JP6708399B2 - Toner manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a toner used in a recording method using electrophotography or the like .

Many electrophotographic methods are known. Generally, a photoconductive substance is used to form an electrostatic latent image on an electrostatic charge image carrier (hereinafter, also referred to as “photoreceptor”) by various means. Then, the latent image is developed with toner to form a visible image, and the toner image is transferred to a recording medium such as paper as necessary, and then the toner image is fixed on the recording medium by heat or pressure to make a copy. Is what you get. Image forming apparatuses using such electrophotography include copying machines and printers.
These printers and copiers are required to have excellent image reproducibility and high resolution, and stable image quality even during long-term use, as the transition from analog to digital progresses. Further, there is a demand for a toner having a good developing property and a good fixing property even when the paper feeding speed is increased, and the improvement of the binder resin and the improvement of the releasing agent have been made.

Considering the behavior during fixing, first, unfixed toner is placed on a medium such as paper. Next, when the unfixed toner passes through the fixing device, the toner melts and deforms, and the release agent oozes out onto the toner surface, so that the particles are bound to each other or anchored to the media such as paper. Then, the toner is fixed. One of the driving forces for fixing the toner is the heat received from the heat source of the fixing device through the fixing film when the toner passes through the fixing nip portion formed by the fixing film and the pressure roller. The other is the pressure received from the pressure roller when passing through the fixing nip portion. After passing through the fixing nip, the toner is released from the fixing film and fixed on the paper.
In the next-generation machine in which the sheet feeding speed is increased, the time taken for the toner to pass through the fixing nip portion is shortened, so that the heat amount and the pressure received by the toner are reduced. At this time, it becomes difficult to solve the problem of peeling.
In the present invention, “peeling” is a phenomenon in which a printed image does not become fixed on a sheet of paper and a printed image becomes white. This phenomenon is likely to occur in the concave portion at the rear end of the high printing rate image. The reason for this is that the higher the printing rate of the image, the smaller the amount of heat received by one toner particle because the amount of heat from the fixing device is dispersed in more toner. Further, there is a reason that the amount of heat given from the fixing device tends to be smaller toward the rear end of the paper, and the pressure applied by the pressure roller becomes weaker in the concave and convex portions of the paper.

On the other hand, in the convex portion of the front end of the paper of the low printing rate image, since the heat and pressure applied to the toner are large, the toner tends to be melted and deformed, and the problem that the fine line is crushed is likely to occur. .. Hereinafter, in the present invention, this phenomenon is called collapse.
In the next-generation machine in which the paper feeding speed is increased, the amount of heat and pressure received by the toner are small as described above, and thus peeling easily occurs. Therefore, a toner design that suppresses peeling is required, but at that time, there is a concern that crushing tends to occur. Therefore, in order to solve the problems of peeling and crushing at the same time in the next-generation high-speed machine, there is a technique to improve the fixing performance at the concave portion at the rear end of the paper without deforming the toner too much at the convex portion at the front end of the paper. It has been demanded.

Focusing on the release agent, it is generally known that the fixing property is improved by increasing the amount of the release agent in the toner. However, when a large amount of the release agent is used, the binder resin contains a large amount of low-molecular weight components, and the heat-resistant storability may decrease. For example, when it is stored in a harsh environment where the temperature and humidity are higher than usual, the release agent compatible with the binder resin causes bleeding and bleeds to the toner surface. The above environment is called a harsh environment, and leaving the toner in that environment is called a harsh environment. When this problem occurs, the exposed amount of the release agent on the surface of the toner after being left in a harsh environment increases, which affects the charging stability and the fluidity of the toner, and the developing performance such as the density is significantly reduced. Sometimes.
As described above, in the next-generation high-speed machine, it is a difficult task to solve the problem of toner peeling and crushing of fine lines and the developability after being left in a harsh environment.
In order to solve these problems, it has been studied to control the presence state of the domain of the release agent in the toner to effectively exhibit the release performance with respect to the amount of the release agent. In particular, the domain diameter and area ratio of the release agent have already been studied.
In Patent Document 1, two types of release agents are used in combination, and two peaks of domain diameter are present to improve low-temperature fixability.
In Japanese Patent Laid-Open No. 2004-242242, the proportion of the cross-sectional area of the release agent domain in the toner cross section is defined to improve the low-temperature fixability.

JP 2006-84674 A JP, 2008-145568, A

However, as described above, when aiming to increase the paper feed speed in the next-generation machine, in order to solve the problems of peeling and fine line crushing at the same time, and to achieve developability after being left in a harsh environment, it is still under study. There is room.
An object of the present invention is to solve the above problems. Specifically, in a next-generation high-speed machine, there is little image peeling or crushing of fine lines, and it is possible to provide a toner that can obtain a stable image with good image density even after use in a harsh environment. is there.

A method for producing a toner, the method comprising producing a toner having toner particles containing a binder resin, a release agent and a colorant,
The manufacturing method is
A step of producing the toner particles,
The crystallization temperature of the release agent is Tc (°C), and the glass transition temperature of the toner particles is Tg (°C).
), the aqueous medium in which the toner particles are dispersed is referred to as Tc (°C) and Tg (°C).
A process of cooling from a higher temperature to a temperature below the Tg (°C) at a cooling rate of 5.00°C/min or more.
(I) and
The water-based medium that has undergone the step (i) is treated in the temperature range of ±10°C of the Tg (°C) in 3
A step of holding for 0 minutes or more (ii),
In that order,
In the toner of the cross section was observed by scanning transmission electron microscopy,
The release agent forms a domain,
The major axis of the cross section of the toner is R (μm), the major axis of the domain of the release agent present in the cross section of the toner is r (μm), and r/R of the domains of the release agent is 0. When the domain of 125≦r/R≦0.375 is the domain A and the domain of r/R is 0.000625≦r/R≦0.0625 is the domain B, the phase of the major axis R of the cross section of the toner is determined. The average value satisfies 4≦R≦12,
In the cross section of the toner, when the ratio of the area occupied by the domain A is SA and the ratio of the area occupied by the domain B is SB, the SA and the SB satisfy the following formulas (1) and (2). ,
2.5%≦SA≦30% (1)
0.1≦SB/SA≦0.8 (2)
A method for producing a toner , wherein an aspect ratio of the domain B in the toner cross section is 0.3 or less.

According to the present invention, it is possible to provide a toner in which peeling of an image and collapse of a fine line are small, and a stable image having a good image density can be obtained even when used after being left in a harsh environment.

The figure which shows the temperature transition of the severe environment leaving of the example FIG. 1 illustrates an example of an image forming apparatus

The present invention is
A toner containing a binder resin, a release agent and a colorant,
In the cross section of the toner observed with a transmission electron microscope,
The release agent forms a domain,
The major axis of the toner cross section is R (μm),
Let r be the major axis of the release agent domain present in the toner cross section,
Among the domains of the release agent, a domain having r/R of 0.125≦r/R≦0.375 is defined as a domain A, and a domain of r/R of 0.000625≦r/R≦0.0625 is defined as a domain. When we say B,
The arithmetic mean value of the major axis R of the toner cross section satisfies 4≦R≦12,
When the ratio of the area occupied by the domain A in the toner cross section is SA and the ratio of the area occupied by the domain B is SB, the following formulas (1) and (2) are satisfied,
2.5%≦SA≦30% (1)
0.1≦SB/SA≦0.8 (2)
The aspect ratio of the domain B in the toner cross section is 0.3 or less.

According to the present inventors, by using the above toner, peeling of the trailing edge of the paper at the time of high-printing rate image printing and crushing of fine lines are small, and a stable image is obtained even after use in a harsh environment. It is possible to provide a toner capable of obtaining an image having a good density.
First, the phenomenon of peeling will be described. As described above, peeling is a phenomenon in which, in a high-printing-rate image in which the amount of heat and the pressure applied to the toner are small, the toner is not fixed to the paper and the image becomes white in the concave portion at the rear end of the paper. This is because the amount of heat and pressure that the toner receives at the time of fixing is small, so the release agent does not exude sufficiently to the toner surface, and the effect of adhering to paper and the effect of releasing from the fixing film are not exhibited. It is thought to occur.
Next, the phenomenon of collapse will be described. As described above, the crushing is a phenomenon in which the printed fine line is crushed at the convex portion of the front end of the paper having a large amount of heat and pressure applied to the toner. This phenomenon is caused by a large amount of heat and pressure at the time of fixing, which causes the release agent of the toner to be deformed to be compatible with the binder resin of the toner and soften the resin, so that the toner is largely melted and deformed. ..
As described above, there is a trade-off relationship between peeling caused by a small amount of heat and pressure applied to the toner and crushing caused by a large amount of heat and pressure applied to the toner.

Based on these mechanisms, the present inventors suppress the excessive melting deformation of the toner at the time of fixing and simultaneously exude the release agent onto the surface of the toner in order to solve the problems of peeling and crushing. It was found that depending on the toner composition used, both peeling and crushing can be suppressed.
Specifically, the above-mentioned toner can be achieved by dispersing a release agent having a large domain and a release agent having a small domain inside the toner and controlling the shape of the smaller domain into a needle shape.

In this configuration, since the small needle-like domain has a small volume in the short axis direction, it does not cause large melt deformation of the toner when receiving heat. Therefore, it is possible to suppress excessive melting and deformation of the toner during fixing. Further, when the toner receives heat and the large domains ooze out to the surface, the small needle-like domains can be used as a path to quickly transfer to the toner surface. Since the small domains are needle-shaped, they have a large surface area with respect to the amount of the release agent and can easily function as a passage. Thereby, the amount of the release agent on the surface of the toner at the time of fixing can be significantly increased. That is, the release agent can be quickly exposed without excessively deforming the toner during fixing. Further, since the release agent is exuded onto the surface of the toner only when a large amount of heat is applied during fixing, the storage stability at 50° C. is good.
As a result, the release agent oozes out onto the surface quickly without excessive melt deformation during fixing, so the problems of peeling and crushing of fine lines can be solved at the same time, and a toner with good heat-resistant storability can be obtained. You can

The domain of the release agent in the present invention will be described. By ruthenium dyeing the cross section of the toner and observing with a STEM, a sea-island structure formed from sea parts of the binder resin and island parts of the release agent can be seen. Here, when the island portion of the release agent is enlarged, it is possible to observe the lamella of the release agent. One island formed by this lamella is called a domain.
In the present invention, as described above, the domain (r/R) of the release agent satisfies the domain of 0.125≦(r/R)≦0.375, and the domain A of the release agent, and 0.000625. The toner has a domain B of the release agent satisfying ≦(r/R)≦0.0625. That is, in the toner in which the domain A and the domain B of the release agent are present at the same time, the domain B having a sufficient total area exists with respect to the domain A having a sufficient size for exhibiting the release performance. It has a structure.
In the present invention, in the cross section of the toner, the arithmetic mean value of the major axis R (μm) of the cross section of the toner is preferably 4 μm or more and 12 μm or less, and more preferably 5 μm or more and 10 μm or less. When the major axis R is in the above range, it is possible to improve the charging stability and fixing property of the toner. The major axis R can be controlled by the number of dispersion stabilizer parts, the rotation speed of the TK homomixer, and the like.

In the toner of the present invention, the (r/R) of domain A is 0.125≦(r/R)≦0.375. The release agent expands in volume when it receives heat during fixing. When the domain A is in the above range, it can effectively exude to the toner surface. The toner of the present invention may have a plurality of domains A in the cross section. At that time, the effect of the present invention can be obtained by satisfying the above-mentioned longest diameter and having the area ratio SA of the domain A of the toner cross section of 2.5%≦SA≦30%. When the major axis or area of the domain A is equal to or less than the above upper limit, the brittleness of the toner is less likely to be lowered, the toner is less likely to be broken, and the toner is less likely to be crushed, so that the developability is improved. On the other hand, when the major axis or area of the domain A is equal to or more than the above lower limit, the releasing effect is sufficient and peeling hardly occurs.
The (r/R) of domain A is preferably 0.2 or more and 0.325 or less. The (r/R) of the domain A should be controlled by the amount of the release agent added, the cooling rate 1 of the step (i) described below, and the holding time of the step (ii) and the elapsed time of the step (b). You can
Further, SA is preferably 5% or more and 20% or less. SA can be controlled by the amount of the release agent added, the cooling rate 1 in step (i) described below, the holding time in step (ii) (a), and the elapsed time in step (b).

In the toner of the present invention, the (r/R) of domain B is 0.000625≦(r/R)≦0.0625. Within the above range, a large amount of melt deformation of the toner does not occur when heat is applied. When the (r/R) of the domain B is 0.000625 or more, the effect of the release agent of the domain A serving as a path for exuding the release agent at the time of heat melting is sufficiently exerted, and peeling is less likely to occur. On the other hand, when the (r/R) of the domain B is 0.0625 or less, the deformation of the toner by the release agent of the domain B is small at the time of fixing, and thus the crushing is less likely to occur. The (r/R) of domain B is preferably 0.01 or more and 0.052 or less. The (r/R) of the domain B can be controlled by the retention time of the step (ii) described later (a) or the elapsed time of (b) described later.
In the toner of the present invention, the area ratio SB of the domain B in the toner cross section is 0.1≦SB/SA≦0.8. When the ratio of the total area of the domain B is within this range, the domain A can quickly exude to the surface of the toner through the domain B during the heat melting. If the area ratio of the domain B to the area of the domain A is too small, the effect of the release agent of the domain A serving as a path through which the release agent oozes out cannot be sufficiently exhibited. Further, if the area ratio of the domain B to the area of the domain A is too large, the brittleness of the toner is lowered and the toner is easily broken. Further, the binder resin of the entire toner is softened at the time of fixing, and fine line collapse easily occurs.
SB/SA is preferably 0.1 or more and 0.6 or less. SB can be controlled by the type of the release agent, the cooling rate 1 in the step (i) described below, the holding time in the step (ii) and the elapsed time in the step (b).

In the present invention, the aspect ratio of the domain B in the toner cross section is 0.3 or less. The method of calculating the aspect ratio will be described later. The aspect ratio of domain B of 0.3 or less indicates that the shape of domain B is close to a needle shape. When the shape of the domain B is close to a needle shape, as described above, the domain B easily functions as a passage during heat melting, and the amount of release agent exposed can be increased while suppressing deformation of the toner. Here, when the aspect ratio of the domain B exceeds 0.3, the shape becomes close to a sphere, and the volume of the domain B increases, so that the toner is largely deformed during heat melting, and crushing easily occurs. Further, since the amount of the releasing agent exposed on the surface of the toner after being left in a harsh environment becomes large, the developability after being left in a harsh environment is deteriorated.
The aspect ratio is preferably 0.2 or less. The lower limit is not particularly limited, but is preferably 0.01 or more.

Hereinafter, preferred modes of the toner of the present invention will be described.
Examples of the release agent used in the present invention include the followings as examples of using known materials. Aliphatic hydrocarbon wax such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, Fischer-Tropsch wax, paraffin wax; oxide of aliphatic hydrocarbon wax such as oxidized polyethylene wax, or block copolymer thereof. Waxes containing fatty acid ester as a main component such as carnauba wax and montanic acid ester wax, and fatty acid ester such as deoxidized carnauba wax partially or wholly deoxidized; palmitic acid, stearic acid, montanic acid, etc. Unsaturated fatty acids such as brassic acid, eleostearic acid and parinaric acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubayl alcohol, ceryl alcohol and melysyl alcohol; sorbitol Such as polyhydric alcohols; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide, etc. Saturated fatty acid bisamides; unsaturated fatty acid amides such as ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N,N' dioleyl adipic acid amide, N, N'dioleyl sebacic acid amide; m-xylene bis stearin Aromatic bisamides such as acid amide and N,N' distearylisophthalic acid amide; Aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally called metallic soap); Waxes obtained by grafting aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid; partial esterification products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols; obtained by hydrogenation of vegetable oils and fats A methyl ester compound having a hydroxyl group.

Among these release agents, it is preferable to use hydrocarbon wax such as paraffin wax and Fischer-Tropsch wax. It is known that a hydrocarbon wax crystallizes in a form in which linear hydrocarbon chain portions are stacked. When the release agent has few constituents other than the hydrocarbon wax, the stacking is likely to occur only in a specific direction, and as a result, the domains are likely to be acicular.
In the present invention, a wax other than the hydrocarbon wax can be used in combination within a range that does not impair the effects of the present invention. In the present invention, in order to set the aspect ratio to 0.3 or less, for example, the amount of the hydrocarbon wax relative to the total amount of the release agent is set to 35% by mass or more, and the release agent is heated to a temperature of the melting point or higher in the manufacturing process. It is preferable to simultaneously satisfy the means such as crystal growth after the melting. The amount of the hydrocarbon wax relative to the total amount of the release agent is preferably 35% by mass or more and 100% by mass or less.

In the present invention, it is preferable that the domain A and the domain B are derived from the same release agent. Since the domain A and the domain B are derived from the same release agent, the affinity is increased, the domain B is more likely to function as a path for the domain A, and peeling is more easily suppressed. In the step (i) described later, by heating to a temperature equal to or higher than the melting point of all the release agents to be used, sufficiently melting all the release agents, and then cooling the same, the domain A and the domain B are the same. It may be derived from a release agent.

The release agent is preferably used in an amount of 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin or the polymerizable monomer constituting the binder resin.
Known waxes can be used as the other wax to be combined with the hydrocarbon wax. From the viewpoint of plasticizing ability to the binder resin, waxes having a fatty acid ester as a main component such as carnauba wax and montanic acid ester wax, and those obtained by deoxidizing a part or all of fatty acid esters such as deoxidized carnauba wax are recommended. It can be preferably used.

In the present invention, the proportion of the toner having the domain A of the release agent at the center point of the cross section of the toner is preferably 80 number% or more and 100 number% or less. More preferably, it is 90% by number or more and 100% by number or less. The presence of the domain A at the center point of the toner cross section reduces the variation in the distance from the domain A to the toner surface. As a result, the release agent bleeds uniformly in all directions during fixing, and the effect of the present invention is easily obtained.
In order for the release agent domain to exist at the center point of the toner cross section, it is preferable to control the acid value and the hydroxyl value of the release agent to low values. Further, in the manufacturing process of the toner, the binder resin and the release agent are simultaneously melted at a temperature equal to or higher than each melting point, and then cooling is performed, so that the release agent having a low acid value and a low hydroxyl value is provided near the center of the toner. It becomes easy to exist. Hereinafter, the ratio (number%) of the toner in which the domain A of the release agent exists at the center point of the toner cross section is also referred to as the center ratio.

In the toner of the present invention, the number of domains B in the toner cross section is preferably 5 or more and 500 or less, and more preferably 20 or more and 500 or less. When the number of the domains B is 5 or more, the domains B easily function as a passage during heat melting, and peeling and crushing are highly compatible.

In the present invention, the surface layer region within 1.0 μm from the surface of the toner in the toner cross section is E, the chord giving the maximum length of the toner cross section is the line segment C, passing through the midpoint of the line segment C, and When the chord orthogonal to the line segment C is a line segment D, and when the four regions formed by the line segment C, the line segment D, and the region E are W, X, Y, and Z, respectively. The coefficient of variation of the number of domains B existing in the regions W, X, Y, and Z is preferably 40% or less, and more preferably 35% or less. The lower limit is not particularly limited, but is preferably 0% or more. The coefficient of variation can be controlled by the temperature of T1 and the cooling rate 1 in step (i) described later.
In the present invention, in order to achieve both peeling and crushing, it is important that the number of domains B in the region near the toner surface has little unevenness. Further, since the domain B in which the release agent is crystallized is uniformly present in the vicinity of the surface layer of the toner, it is possible to prevent the external additive from being buried after being left in a harsh environment and improve the thinness of the concentration. Therefore, when the coefficient of variation satisfies the above range, peeling, crushing, heat resistant storage, and all the problems can be achieved at the same time. In the present invention, the coefficient of variation of the number of domains B existing in the four regions W, X, Y, and Z within 1.0 μm from the toner surface is also referred to as a surface layer domain coefficient of variation hereinafter.

Examples of the colorant used in the present invention include the following organic pigments, organic dyes, and inorganic pigments.
Examples of cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specifically, the following are mentioned. C. I. Pigment Blue 1, C.I. I. Pigment Blue 7, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15:1, C.I. I. Pigment Blue 15:2, C.I. I. Pigment Blue 15:3, C.I. I. Pigment Blue 15:4, C.I. I. Pigment Blue 60, C.I. I. Pigment Blue 62, and C.I. I. Pigment Blue 66.
Examples of magenta colorants include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, the following are mentioned. C. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Violet 19, C.I. I. Pigment Red 23, C.I. I. Pigment Red 48:2, C.I. I. Pigment Red 48:3, C.I. I. Pigment Red 48:4, C.I. I. Pigment Red 57:1, C.I. I. Pigment Red 81:1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 144, C.I. I. Pigment Red 146, C.I. I. Pigment Red 150, C.I. I. Pigment Red 166, C.I. I. Pigment Red 169, C.I. I. Pigment Red 177, C.I. I. Pigment Red 184, C.I. I. Pigment Red 185, C.I. I. Pigment Red 202, C.I. I. Pigment Red 206, C.I. I. Pigment Red 220, C.I. I. Pigment Red 221 and C.I. I. Pigment Red 254.

Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, the following are mentioned. C. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 62, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 83, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 95, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 109, C.I. I. Pigment Yellow 110, C.I. I. Pigment Yellow 111, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 127, C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 129, C.I. I. Pigment Yellow 147, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 154, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 168, C.I. I. Pigment Yellow 174, C.I. I. Pigment Yellow 175, C.I. I. Pigment Yellow 176, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 181, C.I. I. Pigment Yellow 185, C.I. I. Pigment Yellow 191, and C.I. I. Pigment Yellow 194.
Examples of the black colorant include carbon black, and the above yellow-based colorant, magenta-based colorant, cyan-based colorant, and magnetic powder toned black.
These colorants may be used alone or in combination, and may be used in the form of a solid solution. The colorant used in the present invention is selected in terms of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner.

When a magnetic powder is used as the colorant in the toner of the present invention, the magnetic powder may be triiron tetraoxide or γ-
It is mainly composed of magnetic iron oxide such as iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. These magnetic powders preferably have a BET specific surface area of ² to 30 m ² /g by a nitrogen adsorption method, and 3 to ²
It is more preferably 8 m ² /g. Moreover, it is preferable that the Mohs hardness is 5 to 7. The shape of the magnetic powder may be a polyhedron, an octahedron, a hexahedron, a sphere, a needle, a scale, or the like. It is preferable in order to raise it.

The magnetic powder preferably has a number average particle size of 0.10 to 0.40 μm. Generally, the smaller the particle size of the magnetic powder, the higher the coloring power, but the above range is preferable from the viewpoint of aggregation of the magnetic powder. Further, when the number average particle size is 0.10 μm or more and the magnetic powder itself is less likely to become reddish black, redness is not noticeable especially in a halftone image, and a high quality image can be obtained. On the other hand, when the number average particle diameter is 0.40 μm or less, the coloring power of the toner is improved, and uniform dispersion is easy in the suspension polymerization method (described later).
The number average particle diameter of the magnetic powder can be measured using a transmission electron microscope. Specifically, the toner to be observed is sufficiently dispersed in the epoxy resin and then cured in an atmosphere at a temperature of 40° C. for 2 days to obtain a cured product. The obtained cured product is used as a flaky sample with a microtome, and 100 particles of magnetic powder in the visual field are measured with a transmission electron microscope (TEM) at a magnification of 10,000 to 40,000 times. Then, the number average particle diameter is calculated based on the equivalent diameter of a circle equal to the projected area of the magnetic powder. It is also possible to measure the particle size with an image analysis device.

The magnetic powder used in the toner of the present invention can be produced, for example, by the following method. An aqueous solution containing ferrous hydroxide is prepared by adding an equivalent amount or an equivalent amount or more of an alkali such as sodium hydroxide to an aqueous ferrous salt solution. Air is blown while maintaining the pH of the prepared aqueous solution at pH 7 or higher, and the oxidation reaction of ferrous hydroxide is carried out while heating the aqueous solution to 70° C. or higher, and seed crystals that form the core of the magnetic iron oxide powder are first prepared. To generate.
Next, an aqueous solution containing about 1 equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals based on the amount of alkali added previously. While maintaining the pH of the solution at 5 to 10, the reaction of ferrous hydroxide is advanced while blowing air, and the magnetic iron oxide powder is grown with the seed crystal as the core. At this time, the shape and magnetic properties of the magnetic powder can be controlled by selecting an arbitrary pH, reaction temperature, and stirring conditions. The pH of the liquid shifts to the acidic side as the oxidation reaction proceeds, but it is preferable that the pH of the liquid is not less than 5. The magnetic powder thus obtained can be obtained by filtering, washing and drying the magnetic substance by a conventional method.

Further, in the present invention, when the toner is produced in the aqueous medium, it is very preferable to make the surface of the magnetic powder hydrophobic. When dry surface treatment is performed, the washed, filtered and dried magnetic powder is treated with a coupling agent. When the surface treatment is carried out by a wet method, after the completion of the oxidation reaction, the dried product is redispersed, or after the completion of the oxidation reaction, the iron oxide obtained by washing and filtration is dried in another aqueous medium. And re-dispersed in the solution to perform coupling treatment. In the present invention, either the dry method or the wet method can be appropriately selected.

Examples of the coupling agent that can be used in the surface treatment of the magnetic powder of the present invention include silane coupling agents and titanium coupling agents. A silane coupling agent is more preferably used and is represented by the general formula (I).
R _m SiY _n (I)
[In the formula, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a functional group such as an alkyl group, a phenyl group, a vinyl group, an epoxy group, a (meth)acryl group, and n is 1 Indicates an integer of ˜3. However, m+n=4. ]

Examples of the silane coupling agent represented by the general formula (I) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, Vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, n-propyltrimethoxysilane, Isopropyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, trimethylmethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, hydroxy Examples thereof include propyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane and the like. In the present invention, those in which Y in the general formula (I) is an alkyl group can be preferably used. Among them, an alkyl group having 3 to 6 carbon atoms is preferable, and 3 or 4 is particularly preferable.

When the silane coupling agent is used, it can be treated alone or in combination of two or more types. When a plurality of types are used in combination, each coupling agent may be treated individually or simultaneously.
The total treatment amount of the coupling agent used is preferably 0.9 to 3.0 parts by mass with respect to 100 parts by mass of the magnetic powder, and the treatment is performed depending on the surface area of the magnetic powder, the reactivity of the coupling agent and the like. It is important to adjust the amount of agent.
The addition amount of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin or the polymerizable monomer constituting the binder resin. When the magnetic powder is used, it is preferably 20 parts by mass or more and 200 parts by mass or less, more preferably 40 parts by mass or more and 150 parts by mass with respect to 100 parts by mass of the binder resin or the polymerizable monomer constituting the binder resin. It is below.

Examples of the binder resin used in the toner of the present invention include homopolymers of styrene such as polystyrene and polyvinyltoluene and substitution products thereof; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers. Coal, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene -Methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene -Styrene such as vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer -Based copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin can be used, and these can be used alone. Alternatively, a plurality of types can be used in combination. Among these, styrene-acrylic resins represented by styrene-butyl acrylate are particularly preferable in terms of developing characteristics, fixing properties and the like.

In the present invention, the binder resin preferably contains styrene acrylic resin as a main component. Since the styrene acrylic resin is less compatible with the release agent than the polyester resin, it is easy to form the domain of the release agent in the binder resin, the amount of the compatible release agent is reduced, and the effect of the present invention is obtained. It can be increased. The preferable content of the styrene acrylic resin with respect to the binder resin is 80% by mass or more and 100% by mass or less.

The following can be illustrated as a polymerizable monomer which forms the said styrene acrylic resin.
Examples of the styrene-based polymerizable monomer include styrene; styrene-based polymerizable monomers such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-ethylstyrene. Is mentioned.
Acrylic polymerizable monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate. And acrylic polymerizable monomers such as n-octyl acrylate, dodecyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, cyclohexyl acrylate, and phenyl acrylate.
Examples of the methacrylic polymerizable monomer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, dodecyl methacrylate, 2 Examples thereof include methacrylic polymerizable monomers such as ethylhexyl methacrylate, stearyl methacrylate, n-octyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate.
Other monomers such as acrylonitrile, methacrylonitrile, acrylamide and the like can be mentioned.
The method for producing the styrene acrylic resin is not particularly limited, and a known method can be used. The binder resin may be used in combination with other known resins.

The toner of the present invention may use a charge control agent in order to keep the chargeability of the toner stable regardless of the environment.
Examples of the negatively chargeable charge control agent include the following. Monoazo metal compound, acetylacetone metal compound, aromatic oxycarboxylic acid, aromatic dicarboxylic acid, oxycarboxylic acid and dicarboxylic acid type metal compound, aromatic oxycarboxylic acid, aromatic mono- and polycarboxylic acid and metal salt thereof, Examples thereof include anhydrides, esters, phenol derivatives such as bisphenol, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, and resin-based charge control agents.
Examples of the positively chargeable charge control agent include the following. Nigrosine modified products with nigrosine and fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs thereof Onium salts such as phosphonium salts and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid) Acids, ferricyanides, ferrocyanides, etc.); metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotins such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate. Tin borates; resin type charge control agents can be mentioned.

These can be used alone or in combination of two or more.
Among them, as the charge control agent other than the resin-based charge control agent, a metal-containing salicylic acid-based compound is preferable, and one whose metal is aluminum or zirconium is more preferable. A more preferable control agent is an aluminum salicylate compound.
As the resin-based charge control agent, it is preferable to use a polymer or copolymer having a sulfonic acid group, a sulfonic acid group or a sulfonic acid ester group, a salicylic acid moiety, and a benzoic acid moiety.
The compounding amount of the charge control agent is preferably 0.01 parts by mass or more and 20.0 parts by mass or less, more preferably 0.05 parts by mass or more and 10.0 parts by mass with respect to 100.0 parts by mass of the polymerizable monomer. Below the section.

The weight average particle diameter (D4) of the toner produced by the present invention is preferably 3.0 μm or more and 12.0 μm or less, and more preferably 4.0 μm or more and 10.0 μm or less. When the weight average particle diameter (D4) is 3.0 μm or more and 12.0 μm or less, good fluidity is obtained, and the latent image can be faithfully developed.

The toner of the present invention can be manufactured by various known methods. In order to control the existence state of the domain, it is preferable to perform the process described below during the production.
First, in the case of manufacturing by a pulverization method, for example, a binder resin, a colorant, a release agent, and if necessary, a crystalline substance, an additive such as a charge control agent, etc. are sufficiently mixed in a mixer such as a Henschel mixer or a ball mill. Mix. After that, the toner material is melt-kneaded by using a heat kneader such as a heating roll, a kneader, or an extruder to disperse or dissolve the toner material, and after cooling and solidifying and pulverizing, classification, and if necessary, surface treatment is performed to obtain toner particles. Obtainable. Either the classification or the surface treatment may be performed first. In terms of production efficiency, it is preferable to use a multi-division classifier in the classification step.

The crushing step can be performed by a method using a known crushing device such as a mechanical impact type and a jet type. Further, it is preferable to further apply heat to carry out pulverization, or to carry out a treatment to supplementarily apply mechanical impact. Further, a hot water bath method in which finely pulverized toner particles (classified as necessary) are dispersed in hot water, a method of passing through a hot air stream, or the like may be used.

Means for applying a mechanical impact force include, for example, a method using a mechanical impact type crusher such as Kawasaki Heavy Industries Co., Ltd.'s Kryptron system or Turbo Kogyo's turbo mill. Also, like devices such as Hosokawa Micron's Mechano-Fusion System and Nara Machinery's Hybridization System, etc., the toner is pressed against the inside of the casing by centrifugal force with high-speed rotating blades, and the force such as compression force and friction force is applied. A method of applying a mechanical impact force to the toner can be mentioned.

When toner particles are produced by a dry method such as a pulverization step, in order to obtain the effects of the present invention, it is preferable to disperse the toner particles in an aqueous medium and perform a specific treatment step including a cooling step described later. .. At that time, as described below, a surfactant, an organic dispersant or an inorganic dispersant known as a dispersant can be used so that the toner particles do not easily coalesce when they are heated in an aqueous medium. Among them, the poorly water-soluble inorganic dispersant is less likely to produce harmful ultrafine powder, and has stable dispersion due to its steric hindrance. Therefore, stability is not easily deteriorated even when the reaction temperature is changed, and cleaning is easy and a toner is obtained. Since it is difficult to give an adverse effect, it can be preferably used. Further, the poorly water-soluble inorganic dispersant is highly preferable because it has high polarity and easily suppresses the deposition of the hydrophobic release agent on the surface of the toner particles.

The preferred production method of the present invention is a production method of obtaining toner particles by a suspension polymerization method. In the suspension polymerization method, the toner particles are manufactured in an aqueous medium, and the crystallization of the release agent is easily controlled, so that the suspension polymerization method is easily incorporated into the manufacturing process. According to this manufacturing method, a toner having a sharp particle size distribution and a high degree of circularity can be obtained, and a toner having a core-shell structure can be easily formed. Therefore, the effect of the present invention can be further enhanced.

When manufactured by the emulsion aggregation method, the release agent domains are easily dispersed throughout the toner. When manufactured by the emulsion aggregation method, in order to control the position where the domain is present, it is preferable to perform the aggregation of the release agent fine particles in plural times.

The suspension polymerization method will be described below.
The suspension polymerization method is to uniformly disperse the polymerizable monomer constituting the binder resin, the release agent and the colorant (further, if necessary, a polymerization initiator, a crosslinking agent, a charge control agent and other additives). A polymerizable monomer composition is obtained by dissolving or dispersing. Then, this polymerizable monomer composition is dispersed and granulated in a continuous layer (for example, an aqueous phase) containing a dispersant using a suitable stirrer. Then, the polymerizable monomer contained in the multi-layered monomer composition is polymerized to obtain a toner having a desired particle size. The toner obtained by this suspension polymerization method (hereinafter also referred to as “polymerized toner”) has a substantially spherical shape of each individual toner particle, and therefore the distribution of the charge amount is relatively uniform, which improves the image quality. Can be expected.
In the production of the polymerized toner according to the present invention, examples of the polymerizable monomer forming the polymerizable monomer composition include the above-mentioned polymerizable monomers forming a styrene acrylic resin. Above all, it is preferable to use styrene alone or in a mixture with other monomers, from the viewpoint of developing characteristics and durability of the toner.

The polymerization initiator used in the production of the toner of the present invention by the polymerization method is preferably one having a half-life in the polymerization reaction of 0.5 to 30 hours. Further, when the polymerization reaction is performed using an addition amount of 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer, a polymer having a maximum between molecular weights of 5,000 and 50,000 can be obtained. It can give the toner the desired strength and proper melting characteristics.

Specific examples of the polymerization initiator include 2,2′-azobis-(2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis(cyclohexane-1- Carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and other azo or diazo polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxide Peroxide type polymerization initiators such as oxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, t-butylperoxy 2-ethylhexanoate, t-butylperoxypivalate Can be mentioned.

When the toner of the present invention is produced by a polymerization method, a crosslinking agent may be added, and the preferable addition amount is 0.1 parts by mass or more and 10.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer. It is below.
As the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol diethylene. Carboxylic acid ester having two double bonds such as methacrylate and 1,3-butanediol dimethacrylate; divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and having 3 or more vinyl groups The compound; is used alone or as a mixture of two or more kinds.

In the method for producing the toner of the present invention by a polymerization method, generally, the above-mentioned toner composition and the like are appropriately added, and a polymerizable monodisperse product which is uniformly dissolved or dispersed by a homogenizer, a ball mill, a disperser such as an ultrasonic disperser is used. The monomer composition is suspended in an aqueous medium containing a dispersant. At this time, the particle size of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to make the desired toner particle size at a stretch. Regarding the timing of addition of the polymerization initiator, it may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or a solvent may be added immediately after granulation and before starting the polymerization reaction.
After the granulation, an ordinary stirrer may be used to stir the particles so that the particle state is maintained and the particles are prevented from floating and settling.

In the case of producing the toner of the present invention, known dispersants such as a surfactant, an organic dispersant, and a poorly water-soluble inorganic dispersant can be used. Among them, the poorly water-soluble inorganic dispersant is unlikely to produce harmful ultrafine powder, and has stable dispersion due to its steric hindrance. Since it is difficult to give an adverse effect, it can be preferably used. Furthermore, a poorly water-soluble inorganic dispersant is highly preferable because it has high polarity and tends to suppress the deposition of a hydrophobic release agent on the surface of toner particles.
Examples of such inorganic dispersants include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, polyvalent metal phosphates such as hydroxyapatite, calcium carbonate, carbonates such as magnesium carbonate, calcium metasilicate, calcium sulfate, Examples thereof include inorganic salts such as barium sulfate, and inorganic compounds such as calcium hydroxide, magnesium hydroxide and aluminum hydroxide.
These inorganic dispersants are preferably used in an amount of 0.2 parts by mass or more and 20.0 parts by mass or less based on 100 parts by mass of the polymerizable monomer.

When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, it is preferable to generate and use the inorganic dispersant particles in an aqueous medium. For example, in the case of tricalcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution can be mixed under high-speed stirring to generate water-insoluble calcium phosphate, which enables more uniform and fine dispersion. At this time, a water-soluble sodium chloride salt is produced as a by-product at the same time, but when the water-soluble salt is present in the aqueous medium, the dissolution of the polymerizable monomer in water is suppressed, and ultrafine toner particles are generated by emulsion polymerization. It is difficult to do so, so it is preferable.
Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.
In the step of polymerizing the polymerizable monomer, the polymerization temperature is usually set to 40°C or higher, preferably 50 to 100°C.

Below, the processing process (cooling process) suitable for this invention is described.
The following steps (i) and (ii) are preferably performed after the toner particles are manufactured. For example, in the case of the suspension polymerization method described later, it is preferable to carry out the steps (i) and (ii) after the polymerization reaction of the polymerizable monomer.
In the step (i), the temperature of the aqueous medium in which the toner particles are dispersed is higher than the higher one of the crystallization temperature Tc (° C.) of the release agent and the glass transition temperature Tg (° C.) of the toner particles. (
This is a step of cooling from Tc (° C.) and a temperature higher than Tg (° C.)) to a temperature below the Tg (° C.) at a cooling rate of 5.00° C./min or more.
In the suspension polymerization method, the polymerization temperature for polymerizing the polymerizable monomer is either the crystallization temperature Tc (° C.) of the release agent or the glass transition temperature Tg (° C.) of the toner particles in step (i). When the temperature is higher than the temperature, it is not necessary to further heat the aqueous medium. On the other hand, when the temperature of the aqueous medium is lower than the above temperature, it is preferable to raise the temperature of the aqueous medium so as to satisfy the temperature.
In the step (i), first, in order to sufficiently melt both the binder resin and the release agent, the temperature of the aqueous medium is 30 minutes or more and 600 minutes or less, and the crystallization temperature Tc (° C.) of the release agent and It is preferable to maintain the temperature so that it is higher than the glass transition temperature Tg (° C.) of the toner particles.
By maintaining the high temperature state for 30 minutes or more, it becomes easy to obtain a toner having a center ratio of 80% or more.

Subsequently, the temperature of the aqueous medium is lowered to the glass transition temperature Tg (° C.) of the toner particles or lower at a cooling rate of 5
． Cool rapidly at a rate of 00°C/min or more. Here, the cooling start temperature T1 is a temperature at which the temperature of the aqueous medium is higher than the crystallization temperature Tc (° C.) of the release agent and the glass transition temperature Tg (° C.) of the toner particles, and the temperature immediately before the rapid cooling. Is. Subsequently, the cooling stop temperature T2 is the temperature of the aqueous medium when the operation of rapidly cooling is completed. The cooling rate 1 of the aqueous medium in the step (i) is calculated by the following formula.
Cooling rate 1=(T1(° C.)−T2(° C.))/time required for cooling (min)

As means for rapidly cooling the temperature of the aqueous medium, for example, an operation of mixing cold water or ice, an operation of bubbling the aqueous medium with cold air, an operation of removing heat of the aqueous medium using a heat exchanger, etc. should be used. Is possible.
In the present invention, the above cooling rate is preferably 5.00° C./minute or more. When the cooling rate is 5.00° C./min or more, in the step (ii) described later, the number of domains B of the release agent is increased, and the fixability of the obtained toner and the developability after being left in a harsh environment. Will be good. A preferable cooling rate range is 55.00° C./min or more, and a more preferable range is 95.00° C./min or more. The upper limit is not particularly limited, but preferably 3000° C./min or less. By cooling in these ranges, the number of domains B generated can be further increased.

In the step (i), the crystallization temperature Tc (°C) is preferably higher than the glass transition temperature Tg (°C) by 10°C or more. Further, the step (i) is preferably a step of cooling from a temperature 5 to 22° C. higher than the crystallization temperature Tc (° C.) to a temperature not higher than the Tg (° C.) at a cooling rate of 5.00° C./min or higher. .. As described above, when the cooling start temperature T1 is higher than the crystallization temperature Tc (° C.) by 5 to 22° C., it becomes easy to control the dispersion state of the release agent in the toner particles, and the fixing property and the development after standing in a harsh environment are performed. It becomes even better.

Then, in step (ii),
(A) a step of holding the aqueous medium that has undergone the step (i) in the temperature range of the glass transition temperature Tg±10° C. of the toner particles for 30 minutes or more, or
(B) A step of cooling the aqueous medium that has undergone the step (i) so that the glass transition temperature Tg of the toner particles Tg±10° C. is maintained for 20 minutes or more.
In the step (ii), the crystallinity of the releasing agent is improved and crystallinity is improved by crystal growth inside the toner particles. Generation of crystal nuclei and crystal growth proceed favorably in the above temperature range with respect to the glass transition temperature Tg of the toner particles.

In (a) of the step (ii), the temperature of the aqueous medium is kept constant at an arbitrary temperature in the above-mentioned temperature range, and crystal growth is performed. The time for maintaining the temperature of the aqueous medium is preferably 30 minutes or more for sufficient crystal growth. It is more preferably 90 minutes or longer, and even more preferably 120 minutes or longer. On the other hand, the upper limit is preferably 600 minutes or less. When the cooling stop temperature T2 is lower than the above temperature range, the aqueous medium may be heated again to the above temperature range, and then the temperature may be maintained.

By holding at Tg −10° C. or higher, the binder resin is not excessively solidified, and thus the domain B easily crystallizes. Further, by holding at Tg+10° C. or lower, the binder resin is appropriately solidified, and the release agent compatible with the binder resin easily forms the domain B.

In step (ii) (b), when the time of the temperature of the aqueous medium is in the above-mentioned temperature range is the elapsed time, the elapsed time is set to 20 minutes or more to perform crystal growth. A preferred range of the elapsed time is 40 minutes or longer, and a more preferred range is 100 minutes or longer. On the other hand, the upper limit is preferably 600 minutes or less. After the temperature of the water-based medium is out of the range of the above temperature range, by heating or cooling the water-based medium, if the temperature of the water-based medium is within the range of the above temperature range multiple times, the cumulative cooling time is the elapsed time. And When the elapsed time is 20 minutes or more, crystal growth will be sufficient, and fixability and developability will be good.

When the cooling start temperature is T3 and the cooling stop temperature is Tg-10° C. in (ii) step (b), the cooling rate 2 in (ii) step (b) can be obtained from the following equation. it can.
Cooling rate 2 = (T3 (°C)-(Tg-10°C))/elapsed time (minutes)

In the present invention, the ratio of the cooling rate 2 to the cooling rate 1 is preferably 0.05 or less. In this range, the release agent compatible with the binder resin during the cooling of the step (i) forms a large number of crystal nuclei in the step (ii), so that the number of domains B increases and Crystal growth. Therefore, the fixability and the developability after being left in a harsh environment are improved, which is preferable. A more preferable range is 0.02 or less.

The toner particles after cooling are filtered, washed and dried by a known method to obtain the toner particles as a powder. It is also possible to obtain a toner by mixing the toner particles with an inorganic fine powder as described below and adhering the mixture to the surface of the toner particles. It is also possible to insert a classification step in the manufacturing step (before mixing the inorganic fine powder) to cut coarse powder or fine powder contained in the toner particles.

If necessary, additives such as a fluidizing agent may be mixed with the toner particles obtained by the above-described manufacturing method to obtain a toner. Regarding the mixing method, a known method can be used, and for example, a Henschel mixer is a device that can be suitably used.
In the toner of the present invention, it is a preferred embodiment that an inorganic fine powder having a number average primary particle diameter of 4 to 80 nm, more preferably 6 to 40 nm is added to the toner particles as a fluidizing agent. The inorganic fine powder is added to improve the fluidity of the toner and to make the toner particles evenly charged, but the inorganic fine powder is subjected to a treatment such as a hydrophobic treatment to adjust the toner charge amount and improve the environmental stability. It is also a preferable form to impart the function of. The number average primary particle diameter of the inorganic fine powder is measured by using a photograph of the toner magnified by a scanning electron microscope.

As the inorganic fine powder used in the present invention, silica, titanium oxide, alumina or the like can be used. As the silica fine powder, for example, both a so-called dry method produced by vapor phase oxidation of a silicon halide or a dry silica referred to as fumed silica, and a so-called wet silica produced from water glass or the like can be used. is there. However, dry silica having less silanol groups on the surface and inside the fine silica powder and less production residues such as Na ₂ O and SO ₃ ^2- is preferable. Further, in the case of dry silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halogen compound such as aluminum chloride and titanium chloride together with a silicon halogen compound in the manufacturing process, They are also included.
The addition amount of the inorganic fine powder is preferably 0.1 part by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the toner particles. If the addition amount is 0.1 parts by mass or more, the effect will be sufficient, and if it is 3.0 parts by mass or less, the fixability will be good. The content of the inorganic fine powder can be quantified using fluorescent X-ray analysis and a calibration curve prepared from a standard sample.

In the present invention, the inorganic fine powder is preferably hydrophobized from the viewpoint of improving the environmental stability of the toner. The hydrophobic treatment makes it difficult for the inorganic fine powder added to the toner to absorb moisture, stabilize the charge amount of the toner particles, and prevent toner scattering. As the treatment agent used for the hydrophobic treatment of the inorganic fine powder, silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oil, silane compounds, silane coupling agents,
Other treating agents such as organic silicon compounds and organic titanium compounds may be used alone or in combination of two or more.

Next, an example of an image forming apparatus that can suitably use the toner of the present invention will be specifically described with reference to FIG. In FIG. 2, reference numeral 100 denotes a photoconductor, around which a charging roller 117, a developing device 140 having a toner carrier 102, a transfer charging roller 114, a cleaner 116, a pickup roller 124, etc. are provided. The photoreceptor 100 is charged to, for example, −600 V by the charging roller 117 (applied voltage is, for example, AC voltage 1.85 kVpp, DC voltage −620 Vdc). Then, the laser light generator 121 irradiates the photoconductor 100 with laser light 123 to perform exposure, and an electrostatic latent image corresponding to a target image is formed. The electrostatic latent image on the photoconductor 100 is developed with a one-component toner by the developing device 140 to obtain a toner image, and the toner image is transferred onto the transfer material by the transfer charging roller 114 abutting on the photoconductor via the transfer material. Transcribed. The transfer material on which the toner image is placed is conveyed to the fixing device 126 by the conveyor belt 125 or the like and fixed on the transfer material. The toner left on the photosensitive member is partially cleaned by the cleaner 116.
Although an image forming apparatus for magnetic one-component jumping development is shown here, it may be used for any method of jumping development or contact development.

Next, methods for measuring various physical properties relating to the production of the toner of the present invention will be described.
<Measurement method of weight average particle diameter (D4) of toner>
The weight average particle diameter (D4) of the toner is calculated as follows (the same is true for toner particles). As a measuring device, a precision particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube by a pore electrical resistance method is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with the number of effective measurement channels of 25,000.
The electrolytic aqueous solution used for the measurement may be prepared by dissolving special grade sodium chloride in ion-exchanged water so that the concentration becomes about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.).
Before measuring and analyzing, set the dedicated software as follows.
On the "Change standard measurement method (SOM)" screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to "standard particles 10.0 μm" (Beckman Coulter, Inc.). The value obtained by using the product is set. The threshold and noise level are automatically set by pressing the "Threshold/noise level measurement button". Further, the current is set to 1600 μA, the gain is set to 2, and the electrolytic solution is set to ISOTON II, and a check is put in “Flash of aperture tube after measurement”.
On the "Pulse to particle size conversion setting" screen of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bin, and the particle size range from 2 μm to 60 μm.

The specific measuring method is as follows.
(1) About 200 ml of the electrolytic aqueous solution was placed in a glass 250 ml round-bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod was stirred counterclockwise at 24 rpm. Then, the dirt and air bubbles in the aperture tube are removed by the "aperture flush" function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is placed in a glass 100 ml flat-bottom beaker. In this, as a dispersant, "contaminone N" (a nonionic surfactant, an anionic surfactant, a 10 mass% aqueous solution of a neutral detergent for washing precision measuring instruments of pH 7 comprising an organic builder, manufactured by Wako Pure Chemical Industries, Ltd. ) Is diluted about 3 times by mass with ion-exchanged water, and about 0.3 ml of a diluted solution is added.
(3) An ultrasonic disperser “Ultrasonic Dispersion System Tetra 150” (manufactured by Nikkaki Bios Co., Ltd.) having an electric output of 120 W is prepared by incorporating two oscillators having an oscillating frequency of 50 kHz with their phases shifted by 180 degrees. About 3.3 liters of ion-exchanged water is put in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to this water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the electrolytic aqueous solution in the beaker becomes maximum.
(5) About 10 mg of the toner is added little by little to the electrolytic aqueous solution in a state where the electrolytic aqueous solution in the beaker of the above (4) is irradiated with ultrasonic waves and dispersed. Then, the ultrasonic dispersion treatment is continued for another 60 seconds. In the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be 10°C or higher and 40°C or lower.
(6) To the round-bottom beaker of (1) installed in the sample stand, the electrolytic solution of (5) in which the toner is dispersed is dropped using a pipette, and the concentration is adjusted to about 5%. . Then, the measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed by the dedicated software attached to the apparatus to calculate the weight average particle diameter (D4). The "average diameter" on the "Analysis/volume statistical value (arithmetic mean)" screen when the graph/volume% is set with the dedicated software is the weight average particle diameter (D4).

<Observation Method of Toner Section in Scanning Transmission Electron Microscope (STEM) Dyeed with Ruthenium>
Cross-sectional observation of the toner with a scanning transmission electron microscope (STEM) can be carried out as follows.
The toner cross section is observed by ruthenium dyeing the toner cross section. Since the release agent contained in the toner of the present invention is dyed with ruthenium more than amorphous resin such as binder resin, the contrast becomes clear and the observation becomes easy. Since the amount of ruthenium atoms varies depending on the strength of staining, the strongly stained portion has many of these atoms, the electron beam does not penetrate, and the portion that is stained weakly becomes black on the observed image. The electron beam is easily transmitted and becomes white on the observed image.
First, the toner is sprinkled on the cover glass (Matsunami Glass Co., Ltd., square cover glass No. 1) so as to form a single layer, and an Os film is formed on the toner as a protective film using an osmium plasma coater (filgen company, OPC80T). (5 nm) and naphthalene film (20 nm). Next, a PTFE tube (Φ1.5 mm × Φ3 mm × 3 mm) is filled with photo-curing resin D800 (JEOL Ltd.), and the cover glass is placed on the tube so that the toner contacts the photo-curing resin D800. Place it gently in the facing direction. After the resin is cured by irradiating light in this state, the cover glass and the tube are removed to form a cylindrical resin in which the toner is embedded on the outermost surface. Ultrasonic Ultra Microtome (Leica
Company, UC7), at a cutting speed of 0.6 mm/s, the length of the radius of the toner (4.0 μm when the weight average particle diameter (D4) is 8.0 μm) is cut from the outermost surface of the cylindrical resin, Take out the cross section of the toner. Next, cutting was performed so as to have a film thickness of 250 nm, and a thin sample of a toner cross section was prepared. By cutting with such a method, a cross section of the toner central portion can be obtained.
The obtained thin section sample was dyed for 15 minutes in an atmosphere of 500 Pa of RuO ₄ gas using a vacuum electron dyeing device (VSC4R1H, manufactured by filgen), and STE was used by using the STEM function of TEM (JEOL, JEM2800).
M observation was performed.
Images were acquired with a STEM probe size of 1 nm and an image size of 1024×1024 pixels. Further, the image was acquired by adjusting Contrast of the Detector Control panel of the bright field image to 1425, Brightness to 3750, Contrast of the Image Control panel to 0.0, Brightness to 0.5, and Gammma to 1.00.

<Identification of release agent domain>
The domain of the release agent is identified based on the STEM image of the cross section of the toner by the following procedure.
When a release agent is available as a raw material, its crystal structure is observed in the same manner as the observation method of the toner cross section in the above-mentioned ruthenium-dyed scanning transmission electron microscope (STEM), and the lamella structure of the crystal of the raw material is observed. Get an image of. By comparing them with the lamella structure of the domain in the cross section of the toner, the raw material forming the domain in the cross section of the toner can be specified when the layer spacing of the lamella has an error of 10% or less.

<Isolation of release agent>
When the release agent raw material is not available, the isolation work is performed as follows. First, the toner is dispersed in ethanol, which is a poor solvent for the toner, and the temperature is raised to a temperature exceeding the melting point of the release agent. At this time, pressure may be applied if necessary. At this point, the release agent having a temperature above the melting point is melted. After that, by performing solid-liquid separation, the release agent mixture can be collected from the toner. The release agent can be isolated by separating this mixture by molecular weight.

<Measurement of major axis R of toner and major axis/minor axis of release agent domain>
Based on the STEM image obtained by observing the cross section of the toner with a scanning transmission electron microscope (STEM) subjected to ruthenium dyeing, 0.9≦R/D4≦1 with respect to the weight average particle diameter (D4) of the toner. In the cross section of the toner exhibiting the major axis R (μm) satisfying the relationship of 0.1, the major axis and the minor axis of the release agent domain are measured as follows.
First, the major axis R of the toner is measured on the cross section of the toner selected as described above. The arithmetic mean value of the major axis R of 100 cross sections is calculated.

<Measurement of major axis of domains A and B of release agent and respective (r/R)>
In the present invention, the major axes of domains A and B of the release agent are measured as follows.
The major axis of the release agent domain is measured based on the STEM image obtained by observing the cross section of the toner with a scanning transmission electron microscope (STEM) subjected to ruthenium dyeing treatment. At that time, cross sections of 100 or more toners are observed. The toner cross section used for the measurement has a major axis R (μm) satisfying the relationship of 0.9≦R/D4≦1.1 with respect to the weight average particle diameter (D4).
First, the major axis r (μm) of all domains is measured for one toner cross section. With respect to the major axis R (μm) of the one toner cross section, 0.125≦(r/R)≦0.375 is defined as the domain A, and 0.000625≦(r/R)≦0.0625. Let things be domain B. This is performed for 100 or more toners, and the arithmetic average value of each of the 100 or more toners is set as the average value of (r/R) of domain A and the average value of (r/R) of domain B.

<Measurement of average aspect ratio of domain B of release agent>
In the present invention, the aspect ratio of the domain B of the release agent is an aspect ratio (minor axis/major axis) indicated by a value obtained by dividing the minor axis of the domain B of the releasing agent by the major axis based on the STEM image. means.
The aspect ratio is calculated from the major axis and the minor axis of the domain B based on the STEM image obtained by observing the cross section of the toner with a scanning transmission electron microscope (STEM) that has been subjected to ruthenium dyeing, and the arithmetic mean thereof is measured. . At that time, cross sections of 100 or more toners are observed. All domains B are measured and the arithmetic average aspect ratio is calculated. The obtained arithmetic average aspect ratio is used as the aspect ratio of the domain B of the release agent.

<Measurement of the number of domain B of the release agent>
Similar to the measurement of the aspect ratio of the release agent domain B, the number of release agent domains B contained in each toner cross section is measured. This is performed for 100 or more toner cross sections, and the number of domains B per toner cross section is defined as the number of release agent domains B.

<Measurement of Area Ratio (SA and SB) of Release Agent Domain>
Based on the image obtained by the above STEM observation, the area of the release agent in the toner cross section is calculated using image processing software. The area is calculated for each of the domain A and the domain B, and when there are a plurality of release agent domains, the areas are accumulated. This is done for 100 or more toner cross sections. The area ratio of the domain A and the domain B of the release agent per one toner cross section is calculated by the following formula, and the average value of the area ratio of 100 or more toner cross sections is SA and SB.
Area ratio of release agent domain A (SA)=“total area of release agent domain A”/“area of toner cross section”×100 (area %)
Area ratio of domain B of release agent (SB)=“total area of domain B of release agent”/“area of toner cross section”×100 (area %)

<Measurement of surface domain variation coefficient>
The method of calculating the surface layer variation coefficient is as follows.
In the STEM image of the toner cross section, the surface layer region within 1.0 μm from the toner surface is E, the chord giving the maximum length of the toner cross section is a line segment C, and the line passing through the midpoint of the line segment C When the chord orthogonal to the segment C is a line segment D, the four regions formed by the line segment C, the line segment D, and the surface layer region E are W, X, Y, and Z, respectively.
Based on this image, the number of domains B of the release agent existing in each region W, X, Y, Z is measured in the same manner as the above-described measurement of the number of domains B. Furthermore, the surface layer domain variation coefficient of the domain B of the release agent is calculated by the following formula.
Surface domain variation coefficient=“standard deviation of the number of domains B existing in the areas W, X, Y, Z”/“average value of the number of domains B existing in the areas W, X, Y, Z”×100 (% )

<Measurement of Ratio of Toner Having Domain A of Release Agent at Central Point of Toner Cross Section (Center Ratio)>
Based on the image obtained by the above STEM observation, the center point of the toner cross section is obtained by the following work. Using image processing software, clarify the toner outline (edge detection) from the toner cross section. Next, the point guided by the center of gravity from the cross section of the toner is set as the center point of the toner. After that, the number of toner cross-sections when the release agent domain A is present at the center point and the number of toner cross-sections when the release agent domain A is not present are measured for 100 or more toner cross-sections. Then, the center ratio is calculated using the following formula.
Center ratio=“number of toner cross sections in which the domain A of the release agent is present at the center point”/“measured number of toner cross sections”×100 (number%)

<Measurement of glass transition temperature Tg (°C) of toner particles and binder resin>
The glass transition temperature Tg (° C.) of the toner particles and the binder resin is measured according to ASTM D3418-82 using a differential scanning calorimeter “Q1000” (manufactured by TA Instruments). The melting point of indium and zinc is used to correct the temperature of the device detection unit, and the heat of fusion of indium is used to correct the amount of heat.
Specifically, about 10 mg of a measurement sample such as toner particles is precisely weighed and placed in an aluminum pan, and an empty aluminum pan is used as a reference, and the temperature is raised within a measurement range of 30 to 200°C. The measurement is performed at a speed of 10° C./min. During this temperature raising process, the temperature is 40°C to 10°C.
A specific heat change can be obtained in the range of 0°C. The glass transition temperature Tg of the sample is defined as the intersection of the line at the midpoint of the baseline before and after the change in the specific heat and the differential heat curve.

<Measurement of crystallization point>
The crystallization point of the release agent is measured using a differential scanning calorimeter "Q1000" (manufactured by TA Instruments).
The melting point of indium and zinc is used to correct the temperature of the device detection unit, and the heat of fusion of indium is used to correct the amount of heat.
Specifically, 1 mg of the mold release agent is precisely weighed and placed in an aluminum pan, and an empty aluminum pan is used as a reference. Modulation measurements are performed at the following settings between 20°C.
・Raising rate 1℃/min
・Amplitude temperature range ±0.318℃/min
・Cooling rate 1℃/min
・Amplitude temperature range ±0.318℃/min
In this temperature decreasing process, a specific heat change is obtained in the temperature range of 140°C to 20°C. The crystallization point of the release agent is the maximum exothermic peak temperature in the specific heat change curve.

Hereinafter, the present invention will be specifically described with reference to production examples and examples, but the present invention is not limited thereto. In the following formulation, all parts are based on mass unless otherwise specified. In addition, Example 17 (toner 17) is a reference example.

<Production example of magnetic iron oxide>
Fifty liters of a ferrous sulfate first aqueous solution containing 2.0 mol/L of Fe ²⁺ was mixed with 55 liters of a 4.0 mol/L sodium hydroxide aqueous solution and stirred to give a ferrous salt aqueous solution containing a ferrous hydroxide colloid. Obtained. This aqueous solution was maintained at 85° C., and an oxidation reaction was performed while blowing air at 20 L/min to obtain a slurry containing core particles.
After filtering and washing the obtained slurry with a filter press, the core particles were dispersed again in water and reslurried. To this reslurry liquid, sodium silicate that becomes 0.20 mass% in terms of silicon per 100 parts of core particles is added, the pH of the slurry liquid is adjusted to 6.0, and the magnetic oxidation having a silicon-rich surface is performed by stirring. Iron particles were obtained. The obtained slurry was filtered with a filter press, washed, and reslurried with ion-exchanged water. To this reslurry liquid (solid content 50 g/L), 500 g (10% by mass with respect to magnetic iron oxide) of ion exchange resin SK110 (manufactured by Mitsubishi Kagaku Co., Ltd.) was charged and stirred for 2 hours to perform ion exchange. Then, the ion exchange resin was removed by filtration through a mesh, filtered and washed with a filter press, dried and crushed to obtain magnetic iron oxide having a number average diameter of 0.23 μm.

<Production of silane compound>
30 parts of iso-butyltrimethoxysilane was added dropwise to 70 parts of ion-exchanged water while stirring. Thereafter, this aqueous solution was maintained at pH 5.5 and a temperature of 55° C., and dispersed by using a Disper blade at a peripheral speed of 0.46 m/s for 120 minutes to perform hydrolysis. Then, the pH of the aqueous solution was adjusted to 7.0 and cooled to 10° C. to stop the hydrolysis reaction. Thus, an aqueous solution containing the silane compound was obtained.

<Production of colorant>
100 parts of the magnetic iron oxide was placed in a high-speed mixer (LFS-2 type manufactured by Fukae Powtec Co., Ltd.), and 8.0 parts of an aqueous solution containing a silane compound was added dropwise over 2 minutes while stirring at a rotation speed of 2000 rpm. Then, the mixture was mixed and stirred for 5 minutes. Then, in order to improve the adhesion of the silane compound, the mixture was dried at 40° C. for 1 hour to reduce the water content, and then the mixture was dried at 110° C. for 3 hours to promote the condensation reaction of the silane compound. Then, it was disintegrated and passed through a sieve having an opening of 100 μm to obtain Colorant 1.

<Release agents 1-5>
Table 1 shows the properties of the release agent used in Examples and Comparative Examples.

<Production Method of Toner 1>
After warming to 60 ° C. was charged with 0.1 mol / _L-Na 3 PO ₄ aqueous solution 450 parts to 720 parts of deionized water, with the addition of 1.0 mol / L-CaCl ₂ aqueous solution 67.7 parts An aqueous medium containing a dispersion stabilizer was obtained.
-Styrene 78.0 parts-n-butyl acrylate 22.0 parts-Divinylbenzene 0.55 parts-Monoazo dye iron complex (T-77: Hodogaya Chemical Co., Ltd.) 1.0 part-Colorant 90.0 parts The formulation was uniformly dispersed and mixed using an attritor (Nippon Coke Industry Co., Ltd.) to obtain a monomer composition. This monomer composition was heated to 63° C., 10 parts by mass of the mold release agent 1 was added and mixed therein, and dissolved for 45 minutes. Thereafter, 5.0 parts by mass of a polymerization initiator tert-butyl peroxypivalate was dissolved.
The above-mentioned monomer composition was put into the above-mentioned aqueous medium, and stirred at 60°C under N2 atmosphere with a TK homomixer (Primix Kogyo Co., Ltd.) at 12000 rpm for 10 minutes to granulate. Then, the mixture was reacted at 70° C. for 4 hours while stirring with a paddle stirring blade.
Then, the aqueous medium as a suspension was heated to 95° C. and held for 30 minutes. Then, 5° C. water was added to the aqueous medium, and the mixture was cooled from 95° C. to 50° C. at a cooling rate of 135° C./min. (In this case, the starting temperature T1 is 95° C., the stopping temperature T2 is 50° C., and the cooling rate is 135° C./min.)
Subsequently, the aqueous medium that had undergone the previous step was held at 50° C. for 60 minutes. (In this case, the starting temperature T3 is 50° C., and the holding time in the temperature region of Tg±10° C. of the toner particles is 60 minutes.)
Then, hydrochloric acid was added to the aqueous medium to wash and remove the calcium phosphate, and the mixture was filtered and dried to obtain toner particles 1 having a weight average particle diameter (D4) of 8.0 μm. The glass transition point (Tg) of the toner particles 1 was 57°C.
Then, 100 parts by mass of the toner particles 1 and 0.8 parts by mass of hydrophobic silica fine particles having a BET value of 300 m ² /g and a primary particle diameter of 8 nm were mixed with a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Toner 1 was obtained by mixing. The content of the styrene-acrylic resin in the binder resin of the obtained toner 1 was 100% by mass. Table 3 shows the physical properties of Toner 1.

<Production of Toners 2 to 18 and Comparative Toners 1 to 11>
In the production of Toner 1, toners 2 to 18 and comparative toner are similarly used except that the binder resin, the release agent, the dissolution time after the release agent is added, and the conditions of the cooling step are changed as shown in Table 2. 1 to 11 were manufactured. Table 2 shows the composition and production conditions of the obtained toner and comparative toner. The Tg of the toner particles of Toners 8 to 11 and 18 was 57°C. Further, the polyester used in Toners 8 to 11 and 18 is a saturated polyester obtained by the condensation reaction of an ethylene oxide 2 mol adduct of bisphenol A and terephthalic acid, and has a resin weight average molecular weight (Mw) of 20,000 and a Tg of 57. ℃.

表中、保持時間は、冷却工程後のＴｇ±１０℃の温度領域での保持時間を示す。なお、保持時間が０のものは、該保持を行わなかったことを意味する。

In the table, the holding time indicates the holding time in the temperature range of Tg±10° C. after the cooling step. A holding time of 0 means that the holding was not performed.

<Production of Comparative Toner 12>
(Synthesis of low molecular weight polyester 1)
The following raw materials were charged into a heat-dried two-necked flask while introducing nitrogen.
Bisphenol A ethylene oxide 2 mol adduct: 229 parts Bisphenol A propylene oxide 3 mol adduct: 529 parts Terephthalic acid: 208 parts Adipic acid: 46 parts Dibutyltin oxide: 2 parts The mixture was stirred for 5 hours. Then, the temperature was gradually raised to 230° C. under reduced pressure while continuing the stirring, and the temperature was further held for 3 hours. , [Low molecular weight polyester 1] were obtained.

(Production of Release Agent Dispersion Liquid 1)
Release agent 2 (melting point 82° C.): 5 parts Low molecular weight polyester 1:25 parts Ethyl acetate: 67.5 parts Ion-exchanged water: 200.0 parts Mix the above and add 3 mm zirconia at 60% volume ratio. Paint conditioner NO. 5400 type (manufactured by RED DEVIL, USA) was dispersed until the weight average particle diameter (D4) was 400 nm to obtain a release agent dispersion liquid 1.

(Production of Release Agent Dispersion Liquid 2)
In the production of the release agent dispersion liquid 1, except that the release agent 2 (5 parts) is changed to the release agent 3 (2.5 parts) and the weight average particle diameter (D4) is 1.5 μm. In the same manner, a release agent dispersion liquid 2 was manufactured.

(Synthesis of Amorphous Resin 1)
The following raw materials were charged into a heat-dried two-necked flask while introducing nitrogen.
Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane
30 parts polyoxyethylene (2.2)-2,2-bis(4-hydroxyphenyl)propane
34 parts terephthalic acid 30 parts fumaric acid 6.0 parts dibutyltin oxide 0.1 part The system was replaced with nitrogen by depressurizing operation, and then stirred at 215° C. for 5 hours. After that, the temperature is gradually raised to 230° C. under reduced pressure while continuing stirring, and the temperature is further maintained for 2 hours. When it became a viscous state, it was air-cooled and the reaction was stopped to obtain an amorphous resin 1 which was an amorphous polyester.

(Production of Resin Particle Dispersion Liquid 1)
50.0 parts of the amorphous resin 1 is dissolved in 200.0 parts of ethyl acetate, and 3.0 parts of an anionic surfactant (sodium dodecylbenzenesulfonate) is added together with 200.0 parts by mass of ion-exchanged water. Heat to 40°C and emulsify machine (IKA, Ultra Turrax T-50
) Was stirred for 10 minutes at 8000 rpm, and then ethyl acetate was volatilized and removed to obtain a resin particle dispersion liquid 1.

(Preparation of Colorant Dispersion Liquid 1)
Colorant 1: 50.0 parts Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku Co., Ltd.): 5.0 parts Ion-exchanged water: 200.0 parts by mass Add the above materials to a heat resistant glass container, Paint conditioner NO. 5400 type (manufactured by REDDEVIL, USA) is dispersed for 5 hours, glass beads are removed with a nylon mesh to obtain a colorant dispersion liquid 1 having a volume-based median diameter (D50) of 220 nm and a solid content of 20% by mass. It was

(Production process of comparative toner 12)
Colorant dispersion 1: 25.0 parts Release agent dispersion 1: 30.0 parts Release agent dispersion 2: 30.0 parts 10 mass% polyaluminum chloride aqueous solution 1.5 parts The above is a round stainless steel flask. After mixing in and mixing and dispersing with Ultra Turrax T50 manufactured by IKA, the mixture was kept at 45° C. for 60 minutes while stirring (aggregation step). Then, the resin particle dispersion liquid 1 (50 parts by mass) was slowly added, the pH in the system was adjusted to 6 with a 0.5 mol/L sodium hydroxide aqueous solution, the stainless steel flask was closed, and a magnetic seal was used. And heated to 96° C. with continuous stirring. Until the temperature was raised, a sodium hydroxide aqueous solution was appropriately added to prevent the pH from becoming lower than 5.5. Then, it hold|maintained at 96 degreeC for 5 hours (fusion process).
Then, after cooling, filtration and sufficient washing with ion-exchanged water, solid-liquid separation was performed by Nutsche suction filtration. This was further redispersed in 3 L of ion exchanged water, and stirred and washed at 300 rpm for 15 minutes. This was further repeated 5 times, and when the pH of the filtrate reached 7.0, solid-liquid separation was performed by Nutsche suction filtration using filter paper. Then, vacuum drying was continued for 12 hours to obtain comparative toner particles 12.
Then, 100 parts by mass of the comparative toner particles 12 and 0.8 parts by mass of hydrophobic silica fine particles having a BET value of 300 m ² /g and a primary particle size of 8 nm were mixed with a Henschel mixer (Mitsui Miike Kako Co., Ltd.). Comparative toner 12 was obtained.

<Production of Comparative Toner 13>
(Preparation of release agent solution 1)
-Release agent 4 51.0 parts by mass-Styrene 104.0 parts by mass-n-butyl acrylate 53.0 parts by mass-Methacrylic acid 8.0 parts by mass-n-octyl mercaptan 4.0 parts by mass The solution was placed in a flask, heated to 85° C. and stirred to obtain a release agent solution 1.

(Preparation of resin emulsion 1)
-Styrene 63.0 parts by mass-n-butyl acrylate 32.0 parts by mass-Methacrylic acid 5.0 parts by mass-n-octyl mercaptan 2.0 parts by mass The above components are used as anionic surfactant (sodium dodecylbenzenesulfonate). ) 2.02 parts of ion-exchanged water dissolved therein was slowly added dropwise, heated to 78° C. and stirred for 1 hour to obtain a resin emulsion 1.

(Preparation of resin particle dispersion 2)
2.0 parts of an anionic surfactant (sodium dodecylbenzenesulfonate) was dissolved in 1100 parts of ion-exchanged water and heated to 90° C., and 28 parts of resin emulsion 1 was added. Subsequently, using Ultra Turrax T50 manufactured by IKA, the release agent solution 1 was added and dispersed for 4 hours, and an initiator aqueous solution obtained by dissolving 2.5 parts of a polymerization initiator (KPS) in 110 parts of ion-exchanged water was added. .. This system was stirred at 90° C. for 2 hours to obtain a resin particle dispersion liquid 2.

(Preparation of Resin Particle Dispersion Liquid 3)
・Styrene 2.0 parts by mass ・Methyl methacrylate 77.0 parts by mass ・n-Butyl acrylate 16.0 parts by mass ・Itaconic acid 5.0 parts by mass ・n-octyl mercaptan 2.0 parts by mass It was added dropwise to 2800 parts of ion-exchanged water in which 2.7 parts of the activator (sodium dodecylbenzenesulfonate) was dissolved. Then, it was dispersed by Ultra Turrax T50 manufactured by IKA Co., and an initiator aqueous solution obtained by dissolving 11 parts of a polymerization initiator (KPS) in 400 parts of ion-exchanged water was added. This system was stirred at 78° C. for 2 hours to obtain a resin particle dispersion liquid 3.

(Preparation of Colorant Dispersion Liquid 1)
Colorant 1 50.0 parts by mass Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku Co., Ltd.) 5.0 parts by mass Deionized water 200.0 parts by mass Add the above materials to a heat resistant glass container and paint. Conditioner NO. 5400 type (manufactured by REDDEVIL, USA) is dispersed for 5 hours, glass beads are removed with a nylon mesh to obtain a colorant dispersion liquid 1 having a volume-based median diameter (D50) of 220 nm and a solid content of 20% by mass. It was

(Production process of comparative toner 13)
Colorant dispersion 1 200.0 parts by mass Resin particle dispersion 2 360.0 parts by mass Resin particle dispersion 3 40.0 parts by mass Deionized water 1100.0 parts by mass 50% by mass magnesium chloride aqueous solution 120 parts by mass Type stainless steel flask, mixed and dispersed with IKA ULTRA TURRAX T50, and then held at 30° C. for 60 minutes while stirring (aggregation step). After that, the pH of the system was adjusted to 10 with a 0.5 mol/L sodium hydroxide aqueous solution, the stainless steel flask was closed, and the mixture was heated to 80° C. while maintaining stirring with a magnetic seal and held (fusion). Process).
Then, after cooling, filtration and sufficient washing with ion-exchanged water, solid-liquid separation was performed by Nutsche suction filtration. This is further redispersed in 3 L of ion exchanged water, and stirred and washed at 300 rpm for 15 minutes. This was further repeated 5 times, and when the pH of the filtrate reached 7.0, solid-liquid separation was performed by Nutsche suction filtration using filter paper. Then, vacuum drying was continued for 12 hours to obtain comparative toner particles 13.
Then, 100 parts by mass of the comparative toner particles 13 and 0.8 parts by mass of hydrophobic silica fine particles having a BET value of 300 m ² /g and a primary particle size of 8 nm were mixed with a Henschel mixer (Mitsui Miike Kako Co., Ltd.). Comparative toner 13 was obtained.
Table 3 shows the physical properties of the obtained toner.

比較用トナー１、２では、ドメインＡに該当するドメインが存在しなかった。また、比較用トナー３，４，８，９では、ドメインＢに該当するドメインが存在しなかった。

In comparative toners 1 and 2, no domain corresponding to domain A was present. Further, in the comparative toners 3, 4, 8 and 9, there was no domain corresponding to the domain B.

<Example 1>
<Evaluation 1. Low temperature fixability (peeling)>
The following evaluations were performed using Toner 1 for Examples.
As the image forming apparatus, LBP-6300 (manufactured by Canon Inc.) was used, and the process speed was modified to 300 mm/sec, which is about 1.5 times. Since the printing speed is increased, it is possible to perform a severe evaluation that the fixing property of the toner is deteriorated. Further, the temperature control of the fixing device was lowered by 10°C to 190°C. In the environment of 23° C. and 50% RH, the fixing device was removed between evaluations, and the fixing device was cooled sufficiently by using a fan or the like, and the following evaluation was performed. By sufficiently cooling the fixing device after the evaluation, the temperature of the fixing nip portion that has risen after the image is output is cooled, so that the fixing property of the toner can be evaluated severely and more reproducibly.
For the evaluation of peeling, FOX RIVER BOND paper (110 g/m ² , the above 23° C., 50% RH environment, left for 48 hours or more) was used. By using a thick paper having a relatively large surface irregularity and using a paper that has been left to stand, it is possible to perform a strict evaluation on the peeling of the printed image.
Using toner 1, a solid black image was output on the above-mentioned abandoned paper while the fixing device was sufficiently cooled. At this time, the amount of toner deposited on the paper was adjusted to be 9 g/m ² .
In the evaluation result of Toner 1, a good solid black image without white spots and peeling was obtained. The criteria for peeling are described below.
A: Very good (no peeling)
B: Good (slightly peeled off when seen closely)
C: Normal (peeling is visible but not noticeable)
D: Bad (peeling is noticeable)

<Evaluation 2. Readability (crushed fine lines)>
The modified machine used in Evaluation 1 was used as the image forming apparatus, and evaluation was performed in an environment of 23° C. and 50% RH. Since the printing speed is increased, it is possible to perform a strict evaluation that the developability of the toner also decreases. As the fixing medium, B5 color laser copy paper (manufactured by Canon, 40 g/m ² ) was used. By making the area of the medium small, the fixing device can easily retain heat excessively, and by using thin paper, the amount of heat taken by the paper from the fixing device becomes small. By carrying out such an examination, the toner is likely to be excessively exposed to heat, and a strict evaluation can be made on the collapse of the fine line. A character image of 3 points and 5 points was formed, and rank evaluation was performed as follows. In the evaluation result of Toner 1, a good image without crushing could be obtained.
A: Very good (3 points and 5 points are clear and easily readable)
B: Good (3 points are legible even though some of them are crushed, 5 points are clear and easily legible)
C: Normal (3 points are partially illegible characters, 5 points are partially crushed but legible)
D: Bad (most characters are unreadable at 3 points, and some or all of 5 points are unreadable)

<Evaluation 3. Image density after leaving in harsh environment>
The modified machine used in Evaluation 1 was used as the image forming apparatus, and evaluation was performed in an environment of 23° C. and 50% RH. Since the printing speed is increased, it is possible to perform a strict evaluation that the developability of the toner also decreases. The cartridge used was a modified cartridge in which the sleeve having a diameter of 14 mm was changed to the sleeve having a diameter of 10 mm as the developing sleeve. When a cartridge equipped with a developing sleeve having a small diameter is used, the chances of developing the toner from the developing sleeve to the photoconductor are reduced, so that the developability, especially the image density can be strictly evaluated. A4 color laser copy paper (manufactured by Canon, 80 g/m ² ) was used as the fixing medium.
Using this modified cartridge, toner 1 after being left in a harsh environment shown below was used, and ten solid images were continuously output. The obtained 10 solid images were measured using a printed image density (Macbeth reflection densitometer (manufactured by Macbeth Co.), and the average value was taken as the solid density. The higher the solid density, the better after standing in a harsh environment. Indicates that there is.
In the above evaluation result of Toner 1, a high image density and a good image could be obtained.
The criteria for determining the image density are described below.
A: Very good (1.40 or more)
B: Good (1.30 or more and less than 1.40)
C: Normal (1.20 or more and less than 1.30)
D: Bad (less than 1.20)

(Left in a harsh environment)
100 g of toner is placed in a constant temperature bath adjusted to a temperature of 21° C. and a humidity of 90%, and an aging treatment is performed for 24 hours.
Then, the temperature is raised at a rate of 12° C. per hour, and the temperature is adjusted to 57° C. 90% over 3 hours.
In that state, after holding for 3 hours, the temperature is lowered at a rate of 12° C. per hour, and the temperature is returned to 21° C. 90%. After holding for 3 hours, the temperature is raised again. In this way, as shown in FIG. 1, heating and cooling were repeated 10 times at the temperature and humidity of 21° C. 90% and 57° C. 90%.
In this mode, rapid heat fluctuation is applied to the toner, high temperature and low temperature are repeated many times to promote mass transfer inside the toner, and the release agent easily exudes to the toner surface. Is a mode that is relatively strict with respect to toner. If left in this environment and the release agent oozes out on the toner surface, the external additive may be embedded in the toner base, and the image density decreases.

<Examples 2 to 18>
An image output test was conducted in the same manner as in Example 1 except that the toner 1 was changed to the toners 2 to 18. As a result, all toners were peeled, crushed, and had no problem in the image density after being left in a harsh environment, and were C rank or higher. The evaluation results are shown in Table 4.

<Comparative Examples 1 to 13>
An image formation test was performed in the same manner as in Example 1 except that the toner 1 was changed to the comparative toners 1 to 13. As a result, the performance was lower than that of Examples 1 to 18 in any of the peeling, crushing, and image density after being left in a severe environment. The evaluation results are shown in Table 5.

100: electrostatic latent image carrier (photoconductor), 102: toner carrier, 103: developing blade, 114: transfer member (transfer charging roller), 116: cleaner, 117: charging member (charging roller), 121: laser Generator (latent image forming means, exposure device), 123: laser, 124: pickup roller, 125: conveyor belt, 126: fixing device, 140: developing device, 141: stirring member

Claims (4)

A method for producing a toner, the method comprising producing a toner having toner particles containing a binder resin, a release agent and a colorant,
The manufacturing method is
A step of producing the toner particles,
The crystallization temperature of the release agent is Tc (°C), and the glass transition temperature of the toner particles is Tg (°C).
), the aqueous medium in which the toner particles are dispersed is referred to as Tc (°C) and Tg (°C).
A process of cooling from a higher temperature to a temperature below the Tg (°C) at a cooling rate of 5.00°C/min or more.
(I) and
The water-based medium that has undergone the step (i) is treated in the temperature range of ±10°C of the Tg (°C) in 3
A step of holding for 0 minutes or more (ii),
In that order,
In the toner of the cross section was observed by scanning transmission electron microscopy,
The release agent forms a domain,
The major axis of the cross section of the toner is R (μm), the major axis of the domain of the release agent present in the cross section of the toner is r (μm), and r/R of the domains of the release agent is 0. When the domain of 125≦r/R≦0.375 is the domain A and the domain of r/R is 0.000625≦r/R≦0.0625 is the domain B, the phase of the major axis R of the cross section of the toner is determined. The average value satisfies 4≦R≦12,
In the cross section of the toner, when the ratio of the area occupied by the domain A is SA and the ratio of the area occupied by the domain B is SB, the SA and the SB satisfy the following formulas (1) and (2). ,
2.5%≦SA≦30% (1)
0.1≦SB/SA≦0.8 (2)
A method for producing a toner , wherein an aspect ratio of the domain B in the toner cross section is 0.3 or less. The method for producing a toner according to claim 1, wherein a proportion of the toner in which the domain A of the release agent is present at the center point of the cross section of the toner is 80 number% or more. The method for producing a toner according to claim 1, wherein the content of the styrene-acrylic resin is 80% by mass or more based on the total amount of the binder resin. The surface layer area within 1.0 μm from the surface of the toner in the cross section of the toner is E, the chord giving the maximum length of the cross section of the toner is a line segment C, and the line segment passing through the midpoint of the line segment C When a chord orthogonal to C is defined as a line segment D, and four regions formed by the line segment C, the line segment D, and the region E are defined as W, X, Y, and Z, respectively,
Region W, X, Y, variation coefficient of the number of the domain B present in Z The method for producing a toner according to any one of claims 1 to 3, 40% or less.

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