JPH06118694A - Color toner for flash fixing and method of manufacturing the same - Google Patents

Abstract

PURPOSE:To inexpensively obtain sufficient fixing strength without clouding the colors of color toners by fixing an IR absorbent to the surfaces of toner particles prepd. by dispersing coloring agents into a resin. CONSTITUTION:The IR absorbent absorbs the light energy of flash light and dissolves the binder resin from the surface when the flash light is cast to the toner fixing the IR absorbent on the surfaces of the toner particles. The sufficient fixing strength is thereby obtd. Since the IR absorbent is fixed to the surfaces, the IR absorbent does not peel from the toner even if the toner is used as a developer. There is thus no need for special consideration in ordinary use. The resulted color images do not cloud the colors. The binder resin is exemplified by resins, such as polystyrene and styrene and acrylate and is more preferably exemplified by epoxy resins, such as polyester resin and bisphenol A/epichlorhydrin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner for flash fixing in an electrophotographic system, more specifically,
The present invention relates to a color toner for an electrophotographic developer for flash fixing of an electrophotographic printer having a fixing system using flash light.

[0002]

2. Description of the Related Art Conventionally, as an image fixing method for an object to be printed in an electrophotographic printer, a heat roll method in which toner is pressure-bonded to paper through heat rolls, or by passing through a heating oven, infrared rays fix the toner. The oven method is used. However, these fixing methods have problems such as (1) when the paper is jammed in the fixing unit, the paper remains under pressure, and (2) there is a risk of fire. Therefore, in recent years, development of a fixing method using a flash fixing method has been advanced.

In the flash fixing method, the colorant particles, which are a component of the toner, absorb the strong light of flash light to instantaneously raise the temperature, the binder resin itself is melted, and then it is solidified again for fixing. Is the way.

As a toner for electrophotography used in the flash fixing method, Japanese Patent Application Laid-Open No. 56-30139 discloses a technique using an epoxy resin as a binder resin and carbon and a dye as a colorant. No. 71276 discloses an epoxy or polyester resin as a binder resin,
Each technology using carbon as a colorant is disclosed.

[0005]

These flash-fixing electrophotographic toners rely on colorant particles for light absorption, and have a low light absorptivity when attempting flash fixing with color toners other than black. In addition, fixing failure occurs, and the power of flash fixing must be doubled or more, or other heat fixing means must be used together, which leads to increase in size of the apparatus and increase in power consumption. As a method for solving such a problem, JP-A-63-161460 proposes to add an infrared absorbing agent to the toner.

However, JP-A-63-161460
The color toner for flash fixing proposed in the above publication is manufactured by simply melt-kneading a binder resin, a colorant and an infrared absorber. According to this manufacturing method,
Since the infrared absorber is also kneaded inside the toner particles,
In order for the color toner to obtain sufficient fixing strength, it is necessary to add a large amount of the infrared absorbing agent, but if the infrared absorbing agent is added in a large amount, the infrared absorbing agent itself has coloring properties, so that the color of the color toner is There is a problem that the toner price becomes high because of the drawback of becoming turbid and the infrared absorbing agent being very expensive.

The problem to be solved by the present invention is to reduce the amount of the infrared absorbing agent added to the color toner, thereby making it possible to obtain a sufficient fixing strength at low cost without clouding the color of the color toner. To provide a color toner for use.

[0008]

As a result of intensive studies for solving the above-mentioned problems, the inventors of the present invention have found that when infrared light absorbent is fixed on the surface of toner particles, the toner absorbs infrared light. The agent absorbs the light energy of the flash light, dissolves the binder resin from the surface, and sufficient fixing strength is obtained, and the infrared absorber is fixed on the surface, so even if it is used as a developer, the infrared absorber from the toner The present invention has been completed by finding out that no special consideration is required for normal use because it does not separate and that the color of the obtained color image does not become turbid.

That is, in order to solve the above-mentioned problems, the present invention is characterized in that (1) an infrared absorber is adhered to the surface of toner particles formed by dispersing at least a colorant in a resin. Flash fixing toner for toner and (2) first step of kneading at least colorant and resin and then crushing, and second step of adding infrared absorber to the crushed product obtained in the first step and crushing A method for producing a flash fixing toner for electrophotography according to (1) above is provided.

Examples of the binder resin used in the present invention include polystyrene type, styrene-acrylic acid ester or methacrylic acid ester copolymer, acrylonitrile or maleic acid ester-containing styrene copolymer system, polyacrylic acid ester type, polymethacrylic acid type. Examples thereof include acid ester-based, polyester-based, polyamide-based, epoxy-based, phenol-based, hydrocarbon-based, petroleum-based resins, and the like, with preference given to polyester resins and epoxy resins such as bisphenol A / epichlorohydrin. These resins may be used alone or in combination, but other resins and additives may be used in combination.

As the colorant for the color toner used in the present invention, typical pigments such as magenta, cyan and yellow can be used. The proportion of the colorant used is preferably in the range of 2 to 15 parts by weight with respect to 100 parts by weight of the binder.

Table 1 shows examples of magenta pigments that can be preferably used in the present invention. These pigments can be used alone or in a mixture of two or more.

[0013]

[Table 1]

Table 2 shows examples of yellow color pigments that can be preferably used in the present invention. These pigments can be used alone or in a mixture of two or more.

[0015]

[Table 2]

Table 3 shows examples of cyan pigments that can be preferably used in the present invention. These pigments can be used alone or in a mixture of two or more.

[0017]

[Table 3]

As the infrared absorber used in the present invention,
For example, “IRG-002” and “IGR” manufactured by Nippon Kayaku Co., Ltd.
-003 "and the like.

A dye or a charge control agent may be used as a colorant in the toner of the present invention.

Examples of dyes include C.I. I. Solvent Red 24, C.I. I. Solvent Violet 13, C.I. I. Solvent Blue 7, C.I. I. Solvent Blue 35, C.I. I. Solvent Green 35, C.I. I. Solvent Brown 5, C.I.
I. Solvent Yellow 2, C.I. I. Solvent
Yellow 14, C.I. I. Solvent orange
7, C.I. I. Solvent C.I. I. Solvent Red 3 and the like can be mentioned.

The charge control agents are classified into positive charge control agents and negative charge control agents, and these charge control agents are preferably colorless or light colored. Examples of the positive charge control agent include "Bontron P-51" manufactured by Orient Chemical Co., Ltd., and the like. Examples of the negative charge control agent include salicylic acid or metal complex compounds of esters of salicylic acid and alkyl alcohol, and examples of commercially available products thereof include “Bontron E-84” manufactured by Orient Chemical Co., and the like.

Further, in order to prevent the occurrence of a "void" of a fixed image, that is, a phenomenon in which a missing portion such as a sponge hole occurs when the toner layer transferred to the paper is fixed on the toner of the present invention, A natural wax and a polyolefin wax can also be used in combination.

Examples of natural waxes include carnauba wax.

Examples of polyolefin waxes include "Viscole 660P" and "Viscole 550P" (polypropylene wax) manufactured by Sanyo Chemical Industries.

[0025]

EXAMPLES Hereinafter, magenta electrophotographic flash fixing toners will be described by way of examples, but the present invention is not limited thereto. In the following examples, "part" means "part by weight".

(Example 1) "Polycizer R32" (polyester resin manufactured by Dainippon Ink and Chemicals, Inc.) 91 parts "Fastgen Super Magenta R" (magenta color pigment manufactured by Dainippon Ink and Chemicals, Inc.) 5 parts "Bontron P-51" (positive charge control agent manufactured by Orient Chemical Co., Ltd.) 2 parts "Viscor 660P" (polypropylene wax manufactured by Sanyo Kasei Co., Ltd.) 2 parts were heated and kneaded, and then coarsely crushed , A crude product (SM-1) was obtained.

Next, 98 parts of the coarsely crushed product "SM-1" was added with "I".
RG-003 "2 parts (Infrared absorber manufactured by Nippon Kayaku Co., Ltd.)
After mixing and mixing, the mixture was further pulverized and classified to have an average particle size of 11.
1 μm magenta toner (M-1) was obtained.

(Example 2) "Epiclone 4050" (epoxy resin manufactured by Dainippon Ink and Chemicals, Inc.) 46 parts "Epiclone 7050" (epoxy resin manufactured by Dainippon Ink and Chemicals, Inc.) 45 parts "First Gen Super Magenta R ”5 parts“ Bontron P-51 ”2 parts“ Viscole 660P ”2 parts were heated and kneaded, and then coarsely pulverized to obtain a coarsely pulverized product (SM-2).

Next, 98 parts of the coarsely crushed product "SM-2" was added with "I".
2 parts of RG-003 ”was added and mixed, and then further pulverized and classified to obtain a magenta toner (M-2) having an average particle diameter of 10.8 μm.
Got

(Comparative Example 1) "Polycizer R32" 89 parts "Fastgen Super Magenta R" 5 parts "Bontron P-51" 2 parts "Viscor 660P" 2 parts "IRG-003" 2 parts after heating and kneading, Coarse pulverization and further pulverization classification were performed to obtain magenta toner (M-3) having an average particle diameter of 11.4 μm.

Comparative Example 2 "Epiclone 4050" 45 parts "Epiclone 7050" 44 parts "Fastgen Super Magenta R" 5 parts "Bontron P-51" 2 parts "Viscor 660P" 2 parts "IRG-003" 2 parts Was kneaded by heating, coarsely pulverized, and further pulverized and classified to obtain a magenta toner (M-4) having an average particle diameter of 11.0 μm.

(Comparative Example 3) 87 parts of "Polysizer R32""Fastgen Super Magenta R" 5 parts "Bontron P-51" 2 parts "Viscole 660P" 2 parts "IRG-003" 4 parts were heated and kneaded. Coarse pulverization and further pulverization and classification gave magenta toner (M-5) having an average particle size of 10.9 μm.

(Evaluation) 3 parts of various toners and an average particle size of 60-
An unfixed image is created by developing with a commercial copying machine remodeling machine using a developer mixed with 100 parts of iron oxide powder carrier of 80 μm. Using an external fixing tester equipped with a xenon flash lamp manufactured by Ushio Electric Co., Ltd., the unfixed image was flash-fixed at 1 joule / cm ² pulse, and the results of toner fixability, voids and color tone were evaluated. The results are shown in Table 4.

The fixing property evaluation method was carried out by a tape peeling method, and the image density remaining rate of 85% or more was evaluated as ◯, and 75 to
85% was Δ, and 75% or less was X.

Remaining rate (%) = (image density after tape peeling / initial image density) × 100

In the color tone evaluation method, the standard color tone was visually evaluated for dullness.

[0037]

[Table 4]

As is clear from Table 4, the toners M-1 and M-2 of the examples of the present invention have good fixability and color tone, while the toners M-3 and M-4 of the comparative examples have good fixability and color tone. , The color tone was good, but the fixability was poor.

Further, the toner M-5 of the comparative example has a good fixability, but has a dull color tone, resulting in poor toner characteristics.

[0040]

EFFECTS OF THE INVENTION The color toner for flash fixing of the present invention requires a small amount of the infrared absorbent, and since the infrared absorbent covers the toner surface, it efficiently absorbs the light of the flash lamp and is excellent. It is possible to realize excellent fixing property.

Claims (2)

[Claims] 1. A flash fixing toner for electrophotography, characterized in that an infrared absorbing agent is fixed to the surface of toner particles formed by dispersing at least a colorant in a resin. 2. A first step of at least crushing a colorant and a resin and then crushing the mixture, and a second step of crushing the infrared-absorbing agent to the crushed product obtained in the first step. The method for producing a flash fixing toner for electrophotography according to claim 1.