JP2002182425A - Toner for induction thermal fixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-quality stable and excellent image by restraining irregularities in an image caused by the scattering of toner under the influence of magnetic field at the time of fixing, and reducing the magnetic coupling of toner each other or the toner and a fixing means. SOLUTION: The toner for induction thermal fixing is used in an induction thermal fixing device having the fixing means including magnetic substance and includes at least soft magnetic substance and a magnetic attractive force reducing component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating fixing toner.

[0002]

2. Description of the Related Art In an electrophotographic apparatus or an electrostatic recording apparatus, a toner for visualizing an electrostatic latent image formed on an electrostatic holding member from a photosensitive member or a dielectric material is used as a medium. In the technology of fixing after transfer to
Conventionally, a heat fixing method, a pressure fixing method, a flash fixing method, an induction heating method, a combination fixing method of a flash fixing method and an induction heating method and the like are known.

In order to obtain a stable high-quality image, it is necessary to faithfully reflect the developed toner on a medium mainly composed of paper. In image formation, it is known that an image is disturbed particularly in a fixing step. On the other hand, since the fixing process consumes a large amount of energy, environmentally-friendly energy saving is desired.

Among various fixing methods, the flash method uses radiant heat of flash light of a xenon lamp, and therefore has advantages such as a short warming-up time and high safety against fire, but at the same time, it supplies a large amount of power. Therefore, there is an energy problem. Further, the flash method has a disadvantage that the image forming apparatus is enlarged.

[0005] The heat roller method has an advantage such as high safety against fire because a lamp is provided inside the roller and uses radiant heat, but has a disadvantage such as a long warm-up time.

[0006] The pressurizing method has an advantage that electric energy is not required because a high pressure is applied during fixing, but it has problems such as an increase in the size of the apparatus and a decrease in fixing characteristics.

In contrast to these methods, in the induction heating method, a coil is wound around a core, an electric current is passed through the coil, and the coil is fixed by Joule heat when a magnetic field is generated, and is used as a heat source. For this reason,
There are advantages such as a short warm-up time and high fire safety. It is also advantageous for downsizing the device.

As the toner used in the fixing method using the dielectric heating method, it has been proposed to use a non-ferrous conductive material or a magnetic powder. As a result, there is a disadvantage that toner is scattered at the time of fixing and an image is disturbed, and there is a problem that it cannot be used in the two-component developing system. Further, the toner containing only the conductive powder uses heat conduction, but does not generate Joule heat due to electromagnetic induction, and thus has a problem of deteriorating fixing characteristics.

In order to solve the above-mentioned problems, Japanese Patent Application Laid-Open No. H11-344830 proposes that a ferromagnetic material be contained in the toner. By using this toner, in addition to the heating from the induction heating means provided in the image forming apparatus, the toner itself generates Joule heat and is easily melted, so that fixing of the toner is promoted. .

However, if the toner contains a ferromagnetic material, there is a problem that offset occurs due to the magnetic coupling between the toner and the toner and the fixing means.

[0011]

Thus, according to the present invention, there is provided an induction heating fixing apparatus having a fixing means containing a magnetic material, characterized by comprising at least a soft magnetic material and a magnetic attraction reducing component. An induction heating fixing toner is provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One of the features of the present invention is to efficiently fix a toner by induction heating both a toner and a fixing means.

The fixing means in the present invention corresponds to known fixing means such as a belt and a roller. The fixing means includes a magnetic material, and as the magnetic material, for example, a simple substance of iron, cobalt, nickel, or a composite thereof, or a mixture of these simple substances with carbon, aluminum, tellurium, manganese, or the like, or Oxides and the like. Of these, a magnetic material having a residual magnetization of 100 emu / g or less is preferable. Further, a magnetic material having a holding force of 200 Oe or less is preferable.
Further, a magnetic material having all of these residual magnetization and coercive force is preferable. The components of the fixing unit other than the magnetic material are not particularly limited, and include resins such as polyester and polyimide. Further, the content of the magnetic substance in the fixing means varies depending on the magnetic quantity of the magnetic substance, but is preferably in the range of 1 to 15% by weight.

As components of the induction heating fixing device other than the fixing means, members of a known device can be used as they are. One example is shown in FIG. 1 and the fixing method will be described.
First, the toner 2 on the recording material (recording paper) 1 is transported together with the recording material 1 under a fixing belt 3 as fixing means. Next, the induction heating coil 4 also generates heat, and the toner 2 and the fixing belt 3 also generate heat. The generated heat promotes the melting of the toner, and the toner is well fixed on the recording material 1. Here, a pressure roller 5 may be provided below the induction heating coil 4 to further strengthen the fixing. In the figure, the induction heating coil 4
The lower arrow indicates the direction of magnetization, and the other arrows indicate the moving direction of each member. Here, the induction heating coil is
It may be arranged at any position of the portion where the recording paper faces the fixing belt, but is preferably arranged near the center from the viewpoint of preventing the toner from magnetically adhering to the fixing belt to cause offset. . In addition to the recording paper, a recording material such as cloth and leather can be used.

Next, the toner contains at least a soft magnetic material and a magnetic attraction reducing component.

First, a soft magnetic material does not show the behavior of a magnet when an external magnetic field is removed, and specifically means a material having a small maximum energy product BHmax of the magnetic material. The standard is BHmax ≦ 5 (KJ
/ M ³ ). When BHmax is unknown, simplified formula

[0017]

(Equation 1)

(Where Br is the residual magnetic flux density [T], Hc
Is the approximate value of the coercive force [AT / m]). Specific examples include magnetite and ferrite. Among them, a soft magnetic material having a maximum energy product of 5 (KJ / m ³ ) or less is preferable. In addition, remanent magnetization 100 emu /
g or less of a soft magnetic material is preferable. Furthermore, holding force 200 Oe
The following soft magnetic materials are preferred. Further, a soft magnetic material having all of these residual magnetization and coercive force is preferable.

These soft magnetic materials preferably have a size of 1 μm or less.

The term "magnetic attraction reducing component" means a component which can suppress magnetic coupling between toners and between the toner and the fixing means. Specifically, waxes such as polypropylene wax, polyethylene wax, liquid paraffin, acid amide wax, stearic acid wax, montan wax, sasol wax, caster wax, chlorinated paraffin and carnauba wax can be used.

The soft magnetic material and the magnetic attraction reducing component vary depending on the kind thereof, but each of the soft magnetic material and the magnetic attraction component is contained in the toner.
-30% by weight and 0.5-5% by weight. On the other hand, if the magnetic attraction reducing component is less than 0.5% by weight, it is not preferable because the reduction is insufficient and offset may occur. If it is more than 5% by weight, filming on the photoreceptor (WAX adhesion) ) Is liable to occur.

The toner may contain known components other than the soft magnetic material and the magnetic attraction reducing component. Examples of such components include a binder resin, a colorant, and a charge control agent. Further, a known external additive may be added to the toner.

As the binder resin, a copolymer of styrene and its substituent or an acrylic resin which has been conventionally used as a binder resin for a toner can be used.

Examples of the copolymer of styrene and its substituted product include polystyrene homopolymer, hydrogenated styrene resin, styrene-isobutylene copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene-styrene terpolymer. Acrylonitrile-styrene-acrylic ester terpolymer, styrene-acrylonitrile copolymer, acrylonitrile-acrylic rubber-styrene terpolymer, acrylonitrile-chlorinated polystyrene-styrene terpolymer, acrylonitrile-EVA- Styrene terpolymer, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer,
Examples thereof include styrene-butadiene rubber, styrene-maleic acid ester copolymer, styrene-isobutylene copolymer, and styrene-maleic anhydride copolymer.

As the acrylic resin, for example,
Polyacrylate, polymethyl methacrylate, polyethyl methacrylate, poly-n-butyl methacrylate, polyglycidyl methacrylate, polyfluorinated acrylate, styrene-acrylic acid copolymer, styrene
Examples thereof include a methacrylate copolymer, a styrene-butyl methacrylate copolymer, and a styrene-ethyl acrylate copolymer.

Other binder resins include polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, phenol resin, urea resin, polyvinyl butyral, polyacrylic resin, rosin, modified rosin, Terpene resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be used alone or in combination.

Alcohol monomers among the monomers used to form the polyester include, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol,
Diols such as 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A And bisphenol A alkylene oxide adducts such as polyoxyethylenated bisphenol A, polyoxypropylene bisphenol A, and other dihydric alcohols.

Among the monomers used to form the polyester, the acid monomers include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, Succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, or alkenylsuccinic acids or alkylsuccinic acids such as n-dodecenylsuccinic acid, n-dodecylsuccinic acid, anhydrides of these acids,
Examples thereof include alkyl esters and other divalent carboxylic acids.

Specific examples of the charge control agent include metal-containing azo dyes such as “Varifast Black 3804”,
"Bontron S-31", "Bontron S-32",
Metal complexes of copper phthalocyanine dyes, alkyl derivatives of salicylic acid, such as "Bontron S-34", "Bontron S-36" (hereinafter, manufactured by Orient Chemical Co., Ltd.), "Eizen Spiron Black TRH" (manufactured by Hodogaya Chemical Co., Ltd.), for example, "Bontron E-82", "Bontron E-84",
"Bontron E-85" (hereinafter, manufactured by Orient Chemical Co., Ltd.)
And others (for example, N-04 manufactured by Orien Kogyo KK).

Various coloring materials are used. For example, the yellow colorant includes nitro-based pigments such as naphthol yellow S, Hansa Yellow 5G,
Examples include azo pigments such as Hansa Yellow 3G, Hansa Yellow G, Benzidine Yellow GR, Benzidine Yellow G, and Vulcan Fast Yellow 5G, and inorganic pigments such as yellow iron oxide and loess. As the dye, C.I. described in the color index is used. I. Solvent Yellow 2, C.I. I. Solvent Yellow 6, C.I. I. Solvent Yellow 14, C.I. I. Solvent Yellow 15,
C. I. Solvent Yellow 16, C.I. I. Solvent Yellow 19, C.I. I. And oil-soluble dyes such as Solvent Yellow 21.

The magenta coloring material is C.I. I.
Pigment 122, C.I. I. Pigment Violet 1
Quinacridone pigments such as Rhodamine 6G lake, Rhodamine B lake, C.I. I. Rhodamine pigments such as CI Pigment Red 81; I. Pigment Red 87,
C. I. Bio Red 1, C.I. I. Pigment Bio Red 38 and the like; azo pigments such as Brilliant Carmine 6B and Lisorrubin GK; I. Solvent Red 49, C.I. I. Solvent Red 19, C.I. I. There are oil-soluble dyes such as Solvent Red 52.

Cyan colorants include phthalocyanine blue, heliogen blue G, fast sky blue, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 17, C.I.
I. Pigment Green 7, C.I. I. Pigment Green 12, C.I. I. Pigment Green 36, C.I. I. Pigment Green 37, C.I. I. Pigment Green 3
Phthalocyanine pigments such as C.8; I. Solvent Blue 25, C.I. I. Solvent Blue 55, C.I.
I. Solvent Blue 70, C.I. I. Solvent Blue 40, C.I. I. Direct Blue 25, C.I. I. There are oil-soluble dyes such as Direct Blue 86.

As a black coloring material, a thermal black method,
There are various carbon blacks produced by an acetylene black method, a channel black method, a furnace black method, a lamp black method and the like.

The above-mentioned dyes and pigments modified can be used, and two or more kinds can be blended and used.

Here, the colorant and the antistatic agent are, for example, 2 to 100 parts by weight of the binder resin, respectively.
It can be used in proportions of 20 parts by weight and 5 parts by weight or less.

As the external additive, silica fine particles, metal oxide fine particles, a cleaning aid and the like are used.

Examples of the silica fine particles include silicon dioxide, aluminum silicate, sodium silicate, zinc silicate and magnesium silicate.

Examples of the metal oxide fine particles include zinc oxide, titanium oxide, aluminum oxide, zirconium oxide, strontium titanate, and barium titanate.

Examples of the cleaning aid include fine resin powders such as polymethyl methacrylate, polyvinylidene fluoride, and polytetrafluoroethylene.

These external additives may have been subjected to a surface treatment such as hydrophobization.

The toner of the present invention preferably has an average particle size of 5 to 15 μm.

The method for producing the toner is not particularly limited, and any known method can be used. For example, there is a method of mixing and dispersing the raw materials of the toner, and then pulverizing the raw materials to form a predetermined size.

Examples of the mixing / dispersing means include a wet dispersing method such as a high-speed dissolver, a roll mill and a ball mill, a melt kneading method using a roll, a pressure kneader, an internal mixer, a screw type extruder, a ball mill, and a V-type mixer. ,
A Folberg, Henschel mixer or the like can be used.

As means for crushing the mixture, for example,
Hammer mills, cutter mills, roller mills, ball mills and the like can be used. The pulverized product may be finely pulverized using a jet mill, a high-speed rotary pulverizer, or the like.

It is preferable that the pulverized material is classified into a predetermined size. As a means for classifying the pulverized material, an air flow classifier or the like can be used.

[0046]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 The following materials were used as raw materials for a toner.・ Styrene-acrylic acid copolymer 100 parts by weight (SPR1500 manufactured by Sanyo Kasei Co., Ltd., molecular weight: Mn 7.6 × 10 ³ , Mw 2.2 × 10 ⁵ , Tg: 63.0 ° C.) ・ Carbon black 7 parts by weight (Cabot) 2 parts by weight of polypropylene wax (manufactured by Sanyo Kasei Co., Ltd.) 2 parts by weight of charge control agent (N-04 manufactured by Orien Kogyo) 20 parts by weight of magnetite (EPT-500 manufactured by Toda Kogyo Co., Ltd., saturation magnetization 59. 4 emu / g, residual magnetization 10.4 emu / g, coercive force 122 Oe)
Premixed at 0 rpm for 2 minutes. Next, the obtained mixture was put into a twin-screw kneading extruder (PCM60 manufactured by Ikegai Co., Ltd.), extruded while mixing at 250 rpm and a discharge rate of 110 kg / h, and then formed into pellets.

The obtained pellets were crushed using a pulverizer (Jet Mill manufactured by Nippon Pneumatic Corporation) at a frequency of 50H.
Milled for 1.2 minutes at z. The obtained pulverized product was subjected to a classifier to obtain a toner having an average particle size of 7 μm.

The fixing property of the obtained toner with respect to the fixing temperature was observed using a fixing device having the structure shown in FIG. The recording paper used was copy paper SF-4AM manufactured by Sharp Corporation.
2 was used. The fixing belt has a resin thickness of 0.2 m in which 20 parts by weight of the same magnetite as the toner is dispersed.
m belts were used. Table 1 shows the results. In Table 1, △
Means low-temperature offset, ○ good, × high-temperature offset.

Comparative Example 1 A toner was obtained in the same manner as in Example 1 except that no polypropylene wax was used. Using the obtained toner, fixing property was observed in the same manner as in Example 1. Table 1 shows the results
Shown in

Comparative Example 2 Magnetite was hard ferrite (saturated magnetization of 58 emu)
/ G, residual magnetization 20.5 emu / g, coercive force 1550O
A toner was obtained in the same manner as in Example 1 except that e) was replaced. Using the obtained toner, fixing property was observed in the same manner as in Example 1. Table 1 shows the results.

[0052]

[Table 1]

As can be seen from Table 1, the toner of the present invention shows good fixability over a wide fixing temperature range.

[0054]

According to the toner of the present invention, at the time of fixing, the toner is scattered under the influence of the magnetic field, so that the image is not disturbed and the magnetic coupling between the toners and the toner and the fixing means can be reduced. Therefore, occurrence of offset can be suppressed.
Therefore, a stable and excellent image with high image quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus using a toner of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording material 2 Toner 3 Fixing belt 4 Induction heating coil 5 Pressure roller

Claims (3)

[Claims] 1. An induction heating fixing toner which is used in an induction heating fixing device having a fixing means containing a magnetic material and comprises at least a soft magnetic material and a magnetic attraction force reducing component. 2. The toner according to claim 1, wherein the soft magnetic material is magnetite or ferrite. 3. The magnetic attraction reducing component is polypropylene wax, polyethylene wax, liquid paraffin, acid amide wax, stearic acid wax, montan wax, sasol wax, caster wax, chlorinated paraffin or carnauba wax. 1 or 2
The toner according to 1.