| 摘要 |
In a method of duplicating, a master sheet is inscribed imagewise with a first chemical then applied under heat to a copy sheet treated with a second chemical which reacts with the first to produce a visual coloured image on the copy sheet. In the described embodiments the original is imaged in a typewriter, a specially prepared ribbon being used which consists of the usual support tape carrying a composition of ink and an appropriate chemical "A." The nature of this chemical depends upon the chemical carried by the copy sheets but, as an example, chemical "A" is rubeanic acid whilst chemical "B"-that carried by the copy sheets-comprises nickel salts dissolved in water or alcohol to which an amine has been added. A modified ribbon is described in which one half is coated or permeated with the ink and chemical "A" whilst the other half is coated with a chalk-like material for correcting errors. Following is a listing of suitable materials for Chemical A with corresponding reaction partners Chemical B: ..A .1..Pyrocatechol .2..Aniline .3..Dithiooxamide (rubeanic acid) ..N-dimethyl-dithiooxamide ..N,N1-bis-(2-hydroethyl) dithiooxamide ..N,N1-bis-(carboxy-methyl) dithiooxamide ..Other dithiooxamide derivatives .4..Hydrazine ..Pyrogallol ..N-(p-Hydroxyphenyl) glycine ..Hydroxylamine ..Diaminophenol hydrochloride ..p-Methylaminophenol sulphate ..Dichlorohydroquinone ..Thiourea ..Chlorohydroquinone ..Bromohydroquinone ..Gallic acid .5..Ammonia salts ..Ammonium benzoate ..Ammonium acetate ..Ammonium carbonate ..B .1..Iron salts .2..Vanadium salts ..Potassium dichromate .3..Copper salts ..Nickel salts ..Cobalt salts .4..Silver salts .5..Organic diazonium salts ..and couples |
