Browse Prior Art Database

IMPROVED ELECTROSTATIC PRINTING INKS

IP.com Disclosure Number: IPCOM000023498D
Original Publication Date: 1977-Dec-31
Included in the Prior Art Database: 2004-Mar-31
Document File: 4 page(s) / 554K

Publishing Venue

Xerox Disclosure Journal

Abstract

Improved inks for electrostatic printing comprise the fol-lowing ingredients (concentrations expressed by weight) pigment and/or dye 5-20% nitrogen-containing compound 0.1-5% zinc-containing compound 0-5%

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XEROX DISCLOSURE JOURNAL

IMPROVED ELECTROSTATIC Proposed Classification

PRINTING INKS U.S. Cl. 252/62.1
David A. Allen mt. Cl. G03g 9/00
Chin H. Lu

Improved inks for electrostatic printing comprise the fol-

lowing ingredients (concentrations expressed by weight)

pigment and/or dye 5-20%

nitrogen-containing
compound 0.1-5%

zinc-containing
compound 0-5%

cyclized rubber 5-25%

oxygen-containing
low vapor pressure
organic liquid 5-40%

low vapor pressure
hydrocarbon solvent 5-85%

The pigments and/or dyes may be any of the well-known ink or
liquid developer colorants and include carbon blacks, phospho-
tungstates, phosphomolybdates, alkali blue, azo pigments,
nigrosine dyestuffs and the like, The nitrogen-containing
organic compounds or polymers include such materials as the
alkylated polymers of a heterocyclic N-vinyl monomer, e.g.,
alkylated polyvinyl pyrrolidones, lecithin, lecithin mixtures
and the like. The optional zinc-containing organic compounds
or polymers include such materials as zinc resinate, zinc-
calcium resinate, zincated modified rosin, zinc naphthenates
and the like. The cyclized rubbers are well-known rubber base
resins and may be obtained by well-known processes such as
reacting sulfuric acid or sulfonic acid with a rubber; redu-
cing a halogenated rubber to a dehalogenated rubber; heating a
solid rubber or rubber solution to more than 250°C in the
presence of a catalyst, and the like. The oxygen-containing
low vapor pressure (less than about 0.02 mm. Hg at 25°C)
organic liquids include esters, alcohols, ethers, vegetable

Volume 2 Number 6 November/December 1977 77

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IMPROVED ELECTROSTATIC PRINTING INKS (Cont~d)

oils, animal oils and the like. The low vapor pressure
hydrocarbon solvents include any of the well-known inert
hydrocarbon and hydrocarbon petroleum fractions having a vapor
pressure of less than about 0.02 mm. Hg at 25°C, e.g., mineral
oils, hydrocarbon solvents, and the like,

The electrostatic printing inks having these compositions
exhibit fast drying characteristics and produce prints having
high density, low background and excellent rub resistance.

The inks have a low viscosity (about 200 - 1,000 centipoises
at 25°C) and excellent pot life. Upon printing, the inks dry
quickly by absorption into the paper. These printing inks are
particularly useful in the electrostatic printing apparatus
and method described in United States Patent No. 3,084,043
where ink or liquid developer is applied to a latent electro-
static image to be developed by a patterned ink applicator,
e.g., one...