JP2005078006A - Method for manufacturing toner particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing toner particles by using a stirring device having high shear force by which the manufacture cost can be suppressed while no adverse influence is given to the quality of the toner, and preferably, the deposition of a substance on the stirring device is prevented. <P>SOLUTION: The method for manufacturing toner particles includes a step of dispersing at least a polymerizable monomer in a liquid dispersion medium which is substantially incompatible with the polymerizable monomer by using a stirring device which has high shear force and which is connected to a rotating stirring shaft and disposed in a dispersion chamber, and the toner particles are manufactured by polymerizing the polymerizable monomer dispersed in the above step. The stirring device used is disposed in a position where the stirring device with the stirring shaft in the dispersion chamber is included in the liquid phase of a liquid phase and a gas phase formed when at least the liquid dispersion medium and the polymerizable monomer are housed in the dispersion chamber. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing toner particles contained in toner used in an image forming method such as an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or a toner jet recording method.

  Conventionally, in electrophotography, an electric latent image is formed on a photoreceptor by various means, and then the latent image is developed with toner, and the toner image is transferred onto a transfer material such as paper as necessary. Thereafter, the toner image is fixed by heating, pressure, heating pressure or solvent vapor (see, for example, Non-Patent Document 1).

  As a method for producing toner particles contained in the toner used in such an electrophotographic method, a toner by various polymerization methods such as an emulsion polymerization method and a production method thereof have been proposed, including a toner by a suspension polymerization method. . For example, in the suspension polymerization method, a colorant is dispersed in a polymerizable monomer to obtain a fine particle monomer mixture, and then a polymerization initiator, and if necessary, a crosslinking agent, a charge control agent, and other additives. Is uniformly dissolved or dispersed into a polymerizable monomer composition, and then the polymerizable monomer composition is stirred in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase having an appropriate high shear force. A method of obtaining toner particles having a desired particle size by atomizing and granulating using an apparatus and simultaneously polymerizing the obtained fine particles is known (for example, see Patent Document 1).

  In the emulsion polymerization method, for example, a monomer composition containing a polymerizable monomer, a polymerization initiator, a surfactant, and, if necessary, a crosslinking agent, a chain transfer agent, and other additives in an aqueous medium. Are dispersed using a suitable high shearing stirrer, and at the same time, a polymerization reaction is carried out to obtain emulsified resin particles having a desired particle size. Further, the mixture is uniformly dispersed in an aqueous medium containing a colorant, a dispersion aid, a charge control agent, and the like using a bead mill or a stirrer having a high shear force, and then associated with the above-described emulsified resin particles (aggregation and fusion). A toner particle having a desired particle size is known (for example, see Patent Document 2).

  Since these methods do not require brittleness of the toner particles, a soft resin can be used as a material, and there is no exposure of the colorant to the surface of the toner particles, and uniform triboelectric chargeability is achieved. Since the toner particles are obtained, the particle size distribution of the obtained toner particles is relatively sharp, the classification step can be omitted, or even if classified, the toner particles can be obtained in a high yield, and Since a large amount of plural kinds of low softening point substances can be encapsulated in the toner particles as a release agent, it is excellent from the viewpoint of obtaining toner particles having excellent offset resistance.

  In the above-described conventional method, as the stirring device having the high shearing force, the stirring blade provided at the tip of the stirring shaft extending from the top to the bottom of the dispersion vessel and the inside of the dispersion vessel are opened. At the same time, a stirring device that forms a stirring chamber containing the stirring blades, is provided stationary with respect to the stirring shaft, and has a screen having a liquid passage hole is generally used.

  However, when the above-described stirring device having a high shearing force is used, heat is generated from the stirring device and the stirring shaft by high-speed stirring. This heat generation may cause a thermal influence on the polymerizable monomer composition in the dispersion container and cause a problem in desired dispersion. This inconvenience of dispersion leads to broadening of the particle size distribution of the obtained toner particles, which may adversely affect the classification yield.

In addition, the heat generation is caused by polymerizing the polymerizable monomer composition attached to the stirring device or the stirring shaft,
May cause strong deposits. When this deposit grows, it may be mixed into the product or make the movable part of the stirring device immovable. The effect of this deposit can be avoided by periodically removing the deposit, but this periodic maintenance must be performed with the production line stopped, which increases production costs. ing. In particular, this deposit is likely to occur at the gas-liquid interface in the dispersion container. When deposits are generated at the gas-liquid interface, drying and baking occur due to heat generated by stirring, and the deposits tend to become stronger.

  In order to solve these problems, a method of cooling the agitation shaft by showering the above-described high shear force agitation device or forming a jacket around the agitation shaft is used. Although certain effects are obtained by these measures, the effects are limited, and the configuration of a stirrer including a stirrer and the like is complicated, resulting in an increase in equipment costs.

JP-A-8-305084 JP 2000-292773 A Electrophotographic Society, “Basics and Applications of Electrophotographic Technology”, Corona Co., Ltd., June 15, 1988, p. 46-79

  An object of the present invention is to provide a method for producing toner particles that solves the above-described problems. Specifically, an object of the present invention is to provide a method for producing toner particles that does not adversely affect the quality of the toner in the production of toner particles using a stirring device having a high shearing force.

  Furthermore, the object of the present invention is to suppress the production cost in the production of toner particles using a stirrer having a high shearing force by preventing the adhesion of deposits to the stirrer and reducing the apparatus maintenance cost. The object is to provide a method for producing toner particles.

  As a result of intensive studies to solve the above-described problems of the prior art, the present inventor has generated heat in the stirring device and the stirring shaft having high shearing force in the toner particle manufacturing method using the stirring device having high shearing force. The present inventors have found that the toner quality is affected and have reached the present invention. In particular, it has been found that the structure having a stirring shaft extending from the top of the dispersion container or the lid on the top of the dispersion container to the vicinity of the bottom of the dispersion container further generates heat from the stirring shaft and has a further influence on the quality of the toner. did. As a result, the inventors have found a method for minimizing the thermal influence given to the polymerizable monomer composition by heat generation by shortening the stirring shaft as much as possible, and have reached the present invention.

  Further, the present inventor has found that the long stirring shaft described above is related to the growth of deposits of the stirring device, and has invented a method for producing the toner particles. In particular, the growth of deposits often occurs at the gas-liquid interface formed at the interface between the liquid phase part existing in the dispersion vessel and the other gas phase part, and the stirring axis that generates heat is the gas-liquid interface. The present inventors have found a method for producing toner particles that do not exist in the present invention, and have reached the present invention.

  That is, the present invention relates to a method for producing toner particles having the following characteristics.

(1) At least a polymerizable monomer is provided in a dispersion vessel connected to a rotating stirring shaft in a liquid dispersion medium substantially incompatible with the polymerizable monomer, and provided with a high shearing force. In the method for producing toner particles, in which the polymerizable monomer dispersed in this step is polymerized to produce toner particles, and in the dispersing step, at least a liquid dispersion medium is polymerized. The liquid phase part of the liquid phase part and the gas phase part formed when the polymerizable monomer is accommodated in the dispersion container is provided at a position where the stirring shaft and the stirring device in the dispersion container are included. The toner particle manufacturing method is characterized by using a stirring device.
(2) The method for producing toner particles according to (1), wherein the liquid dispersion medium is an aqueous dispersion medium.
(3) The step of dispersing is a step of granulating by dispersing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in a liquid dispersion medium and granulating the composition. (1) A method for producing toner particles according to (2).
(4) The method for producing toner particles according to any one of (1) to (3), wherein the stirring device is provided at or near the bottom of the dispersion container.
(5) In the step of dispersing, (1) to ((1) to () are characterized in that a flow in the direction of being sucked into the stirring device from above the stirring device and ejected from the stirring device to the lower portion of the stirring device is formed in the liquid phase part. 4) The method for producing toner particles according to any one of 4).
(6) The stirrer has a stirring blade that rotates with the rotation of the stirring shaft, and a screen that forms a stirring chamber containing the stirring blade, and this screen is open toward the dispersion vessel. The method for producing toner particles according to any one of (1) to (5), wherein a stirring chamber is formed and liquid passage holes are formed in the wall surface of the stirring chamber.
(7) The method for producing toner particles according to (6), wherein the peripheral speed of the stirring blade is 10 m / s to 50 m / s.
(8) The stirring shaft is connected to the lower portion of the stirring blade, and the angle α formed by the axis of the stirring shaft and a straight line extending in the vertical direction is 60 ° or less. It is a manufacturing method of the toner particle of description.
(9) The dispersion container has a discharge valve for discharging at least the polymerizable monomer and the liquid dispersion medium, and the discharge valve is provided below the stirring blade (6) to ( The method for producing toner particles according to any one of 8).
(10) The method for producing toner particles according to any one of (1) to (9), wherein the toner particles having a core / shell structure are produced.
(11) The method for producing toner particles according to (10), wherein the main component of the core part of the core / shell structure is a low softening point substance having a melting point of 40 to 90 ° C.

  According to the present invention, it is possible to provide a method for producing toner particles that does not adversely affect the quality of toner in the production of toner particles using a stirring device having a high shearing force. Furthermore, according to the present invention, it is possible to provide a method for producing toner particles, which can prevent the adhering matter from adhering to the stirring device, and thereby can reduce the production cost.

  In the method for producing toner particles of the present invention, at least a polymerizable monomer is dispersed in a liquid dispersion medium substantially incompatible with the polymerizable monomer using a stirring device having a high shearing force. Including the step of

  In the dispersing step, at least the liquid dispersion medium and the polymerizable monomer are contained in the dispersion container in the liquid phase part formed between the liquid phase part and the gas phase part formed in the dispersion container. The stirring device having the high shearing force provided at a position where the stirring shaft and the stirring device are included is used.

The liquid dispersion medium is not particularly limited as long as it is substantially incompatible with the polymerizable monomer or the polymerizable monomer composition described below. As used herein, “substantially incompatible” means a polymerizable monomer or polymerizable monomer composition in which a particulate polymer is obtained when a polymerizable monomer is polymerized in a liquid dispersion medium. This indicates the degree of compatibility of the liquid dispersion medium with respect to the product, and the liquid dispersion medium does not necessarily have to be separated from the polymerizable monomer or polymerizable monomer composition. As such a liquid dispersion medium, one or two or more kinds of various known solvents and solutions are appropriately selected depending on the polymerizable monomer and the kind of components in the polymerizable monomer composition. .

  The stirrer having a high shearing force is not particularly limited as long as it is a device for stirring a liquid and exhibits a shearing action on the liquid to be stirred. As such a stirring device, for example, one member and the other member are provided close to each other, at least one of these members is movable, and the members move relatively in the counter direction. The stirring apparatus which has is mentioned. More specifically, such a stirring device has a stirring blade that rotates as the stirring shaft rotates, and a screen that forms a stirring chamber that contains the stirring blade, and this screen is disposed in the dispersion vessel. A stirring device that forms a stirring chamber that is open toward the surface and has a fluid passage hole that opens to the wall surface of the stirring chamber, or two or more stirring blades that are provided side by side or stacked and that rotate in the counter direction. And the like.

  Note that “having high shearing force” means toner particles when polymerized while dispersing the polymerizable monomer in the liquid dispersion medium, or when the polymerizable monomer is dispersed in the liquid dispersion medium. Refers to the dispersion performance to obtain particles of a size that can be used as Such dispersion performance can be realized by the configuration of the stirring device, the rotational speed of the stirring shaft, and the like.

  The step of dispersing may include a step of simultaneously polymerizing a polymerizable monomer, but a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is dispersed in a liquid dispersion medium. In order to apply the present invention to a suspension polymerization method or an emulsion polymerization method, it is preferable that the step is to make the particles fine and granulate, and the liquid dispersion medium is more preferably an aqueous dispersion medium. The aqueous dispersion medium is a liquid medium containing water as a main component and optionally containing auxiliary components such as a dispersion stabilizer and an emulsifier.

  The method for producing toner particles of the present invention includes the step of dispersing, and is not particularly limited as long as it is a method of producing toner particles by polymerizing the polymerizable monomer dispersed in this step. A step of preparing a polymerizable monomer composition, a step of preparing the liquid dispersion medium, a step of polymerizing the dispersed polymerizable monomer, and a step of taking out the particulate polymer obtained in the step of polymerizing Other processes such as these may be included.

Next, the present invention will be described in detail with reference to preferred embodiments of the present invention.
An example of a system that can carry out the toner particle manufacturing method of the present invention is shown in FIG. This is an example, and the present invention is not limited to this. As shown in FIG. 3, this system is a liquid to be dispersed and is prepared by a dissolving device 10 for preparing a polymerizable monomer composition containing a polymerizable monomer and a colorant, and a dissolving device 10. Dispersing device 1 for dispersing the polymerizable monomer composition in a liquid dispersion medium to granulate droplets of the polymerizable monomer composition, and the polymerizable monomer composition obtained by the dispersing device 1 A polymerization apparatus 11 for polymerizing the polymerizable monomer in the fine particles, and a post-treatment apparatus 12 for taking out the particulate polymer produced by the polymerization apparatus 11.

  Known devices are used as the dissolving device 10, the polymerization device 11, and the post-processing device 12. The dissolution apparatus 10 includes a dissolution container and a stirrer that stirs the inside of the dissolution container. The melting container is provided with a jacket for adjusting the temperature of the contents of the melting container. The polymerization apparatus 11 includes a polymerization container and a stirrer that stirs the inside of the polymerization container. The polymerization vessel is provided with a jacket for adjusting the temperature of the contents of the polymerization vessel. The post-processing device 12 is provided with a filtering means, a washing tank, and the like.

  As shown in FIG. 1, the dispersion apparatus 1 includes a dispersion container 1a, a stirring device 2 provided near the bottom of the dispersion container 1a, and a motor 13 provided outside the bottom of the dispersion container 1a. , A rotatable stirring shaft 3 for connecting the stirring device 2 and the motor 13, a shower ring device 8 provided at the upper part inside the dispersion vessel 1a, and an accommodation of the dispersion vessel 1a provided at the bottom of the dispersion vessel 1a And a discharge valve 9 for discharging the gas. The dispersion container 1a is provided with a jacket 7 for adjusting the temperature of the contents of the dispersion container 1a. The stirring device 2 is provided at a position shifted from the central axis of the dispersion vessel 1a so that the axis of the stirring shaft 3 and a straight line extending in the vertical direction form a predetermined angle (α).

  As shown in FIG. 2, the stirring device 2 includes a stirring blade 4 provided at the tip of the stirring shaft 3, and a screen 5 that forms a stirring chamber 6 that contains the stirring blade 4 and has a liquid passage hole 14. Have. The screen 5 is formed in a cup-like shape having a hole through which the stirring shaft 3 passes at the bottom and a liquid passage hole 14 on the peripheral wall, and forms a stirring chamber 6 having an open portion upward. Yes. The screen 5 is provided immovably with respect to the stirring shaft 3. The stirring blade 4 is formed in a shape having a straight edge that is separated from the peripheral wall of the screen 5 provided with the liquid passage hole 14 by a predetermined distance. The liquid passage holes 14 are elongated holes extending along the height direction of the peripheral wall of the screen 5, and a plurality of liquid passage holes 14 are provided with a predetermined interval.

  In addition, the screen 5 is not limited to the said form, For example, using the screen by which the surrounding wall or the whole was formed with the mesh is also mentioned as preferable embodiment of this invention.

  When the suspension polymerization toner method is used in the toner production method of the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and an additive to be added if necessary is used in the dissolution apparatus 10. Prepare while stirring and heating. At this time, if there are additives that are difficult to disperse uniformly in the dissolution vessel, such additives and other appropriate additives may be dispersed and dissolved in other steps in advance and added to the dissolution vessel. good.

  On the other hand, in the dispersion solution 1a, by stirring with the stirring device 2, a liquid dispersion medium substantially incompatible with the polymerizable monomer composition is prepared. Thereafter, the polymerizable monomer composition described above is put into a liquid dispersion medium.

  In the dispersing device 1, the liquid containing the polymerizable monomer composition and the liquid dispersion medium enters the stirring chamber 6 from the upper part of the stirring device 2 and is generated between the stirring blade 4 rotating at high speed and the screen 5. Agitated by strong shear, impact and turbulence. By this stirring, the polymerizable monomer in the liquid is ejected from the liquid passage hole 14 into the dispersion vessel 1a as micron-order particles. After stirring for a predetermined time until the desired particle size of the polymerizable monomer composition is obtained, a slurry composed of a liquid dispersion medium and a fine particle polymerizable monomer composition is transferred to the polymerization apparatus 11.

  In the stirring device 2 configured as described above, the shape of the stirring blade 4, the mesh diameter of the screen 5, and the gap between the stirring blade 4 and the screen 5 can be changed, and the viscosity of the liquid to be dispersed and the final desired coating can be changed. Depending on the particle size of the dispersion, etc., the stirring device 2 having a preferable form can be used as appropriate.

  Further, in the dispersion apparatus 1 having the above-described configuration, when the slurry is sent to the polymerization apparatus 11 or after the transfer, the showering is performed by the showering device 8 in order to remove the deposits and prevent the deposits from accumulating. Is preferable. For the showering, a liquid as a main component of the liquid dispersion medium, a liquid excellent in compatibility with the polymerizable monomer composition, or the like can be used. The liquid used for showering is appropriately selected depending on the composition of the polymerizable monomer composition, the timing of showering, and the like.

  In the polymerization apparatus 11, a polymerization initiator is added to the slurry as necessary, and the polymerizable monomer is polymerized by heating. After dispersion in the dispersion apparatus 1, the particle state (droplets) of the polymerizable monomer composition is maintained by the stabilizing action of the liquid dispersion medium, so that the polymerization apparatus 11 settles the particles of the polymerizable monomer composition. Stirring to such an extent that can be prevented may be performed by a stirring blade. The polymerization initiator may be added to the polymerizable monomer composition at any time before polymerization, and the addition time is not limited to just before the start of polymerization.

  The polymerization temperature is set to 40 ° C. or higher, generally 50 to 90 ° C. At this time, a plurality of polymerization temperatures may be set according to the polymerization time. The polymerization of the polymerizable monomer is preferably performed in the latter half. Furthermore, in order to remove unreacted polymerizable monomers and by-products, it is preferable to distill off a part of the liquid dispersion medium (aqueous dispersion medium) in the latter half of the polymerization reaction or after the completion of the polymerization reaction. . In particular, when saturated steam at 100 ° C. or more is charged into a polymerization vessel and distilled off, unreacted polymerizable monomers and by-products can be efficiently removed.

  Thereafter, the obtained slurry is transferred to the post-treatment device 12, and components such as a dispersion stabilizer in the liquid dispersion medium are removed as necessary. Toner particles are obtained by washing, filtering and drying the remaining solid particles.

  In the granulation (dispersion) step described above, in order to perform granulation at a certain constant temperature, a jacket 7 is usually provided in the dispersion vessel 1a, and warm water or steam is passed through the jacket 7, and cold water or the like is flowed as necessary. It is preferable to control the temperature in the dispersion vessel 1a.

  Further, according to the stirring device 2, the liquid flow in the dispersion container 1 a is sucked into the stirring device 2 from above the stirring device 2, and is ejected from the stirring device 2 to below the stirring device 2. In this case, the polymerizable monomer composition is sent into the stirring chamber 6 very efficiently, and fine particles of the polymerizable monomer composition having a sharper particle size distribution can be obtained.

  Moreover, in the stirring apparatus 2, since the stirring shaft 3 is not installed on the upper part of the stirring apparatus 2, the stirring flow is not disturbed by the stirring shaft 3 and the ideal flow pattern is obtained in the dispersion vessel 1a. The fine particles of the polymerizable monomer composition which are formed in the liquid phase and have a sharper particle size distribution are obtained.

  Conventionally, since the motor is installed on the top of the dispersion container or the lid on the top of the dispersion container, the stirring shaft of the dispersion apparatus extends from the top of the dispersion container to the vicinity of the bottom of the dispersion container in the vertically downward direction or the equivalent direction. It was a long stirring axis. This is a result of increasing the stirring efficiency by using the hydraulic pressure by installing the stirring blade at the bottom because the stirring efficiency deteriorates due to cavitation or splashing when the stirring blade is installed near the liquid surface. However, this long stirring shaft has a large area of the heat generating surface on the stirring shaft and has a large thermal influence on the polymerizable monomer composition. In order to prevent this, as described above, the stirring shaft is made into a jacket structure to suppress the thermal influence. However, the configuration of the stirring shaft becomes complicated, leading to an increase in equipment costs. Yes.

  On the other hand, in the dispersion apparatus 1 in the present embodiment, the stirring device 2 is provided at the bottom of the dispersion container 1a, and the motor 13 is provided outside the bottom of the dispersion container 1a. The length of 3 is much shorter than the conventional stirring shaft, and the minimum length of the stirring shaft is realized. As a result, it is possible to suppress the thermal influence on the polymerizable monomer composition due to the heat generated from the stirring shaft as much as possible.

In addition, a gas-liquid interface formed at the interface between the liquid phase part in the dispersion container and the other gas phase part exists in the container, but in the conventional dispersion apparatus, as described above, Since a long stirring shaft extending from the top to the vicinity of the bottom of the dispersion vessel is used, the conventional stirring shaft is provided to penetrate the gas-liquid interface. The above-mentioned growth of deposits requiring maintenance is often observed at the gas-liquid interface around the stirring axis. In order to prevent these problems, the stirring shaft has a jacket structure or a showering device is installed to suppress the growth of deposits, but this increases the equipment cost of the dispersing device.

  On the other hand, in the dispersion apparatus 1 in this embodiment, the stirring device 2 is provided at the bottom of the dispersion container 1a, and the motor 13 is provided outside the bottom of the dispersion container 1a. Since it protrudes into the dispersion container 1a from the bottom of 1a, there is no gas-liquid interface around the stirring shaft 3. As a result, the growth of the above-mentioned deposit does not occur at all, and a reduction in maintenance costs and a reduction in equipment costs can be realized.

  Control of the particle diameter of the droplet particles obtained by dispersion in the dispersion apparatus 1 is usually performed by the amount of the dispersion stabilizer used in the liquid dispersion medium and the rotational speed of the stirring blade 4. Particles obtained by controlling the peripheral speed of the stirring blade 4 to 10 to 50 m / sec at the tip of the stirring blade 4 (the end of the stirring blade 4 that becomes the maximum outer periphery during rotation) as a result of extensive studies. From the viewpoint of sharpening the particle size distribution. When the peripheral speed is less than 10 m / sec, it is difficult to reduce the particle size of the droplet particles, and when it exceeds 50 m / sec, a large number of very fine particles that are inappropriate for use as a toner are generated. And the particle size distribution may be wide. In addition, excessive high speed operation may cause damage to the stirring device 2 due to the influence of cavitation erosion. Furthermore, it is more preferable to control the peripheral speed at the tip of the stirring blade 4 to 20 to 40 m / sec.

  In addition, the value of d / D, which is the ratio of the diameter of the stirring blade (the diameter of the maximum outer circumference during rotation) d and the inner diameter D of the dispersion vessel, is very important in achieving uniform stirring in the dispersion vessel. Is a factor. That is, if d / D is too small, sufficient agitation cannot be obtained, and if d / D is too large, the collision force with the inner wall of the container increases and turbulence is generated, which is not preferable. Therefore, as a result of studies by the present inventors, it was found that d / D is preferably in the range of 0.1 to 0.3.

  In the stirring device used in the toner manufacturing method of the present invention, the angle α formed by the straight axis formed by the stirring shaft and the central axis of the stirring blade and a straight line extending in the vertical direction is 60 ° or less. preferable. If α is larger than 60 °, the liquid fluid discharged from the stirring device disturbs the free surface of the liquid phase portion in the dispersion container, and this is not preferable. This liquid splash not only pollutes the side surface of the dispersion container, but also entrains air in the contents of the dispersion container to deteriorate the stirring efficiency. When bubbles are mixed, even if the stirring blade gives energy to the liquid, the bubbles themselves contract to absorb this energy and atomize the polymerizable monomer or polymerizable monomer composition. This is because the ability to do this is reduced. This reduction in stirring efficiency adversely affects the particle size distribution of the toner particles obtained.

  In the present invention, it is preferable that the discharge valve for discharging the contents in the dispersion container is provided below the stirring blade. If a discharge valve is provided above the stirring blade, a liquid pool is generated in the dispersion container, which is not preferable.

  In the dispersing device used in the present invention, it is preferable that the rotating direction of the stirring blade is rotatable in both the forward and reverse directions. This is very effective at the time of cleaning in the stirring device because the discharge direction is different by making the direction reverse. That is, deposits and scales in the dead space in the stirring chamber can be easily removed by reverse rotation.

In the present invention, the stirrer installed in the dispersion vessel 1a only needs to be equipped with a stirrer having a high shear force only in the liquid phase part. For example, a preferred example is a bottom type CLEARMIX (manufactured by MTechnic Co., Ltd.). As mentioned.

  Moreover, as a stirrer installed in the dissolution apparatus 10 and the polymerization apparatus 11, an apparatus that can uniformly stir the entire container is preferable. As such a stirrer, for example, a paddle wing, three retreat wings, an anchor wing, more preferably a full zone wing (manufactured by Shinko Pantech Co., Ltd.), a max blend wing (manufactured by Sumitomo Heavy Industries, Ltd.), a sun meller wing (Mitsubishi Heavy Industries, Ltd.) And a stirrer having, as stirring blades, a Hi-F mixer blade (manufactured by Soken Chemical Co., Ltd.), a bend leaf blade (manufactured by Yako Sangyo Co., Ltd.), a resolver blade (manufactured by Mtechnic Co., Ltd.)

  Furthermore, as shown in FIG. 4, when producing toner particles having both a fixing property and anti-blocking property such that the toner particles have a core / shell structure and the shell portion is formed by polymerization, each toner particle It is necessary that the low softening point substance is present in the same proportion, but also in this respect, it is important to control the particle size distribution during granulation. In the production method of the present invention, since the particle size distribution of the droplet particles of the polymerizable monomer composition at the time of granulation can be sharpened, such a problem can be solved.

  Moreover, as a main component of a core part, a low softening point substance is preferable and the compound whose main body maximum peak value measured based on ASTM D3418-8 shows 40-90 degreeC is preferable. When the maximum peak is less than 40 ° C., the self-aggregation force of the low softening point substance becomes weak, and as a result, the high-temperature offset property during fixing of the toner image becomes weak, which is not preferable. On the other hand, when the maximum peak exceeds 90 ° C., the fixing temperature of the toner becomes high, which is not preferable. Furthermore, if the temperature of the maximum peak value is high, a low softening point substance may be precipitated mainly during granulation, which may hinder the suspension system.

  In the present invention, for example, DSC-7 manufactured by Perkin Elmer is used for measuring the temperature of the maximum peak value of the low melting point substance. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. As the sample, an aluminum pan is used, an empty pan is set as a control, and the sample is measured at a heating rate of 10 ° C./min.

  The low melting point material is preferably a release agent, and various waxes can be used as the release agent. Examples of the wax include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax.

  Examples of the wax include oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax; or block copolymers thereof; plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax; Animal waxes such as lanolin and whale wax; mineral waxes such as ozokerite, ceresin and petrolatum; waxes based on aliphatic esters such as montanic ester wax and castor wax; aliphatics such as deoxidized carnauba wax The wax etc. which have a functional group like the wax which deoxidized ester partially or entirely are mentioned.

Further, the wax includes saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a long-chain alkyl group; non-specific such as brassic acid, eleostearic acid, and valinal acid. Saturated fatty acids; stearyl alcohol, eicosyl alcohol, behenyl alcohol, cannavir alcohol, seryl alcohol, melyl alcohol, or saturated alcohols such as alkyl alcohols having a long chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amides; Aliphatic amides such as oleic acid amide and lauric acid amide; saturated aliphatic bis such as methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide and hexamethylene bis stearic acid amide Mid; unsaturated fatty acid amides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid Amido, aromatic bisamides such as N, N'-distearylisophthalic acid amide; aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as metal soap); behenine Examples include partially esterified products of fatty acids such as acid monoglycerides and polyhydric alcohols; waxes such as methyl ester compounds having hydroxyl groups obtained by hydrogenating vegetable oils and the like.

  Furthermore, examples of the wax include wax grafted with a vinyl monomer. Examples of the wax grafted with a vinyl monomer include a wax obtained by grafting an aliphatic hydrocarbon wax with a vinyl monomer such as styrene or acrylic acid.

  Preferred waxes include polyolefins obtained by radical polymerization of olefins under high pressure; polyolefins obtained by purifying low molecular weight by-products obtained during polymerization of high molecular weight polyolefins; polyolefins polymerized using a catalyst such as a Ziegler catalyst or a metallocene catalyst under low pressure; Polyolefins polymerized using radiation, electromagnetic waves or light; paraffin wax, microcrystalline wax, Fischer-Tropsch wax; synthetic hydrocarbon wax synthesized by the Gintor method, Hydrocol method, Age method, etc. Synthetic wax as a monomer; hydrocarbon wax having a functional group such as a hydroxyl group, carboxyl group or ester group; a mixture of a hydrocarbon wax and a hydrocarbon wax having a functional group; Styrene, maleic acid ester, acrylate, methacrylate, graft-modified wax with such vinyl monomers of maleic acid.

  In addition, the molecular weight distribution of these waxes is sharpened using a press sweating method, a solvent method, a recrystallization method, a vacuum distillation method, a supercritical gas extraction method or a melt liquid crystal deposition method, a low molecular weight solid fatty acid, a low A molecular weight solid alcohol, a low molecular weight solid compound, and other impurities are preferably used in the present invention.

  Further, it is preferable to add 5 to 30% by mass of the wax, which is one of the low softening point substances, into the toner particles. If the addition is less than 5% by mass, it is difficult to obtain good toner fixing properties and offset resistance, and if it exceeds 30% by mass, the toner particles are coalesced during granulation even in the production by the polymerization method. It is easy to occur and toner particles having a wide particle size distribution are easily generated.

  As a method for embedding the low softening point substance in the toner particles, the polarity of the material in the aqueous dispersion medium is set smaller than that of the main polymerizable monomer, and a smaller amount of polarity is set. The method of adding a big resin or a polymerizable monomer is mentioned. According to such a method, toner particles having a core / shell structure in which a low softening point substance is coated with a resin can be obtained.

  Control of the particle size distribution and average particle size of the toner particles can be achieved by a method of changing the kind and addition amount of a hardly water-soluble inorganic salt and a dispersion stabilizer that acts as a protective colloid, and a stirrer installed in a dispersion vessel. Control the peripheral speed of the stirring blade, the number of passes that are the number of passes through the liquid passage hole 14 of the screen 5, the stirring conditions such as the shape of the stirring blade, the shape of the dispersion vessel, or the solid content concentration in the aqueous dispersion medium. Thus, toner particles having a predetermined average particle diameter with a predetermined particle size distribution can be obtained.

In the present invention, a specific method for measuring the tomographic plane of the toner particles is to sufficiently disperse the toner particles in a room temperature curable epoxy resin and then to cure in an atmosphere at a temperature of 40 ° C. to obtain a cured product. The obtained cured product was dyed with ruthenium tetroxide and, if necessary, osmium tetroxide, and then a microtome with diamond teeth was used to cut out a flaky sample from the cured product. From the above, there is a method of observing the tomographic morphology of toner particles using a transmission electron microscope (TEM). In the present invention, it is preferable to use a ruthenium tetroxide dyeing method in order to provide a contrast between materials by utilizing a slight difference in crystallinity between the low softening point substance used and the resin constituting the outer shell. .

  Examples of the polymerizable monomer used in the present invention include styrene; o- (m-, p-) methylstyrene, styrenic monomers such as m- (p-) ethylstyrene; methyl (meth) acrylate, Ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, ( (Meth) acrylic acid ester monomers such as 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) acrylonitrile, acrylic An ene monomer such as acid amide is used. These polymerizable monomers are used alone or in combination.

  These are generally polymerizable so that the theoretical glass transition temperature (Tg) described in the publication Polymer Handbook 2nd edition III-P139-192 (John Wiley & Sons) is 40-80 ° C. It is used by appropriately mixing the monomer. When the theoretical glass transition temperature is less than 40 ° C., the storage stability of the toner and the durability of the toner are liable to be lowered. On the other hand, when it exceeds 80 ° C., the fixing temperature is increased, particularly in the case of a full color toner. The color mixing property of each color toner tends to be lowered, and the transparency of the OHP image tends to be lowered.

  As for the molecular weight of the shell (outer shell resin) of the toner particles having a core / shell structure, the number average molecular weight (Mn) of the outer shell resin is preferably 5,000 to 1,000,000, and the weight average molecular weight (Mw) The number average molecular weight (Mn) ratio (Mw / Mn) is preferably 2 to 100, more preferably 4 to 100. The molecular weight of the outer shell resin is measured by gel permeation chromatography (GPC).

  As a specific GPC measurement method, toner or toner particles are extracted in advance using a Soxhlet extractor with a toluene solvent for 20 hours, and then toluene is distilled off using a rotary evaporator. Further, the low softening point substance is dissolved. However, an organic solvent that cannot dissolve the outer shell resin (for example, chloroform) is added and thoroughly washed, and then a solution soluble in tetrahydrofuran (THF) is added to a solvent-resistant membrane filter having a pore diameter of 0.3 μm. The sample filtered in is measured using 150C manufactured by Waters. As a column in the measurement, molecular weight distribution can be measured by using a standard polystyrene resin calibration curve using A-801, 802, 803, 804, 805, 806 and 807 manufactured by Showa Denko. .

  In the present invention, when producing toner particles having a core / shell structure, it is particularly preferable to add a polar resin in addition to the outer shell resin in order to encapsulate the low softening point substance in the outer shell resin. . As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin are preferably used.

The polar resin is particularly preferably one containing no unsaturated group capable of reacting with the outer shell resin or the polymerizable monomer in the molecule. In the case of containing a polar resin having a reactive unsaturated group, a crosslinking reaction occurs between the polymerizable monomer forming the outer shell resin layer and the polar resin, and a high molecular weight component and / or a THF insoluble component is present. The resulting toner has a high molecular weight as a full color toner and is not preferable as a full color toner.

  In the present invention, an outermost resin layer may be further provided on the surface of the toner particles. In order to further improve the blocking resistance, the glass transition temperature of the outermost shell resin layer is preferably higher than the glass transition temperature of the outer shell resin layer and further crosslinked to such an extent that the fixing property is not impaired. . Further, the outermost shell resin layer may contain a polar resin or a charge control agent in order to improve chargeability.

The method for providing the outermost shell layer is not particularly limited, and examples thereof include the following methods.
(1) In the latter half of the polymerization reaction or after completion, if necessary, a polymerizable monomer in which a polar resin, a charge control agent, and a crosslinking agent are dissolved or dispersed is added to an aqueous dispersion medium in which toner particles are present. A method of carrying out polymerization by adsorbing to toner particles and adding a polymerization initiator.
(2) If necessary, emulsion-polymerized particles or soap-free polymerized particles formed of a polymerizable monomer containing a polar resin, a charge control agent, and a crosslinking agent are placed in an aqueous dispersion medium in which toner particles are present. A method of adding, agglomerating on the surface of the toner particles, and further fixing by heat if necessary. (3) If necessary, the emulsion-polymerized particles or soap-free polymerized particles formed of a polymerizable monomer containing a polar resin, a charge control agent, a crosslinking agent, etc. are mechanically applied to the toner particle surface in a dry manner. How to fix.

  As the colorant used in the present invention, various colorants such as a black colorant can be used. Carbon black and magnetic material are used as the black colorant.

  When a magnetic material is used as the black colorant, the following magnetic materials can be used. In this case, the magnetic material contained in the magnetic toner particles includes iron oxides such as magnetite, maghemite and ferrite, and iron oxides including other metal oxides; metals such as Fe, Co and Ni, or these metals. And alloys of Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, V, and mixtures thereof. Can be mentioned.

Specifically, as the magnetic material, triiron tetroxide (Fe ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc iron oxide (ZnFe ₂ O ₄ ), iron yttrium oxide (Y ₃ Fe) ₅ O ₁₂ ), iron cadmium oxide (CdFe ₂ O ₄ ), iron gadolinium oxide (Gd ₃ Fe ₅ O ₁₂ ), iron oxide copper (CuFe ₂ O ₄ ), iron oxide lead (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂ O ₄ ), iron niobium oxide (NdFe ₂ O ₃ ), barium oxide (BaFe ₁₂ O ₁₉ ), magnesium iron oxide (MgFe ₂ O ₄ ), iron lanthanum oxide (LaFeO ₃ ), iron powder (Fe) , Cobalt powder (Co), and nickel powder (Ni). You may use the magnetic body mentioned above individually or in combination of 2 or more types.

  The shapes of these magnetic materials include octahedrons, hexahedrons, spheres, needles, and scales, but those having less anisotropy such as octahedrons, hexahedrons, and spheres are preferable in terms of increasing the image density.

  Thus, when using a magnetic body as a black coloring agent, unlike other coloring agents, 40-150 mass parts is used with respect to 100 mass parts of polymerizable monomers or resin. The surface of the magnetic material is preferably subjected to a hydrophobic treatment.

When hydrophobizing the particle surface of the magnetic substance, the surface of the magnetic substance particle is hydrolyzed in a water-based medium while the coupling agent is hydrolyzed while dispersing the magnetic substance particles to a primary particle size. The surface is particularly preferable because it is uniform and is appropriately hydrophobized. This hydrophobization method in water or in an aqueous medium is less likely to cause coalescence between magnetic particles than the dry treatment method in the gas phase, and there is a charge repulsion effect between the magnetic particles due to the hydrophobization treatment. Thus, the magnetic particles are surface-treated in the state of primary particles.

  The method of treating the surface of magnetic particles while hydrolyzing the coupling agent in an aqueous medium does not require the use of a coupling agent that generates a gas, such as chlorosilanes and silazanes. In the gas phase, magnetic particles can be easily combined with each other, and a highly viscous coupling agent that has been difficult to be processed can be used, thereby increasing the hydrophobizing effect.

  When magnetic particles are used as the colorant, examples of the coupling agent that can be used in the surface treatment include a silane coupling agent and a titanium coupling agent. More preferably used are silane coupling agents, which are represented by the following general formula (1).

R _m SiY _n (1)
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group, or a methacryl group, and n represents an integer of 1 to 3. Show. ]

  Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxy. Propyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, Methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxy Orchids, n- butyl trimethoxysilane, isobutyl trimethoxysilane, trimethyl methoxysilane, hydroxypropyl Ritori silane, n- hexadecyl trimethoxysilane, n- octadecyl trimethoxysilane, and the like.

  Of these, to improve the dispersibility of the magnetic material, it is preferable to use a silane coupling agent having a double bond, such as phenyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethyl. Methoxysilane is more preferred. This is thought to be due to the better compatibility between the magnetic substance and the polymerizable monomer when treated with a coupling agent having a double bond, particularly in suspension polymerization. The dispersibility of the magnetic material is good.

  As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 168, 174, 176, 180, 181 and 191 are preferably used.

As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacdrine compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1
81: 1, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254.

  As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 are preferably used.

  In the case of a color toner, the colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner particles. The addition amount of the nonmagnetic colorant is 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer or the resin in the polymerized particles.

  In the present invention, a charge control agent can be added to the polymerizable monomer composition. A well-known thing can be utilized as a charge control agent used for this invention. In the case of a color toner, a charge control agent that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is particularly preferable. Furthermore, a charge control agent having no polymerization inhibition and no solubilized product in an aqueous medium is particularly preferred. Negative charge control agents include salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid metal compounds; polymer compounds having sulfonic acid or / and carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, calixes Arene. Examples of the positive charge control agent include quaternary ammonium salts, polymer compounds having the quaternary ammonium salt in the side chain, guanidine compounds, and imidazole compounds.

  The charge control agent is preferably used in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin in the particles after polymerization. However, in the present invention, it is not essential to add a charge control agent. In the case of the two-component development method, friction charging between the carrier and the toner is used. In the non-magnetic one-component development method, a blade for blade coating is used. In some cases, it is possible to control the charging of the toner by actively using frictional charging between the member or the sleeve member and the toner. In such a case, the toner particles do not necessarily contain a charge control agent. There is no need.

  Examples of the polymerization initiator used in the present invention include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane- 1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or diazo polymerization initiators such as azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxy Examples thereof include peroxide-based polymerization initiators such as carbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, t-butylperoxyl diethylhexanate, and t-butylperoxypivalate.

  Although the addition amount of a polymerization initiator changes with the target degree of polymerization, generally it is 0.5-20 mass% with respect to a polymerizable monomer, Preferably it is 0.5-5 mass%. . The kind of the polymerization initiator is slightly different depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.

  Moreover, in this invention, in order to control the polymerization degree of resin formed by superposition | polymerization of a polymerizable monomer, you may further add a well-known crosslinking agent, a chain transfer agent, and a polymerization inhibitor.

Examples of the cross-linking agent include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; diacrylate compounds linked by an alkyl chain such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, and 1,4- Examples include butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylates of the above compounds with methacrylates; alkyl chains containing ether bonds Examples of the diacrylate compounds connected with each other include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, and polyethylene glycol # 400 diacrylate. Acrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds are replaced by methacrylate; diacrylate compounds linked by a chain containing an aromatic group and an ether bond, Oxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate and methacrylates of the above compounds The polyester type diacrylates include trade name MANDA (Nippon Kayaku).

  Polyfunctional cross-linking agents include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds replaced with methacrylate; triallylcia Examples include nurate and triallyl trimellitate.

  When a suspension polymerization method is used as a method for producing toner particles, as a dispersion stabilizer to be used, tricalcium phosphate, hydroxyapatite, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, water Examples thereof include inorganic dispersion stabilizers such as calcium oxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. Examples of the organic dispersion stabilizer include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, and starch.

  In the method for producing toner particles of the present invention, an inorganic dispersion stabilizer is preferable in order to prevent aggregation of toner particles in the step of removing organic volatile components. These dispersion stabilizers are preferably used in an amount of 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Water or an aqueous dispersion medium is preferably used in an amount of 300 to 3000 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  A commercially available dispersion stabilizer may be used as it is, but in order to obtain a dispersion stabilizer having a fine uniform particle size, the inorganic dispersion stabilizer is produced under high-speed stirring in water or an aqueous medium. It is also a preferable method. For example, in the case of tricalcium phosphate or hydroxyapatite, a dispersion stabilizer preferable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring. Moreover, you may use together 0.001-0.1 mass part surfactant for refinement | miniaturization of these dispersion stabilizers.

  Examples of the surfactant include commercially available nonionic, anionic, and cationic surfactants. Examples include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and calcium oleate.

The external additive of the toner particles preferably has a particle size of 1/10 or less of the weight average particle size of the toner particles from the viewpoint of durability when externally added to the toner particles. The particle diameter of the external additive means the number average particle diameter obtained by observing the surface of the toner particles with an electron microscope. Examples of external additives include metal oxides (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitrides (silicon nitride, etc.), carbides (carbonization) Silicon), metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica and the like.

  The external additive is used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the toner particles. The external additives may be used alone or in combination. Those subjected to a hydrophobizing treatment with a silane coupling agent and / or silicone oil are more preferable.

  The particle size distribution of the toner particles can be measured by various methods. In the present invention, it is preferable to use a Coulter counter.

  Coulter counter multisizer type I, type II or type IIe (manufactured by Coulter) is used as the measuring device, and an interface (manufactured by Nikkiki) that outputs the number average distribution and volume average distribution to such a measuring device and general Connect a personal computer. Also, a 1% NaCl aqueous solution is prepared as an electrolytic solution using special grade or first grade sodium chloride.

  As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is subjected to a dispersion process for about 1 to 3 minutes with an ultrasonic disperser, and with the Coulter Counter Multisizer II type, a 100 μm aperture is used as an aperture, and 2 to 40 μm particles based on the number The particle size distribution is measured and various values are obtained therefrom.

  The coefficient of variation in the number distribution is calculated from the following equation (2).

Coefficient of variation (%) = [S / D1] × 100 (2)
[In the formula, S represents a standard deviation in the number distribution of toner particles, and D1 represents a number average particle diameter (μm) of toner particles. ]

  Hereinafter, the present invention will be described specifically by way of examples.

[Example 1]
After introducing 5 parts by mass of Na ₃ PO ₄ into 500 parts by mass of ion-exchanged water contained in the dispersion container 1a shown in FIG. 1 and heating to 60 ° C., the dispersion container 1a shown in FIG. Then, a bottom type Claremix high speed stirrer (manufactured by M Technique Co., Ltd., peripheral speed 22 m / s, α = 30 °) composed of the stirring device 2, the stirring shaft 3 and the motor 13 was installed and stirred. To this, an aqueous solution in which ₂ parts by mass of CaCl ₂ was dissolved in 15 parts by mass of ion-exchanged water was quickly added to obtain an aqueous dispersion medium containing Ca ₃ (PO ₄ ) ₂ .

・ Polymerizable monomer Styrene 85 parts by mass
20 parts by mass of n-butyl acrylate / colorant C.I. I. Pigment Blue 15: 3 7.5 parts by mass / charge control agent E-88 (manufactured by Orient Chemical Industries) 1 part by mass / polar resin saturated polyester 5 parts by mass
(Acid value 10 mgKOH / g, peak molecular weight: 7,500)
・ Release agent Ester wax
(Maximum endothermic peak temperature in DSC 72 ° C.) 15 parts by mass On the other hand, the material was heated to 60 ° C. in the dissolving apparatus 10 and stirred to uniformly dissolve or disperse each material in the polymerizable monomer. To this was added 3 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator to prepare a polymerizable monomer composition.

The polymerizable monomer composition in the dissolution apparatus 10 is introduced into the aqueous dispersion medium in the dispersion container 1a, and then for 15 minutes in the stirring apparatus 2 in the dispersion container 1a at 60 ° C. in an N ₂ atmosphere ( The tip peripheral speed of the stirring blade 4 was 22 m / s), and particles of the polymerizable monomer composition were generated in the aqueous dispersion medium. As the flow pattern in the dispersion vessel 1a at this time, an ideal flow pattern flowing from the upper side to the lower side of the stirring device 2 was observed, and the polymerizable monomer composition was smoothly dispersed in the aqueous dispersion medium.

  After the dispersion, the stirring device 2 in the dispersion vessel 1a is stopped, and the contents in the dispersion vessel 1a are introduced into the polymerization device 11 equipped with a full zone stirring blade (manufactured by Shinko Pantech Co., Ltd.) via the discharge valve 9. did. At the same time, the shower ring device 8 installed in the dispersion vessel 1a was operated to clean the inside of the dispersion vessel 1a.

In the polymerization apparatus 11, the polymerizable monomer was reacted for 5 hours while stirring the stirring blade at the maximum peripheral speed of stirring: 3 m / s in a N ₂ atmosphere at a temperature of 60 ° C. Thereafter, the temperature was raised to 80 ° C., and the polymerizable monomer was further reacted for 5 hours. After completion of the polymerization reaction, the liquid in the polymerization container was sent to the post-processing device 12 to obtain toner particles.

  The particle size distribution and number variation coefficient of the obtained toner particles were measured. The results are shown in Table 1. When the tomographic plane of the toner particles was observed, a core / shell structure as shown in FIG. 4 was confirmed.

  Although these operations were repeated 40 times and continuous operation was performed, no deposits on the stirring shaft 3 in the dispersion vessel 1a were observed, and stable toner particles could be produced throughout. The particle size distribution of the toner particles obtained during these continuous operations was almost the same as the particle size distribution of the toner particles obtained in the first batch, and the toner quality was stable. Furthermore, although the stirring apparatus 2 was also inspected, no scratches or the like were observed.

[Example 2]
Except that a bottom type clear mix of α = 45 ° was used, the same operation as in Example 1 was performed to obtain toner particles. The particle size distribution and number variation coefficient of the obtained toner particles were measured. The results are shown in Table 1. When the tomographic plane of the toner particles was observed, a core / shell structure as shown in FIG. 4 was confirmed.

  Although these operations were repeated 40 times and continuous operation was performed, no deposits on the stirring shaft 3 in the dispersion vessel 1a were observed, and stable toner particles could be produced throughout. The particle size distribution of the toner particles obtained during these continuous operations was almost the same as the particle size distribution of the toner particles obtained in the first batch, and the toner quality was stable.

[Example 3]
Except that the peripheral speed of the stirring blade 4 was set to 35 m / s, the same operation as in Example 1 was performed to obtain toner particles. The particle size distribution and number variation coefficient of the obtained toner particles were measured. The results are shown in Table 1. When the tomographic plane of the toner particles was observed, a core / shell structure as shown in FIG. 4 was confirmed.

  Although these operations were repeated 40 times and continuous operation was performed, no deposits on the stirring shaft 3 in the dispersion vessel 1a were observed, and stable toner particles could be produced throughout. The particle size distribution of the toner particles obtained during these continuous operations was almost the same as the particle size distribution of the toner particles obtained in the first batch, and the toner quality was stable.

[Example 4]
Except that a bottom type clear mix of α = 75 ° was used, the same operation as in Example 1 was performed to obtain toner particles. Liquid disturbance was observed on the free surface during granulation. Specifically, it was observed that many bubbles were entrained in the liquid. These operations were repeated 40 times and a continuous operation was performed, but no deposits on the stirring shaft 3 in the dispersion vessel 1a were observed. The particle size distribution and number variation coefficient of the obtained toner particles were measured. The results are shown in Table 1.

[Example 5]
Except for setting the peripheral speed of the stirring blade 4 to 8 m / s, the same operation as in Example 1 was performed to obtain toner particles. These operations were repeated 40 times and a continuous operation was performed, but no deposits on the stirring shaft 3 in the dispersion vessel 1a were observed. The particle size distribution and number variation coefficient of the obtained toner particles were measured. The results are shown in Table 1.

[Example 6]
Toner particles were obtained in the same manner as in Example 1 except that the peripheral speed of the stirring blade 4 was changed to 60 m / s. The particle size distribution and number variation coefficient of the obtained toner particles were measured. The results are shown in Table 1. When these operations were repeated 30 times, the stirrer 2 was inspected, and countless scratches were observed in the stirrer 2. It is presumed to be a scratch caused by cavitation erosion caused by excessive high-speed driving. However, no deposits on the stirring shaft 3 in the dispersion container 1a were observed.

[Reference Example 1]
Toner particles were obtained in the same manner as in Example 1 except that the top type CLEARMIX shown in FIG. In this dispersing device, a motor 23 is provided above the dispersing vessel 1a, a stirring device 22 is provided near the bottom of the dispersing vessel 1a and immediately above the discharge valve 9, and a stirring shaft 33 is a liquid level in the dispersing vessel 1a. 1 is connected to the motor 23 and the stirrer 22, and the screen 25 is provided in a direction in which the cross-sectional area gradually decreases toward the tip of the stirrer shaft 33, similar to the disperser 1 shown in FIG. It is configured.

  The particle size distribution and number variation coefficient of the toner particles obtained in this reference example were measured. The results are shown in Table 1. When the tomographic plane of the toner particles was observed, a core / shell structure as shown in FIG. 4 was confirmed.

  Although these operations were repeated for continuous operation, the particle size distribution was adversely affected from around 30 times, and the particle size distribution was clearly broadened at the 40th time. This is presumed to be an adverse effect on the particle size distribution due to the thermal influence on the polymerizable monomer due to the heat generation of the stirring shaft 33 and the contamination of the deposits on the stirring shaft 33.

[Comparative Example 1]
Toner particles were obtained in the same manner as in Example 1, except that a TK-homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) shown in FIG. In this dispersing device, a motor 23 is provided above the dispersing vessel 1a, a stirring device 22 is provided near the bottom of the dispersing vessel 1a and immediately above the discharge valve 9, and a stirring shaft 33 is a liquid level in the dispersing vessel 1a. And a baffle plate 39 that blocks the flow of liquid in the direction along the axial direction of the stirring shaft 33 around the stirring shaft 33 between the dispersion vessel 1a and the stirring device 22. The configuration is the same as that of the dispersion apparatus 1 shown in FIG.

  In the liquid flow pattern in the dispersion container 1a, a flow pattern from the bottom to the top was observed, and apparently the free surface disorder of the liquid was observed. The particle size distribution and number variation coefficient of the obtained toner particles were measured. The results are shown in Table 1. In this comparative example, since satisfactory toner quality was not obtained, the operation was completed in one batch.

It is a figure which shows the structure of an example of the dispersion apparatus used for this invention. It is a figure which shows the cross section of the stirring apparatus and its principal part of the dispersion apparatus shown by FIG. It is a figure which shows an example of the system used for this invention. It is a figure which shows the cross section of an example of the toner particle manufactured by this invention. It is a figure which shows the structure of an example of a top type high-speed stirrer. It is a figure which shows the structure of the other example of a top type high speed stirrer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dispersing apparatus 1a Dispersing container 2, 22 Stirring apparatus 3, 33 Stirring shaft 4 Stirring blade 5, 25 Screen 6 Stirring chamber 7 Jacket 8 Showering apparatus 9 Drain valve 10 Dissolving apparatus 11 Polymerizing apparatus 12 Post-processing apparatus 13, 23 Motor 14 Flow hole 39 baffle plate

Claims (11)

A stirrer having a high shear force in which at least a polymerizable monomer is provided in a dispersion vessel connected to a rotating stirring shaft in a liquid dispersion medium substantially incompatible with the polymerizable monomer. In the method for producing toner particles, including the step of dispersing using the method, and polymerizing the polymerizable monomer dispersed in this step to produce toner particles,
In the dispersing step, at least the liquid dispersion medium and the polymerizable monomer are contained in the dispersion container in a liquid phase part formed between the liquid phase part and the gas phase part formed in the dispersion container. A method for producing toner particles, wherein the stirring shaft provided in a position including the stirring shaft inside and the stirring device is used.   The method for producing toner particles according to claim 1, wherein the liquid dispersion medium is an aqueous dispersion medium.   The step of dispersing is a step of dispersing and granulating a polymerizable monomer composition containing at least the polymerizable monomer and a colorant in the liquid dispersion medium. The method for producing toner particles according to claim 1.   4. The toner particle manufacturing method according to claim 1, wherein the stirring device is provided at a bottom portion of the dispersion container or in the vicinity thereof. 5.   5. The liquid phase part is formed in the liquid phase portion in the dispersion step so as to be sucked into the stirring device from above the stirring device and jetted from the stirring device to below the stirring device. The method for producing toner particles according to any one of the above.   The stirring device has a stirring blade that rotates with the rotation of the stirring shaft, and a screen that forms a stirring chamber containing the stirring blade, and the screen is opened toward the dispersion vessel. 6. The method for producing toner particles according to claim 1, wherein the stirring chamber is formed and has a liquid passage hole that opens in a wall surface of the stirring chamber.   The method for producing toner particles according to claim 6, wherein a peripheral speed of the stirring blade is 10 m / s to 50 m / s.   The said stirring shaft is connected to the lower part of the said stirring blade, The angle (alpha) which the axis line of the said stirring shaft and the straight line extended in a perpendicular direction make is 60 degrees or less, The Claim 6 or 7 characterized by the above-mentioned. A method for producing toner particles.   The said dispersion | distribution container has a discharge valve which discharges | emits at least the said polymerizable monomer and the said liquid dispersion medium, The said discharge valve is comprised below the said stirring blade. The method for producing toner particles according to any one of claims 1 to 8.   The method for producing toner particles according to claim 1, wherein toner particles having a core / shell structure are produced. The method for producing toner particles according to claim 10, wherein a main component of the core portion of the core / shell structure is a low softening point material having a melting point of 40 to 90 ° C.

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