Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Patent
1999-07-30
2000-08-29
Goodrow, John
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
4301066, G03G 9097
Patent
active
061106348
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention is to provide an electrophotographic toner used to develop an electrostatic latent image in the fields of electrophotography, electrostatic recording, etc., characterized by containing a combination of a compound useful as a charge control agent and various binder resins.
BACKGROUND ART
In an image-forming process by means of an electrophotographic system, an electrostatic latent image is formed on a photoconductive material made of an inorganic or organic material, and the latent image is developed by a toner, then transferred and fixed on a paper sheet or plastic film to obtain a visible image. The photoconductive material may be positively electrifiable or negatively electrifiable depending upon its construction. When a printed portion is remained as an electrostatic latent image by exposure, development is conducted by means of an oppositely electrifiable toner. On the other hand, when a printed portion is destatisized for reversal development, development is conducted by means of an equally electrifiable toner.
A toner is composed of a binder resin, a coloring agent and other additives. However, in order to impart desired tribocharge properties (such as desired charge up speed, tribocharge level and tribocharge level stability), stability with time and environmental stability, it is common to use a charge-control agent. The properties of the toner will be substantially affected by this charge-control agent. When a positively electrifiable photoconductive material is used for development by an oppositely electrifiable toner, or when a negatively electrifiable photoconductive material is used for reversal development, a negatively electrifiable toner is used. In such a case, a negatively electrifiable charge-control agent is added. Further, in a case of a color toner for which the market is expected to expand in future, it is necessary and indispensable to use a pale-colored or preferably colorless charge-control agent which does not affect the color of the toner. Such pale-colored or colorless charge-control agents may, for example, be metal complex salt compounds of salicylic acid derivatives (e.g. JP-B-55-42752, JP-A-61-69073 and JP-A-61-221756), aromatic dicarboxylic acid metal salt compounds (e.g. JP-A-57-111541), metal complex salt compounds of anthranilic acid derivatives (e.g. JP-A-62-94856) and organic boron compounds (e.g. U.S. Pat. No. 4,767,688 and JP-A-1-306861). However, these charge-control agents have various drawbacks such that some of them are chromium compounds which are feared to be detrimental to environmental safety which is expected to be viewed as increasingly important, some of them are compounds which can not be made adequately colorless or pale-colored as required for toners, some of them have inadequate electrifying effects or provide oppositely electrifiable toners, or some of them are poor in dispersibility or chemical stability as compounds themselves. Thus, none of them has fully satisfactory properties as a charge-control agent. Accordingly, it is an object of the present invention to provide an electrophotographic toner which is excellent in the tribocharge property and capable of constantly and stably presenting an image of high image quality, characterized by using a specific combination of a binder resin and a compound which is colorless or pale-colored and excellent in environmental safety and has a high stability as a compound and which is useful as a charge-control agent for the electrophotographic toner and excellent in the dispersibility in the binder resin.
DISCLOSURE OF THE INVENTION
In order to solve these problems, the present inventors have paid an attention to zirconium (Zr) being a tetravelent metal as the main metal, and have synthesized and studied various compounds of a tetravalent cation or a bivalent cation being an oxo complex with salicylic acid or a salicylic acid derivative. As this result, they have obtained a compound which is colorless or pale-colored and is able to impart a good tribocharge propert
REFERENCES:
patent: 5804350 (1998-09-01), Sekiguchi et al.
patent: 5827631 (1998-10-01), Yoshihara et al.
patent: 5919866 (1999-07-01), Rao et al.
Murakami Rie
Muraoka Taito
Saitoh Yutaka
Sawano Masataka
Yamaga Hiroyoshi
Goodrow John
Hodogaya Chemical Co. Ltd.
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