JPS6271966A - Negatively chargeable red toner - Google Patents

Abstract

PURPOSE:To obtain a high quality red image by combinedly using specified two kinds of red pigments. CONSTITUTION:This negatively chargeable red toner contains a 2:1 type metallic compex salt red pigment obtd. by metallizing a monoazo dye represented by formula I, concretely by formula I-(1) and two or more kinds of red monoazo pigments selected from a group of pigments represented by formula II. The triboelectric chargeability and color tone are improved by combinedly using those pigments. The preferred total amount of the pigments used is 2-25pts.wt. per 100pts.wt. binding resin. In case of 5-15pts.wt., an especially fine color tone is obtd.

Description

[Detailed description of the invention] Technical field.

The present invention relates to negatively charged toners for developing electrostatic latent images.

Prior Art Conventionally, toners for developing electrostatic latent images have been prepared using polystyrene resin, styrene-acrylic monomer copolymer resin, styrene-methacrylic monomer copolymer resin, saturated or unsaturated polyester resin, etc. as a binder, and a colorant. Particles obtained by melt-kneading carbon black, dyes, organic pigments, inorganic pigments, etc. using two rolls and pulverizing the resulting particles to a size of about 1 to 30 microns have been used. Such toners are typically 50 to io
It is mixed with a carrier r1 (chitria) such as iron powder, glass beads, and ferrite having a particle size of approximately ooμ, and is used for developing electrostatic latent images.

In order for the toner and carrier to be used to develop the electrostatic latent image, a certain amount of frictional electrification must occur inside the copying machine, and toner with a stable amount of charge must be supplied to the electrostatic latent image. . For this purpose, the binder resin or dye in the toner,
It is necessary to select the pigment to have the desired triboelectric charging properties or to mix a charge control agent into the toner.

In the case of color toner, a desired pigment is generally dispersed in a binder and the toner is prepared in the same manner as above.
The pigment is the function of the color, but it imparts triboelectricity to the toner, which has the disadvantage of not achieving the desired chargeability.

For example, monoazo dyes (e.g., JP-A-56-140357
No.) had good color tone, but poor triboelectric charging properties.

In addition, metal-containing monoazo pigments (e.g., Japanese Patent Publication No. 43-1795
No. 5) has good triboelectrification and properties, but the color tone is dark and does not give a clear red color.

Purpose The purpose of the present invention is to produce a henna which is triboelectrically charged and has a clear red color tone.

Structure The present invention contains a 2:1 type metal salt red pigment obtained by metallizing a monoazo dye represented by the following general formula (I) and a red pigment with 2FF or more selected from the liver of structural formula (II). This is a negatively charged red toner characterized by:

General formula (I)
H2, SO3Na 1 Iha hydrogen, X3 is -NO2 Aiha hydrogen, X4 is NO2, 5o3Na or hydrogen,
x5 is water Fil group) Specific examples of compounds include the following. Of course, it is not limited to these.

I CH.

The combination of the pigment represented by the structural formula (I[) and the red monoazo pigment represented by the group represented by the structural formula (I) improves triboelectric charging properties and color tone.

The binder resin used in the present invention includes polystyrene, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and styrene-methacrylic acid copolymer, which have been conventionally used in toners.
Styrenic resins such as acrylic ester copolymers, styrene-methacrylic ester copolymers, styrene-butadiene copolymers, saturated polyester resins, unsaturated polyester resins, epoxy resins, phenolic resins, maleic resins, coumaron resins, Examples include chlorinated paraffins, xylene resins, vinyl chloride copolymers, and mixtures of these resins.

In addition to these, it is also possible to add various auxiliary agents such as plasticizers and resistance adjusters for the purpose of adjusting the thermal properties, electrical properties, and physical properties of the toner.

The ratio of the binder resin to the above-mentioned pigment is preferably 2 to 25 parts by weight of Pigment 1+Ir to 100 parts by weight of the binder resin, and a particularly preferable color tone is obtained at 5 to 15 parts by weight.

The mixing ratio of the rough pigment and the pigment (1) is preferably 1 to 9.5 parts by weight to 05 to 9 parts by weight of IO.

The more Face II there is, the more stable the charge on the toner becomes, but the tone deteriorates, and the more there is Pigment II, the more the tone changes, but the charge becomes more unstable.

Further, in the present invention, if the desired chargeability cannot be obtained with the above pigment alone, any other charge control agent may be added.

Further, the toner of the present invention is mixed with a carrier and used for developing a positive latent image, but carriers for the toner of the present invention include iron powder, nickel powder, glass beads, ferrite powder, and other powders such as these. Styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, acrylic ester polymer, methacrylic ester polymer, silicone resin, polyamide resin, ionomer resin, polyphenylene, sulfide resin, etc. or mixtures. A surface coated with is used.

Next, the present invention will be explained with reference to Examples.

Example 1 Styrene-n-butyl allerylate copolymer (manufactured by Sanyo Kasei, SBM-73) 100 parts pigment (■ Diba Geigy, Orazole Red 28L) Triple part pigment (■ Manufactured by Dezumi Shiki) , Bigmen 1-Red 4BS) 7 or more layers are melt-kneaded with hot rolls, cooled, coarsely crushed using a hammer mill, and then finely pulverized using an air jet type pulverizer. The milled fine powder is classified and 3 to 25 microns are selected and used as toner.

This toner has a carrier (ferrite powder of 50 to 150μ coated with silicone resin).
1 part of 100fi was mixed and used as a developer.

Using this developer, a dry type concave paper duplex Tf machine (manufactured by Ricoh,
When development was carried out using 1-40 (30), a red image with no fog was obtained. The amount of charge on the toner is −
It was 13.4 μC/(]. No deterioration in copy quality was observed even after 20,000 copies were made continuously.

Example 2 A developer of the present invention was prepared in the same manner as in Example 1, except that the pigment (1) was replaced with [Fuji Fast Red 5R #7807 (+Kikufuji Color Co., Ltd.)].

When this developer was used in a dry plain paper copying machine (FT-4060 manufactured by Ricoh Co., Ltd.), a fog-free red image was produced. The charge m of the toner was -17.9 μC/Q. No deterioration in copy quality was observed even after continuous copying of 20,000 copies.

Example 3 Pigment ■ of Example 1 was mixed with [Fuji First Red 7R# 3300 ([(3)
A developer of the present invention was prepared in the same manner except that the developer (manufactured by Fuji Shiroki Co., Ltd.) was replaced. Dry plain paper copying 1 using this developer
When step (9) was carried out using FT-4060 manufactured by Ricoh Co., Ltd., a red image without fogging was obtained. The charge of the toner was -10.9 μC/g.

No deterioration in copy quality was observed even after continuous copying of 15,000 sheets.

Effects By using two specific red pigments in combination, the present invention exhibits strong negative chargeability with respect to carriers, has no deterioration in copy quality during continuous copying due to repeated use, and has high heat resistance. , a toner with excellent weather resistance and stable charging against changes in wet marks can be obtained. Therefore, a high quality red image can be obtained.

Claims (1)

[Scope of Claims] A 2:1 type metal complex salt red pigment obtained by metallizing a monoazo dye represented by the following general formula (I) and a structural formula (
A negatively charged red toner comprising two or more red pigments selected from the group II). General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, X_1 is hydrogen, X2_ is -NO_2, S
O_2NH_2, SO_3Na, or hydrogen, X_3
is -NO_2 or hydrogen, X_4 is NO_2, SO_
3Na or hydrogen; There are ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼