JPH05158281A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To improve the fixability, color mixability and offset resistance in thermal fixing by using a binder resin with the clouding value of the resin dispersion specified. CONSTITUTION:This electrostatic charge image developing toner contains at least a colorant and a binder resin, and the clouding value of the dispersion of the binder resin is controlled to 7-30%. The toner becomes more transparent as the clouding value decreases, and this means that the opaque part in solvent, i.e., the aggregate insoluble in the solvent or weakly cross-linked material, is not present in the mixed solvent. Conversely, the higher clouding value means that a large amt. of an opaqueness forming component is present or the resin is highly cross-linked. A polyester resin is preferably used as the binder resin from the standpoint of fixability and developability, and an aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid is used as the bivalent acid component constituting the polyester resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner, and more particularly to a color toner, and more particularly to a color toner having high color reproducibility of a color image and being resistant to offset to a fixing roller.

[0002]

2. Description of the Related Art In recent years, full-color copying machines have been rapidly developed, and digitized full-color copying machines are being put on the market.

Color image formation by full-color electrophotography generally reproduces colors by using three color toners of three primary colors of yellow, magenta, and cyan, or four colors of black added thereto.

According to the general method, first, an electrostatic latent image is formed on a photoconductive layer by passing light from an original through a color separation light transmitting filter having a complementary color relationship with a toner color. Next, the toner is held on the support through a development and transfer process. Next, the above-mentioned steps are sequentially performed a plurality of times, the toners are superposed on the same support while matching the registration, and the final full-color image is obtained by fixing only once.

In the color electrophotographic method, in which a plurality of toner layers of different colors are superposed on the same support as the fixing step, the fixing characteristics are required to be possessed by the color toners. Is an extremely important factor.

That is, the fixed color toner is required to suppress diffused reflection due to toner particles as much as possible and to have an appropriate gloss and gloss.

Further, the color toner must have transparency and a wide color reproducibility so as not to interfere with toner layers having different color tones below the toner layer.

As a color toner satisfying these,
The present applicants have filed Japanese Patent Application Laid-Open Nos. 50-82442 and 5
No. 1,144,625 and Japanese Patent Laid-Open No. 59-57256 propose new combinations of color binder resins and colorants.

These color toners have a considerable sharp melt property, and when combined with a silicone rubber roller which can be coated with silicone oil, the toner shape changes to a state close to complete melting at the time of fixing, and a desirable gloss is obtained. And color reproducibility are obtained.

These effects mean that the viscous term is more important than the elastic term in the viscoelastic characteristic of the binder resin as the fixing characteristic of the toner.

That is, upon heating, the toner behaves more as a viscous material, the heat melting property is increased, and the glossiness is also obtained.

However, such a binder resin design emphasizing the viscosity term inevitably reduces intermolecular agglomeration at the time of heat fusion, and also increases toner adhesion to the heat roller when passing through the fixing device. become. These cause a high temperature offset phenomenon.

In particular, when a silicone rubber roller is used as a fixing roller, if it is repeatedly used regardless of whether or not the release oil is applied, a high temperature offset is likely to occur due to a reduction in the releasability of the surface of the silicone rubber roller. .. At the initial stage of use of the silicone rubber roller, some releasability can be maintained due to the silicone oil impregnated in the silicone rubber and the smoothness and cleanliness of the roller surface. However, the image area is large like a color image, and the toner holding amount on a support such as plain paper is much larger than that of a white / black copy image.
When copying is continued, naturally the oil in the silicone rubber is depleted, the surface of the roller becomes rough, and the releasability of the roller gradually decreases. The speed of deterioration of this releasability is white
It is several times more than black copy.

Further, since the toner itself has almost no elasticity as described above, it is useless for the offset resistance effect. As a result, a toner coating or granular deposits are formed on the surface of the fixing roller after a few thousand to tens of thousands of sheets, and the toner upper layer portion of the image surface is peeled off when passing through the heat roller. So-called high temperature offset occurs.

Various measures have been attempted with toners in order to solve or alleviate the above problems, but further improvements are desired. For example, JP-A-55-60960, JP-A-57-208559, and JP-A-58-1195.
No. 3, JP-A-58-14144, JP-A-SHO-60
As described in JP-A-123852, a method of adding low-molecular-weight polyethylene, polypropylene, wax, higher fatty acid, etc., which is a releasable component, to the toner is also used in order to increase the releasability. These methods are effective in preventing offset, but when contained in a large amount that sufficiently exhibits anti-offset properties, the compatibility with the main binder resin deteriorates and the transparency of the OHP image of the color toner is impaired. However, adverse effects such as unstable charging characteristics and reduced durability are also observed, and it is difficult to say that the charging characteristics are sufficient.

Further, JP-A-47-12334, JP-A-57-37353, and JP-A-57-208559.
Japanese Patent Laid-Open Publication No. 2003-242242, a monomer component containing an etherified bisphenol monomer, a dicarboxylic acid monomer, a trivalent or higher polyhydric alcohol monomer and / or a trivalent or higher polyvalent carboxylic acid monomer. A toner containing a polyester made of a non-linear copolymer obtained from the above as a binder has been proposed. However, such a technique has been proposed in which a polyester containing an etherified bisphenol monomer and a dicarboxylic acid monomer is used as a binder. Offsetting to the toner by incorporating as a binder a polyester obtained by crosslinking with a large amount of a monomer component containing a polyhydric alcohol monomer having a valence of 3 or more and / or a polycarboxylic acid monomer having a valence of 3 or more It has preventive performance. However, such a toner has a slightly high softening point, and therefore, it is difficult to perform good low-temperature fixing, and when used in full-color copying, it has a practically high temperature offset resistance. However, as described above, there are problems in fixing property and sharp melt property, and therefore good color mixing property and color reproducibility by superimposing color toners using the polyester are not desired. Further, JP-A-57-109825, JP-A-62-78568, and JP-A-62-78.
569 and the like, and in JP-A-59-7960 and JP-A-59-29256, an etherified bisphenol monomer, a dicarboxylic acid monomer into which a long chain aliphatic hydrocarbon is introduced, and others. A non-linear copolymer obtained from the dicarboxylic acid monomer and the monomer component containing a trivalent or higher polyvalent alcohol monomer and / or a trivalent or higher polyvalent carboxylic acid monomer. And its side chain has 3 to 3 carbon atoms
A toner containing 22 polyesters having saturated or unsaturated aliphatic hydrocarbon groups as a binder has been proposed. These polyester resins are mainly intended for high-speed copying toners.The viscoelastic properties of the resin are, contrary to the above-mentioned viscous polyester, strengthen the elasticity and prevent high temperature offset to the fixing roller. It has been significantly reduced. Then, at the time of fixing, the pressure and heating of the heat roller are increased as much as possible, and the toner is pressed in a semi-molten state between the fibers of the transfer paper to perform pressure heat fixing, thereby achieving the object. ..

Therefore, it is almost impossible to melt the toner layer to form a continuous film and obtain a smooth surface, which is necessary for color copying, and the fixed toner exists in a particle state on the transfer paper and is obtained. The color image becomes dull and the saturation is poor. In the OHP image, the light is scattered and diffused on the surface of the toner particles, almost no light is transmitted, and it becomes practically unusable.

Further, the present applicants have proposed a new polyester resin which is excellent in high temperature offset resistance and which can be applied to color copying in JP-A-2-73366 and JP-A-1-224767. However, the resin is superior to the conventional color toner resin, but the offset preventing effect on the fixing roller is exhibited at most about 20,000 copies repeatedly, and the offset preventing effect of the black and white toner is The number of sheets is 100,000 or more, and it is preferable to further improve the performance in view of the fact that the printing durability and the offset resistance of hundreds of thousands of sheets are currently available. In terms of electrification, the polyester has a large difference in electrification amount between a low-temperature low-humidity environment and a high-temperature high-humidity environment, and the density tends to be slightly low on the low-humidity side in a color image after repeated copying. Then, toner scattering and fog may occur.

Further, JP-A-62-195676, JP-A-62-195678, and JP-A-62-1956.
Japanese Patent Publication No. 80 discloses a polyester resin in which the ratio of the hydroxyl value and the acid value is specified, but these polyester resins are also intended for high-speed fixing,
According to the study by the present inventors, the color toner using the resin has not reached a point where sufficient color mixing property is obtained.

As a problem peculiar to color copying, at least 3
Color toners of four colors, preferably the color balance of four colors, must be in harmony, and it is meaningless to discuss the fixing characteristics and color reproducibility of only one color. It is necessary to design and select the resin in consideration of the above.

In principle, if there are three primary colors, yellow, magenta, and cyan, it should be possible to reproduce almost all colors by the primary color mixing method.
Therefore, the full-color copying machines on the market at present have a structure in which color toners of three primary colors are superposed and used. This should ideally be able to achieve all color tones in all density ranges, but in reality, there are still points to be improved, such as the spectral reflectance characteristics of toner, the mixing properties when toner is superimposed and fixed, and the decrease in saturation. have.

When a black color is obtained by superimposing three colors, a toner layer three times as much as that of a monochromatic color is formed on the transfer paper, and further it is difficult for the offset resistance.

[0023]

DISCLOSURE OF THE INVENTION It is an object of the present invention, in full-color copying, (1) shows good fixing property and color mixing property, (2) has sufficient triboelectric charging property, and (3) provides image quality. Remarkably high gloss, and (4) excellent durability with less carrier spent even after repeated copying.
(5) To provide a color toner in which high-temperature offset is sufficiently prevented, a fixable temperature range is wide, and (6) offset resistance is maintained even by repeated fixing paper passage.

The present invention is an electrophotographic toner comprising at least a colorant and a binder resin, wherein a binder resin having a resin dispersion having a haze value of 7 to 30% is used. Regarding

In the color toner of the present invention, the electrophotographic toner of the present invention uses a binder resin having the characteristics of both a linear resin and a non-linear cross-linking resin, which are so-called transient characteristics. It can be said that the toner. It is considered that, as a result, good color mixing and color reproducibility as a color toner were obtained, and offset resistance to the fixing roller was obtained.

That is, the reason why the preferred characteristics are obtained in the present invention is presumed as follows.

20 to 30 units of the crosslinking monomer component are regularly introduced into the repeating linear polymer chain at most one molecule to form weak crosslinking. And, although it is a weak crosslink, the whole polymer is constituted as one three-dimensional polymer. This provides much better offset resistance than a mixture of mere linear polymers. Moreover, the crosslinking level of the present invention is within a range that does not impede the easy mobility of the binder resin due to heat.

By limiting the composition and amount of the monomer components, a full-color image having good color mixture and color reproducibility can be obtained, and the offset resistance is not adversely affected. In the weakly cross-linked condensate, the amount of the cross-linking monomer component and the amount of the linear monomer component are determined so as to keep the balance, and if too much, abnormal sharp melt property is generated, and if too little, the color melt is generated. The gloss and saturation of the image are reduced.

The effects of the present invention will be described below while explaining the measuring method of the present invention.

(1) Method for measuring haze value of resin dispersion: The haze value of the resin dispersion is an important factor that supports the novelty and inventive step of the present invention.

That is, the basis of the judgment of whether or not the binder resin has the transient character having the degree of crosslinking having the characteristics of both the linear resin and the non-linear crosslinked resin, which is the gist of the present invention, It will be.

That is, conventionally, the so-called cross-linking degree of the so-called Soxhlet extraction is generally performed by dispersing the corresponding binder resin in a solvent of Toterahydrofuran, as disclosed by the present applicants in JP-A-63-223662. It was carried out for about 6 hours, and the tetrahydrofuran insoluble content was determined from the results, and this was used as a parameter indicating the degree of crosslinking of the binder resin. This method is effective when the binder resin has a very high degree of crosslinking, and is mainly used for high-speed copying machines as the binder resin for toner. It is essential to use a pressure heating fixing roller that has a high temperature offset property and applies high pressure and high temperature in order to maintain the fixing property.

The binder resin of the present invention is completely dissolved by this Soxhlet measurement method, and there is no insoluble matter. However,
When the binder resin of the present invention is used as a color toner,
It is clear that the color mixing property is excellent and the high temperature offset resistance is superior to the conventional one.

However, the inventors of the present invention
A new measuring method for measuring the degree of cross-linking was found, and it was confirmed that a binder resin that can satisfy the haze value in a specific range measured by the measuring method can achieve the object of the present invention, and the present invention has been reached. It is a thing. The method is shown below.

(1) Prepare a mixed solvent of xylene and isopropyl alcohol.

The mixing ratio of xylene and isopropyl alcohol is adjusted within the range of 1: 1 to 3: 1. The preferred mixing ratio is 2.5: 1.

(2) A binder resin as a sample is added to the above mixed solvent so that the concentration thereof is 5% by weight, and the mixture is mixed with the Turbula mixer for 0.2 to 2 minutes, preferably 0.5 to 1 minute. Disperse.

(3) This resin dispersion is filled in a transparent glass absorption cell having a haze value of 2% or less, preferably 1% or less.

(4) A model 1001DP type turbidimeter (Nippon Denshoku) or a SEP-T-SB type photoelectric photometer (Nippon Seimitsu Optical Co., Ltd.) equipped with the above-mentioned absorption cell filled with the dispersion liquid,
The total transmittance (T%) and the diffuse transmittance (D%) are calculated, and the haze value of the resin is calculated based on the following formula.

[0040]

[Outer 1]

The smaller the value of this haze value, the more transparent it is, and it means that there is no opaque portion in the mixed solvent, that is, there is no aggregate insoluble in the solvent, in other words, weak crosslinked material. On the contrary, the large haze value indicates that there are many components forming opacity, that is, the degree of crosslinking in the resin is high. Conventional crosslinkable polyesters show considerable crosslinkability, and are disclosed in JP-A-57-373.
53, JP-A-57-208559, JP-A-57-109825, and JP-A-62-195677.
The resin proposed in Japanese Patent Laid-Open Publication No. 1994-301 greatly exceeds the range of the present invention, and has a large haze value, which makes it unsuitable for use as a color toner.

Examples of the vinyl monomer component of the binder resin used in the present invention include styrene, chlorostyrene, α
-Methylstyrene, propylene, butadiene, styrene chloride, maleic acid, acrylic acid, methyl acrylate, butyl acrylate, propyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, butyl methacrylate, methacrylic acid There are propyl, ethyl methacrylate, phenyl methacrylate, maleic acid half ester, and acrylonitol.

Other vinyl monomer components having crosslinkability include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; diacrylate compounds linked by an alkyl chain such as ethylene glycol diacrylate and 1,3. -Butylene glycol diacrylate, 1,4-butanediol diacrylate,
1,5-Pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing the acrylates of the above compounds with methacrylates; diacrylates linked by an alkyl chain containing an ether bond. Compounds, for example
Diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and those obtained by replacing the acrylate of the above compounds with methacrylate; Diacrylate compounds linked by a chain containing an aromatic group and an ether bond, for example, polyoxyethylene (2) -2,2, bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2 ，
2-bis (4-hydroxyphenyl) propane diacrylate and those obtained by replacing the acrylates of the above compounds with methacrylates; as the polyfunctional crosslinking agent, pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane Triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate, and compounds obtained by replacing the acrylate of the above compounds with methacrylate; triallyl cyanurate, triallyl trimellitate, and the like.

Particularly in the present invention, from the viewpoint of fixability and developability, the binder resin preferably used is polyester resin, and the divalent acid component constituting the polyester resin is, for example, aromatic dicarboxylic acid. Examples of acids include terephthalic acid, isophthalic acid, phthalic acid, diphenyl-P.P'-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, naphthalene2.6-dicarboxylic acid, diphenylmethane-P.P'-dicarboxylic acid, and benzophenone. −
4,4′-dicarboxylic acid, 1,2-diphenoxyethane-P · P′-dicarboxylic acid and the like can be used, and other acids include maleic acid, fumaric acid, glital acid, cyclohexanedicarboxylic acid, succinic acid. , Malonic acid, adipic acid, mesaconinic acid, itaconic acid, citraconic acid, sebacic acid, anhydrides of these acids, and lower alkyl esters.

Examples of the acid or alcohol having an alkyl substituent or an alkenyl substituent used in the polyester resin of the present invention include an n-dodecenyl group, an isododecenyl group, an n-dodecyl group, an isododecyl group or an isooctyl group. , Maleic acid, fumaric acid, glutaric acid,
Examples include succinic acid, malonic acid, adipic acid, ethylene glycol 1,3-propylenediol, tetramethyl glycol, 1,4-butylenediol, and 1,5-pentyldiol.

As the dihydric alcohol,

[0047]

[Outside 2] [In the formula, R ¹ and R ² represent an alkylene group having 2 to 5 carbon atoms, X and Y represent a positive number, and X + Y represents 2 to 6. ] A diol such as an etherified bisphenol represented by For example, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl)
Propane, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroeoxyphenyl) propane, polyoxypropylene (13) -2,2
-Bis (4-hydroxyphenyl) propane.

Other dihydric alcohols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol,
Examples include diols such as 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, and hydrogenated bisphenol A. Be done.

Examples of tricarboxylic or higher polycarboxylic acids include trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acids, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxylic propane, 1,3-dicarboxylic-2
-Methyl-2-methylenecarboxylic propane, tetra (methylenecarboxylic) methane, 1,2,7,8-octanetetracarboxylic acid and their anhydrides can be used. Examples of trihydric or higher polyols include sorbitol, 1,2,3,6-hexanetetol and 1,4-
Sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,
4-Mesitatriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like can be used.

The production conditions of the polyester resin of the present invention are changed from the conventional ones, and the molecular weight distribution of the resin is particularly adjusted so as to be as sharp and narrow as possible. It is important to make the molecular chain distribution of the condensate in the polyester uniform within a narrow range in order to achieve both color mixing properties and offset resistance in the color toner. That is, a condensate having a short molecular chain with a small molecular weight is easily heated and its molecular main chain moves, while a condensate with a long molecular chain having a high molecular weight hardly moves by its thermal energy. When the imbalance is present in the polyester resin, when the color toner using the resin passes through the fixing roller at a low temperature, the low molecular weight condensate quickly melts and exhibits a behavior such as fixing and color mixing, Moreover, a phenomenon occurs in which the polymer condensate is almost insoluble.

On the other hand, when a temperature high enough to melt the polymer is applied to the fixing roller, the low molecule behaves as a viscous body having no elasticity at all, and causes a high temperature offset.

Therefore, especially in color toners, the ratio of the weight average molecular weight to the number average molecular weight is set in order to have a relatively sharp melt property and to enhance intermolecular aggregation of the polyester resin constituting the toner. It should be as small as possible. This is a more important attribute than discussed with black and white toner.

Colorants suitable for the purposes of the present invention include the following pigments or dyes. In the present invention, C.I. I. Disperse Yellow
164; C.I. I. Solvent Yellow 77
And C.I. I. Colorants such as Solvent Yellow 93 are non-advancing.

Examples of the dye include C.I. I. Direct Red 1; C.I. I. Direct Red 4; C.I. I. Acid Red 1; C.I. I. Basic Red 1; C.I.
I. Mordant Red 30; C.I. I. Direct Blue 1; C.I. I. Direct Blue 2; C.I. I. Acid Blue 9; C.I. I. Acid Blue 15; C.I. I. Basic Blue 3; C.I. I. Basic Blue 5; C.I. I.
Modant Blue 7 etc.

Examples of pigments include Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 38, Fast Bio Red B, Methyl. There are violet red lake, phthalocyanine blue, fast sky blue, induslen blue BC, etc.

Disazo yellow, an insoluble azo pigment, and copper phthalocyanine are preferably used as the pigment, and basic dyes and oil-soluble dyes are suitable as the dye.

Particularly preferably, C.I. I. Pigment Yellow 17; C.I. I. Pigment Yellow 15; C.I. I. Pigment Yellow 13; C.I. I. Pigment Yellow 1
4; C.I. I. Pigment Yellow 12; C.I. I. Pigment Red 5; C.I. I. Pigment Red 3; C.I. I.
Pigment Red 2; C.I. I. Pigment Red 6;
C. I. Pigment Red 7; C.I. I. Pigment Blue 15; C.I. I. Pigment Blue 16 or a copper phthalocyanine-based pigment having the structural formula (1) shown below, in which the phthalocyanine skeleton is substituted with 2 to 3 substituents.

[0058]

[Outside 3] [Wherein X ₁ , X ₂ , X ₃ and X ₄ are

[0059]

[Outside 4] Or H is shown. However, the case where all of X _{1 to} X ₄ are -H is excluded. ]

As the dye, C.I. I. Solvent Red 49; C.I. I. Solvent Red 52; C.I. I. Solvent Red 109; C.I. I. Basic Red 12;
C. I. Basic Red 1; C.I. I. For example, Basic Red 3b.

Regarding the content of yellow toner, which is sensitive to the transparency of the OHP film,
12 parts by weight or less based on 100 parts by weight of the binder resin,
It is preferably 0.5 to 7 parts by weight.

When the amount is 12 parts by weight or more, the reproducibility of green and red, which are mixed colors of yellow, and human skin color as an image is poor.

For the other magenta and cyan color toners, the amount is 15 parts by weight or less, more preferably 0.1 to 9 parts by weight, based on 100 parts by weight of the binder resin.

It is also preferable to add a charge control agent to the toner according to the present invention in order to stabilize the negative charge characteristic. At that time, a colorless or light-colored negative charge control agent that does not affect the color tone of the toner is preferable.

The carrier used in the present invention includes, for example, surface-oxidized or non-oxidized metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium and rare earths, their alloys or oxides and magnetic ferrites. Can be used. Moreover, there is no particular restriction as to the manufacturing method thereof.

A system in which the surface of the carrier is dipped in a resin or the like is particularly preferable. Examples of the method include a method of dissolving or suspending a coating material such as a resin in a dissolving agent and applying it to a carrier, and a method of simply mixing with a powder.
Any of the conventional Kochi methods can be applied.

The substance adhered to the surface of the carrier varies depending on the toner material. For example, polytetralfluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, styrene resin, acrylic resin, polyacid. , Polyvinyl butyral, nigrosine, amino arc rate resin,
It is suitable to use a basic dye and its lake, a fine silica powder, a fine alumina powder, a metal complex or a metal salt of dialkylsalicylic acid, alone or in combination.

The treatment of the above compounds may be appropriately determined so that the carrier satisfies the above conditions, but generally, the total amount is 0.1 to 30% by weight (preferably 0.5) with respect to the carrier of the present invention. ˜20% by weight) is preferred.

The average particle size of these carriers is 20 to 100.
μ, preferably 25 to 70 μ, more preferably 25 to 6
It is preferable to have 5μ.

In a particularly preferred embodiment, Cu-Zn-
Fe ternary ferrite, the surface of which is a combination of resins such as fluorine resin and styrene resin, for example, polyvinylidene fluoride and styrene-methyl methacrylate resin; polytetrafluoroethylene and styrene-methyl methacrylate resin Fluorine-based copolymer; etc. 9
0:10 to 20:80, preferably 70:30 to 30:
70% mixture, 0.01 to 5% by weight, preferably 0.1 to 1% by weight, 25
An example is a coated magnetic ferrite carrier having the above-mentioned average particle size in which carrier particles of 0 mesh pass and 350 mesh on are 70% by weight or more. Examples of the fluorine-based copolymer include vinylidene fluoride-tetrafluoroeletin copolymer (10:90 to 90:10), and examples of the styrene-based copolymer include styrene-2-ethylhexyl acrylate copolymer ( 20: 80-80: 2
0), a styrene-acrylic acid-ethylhexine-methyl methacrylate copolymer (20-60: 530: 10-5).
0) is exemplified.

The above-mentioned coated ferrite carrier has a sharp particle size distribution, and it is possible to obtain a preferable triboelectrification property for the toner of the present invention and to improve electrophotographic characteristics.

When a two-component developer is prepared by mixing with the toner according to the present invention, the mixing ratio is 1% by weight to 15% by weight, preferably 2% by weight to 13% by weight, as the toner concentration in the developer. %, Usually good results are obtained. If the toner concentration is less than 1% by weight, the image density tends to be low, and if it exceeds 15% by weight, fog and in-machine scattering tend to increase, and the useful life of the developer tends to be shortened.

As the fluidity improver used in the present invention, any fluidity improver can be used as long as it can be added to the colorant-containing resin particles to increase the fluidity before and after the addition. For example, hydrophobic colloidal silica fine powder,
Examples thereof include colloidal silica fine powder, hydrophobic titanium oxide fine powder, titanium oxide fine powder, hydrophobic alumina fine powder, alumina fine powder, and mixed powder thereof.

Other methods for measuring physical properties according to the present invention will be described below.

(2) Measurement of glass transition temperature Tg In the present invention, measurement is performed using a differential thermal analysis measuring device (DSC measuring device), DSC-7 (manufactured by Perkin Elmer Co.).

The measurement sample is 5 to 20 mg, preferably 10
Precisely weigh mg.

This is put in an aluminum pan, an empty aluminum pan is used as a reference, and the following operation is performed for the purpose of first erasing the previous history. Room temperature to 200 in N ₂ atmosphere
The temperature is raised to 10 ° C./min and kept at 200 ° C. for 10 minutes. Then, it is rapidly cooled, the temperature is lowered to 10 ° C., and the temperature is kept at 10 ° C. for 10 minutes. Then, at a temperature rising rate of 10 ° C./min, 2
Raise the temperature to 00 ° C. During this temperature raising process, the temperature of 40 to 10
An endothermic peak of the main peak in the range of 0 ° C is obtained.

The crossing point between the line at the midpoint of the pace line before and after the appearance of the endothermic peak at this time and the differential heat curve is defined as the glass transition temperature Tg in the present invention (see FIG. 2).

(3) Measurement of weight average molecular weight (Mw) and number average molecular weight (Mn): In the present invention, HLC-802.
Mw and Mn are measured using A type (made by Toyo Soda Co., Ltd.). The column is TSKgel GMH manufactured by Toyo Soda Kogyo Co., Ltd.
6x2 is used and THF is used as the solvent. The detector is R
I (refractive index) is used, the sample is injected at a concentration of 0.5%, and the injection volume is 200 μl.

The molecular weight of the sample is calculated from the relationship between the logarithmic value and the number of counts of the calibration curve prepared by using several kinds of monodisperse polystyrene standard samples for the molecular weight distribution of the sample.

As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical C
o. Made or manufactured by Toyo Soda Kogyo Co., Ltd. has a molecular weight of 6 × 1
0 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ ,
5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.
It is suitable to use those of 6 × 10 ⁵ , 5 × 10 ⁶ and 4.48 × 10 ⁶ , and to use at least about 10 standard polystyrene samples.

(4) Measurement of hydroxyl value: JIS K007
The measurement is carried out by the following method according to the method shown in.

6 g of the sample was placed in a 200 ml Erlenmeyer flask for 1 m.
Accurately weigh in g, add 5 ml of a mixed solution of acetic anhydride / pyridine = 1/4 with a hole pipette, and add pyridine 25
Add ml with a graduated cylinder. A condenser is attached to the Erlenmeyer flask mouth, and the reaction is performed in an oil bath at 100 ° C. for 90 minutes.

3 ml of distilled water was added from the top of the cooler, shaken well and left for 10 minutes. With the condenser attached, the Erlenmeyer flask is pulled up from the oil bath and allowed to cool. When the temperature reaches about 30 ° C., the condenser and the flask outlet are washed with a small amount of acetone (about 10 ml) from the condenser upper opening. THF50
ml is added with a graduated cylinder, and neutralization titration is carried out with an N / 2KOH-THF solution as an indicator using an alcohol solution of phenolphthalein as a indicator using a 50 ml (scale 0.1 ml) burette. 25 ml of neutral alcohol just before the end point of neutralization
(Methanol / acetone = 1/1 volume ratio) is added and titration is carried out until the solution becomes slightly red. At the same time, perform a blank test.

Then, the hydroxyl value is calculated according to the following formula.

[0086]

[Outside 5] Where A: ml of N / 2KOH-THF solution required for this test B: ml of N / 2KOH-THF solution required for blank test f: titer of N / 2KOH-THF solution S: sampled amount (G) C: acid value or alkali value. However, the acid value is positive and the alkali value is negative. The average of the two measurements is used.

(5) Gloss (glossiness) measuring method: VG-1
Using a 0 type gloss meter (manufactured by Nippon Denshoku Co., Ltd.), each solid image used for chromaticity measurement is used as a sample for measurement.

For the measurement, first, 6 V was measured by a constant voltage device.
Set to.

Next, the projection angle and the reception angle are set to 60
Set to °.

Using the zero point adjustment and the standard plate, after the standard setting, the sample image is placed on the sample table, and the white paper is 3
Perform overlay measurement on a sheet and read the value shown in the marking section in%.

At this time, the S / S / 10 switch SW is set to S, and the angle / sensitivity switch SW is set to 45-60.

A sample having an image density of 1.5 ± 0.1 is used.

The production method for obtaining the polyester resin of the present invention is, for example, as follows.

First, a linear condensate is formed, the molecular weight is adjusted to 1.5 to 3 times the target acid value and hydroxyl value in the process, and the molecular weight is made slower than before so that the molecular weight becomes uniform. , So that the condensation reaction proceeds gradually, for example, by reacting at a lower temperature for a longer time than before, or by reducing the esterifying agent, or using an esterifying agent having low reactivity, or combining these methods. The reaction is controlled by using Then, under the conditions, a crosslinking acid component and, if necessary, an esterifying agent are further added to react with each other to form a three-dimensional condensate. When the temperature is further raised, the reaction is slowly and long-term so that the molecular weight distribution becomes uniform, the crosslinking reaction proceeds, the reaction is terminated when the hydroxyl value falls to a target value, and the conditions for the binder resin of the present invention are satisfied. Obtain a polyester resin.

Next, an example of a full-color electronic copying machine to which the electrophotographic method using the color toner of the present invention is applied will be described with reference to FIG.

The electrostatic latent image formed on the photosensitive drum 1 by an appropriate means is visualized by the developer in the developing device 2-1 attached to the rotary developing unit 2 rotating in the direction of the arrow. The developing toner is transferred by the transfer charger 8 onto the transfer material held on the transfer drum 6 by the gripper 7.

Next, the rotary developing unit for the second color rotates, and the developing device 2-2 faces the photosensitive drum 1. Then, the toner image is developed by the developer in the developing device 2-2, and this toner image is also transferred onto the same transfer material as described above.

Further, the third and fourth colors are similarly processed.
In this way, the transfer drum 6 is rotated a predetermined number of times while gripping the transfer material, and images of a predetermined number of colors are transferred in multiple. The transfer current for electrostatic transfer is preferably increased in the order of the first color <second color <third color <fourth color in order to reduce transfer residual toner. The multiple-transferred transfer material is separated from the transfer drum 6 by a separation charging device 9, and passes through a heating and pressure roller fixing device 10 to form a full-color copy image.

The replenishment toner supplied to the developing units 2-1 to 2-4 is supplied from the replenishment hopper 3 provided for each color.
A certain amount based on the replenishment signal is passed through the toner conveying cable 4 and the toner replenishing cylinder 5 at the center of the rotary developing unit 2
And sent to each developing device. This replenishment toner is uniformly mixed with the developer in the developing device in advance so as to have a predetermined developer concentration by the mixing-conveying screw in the developing device.

At this time, the mixing ratio of the carrier and the toner is an extremely important factor from the viewpoint of the developing effect.

The developer adhering to the surface of the sleeve containing the magnet rubs against the electrostatic latent image to make the latent image visible with toner. As a result, the toner is gradually consumed from the developer, the ratio of the toner to the carrier decreases, that is, the density of the developer decreases, and the density of the developed image gradually decreases. Therefore, the toner is appropriately replenished, but in this case, if the toner is replenished more than the proper amount, the density of the image becomes too high and the fog increases. Therefore, it is necessary to accurately detect the concentration of the developer in order to continuously obtain images of a desired color tone.

[0102]

The present invention will be described in detail with reference to the following examples.

Production Example of Polyester Resin-1 terephthalic acid 2 mol, adipic acid 1.0 mol, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 3.0 mol, dibutyltin oxide. 02 g was placed in a glass 21 four-necked flask, and a thermometer, a stir bar, a condenser, and a nitrogen inlet tube were attached and placed in a mantle heater. Next, after replacing the inside of the flask with nitrogen gas, gradually raising the temperature while stirring,
The reaction was carried out at 160 ° C for 7 hours, then the temperature was raised to 190 ° C and the reaction was carried out for 5 hours.

Then, 0.2 mol of glycerin and 0.04 g of dibutyltin oxide were added, and the mixture was reacted at 190 ° C. for 3 hours, further heated to 200 ° C. and reacted for 5 hours to complete the reaction. Resin (1) was obtained. The weight average molecular weight (Mw) of the obtained polyester resin (1) is 14400, the number average molecular weight is 5750, Mw / Mn is 2.5, the hydroxyl value is 14.6, and the haze value is It was 17%.

Production Example of Polyester Resin-2 Isophthalic Acid 1.8 mol, Malonic Acid 1.16 mol,
1.3 mol of 1,3-propylene diol, 1.0 mol of ethylene glycol and neopentyl glycol of 0.
5 mol were reacted in a nitrogen atmosphere in the same manner as in Production Example-1. Next, pyromellitic dianhydride 0.1mo
1,9 Dibutyltin oxide (0.09 g) was added and the reaction was carried out at 180 ° C. for 5 hours to obtain the polyester resin (2) of the present invention. The Mw of the obtained polyester resin (2) is 1870.
0, Mn is 5670, and Mw / Mn is 3.3.
The hydroxyl value was 18.5 and the haze value was 9%.

Production Example of Polyester Resin-3 Polyoxypropylene (2.2) -2,2-bis (4-)
Hydroxyphenyl) propane 2.0 mol, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane 2.1 mol, terephthalic acid 2 mo
l, dodecenyl succinic acid 1.6 mol, trimellitic acid 0.46 mol, using the same device as in Production Example-1
A polyester resin (3) was obtained by reacting at 0 ° C. for 8 hours.

The polyester resin (3) has a weight average molecular weight (Mw) of 110000 and a number average molecular weight (M
n) is 5540 and the ratio (Mw / Mn) is 16.
2, the hydroxyl value was 20.4, and the haze value was 35%. The glass transition temperature was 61.5 ° C.

Production Example of Polyester Resin-4 Polyoxypropylene (2.2) -2,2-bis (4-)
Hydroxyphenyl) propane 5 mol, fumaric acid 4.
5 mol and 0.1 g of hydroquinone were reacted at 220 ° C. in a nitrogen stream using the same apparatus as in Production Example-1 to obtain a polyester resin (4).

The polyester resin (4) thus obtained had a weight average molecular weight (Mw) of 18,700, a number average molecular weight (Mn) of 3270, Mw / Mn of about 5.7 and a hydroxyl value of 32. It was 0 and the haze value was 3.0%.

Example 1 100 parts by weight of the polyester resin (1) of Preparation Example 1 4 parts by weight of a copper phthalocyanine pigment having the structural formula (I) (disubstituted product) 3.5-ditertiary-butyl chromium salicylate Complex 4 parts by weight

The above materials were sufficiently premixed with a Henschel mixer, melt-kneaded with a twin-screw extrusion kneader, cooled, and roughly crushed to about 1 to 2 mm with a hammer mill,
Then, it was pulverized to a particle size of 40 μm or less by an air jet pulverizer. Further, the finely pulverized product obtained is classified, and selected so that the volume average diameter in the particle size distribution is 8.2μ to obtain a classified product (cyan color toner), which is treated with hexamethyldisilazane as a fluidity improver. 0.8 part by weight of the silica fine powder was externally added to 100 parts by weight of the classified product, and 0.5 part by weight of aluminum oxide fine powder was further added to obtain a cyan color toner.

Further, about 5.0 parts by weight of this cyan color toner was coated with about 0.35% by weight of styrene-methyl methacrylate (copolymer weight ratio of 65:35) Cu-Zn-Fe type ferrite carrier. The developer was mixed so that the total amount would be 100 parts by weight. The toner concentration in the developer was 5.0% by weight.

A copying test was conducted using a color electrophotographic apparatus having an OPC photosensitive drum shown in FIG. At this time, the fixing roller used in the fixing device 7 had a single layer of HTV silicone rubber layer having a thickness of 1 mm on the core metal, and the pressure roller surface was made of HTV silicone rubber having a thickness of 3 mm.

An initial image was obtained using this method, but the color tone was vivid with excellent saturation.

Further, even after printing 90,000 sheets, a cyan image which faithfully reproduces the original without fog was obtained.
Further, conveyance in the copying machine and detection of developer concentration were good, and stable image density was obtained. Fixing temperature setting 150 ℃ 9
Even after repeatedly copying ten thousand sheets, offset to the fixing roller did not occur at all.

Further, in order to compare and measure the high temperature offset amount, a new fixing roller was provided in the fixing device 7. The driving of the silicone oil-impregnated web was stopped, and in that state, an image having an area ratio of 20% was used as an original, and 5,000 sheets were repeatedly copied. Then, in order to quantify the toner adhered to the web, that is, the so-called high temperature offset toner, the portion was measured with a Macbeth reflection densitometer, and the density was 0.3.

In this method, if the high temperature offset amount is large,
The reflection density value of the toner-adhering web increases and decreases when it is small, so that the high temperature offset is quantified.

The charge amount was measured in each of the low temperature and low humidity (15 ° C. 10% RH) and high temperature and high humidity (32.5 ° C. 85% RH) environments.
The charge amount ratio according to the environment was 1.20.

As a method of evaluating a color copied image, there is a method of determining the quality of a color image by measuring the gloss (glossiness) of the image surface. That is, it is determined that the higher the gloss value is, the smoother and glossier the color quality of the image surface is, and the lower the gloss value is, the more the image surface having the dull saturation is blurred.
The measuring method is as follows, and the value in Example 1 was 15%. The results are shown in Table 1.

Example 2 100 parts by weight of polyester resin (1) of Production Example-1 C.I. I. Pigment Red 122 5 parts by weight 3,5-ditertiary butylsalicylic acid chromium complex 4 parts by weight

A magenta toner was prepared in the same manner as in Example 1 using the above materials, and a magenta toner image was obtained in the same manner as in Example 1. The obtained image had a bright magenta color with high image density. Next, a durability test was carried out, and it was a good image without toner offset to the fixing roller and graze even at 90,000 sheets. The results are shown in Table 1.

Example 3 100 parts by weight of polyester resin (2) of Production Example-1 C.I. I. Pigment Yellow 17 3.5 parts by weight 3,5-ditertiary butyl salicylic acid chloro complex
4 parts by weight

Using the above materials, a yellow toner was prepared in the same manner as in Example 1, and a yellow toner image was obtained in the same manner as in Example 1. The obtained image was a bright yellow color with high image density. Next, a durability test was carried out, and it was a good image without toner offset to the fixing roller and graze even at 90,000 sheets. The results are shown in Table 1.

Comparative Examples 1 and 2 Tests were conducted in the same manner as in Example 1 except that the polyester resins (3) and (4) were used. The results of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1.

[0125]

[Table 1] Example 4 The polyester resin (1) of Production Example-1 was used, and a colorant was further added by C.I. I. Pigment Yellow 17 (3.5 parts by weight), the yellow toner prepared in the same manner as in Example 1, the magenta toner of Example 2, and the cyan toner of Example 1 were used for each of the three primary color toners. 35%
Using the above image as an original, a color electrophotographic apparatus as shown in Example 1 was used and repeated copying in full color was performed, but durability of a large number of 70,000 sheets or more was recognized.
Substantially no offset to the fixing roller was observed.

Even in the full-color copied image after 70,000 sheets, the color mixture was excellent and the saturation was high. The gloss value of solid black obtained by superimposing three colors was 20%.

According to the present invention, by using as the binder resin a resin which is crosslinked but has a narrow molecular weight distribution, a color having excellent color mixing property at the time of heat fixing and excellent offset resistance. Toner may be provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a full-color copying machine using color toner.

FIG. 2 is an explanatory diagram regarding a glass transition point of resin or toner.

[Explanation of symbols]

 1 Photosensitive Drum 2 Rotational Development Unit 3 Replenishment Hopper 4 Toner Transport Cable 5 Toner Replenishment Tube 6 Transfer Drum 7 Gripper 8 Transfer Charger 9 Separation Charger 10 Heat Press Roller Fixer 13 Development Sleeve 16 Supply Screw

Claims (2)

[Claims] 1. An electrostatic image developing toner containing at least a colorant and a binder resin, wherein the binder resin has a haze value of 7 to 30% of a dispersion liquid of the binder resin. Toner for charge image development. 2. The toner for developing an electrostatic charge image according to claim 1, wherein the binder resin is formed of a polyester resin.