| 摘要 |
The Specification describes photoconductive compositions of poly-N-vinyl-carbazole as selfsupporting foils or as layers on supports, for use in electrostatic printing. The compositions may contain one or more of the following:-ddyestuffs, inorganic acids, organic acids (carboxylic, sulphonic or phosphonic), nitrophenols, acid anhydrides, metal and metalloid halides (other than of alkali metals), boron halides, ketones, quinones, aldehydes, other resins, pigments such as zinc oxide or titanium dioxide, and other photoconductive organic substances. Many suitable compounds of the above type are listed. The organic acids, ketones and aldehydes may be aliphatic, carbocyclic or heterocyclic, and may be substituted, e.g. by hydroxy, halogen, nitro, alkoxy, amino or cyano groups. Specified halides are those of aluminium, zinc, iron, tin, arsenic, antimony, magnesium, calcium, strontium, chromium, manganese, cobalt, copper, cerium, thorium, mercury and boron. The other resins present may be natural (or esters thereof), coumarone, indene, cellulose ether, polyvinyl chloride, acetate, alcohol, ethers or acetals, polyacrylic or polymethacrylic esters, polystyrene, polyisobutylene, polyesters, alkyds, maleic acid, phenol-formaldehyde (especially colophony-modified), urea-formaldehyde, melamine-formaldehyde, aldehyde, ketone, polyamides or polyurethanes. The poly-N-vinylcarbazole is dissolved or dispersed in a liquid such as water, benzene, methylene chloride, dioxan, chloroform, trichloroethylene, methoxyethanol, butanol, tetrahydrofuran, methanol, ether or toluene, with or without one of the above additives, and coated on the support or cast as a foil. Examples are given showing as specific additives Rhodamine B, Rose Bengal, Ethyl Violet, Acid Violet, Victoria Blue, a ketone resin, a urea-foramldehyde resin, a polyindene resin, ammonium thiocyanate, mono- and dichloroacetic acids, zinc chloride, toluene-p-sulphonic acid, sulphuric acid, ferric chloride, boron trifluoride, anthraquinone, 2-methyl-anthraquinone, pyrene-3-aldehyde, benzil, indane-1 : 3-dione, acenaphthenequinone dichloride, phthalic anhydride and 1-chloro-anthraquinone. A developer for the electrostatic image is described, consisting of small glass balls with a minor amount of a "toner" made of a polystyrene resin, a modified maleic resin and carbon black. The glass balls can be replaced by methyl cellulose.
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