JPH02285362A - Developing agent for electrostatic image - Google Patents

Abstract

PURPOSE:To prevent the destruction of toner particles and to exhibit positive triboelectrostatic chargeability stable over a long period of time by incorporating the polyester obtd. by bringing a monomer compsn. contg. specific components into a polycondensation reaction as a binder resin into the toner. CONSTITUTION:The polyester obtd. by bringing the monomer compsn. contg. the three components; a tervalent and higher valency monomer, arom. dicarboxylic acid and aliphat. dialcohol, into the polycondensation reaction is incorporated as the binder of the toner into the toner. The flexibility of the molecule chains in the polyester is improved particularly by the aliphat. dialcohol component. The mechanical energy by the agitation, etc., of a developer is, therefore, converted to the kinetic energy of the molecular chains of the polyester. The mechanical stresses that the toner particles receive are extremely relieved in this way, by which the destruction of the toner particles is effectively prevented and the triboelectrostatic chargeability of the toner is stabilized even in the case of forming images many times.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to developing an electrostatic latent image formed on the surface of a latent image carrier in, for example, electrophotography, electrostatic recording, electrostatic printing, etc. The invention relates to an electrostatic image developer used for

[Technology background]

At present, as a method for forming a visible image from certain image information, methods using electrostatic latent images, such as electrophotography, electrostatic recording, and electrostatic printing, are widely used.

For example, in electrophotography, a latent image carrier having a photosensitive layer made of a photoconductive material is given an electrostatic charge, and then image exposure causes the surface of the latent image carrier to correspond to the original. An electrostatic latent image is formed, and this electrostatic latent image is developed with a developer to form a toner image. After this toner image is transferred to a recording material such as paper, it is fixed by heating or pressure to form a copy image. On the other hand, after the transfer process, the latent image carrier is neutralized, toner remaining on the latent image carrier without being transferred is cleaned, and then the toner is used for forming the next copy image.

Therefore, in order to stably form a good copy image with high image density and no fog over many times, the triboelectric charge of the toner must always be within an appropriate range. It is important to effectively prevent contamination of carriers or developer carriers due to the above.

[Conventional technology]

In response to such a request, the following techniques have been proposed in the past.

■An electrostatic image developer composed of toner particles containing polyester with a chloroform-insoluble content of 5 to 25% by weight as a binder resin, inorganic fine particles consisting of negatively charged silica fine particles, and a fluororesin-coated carrier. Agent (Unexamined Japanese Patent Publication 1986)
(Refer to Publication No.-176052).

■Toner particles containing polyester with a chloroform-insoluble content of 5 to 25% by weight as a binder resin, positively charged inorganic particles made of alumina particles, titanium oxide particles, nitrogen-containing silica particles, etc., and fluorine resin Electrostatic image developer composed of a coated carrier (JP-A-62-2
(See Publication No. 29158).

[Problem to be solved by the invention]

However, the above technology has the following problems.

In the above technology (2), negatively chargeable silica particles are used, so even if a fluororesin-coated carrier with strong negative chargeability is used, the triboelectricity of the toner particles does not rise well, and if images are formed many times. However, there is a problem in that toner scattering occurs in the developing section, contaminating the charging electrode, transfer electrode, separation electrode, etc., resulting in defective images. When the amount of toner scattering increases,
The back side of the leading edge of the transfer material is smeared with toner, which occurs.

In addition, since the polyester used as the binder resin is highly brittle, when subjected to mechanical external force such as stirring in the developing device, the toner particles are easily destroyed and fine powder is generated, and this fine powder adheres to the surface of the carrier particles. Therefore, there is a problem that so-called toner spent occurs, in which the triboelectric charging properties between the toner and the carrier become unstable.

In the above technology (2), since positively chargeable inorganic fine particles are used, the triboelectric charging properties of the toner particles are improved, and toner scattering is therefore reduced. The toner particles are likely to be destroyed by mechanical external forces such as stirring inside the toner and generate fine powder, and this fine powder adheres to the surface of the carrier particles, making the triboelectrification between the toner and the carrier unstable, and as a result. There are problems in that image defects such as toner scattering and fogging occur due to a decrease in the amount of triboelectric charge of toner particles and a worsening of the rise of triboelectric charge.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide an electrostatic image developer that is unlikely to cause destruction of toner particles and exhibits stable positive triboelectric charging properties over a long period of time. shall be.

[Means to solve the problem]

To achieve the above object, the present invention provides an electrostatic image developer comprising a toner and inorganic fine particles treated with a nitrogen-containing substance, wherein the toner contains the following components [1] to [
It is characterized in that it contains a polyester obtained by subjecting a monomer composition containing [3] to a polycondensation reaction as a binder resin.

Component 08 Polyvalent monomer component with a valency of 3 or higher [2]; Aromatic dicarboxylic acid component [3]; Fatty dialcohol Also, acid value (AV) and hydroxyl value (OHV) of polyester
) is preferably 30 or more and 80 or less.

[Effect]

The polyester used as the binder resin of the toner is a polyester obtained by subjecting a monomer composition containing a trivalent or higher valent monomer, an aromatic dicarboxylic acid, and an aliphatic dialcohol to a polycondensation reaction, and in particular Since an aliphatic dialcohol is used instead of the conventionally used bisphenol alcohol, the flexibility of the molecular chain in the polyester is improved. Therefore, mechanical energy caused by stirring the developer, etc. is converted into kinetic energy of the molecular chains of the polyester, and as a result, the mechanical stress on the toner particles is considerably alleviated, effectively preventing the destruction of the toner particles. be done.

Therefore, the triboelectric charging properties of the toner are stable even when images are formed many times, and the presence of inorganic fine particles treated with a nitrogen-containing substance significantly improves the rise of the triboelectric charging properties of the toner. is demonstrated stably over a long period of time.

In addition, the polyester whose sum of AV and OHV is within the range of 30 to 80 has a property that the binder resin itself is difficult to crush, so the image density is high, and this state can be stably obtained. A highly reliable copy image without capri is obtained. In addition, a copy image having excellent fixing properties, offset resistance, and wrapping resistance can be obtained.

[Specific structure of the invention]

Hereinafter, the configuration of the present invention will be specifically explained.

In the present invention, a polyester (hereinafter also referred to as "specific polyester") obtained by subjecting a monomer composition containing the components [1] to [3] to a polycondensation reaction is used as the binder resin.

Examples of the trivalent or higher polyvalent monomer which is component (1) include 1. 2. 4-benzenetricarboxylic acid, 1.3.
5-benzenetricarboxylic acid, 1,2°4-cyclohexanetricarboxylic acid, 2. 5. 7-naphthalene tricarboxylic acid, 1.2.4-naphthalene tricarboxylic acid,
1. 2. 4-butanetricarboxylic acid, 1. 2.
5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxy)methane, 1. 2. 7.
8-octane tetracarboxylic acid, empol trimer acid,
Examples include anhydrides and esters of these acids.

Among these trivalent or higher polyvalent monomers, aromatic polycarboxylic acids are particularly preferred in the polyester using an aliphatic dialcohol as in the present application, and benzenetricarboxylic acid, anhydrides of these acids or Benzenetricarboxylic acids such as esters can provide stable triboelectric charging properties.

The blending ratio of the trivalent or higher polyvalent monomer is preferably 1 to 304% of the total monomer composition. By using a polyester within this range, wax separation can be further prevented. The reason for this is that the polyester in this range has good compatibility with wax having a low molecular weight, so that the wax is finely and uniformly dispersed in the resin, and the adhesive strength with the resin is improved. More preferably, it is 1 to 15 mol% of the total monomer composition.

Examples of the aromatic dicarboxylic acid of component (2) include phthalic acid, isophthalic acid, terephthalic acid, and anhydrides or esters of these acids.

Other dicarboxylic acids may be used in combination with the above aromatic dicarboxylic acids. Such other dicarboxylic acids include, for example, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, cepacic acid,
Examples include malonic acid, anhydrides or lower alkyl esters of these acids, dimers of liluic acid, and other difunctional organic acid monomers. The blending ratio of such other dicarboxylic acids is preferably 30 mol % or less of the total dicarboxylic acids. When the blending ratio of the other dicarboxylic acid is too large, the glass transition point Tg of the specific polyester tends to decrease, resulting in a decrease in image density.

The aliphatic dialcohol of component (1) is preferably an aliphatic dialcohol having 2 to 10 carbon atoms in order to provide a toner with even less amount of toner particles spent on the carrier surface.

When the number of carbon atoms in the aliphatic dialcohol is less than 2, the flexibility of the molecular chain is insufficient, and when it exceeds 10, the flexibility of the molecular chain is sufficient and it is easy to prevent the formation of fine powder. It is easy to undergo plastic deformation on the carrier, and as a result, it is easy to induce toner spent. Furthermore, when the number of carbon atoms exceeds 10, the glass transition point Tg decreases sharply, and therefore toner lumps are likely to be formed in the developing device.
As a result, triboelectric charging properties become poor and toner scattering tends to occur.

In addition, in the aliphatic dialcohol of component (1), in order to further prevent the formation of fine powder, it is particularly preferable that the aliphatic dialcohol having a branched chain is 50 mol % or more of the total aliphatic dialcohol. Here, a branched chain is two OH
Refers to the other carbon chains when the main chain is a straight chain connected by carbons between groups.

When the content of such a branched aliphatic dialcohol is 50 mol % or more, the concentration of ester bonds in the polyester is reduced, the amount of water absorbed can be kept low, and it is considered to be effective in preventing deterioration.

Specific examples of aliphatic dialcohols include (1) Branched aliphatic dialcohols include 1.2-propanediol, 1.2-butanediol, 1.3-butanediol, 2.3- Butanediol, neopentyl glycol, 1.2-hexanediol, 2.5-hexanediol, 2-methyl-2,4-bentanediol,
3-methyl-1,5-bentanediol, 2-ethyl-
1゜3-hexanediol etc. can be mentioned, (2
) Examples of aliphatic dialcohols without branched chains include ethylene glycol, 1.3-propanediol, 1.4-
Butanediol, diethylene glycol, 2-butene-
1,4-diol, 1.5-bentanediol, 1.6
-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol, pentaethylene glycol and the like.

Other dialcohols may be used in combination with the above aliphatic dialcohols. All such other dialcohols include, for example, 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A1, hydrogenated bisphenol A
Other bifunctional alcohol monomers such as etherified bisphenols such as 1-polyoxyethylenated bisphenol A1 and polyoxypropylenated bisphenol A can be mentioned. The blending ratio of such other dialcohols is preferably 30 mol % or less based on the total dialcohols. When the blending ratio of the other dialcohol is excessive,
The flexibility of the molecular chain is low, and toner fine powder is likely to be generated, which deteriorates the durability of the developer.

Further, the sum of acid value (AV) and hydroxyl value (OHV) of the polyester used in the present invention is preferably 30 or more and 80 or less.

Here, the acid value (AV) refers to the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of sample. Additionally, the hydroxyl value (OHV) refers to the milligrams of potassium hydroxide required to neutralize acetic acid bound to hydroxyl groups when acetylating 1 g of a sample according to the standard oil and fat analysis test method (Nippon Yushi Kagaku Kyōyōsen). refers to a number.

In polyester, the sum of AV and OHV means the number of terminal groups in the polymer molecular chain.
The polyester whose sum of HV is in the range of 30 or more and 80 or less has the property of being difficult to crush in the binder resin itself, so it is possible to stably obtain high image density and this state, and to avoid fogging. A highly reliable copy image with no blemishes can be obtained.

In addition, a copy image having excellent fixing properties, offset resistance, and wrapping resistance can be obtained.

When the sum of AV and OHV (AV+0HV) is less than 30, the molecular weight of the polyester, that is, the binder resin, becomes too large, and therefore the melt viscosity during kneading becomes too large, causing the colorant to fall off from the beginning after pulverization and classification. These additives are present in the toner, which tends to contaminate the surfaces of the latent image carrier, carrier, developer carrier, etc.

For the specific polyester, in order to further prevent a decrease in image density and fog, the OHV/AV value should be 5.
It is preferable to select a value of 0 or less, more preferably 2.0 or less. More preferably, it is less than 1.2. The reason for this is not clear, but when the value of OHV/AV is large, self-crosslinking tends to proceed rapidly during crosstalk, so the melt viscosity increases dramatically, and the viscosity difference between the toner and additive becomes more negative. This is thought to be because the layer becomes larger and the additives that have fallen off after pulverization and classification are present in the toner.

Furthermore, the softening point Tsp of the specific polyester is 90
-170 degreeC is preferable, and 100-160 degreeC is more preferable. When the softening point Tsp is too small, toner particles are easily destroyed and fine powder is easily generated (which promotes spending on the carrier surface. Also, offset resistance deteriorates, resulting in a decrease in image density under high temperature and high humidity conditions). On the other hand, when the softening point Tsp is too high, the compatibility with wax decreases, and the wax tends to fall off, which tends to cause contamination of carriers and the like, and a decrease in wrapping resistance.

Here, the softening point Tsp refers to the Koka type flow tester rC
FT-500 model (manufactured by Takasugi Seisakusho), the measurement conditions were a load of 20 kg/cm, and a nozzle diameter of 1 mm.

Nozzle length 1 mm, preheating at 80°C for 10 minutes, heating rate 6°C/min, sample amount 1cm @ (intrinsic specific gravity
When the height of the S-curve in the flow tester's plunger drop-temperature curve (softening flow curve) is h, h/2
The temperature at which

Furthermore, the glass transition point Tg of the specific polyester is
50-70°C is preferred. When the glass transition point Tg is too small, a decrease in image density is likely to occur. On the other hand, when the glass transition point Tg is too high, fixing performance deteriorates.

Here, the glass transition point Tg is measured using a differential scanning calorimeter "low-temperature DSCJ" (Rigaku Denki Co., Ltd.) by performing the following operations.

(1) Place 3 hg of a powdered sample in an aluminum pan and raise the temperature from 20°C to 100°C at a heating rate of 10°C/min.

(2) Leave at 100°C for 3 minutes, then cool to 20°C by air cooling.

(3) After that, measurement was performed at a heating rate of 10°C/min, and the extension line of the baseline below the glass transition point of the DSC thermogram in the glass transition region and the maximum between the rising part of the peak and the top of the peak were measured. The temperature at the intersection with the tangent line indicating the slope was defined as the glass transition point.

The electrostatic image developer of the present invention may contain a wax, a colorant, a charge control agent, and the like in addition to the binder resin made of the above-mentioned specific polyester.

As such a wax, waxes such as polyolefins, fatty acid esters, partially saponified fatty acid esters, higher alcohols, paraffin waxes, amide waxes, and mixtures thereof can be used.

Examples of the polyolefin include polypropylene,
Examples include resins such as polyethylene and polybutene.

Examples of the fatty acid ester include ethyl maleate, butyl maleate, methyl stearate, butyl stearate, cetyl palmitate, and ethylene glycol montanate.

Examples of the paraffin wax include natural paraffin, micro wax, and synthetic paraffin.

Examples of the amide wax include stearic acid amide, oleic acid amide, valmitic acid amide, lauric acid amide, behenic acid amide, methylene bis stearamide, and ethylene bis stearamide.

In the above waxes, JIS K 2235-19
It is preferable that the penetration degree defined by 80 is 4 or less. By using a wax having a penetration degree of 4 or less, it is possible to further prevent the occurrence of a filming phenomenon caused by the wax on the carrier, latent scratch carrier, developer carrier, etc.

Further, the melting point of the wax is preferably 60 to 160°C.

If the melting point is too high, the offset resistance will deteriorate, while if it is too low, the storage stability of the toner will deteriorate. The melting point is measured by filling a small glass tube with a small amount of sample, placing it in a sulfuric acid bath, heating it, observing the point at which it melts transparently, and measuring the temperature of the sulfuric acid bath at that point with a thermometer. Ta.

The blending ratio of such wax is preferably 1 to 20 parts by weight per 100 parts by weight of the binder resin. If the proportion of wax is too small, the toner's anti-offset properties and anti-wrapping properties tend to deteriorate, while if it is too large, huge wax aggregates are formed in the polyester, and even if they do not fall off, they contaminate the carrier, etc. It becomes easier to do.

Examples of colorants include carbon black, acetylene black, benzidine yellow, naphthol yellow,
Dyes or pigments such as hand yellow, rhodamine lake, phthalocyanine blue, alizarin lake, quinoline yellow, azo dyes, anthraquinone dyes, xanthine dyes, and methine dyes are used. The blending ratio is
It is preferably 1 to 20 parts by weight based on 100 parts by weight of the binder resin.

As charge control agents, metal complex salts of monoazo dyes, Zn sA's of salicylic acid, naphthoic acid, and guicarboxylic acid are used.
Metal complexes such as Co and Cr, quaternary ammonium salt compounds, nigrosine dyes, etc. are used.

As a method for producing the toner constituting the developer of the present invention,
For example, the above-mentioned specific polyester, wax, and other toner components added as necessary are mixed, melted and kneaded, then cooled, then crushed, and further classified to obtain a predetermined average particle size. obtain a toner with

Further, when forming a magnetic toner, magnetic particles such as iron, ferrite, magnetite, etc. are dispersed and contained in the toner particles.

In the present invention, the inorganic fine particles constituting the electrostatic image developer together with the toner are those treated with a nitrogen-containing substance.

Such a nitrogen-containing substance includes, for example, polysiloxane having an ammonium base, and inorganic fine particles treated with this compound have excellent positive chargeability and can prevent cleaning defects from occurring. Moreover, since the functional groups of polysiloxane and hydrophilic groups such as hydroxyl groups present on the surface of the inorganic fine particles are strongly bonded, it has excellent moisture resistance and durability, and is stable and unaffected by environmental conditions. The result is inorganic fine particles with positive triboelectric charging properties.

The dimethylpolysiloxane having an ammonium base is generally a dimethylsiloxane containing a structural unit represented by the following formula (A), for example, represented by the structural formula of formula (B).

Formula (A) R+ 5iO- R3 R, -N・-R3・xe R4 (wherein, R1 represents a hydrogen atom, a hydroxy group, an alkyl group, an aryl group, an alkoxy group, or , 2 represents a bonding group (for example, an alkylene group, an arylene group, an aralkylene group, -NH--NHCO- or any combination of these groups) or a simple bond. ,R3,
R4 and R6 each represent a hydrogen atom, an alkyl group or an aryl group, and X represents a halogen atom. R1～
Each group represented by Rs has a substituent and also includes Q. ) Formula (B) R1 (Here, R@ and R7 each represent a hydrogen atom, a hydroxy group, an alkyl group, an aryl group, or an alkoxy group, and these groups include those having a substituent.

R1~Rs, X are RI~R55X in the above formula (A)
It is similar to mSn each represents an integer of 1 or more. ) R3 Further, specific examples of R2N.-R3.xO include those represented by the following structural formula, but are not limited thereto.

(1) CH.

→CH2)7N・-CH,・CJe CH.

(2) CHI →CH, +r-N・-CH,・CI! QCH2 (3) CHI →CH Tsuji T-N ” -'-f C) (#rr CH3
” (J ”CH.

(4) CH.

1+CH2+7N・-1→CH2+-rT-CH3・C
JleCHI CsHs NI-÷CHO)3' CI”CsH@
N・Ha・(J” C2H40H −C3Hs−N@H−(117@C2H,−0H CsH= NIHt・Cl1e CH.

(9) -CIH, -NI H(CHsL・αθ(
10) CH.

C3Ha NHCIH-N" CHa 'C1"
CH.

-C,H@-NH-Co-N・Ha' C00CsH
s N・ HOCtHs C00CsHs CsHs -C Hs NIH-(IJ' CHI As a method for obtaining polysiloxanes having ammonium bases, there are two methods for obtaining polysiloxanes having ammonium bases: organohalogenated silanes having ammonium bases and organohalogenated silanes having no ammonium bases in particular. It can be obtained by a method in which a polysiloxane is introduced by copolymerization in the polymerization step, a part of a polysiloxane obtained by polymerization using an organohalogenated silane is modified with an organic group having an ammonium base, etc. Organoalkoxysilane may be used instead of organohalogenated silane. Some of the compounds are also available as commercial products.

Examples of inorganic fine particles used for surface treatment with polysiloxane having an ammonium base include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, chromium oxide, and Examples include fine particles of cerium, antimony dioxide, zirconium oxide, silicon carbide, and the like. It is preferable that the average particle size of the primary particles (particles separated into individual unit particles) of such inorganic fine particles is in the range of 3IIg to 27/l.

As the inorganic fine particles, silica fine particles can be particularly preferably used in order to improve fluidity.

As a method for treating the surface of inorganic fine particles with a nitrogen-containing substance such as the one described above, a known technique can be used. Specifically, for example, inorganic fine particles are added to a solution in which a nitrogen-containing substance such as the one described above is dissolved in a solvent. After dispersing the nitrogen-containing substance, remove the solvent by filtration or spray drying, and then harden by heating, or use a fluidizing bed device to dissolve a solution of the nitrogen-containing substance in the solvent as described in 1 above. A method can be used in which the film is cured by spray coating on fine particles and then heating and drying to remove the solvent.

The particle size of the positively chargeable inorganic fine particles whose surface has been treated with the above nitrogen-containing substance obtained in this way is 1
The average particle size of the secondary particles (particles separated into individual unit particles) is preferably within the range of 311μ to 21+, particularly 5μ to 500μ. Further, the BET specific surface area is preferably 20 to 500 m"/g. If the average particle size is too small or the BET specific surface area is too large, for example, when cleaning with a blade type cleaning device, inorganic Fine particles may easily slip through, resulting in poor cleaning.On the other hand, when the average particle size is too large or the BET specific surface area is too small, the fluidity of the developer decreases and developability deteriorates, resulting in poor image quality. Density may decrease or surface image unevenness may occur.

It is preferable that the inorganic fine particles treated with a nitrogen-containing substance be added to the toner from the outside and mixed therein so as to be attached to the surface of the toner particles.

The content of inorganic fine particles treated with a nitrogen-containing substance is preferably 0.1 to 5% by weight, particularly 0.1 to 2% by weight of the toner.
Weight percent is preferred. When the content ratio is too small, the fluidity of the developer may decrease, resulting in poor triboelectric charging properties of the toner, making it difficult to impart an appropriate amount of positive charge to the toner. Fog or stains on the back may occur. On the other hand, when the content ratio is excessive, some of the inorganic fine particles may exist in a free state from the toner particles, and as a result, the free inorganic fine particles may adhere to and transfer to the carrier particles, or may adhere to the inner wall of the developing device. , deposits on the developing sleeve, regulation blade, etc.
As a result, the triboelectric charging properties of the toner become poor at an early stage, making it difficult to apply an appropriate amount of positive charge to the toner, which may cause fogging or a decrease in image density.

In the present invention, when forming a two-component developer,
In addition to the toner and non-fine particles treated with a nitrogen-containing substance, a carrier is further used.

As such a carrier, magnetic particles, a resin-coated carrier formed by coating the surface of magnetic particles with a resin, etc. can be used.

The magnetic particles constituting the carrier include materials that are strongly magnetized in the direction of a magnetic field, such as iron, ferrite,
Examples include metals or alloys exhibiting ferromagnetism such as magnetite, iron, nickel, and cobalt, or compounds containing these elements.

As the resin for coating the resin-coated carrier, for example, styrene-acrylic copolymer, silicone resin, fluororesin, etc. can be suitably used.

The average particle size of the carrier is preferably 20 to 200 μm, particularly preferably 40 to 150 nm. When the average particle size is too small, a so-called carrier adhesion phenomenon occurs in which carrier adheres to the electrostatic latent image and forms a fixed image, and as a result, the image may become unclear.On the other hand, when the average particle size is too large, Sometimes image distortion may occur. Here, the average particle size (weight) of the carrier is "Microtrack" (
(manufactured by Nikkiso Co., Ltd.).

〔Example〕

Examples of the present invention will be specifically described below, but the present invention is not limited to these Examples.

Production of Polyester (1) Polyester for the Invention The dicarboxylic acids and dialcohols shown in Table 1 (Part 1) below were prepared using a thermometer, a stainless steel stirrer, a glass nitrogen gas introduction tube, and a flow-down condenser. Place the flask in a 4-hole round bottom flask with a capacity of 11, set this flask on a mantle heater, and introduce nitrogen gas from the nitrogen gas inlet tube to raise the temperature while maintaining an inert atmosphere inside the flask. , then O, (15 g of dibutyltin oxide was added and reacted while keeping the temperature at 200 ° C., and then a trivalent or higher polyvalent monomer shown in Table 1 (Part 1) below was added and further reacted. , each polyester was obtained.

Acid value (AV) and hydroxyl value (OHV) of each polyester
, the sum of both (OHV+AV), the value of the ratio OHV/AV,
Softening point T Sps Glass transition point Tg is as shown in Table 1 (Part 2) below.

(2) Comparative Polyester 1 229 g of terephthalic acid and polyoxypropylene (2,
2) Comparison of 211 g of -2,2-bis(4-hydroxyphenyl)propane and 82 g of pentaerythritol mixed and reacted at 200°C, resulting in a chloroform insoluble content of 15% by weight and a softening point Tsp of 135°C. Polyester 1 was produced.

(3) Comparative polyester 2 Polyoxypropylene (2,2)-2,2-bis(4-
490 g of polyoxyethylene (2>-2,2-bis(4-hydroxyphenyl)propane), 224 g of terephthalic acid, 48 g of n-dodecenylsuccinic anhydride, and 1,6-hexane. 12 g of diol, 10 g of fumaric acid, and 0.8 g of diisopropyl orthotitanate (esterification catalyst),
Place it in a round bottom flask with a capacity of 11 equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube, and a flow-down condenser, set this flask on a mantle heater, and introduce nitrogen gas from the nitrogen gas inlet tube. The temperature was raised to 230° C. while maintaining the inside of the flask in an inert atmosphere, and the reaction was carried out under stirring.

When the water produced by the reaction stopped flowing out, the acid value was measured and found to be 1.5.

Furthermore, 35 g of 1,2,4-benzenetricarboxylic acid anhydride was added and reacted for about 8 hours until the acid value reached 1.
2, the reaction was terminated and comparative polyester 2 was produced. This polyester was a pale yellow solid with a softening point Tsp of 130°C.

Production of toner> (1) Toner for the present invention After mixing the toner materials shown in Table 2 using a V-type pre-mix, melt-kneading using two rolls, cooling, and then coarsely pulverizing using a hammer mill. The particles were further finely pulverized using a jet mill, and then classified using an air classifier to obtain an average particle size of 11. On toners 1 to 6 were produced.

(2) Toner for comparison Comparative toners 1 and 2 were produced in the same manner as the toner for the present invention described above using the toner materials shown in Table 2 below.

Production of Inorganic Fine Particles> (1) Inorganic Fine Particles 1 (For the Present Invention) A treatment liquid was prepared by dissolving a polysiloxane having an ammonium base represented by the following formula (2) as a constituent unit in xylene.

Expression ``Child 1''. The inorganic fine particles 1 have an average primary particle diameter of 12iμ and a specific surface area of 115IT1 by BET method.
It was 2/g.

(2) Inorganic fine particles 2 (for the present invention) A treatment liquid was prepared by dissolving a polysiloxane having an ammonium base represented by the following formula (2) as a constituent unit in xylene.

(CHJa HsCN・-C1],・α・CHs (x is an integer) Formula ■Next, silica fine particles “Aerosil 200J (manufactured by Nippon Aerosil Co., Ltd.) are placed in a mixer, and the above polysiloxane is added to the silica fine particles. After spraying at a ratio of 5% by weight, these were placed in a flask, and the solvent xylene was removed at a temperature of 200°C for 5 hours while stirring, thereby obtaining surface-treated inorganic fine particles. "Inorganic fine particles 1: Ht N" CH!・α
・CHri (y is an integer) Next, silica fine particles "Aerosil 300J (manufactured by Nippon Aerosil Co., Ltd.) were placed in a mixer, and the above polysiloxane was sprayed at a ratio of 17% by weight to the silica fine particles. Other than that, surface-treated inorganic fine particles were obtained by performing the same treatment as in the production of inorganic fine particles 1. These are referred to as "inorganic fine particles 2." The inorganic fine particles 2 had an average primary particle diameter of 7 mm and a specific surface area of 126 m''/g by the BET method.

(3) Inorganic fine particles 3 (for the present invention) A treatment liquid was prepared by dissolving a polysiloxane having an ammonium base represented by the following formula (2) as a constituent unit in xylene.

(CHJs H,C-Nφ-C+tH*s'(J.

CHs (z is an integer) Next, silica fine particles "Aerosil 200J (manufactured by Nihon Aerosil Co., Ltd.) were placed in a mixer, and the above polysiloxane was sprayed at a ratio of 10% by weight to the silica fine particles. Surface-treated inorganic fine particles were obtained by processing in the same manner as in the production of inorganic fine particles 1. These are referred to as "inorganic fine particles 3." The inorganic fine particles 3 have an average primary particle diameter of 121 μm and a specific surface area of 93 m”/g by the BET method.
Met.

(4) Comparative Inorganic Fine Particles 1 Negatively chargeable silica fine particles "Aerosil R-972J (manufactured by Nippon Aerosil Co., Ltd.) are used as Comparative Inorganic Fine Particles 1.

(1) Carrier 1 Vinylidene fluoride-tetrafluoroethylene copolymer rVT-
100'' (copolymerization molar ratio=80:20, intrinsic viscosity=
0.95 dl/g, manufactured by Daikin Industries, Ltd. > 6 g, and 6 g of methyl methacrylate copolymer "Acrivet MFJ (manufactured by Mitsubishi Raylan) were mixed in a mixed solvent of acetone and methyl ethyl ketone (mixed volume ratio - 1:1) 50 (A coating solution was prepared by dissolving it in LD. Using a fluidization ped device, the coating solution was applied to 1 kg of magnetic particles made of spherical copper-zinc ferrite (manufactured by Nippon Tetsuko Kogyo Co., Ltd.): Coating treatment The carrier 1 was further heat-treated at 200°C for 5 hours, and the aggregates were sieved to produce a carrier 1 having a resin coating layer with a thickness of about 2I.The average particle size of this carrier 1 was There was 82μ of snow.

Preparation of developer> Using the combinations of inorganic fine particles, toner and carrier shown in Table 3 below, first, by adding the inorganic fine particles to the toner and mixing them with a Henschel mixer,
Inorganic fine particles are attached to and retained on the surface of toner particles,
Further, a carrier was mixed with these using a V-type mixer to produce each developer.

Actual photocopying test> An electrophotographic copying machine "U-Bix 155" equipped with a photoreceptor for forming a negative electrostatic latent image using each of the above-mentioned developers was used.
0MRJ (manufactured by Konica TM) aiti machine 1:, kt
), normal temperature? A photocopying test was conducted in which copied images were continuously formed 50,000 times under environmental conditions of M (temperature 20° C., relative humidity 60%), and the following items were evaluated.

(1) Use Capri "Sakura Densitometer" (manufactured by Konica@) to measure and determine the relative density of the white background (portion corresponding to the white background with original density of 0.0) in the copied image. In addition,
The white background reflection density was set to 0.0. The evaluation is based on the relative concentration of 0.
If it is less than [1];, it is "○J, 0.[1]; if it is more than 0.
If it is less than 0.03, mark it as “△J”; if it is greater than or equal to 0.03, mark it as “×”
And so.

(2) Image density For the copied image after 50,000 times, the maximum relative density of the image area in the copied image was measured using "Sakura Densitometer" (manufactured by Konica ■) and determined. The practical level is such that the highest value is 1.0 or more.

(3) Toner scattering Visually observe the inside of the copying machine and the copied image. If there is almost no toner scattering and it is in good condition, mark it as "○." If there is some toner scattering, but it is at a practical level, mark it as "△."
", and the case where there is a lot of toner scattering and S is a problem in practical use is designated as rXJ.

(4) Contamination on the back side of the leading edge of the transfer paper The leading edge area of the back side of the transfer paper that had passed through the fixing device was visually observed and evaluated. "O" means that there is almost no dirt on the back surface and it is in good condition; "△" means that there is some dirt on the back surface but it is at a practical level; "rXJ" means that there is a lot of dirt on the back surface and it is a practical problem. did.

The above results are shown in Table 4 below.

As can be understood from the results of the above examples, the electrostatic image developer of the present invention does not generate fine powder due to the destruction of toner particles, and exhibits stable triboelectric charging properties over a long period of time. Therefore, a fog-free image with high image density can be stably formed many times without toner scattering and without staining the back surface of the leading edge of the transfer paper. Furthermore, the fixing properties and anti-offset properties are also good.

On the other hand, according to Comparative Developer 1, when an image is formed many times, the toner particles are destroyed by mechanical external forces such as agitation received in the developing device and fine powder is generated. The triboelectricity of the toner and carrier decreases, causing toner scattering and fogging. Also,
According to Comparative Developer 2, because it uses negatively chargeable silica fine particles, the toner's triboelectricity rises poorly even when a fluororesin-coated carrier with strong negative chargeability is used, and images are formed many times. As a result, toner scatters, and even slight changes in the surface state of the carrier cause the triboelectric charging properties to become unstable, resulting in fogging.

Furthermore, when the zero-copy test was continued up to 100,000 times for the developers 1 to 6 of the present invention, there was no occurrence of poor cleaning or scratches on the photoreceptor.

〔Effect of the invention〕

According to the first aspect of the invention, since a specific polyester is used as the binder resin of the toner, destruction of the toner particles can be effectively prevented even when the toner is subjected to large mechanical stress. Therefore, the characteristics of the inorganic fine particles treated with a nitrogen-containing substance are fully exhibited, and stable triboelectric charging properties are exhibited over a long period of time, resulting in no fogging and no toner scattering or staining of the back surface of the leading edge of the transfer paper. A good image with high density can be formed.

In addition, when the nitrogen-containing substance is a polysiloxane polymer having an ammonium base, it has a high cleaning effect even on a soft organic photoreceptor, and it is possible to achieve a long life of the photoreceptor without damaging the photoreceptor. can.

In addition, by particularly using benzenetricarboxylic acids as the trivalent or higher polyvalent monomer in component (2), more stable triboelectric charging properties can be imparted to the toner.
Furthermore, fixing properties and hot offset resistance are improved.

Further, according to the invention of claim 2, it is possible to obtain a highly reliable copy image with high image density, which can be stably obtained in this state, and which is free from fog, and which has excellent fixing properties, anti-offset properties, and A copy image that is resistant to curling can be obtained.

Claims (2)

[Claims] (1) An electrostatic image developer comprising a toner and inorganic fine particles treated with a nitrogen-containing substance, in which the toner condenses a monomer composition containing the following components [1] to [3]. An electrostatic image developer characterized by containing a polyester obtained by polymerization reaction as a binder resin. Ingredients [1]
; Trivalent or higher polyvalent monomer component [2]; Aromatic dicarboxylic acid component [3]; Aliphatic dialcohol (2) Acid value (AV) and hydroxyl value (OHV) of polyester
) is 30 or more and 80 or less.