JP3032535B2 - Dry heat roller fixing toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to dry development used for visualizing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like. More specifically, the present invention relates to a toner for fixing a hot roller with dry heat.

[Prior Art] Conventionally, various methods of electrophotography have been described in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 49-23210, Japanese Patent Publication No. 43-24748, and the like. Using a photoconductive material, an electric latent image was formed on the photoconductive material by various means, and then the latent image was developed using toner, and the toner image was transferred to paper or the like as necessary. After that, the image is fixed by heating, pressurizing, a solvent, steam, or the like to obtain a copy.

There are oven fixing method, flash fixing method, heat roller fixing method, etc. as a method for thermally fixing the toner image developed from the electric latent image. The heat roller fixing method is an image of a sheet to be fixed such as paper on a roller surface. Since thermal efficiency is high due to pressure contact with the surface, it is extremely advantageous for high-speed copying and the like, and is widely and generally used.

However, this method has a disadvantage in that the toner is in contact with the roller in a molten state, so that the toner adheres to the roller surface, and a hot offset phenomenon in which the adhered toner adheres to the sheet to be fixed due to rotation of the roller easily occurs. doing.

As a method for solving this problem, there has been proposed a method of adding low molecular weight polypropylene to the toner (see Japanese Patent Application Laid-Open No. 49-65231).

However, the toner to which the low molecular weight polypropylene is added has the drawbacks that the fluidity and the cohesiveness are remarkably reduced, and that the so-called spent phenomenon in which the toner sticks to the carrier surface is easily caused.

As a method for improving the fluidity and cohesiveness of the toner, there is a method of adding a fluidity improver such as silica and titanium oxide, but these fluidity improvers reduce the charge amount of the toner in a high humidity state. As a result, the background image becomes dirty and the image density becomes excessive when the humidity is high, and the quality of the copied image is remarkably deteriorated.

Further, as a method of preventing the toner from being spent, there is a method of coating the surface of a charge providing member such as a carrier with a low surface energy substance.
Although tetrafluoroethylene compounds, silicone resins, polymethyl methacrylate polymers and the like have been used,
It is still insufficient for spent toner containing a low molecular weight polypropylene.

[Problems to be Solved by the Invention] The present invention aims to solve the above-mentioned conventional disadvantages, and in particular, the fluidity, cohesiveness,
An object of the present invention is to provide a dry heat roller fixing toner in which hot offset is prevented and heat fixability is improved without impairing various characteristics such as spent property with respect to a carrier.

[Means for Solving the Problems] The present inventors have been conducting research in the past to solve the above-mentioned problems, and as a result, heating at least particles containing a binder resin and low molecular weight polypropylene, The present inventors have found that it is effective to precipitate low molecular weight polypropylene on the particle surface, and have reached the present invention.

That is, the present invention provides: (1) a toner in which low molecular weight polypropylene is deposited near the particle surface by applying heating, frictional heat or both heats simultaneously to particles comprising at least a binder resin and low molecular weight polypropylene; A hot offset generating temperature of 210 ° C. to 250 ° C., wherein the non-magnetic toner for fixing a hot roller is a non-magnetic toner; A method for producing a toner comprising mixing polypropylene and then applying heating, frictional heat or both heats simultaneously to the obtained particles, wherein the temperature of the heat is 35 ° C to 55 ° C. A method for producing a non-magnetic toner for fixing by a dry heat roller, (3) particles having at least a binder resin and a low-molecular-weight polypropylene, and having a smaller particle size than the particles. A toner in which low molecular weight polypropylene is deposited near the surface of particles by heating, frictional heat or both heats simultaneously applied to the particles mixed with the hard inorganic fine powder, and the hard inorganic fine powder is further fixed on the surface. , Hot offset occurrence temperature is 21
(4) A method for producing a toner for fixing a hot roller, wherein the binder resin and low-molecular-weight polypropylene are mixed and then obtained. And a hard inorganic fine powder having a smaller particle size than the particles, and further applying heating, frictional heat or both heats simultaneously to the mixed particles, the method comprising: A method for producing a non-magnetic toner for fixing by a dry heat roller, wherein the temperature is 35 ° C. to 55 ° C .; (5) at least particles comprising a binder resin and low molecular weight polypropylene; By applying heating, frictional heat or both heats simultaneously to the particles mixed with the hard inorganic fine powder having, the low molecular weight polypropylene is precipitated near the surface of the particles, and the hard inorganic fine powder is further deposited on the surface. And (6) production of a toner for fixing with a hot roller and a toner for fixing with a hot roller, characterized by mixing particles obtained by adhering the particles with a hard inorganic fine powder having the same composition as the fixed hard inorganic fine powder. In the method, at least a binder resin and low molecular weight polypropylene are mixed, then the obtained particles are mixed with a hard inorganic fine powder having a smaller particle size than the particles, and the mixed particles are further heated, heated by friction or both. Characterized by mixing a hard inorganic fine powder having the same composition as the inorganic fine powder with particles obtained by fixing the inorganic fine powder on the surface obtained by simultaneously applying heat to the toner, and fixing the toner with a dry heat roller. It is a manufacturing method of.

The toner of the present invention precipitates (bleeds out) the low molecular weight polypropylene near the particle surface by applying heat to the particles containing the low molecular weight polypropylene in the binder resin. Side effects such as deterioration of fluidity and cohesion caused by addition of low-molecular-weight polypropylene may be minimized.

Further, since the bleed-out has already been performed once, the bleed-out does not occur again due to the heat generated by the agitation or collision in the developing device. Therefore, the spent is not increased by the polypropylene. Moreover, since the toner particles become spherical by the heat treatment, the fluidity and
Cohesiveness is improved.

In addition, the adhesion of particles to each other due to surface melting during production is significantly improved by mixing the hard inorganic fine powder. The manufacturing conditions when the hard inorganic fine powder was not included had a fairly narrow range of appropriate conditions, but the mixing of the hard inorganic fine powder greatly expanded the range of appropriate manufacturing conditions, further improving the fluidity and cohesion of the toner. Was done.

The charging characteristics of the toner can be improved by adding a hard inorganic fine powder having the same composition as the fixed hard inorganic fine powder according to another embodiment of the present invention. That is, since the carrier surface and the toner surface are coated with the same composition, the chargeability does not change. The hard inorganic fine powder fixed to the toner surface and the hard inorganic fine powder to be added later may have the same main component composition, and may have different shapes, particle sizes, and the like.

As the binder resin used in the present invention, for example, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-
Propylene copolymer, styrene-butadiene copolymer,
Styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene
Acrylic ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer,
Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc., styrene-methacrylic ester copolymer (styrene-methyl methacrylate copolymer, styrene-methacrylic) Styrene such as ethyl acrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer), styrene-α-methyl methyl acrylate copolymer, styrene-acrylonitrile-acrylate copolymer Series resin (monoweight or copolymer containing styrene or styrene substituent), vinyl chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, Low molecular weight polypropylene, Iono Chromatography resins, polyurethane resins, silicone resins, ketone resins, ethylene - ethyl acrylate copolymer, xylene resin, there are polyvinyl butyral resins, these resins are not limited to single use, it can be used alone or in combination.

In addition, the production method is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used.

The molecular weight of the low molecular weight polypropylene used in the present invention is a number average molecular weight of 20,000 or less, preferably 1,500 to 10,000.
Is used.

The amount of the low molecular weight polypropylene to be added to the binder resin is 1 to 50 parts by weight, preferably 3 to 15 parts by weight.

Various colorants can be used in the toner of the present invention as needed. Specifically, carbon black, nigrosine dye, aniline blue, ultramarine blue, phthalocyanine blue, chrome yellow, malachite green, rose bengal, or the like can be used alone or in combination. The amount of the colorant is 1 to 30 parts by weight based on 100 parts by weight of the resin component.
Parts by weight, preferably 5 to 15 parts by weight.

In addition, magnetic substances such as ferric oxide and ferrite powder can also be added. The toner matrix of the present invention can be obtained by a known method. For example, a binder resin, a low molecular weight polypropylene, a colorant, and the like are well mixed, and then kneaded with a pressure kneader, a heated double roll, or the like. Thereafter, the mixture is solidified by cooling, pulverized, and classified to obtain base particles of the toner used in the present invention. The toner of the present invention can be obtained by bleeding out the low molecular weight polypropylene by placing the base particles in a closed container, frictional heating by high-speed rotation or heating, instantaneous contact with a high-temperature airflow, or the like.

In another embodiment of the present invention, when heating the toner,
In order to prevent the particles from adhering to each other due to the surface melting of the particles, a hard inorganic fine powder can be further used for the above base particles to fix the fine powder on the particle surface.

As such a hard inorganic fine powder, a known material widely used conventionally can be used. Examples include silicon oxide, titanium oxide, silicon carbide, barium titanate, aluminum oxide, silicon nitride and the like.

The amount of the hard inorganic fine powder added to the base particles is 0.1 to 10.0 parts by weight, preferably 100 parts by weight of the base particles, preferably
0.3 to 3.0 parts by weight.

In addition, the above-mentioned fixation described in the present invention refers to a state in which small-sized particles (hard inorganic fine powder) are adhered to large-sized particles (base particles) with a relatively strong physical force. It does not matter whether the particles are buried in the large particles or not.

Further, the present invention also relates to a toner obtained by further adding 0.1 to 5.0 parts by weight of hard inorganic fine powder having the same composition as the above-mentioned hard inorganic fine powder to the particles having the surface thereof fixed to the base particles for 100 parts by weight of the base particles. Included as an embodiment. In this case, the charge amount can be stabilized, among other aspects of the present invention.

Example 1 Polystyrene (D-125: manufactured by Esso Petrochemical) 90.0 parts by weight Polypropylene (number average molecular weight 3,500) 3.0 parts by weight Carbon black (# 44: manufactured by Mitsubishi Kasei) 7.0 parts by weight Using a heated two-roller with the above formula. Kneading was performed to obtain a base toner having a volume average particle diameter of 10 μm.

200 g of the base toner is placed in a sealed container having a diameter of 50 cm and a rotating blade installed therein. The rotation speed of the rotating blade is 5000r.p.
m. The temperature of the container was kept at 40 ° C., and after operation for 5 minutes, the toner of the present invention was obtained.

Comparative Example 1 The parent toner prepared in Example 1 was used as a comparative example for comparison.

Using the above toner, an unfixed image was created with FT4420 (copier made by Ricoh). At this time, the toner adhesion amount is 1.
It was controlled to be 0 mg / cm ² .

The unfixed image was evaluated for hot offset performance using the apparatus shown in FIG.

The temperature at which hot offset occurs is obtained by gradually increasing the temperature of the Teflon roller (the higher the temperature at which hot offset occurs, the better).

The fluidity index (repose angle, compression degree, spatula angle, cohesion degree) was measured using a powder tester (manufactured by Hosokawa Micron) to examine fluidity and cohesion. The larger the fluidity index, the better the fluidity and cohesion.

From the results in the table, it can be seen that the toner of Example 1 is excellent in both hot offset property and fluidity.

Next, 97.0 parts by weight of a spherical iron oxide carrier having an average particle diameter of 100 μm and 3.0 parts by weight of the toner were placed in a 100 ml stainless steel pot, and continuously stirred for 24 hours to conduct a test for spent property.

The spent amount is obtained by blowing off the developer (mixture of toner and carrier) after stirring for 24 hours, expelling the attached toner by electrostatic force, and measuring the weight (W ₁ ). Next, the fused material is dissolved in toluene and the weight is measured (W ₂ ).

 The spent amount is calculated by the following equation.

From the above results, it can be seen that the toner of Example 1 is excellent in spent property.

Example 2 Styrene-n-butyl methacrylate copolymer 82.0 parts by weight Polypropylene (number average molecular weight 12,000) 7.0 parts by weight Metal complex salt dye 1.0 part by weight Carbon black (# 44) 10.0 parts by weight Same as Example 1 with the above formulation A mother toner having a volume average particle size of 10 μm was obtained.

200 g of the base toner was heat-treated in the same manner as in Example 1. However, the rotation speed of the rotating blades was 5500 rpm, the temperature of the container was 50 ° C., and the toner of the present invention was obtained.

Comparative Example 2 For comparison, the parent toner prepared in Example 2 was used as a comparative example.

Using the toner described above, the hot offset occurrence temperature, the fluidity index, and the spent amount were determined in the same manner as in Example 1.

The results in the table show that the toner of Example 2 is excellent in hot offset property, fluidity, and spent property.

Example 3 Unsaturated polyester 90.0 parts by weight Polypropylene (number-average molecular weight 5,300) 5.0 parts by weight Lionol Blue FG-7351 (manufactured by Toyo Ink) 5.0 parts by weight A base having a volume average particle size of 10 μm in the same manner as in Example 1 with the above formulation. A toner was obtained.

200 g of the base toner was heat-treated in the same manner as in Example 1. However, the rotation speed of the rotating blades was 4000 rpm, the temperature of the container was 35 ° C., and the toner of the present invention was obtained.

Comparative Example 3 For comparison, the parent toner prepared in Example 3 was used as a comparative example.

The hot offset occurrence temperature, the fluidity index, and the spent amount were determined in the same manner as in Example 1 using the above toner.

From the results in the table, it can be seen that the toner of Example 3 is excellent in hot offset property, fluidity, and spent property.

Example 5 Polystyrene (D-125: manufactured by Esso Petrochemical) 90.0 parts by weight Polypropylene (number average molecular weight 3,500) 3.0 parts by weight Carbon black (# 44: manufactured by Mitsubishi Kasei) 7.0 parts by weight Using a heated two roller with the above formula. Kneading was performed to obtain a base toner having a volume average particle size of 10 μm.

A mixture of 200 g of the base toner and 2.0 g of silicon oxide (R972: manufactured by Nippon Aerosil Co., Ltd.) in a mixer is placed in a closed container having a diameter of 50 cm and a rotating blade installed inside.
After rotating the rotating blades at 5,500 rpm for 5 minutes while maintaining the temperature of the container at 45 ° C., the toner of the present invention was obtained.

Example 6 and Comparative Examples 5 and 6 In order to explain the effect of fixing the hard inorganic fine powder shown in Example 5 above, Example 6 and Comparative Examples 5 and 6 will be described below in comparison with Example 5 above. . That is, the base toner prepared in Example 5 (Comparative Example 5), the one obtained by simply mixing the base toner and silicon oxide with a mixer (Comparative Example 6), and the one subjected to heat treatment without adding silicon oxide (Example 6). Was evaluated in the same manner as in Example 1.

From the results shown in the table, it can be seen that the toner of Example 5 has excellent hot offset properties and fluidity. In addition, the spent properties were as shown in the table.

The results in the table show that the toner of Example 5 is excellent in spent property.

Example 7 Styrene-n-butyl methacrylate copolymer 82.0 parts by weight Polypropylene (number average molecular weight 12,000) 7.0 parts by weight Metal complex salt dye 1.0 part by weight Carbon black (# 44) 10.0 parts by weight Same as Example 5 with the above formulation A mother toner having a volume average particle size of 10 μ was obtained.

A mixture of 200 g of the base toner and 2.4 g of titanium oxide (P-25: manufactured by Nippon Aerosil Co., Ltd.) was mixed and heat-treated in the same manner as in Example 1. However, the rotation speed of the rotating blades was 6000 rpm, the temperature of the container was 55 ° C., and the toner of the present invention was obtained.

Example 8 and Comparative Examples 7 and 8 In order to explain the effect of fixing the hard inorganic fine powder on the surface of the toner particles, Example 8 will be described below in comparison with Example 6 described above.
And Comparative Examples 7 and 8. That is, the base toner prepared in Example 7 (Comparative Example 7), the one obtained by simply mixing the base toner and titanium oxide with a mixer (Comparative Example 8), and the one subjected to heat treatment without adding titanium oxide (Example 8). As for Example 5, the hot offset occurrence temperature, the fluidity index and the spent amount were determined in the same manner as in Example 5.

From the results shown in the table, it can be seen that the toner of Example 7 is particularly excellent in hot offset property, fluidity and spent property.

Example 9 Unsaturated polyester 90.0 parts by weight Polypropylene (number-average molecular weight 5,300) 5.0 parts by weight Lionol Blue FG-7351 (manufactured by Toyo Ink) 5.0 parts by weight Base toner having a volume average particle diameter of 10 μm in the same manner as in the above example. I got

A mixture of 200 g of the base toner and 3.0 g of aluminum oxide (Mechanox UB-10: manufactured by Uemura Kogyo Co., Ltd.) was mixed and heat-treated in the same manner as in Example 1. However,
The rotation speed of the rotating blades is 4500 rpm.
The toner of the present invention was obtained.

Example 10 and Comparative Examples 9 and 10 Examples 10 and Comparative Examples 9 and 10 will be described below in comparison with Example 9 in order to explain the effect of fixing the hard inorganic fine powder on the toner particle surface. That is, the base toner prepared in Example 9 (Comparative Example 9), the base toner simply mixed with the aluminum oxide by a mixer (Comparative Example 1)
0) and the heat-treated without aluminum oxide (Example 10), the hot offset occurrence temperature, the fluidity index, and the spent amount were determined in the same manner as in Example 5.

The results in the table show that the toner of Example 9 is particularly excellent in hot offset property, fluidity, and spent property.

Example 11 Polystyrene (D-125: manufactured by Esso Petrochemical) 85 parts by weight Polypropylene (number average molecular weight 3,500) 5 parts by weight Carbon black (# 44: manufactured by Mitsubishi Chemical) 10 parts by weight Kneading,
Base particles having a volume average particle size of 10 μ were obtained.

A mixture obtained by mixing 200 g of the base particles and 2.0 g of silicon oxide (R-972: manufactured by Nippon Aerosil Co., Ltd.) with a mixer has a diameter of
50 cm, put in a sealed container with rotating blades installed inside.

With the number of rotations of the rotating blades kept at 5,000 rpm and the temperature of the container kept at 40 ° C., the mother toner was obtained after running for 5 minutes.

150 g of this base toner and 0.3 g of R-972 were mixed with a mixer to obtain the toner of the present invention.

Next, in order to show that the embodiment of the present invention shown in the above-mentioned Example 11 is particularly excellent, Examples 12 and 13 and Comparative Examples 11 and 12 will be described below in comparison with Example 11. That is, Example 11
Only the base particles prepared in (Comparative Example 11), the base particles and R-
972 simply mixed with a mixer (Comparative Example 12) and R
Heat-treated without adding -972 (Example 12) and R-972
Was evaluated for hot offset occurrence temperature, fluidity index, and spent property in the same manner as in Example 5. The charging stability was evaluated as follows.

Create a developer (97 parts by weight of spherical iron oxide with an average particle diameter of 100 μm and 3 parts by weight of toner) and copy 100,000 times with an experimental machine (charge, exposure, development, transfer, and static elimination 30 times per minute) The charge amount at the start of 10,000, 20,000, 30,000, 50,000 and 100,000 hours was determined by a blow-off method. It can be said that the more this value is constant, the more stable it is against mechanical conditions and environment.

 The evaluation results of each characteristic are shown below.

Hot offset occurrence temperature, fluidity index, spent property The above results show that the toner of Example 11 is particularly excellent in hot offset property, fluidity, spent property, and charging stability.

Example 14 80 parts by weight of styrene-n-butyl methacrylate copolymer 10 parts by weight of polypropylene (number average molecular weight 12,000) 2 parts by weight of metal complex salt dye 8 parts by weight of carbon black (# 44) 8 parts by weight Kneading was performed to obtain base particles having a volume average particle size of 10 μm.

Example 11 was obtained by mixing 200 g of the base particles and 2.4 g of titanium oxide (P-25: manufactured by Nippon Aerosil Co., Ltd.) with a mixer.
The heat treatment was performed in the same manner as described above. However, a mother toner was obtained in which the number of rotations of the rotating blades was 6000 rpm and the temperature of the container was 55 ° C.

150 g of this base toner and 0.75 g of P-25 were mixed with a mixer to obtain the toner of the present invention.

In order to explain that the embodiment shown in Example 14 is particularly excellent, Examples 15 and 16 and Comparative Examples 13 and 14 will be described below in comparison with Example 14. That is, only the base particles prepared in Example 14 (Comparative Example 13), those obtained by simply mixing the base particles and P-25 with a mixer (Comparative Example 14), and those obtained by heat treatment without adding P-25 (Example) 15) and those without post-addition of P-25 (Example 16) were evaluated in the same manner as in Example 11.

Hot offset occurrence temperature, fluidity index, spent property From the above results, it can be seen that the toner of Example 14 is particularly excellent in hot offset property, fluidity, spent property, and charging stability.

Example 17 85 parts by weight of unsaturated polyester 10 parts by weight of polypropylene (number average molecular weight 5,300) 5 parts by weight of Lionol Blue FG-7351 (manufactured by Toyo Ink) 5 parts by weight Base particles having a diameter of 10 μ were obtained.

200 g of the base particles and aluminum oxide (Mechanox
UB-10: manufactured by Uemura Kogyo Co., Ltd.) and heat-treated in the same manner as in Example 1. However, the rotation speed of the rotating blades is 4000 rpm, and the temperature of the container is 35 ° C.
A mother toner was obtained.

150 g of this base toner and 3.0 g of UB-10 were mixed with a mixer to obtain the toner of the present invention.

Examples 18 and 19 and Comparative Examples 15 and 16 will be described below in comparison with Example 17 in order to explain that the mode shown in Example 17 is particularly excellent. That is, only the base particles prepared in Example 17 (Comparative Example 15), those obtained by mixing base particles UB-10 with a mixer (Comparative Example 16), and those heat-treated without adding UB-10 (Example) 18) and those without post-addition of UB-10 (Example 19) were also evaluated in the same manner as in Example 1.

Hot offset occurrence temperature, fluidity index, spent property From the above results, it can be seen that the toner of Example 17 is particularly excellent in hot offset property, fluidity, spent property, and charging stability.

[Effects of the Invention] As described above, fluidity, cohesiveness,
Hot offset can be prevented without impairing various characteristics such as the spent property with respect to the carrier, and a toner for dry heat roller fixing having improved heat fixability can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an apparatus for evaluating hot offset performance.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasutaka Iwamoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company Limited (72) Inventor Takahisa Kato 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-59-231547 (JP, A) JP-A-63-85756 (JP, A) JP-A-2-87159 (JP, A)

Claims (6)

(57) [Claims] Claims: 1. A toner comprising at least a binder resin and low molecular weight polypropylene, which is heated or subjected to frictional heat or both heats at the same time to deposit low molecular weight polypropylene near the surface of the particles. A non-magnetic toner for fixing a dry heat roller, wherein an offset generation temperature is 210 ° C. to 250 ° C. 2. A method for producing a toner for fixing with a heat roller, comprising mixing at least a binder resin and a low molecular weight polypropylene, and then applying heating, frictional heat or both heats simultaneously to the obtained particles. A method for producing a non-magnetic toner for fixing a dry heat roller, wherein the temperature of the heat is 35 ° C. to 55 ° C. (3) heating, frictional heat or both heats are simultaneously applied to particles obtained by mixing at least a binder resin, particles composed of low molecular weight polypropylene and hard inorganic fine powder having a smaller particle size than the particles; A toner comprising a low-molecular-weight polypropylene deposited near the particle surface and a hard inorganic fine powder fixed on the surface, wherein a hot offset occurrence temperature is 215 ° C. to 245 ° C. Magnetic toner. 4. A method for producing a toner for fixing with a heat roller, wherein at least a binder resin and a low molecular weight polypropylene are mixed, and then the obtained particles are mixed with a hard inorganic fine powder having a smaller particle size than the particles. A method for producing a toner, which comprises applying heating, frictional heat or both heats simultaneously to the mixed particles, wherein the temperature of the heat is 35 ° C. to 55 ° C. A method for producing a non-magnetic toner. 5. A method in which heating, frictional heat or both heats are simultaneously applied to particles obtained by mixing at least a binder resin and particles composed of a low molecular weight polypropylene and a hard inorganic fine powder having a smaller particle size than the particles. Precipitating low molecular weight polypropylene near the surface of the particles, and further mixing the hard inorganic fine powder having the same composition as the fixed hard inorganic fine powder with the particles obtained by fixing the hard inorganic fine powder on the surface. Dry heat roller fixing toner. 6. A method for producing a toner for fixing with a heat roller, wherein at least a binder resin and a low molecular weight polypropylene are mixed, and then the obtained particles are mixed with a hard inorganic fine powder having a smaller particle size than the particles. Further, a hard inorganic fine powder having the same composition as the inorganic fine powder is mixed with particles obtained by fixing the inorganic fine powder to the surface by heating, frictional heat or both heats applied simultaneously to the mixed particles. A method for producing a toner for fixing with a dry heat roller.