JPH05119530A - Heat fixing toner and heat fixing method - Google Patents

Abstract

PURPOSE:To obtain a fixed image having excellent fine line reproducibility and gradation characteristic. CONSTITUTION:Toner particles having 4 to 8mum weight average grain sizes and <=5mum grain size are incorporated at 17 to 60number%, the toner particles having 6.35 to 10.08mum grain sizes are incorporated as 5 to 50number% and the toner particles having >=12.7mum grain size are incorporated at <=2.0vol.%. into the heat fixing toner 20 to be used for a fixing method for heat fixing a toner image by a heating body fixing and supported to a recording material and a pressurizing member which is in opposite pressurized contact with the heating body and brings the recording material into tight contact with a body to be heated via a film. The toner particle groups having <=5mm have a grain size districution satisfying N/V=-0.05N+K.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic printing,
The present invention relates to a heat fixing method for heating and fixing a visible image formed of a toner on a recording material in magnetic recording and the like, and a heat fixing toner used in the fixing method.

[0002]

2. Description of the Related Art In recent years, the use of image forming apparatuses such as electrophotographic copying machines has been widespread, and the demand for image quality thereof has become strict. When copying an image such as a general document or book, it is required to reproduce extremely fine and faithful reproduction of even minute characters without being crushed or broken. In particular, when the latent image on the photoconductor of the image forming apparatus is a line image of 100 μm or less, the fine line reproducibility is generally poor with the conventional developer, and the sharpness of the line image is still insufficient.

In particular, in an image forming apparatus such as an electrophotographic printer that uses a digital image signal, a latent image is formed by collecting dots of a fixed unit, and a solid portion, a halftone portion and a light portion are dots. It is expressed by changing the density. However, when the toner particles do not faithfully adhere to the dots and the toner particles protrude from the dots, it is impossible to obtain the gradation of the toner image corresponding to the ratio of the dot density of the black portion and the white portion of the digital latent image. There is a problem. Further, in order to improve the image quality, when the dot size is reduced to improve the resolution, the reproducibility of the latent image formed from minute dots becomes more difficult, resulting in poor resolution and gradation, and sharpness. The image tends to be lacking in size.

Therefore, there has been proposed a toner intended to improve the image quality by regulating the particle size distribution of the developer to improve the reproducibility of fine dots.

Japanese Unexamined Patent Publication (Kokai) No. 2-284158 proposes a toner having an average particle size of 6 to 8 μm, and attempts to form a latent image of fine dots with good reproducibility by making the particle size fine. It was However, since the pressure of the fixing device is too strong and the heat is sufficiently applied in the heat roll fixing which has been frequently used in the past, the latent image of the fine dots formed with good reproducibility by the toner is crushed by the fixing roller. The resolution and gradation are disturbed, and the image lacks sharpness.

[0006] Further, Japanese Patent Laid-Open No. Sho 62-62 previously proposed by the present applicant.
In JP-A-147884, a fixing device that heats a toner image by a moving heat-resistant sheet by a heating element having a low heat capacity that is energized and heated in a pulse shape and fixes the toner image on a recording material has a short wait time and a low wait time. An image forming apparatus with low power consumption has been proposed, but an image with more excellent fine line reproducibility and gradation is required.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat fixing toner and a heat fixing method which solve the above problems.

That is, it is an object of the present invention to provide a heat fixing toner and a heat fixing method capable of obtaining a fixed image excellent in fine line reproducibility and gradation.

It is another object of the present invention to provide a heat fixing toner and a heat fixing method which are excellent in fine line reproducibility and resolution and which are favorably used for developing a digital latent image.

Further, the present invention is excellent in resolution, gradation, and fine line reproducibility even in an image forming apparatus which forms a latent image by a digital image signal and develops the latent image by a reversal development method. An object is to provide a heat fixing toner capable of forming a toner image and a heat fixing method.

[0011]

The heat fixing toner of the present invention comprises a heating member fixedly supporting a visible image of the toner on a recording material, and the heating member is pressed against the heating member so as to face the recording material. A heat-fixing toner used in a fixing method in which a material is heat-fixed by a pressure member that is brought into close contact with the heating body, wherein the toner has at least a weight average particle diameter of 4 to 8 μm and a particle diameter of 5 μm or less. 17 to 6 toner particles
5% to 50% by weight of toner particles having a particle diameter of 6.35 to 10.08 μm and 12.7%
Toner particles having a particle size of not less than μm are contained at 2.0% by volume or less, and a toner particle group of not more than 5 μm is expressed by the following formula

[0012]

[Outside 3] (In the formula, N represents the number% of the magnetic toner particles having a particle size of 5 μm or less, V represents the volume% of the toner particles having a particle size of 5 μm or less, and k represents a positive value of 4.6 to 6.7. The above object is achieved by having a particle size distribution satisfying the following condition: N is a positive number from 17 to 60.

The heat-fixing method of the present invention is a heat-fixing method in which a visible image of a toner is heat-fixed on a recording material, wherein the toner has at least a weight average particle diameter of 4 to 8 μm and a particle size of 5 μm.
17-60% by number of toner particles having a particle size of m or less, 5-50% by number of toner particles having a particle size of 6.35-10.08 μm, and a particle size of 12.7 μm or more The toner particles are contained in an amount of 2.0% by volume or less, and a toner particle group of 5 μm or less

[0014]

[Outside 4] (In the formula, N represents the number% of toner particles having a particle size of 5 μm or less, V represents the volume% of the toner particles having a particle size of 5 μm or less, and k is a positive number of 4.6 to 6.7. Indicates.
However, N represents a positive number of 17 to 60. ) Is satisfied, a toner image of the toner is fixedly supported on a recording material and a heating member fixedly supported on the recording material, and the recording material is covered with the recording material through a film. The above object is achieved by the feature that the fixing is performed by heating with a pressure member that is brought into close contact with a heating body.

That is, by making the particle size of the toner finer, a latent image of fine dots is formed with good reproducibility, and the heat-resistant sheet that moves by the low-heat-capacity heating element that has been energized and heated in the pulse shape described above is interposed. An image with excellent resolution and gradation, without using a fixing roller to crush the developer that forms a latent image of minute dots by using a fixing device that heats the toner visible image to fix it on the recording material. Can be obtained. Further, since the toner particle size is small, the fixing film is not damaged, and it is possible to prevent induction of toner fusion due to film damage, and it is possible to achieve higher image quality.

The particle size distribution of the toner can be measured by various methods, but in the present invention, it was measured using a Coulter counter.

That is, a Coulter counter TA-II type (manufactured by Coulter) is used as a measuring device, and an interface (manufactured by Nikkaki) for outputting number distribution and volume distribution and a CX-1 personal computer (manufactured by Canon) are connected. , The electrolyte is 1st grade sodium chloride
% NaCl aqueous solution is prepared. As a measuring method, a surfactant, preferably an alkylbenzene sulfonate, as a dispersant is added to 100 to 150 ml of the electrolytic aqueous solution in an amount of 0.1.
Add ~ 5 ml, and then add 2 to 20 mg of the measurement sample.
The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the Coulter counter TA-II type was used to measure the toner volume and number using a 100 μm aperture as an aperture. The volume distribution and number distribution of particles of -40 μm were calculated. Then, according to the present invention, the weight-based weight average diameter D ₄ obtained from the volume distribution (the median value of each channel is a representative value for each channel), and the weight-based coarse powder amount obtained from the volume distribution (2
0.2 μm or more), and the number-based fine powder number (6.35 μm or less) determined from the number distribution was determined.

Next, the developer applicable to the heat fixing system of the present invention will be described.

The developer according to the present invention preferably contains fine powder treated with silicone oil or silicon varnish, and its form is preferably a form in which the fine powder is dispersed on the surface of the developer.

The developer of the present invention having the above-mentioned constitution makes it more difficult for the developer to be fixed or scratched on the surface of the fixing film.

The material of the fine powder used in the present invention is preferably an inorganic compound. For example, fine powders of metal oxides of Group 3 and Group 4 such as silicic acid, alumina and titanium oxide are preferable. As preferable fine powders, both so-called dry method produced by vapor phase oxidation of a silicon halogen compound or dry silica called fumed silica and so-called wet silica produced from water glass or the like can be used. , fewer silanol groups on the inner surface and fine powder, and, Na ₂ O, who dry silica without producing residue, such as SO _^2-3 is preferred.

In the production process of dry silica, a composite fine powder of silica and another metal oxide can be obtained by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound in the manufacturing process. It is possible and includes them.

In the silicon oil treatment of the fine powder used in the present invention, by coating the surface of the fine powder with the silicone oil, the silanol groups can be completely covered and the moisture resistance is dramatically improved. ..

The silicone oil or silicone varnish solid content used in the present invention is generally represented by the following formula:

[0025]

[Outside 5]

(R: C ₁ , C ₂ , C ₃ alkyl group,
R ': alkyl, halogen-modified alkyl, phenyl, silicon-modified group such as modified phenyl, R ": C ₁ , C ₂ , C ₃
Alkyl group or alkoxy group), for example, dimethyl silicone oil, alkyl modified silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like.

The silicone oil is preferably 2
A viscosity of about 50 to 1,000 centistokes at 5 ° C. is used. Silicon oil whose molecular weight is too low may generate volatile components due to heat treatment,
On the other hand, if the molecular weight is too high, the viscosity becomes high and the treatment operation becomes difficult.

A known technique is used for the method of treating silicone oil. For example, fine powder and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or silicone oil may be sprayed onto the fine base powder. It may also depend on the method. Alternatively, it may be formed by forming a varnish and mixing it with the fine powder of the base, and then removing the solvent.

The present inventors believe that the developer according to the present invention exhibits the effects of the present invention as follows.
That is, since the form of the fine powder treated with silicon oil or silicon varnish is a surface coating type having a high coverage, it has excellent absorbability of mechanical impact force, and further has the fluidity and lubricity as fine powder. I also have it. Due to this characteristic, the mechanical pressure at the contact portion between the fixing film and the pressure member on the developer is relieved to prevent the dot-like or film-like fixing phenomenon on the surface of the fixing film, as well as scratches and scraping due to rubbing. It is presumed that it is preventing.

The particle size of the fine powder used in the present invention is 0.
001 to 2 μm is preferable, and 0.005 is particularly preferable.
.About.0.2 .mu.m is preferable.

Further, it is preferable that the fine powder used in the present invention is first treated with a silane coupling agent and then treated with silicone oil or silicone varnish.

In general, only with the silicone oil treatment, the amount of silicone oil for covering the surface of the fine powder is large, and agglomerates of the fine powder are likely to be formed during the treatment, and when applied to the developer, the fluidity of the developer is deteriorated. In some cases, it is necessary to pay close attention to the process of treating silicon oil.

Therefore, in order to prevent the fine powder from agglomerating while maintaining good moisture resistance, it is better to treat the fine powder with a silane coupling agent and then to treat it with silicone oil, in order to achieve a sufficient silicone oil treatment effect. It means that you can do it.

The silane coupling agent used in the present invention has a general formula R _m SiY _n (R: an alkoxy group or a chlorine atom, m: an integer of 1 to 3,
Y: an alkyl group, a vinyl group, a glycidoxy group, a methacryl group-containing hydrocarbon group, n: an integer of 3 to 1), and is typically dimethyldichlorosilane, trimethylchlorosilane, allyldimethyl. Chlorsilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxylane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane, dimethylvinylchlorosilane, etc. Can be done.

The treatment of the fine powder with a silane coupling agent is a dry treatment in which the vaporized silane coupling agent is reacted with a fine powder made into a cloud shape by stirring or the fine powder is dispersed in a solvent to obtain a silane coupling agent. It is possible to carry out the treatment by a generally known method such as a wet method in which the is reacted dropwise.

The amount of the silicone oil or silicon varnish solid content treated in the present invention is preferably 1 to 35 parts by weight, more preferably 2 to 30 parts by weight, based on 100 parts by weight of the fine powder. The reason for limiting the above treatment amount is that if the silicone oil treatment amount is too small, the same result as with the silane coupling agent treatment will not be obtained, and the moisture resistance will not improve, and fine powder will absorb moisture under high humidity, resulting in high quality. You will not be able to obtain a copy image of. Further, if the amount of silicone oil treated is too large, the agglomerates of the above-mentioned fine powder are likely to be formed, and remarkably free silicone oil is produced, so that the fluidity can be improved when applied to a developer. Defects such as not being possible occur.

Finally, it is desirable that the treated fine powder is hydrophobized so that the hydrophobization degree shows a value of 60% or more, more preferably 90% or more. If the degree of hydrophobicity is less than this, it becomes impossible to obtain a high-quality image due to water adsorption of the fine powder under high humidity.

For the hydrophobicity of the fine powder in the present invention, the value measured by the following method is used. Of course, other measuring methods can be applied while referring to the measuring method of the present invention.

100 ml of ion-exchanged water and 0.1 g of a sample were placed in a 200 ml separating funnel of a sealed stopper type, and the mixture was shaken (Turbra shaker mixer T2C type) at 90 rpm.
Shake for 10 minutes under the conditions. After shaking, the mixture was allowed to stand for 10 minutes, the fine powder layer and the water layer were separated, and then the lower water layer was added to 20-
30 ml was sampled, put in a 10 mm cell, and the transmittance was measured at a wavelength of 500 nm with reference to blank ion-exchanged water containing no fine powder, and the value of the transmittance was used as the degree of hydrophobicity of the fine powder. ..

Further, the application amount of these fine powders is effective when 0.01 to 20 parts by weight, based on 100 parts by weight of the developer base particles, more preferably 0.1 to 3 parts by weight is added. An excellent developer can be provided at the time. The preferred mode of addition is that the treated fine powder is in a state of being attached to the surface of the developer particles.

As the binder resin of the toner according to the present invention,
Polystyrene, homopolymers of styrene such as polyvinyltoluene and its substitution products; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene- Ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate acrylic acid copolymer, styrene-methacrylic acid Ethyl acid 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-based copolymers such as styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, polyacrylic acid resin, polyester resin, rosin, modified rosin, terpene resin , Phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, paraffin wax, carnauba wax and the like can be used alone or in combination.

Further, as a coloring material which can be further added to the developer according to the present invention, conventionally known carbon black,
Copper phthalocyanine, iron black, etc. can be used.

When the toner to be used is used as a magnetic toner containing magnetic fine particles, a substance which is placed in a magnetic field and magnetized is used as the magnetic fine particles.
Powders of ferromagnetic metals such as iron, cobalt and nickel, or alloys and compounds such as magnetite, γ-Fe ₂ O ₃ and ferrite can be used.

If desired, the toner of the present invention may contain a charge control agent, such as a metal complex salt of a monoazo dye,
A negative charge control agent such as a metal complex salt of salicylic acid, alkylsalicylic acid, dialkylsalicylic acid or naphthoic acid is used.

To the developer of the present invention, other additives such as Teflon, a lubricant such as zinc stearate, a fixing aid (for example, low molecular weight polyethylene), or a conductive agent may be added as long as they do not have a substantial adverse effect. A metal oxide such as tin oxide may be added as a property imparting agent.

Alternatively, colloidal silica as a fluidity improver may be contained in the toner in an amount of 10 to 40% by weight. Of course, the fluidity improver may be used by mixing it outside the toner, and the addition amount at that time is 0.2 to 5% by weight.
(Vs. toner weight).

In the production of the toner of the present invention, the constituent materials are well kneaded by a heat kneader such as a hot roll, a kneader or an extruder, and then mechanical pulverization or classification is used, or a binder resin solution is used. A method of obtaining the toner by dispersing the material and then spray-drying, or a polymerization method of obtaining a toner by mixing a predetermined material with a monomer that constitutes the binder resin to form an emulsion suspension and then polymerizing the mixture. Each method such as the method can be applied.

The heating element used in the fixing device in the present invention has a smaller heat capacity than the conventional heat roll and has a linear heating part, and the maximum temperature of the heating part is 100 to 3.
It is preferably 00 ° C.

The film located between the heating element and the pressing member is preferably a heat-resistant sheet having a thickness of 1 to 100 μm. These heat-resistant sheets include polyester having high heat resistance, PET (polyethylene terephthalate), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE
In addition to polymer sheets such as (polytetrafluoroethylene), polyimide and polyamide, a metal sheet such as aluminum and a laminated sheet composed of a metal sheet and a polymer sheet are used.

A more preferable film structure is that these heat resistant sheets have a release layer and / or a low resistance layer.

[0051]

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited thereto.

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

Reference numeral 11 denotes a low-heat-capacity linear heating element which is fixedly supported by the apparatus, and has a thickness of 1.0 mm and a width of 10 m as an example.
resistance material 1 on the alumina substrate 12 having a length of m and a length of 240 mm.
3 is applied to have a width of 1.0 mm, and electricity is applied from both ends in the longitudinal direction. Energization is a pulsed waveform with a cycle of 20 msec of DC 100 V and is given by varying the pulse width according to a desired temperature and energy release amount controlled by the temperature measuring element 14. Approximate pulse width is 0.5 msec
~ 5 msec. The fixing film 15 moves in the direction of the arrow in the drawing by coming into contact with the heating body 11 whose energy and temperature are controlled in this way. As an example of this fixing film, a heat-resistant film having a thickness of 20 μm, for example, polyimide, polyetherimide, PES, PFA, is coated with a release layer having a conductive material added to a fluororesin such as PTFE or PAF at least on the image contact surface side of 10 μm. It is an endless film. Generally, the total thickness is more than 100μ, preferably less than 40μ. The film is driven by the driving roller 16 and the driven roller 1.
Driven by 7 and tension, it moves in the direction of the arrow without wrinkles.

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

Although the endless belt has been described above, FIG.
As described above, the sheet feeding shaft 24 and the winding shaft 27 may be used, and the fixing film may be an end film.

The image forming apparatus is applicable to all fixing devices such as a copying machine, a printer, and a device for forming an image using toner such as Fax.

When the temperature detected by the temperature detecting element 14 in the low heat capacity linear heating element 11 is T ₁ , the surface temperature T ₂ of the film 15 facing the resistance material 13 is substantially equal to T ₁ .
The film surface temperature T _{3 at} the portion where the film 15 is peeled off from the toner fixing surface is substantially equal to the temperatures T ₁ and T ₂ .

The present invention will be described below with reference to examples, but the present invention is not limited thereto.

All parts in each example are parts by weight.

(Example 1) 100 parts of styrene-methyl acrylate copolymer 100 parts of magnetite 2 parts of monoazo chromium complex 3 parts of low molecular weight polypropylene

The above mixture was melt-kneaded with a twin-screw extruder heated to 130 ° C., the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was finely pulverized with a jet mill. Was classified with a fixed wall type air classifier to produce classified powder. Furthermore, the obtained finely divided powder was subjected to strict classification of ultrafine powder and coarse powder at the same time with a multi-division classifier utilizing the Coanda effect (Elbow Jet classifier manufactured by Nittetsu Mining Co., Ltd.) to obtain a weight average particle size of 6.5 μm. A black fine powder (magnetic toner) was obtained.

Table 1 below shows data obtained by measuring the magnetic toner, which is a black powder having a negative charging property, using the Coulter Counter TAII type having an aperture of 100 μ as described above.

[0063]

[Table 1]

Further, 100 parts of fine powder having a specific surface area of 200 m ² / g (Aerosil # 200, manufactured by Nippon Aerosil Co., Ltd.) was treated with 15 parts of hexamethyldisilazane (HMDS), and then dimethyl silicone oil KF-96 ( 100c
s, manufactured by Shin-Etsu Chemical Co., Ltd.) was treated with a solution diluted with a solvent, dried and then heat-treated at about 250 ° C. to obtain a treated fine powder having a hydrophobicity of 98%.

100 parts by weight of the toner and 1.0 of the silica
And 100 parts by weight after mixing with a Henschel mixer.
The powder that passed through the sieve of a mesh (Tiller mesh) was used as a negatively chargeable developer. Next, in the above-mentioned fixing device, the temperature detecting element surface temperature T ₁ of the heating element 11
Is 200 ° C, the power consumption of the resistance material of the heating part is 150W,
The total pressure between the heating element 11 and the pressure roller 21 was 13 kg, the nip between the pressure roller and the film was 3 mm, and the rotation speed of the fixing film 18 was 48 mm / sec.

Canon Laser Beam Printer LBP-
Image evaluation was performed using a modified machine of 8AJ1. At this time, the heat-resistant sheet has a P on the contact surface with the recording material.
A 20 μm-thick polyimide film having a low-resistance release layer in which a conductive substance is dispersed in TFE is used. At this time, the time required for the temperature measuring element surface temperature T _{1 of the} heating element to reach 185 ° C. is about 3 It was seconds. Furthermore, the temperature T ₂ is 18
A 3 ° C., the temperature T ₃ was 182 ° C..

Further, the surface of the laminated type organic photoconductor (OPC) photosensitive drum is subjected to primary charging of -700V, the potential at the exposed portion of the laser beam is set to -100V to form a digital latent image, and the DC bias is -500V. An AC bias (1800 Hz, peak to peak 1600 V) was applied, and the original image of the checker pattern shown in FIG. 3 was copied by the reversal development method. The closest gap between the developing sleeve (made of stainless steel) and the photosensitive drum in the developing section is set to 300 μm, and the layer thickness of the developer layer on the sleeve in the developing section in a state where no bias is applied is set to about 100 μm. It was developed.

Room temperature and normal humidity (25 ° C, 60% RH), high temperature and high humidity (30 ° C, 90% RH) and low temperature and low humidity (15 ° C, 10%)
% RH), a good copy image was obtained, and the checkered toner image in FIG. 3 had no defect.

Under each environment, a continuous printout test of 4,000 sheets was carried out. As a result, the toner image density was maintained at 1.36 or more and the fine line reproducibility was excellent.
Further, neither scratch nor scraping on the surface of the fixing film was observed. The toner particle size is shown in Table 2, and the image evaluation result is shown in Table 3.

(Example 2) 80 parts of styrene-butyl acrylate copolymer 20 parts of styrene-butyl methacrylate-monobutyl maleic acid copolymer 100 parts of magnetite 100 parts of chromium complex salt of di-tert-butylsalicylic acid 3 parts-Phthalocyanine pigment 3 parts-Low molecular weight polypropylene 4 parts

Using the above mixture, a black fine powder was obtained in the same manner as in Example 1.

Further, 100 parts of a fine powder (Aerosil # 130, manufactured by Nippon Aerosil Co., Ltd.) having a specific surface area of 130 m ² / g was treated with 15 parts of dimethyldichlorosilane, and then dimethyl silicone oil KF-96 (100 cs) 5 Part was treated in the same manner as in Example 1 to obtain a treated fine powder having a hydrophobicity of 94%.

To 100 parts by weight of the above black fine powder, 1.4 parts by weight of the treated fine powder was added in the same manner as in Example 1 to obtain a toner, and image evaluation was carried out. The image density of the toner was 1.38. The above was maintained and the fine line reproducibility was excellent. Again 3
The surface of the fixing film was not scratched or scraped even after 500 sheets had been run. The toner particle size is shown in Table 2 and the image evaluation results are shown in Table 3 as in Example 1.

Example 3 100 parts by weight of a polyester resin obtained by condensing a proxy bisphenol and fumaric acid 100 parts by weight of magnetite 3 parts of a monoazo chromium complex 3 parts of a low molecular weight polypropylene 3 parts

Using the above mixture and the treated silica of Example 1, a toner was obtained in the same manner as in Example 1 and image evaluation was carried out. The toner image density was 1.
The value of 35 or more was maintained and the fine line reproducibility was excellent. Also, the fixing film was not scratched or scraped. The particle size of the toner is shown in Table 2 and the image evaluation results are shown in Table 3 as in Example 1.

Comparative Example 1 Image evaluation was performed in the same manner as in Example 3 except that the particle size distribution of the toner was changed.
The image density after running 000 sheets was 1.30, and the reproducibility of fine lines was at a level of about 6 to 10 defects. Further, although not so bad as to find an adverse effect on the image, some abrasion was observed on the fixing film.

[0077]

[Table 2]

[0078]

[Table 3] N / N: Normal temperature and normal humidity (23.5 ° C, 60%) H / H: High temperature and high humidity (32.5 ° C, 85%) L / L: Low temperature and low humidity (15.0 ° C, 10%) Black dots Reproducibility of 100: ○: 2 or less defects ○ △: 3 to 5 defects Δ ... 6 to 10 defects × ... 11 or more defects

[0079]

As described above, the present invention improves the fine line reproducibility of the latent image of fine dots by making the particle size of the toner fine, and by the heat fixing method using a heat resistant sheet, It is possible to obtain an image excellent in resolution and gradation without crushing the latent image and damaging the heat resistant sheet.

[Brief description of drawings]

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

FIG. 2 is a structural view of another embodiment of the fixing device according to the present invention.

FIG. 3 shows a checker pattern toner image used for image evaluation.

[Explanation of symbols]

 11 Low Heat Capacity Linear Heater 12 Alumina Substrate 13 Resistance Material 14 Thermometric Element 15 Fixing Film 16 Drive Roller 17 Driven Roller 18 Pressure Roller 19 Transfer Material 20 Unfixed Toner 21 Entrance Guide

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukari Ishibashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (2)

[Claims] 1. A heat-fixing method comprising a heating member fixedly supporting a toner image on a recording material, and a pressure member that is pressed against the heating member so as to face the recording material, and presses the recording material to the heating member through a film. In the heat fixing toner used in the fixing method described above, the toner has at least a weight average particle diameter of 4 to 8 μm, and 17 to 6 toner particles having a particle diameter of 5 μm or less.
5% to 50% by weight of toner particles having a particle diameter of 6.35 to 10.08 μm and 12.7%
Toner particles having a particle size of μm or more are contained in an amount of 2.0% by volume or less, and a toner particle group of 5 μm or less is expressed by the following formula: (In the formula, N represents the number% of the magnetic toner particles having a particle size of 5 μm or less, V represents the volume% of the toner particles having a particle size of 5 μm or less, and k represents a positive value of 4.6 to 6.7. The heat fixing toner is characterized in that it has a particle size distribution satisfying the following condition: N is a positive number from 17 to 60. 2. A heat fixing method for heat fixing a visible image of a toner on a recording material, wherein the toner has at least a weight average particle diameter of 4 to 8 μm and toner particles having a particle diameter of 5 μm or less are 17 to 60. Contained in a number of%, 6.35-1
5 to 50% by number of toner particles having a particle size of 0.08 μm are contained, 2.0% by volume or less of toner particles having a particle size of 12.7 μm or more are contained, and a toner particle group of 5 μm or less is represented by the following formula. [Outside 2] (In the formula, N represents the number% of toner particles having a particle size of 5 μm or less, V represents the volume% of the toner particles having a particle size of 5 μm or less, and k is a positive number of 4.6 to 6.7. Indicates.
However, N represents a positive number of 17 to 60. ) Is satisfied, a visible image of the toner is fixedly supported on a recording material, and the recording material is fixedly supported by the recording material through a film. A heat-fixing method, characterized in that heat-fixing is performed by using a pressure member that is brought into close contact with a heating body.