Black oxide lithographic ink metering roller
AssigneeRockwell International Corporation
InventorsThomas A. Fadner, Stanley H. Hycner
Life of this patent
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Abstract
A steel ink metering roller for use in lithographic printing having an engraved surface that has been nitride hardened followed by an oxidizing process that results in a surface with a composition of mainly Fe.sub.3 O.sub.4.
Claims8
An ink metering roller for use in lithographic printing comprising:
- a. an engraved base roller of suitable diameter and length, selected from nitride-hardenable steel;
- b. an outer zone of not less than about 3 mils thickness that is nitride-hardened to an R.sub.c value of not less than about 55;
- c. an outermost microporous iron oxide layer on said outer surface of said steel roller that consists essentially of Fe.sub.3 O.sub.4.
A process for producing an ink metering roller for use in lithographic printing comprising the steps of:
- a. providing a nitride-hardenable steel roll of preselected diameter and surface configuration;
- b. nitriding the roll to a preselected depth to produce a face case of increased hardness and;
- c. oxidizing the nitrided surface of the roll to produce a microporous layer or iron oxide whose composition consists principally of the oxide Fe.sub.3 O.sub.4.
An inking system for use in lithographic printing consisting at least in part of a nitride-hardened steel ink metering roller coextensive with the width of a lithographic printing press system, said metering roller consisting of recesses or cells of appropriate frequency and volume to deliver a uniform and acceptable ink density by means of auxiliary rollers to a substrate being printed by said printing press system, and consisting of land areas between said cells or recesses upon which rests during operation a reverse-angle ink-doctoring blade coextensive with said ink-metering roller, said roller having surfaces that are made oleophilic and hydrophobic by black-oxide treatment of said roller surface.
Dependencies are inferred from the claim text.