JPS59200253A - Positive electrostatic cheargeable toner for two- component developer - Google Patents

Abstract

PURPOSE:To obtain satisfactorily not only black but also-color toners which charge stably electrostatically to positive by incorporating 4-amino-2.6-bix (dimethyl amino)pyrimidine in a binder resin. CONSTITUTION:The 4-amino-2.6-bis(dimethyl amino)pyrimidine expressed by the formula is incorporated as an electrostatic charge controlling agent into a toner binder resin. Such pyrimidine compd. is white and is used at about 0.5-10pts.wt. in 100pts.wt. the binder resin. The toner incorporated therein with such pyrimidine compd. is used together with a carrier such as iron powder and is stably charged with positive charge by friction contact. Carbon powder, etc. are usable as the coloring agent in the case of a black toner and an azo dye and various other dyes are usable in the case of a color toner. A sharp color image free from photographic fogs is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION +l) Technical Field of the Invention The present invention relates to a two-component developer used in electrophotography, and particularly to a toner that is positively charged by frictional charging with a carrier.

(2) Background of the technology Two-component developers used in electrophotography are composed of glass beads or iron powder called carrier and fine resin powder called toner. In the magnetic brush development method, carrier and toner are mixed (stirred) in a developing device with a magnetic roll, and the toner is charged to a desired polarity and charge amount to develop an electrostatic latent image previously formed on a photosensitive drum. It turns out.

Toner, which is a fine resin powder, is generally prepared by adding and mixing a basic resin colorant, a charge control agent, a fluidity improver, etc., and kneading the mixture using a heated roll mill or kneader.

Thereafter, it was coarsely pulverized and finely pulverized to obtain a powder with a particle size of approximately 10 μm. Since the toner develops the electrostatic latent image on the photosensitive drum, it must have charging characteristics necessary for development.

(3) Prior Art and Problems Conventionally, resin acid-modified nigrosine dyes and polyamine resins are known as charge control agents used in positively charging toners for developers, which are components that are positively charged by frictional contact with carriers. The former is a dye with only one color, so it is almost possible to apply it to black toner.

It cannot be applied to color toners other than black.

Since the latter is a white charging agent, it can be used as a charge control agent for various color toners, but there are problems with its dispersibility in resins and its poor <411 chargeability. For these reasons, the amount of charge is stable, and 1. There is a need for a charge control agent that can also be applied to color toners.

(4) Purpose of the Invention The purpose of the present invention is to use white 4-amino-26-his(dimethylamino)pyrimidine having the chemical structural formula shown below as a toner charge control agent, thereby creating a stable positive charge through friction with the carrier. 4'rTx charged.

Moreover, it is an object of the present invention to provide a positively charged toner for a two-component developer that can be applied to black toner and toners of colors other than black.

The present invention provides (1) 4-4 having the following chemical structural formula in the toner binder resin.
Positively charged toner for two-component developer characterized by containing amino-246-his(dimethylamino)pyrimidine (2) Addition amount of 4-amino-2,6-bis(dimethylamino)pyrimidine or binder resin 0.0% per 100 parts by weight.
This is achieved by a positively charged toner for a two-component developer characterized in that the amount is 5 to 10 parts.

The present invention will be described in detail below. As the resin for the toner of the present invention, any conventionally used resin can be used, such as polystyrene-2-polyethylene and styrene-acrylic copolymer.

Examples include styrene-butadiene polymers, polyamides, epoxy resins, coumaron resins, and rosin resins. These resins can be used alone or in combination of two or more. The amount of 4-amino-2,6-bis(dimethylamino)pyrimidine used in the present invention, which is a positive charge control agent, is 0.51 parts by weight per 100 parts by weight of the resin.
It can be used in a range of 0 parts by weight. 4.Amino-2
, the amount of 6-bis(dimethylamino)pyrimidine added is 0.
If the amount is less than 5 parts by weight, the effect of 4-amino-2,6-his(dimethylamino)pyrimidine as a positive charge control agent will not be fully exhibited, and if it is added more than 10 parts by weight, it will be difficult to mix uniformly with the resin. As a result, the charging properties of the final product, the toner, become inconsistent.

In addition to the above-mentioned resin and charge control agent, various conventionally known colorants can be used in the toner of the present invention. In other words, in the case of black toner, nigrosine dye or carphone powder, and in the case of color toners other than black, 2
Azo dyes such as monoazo dyes and disazo dyes, locumin dyes, quinacridone dyes, hensicine yellow, copper phthalocyanine dyes, and the like can be used. Furthermore, the present invention will not be hindered in any way by appropriately using flow modifiers such as silica powder, alumina powder, and polyfluorinated powder.

The toner of the present invention can also be manufactured by conventional techniques. That is, 4-amino-2,6-his(dimethylamino)pyrimidine, which is a positive charge control agent of the present invention, is added and mixed to the basic resin, and a coloring agent and a property modifier are added and kneaded in a kneader or hot roll mill. . Thereafter, the powder is coarsely ground using a hammer mill or a rotoplex, and then finely ground using a rotary mill. After that, a powder of about 5 to 20 μIn is classified and collected using an air classifier and used as a toner.

(6) Examples of the invention [Example 1] Resin 2 charge control agent with the following composition and pigment have an average particle size of lO
A positively charged red toner of μm was prepared by the conventional manufacturing method described above.

Polystyrene resin 100 parts by weight (Picolastic D125 manufactured by Enoso) 4-amino-2,6-his(dimethylamino)pyrimidine 3 parts by weight Quinacridone pigment (Shinkasha RT~759D manufactured by DuPont) 3 parts by weight (3 parts by weight of η-treated toner) Spherical iron powder (S
T-2 (10 Kanto Denka) and 97 parts by weight were mixed to prepare a developer. We mounted this on a F6715D laser printer manufactured by Fujitsu (Tenba) and conducted a printing experiment.As a result, we were able to obtain a good red image with no fogging in the background, and even after printing 100,000 sheets, the print quality was no different than the initial print quality. No comparison was found.

Also, the amount of charge of this developer is determined by the powder charging charge/! +18°3μ when measured using a meter (Toshiba Chemical Co., Ltd.)
C/g (2.7%).

[Example 2] A blue toner was prepared with the following composition.

Epoxy resin 100 parts by weight (Shell Chemical Epicoat #1007) 4ami2-2,6-bis (
Dimethyl) pyrimidine 3 parts by weight Copper phthalocyanine pigment 3 parts by weight (Sumitomo Chemical Liono Blue ES) Using this toner, the same experiment as in Example 5 was conducted. The initial printing performance was good, and even after printing 100,000 sheets, the same printing quality as the initial printing quality could be obtained. The charge amount of this toner is +17.5μC/g (toner concentration 3.0%)
Met.

(7) Effects of the Invention The present invention uses 4-amino-2,6-his(dimethylamino)pyrimidine as one of the toner components to produce a toner that is charged to a good positive polarity by contact with the carrier. It is possible to obtain a toner that can perform clear printing. Furthermore, since the above substance is white, it can be applied not only to black toner but also toner of colors other than black.

Claims (1)

[Claims] (1) 4- having the following chemical structural formula in the toner binder resin
Positively charged toner for two-form developer characterized by containing amino-2,6-bis(dimethylamino)pyrimidine (1) The amount of 4-amino-2,6-bis(dimethylamino)pyrimidine added 0.5 per 100 parts by weight of resin
The positively charged toner for a two-component developer according to claim 1, characterized in that the amount is 10 parts by weight.