Patent GB-1017666-A (GB)
Title: Electrolytic production of images
IPC: G03G17/02
Filed: 1962-05-15
Abstract: Images are produced by passing through a support in contact with an electrolytic recording layer (see Division D2) containing a reducible compound, a current of such strength and duration as to form in the layer by cathodic action an imagewise pattern containing the reducible compound in the reduced state, and thereafter treating the layer with a reagent which reacts with the unreduced compound to form a coloured compound.  The reducible compound may be contained in a gelatin or polyvinyl alcohol layer on a conductive support or may be applied in solution by a brush to a support having a conductivity pattern.  The reducible compound and the colour forming reagent may both be colourless. Typically the reducible compound may be a coupling compound having a reactive methylene group, such as an a -acylacetanilide, an a -acylaminoacetanilide, a 5-pyrazolone having a reactive 4-position, or a phenol having a reactive 3-position and the colour forming reagent may be an oxidized photographic developer such as a substituted paraphenylene diamine developer. Alternatively the reducible compound may be the oxidized developer and the colour forming reagent may be the coupler. Other suitable colour forming systems are those in which (1) the reducible compound is a diazonium or tetrazonium salt which is electrolytically reducible to a hydrazine and the colour forming reagent is a coupler which couples with the salt to form an azo dye; (2) the reducible compound is p-nitrosodimethylaniline and the reagent is a -naphthol; (3) the reducible compound is 1-p-sulphophenyl-3-methyl-5-pyrazolone and the reagent is a diazonium compound; (4) the reducible compound is MnO2 and the reagent is a leuco dye which reacts with it; or (5) the reducible compound is ferric sulphate and the reagent is potassium ferrocyanide or ammonium thiocyanate.  Preferably the recording layer is washed with water after the electrolysis step to remove the reduced compound if this is water-soluble and the unreduced compound is not.  As described, the imagewise passage of current is effected by means of a conductivity image formed by exposure of a photoconductive material (see Division G2) and the potential applied, e.g. by means of rollers, across this material and the contacting recording material moistened with a solution of NaCl or KCl is between 60 and 80 V., A.C. or D.C.  Reference is also made to the use of other electrical recording systems in which the image is produced electrolytically element by element using one or more scanning electrodes each smaller than an image element.ALSO:1 - Phenyl - 3 - {31 - [211 - (2111 : 4111 - di - t. - amylphenoxy) - 511 - nitro] benzamido} benzamido - 5 - pyrazolone is prepared by adding to 0.39 mole anhydrous sodium acetate dissolved in 850 ml. of 95% acetic acid, 0.2 mole of 1 - phenyl - 3 - (31 - aminobenzamido) - 5 - pyrazolone and 0.23 mole of 2-(21:41-di-tert.-amylphenoxy) - 5 - nitrobenzoyl chloride and stirring the resulting solution for 1 1/2 hours. The product was then separated by filtering and washed successively with acetic acid, water and alcohol, followed by air drying to give a product, intermediate A, of M.P. 153-8 DEG  C.  1 - Phenyl - 3 - {31 - [211 - (2111 : 4111 - di - t. - amylphenoxy) - 511 - amino] benzamido} benzamido - 5 - pyrazolone is prepared by refluxing a boiling solution in acetic acid and alcohol of intermediate A to which metallic iron has been added, filtering off the resulting solution and then pouring the filtrate into cold water. The resulting suspension was then stirred for 15 minutes, filtered, washed with water, pressed to a moist cake and then dissolved in benzene by heating, the aqueous phase drawn off in a separatory funnel and the benzene phase allowed to stand for 3 days.  The crystallized product was then washed successively with benzene and petroleum ether and air-dried giving a compound, intermediate B, of M.P. 234-5 DEG  C.  1 - Phenyl - 3 - {31 - [211 - (2111 : 4111 - diamylphenoxy) - 511 - (21111 - sulphobenzamido) benzamido) benzamido} - 5 - pyrazolone is prepared by adding to boiling xylene undergoing distillation to remove any traces of water 50 gms. of intermediate B and, when this has dissolved, adding to the hot solution 14.3 gms. of freshly prepared o-sulphobenzoic acid anhydride dissolved in hot dry xylene and stirring vigorously for 1 hour while the temperature is held at 90-95 DEG  C. in a steam bath, the reaction mixture thereafter being cooled to room temperature, filtered, washed with dry xylene and dry ethyl ether, and air-dried at 50-60 DEG C., yielding a fine white powder.  1 -Hydroxy - 2 - N - {21 - methoxy - 41 - [X11 -chlorosulphonyl - 311 - (4111 - tert.-amylphenoxy) - benzamido] phenyl} naphthamide is prepared by adding, with stirring, to a glacial acetic acid solution containing 0.04 mole anhydrous sodium acetate, 0.01 mole of 1-hydroxy-2-N-(41-amino-21 - methoxyphenyl) naphthamide hydrochloride and, after stirring for 1 1/2 hours, adding to the resulting slurry 0.125 mole of X-chlorosulphonyl - 3 - (41 - tert. - amylphenoxy) benzoyl chloride dissolved in acetic acid, and after stirring, heating to 50 DEG  C., stirred for 1/2 hour, and allowed to cool. The mixture was then filtered and the filtrate added with stirring to water, forming a white solid which was filtered by suction, washed, dried, redissolved in ether and the resulting solution decolorized with charcoal, filtered and concentrated by heating.  The resulting colourless syrup was then stirred with methanol, filtered, washed successively with methanol and petroleum ether giving a crystalline compound of M.P. 110-130 DEG  C.ALSO:An electrolytic recording material comprises a conducting support of paper which may be baryta coated or sized with gelatin a gelatin or polyvinyl alcohol layer containing a conducting salt such as potassium or sodium chloride, a humectant such as glycerol, formaldehyde and an electrolytically (cathodically) reducible compound which in its unreduced state form a coloured compound when treated with an appropriate colour-forming reagent. Both the reducible compound and the reagent may be colourless, and conductivity may be improved by moistening the material with a solution of a conducting salt such as sodium or potassium chloride and the colloid layer may contain a wetting agent. Typically the reducible compound may be a coupling compound having a reactive methylene group, such as an a -acylacetanilide, an a -acylaminoacetanilide, a 5-pyrazolone having a reactive 4-position, or a phenol having a reactive 3-position and the colour-forming reagent may be an oxidized photographic developer, such as a substituted paraphenylene diamine developer. Alternatively the reducible compound may be the oxidized developer and the colour-forming reagent may be the coupler.  Other suitable colour forming systems are those in which (1) the reducible compound is a diazonium or tetrazonium salt which is electrolytically reducible to a hydrazine and the colour-forming reagent is a coupler which couples with the salt to yield an azo dye; (2) the reducible compound is p-nitrosodimethylaniline and the reagent is a -naphthol; (3) the reducible compound is 1-p-sulphophenyl-3-methyl-5-pyrazolone and the reagent is a diazonium compound; (4) the reducible compound is MnO2 derived from KMnO4 and the reagent is a leuco dye which reacts with it; or (5) the reducible compound is ferric sulphate and the reagent is potassium ferrocyanide or ammonium thiocyanate. With systems (4) and (5), a separate conducting salt is not included in the colloid layer.  Preferably the recording layer is washed with water after the electrolysis step to remove the reduced compound if this is water soluble and the unreduced compound is not.