JPH0486744A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To form an image having a sharp and good tone by using a polyester resin as the main component of a binder resin and specifying its glass transition point and softening point and average particle diameter. CONSTITUTION:The polyester resin is used as the main component and its glass transition point and softening point are regulated to >= 40 deg.C and 80 - 150 deg.C, respectively, and the particles having a particle diameter of 0.5D - 2D amount to >= 80 number % of the total particles, where D is an average particle diameter and it is 3 - 6 mum. This polyester resin comprises mainly discarboxylic components, such as terephthalic acid components, and glycol components, thus permitting development performance of not only single color but also a color mixed with another color to be improved in reproduction performance of an intermediate color to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to toner. More specifically, the present invention relates to a toner used as a developer in electrophotographic copying machines, laser printers, and the like.

(Prior art) In general, electrophotography involves photoconductive materials (often processed into a drum shape) made of inorganic materials such as selenium, amorphous silicon, and zinc oxide, or organic materials such as diazo compounds and dyes. (: photosensitive drum) is first charged in a negative manner,
Next, an electrostatic latent image is formed by irradiating image-modulated light, and developed by attaching powder to the electrostatic latent image using electrostatic force. After transferring the powder to the surface, it is fixed by applying pressure, heating, or other methods. Electrophotography is currently available in copying machines,
Widely used in laser printers, etc.

In electrophotography, a powder that develops an electrostatic latent image on a photosensitive drum and is ultimately transferred to a base material such as paper or film to form an image is called a toner. These toners usually have carrier particles (carrier) such as iron powder or ferrite.
It is used as a so-called developer.

Conventionally, toners used in electrophotographic developers include:
Particles have been used that are produced by a so-called pulverization method, in which a coloring agent, a charge control agent, a fluidity modifier, a pulverization aid, etc. are added to a thermoplastic resin, the mixture is kneaded, and then pulverized and further classified. Alternatively, in recent years, some studies have been conducted on toners using emulsion polymerization, suspension polymerization, seed polymerization, and the like.

These toners are required to have various physical or chemical properties. In recent years, in order to improve the quality of copied images,
There is a trend for toners to have smaller particle sizes and sharper particle size distributions.

(Problems to be Solved by the Invention) In order to improve the quality of copied images, manufacturing problems cannot be left out of discussion regarding toners with smaller particle sizes, which have recently been strongly demanded. In other words, it is difficult to industrially obtain particles having an average particle diameter of about 10 μm or less using the pulverization method that has been used as a method for producing toner in many cases. If you are simply crushing the resin itself, the current crusher can handle 10μ
It is not very difficult to obtain particles smaller than m.

However, since not all of the pulverized particles have the desired particle size, a classification operation is naturally required. This means that the retention rate will drop significantly.

Furthermore, when producing toner with a fine particle size using the pulverization method, coloring agents, charge control agents, fluidity modifiers, pulverization aids, etc. added to the thermoplastic resin, which is the main component, are required in advance. It must be ground to a size smaller than the particle size, which inevitably increases production costs. These reasons make it difficult to industrially produce toner having a fine particle size by the pulverization method.

The shape of the toner obtained by the pulverization method is naturally amorphous and only exhibits a broad particle size distribution.

Now, as mentioned above, the electrophotographic method involves repeating electrostatic transfer. Therefore, management of the amount of charge on the toner is an important technical point. The amount of charge on the toner due to frictional charging is influenced by many factors, but basically depends on the surface area. Since the surface area depends on the particle size of the toner, the distribution of the amount of charge basically depends on the particle size distribution of the toner.

If the ratio of particles having a diameter of 0.5D or less, where D is the average particle diameter, is large, the fluidity of the toner may be impaired. Obstruction of fluidity affects the state of triboelectric charging, so that the distribution of toner charge amount becomes wider. The distribution of toner charge amount is a cause of "fogging" as well as variations in the density of a copied image. Furthermore, the toner tends to scatter during cleaning of the photosensitive drum, resulting in significant contamination of the inside of the apparatus.

If the proportion of particles with a radius exceeding 2D increases when the average particle diameter is D, an unnecessary gap will be created between the photosensitive drum and paper during transfer from the photosensitive drum to paper, causing fine particles to move outward. It will generate a lot of "dust" that scatters.

In any case, the broadening of the particle size distribution of the toner adversely affects the resolution of the copied image and significantly impairs the sharpness of the image.

In recent years, research on toners using emulsion polymerization, suspension polymerization, seed polymerization, etc. has been conducted in some areas.
This method is intended to address the problems of the pulverization method described above.

Particles obtained by the polymerization method have excellent fluidity because they are spherical in shape, and can therefore be expected to have uniform triboelectrification.Furthermore, by appropriately controlling polymerization, it is possible to control thermal melting characteristics, etc. It can be expected to have similar characteristics.

In the emulsion polymerization method, polymerization is carried out in micelles of polymerizable monomers stabilized with a surfactant in water to obtain fine powder particles.

In the emulsion polymerization method, particles having a sharp particle size distribution can be obtained. However, since the particle size is determined by the size of micelles that can stably exist, the particle size is limited to a range of about 0.01 to 0.5 μm, and particles with a particle size of about 1 μm or more are created. That is difficult.

Since the particle size required for toner is limited to approximately several μm to several μm, particles obtained by emulsion polymerization cannot be used as they are in toner for electrophotography. Furthermore, if a surfactant essential for stabilizing micelles remains on the particle surface, it may affect the fluidity or charging characteristics of the particles.

The suspension polymerization method is a method in which particles are obtained by polymerizing polymerizable monomers in a suspension system obtained by stirring water and polymerizable monomers. In suspension polymerization, polymerization in a stable system is not easy, and it is technically difficult to obtain fine polymer particles with a uniform particle size distribution through polymerization.

The reason for this is that coalescence of particles occurs during granulation. In order to prevent coalescence of particles and stabilize polymerization, for example, in suspension polymerization, when polymerizable monomers are polymerized in an aqueous dispersion system, coalescence of particles is prevented as the polymerization progresses. Use suspension stabilizers to prevent this. Suspension stabilizers generally include sparingly soluble inorganic compounds, such as sparingly soluble salts such as barium sulfate, calcium sulfate, magnesium carbonate, barium carbonate, calcium carbonate, and calcium phosphate, and metals such as silica, calcia, magnesia, and titanium oxide. Minerals such as oxides, diatomaceous earth, talc, clay, and kaolin, and mixtures thereof, and water-soluble mixtures such as polyvinyl alcohol, gelatin, and starch are used. These suspension stabilizers are known to have a negative effect on the charging characteristics of particles if they remain on the particle surface, so cleaning etc. are essential after obtaining polymerized particles, but it is not possible to completely remove them. is extremely difficult. In reality, even when these suspension stabilizers are used, the particle size range of particles obtained by suspension polymerization is approximately several tens of μm or more, and the particle size distribution is also broad, so electrophotography It is difficult to obtain a particle size in the range of several micrometers to several micrometers, which is required for toners for commercial use.

The seed polymerization method is a polymerization method proposed to solve these problems. In the seed polymerization method, for example, particles obtained by other methods such as emulsion polymerization are used as seed particles, the seed particles are swollen with a solvent and a polymerizable monomer, and polymerization is performed within the swollen seed particles. This is a method of growing seed particles to a large size. In the seed polymerization method, particles with a uniform particle size distribution can be obtained by selecting appropriate seed particles. Further, the particle size of the particles can be controlled by the swelling ratio of the seed particles and the polymerizable monomer.

However, the swelling rate of seed particles cannot be increased unnecessarily. For example, increasing the particle size by ten times corresponds to increasing the volume by a thousand times. When the seed particles are swollen approximately 1,000 times with the polymerizable monomer, the seed particles are no longer able to maintain their particle shape.
In some cases, it will collapse. That is, the swelling ratio cannot be extremely increased, and there is a natural limit to the particle size range that can be grown to a certain degree, which is about 2 to 3 times the size at most. If it is desired to grow larger particles, it is necessary to repeat seed polymerization.

In seed polymerization, it is technically possible to obtain particles with a sharp particle size distribution in the particle size range of several μm to more than ten μm. However, it is not easy to find suitable particles as seed particles, and the manufacturing cost is enormous due to the complexity of the process, so it is difficult to supply toner for electrophotography at an industrial level. There is no way to do that.

In other words, the number of micrometers required for electrophotographic toner is
It is extremely difficult to industrially produce particles with a sharp particle size distribution in the particle size range of ~10-odd micrometers at a low cost using conventional polymerization methods.

Further, resin particles obtained by conventional polymerization methods are limited to so-called vinyl resin particles, typified by styrene/acrylic resins and the like.

In addition, to the resin particles obtained by these polymerization methods, charge control agents, colorants, anti-offset agents, etc., which are used to impart many physical properties essential to electrophotographic toners, are used.
It is not easy to add fluidity improvers and the like. That is, even with resin particles obtained by conventional polymerization methods, many of the problems required of toners have not yet been solved.

As mentioned above, conventional toners have moisture resistance, that is, humidity dependence such as charging characteristics, flow characteristics, and insulation, as well as fixing properties, sharp melt properties, offset resistance, particle size distribution, transparency, and color reproduction. This product had many problems in terms of performance, manufacturing cost, etc.

In view of this situation, the inventors of the present invention have conducted extensive research in order to obtain a toner that comprehensively satisfies many of these required characteristics and can be produced industrially, and as a result, they have arrived at the following invention.

(Means for Solving the Problem) That is, the present invention has a polyester resin as a main component, and the glass transition point of the polyester resin is 40°C or higher,
The softening point is in the range of 80 to 150°C, and when the average particle size is D, particles with a diameter in the range of 0.5D to 2D account for 80% or more of the total on a number average, and This is an electrophotographic toner characterized by an average particle size of 3 to 6 μm.

In the present invention, the average particle size is 3 to 6 μm, and when the average particle size is D, particles with a diameter in the range of 0.5D to 2D account for more than 80% of the total number average. As a method for obtaining polyester resin particles having a sharp particle size distribution, for example, in an aqueous dispersion mainly composed of an ionic group-containing polyester resin, a vinyl monomer containing a counterion group of the resin is added at an equivalent ratio of 0.8. An example of a method for manufacturing by polymerizing 2.0 from

Here, the polyester resin mainly consists of a dicarboxylic acid resin and a glycol component. Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and 1,5-naphthalic acid, and aromatic oxycarboxylic acids such as p-oxybenzoic acid and p-(hydroxyethoxy)benzoic acid. acids, aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, fumaric acid, maleic acid,
Examples include unsaturated aliphatic acids such as itaconic acid, hexahydrophthalic acid, and tetrahydrophthalic acid, and alicyclic dicarboxylic acids.

If necessary, a small amount of tri- and tetracarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid may be included.

Glycol components include, for example, ethylene glycol, propylene gellicol, 1,3-propanediol, 1,
4-butanediol, 1,5-bentanediol, 1.
6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2.2.
4-) Dimethyl-1,3-bentanediol, 1,4-
Cyclohexane dimetatool, spiroglycol, 1°4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, diol such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene oxide adduct of bisphenol A, propylene oxide adduct,
Examples include ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A.

If necessary, a small amount of triol and tetraol such as trimethylolethane, trimethylolpropane, glycerin, and pentanylthritol may be included.

Other examples of polyester polyols include lactone-based polyester polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone.

The ionic groups contained in the polyester resin include anionic groups such as carboxyl groups, sulfonic acid groups, sulfuric acid groups, phosphoric acid groups, or salts thereof, or cationic groups such as primary to tertiary amine groups. and preferably a sulfonic acid metal base.

Examples of aromatic dicarboxylic acids containing sulfonic acid metal bases that can be copolymerized with polyester include sulfoterephthalic acid, 5-
Examples include metal salts of sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7dicarboxylic acid, and 5[4-sulfophenoxyfisophthalic acid. As a metal salt, LtlNa, , 1Mgt Ca1C
Examples include salts such as u1Fe. Particularly preferable ones are 5-
Sodium sulfoisophthalate.

The amount of the aromatic dicarboxylic acid containing a sulfonic acid metal group is not limited as long as the aqueous dispersion can be obtained.
A range of approximately 20 to 500 equivalents/1,000,000 g is appropriate.

In the present invention, the polyester resins can be used alone or in combination of two or more if necessary.

Further, it can be mixed with amino resins, epoxy resin isocyanate compounds, etc. in a molten state or a solution state, and furthermore, it can be partially reacted with these compounds. The obtained partial reaction product can also be used as a raw material for an aqueous dispersion.

The aqueous dispersion containing the ionic group-containing polyester resin of the present invention as a main component can be produced by any known method. That is, a polyester resin and a water-soluble organic compound are mixed in advance at 50 to 200°C and water is added to this, or a mixture of a polyester resin and a water-soluble organic compound is added to water and stirred at 40 to 120°C. Manufactured by Alternatively, by adding polyester resin to a mixed solution of water and a water-soluble organic compound,
It can also be produced by stirring and dispersing at 00°C.

In the present invention, the "vinyl monomer containing a counterionic group" refers to an ionic group opposite to the ionic group contained in the polyester resin (a counterion when the ionic group contained in the polyester resin is an anionic group). A cationic group means a vinyl monomer having a cationic group, and when the ionic group contained in the polyester resin is a cationic group, a counterionic group is an anionic group. Such ionic groups are essential for forming a stable aqueous dispersion of polyester resin.

The amount of counterionic groups in the polymer obtained by polymerizing vinyl polymerizable monomers is 0.8 to 2 in equivalent ratio to the amount of ionic groups in the polyester resin.
．． 0, preferably in the range of 0.85 to 1.5. If the lower limit of this range is not reached, coalescence and growth of the fine particles will not occur (and even if the upper limit is exceeded, not only will it not contribute to the growth of the fine particles, but it may also cause problems such as a decrease in the water resistance of the resin particles. .

As the cationic group-containing vinyl monomer, for example, 2
-Aminoethyl (meth)acrylate, 2-N,N-dimethylamineethyl (meth)acrylate, 2-N,N
-diethylaminoethyl (meth)acrylate, 2-N
, N-dipropylamino (meth)acrylate, 2-N
, t-butylaminoethyl (meth)acrylate), 2-
(4-morpholino)-ethyl (meth)acrylate,
Examples include 2-vinylpyridine, 4-vinylpyridine, and aminostyrene.

In addition, examples of anionic group-containing vinyl monomers include (meth)acrylic acid, itaconic acid, furotic acid, maleic acid,
Monomers containing carboxyl groups or their salts such as fumaric acid, styrenesulfonic acid, vinyltoluenesulfonic acid, vinylethylbenzenesulfonic acid, impropenylbenzenesulfonic acid, 2-chlorostyrenesulfonic acid, 2-methyl-4-chlorostyrene Sulfonic acid groups, such as sulfonic acid, vinyloxybenzenesulfonic acid, vinylsulfonic acid, (meth)allylsulfonic acid, sulfoethyl or sulfopropyl ester of (meth)acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, or Monomers containing the salts Phosphoric acids such as azidophosphoxyethyl (meth)acrylate, azidophosphoxypropyl (meth)acrylate 3-chloro-2-azidophosphoxypropyl methacrylate, bis(meth)acryloxyethyl phosphate, vinyl phosphate, etc. Examples include monomers containing groups or salts thereof.

In order to achieve the object of the present invention, a combination of a cationic group-containing vinyl monomer and an anionic group-containing vinyl monomer is more desirable. In addition, there is no problem in appropriately using known nonionic monomers.

There are no particular restrictions on the polymerization initiator used when polymerizing vinyl monomers, and examples include organic peroxides such as benzoyl peroxide and acetyl peroxide, 2,2"-azobisisobutyronitrile, 2,2'- Azo compounds such as azobis(2,4-dimethylvaleronitrile), persulfates, hydrogen peroxide,
Inorganic peroxides such as permanganates, water-soluble redox systems of the inorganic peroxides and reducing agents such as sulfites, bisulfites, metasulfites, hydrosulfites, thiosulfates, iron salts, oxalic acid, etc. Examples include initiators, but water-soluble redox initiators are preferred from safety and industrial viewpoints. The amount of polymerization initiator used is approximately 0.1 to 0.1 to vinyl monomer.
It is within the range of 3% by weight.

Although it is difficult to define the polymerization temperature unambiguously, it is possible to
In order to coalesce and grow into a spherical shape as the vinyl monomer polymerizes, it is desirable to adopt a temperature condition equal to or higher than the glass transition point (Tg) of the polyester resin; conditions below this temperature tend to produce irregularly shaped particles. In addition, by using a solvent or a plasticizer for the polyester resin, the apparent glass transition point (or minimum film forming temperature) of the polyester resin can be lowered, and polymerization can be carried out at a temperature higher than the boiling temperature. The types of solvents and plasticizers are not limited, and are appropriately selected from known ones depending on the type of polyester resin, as long as they do not inhibit polymerization.

Other polymerization conditions are carried out according to conventional methods, but the method of charging the vinyl monomer in advance into an aqueous dispersion of polyester resin fine particles, and then dropping the polymerization initiator dropwise causes rapid coalescence and aggregation of the polyester resin fine particles. This is preferable because there are no problems.

The obtained aqueous dispersion of polyester resin particles is filtered,
It is extracted as a dry powder using conventional methods such as freeze drying and spray drying.

Thus, the electrophotographic toner of the present invention has an average particle size of 3 to 6 μm, and where the average particle size is D, the particle size falls within the range of 0.5D to 2D. It is possible to industrially produce polyester resin particles having a sharp distribution in which the number average is 80% or more of the total.

The glass transition point of the polyester resin in the present invention is 40
℃ or higher. If the glass transition point is lower than this,
It has a tendency to aggregate during handling or storage, which may cause problems with storage stability.

The softening point of the polyester resin in the present invention is 80 to 15
It is in the range of 0°C. Toners in which the softening temperature of the resin is kept lower than this tend to aggregate during handling or storage, and fluidity may significantly change, particularly during storage during storage. If the softening point is higher than this, fixing performance will be impaired. Furthermore, since it is necessary to heat the fixing roll to a high temperature, the material of the fixing roll and the material of the base material on which the blanks and copies are made are limited.

The method for coloring the electrophotographic toner in the present invention is not particularly limited, and any known existing colorant such as a pigment, dye, or carbon black may be used. In particular, from the viewpoint of spectral transmission characteristics, it is preferable to use a dye. As the dye used for coloring, it is preferable to use a disperse dye, a basic dye, a cationic dye, a dispersed cationic dye, or the like. When obtaining a black toner, there is no problem in using carbon black or the like.

As carbon black, thermal black, acetylene black, channel black, furnace black, lamp black, etc. can be used. As the pigment, azo lake pigments, rhodamine pigments, quinacridone pigments, etc. can be used. These dyes, pigments, carbon black, etc. may be used alone,
Alternatively, they may be used together if necessary.

In the electrophotographic toner of the present invention, a charge control agent may be used to provide stable charge. Examples of charge control agents that positively charge the toner through friction with carrier particles include titanates such as Ca1Ba, carbonates, alkoxylated amines,
Polyamide resin such as nylon, phthalocyanine blue
Pigments with positive zeta potential such as quinacridone red and azo metal complex green, azine compounds, stearic acid-modified azine compounds, oleic acid-modified azine compounds, azine pigments such as nigrosine, quaternary ammonium salt compounds etc.

Examples of charge control agents that impart a negative charge to the toner through friction with carrier particles include pigments with a negative zeta potential such as carbon black, halogenated phthalocyanine green, flavanstone yellow, and perylene red, copper, and zinc. , lead, iron, and other metal-containing azo compounds.

In the toner of the present invention, a fluidity modifier such as fine alumina particles or fine silica particles may be added.

The amount added is not particularly limited, but from the viewpoint of imparting appropriate fluidity, it is preferably 0.00 to the toner.
The amount is about 0.01 to 5% by weight, more preferably about 0.1 to 2% by weight.

In the case of a toner-based developer that is used without being mixed with carrier particles (=carrier), the toner needs to be magnetic. In such cases, iron, cobalt, nickel, or alloys based on these, may be used as necessary.
Alternatively, oxides such as ferrite may be included.

The method of treating particles with the colorant, charge control agent, fluidity modifier, etc. described above is not particularly limited, and any known existing treatment method can be used. These may, for example, be dispersed in the particles, adsorbed onto the particles, coated on the particles, or implanted into the particle surfaces by, for example, a dry process such as mechanofusion.

The polyester resin used in the toner of the present invention exhibits good fixing properties because it does not cause fusion or aggregation at room temperature, and its viscosity quickly decreases during fixing.

The polyester resin used in the toner of the present invention has excellent color development in dyeing and also has excellent stability against dyes, so it exhibits good light resistance.

Since the toner in the present invention has excellent transparency, it not only produces a single color, but also has good color mixing properties when layered with other colors, so it has excellent reproducibility of intermediate colors. Furthermore, when an image is formed on a transparent film used in an overhead projector or the like, the image projected onto a screen also exhibits good color tone.

(Example) The present invention will be explained in more detail by referring to Examples below, but the present invention is not limited to these in any way. In addition, the physical properties of the resin in Examples and Comparative Examples were measured by the following method.

・Melting point, glass transition point A heating rate of 1 was measured using a differential scanning calorimeter (manufactured by Shimadzu Corporation).
Measured at 0″C/min.

・Softening point Measured according to JIS K2351.

・Number average molecular weight (vapor pressure method) It was measured using a molecular weight measuring device (newly manufactured by Hitachi Seisakusho).

・Electrical charge amount Measured using an E-Spart Analyzer (manufactured by Micron for wire use), and converted to the amount of charge per surface area, assuming that the particles were true spheres.

Example 1 In an autoclave equipped with a thermometer and a stirrer, 94 parts by weight of dimethyl terephthalate, 95 parts by weight of dimethyl isophthalate, 89 parts by weight of ethylene glycol,
Add 1 part of neopentyl glycol BOMf and 0.1 part by weight of tetrabutoxy titanate to 120~
The transesterification reaction was carried out by heating at 230° C. for 120 minutes. Next, 6.7 parts by weight of 5-sodium sulfoisophthalic acid was added, and the reaction was continued for 60 minutes at 220 to 230°C, and further,
After raising the temperature to 250° C., the reaction was continued for 60 minutes at a system pressure of 1 to 10 mmHg, resulting in a copolymerized polyester resin (A1).

The molecular weight of the obtained copolymerized polyester resin (A1) is 2
700. Sulfonic acid metal base is 118 equivalents/10,000
It was 00g. The amount of sulfonic acid metal base was determined by measuring 1 degree of sulfur in the copolymerized polyester resin. In addition, as a result of NMR analysis, the composition of the copolymerized polyester resin (A1) was found to be as follows: 48.5M0L% of terephthalic acid, 49.0M0L% of isophthalic acid, 2.5M0L% of 5-sodium sulfoisophthalic acid, and 2.5M0L% of alcohol component as acid components. Ethylene glycol was 61.0M0L%, and neopentyl glycol was 39.0M0L%.

After dissolving 34 parts by weight of the obtained copolymerized polyester resin (AI) and 10 parts by weight of butyl cellosolve at 110°C in a four-necked 1-liter separable flask equipped with a thermometer, condenser, and stirring blade, Aqueous dispersion of copolyester by adding 56 parts by weight of water at 80°C (B1)
I got it.

In a four-necked 1-liter separable flask equipped with a thermometer, a condenser, and a stirring blade, 834 parts by weight of copolyester aqueous dispersion (Bl), 35 parts by weight of deionized water,
Then, 5.6 parts by weight of dimethylamine ethyl methacrylate was added, and the temperature was raised to 70°C. Next, 100 parts by weight of an aqueous solution containing 0.2 parts of ammonium persulfate was added dropwise over 30 minutes, and the reaction was continued at 70°C for an additional 20 minutes. As a result, the copolymer with a submicron-order particle size that existed in the copolymerized polyester aqueous dispersion grew into particles with an average particle size of 5.2 μm and a particle size in the range of 0.5D to 2D, where 1 diameter is D. Polyester particles (C1) having a 92% occupancy (number) of particles having the following properties were obtained.

Water was added to the obtained polyester particles (C1) for 20
A polyester particle aqueous dispersion (Dl) of % by weight was obtained.

Sumitomo Chemical Disperse Dye Sumikaronsho Yellow 5E-5G (
C, 1, Disperse Yellow 5) 10 parts by weight of water 1
00 parts by weight of PoIJ ester particle dispersion (D
I) was added to 500 parts by weight, heated to 50° C. with stirring, and held for 60 minutes.

Thereafter, it was cooled, filtered, washed, and dried in vacuum to obtain a yellow toner (EIY).

Similarly, Sumitomo Chemical disperse dye Sumikalon Red 5E-3
A magenta toner (ELM) and a cyan toner (EIC) were obtained from a polyester particle dispersion (Dl) using GL1 Sumikalon Brilliant Blue 5-BL.

1 part by weight of each of the obtained colored toners was mixed with 99 parts by weight of a carrier (spherical reduced iron powder with an average particle size of 80 μm),
A component-based electrophotographic developer was obtained.

The charge amount of the toner after mixing with the carrier was (EIY) -125 uc/g (ELM) -116 uc/g (EIC) -118 μc/g. Using these developers, 5,000 copies were continuously made on paper using an electrophotographic color copying machine using amorphous silicon as a photoreceptor.

The resulting copy was free from fog and fading, and showed a clear and good image.

Using this developer, copies were similarly made on a transparent film for an overhead projector. The obtained copy had excellent spectral transmission characteristics, and the image projected onto the screen by the Overherad projector showed a clear color tone without turbidity. The resolution when using this developer is approximately 16
books/mm. Further, no particular problems were observed in the humidity dependence of charging properties, flow properties, insulation properties, etc., as well as fixing properties, sharp melt properties, anti-offset properties, etc.

Example 2 Dimethyl terephthalate 94 parts by weight, dimethyl isophthalate 95 parts by weight, ethylene glycol 80 parts by weight
A copolymerized polyester resin (A
2) was obtained. Obtained copolymerized polyester resin (A2)
The molecular weight of the sulfonic acid metal base is 2800°, 24 equivalents/
It was 1,000,000g. In addition, as a result of NMR analysis, the composition of the copolymerized polyester resin (A2) is as follows: 49.5M0L% of terephthalic acid, 50.0M0L% of isophthalic acid, 0.5M0L% of 5-sodium sulfoisophthalic acid, and 0.5M0L% of alcohol component as acid components. Ethylene glycol was 53.0M0L%, and neopentyl glycol was 47.0M0L%.

Next, an aqueous dispersion (B2) of copolymerized polyester was obtained in the same manner as in Example 1, and polyester particles (C2) were further obtained in the same manner. The obtained polyester particles (C
The average particle size of 2) was 4.2 μm, and the occupancy (number) of particles having a particle size in the range of 0.5D to 2D was 88%.

The obtained polyester particles (C2) were made into a polyester particle aqueous dispersion (B2) in the same manner as in Example 1, and further dyed in the same manner as in Example 1 to form a colored toner (E2).
Y) (E2R) (E2B) was obtained.

5 parts by weight of each of the obtained colored toners were mixed with 95 parts by weight of a carrier (spherical reduced iron powder with an average particle size of 80 μm),
A component-based electrophotographic developer was obtained.

The charge amount of the toner after mixing with the carrier was (E2Y) -135 μC/g (E2M) -122 μC/g (E2C) -127 μC/g. Using these developers, 5,000 copies were continuously made on paper using an electrophotographic color copying machine using amorphous silicon as a photoreceptor in the same manner as in Example 1. The resulting copy was free from fog and fading, and showed a clear and good image.

Using this developer, copies were similarly made on a transparent film for an overhead projector. The obtained copy had excellent spectral transmission characteristics, and the image projected onto the screen by the Overherad projector showed a clear color tone without turbidity. The resolution was about 20 lines/mm. In addition, charging characteristics, flow characteristics, humidity dependence such as insulation, fixing properties,
/ No particular problems were observed in yarn melting properties, offset resistance, etc.

Comparative Example 1 Copolymerized polyester resin (Al
) and 10 parts by weight of an azo yellow pigment, a rhodamine red pigment, and a phthalocyanine blue pigment, respectively, were premixed in a ball mill, melted and mixed in a roll mill, and ground and separated in a fine grinder. The average particle diameter of the ball is 5.8μ
m colored toners (D3Y) (D3M) (D3C) were obtained. In the obtained toner, particles having a particle size of 0.5D or less accounted for 20% on average, and particles having a particle size of 2D or more accounted for 15% on average.

5 parts by weight of each of the obtained colored toners were mixed with 95 parts by weight of carrier (spherical reduced iron powder with an average particle size of 80 μm) in the same manner as in the example to obtain a two-component electrophotographic developer. The charge amount of the toner after mixing with the carrier was (D3Y) −78 μC/g (D3M) −65 μC/g (D3C) −71 μC/g. As in Example 1, using these developers, 5,000 copies were continuously made on paper using an electrophotographic color copying machine using amorphous silicon as a photoreceptor. The resulting copy had many scratches in the fine line areas, and a good image could not be obtained.

The resolution was about 10 lines/mm.

(Effects of the Invention) As described above, the toner according to the present invention has excellent charging properties, flow properties, humidity dependence such as insulation properties, fixing properties, sharp melt properties, anti-offset properties, etc. It provides an image with excellent sharpness and, at the same time, excellent color reproducibility during colorization, with clear and good color tone.

Claims (1)

[Claims] (1) The main component is polyester resin, the glass transition point of the polyester resin is 40°C or higher, and the softening point is 80°C.
~150°C, and when the average particle size is D, particles with a diameter in the range of 0.5D to 2D account for 80% or more of the total on the number average, and the average particle size is 3~6μ
An electrophotographic toner characterized by being m.