JPH04328581A - Method for thermal fixing and toner for thermal fixing - Google Patents

Abstract

PURPOSE:To achieve excellent fixation and offset resistance performance, to make a waiting time short and to achieve high durability. CONSTITUTION:As for a method for thermally fixing the developed image of toner 20 on a recording material 19, the shape of the toner 20 is 0.95-1.00 in the practical spheroidicity psiw of Wadell. By a fixed and supported heating body 11 and a pressuring member 18 which is faced and made to press-contact with the heating body 11 and which makes the recording material 19 adhere to the heating body 11 through a film 15, the developed image of the toner 10 is thermally fixed on the recording material 19.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to electrophotography, electrostatic printing,
In magnetic recording, etc., the visible image formed with toner is
The present invention relates to a fixing method for fixing onto a recording material and a toner used in the fixing method.

0002

[Prior Art] Conventionally, as a method for fixing a toner image on a recording material, a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer and pressed against the heating roller are used. A hot roll fixing method is often used in which a recording material holding a toner image is heated while being sandwiched and conveyed.

A belt fixing system described in US Pat. No. 3,578,797 is also known.

However, in the above-mentioned hot roll fixing which has been widely used in the past, there is (1) a so-called wait time, which is a period during which the image forming operation is prohibited until the hot roller reaches a predetermined temperature. (2) Maintain the heating roller at an optimal temperature to prevent fixation failure and toner transfer to the heating roller, the so-called offset phenomenon, due to fluctuations in the temperature of the heating roller due to passage of the recording material or other external factors. For this purpose, the heat capacity of the heating roller or heating body must be increased, which requires a large amount of electric power. (3) Since the temperature of the roller is low, when the recording material passes through the heated roller and is discharged, the recording material and the toner on the recording material are cooled slowly, resulting in a highly sticky state of the toner, and the roller Coupled with the curvature of the recording material, paper jams may occur due to offset or entrainment of the recording material. (4) The high-temperature heating roller is directly touched by the hands, which may pose a safety problem or require a protective member.

[0005] Also, the belt fixing method described in US Pat.
1) and (2) have not been fundamentally resolved.

[0006] Also, the present applicant previously proposed JP-A-62-
In Japanese Patent No. 147884, a fixing device that heats a toner image via a moving heat-resistant sheet and fixes it onto a recording material using a low heat capacity heating element that generates heat through electricity in a pulsed manner shortens the wait time and reduces power consumption. Image forming apparatuses have been proposed. Similarly, in JP-A-63-12069, which was previously proposed by the present applicant, in a fixing device that heats and fixes a toner image onto a recording material via a heat-resistant sheet, the heat-resistant sheet is heat-resistant. A fixing device that effectively prevents the offset phenomenon by having a release layer or a low resistance layer has been proposed.

[0007]

[Problems to be Solved by the Invention] However, it is desirable to realize a fixing method that achieves excellent fixation of toner images on recording materials and offset resistance, short wait time, and low power consumption. In order to achieve durability, in addition to the above-mentioned fixing device, a large amount depends on the characteristics of the toner.

That is, an object of the present invention is to solve the above-mentioned problems, and to achieve substantially no or very short wait time, low power consumption, no offset phenomenon, and toner transfer to a recording material. The present invention provides a novel heat fixing method that can fix images well and achieve high durability.

Another object of the present invention is to provide a toner for heat fixing that is preferably used in the heat fixing method provided in the present invention.

0010

[Means and effects for solving the problem] The present inventors have
As a result of intensive studies from various angles in order to achieve the above-mentioned purpose, we found that the shape of the toner is 0.95 in terms of Wardell's practical sphericity Ψw in the method of heating and fixing the toner image on the recording material. ~1.00, and is characterized by a fixedly supported heating body and a pressure member that faces and presses against the heating body and brings the recording material into close contact with the heating body through a film. It has been found that this can be achieved by a heat fixing method characterized by heat fixing a visible image of the toner onto a recording material.

The heat fixing process of the present invention applicable to the heat fixing method described above will be specifically explained below.

FIG. 1 shows a structural diagram of a fixing device according to the present invention.

Reference numeral 11 denotes a low heat capacity linear heating element fixedly supported by the device, and has a thickness of 1.0 mm and a width of 10 m, for example.
m, resistance material 1 on alumina substrate 12 with a longitudinal length of 240 mm.
3 coated to a width of 1.0 mm, and electricity is applied from both ends in the longitudinal direction. Power supply is DC 100V with a cycle of 20msec.
A pulse corresponding to the desired temperature and energy release amount controlled by the temperature measuring element 14 is given by changing the pulse width with a pulse-like waveform. Approximate pulse width is 0.5ms
ec~5msec. The fixing film 15 moves in the direction of the arrow in the figure while coming into contact with the heating body 11 whose energy and temperature are controlled in this way.

When the temperature detected by the temperature detection element 14 in the low heat capacity linear heating element 11 is T1, the surface temperature T2 of the film 15 facing the resistance material 13 is approximately equal to T1. Further, the film surface temperature T3 at the portion where the film 15 is peeled off from the toner fixing surface is approximately equal to the temperatures T1 and T2.

[0015] In the present invention, the heating body has a smaller heat capacity than a conventional heating roll and has a linear heating section, and the maximum temperature of the heating section is preferably 100 to 300°C.

[0016] The film located between the heating member and the pressure member is preferably a heat-resistant sheet with a thickness of 1 to 100 μm, and these heat-resistant sheets include highly heat-resistant polyester, PET (polyethylene terephthalate), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (
In addition to polymer sheets such as polytetrafluoroethylene), polyimide, and polyamide, metal sheets such as aluminum and laminate sheets composed of metal sheets and polymer sheets are used.

[0017] A more preferable film structure is that these heat-resistant sheets have a release layer and/or a low resistance layer, and a specific example is a release layer made of a fluororesin with a conductive material added. It is an endless film coated with

Here, the film is driven by a drive roller 16.
Driven by the driven roller 17 and tension, it moves in the direction of the arrow without wrinkles.

Reference numeral 18 denotes a pressure roller having a rubber elastic layer with good mold releasability such as silicone rubber, which presses the heating body through the film at a total pressure of 4 to 20 kg and rotates in pressure contact with the film. The unfixed toner 20 on the transfer material 19 is guided to the fixing section by the entrance guide 21, and a fixed image is obtained by the above-mentioned heating.

[0020] The above was explained using an endless belt, but FIG.
As shown in FIG. 2, the sheet feeding shaft 22 and the winding shaft 23 may be used, and the fixing film may be a film with ends.

Further, as an image forming apparatus, the present invention is applicable to a fixing device of any apparatus that forms an image using toner, such as a copying machine, a printer, and a facsimile machine.

Next, a developer applicable to the image forming method of the present invention will be explained.

The developer according to the present invention is characterized in that the shape has a Wardel's practical sphericity Ψw of 0.95 to 1.00. Wardell's practical sphericity Ψw mentioned here is

[0024]

[Math 1] This is the value expressed as .

Since the developer of the present invention has the above-described structure, scratches and abrasions on the surface of the fixing film, as well as contamination and adhesion, are extremely unlikely to occur.

From the above, the developer according to the present invention is
It has been found that it is possible to provide a heat fixing method that fully utilizes the capability of the fixing process according to the present invention and always performs good heat fixing.

The present inventors believe that the reason why the developer according to the present invention exhibits the above effects is as follows. That is, in powder particles having flat portions, adsorption occurs between the planes, and higher energy is required to separate the bonds than when the particles are in contact with each other on curved surfaces. Therefore, by increasing the sphericity of the developer, the adhesive force of the developer is reduced by reducing the area of contact with the fixing sheet against mechanical pressure and sliding on the toner fixing surface. It is estimated that this prevents scratches and scrapes caused by rubbing on the surface of the fixing sheet, as well as dotted or linear sticking phenomena caused by this.

The toner according to the present invention is generally produced as follows. ■Uniformly disperse the binder resin, optionally magnetic material, and dyes and pigments as coloring agents using a mixer such as a Henschel mixer. (2) Melt and knead the dispersion obtained above using a kneader, extruder, roll mill, etc. ■After coarsely pulverizing the kneaded material with a cutter mill, hammer mill, etc., finely pulverizing it with a jet mill, etc. ■The finely pulverized material is classified using a zigzag classifier to make the particle size distribution uniform. (2) The classified powder obtained above is atomized by being discharged with compressed air from a nozzle into a hot air stream using a spray dryer or the like, and then cooled or dried to obtain a toner.

[0029] Other toner manufacturing methods that can be used include a polymerization method and a capsule method. An outline of these manufacturing methods will be described below.

(Polymerized toner) (1) A polymerizable monomer, if necessary a polymerization initiator, a colorant, etc. are granulated in an aqueous dispersion medium. (2) Classifying the granulated monomer composition particles into appropriate particle sizes. (2) Polymerizing the monomer composition particles having a specified particle size obtained by the above classification. (2) After removing the dispersant through appropriate treatment, the polymerization product obtained above is filtered, washed with water, and dried to obtain a toner.

(Capsule Toner) (2) A resin and, if necessary, magnetic powder are kneaded using a kneader or the like to obtain a toner core material in a molten state. ■Pour toner core material into water and stir vigorously to create fine particle core material. (2) Put the core material fine particles into the shell material solution, drop a poor solvent while stirring, and encapsulate the core material by covering it with the shell material. (2) The capsules obtained above are filtered and dried to obtain a toner.

(Spray method toner) (2) A binder resin, optionally a magnetic material, dyes and pigments as a coloring agent, etc. are kneaded in a kneader or the like, cooled, pulverized, and then classified to obtain a toner core material. ■ Strongly stir the fine powder of resin or polymer material into the toner core material to uniformly disperse it. (2) The dispersion obtained above is atomized by being discharged with compressed air from a nozzle into a hot air stream using a spray dryer or the like, and then cooled or dried to obtain a toner.

The binder resin of the toner according to the present invention is as follows:
Monopolymers of styrene and its substituted products such as polystyrene and polyvinyltoluene; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate copolymers, styrene- Ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-methacrylate ethyl ester copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-
Vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic copolymer Styrenic copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, polyacrylic acid resins,
Rosin, modified rosin, terpene resin, phenolic resin,
Aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin,
Paraffin wax, carnauba wax, etc. can be used alone or in combination.

In particular, as the binder resin in the core material of the capsule toner, generally known materials can be used, but pressure fixing or low temperature fixing toners commonly used as microcapsule toners are not suitable. ,
Soft solid materials are preferably used. Such substances include waxes (beeswax, carnauba wax, paraffin wax, microcrystalline wax, etc.)
, higher fatty acids (stearic acid, palmitic acid, lauric acid, etc.), higher fatty acid metal salts (aluminum stearate, lead stearate, barium stearate, magnesium stearate, zinc stearate, zinc palmitate, etc.), higher fatty acid derivatives ( methyl hydroxystearate, glycerol monohydroxystearate, etc.), polyolefins (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, polyisobutylene, polytetrafluoroethylene, etc.), olefin copolymers (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer resin, etc.), styrene resin (Low molecular weight polystyrene, styrene-butadiene copolymer (monomer weight ratio 5-30:95-70), styrene-acrylic compound copolymer, etc.), epoxy resin, polyester resin (acid value 10 or less), rubber ( (isobutylene rubber, nitrile rubber, chloride rubber, etc.), polyvinylpyrrolidone, polyamide, coumaron-indene resin, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, silicone resin, etc. They can be used alone or in combination.

The crosslinking agent used in the toner of the present invention includes divinylbenzene, bis(
4-acryloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-diallyl phthalate, triallyl cyanurate, triallyl asocyanurate, triallyl isocyanurate, triallyl trimellitate , diarylchlorentate, etc.

When producing the resin of the present invention or obtaining a toner by a polymerization method, selection of the initiator, type of solvent, and reaction conditions are important factors in obtaining the objective resin of the present invention.

The polymerization initiator is generally a compound that generates radicals when decomposed by heat or light, and examples of the azobisnitrile type include 2,2'-azobisisobutyronitrile and 2,2'-azobispropylene. pionitrile, 2,2
'-azobisvaleronitrile, 2,2'-azobis-(
Examples include 2,4-dimethyl)valeronitrile.

Examples of organic peroxides include benzoyl peroxide, nuclear substituted benzoyl peroxide, lauroyl peroxide,
Examples include acetyl peroxide, cumene hydroperoxide, etc.

Examples of azo and diazo compounds include diazoaminobenzene and azothioether.

Examples of sulfins include aromatic sulfinic acids.

When producing the developer of the present invention by a polymerization method, a stabilizer may be added to the reaction solution as long as it does not have a substantial adverse effect. Specific examples include poorly soluble fine powder inorganic compounds, such as BaSO4
, CaSO4, MgCO3, BaCO3, CaCO3,
Slightly soluble salts such as Ca3(PO4)2, diatomaceous earth, talc, silicic acid, clay, inorganic polymers such as talc, powders of metal oxides, water-soluble polymers such as polyvinyl alcohol, gelatin, starch, methyl cellulose, Examples include ethyl cellulose, carboxymethyl cellulose, polyacrylic acid and their salts, alginates, and the like. These stabilizers are normally used in an amount of 0.1 to 10% by weight.

A surfactant may also be used in an amount of 0.001 to 0.1% by weight for fine dispersion of the hardly soluble, finely powdered inorganic compound.

Examples of surfactants used for such purposes include anionic surfactants such as sodium dodecylbenzene sulfonate, sodium allyl-alkyl polyether sulfonate, sodium oleate, polyoxyethylene alkyl ether, Nonionic surfactants such as oxyethylene alkyl allyl ether are commonly used.

As the colorant contained in the developer according to the present invention, generally known dyes and pigments can be used. Examples of such dyes and pigments include carbon black, nigrosine dye, lamp black, and sudan black SM.
, First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgazine Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Permanent Bordeaux FR
R, Pigment Orange R, Resole Red 2G,
Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B,
Phthalocyanine Green, Oil Yellow GG, Zapon First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiplast Yellow GG, Zapon First Orange RR, Oil Scarlet, Sumiplast Orange G, Orazole Brown B, Zapon First Scarlet CG, Eisenspiron Red B
EH, oil pink OP, etc. can be applied. These colorants are generally used to obtain capsule toners for two-component developers, and are preferably added at a rate of 5 to 20% to the core binder.

The magnetic fine particles contained in the toner of the present invention include metals made of ferromagnetic elements such as iron, cobalt, and nickel, including ferrite and magnetite;
or alloys or compounds containing these, or alloys that do not contain ferromagnetic elements but become ferromagnetic through appropriate heat treatment, such as manganese-copper-aluminum or manganese-copper-tin, etc. and copper, or chromium dioxide, among others. The content ratio of the fine powder of these magnetic substances can be 30 to 150 parts by weight, preferably 40 parts by weight, based on 100 parts by weight of the binder resin.
~100 parts by weight.

As the charge control agent contained in the toner according to the present invention, a conventionally known charge control agent is selected. As a specific example of a positive charge control agent, generally nigrosine, carbon number 2
Azine dyes containing ~16 alkyl groups (Special Publication No. 1973-
1627), basic dyes (e.g. C.I.Basic
Yellow 2 (C.I.41000), C.I.
I. Basic Yellow 3,C. I. Ba
sic Red 1 (C.I.45160), C.I.
I. Basic Red 9 (C.I.42500
), C. I. Basic Violet 1 (C.
I. 42535), C. I. Basic Viole
t 3 (C.I.42555), C. I. Basic
Violet 10 (C.I.45170), C.I. I
．． Basic Violet 14 (C.I.42
510), C. I. Basic Blue 1 (C
．． I. 42025), C. I. Basic Blue
3 (C.I.51005), C. I. Basic
Blue 5 (C.I.42140), C.I. I. B
asic Blue 7 (C.I.42595),
C. I. Basic Blue 9 (C.I.52
015), C. I. Basic Blue 24 (
C. I. 52030), C. I. Basic Blue
e 25 (C.I.52025), C. I. Basi
c Blue 26 (C.I.44025), C.I.
I. BasicGreen 1 (C.I.42040
), C. I. Basic Green 4 (C.I.
．． 42000), lake pigments of these basic dyes (lake-forming agents include phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.) ,C. I. Sovent Black
3 (C.I.26150), Hansa Yellow G (C
．． I. 11680), C. I. Mordlant B
Lack11,C. I. Pigment Black
1st prize.

Alternatively, polyamine resins such as quaternary ammonium salts such as benzolmethyl-hexadecyl ammonium chloride and decyl-trimethyl ammonium chloride, vinyl polymers containing amino groups, condensation polymers containing amino groups, etc. may be mentioned. ,
Preferred examples include nigrosine, quaternary ammonium salts, triphenylmethane-based nitrogen-containing compounds, and polyamines.

[0048] Specific examples of negative charge control agents include Japanese Patent Publications Nos. 41-20153, 42-27596, and 44
-6397, metal complex salts of monoazo dyes described in JP-A No. 45-26478, as well as JP-A-50-
Nitrohumic acid and its salts or C.I. I. Zn of salicylic acid, naphthoic acid, and dicarboxylic acid described in dyes and pigments such as No. 14645; , metal complexes such as Al, Co, Cr, Fe,
Examples include sulfonated copper phthalocyanine pigments, nitrile groups, styrene oligomers into which halogens have been introduced, and chlorinated paraffins. Especially from the aspect of dispersibility,
Preferred are metal complexes of monoazo dyes, metal complexes of salicylic acid, alkylsalicylic acid, naphthoic acid, and dicarboxylic acid. The amount of these charge control agents added is determined so as to maintain good triboelectric charging properties as described above, while minimizing adverse effects such as a decrease in developing power and a decrease in environmental stability due to contamination of the surface of the developing sleeve by the charge control agent. In order to suppress the amount, the amount added is preferably 0.1 to 3 parts by weight per 100 parts by weight of the binder resin.

The developer of the present invention may further contain other additives as long as they do not have a substantial adverse effect. Specific examples thereof include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide, silicon carbide, and strontium titanate, flow agents such as colloidal silica and aluminum oxide, anti-caking agents, and e.g. Examples include conductivity imparting agents such as carbon black, zinc oxide, antimony oxide, and tin oxide, fixing aids such as low molecular weight polyethylene, low molecular weight polypropylene, various waxes, and anti-offset agents. Further, a small amount of white fine particles and black fine particles of opposite polarity can be used as a developing property improving agent.

All known methods can be used to develop this toner. For example, two-component development methods such as cascade method, magnetic brush method, and microtoning method; one-component development methods containing magnetic materials such as conductive one-component development method, insulating one-component development method, and jumping development method; powder Examples include cloud method and fur brush method; non-magnetic one-component development method in which toner is held on a toner carrier by electrostatic force and transported to a developing section for development.

The basic structure and features of the present invention have been described above, and the method of the present invention will be specifically explained below based on examples. However, this does not limit the embodiments of the present invention in any way.

[0052]

[Example] Example-1 Magnetic particles (magnetite, bulk density = 1.10 g/c
m3) 60 parts by weight Styrene-n-butyl acrylate copolymer
100 parts by weight (copolymerization weight ratio 8:2, Mw
= 220,000) Negative charge control agent (monoazo dye-based chromium complex) 1 part by weight Low molecular weight polypropylene (Mw = 6,000)
3 parts by weight The above mixture was melt-kneaded with a twin-screw extruder heated to 140°C, the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was pulverized with a jet mill to obtain a finely pulverized product. The powder was classified by air to obtain a classified powder with a volume average particle diameter of 12 μm.

Next, this classified powder was used to obtain a spherical toner using a spray dryer (manufactured by Mitsubishi Kakoki).

This toner was substantially spherical, and its Wardell practical sphericity was 0.96 as the average value of 100 toner particles.

Next, hydrophobic colloidal silica was mixed with this spherical toner using a Henschel mixer to obtain a developer.

Next, in the heat fixing device of the present invention shown in FIG. The total pressure between the pressure roller 21 and the pressure roller 21 is 13 kg, the nip between the pressure roller and the film is 3 mm, and the fixing film 1
The rotation speed of No. 8 was set to 48 mm/sec using an image forming device (Canon laser beam printer LBP-SX).
2,000 consecutive times to form toner images using a modified machine)
A live-action test was conducted. At this time, as the fixing film, a 20 μm thick polyimide film having a low-resistance release layer made of PTFE with a conductive substance dispersed thereon on the contact surface with the recording material was used. As a result, the time required for the surface temperature T1 of the temperature measuring element of the heating body to reach 183° C. was about 3 seconds. Further, temperature T2 was 180°C, and temperature T3 was 179°C.

After the actual photographic test, no residual developer stuck to the surface of the fixing film, and there were almost no scratches or scrapes, indicating good durability. Further, no offset phenomenon was observed in the obtained image, and the fixing properties were also sufficient.

Example-2 Polyethylene wax (softening point 120°C)
100 parts by weight magnetite

80 parts by weight The above mixture was kneaded using a roll mill, cooled, pulverized, and then classified to obtain a colored fine powder of 10 to 25 microns.

On the other hand, Petrocoat RJ1200 (composition name: oxidized starch, softening point: 140°C, trade name, Nippon Deka Chemical Industry Co., Ltd.) powder is further finely pulverized and classified to have a powder of 0.1 μ to 1 μm.
A powder of μ was obtained.

Next, 10 parts by weight of the classified fine powder of Petrocoat was mixed with 100 parts by weight of the colored fine powder in a Henschel mixer for 1 minute.
Toner was obtained by atomizing into a hot air stream (inlet 200°C, outlet 100°C, difference in air pressure between inlet and outlet 50 mm water column) except for changing the nozzle pressure to 1 kg/cm 2 in the 604 system.

The Wardell practical sphericity of this toner was 0.97 as an average value of 100 toner particles.

When the surface of this toner was observed using an electron microscope, it was found that the colored fine powder particles were uniformly coated with the Petrocoat fine powder, which was partially embedded, and the particles were firmly adhered to each other.

Next, hydrophobic colloidal silica was mixed with this spherical toner using a Henschel mixer to obtain a developer.

Next, this developer was heated at a temperature of 190° C. on the surface of the temperature measuring element of the heating element 11 and at a rotational speed of 1.
An image forming apparatus (a modified Canon electronic copying machine NP-120) having a heat fixing device which was set in the same manner as in Example 1 except that the speed was set to 40 mm/sec was used, and the toner was A live photo test was conducted on 2,000 consecutive images. As a result, there was no residual developer sticking to the fixing film, and the fixing film exhibited good durability with almost no scratches or scrapes, and a sufficiently fixed image was obtained without any offset phenomenon.

Example-3 Styrene
180 parts by weight n-butyl acrylate
20 parts by weight
divinylbenzene
1 part by weight
Azobisisobutyronitrile
7 parts by weight Heliogen Blue L-7080 (manufactured by BASF) 10
Weight parts First Gen Blue NK (manufactured by Dainippon Ink Co., Ltd.) 5 parts by weight were added to T. K homo mixer (
The mixture was uniformly mixed for about 5 minutes in a container equipped with a high shear mixer (manufactured by Tokushu Kogyo Co., Ltd.). During this time, the temperature was maintained at 70°C. 2 parts by weight of polyvinyl alcohol was dispersed in 800 parts by weight of water using the homomixer described above, and the mixture was maintained at 70°C. In this system, T. The above slurry was added under stirring using a K homo mixer, and stirred at about 4000 rpm for about 40 minutes. Thereafter, this reaction mixture system was stirred with paddle blade stirring to complete the polymerization. A toner was obtained by washing with water, filtering, and drying. The Wardell practical sphericity of this toner was 0.98 as an average value of 100 toner particles. This toner and iron powder carrier 250/400 (Japan Iron Powder) were mixed at a weight ratio of 10:100 to prepare a developer.

Next, this developer was used in the heat fixing device of the present invention as shown in FIG. 2, and the rotation speed of the fixing film was set to 100 mm/
An image forming apparatus (Canon electronic copying machine NP
-1215 modified machine), we conducted a continuous 2,000-shot live-action test. As a result, no residual developer stuck to the fixing film, and no scratches or scrapes were observed.

Further, during fixing, there was no offset phenomenon at all, and even when the set temperature was lowered by 10° C. than before, sufficient fixing was achieved.

Example-4 Paraffin wax
95 parts by weight diethylaminomethyl methacrylate polymer
5 parts by weight magnetic powder

80 parts by weight carbon black

3 parts by weight The above mixture is melted and dispersed at 100° C. for 2 hours using an attritor (manufactured by Mitsui Miike Co., Ltd.) filled with stainless steel balls to obtain a molten mixture of dispersoids.

Separately, 16 liters of water was placed in a 20 liter Ajihomo mixer (manufactured by Tokushu Kika) and heated and maintained at 90°C. 80 parts by weight of colloidal silica, Aerosil #300 (manufactured by Nippon Aerosil Co., Ltd.), was added thereto and uniformly dispersed by stirring. Thereafter, the molten mixture is heated to 110° C. and placed in an Ajihomo mixer. After the addition of the molten mixture, the dispersion medium containing the suspended dispersoid particles was discharged into ice water, and the dispersoid particles were rapidly cooled and solidified into substantially spherical particles. After the temperature was returned to room temperature, 400 parts by weight of sodium hydroxide was added and stirred with a propeller mixer to dissolve the colloidal silica. This dispersion was filtered using a centrifuge, washed with water, and dried.
After crushing the obtained core material, it was used as a core material for encapsulation.

Styrene-diethylaminoethyl methacrylate (95:5) copolymer (Mw about 12,000) 2
A resin solution was prepared by dissolving 0 part by weight in 380 parts by weight of N,N dimethylformamide. After 5.6 kg of the above solution was put into the encapsulation reaction tank and cooled to -25°C, 215 g of acetic acid was added and stirred for several minutes. When 2 kg of the core material was added and stirred for 10 minutes, the core material was uniformly dispersed in the solution. After adding cold water to precipitate the resin, the dispersion was taken out from the reaction tank, and the solid content and solvent were separated using a centrifugal filter. This solid content was washed with water, further centrifugally filtered, and then dried in a ventilation dryer. This dried colloidal silica was externally added using a Henschel mixer to form a microcapsule toner. The Wardell practical sphericity of this toner was 0.97 as an average value of 100 toner particles.

Next, this developer was used as an image forming apparatus (manufactured by Canon Co., Ltd.) having a heat fixing device set in the same manner as in Example 1, except that the heat fixing device shown in FIG. A continuous photocopy test of 1,000 sheets was conducted using an electronic copying machine (PC-30 (modified model)). As a result, no residual developer stuck to the fixing film. Further, no offset phenomenon was observed in the obtained image, and the fixing properties were also sufficient.

[0072]

As explained above, the present invention prevents scratches and abrasions on the surface of the fixing sheet caused by the developer, as well as the sticking of residual toner caused by these, thereby providing excellent fixing performance and anti-offset properties. While achieving this, the wait time is short,
We were able to realize a fixing method that consumes low power and also achieves high durability.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing a heat fixing device of the present invention.

FIG. 2 is an explanatory diagram schematically showing a heat fixing device equipped with a fixing film winding device according to another embodiment of the present invention.

[Explanation of symbols]

11 Heating body 12 Alumina substrate 13 Resistance material 14 Temperature measurement element 15 Fixing film 16 Drive roller 17 Driven roller 18 Pressure roller 19 Recording material 20 Unfixed toner 21 Entrance guide 22 Sheet feed shaft 23 Winding shaft

Claims (2)

[Claims] 1. A method of heating and fixing a toner image on a recording material, characterized in that the shape of the toner has a Wardel practical sphericity Ψw of 0.95 to 1.00. The visible image of the toner is heated and fixed on the recording material by a fixedly supported heating body and a pressure member that is in opposing pressure contact with the heating body and brings the recording material into close contact with the heating body through a film. A heat fixing method characterized by: 2. A toner image is heated on a recording material by a fixedly supported heating body and a pressure member that is in pressure contact with the heating body and brings the recording material into close contact with the heating body through a film. In the toner used in the fixing method,
At least the shape of the toner has Wardell's practical sphericity Ψw
A toner for heat fixing, characterized in that: 0.95 to 1.00.