Dampening fluid removal device

A method of inking a lithographic printing plate wherein dampening fluid having a viscosity of less than one poise, is applied to the printing plate to render hydrophilic, non-image areas, on the printing plate ink rejecting;

• and wherein ink, having a viscosity significantly greater than 10 poise, is applied by an inking roller, having a resilient surface, to oleophilic, image, areas on the printing plate of an inking nip, the improvement comprising the steps of:
• positioning a doctor blade having a leading edge and a trailing edge in pressure indented relation with the resilient surface on a single inking form roller to engage ink and dampening fluid on the portion of the surface of the inking roller which has applied ink to the printing plate and before fresh ink is applied to the portion of the inking roller surface such that dampening fluid on the ink, carried by the resilient roller surface, impinges against a substantially flat metering surface on said doctor blade adjacent to the edge;
• urging both the metering edge and the trailing edge in a direction generally radially of the single form roller to urge both the metering edge and the trailing edge into indented relation with the roller surface;
• resiliently supporting the doctor blade in a direction radially of the form roller to permit movement of the metering edge relative to the axis of the form roller;
• and supporting said metering edge to prevent movement of the metering edge in a direction tangent to the single form roller;
• positioning the metering surface of the doctor blade at an angle relative to a line tangent to the roller surface to remove fluid having a viscosity less than a predetermined viscosity from the surface of the inking roller and to leave fluid having a viscosity greater than the predetermined viscosity on the surface of the inking roller;
• and positioning a metering member having a metering edge and a trailing edge in pressure indented relation with the resilient surface on said single inking form roller such that ink carried by the resilient roller surface impinges against a substantially flat metering surface on said metering member adjacent to the metering edge;
• urging both the metering edge and the trailing edge in a direction generally radially of the form roller to urge both the metering edge and the trailing edge into indented relation with the resilient roller surface;
• resiliently supporting the metering member in a direction radially of the form roller to permit movement of the metering edge relative to the axis of the form roller;
• supporting said metering edge to prevent movement of the metering edge in a direction tangent to the form roller;
• applying fresh ink having a viscosity greater than said predetermined viscosity to the portion of the inker roller surface from which fluid having a viscosity less than said predetermined viscosity has been removed, wherein the dampening fluid is metered between a resilient surfaced roller and a hard hydrophilic surfaced roller;
• rotating the hard hydrophilic surfaced roller at a surface speed which is different from the surface speed of the inking form roller to transfer dampening fluid to ink on the form roller;
• and rotating the form roller to apply dampening fluid and ink to the printing plate.

A method of inking a lithographic printing plate wherein dampening fluid having a viscosity of less than one poise, is applied to the printing plate to render hydrophilic, non-image areas, on the printing plate ink rejecting;

• and wherein ink, having a viscosity significantly greater than the viscosity of dampening fluid, is applied by an inking roller, having a resilient surface, to oleophilic, image, areas on the printing plate of an inking nip, the improvement comprising the steps of:
• positioning a metering member having a metering edge and a trailing edge in pressure indented relation with the resilient surface on said inking form roller such that ink carried by the resilient roller surface impinges against a substantially flat metering surface on said metering member adjacent to the metering edge;
• urging both the metering edge and the trailing edge in a direction generally radially of the form roller to urge both the metering edge and the trailing edge into indented relation with the resilient roller surface;
• resiliently supporting the metering member in a direction radially of the form roller to permit movement of the metering edge relative to the axis of the form roller;
• supporting said metering edge to prevent movement of the metering edge in a direction tangent to the form roller;
• applying dampening fluid to the metered film of fresh ink;
• rotating the form roller to apply ink and dampening fluid to the printing plate;
• positioning a doctor blade in pressure indented relation with the resilient surface of the inking form roller to engage ink and dampening fluid on the portion of the surface of the inking roller which has applied ink to the printing plate and before fresh ink is applied to the portion of the inking form roller surface;
• positioning a flat metering surface of the doctor blade at an angle relative to a line tangent to the roller surface to remove fluid having a viscosity less than a predetermined viscosity from the surface of the inking form roller and to leave fluid having a viscosity greater than the predetermined viscosity on the surface of the inking form roller;
• and applying fresh ink having a viscosity greater than said predetermined viscosity to the portion of the inker form roller surface from which fluid having a viscosity less than said predetermined viscosity has been removed by the doctor blade.