Method and apparatus for inking printing plates
AssigneeDahlgren Manufacturing Company
InventorsHarold P. Dahlgren, Harvey W. Dahlgren
Life of this patent
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Abstract
The inker and inking method include forming a metering nip between the ink applicator roller of a printing press to which an excess of ink has been previously applied and a metering unit. A uniform film of ink is then formed on the surface of the metering unit and the physical properties of this film of ink are subsequently varied and controlled so that when this film contacts the ink on the applicator roller at the metering nip, a uniform layer of ink of a desired thickness is created and maintained on the applicator roller as it leaves the nip.
Claims16
A method for inking the rotating applicator roller of a printing press so as to form thereon a uniform layer of ink of controllable thickness and to remove from the applicator roller any undesirable ink accumulations and image forming variations in the inked surface of the applicator roller that supplies ink for a printing member of said printing press, comprising the steps of
- a. applying to a surface of said applicator roller which has previously supplied ink for said printing member during the rotational cycle of the applicator roller a volume of ink which exceeds the volume of ink to be next supplied for said printing member by that surface of the applicator roller and which is sufficient to destroy any image forming variations in the inked surface of said applicator roller;
- b. forming a metering nip between said applicator roller and a metering unit;
- c. initially forming on said metering unit at a point removed from said metering nip a substantially uniform, uninterrupted film of ink having a controllable film thickness;
- d. contacting at the metering nip the ink on the surface of said applicator roller which has been provided with said excess of ink with said substantially uniform, uninterrupted film of ink supported on the metering unit and moving at a speed different from the speed of said applicator roller surface to cause said film of ink to shear ink from said applicator roller,
- e. varying the physical properties of said film of ink on the metering unit to provide a continuous uniform metering surface of ink having uniform physical properties at the metering nip which upon contact with the ink on the applicator roller will remove all but a uniform layer of ink of a desired thickness from said applicator roller;
- and
- f. upon the occurrence of changing conditions which cause variation in the desired thickness of the layer of ink on the surface of the applicator roller, adjusting one or more of the physical properties including thickness, viscosity or temperature of the film of ink moving from the point of formation thereof to the metering nip to maintain said uniform physical properties of the metering surface of ink at the metering nip to cause said metering surface of ink to maintain the uniform layer of ink of the desired thickness on the surface of said applicator roller as said applicator roller surface moves away from said metering surface of ink.
In an inker for applying ink to a plate secured to a plate cylinder rotatably supported between the spaced side frames of a printing press, inker side frames supported by the press side frames;
- first and second hanger members;
- means to pivotally secure said first and second hanger members to said inker side frames;
- means to rotate said first and second hanger members about said means to pivotally secure said hanger members to said inker side frames;
- an off-stop secured to said inker side frames engageable with at least one of said hanger members to limit rotation of said hanger members in a first direction;
- an on-stop secured to said inker side frames and engageable with at least one of said hanger members to limit rotation of said hanger members in a second direction;
- and applicator roller having a resilient ink-receptive surface;
- means to rotatably secure said applicator roller between said hanger members;
- a metering roller having an ink-receptive surface;
- means to rotatably secure said metering roller between said hanger members such that said metering roller is movable between a first position wherein surfaces of said metering roller and applicator roller are in pressure indented relation and a second position wherein sufaces of said metering roller and applicator roller are separated;
- a doctor blade;
- means to position said doctor blade adjacent the surface of said metering roller such that when in use a continuous unbroken film of ink is maintained on the surface of the metering roller;
- means to drive said metering roller and applicator roller such that adjacent surfaces move in opposite directions;
- and means to control the temperature of the surface of the metering roller.
Dependencies are inferred from the claim text.