JPWO2009069593A1 - Toner production method - Google Patents

Abstract

In the drying process, high-efficiency drying can be achieved without causing aggregation and / or fusion of the colored resin particles and fusion of the colored resin particles into the dryer. The present invention provides a toner manufacturing method that is excellent in printing performance and printing performance. Forming colored resin particles by a wet method to obtain an aqueous dispersion of colored resin particles, and washing the colored resin particles in the aqueous dispersion of colored resin particles with washing water to obtain an aqueous dispersion of colored resin particles In the toner manufacturing method including a washing step and a drying step of obtaining the colored resin particles by drying the colored resin particle aqueous dispersion, the colored resin particle aqueous dispersion adjusted to a predetermined solid content concentration in the washing step The colored resin particles are washed until the electrical conductivity of the filtrate obtained by filtering is reduced to 1000 μS / cm or less to prepare an aqueous dispersion of colored resin particles. In the drying step, the prepared colored resin particles This is a method for producing a toner in which an aqueous dispersion is supplied to a pulse shock wave dryer for drying, and the water content of the colored resin particles after drying is 0.5% by weight or less.

Description

  The present invention relates to a method for producing toner used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. More specifically, the present invention relates to a method for producing a toner that can be efficiently dried, has low fuel consumption for drying, and is excellent in productivity.

  Conventionally, in the drying process of the toner production method, it is necessary to sufficiently reduce the moisture content of the drying object in advance from the viewpoint of the fuel efficiency of the dryer, etc. before applying the drying object to the drying process. There was a dehydration process as a pre-process of the drying process.

In general, examples of the dryer used in the drying process of the toner production method include a dryer using a drying method such as a vacuum drying method, an airflow drying method, a spray drying method, and a fluidized bed drying method.
In the drying process, it should be noted that the temperature of the dryer is set in consideration of the glass transition temperature (Tg) of the resin occupying 90% or more of the constituent components of the toner.

  If the set temperature of the dryer used in the drying process is too high, the objects to be dried (colored resin particles) are aggregated and / or fused, and the objects to be dried (colored resin particles) are melted into the dryer. When the set temperature of the dryer is too low, moisture is sufficiently separated from the object to be dried (colored resin particles). There is a problem that the toner cannot be evaporated and a toner having high desired performance cannot be obtained.

  In Patent Document 1, the toner particles produced in the aqueous dispersion medium are washed and dehydrated, and in the step of drying the obtained wet toner particles, the drying means is a method of drying using an air flow, A method for producing toner particles is disclosed, wherein drying is performed so as to satisfy a specific particle size distribution.

However, in the production method of Patent Document 1, it is necessary to provide a dehydration step in which the moisture content of the object to be dried (colored resin particles) is reduced to about 40% or less before the drying step.
Further, since the Tg of the toner manufactured in Patent Document 1 is 40 to 75 ° C., since the set temperature of the dryer is 90 ° C., there are problems such as fusion of colored resin particles in the dryer. Presumed to have been caused.

  In Patent Document 2, in producing polymer fine particles from an aqueous polymer dispersion or aqueous solution, the production of polymer fine particles is characterized in that solid aqueous liquid dispersion or aqueous solution is brought into contact with a pulse shock wave for solid-liquid separation. A method is disclosed.

In the drying process of the manufacturing method of Patent Document 2, a liquid (water) can be separated and evaporated instantaneously (in a short time) at a low temperature from an object to be dried (aqueous dispersion or aqueous solution of a polymer). It is not necessary to provide a dehydration step because the drying method using a shock wave can be dried while the moisture content of the object to be dried is high.
Further, in the production method of Patent Document 2, since desired drying can be performed even at a low temperature, it is considered that problems such as particle fusion in the dryer do not occur. The high level that can be applied to the project has not been studied.

JP 2004-258589 A JP 2000-80170 A

  The object of the present invention is to enable highly efficient drying without causing aggregation and / or fusion of the colored resin particles and fusion of the colored resin particles into the dryer in the drying step. An object of the present invention is to provide a toner manufacturing method that has low fuel consumption, excellent productivity, and excellent printing performance.

  The present inventors have intensively studied to achieve the above object, and in the washing step, after washing the electric conductivity of the colored resin particle aqueous dispersion to a specific amount or less, in the drying step Then, the colored resin particle aqueous dispersion having a high degree of washing is supplied to a pulse shock wave dryer and dried, thereby agglomerating and / or fusing the colored resin particles and melting the colored resin particles into the dryer. It has been found that colored resin particles having a low moisture content of a specific amount or less can be obtained even when fuel consumption for drying can be reduced without causing wear, and even if fuel efficiency for drying is low. The invention has been completed.

That is, the toner production method of the present invention includes a step of forming colored resin particles by a wet method to obtain a colored resin particle aqueous dispersion, and the colored resin particles in the colored resin particle aqueous dispersion are washed with washing water. In the toner production method comprising a washing step of obtaining a colored resin particle aqueous dispersion and a drying step of drying the colored resin particle aqueous dispersion to obtain colored resin particles,
In the washing step, the colored resin particles are washed until the electric conductivity of the filtrate obtained by filtering the aqueous dispersion of colored resin particles adjusted to a predetermined solid content concentration is 1000 μS / cm or less. Prepare an aqueous dispersion,
In the drying step, the prepared colored resin particle aqueous dispersion is supplied to a pulse shock wave dryer for drying, and a toner having a water content of the colored resin particles after drying of 0.5% by weight or less is produced. Is the method.

  According to the toner production method of the present invention as described above, high efficiency can be achieved without causing aggregation and / or fusion of the colored resin particles and fusion of the colored resin particles into the dryer in the drying step. Provided is a toner manufacturing method that can be dried, has low fuel consumption for drying, is excellent in productivity, and is excellent in printing performance.

The method for producing a toner of the present invention includes a step of forming colored resin particles by a wet method to obtain a colored resin particle aqueous dispersion, and the colored resin particles in the colored resin particle aqueous dispersion are washed with washing water. In a method for producing a toner, including a washing step of obtaining an aqueous dispersion of colored resin particles and a drying step of obtaining the colored resin particles by drying the aqueous dispersion of colored resin particles,
In the washing step, the colored resin particles are washed until the electric conductivity of the filtrate obtained by filtering the aqueous dispersion of colored resin particles adjusted to a predetermined solid content concentration is 1000 μS / cm or less. Prepare an aqueous dispersion,
In the drying step, the prepared colored resin particle aqueous dispersion is supplied to a pulse shock wave dryer for drying, and the water content of the dried colored resin particles is 0.5% by weight or less.

Examples of the wet method include a polymerization method such as a suspension polymerization method, an emulsion aggregation polymerization method, and a dispersion polymerization method, and a dissolution suspension method. In the toner production method provided by the present invention, a polymerization method is used. It is preferable to employ a suspension polymerization method among the polymerization methods.
Hereinafter, a method for producing a toner by a suspension polymerization method will be described as a representative example.

(1) Step of obtaining colored resin particle aqueous dispersion This step includes (1-1) a polymerizable monomer composition preparation step, (1-2) a droplet formation step, and (1-3) a polymerization step. The desired colored resin particle aqueous dispersion can be obtained through each of the steps.

(1-1) Preparation Step of Polymerizable Monomer Composition First, a polymerizable monomer, a colorant, and, if necessary, other additives such as a charge control agent are mixed and dissolved to obtain a polymerizable monomer. The preparation of the monomer composition is performed. The mixing at the time of preparing the polymerizable monomer composition is performed using, for example, a media type dispersing machine.

The polymerizable monomer means a monomer having a polymerizable functional group. A monovinyl monomer is preferably used as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyl toluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic acid 2 Acrylic esters such as ethylhexyl and dimethylaminoethyl acrylate; methacrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate; acrylamide And amide compounds such as methacrylamide; olefins such as ethylene, propylene, and butylene; and the like. These monovinyl monomers can be used alone or in combination of two or more.
Of the monovinyl monomers, styrene, styrene derivatives, acrylic acid esters, and methacrylic acid esters are preferably used.

In order to improve the storage stability (blocking resistance) of the toner as a part of the polymerizable monomer, it is preferable to use any crosslinkable polymerizable monomer together with the monovinyl monomer. A crosslinkable polymerizable monomer refers to a monomer having two or more polymerizable functional groups. Examples of the crosslinkable polymerizable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N , N-divinylaniline, and divinyl compounds such as divinyl ether; compounds having three or more vinyl groups such as trimethylolpropane trimethacrylate and dimethylolpropane tetraacrylate; These crosslinkable polymerizable monomers may be used alone or in combination of two or more.
In the present invention, it is desirable to use the crosslinkable polymerizable monomer in a proportion of usually 0.1 to 5 parts by weight, preferably 0.3 to 2 parts by weight, with respect to 100 parts by weight of the monovinyl monomer. .

Further, as a part of the polymerizable monomer, it is preferable to use an arbitrary macromonomer together with the monovinyl monomer in order to improve the balance between the storage stability of the toner and the low-temperature fixability. The macromonomer is a reactive oligomer or polymer having a polymerizable carbon-carbon unsaturated bond at the end of the molecular chain and having a number average molecular weight (Mn) of usually 1,000 to 30,000. . As the macromonomer, it is preferable to use an oligomer or polymer having a Tg higher than the glass transition temperature (Tg) of a polymer (binder resin) obtained by polymerizing a polymerizable monomer.
In the present invention, the proportion of the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, and more preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the monovinyl monomer. It is desirable to use in.

  As a colorant, when manufacturing color toners (usually four types of toners of black toner, cyan toner, yellow toner, and magenta toner) are used, a black colorant, a cyan colorant, a yellow colorant, and a magenta colorant are used. Each agent can be used.

  As the black colorant, carbon black, titanium black, and pigments such as magnetic powders such as iron oxide zinc and iron oxide nickel can be used.

  As the cyan colorant, for example, a compound such as a copper phthalocyanine pigment, a derivative thereof, and an anthraquinone pigment is used. Specifically, C.I. I. Pigment Blue 2, 3, 6, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17: 1, 60, and the like.

  As the yellow colorant, for example, azo pigments such as monoazo pigments and disazo pigments, and compounds such as condensed polycyclic pigments are used. Specifically, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, 186, and the like.

  Examples of the magenta colorant include compounds such as monoazo pigments, azo pigments such as disazo pigments, and condensed polycyclic pigments. Specifically, C.I. I. Pigment Red 31, 48, 57: 1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170 , 184, 185, 187, 202, 206, 207, 209, 251 and C.I. I. Pigment Violet 19 and the like.

  In the present invention, each colorant may be used singly or in combination of two or more, and is preferably used in a ratio of 1 to 10 parts by weight with respect to 100 parts by weight of the monovinyl monomer.

As another additive, a release agent is preferably used in order to improve the releasability of the toner from the fixing roll.
The release agent is not particularly limited as long as it is generally used as a release agent for toner. For example, polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; candelilla, carnauba Natural waxes such as wax, rice, wax and jojoba; petroleum waxes such as paraffin, microcrystalline and petrolatum; mineral waxes such as montan, ceresin and ozokerite; synthetic waxes such as Fischer-Tropsch wax; pentaerythritol tetramyristate; Pentaerythritol esters such as pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, and pentaerythritol tetralaurate, and dipentaerythritol hexami State, dipentaerythritol hexa palmitate, and polyhydric alcohol ester compounds such as dipentaerythritol esters such as dipentaerythritol hexa laurate; and the like. These release agents may be used alone or in combination of two or more.
In this invention, it is desirable to use a mold release agent in the ratio of 0.1-30 weight part normally with respect to 100 weight part of monovinyl monomers, Preferably it is 1-20 weight part.

As other additives, various charge control agents having positive chargeability or negative chargeability can be used in order to improve the chargeability of the toner.
The charge control agent is not particularly limited as long as it is generally used as a charge control agent for toner, but in the present invention, among the charge control agents, the compatibility with the polymerizable monomer is high. Therefore, it is preferable to use a charge control resin because stable chargeability (charge stability) can be imparted to the toner particles.
As the charge control resin, for example, various commercially available products can be used. As the positively chargeable charge control resin, FCA-161P (trade name, styrene / acrylic resin), FCA-207P manufactured by Fujikura Kasei Co., Ltd. (: Trade name, styrene / acrylic resin), FCA-201-PS (: trade name, styrene / acrylic resin), and the like. As the negatively chargeable charge control resin, manufactured by Fujikura Kasei Co., Ltd., FCA- 626N (: trade name, styrene / acrylic resin), FCA-748N (: trade name, styrene / acrylic resin), FCA-1001N (: trade name, styrene / acrylic resin), and the like.
In the present invention, it is desirable to use the charge control agent in a proportion of usually 0.01 to 10 parts by weight, preferably 0.5 to 8 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

It is preferable to use a molecular weight modifier as another additive.
The molecular weight modifier is not particularly limited as long as it is generally used as a molecular weight modifier for toner. For example, t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2, Mercaptans such as 4,6,6-pentamethylheptane-4-thiol; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N, N′-dimethyl-N, N′-diphenylthiuram disulfide, N, And thiuram disulfides such as N′-dioctadecyl-N and N′-diisopropylthiuram disulfide; These molecular weight modifiers may be used alone or in combination of two or more.
In the present invention, it is desirable to use the molecular weight modifier in a proportion of usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

(1-2) Droplet formation step The polymerizable monomer composition obtained through the preparation step of the above (1-1) polymerizable monomer composition is placed in an aqueous dispersion medium containing a dispersion stabilizer. After the dispersion and the polymerization initiator are added, droplets of the polymerizable monomer composition are formed. The method of forming droplets is not particularly limited. For example, an in-line type emulsifier / disperser (trade name: Milder, manufactured by Taiheiyo Kiko Co., Ltd.), a high-speed emulsifier / disperser (product name: TK Homomixer MARK) It can be carried out using a device capable of strong stirring such as type II).

In forming droplets, a dispersion stabilizer is used in an aqueous dispersion medium in order to control the particle diameter of the colored resin particles and improve the circularity.
The aqueous dispersion medium may be water alone, but can also be used in combination with a solvent that is soluble in water, such as lower alcohol and lower ketone.

  Examples of the dispersion stabilizer include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metals such as aluminum oxide and titanium oxide. Oxides and metal compounds such as metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; water-soluble polymer compounds such as polyvinyl alcohol, methyl cellulose, and gelatin; anionic surfactants , Organic polymer compounds such as nonionic surfactants and amphoteric surfactants; Among these, metal hydroxides are preferable, and magnesium hydroxide used in a pH range of usually 7.5 to 11 is particularly preferable.

Among the above dispersion stabilizers, a dispersion stabilizer containing a metal hydroxide colloid dissolved in an acid solution is preferably used. The dispersion stabilizers can be used alone or in combination of two or more.
The amount of the dispersion stabilizer added is preferably 0.1 to 20 parts by weight and more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

  Examples of the polymerization initiator include inorganic persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-methyl-N— (2-hydroxyethyl) propionamide, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2,4-dimethylvaleronitrile), and 2,2′-azobisisobuty Azo compounds such as nitrile; di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy Pivalate, diisopropyl peroxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyl Organic peroxides rate, etc.;., Etc. Among these, organic peroxides are suitably used.

As described above, the polymerization initiator may be added at the stage before the droplet formation after the polymerizable monomer composition is dispersed in the aqueous dispersion medium containing the dispersion stabilizer. It may be added directly to the polymerizable monomer composition.
The addition amount of the polymerization initiator is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 15 parts by weight with respect to 100 parts by weight of the monovinyl monomer, and 1.0 to 10 parts by weight. More preferably, it is part by weight.

(1-3) Polymerization Step The suspension (aqueous dispersion containing droplets of the polymerizable monomer composition) obtained through the above (1-2) droplet formation step is treated in the presence of a polymerization initiator. In this way, an aqueous dispersion of colored resin particles can be obtained by suspension polymerization.
In the polymerization step, in order to carry out the polymerization in a state where the droplets of the polymerizable monomer composition are stably dispersed, the polymerization reaction is carried out while performing a dispersion treatment by stirring following the above (1-2) droplet formation step. It is preferable to proceed.

  In the polymerization step, the polymerization temperature is preferably 50 ° C. or higher, and more preferably 60 to 98 ° C. Further, the polymerization time is preferably 1 to 20 hours, and more preferably 2 to 15 hours.

In the present invention, a colored resin particle obtained by the polymerization step is used as a core layer, and a so-called core-shell type (or “capsule type”) colored resin obtained by forming a shell layer different from the core layer on the outer side thereof. It is preferable to use particles.
The core-shell type colored resin particles provide a balance between lowering the fixing temperature of toner and preventing aggregation during storage by coating a core layer made of a material having a low softening point with a material having a higher softening point. Can be taken.

  There is no restriction | limiting in particular as a method of manufacturing the said core-shell type colored resin particle, It can manufacture by a conventionally well-known method. An in situ polymerization method and a phase separation method are preferable from the viewpoint of production efficiency.

A method for producing core-shell type colored resin particles by in situ polymerization will be described below.
By adding a polymerizable monomer for forming a shell layer (polymerizable monomer for shell) and a polymerization initiator for shell into an aqueous dispersion medium in which colored resin particles are dispersed, and performing polymerization. Core-shell type colored resin particles can be obtained.

  As the polymerizable monomer for the shell, the same polymerizable monomer as described above can be used. Among them, it is preferable to use monomers such as styrene and methyl methacrylate that can produce a polymer having a Tg of more than 80 ° C. alone or in combination of two or more.

Examples of the shell polymerization initiator used for the polymerization of the shell polymerizable monomer include potassium persulfate and persulfate metal salts such as ammonium persulfate; 2,2′-azobis (2-methyl-N- (2-hydroxy Water-soluble azo compounds such as ethyl) propionamide) and 2,2′-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide); Mention may be made of initiators.
The addition amount of the polymerization initiator for shell is preferably 0.1 to 30 parts by weight, and more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer for shell.

  The polymerization temperature of the shell layer is preferably 50 ° C. or higher, and more preferably 60 to 95 ° C. The polymerization time for the shell layer is preferably 1 to 20 hours, more preferably 2 to 15 hours.

From the viewpoint of image reproducibility, the volume average particle diameter (Dv ₁ ) of the colored resin particles obtained through the step (1) of obtaining the colored resin particle aqueous dispersion is preferably 4 to 10 μm, and preferably 5 to 9 μm. It is more preferable that
When the volume average particle diameter (Dv ₁ ) of the colored resin particles is less than the above range, the fluidity of the obtained toner is lowered, the image quality is liable to be deteriorated due to fogging, and the printing performance is adversely affected. May affect. On the other hand, when the volume average particle diameter (Dv ₁ ) of the colored resin particles exceeds the above range, the resolution of the obtained image tends to be lowered, and print performance may be adversely affected.

The average circularity of the colored resin particles is preferably 0.95 to 0.995, and more preferably 0.97 to 0.995, from the viewpoint of image reproducibility.
When the average circularity of the colored resin particles is less than the above range, the fine line reproducibility of the obtained toner print tends to be lowered, and the print performance may be adversely affected.

In the present invention, “circularity” is defined as a value obtained by dividing the circumference of a circle having the same projected area as the particle image by the circumference of the projected image of the particle. The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particles, and is an index indicating the degree of unevenness of the colored resin particles. The average circularity is determined by the colored resin particles. 1 is shown in the case of a perfect sphere, and the value becomes smaller as the surface shape of the colored resin particles becomes more complicated. For the average circularity, the circularity (Ci) of each particle measured for a particle group having a circle-equivalent diameter of 0.4 μm or more was obtained for each of n particles from the following calculation formula 1, and then averaged from the following calculation formula 2. Obtain the circularity (Ca).
Formula 1:
Circularity (Ci) = perimeter of circle equal to projected area of particle / perimeter of projected particle image

In the above calculation formula 2, fi is the frequency of particles having a circularity (Ci).
The circularity can be measured using a flow type particle image analyzer “FPIA-2000”, “FPIA-2100”, “FPIA-3000”, etc. manufactured by Sysmex Corporation.

(2) Washing step This step includes (2-2) a washing step with washing water, preferably (2-1) a pH adjustment step, and the desired washing can be performed through each step.

(2-1) pH adjustment step The colored resin particle aqueous dispersion obtained through the step (1) of obtaining the colored resin particle aqueous dispersion is an acid or It is preferable to remove and wash the dispersion stabilizer by adjusting the pH of the colored resin particle aqueous dispersion by adding an alkali.

  When an acid-soluble dispersion stabilizer is used, the pH is adjusted by adding an acid to the colored resin particle aqueous dispersion, and unnecessary dispersion stabilization remaining in the colored resin particle aqueous dispersion is performed. The agent can be dissolved in an aqueous system.

  The acid added when a dispersion stabilizer soluble in acid is used is not particularly limited, and examples thereof include inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid; organic acids such as formic acid and acetic acid; Of these, sulfuric acid is particularly preferably used because of its high removal efficiency of the dispersion stabilizer and low burden on the production equipment.

(2-2) Washing step with washing water The colored resin particle aqueous dispersion obtained through the above (2-1) pH adjustment step is subjected to solid-liquid separation and washing with washing water using a filtration device or a centrifugal separator. By repeating the above, the degree of cleaning can be increased. Washing the colored resin particles with the washing water until the electrical conductivity of the filtrate obtained by filtering the colored resin particle aqueous dispersion adjusted to a predetermined solid content concentration after washing with the washing water becomes 1000 μS / cm or less. The desired colored resin particle aqueous dispersion having a high degree of cleaning can be prepared.

  As the washing water, tap water, distilled water, and ion exchange water can be used, and among these, ion exchange water is preferable. These washing waters can also contain water-soluble organic solvents such as alcohol.

  Examples of the filtration device include pressure filtration devices such as a pressure Nutsche type, a filter press type, and a roll press type; vacuum filtration devices such as a vacuum Nutsche type and a belt filter type; and the like. These filtration devices may be used alone or in combination of two or more.

Examples of the centrifugal separator include a centrifugal sedimentation apparatus such as a basket type, a separation plate type, and a decanter type; and a centrifugal dehydration apparatus such as a siphon type, a basket type, and a screw type. These centrifuges may be used alone or in combination of two or more.
Furthermore, you may use combining a filtration apparatus and a centrifuge.

In the present invention, the electrical conductivity of the filtrate can be used as an index when determining the level of cleaning degree of the colored resin particles.
The electrical conductivity of the filtrate obtained by filtering the prepared colored resin particle aqueous dispersion is 1-1000 μS / cm, preferably 3-800 μS / cm, more preferably 5-600 μS / cm. .

When the electric conductivity of the filtrate exceeds the above range, the level of washing degree of the colored resin particles is not appropriate, and the toner produced as it is does not exhibit the charging characteristics suitably, and the image quality due to fog or the like is poor. Deterioration tends to occur and print performance may be adversely affected.
For this reason, when the electrical conductivity of the said filtrate exceeds the said range, it is necessary to raise the level of the washing | cleaning degree of a colored resin particle.
The electrical conductivity can be measured using, for example, an electrical conductivity meter (trade name: ES-12) manufactured by Horiba, Ltd.

  Even when the solid content concentration of the prepared colored resin particle aqueous dispersion is adjusted to a high solid content concentration of 30% or more, which is difficult to apply by conventional liquid feeding means, the liquid feeding means suitable for the present invention should be used. Therefore, even when the solid resin concentration is adjusted to a low solid content concentration of 10% or less, which is difficult to apply with a conventional dryer, the pulse specified in the present invention can be smoothly delivered. By using a shock wave dryer, desired colored resin particles having a low water content of a specific amount or less can be obtained, so the solid content concentration of the colored resin particle aqueous dispersion is not particularly limited.

The solid content concentration of the suitable colored resin particle aqueous dispersion is preferably 25 to 70% by weight, more preferably 30 to 65% by weight from the viewpoint that the fuel consumption for drying can be reduced. More preferably, it is 35 to 60% by weight.
The solid content concentration of the colored resin particle aqueous dispersion can be determined by subtracting the amount of water (water content) contained in the colored resin particle aqueous dispersion from 100.

  When the solid content concentration of the colored resin particle aqueous dispersion is less than the above range, the amount of water contained in the colored resin particle aqueous dispersion is too large. In order to obtain the desired colored resin particles having a low water content, a large amount of energy is required, and the fuel efficiency for drying may increase.

(3) Drying step In this step, the prepared colored resin particle aqueous dispersion obtained through the above (2) washing step is supplied to a pulse shock wave drier and dried to obtain a water content of a specific amount or less. Desired colored resin particles having a low rate can be obtained.

  The liquid feeding means for supplying the prepared colored resin particle aqueous dispersion to the pulse shock wave dryer smoothly feeds the liquid without causing problems such as aggregation and / or fusion of the colored resin particles. If possible, it is not particularly limited. For example, centrifugal pumps such as centrifugal pumps and axial flow pumps; volume reciprocating pumps such as plunger pumps and diaphragm pumps; gear pumps, screw pumps, vane pumps, and mono pumps A positive displacement pump or the like can be used as the liquid feeding means.

When a colored resin particle aqueous dispersion containing a relatively large amount of solids having a solid content concentration of 30% by weight or more is fed, the colored resin particles are not fused or cracked due to stress on the colored resin particles. Since the liquid feeding can be performed smoothly, a positive displacement rotary pump is preferably used as the liquid feeding means.
As the positive displacement pump suitably used in the present invention, various commercially available products can be used, for example, a Heisin Mono pump (trade name) manufactured by Hyojin Equipment Co., Ltd.

  In the present invention, the “pulse shock wave dryer” means that a dry object is brought into contact with a pulse shock wave to separate and evaporate liquid (moisture) from the dry object instantly (in a short time) at a low temperature. It means a dryer that can be used.

  According to the drying method using the pulse shock wave of the present invention, since desired drying is possible in a relatively low temperature range of 40 to 70 ° C., aggregation and / or fusion of colored resin particles due to the heat of the dryer The desired colored resin particles having a low moisture content of a specific amount or less can be obtained without causing the colored resin particles to be fused into the dryer.

In the drying process of the present invention, by using a “pulse shock wave dryer”, even a colored resin particle aqueous dispersion having a relatively low solid content (relatively high water content) can be efficiently dried. Even if there is little fuel consumption for this, the colored resin particle with a low moisture content below a specific amount can be obtained.
For this reason, according to the toner manufacturing method of the present invention, it is possible to omit the dehydration step, which is essential in the conventional toner manufacturing method, and the number of steps of the manufacturing method can be reduced, and also in terms of equipment. Simplified and economical.

  As the pulse shock wave dryer used in the present invention, various commercially available dryers can be used, for example, High Palcon type 25 type (trade name) manufactured by Partec Co., Ltd.

The water content of the colored resin particles after drying is 0.5% by weight or less, preferably 0.4% by weight or less, more preferably 0.2% by weight or less.
The water content is a value measured using a Karl Fischer reagent.
When the water content of the colored resin particles after drying exceeds the above range, it becomes difficult to properly express the charging characteristics of the toner at the time of printing the toner, and the image quality is likely to deteriorate due to fog or the like. The printing performance may be adversely affected.

(4) Colored resin particles The colored resin particles obtained through the above (3) drying step will be described.
The colored resin particles described below include both core-shell type and non-core type.

The volume average particle diameter (Dv) of the colored resin particles constituting the toner is preferably 4 to 10 μm and more preferably 5 to 9 μm from the viewpoint of image reproducibility.
When the volume average particle diameter Dv of the colored resin particles is less than the above range, the fluidity of the toner is lowered, the image quality is liable to be deteriorated due to fogging, and the printing performance may be adversely affected. On the other hand, when the volume average particle diameter Dv of the colored resin particles exceeds the above range, the resolution of the obtained image tends to be lowered, and the printing performance may be adversely affected.

The particle size distribution (Dv / Dn), which is the ratio of the volume average particle size (Dv) and the number average particle size (Dn), of the colored resin particles is 1 to 1.25 from the viewpoint of image reproducibility. It is preferable that it is 1 to 1.2.
When the particle size distribution (Dv / Dn) of the colored resin particles exceeds the above range, the fluidity of the toner is lowered, the image quality is liable to be deteriorated due to fogging, and the printing performance may be adversely affected. is there.
In addition, the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the colored resin particles are values measured using a particle diameter measuring machine.

The average circularity of the colored resin particles is preferably 0.95 to 0.995, and more preferably 0.97 to 0.98, from the viewpoint of image reproducibility.
When the average circularity of the colored resin particles is less than the above range, the fine line reproducibility of toner printing tends to be lowered, and the printing performance may be adversely affected.

(5) Toner The colored resin particles obtained in the present invention may be used as they are, or may be used as colored toner particles and carrier particles (ferrite, iron powder, etc.), but the chargeability, fluidity, and storage of the toner. From the viewpoint of adjusting properties and the like, a high-speed stirrer (for example, a trade name: FM mixer (manufactured by Mitsui Mining Co., Ltd.)) may be used to mix the colored resin particles and the external additive to form a single component toner After mixing the colored resin particles and the external additive, the carrier particles may be further mixed to form a two-component developer.

External additives include inorganic fine particles made of silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, cerium oxide, etc .; polymethyl methacrylate resin, silicone resin, melamine resin, etc. Organic fine particles; and the like. Among these, inorganic fine particles are preferable, and among inorganic fine particles, silica and titanium oxide are preferable, and silica is particularly preferable. The above external additives can be used alone, but it is preferable to use two or more types in combination.
In the present invention, it is desirable to use the external additive in a proportion of usually 0.1 to 6 parts by weight, preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the colored resin particles.

The volume resistivity of the toner produced in the present invention is preferably 10.7 to 11.9 (log (Ω · cm)), preferably 10.8 to 11.8 (log (Ω · cm)). More preferably, it is 10.9 to 11.7 (log (Ω · cm)).
The volume resistivity can be measured using, for example, a dielectric loss measuring device (trade name: TRS-10 type) manufactured by Ando Electric Co., Ltd.

  When the volume specific resistance of the toner is less than the above range, the charge holding power as the toner is too low, so that it is difficult to transfer the toner image suitably to the transfer material in the transfer process of the image forming method. Deterioration of image quality due to fog or the like is likely to occur, and print performance may be adversely affected. On the other hand, when the volume specific resistance of the toner exceeds the above range, the charge holding power as the toner is too high, and therefore, the transfer residual toner that could not be transferred can be removed in the cleaning process of the image forming method. This makes it difficult to cause image quality deterioration due to fog or the like, and may adversely affect printing performance.

The absolute value of the blow-off charge amount of the toner produced in the present invention is preferably 20 to 90 μC / g, more preferably 25 to 85 μC / g, and further preferably 30 to 80 μC / g. .
The blow-off charge amount is a value measured using a blow-off charge amount measuring device based on the blow-off method. For example, the blow-off charge amount is measured using a blow-off charge amount measuring device (trade name: TR8652) manufactured by Advantest. be able to.

  When the toner blow-off charge amount is less than the above range, an increase in the reversely charged toner or the like is likely to cause image quality deterioration due to fog or the like, which may adversely affect printing performance. On the other hand, when the blow-off charge amount of the toner exceeds the above range, the adhesive force to the photoconductor becomes too strong and the image quality is liable to deteriorate due to an increase in the residual toner. May adversely affect performance.

  The toner manufactured through the steps (1) to (5) is washed in the washing step until the electrical conductivity of the filtrate of the colored resin particle aqueous dispersion becomes a specific amount or less, and then the drying step. In the above, the aqueous dispersion of colored resin particles having a high degree of cleaning is supplied to a pulse shock wave dryer and dried, thereby agglomerating and / or fusing the colored resin particles, and the colored resin particles into the dryer. Highly efficient drying without causing fusion, colored resin particles having a low moisture content below a specific amount can be obtained even with low fuel consumption for drying, excellent productivity, and printing performance It is also an excellent toner.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited only to these examples. Parts and% are based on weight unless otherwise specified.
The test methods performed in the examples and comparative examples are as follows.

(Test method)
(1) Measurement of electrical conductivity About the filtrate obtained in the washing process, the electrical conductivity of the filtrate was measured using an electrical conductivity meter (trade name: ES-12, manufactured by Horiba, Ltd.), and the following formula 3 was used to determine the electrical conductivity of the substantial filtrate.
Formula 3:
Electric conductivity of the filtrate (μS / cm) = A−B
A: Electrical conductivity of measured filtrate (μS / cm)
B: Electric conductivity of ion exchange water (μS / cm)

(2) Colored resin particles (2-1) Volume average particle size Dv and particle size distribution Dv / Dn
About 0.1 g of a measurement sample (colored resin particles) was weighed and taken in a beaker, and 0.1 ml of an alkylbenzene sulfonic acid aqueous solution (manufactured by Fuji Film Co., Ltd., trade name: Drywell) was added as a dispersant. Add 10-30 ml of Isoton II (trade name, electrolyte) to the beaker, and disperse with a 20 W (Watt) ultrasonic disperser for 3 minutes. Then, a particle size measuring instrument (Beckman Coulter, product) Name: Multisizer), aperture diameter: 100 μm, medium: Isoton II, number of measured particles; volume average particle diameter (Dv) and number average particle diameter of colored resin particles (100,000) Dn) was measured and the particle size distribution (Dv / Dn) was calculated.

(2-2) Average circularity Into a container, 10 ml of ion-exchanged water is put in advance, 0.02 g of a surfactant (alkylbenzenesulfonic acid) is added as a dispersant, and a measurement sample (colored resin particles) 0. 02 g was added, and dispersion treatment was performed with an ultrasonic disperser at 60 W (Watt) for 3 minutes. The concentration of the colored resin particles at the time of measurement is adjusted to 3,000 to 10,000 particles / μl, and flow type particle images of 1,000 to 10,000 colored resin particles having an equivalent circle diameter of 0.4 μm or more are used. Measurement was performed using an analyzer (trade name: FPIA-2100, manufactured by Simex Corporation). The average circularity was determined from the measured value.
The circularity is shown in the following calculation formula 1, and the average circularity is an average of the circularity.
Formula 1:
(Circularity) = (Perimeter of circle equal to projected area of particle) / (Perimeter of particle projection image)

(2-3) Moisture content The amount of water contained in the colored resin particles obtained in the drying step was determined using a coulometric titration-type moisture measuring device (manufactured by Mitsubishi Kasei Co., Ltd., trade name: CA-100 type) and a moisture vaporizer (Mitsubishi). The water content of the colored resin particles was determined by titrating with a Karl Fischer reagent and measuring the water content.

(3) Toner (3-1) Blow-off charge amount Based on the blow-off method, 9.5 g of manganese ferrite coated with silicone resin and carbon black, which are standard carriers, and 0.5 g of toner are placed in a 30 ml glass container. Rotating and mixing for 30 minutes using a ball mill (trade name: desktop ball mill model V-1M, manufactured by Irie Trading Company), 0.2 g of the obtained carrier mixed sample was precisely weighed, and a blow-off charge amount measuring device (Brand name: TR8652 manufactured by Advantest Corporation) was used to measure the blow-off charge amount (μC) of the carrier mixed sample in a normal temperature and normal humidity (N / N) environment (temperature: 23 ° C., humidity: 50%). .
The blow-off charge amount (μC / g) of the toner is obtained by dividing the measured value of the blow-off charge amount of the carrier mixed sample by the weight of the precisely mixed carrier mixed sample, and further dividing by the weight concentration of the toner. It was calculated by converting per unit weight of toner.

(3-2) Volume Specific Resistance Using 3.6 g of toner, a pressure (100 kg / cm ²⁾ , time: 1 minute using a molding machine (manufactured by Maekawa Test Instruments Co., Ltd., trade name: tablet molding compressor BRM-30) Under the conditions described above, pressure-molding was performed to prepare a disk-shaped measurement sample having a diameter of 5 cm and a thickness of 2 mm.
The electrical resistance of the prepared measurement sample was measured using a dielectric loss measuring device (trade name: TRS-10, manufactured by Ando Electric Co., Ltd.) under the conditions of temperature: 30 ° C., frequency: 1 kHz. The volume resistivity (log (Ω · cm)) was determined.

Example 1
(Step of obtaining colored resin particle aqueous dispersion)
80.5 parts of styrene as monovinyl monomer and 19.5 parts of n-butyl acrylate (Tg of the resulting copolymer = 55 ° C.), polymethacrylate macromonomer (manufactured by Toagosei Co., Ltd., product) Name: AA6, 0.3 part of polymer obtained (Tg = 94 ° C.) 0.3 part, cross-linkable polymerizable monomer 0.5 part divinylbenzene, molecular weight regulator t-dodecyl mercaptan 1.2 part, and black As a colorant, 7 parts of carbon black (trade name: # 25B, manufactured by Mitsubishi Chemical Corporation) was wet-ground using a media type disperser.

  In the mixture obtained by the wet pulverization, 1 part of a charge control resin (manufactured by Fujikura Kasei Co., Ltd., trade name: Acrybase FCA-207P, styrene / acrylic resin) as a charge control agent, and ester wax (NOF) as a release agent 5 parts by company, trade name: WEP-7) were added, mixed and dissolved to obtain a polymerizable monomer composition for core.

  On the other hand, at room temperature (25 ° C.), an aqueous solution in which 10.2 parts of magnesium chloride was dissolved in 250 parts of ion-exchanged water and an aqueous solution in which 6.2 parts of sodium hydroxide were dissolved in 50 parts of ion-exchanged water were stirred. By gradually adding, a dispersion of magnesium hydroxide colloid was prepared.

  A part of the resulting dispersion of the magnesium hydroxide colloid was collected, and the particle size distribution of the magnesium hydroxide colloid was measured using a particle size distribution measuring device (trade name: SALD, manufactured by Shimadzu Corporation). The particle diameters of D50 (50% cumulative value of number particle size distribution) were 0.35 μm and D90 (90% cumulative value of number particle size distribution) were 0.62 μm.

  On the other hand, 2 parts of methyl methacrylate (Tg = 105 ° C. of the resulting polymer) and 65 parts of water were finely dispersed using an ultrasonic emulsifier, and an aqueous dispersion of a polymerizable monomer for shells. Got.

  A part of the obtained aqueous dispersion of the polymerizable monomer for shell was collected, and the particle size distribution of the polymerizable monomer for shell was measured using a particle size distribution measuring instrument (trade name: manufactured by Shimadzu Corporation). As a result of measurement using SALD, D90 (90% cumulative value of the number particle size distribution) was 1.6 μm.

  The core polymerizable monomer composition is charged into the magnesium hydroxide colloid dispersion (4.0 parts of colloid) obtained above at room temperature (25 ° C.) until the droplets are stabilized. Stir. Thereto, 6 parts of t-butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name: Perbutyl IB) was added as a polymerization initiator, and then an in-line type emulsifying disperser (manufactured by Ebara Corporation, product) Name: Ebara Milder MDN303V), dispersion is performed with high shear stirring until the suspension (polymerizable monomer composition dispersion) circulates 10 times at a rotation speed of 15,000 rpm. A droplet of the functional monomer composition was formed.

  A suspension (polymerizable monomer composition dispersion) in which droplets of the polymerizable monomer composition obtained as described above are dispersed is charged into a reactor equipped with a stirring blade and heated to 85 ° C. Warm to initiate the polymerization reaction. When the polymerization conversion rate reached approximately 100%, 2,2′-azobis (2-methyl-N- (2-hydroxy) as a shell polymerization initiator was added to the aqueous dispersion of the shell polymerizable monomer. (Ethyl) -propionamide) (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086, water-soluble) 0.3 part was dissolved and added to the reactor, and the polymerization reaction was continued at 85 ° C. for 4 hours. The reaction was stopped by cooling with water to obtain an aqueous dispersion of colored resin particles having a core-shell structure.

A part of the obtained colored resin particle aqueous dispersion was collected, and the volume average particle size (Dv ₁ ), particle size distribution (Dv ₁ / Dn ₁ ), and average circularity of the colored resin particles were measured.

(Washing process)
The colored resin particle aqueous dispersion obtained above was added dropwise at room temperature (25 ° C.) while stirring sulfuric acid to adjust the pH to 4 to 5, and left for 10 minutes.
Next, the pH-adjusted colored resin particle aqueous dispersion was subjected to a pressure filter (manufactured by Advantech, product name: UST-239-10-) using a filter paper (manufactured by Advantech Toyo Co., Ltd., product name: No. 5C). UH) was used for filtration separation to form wet colored resin particles (wet cake).

  Next, 400 parts of ion-exchanged water (electric conductivity: 0.5 μS / cm) was added to the wet colored resin particles (wet cake) formed on the filter paper to wash the colored resin particles. The colored resin particles were repeatedly washed with the ion-exchanged water, and washed with ion-exchanged water twice in total to form wet colored resin particles (wet cake).

  The solid content concentration of the formed wet cake was 82% by weight (water content: 18% by weight).

  The wet colored resin particles (wet cake) obtained as described above are collected, and the collected wet cake is subjected to ion-exchanged water (electricity) so that the solid content concentration is 35% (water content: 65%). Conductivity: 0.5 μS / cm) was redispersed to adjust the solid content concentration, and a colored resin particle aqueous dispersion was prepared.

  In addition, a part of the obtained colored resin particle aqueous dispersion was collected, and the electrical conductivity of the filtrate obtained by filtration was measured using a filter paper (trade name: No. 5C, manufactured by Advantech Toyo Co., Ltd.). However, it was 55 μS / cm.

(Drying process)
The colored resin particle aqueous dispersion (raw material) obtained as described above was subjected to a pulse shock wave dryer (manufactured by Partec Co., Ltd., trade name) using a MONO pump (manufactured by Hyoshin Equipment Co., Ltd., trade name: Heishin Monono Pump 2NBL06F) as a liquid feeding means. : High Palcon Model 25) and dried under the operating conditions of the dryer shown in Table 1 to obtain colored resin particles. At this time, the degree of fusion of the toner to the wall surface in the dryer was visually determined.

  A part of the obtained colored resin particles was collected, and the volume average particle size (Dv), particle size distribution (Dv / Dn), and average circularity of the colored resin particles were measured. A part of the obtained colored resin particles was collected and the water content of the colored resin particles was measured, and it was 0.08% by weight.

To 100 parts of the colored resin particles obtained as described above, 0.5 part of silica fine particles having a BET specific surface area of 200 m ² / g and 1.5 parts of silica fine particles having a BET specific surface area of 50 m ² / g are added, Using a high-speed stirrer (trade name: Henschel mixer, manufactured by Mitsui Mining Co., Ltd.), the mixture was stirred for 6 minutes at a peripheral speed of 35 m / s and externally added to prepare the toner of Example 1, which was used for the test. .

(Example 2)
In the cleaning process of Example 1, the number of times of cleaning with ion-exchanged water was changed from 2 to 3, and in the drying process, except that the operating conditions of the dryer were changed as shown in Table 1. The toner of Example 2 was prepared in the same manner as in Example 1 and used for the test.

(Example 3)
In the washing step of Example 1, the solid content concentration was changed from 35% by weight (water content: 65% by weight) to 45% by weight (water content: 55% by weight). A toner of Example 3 was produced in the same manner as in Example 1 except that the conditions were changed as shown in Table 1, and were subjected to the test.

Example 4
In the washing process of Example 1, the solid content concentration was changed from 35% by weight (water content: 65% by weight) to 20% by weight (water content: 80% by weight). A toner of Example 4 was produced in the same manner as in Example 1 except that the conditions were changed as shown in Table 1, and were subjected to the test.

(Comparative Example 1)
In the cleaning process of Example 1, the number of times of cleaning with ion-exchanged water was changed from 2 to 1, and in the drying process, except that the operating conditions of the dryer were changed as shown in Table 1. In the same manner as in Example 1, a toner of Comparative Example 1 was produced and used for the test.

(Comparative Example 2)
In the washing step of Example 1, a wet cake (solid content concentration: 82% by weight (water content: 18% by weight)) formed by washing with ion exchange water twice in total was collected, and in the drying step, The recovered wet cake (raw material) is supplied to a hot air dryer (trade name: Spin Flash Dryer, manufactured by Anhydro Co., Ltd.) using a screw feeder, and the operating conditions of the dryer are changed as shown in Table 1. A toner of Comparative Example 2 was produced in the same manner as in Example 1 except that it was subjected to the test.
In addition, the measurement of the electrical conductivity of the filtrate performed in Comparative Example 2 was performed for a part of the wet cake (solid content concentration: 82% by weight) recovered in the washing step, and the same solid content as in Example 1 was used. The concentration was adjusted to 35% by weight, and the electrical conductivity of the filtrate was measured in the same manner as in Example 1. As a result, it was 55 μS / cm.

(Comparative Example 3)
In the drying process of Comparative Example 2, the toner of Comparative Example 3 was produced in the same manner as Comparative Example 2 except that the operating conditions of the dryer were changed as shown in Table 1, and were used for the test.

(Dryer operating conditions)
Table 1 shows the operating conditions of the dryer used in the drying step of each example and comparative example.

The notes in Table 1 are as follows.
* 1: Moisture content of raw material; (feed amount of raw material) x (water content of raw material)
* 2: Solid content of raw material; (feed amount of raw material)-(water content of raw material)
* 3: Dry fuel consumption per solid content; (combustion calorific value) / (solid content of raw material)
* 4: Dry fuel consumption per water content; (combustion calorific value) / (water content of raw material)

(result)
Table 2 shows the test results of the toners produced in each Example and Comparative Example.

(Summary of results)
From the test results described in Table 2, the following can be understood.
The toner of Comparative Example 1 was manufactured without being sufficiently washed until the electrical conductivity of the filtrate of the colored resin particle aqueous dispersion became a specific amount or less in the washing step. The Dv of the colored resin particles is a toner that is enlarged due to the influence of residual impurities and may adversely affect the printing performance of the toner.

  The toner of Comparative Example 2 is efficiently dried by confirming the fusion of the colored resin particles into the dryer due to being manufactured using a dryer other than those specified in the present invention in the drying step. The Dv of the colored resin particles after drying was a toner that may be enlarged due to the aggregation and / or fusion of the colored resin particles, which may adversely affect the printing performance.

  The toner of Comparative Example 3 was produced by using the same dryer as that of Comparative Example 2 in the drying process and by setting the temperature in the dryer lower than that of Comparative Example 2. The toner has a water content higher than a specific amount and may adversely affect printing performance.

  On the other hand, the toners of Examples 1 to 3 were produced through the washing step and the drying step specified in the present invention, and thus the aggregation and fusion of the colored resin particles, and the drying of the colored resin particles. The toner is capable of high-efficiency drying without causing fusion in the machine, low fuel consumption for drying, excellent productivity, and excellent printing performance.

  Further, the toner of Example 4 was produced through the washing process and the drying process specified in the present invention, and thus, the aggregation and fusion of the colored resin particles, and the fusion of the colored resin particles in the dryer. In the washing step, the solid content concentration of the prepared colored resin particle aqueous dispersion was not more than the preferred range, so that the drying can be performed efficiently. The fuel consumption is slightly higher.

Claims (6)

Forming colored resin particles by a wet method to obtain an aqueous dispersion of colored resin particles, and washing the colored resin particles in the aqueous dispersion of colored resin particles with washing water to obtain an aqueous dispersion of colored resin particles In a toner production method including a washing step and a drying step of drying the colored resin particle aqueous dispersion to obtain colored resin particles,
In the washing step, the colored resin particles are washed until the electrical conductivity of the filtrate obtained by filtering the aqueous dispersion of colored resin particles adjusted to a predetermined solid content concentration is 1000 μS / cm or less. Prepare an aqueous dispersion,
In the drying step, the prepared colored resin particle aqueous dispersion is supplied to a pulse shock wave dryer for drying, and a toner having a water content of the colored resin particles after drying of 0.5% by weight or less is produced. Method.   2. The toner manufacturing method according to claim 1, wherein, in the washing step, the solid content concentration of the prepared colored resin particle aqueous dispersion is 25 to 70 wt%.   In the step of obtaining the colored resin particle aqueous dispersion, at least a polymerizable monomer and a polymerizable monomer composition containing a colorant are dispersed in an aqueous dispersion medium containing a dispersion stabilizer, The method for producing a toner according to claim 1 or 2, wherein the colored resin particles are formed by polymerization.   The method for producing a toner according to claim 3, wherein the dispersion stabilizer is a metal hydroxide.   The liquid feeding means for supplying the colored resin particle aqueous dispersion prepared in the drying step to a pulse shock wave drier is a volumetric rotary pump according to any one of claims 1 to 4. A method for producing the toner according to the description.   The method for producing a toner according to any one of claims 1 to 5, wherein the washing water is ion-exchanged water.