JP2002148845A - Image forming method and toner for image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method by which an excellent fixing property is maintained, whose off-setting resistant property is excellent and also by which the soiling of a pressure roller is not caused. SOLUTION: In the image forming method having a fixing process to thermally pressure and fix a toner image T to a transfer material P by holding and feeding the transfer material having the toner image formed of toner between a heating member 703 having heat-resistant film 702 rotated and moved and a pressure member 706, the toner has toner particles incorporating at least a binding resin, a colorant and wax and an additive, and has a component which has at least the maximum value of a DSC endothermic curve in the range of the temperature of 105 deg.-150 deg.C, and has the main peak of the GPC of the THF soluble component of the toner in the range of the molecular weight of 20,000-25,000, and has a subpeak or a shoulder in the range of the molecular weight of >=700,000, and whose Mw/Mn is >=8 and whose molecular weight is in the range of 1,000-100,000 for 20-70%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method having a fixing step of heating and pressing a toner image on a transfer material in electrophotographic technology, and a toner used in the image forming method.

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat.
A number of devices are known as described in Japanese Patent Publication No. 7,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748. Generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is developed using a toner. If necessary, a transfer material such as paper (recording material) is used. ), The toner image is transferred, and then fixed by heating, pressure, heating and pressurizing, or solvent vapor to obtain a copy or print. Further, the remaining toner that has not been transferred onto the photosensitive member is cleaned by various devices, and the above steps are repeated.

In recent years, such copying apparatuses have begun to be used not only as office work copying machines for copying original manuscripts but also for copying high-definition images such as printers and graphic designs as computer outputs. .

As for printer devices, LED and LBP printers have become the mainstream in the recent market, and higher resolutions, that is, those which have conventionally been 240, 300 dpi, have become 600,
800 and 1200 dpi. Accordingly, the development system is required to have higher definition. Also, the functions of copiers are becoming more sophisticated,
Therefore, it is moving toward digitalization. In this direction, a method of forming a toner-visible image by a laser is mainly used, so that the direction is also proceeding to a higher resolution, and a high-resolution and high-definition developing method is required similarly to a printer. . JP-A-1-112253 and JP-A-2-112253
Japanese Patent Application No. 284158 discloses a toner having a small particle diameter. For this reason, higher reliability has been strictly pursued, and the required performance has become higher accordingly. Unless the performance of the image forming apparatus including the toner can be improved, a better machine cannot be realized. ing.

A device for fixing a visible image of toner on a recording material includes a heating roller maintained at a predetermined temperature,
A heat roller fixing method in which a recording material holding an unfixed toner visible image is heated while being nipped and conveyed by a pressure roller having an elastic layer and pressed against the heat roller is often used. Further, a belt fixing system described in U.S. Pat. No. 3,578,797 is known.

However, in the above-described conventional heat roller fixing method, there are (1) a time period during which the image forming operation is prohibited until the heat roller reaches a predetermined temperature, that is, a so-called wait time; It is necessary to maintain the heating roller at the optimum temperature in order to prevent defective fixing due to the fluctuation of the temperature of the heating roller due to other external factors and the offset phenomenon in which the developer is transferred to the heating roller. (3) Since the heat capacity of the heating roller or the heating element needs to be increased, a large amount of electric power is required; (3) Since the temperature of the roller is high, when the recording material is discharged through the heating roller, the recording is performed. Because the developer on the recording material and the recording material is cooled slowly, the adhesiveness of the developer becomes high,
Depending on the curvature of the heating roller, a paper jam may occur due to offset or entanglement of the recording material. (4) A protective member may be required because the high-temperature heating roller does not directly touch the hand. There are issues.

Also, in the belt fixing method described in US Pat. No. 3,578,797, the above-mentioned problems (1) and (2) of the heat roller fixing have not been fundamentally solved.

In Japanese Patent Application Laid-Open No. 63-313822, a wait time for heating a toner visible image via a moving heat-resistant sheet by means of a low-heat-capacity heating element heated in a pulsed manner and fixing it on a recording material. A fixing device with a short power consumption and low power consumption has been proposed.

In the heating method using a film, fixing is performed by passing a toner image surface of a sheet to be fixed onto a heat roller or a surface of a film formed of a material having a releasable property with respect to the toner, while contacting the toner image surface. It is what you do. In this method, since the surface of the heat roller or the film comes into contact with the toner image of the sheet to be fixed, the thermal efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. Yes, it is effective in electrophotographic copying machines.

However, in the above method, since the film surface and the toner image come into contact in a molten state, a part of the toner image adheres and transfers to the film surface and re-transfers to the next sheet to be fixed, thereby causing an offset phenomenon. And the sheet to be fixed may be stained. It is important in the heat fixing method to prevent the toner from adhering to the film surface.

In recent years, the use of recycled paper has been increasing year by year from the viewpoint of environmental problems and resource protection. Among these recycled papers, a large amount of additives such as calcium carbonate are used for the purpose of improving the whiteness of the paper. There are those contained in. When these papers are used, there is a problem that the additive and toner separated from the paper accumulate on the pressing member of the image forming method and appear as image stains (hereinafter referred to as "pressure roller stains"). Have been doing. It is desired to prevent the above-mentioned image stains, due to the downsizing and power saving of the fixing device for achieving the downsizing of the printer device and the speeding up of the printer device.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method and a toner for an image forming method which achieve good fixability, have excellent offset resistance, and do not cause contamination of a pressure roller. To provide.

[0013]

According to the present invention, a transfer material having a toner image formed of toner is nipped and conveyed between a heating member having a heat-resistant film which rotates and a pressing member. In a method for forming an image having a fixing step of heating and pressing a toner image onto a transfer material by heating, the pressing member has a heat-resistant elastic layer having a thermal conductivity of 0.20 W / m · K or less on a cored bar. And the fixing speed is 55 mm /
sec or more, and the power consumption of the heating member is 0.4
0 to 0.70 Wh / sheet, the toner has toner particles containing at least a binder resin, a colorant and a wax, and an external additive. The toner has a temperature of 105 to 150 ° C. in a DSC endothermic curve. In the GPC of the THF soluble component of the toner,
It has a main peak in the molecular weight region of 2,000 to 25,000, a subpeak or a shoulder in the molecular weight region of 70,000 or more, Mw / Mn of 8 or more, and a molecular weight of 10 or more.
The present invention relates to an image forming method having 20 to 70% of components in a region of 00 to 10000.

Further, the present invention provides a transfer material having a toner image formed of toner between a heating member having a heat-resistant film which rotates and a pressing member, and conveys the toner image onto the transfer material. The fixing member has a fixing step of heating and pressing, and the pressing member has a heat conductivity of 0.20 W / m · K on a cored bar.
An image forming method which has a heat-resistant elastic layer as follows, has a fixing speed of 55 mm / sec or more, and has a power consumption of 0.40 to 0.70 Wh / sheet for a pressing member. In the method toner, the toner has toner particles containing at least a binder resin, a colorant and a wax, and an external additive.
C has at least a maximum value in a temperature range of 105 ° C. to 150 ° C. in an endothermic curve,
PC has a main peak in a molecular weight region of 2,000 to 25,000, a subpeak or a shoulder in a molecular weight region of 70,000 or more, and a component having a Mw / Mn of 8 or more and a molecular weight of 1,000 to 10,000 in two regions.
The present invention relates to a toner for an image forming method, comprising 0 to 70%.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention, which satisfies the above-mentioned constitutional requirements, enables fixing with little power consumption in a copying machine having a certain process speed, no occurrence of offset, and further occurrence of contamination of a pressure roller. It is possible to obtain an image having no image. Fixing / offset has a close relationship with the molecular weight distribution of the toner composed of the polymer resin in GPC. The low molecular weight component has an effect on the low-temperature fixability, and the high molecular weight component has an effect on the offset resistance. Pressure roller dirt has a close relationship with the endothermic temperature of the DSC curve of the toner, and effectively prevents pressure roller dirt when the endothermic peak temperature is in a temperature region equivalent to the surface temperature region of the pressure roller. It becomes possible.

The toner used in the present invention will be described.

The toner suitably used in the present invention has toner particles containing at least a binder resin, a colorant and a wax, and an external additive. The toner has a temperature of 105 to 150 ° C. in a DSC endothermic curve. In the GPC of the THF-soluble component of the toner, the toner has a main peak in a molecular weight region of 2,000 to 25,000, a subpeak or a shoulder in a molecular weight region of 70,000 or more, and a Mw / Mn of 8 And the components in the molecular weight region of 1,000 to 10,000 are 20 to 70.
%.

The DSC heat absorption curve is closely correlated with the fixing property, the anti-offset property, and the contamination of the pressure roller, and the fixing method of the present invention is preferably used in the case of having the above thermal characteristics. When there is a peak only in a region smaller than 105 ° C., the occurrence of offset and dirt on the pressure roller becomes undesirably apparent. When it has a peak only in a region higher than 150 ° C., the low-temperature fixability is not achieved, which is not preferable.

The molecular weight distribution obtained by GPC of the THF-soluble component of the toner and the basic development characteristics are of course, but the interrelationship between the fixing property, the offset resistance and the contamination of the pressure roller is particularly close. . If the main peak is smaller than 2,000, the developability deteriorates and it becomes difficult to obtain a normal image density. If it is larger than 25,000, it is difficult to secure good fixing properties. Molecular weight 7000
When there is no sub-peak or shoulder in a region of 0 or more, good offset resistance and the effect of preventing the pressure roller from being stained tend to be reduced. If Mw / Mn is smaller than 8, it is difficult to ensure good offset properties.
20% of components in the molecular weight range of 1,000 to 10,000
If the amount is less, it is difficult to secure good fixing properties. If it is more than 70%, the developability during durability tends to decrease, which is not preferable.

Further, it is more preferable that the toner of the present invention has a maximum value even in a temperature range of 60 to 100 ° C. in a DSC endothermic curve, so that the object of the present invention can be satisfactorily achieved.

In the above-mentioned DSC curve, the phase between the toner and the wax contained in the toner is large. Further, the molecular weight distribution has a large correlation with the binder resin. The wax used in the present invention will be described.

The waxes contained in the toner of the present invention include the following. For example, low molecular weight polyethylene,
Aliphatic hydrocarbon waxes such as low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxides of aliphatic hydrocarbon waxes such as polyethylene oxide wax;
Or block copolymers thereof; vegetable waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax; animal waxes such as beeswax, lanolin, and spermaceti; mineral based waxes such as ozokerite, ceresin, petrolatum. Wax; waxes mainly containing fatty acid esters such as montanic acid ester wax and caster wax; and those obtained by partially or entirely deoxidizing fatty acid esters such as deoxidized carnauba wax. Further, unsaturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a longer-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and barinaric acid; stearyl alcohol; Eicosyl alcohol, behenyl alcohol,
Saturated alcohols such as carnaubavir alcohol, seryl alcohol, melisyl alcohol, or long-chain alkyl alcohol having a longer-chain alkyl group; polyhydric alcohols such as sorbitol; linoleamide, oleic amide, lauric amide Aliphatic amides; saturated fatty acid bisamides such as methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide; ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, N, N Unsaturated fatty acid amides such as' -dioleyl adipamide, N, N'-dioleyl sebacamide; aromatic bisamides such as m-xylene bis stearamide, N, N'-distearyl isophthalic amide ; Fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate (commonly referred to as metal soaps); grafted onto aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid Waxes; partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols; and methyl ester compounds having a hydroxyl group obtained by hydrogenating vegetable oils and fats.

The wax preferably used is a polyolefin obtained by radical polymerization of an olefin under high pressure;
A polyolefin obtained by purifying a low-molecular-weight by-product obtained during polymerization of a high-molecular-weight polyolefin; a polyolefin polymerized under a low pressure using a catalyst such as a Ziegler catalyst or a metallocene catalyst; a polyolefin polymerized by using radiation, electromagnetic waves or light; Low molecular weight polyolefin obtained by pyrolyzing polyolefin; paraffin wax,
Microcrystalline wax, Fischer-Tropsch wax; Synthetic hydrocarbon wax synthesized by the Jindole method, Hydrocoll method, Age method, etc .; Synthetic wax using a compound having 1 carbon atom as a monomer, having a functional group such as a hydroxyl group or a carboxyl group Hydrocarbon wax; a mixture of a hydrocarbon wax and a wax having a functional group; and a wax obtained by graft-modifying a vinyl monomer such as styrene, maleic ester, acrylate, methacrylate, or maleic anhydride using these waxes as a base. .

The melting point of the wax used in the present invention is 10
It is preferably 5 to 155 ° C. (maximum endothermic peak). The temperature is more preferably 110 to 150 ° C.
The surface temperature of the pressure roller of the present invention is 110 to 160 ° C., more preferably 110 to 150 ° C., and within this range, 60 to 9 to further achieve the object of the present invention.
Melting point 60-9 having an endothermic main peak in the region of 5 ° C
More preferably, the wax further contains 5 ° C wax. Therefore, the toner has a DSC endothermic peak in the range of 60 to 90 ° C., and further has a DS endothermic peak in the range of 110 to 150 ° C.
It preferably has an endothermic peak of C.

The content of the wax in the toner used in the present invention is 0.5 to 3 with respect to 100 parts by mass of the binder resin.
It is preferably 0 parts by mass, more preferably 2 to 10 parts by mass.

The melting point of the wax was determined by using a DSC-7 (manufactured by PerkinElmer) at a heating rate of 10 ° C./min.
It is measured according to the temperature measurement pattern of TM D3418, and is defined as the peak top value of the highest melting temperature.

Next, the binder resin used in the present invention will be described.

As the binder resin, polystyrene;
Styrene-substituted homopolymers such as p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer Styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin and petroleum resin. Further, a crosslinked styrene resin is also a preferable binder resin.

As comonomers for the styrene monomer of the styrene copolymer, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, Monocarboxylic acid having a double bond such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; maleic acid,
Dicarboxylic acids having a double bond such as butyl maleate, methyl maleate and dimethyl maleate and their substituted products; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; ethylene olefins such as ethylene, propylene and butylene And vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; and vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. These vinyl monomers are used alone or in combination.
As the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used. Specifically, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline And divinyl compounds such as divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups. These can be used alone or as a mixture.

Further, the gel chromatogram (GP) of the soluble component of tetrahydrofuran (THF) of the toner of the present invention
The correlation between C) and GPC of the binder resin is high. The toner suitably used in the present invention has at least one peak in a region of a molecular weight of 3,000 to 30,000, preferably in a region of a molecular weight of 3,000 to 25,000, and a molecular weight of 100 It is preferable to have at least one peak or shoulder in the region of 2,000 or more. When the toner has such a peak in the molecular weight distribution, the fixing property, the anti-offset property, and the storability can be maintained in a well-balanced state, and the toner can have durability and uniform chargeability.

The peak molecular weight of the high molecular weight component is 100,0
If it is less than 00, the high-temperature offset resistance of the toner decreases, the dispersibility of the wax component decreases, the dispersion state becomes insufficient, and image defects such as a decrease in image density tend to occur.
When the peak molecular weight of the low molecular weight component is less than 3,000, plasticization by the wax component is likely to proceed,
Since the phase separation easily occurs locally, the frictional charge of the toner becomes non-uniform, and the developing characteristics may be deteriorated. On the other hand, when the peak molecular weight of the low molecular weight component exceeds 25,000, the dispersion state of the wax component is improved to some extent,
Although the developing characteristics are improved, the fixability is reduced.

In order to impart the above-mentioned molecular weight distribution to the toner, the binder resin component used in the present invention has a molecular weight distribution of 2,000 to 25,000 in a molecular weight distribution measured by GPC of a THF-soluble component. A low molecular weight polymer having at least one peak in a region, and a molecular weight of 100,000
It is preferable to be composed of a high molecular weight polymer having at least one peak or shoulder in the region of 1,000,000.

These binder resin components can be mixed and dispersed in advance with a wax component before producing the toner. In particular, a method in which the wax component and the high molecular weight polymer are preliminarily dissolved in a solvent during the production of the binder, and then mixed with the low molecular weight polymer solution is preferable. By mixing the wax component and the high molecular weight component in advance, the phase separation in the micro region is reduced, the high molecular weight component is not re-aggregated, and a good dispersion state with the low molecular weight component can be obtained.

In the present invention, the toner or the binder resin
The molecular weight distribution by GPC using THF as a solvent is measured under the following conditions.

The column was stabilized in a heat chamber at 40 ° C., and THF was added to the column at this temperature as a solvent.
At a flow rate of 1 ml / min.
Measure by injecting 0 μl. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, Tosoh Corporation or Showa Denko KK having a molecular weight of about 10 ² to 10 ⁷ is used, and it is appropriate to use a standard polystyrene sample of at least about 10 points. . An RI (refractive index) detector is used as the detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, Shodex GPC KF-801, 802, 80 manufactured by Showa Denko KK
3,804,805,806,807,800P or TSKgelG1000H (H
_{XL), G2000H (H XL)} , G3000H (H XL),
_{G4000H (H XL), G5000H (} H XL), G60
00H (H _XL ), G7000H (H _XL ), TSKgua
rdcolumn can be mentioned.

The sample is prepared as follows.

After placing the sample in THF and leaving it for several hours,
Shake well and mix well with THF (until the sample is no longer united) and let sit for at least 12 hours. At this time, THF
The time for which the sample is left inside is set to 24 hours or more. Thereafter, the sample processing filter (pore size 0.
45 to 0.5 μm, for example, Mysholidisk H-25
-5 (manufactured by Tosoh Corporation, Exiclodisc 25CR manufactured by Germanic Science Japan) can be used as a GPC measurement sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

A charge control agent can be used in the toner, if necessary, to further stabilize the chargeability. The charge controlling agent is 0.1 to 100 parts by mass of the binder resin.
It is preferred to use 10 parts by weight, preferably 1 to 5 parts by weight.

As the toner suitably used in the present invention,
There is a magnetic toner containing a magnetic substance. Examples of the magnetic substance used include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. Among them, those mainly containing iron oxide such as triiron tetroxide and γ-iron oxide are preferable. Further, from the viewpoint of improving the fluidity of the toner and controlling the chargeability, it is preferable that the magnetic substance contains a silicon atom. In particular, when the toner particles have a small diameter, the fluidity of the toner particle base is reduced. Therefore, only by externally adding an external additive such as an inorganic fine powder, good fluidity cannot be obtained and good chargeability cannot be obtained. The content of silicon atoms is preferably from 0.2 to 2.0% by mass based on the magnetic material. If the amount is less than 0.2% by mass, fluidity is reduced and character sharpness is reduced. And adverse effects such as low solid black density tend to occur. 2.0
When the content is more than the mass%, the image density tends to decrease particularly in a high temperature and high humidity environment. The content of silicon atoms is more preferably 0.3 to 1.7% by mass. In particular, it is more preferable that silicon atoms are present at 0.05 to 0.5% by mass on the surface of the magnetic material. Pigments or dyes such as carbon black and copper phthalocyanine may be used as a colorant in the toner in addition to the magnetic substance.

The silicon atom may be added in the form of a water-soluble silicon compound when the magnetic substance is formed. After the formation of the magnetic substance, filtration and drying, the silicon atom is added in the form of a silicate compound and fixed to the surface with a mix muller or the like. You may. These magnetic particles preferably have a BET specific surface area measured by a nitrogen adsorption method of 2 to 3 times.
0 m ² / g is good, and especially 3 to 28 m ² / g is good. Further, magnetic particles having a Mohs hardness of 5 to 7 are preferred.

The shape of the magnetic particles includes an octahedron, a hexahedron, a sphere, a needle, and a scale. Those having little anisotropy, such as an octahedron, a hexahedron, and a sphere, are preferable. In particular, it is preferable that the sphericity 磁性 of the magnetic particles be 0.8 or more in order to increase the image density. The average particle size of the magnetic particles is 0.05
To 1.0 μm, more preferably 0.1 to 0.6 μm, and particularly preferably 0.1 to 0.4 μm.

The content of the magnetic substance is from 30 to 200 parts by mass, preferably from 60 to 20 parts by mass, per 100 parts by mass of the binder resin.
0 parts by mass, and more preferably 70 to 150 parts by mass. 30
If the amount is less than the mass part, the transportability is reduced, the magnetic toner layer on the developer carrying member tends to be uneven, and the image tends to be uneven, and the image density tends to be reduced due to the increase in the tribo of the magnetic toner. There is. On the other hand, when the content of the magnetic material is 20
If it exceeds 0 parts by mass, the fixability tends to decrease.

Examples of the charge control agent include the following.

As a negative charge controlling agent for making the toner negatively chargeable, an organic metal complex or a chelate compound is effective.
Examples thereof include a monoazo metal complex, a metal complex of an aromatic hydroxycarboxylic acid, and a metal complex of an aromatic dicarboxylic acid.
Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides or esters thereof, and phenol derivatives of bisphenol.

Examples of the positive charge control agent for making the toner positively chargeable include nigrosine, nigrosine derivatives, triphenylmethane compounds, and organic quaternary ammonium salts.

Further, as a preferable embodiment of the toner used in the present invention, it is possible to appropriately add a fluidity improver or an abrasive.

The fluidity improver has a number average diameter of 0.1.
005 to 0.07 μm. For example, there are fine alumina powder and fine silica powder. Furthermore, these fine powders
Those whose surfaces have been subjected to coupling treatment, oil treatment or treatment with fatty acids are preferred. Particularly preferred is a silicic acid fine powder which has been subjected to an oil treatment after the coupling treatment.

As the abrasive, those having a number average diameter of 0.12 to 3.0 μm can be preferably used. For example, iron oxide, chromium oxide, calcium titanate, strontium titanate, barium titanate, magnesium titanate,
Cerium oxide, zirconium oxide, aluminum oxide,
There are titanium oxide, zinc oxide and calcium oxide. Strontium titanate, cerium oxide and titanium oxide are preferably used.

The content of the fluidity improver is 0.1 to the toner.
The content is preferably 5 to 2.5% by mass, and the content of the abrasive is preferably 0.35 to 3.5% by mass based on the toner.

More preferably, the toner of the present invention has the following circularity.

The particles having a circularity a of 0.900 or more determined by the following formula (A) in the toner particles having a particle size of 3 μm or more have 90% by number or more in terms of the number-based cumulative value, and the circularity a has a value of 0. .950 or more are 6 in terms of number-based cumulative value
Particles having a number of 7% or more and a circularity a of 0.995 or more exist in a number-based cumulative value of 8% or more and a circularity a of 0.995 or more are present in a circular shape. It is more preferable to use a case in which the degree a is 12% by number or more of the cumulative value based on the number of particles of 0.950 or more.

[0052]

(Equation 3) (In the formula, L ₀ indicates the perimeter of a circle having the same projected area as the particle image, and L indicates the perimeter of the particle image.)

When the toner has the above-described shape, it is possible to more effectively prevent the pressure roller from being stained.

When the toner is produced by, for example, mechanical impact, the wax on the particle surface is melted by the grinding action, and the wax on the particle surface covers the magnetic material on the toner particle surface. As a result, the toner having the above-mentioned circularity is closer to a sphere than the toner manufactured by a normal pulverization method, and the wax is appropriately present on the particle surface and the exposure of the magnetic substance is suppressed. . This is because when the magnetic material is exposed on the surface or when the amount of the free magnetic material increases, the toner easily adheres to the surface of the pressure roller.

When producing a toner having a specific circularity, the weight average particle diameter is 5 to 10 μm, particles having a particle diameter of 4 μm or less are 40% by number or less, and particles having a particle diameter of 10.1 μm or more are 25% by volume. % Or less.

To obtain a toner having a weight average diameter of more than 10 μm, the load in the pulverizer is reduced as much as possible, it is difficult to make the toner particles have a desired circularity distribution, and it is difficult to prevent the pressure roller from being stained satisfactorily. It will be difficult.

When a toner having a weight average diameter of less than 5 μm is obtained, the load in the pulverizer is increased in a direction that is not preferable from the viewpoint of production, but the generation of fine powder or ultrafine powder is increased, and drum fusion or fogging or cleaning is performed. Failure is likely to occur.

25% by volume of particles having a particle size of 10.1 μm or more
Is larger than 10 μm
The same harmful effects as in the case of obtaining a toner exceeding the above tend to occur.

In the case where the toner having a particle size of 4.0 μm or less exceeds 40% by number, the same harmful effects as in the case of obtaining the toner having a weight average diameter of less than 5 μm are likely to occur.

The particle size distribution of the toner was measured by the following method.

The particle size distribution can be measured by various methods. In the present invention, the measurement was carried out using a Coulter counter multisizer.

As a measuring apparatus, a Coulter counter Multisizer II or IIE (manufactured by Coulter) was used, and an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution and a general personal computer were connected. As the electrolyte, a 1% NaCl aqueous solution is prepared using a special grade or primary grade sodium chloride. As a measuring method, a surfactant (preferably an alkylbenzene sulfonate) is used as a dispersant in 100 to 150 ml of the electrolytic aqueous solution.
Is added, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample was suspended was treated with an ultrasonic
The dispersion treatment is performed for one minute, and the measurement is performed using a 100 μm aperture with the Multisizer II of the Coulter Counter. The volume and number of the toner are measured, the volume distribution and the number distribution are calculated, and the weight-based weight average diameter determined from the volume distribution is determined.

If the number of particles having a circularity a of 0.900 or more is less than 90% in terms of the number-based cumulative value, contamination of the pressure roller is undesirably deteriorated. The presence of particles having a circularity a of 0.950 or more is 67 based on the number-based cumulative value.
% Is not preferable because contamination of the pressure roller deteriorates. When the number of particles having a circularity a of 0.995 or more is less than 8% in terms of the number-based cumulative value, contamination of the pressure roller is undesirably deteriorated.

Also, when the presence of the particles having the circularity a of 0.995 or more and the abundance ratio of the particles having the circularity a of 0.950 or more are less than 12%, the pressure roller is easily stained. .

As one standard of such a variation of the particles having each circularity, the circularity standard deviation SD can be used. In the present invention, there is no problem if the circularity standard deviation SD is 0.034 to 0.043.

The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of particles. In the present invention, the average circularity is measured using a flow particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics. Is performed, the circularity of the measured particles is obtained by the following equation (A), and the average circularity obtained by dividing the sum of the circularities of all the particles measured by the following equation (B) by the total number of particles is further obtained. Define.

[0067]

(Equation 4) (In the formula, L ₀ indicates the perimeter of a circle having the same projected area as the particle image, and L indicates the perimeter of the particle image.)

[0068]

(Equation 5)

[0069]

[0070]

(Equation 6)

The degree of circularity used in the present invention is an index of the degree of unevenness of the toner particles. The degree of circularity is 1.00 when the toner is perfectly spherical, and the circularity becomes smaller as the surface shape becomes more complicated. In addition, the SD of the circularity distribution in the present invention
Is an index of the variation, and the smaller the numerical value, the smaller the variation of the toner shape.

The measuring device “FP” used in the present invention
IA-1000 "is a class obtained by calculating the circularity of each particle, and then calculating the average circularity and the circularity standard deviation. Each value of the average circularity and circularity standard deviation using the center value and frequency of the division point, and the average circularity and circularity standard deviation calculated by the above-described calculation formula using the circularity of each particle directly Is very small and practically negligible, and in the present invention, for the reasons of data handling such as shortening of calculation time and simplification of calculation formula, each particle described above is Such a calculation method that is partially modified using the concept of a calculation formula that directly uses circularity may be used.

As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersing agent to 100 to 150 ml of water from which impurities have been removed in a container in advance, and the measurement is further performed. 0.1
Add about 0.5 g. The suspension in which the sample is dispersed is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the dispersion concentration is adjusted to 3
Using the above-mentioned flow type particle image measuring apparatus, the particle size is determined to be 6,000 to 10,000 particles / μl, and 0.60 μm to 159.21 μm.
The circularity distribution of particles having a circle equivalent diameter of less than is measured.

The outline of the measurement is described in the catalog of FPIA-1000 (June 1995 edition) issued by Toa Medical Electronics Co., Ltd., the operation manual of the measuring apparatus, and Japanese Patent Application Laid-Open No. 8-136.
No. 439, which is as follows.

The sample dispersion liquid is passed through a flow path (spread along the flow direction) of a flat and flat flow cell (about 200 μm thick). The strobe and the CC are connected so as to form an optical path that intersects with the thickness of the flow cell.
The D cameras are mounted so as to be located on opposite sides of the flow cell. While the sample dispersion is flowing,
Strobe light is applied at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle is captured as a two-dimensional image having a range parallel to the flow cell. The diameter of a circle having the same area is calculated as the equivalent circle diameter from the area of the two-dimensional image of each particle. The circularity of each particle is calculated from the projected area of the two-dimensional image of each particle and the perimeter of the projected image using the above-described circularity calculation formula.

In the method for producing a toner, a binder resin,
A mixture containing at least a magnetic substance and a wax is melt-kneaded, the obtained kneaded product is cooled, and the cooled product is pulverized by a pulverizing means, and a coarsely pulverized product is used as a powder raw material. Then, first, a rotor which is a rotating body having a predetermined amount of the pulverized raw material attached to at least the center rotating shaft, and a stator which is arranged around the rotor while keeping a constant interval from the rotor surface. By introducing into a mechanical crusher that is configured so that an annular space formed by maintaining the distance and having an airtight state, and rotating the rotor of the mechanical crusher at a high speed. Finely pulverize the object. Next, the finely pulverized raw material is introduced into a classification step and classified to obtain a classified product as a toner raw material composed of a group of particles having a specified particle size. At this time, in the classification step, a multi-divided airflow classifier having at least a coarse powder region, a medium powder region, and a fine powder region is preferably used as a classification means. For example, when a three-split airflow classifier is used, the powder raw material is classified into at least three types of fine powder, medium powder, and coarse powder. In the classification process using such a classifier, a coarse powder composed of a group of particles having a larger particle size than the preferred particle size and a fine powder composed of a group of particles having a particle size smaller than the preferred particle size are removed, and the medium powder is used as it is as a toner product. Or used after being mixed with an external additive such as hydrophobic colloidal silica.

The fine powder composed of particles having a particle size smaller than the preferred particle size classified in the above-mentioned classification step is generally subjected to a melt-kneading step for producing a powder raw material composed of the toner material introduced into the pulverization step. To be reused or discarded. Also, ultrafine powder having a smaller particle diameter than the above fine powder and slightly generated in the pulverizing step and the classifying step is similarly supplied to the melt-kneading step and reused or discarded.

The mechanical pulverizer preferably used as the pulverizing means used in the toner production method of the present invention will be described. Examples of the mechanical pulverizer include a pulverizer KTM and Kryptron manufactured by Kawasaki Heavy Industries, Ltd., and a turbo mill manufactured by Turbo Kogyo Co., Ltd. These apparatuses can be used as they are or after being appropriately improved. preferable.

To prepare the toner of the present invention, a mixture containing at least a binder resin, a magnetic substance and a wax is used as a material. In addition, if necessary, a charge control agent, other additives, and the like are used. Used. These materials were thoroughly mixed by a mixer such as a Henschel mixer or a ball mill, and then melted, kneaded and kneaded using a hot kneader such as a roll, kneader and extruder to make the resins compatible with each other. The toner can be obtained by dispersing or dissolving a pigment or dye, cooling and solidifying, and then performing pulverization and classification. In the present invention, the apparatus system having the above-described configuration is used in the pulverization step and the classification step. Is used.

As a mixing machine, a Henschel mixer (manufactured by Mitsui Mining); a super mixer (manufactured by Kawata); a ribocorn (manufactured by Okawara Seisakusho); a Nauta mixer, a turbulizer, a cyclomix (manufactured by Hosokawa Micron); Pin mixers (manufactured by Taiheiyo Kiko Co., Ltd.); Ledige mixers (manufactured by Matsubo), and kneading machines include KRC kneader (manufactured by Kurimoto Tekkosho);
Co-kneader (manufactured by Buss); TEM extruder (manufactured by Toshiba Machine); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikegai Iron Works); three-roll mill; And a kneader (manufactured by Inoue Seisakusho); Kneedex (manufactured by Mitsui Mining Co., Ltd.); an MS type pressure kneader, a kneader ruder (manufactured by Moriyama Seisakusho); Further, as a sieving apparatus used for sifting coarse particles and the like, Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona sieve, gyro shifter (manufactured by Tokuju Kosakusho); Vibrasonic System (manufactured by Dalton); Shinto Kogyo Co., Ltd.); Turbo Screener (Turbo Kogyo Co., Ltd.); Micro Shifter (Makino Sangyo Co., Ltd.);

Next, a preferred production flow of the toner used in the present invention will be described more specifically with reference to FIGS.

FIG. 3 is an example of a flowchart showing an outline of a method for producing a toner. As shown in the flowchart, the toner production method does not require a classification step before the pulverization treatment, and it is preferable that the pulverization step and the classification step be performed in one pass.

In the method for producing a toner, the number of free magnetic iron oxides and the circularity of the toner can be controlled by producing the toner by using a specific toner constituent material and selecting various production conditions. . In general, a mixture containing at least a binder resin, a colorant and a wax is melt-kneaded, and the obtained kneaded material is cooled. Used as And, first, a rotor composed of a rotating body attached to at least a central rotating shaft with a predetermined amount of the pulverized raw material,
It has a stator disposed around the rotor with a constant spacing between the rotor surface and the rotor, and an annular space formed by maintaining the spacing is configured to be airtight. The pulverized material is finely pulverized by rotating the rotor of the mechanical pulverizer at a high speed. Next, the finely pulverized raw material is introduced into a classification step and classified to obtain a classified product which is a toner raw material composed of a group of particles having a preferable particle size. At this time, in the classification step, a multi-split airflow classifier having at least a coarse powder region, a medium powder region, and a fine powder region is preferably used. For example, when a three-division airflow classifier is used, the powder raw material is classified into at least three types of fine powder, medium powder and coarse powder. In the classifying step using such a classifier, a coarse powder composed of a group of particles having a larger particle size than the preferred particle size and an ultrafine powder composed of a group of particles having a particle size smaller than the preferred particle size are excluded, and the medium powder is used as a toner product. Used as is, or
After being mixed with an external additive such as hydrophobic colloidal silica,
Used as toner.

The ultrafine powder composed of particles having a particle size smaller than the preferred particle size classified in the above-mentioned classification step is generally used in a melt-kneading step for producing a powder raw material composed of a toner material introduced into the pulverization step. To be reused or discarded.

FIG. 4 shows an example of an apparatus system to which the toner manufacturing method is applied, and a more specific description will be made based on this. As a powder raw material which is a toner raw material introduced into this device system, a binder resin, a colored resin particle powder containing at least a colorant and a wax is used, and the powder raw material is, for example, a binder resin, A mixture composed of a magnetic iron oxide and a wax is melt-kneaded, the obtained kneaded product is cooled, and the cooled product is roughly pulverized by a pulverizing means.

In this apparatus system, the pulverized raw material serving as the toner powder raw material is supplied to a mechanical pulverizer 301 serving as a pulverizing means.
A predetermined amount is introduced through the first metering device 315. The introduced pulverized raw material is instantaneously pulverized by the mechanical pulverizer 301 and is introduced into the second constant feeder 2 via the collection cyclone 229. Next, it is supplied into the multi-split airflow classifier 1 as a classifying means via the vibrating feeder 3 and further through the raw material supply nozzle 16.

Usually, the air-flow classifier is used by connecting the mutual devices by a communication means such as a pipe, and is incorporated in an apparatus system. FIG. 4 shows a preferred example of such an apparatus system. The integrated device system shown in FIG. 4 is a means for communicating the multi-divided classifier 1 (the classifier shown in FIG. 8), the quantitative feeder 2, the vibration feeder 3, the collection cyclone 4, the collection cyclone 5, and the collection cyclone 6. Are connected by

In this apparatus system, the powder is fed into the quantitative feeder 2 by appropriate means, and then introduced into the three-division classifier 1 through the vibrating feeder 3 by the raw material supply nozzle 16. For introduction, 10-3
The powder is introduced into the classifier 1 at a flow rate of 50 m / sec. Since the size of the classifying chamber of the three-segment classifier 1 is usually [10 to 50 cm] × [10 to 50 cm], the powder is instantaneously divided into three or more types of particles in 0.1 to 0.01 seconds or less. Can be classified. Then, the particles are classified into large particles (coarse particles), intermediate particles, and small particles by the three-division classifier 1. Thereafter, the large particles pass through the discharge conduit 11a, are sent to the collection cyclone 6, and are returned to the mechanical grinder 301. The intermediate particles are discharged out of the system via the discharge conduit 12a, collected by the collection cyclone 5, and collected as toner. The small particles are discharged out of the system via the discharge conduit 13a, collected by the collection cyclone 4, and supplied to a melt-kneading process for producing a powder material composed of the toner material, and are reused or discarded. Is done. Collection cyclone 4,
5 and 6 can also function as suction pressure reducing means for sucking and introducing the powder into the classification chamber via the raw material supply nozzle 16. In addition, it is preferable that the large particles to be classified at this time are re-introduced into the first quantitative feeder 315, mixed into the powder raw material, and pulverized again by the mechanical pulverizer 301.

In the above-described apparatus system to which the toner manufacturing method is applied, the first classifying step before the pulverizing process is not required, and the pulverizing step and the classifying step can be performed in one pass.

A mechanical pulverizer preferably used as a pulverizing means used in a method for producing a toner will be described. As a mechanical pulverizer, for example, Kawasaki Heavy Industries, Ltd.
Pulverizer KTM, turbo mill manufactured by Turbo Kogyo KK and the like can be mentioned, and it is preferable to use these devices as they are or after appropriately improving them.

Among these, the production of toner by using a mechanical pulverizer as shown in FIGS. 5, 6 and 7 and using specific raw materials as the toner constituent material depends on the shape and free magnetic properties of the toner. This is preferable as a method for controlling the number of iron oxides for production. Further, since the pulverization of the powder raw material can be easily performed, the efficiency can be improved, which is preferable.

In the conventional collision-type airflow pulverization, a free magnetic iron oxide is easily generated at the time of collision because toner particles collide with the collision surface of the collision member and are pulverized by the impact. Further, since the pulverized toner is irregular and angular, the magnetic iron oxide particles are likely to fall off from the toner. It is also possible to modify the shape and surface properties of the particles produced by the impact-type airflow pulverization of the toner by mechanical impact (hybridizer).
In the collision type pulverization, the toner particles collide with the collision surface of the collision member, and the particles are pulverized by the impact, so that free magnetic iron oxide is easily generated at the time of collision. Then, by changing the shape of the particles by mechanical impact and making the shape close to a spherical shape, the magnetic iron oxide particles are less likely to fall off from the toner than the amorphous toner, but the toner using a mechanical pulverizer is used. It is more difficult to control the shape of the toner and the number of free magnetic iron oxides as compared with the production method of (1).

Hereinafter, the mechanical crusher shown in FIGS. 5, 6 and 7 will be described. FIG. 5 is a schematic cross-sectional view of an example of a mechanical pulverizer, and FIG.
FIG. 7 shows a schematic cross-sectional view taken along the plane D ′, and FIG. 7 shows a perspective view of the rotor 314 shown in FIG. The device is shown in FIG.
, The casing 313, the jacket 316, the distributor 220, the casing 313
A rotor 314 in which a number of grooves are provided on a high-speed rotating surface composed of a rotating body attached to a central rotating shaft 312, and a surface arranged at a constant interval on the outer periphery of the rotor 314. Stator 310 having a large number of grooves formed therein, and a raw material inlet 3 for introducing a raw material to be processed.
11, a raw material discharge port 302 for discharging the powder after the treatment.

The pulverizing operation of the mechanical pulverizer constructed as described above is performed, for example, as follows. When a predetermined amount of powder raw material is introduced from the powder inlet 311 of the mechanical pulverizer shown in FIG. 5, particles are introduced into the pulverization processing chamber, and a large number of particles rotate on the surface rotating at high speed in the pulverization processing chamber. The shock generated between the grooved rotor 314 and the stator 310 having a large number of grooves on the surface, the numerous ultra-high speed vortices generated behind the rotor, and the high frequency Instantly crushed by pressure vibration. After that, it is discharged through the raw material discharge port 302. The air (toner) carrying the toner particles passes through the pulverization processing chamber and is discharged out of the system of the apparatus system through the raw material discharge port 302, the pipe 219, the collection cyclone 229, the bag filter 222, and the suction filter 224. Is done. In this manufacturing method, since the powder raw material is pulverized, a desired pulverization treatment can be easily performed without increasing fine powder and coarse powder.

When pulverizing raw materials with a mechanical pulverizer,
Cold air is blown into the mechanical pulverizer together with the powder raw material by the cool air generating means 321 to make the main body of the mechanical pulverizer have a jacket structure 316, and through which cooling water (preferably an antifreeze such as ethylene glycol) flows. Thereby, the atmosphere temperature in the crusher is 0 ° C or less, more preferably -5 to
The temperature is preferably -15 ° C, more preferably -7 to -12 ° C, from the viewpoint of toner productivity.

Cooling water (preferably an antifreeze such as ethylene glycol) is supplied into the jacket from a cooling water supply port 317 and discharged from a cooling water discharge port 318.

When the pulverized raw material is pulverized by a mechanical pulverizer, the room temperature T1 of the spiral chamber 212 and the rear chamber
The temperature difference ΔT (T2−T1) of the room temperature T2 of 21 to 30 to 8
The temperature is preferably 0 ° C, more preferably 35 to 75.
C., more preferably 37 to 72 ° C., it is possible to suppress deterioration of the surface of the toner due to heat, particularly release of magnetic iron oxide present on the toner surface, and it is possible to efficiently pulverize the raw material. If ΔT between the temperature T1 (inlet temperature) and the temperature T2 (outlet temperature) of the mechanical pulverizer is smaller than 30 ° C., a short path may occur without being pulverized, which is not preferable in terms of toner performance. .
If the temperature is higher than 80 ° C., it may be excessively pulverized at the time of pulverization, whereby the magnetic iron oxide is liberated and the surface of the toner is deteriorated due to heat. This is not preferable from the viewpoint of toner productivity.

The peripheral speed of the tip of the rotating rotor 314 is preferably 80 to 180 m / s, more preferably 90 to 170 m / s, and still more preferably 100 to 180 m / s.
160 m / s is preferred from the viewpoint of toner productivity. The peripheral speed of the rotating rotor 314 is 80 to 180 m
/ S, more preferably 90 to 17
By setting the speed to 0 m / s, and more preferably 100 to 160 m / s, insufficient pulverization of the toner, excessive pulverization, and release of magnetic iron oxide due to excessive pulverization can be suppressed, and the pulverized raw material can be efficiently pulverized. . The peripheral speed of the rotor is 80m /
If it is slower than s, it is not preferable from the viewpoint of toner performance because a short path is likely to occur without being ground. Also,
If the peripheral speed of the rotor 314 is higher than 180 m / s, the load on the apparatus itself increases, and at the same time, the magnetic iron oxide is liberated by being over-pulverized during pulverization. Furthermore, excessive pulverization is not preferable in terms of toner productivity because the surface of the toner is deteriorated by heat, particularly, the magnetic iron oxide existing on the toner surface is easily released or fused in the apparatus.

The minimum distance between the rotor 314 and the stator 310 is preferably 0.5 to 10.0 mm, more preferably 1.0 to 5.0 mm, and still more preferably 1.0 to 5.0 mm. It is preferably 3.0 mm. Rotor 3
0.5 to 10.0 m between the stator 14 and the stator 310
m, more preferably 1.0 to 5.
When the thickness is 0 mm, more preferably 1.0 to 3.0 mm, insufficient pulverization of the toner, excessive pulverization, and release of magnetic iron oxide due to excessive pulverization can be suppressed, and the pulverized raw material can be efficiently pulverized. .

The pulverizer used in this production method controls the generation of free magnetic iron oxide by controlling the surface roughness of the pulverized surfaces of the rotor and the stator to an appropriate state, thereby improving the developability. A toner having transferability and chargeability can be obtained. That is, the center line average roughness Ra of the crushed surfaces of the rotor 314 and the stator 310 is 10.0 μm or less, more preferably 2.0 to 10.0 μm, and the maximum roughness Ry is 6 μm.
0.0 μm or less, more preferably 25.0 to 60.0
μm, and the ten-point average roughness Rz is preferably 40.0 μm or less, more preferably 20.0 to 40.0 μm.

Next, an air-flow classifier which is preferably used as a classifying means constituting the toner manufacturing method will be described.

As a preferred example of a multi-split air classifier, an apparatus of the type shown in FIG. 8 (cross-sectional view) is illustrated as a specific example.

In FIG. 8, the side wall 22 and the G block 2
3 forms part of the classification chamber, the classification edge blocks 24 and 25 are provided with classification edges 17 and 18. The installation position of the G block 23 can be slid right and left. Further, the classification edges 17 and 18 correspond to the shaft 17a.
And 18a can be rotated, and the classification edge can be rotated to change the classification edge tip position.
Each of the classification edge blocks 24 and 25 can be slid left and right, and accordingly, the respective knife-edge classification edges 17 and 18 also slide right and left. The classification area 30 of the classification chamber 32 is divided into three by the classification edges 17 and 18.

A raw material supply port 40 for introducing the raw material powder is provided at the rearmost end of the raw material supply nozzle 16, and a high pressure air nozzle 41 and a raw material powder introduction nozzle 42 are provided at the rear end of the raw material supply nozzle 16. And a raw material supply nozzle 16 having an opening in the classifying chamber 32 is provided on the right side of the side wall 22, and the Coanda block 26 is installed so as to draw an oblong arc with respect to the extension direction of the lower tangent of the raw material supply nozzle 16. Have been. The left block 27 of the classifying chamber 32 has a knife-edge type air inlet edge 19 on the right side of the classifying chamber 32, and further, on the left side of the classifying chamber 32, the inlet pipes 14 and 1 that open to the classifying chamber 32.
5 is provided. In addition, as shown in FIG.
And 15 include a first gas introduction adjusting means 2 such as a damper.
Zero and second gas introduction adjusting means 21 and static pressure gauges 28 and 29
Is provided.

The positions of the classification edges 17, 18, the G block 23, and the inlet edge 19 are adjusted according to the type and desired particle size of the toner to be classified.

Further, on the upper surface of the classifying chamber 32, the outlets 11, 1 opening into the classifying chamber corresponding to the respective dividing areas.
Each of the outlets 11, 12 and 13 is connected to a communicating means such as a pipe, and each of the outlets may be provided with an opening / closing means such as a valve means.

The raw material supply nozzle 16 is composed of a right-angled cylinder and a pyramidal cylinder. The ratio of the inner diameter of the right-angled cylinder to the inner diameter of the narrowest part of the pyramidal cylinder is 20: 1 to 1: 1, preferably 10: 1. : 1
If the ratio is set to 2: 1 from, a good introduction speed can be obtained.

The classification operation in the multi-division classification region configured as described above is performed, for example, as follows. Outlet 11, 1
The pressure in the classification chamber is reduced through at least one of 2 and 13, and the air flow flowing through the raw material supply nozzle 16 having an opening in the classification chamber due to the reduced pressure and the high-pressure air supply nozzle 4
Due to the ejector effect of compressed air injected from 1,
Preferably, the powder is injected into the classification chamber through the raw material supply nozzle 16 at a flow rate of 10 to 350 m / s, and dispersed.

The particles in the powder introduced into the classifying chamber move on a curved surface by the action of the Coanda effect of the Coanda block 26 and the action of gas such as air flowing in at that time. Depending on the particle size and the magnitude of the inertial force, large particles (coarse particles) are outside the airflow, ie, the first fraction outside the classification edge 18, and intermediate particles are the second fraction between the classification edges 18 and 17. Classification edge 1 for small particles
7, the classified large particles are discharged from the outlet 11, the classified intermediate particles are discharged from the outlet 12, and the classified small particles are discharged from the outlet 13. Is discharged.

In the above-described classification of the powder, the classification point is mainly determined by the edge tip positions of the classification edges 17 and 18 with respect to the lower end of the Coanda block 26 where the powder jumps into the classification chamber 32. Further, the classification point is affected by the suction flow rate of the classification airflow, the powder ejection speed from the raw material supply nozzle 16, and the like.

In this production method and production system, by controlling the conditions of pulverization and classification, a toner having a weight average diameter of 5 to 10 μm and a sharp particle size distribution can be efficiently produced.

Next, the heat and pressure fixing device used in the present invention will be described.

The heat and pressure fixing device used in the present invention is
Heat and pressure for applying heat energy to the heating member by nipping and conveying the member to be heated between the heat-resistant film and the pressing member arranged to be in pressure contact with the heating body via the heat-resistant film. A fixing device, wherein the pressing member has a thermal conductivity of 0.20 W / m · k or less, more preferably 0.05
It has a heat-resistant elastic layer of about 0.20 W / m · k. Further, a fixing member having a fixing speed of 55 mm / sec or more, more preferably 55 to 250 mm / sec, and a power consumption of the heating member of 0.40 to 0.70 Wh / sheet is more preferably used.

When the heat conductivity is lower than that of the conventional pressure roller, heat is more easily held on the roller surface than in the conventional pressure roller, and this has a very effective effect on low-temperature fixability. Further, since the toner adhering to the roller surface is easily softened again, the toner can be transferred to the paper little by little, so that the toner is not excessively accumulated on the pressure roller. Incidentally, the surface temperature of the pressure roller during image formation is usually 100 ° C to 150 ° C,
It almost coincides with the endothermic peak in DSC of the toner used in the present invention. The use of the pressure roller of the present invention makes it possible to achieve good fixability and reduce pressure roller contamination even when the fixing speed is 55 mm / sec or more.
Further, the power consumption of the heating member of the present invention can be suppressed to 0.4 to 0.7 Wh / sheet. On the other hand, there is also a problem that the temperature of a portion where the small size paper does not pass after the continuous copying of the small size paper is severe and the A4 size paper or the like is copied immediately after that, and the offset tends to occur in that portion. is there.

The power consumption was measured as follows.
In an environment of 23 ° C. and 60% RH, the heater temperature is 2
After the temperature reached 00 ° C., the power consumption until the recording material entered the nip and passed through the nip was measured, and the power consumption per printed image was determined.

FIG. 1 is a schematic cross-sectional view of an example of a tensionless film heating type heat fixing device for carrying out the present invention.

Reference numeral 701 denotes a resin-made horizontally long stay, which serves as an inner surface guide member of a film described later. An endless heat-resistant film 702 is circumscribed to a stay 701 including a heating element 703. A stay 70 including the inner peripheral length of the endless heat-resistant film 702 and the heating element 703
The outer peripheral length of the film 702 is larger than that of the film 702 by, for example, about 3 mm.
The outer circumference loosely circumscribes the stay 701 with the margin.

In order to reduce the heat capacity and improve the quick start property, the film 702 is used.
Has a thickness of about 100 μm or less, and is a single layer of PTFE, PFA, FEP having heat resistance, release property, strength, durability, etc., or polyimide, polyamide, PEEK,
PTFE, PFA, FE on the outer surface of PES, PPS, etc.
A laminated film coated with P or the like can be used.

In the present embodiment, the heat-resistant film 7
For 02, the outer peripheral surface of a 50 μm polyimide film was coated with 10 μm PTFE, and the layer thickness was 60 μm.
m was used.

Reference numeral 703 denotes a heating element, which is made of an electric resistance material such as Ag / Pd (silver-palladium) as a heating element along a substantially central portion of a base made of alumina, having a thickness of about 10 μm and a width of 1 to 1 mm. A 3 mm coating is formed by screen printing, and a glass or fluorine resin is coated thereon as a protective layer. A thermistor for the heating element is provided on the opposite side of the heating element from the fixing film, and the temperature of the heating element 703 is controlled by the temperature detected by the thermistor.

The pressure roller 706 is a rotating body which forms a fixing nip portion with the film 2 sandwiched between the heating roller 703 and the film 2 and drives the film.
They are connected by a core bar made of aluminum. The pressure roller 706 rotates by transmitting a driving force from a driving motor of a driving device.

The recording material P as a heated object is transferred by heating / pressing the toner image T by being conveyed and passed through a fixing nip portion formed with a film interposed between a pressure roller and a heated body. The recording material P is fixed on the recording material P.

The pressure roller 706 according to the present embodiment
A 240 mm long, 3 mm thick, heat-resistant elastic layer was formed on an aluminum core bar having an outer diameter of 13 mm connected to a driving device.
It is coated with a silicone foam having a thermal conductivity of 0.1 W / mk. The measurement of thermal conductivity was made by Kyoto Electronics Industry Co., Ltd.
The measurement was performed using a rapid thermal conductivity meter QMT-500. The object to be measured was measured using an actual pressure roller.

The heat conductivity of the heat-resistant elastic layer is 0.1 W / m
It is preferably k or less, and by using the pressure roller of the configuration of the present embodiment, heat is not taken away by the pressure roller itself and the heating start-up time does not increase.
In addition, excessive power consumption is eliminated, and the fixing property is improved immediately after the power is turned on.

As the material used for the heat-resistant elastic layer coated on the pressure roller, fluorine rubber, silicone rubber, silicone rubber foam, melamine foam, and silicone foam are preferably used. More preferred are silicone rubber foam, melamine foam, and silicone foam.

Next, an example of an image forming apparatus is schematically shown in FIG. 2, and an image forming method will be described based on the schematic.

Reference numeral 501 denotes a drum-shaped electrostatic latent image carrier, around which a charging roller (charging member) 502 of primary charging means, an exposure optical system 503, and a toner carrier 50 are provided.
5, a developing unit 504, a transfer unit 509, and a cleaning unit 511 are disposed.

In this image forming apparatus, the surface of the electrostatic latent image carrier 501, which is a photosensitive member, is uniformly charged by the charging roller 502, and is then exposed by the exposure optical system 503 to expose the electrostatic latent image carrier 501. To form an electrostatic latent image on the surface of the substrate.

The shape of the charging member is not particularly limited as long as it is a contact charging member that is arranged in contact with the electrostatic image carrier, and may be a roller, a blade, or a brush.

The voltage applied to the charging member is preferably such that the DC voltage has an absolute value of 200 to 2000 V, and the AC voltage has a peak-to-peak voltage of 400 to 4000 V.
Preferably, the frequency is between 200 and 3000 Hz.

Next, the toner carrier 50 containing a magnet
5, a toner coat layer is formed by a toner layer thickness regulating member 506, and the electrostatic latent image carrier 5 is formed in a developing section.
The electrostatic latent image formed on the electrostatic latent image carrier 501 is developed while applying an alternate bias, a pulse bias, and / or a DC bias by the bias applying means 508 between the conductive substrate No. 01 and the toner carrier 505. I do. In the figure, 50
Reference numeral 7 denotes a stirring unit, and 513 denotes a magnetic toner.

The developed toner image is conveyed by a transfer sheet P as a transfer material, and charged by a transfer roller 509 as a transfer unit and a charge having a polarity opposite to that of the toner from the back surface of the transfer sheet P by a voltage applying unit 510. Is electrostatically transferred to the transfer paper P.

The transfer paper P on which the toner image has been transferred passes through the heating / pressing roller fixing device 512, and the toner image becomes a fixed image.

The toner remaining on the latent image carrier after the transfer step is removed by a cleaning blade 511 as a cleaning means and collected by a cleaner 514.
The steps following the primary charging are repeated again.

[0135]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples. “Parts” means parts by mass.

Example 1 First, the preparation of the toner will be described.

Binder resin 100 parts (70 parts of styrene-butyl acrylate copolymer having a weight average molecular weight of 12000 and 30 parts of styrene-butyl acrylate copolymer having a weight average molecular weight of 600,000 are mixed; molecular weight of main peak: 15 000, molecular weight of sub-peak: 750,000, ratio of weight average molecular weight to number average molecular weight (Mw / Mn) = 33, molecular weight 1000 to 10,000: 35%) 100 parts of magnetic material (Fe ₃ O ₄ ) 100% charged Control agent (monoazo iron complex) 2 parts Wax W1 (polypropylene wax, melting point 139 ° C.) 5 parts The above mixture is melt-kneaded with a twin-screw extruder heated to 130 ° C., and the cooled kneaded material is coarsely milled with a hammer mill. Crushed.

According to the toner production flow shown in FIGS. 3 and 4, the coarsely pulverized product was subjected to Turbo Mill T-250 manufactured by Turbo Kogyo.
The material was finely pulverized using a mold, and the finely pulverized material was classified using an elbow jet classifier (manufactured by Nippon Steel Mining Co., Ltd.).

100 parts of the obtained middle powder was added to hydrophobic silica fine powder (BE) treated with silicone oil.
T specific surface area 110 m ² / g, average particle size 25 nm) 1.2
And 0.4 part of strontium titanate fine powder (BET specific surface area: 2 m ² / g, average particle size: 1.5 μm) were added and mixed with a Henschel mixer to obtain a magnetic toner. The physical properties of the toner are shown in Tables 1 and 2.

As the image forming apparatus shown in FIG. 2, the process speed and the fixing speed were modified to 60 mm / sec by using LBP “LJ-6L” manufactured by Hewlett-Packard Company.
Further, the fixing device is configured as shown in FIG. 1 (pressure roller: outer diameter of core metal 13 mm, heat-resistant elastic layer: silicone rubber foam, thickness 3 mm, single-layer structure, heat conductivity of heat-resistant elastic layer:
The fixing device T1 was modified to 0.1 W / m · k). The above-mentioned toner was set in a process cartridge of this modified model of “LJ-6L”, and was evaluated according to the following image evaluation method. The results are shown in Tables 1 and 2.

A contact charging roller was used. DC voltage: -625 V, AC voltage: peak-to-peak voltage,
The J-6L "modified machine has a contact pressure of 1.8 kV and a frequency of 370 Hz as a primary charging member, which comes into contact with the OPC photoreceptor surface.
Is an image forming apparatus having a configuration in which the OPC photosensitive member is primarily charged by applying a charging voltage of OPC.

The image evaluation was performed as follows.

(1) Fixing property The fixing property is determined after the main unit power is turned on when the fixing device is sufficiently cooled in a low-temperature and low-humidity environment (7.5 ° C., 10% RH).
4.9 × 10 ^-3 MP for the image fixed and printed on the sheet
a, and rub the fixed image with soft thin paper,
The worst value of the rate of decrease (%) in image density before and after rubbing was evaluated. Test paper is Plover Bond (90 g / m ² )
It was used. A (excellent): less than 5% B (good): 5 to 10% C (acceptable): 11 to 20% D (bad): 21% or more

(2) Offset Resistance The offset resistance is determined by printing 30 continuous envelopes, printing out a sample image of solid black on the upper half surface by A4 lengthwise feed,
The evaluation was made based on the degree of smear on the unprinted solid white portion on the image. (64 g / m ² ) was used as test paper. A (excellent): not generated B (good): hardly generated C (acceptable): slightly generated (no problem in practical use) D (bad): dirty

(3) Pressure roller dirt The pressure roller dirt was measured by Boise Cascade X-
9000 was used as a test paper, and was used in a low-temperature, low-humidity environment (15 ° C, 10
% RH), the degree of toner contamination on the members inside the fixing device and the image at the end of the printout of 1000, 2000, and 3000 sheets was visually evaluated. A (excellent): there is no dirt on the pressure roller and there is no dirt on the image B (good): there is almost no dirt on the pressure roller and there is no dirt on the image C (good): dirt on the pressure roller There is no dirt on the image, but D (bad): There is dirt on the pressure roller and dirt on the image

Example 2 As the wax, Fischer-Tropsch wax W2 was used.
(Melting point: 105 ° C.) Using the toner obtained in the same manner as in Example 1 except that 5 parts of the toner were used, image evaluation was performed by the same evaluator as in Example 1. The results are shown in Tables 1 and 2.

Example 3 As wax, paraffin wax W3 (melting point: 78 ° C.)
Example 1 except that 2 parts of W1 and 3 parts of W1 wax were used.
The image evaluation was performed using the same ones as in the above. The results are shown in Tables 1 and 2.

Comparative Example 1 In the pulverization step, an air jet pulverizer (I-5) was used as the toner using polyalcohol wax W4 (melting point 98 ° C.).
Example 1 except using a mold (made by Nippon Pneumatic)
The toner produced in the same manner as described above was used. With respect to the pressure roller, a fixing device T2 using the following was manufactured.・ Core metal outer diameter 13mm ・ Heat-resistant elastic layer Silicone rubber 3mm thick ・ Release layer Fluorine rubber 50μm thick 2-layer structure ・ Heat-resistant elastic layer + Thermal conductivity of release layer 0.3W / m ・ k

Evaluation was performed in the same manner as in Example 1 using the toner and the fixing device T2. Tables 1 and 2 show the results.
Shown in

Comparative Example 2 The toner was composed of a styrene-butyl acrylate copolymer having a main peak molecular weight of 28,700, a sub peak molecular weight of 835,000, an Mw / Mn of 29, and a molecular weight of 1,000 to 10,000 having an abundance of 18%. The procedure of Example 1 was repeated, except that a binder resin was used, and an air jet pulverizer (Model I-5, manufactured by Nippon Pneumatic) was used in the pulverization process. The evaluation was performed using the fixing device used in Comparative Example 1. The results are shown in Tables 1 and 2.

[0151]

[Table 1]

[0152]

[Table 2]

[0153]

According to the present invention, good fixing performance can be maintained by using a fixing means having a toner having a specific DSC endothermic peak and a molecular weight distribution in GPC and a pressure roller having a specific thermal conductivity. In addition, it has become possible to provide an image forming method and an image forming toner in which offset resistance and pressure roller contamination do not occur.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of the configuration of a tensionless film heating type heat fixing device according to the present invention.

FIG. 2 is a diagram schematically illustrating an example of an image forming apparatus used in the image forming method of the present invention.

FIG. 3 is a flowchart illustrating a method for manufacturing a toner.

FIG. 4 is a schematic diagram illustrating a specific example of an apparatus system for performing a toner manufacturing method.

FIG. 5 is a schematic sectional view of an example of a mechanical pulverizer used in a toner pulverization step.

FIG. 6 is a schematic sectional view taken along the line DD ′ in FIG. 5;

FIG. 7 is a perspective view of the rotor shown in FIG. 5;

FIG. 8 is a schematic sectional view of a multi-split airflow classifier used in a toner classifying step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-division classification apparatus 301 Mechanical pulverizer 501 Electrostatic image carrier 502 Primary charging apparatus 503 Exposure optical system 504 Developing apparatus 505 Toner carrier 506 Toner layer thickness regulating member 507 Toner stirring means 508 Developing bias power supply 509 Transfer apparatus 510 Transfer Current generator 511 Cleaning means 512 Fixing device 513 Toner 516 Process cartridge 701 Stay 702 Heat resistant film 703 Heating body 706 Pressure roller T Toner P Transfer material (recording material)

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H005 AA06 AA08 AA15 AB04 CA12 CA13 CA14 CB13 EA03 EA06 EA07 FB01 2H033 AA09 BA25 BA58 BB29 BE03 CA30 CA44

Claims (18)

[Claims] 1. A transfer material having a toner image formed of toner is sandwiched and conveyed between a heating member having a heat-resistant film that rotates and a pressing member, and the toner image is heated and pressed on the transfer material. In the image forming method having a fixing step of fixing, the pressing member has a heat-resistant elastic layer having a heat conductivity of 0.20 W / m · K or less on a cored bar, and a fixing speed of 5 mm.
5 mm / sec or more, the power consumption of the heating member is 0.40 to 0.70 Wh / sheet, and the toner contains toner particles containing at least a binder resin, a colorant and a wax, and an external additive. The toner has at least a maximum value in a temperature range of 105 to 150 ° C. in a DSC endothermic curve, a main peak in a molecular weight region of 2,000 to 25,000 in GPC of a THF-soluble component of the toner, and a molecular weight of 70,000. An image forming method, comprising a subpeak or a shoulder in the above region, Mw / Mn of 8 or more, and 20 to 70% of components in a region having a molecular weight of 1,000 to 10,000. 2. The image forming method according to claim 1, wherein the toner has a maximum value even in a temperature range of 60 to 100 ° C. in an endothermic curve of DSC. 3. The image forming method according to claim 1, wherein the external additive comprises hydrophobic silica having at least silicone oil. 4. The toner has at least 90% by number of particles having a circularity a of 0.900 or more determined by the following formula (A) and a circularity a of 0.950. The above particles are present in a number-based cumulative value of 67% by number or more,
In addition, particles having a circularity a of 0.995 or more are present in a number-based cumulative value of 8% by number or more, and the circularity a is 0.99 or more.
4. The method according to claim 1, wherein the abundance of 5 or more particles occupies 12% by number or more of the cumulative value based on the number of particles having a circularity a of 0.950 or more. Image forming method. (Equation 1) (In the formula, L ₀ indicates the perimeter of a circle having the same projected area as the particle image, and L indicates the perimeter of the particle image.) 5. The toner is produced through a melt-kneading step, a fine pulverizing step, and a classifying step, and is obtained by melt-kneading a mixture containing at least a binder resin and a colorant. After cooling, the cooled material is coarsely pulverized by a pulverizing means, and the obtained powdery raw material of the coarsely pulverized material is introduced into a first constant-volume feeder, and at least a rotor that is a rotating body attached to a central rotation shaft And a stator disposed around the rotor while maintaining a constant interval with the rotor surface, and the annular space formed by maintaining the interval is configured to be airtight. A predetermined amount of powder raw material is introduced into the mechanical pulverizer through the powder inlet of the mechanical pulverizer from the first metering device, and the rotor of the mechanical pulverizer is rotated at a high speed. The powder raw material is finely pulverized by The pulverized material is discharged from the powder discharge port of the mechanical pulverizer and introduced into the second metering device. A predetermined amount of the fine material is used from the second metering device, utilizing the crossed airflow and the Coanda effect. Into a multi-divided airflow classifier that classifies the powder into air, and classifies the finely pulverized product into at least fine powder, medium powder, and coarse powder in the multi-divided airflow classifier, and classifies the coarse powder. 5. The image forming method according to claim 4, wherein the toner is a toner produced from a medium powder obtained by mixing the powder with a raw material, introducing the powder into the mechanical pulverizer, and pulverizing the powder. 6. The multi-split air flow classifier includes a raw material supply nozzle, a raw material powder introduction nozzle, and a high-pressure air supply nozzle on an upper surface of the multi-split air flow classifier, and performs classification in the multi-split air flow classifier. Classification edge block with edge,
The image forming method according to claim 5, wherein the image forming method is a multi-split airflow classifier whose position can be changed so that the shape of the classification area can be changed. 7. The pressure member is a pressure roller, and the pressure roller has a surface temperature of 110 to 160 ° C. and a melting point of 105 ° C.
7. The image forming method according to claim 1, wherein the toner contains wax at a temperature of from 155 to 155 [deg.] C. 8. The toner according to claim 1, wherein the toner contains a wax having a melting point of 110 to 150 ° C.
The image forming method according to any one of the above. 9. The pressure member is a pressure roller, and the pressure roller has a surface temperature of 110 to 150 ° C. and a melting point of 110 ° C.
2. The toner according to claim 1, wherein the toner contains a wax having a melting point of 60 to 95 [deg.] C. and a wax having a melting point of 60 to 95 [deg.] C.
7. The image forming method according to any one of claims 1 to 6. 10. The image forming method according to claim 1, wherein the wax is contained in the toner in an amount of 0.5 to 30 parts by mass based on 100 parts by mass of the binder resin. 11. The image forming method according to claim 1, wherein the wax is contained in the toner in an amount of 2 to 10 parts by mass based on 100 parts by mass of the binder resin. 12. The image according to claim 1, wherein the toner has an endothermic peak in a temperature range of 60 to 90 ° C. and a temperature range of 110 to 150 ° C. in a DSC endothermic curve. Forming method. 13. A transfer material having a toner image formed of toner is sandwiched and conveyed between a heating member having a heat-resistant film that rotates and a pressing member, and the toner image is heated and pressed on the transfer material. The pressing member has a heat-resistant elastic layer having a thermal conductivity of 0.20 W / m · K or less on a cored bar, and a fixing speed of 55 mm / sec.
As described above, in the toner for the image forming method used in the image forming method in which the power consumption of the pressing member is 0.40 to 0.70 Wh / sheet, the toner is a binder resin,
The toner has toner particles containing at least a colorant and a wax, and an external additive. The toner has at least a maximum value in a temperature range of 105 ° C. to 150 ° C. in a DSC endothermic curve. GPC has a main peak in a molecular weight region of 2,000 to 25,000, a subpeak or a shoulder in a molecular weight region of 70,000 or more, Mw / Mn of 8 or more, and a molecular weight of 10
A toner for an image forming method, comprising 20 to 70% of a component in an area of 00 to 10,000. 14. The toner according to claim 13, wherein the toner has a maximum value in a temperature range of 60 to 100 ° C. in an endothermic curve of DSC. 15. The toner according to claim 13, wherein the external additive has hydrophobic silica having at least silicone oil. 16. The toner has 90% by number or more of particles having a circularity a of 0.900 or more determined by the following formula (A) as a number-based cumulative value and a circularity a of 0.950.
The above particles are present in a number-based cumulative value of 67% by number or more, and the particles having a circularity a of 0.995 or more are present in a number-based cumulative value of 8% or more, and the circularity a is 0 or more. .
16. The method according to claim 13, wherein the abundance of particles having a circularity a of not less than 995% of the cumulative value based on the number of particles having a circularity a of not less than 0.950 is not less than 995. Toner for an image forming method. (Equation 2) (In the formula, L ₀ indicates the perimeter of a circle having the same projected area as the particle image, and L indicates the perimeter of the particle image.) 17. The kneaded product obtained by melting and kneading a mixture containing at least a binder resin and a colorant, the toner being produced through a melt-kneading step, a fine pulverizing step and a classification step. After cooling, the cooled material is coarsely pulverized by a pulverizing means, and the obtained powdery raw material of the coarsely pulverized material is introduced into a first constant-volume feeder, and at least a rotor which is a rotating body attached to a central rotating shaft. And a stator disposed around the rotor while maintaining a constant interval with the rotor surface, and the annular space formed by maintaining the interval is configured to be airtight. A predetermined amount of powder raw material is introduced into the mechanical pulverizer through the powder inlet of the mechanical pulverizer from the first metering device, and the rotor of the mechanical pulverizer is rotated at a high speed. By pulverizing the powder raw material, The finely pulverized material is discharged from the powder discharge port of the mechanical pulverizer and introduced into the second metering device. A predetermined amount of the finely pulverized material is crossed from the second metering device to reduce cross airflow and Coanda effect. The powder is introduced into a multi-divided airflow classifier that classifies the powder by air flow, and the finely pulverized material is classified into at least a fine powder, a medium powder, and a coarse powder in the multi-divided airflow classifier, and the classified coarse 17. The image forming method according to claim 16, wherein the powder is mixed with a powder raw material, introduced into the mechanical pulverizer, pulverized, and classified into a medium powder. toner. 18. The multi-split airflow classifier includes a raw material supply nozzle, a raw material powder introduction nozzle, and a high-pressure air supply nozzle on an upper surface portion of the multi-split airflow classifier. 18. The toner for an image forming method according to claim 17, wherein the classification edge block having an edge is a multi-divided airflow type classification machine whose position can be changed so that the shape of the classification area can be changed.