Method for inking printing plates

A method for applying a controlled balance of ink and dampening fluid to a lithographic printing plate at a fluid transfer area between the lithographic printing plate and an applicator roller, comprising the steps of

• (A) forming a continuous uniform ink layer having a desired thickness on the applicator roller for the conveyance into said fluid transfer area and onto said lithographic plate, including the steps of
• (1) depositing an excess of ink on said applicator roller,
• (2) providing a metering roller adjacent to said applicator roller,
• (3) metering the ink deposited on said applicator roller by forming a fluid metering nip between said applicator roller and said metering roller, said applicator roller and said metering roller cooperating to form a reservoir for said excess of ink,
• (4) supporting said applicator roller and said metering roller in a preselected pressure indented relation to form said nip,
• (5) rotating said applicator roller and said metering roller such that adjacent surfaces move in opposite directions at said nip and at a preselected speed differential,
• (6) controlling the thickness of said continuous uniform ink layer formed on said applicator roller by
• (a) forming a continuous uninterrupted uniform ink layer on the metering roller by placing a doctor blade in cooperation with said metering roller,
• (b) controlling the physical properties of said layer of ink on said metering roller by controlling temperature of the ink so as to provide a continuous uniform metering surface of ink having uniform physical properties at the said metering nip which upon contact with the ink on said applicator roller will remove all but a uniform layer of ink of a desired thickness from said applicator roller,
• (c) adjusting said doctor blade for thus adjusting the thickness of said ink layer conveyed by said metering roller into said metering nip in order to create and maintain a desired precision controlled thickness in the said layer of ink conveyed by said applicator roller into the fluid transfer area,
• (d) adjusting the relative surface speeds of said metering roller and said applicator roller,
• (e) adjusting the pressure between said metering roller and said applicator roller,
• (B) applying dampening fluid in a variable amount in accordance with the thickness of the ink layer formed in step (A) to the said layer of ink conveyed by said applicator roller at a point between the fluid metering nip and said fluid transfer area to form a controlled balance of ink and dampening fluid conveyed by said applicator roller into said transfer area without introducing dampening fluid into said metering nip.