smaller than in a locked position of the locking ring. A printing cylinder sleeve can be fixedly connected to the mandrel by bringing the expansion rings in the radially expanded state. When the printing cylinder sleeve has to be exchanged, this is feasible when the expansion rings are in the released state.

A mandrel for use in a printing apparatus includes a substantially cylindrical mandrel shaft and plastic expansion rings that are slidably and coaxially mounted on the mandrel shaft. The mandrel also includes a locking assembly including a fixed stop ring and a single locking ring that is axially movably mounted on the mandrel shaft. The expansion rings are positioned between the stop ring and the locking ring. In the unlocked position of the locking ring the expansion rings are in a released state in which the axial compression and the radial expansion of the expansion rings are smaller than in a locked position of the locking ring. A printing cylinder sleeve can be fixedly connected to the mandrel by bringing the expansion rings in the radially expanded state. When the printing cylinder sleeve has to be exchanged, this is feasible when the expansion rings are in the released state.

A compliant surface is created with micron scale dimples above an electrically biased conductive layer. The dimpled surface is charged to a desired charge density and filled partially with fountain solution in either order. Then the compliant surface is brought adjacent a charge-retentive surface bearing an electrostatic charged pattern. In examples the fountain solution charge is repelled in the downward directed field under discharged (or uncharged) regions of the charge-retentive surface and is attracted to the surface at the electrostatic charged pattern in the regions of charged pixels. Electrostatic forces drag the fountain solution from the dimples to the charged pixel surface and away from the discharged pixel regions. Electrophoretic forces cause the fountain solution within the dimples to flow up to the charge image and wet the surface. A desired volume is controlled by varying parameters such as nip pressure.

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 compliant surface is created with micron scale dimples above an electrically biased conductive layer. The dimpled surface is charged to a desired charge density and filled partially with fountain solution in either order. Then the compliant surface is brought adjacent a charge-retentive surface bearing an electrostatic charged pattern. In examples the fountain solution charge is repelled in the downward directed field under discharged (or uncharged) regions of the charge-retentive surface and is attracted to the surface at the electrostatic charged pattern in the regions of charged pixels. Electrostatic forces drag the fountain solution from the dimples to the charged pixel surface and away from the discharged pixel regions. Electrophoretic forces cause the fountain solution within the dimples to flow up to the charge image and wet the surface. A desired volume is controlled by varying parameters such as nip pressure.

A compliant surface is created with micron scale dimples above an electrically biased conductive layer. The dimpled surface is charged to a desired charge density and filled partially with fountain solution in either order. Then the compliant surface is brought adjacent a charge-retentive surface bearing an electrostatic charged pattern. In examples the fountain solution charge is repelled in the downward directed field under discharged (or uncharged) regions of the charge-retentive surface and is attracted to the surface at the electrostatic charged pattern in the regions of charged pixels. Electrostatic forces drag the fountain solution from the dimples to the charged pixel surface and away from the discharged pixel regions. Electrophoretic forces cause the fountain solution within the dimples to flow up to the charge image and wet the surface. A desired volume is controlled by varying parameters such as nip pressure.

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.

The invention relates to a roll take-up device (110) designed for a) taking up a sheetlike composite (101), and b) rolling up or unrolling or both rolling up and unrolling a roll (102) of the sheetlike composite (101); i) a carrier layer (304), ii) a barrier layer (306) and iii) an inner polymer layer (308); wherein, in the roll (102), at least 10 laminas of the sheetlike composite (101) are overlaid on one another from the inside outwards or vice versa; wherein the laminas respectively have the series of layers (304, 306, 308); wherein one layer (306) of the series of layers of the sheetlike composite (101) is an electrically conductive layer.

In a digital inking system having an anilox member that carries a patterned metered layer of ink to a digital imaging member, and a doctor blade that removes excess ink from the surface of the anilox member resulting in the patterned metered layer, an overfill form roller in rolling contact with the anilox member adds an overcoat layer of ink on the patterned metered layer for transfer of both layers of ink to the digital imaging member. The overcoat layer of ink uniformly covers all regions of the anilox member and the mattered metered layer of ink, including lands of the anilox cell walls to make the combined layers of ink pattern-free.

In a digital inking system having an anilox member that carries a patterned metered layer of ink to a digital imaging member, and a doctor blade that removes excess ink from the surface of the anilox member resulting in the patterned metered layer, an overfill form roller in rolling contact with the anilox member adds an overcoat layer of ink on the patterned metered layer for transfer of both layers of ink to the digital imaging member. The overcoat layer of ink uniformly covers all regions of the anilox member and the mattered metered layer of ink, including lands of the anilox cell walls to make the combined layers of ink pattern-free.