Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Electrophoretic imaging – process – composition – or product
Patent
1983-02-22
1984-07-31
Welsh, John D.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Electrophoretic imaging, process, composition, or product
430 77, G03G 13048
Patent
active
044630760
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the use of certain electrically photosensitive merocyanine-cyanine-merocyanine (MCM) colorants in photoelectrophoretic (PEP) imaging processes, and to electrically photosensitive materials containing such colorants.
In the past, there has been extensive description in the patent and other technical literature of PEP imaging processes. Descriptions of PEP imaging processes are contained in U.S. Pat. Nos. 2,758,939 by Sugarman issued Aug. 14, 1956; 2,940,847, 3,100,426, 3,140,175 and 3,143,508, all by Kaprelian; 3,384,564, 3,384,488 and 3,615,558, all by Tulagin et al; 3,384,566 by Clark; 3,383,993 by Yen; and 3,976,485 by Groner.
In PEP imaging processes, an imaging layer comprising an electrically photosensitive material is placed between two electrodes, subjected to the influence of an electric field and exposed to an image pattern of electromagnetic radiation to which the electrically photosensitive material is sensitive. This causes electrically photosensitive components in the material to migrate imagewise in the layer to form a record of the imaging electromagnetic radiation.
Regardless of the particular PEP imaging process employed, an essential component of any such process is the electrically photosensitive material. Such materials are composed of an electrically insulating carrier containing electrically photosensitive particles which serve as the migrating components in a PEP imaging process. The particles, in turn, comprise pigments or dyes (herein referred to as colorants) which themselves are electrically photosensitive, or form electrically photosensitive colored particles in association with other photoactive materials.
Certain PEP applications require the use of a colorant which is neutral in hue. Such a neutral colorant must exhibit several properties to give optimum results. In particular, it must exhibit significant absorption across the entire visible region of the spectrum to give it a good neutral hue. It must also exhibit high electrical photosensitivity and possess good light stability.
There exists a continuing effort to find materials which possess useful levels of electrical photosensitivity and exhibit good colorant properties including neutral or near neutral coloration, as well as other desired hues.
The present invention provides electrically photosensitive materials which are useful in PEP processes. The materials comprise particles containing an electrically photosensitive merocyanine-cyanine-merocyanine (MCM) compound comprising two merocyanine moieties joined by a cyanine moiety. These compounds are colorants and contain the following structure: ##STR2## wherein: m and n, which are the same or different, are 0, 1 or 2; aryl, aralkyl, alkaryl, carbocyclic or heterocyclic group or, when taken together and p is zero, and a one- or two-carbon alkylene bridge; aryl, aralkyl, alkaryl, carbocyclic or heterocyclic group; or an alkyl group; or an alkyl group; taken together with R.sup.22 and u is 0, represent the atoms necessary to complete an alkylene or heteroalkylene bridge, represent the atoms necessary to complete an alkylene or heteroalkylene bridge, hydrogen or an alkyl group or, when individually taken together with R.sup.1 or R.sup.11, represent the atoms necessary to complete an alkylene or heteroalkylene bridge; and complete a basic heterocyclic cyanine dye nucleus; and selenium or --NR.sup.8 wherein R.sup.8 represents an alkyl, aryl, aralkyl, alkaryl, carbocyclic or heterocyclic group.
Each of the foregoing substituents on Structure I, moreover, is optionally further substituted to provide other properties as desired. For example, any alkyl or aryl group is either unsubstituted or substituted by cyano, halogen, hydroxy, sulfo, carboxy, alkoxy, or carboxyalkyl groups as desired.
The present MCM compounds can contain dissociatable counterions such as p-toluenesulfonate, chloro or iodo negatively charged counterions. Alternatively, the compounds can be zwitterionic, in which case the positively charged nitrogen is electrically balanced with a neg
REFERENCES:
patent: 4391886 (1983-07-01), Frishberg et al.
Link Steven G.
Webster Frank G.
Dahl Torger N.
Eastman Kodak Company
Welsh John D.
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