Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Patent
1990-04-03
1991-10-29
Goodrow, John
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
430115, G03G 908
Patent
active
050615890
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention concerns a toner. More specifically, it relates to a toner for developing electrostatic latent images for electrophotography, electrostatic recording, etc.
2. Background Art
A process for forming an image of electrostatic recording, electrophotography, etc. by utilizing static electricity comprises a step of forming a photoconductive latent image by an optical signal on photosensitive material obtained by coating photoconductive material such as selenium, cadmium sulfide or amorphous silicon on a substrate made of aluminum, paper, etc., and a step of electrically charging colored fine particles of 5-50 .mu.m referred to as a toner frictionally by means carrier (iron powder, ferrite powder, etc.) in two component development or directly in mono component development and then acting them on a photoconductive latent image thereby developing the same.
It is necessary that the toner is applied with electric charge corresponding to the polarity of a photoconductive latent image formed on the photosensitive material, that is, either positive or negative charge.
Generally, fine colored particles referred to as a toner comprises a binder resin and a coloring agent as the essential ingredient and, optionally, a magnetic powder, etc. As a method of applying electric charge to a toner, it is possible to utilize charging property of a binder resin itself without using a charge control agent, but stability to aging and moisture resistance is usually poor and no satisfactory image quality can be obtained by this method. Accordingly, a charge control agent is usually added with an aim of retaining and controlling charges of a toner. The properties required as the quality of a toner includes excellent charging property, flowing property and fixing property, and they are greatly influenced by the charge control agent used for a toner.
As the charge control agent added to a toner, there have been known, (1) colored negative charge control agents such as 2:1 metal complex salt dye (Japanese Patent Publications No. 45-26478 and No. 41-201531) and phthalocyanine pigment (Japanese Patent Application Laid Open (KOKAI) No. 52-45931), and colorless negative charge control agents as described in Japanese Patent Publication No. 59-7384 or Japanese Patent Application Laid Open No. 61-3149, (2) positive charge control agents such as nigrosine dyes, various kinds of quaternary ammonium salts (Journal of Electrostatic Society, 1980, Vol.4, No. 3, P-114). However, a toner containing these charge control agents can not satisfy the property required for the quality of the toner such as charging property and stability to aging. For instance, a toner containing 2:1 metal complex salt dye known as a negative charge control agent has a certain level of charging amount but involves a drawback that the dispersibility of the 2:1 metal complex salt dye to a binder resin is generally poor. Therefore, it does not distribute uniformly in binder resin, and the distribution for the charging amount of the resultant toner remarkably lacks in the sharpness. The resultant image obtained by using such a toner has low gradation and poor image forming performance. In addition, since the 2:1 metal complex salt dye has a hue near black color, it has a drawback that it can be used only for a toner of a restricted hue based on black color. As a nearly colorless negative charge control agent, there can be mentioned a metal complex of an aromatic dicarboxylic acid (Japanese Patent Publication No. 59-7384), but this has a drawback that it can not be completely colorless and dispersibility is not satisfactory. Further, as a colorless negative charge control agent, there has been known a compound proposed by Japanese Patent Application Laid Open (KOKAI) No. 61-3149, but the compound, having a low melting point, involves a drawback that the heat stability upon toner production is poor and production of stable toner is difficult. Accordingly, it has been demanded for the development of a toner in which the charge cont
REFERENCES:
patent: 4737432 (1988-04-01), Tanaka et al.
patent: 4886725 (1989-12-01), Tanaka et al.
Shindoh Seijin
Torigoe Michiko
Goodrow John
Nippon Kayaku Kabushiki Kaisha
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