JP2001092176A - Powder toner and its manufacturing method - Google Patents

Abstract

(57) Abstract: A spherical to substantially spherical powder toner using a polyester resin as a binder resin and exhibiting excellent fixing properties and image properties, and a method for producing the same. The binder resin is a polyester resin having an acid value of 1 to 30, and the weight-average molecular weight in the THF-soluble component of the binder resin measured by GPC is 30,000 or more, and the weight-average molecular weight / number-average molecular weight is 12 or more. 0.5% area ratio with a molecular weight of 600,000 or more
As described above, a spherical to substantially spherical powder toner having an average circularity of 0.97 or more, characterized in that an area ratio of a molecular weight of 10,000 or less is 20 to 80%. This means that a mixture of a binder resin and a colorant is mixed with an aqueous medium in the presence of a basic neutralizing agent and emulsified to form resin particles containing the colorant and the like, and the particles are separated from the liquid medium. It can be suitably manufactured by drying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder toner for developing an electrostatic latent image used in an electrophotographic copying machine, a printer, a facsimile, and the like, and a method for producing the same. Further, the present powder toner can be suitably used for development of a so-called toner jet printer or the like.

[0002]

2. Description of the Related Art In recent years, in electrophotographic copying machines, printers, and faxes, toners have been used to improve the quality of printed images, reduce the cost and size of machines, and save power and resources. On the other hand, the following needs are increasing. That is, the resolution and gradation of a printed image are improved, the toner layer is made thinner, the amount of waste toner is reduced,
Smaller toner particle size and spherical shape to reduce toner consumption per page, lowering of fixing temperature to reduce power consumption, oilless fixing to simplify machine, etc. Improves hue, transparency and gloss, and has a negative effect on human health.
OC (volatile organic compound) reduction, and the like.

[0003] Even in the case of a powder toner that has been used for a long time, the particle size can be basically reduced. However, as the particle size decreases, the ratio of the colorant or wax exposed on the surface of the toner particles is reduced. Increase makes charging control difficult.
Powder fluidity deteriorates due to irregular shape of toner particles,
Problems such as an increase in the energy cost required for production occur, and it is practically difficult to sufficiently satisfy the above-mentioned needs with an irregular-shaped toner obtained by a pulverization method.

[0004] For this purpose, development of spherical toner having a small particle size by a polymerization method or an emulsification dispersion method has been actively conducted. Various methods are known for producing a toner by a polymerization method.A monomer, a polymerization initiator, a colorant, a charge control agent, and the like are uniformly dissolved and dispersed, and this is dispersed in an aqueous medium containing a dispersion stabilizer. A suspension polymerization method has been widely practiced in which oil droplets are added by stirring to form oil droplets, and the temperature is raised to carry out a polymerization reaction to obtain toner particles. Although the polymerization method does not pose a problem of reducing the particle size or spheroidizing, the main component of the binder resin is limited to a vinyl polymer capable of radical polymerization, and toner particles made of polyester resin or epoxy resin suitable for color toners etc. Cannot be produced by the suspension polymerization method. Further, in the polymerization method, there is a problem that it is difficult to reduce VOC (a volatile organic compound composed of an unreacted monomer and the like), and improvement is desired.

On the other hand, a method for producing a toner by the emulsification dispersion method is as follows.
As disclosed in JP-A-5-66600 and JP-A-8-21655, a method in which a mixture of a binder resin and a colorant is mixed with an aqueous medium and emulsified to obtain toner particles, similar to the polymerization method In addition to being able to easily cope with the reduction of toner particle size and spheroidization, the type of binder resin to be used can be selected widely, compared with the polymerization method, the VOC can be easily reduced, and the concentration of the colorant or the like is low. It is easy to arbitrarily change from a high concentration to a high concentration.

[0006] On the other hand, polyester resins are more preferable than styrene acrylic resins as a binder resin for toner which lowers the fixing temperature or sharply melts at the time of fixing and tends to have a smooth image surface. It is generally known that it is preferable to use a polyester resin having excellent flexibility. As described above, since a polyester resin cannot be used as a main component of a binder resin in the polymerization method, a spherical to substantially spherical small particle size toner using a polyester resin as a binder resin by an emulsification dispersion method has attracted attention in recent years.

[0007] However, the polyester resin toner obtained by the emulsification dispersion method, which has hitherto been carried out, uses a relatively low molecular weight linear resin as a binder resin. Liquid application is essential, and in addition to maintenance issues,
Since the silicone oil or the like is transferred to the printing paper or the OHP sheet, there is a problem that writing after printing is hindered, or the oil becomes sticky. There is also a problem that the peel strength is not always sufficient depending on the use.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat roller fixing system which is capable of performing low-temperature fixing without using an anti-offset liquid and has excellent image quality. Provides a polyester resin toner having a small particle size and a method for producing the same.

[0009]

Means for Solving the Problems The present inventors have intensively studied the molecular weight distribution, structure, acid value, wax (release agent) and the like of a polyester resin used as a binder resin. The present invention was found by finding a spherical or nearly spherical toner having high image quality and a suitable production method thereof.

That is, according to the present invention, the binder resin has an acid value of 1 to 30.
In the polyester resin, the weight-average molecular weight in gel permeation chromatography measurement of the tetrahydrofuran-soluble component of the binder resin is 30,000 or more, the weight-average molecular weight / number-average molecular weight is 12 or more, and the area ratio of the molecular weight is 600,000 or more. The area ratio of 0.5% or more and the molecular weight of 10,000 or less is 20 to 80.
% Or an average circularity defined by (perimeter of a circle having the same area as the projected area of the particle) / (average circularity defined by (perimeter of the projected image of the particle)) of 0.97 or more. Powder toner.

[0011] In addition, as a production method, a mixture containing a binder resin and a colorant as essential components is mixed with an aqueous medium and emulsified to form colorant-containing resin particles. It is suitably manufactured by separating from the medium and drying.

When a resin having a self-water dispersibility by neutralizing an acid group contained therein as a binder resin is used, a mixture containing a binder resin and a colorant as essential components is mixed with a base. It can be suitably manufactured by performing a method of mixing and emulsifying with an aqueous medium in the presence of a neutralizing agent.

Further, as the binder resin, it is preferable to use a blend resin of a crosslinked polyester resin and a linear polyester resin.

The powder toner of the present invention preferably contains a wax (release agent).

Hereinafter, the present invention will be described in more detail.

The polyester resin used as the binder resin of the powder toner of the present invention is synthesized by dehydrating and condensing a polybasic acid and a polyhydric alcohol.

Examples of polybasic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and naphthalenedicarboxylic acid; maleic anhydride, fumaric acid, and succinic acid. ,
Examples include aliphatic carboxylic acids such as alkenyl succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. One or more of these polybasic acids can be used. Among these polybasic acids, it is preferable to use an aromatic carboxylic acid, and a trivalent or higher carboxylic acid (trimellitic acid) together with a dicarboxylic acid to obtain a crosslinked structure or a branched structure in order to secure good fixability. Or an acid anhydride thereof).

Examples of polyhydric alcohols include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, cyclohexanediol, cyclohexanedimethanol, water Examples include alicyclic diols such as added bisphenol A, aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A. One or more of these polyhydric alcohols can be used.
Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among them, aromatic diol is more preferable. In order to ensure good fixability, it is preferable to use a trihydric or higher polyhydric alcohol (trimethylolpropane, pentaerythritol, etc.) together with a diol in order to form a crosslinked structure or a branched structure.

In addition, a monocarboxylic acid and / or a monoalcohol is further added to the polyester resin obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol, and a hydroxyl group and / or a carboxyl group at a polymerization terminal are added. May be esterified to adjust the acid value of the polyester resin. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, and propionic anhydride, and examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, and trifluoroethanol. , Trichloroethanol, hexafluoroisopropanol, phenol and the like.

The polyester resin can be produced by subjecting the above polyhydric alcohol and polycarboxylic acid to a condensation reaction according to a conventional method. For example, the polyhydric alcohol and the polycarboxylic acid are mixed in a reaction vessel equipped with a thermometer, a stirrer, and a falling condenser, and heated at 150 to 250 ° C. in the presence of an inert gas (such as nitrogen gas). It can be produced by continuously removing by-product low-molecular compounds out of the reaction system, stopping the reaction when a predetermined acid value is reached, cooling, and obtaining the desired reactant.

A catalyst may be added to the synthesis of the polyester resin. Examples of the catalyst used include esterification catalysts such as organic metals such as dibutyltin dilaurate and dibutyltin oxide and metal alkoxides such as tetrabutyl titanate. Is mentioned. When the carboxylic acid component used is a lower alkyl ester, metal acetates such as zinc acetate, lead acetate, and magnesium acetate. Metal oxides such as zinc oxide and antimony oxide. A transesterification catalyst such as a metal alkoxide such as tetrabutyl titanate can be used. The amount of such a catalyst is preferably 0.01 to 1% by weight based on the total amount of the raw materials.

The polyester resin, which is a main component of the toner of the present invention, has a weight average molecular weight of 30,000 or more, more preferably, 30,000 as measured by gel permeation chromatography (GPC) of a tetrahydrofuran (THF) soluble component. 37,000 or more, weight average molecular weight Mw
/ The number ratio of components having a number average molecular weight Mn of 12 or more, more preferably 15 or more, and a molecular weight of 600,000 or more is 0.5
% Or more, more preferably 0.7% or more, and the area ratio of the component having a molecular weight of 10,000 or less is 20 to 80%, more preferably 30 to 80%.
It is necessary to satisfy all the conditions of 70% to 70% in order to obtain good fixability.

In the present invention, the molecular weight of the resin is determined by measuring the amount of the soluble matter in THF by using GPC HLC-8120 manufactured by Tosoh and column manufactured by Tosoh TSKgel Super HM-M (15c).
m) Using three tubes, THF solvent (flow rate 0.6 ml / mi)
n, at a temperature of 40 ° C.), and the molecular weight was calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample.

A high molecular weight component having a molecular weight of about 600,000 or more is necessary to ensure hot offset resistance, and the toner of the present invention must contain a resin component having a molecular weight of 600,000 or more. On the other hand, a low molecular weight component having a molecular weight of about 10,000 or less is necessary for lowering the melt viscosity of the toner, exhibiting a sharp melt property and lowering the fixing start temperature, and the toner of the present invention contains a resin component having a molecular weight of 10,000 or less. Inclusion is also essential.
In order to obtain good fixing properties such as oilless fixing, it is necessary that the binder resin has such a broad molecular weight distribution. Also, in the granulation of toner particles by the emulsification dispersion method, the inclusion of a low molecular weight component is also effective in improving the granulation properties. In the toner of the present invention, the content of tetrahydrofuran insoluble matter is 0.01 to 20 with respect to the total amount of the binder resin.
It may be contained in an amount of about% by weight.

As the polyester resin used in the toner of the present invention, one kind of polyester resin which satisfies the above requirements may be used. However, a low-molecular-weight, high-viscosity crosslinked or branched polyester resin may be used. It is practical and preferable from the viewpoint of the production of the resin to blend and use a low-viscosity linear polyester resin having a low molecular weight. here,
A crosslinked resin refers to a resin having a component insoluble in a solvent such as tetrahydrofuran, and a branched resin refers to a resin containing a polyfunctional component having a valency of 3 or more but soluble in a solvent such as tetrahydrofuran. The term "linear resin" means a resin containing no crosslinking agent component. In addition, the high molecular weight resin may have a weight average molecular weight of about 100,000 of a tetrahydrofuran-soluble component and may contain a tetrahydrofuran-insoluble component of about 20% by weight or less. Further, a low molecular weight resin means that the weight average molecular weight is less than about 10,000.

The acid value of the polyester resin (the number of mg of KOH required to neutralize 1 g of the resin) is such that the molecular weight distribution as described above can be easily obtained, and the granulation of toner particles by the emulsification dispersion method is ensured. 1 to 30 mgKOH / g because the toner is easy to maintain and the environmental stability of the resulting toner (the stability of charging when temperature and humidity changes) is easily maintained.
It is preferable that The acid value of the polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester based on the blending ratio and the reaction rate of the raw material polybasic acid and polyhydric alcohol. Alternatively, a polyester having a carboxyl group in the main chain can be obtained by using trimellitic anhydride as the polybasic acid component.

The glass transition temperature of the polyester resin is 3
The temperature is preferably from 5 to 100 ° C, and more preferably from 50 to 80 ° C from the viewpoint of the balance between storage stability and toner fixability. When the glass transition temperature is lower than 35 ° C., the toner tends to be easily blocked during storage or in a developing machine (a phenomenon in which toner particles are aggregated and aggregated). On the other hand, when the glass transition temperature exceeds 100 ° C.,
The fixing temperature of the toner becomes high, which is not preferable.

As the binder resin of the toner of the present invention, it is preferable to use the polyester resin as described above. However, if necessary, if less than 40% by weight of the binder resin, other resins may be used. You may use together. As other resins, for example,
Styrene acrylic resin, epoxy resin, polyamide resin and the like can be mentioned. Even in this case, the acid value of the binder resin as a whole is 1 to 30, and the weight average molecular weight is 30,000 or more, more preferably 37,000, in gel permeation chromatography measurement of the tetrahydrofuran-soluble component.
As described above, the weight-average molecular weight / number-average molecular weight is 12 or more, more preferably 15 or more, and the area ratio of components having a molecular weight of 600,000 or more is 0.5% or more, more preferably 0.7% or more.
It is necessary to satisfy the requirement that the area ratio of the component having a molecular weight of 10,000 or less is 20 to 80%, more preferably 30 to 70%.

It is preferable to use wax (release agent) in the toner of the present invention. Examples of such wax include petroleum wax such as paraffin wax, oxidized paraffin wax and microcrystalline wax, and mineral wax such as montan wax. , Carnauba wax,
Examples include animal and plant waxes such as rice wax, synthetic waxes such as polyolefin wax, oxidized polyolefin wax, and Fischer-Tropsch wax, and ester waxes and ether waxes. Of these, carnauba wax, montan wax and rice wax are particularly suitable for the toner of the present invention.

The melting point of the wax is not particularly limited, but is preferably 150 ° C. or less from the viewpoint of offset resistance, and more preferably 50 to 120 ° C. from the viewpoint of low-temperature fixability and storage stability. preferable. The solid wax may be used as it is, or the wax may be used in an emulsified state. The wax is preferably dispersed in the toner, and is desirably dispersed to an average of 1 μm or less. Further, the content of the wax is preferably 1 to 40% by weight based on the toner. If it is less than 1% by weight, the releasability tends to be insufficient, and if it exceeds 40% by weight, the wax tends to be exposed on the surface of the toner particles, and the chargeability and storage stability tend to decrease.

The colorant that can be used in the toner of the present invention is not particularly limited, and a commonly known colorant can be used. Pigments are preferable, and the following can be exemplified.

Examples of the black pigment include carbon black, cyanine black, aniline black, ferrite, magnetite and the like. Alternatively, the following chromatic pigments prepared so as to be black can be used.

As the yellow pigment, for example, graphite, zinc yellow, cadmium yellow, yellow iron oxide, loess, titanium yellow, naphthol yellow S, Hanza yellow 10G, Hanza yellow 5G, Hanza yellow G, Hanza yellow GR, Hanza yellow A, Hansa Yellow RN, Hansa Yellow R, Pigment Yellow L, Benzidine Yellow, Benzidine Yellow G, Benzidine Yellow GR,
Permanent Yellow NCG, Vulcan First Yellow 5G, Vulcan First Yellow R, Quinoline Yellow Lake, Anslagen Yellow 6GL, Permanent Yellow FGL, Permanent Yellow H10G,
Permanent yellow HR, anthrapyrimidine yellow, other isoindolinone yellow, chromophtal yellow, novo palm yellow H2G, condensed azo yellow, nickel azo yellow, copper azomethine yellow and the like.

Examples of the red pigment include red lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indaslen brilliant orange RK, indaslen brilliant orange GK, benzidine orange G, permanent red 4R, and permanent red BL. , Permanent red F
5RK, Risor Red, Pyrazolone Red, Watching Red, Lake Red C, Lake Red D, Brilliant Carmine 6B, Brilliant Carmine 3B, Rhodamine Lake B, Alizarin Lake, Permanent Carmine FBB, Verinone Orange, Isoindolinone Orange, Anthuanthrone Orange, pyranthrone orange, quinacridone red, quinacridone magenta, quinacridone scarlet, perylene red and the like.

Examples of the blue pigment include cobalt blue, cerulean blue, alkali blue lake, peacock blue lake, fanatone blue 6G, Victoria blue lake, metal-free phthalocyanine blue, copper phthalocyanine blue, fast sky blue, and induslen blue RS. , Indaslen Blue BC, Indico and the like.

The amount of the colorant used is 1 to 50 parts by weight, preferably 3 to 15 parts by weight, per 100 parts by weight of the binder resin.
Parts by weight.

In order to obtain a toner capable of forming an excellent image quality, it is preferable that the toner has a spherical particle shape so that good powder fluidity can be ensured even if the particle diameter is reduced.
In the powder toner of the present invention, an average circularity (an average value of circularity defined by (perimeter of a circle having the same area as the projected area of the particle) / (perimeter of the projected image of the particle)) of 0.97 or more is required. And
0.98 or more is more preferable. This average circularity can also be obtained by taking an SEM (scanning electron microscope) photograph of the toner particles, measuring and calculating the same,
Flow particle image analyzer FPIP manufactured by Toa Medical Electronics Co., Ltd.
It can be easily obtained by using -1000, and was measured by this apparatus in the present invention.

In order to maintain good triboelectric charging performance even when the particle size of the toner is reduced, the colorant and the like must not be exposed on the surface of the toner particles, that is, the toner structure in which the colorant and the like are included in the toner particles. It is effective to The deterioration of the chargeability due to the decrease in the particle size of the toner is also caused by the fact that a part of the contained colorant and other additives (usually wax and charge control agent) is exposed on the surface of the toner particles. That is, even if the content (% by weight) of the colorant or the like is the same, the surface area of the toner particles increases due to the reduction in the particle diameter, and the ratio of the colorant or wax exposed on the surface of the toner particles increases. As a result, the composition of the toner particle surface changes greatly, and the triboelectric charging performance of the toner particles changes greatly, making it difficult to obtain proper charging properties.

In the toner of the present invention and the method for producing the same,
Since the colorant, wax, and the like are included in the binder resin, the charging performance is made uniform, and a good printed image is easily obtained. Whether the colorant, the wax, or the like is not exposed on the surface of the toner particles can be easily determined by, for example, observing the cross section of the particles with a TEM (transmission electron microscope). More specifically, a section obtained by embedding toner particles in a resin and cutting with a microtome is dyed with ruthenium oxide or the like, if necessary, and observed with a TEM. You can see that they are dispersed.

The powder toner of the present invention is obtained by mixing and emulsifying and dispersing a mixture containing a binder resin containing a polyester resin as a main component and a colorant as an essential component with an aqueous medium, thereby reducing the colorant-containing resin particles. It can be produced by forming and then separating the particles from a liquid medium and drying.

The granulation of the polyester resin toner particles by such an emulsification dispersion method can be carried out without a solvent as disclosed in JP-A-9-31502, or can be carried out without a solvent. It can also be performed using an organic solvent as disclosed in US Pat.
In the present invention, any granulation method can be used.

The granulation by the solventless method includes (1) a colored resin melt obtained by heating and melting a kneaded product of an acidic group-containing polyester resin and a colorant, and a basic neutralizer,
Heating, and if necessary, further pressurizing to mix with an aqueous medium heated to a temperature equal to or higher than the softening point of the polyester resin, and (2) maintaining the temperature of the mixture at a temperature equal to or higher than the softening point of the resin. In the meantime, the colored resin melt is finely dispersed in an aqueous medium by mechanical means, and (3) immediately thereafter, rapidly cooled to obtain an aqueous dispersion of toner particles. The solventless method has an advantage that an organic solvent does not need to be used, but has a difficulty in equipment as compared with the solvent method because the emulsification and dispersion are performed at a high temperature and a high pressure.

A method for forming toner particles by an emulsification dispersion method using an organic solvent includes an acid group containing a basic neutralizing agent as disclosed in JP-A-8-21655 and JP-A-10-319639. A method of granulating without using an emulsifier, a dispersion stabilizer, etc. by neutralizing and converting the binder resin into a self-water-dispersible resin.
And a method of granulating using a resin that does not itself disperse in water and using an emulsifier or a dispersion stabilizer, and any method can be used in the present invention.

The self-water-dispersible resin is a resin containing a functional group which can be converted into an anionic form by neutralization. A part of or all of the functional groups which can be hydrophilic is neutralized with a base. Or a liquid medium containing water as a main component), which can form a stable aqueous dispersion without using an emulsifier or a dispersion stabilizer.

Examples of the functional group which can be converted into a hydrophilic group upon neutralization include so-called acidic groups such as a carboxyl group, a phosphoric acid group and a sulfonic acid group. Resins containing these functional groups include styrene resins, (meth) acrylic resins, polyester resins, polyurethane resins,
Epoxy resins and the like can be mentioned.

The neutralizing agent for these acidic groups is not particularly restricted but includes, for example, inorganic bases such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, sodium carbonate, ammonia, and diethylamine, triethylamine. And organic bases such as isopropylamine.

As the polyester resin as the binder resin,
When a polyester resin which does not disperse itself in water as described above, that is, does not have self-water dispersibility, is used, an emulsifier and / or a dispersion stabilizer is added to the resin solution and / or an aqueous medium mixed therewith. It is necessary to use it.

As the dispersion stabilizer, a water-soluble polymer compound is preferable, and examples thereof include polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose and the like. Examples of the emulsifier include various nonionic surfactants such as polyoxyethylene alkylphenol ether, and various anionic or cationic surfactants such as sodium alkylbenzenesulfonate. Of course, two or more kinds of emulsifiers may be used in combination, two or more kinds of dispersion stabilizers may be used in combination, or an emulsifier and a dispersion stabilizer may be used in combination. It is common to use an emulsifier in combination.

In this case, when an emulsifier or a dispersion stabilizer is used, its concentration in the aqueous medium is suitably adjusted to about 0.5 to 3% by weight.

Further, even when a resin which can be made self-water dispersible by neutralization as described above is used, if necessary, the emulsifier and / or dispersion stability may be used as long as the effects of the present invention are not impaired. Agents may be used.

A method of granulating without using an emulsifier or a dispersion stabilizer by neutralizing an acid group contained with a basic neutralizing agent and changing the binder resin to a self-water-dispersible resin; In the case of using a polyester resin containing a high molecular weight component, the method of granulating using a stabilizer is to neutralize the acidic groups contained with a basic neutralizing agent and change to a self-water dispersible resin. In the present invention, the former is preferred because, for example, the granulation properties are good, and if an emulsifier or a dispersion stabilizer is used, washing with water or the like is difficult to remove the emulsifier or the dispersion stabilizer after granulation. Is more preferred than the latter.

Examples of the organic solvent used for dissolving the binder resin and dispersing the colorant include hydrocarbons such as pentane, hexane, heptane, benzene, toluene, xylene, cyclohexane and petroleum ether; methylene chloride; Halogenated hydrocarbons such as chloroform, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene and carbon tetrachloride; alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol and butanol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone Esters such as ethyl acetate and butyl acetate, and the like, and two or more of these may be used as a mixture.

The kneaded material in which a colorant, wax and the like are dispersed in a binder resin may be a known and commonly used method, and is not particularly limited. First, these powders are mixed, and then a twin-screw extruder, a kneader, A method of sufficiently kneading using any of the rolls or the like may be used. In such a kneading step, the high molecular weight component of the binder resin may be cut off. Therefore, as in the case of the toner of the present invention, in order to produce a toner composed of a binder resin having a specific range of molecular weight, a binder is required. It is preferable to select a raw material resin to be used by previously recognizing a change in molecular weight during kneading of the resin.

The kneaded product obtained by dispersing the colorant, wax and the like in the binder resin thus obtained can be used as it is in the emulsifying and dispersing step by the above-mentioned solvent-free method. After being dissolved and dispersed, it is used in the emulsification and dispersion step.

Another method for preparing an organic solvent solution of a kneaded material in which a colorant, wax, and the like are dispersed in a binder resin is to dissolve the binder resin in an organic solvent, add a colorant and wax thereto, and add ), A ball mill, a bead mill, a sand mill, a continuous bead mill, and other common mixers / dispersers, which are suitable for use in the present invention.

Apparatuses for mixing and emulsifying and dispersing a kneaded product of a binder resin and a colorant, or an organic solvent solution thereof, and an aqueous medium include, for example, a homomixer (Tokiki Kika Kogyo Co., Ltd.), Stirrer as disclosed in US Pat. No. 114135, or Slasher (Mitsui Mining Co., Ltd.), Cavitron (Eurotech Co., Ltd.), Microfluidizer (Mizuho Industry Co., Ltd.),
Continuous emulsifying and dispersing machines such as Gaulin homogenizer (Gaulin Co., Ltd.), Nanomizer (Nanomizer Co., Ltd.), and static mixer (Noritake Company).

When an organic solvent is used in the dispersion of spherical or substantially spherical colored resin particles obtained by emulsification, it is preferable to first remove the organic solvent by means such as distillation. Next, the aqueous dispersion is separated by filtration or the like, and the particles are dried to obtain toner particles. The colored resin particles obtained using an emulsifier or a dispersion stabilizer are preferably used after being sufficiently washed.

When resin particles are obtained using a self-water dispersible resin obtained by neutralizing an acidic group-containing polyester resin with a basic neutralizing agent as a binder resin, after removing the organic solvent, Reverse neutralization that returns the hydrophilic groups obtained by neutralization with a basic compound on the particle surface with an acidic neutralizing agent such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and oxalic acid to the original functional groups. It is preferable to employ a method of performing a treatment to further reduce the hydrophilicity of the particles themselves, and then removing water and filtering and drying.

The drying can be carried out by any known and commonly used method. For example, the drying may be carried out under normal pressure or reduced pressure at a temperature at which the toner particles do not fuse or agglomerate, or freeze drying. No. There is also a method of simultaneously separating and drying toner particles from an aqueous medium using a spray dryer or the like. In particular, a method of stirring and drying the powder under reduced pressure while heating at a temperature at which the toner particles do not fuse or agglomerate, or a flash jet dryer that instantaneously dries using a heated drying air flow (Seishin Enterprise) Is efficient and preferable.

If it is necessary to classify the formed toner particles to remove the coarse particles and fine particles in order to adjust the particle size distribution, after the drying is completed, a general air flow commercially available for toner or the like is used. It can be performed by a known and commonly used method using a type classifier. Also, at the stage where the toner particles are dispersed in the liquid medium, utilizing the difference in sedimentation depending on the particle size,
It may be carried out by a method of classifying a water slurry of toner particles using a centrifuge. The removal of the coarse particles can also be performed by filtering a water slurry of the toner particles using a filter, a wet vibration sieve, or the like. The particle size distribution of the toner of the present invention was measured by a Coulter Multisizer, and was 50% volume particle size / 50%.
A number particle size of about 1.25 or less is preferable because good images can be easily obtained.

The volume average particle diameter of the spherical powder toner of the present invention is preferably in the range of 1 to 13 μm from the viewpoint of the obtained image quality and the like, and about 3 to 10 μm is suitable for matching with the current machine. It is more preferable because it is easy. When the volume average particle diameter is small, not only the resolution and the gradation are improved, but also the effect that the thickness of the toner layer for forming the printed image is reduced and the toner consumption per page is reduced is particularly preferable. However, such characteristics of the spherical toner having a small particle diameter are remarkably exhibited when the particle diameter is as small as about 3 to 6 μm.

The powder toner particles obtained by drying can be used as a developer as they are, but an external additive such as inorganic oxide fine particles or organic polymer fine particles, which are well-known and used as a toner external additive, is applied to the toner particle surface. To improve properties such as fluidity and chargeability. Examples of such external additives include silica, titanium oxide, aluminum oxide, and vinyl (co) polymer. These external additives are preferably added in an amount of about 0.05 to 5% by weight based on the toner particles.

The toner of the present invention can be used as a one-component developer or a two-component developer mixed with a carrier for developing an electrostatic latent image by electrophotography. There is no particular limitation on the type of carrier, and known and commonly used iron powder, ferrite, magnetite, and the like, and carriers coated with a resin thereon are used.

Further, the toner of the present invention can be used as an electrode having a function of adjusting the toner passing amount and the like by using a non-magnetic one-component developing device having a developer carrying roll and a layer regulating member. Can be suitably used in a so-called toner jet printer, which is a method of forming an image by directly spraying the paper on the back electrode through a hole in a flexible printed circuit board having a peripheral portion. The toner of the present invention is excellent in fixability and color characteristics, and is spherical, so that the control of the toner flight in the toner jet method becomes easier as compared with the irregular toner.

[0065]

The present invention includes the following inventions and embodiments.

1. The binder resin is a polyester resin having an acid value of 1 to 30, and has a weight average molecular weight of 30,000 or more and a weight average molecular weight / number average molecular weight of 12 or more in gel permeation chromatography measurement of a tetrahydrofuran soluble portion of the binder resin. As described above, the area ratio of a molecular weight of 600,000 or more is 0.1.
A circular shape defined by an average circularity ((perimeter of a circle having the same area as the projected area of a particle) / (perimeter of a projected image of a particle)) in which an area ratio of 5% or more and a molecular weight of 10,000 or less is 20 to 80%. Spherical or substantially spherical powder toner having an average value of 0.97 or more.

2. 2. The powder toner according to the above item 1, wherein the binder resin comprises a blend resin of a crosslinked polyester resin and a linear polyester resin.

3. 3. The powder toner according to the above item 1 or 2, further comprising a wax.

4. The method for producing a powder toner according to the above 1 or 2, wherein a mixture containing a binder resin and a colorant as essential components is mixed with an aqueous medium and emulsified to thereby produce colorant-containing resin particles. And then separating the particles from a liquid medium and drying the particles.

5. The method according to the above item 4, wherein the mixture of the binder resin and the colorant is mixed with an aqueous medium to emulsify the mixture to form the colorant-containing resin particles, wherein the emulsification is performed in the presence of a basic neutralizing agent. Manufacturing method of powder toner.

[0071]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. In addition,
In the examples and comparative examples, parts are parts by weight, and water means deionized water.

(Polyester resin used) Resin A: acid value 8.5, Tg 61.7 ° C., viscosity 154 ° C. showing viscosity of 100,000 poise as measured by a flow tester, THF-soluble component weight average molecular weight 75,400, weight Average molecular weight / number average molecular weight 24.5, area ratio of molecular weight 600,000 or more 1.50
%, Crosslinked polyester resin. The THF insoluble content is 4.5
weight%.

Resin B: acid value 6.5, Tg 52.8 ° C., temperature 92.4 ° C. showing a viscosity of 100,000 poise as measured by a flow tester, THF-soluble weight-average molecular weight 5,70
0, weight average molecular weight / number average molecular weight 2.8, molecular weight 60
Linear polyester resin with an area ratio of 0% or more. THF
The insoluble content is 0% by weight.

In the present invention, the glass transition temperature Tg
Was measured by a second run method using a differential scanning calorimeter DSC-50 manufactured by Shimadzu Corporation at a heating rate of 10 ° C. per minute. The melt viscosity was measured using a flow tester CF manufactured by Shimadzu Corporation.
Using T-500, nozzle diameter 1.0mm ¢ × 1.0m
m, a load of 10 kg, and a heating rate of 6 ° C. per minute.

Example 1 52.2 parts of resin A, resin B
34.8 parts of Carnauba Wax No. 1 (Nippon Seiro Co., Ltd.) and 10 parts of carbon black pigment "Elftex 8" (Cabot) are kneaded with a twin-screw kneading extruder. The kneaded product was dissolved and dispersed in 150 parts of methyl ethyl ketone using a mill base. 750 parts of this mill base and 27.3 parts of 1N ammonia water were charged into a cylindrical container, and the liquid temperature was set to 13 ° C .; K. Robomix (Homomixer manufactured by Tokushu Kika Kogyo Co., Ltd., stirrer diameter 3
(0 mm) and 450 parts of water at a temperature of 13 ° C. are added all at once while stirring at 10,000 rpm. Liquid temperature 16-1
While maintaining the temperature at 8 ° C., stirring was continued for 9 minutes to complete granulation.

Next, MEK was removed by distillation under reduced pressure, and the residue was washed with filtered water. The wet cake was re-dispersed in water, and the pH was adjusted to about 3 by adding a 1N aqueous hydrochloric acid solution. The wet cake was freeze-dried and then classified by an airflow classifier to obtain toner particles having a volume average particle size of 5.8 μm and an average circularity of 0.985.

The toner particles were embedded in a resin, cut with a microtome, and stained with ruthenate tetroxide.
When observed with a transmission electron microscope, it was found that the pigment and the wax were included in the binder resin and dispersed almost uniformly in the particles.

2 parts of hydrophobic silica and 1 part of titanium oxide were externally added to 100 parts of the toner particles using a Henschel mixer to obtain Powder Toner 1. The glass transition temperature of this toner is 5
The temperature at which the viscosity at 4.8 ° C. was 100,000 poise as measured by a flow tester was 118 ° C. The acid value of the binder resin was 7.7, the weight-average molecular weight by GPC measurement of the THF-soluble component was 42,700, the weight-average molecular weight / number-average molecular weight was 15.7, and the area of the resin component having a molecular weight of 600,000 or more. The ratio is 1.1%, and the area ratio of the resin component having a molecular weight of 10,000 or less is 62.
2%.

(Example 2) A masterbatch is prepared by kneading 50 parts of a phthalocyanine pigment "Ket Blue 123" (Dainippon Ink and Chemicals) and 50 parts of resin B with two rolls. 8 parts of this masterbatch, 55.75 of resin A
Part, 33.25 parts of resin B, 3 of carnauba wax No. 1
Parts were kneaded with a twin-screw kneading extruder, and then the kneaded product was dissolved and dispersed in 150 parts of methyl ethyl ketone using Despa to form a mill base. 750 parts of this mill base and 25.8 parts of 1N ammonia water were charged into a cylindrical container, and the liquid temperature was reduced to 1 part.
2 ° C., T.V. K. 10000r using Robomix (Homomixer manufactured by Tokushu Kika Kogyo Co., Ltd., diameter of agitating section 30mm)
While stirring at pm, 487 parts of water at a temperature of 6 ° C. are added at once. Agitation was continued for 37 minutes while maintaining the liquid temperature at 16 to 18 ° C. to complete granulation.

Next, MEK was removed by distillation under reduced pressure, and the residue was washed with filtered water. The wet cake was re-dispersed in water, and the pH was adjusted to about 3 by adding a 1N aqueous hydrochloric acid solution. The wet cake was freeze-dried and classified by an airflow classifier to obtain toner particles having a volume average particle size of 5.7 μm and an average circularity of 0.983.

The toner particles were embedded in a resin, cut with a microtome, and stained with ruthenate tetroxide.
When observed with a transmission electron microscope, it was found that the pigment and the wax were included in the binder resin and dispersed almost uniformly in the particles.

Powder toner 2 was obtained by externally adding 2 parts of hydrophobic silica and 1 part of titanium oxide to 100 parts of the toner particles using a Henschel mixer. The glass transition temperature of this toner is 5
The temperature at which the viscosity was 100,000 poise as measured by a flow tester at 4.8 ° C. was 117 ° C. The acid value of the binder resin was 7.7, the weight-average molecular weight by GPC measurement of the THF-soluble component was 42,700, the weight-average molecular weight / number-average molecular weight was 15.7, and the area of the resin component having a molecular weight of 600,000 or more. Ratio is 1.1%, and the area ratio of the resin component having a molecular weight of 10,000 or less is 6
2.2%.

(Examples 3 and 4) Instead of the phthalocyanine pigment, a quinacridone pigment "Toner Magenta E-02" was used.
(Hoechst Industry) or powder toner 3 and powder toner 4 were respectively obtained in the same manner as in Example 2 except that disazo pigment “Ket Yellow 403” (Dainippon Ink and Chemicals) was used.

In each case, the pigment and the wax were included by TEM observation, and the volume average particle diameter was 5.8 μm and the average circularity was 0.983. The molecular weight and molecular weight distribution of the THF-soluble component by GPC measurement were the same as in Example 2.

Comparative Example 1 A pigment was obtained in the same manner as in Example 1 except that the blend ratio of the resin A and the resin B was changed to 4: 6, the volume average particle diameter was 5.8 μm, the average circularity was 0.985, and the pigment was And a powder toner 5 containing wax and a binder resin.

The glass transition temperature of the toner is 53.2 ° C.
The temperature at which a viscosity of 100,000 poise was measured by a flow tester was 113 ° C. The acid value of the binder resin is 7.
3. The weight average molecular weight by GPC measurement of the THF-soluble component was 31,000, and the weight average molecular weight / number average molecular weight was 11.
8. The area ratio of the resin component having a molecular weight of 600,000 or more is 0.35.
%, And the area ratio of the resin component having a molecular weight of 10,000 or less was 61.6%.

Comparative Examples 2 and 3 52.2 parts of resin A, 34.8 parts of resin B, 3 parts of Carnauba wax No. 1, and 10 parts of carbon black pigment "Elftex 8" (Cabot Corporation) The mixture kneaded with a twin-screw kneading extruder was pulverized and classified to obtain a powder toner 6 having a volume average particle size of 5.8 μm and a powder toner 7 having a volume average particle size of 7.8.
Each of them had an average circularity of 0.950, and some of the pigment and wax were exposed on the surface of the toner particles.

The glass transition temperature of the toner is 54.8 ° C.
The temperature at which a viscosity of 100,000 poise was measured by a flow tester was 118 ° C. The acid value of the binder resin is 7.
7, the weight-average molecular weight of the THF-soluble component by GPC measurement was 42,700, and the weight-average molecular weight / number-average molecular weight was 15.
7, the area ratio of the resin component having a molecular weight of 600,000 or more is 1.1%,
The area ratio of the resin component having a molecular weight of 10,000 or less was 64.0%.

(Image Deposition Test) With respect to the powder toners 1 to 7 of the examples and the comparative examples, images were extracted using a commercially available non-magnetic one-component developing system printer (Epson LP-1700), and Table 1 shows the evaluations of image quality, gradation, and image density.

Further, with respect to the powder toners 1 to 4 of the examples, a silicon-coated ferrite carrier (particle size: 80 μm) was used.
m) and a toner concentration of 3% by weight, and a two-component developing type copying machine (Ricoh Imagio MF-530) was used to perform an image output test. As a result, good images were obtained.

(Fixability Test) Each printing paper made from the powder toners 1 to 7 of the examples and comparative examples is fixed at a speed of 90 mm / sec through a heat roll (oil-less type) of Ricoh Imagio DA-250. Then, a cellophane tape is attached to the image after fixing, and the surface temperature range of the heat roll when the ID (image density) after peeling is 90% or more of the original ID and no occurrence of offset is observed is defined as “ Fixing temperature range
And the measurement results are shown in Table 1.

In the heat blocking test at 50 ° C. for 3 days, no agglomeration was observed in all of the toners of Examples and Comparative Examples.

Although the fixing temperature range of the toner 5 is narrow and it is difficult to put it to practical use, the other toners show excellent low-temperature fixability and fixing temperature range with a heat roller not coated with an anti-offset liquid. . In addition, the spherical or substantially spherical toner of the present invention using a polyester resin as a binder resin by the emulsification dispersion method is particularly excellent in comparison with the toner 6 and the toner 7 as compared with the irregular toner by the pulverization method. A quality image is obtained.

[Table 1] Table-1

The resolution and gradation were evaluated using test patterns. The evaluation was made by comparing the resolution and gradation of the toner 7 closest to the powder toner generally used in the test printer with the shape and the particle size in terms of the shape and the particle size as standard.
○ indicates slightly better than standard, and ◎ indicates even better. Fog is determined visually. ○ indicates good, and × indicates fog size. Image density was measured using a Macbeth densitometer. Normally, an image density of 1.3 or more is desired.

[0095]

According to the present invention, the spherical to substantially spherical toner of the present invention obtained by the emulsification dispersion method using a polyester resin having a specific range of molecular weight / molecular weight distribution as a binder resin is excellently fixed by a heat roller to which no anti-offset liquid is applied. And low-temperature fixability, and an image of excellent quality can be obtained. Also,
Such a powder toner forms a colorant-containing resin particle by mixing and emulsifying a mixture containing a binder resin and a colorant as essential components, and then separating the particle from the liquid medium. Then, it can be suitably manufactured by drying.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takayuki Ito 2-6-16-202 Higashi-Kojiya, Ota-ku, Tokyo (72) Inventor Toshiro Furukawahara 5085-1 Iwatsuki, Iwatsuki-shi, Saitama F-term (reference) 2H005 AA01 AA06 AA15 AB03 CA08 CA14 CA17 DA06 DA10 EA06 EA07 EA10 FB01

Claims (5)

[Claims] 1. A binder resin comprising a polyester resin having an acid value of 1 to 30, having a weight average molecular weight of 30,000 or more in gel permeation chromatography measurement of a tetrahydrofuran soluble portion of the binder resin, and a weight average molecular weight / Number average molecular weight 12 or more, molecular weight 600,000 or more area ratio 0.5%
As described above, the area ratio of the molecular weight of 10,000 or less is 20 to 80%.
Average circularity ((perimeter of a circle having the same area as the projected area of the particle) /
Spherical or substantially spherical powder toner having an average value of circularity defined by (perimeter of particle projected image) of 0.97 or more. 2. The powder toner according to claim 1, wherein the binder resin comprises a blend resin of a crosslinked polyester resin and a linear polyester resin. 3. The powder toner according to claim 1, further comprising a wax. 4. A method for producing a powder toner according to claim 1, wherein a mixture containing a binder resin and a colorant as essential components is mixed with an aqueous medium and emulsified. Forming a colorant-containing resin particle, and then separating the particle from a liquid medium and drying. 5. The method according to claim 1, wherein a mixture of the binder resin and the colorant is mixed with an aqueous medium and emulsified to form a colorant-containing resin particle, wherein the emulsification is carried out in the presence of a basic neutralizing agent. The method for producing a powder toner according to claim 4.