Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Patent
1990-08-21
1994-01-11
McCamish, Marion E.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
430109, 430138, 430546, 430631, 42840224, 42721336, G03G 900
Patent
active
052780171
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to (i) electric charge controlling resin for adjusting the electrostatic chargeability of toner used for developing an electrostatic latent image, (ii) toner made with the resin and (iii) a method of producing the toner.
BACKGROUND OF THE INVENTION
In the field of electrophotographic copying or electrostatic printing, it is a common practice to use, for developing an electrostatic latent image, toner in the form of colored resin particles containing coloring agents and electric charge controlling agents dispersed in a resin medium.
Generally, the toner is composed of resin particles containing coloring agents, electric charge controlling agents and the like as mixed and dispersed in binding resin. To provide the toner with desired color and electrostatic chargeability, it is a common practice to suitably change the types and blending amounts of the binding resin, coloring agents, electric charge controlling agents and the like to be used.
As a toner manufacturing method, there is generally adopted a so-called pulverization method by which a resin medium and coloring agents are molten and kneaded to prepare toner in the form of particles having a predetermined range of particle size. However, the toner thus produced by the pulverization method contains particles having irregular shapes and presents a poor fluidity. Further, the individual irregular particles of the toner are electrically, charged in considerably different manners, causing the distribution of electrostatic charge to become broad. Further, the pulverization method requires facilities of great size, resulting in increased production cost.
It is also proposed to manufacture toner by a suspension polymerization method. According to this method, a polymeric composition in the form of a mixture of an initiator of polymerization with toner characteristic imparting agents such as polymeric monomers, coloring agents, electric charge controlling agents and the like, is suspended, under stirring at a high speed, in an aqueous solution containing a dispersion stabilizer. Then, this mixture is polymerized to directly produce toner. This toner manufacturing method using suspension polymerization may directly produce toner in the form of particles of which sizes are in a practical range, at the resin polymerization step. This results in decrease in production cost. Further, this method presents the advantage that the resultant toner is excellent in fluidity and stability of electrostatic charge.
Such a toner manufacturing method using pulverization or suspension polymerization uses an electric charge controlling agent for adjusting the characteristics of toner electrostatic charge. As the electric charge controlling agent, a variety of dyes are generally used. Since the electric charge controlling agent controls the developing properties of the toner, it is important to properly select the electric charge controlling agent.
More specifically, the demands for an image forming apparatus are recently versatile according to applications and are extended to a variety of performances such as smaller-size, lower-energy, higher-speed, multi-colors, maintenance-free and the like. Accordingly, to accomodate to the developing system or inside environmental conditions of the apparatus, the toner is required to have different characteristics according to the apparatus types and colors used. Therefore, a great number of types of toner are apt to be produced in a small amount. It is therefore required to manufacture, with good reproducibility, toners of which characteristics are subtly different. In view of the foregoing, the selection of the electric charge controlling agent is important.
However, the dyes are hardly compatible with resin and a polymeric monomer. Accordingly, a great amount of dyes should be added to obtain a sufficient electrostatic charge. Further, since the dyes are present in the form of particles in resin and a polymeric monomer, the electrostatic chargeability of the resultant toner consider
REFERENCES:
patent: 4610945 (1986-09-01), Matsuoka et al.
patent: 4883735 (1989-11-01), Watanabe et al.
McCamish Marion E.
Mita Industrial Co. Ltd.
Rosasco S.
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