JPS61292159A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a fine image by adding a specified benzothiazole deriv. to a toner. CONSTITUTION:A toner is mixed with a benzothiazole compound represented by formula so that the toner is negatively charged. Thus, a toner having satisfactory developing characteristics and a long life is obtd. In the formula, each of R1 and R2 is H, alkyl, aryl, aralkyl, alkoxy, halogen, nitro, alkylsulfonyl or arylsulfonyl.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner used when developing electrostatic latent images such as electrophotography or electrostatic recording.

Methods for developing electrostatic latent images using toner include the magnetic brush method, which uses developer powder containing carrier particles, mainly iron powder, and the cascade method, which uses developer powder containing glass particles as carrier particles. It has been known.

The developing powders used in these development methods include fine powders in which dyes or pigments are dispersed in thermoplastic resins, and developing powders to which a third substance is added as described in Japanese Patent Publication No. 44-6398. is also known. However, since the above developer powder alone does not have desirable charging properties, dyes or pigments that impart charging properties are added, and currently in practical use, when imparting a negative charge to toner, When a metal-containing dye imparts a positive charge, there is a nigrosine dye. These dyes are charge control agents with excellent properties, but because they are colored substances, they cannot be used in color electrophotography, which has been particularly in demand in recent years. Therefore, there is a great demand for a colorless or light-colored charge control agent for negative toner, which is currently mainly used.

Therefore, the present inventor conducted extensive research on minus toner for color electrophotography that is colorless or light-colored and has good development characteristics, and as a result, arrived at the present invention.

That is, the present invention provides a toner for use in developing an electrostatic image, which has the following general formula (I) (wherein R+ and Rz are a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an alkoxy group, a halogen atom, This is a toner for developing electrostatic images characterized by containing a benzothiazole derivative represented by the following (representing a nitro group, an alkylsulfonyl group, or an arylsulfonyl group).

In the substituents R,,R2 of general formula (I), a hydrogen atom,
Alkyl groups include methyl group, ethyl group, propyl group,
Butyl group, amyl group, hexyl group, trifluoromethyl group, aryl group as phenyl group, tolyl group, ethylphenyl group, butylphenyl group, aralkyl group as benzyl group, methylbenzyl group, chlorobenzyl group, alkoxy group is a methoxy group, an ethoxy group, a butoxy group, an ethoxyethoxy group, a halogen atom is a chloro atom, a bromine atom, an iodine atom, a fluorine atom, a nitro group, an alkylsulfonyl group is a methylsulfonyl group,
Typical substituents of the ethylsulfonyl group, butylsulfonyl group, and arylsulfonyl group include phenylsulfonyl group, tolylsulfonyl group, chlorophenylsulfonyl group, and methoxyphenylsulfonyl group.

In the present invention, the toner contains a thermoplastic resin, a coloring substance, and the like in addition to the charge control agent described above.

Examples of thermoplastic resins include monopolymers or copolymers such as styrene, p-chlorostyrene, and vinyltoluene, styrene-propylene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate, ethyl, and butyl acrylate. or octyl copolymer, styrene-methyl methacrylate, ethyl or butyl copolymer, styrene-acrylonitrile copolymer, styrene-isobutylene copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinyl acetate, polyethylene , polypropylene, epoxy resin, polyester, etc. alone or in combination.

Examples of colorants include dyes that do not have water-soluble groups such as sulfone groups, such as azo dyes, anthraquinone dyes, nitro dyes, and quinophthalone dyes, and pigments such as quinacridone and phthalocyanine.

The amount of the compound represented by general formula (I) mixed in the toner is usually 10% by weight or less, preferably 0.5 to 10% by weight.
It is 5% by weight.

The toner of the present invention is mixed with a carrier to form a developer and is used after being negatively charged. As the carrier at this time, for example, iron powder, glass beads, or those whose surfaces have been treated with a resin are used.

The benzothiazole compound represented by the general formula (I) of the present invention is white to pale yellow in color, and by mixing it with the toner, the toner is negatively charged and a long-life toner with good development characteristics is produced. can be manufactured.

The present invention will be explained in detail below with reference to Examples.

In the text, parts represent parts by weight.

Example 1 100 parts of styrene-butyl acrylate copolymer, 3 parts of copper phthalocyanine and the following benzothiazole derivative (I
) was uniformly premixed in a ball mill for 20 hours, then thoroughly kneaded in a heated roll mill, and finely pulverized to 1 to 40 μm to obtain a powder toner. 5 parts of the obtained toner and 9 parts of iron powder
A developer was prepared by mixing 5 parts of the developer, and copies were made using a dry type electronic copying machine. As a result, good images were obtained and the lifespan was also good.

Example 2 In Example 1, styrene-butadiene copolymer, epoxy resin, polyester resin, styrene oligomer or styrene-octyl acrylate copolymer was used instead of styrene-butyl acrylate copolymer, and the others were A powdered toner was obtained in the same manner as in Example 1, and a developer was prepared using the powder toner for copying. As a result, good images were obtained in each case.

Example 3 Benzothiazole derivative (I) used in Example 1
A powder toner was obtained in the same manner as in Example 1, except that compounds of the following structural formulas (2) to (I2) were used instead of . As a result, good images were obtained in each case.

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Claims (1)

[Scope of Claims] A toner for developing an electrostatic image, which is characterized by containing a benzothiazole derivative represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1 and R_2 are hydrogen atoms, alkyl groups, aryl groups, aralkyl groups, alkoxy groups, halogen atoms,
Represents a nitro group, an alkylsulfonyl group or an arylsulfonyl group. )