Black oxide lithographic ink metering roller

Claim 2

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 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 3 O 4 .

Claim 3

An ink metering roller as defined in claim 1 wherein the oxygen to iron ratio of the metal oxide is less than the stoichiometric ratio of 1.33 for Fe 3 O 4 .

Claim 4

An ink metering roller as defined in claim 2 wherein the atomic oxygen to iron ratio of the metal oxide on the surface of said roll ranges from about 1.2 to 1.3.

Claim 5

An ink metering roller as defined in claim 3 wherein the atomic oxygen to iron ratio decreases in the direction inwardly from the surface of said roller.

Claim 6

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 3 O 4 .

Claim 7

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 3 O 4 .

Claim 8

The process as defined in claim 5 wherein said oxidizing treatment is effected by immersing the roll into an oxidizing oil bath at a temperature of from about 300° to 450° F.

Claim 9

The process as defined in claim 5 wherein said roll is nitrided for a time to form a case of not less than about 3 mils thickness and not less than about R C 55 hardness.

Claim 10

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.

Claim 11

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.