JPH0812460B2 - Heat fixing method and heat fixing capsule toner used in the method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fixing method and toner used in electrophotography, electrostatic printing, magnetic recording, etc., and more particularly, to fixing a toner image on a recording material by heating. And a capsule toner used in the fixing method of the image forming apparatus.

[Prior Art] Conventionally, as a method for fixing a visible image of a toner on a recording material, it is undetermined by using a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer and being in pressure contact with the heating roller. A heat roll fixing method is often used in which a recording material holding a visible toner image is heated while being nipped and conveyed.

Further, a belt fixing method described in USP 3,578,797 is known.

[Problems to be Solved by the Invention] However, in the above-described thermal roll fixing which has been frequently used, there is (1) a time for which the image forming operation is prohibited until the heat roller reaches a predetermined temperature, that is, a so-called wait time.

(2) In order to prevent fixing failure and transfer of toner to the heating roller due to the temperature of the heating roller fluctuating due to passage of the recording material or other external factors, so-called offset phenomenon, the heating roller is set to an optimum temperature. It is necessary to maintain this, and for this purpose, the heat capacity of the heating roller or the heating body must be increased, which requires a large amount of electric power.

(3) Since the temperature of the roller is low, when the recording material passes through the heating roller and is discharged, the recording material and the toner on the recording material are cooled slowly, so that the toner has a high adhesiveness. In combination with the curvature of, the paper may be jammed due to the offset or winding of the recording material.

(4) Since the high-temperature heating roller is in direct contact with the hand, there is a problem in safety or a protective member is required. Also, in the belt fixing method described in USP 3,578,797, the problems (1) and (2) of the heat roll fixing described above have not been fundamentally solved.

An object of the present invention is to substantially eliminate the wait time for solving the above-mentioned problems, or an extremely short time,
Further, the present invention provides a novel heating and fixing method which has low power consumption, does not cause an offset phenomenon, and is excellent in fixing a toner image on a recording material.

Further, an object of the present invention is to provide a heat fixing toner which is preferably used in the heat fixing method provided in the present invention.

Still another object of the present invention is to provide a heat fixing method that does not require a heat resistant special bearing by not using a high temperature rotating roller.

Still another object of the present invention is to provide a heat fixing method which is excellent in safety or does not require a protective member by having a fixing device structure in which the high temperature body is not directly touched.

[Means for Solving the Problem] In Japanese Patent Application No. 62-147884 previously proposed by the present applicant, a toner image is generated through a moving heat-resistant sheet by a low heat capacity heating element that is energized and heated in a pulse shape. An image forming apparatus having a short wait time and low power consumption has been proposed by a fixing device that heats an image and fixes it on a recording material. Similarly, Japanese Patent Application No. 63-1206 previously proposed by the applicant.
In 9, in the fixing device for heating and fixing the visible image of the toner on the recording material via the heat resistant sheet, the heat resistant sheet has a heat resistant layer and a release layer or a low resistance layer,
A fixing device has been proposed that effectively prevents the offset phenomenon.

However, in order to realize a fixing method that has a short wait time and low power consumption while achieving excellent fixability of a toner image on a recording material, prevention of offset, etc., the fixing device as described above is used. In addition, the characteristics of the toner largely depend.

The present invention that achieves the above object is a method of using a capsule toner having a core material and a shell material that covers the core material to heat and fix a visible image of the capsule toner on a recording material, wherein a) the binder resin is a binder resin. , Has a magnetic substance and carbon black, and the carbon black has an average particle size of 10 to 80 m.
having a thickness of 1 μm and being contained in the core material in a proportion of 1 to 30% by weight of the core material, and b) a fixedly supported heating element, and the recording material is pressed against the heating element in opposition and through a film. A pressure member that brings the material into close contact with the heating body heat-fixes the visible image of the toner on the recording material, and the film is removed from the toner-fixed surface at a temperature higher than the maximum value of the endothermic peak measured by the DSC of the toner. It relates to a heat fixing method characterized by peeling.

Further, a fixed image of the toner is heated and fixed on the recording material by a fixedly supported heating element and a pressing member that is in pressure contact with the heating element and brings the recording material into close contact with the heating element via a film. In the toner used in the heat fixing method of peeling the film from the toner fixing surface at a temperature higher than the maximum value of the endothermic peak measured by DSC, the toner has a core material and a shell material covering the core material. An encapsulated toner in which the core material has a binder resin, a magnetic material and carbon black, and the carbon black has an average particle size of 10 to 10
The present invention relates to a heat fixing capsule toner, which has a particle size of 80 mμm and is contained in the core material in an amount of 1 to 30% by weight of the core material.

The toner used in the heat fixing method of the present invention is a capsule type toner. Generally, the capsule-type toner has a form in which a core material containing a binder resin, a colorant and the like is coated with a shell material, and is excellent in fluidity and charging characteristics due to a uniform shell material coating. In addition, since it is protected by the shell material, it has excellent blocking properties and storage stability, and it is possible to add a substance that softens at a lower temperature to the core material, which improves the fixing property and further improves the substantial fixing temperature. It is possible to lower it.

As the binder resin material used for the core material of the encapsulated toner of the present invention, various known resins can be used alone or mixed or reacted. For example, homopolymers of polystyrene and its substitution products: styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylonitrile copolymer, styrene-
Butadiene copolymer, styrene-isoprene copolymer,
Styrene-copolymer such as styrene-acrylonitrile-indene copolymer: acrylic resin, methacrylic resin,
Examples include silicone resins, polyester resins, furan resins, epoxy resins, and the like.

Further, a binder material for pressure fixing or low temperature fixing can also be used. For example, waxes (beeswax, carnauba wax, microcrystalline wax, etc.), higher fatty acids (stearic acid, palmitic acid, lauric acid, etc.), higher fatty acid metal salts (aluminum stearate,
Lead stearate, barium stearate, magnesium stearate, zinc stearate, zinc palmitate, etc.), higher fatty acid derivatives (methyl hydroxy stearate, glycerol monohydroxy stearate, etc.),
Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, polyisobutylene, polytetrafluoroethylene, etc.), olefin copolymer (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid) Copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer resin, etc.), rubbers (isobutylene rubber, nitrile rubber, chlorinated rubber, etc.), polyvinylpyrrolidone , Polyamide, coumarone-indene resin, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, and the like, and these can be used alone or in a mixture or in a reaction.

In order to use the toner as a magnetic toner, a magnetic powder may be contained in the core material. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used.
There are powders of ferromagnetic metals such as iron, cobalt and nickel, or alloys and compounds such as magnetite, hematite and ferrite. The content of the magnetic powder is preferably from 15 to 70% by weight based on the weight of the toner.

The magnetic material may be subjected to hydrophobic treatment with a known coupling agent before use. Examples of such coupling agents include silane coupling agents, titanium coupling agents, aluminum coupling agents, zirconium coupling agents, and the like. The treatment amount is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the magnetic material.

Examples of carbon black used for the toner used in the heat fixing method of the present invention include RAVEN5000, RAVEN7000, RAVEN5750, RAVEN3500, and RAVEN210 of Columbia Carbon Co.
0, RAVEN1800, RAVEN1500, RAVEN1250, RAVEN1200, RAVEN117
Examples include 0. The average particle size of these carbon blacks must be 10-80 mμm, especially 10-30 mμm.
m is preferable, and the amount used is 1 to 30% of the core material.
It is particularly preferable to use it in a proportion of 2 to 15%.

In the present invention, the core material of the capsule toner is obtained by melt-kneading the above components with, for example, a roll mill, pulverizing with a jet mill or the like, and classifying them with an air classifier if necessary. Further, after the melt-kneading, the volume average particle diameter is obtained by granulating by a spray method, a suspension granulation method, an electrostatic atomization method or the like, and classifying as necessary.
It is prepared as fine particles of 20 μm or less.

As a method for encapsulating these core particles, a known encapsulation technique can be used. For example, spray drying method, coacervation method, phase separation method and the like can be preferably used, in-situ polymerization method, U.S. Pat.
No. 8,991, No. 3,326,848, No. 3,502,58
The method described in No. 2 specification and the like can also be used.

A known resin can be used as the shell material. For example, there are resins composed of the following monomers. Styrene, styrene such as P-chlorostyrene, P-dimethylamino-styrene and the like, and substituted products thereof; methyl acrylate,
Ester of acrylic acid or methacrylic acid such as ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylic acid N, N-dimethylaminoethyl ester; maleic anhydride or half ester of maleic anhydride , Half amide or diester imide, vinyl pyridine, N
-Nitrogen-containing vinyl such as vinylimidazole; vinylacetal such as vinylformal and vinylbutyral; vinyl monomers such as vinyl chloride, acrylonitrile and vinyl acetate; vinylidene monomers such as vinylidene chloride and vinylidene fluoride; olefin monomers such as ethylene and propylene. is there. Also, polyester, polycarbonate, polysulfonate, polyamide, polyurethane, polyurea, epoxy resin, rosin, modified rosin,
Homopolymers or copolymers of terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, melamine resins, polyether resins such as polyphenylene oxide or thioether resins, or copolymers, and further Mixtures thereof can be used.

The capsulated toner of the present invention can be used as a developer after mixing a fluidity improver such as colloidal silica, a lubricant, an abrasive, a charge adjusting agent, etc., depending on the case.

When used as a two-component developer, it is used as a developer after being mixed with an iron powder carrier, a ferrite carrier, a carrier obtained by coating these with a silicone resin, an acrylic resin or the like, or a carrier having a magnetic material dispersed in a resin. .

In the heat fixing method of the present invention, since a large amount of carbon black is contained in the toner, the image density after heat fixing is higher than that obtained by coloring only the magnetic material. Furthermore, the blackness is also high. Not only that, when a binder having a low softening point for heat fixing is used or when a sharp-melting binder is used, by adding a magnetic material and carbon black, image bleeding at the time of fixing and transfer material ( It is also possible to reduce the soaking into paper). Further, since excessive thermal deformation of the toner particles can be suppressed, it is also effective for offsetting to the fixing film. Further, since the capsule structure prevents the blocking property of the toner particles, it is possible to relatively lower the minimum fixing temperature of the toner, and in the heat fixing method of the present invention, good fixing property can be obtained with low energy.

 Next, the fixing method of the present invention will be described.

First, a schematic structure of an example of the image forming apparatus of the present invention will be described below.
It will be described with reference to the drawings. Reference numeral 1 denotes an original placing table made of a transparent member such as glass, which reciprocates in the direction of arrow a to scan the original. Immediately below the document table, a short-focus small-diameter imaging element array 2
The image of the original placed on the original table is illuminated by the illumination lamp 3, and the reflected light image is slit-exposed on the photosensitive drum 4 by the array 2. The photosensitive drum rotates in the direction of arrow b. Reference numeral 5 denotes a charger, which uniformly charges the photosensitive drum 4 covered with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. The drum 4 uniformly charged by the charger 5 is
The element array 2 forms an electrostatic image subjected to image exposure. This electrostatic latent image is visualized by the developing device 6 by using a toner made of a resin or the like which is softened and melted by heating. On the other hand, the sheets P stored in the cassette S are
It is fed onto the drum 4 by a pair of conveying rollers 8 which are rotated in pressure contact with each other in the vertical direction at a timing synchronized with the feeding roller 7 and the image on the photosensitive drum 4. Then, the transfer discharger 9 transfers the toner image formed on the photosensitive drum 4 onto the sheet P. afterwards,
The sheet P separated from the drum 4 by a known separation unit is guided to the fixing device 11 by the conveyance guide 10 and is heated and fixed, and then discharged onto the tray 12. After the toner image is transferred, the residual toner on the drum 4 is removed by the cleaner 13.

FIG. 2 (a) shows an enlarged view of the fixing device 11 of the present invention.
Reference numeral 20 denotes a low-heat-capacity linear heating element that is fixedly supported by the device, and as an example, an alumina substrate 21 having a thickness of 1.0 mm, a width of 10 mm, and a length of 240 mm is coated with a resistance material 22 in a width of 1.0 mm. Power is applied from both ends. Energization is DC 100V, cycle 20mse
A pulse having a pulse-like waveform of c, which is controlled by the temperature measuring element 23 according to a desired temperature and energy release amount, is given by changing its pulse width. Approximate pulse width is 0.5 msec
~ 5msec. When the temperature detected by the temperature measuring element 23 in the low heat capacity linear heating element 20 is T ₁ , the surface temperature T ₂ of the film 24 facing the resistance material 22 is lower than T ₁ by about 10 to 30 ° C.
The film surface temperature T _{3 at} the portion where the film 24 is peeled off from the toner fixing surface is substantially equal to the temperature T ₂ .

In this way, the fixing film 24 moves in the direction of the arrow in the drawing by coming into contact with the heating body 20 whose energy and temperature are controlled. As an example of this fixing film, a heat-resistant film with a thickness of 20 μm,
For example, it is an endless film obtained by coating a release layer of polyimide, polyetherimide, PES, PFA with a conductive material added to a fluororesin such as PTFE, PAF or the like on at least the image contact surface side to a thickness of 10 μm. Generally, the total thickness is 100μ, preferably 40μ
Less than, film drive is driven roller 25 and driven roller 26
It moves without wrinkles in the direction of the arrow by the drive and tension.

Reference numeral 27 is a pressure roller having a rubber elastic layer having a good releasability such as silicon rubber, which presses a heating body through the film at a total pressure of 4 to 20 kg to rotate in pressure contact with the film.

The unfixed toner 29 on the transfer material 28 is guided to the fixing portion by the entrance guide 30 and obtains a fixed image by the above-mentioned heating.

Although the endless belt has been described above, as shown in FIG. 2 (b), a sheet feeding shaft 31 and a winding shaft 32 may be used, and the fixing film may be an end film 24.

Image forming devices include copiers, printers and fax machines.
This is applicable to all fixing devices that form an image using toner such as.

In the heat fixing method of the present invention, the toner used has a maximum value of the endothermic peak first appearing from 40 ° C. to 120 ° C. as a result of measurement by DSC in a measuring range from 10 ° C. to 200 ° C.
A toner having a temperature of 55 ° C. is preferable, and a toner having a characteristic of 55 ° C. to 100 ° C. is particularly preferable.

Further, the temperature at the time of peeling the film from the toner fixing surface is required to be higher than the endothermic temperature, and is 30 ° C. or more (more preferably 40 to 40 ° C.) higher than the endothermic temperature.
It is preferable to peel under high conditions (150 ° C).

The maximum value of the endothermic peak in the present invention is calculated according to ASTM D-3418-82. In particular,
10 to 15 mg of toner is sampled from room temperature to 200 ° C under a nitrogen atmosphere.
After heating at a heating rate of 10 ° C / min to 200 ° C for 10 minutes, and then rapidly cooling the toner to pretreat it in advance, then holding it again at 10 ° C for 10 minutes, then 10 ° C. / m
Measure up to 200 ℃ at a heating rate of in. In general,
The data shown in FIG. 3 is obtained, and the maximum value of the endothermic peak that appears first is defined as the endothermic temperature (T _D ) in the present invention.

[Example] A toner sample was prepared by the following method. The number of parts means parts by weight.

(Sample A) The above components were melt-kneaded using a roll mill, cooled, coarsely pulverized with a cutter mill, and then finely pulverized with a jet mill. Then, the finely pulverized product was classified by an elbow jet to obtain core material particles having an average particle size of 10.2 μm. Then, encapsulation was performed by the following method.

After being sufficiently dispersed as a mixture of the above composition, when spray atomized with a spray nozzle device equipped with a disk atomizer, there was no coalescence of particles, and when observed by SEM, there was no coalescence of particles, depending on the shell material. A capsule toner was obtained which exhibited a smooth surface morphology that was completely covered.

For 100 parts of this toner, hydrophobic colloidal silica 0.4
The department was added externally. This is designated as Sample A.

(Sample B) The above components were kneaded, pulverized and classified in the same manner as in Sample A to obtain core material particles having an average particle diameter of 11.3 μm.

This was encapsulated in the same manner as Sample A. However, the shell material was 0.9 parts.

For 100 parts of this toner, hydrophobic colloidal silica 0.4
Externally mixed. This is sample B.

(Sample C) The above components were kneaded, pulverized and classified in the same manner as in Sample A to obtain core material particles having an average particle size of 10.4 μ.

 This was encapsulated in the same manner as Sample A.

For 100 parts of this toner, hydrophobic colloidal silica 0.4
Parts were externally mixed. This is sample C.

Next, a fixing test was conducted using the heat fixing devices shown in Samples A to C and FIG. 2 (a). Further, a blocking property test was also conducted.

<Embodiment 1> In this fixing device, the surface temperature of the heating element is 150 ° C., the power consumption of the resistance material in the heating portion is 150 W, the total pressure of the pressure roller is 7 kg, the nip between the pressure roller and the film is 3 mm, and the fixing process is performed. The speed (ps) was set to 100 mm / sec. As the heat-resistant sheet, a polyimide film having a thickness of 20 μm having a low-resistance release layer in which a conductive material was added to PTFE was used on the contact surface with the recording material.

At this time, the time required to reach the surface temperature of the heating body of 150 ° C. was about 1.4 sec.

Sample A was applied to an improved machine of the commercial copying machine Canon NP-150Z (manufactured by Canon Inc.) from which the fixing device was removed to obtain an unfixed image.

This unfixed image was subjected to a fixing test under the above conditions using an external fixing machine as shown in FIG. 2 (a).

A commercially available Canon New Dry Paper (manufactured by Canon Sales Co.) 54 g / m ² was used as the transfer material.

In the fixing test, a solid black portion of 20 mmφ in the obtained fixed image was rubbed with a sillbon paper applied with a load of 50 g / cm ² , and the image density reduction rate (%) before and after the rubbing was expressed. A Macbeth reflection densitometer was used to measure the image density. Further, the unfixed image taken out from the modified machine is continuously passed through the external fixing tester in order to check the offset resistance, and the fixing film and the opposing roller are stained, the image is removed by the offset, and the transfer material is transferred onto the image. Judgment was made by observing dirt and dirt on the back side of the transfer material.

As a result, the fixing property was as good as 1 to 5% (average 2.1%) at the initial stage and after passing 200 sheets. Further, the offset resistance was such that, even after passing 10,000 unfixed images, neither stain on the transfer paper nor stain on the back side of the transfer paper was observed at all. Further, when the film of the fixing device and the surface of the facing roller were observed after continuous paper passing, almost no toner adhered.

Furthermore, 10 g of this toner was placed in a polypropylene 100 cc cup in an oven with a tank temperature of 45 ° C (constant).
When the toner containing the toner was left for 1 day and the blocking property was observed, no toner lumps were generated and it was good.

Comparative Example 1 The following test was attempted in order to compare the present heat fixing device with the heating roller fixing device. An external fixing device for fixing with a heat roller was prepared. The heat roller fixing device is composed of two rolls, an upper roller and a lower roller, the surface of the upper roller is Teflon, a heater is arranged at the center thereof, and the lower roller is made of silicon rubber. Furthermore, the nip width is 3 mm. The total pressure between the rollers was 7 kg.

When a heater with power consumption of 150 W was attached to the center of the heat roller and the temperature was raised while rotating the roll, the surface temperature rose to 160 ° C. even after 5 minutes, and the fixing test could not be performed. Therefore, we changed the heater to 900W and made it possible to maintain the surface temperature of the fixing roller at 150 ° C or higher. At this time, the time required for the surface temperature of the heat roller to rise from room temperature to 150 ° C. was 17.5 seconds, and it took some time to be kept at a constant temperature by temperature control. That is,
The heat roll fixing requires extremely high power consumption, and the wait time cannot be eliminated.

The fixing test was performed using a heat roll external fixing tester equipped with a 900 W heater, with the oil applying mechanism and the cleaning mechanism of the fixing roller being removed. The fixing processing speed was 100 mm / sec, which was the same as in Example 1.

As a result, the fixability was inferior to that in Example 1 as the density reduction rate was 4 to 11% (average 5.5%) at the initial stage and after 200 sheets, and when 200 sheets were passed, the image on the image already subjected to the offset development was already formed. Omission was observed, and the backside was stained at 1100 sheets. Further, when the roller surface was observed after continuous paper passing, a considerable amount of toner had adhered.

<Example 2> In Example 1, a fixing test was conducted by changing the fixing processing speed to 150 mm / sec. However, the surface temperature of the heating element is 180 ° C
It was set to become. At this time, the surface temperature of the heating
The time required to reach 0 ° C was about 27 sec. The results of the fixing test are shown in Table 1. Good results were shown as shown in Table.1.

<Comparative Example 2> The external fixing tester using the hot roll used in Comparative Example 1 was used, and the fixing processing speed was 150 mm / se for comparison with Example 2.
c, and the roller surface temperature was set to 180 ° C.
At this time, the time required for the roller surface temperature to reach 180 ° C. was about 27 seconds.

The results are shown in Table.1. As shown in Table.1, the results are inferior in fixing property and offset property.

<Example 3> Using toner sample B, a fixing test and a toner blocking test were performed in the same manner as in Example 1. Table 1 summarizes the test conditions and test results.

Comparative Example 3 Using toner sample B, a fixing test was performed in the same manner as in Comparative Example 1. Test conditions and test results
It is shown in ble.1.

<Example 4> Using toner sample C, a fixing test and a toner blocking test were performed in the same manner as in Example 1. Table 1 summarizes the test conditions and test results.

<Comparative Example 4> Using toner sample C, a fixing test was performed in the same manner as in Comparative Example 1. Test conditions and test results
It is shown in ble.1.

Table ₂ shows the endothermic temperature (T _D ) by DSC, the heating body temperature (T ₁ ), the film surface temperature (T ₂ ), and the film surface temperature at the time of peeling (T ₃ ) of the toner sample shown in the examples of the present invention.
Shown in

[Advantages of the Invention] As described above, according to the heat fixing method of the present invention, an image having good fixability can be obtained with less power consumption, no offset.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an image forming apparatus having a fixing device that carries out the fixing method of the present invention, and FIG. 2 (a) shows a fixing device for carrying out the fixing method of the present invention. FIG. 2 (b) shows a schematic sectional view of a fixing device for carrying out the fixing method of another embodiment of the present invention.
FIG. 3 is a graph showing the endothermic peak of the toner.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G03G 9/09 13/20 15/20 101 G03G 9/08 (72) Inventor Satoshi Matsunaga Ota, Tokyo 3-30-2 Maruko Shimoshita, Canon Inc. (56) References JP-A-59-68766 (JP, A) JP-A-59-157678 (JP, A) JP-A-62-280759 (JP, A) ) JP-A-62-75543 (JP, A) JP-A-60-147748 (JP, A)

Claims (4)

[Claims] 1. A method of heat-fixing a visible image of a capsule toner on a recording material by using a capsule toner having a core material and a shell material covering the core material, comprising: a) a binder resin, a magnetic material, and It has carbon black, and the carbon black has an average particle size of 10 to 80 m.
having a thickness of 1 μm and being contained in the core material in a proportion of 1 to 30% by weight of the core material, and b) a fixedly supported heating element, and the recording material is pressed against the heating element in opposition and through a film. The toner image is heat-fixed on the recording material by a pressure member that brings the material into close contact with the heating body, and a film is formed from the fixing surface of the toner at a temperature higher than the maximum value of the endothermic peak measured by the DSC of the toner. A heat fixing method, which comprises peeling. 2. The heat fixing method according to claim 1, wherein the temperature at which the film is peeled off from the toner fixing surface is higher than the maximum value of the endothermic peak measured by DSC of the toner by 30 ° C. or more. 3. A toner image is heat-fixed to a recording material by a fixedly supported heating element and a pressing member that is in pressure contact with the heating element and brings a recording material into close contact with the heating element via a film. However, in the toner used in the heat fixing method of peeling the film from the toner fixing surface at a temperature higher than the maximum value of the endothermic peak measured by the DSC of the toner, the toner is a core material and a shell covering the core material. A capsule toner having a material, wherein the core material has a binder resin, a magnetic material and carbon black, and the carbon black has an average particle size of 10
A heat-fixing capsule toner having a particle size of ˜80 mμm and being contained in the core material in an amount of 1 to 30% by weight of the core material. 4. The heat fixing capsule according to claim 3, wherein the temperature at which the film is peeled from the toner fixing surface is higher than the maximum value of the endothermic peak measured by DSC of the toner by 30 ° C. or more. toner.