JPS6215555A - Color electrophotographic toner - Google Patents

Abstract

PURPOSE:To prevent dyeing of a fixing roller made of a silicone rubber and to extend the life of the roller so as to attain durability corresponding to >=20,000 sheets of copies by using a specified rhodamine type dye. CONSTITUTION:The toner contains the rhodamine having the structure of formula 1, preferably, in an amount of 1.0-2.0wt% of the total binder, alone or in combination with other dyes or pigments not dyeing the rollers. As the dyes and pigments not dyeing the rollers, azo dyes and the like are enumerated, and as the binder to be used, unsaturated polyesters are especially effective.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a color toner used in color electrophotography, and particularly to a magenta toner suitable for a color copying machine using a silicone rubber roller heat fixing device.

[Prior Art] Coloring agents for conventional magenta toners for color electrophotography include azo lake pigments, rhodamine pigments and dyes, quinacridone pigments, and anthraquinone dyes. Among them, rhodamine dyes have good color properties (clear colors can be obtained) and high tinting power, making them ideal as magenta coloring agents.

Rhodamine B base dye having a structure as a rhodamine dye] (trade name Rhodamine Base FB, manufactured by BASF) was published in Japanese Patent Application Laid-Open No. 59-57.
It was introduced in Publication No. 256 and is widely used.

However, this dye easily permeates into the silicone rubber roller, dyes the roller surface magenta, reduces the releasability of the roller surface, and has the disadvantage that offset tends to occur early. Therefore, the rollers must be replaced within a short period of time, which increases service costs significantly.

[Problems to be Solved by the Invention] An object of the present invention is to provide a magenta toner for color electrophotography using a rhodamine dye, which solves the above-mentioned drawbacks.

That is, the present invention provides a coloring agent for magenta toner that does not impair the characteristics of rhodamine dyes, such as excellent vivid color and high degree of coloring, and does not stain a silicone rubber fixing roller.

[Means for Solving the Problems and Effects] The present invention comprises a magenta toner for color electrophotography, which is characterized by containing a rhodamine dye having the following structure.

↓ The rhodamine dye used in the present invention has the above structural formula and is C,1,Ba5ic Red 1.

The content of the rhodamine dye used in the present invention is 0.00% relative to the total binder. It is possible to range from 1 to 10.0 wt%, but preferably from 1.0 to 2.0 wt%. As a coloring agent, the rhodamine dye used in the present invention can be used alone or in combination with other dyes and pigments that do not dye the roller. Examples of dyes and pigments that do not dye the roller include azo dyes and rhodamine dyes, as well as various dye lake pigments, quinacridone pigments, anthraquinone dyes, and thioindigo pigments.

Thermoplastic resins used as binders include styrene resin, polyacrylic acid ester, polyacrylic acid, polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, polyamide, phenolic resin, unsaturated polyester, maleic resin, alkyd resin, etc. can be mentioned, but
Among them, unsaturated polyesters are particularly effective.

A general method for producing the magenta toner containing the specific rhodamine dye of the present invention is as follows.

■Distribute the resin and colorant (charge control agent in some cases) uniformly using a Henschel mixer, etc.;
Melt and knead with an extruder, roll mill, etc.; ■ Coarsely crush the kneaded material with a cutter mill, hammer mill, etc., and then finely crush it with a jet mill, etc.; ■ Classify the finely crushed material with a zigzag classifier, etc.; ■ Classify the product. Disperse silica, etc., if necessary.

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

Example 1 Styrene-butyl methacrylate copolymer (trade name Hymer SBM73, manufactured by Sanyo Kasei ■) 100 parts by weight Rhodamine dye used in the present invention (trade name Rhodamine 6GCP, Basic Red 1, manufactured by Taoka Chemical ■) 2 parts by weight Dioxazine pigment (trade name PV Fast Violet BL, manufactured by DIC)
1 part by weight rose phenylphenol resin (for polarity control) (
(trade name: PP-8ti, manufactured by Gunei Kagaku ■) 10 parts by weight The above materials were melt-kneaded in a roll mill, cooled, pulverized in a jet mill, and classified to obtain products classified into 5 to 20.

Add 0.5% hydrophobic silica (product name R-97) to this classified product.
2. Nippon Aerosil ■) was added externally to obtain a magenta toner.

This is carrier iron powder (product name: TEFV200/300,
(manufactured by Nippon Iron Powder ■) to prepare a developer.

Using this developer, a full-color copying machine (product name: Color T)
I made 20,000 copies in a row using Canon's
No image staining due to offset occurred.

When the silicone rubber fixing roller was observed, no staining with the above-mentioned rhodamine dye occurred.

Example 2 Unsaturated polyester resin (trade name Atrac 382A, manufactured by Kao Seki) Too parts by weight Specific rhodamine dye of the present invention 2 parts by weight Rhodamine Lake pigment (trade name Rhodamine B Lake, manufactured by DIC) 1 weight Part Charge control agent (chromium alkyl salicylate complex compound) 2 parts by weight Using the above materials, toner was prepared and evaluated in the same manner as in Example 1, and the quality was sufficiently satisfactory.Example 3 Styrene resin (commercial product) Picolastic D125, manufactured by Vercules) 90 parts by weight Paraphenylphenol resin 10 parts by weight Specific rhodamine dye of the present invention 2 parts by weight Anthraquinone dye (trade name Macrolex Red 5B, manufactured by Bayer) 1 part by weight of the above materials A toner was prepared and evaluated in the same manner as in Example 1. No roller staining or offset occurred.

Comparative Example Unsaturated polyester resin (trade name Atrac 382A,
(manufactured by Kao Soap ■) 90 parts by weight Rose phenylphenol resin 10 parts by weight Rhodamine dye (trade name Rhodamine Base FB, manufactured by BASF) 2 parts by weight Anthraquinone dye (trade name Macrolex Red 5B, manufactured by Bayer) 1 part by weight A toner was produced using the above materials in the same manner as in Example 1, and evaluated.

After continuous copying started, the fixing roller began to be dyed magenta from around 5,000 sheets, and hot offset occurred at 7,000 sheets.

When the fixing roller was observed, significant staining had occurred.

[Effects of the Invention] As explained above, in the present invention, by using a specific rhodamine dye, staining of the silicone rubber fixing roller is eliminated, the life of the roller is improved, and 20.
Durability of over 1,000 sheets was obtained.

Claims (1)

[Claims] (1) A magenta toner for color electrophotography, characterized by containing a rhodamine dye having the following structure. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼