Duplicating systems
AssigneeLamson Industries Limited
InventorsDavid John Neale, Stanford Frederick Dawney
Life of this patent
Estimating the term…
Abstract
A process for hectographic duplicating, and hectographic copy paper therefor, are disclosed. The hectographic copy paper is formed by applying a coating of a film-forming vehicle and a colourless dyestuff precursor which is sodium p-carboxy phenyl leucauramine, sodium p-sulphophenyl leucauramine of Michler's hydrol methyl ether. The sheets are used to type or otherwise form an imaged hectographic master sheet, which is then contacted with hectographic copy sheets moistened with a spirit duplicating fluid, with the dyestuff precursors converted into dyestuffs on the hectographic copy sheets.
Claims24
In a process for hectographic duplicating, said process comprising the steps of
- a. forming hectographic transfer sheets by applying a coating of a composition comprising at least 20% by weight of at least one at least substantially colorless dyestuff precursor, and a film-forming vehicle therefor, at a dry coated weight of about 5 to about 40 gsm, to a base web.
- b. thereafter contacting said coating with a hectographic sheet, and transferring selected portions of said coating to the hectographic sheet by the application of pressure, to form an imaged hectographic master and,
- c. thereafter successively contacting the imaged hectographic master with a plurality of hectographic copy sheets moistened with an ethanol spirit duplicating fluid, and converting the dyestuff precursor into the dyestuff to form legible copies,
- the improvement comprising using, as said dyestuff precursor, a leucauramine dyestuff precursor of the formula ##SPC5##
- wherein R is methoxy, sodium p-carboxyphenylamino or sodium-p-sulphophenylamino.
In a process for hectographic duplicating, said process comprising the steps of
- a. forming hectographic transfer sheets by applying a coating of a composition comprising at least 20% by weight of at least one at least substantially colorless dyestuff precursor, and a film-forming vehicle therefor, at a dry coated weight of about 5 to about 40 gsm, to a base web,
- b. thereafter contacting said coating with a hectographic sheet, and transferring selected portions of said coating to the hectographic sheet by the application of pressure, to form an imaged hectographic master and,
- c. thereafter successively contacting the imaged hectographic master with a plurality of hectographic copy sheets moistened with an ethanol spirit duplicating fluid, and converting the dyestuff precursor into the dyestuff to form legible copies,
- the improvement comprising using, as said dyestuff precursor, sodium p-sulphophenyl leucauramine.
A hectographic transfer sheet consisting essentially of a base web having a coating on at least one side thereof, said coating comprising at least 15% by weight of at least one dyestuff precursor of the formula ##SPC6##
- wherein R is methoxy, sodium p-carboxyphenylamino or sodium-p-sulphophenylamino, and a film-forming vehicle therefor;
- wherein the coating is at a dry coated weight of about 5 to about 40 gsm.
A hectographic transfer sheet consisting essentially of a base web having a coating on at least one side thereof, said coating comprising at least 15% by weight of sodium p-sulphophenyl leucauramine, and a film-forming vehicle therefor, wherein the coating is at a dry coated weight of about 5 to about 40 gsm.
Dependencies are inferred from the claim text.