JP2011186251A - Method for manufacturing toner, and toner - Google Patents

Abstract

To provide a toner manufacturing method capable of efficiently manufacturing a toner having a small variation in charging characteristics between toner particles and excellent cleaning characteristics.
A method for producing a toner of the present invention includes a resin solution preparation step of preparing a resin solution containing a resin material, a colorant, and kaolinite, wherein at least a part of the resin material is dissolved in an organic solvent. In addition, an O / W emulsion preparation step for preparing an O / W emulsion via a W / O emulsion by adding an aqueous liquid to the resin solution, and included in the O / W emulsion And the dispersoid to be coalesced to obtain coalesced particles, and the organic solvent removing step of removing the organic solvent contained in the coalesced particles.
[Selection figure] None

Description

  The present invention relates to a toner manufacturing method and a toner.

In general, image forming apparatuses such as printers, copiers, and facsimile machines adopting an electrophotographic system generally transfer toner images to paper through a series of image forming processes including a charging process, an exposure process, a developing process, a transfer process, and a fixing process. Formed on a recording medium.
Such an image forming apparatus is provided with a developing device having a developing roller for carrying toner. Such a developing device is used in a state in which a developing roller is opposed to a photosensitive drum carrying an electrostatic latent image. By applying toner from the developing roller to the photosensitive drum, the latent image on the photosensitive drum is converted into a toner image. Visualize (develop).
As a method for producing the toner, a pulverization method, a polymerization method, or the like is used (for example, see Patent Document 1).

  The toner particles are generally formed in a substantially spherical shape for the purpose of reducing variation in charging characteristics among the particles, but if the circularity is too large, the toner remaining on the photosensitive member is cleaned. When the toner particles are removed by the blade, the toner particles rotate between the photosensitive member and the cleaning blade and enter the gap, and there is a problem that cleaning is difficult. In order to obtain toner particles having an appropriate degree of circularity, there is a method in which a mechanical force is applied after granulation to reduce the circularity of the toner particles. There is a problem that unintentional agglomeration, cracking of particles and the like are likely to occur.

JP 2009-058844 A

  An object of the present invention is to provide a toner production method capable of efficiently producing a toner having a small variation in charging characteristics among toner particles and having excellent cleaning characteristics, and charging characteristics between toner particles. It is an object of the present invention to provide a toner having a small variation in toner and excellent cleaning characteristics.

Such an object is achieved by the present invention described below.
The toner manufacturing method of the present invention includes a resin solution preparation step of preparing a resin solution containing a resin material, a colorant, and kaolinite, and at least a part of the resin material is dissolved in an organic solvent;
An O / W emulsion preparation step of preparing an O / W emulsion via a W / O emulsion by adding an aqueous liquid to the resin solution;
A coalescence step of coalescing dispersoids contained in the O / W emulsion to obtain coalesced particles;
An organic solvent removing step of removing the organic solvent contained in the coalesced particles.
Accordingly, it is possible to provide a toner manufacturing method capable of efficiently manufacturing a toner having a small variation in charging characteristics between toner particles and excellent cleaning characteristics.

In the method for producing a toner of the present invention, the kaolinite preferably has an average particle size of 80 nm to 500 nm.
As a result, kaolinite can be effectively unevenly distributed in the vicinity of the surface of the obtained toner particles, and the entire toner particles can be reliably prevented from becoming harder than necessary, and the fixing property of the toner to the recording medium is reduced. The effect of including kaolinite can be more effectively exhibited while reliably preventing this.

In the method for producing a toner of the present invention, it is preferable that the content of the kaolinite in all the components of the toner contained in the resin solution is 0.2 wt% or more and 5.0 wt% or less.
As a result, kaolinite can be effectively unevenly distributed in the vicinity of the surface of the obtained toner particles, and the entire toner particles can be reliably prevented from becoming harder than necessary, and the fixing property of the toner to the recording medium is reduced. The effect of including kaolinite can be more effectively exhibited while reliably preventing this.

In the method for producing a toner of the present invention, the kaolinite is preferably subjected to a surface treatment with a quaternary amine.
As a result, the affinity of kaolinite to the aqueous liquid and the affinity to the resin material can be made suitable, and kaolinite can be more effectively unevenly distributed near the surface of the obtained toner particles. In addition, it is possible to more effectively exert the effect of containing the kaolinite from the toner particles during storage of the produced toner, and to effectively prevent unintentional detachment of the kaolinite.

In the toner manufacturing method of the present invention, it is preferable to use a polyester resin as the resin material.
Thereby, the fixing property of the toner to the recording medium, the color development property, the transparency and the like can be made particularly excellent. Furthermore, the affinity between the resin material and kaolinite can be optimized, and kaolinite can be more effectively unevenly distributed in the vicinity of the surface of the obtained toner particles. In addition to being able to exhibit more effectively, it is possible to effectively prevent unintentional detachment of kaolinite from toner particles when the produced toner is stored.

The toner of the present invention is manufactured using the method of the present invention.
As a result, it is possible to provide a toner with small variations in charging characteristics among toner particles and excellent cleaning characteristics.
In the toner of the present invention, the average circularity of the toner particles is preferably 0.910 or more and 0.965 or less.
Thereby, the variation in charging characteristics among toner particles can be made smaller, and the cleaning characteristics can be made particularly excellent.

FIG. 3 is a process diagram illustrating a preferred embodiment of a method for producing a toner of the present invention. 1 is a schematic cross-sectional view illustrating an example of an overall configuration of an image forming apparatus to which a toner of the present invention is applied. FIG. 3 is a perspective view showing a developing device provided in the image forming apparatus shown in FIG. 2. FIG. 4 is a schematic cross-sectional view illustrating a schematic configuration of the developing device illustrated in FIG. 3.

Hereinafter, preferred embodiments of the present invention will be described in detail.
≪Toner production method≫
First, a method for producing the toner of the present invention will be described.
FIG. 1 is a process diagram showing a preferred embodiment of a toner production method of the present invention.
As shown in FIG. 1, the toner manufacturing method of the present embodiment prepares a resin solution containing a resin material, a colorant, and mainly kaolinite, and at least a part of the resin material is dissolved in an organic solvent. Resin solution preparation step (S10) and an O / W emulsion preparation step (S20) for preparing an O / W emulsion via a W / O emulsion by adding an aqueous liquid to the resin solution. And coalescence of the dispersoids contained in the O / W emulsion to obtain coalesced particles (S30), and organic solvent removal step of removing the organic solvent contained in the coalesced particles (S40), a washing step (S50) for washing the obtained toner particles, and a drying step (S60) for drying the wet toner particles to obtain toner (aggregate of toner particles) as powder. And have. As a result, it is possible to efficiently produce a toner having a small variation in charging characteristics between toner particles and excellent cleaning characteristics. Further, the particle size distribution of the toner particles constituting the finally obtained toner can be made very sharp, and the variation in characteristics among the toner particles can be made particularly small.

Hereinafter, each step of the toner manufacturing method will be described in detail.
[Resin solution preparation process]
First, a resin material is dissolved in an organic solvent, and a resin solution containing a colorant and kaolinite is prepared.
<Organic solvent>
The organic solvent may be any as long as it dissolves at least a part of the resin material, but it is preferable to use an organic solvent having a boiling point lower than that of the aqueous liquid described later. Thereby, an organic solvent can be easily removed in the process mentioned later.

The organic solvent is preferably one having low compatibility with an aqueous liquid (aqueous dispersion medium) described later (for example, one having a solubility in 100 g of aqueous liquid at 25 ° C. of 30 g or less). Thereby, in the O / W emulsion (aqueous emulsion) described later, the dispersoid composed of the toner material can be finely dispersed in a stable state.
Moreover, the composition of the organic solvent can be appropriately selected according to, for example, a resin material, a composition of a colorant, a composition of an aqueous liquid (aqueous dispersion medium), and the like as described later.
Such an organic solvent is not particularly limited, and examples thereof include ketone solvents such as MEK and aromatic hydrocarbon solvents such as toluene.

<Resin material>
The resin material constituting the resin solution functions as a binder resin (binder) in the finally obtained toner. By using such a component, the toner can be excellently fixed on the recording medium. The resin material constituting the resin solution may be a material that is modified during the toner production process (for example, a material having a high degree of polymerization).

The resin material is not particularly limited. For example, a known resin can be used, but a polyester resin is preferably used. Thereby, the fixing property of the toner to the recording medium, the color development property, the transparency and the like can be made particularly excellent. Furthermore, the affinity between the resin material and kaolinite, which will be described in detail later, can be optimized, and kaolinite can be more unevenly distributed near the surface of the resulting toner particles, including kaolinite. As a result, it is possible to effectively prevent the kaolinite from being removed from the toner particles when the produced toner is stored.
In the present invention, the resin material may be composed of a single component or may include a plurality of types of resin components.

<Colorant>
As the colorant, various pigments, various dyes and the like can be used.
<Kaolinite>
In the present invention, kaolinite is used. Thereby, the toner particles constituting the finally obtained toner contain kaolinite. As a result, the circularity of the toner particles can be appropriately reduced, and as a result, the variation in charging characteristics among the toner particles can be sufficiently reduced and the cleaning characteristics can be improved. it can.

  In addition, the toner is usually fixed by heating. By using toner particles containing kaolinite, the heat energy applied to the toner can be efficiently transmitted to the resin material, so that the energy required for fixing is reduced. From the viewpoint of energy saving. Further, even when the fixing temperature is relatively low, the toner can be reliably fixed on the recording medium, and can be suitably adapted to high-speed printing.

Further, when the toner particles contain kaolinite, the charging characteristics of the toner particles as a whole can be made particularly excellent. This is considered to be because the kaolinite constituting the toner particles has a specific composition, so that charges can be effectively retained.
Further, kaolinite itself does not adversely affect the color of the formed image.
Kaolinite is dispersed in the resin solution.

Kaolinite has Al ₂ Si ₂ O ₅ (OH) ₄ as an ideal chemical composition. With kaolinite having such a composition, it is possible to improve the affinity of kaolinite for an aqueous liquid as described later and the affinity for a resin material, and in the vicinity of the surface of the finally obtained toner particles. Kaolinite can be more unevenly distributed in the toner, and the effect of including kaolinite can be more effectively exhibited. Intentional omission can be effectively prevented.
As described above, kaolinite has Al ₂ Si ₂ O ₅ (OH) ₄ as an ideal chemical composition, but may contain other components.

  For example, kaolinite is preferably subjected to a surface treatment with a quaternary amine (particularly, tetraalkylammonium). As a result, the affinity of kaolinite for aqueous liquids and resin materials can be made suitable, and kaolinite can be more effectively unevenly distributed in the vicinity of the surface of the finally obtained toner particles. The effect of containing kaolinite can be more effectively exhibited, and the unintentional dropping of kaolinite from the toner particles during storage of the produced toner can be effectively prevented.

  The average particle size of kaolinite is not particularly limited, but is preferably 80 nm or more and 500 nm or less, and more preferably 80 nm or more and 300 nm or less. As a result, kaolinite can be effectively unevenly distributed in the vicinity of the surface of the finally obtained toner particles, and the entire toner particles can be reliably prevented from becoming harder than necessary, and the toner can be fixed on the recording medium. The effect of including kaolinite can be more effectively exhibited while reliably preventing the deterioration of the properties.

Moreover, the shape of kaolinite is not specifically limited, For example, a cylindrical shape may be sufficient. When the kaolinite has a cylindrical shape, the charging characteristics of the toner particles as a whole finally obtained can be made particularly excellent.
Further, when the kaolinite has a cylindrical shape, an appropriate gap can be secured between the toner particles transferred onto the recording medium in the transfer step in the image forming method as described later. When fixing the toner in the toner image, the toner particles can be surely melted on the recording medium, and the melted toner particles can be surely mixed with each other. Can be expressed.

  Further, when the toner containing the wax is produced when the kaolinite has a cylindrical shape, the toner finally obtained is preferably a wax in the hollow portion of the cylindrical kaolinite during storage. It can be held and can prevent the occurrence of harmful effects due to the seepage of wax, and can be released to the outside of the cylindrical kaolinite during fixing, ensuring the function of the wax. It will be something that can be exhibited.

  The content of kaolinite in all the components of the toner contained in the resin solution is not particularly limited, but is preferably 0.2 wt% or more and 5.0 wt% or less, preferably 0.5 wt% or more and 3.0 wt%. % Or less is more preferable. When the content of kaolinite is a value within the above range, kaolinite can be effectively unevenly distributed near the surface of the finally obtained toner particles, and the entire toner particles are hardened more than necessary. The effect of containing kaolinite can be more effectively exhibited while reliably preventing and reliably preventing the toner from fixing to the recording medium.

<Wax>
The resin solution prepared in this step only needs to contain a resin material, a colorant, and kaolinite as a constituent material of the toner, but may further contain a wax. Thereby, the releasability of the finally obtained toner can be made excellent. Further, when the kaolinite has a cylindrical shape, the toner finally obtained by containing the wax in the resin solution can suitably hold the wax in the hollow portion of the kaolinite during storage. It is possible to reliably prevent the occurrence of harmful effects due to the exudation of wax, and at the time of fixing, the wax can be released to the outside of the hollow part of kaolinite to ensure that the function of the wax is exhibited. Will be able to.

  Examples of the wax include hydrocarbon waxes such as ozokerite, cercin, paraffin wax, microwax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, methyl palmitate , Ester stearate such as methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, fatty acid ester, polyglycerin fatty acid ester, polyethylene wax, polypropylene wax, oxidized polyethylene wax, Olefinic wax such as oxidized polypropylene wax, 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide Amide-based wax, laurone, ketone waxes such as stearone, ether waxes and the like, may be used singly or in combination of two or more of these, among others, carnauba wax are preferred. Thereby, the effects as described above are more remarkably exhibited.

<Other ingredients>
Further, the resin solution may contain components other than those described above as the constituent components of the toner to be produced. Examples of such components include magnetic powder and a charge control agent.
Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides, and magnetic materials such as Fe, Co, and Ni. The thing etc. which were comprised with the magnetic material containing a metal are mentioned.

As the charge control agent, for example, a metal salt of benzoic acid, a metal salt of salicylic acid, a metal salt of benzyl acid, a metal salt of alkyl salicylic acid, an azo pigment, a metal-containing bisazo dye, a phenolic condensate of calixarene type, Examples include catechol metal salts, chlorinated polyesters, fluorine-containing compounds, and the like.
The content of the solid content (all the constituent components of the toner) in the resin solution is not particularly limited, but is preferably 40 wt% or more and 75 wt% or less, more preferably 50 wt% or more and 73 wt% or less, and 50 wt%. More preferably, it is 70 wt% or less. When the solid content is a value within the above range, the shape of the finally obtained toner particles can be more surely suitable.

The resin solution can be obtained, for example, by mixing a resin material, a colorant, kaolinite, an organic solvent, etc. with a stirrer or the like. Examples of the stirrer that can be used for preparing the resin solution include DESPA (manufactured by Asada Tekko Co., Ltd.), T.C. K. Robotics / T. K. Examples thereof include a high-speed stirrer such as a homodisper 2.5-type blade (manufactured by Primex).
The material temperature during stirring is preferably 20 ° C. or higher and 60 ° C. or lower, and more preferably 30 ° C. or higher and 50 ° C. or lower.
In preparing the resin solution, all the components of the resin solution to be prepared may be mixed at the same time, or a part of the components of the resin solution to be prepared is mixed in advance to prepare a mixture (master). After that, the mixture (master) may be mixed with other components.

[O / W emulsion preparation process]
Next, an O / W emulsion is prepared via the W / O emulsion by adding an aqueous liquid to the resin solution.
As the aqueous liquid, a liquid mainly composed of water can be used.
The aqueous liquid may contain, for example, a solvent having excellent compatibility with water (for example, a solvent having a solubility in 100 parts by weight of water at 25 ° C. of 50 parts by weight or more).
In addition, an emulsifying dispersant may be added to the aqueous liquid as necessary. By adding an emulsifying dispersant, an aqueous emulsion can be prepared more easily. The emulsifying dispersant is not particularly limited, and for example, a known emulsifying dispersant can be used.

  In preparing the O / W emulsion, for example, a basic substance may be used. Thereby, for example, the functional group (for example, carboxyl group) possessed by the resin material can be neutralized, and the shape and size uniformity of the dispersoid in the prepared O / W emulsion can be improved. Dispersibility can be made particularly excellent. For this reason, the obtained toner particles have a particularly sharp particle size distribution. For example, the basic substance may be added to the resin solution, or may be added to the aqueous liquid. Further, the basic substance may be added in a plurality of times in the preparation of the O / W emulsion.

As a basic substance, sodium hydroxide, potassium hydroxide, ammonia etc. are mentioned, for example, 1 type selected from these, or 2 or more types can be used in combination.
The amount of the basic substance used is preferably an amount equivalent to 1 to 3 times the amount necessary for neutralizing all carboxyl groups of the resin material (1 to 3 equivalents), preferably 1 time. An amount corresponding to 2 times or less (1 equivalent or more and 2 equivalents or less) is more preferable. As a result, an O / W emulsion in which a dispersoid having a suitable shape is dispersed can be obtained, and the particle size distribution of particles obtained in the coalescing step described in detail later can be made sharper. .

  The aqueous liquid may be added to the resin solution by any method, but it is preferable to add the aqueous liquid containing water to the resin solution while stirring the resin solution. That is, it is carried out by gradually adding (dropping) an aqueous liquid into the resin solution while applying shear to the resin solution with a stirrer or the like, and from the W / O type emulsion (W / O emulsion) to the O / W type. It is preferable to perform phase inversion to an emulsion (O / W emulsion). As a result, the uniformity of the size and shape of the dispersoid contained in the O / W emulsion can be made particularly high, and the particle size distribution of the toner particles contained in the finally obtained toner is very sharp. The variation in characteristics among toner particles can be made particularly small.

Examples of the stirrer that can be used for the preparation of the O / W emulsion include DESPA (manufactured by Asada Tekko), T.W. K. Robotics / T. K. Examples thereof include a high-speed stirrer such as a homodisper 2.5-type blade (manufactured by Primics), a slasher (manufactured by Mitsui Mining Co., Ltd.), a Cavitron (manufactured by Eurotech), or a high-speed disperser.
Further, at the time of adding the aqueous liquid to the resin solution, it is preferable to perform stirring so that the blade tip speed is 10 m / second or more and 20 m / second or less, and stirring is performed so as to be 12 m / second or more and 18 m / second or less. It is more preferable. When the blade tip speed is a value within the above range, an O / W emulsion can be obtained efficiently, and the dispersion of the shape and size of the dispersoid in the O / W emulsion should be particularly small. It is possible to make the uniform dispersibility of the dispersoid particularly excellent while preventing the generation of excessively fine dispersoid and coarse particles.

The solid content in the O / W emulsion is not particularly limited, but is preferably 5 wt% or more and 55 wt% or less, and more preferably 10 wt% or more and 50 wt% or less. Thereby, it is possible to make the toner productivity particularly excellent while more surely preventing unintentional aggregation of dispersoids in the O / W emulsion.
In addition, the material temperature in this treatment is preferably 20 ° C. or more and 60 ° C. or less, and more preferably 20 ° C. or more and 50 ° C. or less.

[Joint process]
Next, a plurality of dispersoids are coalesced to obtain coalesced particles. The coalescence of dispersoids usually proceeds as a result of collision of dispersoids containing an organic solvent so that they are integrated.
The coalescence of a plurality of dispersoids is performed by adding an electrolyte to the O / W emulsion while stirring the O / W emulsion. Thereby, coalesced particles can be obtained easily and reliably. Moreover, the particle diameter and particle size distribution of the coalesced particles can be controlled easily and reliably by adjusting the amount of electrolyte added.

It does not specifically limit as electrolyte, Well-known organic and inorganic water-soluble salt etc. can be used 1 type or in combination of 2 or more types.
The electrolyte is preferably a monovalent cation salt. Thereby, the particle size distribution of the obtained coalesced particles can be made particularly sharp. In addition, by using a monovalent cation salt, it is possible to reliably prevent generation of coarse particles in this step.

Moreover, among the above-mentioned, it is preferable that electrolyte is a sulfate (for example, sodium sulfate, ammonium sulfate) or carbonate, and it is especially preferable that it is a sulfate. Thereby, the particle diameter of the coalesced particles can be controlled particularly easily.
The amount of the electrolyte added in this step is preferably 0.5 parts by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the solid content in the O / W emulsion to which the electrolyte is added. More preferably, it is at least 2 parts by weight. As a result, the particle diameter of the coalesced particles can be controlled particularly easily and reliably, and the generation of coarse particles can be reliably prevented.

The electrolyte is preferably added in the form of an aqueous solution. Thereby, while being able to diffuse an electrolyte to the whole O / W emulsion liquid quickly, the addition amount of an electrolyte can be controlled easily and reliably. As a result, coalesced particles having a desired particle size and a very sharp particle size distribution can be obtained.
When the electrolyte is added in the form of an aqueous solution, the concentration of the electrolyte in the aqueous solution is preferably 2 wt% or more and 10 wt% or less, and more preferably 2.5 wt% or more and 6 wt% or less. As a result, the electrolyte can be diffused through the entire O / W emulsion particularly quickly, and the amount of electrolyte added can be easily and reliably controlled. In addition, by adding such an aqueous solution, the content of water in the O / W emulsion when the addition of the electrolyte is completed becomes suitable. For this reason, the growth rate of the coalesced particles after the addition of the electrolyte can be made moderately slow to the extent that productivity does not decrease. As a result, the particle size can be controlled more reliably. In addition, unintentional coalescence of coalesced particles can be reliably prevented.

  When the electrolyte is added as an aqueous solution, the rate of addition of the aqueous electrolyte solution is 0.5 parts by weight or more and 10 parts by weight per 100 parts by weight of the solid content in the O / W emulsion to which the aqueous electrolyte solution is added. It is preferably at least part by weight / minute, more preferably at least 1.5 parts by weight / minute and no more than 5 parts by weight / minute. As a result, it is possible to prevent the uneven concentration of the electrolyte from occurring in the O / W emulsion, and to reliably prevent the generation of coarse particles. Further, the particle size distribution of the coalesced particles becomes sharper. Furthermore, by adding the electrolyte at such a rate, the coalescing rate can be controlled particularly easily, the average particle size of the coalesced particles can be controlled particularly easily, and the toner productivity is particularly excellent. Can be.

The addition of the electrolyte may be performed in a plurality of times. Thereby, the coalesced particle | grains of a desired magnitude | size can be obtained easily and reliably.
Moreover, this process is performed in the state which stirred the O / W emulsion. Thereby, coalesced particles with particularly small variations in shape and size among the particles can be obtained.
For stirring the O / W emulsion, for example, stirring blades such as anchor blades, turbine blades, fiddler blades, full zone blades, max blend blades, and meniscus blades can be used. preferable. As a result, the added electrolyte can be quickly and uniformly dispersed and dissolved to reliably prevent the uneven concentration of the electrolyte from occurring. Moreover, it is possible to more reliably prevent the coalesced particles once formed from collapsing while efficiently coalescing the dispersoid. As a result, coalesced particles with small variations in shape and particle size among the particles can be obtained efficiently.

The blade tip speed of the stirring blade is preferably from 0.1 m / second to 10 m / second, more preferably from 0.2 m / second to 8 m / second, and from 0.2 m / second to 6 m / second. More preferably, it is as follows. When the blade tip speed is a value within the above range, the added electrolyte can be uniformly dispersed and dissolved, and the occurrence of uneven concentration of the electrolyte can be reliably prevented. In addition, it is possible to more reliably prevent the coalesced particles once formed from collapsing while more efficiently coalescing the dispersoid.
The average particle size of the obtained coalesced particles is preferably 0.5 μm or more and 5 μm or less, and more preferably 1.5 μm or more and 4 μm or less. Thereby, the particle diameter of the toner particles finally obtained can be more appropriately set to be appropriate.

[Organic solvent removal step]
Thereafter, the organic solvent contained in the O / W emulsion (particularly in the dispersoid) is removed. As a result, a dispersion liquid in which toner particles are dispersed in an aqueous dispersion medium (aqueous dispersion liquid) is obtained.
The removal of the organic solvent may be performed by any method, but can be performed, for example, under reduced pressure. Thereby, it is possible to efficiently remove the organic solvent while sufficiently preventing the modification of the constituent material such as the resin material.

Moreover, it is preferable that the process temperature in this process is temperature lower than the glass transition point (Tg) of the resin material which comprises coalesced particle.
Moreover, you may perform this process in the state which added the antifoamer to the O / W emulsion (dispersion). Thereby, an organic solvent can be removed efficiently.
Antifoaming agents include, for example, mineral oil-based antifoaming agents, polyether-based antifoaming agents, silicone-based antifoaming agents, lower alcohols, higher alcohols, fats and oils, fatty acids, fatty acid esters, phosphoric acid Esters can be used.

The amount of the antifoaming agent is not particularly limited, but it is preferably 20 ppm or more and 300 ppm or less, and preferably 30 ppm or more and 100 ppm or less in terms of weight ratio with respect to the solid content contained in the O / W emulsion. More preferred.
In this step, at least a part of the aqueous liquid may be removed together with the organic solvent.
In this step, it is not always necessary to remove all of the organic solvent (the total amount of the organic solvent contained in the dispersion). Even in such a case, the remaining organic solvent can be sufficiently removed in the steps described later.

[Washing process]
Next, the toner particles formed as described above are washed.
By performing this step, even when an organic solvent or the like is contained as an impurity, these can be efficiently removed. Moreover, by performing this process, the electrolyte, basic substance, acidic substance, and salt generated by the acid-base reaction used in the above-described process can be efficiently removed. As a result, the amount of impurities (such as the amount of volatile organic compound (TVOC)) in the finally obtained toner particles can be made particularly small.

This step can be performed, for example, by separating the toner particles by solid-liquid separation (separation from the aqueous liquid), and then redispersing the solid content (toner particles) in the aqueous liquid (aqueous dispersion medium). it can. The solid-liquid separation and the redispersion of the solid in water may be repeated a plurality of times. The washing is preferably performed until the conductivity of the supernatant of the dispersion (slurry) obtained by redispersing the solid content (toner particles) in the aqueous liquid (aqueous dispersion medium) is 20 μS / cm or less.
In addition, it is preferable to perform this process on conditions that a toner particle will not be in a dry state. Thereby, aggregation of toner particles can be prevented more reliably.

[Drying process]
Thereafter, a drying process can be performed to obtain a toner as a powder (an aggregate of dry toner particles). By performing such a process, the water content in the toner particles can be surely made sufficiently low, and the storage stability and characteristic stability of the toner can be made particularly excellent.
The drying step can be performed using, for example, a vacuum dryer (for example, ribocorn (manufactured by Okawara Seisakusho), nauter (manufactured by Hosokawa Micron) etc.), fluidized bed dryer (manufactured by Okawara Seisakusho), etc.

≪Toner≫
Next, the toner of the present invention manufactured using the above method (the manufacturing method of the present invention) will be described.
The toner produced using the method as described above contains a large number of toner particles, and the toner particles are composed of a resin material, a colorant, and kaolinite. The variation in charging characteristics among toner particles is small, and the cleaning characteristics are also excellent.

  The average particle size of the toner particles is preferably from 0.5 μm to 5.0 μm, more preferably from 0.8 μm to 4.0 μm, and even more preferably from 1.0 μm to 3.5 μm. . When the average particle diameter of the toner particles is within the above range, the toner particles can be prevented from unintentionally agglomerating during storage and the like, and variations in characteristics among the toner particles can be reduced. Thus, the resolution of the toner image formed can be made sufficiently high. In the present invention, the “average particle diameter” means a volume-based average particle diameter.

The average circularity of the toner particles is preferably from 0.910 to 0.965, and more preferably from 0.940 to 0.965. Thereby, the variation in charging characteristics among toner particles can be made smaller, and the cleaning characteristics can be made particularly excellent. In the present invention, “circularity” refers to the circumference of a projected image of toner particles to be measured as L ₁ [μm], and the circumference of a perfect circle having an area equal to the area of the projected image of toner particles as L ₁ . _{When 0} [μm], it means a value represented by L ₀ / L ₁ . The circularity of the toner particles can be determined using a flow type particle image analyzer (eg, Sysmex Corporation: FPIA-3000, FPIA-3000S, Toa Medical Electronics: FPIP-1000).

  The softening point of the resin material constituting the toner particles is preferably 50 ° C. or higher and 190 ° C. or lower, more preferably 55 ° C. or higher and 170 ° C. or lower, and further preferably 60 ° C. or higher and 160 ° C. or lower. Thereby, it is possible to achieve both higher toner fixing characteristics and heat resistant storage stability. In the present invention, the softening point refers to a measurement condition in a Koka type flow tester (manufactured by Shimadzu Corporation): a temperature increase rate: 5 ° C./min, and a softening start temperature defined by a die hole diameter of 1.0 mm. Point to.

The content of the resin material in the toner is preferably 65 wt% or more and 95 wt% or less, more preferably 70 wt% or more and 95 wt% or less, and further preferably 75 wt% or more and 95 wt% or less. Thereby, it is possible to achieve both higher toner fixing characteristics and heat resistant storage stability.
The content of the colorant in the toner is preferably 5 wt% or more and 25 wt% or less, more preferably 5 wt% or more and 20 wt% or less, and further preferably 5 wt% or more and 18 wt% or less. Thereby, it is possible to form a visible image (toner image) having a sufficient density while sufficiently fixing the toner to the recording medium (adhesion).

The content of kaolinite in the toner is not particularly limited, but is preferably 0.2 wt% or more and 5.0 wt% or less, and more preferably 0.5 wt% or more and 3.0 wt% or less. When the kaolinite content is within the above range, the above-described effects can be more effectively exhibited while sufficiently fixing the toner to the recording medium.
When the toner contains a wax, the content of the wax in the toner is not particularly limited, but is preferably 1.0 wt% or more and 15.0 wt% or less, and is 1.0 wt% or more and 10.0 wt% or less. Is more preferable. Thereby, the effect by including the above wax is exhibited more notably.

<< Image forming apparatus, image forming method >>
Next, an image forming method and an image forming method using the toner of the present invention will be described.
The image forming method according to the present embodiment forms a toner image on a recording medium through a charging step, an exposure step, a development step, a transfer step, and a fixing step.
First, an image forming apparatus to which the image forming method using the toner of the present invention as described above is applied will be described.
FIG. 2 is a schematic cross-sectional view showing an example of the overall configuration of an image forming apparatus to which the toner of the present invention is applied.

  The image forming apparatus 10 of the present embodiment shown in FIG. 2 records an image on a recording medium mainly by a series of image forming processes including exposure, development, transfer, and fixing. As shown in FIG. 2, such an image forming apparatus 10 has a photosensitive drum (latent image carrier) 20 that carries an electrostatic latent image and rotates in the direction of the arrow in the drawing, and along the rotation direction. A charging unit 30, an exposure unit 40, a developing unit 50, an intermediate transfer member 61, and a cleaning unit 75 are sequentially arranged. In addition, the image forming apparatus 10 is provided with a paper feed tray 82 that accommodates a recording medium P such as paper at the bottom in FIG. The transfer body 61 and the fixing device 90 are sequentially arranged along the conveyance direction of the recording medium P. Further, when forming an image on both sides of the recording medium, the image forming apparatus 10 reverses the recording medium P fixed on one side by the fixing device 90 and returns it to the secondary transfer position described later. The conveyance part 88 for making it do is provided.

The photosensitive drum 20 has a cylindrical conductive substrate (not shown) and a photosensitive layer (not shown) formed on the outer peripheral surface thereof, and can rotate around the axis in the direction of the arrow in FIG. It has become.
The charging unit 30 is a device for uniformly charging the surface of the photosensitive drum 20 by corona charging or the like.
The exposure unit 40 receives image information from a host computer such as a personal computer (not shown), and forms an electrostatic latent image by irradiating a laser on the uniformly charged photosensitive drum 20 in accordance with the image information. It is a device to do.

  The developing unit 50 includes four developing devices, a black developing device 51, a magenta developing device 52, a cyan developing device 53, and a yellow developing device 54. These developing devices are converted into latent images on the photosensitive drum 20. It is an apparatus that visualizes the latent image as a toner image, selectively used correspondingly. The black developing device 51 uses black (K) toner, the magenta developing device 52 uses magenta (M) toner, the cyan developing device 53 uses cyan (C) toner, and the yellow developing device 54 uses yellow (Y) toner. As described above, since the toner of the present invention has a small variation in charging characteristics among toner particles, a desired toner image can be reliably formed.

  In the case where a plurality of types of toner are used as in the present embodiment, the present invention may be applied to at least one type of toner, but the present invention is preferably applied to a plurality of types of toner, More preferably, the present invention is applied to toner. As a result, the effects as described above are more remarkably exhibited, the variation in charging characteristics between the toners corresponding to the respective colors can be more effectively suppressed, and the bias setting in the image forming apparatus can be easily performed. it can. Further, the development efficiency for the toner corresponding to each color can be made more uniform.

  The YMCK developing unit 50 in this embodiment is rotatable so that the above-described four developing devices 51, 52, 53, and 54 are selectively opposed to the photosensitive drum 20. Specifically, in this YMCK developing unit 50, four developing devices 51, 52, 53, and 54 are respectively held by four holding portions 55a, 55b, 55c, and 55d of a holding body 55 that can rotate around a shaft 50a. The four developing devices 51, 52, 53, and 54 are selectively opposed to the photosensitive drum 20 while maintaining the relative positional relationship by the rotation of the holder 55. The developing devices 51, 52, 53, and 54 will be described later in detail.

The intermediate transfer member 61 has an endless belt-like intermediate transfer belt 70, and this intermediate transfer belt 70 is stretched by a primary transfer roller 60, a driven roller 72, and a driving roller 71, and is rotated by the rotation of the driving roller 71. 2 is driven to rotate in the direction of the arrow shown in FIG.
The primary transfer roller 60 is a device for transferring a single color toner image formed on the photosensitive drum 20 to the intermediate transfer belt 70.

  On the intermediate transfer belt 70, a toner image of at least one of black, magenta, cyan, and yellow is carried. For example, when a full-color image is formed, four color toner images of black, magenta, cyan, and yellow are sequentially formed. The toner images are transferred to form a full-color toner image. In the present embodiment, the driving roller 71 also functions as a backup roller for the secondary transfer roller 80 described later. Further, the primary transfer roller 60, the drive roller 71, and the driven roller 72 are supported by the base 73.

The secondary transfer roller 80 is a device for transferring a single color or full color toner image formed on the intermediate transfer belt 70 to a recording medium P such as paper, film, or cloth.
The fixing device 90 is a device for fixing the toner image to the recording medium P by heating and pressurizing the recording medium P that has received the transfer of the toner image.
The cleaning unit 75 has a rubber cleaning blade 76 that contacts the surface of the photosensitive drum 20 between the primary transfer roller 60 and the charging unit 30, and a toner image is transferred onto the intermediate transfer belt 70 by the primary transfer roller 60. Then, the toner remaining on the photosensitive drum 20 is scraped off by the cleaning blade 76 and removed. As described above, since the toner of the present invention is excellent in cleaning characteristics, the toner remaining on the photosensitive drum 20 is surely scraped off and removed by the cleaning blade 76, so that the remaining toner onto the recording medium. It is possible to more reliably prevent adverse effects on the formed image.

  The conveyance unit 88 reverses the front and back of the conveyance roller pair 88A and 88B for nipping and conveying the recording medium P fixed on one surface by the fixing device 90, and the recording medium P conveyed by the conveyance roller pair 88A and 88B. And a conveyance path 88 </ b> C for guiding the registration roller 86. As a result, when an image is formed on both sides of the recording medium, the recording medium P fixed on one side by the fixing device 90 is reversed and returned to the secondary transfer roller 80.

Next, the operation of the image forming apparatus 10 configured as described above will be described.
First, in response to a command from a host computer (not shown), the photosensitive drum 20, the developing roller (not shown) provided in the developing unit 50, and the intermediate transfer belt 70 start to rotate. The photosensitive drum 20 is sequentially charged by the charging unit 30 while being rotated (charging process).

The charged area of the photosensitive drum 20 reaches an exposure position as the photosensitive drum 20 rotates, and a latent image corresponding to image information of the first color, for example, yellow Y, is formed in the area by the exposure unit 40. (Exposure process).
The latent image formed on the photosensitive drum 20 reaches the developing position as the photosensitive drum 20 rotates, and is developed with yellow toner by the yellow developing device 54 (developing process). As a result, a yellow toner image is formed on the photosensitive drum 20. At this time, in the YMCK developing unit 50, the yellow developing device 54 faces the photosensitive drum 20 at the developing position.

  The yellow toner image formed on the photosensitive drum 20 reaches the primary transfer position (that is, the portion where the photosensitive drum 20 and the primary transfer roller 60 face each other) as the photosensitive drum 20 rotates, and is intermediated by the primary transfer roller 60. Transfer (primary transfer) is performed on the transfer belt 70 (primary transfer step). At this time, a primary transfer voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the primary transfer roller 60. During this time, the secondary transfer roller 80 is separated from the intermediate transfer belt 70.

The same processing as described above is repeatedly executed for the second color, the third color, and the fourth color, so that the toner images of the respective colors corresponding to the respective image signals are transferred onto the intermediate transfer belt 70 in an overlapping manner. The As a result, a full-color toner image is formed on the intermediate transfer belt 70.
On the other hand, the recording medium P is conveyed from the paper feed tray 82 to the secondary transfer roller 80 by the paper feed roller 84 and the registration roller 86.

The full-color toner image formed on the intermediate transfer belt 70 reaches the secondary transfer position (that is, the portion where the secondary transfer roller 80 and the driving roller 71 face each other) as the intermediate transfer belt 70 rotates, and the secondary transfer. Transfer (secondary transfer) to the recording medium P is performed by the roller 80 (secondary transfer step). At this time, the secondary transfer roller 80 is pressed against the intermediate transfer belt 70 and a secondary transfer voltage (secondary transfer bias) is applied.
The full-color toner image transferred to the recording medium P is heated and pressurized by the fixing device 90 and fixed (fused) to the recording medium P (fixing step).
Thereafter, the recording medium P is discharged to the outside of the image forming apparatus 10 by the paper discharge roller pair 87.

On the other hand, after the primary transfer position has elapsed, the toner adhering to the surface of the photosensitive drum 20 is scraped off by the cleaning blade 76 of the cleaning unit 75 to prepare for charging to form the next latent image. The toner that has been scraped off is collected by a residual toner collecting section in the cleaning unit 75.
In the case of forming an image on both sides of the recording medium, the recording medium P fixed on one side by the fixing device 90 is once sandwiched by the discharge roller pair 87, and then the discharge roller pair 87 is driven in reverse. By driving the conveyance roller pair 88A and 88B, the recording medium P is turned upside down through the conveyance path 88C and returned to the secondary transfer roller 80, and an image is printed on the other surface of the recording medium P by the same operation as described above. Form.

Here, based on the drawings, a developing device 54 as an example of a developing device to which the toner of the present invention is applied will be described in detail. The developing devices 51, 52, and 53 are the same as the developing device 54 except that the color of the toner to be used is different, and thus description thereof is omitted.
FIG. 3 is a perspective view showing a developing device provided in the image forming apparatus shown in FIG. 2, and FIG. 4 is a schematic sectional view showing a schematic configuration of the developing device shown in FIG.

As shown in FIG. 4, the developing device 54 includes a housing 2 in which a toner containing portion 21 that contains toner T (toner of the present invention) that is a developer is formed, a developing roller 3 that carries the toner T, and a developing roller. 3 includes a toner supply roller 4 that supplies toner T to 3 and a regulating blade 5 that regulates the layer thickness of the toner T carried on the developing roller 3.
The housing 2 stores the toner T in a toner storage portion 21 formed as an internal space thereof.

  The housing 2 opens to the right in FIG. 3, and the toner supply roller 4 and the developing roller 3 are rotatably supported in the vicinity of the opening. A regulating blade 5 is attached to the housing 2. Further, a seal member 6 for preventing leakage of toner from between the housing 2 and the developing roller 3 in the opening is attached to the housing 2.

  The developing roller 3 conveys the toner T to a developing position (hereinafter simply referred to as “developing position”) between the developing roller 3 and the photosensitive drum 20 while carrying the toner T on its outer peripheral surface. Further, the developing roller 3 has a cylindrical shape and is rotatable around its axis. In the present embodiment, the developing roller 3 rotates in a direction opposite to the rotation direction of the photosensitive drum 20. Further, as shown in FIG. 3, a tape-like spacer 39 is provided on the outer peripheral surface of both end portions of the developing roller 3 over the entire periphery. The spacer 39 is pressed against the image non-carrying surface of the photosensitive drum 20 to form a developing gap g between the developing roller 3 and the photosensitive drum 20. This development gap g can be adjusted to a desired size by the thickness of the spacer 39. The constituent material of the spacer 39 is not particularly limited, but it is preferable to use a material having elasticity and higher hygroscopicity than the developing roller 3. The spacer 39 and the developing roller 3 are preferably fixed via an elastic adhesive.

  In this way, the developing roller 3 and the photosensitive drum 20 face each other in a non-contact state with a minute gap g. Then, by applying an AC bias (alternating electric field) as a developing bias voltage between the developing roller 3 and the photosensitive drum 20, the toner T is caused to fly from the developing roller 3 to the photosensitive drum 20, and on the photosensitive drum 20. The latent image is developed as a toner image. That is, in this embodiment, so-called non-contact jumping development is performed. In non-contact jumping development, the toner T flies and reciprocates between the developing roller 3 and the photosensitive drum 20 as the AC bias (developing bias voltage) changes.

  The toner supply roller 4 supplies the toner T from the toner storage unit 21 via the guide member to the developing roller 3. The toner supply roller 4 includes a main body 41 having a cylindrical shape or a columnar shape, and an elastic porous body layer 42 provided on the main body 41. The elastic porous body layer 42 is made of polyurethane foam or the like, and is in pressure contact with the developing roller 3 while being elastically deformed. In the present embodiment, the toner supply roller 4 rotates in a direction opposite to the rotation direction of the developing roller 3. The toner supply roller 4 not only has a function of supplying the toner T to the developing roller 3 but also has a function of peeling off the toner T remaining on the developing roller 3 after development from the developing roller 3. . A voltage equivalent to the developing bias voltage applied to the developing roller 3 is also applied to the toner supply roller 4.

The regulating blade 5 regulates the layer thickness of the toner T carried on the developing roller 3 and applies a charge to the toner T by frictional charging during the regulation. The regulating blade 5 also functions as a seal member that seals between the housing 2 and the developing roller 3.
The regulating blade 5 includes an elastic body 56 that is abutted along the axial direction of the developing roller 3 and a support member 57 that supports the elastic body 56. The elastic body 56 is made of, for example, silicon rubber, urethane rubber or the like as a main material. The support member 57 is a sheet-like thin plate having a spring property (elasticity) such as phosphor bronze or stainless steel, and has a function of biasing the elastic body 56 to the developing roller 3.

In the present embodiment, the regulating blade 5 is disposed so that the tip (free end) thereof faces the upstream side in the rotation direction of the developing roller 3 and is in a so-called counter contact. Further, the developing device 54 of the present embodiment is configured to drop the excess toner on the developing roller 3 downward by the regulating blade 5 and return it to the toner storage unit 21.
As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to the above.

For example, the manufacturing method of this invention should just have a resin solution preparation process, an O / W emulsion preparation process, a coalescing process, and an organic solvent removal process. It may be omitted.
Moreover, the manufacturing method of this invention may have processes other than the said process. For example, you may have the process of providing an external additive etc. after particle | grain formation.

Further, the toner of the present invention is not limited to that applied to the image forming apparatus as described above.
In the above-described embodiment, the case where the toner of the present invention is a dry toner has been representatively described. However, the toner of the present invention may be applied to a toner for a liquid developer.
In addition, each unit constituting the image forming apparatus can be replaced with an arbitrary configuration that can exhibit the same function. Moreover, arbitrary components may be added.

[1] Production of Toner A toner was produced as follows. About the process in which temperature is not described, it performed at room temperature (25 degreeC).
Example 1
[Dispersion preparation process]
(Preparation of colorant master)
First, polyester resin as a resin material (acid value: 10 mg KOH / g, glass transition point (Tg): 55 ° C., softening point: 107 ° C.): 50 parts by weight, and cyan pigment (Daiichi Seika Co., Ltd.) as a colorant Pigment Blue 15: 3): 50 parts by weight were prepared and mixed using a 20 L Henschel mixer to obtain a raw material for toner production.
Next, this raw material (mixture) was kneaded using a twin-screw kneading extruder. The kneaded product extruded from the extrusion port of the biaxial kneading extruder was cooled.
The kneaded material cooled as described above was coarsely pulverized to obtain a colorant master batch having an average particle size of 1.0 mm or less. A hammer mill was used for coarse pulverization of the kneaded product.

(Preparation of wax master solution)
MEK (methyl ethyl ketone) 50% solution of the polyester resin: 100 parts by weight, carnauba wax (TOWAX-125 manufactured by Toa Kasei Co., Ltd.): 16.7 parts by weight, wax dispersant (Disperbyk-108 manufactured by BYK Chemie): 1.7 weights Part, MEK: 80 parts by weight were dispersed with a bead mill disperser (Star Mill DMR110 type, manufactured by Ashizawa Finetech Co., Ltd.) to obtain a wax dispersion.

(Resin solution preparation process)
The above colorant masterbatch: 82.5 parts by weight of methyl ethyl ketone: 148.4 parts by weight and the polyester resin: 145.8 parts by weight of a high-speed disperser (manufactured by Primix, TK Robotics / TK Homo Disperser) 2.5 type wing) and mixed with Neogen SC-F as an emulsifier (Daiichi Kogyo Seiyaku Co., Ltd.): 0.7 parts by weight, kaolinite: 5.5 parts by weight, wax master solution: 117.9 parts by weight Was added to prepare a resin solution.
In this solution, the pigment and kaolinite were uniformly finely dispersed. Further, as kaolinite, one having Al ₂ Si ₂ O ₅ (OH) ₄ as a basic composition and subjected to a surface treatment with a quaternary amine (tetrahexylammonium) was used. The average particle size of kaolinite was 134 nm.

[O / W emulsion preparation process]
Next, 25 parts by weight of 1N ammonia water was added to the resin solution in the vessel, and the stirring blade was mixed with a high-speed disperser (Primics Co., Ltd., TK Robotics / TK homodisper type 2.5 blade). 150 parts by weight while stirring at a blade tip speed of 7.5 m / s, adjusting the temperature of the solution in the flask to 25 ° C., and then stirring at a blade tip speed of 14.7 m / s. O / W in which the dispersoid containing the resin material was dispersed via the W / O emulsion by adding 100 parts by weight of deionized water while continuing stirring. An emulsion was obtained.

[Joint process]
Next, the W / O emulsion was transferred to a stirring vessel having a Max blend blade, and the temperature of the W / O emulsion was adjusted to 25 ° C. while stirring at a blade tip speed of 1.0 m / s. .
Next, while maintaining the same temperature and stirring conditions, 119 parts by weight of a 5.0% aqueous sodium sulfate solution was added dropwise to coalesce the dispersoids to form coalesced particles. After the dropping, stirring was continued until the 50% volume particle diameter Dv (50) [μm] of the coalesced particles grew to 3.3 μm. When the Dv (50) of the coalesced particles reached 3.3 μm, 200 parts by weight of deionized water was added to complete the coalescence.

[Organic solvent removal step]
Next, the W / O emulsion containing the coalesced particles was placed in a reduced pressure environment, and the organic solvent was distilled off until the solid content was 23 wt% to obtain a toner particle slurry (dispersion).
[Washing process]
Next, the slurry (dispersion) was subjected to solid-liquid separation, and further washed again by redispersion in water (reslurry) and solid-liquid separation. The washing treatment was performed until the conductivity of the supernatant of the slurry became 20 μS / cm or less.
Thereafter, a wet cake of toner particles (toner particle cake) was obtained by suction filtration.

[Drying process]
Thereafter, the obtained wet cake was dried using a vacuum dryer to obtain toner as a powder (aggregate of toner particles in a dry state).
The Dv (50) of the toner particles was 3.1 μm. The 50% volume particle diameter Dv (50) [μm] of the obtained toner particles was measured with Microtrac MT-3000 (manufactured by Nikkiso Co., Ltd.). The average circularity of the toner particles was 0.962. The circularity of the toner particles was determined by measurement using a flow type particle image analyzer (for example, made by Sysmex Corporation: FPIA-3000. Further, it was obtained in each of Examples and Comparative Examples described below. Similarly, the average particle diameter and average circularity were determined for the particles.

Further, instead of cyan pigment, magenta pigment: Pigment Red 238 (manufactured by Sanyo Dye), yellow pigment: Pigment Yellow 180 (manufactured by Clariant), black pigment: carbon black (printex L, manufactured by Degussa) In addition, a magenta toner, a yellow toner, and a black toner were produced in the same manner as described above except that the respective changes were made.
(Examples 2-9)
Toners corresponding to the respective colors were produced in the same manner as in Example 1 except that the conditions of the materials used for the production of the toner were changed as shown in Table 1.

(Comparative Example 1)
A toner was produced in the same manner as in the above example except that kaolinite was not used in the resin solution preparation step.
(Comparative Example 2)
First, a polyester resin as a resin material (acid value: 10 mgKOH / g, glass transition point (Tg): 55 ° C., softening point: 107 ° C.): and a cyan pigment as a colorant (manufactured by Dainichi Seika Co., Ltd., Pigment) Blue 15: 3): and kaolinite were mixed, then kneaded and kneaded using a twin-screw kneading extruder. The kneaded product extruded from the extrusion port of the biaxial kneading extruder was cooled.

The kaolinite used was Al ₂ Si ₂ O ₅ (OH) ₄ as a basic composition and surface-treated with a quaternary amine (tetrahexylammonium). The average particle size of kaolinite was 134 nm.
The kneaded material cooled as described above was coarsely pulverized (average particle size: 1 to 2 mm), and then finely pulverized to obtain a toner. A hammer mill was used for coarse pulverization of the kneaded product, and a jet mill (200 AFG, manufactured by Hosokawa Micron Corporation) was used for fine pulverization. The fine pulverization was performed at a pulverization air pressure: 500 [kPa] and a rotor rotational speed: 7000 [rpm].

  Table 1 shows the toner composition, the average particle diameter of the toner particles, and the average circularity for each of the above Examples and Comparative Examples. For each example and comparative example 1, the content of each toner component in all the components of the toner contained in the resin solution is the content of the component in the finally obtained toner. It was the same. In the table, the polyester resin (acid value: 10 mgKOH / g, glass transition point (Tg): 55 ° C., softening point: 107 ° C.) is shown as PES, and styrene-acrylate copolymer is shown as ST-AC. .

[2] Evaluation Each toner obtained as described above was evaluated as follows.
[2.1] Development efficiency The toner obtained in each of the above examples and comparative examples is put in a color printer cartridge of the image forming apparatus as shown in FIGS. The toner obtained in each comparative example was supported. Next, the surface potential of the developing roller is set to −300 V, the surface potential of the photosensitive member is uniformly charged to −500 V, the photosensitive drum is exposed, the charging of the surface of the photosensitive drum is attenuated, and the surface potential is set to −50 V. . After the toner carried on the developing roller passed between the photosensitive drum and the developing roller, the toner on the developing roller and the toner on the photosensitive drum were collected with a tape. Each tape used for sampling was affixed on a recording paper, and the density of each toner was measured. After the measurement, the value obtained by dividing the density of the toner collected on the photosensitive drum by the sum of the density of the toner collected on the photosensitive drum and the density of the toner collected on the developing roller is multiplied by 100. The development efficiency was obtained and evaluated according to the following four-stage criteria. In the table, the evaluation of the average value for the four color toners is shown.
A: The development efficiency is 96% or more, and the development efficiency is particularly excellent.
B: The development efficiency is 90% or more and less than 96%, and the development efficiency is excellent.
C: The development efficiency is 80% or more and less than 90%, and there is no practical problem.
D: The development efficiency is less than 80% and the development efficiency is inferior.

[2.2] Charging characteristics (uniformity of charge amount)
The toner obtained in each example and each comparative example was put into the cartridge of the image forming apparatus described above.
The charge amount of the toner regulated by the regulating blade of the developing device and conveyed to the photosensitive member was evaluated by analyzing the toner on the developing roller. The charge amount was measured by an E-SPART analyzer manufactured by Hosokawa Micron Corporation. The measurement conditions were a suction flow rate of 0.2 liters / minute, a dust collection air flow rate of 0.6 liters / minute, a blowing nitrogen gas pressure of 0.02 MPa, and the charge amount (Q / m) for each toner was measured. The charge amount distribution was obtained with a toner count of 3000.

The uniformity of the toner charge amount is obtained by dividing the maximum charge amount (Q ₁ / m ₁ ) and the total toner charge amount measured by the measurement count (number) in the number distribution of the charge amount per toner. The smaller the absolute value of the difference from the value (Q ₂ / m ₂ ), the more uniform the charge amount distribution, and the larger the absolute value, the more nonuniform. The evaluation was performed based on the following five-stage criteria. In the table, the average value of the four color toners is shown.
A: The absolute value of the difference is 0.8 or less.
B: The absolute value of the difference is greater than 0.8 and 1.0 or less.
C: The absolute value of the difference is larger than 1.0 and 1.5 or less.
D: The absolute value of the difference is greater than 1.5 and 2.0 or less.
E: The absolute value of the difference is larger than 2.0.

[2.3] Cleanability Using the image forming apparatus described above, a predetermined pattern was continuously printed on 8000 sheets, and the cleanability was evaluated according to the following four-stage criteria.
A: No wiping residue on the surface of the photoreceptor is observed at all.
B: Almost no wiping residue on the surface of the photoreceptor is observed.
C: A slight wiping residue on the surface of the photoreceptor is observed.
D: Remaining wiping on the surface of the photoreceptor is remarkably recognized.
These results are shown in Table 2.

  As is apparent from Table 2, the toner of the present invention had a small variation in charging characteristics between toner particles and was excellent in cleaning properties. The toner of the present invention was also excellent in development efficiency. On the other hand, in each comparative example, a satisfactory result was not obtained.

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 3 ... Developing roller 6 ... Sealing member 2 ... Housing 4 ... Toner supply roller 5 ... Restricting blade 56 ... Elastic body 57 ... Supporting member 20 ... Photosensitive drum 21 ... Toner accommodating part 30 ... Charging unit 39 ... Spacer 40 ... Exposure unit 41 ... Main body 42 ... Elastic porous body layer 50 ... Developing unit 50a ... Shaft 51 ... Black developing device 52 ... Magenta developing device 53 ... Cyan developing device 54 ... Yellow developing device 55 ... Holding body 55a-55d ... Holding unit DESCRIPTION OF SYMBOLS 60 ... Primary transfer roller 61 ... Intermediate transfer body 70 ... Intermediate transfer belt 71 ... Drive roller 72 ... Drive roller 73 ... Substrate 75 ... Cleaning unit 76 ... Cleaning blade 80 ... Secondary transfer roller 82 ... Paper feed tray 84 ... Paper feed roller 86 ... Register Roller 87 ... Discharge roller pair 88 ... Conveying unit 88A, 88B ... Conveying roller pair 88C ... Conveying path 90 ... Fixing device P ... Recording medium T ... Toner S10 ... Resin solution preparation step S20 ... O / W emulsion preparation step S30 ... Composite One step S40 ... Organic solvent removal step S50 ... Washing step S60 ... Drying step

Claims (7)

A resin solution preparation step of preparing a resin solution comprising a resin material, a colorant, and kaolinite, wherein at least a part of the resin material is dissolved in an organic solvent;
An O / W emulsion preparation step of preparing an O / W emulsion via a W / O emulsion by adding an aqueous liquid to the resin solution;
A coalescence step of coalescing dispersoids contained in the O / W emulsion to obtain coalesced particles;
An organic solvent removing step of removing the organic solvent contained in the coalesced particles.   The toner production method according to claim 1, wherein the kaolinite has an average particle size of 80 nm to 500 nm.   3. The method for producing a toner according to claim 1, wherein the content of the kaolinite in all the components of the toner contained in the resin solution is 0.2 wt% or more and 5.0 wt% or less.   The method for producing a toner according to claim 1, wherein the kaolinite is subjected to a surface treatment with a quaternary amine.   The toner manufacturing method according to claim 1, wherein a polyester resin is used as the resin material.   A toner produced using the method according to claim 1.   The toner according to claim 6, wherein the toner particles have an average circularity of 0.910 to 0.965.

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