JPH0467045A - Toner for electrostatic charge development and its fixing method - Google Patents

Abstract

PURPOSE:To improve low-temperature fixing performance and low-temperature offsetting resistance by suing such toner that a heat absorption peak by a binding resin component and a heat absorption peak by releasing agent component do not overlap each other. CONSTITUTION:Toner is formed by suspending and polymerizing a polymerizing monomer system which contains at least a releasing agent and a coloring agent in water-based medium and the contact angle of pellets, formed by compacting the toner, to water is 80 - 100 deg.; and the molecular weight distribution obtained by the gel permeation chromatography of a THF-soluble component has >=peak below 2,000 and above 10,000 respectively, and the heat absorption peak by the binding agent component and the heat absorption peak by the releasing agent component do not overlap with each other in the differential scanning heating quantity measurement of components corresponding to the respective peaks. Consequently, the offsetting resistance and low-temperature fixing performance are both improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner for developing an electrostatic image and a fixing method for fixing a toner image to a recording material.

[Prior Art] Conventionally, a fixing device used in a thermal fixing method uses a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer that presses against the heating roller to remove unfixed toner. A roller fixing method is often used in which a transfer material on which an image is formed is heated while being nipped and conveyed.

In this type of device, unfixed toner on the transfer material
There is a problem called an offset phenomenon in which the toner adheres to the fixing roller side that is supposed to heat the toner and fuse it to the transfer material, and is transferred to the next transfer material. In particular, full-color devices use high-temperature fixing, in which multiple types of toner are mixed in a state close to melting, unlike the case of single-color fixing, which simply softens the toner and pressurizes it to stick. The trend is stronger.

As a means to prevent offset, it is common practice to include a crosslinking component in the toner; however, although this method imparts anti-offset properties, it conversely deteriorates the thermal melting properties of the toner.

That is, the presence of a crosslinking component is not preferable in color toners that require melting and mixing of multiple types of toners in order to reproduce intermediate colors. Therefore, in color heat roller fixing methods, high-temperature offset is prevented by applying a release material such as silicone oil to the roller side.

As a method to solve this problem, tl, s, P.

As disclosed in No. 3,578,797, a toner image is heated and melted by a heating element to its melting point, and the toner is cooled to a relatively high viscosity state to reduce the tendency of the toner to stick. A method is known in which fixing is performed without causing offset by peeling off from a heated web.

In addition to this, tl, s, P, No. 3,578,797 uses a method of heating the toner image and transfer material without pressurizing the toner image and the transfer material against the heating body, so there is no need to heat the transfer material. The company claims that it can fuse toner without any carbon and requires far less energy than other methods. However, when the toner is brought into contact with a heating body without pressure welding, as in Kochi, the heat transfer effect is reduced and it takes a relatively long time to heat and melt the toner. In particular, for full-color images, it is necessary to mix the toners of each color in a state close to melting, so this fixing method is not suitable for color systems. We are proposing to improve heat transfer efficiency by adding pressure/pressure welding technology to heat and melt toner in a short time and sufficiently. According to this method, since pressure and pressure are applied, it is possible to sufficiently heat and melt the toner, and there is no problem particularly with respect to color mixing in color images. However, since pressure is applied during heating and melting,
The adhesive force between the heating element and the toner becomes strong, and its releasability becomes a problem even after cooling.

Patent application 1986-14'78g 4 proposed by the present applicant
In this issue, a fixing device that heats a toner image via a moving heat-resistant sheet using a low-heat-capacity heating element that generates heat by energizing pulses and fixes it onto a recording material enables image formation with short wait time and low power consumption. A device has been proposed. Similarly, the patent application filed in 1983, which was previously proposed by the present applicant,
No. 12069 discloses that in a fixing device that heats and fixes a toner image onto a recording material via a heat-resistant sheet,
A fixing device has been proposed in which the heat-resistant sheet has a heat-resistant layer and a release layer or a low-resistance layer to effectively prevent the offset phenomenon.

However, in order to realize a fixing method that achieves excellent fixation of toner images on recording materials, prevents offset, etc., and has a short wait time and low power consumption, it is necessary to use in addition to the above-mentioned fixing device. This is largely due to the characteristics of the toner.

Generally, toner is manufactured by melt-mixing coloring agents such as dyes and pigments, additives such as charge control agents and mold release agents in a thermoplastic resin, and then uniformly dispersing the mixture. A method for producing toner having a desired particle size is known.

In order to achieve low-temperature fixing, it is necessary to use a thermoplastic resin with a low softening point in toner produced by these pulverization methods, but as a result, high-temperature offset phenomenon tends to occur, and it is difficult to add a release agent. Required. However, the addition of an excessive amount of release agent makes it impossible to perform sufficient melt mixing necessary for toner production, and even if the amount is adjusted, low-temperature fixability is maintained, high-temperature offset is prevented, and kneadability is improved. Furthermore, it has been practically difficult to provide toners with all the required transparency properties when used as color toners.

In contrast to these pulverized toners, polymerized toners have been proposed. [In the i0 publication, a hydrocarbon compound-containing polymerized toner is further disclosed in Japanese Unexamined Patent Publication No. 6
No. 1-46955 discloses polymerized color toners. Toners produced by these polymerization methods are generally obtained by suspension polymerizing a polymerizable monomer system in an aqueous medium, and because they do not undergo a pulverization process, large amounts of low softening point substances such as wax can be added. Furthermore, since a non-polar substance such as wax may exist on the particle surface and is encapsulated, it hardly affects the blocking property. The polymerized toner thus obtained has high-temperature offset resistance due to the addition of wax, but low-temperature fixability and low-temperature offset resistance are still insufficient.

[Problems to be Solved by the Invention] An object of the present invention is to provide a toner that solves the above-mentioned problems.

An object of the present invention is to provide a toner having excellent low-temperature fixability and low-temperature offset resistance and a wide non-offset area in the fixing method provided by the present invention.

An object of the present invention is to provide a toner having excellent color mixing properties, color reproducibility, and further excellent transparency in the fixing method provided by the present invention.

An object of the present invention is to provide a toner provided by the present invention,
The present invention provides a fixing method that is preferably used.

[i! [Means and effects for solving the problem] The problem of the present invention is to provide a toner that is obtained by suspension polymerizing a polymerizable monomer system containing at least a release agent and a colorant in an aqueous medium. and (2) the contact angle of the pellets obtained by molding the toner with water is 80 to 110 degrees, and [3
] The molecular weight distribution of the THF-soluble component by gel vermiacetic solar chromatography has one or more peaks below 2000 and one or more peaks above toooo, and ■ In differential scanning calorimetry of the components corresponding to each peak, heat absorption by the binder resin component was observed. A toner characterized in that the peak and the endothermic peak due to the release agent component do not overlap with each other is used; This problem can be solved by using a heat fixing device in which a pressure member brings the recording material into close contact with the heating body through a film.

The present invention will be explained in detail below.

As a result of intensive studies, the present inventors found that the release agent in the toner mainly contributes to preventing high-temperature offset, and that the glass transition temperature (Tg) of the crystalline resin is the dominant factor in low-temperature fixing of the toner. I found that it is. In order for the release agent to sufficiently function as a high-temperature offset prevention agent during fixing, it is preferable that the release agent is melted during fixing. However, heat absorption due to crystallization occurs in the release agent immediately before melting. is common, and as a result of the inventors' study,
It has been found that low-temperature fixing is inhibited when an endothermic peak due to crystallization is present. The inventors of the present invention conjecture the reason for this as follows. As mentioned earlier, for low temperature fixing, it is necessary to lower the Tg of the crystal resin.

On the other hand, if the Tg of the binder resin is lowered unnecessarily, toner blocking tends to occur, so the Tg of the binder resin is generally set at 50 to 70°C. In the case of the fixing device used in the present invention, the heating time during fixing is 0.03~
It is instantaneous at 0.1 seconds, and unlike a heat roller, the heat capacity of the fixing portion is small, so the amount of heat transferred to the toner is extremely small, especially when the fixing temperature is on the low side. In order to effectively use this small amount of heat for fixing, it is necessary not to add a substance having an endothermic peak near the Tg of the binder resin. However, since the addition of a mold-releasing substance is effective in preventing high-temperature offset, it is virtually impossible to exclude it. In order to solve these problems, the present inventors
As a result of extensive research, we have finally arrived at the present invention.

Generally, in differential scanning calorimetry of a releasing substance, two endothermic peaks are observed: one due to crystallization and the other due to melting. Of these, melting is an unavoidable endothermic process when using a crystalline substance, so the present inventors investigated a releasing substance to suppress the endothermic peak associated with crystallization, and improved low-temperature fixing properties. Ta.

In the present invention, the toner material is preferably selected so that the contact angle between the toner pellets and water is 80 to 110 degrees, and the material for the film surface of the fixing device is preferably a fluorine-containing substance.

The fluorine-containing substance on the surface of the fixing film has low surface energy and excellent mold releasability.

To make these film features more effective,
The material used for the toner is such that the contact angle of the toner pellets with water is 80 to 110 degrees. As a result, the attractive force between the toner and the film can be weakened during fixing, and offset resistance can be improved.

In order to control the contact angle of the toner pellets with respect to water, it is preferable to include a large amount of a substance having a contact angle of 80 to 110 degrees with respect to water. For example, polyethylene is 94
degree, polypropylene is 95 degrees, paraffin is 105 to 1
06 degrees etc.

The contact angle of toner pellets with water is 80 to 110.
Even at high temperatures, unless the surface is a film of fluorine-containing material, the characteristics of the toner will not necessarily be fully demonstrated. For example, a polyimide film coated with silicone oil for the purpose of imparting release properties can provide anti-offset properties, but even when combined with the toner of the present invention, results are better than those with a fluorine-based film on the surface. cannot be obtained. Moreover,
This is not necessarily a good combination because it consumes a lot of silicone oil, which increases running costs.

Examples of the mold release agent used in the present invention include the following.

(1) Use a mold release agent that does not have an endothermic peak associated with crystal transition.

It is known that a mold release agent with a long molecular chain does not have an endothermic peak associated with crystal transition. By selecting a release agent having an appropriate melting point among such release agents, both fixing properties and anti-offset properties can be achieved.

(2) A step of crystallizing the release agent is included in the toner manufacturing process.

During the toner production process, a step of heating near or above the melting point of the release agent is included, followed by a slow cooling step, and the contained release agent is crystallized during toner production, resulting in crystallization after tonerization. Hold down.

Specific examples of these mold release agents will be given below.

■High-melting paraffin wax: Paraffin is highly purified to extract only high-purity, high-molecular-weight components. The paraffin wax obtained in this way has a melting point of approximately 75°C.
As described above, due to the long chain length of the molecule, endotherm accompanying crystal transition does not occur.

■Grafted paraffin wax: Side chains are introduced into paraffin wax to inhibit rearrangement. For example, by introducing hydroxyl groups into paraffin wax by air oxidation and then modifying the hydroxyl groups, a wax that does not have an endothermic peak due to crystallization and has a relatively high melting point can be obtained.

The amount of these mold release agents added is 2 parts by weight per 100 parts by weight of monomer.
It is preferable to use it in a range of 40 parts by weight, preferably 4 to 20 parts by weight.

In the present invention, by using the above-described release agent, fixing properties are improved, and color mixing properties necessary for color copying and transparency of images on OHP sheets are also improved. In particular, with regard to the transparency of images on OHP sheets, as overhead projectors become smaller and lighter, the conventional transmissive type has become mainstream, and reflective types have become mainstream, and higher transparency has been required. In other words, in the transmission type, the light passes through the image only once, but in the reflection type, it passes twice, so the light transmittance that can be judged as good transparency in the transmission type is around 40%, whereas in the reflection type, the light transmittance is about 40%. According to the formula, a light transmittance of approximately 60% of the % power is required in the image. From this point of view, image transparency has become an important performance in color copying.

As the colorant used in the present invention, known colorants can be used, such as carbon black, iron black, C, 1,
Direct Red 1, C, 1, Direct Red 4, C
,1, Acid Red 1, C,1, Basic Red 1
, C,1, Modern Tread 30, c, r, Direct Blue 1, C,1, Direct Blue 2, C,1, Acid Blue 9, C,1, Acid Blue 15, c, r,
Basic Blue 3, C, 1, Basic Blue 5, C
, 1, Mordand Blue, C, 1, Direct Green 6, (, 1, Basic Green 4, C, i, Basic Green 6 dyes, yellow lead, cadmium yellow Mineral Fast Yellow Navel Yellow Naphthol Yellow S1 Banza Yellow 01 Permanent Yellow NCG.

Tartrazine Lake, Molybdenum Orange, Permanent Orange GTR, Benzidine Orange G1 Cadmium Red, Permanent Red 4R1 Watching Red Calcium Salt, Brilliant Cardine 3B, Fast Violet B1 Methyl Violet Lake, Deep Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Pigments include Blue Lake, Quinacridone, Rhodamine B1 Phthalocyanine Blue, Fast Sky Blue Pigment Green B1 Malachite Green Lake, and Final Yellow Green G.

In the present invention, since the toner is obtained using a polymerization method, it is necessary to pay attention to the polymerization inhibiting property of the colorant and the water phase octagonism, and it is preferable to use a surface-modified substance, for example, a substance that does not inhibit polymerization. It is better to perform hydrophobization treatment using especially,
Many dyes and carbon blacks have polymerization inhibiting properties, so care must be taken when using them. A preferred method for surface treating the dye system is a method in which polymerizable monomers are prepolymerized in the presence of these dyes, and the resulting colored polymer is added to the monomer system. In addition, for carbon black, in addition to the same treatment as the dye above,
Grafting treatment may be performed with a substance that reacts with the surface functional groups of carbon black, such as polyorganosiloxane.

These colorants are 0.5 to 2 parts by weight of the monomer.
0 parts by weight are used, preferably 1 to 10 parts by weight are used.

Examples of polymerizable monomers that can be used in the above polymerized toner include styrene, 0-methylstyrene, m-methylstyrene, and p-methylstyrene.
- Styrenic monomers such as methylstyrene, p-methoxystyrene, p-ethylstyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate・Acrylic acid esters such as dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate・Methacrylic acid esters such as isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, M2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. Other acrylonitrile and methacrylonitrile - Monomers such as acrylamide may be mentioned.

These monomers may be used alone or in combination. Among the above-mentioned monomers, it is preferable to use styrene or styrene derivatives alone or in combination with other monomers from the viewpoint of toner developability and durability.

The molecular weight distribution of the THF-soluble portion of the toner by GPC must have one or more peaks at 2,000 or less and at 10,000 or more, respectively. This is due to the fact that the THF-soluble components with a molecular weight of io, ooo or higher mainly have offset resistance,
It is effective for sticking resistance, and has a THF-soluble component with a molecular weight of 2,
This is based on the fact that components of 000 or less are effective in releasability from the fixing roller.

In the present invention, it is desirable to add a charge control agent to the toner material for the purpose of controlling the chargeability of the toner. As these charge control agents, among the known ones, those having almost no polymerization inhibiting property or water phase migration property are used. For example, positive charge control agents include nigrosine dyes, triphenylmethane dyes, quaternary ammonium salts, and amines. Examples of the negative charge control agent include metal-containing salicylic acid compounds, metal-containing monoazo dye compounds, styrene-acrylic acid copolymers, and styrene-methacrylic acid copolymers.

These charge control agents are 0.1 parts by weight per 100 parts by weight of the monomer.
~30 parts by weight are used, preferably 1 to 15 parts by weight are used.

The dispersion medium used in the present invention may include any suitable stabilizer, such as polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and its salts, starch, tricalcium phosphate, etc. -Aluminum hydroxide, magnesium hydroxide, calcium metasilicate, barium sulfate, bentonite, etc. can be used by dispersing them in the water phase. This stabilizer is
It is preferable to use 0.2 to 20 parts by weight based on 100 parts of the polymerizable monomer.

In addition, due to the fine dispersion of these stabilizers, the
0.1 parts by weight of surfactant may be used. This is to promote the intended action of the above-mentioned dispersion stabilizers, and specific examples include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, and lauric acid. Sodium/potassium stearate/
Examples include calcium oleate.

It is more preferable to add and polymerize a polymer/copolymer having a polar group as an additive to the monomer system. Furthermore,
In the present invention, a monomer system containing a polar group-containing polymer/copolymer or cyclized rubber is suspended in an aqueous phase in which a dispersant having an opposite charge to the polar polymer is dispersed, and polymerization is carried out. It is preferable to do so. That is, the cationic or anionic polymer/copolymer or cyclized rubber contained in the monomer system is polymerized with the oppositely charged anionic or cationic dispersant dispersed in the aqueous phase. The particles are electrostatically attracted to each other on the surface of the particles that become the toner, and the dispersant covers the particle surface to prevent the particles from coalescing and stabilize them, and the polar polymer added during polymerization gathers on the surface of the particles that become the toner. Therefore, it takes on a kind of shell-like shape, and the resulting particles become pseudo-capsules. A relatively high molecular weight polar polymer/copolymer or cyclized rubber is used to give toner particles excellent blocking properties and developer abrasion resistance, while a relatively low molecular weight internal material improves fixing properties. By carrying out polymerization in such a way that it contributes to the fixing properties, it is possible to obtain a toner that satisfies the contradictory requirements of fixing properties and blocking properties. Examples of polar polymers/copolymers and counterloading dispersants that can be used in the present invention are shown below.

(1) Examples of the cationic polymer include polymers of nitrogen-containing monomers such as dimethylamine ethyl methacrylate and diethylaminoethyl methacrylate, or copolymers with styrene and unsaturated carboxylic acid esters.

(2) Examples of anionic polymers include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid and methacrylic acid,
Other examples include saturated dibasic acids, unsaturated dibasic acid anhydrides, polymers of nitro monomers, and copolymers with styrene monomers. Furthermore, cyclized rubber may be used instead of these polar polymers.

(3) As the anionic dispersant, silica fine powder is preferably used, especially with a BET specific surface area of 20 Or//g
The above colloidal silicas are suitable.

(4) As the cationic dispersant, aminoalkyl-modified colloidal silica (preferably has a BET specific surface area of 20
Hydrophilic positively chargeable silica fine powder such as 0rrr/g or more),
Examples include aluminum hydroxide.

It is preferable to use such a dispersant in an amount of 0.2 to 20 parts by weight based on 100 parts by weight of the polymerizable monomer. More preferably, it is 0.3 to 15 parts by weight.

As the polymerization initiator, any suitable polymerization initiator such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile,
1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,
Azo or diazo polymerization initiators such as 4-dimethylvaleronitrile, azobisisobutyronitrile, etc.; Examples include oxide polymerization initiators. Generally, it is sufficient for these polymerization initiators to be added in an amount of 0.5 to 10% by weight of the polymerizable monomer.

The polymerized toner used in the present invention can be obtained by the following method. That is, a monomer system in which release agents, colorants, charge control agents, polymerization initiators, and other additives are added to polymerizable monomers and uniformly dissolved or dispersed using a homogenizer, ultrasonic disperser, etc. It is dispersed in an aqueous phase containing a dispersion stabilizer using a conventional stirrer, homomixer, homogenizer, etc. Preferably, the stirring speed and time are adjusted so that the monomer droplets have the desired toner particle size, generally 30 μm or less, and after that, the particle state is maintained by the action of a dispersion stabilizer, and the particle size is It is sufficient to perform stirring to an extent that sedimentation is prevented.

The polymerization temperature is set at 40°C or higher, generally from 50 to 90°C. After the reaction is completed, the generated toner particles are collected by washing and filtration, and then dried. In the suspension polymerization method, 30 parts by weight of water is usually added to 100 parts by weight of the monomer system.
Preferably, 0 to 3000 parts by weight are used as dispersion medium.

It is preferable that the toner according to the present invention has a substantially spherical shape and has minute irregularities on the surface. Methods for obtaining such a toner include fusing fine particles to the surface of spherical particles by any method, or making the surface uneven at the stage of producing the spherical particles. Examples of methods for obtaining the toner having an uneven surface according to the present invention include the following methods.

l) Mechanochemical method After mixing the bispherical toner particles and fine resin particles, the fine resin particles are fused to the surface of the toner particles by a mechanochemical method.

2) Dry heat treatment method: After mixing spherical toner particles and fine resin particles, the mixture is heated in a fluidized heating bed to fuse the fine resin particles to the surface of the toner particles.

3) Wet heat treatment method: After mixing spherical toner particles and fine resin particles in a liquid or gas, heat treatment is performed in the liquid to fuse the fine resin particles to the surface of the toner particles.

4) Method of adding fine resin particles during toner particle polymerization: When obtaining toner particles by polymerization, it is necessary to add fine particles to the monomer (or add fine resin particles during the polymerization process). By controlling the physical properties of the resin particles and dispersion system, the resin particles are transferred to the toner surface.
Complete polymerization.

5) Drying method after swelling: Toner particles are once immersed in a solvent and swelled, and then dried in a heated air stream or under reduced pressure.

At this time, spheroidization processing may also be performed.

The fine resin particles used for providing unevenness in the present invention have a particle size in the range of 1/200 to 1/1O1, preferably 1/100 to 1/10, of the spherical toner particles, and the material thereof is, for example, styrene-based. Resins, styrene-acrylic ester copolymers, styrene-methacrylic ester copolymers, copolymers of styrene and other vinyl monomers (e.g. acrylonitrile, butadiene, etc.), polyester resins, epoxy resins. An appropriate one is used.

Among these resins, vinyl resins are particularly preferably used because resin fine particles can be easily obtained by emulsion polymerization or the like.

The additives used in the present invention for imparting various properties preferably have a particle size of 1/10 or less of the volume average diameter of the toner particles from the viewpoint of durability when added to the toner. The particle size of the additive means the average particle size determined by observing the surface of toner particles using an electron microscope. Examples of additives aimed at imparting these properties include:
The following are used:

1) Fluidity imparting agent: metal oxides (silicon oxide, aluminum oxide, titanium oxide, etc.), carbon black, carbon fluoride, etc. Each of them is more preferably subjected to hydrophobization treatment.

2) Abrasives: Metal oxides (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitrides (silicon nitride, etc.), carbides (
silicon carbide, etc.) metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), etc.

3) Lubricant: Fluorine resin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), etc.

4) Charge controllable particles: metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.), carbon black, etc.

These additives are added in an amount of 0.00 parts by weight per 100 parts by weight of toner particles.
1 to 10 parts by weight are used, preferably 0.1 to 5 parts by weight. Even if these additives are used alone,
Also, a plurality of them may be used together.

Particle size distribution measurement in the present invention will be described.

A Coulter counter TAU model (manufactured by Coulter) was used as the measuring device, and an interface (manufactured by Nikkaki) that outputs the number average distribution and volume average distribution was connected to the CX-1 personal computer (manufactured by Canon). Prepare a 1% NaCl2 aqueous solution using grade sodium chloride.

As a measuring method, 0.1 to 5 rr+42 of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 mβ of the electrolytic aqueous solution, and 0.5 to 50 mg of the measurement sample is added.

The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the particle size distribution of particles of 2 to 40 μm was measured using a 100 μm aperture as an aperture using the Coulter Counter TA-II model. to find the volume average distribution and number average distribution.

From these determined volume average distribution and number average distribution, the volume average particle diameter can be obtained.

Differential scanning calorimetry (DSC) in the present invention is DSC
-7 (manufactured by PerkinElmer) at a heating rate of 10℃/
Do it in min. Further, in the DSC curve of the wax component, the temperature at the top of the peak showing the maximum endotherm is defined as the melting point of the wax.

The measurement of contact angle in the present invention will be described.

The toner is made into pellets using a tablet press.

At this time, use a molding machine with a mirror finish and apply sufficient pressure to obtain a smooth surface. The contact angle of the obtained pellet with water at 23° C. was measured using a contact angle meter (Kyowa Scientific CA-DS model).

The molecular weight distribution of the toner of the present invention was measured as follows.

1 Sample Preparation (i) Standard Sample The commercially available standard polystyrene shown below is used as the standard sample.

Molecular weight Manufacturer 8.42X10' Toyo Tsudani Gyo ■ (hereinafter abbreviated as T) 2,7 X 10' Waters As5
ociates (hereinafter abbreviated as W) 1.2 Xl06 W 7, 75X10' T 4.7 XIO' W 2, OXIO' W 3.5 XIO' W l, 5 XIO' W l, 02X10' T 3.6 XIO "W 2.35X10" W 5, OXIO" T About 3 mg of the above standard polystyrene is dissolved in 30 ml of tetrahydrofuran (THF) to prepare a standard sample.

(ii) Unknown sample 60 mg of unknown sample (toner) is extracted with 75 mg of THF, centrifuged and filtered to obtain an unknown sample.

2 Measurement Conditions Measurement was carried out under the following conditions using WATERS 150CALC/GPC as an apparatus.

Solvent: THF (Kishida Chemical special grade) Column: Shodex KF-801,802゜803.804,80
5,806°807 (manufactured by Showa Denko) Temperature = 40°C Flow rate: 1. Omi! ,/min Injection amount: O, 1 mρ Detector: RI 3 Data processing Under the above measurement conditions, read the retention time at the peak of the standard sample to create a calibration curve, and calculate the molecular weight of the unknown sample from the calibration curve.

The substantial gel content in the toner according to the present invention was determined as follows.

Contents: 100mI2. 1 g of toner was placed in a centrifuge tube, 50 mg of toluene was added, and the mixture was heated to 50° C. and immersed in an ultrasonic bath to extract the resin component for 20 minutes. The centrifuge tube was placed in a centrifuge, and separation was performed at 10,000 rpm for 30 minutes to remove the supernatant. Further, 50 mβ of toluene was added and the same operation was performed to remove the upper layer. After repeating this operation three more times, the insoluble components were taken out and dried. When the amount of insoluble components obtained was 8% or less of the initial amount of toner, it was determined that there was no substantial gel content in the toner.

On the other hand, in the present invention, the heating body has a smaller heat capacity than a conventional heating roll (it has a linear heating section, and the maximum temperature of the heating section is preferably 100 to 300°C).

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

The structure of the film in the present invention is that these heat-resistant sheets have a release layer and/or a low resistance layer.

The surface characteristics of the surface of the film of the present invention that comes into pressure contact with the recording material are that it has a critical surface tension of 30 dyn/cm or less and a surface electrical resistance of 1010 Ω/crrr or less.

The film to be applied to the present invention is made of a heat-resistant material such as polyimide, polyetherimide, PES, or PFA as the heating body pressure contact surface, and at least the surface image contacting surface is made of PTFE,
A conductive material is added and dispersed in a binder resin with a critical surface tension of 30 d3'n/cm or less, and the surface electrical resistance is 101
A multilayer coated film having a low resistance release layer having a value of 0 Ω/cm or less is more preferably used. Conductive materials for controlling surface electrical resistance that are preferably used in the present invention include carbon black, graphite, and inorganic oxides.

When the critical surface tension of the surface of the film used in the heat fixing method of the present invention that comes into pressure contact with the recording material exceeds 30 dyn/cm, the so-called offset phenomenon in which toner adheres to the film surface becomes noticeable.

In addition, when the surface electrical resistance exceeds 10I0Ω/cm,
The so-called electrostatic offset phenomenon, in which toner electrostatically adheres to the film surface, becomes noticeable.

The method for measuring surface electrical resistance in the present invention conforms to JIS standard 6911.

In the present invention, the critical surface of the surface that comes into pressure contact with the recording material is determined by measuring the contact angle θ exhibited by various organic liquids (hydrocarbons and others) with different surface tensions γ on the film surface, and Z i sma
It was determined by performing n plot.

Hereinafter, preferred embodiments of the present invention will be described based on the accompanying drawings, but this is not intended to limit the present invention in any way.

FIG. 5(a) shows a structural diagram of the fixing device of this embodiment.

Reference numeral 11 denotes a low heat capacity linear heating element fixedly supported on the device, and as an example, a resistive material 13 is coated on an alumina substrate 12 having a thickness of 1.0 mm + width of 10 mm and a length of 240 mm to a width of 1.0 mm. energized from both ends in the longitudinal direction. The current is applied in a pulse-like waveform of DClooV with a period of 20 m5 ec, and pulses are given by varying the pulse width in accordance with the desired temperature and energy release amount controlled by the temperature measuring element 14. Approximate pulse width is 0.5m5ec~5m
It becomes 5eC. The fixing film 15 is brought into contact with the heating body 11 whose energy and temperature are controlled in this way, and the fixing film 15 is moved in the direction of the arrow in the figure.
moves. As an example of this fixing film, the thickness is 20 μm.
It is an endless film coated with a release layer of 10 μm in which carbon black is added as a conductive material to polyimide, imide on the side in contact with the heating element, PTFE on the side in contact with the image, and carbon black as a conductive material.

The critical surface tension of the surface of this film that comes into pressure contact with the recording material is
20 dyn/crtr, and the surface electrical resistance is 106
Ω/cITIl+.

Generally, the total thickness is less than 100 μm, preferably less than 40 μm. The film is driven by the drive roller 16 and the driven roller 17 and is tensioned to move the film 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 with 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 is heated as described above to obtain a fixed image.

The above explanation was made using an endless belt, but as shown in FIG. 5(b),
The fixing film may be an edged film.

Further, as image forming apparatuses, the present invention is applicable to all types of fixing apparatuses that form images using toner, such as copying machines, printers, and facsimiles.

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 about 10 to 30 degrees Celsius lower than T1. Further, the film surface temperature T3 at a portion where the film 15 is peeled off from the toner fixed surface is approximately equal to the temperature T2.

[Examples] Hereinafter, the present invention will be described in detail based on Examples. Note that all parts are parts by weight.

Add 0.25 g of γ-aminopropyltrimethoxysilane to 1200 mI2 of ion-exchanged water, then add 5 g of hydrophilic colloidal silica (BET specific surface area 200 d/g), heat to 80°C, and use a TK homomixer. 10. Using M type (manufactured by Tokushu Kika Kogyo). Dispersion was performed for 15 minutes at OOOrpm.

Furthermore, 1/10N-HCn aqueous solution was added to adjust the system pH to 6.
And so.

The above formulation was heated to 80° C. in a container, and dissolved and dispersed using a TK homomixer to obtain a monomer mixture. Further, while maintaining the temperature at 80°C, 10 parts of dimethyl 2,2'-azobisisobutyrate as an initiator was added and dissolved to prepare a monomer composition. The above monomer composition was put into a 2β flask containing the dispersion medium obtained above, and the mixture was heated for 80 minutes under a nitrogen atmosphere.
12. Using a TK homomixer at ℃. The monomer composition was granulated by stirring at OOO rpm for 60 minutes. Thereafter, polymerization was carried out at 80° C. for 20 hours while stirring with a paddle stirring blade.

After the polymerization reaction was completed, the reaction product was cooled, an aqueous NaOH solution was added to dissolve the dispersant, and spherical particles were obtained by filtration, washing with water, and drying.

When the particle size of the obtained spherical particles was measured using a Coulter counter (aperture size 101004z), the volume average diameter was 6.8 μm and a sharp particle size distribution was found.

Separately, put 150 parts of ion-exchanged water into a reaction container, and add 80 parts of ion-exchanged water.
℃, and with further stirring, 1 part of a monomer system of styrene/n-butyl methacrylate = 90/10 (7 parts) and 1 part
10 parts of a 0% by weight ammonium persulfate aqueous solution was added, and 99 parts of the above monomer system were added dropwise over 3 hours to obtain a seed latex, then 10 parts of methacrylic acid was added dropwise, and 3
Polymerization was continued for hours. After the polymerization is completed, it is cooled, washed with water, filtered, and dried until the volume average diameter is 0 by Coulter N4.
．． Spherical fine resin particles of 6 μm were obtained.

Add 5 parts of the above resin fine particles to 50 parts of the previously obtained spherical particles,
The mixture was dispersed and mixed using a Henschel mixer. Separately, add 0.25 g of γ-aminopropyltrimethoxysilane to 1200 mρ of ion-exchanged water, add wood-loving colloidal silica (BET specific surface area 200 rrl'/g), and add TK type homomixer M type (manufactured by Tokushu Kika Kogyo Co., Ltd.). ) for 15 minutes at OOOrpm, then 1/1ON-
An aqueous HCβ solution was added to adjust the system pH to 6.

Place this in an autoclave, add the mixed particles from above,
Immobilization treatment was performed for 30 minutes under heating and stirring at 110° C./l and 2 kg/crrr. After the treatment, the dispersion system was cooled, and the dispersant was removed using an alkali, followed by washing with water, filtration, and drying to obtain textured spherical particles.

The volume average diameter of the obtained particles was 7.9 μm according to a Coulter counter (aperture diameter 10100 μm).

As a result of the toluene dissolution method and the measurement of the insoluble content of the uneven spherical particles, it was found that the pigment content in the insoluble content was 98% by weight, and there was no substantial gel content. Furthermore, as a result of molecular weight distribution measurement by GPC of the THF-soluble portion of the spherical particles, the molecular weight was 2.0XIO' and 1°2X10
The resulting GPC chart is shown in Figure 3. Using GPC, each component was fractionated at an elution time corresponding to the half-width of each peak. When the peaks were confirmed, it was confirmed that the endothermic peak (62.2°C) of the resin component and the endothermic peak (79.6°C) due to the mold release agent component did not overlap, as shown in FIG.

The contact angle of the pellets formed from this toner with water is 1
It was 00 degrees.

To 100 parts of the unevenness-imparting spherical particles, 0.6 part of fine silica powder having a specific surface area of 200 rrl'/g by the BET method and hydrophobized with hexamethyldisilazane was externally added to prepare a toner. For 10 parts of this toner, styrene-
90 parts of acrylic resin-coated ferrite carrier was mixed to prepare a developer.

Using this developer and externally added toner, an unfixed image was obtained using a full color copying machine CLC-500 manufactured by Canon.

A fixing test was conducted on this unfixed image using a heat fixing device shown in FIG. 5(a).

In the heat fixing device shown in FIG. 5(a), the power consumption of the resistance material 13 in the heating section is 150 W, the total pressure between the heating body 11 and the pressure roller 18 is 5 kg, and the nip between the pressure roller 18 and the film 15 is 3mm, fixing speed 25mm/sec
It was set to

The fixing film 15 has a thickness of 2 and has a low-resistance release layer made of PTFH with a conductive substance (carbon black) dispersed thereon on the contact surface with the toner carrier 19 having the toner 20.
A 0 μm polyimide film was used. During the fixing test, the temperature was controlled by the temperature measuring element 14 of the heating body 11, and the fixing test was conducted at every 10°C from 90 to 200°C.

As an evaluation method, the obtained fixed image was rated at 50g/crrr.
The fixing start temperature was set as the temperature at which the image density reduction rate before and after rubbing was 5% or less.

Further, offset evaluation was performed by observing images. Furthermore, the transparency of the HP sheet was evaluated by fixing it at 140 DEG C. and measuring its light transmission spectrum using a spectrophotometer U-3400 (manufactured by Hitachi). The amount of toner on the unfixed image was 0.55±0.05 mg/cnf. the result,
The fixing start temperature is as low as 110°C, and the non-offset area is 1
The temperature was 10°C to 160°C, and low-temperature fixing was achieved. The chroma of the fixed image was 73.2, and the transparency of the image on the OHP sheet using a transmissive overhead projector when fixed at 140°C was good, and the spectral transmittance at 560 parts m was 50%. Ta. The results are shown in Table-1.

After a running test of 30,000 sheets, the image density was 1.4 or higher, there was no fog, the resolution and gradation were both excellent, and there was no toner cleaning failure, and the toner inside the copying machine There was no noticeable scattering. Further, when the toner before and after durability was observed under an electron microscope, no deterioration of the externally added silica particles was observed.

Add 480 parts of 0.1 M sodium triphosphate aqueous solution to 650 mff of ion-exchanged water, heat to 80°C, and stir at high speed.
72 parts of IM calcium chloride aqueous solution was added dropwise.

The above formulation was heated to 80° C. in a container, and dissolved and dispersed using a TK homomixer to obtain a monomer mixture. Further, while maintaining the temperature at 80"C, 810 parts of dimethyl 2,2'-azobisisobutycean initiator was added and dissolved to prepare a monomer composition. The above monomer composition was placed in a flask and heated at 80°C under a nitrogen atmosphere at 9000 rpm using a TK homomixer.
The mixture was stirred for 60 minutes to granulate the monomer composition. after that,
Polymerization was carried out at 80° C. for 20 hours while stirring with a paddle stirring blade. After the polymerization reaction was completed, the reaction product was cooled, an aqueous HCJ2 solution was added to dissolve the dispersant, and spherical particles were obtained by filtration, washing with water, and drying.

The volume average diameter of the obtained particles was 8.4 μm as measured by a Coulter counter (aperture diameter: 100 μm).

As a result of measuring the toluene insoluble content of the spherical particles in the same manner as in Example 1, it was found that the pigment content in the insoluble content was 99.5% by weight and there was no substantial gel content. Furthermore, as a result of measuring the molecular weight distribution in the same manner as in Example 1, the result was 1.9X1
It had peaks at 0' and 1.3 It was confirmed that the endothermic peaks (76.2°C) of the mold agent components did not overlap.

Further, the contact angle of the pellets formed from this toner with water was 95 degrees.

To 100 parts of the spherical particles, 0.6 parts of fine silica powder having a specific surface area of 200 rrr/g by the BET method and hydrophobized with hexamethyldisilazane was externally added to prepare a toner. 90 parts of styrene-acrylic resin-coated ferrite carrier was mixed with 10 parts of this toner to prepare a developer.

Using the developer thus obtained, Canon C.
An unfixed image was obtained using LC-500, and Example 1
A fixation test was conducted in the same manner.

When the same evaluation as in Example 1 was performed, the fixing start temperature was as low as 110°C (the non-offset area was 110 to 160°C).
As a result, low-temperature fixing was achieved. The saturation of the fixed image is 4
4.0, and the transparency of the image on an OHP sheet using a transmission type overhead projector during fixing at 140 DEG C. was particularly good, with a spectral transmittance of 48% at 460 parts.

The results are shown in Table-1.

Mitatejoyu A dispersion medium was prepared in the same manner as in Example 2.

Granulation was carried out using the same formulation as in Example 2. Further, polymerization was carried out at 80° C. for 20 hours while stirring with a paddle stirring blade. Further, transfer to an autoclave and heat at 150°C for 30 minutes.
After heating and stirring to ℃/2 kg/c, 10℃
/min to room temperature. Furthermore, H.C.
A ρ aqueous solution was added to dissolve the dispersant, followed by filtration, washing with water, and drying to obtain spherical particles.

The volume average diameter of the obtained particles measured by Coulter counter (aperture diameter 100 μm) was 8. It was 0 μm. As a result of measuring the toluene insoluble content of the spherical particles in the same manner as in Example 1, it was found that the pigment content in the insoluble content was 99.9% by weight and there was no substantial gel content. Furthermore, as a result of measuring the molecular weight distribution in the same manner as in Example 1, 2. lX
l0' and 1. It had a peak at 1X10''.
After separating each component in the same manner as in Example 1, DSC measurements revealed that the endothermic peak of the resin component (56.7"C) and the endothermic peak of the release agent component (74.9"C) overlapped. I was able to confirm that there was no such thing.

The contact angle of the pellets formed from this toner with water is 1
It was 02 degrees.

To 100 parts of the unevenness-imparting spherical particles, 0.6 part of fine silica powder having a specific surface area of 200 rrr/g by the BET method and hydrophobized with hexamethyldisilazane was externally added to prepare a toner. 90 parts of styrene-acrylic resin coated ferrite carrier are mixed with 10 parts of this toner,
It was used as a developer.

Using this developer and externally added toner, an unfixed image was obtained using a full color copying machine CLC-500 manufactured by Canon. A fixing test was conducted using the same fixing tester as in Example 1.

When the same evaluation as in Example 1 was performed, the fixing start temperature was as low as 110°C, and the non-offset area was 110 to 160°C.
As a result, low temperature fixing was achieved. The saturation of the fixed image is 62
．． 5, and the transparency of the image on the OHP sheet using a transmissive overhead projector during fixing at 140 DEG C. was good, with a spectral transmittance of 46% at 660 parts.

The results are shown in Table-1.

11A Using the developer obtained in Examples 1 to 3, CLC manufactured by Canon Co., Ltd.
-500, a three-color full-color unfixed image was obtained, and the same fixing test as in Example 1 was conducted.

In particular, as a full-color image, the saturation of the mixed color portion and the transparency of the OHP sheet were evaluated. As a result, the fixing start temperature was 110 for each red, green, and blue image area.
℃, the non-offset area was 110 to 160°C, and low-temperature fixing was achieved even in full color images. In addition, the saturation of the red, green, and blue image areas at 150°C was 51.2, 43.5, and 46.8, respectively. The transparency of the image on the OHP sheet is particularly good, and the spectral transmittance of each wavelength in the red part (660 parts), green part ('560 nm), and blue part (460 nm) is 41% (660 parts). m), 4
4% (560 parts m) and 42% (460 parts m).

The results are shown in Table-1.

L comparison ±] In the same manner as in Example 1 except that the formulation in Example 1 was changed as follows (aperture diameter: 1001.Lm), unevenness-imparting spherical particles with a volume average diameter of 8.1 μm as measured by a Coulter counter (aperture diameter: 1001.Lm) were obtained. Ta.

(Formulation) As a result of measuring the insoluble content of the textured spherical particles by a toluene dissolution method, it was found that the pigment content in the insoluble content was 98% by weight, and there was no substantial gel content. Furthermore, as a result of measuring the molecular weight distribution in the same manner as in Example 1, it was found that 2.0XI
It had peaks at O' and 1.0x103. The obtained GPC chart is shown in FIG. In addition, after each component was separated in the same manner as in Example 1, DSC was measured, and the endothermic peak of the resin component (62.0°C) and the endothermic peak of the mold release agent component (main peak value 70.0°C, It was confirmed that the other endothermic peaks associated with crystallization overlapped.

The contact angle of the pellets formed from this toner with water is 1
It was 0.6 degrees.

A developer was prepared using the uneven spherical particles in the same manner as in Example 1, and the fixability was evaluated.

As a result, the fixing start temperature was 120°C, and the non-offset area was 120 to 140°C. The saturation of the fixed image is 6
0.2, there is virtually no problem with the transparency of the image on the OHP sheet when fixed at 140°C using a transmission type overhead projector, but the transparency is slightly lacking and the image has a blackish tinge. The spectral transmittance was 36%. Also, 30
．． The results of the 000-sheet running test were as good as in Example 1.

Stable Comparison A cyan developer was obtained in the same manner as in Example 2, except that the grafted paraffin wax in Example 2 was replaced with paraffin wax having a melting point of 70°C.

Further, in the toner formulation in Example 3, a magenta developer was obtained in the same manner as in Example 2 except that paraffin wax with a melting point of 70° C. was used instead of high melting point paraffin wax (melting point 75° C.). After forming these toners into pellets, the contact angle with water was measured, and the contact angle with water was 103 degrees for the cyan toner and 100 degrees for the magenta toner.

Using the yellow developer obtained in Comparative Example 1 and the cyan and magenta developers described above, a three-color full-color image was evaluated in the same manner as in Example 4. As a result, the fixing start temperature was 120°C in each of the red, green, and blue image areas, and was 120 to 140°C in the non-offset area. Furthermore, the saturation of the red, green, and blue image areas at 140°C was 43.2, 36.5, and 40.3, respectively, indicating poor color reproducibility, and when fixed at 140°C using a reflective overhead projector. Although the image on the OHP sheet can be recognized in color, it lacks transparency and has a blackish tinge, and the spectral transmittance of each wavelength for the red part (660 nm), green part (560 nm), and blue part (460 nm) is as follows.
33% (660nm), 30% (560nm), 34%
(460 nm).

The results are shown in Table-1.

After thoroughly premixing with a Henschel mixer,
The mixture was melt-kneaded twice or more in a three-roll mill, and after cooling, it was coarsely pulverized using a hammer mill to a particle size of about 1 to 2 mm.Then, it was finely pulverized using an air jet type pulverizer. Classify the crushed material to obtain a volume average diameter of 1
A toner of 2.0 μm was obtained. The contact angle of the pellets formed from this toner with water was 69 degrees.

This toner was added externally to form a developer in the same manner as in Example 1, and then a fixing test was conducted.

As a result, although fixation was achieved at 150° C., there was no non-offset region, and the offset shifted from low temperature to high temperature, making it unsuitable for practical use.

(The following is a blank space) [Effects of the Invention] According to the present invention, the material of the toner used in a specific heat fixing device is studied, and the endothermic peak of the release agent component and the water resistance of the pellets obtained by molding the toner are determined. By regulating the contact angle, it is possible to provide a toner that is particularly excellent in both anti-offset properties and low-temperature fixing properties.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the endothermic peak measured by DSC of Example 1, and FIG. 2 is a diagram showing the endothermic peak measured by DSC of Comparative Example 1. FIG. 3 is a diagram showing a GPC chart of Example 1, and FIG. 4 is a diagram showing a GPC chart of Comparative Example 1. FIG. 5(a) shows a schematic sectional view of a fixing device for implementing the fixing method of the present invention, and FIG. 5(b) shows a schematic cross-sectional view of a fixing device for implementing the fixing method of another aspect of the present invention. A schematic cross-sectional view of a fixing device is shown. 11... Heating body 12... Alumina substrate 1
3... Resistance material 14... Temperature measuring element 15...
・Fixing film 16... Drive roller 7... Followed roller 18... Pressure roller 9... Recording material 0... Unfixed toner image 1 supported on recording material...
・Log guide with fixing device 4... Sheet feed shaft 7... Winding shaft

Claims (2)

[Claims] (1) Used in a heat fixing device consisting of a fixedly supported heating body and a pressure member pressed against the heating body, the pressure member bringing the recording material into close contact with the heating body through a film. [1] A toner obtained by suspension polymerizing a polymerizable monomer system containing at least a release agent and a colorant in an aqueous medium; [2] Molding the toner. The contact angle of the pellets obtained with water is 80 to 110 degrees, and [3] The molecular weight distribution of THF-soluble components measured by gel permeation chromatography is 2000 or less and 10000.
Each of the above has one or more peaks, and [4] In differential scanning calorimetry of the components corresponding to each peak, the endothermic peak due to the binder resin component and the endothermic peak due to the release agent component do not overlap with each other. Toner for developing electrostatic images. (2) A method of heat-fixing a toner image on a recording material using a heat-fixing device, in which: A) the toner forming the toner image contains a polymerizable monomer system containing at least a release agent and a colorant; It is a toner obtained by suspension polymerization in an aqueous medium, [2] the contact angle of pellets obtained by molding the toner with water is 80 to 110 degrees, and [3] gel permeable with THF soluble content. Molecular weight distribution by cation chromatography is below 2000 and 10000
Each of the above has one or more peaks, and [4] In differential scanning calorimetry of the components corresponding to each peak, the endothermic peak due to the binder resin component and the endothermic peak due to the release agent component do not overlap with each other. B) a fixedly supported heating body as the heat fixing device;
A fixing method characterized by using a heat fixing device comprising a pressure member that is in pressure contact with the heating member in opposition to the heating member, and the pressure member brings the recording material into close contact with the heating member via a film.