JP3376191B2 - Toner for developing electrostatic images - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art In recent years, demands for high definition and high image quality of electrophotography as well as high reliability and high durability of image forming methods have been increasing in the market. In the technical field, attempts have been made mainly to reduce the particle size of the toner to achieve high-quality color for high definition and high image quality. However, when the particle size becomes fine, the surface area per unit weight decreases. There is a tendency for the toner charge amount to increase and the toner charge amount to increase, and there is a concern that the image density will be low and the durability will deteriorate. In addition, since the charge amount of the toner is large, the adhesion between the toners is strong, the fluidity is lowered, and problems occur in the stability of toner replenishment and tribo application to the replenishment toner.

Further, in the color image forming method, since the toner does not contain a conductive substance such as a magnetic substance, there is no portion for leaking charge, and the charge amount generally tends to be large. This tendency is more remarkable when a polyester binder having high charging performance is used.

Particularly, in the color image forming method, 1
Since four color toners have to be developed in one sheet of image, when an image is formed by contact transfer using a rigid member as a transfer member or the like, in particular, voids in the image or toner particles on non-image areas Scattering is likely to occur and a beautiful pictorial image cannot be obtained.

Particularly in the color image forming method, the following characteristics are strongly desired.

(1) The fixed toner needs to be in a state of almost completely melting so that the shape of the toner particles cannot be discriminated so as not to diffusely reflect light and prevent color reproduction. is there.

(2) It must be a colored toner having transparency that does not interfere with the toner layers of different tones underlying the toner layer.

(3) Each of the constituent toners must have well-balanced hue and spectral reflection characteristics and sufficient saturation.

(4) The method of developing and transferring each toner must be highly reliable with no voids or scattering.

(5) In order to obtain a full-color image, multiple transfer must be performed, so that the constituent members must have high durability.

From this point of view, many studies have been conducted on the binder resin in the toner, but a toner satisfying all the above characteristics has not been developed yet. Today, polyester resins are often used as color binder resins in this technical field, but toners made of polyester resins are generally easily affected by temperature and humidity, and have excessive charge and high humidity under low humidity. There is an urgent need to develop a color toner and an image forming method having a stable charge amount even in a wide range of environments due to the problem that the charge amount is insufficient.

On the other hand, one of the means for solving these problems is to add various chemical substances to the toner.
In particular, various fine powders are widely added to improve the chargeability and fluidity of the toner for the purpose of improving various image characteristics such as resolution, density uniformity, and fog. There is.

Titanium oxide fine particles are mentioned as one of the widely used fine powders added to improve various properties of the toner, and particularly surface treated with silicone oil, silane coupling agent or silicone varnish. Tako has a high degree of hydrophobicity and is preferably used.

To date, examples of toners containing hydrophobized titanium oxide include JP-B-53-39307, JP-A-60-112052, and JP-A-60-23884.
No. 9, JP-A No. 64-8854, and JP-A No. 2-1.
09058, JP 4-204750, JP 5-19528, JP 5-188633, JP 5-119517, and JP 5-28.
9391, JP-A-6-11886, JP-A-6-11887, and JP-A-6-19186 propose toners containing surface-treated titanium oxide. Although the electrophotographic characteristics are certainly improved, the uniformity of hydrophobicity is insufficient and sufficient triboelectrification cannot be obtained under high humidity or left for a long time, resulting in a decrease in image density and fogging. Like

The reason why the hydrophobicity of titanium oxide becomes nonuniform as described above is described in Prog. Surface Me
mbrane Science. 11,181 (197)
6), Discuss Faraday Societ
y. , 52, 264 (1971), since there are reactive hydroxyl groups having different properties on the surface of titanium oxide (see FIG. 1), the reactivity with the treating agent is different and the hydrophobicity is not uniform. Alternatively, the water that is hydrogen-bonded or physically adsorbed to the hydroxyl group on the surface of titanium oxide has poor compatibility with a surface treatment agent such as silicone oil, a silane coupling agent, or a silicone varnish, and the surface hydrophobic treatment may not be uniform. Can be considered.

A method of dehydrating the hydroxyl groups on the surface of titanium oxide particles by heat treatment to make them hydrophobic is as follows.
It is proposed in JP-A-4-340971 and JP-A-4-340972. For this, titanium oxide of 200-600
Titanium oxide has been proposed which is heat-treated at ° C to dehydrate and condense hydroxyl groups on the surface of titanium oxide to make it hydrophobic, thereby achieving charge stability, environmental stability and uniformity of the externally added toner. However, in the case of titanium oxide, when dehydration condensation is performed in the temperature range, not only the dehydration treatment may not be completely performed, but also water addition (rehydration) reaction occurs again in a high temperature and high humidity environment, for example. However, this reaction has been a cause of adversely affecting the charge stability, environmental stability, long-term storage stability and uniformity of the externally added toner.

Further, when the above titanium oxide was applied to a full color toner, it was not particularly satisfactorily satisfactory.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner which solves the above problems.

That is, an object of the present invention is to provide a toner which can obtain sufficient fluidity, developability and transferability even under high humidity.

A further object of the present invention is to provide a toner which is not easily affected by humidity and maintains sufficient developability even when left standing for a long time.

[0021]

According to the present invention, the surface of titanium oxide is not organically treated with an organic hydrophobizing agent ,
It relates toner for developing electrostatic images which is characterized that you methanol hydrophobizing degree is 35% or more of the titanium oxide particles are externally added, very excellent fluidity under high humidity, developability, transferability It is possible to obtain a toner that has storage stability.

[0022]

DETAILED DESCRIPTION OF THE INVENTION The constitution of the present invention will be described in detail below.

The toner used in the present invention will be described in detail below.

The toner used in the present invention contains titanium oxide whose surface has been hydrophobized without using an organic hydrophobizing agent by subjecting it to redox treatment or heat treatment. It gives effective fluidity and stable chargeability, and it is possible to stably obtain images with high density without fogging, and because it has excellent moisture resistance, it can be used under high humidity.
Good developability and transferability are obtained even after being left for a long time, and its durability is also excellent.

That is, the toner used in the present invention contains titanium oxide particles having a methanol hydrophobicity of 35% or more.
Characterized that you have been externally added, preferably methanol
When the degree of hydrophobicity is 45% or more, more preferably 55% or more, good developability, durability, storage stability, moisture resistance, developability under high humidity, transferability, and storage stability can be obtained.

The degree of hydrophobicity of methanol used in the present invention can be measured by using methanol titration. That is, when a sample is floated on water and methanol is dropped, the sample having low hydrophobicity starts to get wet and the sample starts to sink. Then, the addition of methanol is continued, and finally the highly hydrophobic sample becomes wet, and all the sample sinks in the liquid. At this point, the methanol hydrophobicity is defined.

Further, since the titanium oxide used in the present invention is not surface-treated with an organic treating agent or the like, the amount of organic substances deposited on the surface is extremely small, the silicon content is 0.1% by mass or less, and the carbon content is It is 0.5 mass% or less.

In the present invention, the content of silicon and the content of carbon in titanium oxide are X-ray fluorescence analyzer SYSTEM308.
0 (manufactured by Rigaku Denki Kogyo Co., Ltd.) is used and JIS K-0
In accordance with 119 "General rules for fluorescent X-ray analysis", fluorescent X-ray analysis was performed.

As the hydrophobizing treatment carried out in the present invention, a method using an inorganic redox agent and dehydration condensation hydrophobizing by heat treatment are preferably used.

The heat treatment temperature in the present invention is preferably 600 ° C. or more and 1800 ° C. or less, more preferably 600 ° C. or more and 1500 ° C. or less, and particularly preferably 6
It is 50 ° C. or higher and 1000 ° C. or lower.

The heat treatment method is not particularly limited as long as it can control the heating in the above temperature range, but preferably has a structure capable of passing an inert gas such as nitrogen or helium. It is preferable or preferable to have a structure capable of heating under reduced pressure.

This heat treatment is generated in a step of cooling after heating, but preferably the same step is repeated twice or three times to stabilize the bond between titanium and oxygen after the dehydration condensation reaction. Is preferred.

Further, after the heat treatment, a crushing treatment by a known crusher is performed to reduce aggregates of titanium oxide, reduce the bulk density, and improve the fluidity of the externally added toner. It is preferable above. As a method of crushing,
Jet mill, impact crusher, pin mill, hammer mill,
There are crushers such as sand mills, grain mills, basket mills, ball mills, sand grinders, and visco mills that use media.

The titanium oxide before hydrophobization used in the present invention is obtained by a sulfuric acid method, a chlorine method or a low temperature oxidation (thermal decomposition or hydrolysis) of a volatile titanium compound such as titanium alkoxide, titanium halide or titanium acetylacetonate. Titanium oxide is used, and the crystal type is anatase type,
Any of rutile type, mixed crystal type of these, and amorphous type can be used.

The average particle size of the titanium oxide before hydrophobization at this time is preferably less than 0.1 μm,
When the thickness is 0.1 μm or more, titanium oxide after heat treatment cannot obtain fluidity and uniform charging property, resulting in poor developability and durability. Here, the average particle diameter is obtained by actually measuring the particle diameter of 400 arbitrary primary particles with a transmission electron microscope having a magnification of 100,000 and calculating the number average diameter.

As for other physical properties, it is preferable that the specific surface area by the BET one-point method is 15 m ² / g or more,
It is more preferably 20 m ² / g, particularly preferably 2
It is 5 m ² / g or more. If the specific surface area is less than 15 m ² / g, the fluidity and releasability will be poor, and the developability and transferability will be adversely affected.

Further, it is preferable that a bulk density of 0.5 g / cm ³ or less, preferably further is 0.45 g / cm ³ or less, particularly preferably 0.4 g / cm ³
It is the following. When the bulk density exceeds 0.5 g / cm ³ , the fluidity and the charging uniformity become poor, the developing property becomes non-uniform, and the density unevenness occurs.

The absolute value of the charge amount due to blow-off is preferably 100 mC / kg or less, more preferably 50 mC / kg or less. 100 mC
When it exceeds / kg, uneven charging property or excessive charging tends to occur, and image density unevenness or fogging tends to occur.

The content of titanium oxide of the present invention is the same as that of toner 1.
The amount is preferably 0.2 to 5.0 parts by mass, more preferably 0.4 to 3.5 parts by mass with respect to 00 parts by mass. If it is less than 0.2 parts by mass, the effect of addition will be small, and if it exceeds 5.0 parts by mass, filming on the photosensitive drum or cleaning failure will easily occur.

In the present invention, the specific surface area is a flow type automatic specific surface area measuring apparatus Micromeritics Flowsorb I
I 2300 type (manufactured by Shimadzu Corp.) is used, and 0.2 g of the sample is subjected to degassing treatment at 70 ° C. for 30 minutes using a mixed gas flow of 30% by volume of nitrogen and 70% by volume of helium.

The bulk density is determined according to JIS K-5101.

The blow-off charge amount is measured using a blow-off powder charge measuring device TB-200 (manufactured by Toshiba Chemical Co., Ltd.). Measurement sample and carrier (TEFV
200/300 Reduced iron powder manufactured by Nippon Iron Powder Co., Ltd.) is stored for 12 hours or more in an environment of 23 ° C. and 60% RH.

Measurement sample (A): Carrier (B) = 0.1
The sample and the carrier were weighed at a ratio of 5 g: 29.85 g, placed in a sample mixing container (50 cm ³ cylindrical bottle made of polypropylene) and sealed tightly, and then shaken for 5 minutes with a mix rotor (MR-2 type manufactured by Inei Seieido Co., Ltd.) Then, let stand for 5 minutes.
About 0.2 g of the mixed sample in the mixing container is precisely weighed (weighing value is C), put in a Faraday gauge of a blow-off measuring device, and measured under the following conditions.

Blow pressure: 9.8 × 10 ^-2 MPa Blow time: 10 s Blow gas: Nitrogen measuring environment: 23 ° C., 60% RH Faraday gauge filter: sus316 400 mesh The charge amount is derived from the following formula.

Charge amount = measured charge amount Q / [C × A / (A +
B)] mC / kg

The following binder resins can be used as the binder resin of the toner in the present invention.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene and their substitution products; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene. Copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Preferred binder substances include styrene copolymers, polyester resins and epoxy resins, and particularly polyester resins and epoxy resins.

Examples of the comonomer for the styrene monomer of the styrene type copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, acrylic acid-
2-Diethylhexyl, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, dicarboxylic acids having a double bond such as acrylamide, and the like; Vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate and the like; eg ethylene, propylene,
Ethylenic olefins such as butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl monomers such as Are used alone or in combination of two or more.

The styrene polymer or styrene copolymer may be crosslinked or may be a mixed resin.

As the crosslinking agent for the binder resin, a compound mainly having two or more polymerizable double bonds may be used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and 3
A compound having at least one vinyl group; is used alone or as a mixture.

Since the titanium oxide of the present invention has excellent moisture resistance, it is preferably used for a toner containing a polyester resin, an epoxy resin, or a polyol resin, which is easily affected by humidity in charging property. That is, the adverse effects of these resins can be compensated for, and good developability under high humidity can be maintained. Polyester resins, polyol resins, and epoxy resins are preferably used because they have excellent fixability, and particularly in full-color toner, they have excellent color mixing properties. That is,
When the titanium oxide of the present invention is used with a toner containing a polyester resin, a polyol resin, and an epoxy resin as a binder resin component, fixability, developability under high humidity, and leaving stability over time can be obtained. Further, in the color toner, since excellent transferability and color mixing property are obtained, a beautiful pictorial image can be obtained.

For the above reasons, the styrene resin,
It is also preferably used in a mixture of a polyester resin, a polyol resin, an epoxy resin, a graft copolymer of these resins, a block copolymer and a mixture thereof.

The epoxy resin and polyol resin used in the present invention are as follows.

For example, skeleton bisphenol A
Type, halogenated bisphenol A type, biphenyl type, saligenin type, sulfone type, long chain bisphenol type, resorcin type, bisphenol F type, tetrahydroxyphenylethane type, novolac type, alcohol type, polyglycol type, polyol type, glycerin tri-type Ether type, polyolefin type, epoxidized soybean oil, alicyclic type and the like are used, and bisphenol type is preferably used. In addition to these, those reacted with a curing agent, those reacted with a compound having an active hydrogen at the terminal epoxy group, those reacted with phenol / polyphenols, amines / polyamines Those reacted, those reacted with carboxylic acid / polybasic acid / acid anhydride / ester derivative / lactone, those reacted with polyamide, and those reacted with an oligomer having a carboxylic acid group are preferably used. Further, those obtained by reacting a hydroxyl group with a carboxylic acid / anhydride / lactone / lactam are particularly preferably used.

Examples of the active hydrogen-containing compound include the following. Phenols include phenol, cresol, isopropylphenol, aminophenol, nonylphenol, dodecylphenol, xylenol, p-cumylphenol, and the like, and divalent phenols include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, and the like. Can be mentioned. As the carboxylic acid, acetic acid, propionic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, acrylic acid, oleic acid, margaric acid,
Examples thereof include araginic acid, linoleic acid and linolenic acid.
Examples of the ester derivative include alkyl esters of the above carboxylic acids, of which lower alkyl esters are preferable, and methyl ester and ethyl ester are particularly preferable. As lactones, β-propiolactone, δ-valerolactone, ε-caprolactone, γ
-Butyrolactone, β-butyrolactone, γ-valerolactone and the like. As amine, methylamine,
Ethylamine, propylamine, isopropylamine,
Examples include butylamine, amylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, laurylamine, stearylamine and the like.

The composition of the polyester resin used in the present invention is as follows.

Examples of the dihydric alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol and 1,5-pentanediol. 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-
Hexanediol, hydrogenated bisphenol A, bisphenol represented by the formula (A) and derivatives thereof;

[0058]

[Chemical 1]

(Wherein R is an ethylene or propylene group, x and y are each an integer of 0 or more, and
The average value of x + y is 0-10. )

Further, diols represented by the formula (B):

[0061]

[Chemical 2]

(In the formula, R ′ is —CH ₂ CH ₂ — or

[0063]

[Chemical 3] Where x ′ and y ′ are integers greater than or equal to 0, and x ′
The average value of + y 'is 0 to 10. ) Is mentioned.

As the divalent acid component, for example, phthalic acid,
Benzenedicarboxylic acids such as terephthalic acid, isophthalic acid and phthalic anhydride, or their anhydrides, lower alkyl esters; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or their anhydrides, lower alkyl esters; n- Alkenyl succinic acids such as dodecenyl succinic acid, n-dodecyl succinic acid or alkyl succinic acids, or their anhydrides, lower alkyl esters; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid or their anhydrides, lower Examples thereof include dicarboxylic acids such as alkyl ester; and derivatives thereof.

Further, it is preferable to use a trivalent or higher valent alcohol component which also functions as a crosslinking component and a trivalent or higher valent acid component together in order to improve durability.

The trihydric or higher polyhydric alcohol component is
For example, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,
3,5-trihydroxybenzene etc. are mentioned.

Examples of the trivalent or higher polyvalent carboxylic acid component in the present invention include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,
2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,
5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-
Octane tetracarboxylic acid, empol trimer acid, and their anhydrides, lower alkyl esters;

[0068]

[Chemical 4]

(In the formula, X is an alkylene group having 5 to 30 carbon atoms or an alkenylene group having at least one side chain having 3 or more carbon atoms), etc., and their anhydrides and lower alkyl esters. And polyvalent carboxylic acids and derivatives thereof.

The alcohol component used in the present invention is 40 to 60 mol%, preferably 45 to 55 mol.
%, 60-40 mol% as an acid component, preferably 5
It is preferably 5 to 45 mol%.

It is also preferable that the trivalent or higher polyvalent component accounts for 1 to 60 mol% of all components.

From the viewpoint of developability, fixability, durability and cleaning property, a styrene copolymer, a polyester resin, a polyol resin, an epoxy resin, a block copolymer thereof, a graft copolymer thereof or a resin thereof is used. Mixtures are preferred.

The styrene resin and the mixture with the styrene resin preferably have a peak in the region of 10 ⁵ or more in the molecular weight distribution measured by GPC, and further in the region of 3 × 10 ^{3 to} 5 × 10 ^4. It is preferable to have a peak in terms of fixability and durability.

Such a resin component can be obtained, for example, by the following method.

By applying solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, block copolymerization, grafting, etc., a polymer (L) having a main peak in the region of molecular weight of 3 × 10 ^{3 to} 5 × 10 ⁴ is obtained. A polymer having a main peak in the region of 10 ⁵ or more or a polymer (H) containing a gel component is formed. These components can be partially or completely cut during melt-kneading, and become THF-soluble components to be measured by GPC as components in a region of 10 ⁵ or more.

As a particularly preferable method, the polymer (L) is used.
Alternatively, the polymer (H) is formed by solution polymerization, and at the end of the polymerization, the other is blended in a solvent, the other polymer is polymerized in the presence of one polymer, and the polymer (H) is suspended. A method of forming by polymerization and polymerizing the polymer (L) by solution polymerization in the presence of this polymer, a method of blending the polymer (H) in a solvent at the end of the solution polymerization, and the presence of the polymer (L) Then, there is a method in which the polymer (H) can be polymerized by suspension polymerization. By using these methods, a polymer in which a low molecular weight component and a high molecular weight component are uniformly mixed can be obtained.

As the binder resin for the toner used in the pressure fixing system, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-
Examples thereof include acrylic acid ester copolymers, higher fatty acids, polyamide resins, and polyester resins. These can be used alone or as a mixture.

When a styrene copolymer is used as the binder resin, the following toners are preferable in order to obtain good fixing property, blocking resistance and developing property.

In the molecular weight distribution of the toner by GPC (gel permeation chromatography), 3 × 10
Area of ^{3 to} 5 × 10 ⁴ , preferably 3 × 10 ^{3 to} 3 × 1
The presence of at least one peak (P ₁ ) in the region 0 ⁴ and particularly preferably in the region 5 × 10 ³ to 2 × 10 ⁴ makes it possible to obtain good fixability, developability and blocking resistance. . If it is less than 3 × 10 ³ , good blocking resistance cannot be obtained, and if it exceeds 5 × 10 ⁴ , good fixing property cannot be obtained. The 10 ⁵ or more regions, preferably at least one peak (P ₂₎ is present in a region of ^{3 × 10 5 ~5 × 10 6} , 3 × 10 5 ~2 × 10 6 regions 10 ⁵ or more regions of the It is particularly preferable to have the maximum peak at 1, and good high temperature offset resistance, blocking resistance, and developability can be obtained. The higher this peak molecular weight is, the stronger the high temperature offset becomes. However, when there is a region peak of 5 × 10 ⁶ or more, there is no problem with a heat roll that can apply pressure, but when pressure is not applied, The elasticity becomes large and the fixability is affected. Therefore, in the heat fixing with a relatively low pressure used in a medium to low speed machine, there is a peak in the region of 3 × 10 ⁵ to 2 × 10 ⁶ , and it is preferable that this is the maximum peak in the region of 10 ⁵ or more.

The component in the region of 10 ⁵ or less is 50% or more, preferably 60 to 90%, particularly preferably 65 to 8%.
5%. Within this range, good fixability and offset resistance can be obtained. When it is less than 50%, not only is sufficient fixing property not obtained, but also the pulverizability becomes poor.
If it exceeds 90%, the offset resistance,
It tends to be weak against blocking resistance.

When a polyester resin, an epoxy resin, or a polyol resin is used, the toner has a GPC molecular weight distribution of 3 × 10 ³ to 2 × 10 ⁴ , preferably 4 × 10 ^{3 to} 1.7 × 10. ⁴ areas, particularly preferably it is preferred that the main peak is present in the region of ^{5 × 10 3 ~1.5 × 10 4} . When used for a magnetic toner, it is preferable that at least one peak or shoulder exists in a region of 1.5 × 10 ⁴ or more, or 5% or more of a region of 5 × 10 ⁴ or more.

When the molecular weight distribution is as described above, good developability, blocking resistance, fixing property and offset resistance can be obtained.

When the main peak is less than 3 × 10 ³ , blocking resistance and developability are likely to be lowered.
When the main peak exceeds 2.0 × 10 ⁴ , good fixability cannot be obtained. Good offset resistance is obtained when peaks and shoulders are present in the area of 1.5 × 10 ⁴ or more, when the area of 5 × 10 ⁴ or more is 5% or more, and when Mw / Mn is 10 or more. It becomes possible to obtain.

The binder resin used in the toner of the present invention preferably has a glass transition point (Tg) of 50 to 70 ° C. Since the effect of the toner of the present invention can be improved by the heat history step, when the Tg is less than 50 ° C., blocking occurs during the step. Also, Tg is 7
If the temperature exceeds 0 ° C., the fixability will deteriorate.

In the present invention, the molecular weight distribution of the chromatogram of the toner by GPC is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40 ° C., and THF (tetrahydrofuran) as a solvent was flown through the column at this temperature at a flow rate of 1 ml / min, and about 100 μl of a THF sample solution was injected. taking measurement. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value and the count number of the calibration curve prepared from several kinds of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, one having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko KK is used, and at least 1
It is suitable to use a standard polystyrene sample of about 0 points. An RI (refractive index) detector is used as the detector.
As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns, for example, Shodex GPC KF-801, 802, 80 manufactured by Showa Denko KK
3,804,805,806,807,800P combination and TOSgel G1000H (H manufactured by Tosoh Corporation
_XL ), G2000H (H _XL ), G3000H (H _XL ),
G4000H (H _XL ), G5000H (H _XL ), G60
00H (H _XL ), G7000H (H _XL ), TSKgua
A combination of rdcolumns can be mentioned.

A sample is prepared as follows.

The sample is put in THF, left for several hours, shaken well and mixed well with THF (until the coalescence of the sample disappears), and left still for 12 hours or more. At this time T
The time of leaving in HF should be 24 hours or more.
Then sample processing filter (pore size 0.45
.About.0.5 .mu.m, for example, Mysholydisc H-25
-5 manufactured by Tosoh Co., Ltd., available from Ekikurodisc 25CR Gelman Science Japan Co., Ltd.) are used as GPC samples. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

The glass transition point is measured by ASTM D
3418-82. DS used in the present invention
The C curve is the DS measured when the temperature is raised at a temperature rate of 10 ° C./min after the temperature is raised and lowered once to take a previous history.
C curve is used. The definition is defined as follows.

Glass transition point (Tg) The temperature at the intersection of the DSC curve and the line connecting the midpoints of the baselines before and after the specific heat change appears in the DSC curve during temperature rise.

Further, from the viewpoint of improving the releasability from the fixing member during fixing and the fixing property, it is also preferable to include the following waxes in the toner.

Paraffin wax and its derivatives, montan wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, etc. Includes block copolymers and graft modified products with vinyl monomers. In addition, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and its derivatives, vegetable waxes, animal waxes, mineral waxes, petrolactam and the like can be used.

In the present invention, rapid and uniform chargeability is required, and the above-mentioned ones are preferable from the viewpoint of developability.
Among them, the wax preferably used is a low molecular weight polyolefin obtained by radically polymerizing an olefin under high pressure or using a Ziegler catalyst and a by-product at this time, a low molecular weight polyolefin obtained by thermally decomposing a high molecular weight polyolefin, Hydrocarbon distillation residue obtained by using a catalyst from a synthesis gas consisting of carbon monoxide and hydrogen,
Alternatively, a wax obtained from a synthetic hydrocarbon obtained by hydrogenating these is used, and an antioxidant may be added. Alternatively, alcohol, acid amide,
Esters or montan derivatives. Further, it is also preferable that impurities such as fatty acids have been removed in advance.

The colorant that can be used in the toner of the present invention includes any appropriate pigment or dye. As the colorant of the toner, for example, carbon black as a pigment,
There are aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, red iron oxide, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary and sufficient for maintaining the optical density of the fixed image, and preferably the resin 1
The amount added is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass with respect to 00 parts by mass.

Further, a dye is used for the same purpose. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, and these are preferably resin 1
The amount added is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 10 parts by mass with respect to 00 parts by mass.

The following organic pigments or dyes are preferably used as the colorants used in the cyan, magenta and yellow toners of the present invention.

Examples of the pigment include disazo yellow pigments, insoluble azo pigments, copper phthaloanine pigments, and dyes include basic dyes and oil-soluble dyes.

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. 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. Mordant Blue 7 and the like can be mentioned.

As the pigment, naphthol yellow S, Hansa yellow G, permanent yellow NCG, permanent orange GTR, pyrazolone orange G, benzidine orange G, permanent red 4R, watching red calcium salt, brilliant carmine 38, fast violet B, methyl. Examples include violet lake, phthalocyanine blue, fast sky blue, indanthrene blue BC and the like.

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 (I) shown below, in which the phthalocyanine skeleton is substituted with 2 to 3 substituents.

[0101]

[Chemical 5]

[Wherein X ₁ , X ₂ , X ₃ and X ₄ are

[0103]

[Chemical 6]

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. Basic Red 3b can be mentioned.

Regarding the content of yellow toner, which is sensitive to the transparency of the OHP film,
The amount is preferably 12 parts by mass or less, and more preferably 0.5 to 7 parts by mass with respect to 100 parts by mass of the binder resin.

When it exceeds 12 parts by mass, the reproducibility of green and red colors produced by mixing yellow with other colors is poor. In addition, the reproducibility of human skin color is also poor.

Other magenta toner and cyan toner are preferably not more than 15 parts by mass, more preferably 0.1 to 9 parts by mass with respect to 100 parts by mass of the binder resin.

As the black colorant, a mixture of dyes and pigments, carbon black, a metal oxide exhibiting a black color, or the like is preferably used. These colorants are used in an amount of 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, based on 100 parts by mass of the binder resin.

When a coloring agent having magnetism is used, it can also serve as a magnetic material and can be used as a magnetic toner. Magnetic powder as such a colorant, magnetite, hematite, iron oxide of ferrite, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium,
Alloys of metals such as calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof are used, and Si, Al,
Those containing compounds such as oxides of metal ions such as Mg, hydroxides, and hydroxides are preferably used. In particular, magnetic iron oxide containing silicon element is preferable, and its content is preferably 0.1 to 3 mass% based on the magnetic powder. It is more preferably 0.15 to 3% by mass, and particularly preferably 0.2 to 2.0% by mass.

The shape of the magnetic powder is hexahedron, octahedron,
A polyhedron such as a decahedron, a dodecahedron, a tetrahedron, a needle, a scale, a sphere, or an irregular shape is used.

[0112] The BET specific surface area by nitrogen gas adsorption method of magnetic ^{powder, 1m 2 / g~40m 2 / g} , more 2
It is preferably a m ² / g~30m ² / g, further,
It is preferably 3 m ² / g to ²⁰ m ² / g.

The saturation magnetization of the magnetic powder is 796 kA /
5 to 200 Am ² / kg, and further 10 to 10 in a magnetic field of m
The range of 150 Am ² / kg is preferable.

The residual magnetization of the magnetic powder is 796 kA /
1 to 100 Am ² / kg, further 1 to 7 in a magnetic field of m
0 Am ² / kg is preferred.

The average particle diameter of the magnetic powder is 0.03 to
1.0 μm, more preferably 0.05 to 0.6 μm,
Particularly preferably, the thickness is 0.1 to 0.4 μm.

The amount of the magnetic powder contained in the toner is 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.
Preferably 20 to 170 parts by mass, particularly preferably 30 to
It is 150 parts by mass.

The toner of the present invention using the above colorants is used as a one-component developer or a two-component developer.

In order to provide the toner of the present invention with an appropriate amount of charge, it is also preferable to add the following charge control agent. The degree of the charge control agent may vary depending on the other constituent materials, the kind of compound to be added, and the addition amount. You can control.

There are the following substances for controlling the toner to have a positive charge property.

Modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate;
And onium salts such as phosphonium salts which are analogs thereof and lake pigments thereof, (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid,
Ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate. A guanidine compound and an imidazole compound. These can be used alone or in combination of two or more. Among these, a triphenylmethane compound and a quaternary ammonium salt whose counter ion is not halogen are preferably used. In addition, the general formula (C)

[0121]

[Chemical 7] A monomer homopolymer represented by: styrene described above,
A copolymer with a polymerizable monomer such as acrylic acid ester and methacrylic acid ester can be used as a positive charge control agent. In this case, these charge control agents also function as (all or part of) the binder resin.

The following substances control the toner to be negatively charged.

Organic metal complexes and chelate compounds are effective, for example, monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid type metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, an azo metal complex represented by the following general formula (D) is preferable.

[0125]

[Chemical 8]

Particularly, Fe and Cr are preferable as the central metal, halogen, alkyl group and anilide group are preferable as the substituent, and hydrogen, ammonium and aliphatic ammonium are preferable as the counter ion.

Alternatively, the basic organic acid metal complex represented by the following general formula (E) also imparts a negative charging property and can be used in the present invention.

[0128]

[Chemical 9]

Particularly, as the central metal, Fe, Cr, Si,
Zn and Al are preferable, as the substituent, an alkyl group, an aryl group and halogen are preferable, and as the counter ion, hydrogen, ammonium and fatty acid ammonium are preferable.

As a method of incorporating the charge control agent into the toner, there are a method of adding it inside the toner and a method of adding it externally. The amount of these charge control agents used is determined according to the type of binder resin, the presence or absence of other additives, and the toner manufacturing method including the dispersion method, and is not uniquely limited. It is preferably used in an amount of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the binder resin. In addition, when adding externally, resin 1
It is preferably 0.01 to 10 parts by mass relative to 00 parts by mass, and particularly preferably mechanochemically fixed to the surface of the toner particles.

In the production of the toner according to the present invention, the toner constituent materials as described above are thoroughly mixed by a ball mill or other mixer, and then well kneaded by using a heat kneader such as a heat roll kneader or an extruder. It is preferable to obtain a toner by mechanically pulverizing and classifying the pulverized product after cooling and solidifying the kneaded product. Another method is to obtain a toner by dispersing constituent materials in a solution of a binder resin and then spray-drying; a predetermined material is mixed with a monomer that constitutes the binder resin, and an emulsion suspension is obtained. Then, there is a method for producing a toner by a polymerization method in which the toner is polymerized to obtain a toner. The toner according to the present invention may be a microcapsule toner including a core material and a shell material.

The toner of the present invention can be obtained by sufficiently mixing the above-mentioned toner with titanium oxide and alumina, which are the features of the present invention, with a mixer such as a Henschel mixer.

If necessary, the following additives may be added.

The following inorganic powders can be added to improve developability and durability. Magnesium, zinc,
Metal oxides such as aluminum, cerium, cobalt, iron, zirconium, chromium, manganese, strontium, tin and antimony; complex metal oxides such as calcium titanate, magnesium titanate and strontium titanate; calcium carbonate, magnesium carbonate, carbonic acid Examples thereof include metal salts such as aluminum; clay minerals such as caryon; phosphoric acid compounds such as apatite; silicon compounds such as silica, silicon carbide and silicon nitride; carbon powders such as carbon black and graphite. Of these, zinc oxide, aluminum oxide, cobalt oxide, manganese dioxide, strontium titanate, magnesium titanate and the like are preferable.

For the same purpose, the following organic particles and composite particles can be added. Resin particles such as polyamide resin particles, silicone resin particles, silicone rubber particles, urethane particles, melamine-formaldehyde particles, and acrylic resin particles; rubbers, waxes, fatty acid compounds, resins, etc. and metals, metal oxides, salts, carbon black, etc. Examples of the composite particles include the above-mentioned inorganic particles.

Further, the following lubricant powder can be added. Fluorine resins such as Teflon and polyvinylidene fluoride; fluorine compounds such as carbon fluoride; fatty acid metal salts such as zinc stearate; fatty acid derivatives such as fatty acids and fatty acid esters; molybdenum sulfide, amino acids and amino acid derivatives.

When the toner of the present invention is used as a two-component type developer, it is used by mixing it with a carrier, and the mixing ratio of the toner and the carrier is 0.1 to 50% by mass as the toner concentration, and it is preferable. Is 0.5 to 20% by mass, and more preferably 3 to 10% by mass.

As the carrier core material, for example, surface-oxidized or unoxidized iron, cobalt, nickel, copper, zinc, manganese, chromium rare earth metals, their alloys, compounds, oxides, magnetic ferrites and the like are used. Above all, those containing 98% by mass or more of the ferrite carrier are preferably used. There are no particular restrictions on the method of manufacturing the carrier. A coated carrier in which the surface of the core material is coated with a resin or the like is particularly preferable. As a coating method, a coating material such as a resin is dissolved or suspended in a solvent to prepare a coating solution, and the coating solution is applied to the surface of carrier particles and adhered to the surface of carrier particles, or simply carrier particles and coating. A conventionally known method such as a method of dry mixing powders can be applied.

The binder resin used for coating the coated carrier includes styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl acetate and vinyl propionate.
Vinyl esters such as vinyl benzoate and vinyl butyrate; methyl acrylate, ethyl acrylate, butyl acrylate,
Dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate,
Α-Methylene aliphatic monocarboxylic acid esters such as butyl methacrylate and dodecyl methacrylate Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone alone Examples thereof include polymers and copolymers. Particularly, typical binder resins include polystyrene and styrene from the viewpoints of dispersibility of conductive fine particles, film forming property as a coat layer, toner spent prevention, and productivity. -Alkyl acrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene. Furthermore, polycarbonate, phenol resin,
Examples thereof include polyester, polyurethane, epoxy resin, polyolefin, fluororesin, silicone resin and polyamide. In particular, from the viewpoint of preventing spent, it is more preferable to contain a resin having a small critical surface tension, such as polyolefin, fluororesin, and silicone resin.

As for the blending amount, the proportion of the fluorine-based resin, the polyolefin-based resin or the silicone-based resin with respect to the total amount of the binder is appropriately 1.0 to 60% by mass, and particularly preferably 2.0 to 40% by mass. Content is 1.
If it is less than 0% by mass, the effect of surface modification is insufficient and the toner spent is not effective. On the other hand, if it exceeds 60% by mass, it is difficult to uniformly disperse the both, so that partial unevenness occurs in the volume resistance value, and the charging characteristics deteriorate.

Examples of the fluororesin used as the binder resin in the present invention include vinyl fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, dichlorodifluoroethylene, tetrafluoroethylene, hexafluoropropylene and the like. And a solvent-soluble copolymer with the monomer of.

The silicone resin used as the binder resin in the present invention is, for example, KR27 manufactured by Shin-Etsu Silicone Co., Ltd.
1, KR282, KR311, KR255, KR155
(Straight silicone varnish), KR211, KR2
12, KR216, KR213, KR217, KR92
18 (Modifying Silicone Varnish), SA-4, KR20
6, KR5206 (Silicone alkyd varnish), E
S1001, ES1001N, ES1002T, ES1
004 (Silicone Epoxy Varnish), KR9706
(Silicone acrylic varnish), KR5203, KR5
221 (silicone polyester varnish) and SR2100, SR2101, SR210 manufactured by Toray Silicone Co., Ltd.
7, SR2110, SR2108, SR2109, SR
2400, SR2410, SR2411, SH805,
SH806A, SH840 and the like are used.

The amount of the above-mentioned materials used may be appropriately determined, but generally, the total amount is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, based on the carrier.

The average particle size of the carrier is 20 to 100 μm,
Preferably 25-70 μm, more preferably 25-65
It is preferable to have μm.

As a particularly preferred carrier, Cu-Z
n-Fe [composition weight ratio (5 to 20): (5 to 20):
(30-80)] ternary ferrite particles, the surface of which is coated with a fluorine resin, a styrene resin, a silicone resin, or a mixed resin thereof. For example, polyvinylidene fluoride and styrene-methyl methacrylate resin as mixed resins; polytetrafluoroethylene and styrene-methyl methacrylate resin;
Fluorine-based copolymer and styrene-based copolymer; 90: 1
Mixtures in a weight ratio of 0 to 20:80, preferably 70:30 to 30:70 are mentioned. Apply the coating agent to 0.
As a preferred carrier, a coated magnetic ferrite carrier having a mean particle size of 01 to 5% by mass, preferably 0.1 to 1% by mass, and having 70% by mass or more of carrier particles passing through 250 mesh and turned on to 350 mesh is 70% by mass or more. Can be mentioned. As the fluorine-based copolymer, vinylidene fluoride-tetrafluoroethylene copolymer (1
0:90 to 90:10), and the styrene-based copolymer is a styrene-2-ethylhexyl acrylate copolymer (20:80 to 80:20), styrene-2-ethylhexyne acrylate-methyl methacrylate. The copolymer (20-60: 5-30: 30-10) is illustrated.

The above coated magnetic ferrite carrier having a sharp particle size distribution has an effect of imparting preferable triboelectrification to the toner of the present invention and further improving electrophotographic characteristics.

When the toner of the present invention is used as a color toner and mixed with a carrier to prepare a two-component developer, the mixing ratio is 1% by mass to the toner concentration in the developer.
Good results are usually obtained with 15% by weight, preferably 2% to 13% by weight. If the toner concentration is less than 1% by mass, the image density will be low, and if it exceeds 15% by mass, fog and in-machine scattering will increase, and the useful life of the developer tends to be shortened.

Since the toner of the present invention has good releasability and excellent transferability, it is used in the image forming method for transferring the toner image formed on the latent image holding member to the recording material or the intermediate transfer material. It is preferably used for an image forming method in which toner images on a plurality of latent image holding members are transferred in multiple layers onto the intermediate transfer member or the intermediate transfer member.

Further, in the image forming method of transferring the toner image formed on the latent image holding member or the intermediate transfer member to the recording material, a plurality of toners are formed on the latent image holding member or the intermediate transfer member. It is also preferably used in an image forming method for collectively transferring multiple toner images onto a recording material.

[0150]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited thereto. A description will be given of the constituent materials of the toner used in the present invention,
First, titanium oxide will be described.

[Heat Treatment Titanium Oxide Production Example] Table 1 shows the particles to be treated used in the examples.

[0152]

[Table 1]

The heat treatment can be carried out by the following heating method examples.

[Heat Treatment Method Example 1 (Heating Method 1)] In a furnace having a structure as shown in FIG. 2, heating was performed at 700 ° C. for 10 hours under reduced pressure. Then, the mixture was cooled at room temperature, returned to room temperature, heated again under the same conditions for 5 hours, and then cooled at room temperature. Then, it was crushed by a ball mill.

[Heat Treatment Method Example 2 (Heat Treatment Method 2)] In a furnace having a structure as shown in FIG.
Heating was performed at 100 ° C. for 10 hours. After that, it was cooled at room temperature.

[Heat Treatment Method 3 (Heating Method 3)] In a furnace having a structure as shown in FIG.
Heating was carried out at 0 ° C. for 10 hours. After that, it was cooled at room temperature.

[Heat Treatment Method Example 4 (Heating Method 4)] In a furnace having a structure as shown in FIG. 2, heating was performed under reduced pressure at 450 ° C. for 24 hours. Then, the mixture was cooled at room temperature, returned to room temperature, heated again under the same conditions for 5 hours, and then cooled at room temperature. Then, it was crushed by a ball mill.

Table 2 shows the production method and physical properties of the treated particles used in the examples.

[0159]

[Table 2]

[Production Example of Binder Resin]   (Polyester resin 1)   Terephthalic acid 6.0 mol   n-dodecenyl succinic anhydride 3.0 mol   Bisphenol A Propylene oxide 2.2 mol Addition product 10.0 mol   Dibutyltin oxide 0.05g

The above compound was put in a reactor, equipped with a thermometer, a stir bar, a condenser, and a nitrogen introducing tube, and after substituting with nitrogen, the temperature was gradually raised with stirring, and the reaction was carried out at 170 ° C. for 5 hours, then at 190 ° C. The temperature was raised to 4, and the reaction was performed for 4 hours.
Then, the following compounds were added.

[0162]   Trimellitic anhydride 0.7mol   Dibutyltin oxide 0.3g

Then, the reaction was carried out at 190 ° C. for 3 hours, the temperature was further raised to 200 ° C., the pressure was reduced (15 hPa) and the reaction was carried out for 5 hours for dehydration condensation, and the reaction was completed to obtain polyester resin 1.

This polyester resin had a peak molecular weight of 8,700 and a glass transition point of 64 ° C.

[0165]   (Polyester resin 2)   Fumaric acid 9.5 mol   Bisphenol A Propylene oxide 2.2 mol Addition product 10.0 mol   Dibutyltin oxide 0.5g

The above compound was put in a reactor, equipped with a thermometer, a stir bar, a condenser and a nitrogen introducing tube, and after substituting with nitrogen, the temperature was gradually raised with stirring, the reaction was carried out at 220 ° C. for 6 hours, and then the pressure was reduced ( (15 hPa) and reacted for 2 hours for dehydration condensation, and the reaction was terminated to obtain polyester resin 2.

This polyester resin had a peak molecular weight of 9,800 and a glass transition point of 58 ° C.

[0168]   (Polyester resin 3)   Terephthalic acid 9.5 mol   Bisphenol A Propylene oxide 2.2 mol Addition product 5.0 mol   Cyclohexanedimethanol 5.0 mol   Dibutyltin oxide 1.0g

The above compound was put in a reactor, equipped with a thermometer, a stir bar, a condenser and a nitrogen introducing tube, and after substituting with nitrogen, the temperature was gradually raised with stirring, the reaction was carried out at 240 ° C. for 6 hours, and then the pressure was reduced ( 15 hPa) and reacted for 2 hours for dehydration condensation, and the reaction was completed to obtain polyester resin 3.

This polyester resin had a peak molecular weight of 9,100 and a glass transition point of 62 ° C.

[0171]   (Epoxy resin 4)   Bisphenol A type liquid epoxy resin 2000g   (A condensate of bisphenol A and epichlorohydrin     Epoxy equivalent 188, viscosity 13000 mPa · s / 25 ° C)   Bisphenol A 937g   p-cumylphenol 559g   Xylene 400g

The above compound was put in a reactor, equipped with a thermometer, a stir bar, a condenser and a nitrogen introducing tube, and after substituting with nitrogen, the temperature was gradually raised to 70 ° C. with stirring, and lithium chloride content was 0.64 g of 5N. An aqueous solution was added, the temperature was raised to 170 ° C., xylene and water were distilled off under reduced pressure, the reduced pressure was released, and the reaction was carried out for 6 hours. Here, ε-caprolactone 18
4 g was added and reacted for 6 hours to obtain a modified epoxy polyol resin (epoxy resin 4).

This polyester resin had a peak molecular weight of 7,600 and a glass transition point of 60 ° C.

[0174]   (Styrene resin 5)   Styrene 1600g   Butyl acrylate 400g   2,2-bis (4,4-di-t-butylperoxycyclo 4g   Hexyl) propane

Polymer A was obtained from the above compound by the suspension polymerization method.

[0176]   Styrene 2550g   Butyl acrylate 450g   Di-t-butyl peroxide 60g

Polymer B was obtained from the above compound by a solution polymerization method using xylene as a solvent.
The solutions were mixed in a weight ratio of 5:75 to obtain styrene resin 5.

This styrene resin has a peak molecular weight of 9,
The glass transition points were 400, 720,000 and 60 ° C.

[Production Example of Classified Product]   (Classified product 1)   Polyester resin 1 10 parts by mass   Copper phthalocyanine phthalimide derivative pigment 5 parts by mass   Di-t-butylsalicylic acid chromium complex 4 parts by mass

The above raw materials were premixed by a Henschel mixer, and then melt-kneaded by a twin-screw extruder set at 130 ° C. After cooling the kneaded product, it is finely pulverized by a pulverizer using a jet stream and classified by an air classifier,
A cyan classified product 1 having a weight average diameter of 8 μm was obtained.

[0181]   (Classified product 2)   Polyester resin 2 10 parts by mass   Copper phthalocyanine phthalimide derivative pigment 5 parts by mass   Di-t-butylsalicylic acid chromium complex 4 parts by mass

The above raw materials were premixed by a Henschel mixer, and then melt-kneaded by a twin-screw extruder set at 130 ° C. After cooling the kneaded product, it is finely pulverized by a pulverizer using a jet stream and classified by an air classifier,
Cyan classified product 2 having a weight average diameter of 8 μm was obtained.

Further, the pigment may be C.I. I. Pigment Re
d 122 5 parts by mass, C.I. I. Pigment Ye
low 17 3.5 parts by mass, carbon black 5
Magenta classified product 2, except for changing to mass parts
Yellow classified product 2 and black classified product 2 were obtained.

[0184]   (Classified product 3)   Polyester resin 3 10 parts by mass   Copper phthalocyanine phthalimide derivative pigment 5 parts by mass   Di-t-butylsalicylic acid chromium complex 4 parts by mass

The above raw materials were premixed by a Henschel mixer, and then melt-kneaded by a twin-screw extruder set at 130 ° C. After cooling the kneaded product, it is finely pulverized by a pulverizer using a jet stream and classified by an air classifier,
A cyan classified product 3 having a weight average diameter of 8 μm was obtained.

Further, the pigment is C.I. I. Pigment Re
d 122 5 parts by mass, C.I. I. Pigment Ye
low 17 3.5 parts by mass, carbon black 5
Magenta classified product 3 in the same manner except that it is changed to the mass part,
Yellow classified product 3 and black classified product 3 were obtained.

[0187]   (Classified product 4)   Polyester resin 4 10 parts by mass   Copper phthalocyanine phthalimide derivative pigment 5 parts by mass   Di-t-butylsalicylic acid chromium complex 4 parts by mass

The above raw materials were premixed by a Henschel mixer, and then melt-kneaded by a twin-screw extruder set at 130 ° C. After cooling the kneaded product, it is finely pulverized by a pulverizer using a jet stream and classified by an air classifier,
A cyan classified product 4 having a weight average diameter of 8 μm was obtained.

The pigment may be C.I. I. Pigment Re
d 122 5 parts by mass, C.I. I. Pigment Ye
low 17 3.5 parts by mass, carbon black 5
Magenta classified product 4 in the same manner except that the mass part is changed,
Yellow classified product 4 and black classified product 4 were obtained.

[0190]   (Classified product 5)   Styrene resin 5 100 parts by mass   Copper phthalocyanine phthalimide derivative pigment 5 parts by mass   Di-t-butylsalicylic acid chromium complex 4 parts by mass   Low molecular weight ethylene propylene copolymer 3 parts by mass

The above raw materials were premixed by a Henschel mixer, and then melt-kneaded by a twin-screw extruder set at 130 ° C. After cooling the kneaded product, it is finely pulverized by a pulverizer using a jet stream and classified by an air classifier,
A cyan classified product 5 having a weight average diameter of 8 μm was obtained.

Further, the pigment is C.I. I. Pigment Re
d 122 5 parts by mass, C.I. I. Pigment Ye
low 17 3.5 parts by mass, carbon black 5
Magenta classified product 5, except for changing to mass parts
Yellow classified product 5 and black classified product 5 were obtained.

[0193]   (Classified product 6)   Styrene resin 5 100 parts by mass   80 parts by weight of magnetite (magnetic iron oxide)   Di-t-butylsalicylic acid chromium complex 4 parts by mass   Low molecular weight ethylene propylene copolymer 3 parts by mass

The above raw materials were premixed by a Henschel mixer, and then melt-kneaded by a twin-screw extruder set at 130 ° C. After cooling the kneaded product, it is finely pulverized by a pulverizer using a jet stream and classified by an air classifier,
A black classified product 6 having a weight average diameter of 8 μm was obtained.

[Production Example of Toner and Developer] Classified Product 1
To 100 parts by mass, the formulation shown in Table 3 was sufficiently stirred with a Henschel mixer, and the titanium oxide and alumina of the present invention were externally added and mixed to obtain a toner.

Cyan toners 1 to 7, magenta toner 1,
The yellow toner 1 and the black toner 1 are styrene-methyl methacrylate copolymer (weight ratio 65:35) of 0.3.
A Cu-Zn-Fe ferrite carrier coated with 35 wt% was mixed with a toner concentration of 5 wt% to obtain a developer.

The cyan toner 8, the magenta toner 2, the yellow toner 2 and the black toner 2 are mixed with a Cu-Zn-Fe ferrite carrier coated with a silicone resin in an amount of 0.45 wt% so as to have a toner concentration of 5 wt%, and then developed. I used it as an agent.

The cyan toner 11, the magenta toner 5, the yellow toner 5, and the black toner 5 are 0.3 parts by weight of a styrene-butyl methacrylate copolymer (weight ratio 80:20).
5 wt% and a Cu—Zn—Fe ferrite carrier coated with 0.15 wt% of a silicone resin were mixed with each other so that the toner concentration was 7 wt% to obtain a developer.

For the cyan toner 10, the magenta toner 4, the yellow toner 4 and the black toner 4, 2.5% styrene-methyl methacrylate copolymer (weight ratio 65:35) was used.
A developer was prepared by mixing a Cu-Fe ferrite carrier coated with wt% and a toner concentration of 7 wt%.

The cyan toner 9, the magenta toner 3, the yellow toner 3 and the black toner 3 are 0.35 of a styrene-methyl methacrylate copolymer (weight ratio 15:85).
wt% and a Cu—Zn—Fe ferrite carrier coated with a fluororesin of 0.15 wt% were mixed to give a toner concentration of 7 wt% to obtain a developer.

The black toner 6 was used as it was without using a carrier.

[Example 1] A developer prepared from cyan toner 1 was treated with a commercially available digital full-color electrophotographic copying machine (color laser copier 550 manufactured by Canon Inc.) having the structure shown in Fig. 3 at 23 ° C and 60% RH. Below 10,
A printing durability test of 00 sheets was performed.

Regarding the density, a Macbeth densitometer RD918 type (manufactured by Macbeth Co.) was used to measure the reflection density using an SPI filter, and a 5 mm circle image was measured to obtain the image density.

The fogging on the image was carried out by using a reflection densitometer (Reflectometer model TC-6DS manufactured by Tokyo Denshoku Co., Ltd.), and the worst value of the white background reflection density after image formation was Ds,
Let Dr be the reflection average density of the transfer material before image formation, and Ds-
The fogging was evaluated using Dr as the fogging amount. If this value is 1% or less, fogging is at a very good level, if it is 1.5% or less, the image is substantially good in fogging, and if it is 2% or less, there is no practical problem.

The transfer efficiency is obtained from the change in the Macbeth density of the toner image before and after the transfer on the photosensitive member when the transfer current is 250 μA. When the Macbeth density of the image after fixing on the transfer paper becomes 1.5, the images before and after transfer on the photosensitive drum are transferred with polyester film adhesive tape, and each tape is attached to the transfer paper, and the Macbeth density is measured. Do. When the density before transfer is Da, the density after transfer is Db, and the density of only the tape is Dc, the transfer efficiency is defined by the following formula. Transfer efficiency = {[(Da-Dc)-(Db-Dc)] /
(Da-Dc)} × 100

That is, the higher this value, the higher the transfer efficiency and the better the transferability.

With regard to the transfer latitude, a 16-gradation image is formed, and the transfer image obtained by changing the transfer current is fixed and visually determined. The range of the transfer current is obtained in which an image with all gradations is obtained with transfer unevenness, roughness, and good skipping. That is, if the transferability is excellent, the image can be transferred properly even at a low transfer current, and an image having a stable image density and a gradation can be obtained without transfer unevenness. Further, since the toner having excellent transferability does not cause the transfer current to be higher than necessary, it is possible to obtain a good image without roughness and flicker. In other words, a good transfer begins with a low transfer current value and has a wide range up to the transfer upper limit.
A toner with excellent transferability and a wide transfer latitude. That is, if the transfer latitude is wide, the applicable range of the transfer material and the image forming environment is widened, and the transfer control of the image forming apparatus can be facilitated.

The transfer dropout was visually evaluated for the printout. A: There are almost no voids. B: There is a slight hollow. C: There is a hollow, but there is no problem in practical use. D: Hollow-out is conspicuous and practically impossible.

The gradation was judged by visually observing an image with 16 gradations. A: 16 gradations can be confirmed, there is no roughness in the halftone part, and the highlight part is reproduced properly. B:
16 gradations can be confirmed, but some roughness is seen in the halftone part. C: The reproduction of the highlight part is getting worse, but there is no practical problem. D: 14 gradations or more could not be confirmed and practically impossible.

Table 4 shows the initial stage of the test, the 1,000th sheet, and 1
The fog of 50,000th sheet, the image density, the omission of transfer in the line portion, and the gradation are shown. Table 5 shows the transfer efficiency and the transfer latitude at 1,000 sheets.

Further, a printing durability test was conducted in an environment of 30 ° C. and 80% RH. The developing device and the toner for replenishment were allowed to adapt to the test environment for one week, and then started, and 1,000 sheets were printed. After that, it was left in this environment for 1 week and restarted, and 1,000 sheets were printed, and then left for 2 weeks and 1,000 sheets were printed. Initial of each step, 100
Tables 6, 7, and 8 show the fogging of the 1st and 1,000th sheets, the image density, the void in the transfer of the line portion, and the gradation.

As shown in Tables 4 and 5 and Tables 6, 7, and 8, the cyan toner 1 according to the present invention has a high image density, no fog, and no void in the line portion under normal environment and high temperature and high humidity. And a clear cyan image with excellent gradation was obtained. Further, the transfer efficiency was good, and the toner had a wide transfer latitude.

[Examples 2 to 7] Cyan toners 4 to 9 were evaluated in the same manner as in Example 1 and the results are shown in Tables 4 and 5 and Tables 6 and 6, respectively.
7 and 8.

[Comparative Example 1] The cyan toner 2 was evaluated by the same evaluation method as in Example 1 and the results are shown in Tables 4 and 5 and Tables 6 and 7 and 8 where hollow characters were observed. , The transfer latitude was narrow. In addition, the developability under high humidity was poor, and the fog at the initial stage and after starting after standing was bad.

[Comparative Example 2] The results of evaluation of cyan toner 3 by the same evaluation method as in Example 1 are shown in Tables 4, 5 and 6, 7, 8. There was no problem in practical use in the character part omission and the transfer latitude. However, it was inferior in the developability under high humidity, and the fog at the initial stage and at the start after standing was bad.

[Embodiment 8] A developer prepared from cyan toner 1, magenta toner 1, yellow toner 1 and black toner 1 is a commercially available digital full color electrophotographic copying machine (color laser copier 550 manufactured by Canon Inc.).
At 23 ° C. and 60% RH, a full-color copying test of 2,000 sheets was performed. As a result, a beautiful pictorial image having excellent color reproduction and gradation and no color unevenness was obtained, and almost no color difference was observed in the image being copied.

Further, a copy test was conducted in an environment of 30 ° C. and 80% RH. The developing device and the replenishing toner were soaked in the test environment for one week, and then 500 copies were made. Then, after leaving it in this environment for one week, it was restarted and a 500-copy test was conducted. As a result, a beautiful full-color image was obtained, and the fog was 1.5% or less in the worst value when four colors were overlaid, and there was no problem at the initial stage and restart.

[Embodiment 9] A developer prepared from cyan toner 10, magenta toner 2, yellow toner 2 and black toner 2 was used at 23 ° C. and 60% RH in a digital full color image forming apparatus shown in FIG. A full-color copy test of 1,000 sheets was performed.

The image forming apparatus shown in FIG.
Image forming parts Pa, Pb, Pc and Pd are arranged in
The drive rollers 31, 3 are located below the image forming unit.
A transfer material conveying means around which a belt 28 is wound is disposed between the two rollers 2, 46, and the belt 28 is rotated in the arrow direction. The transfer material 47 is fed to the right side of the belt 28 via the paper feed mechanism 33. The transfer material 47 that has been transferred at the image forming portions Pa, Pb, Pc, and Pd is sent to the fixing device 27 from the left side of the belt 28. Then, the apparatus main body 30 passes through the discharge port 34 of the fixed transfer material 47.
It is discharged to the outside. The first and the first installed in parallel above the transporting means
The second, third, and fourth image forming portions Pa, Pb, Pc, and Pd are photosensitive members 21a, 21b, 21 as latent image holding members.
c and 21d are separately held, and the photoconductors 21a,
Chargers 22a, 22b, 22c, and 22d are provided on the upper left side of each of 21b, 21c, and 21d.

Laser beam scanners 36a, 36 are provided above the photoconductors 21a, 21b, 21c, 21d.
b, 36c and 36b are provided, each of which is composed of a semiconductor laser, a polygon mirror, an fθ lens, etc., receives an electric digital image signal read from a document, and is modulated in accordance with the signal. The laser beam to the chargers 22a, 22b, 22c and 22d,
A latent image is formed by scanning the developing devices 23a, 23b, 23c and 23d in the generatrix direction of the photoconductors 21a, 21b, 21c and 21d and exposing them. To further elaborate on this point, the pixel signal corresponding to the yellow component of the color image is supplied to the laser scanner 36a of the first image forming unit Pa and the magenta component of the color image is supplied to the laser scanner 36b of the second image forming unit Pb. Corresponding pixel signals are input, and the pixel signal corresponding to the cyan component image and the black component image are input to the laser scanner 36c of the third image forming unit Pc and the laser scanner 36d of the fourth image forming unit Pd. And the pixel signal corresponding to

The paper feed mechanism 33 includes a paper feed guide 37 and a sensor 38. When the transfer material 47 is inserted into the paper feed guide 37, the sensor 38 detects the tip of the transfer material 47 and the photoconductors 21a, 21b. , 21c and 21d are sent to start rotation, and at the same time drive rollers 31, 32, 46 are also driven,
The belt 28 is rotated. Further, the transfer material 47 fed to the belt 28 is subjected to corona discharge from the attraction chargers 39 and 42, and is reliably attracted to the surface of the belt 28. In this embodiment, the high-voltage polarities of the adsorption chargers 39 and 42 are set to be opposite to each other.
It has the same polarity as the transfer chargers 24a, 24b, 24c and 24d.

However, the tip of the transfer material 47 is placed on each sensor 4
0a, 40b, 40c, and 40d are sent to the position where they are cut off, and the photoconductors 21a, 2 that are rotating by the signal
Image formation for 1b21c and 21d is sequentially started. When the transfer material 47 passes through the fourth image forming portion Pd, A
The C voltage is applied to the static eliminator 35, the charge of the transfer material 47 is eliminated, and the transfer material 47 is separated from the belt 28. Then, the transfer material 47 enters the fixing device 27, the image is fixed, and the sheet is discharged from the discharge port 34.

In the above embodiment, the belt 28 used as the conveying means is made of a material having a small elongation and capable of efficiently transmitting the rotation control of the driving roller, for example, a polyurethane belt (made by Hokushin Kogyo Co., Ltd.). To be done. Further, structurally, it is desirable that the transfer corona current related to the transfer process is not significantly affected. The belt is preferably made of polyurethane having a thickness of about 100 μm, a rubber hardness of 97 degrees, and a tensile elastic modulus of 16000 Kg / cm ² .

As the transfer conditions, the total transfer current of each image forming unit is set to 450 μA, the distance between the transfer discharge wire and the drum is set to 11 mm, and the distance between the transfer discharge wire and the electrode back plate is set to 8.5 mm (both left and right). There is. Further, the attraction and charging conditions prior to the transfer are the same as those of the transfer chargers 24a to 24d for both of the attraction upper and lower chargers 39 and 42, and the total current value 200 is equal to the upper and lower sides.
μA, the distance between the discharge wire and the conveyor belt is set to 11 mm.

As a result, a beautiful pictorial image having excellent color reproduction and gradation and no color unevenness was obtained, and almost no color difference was observed in the image being copied.

Further, a copy test was conducted in an environment of 30 ° C. and 80% RH. The developing device and the replenishing toner were soaked in the test environment for one week, and then 500 copies were made. Then, after leaving it in this environment for one week, it was restarted and a 500-copy test was conducted. As a result, a beautiful full-color image was obtained, and the fogging was 1.4% or less in the worst value when four colors were overlaid, and there was no problem at the initial stage and restart.

Since the toner of the present invention is excellent in transferability, even if the charge amount of the conveying means increases each time transfer is repeated,
With the same transfer current, the transferability of the toner in each transfer can be made uniform, and the same density can be obtained, so that a high-quality and high-quality image can be obtained, and the attraction of the transfer material onto the conveyor belt is not deteriorated. Moreover, since the transfer performance can be made uniform while the transfer conditions of the respective image forming sections are set to be the same, control at the time of full-color image formation was also easy.

[Embodiment 10] A commercially available digital full-color electrophotographic copying machine using a transfer belt as an intermediate transfer member of a developer prepared from cyan toner 11, magenta toner 3, yellow toner 3 and black toner 3 (Pretail 55).
0 Ricoh Co., Ltd.), and a full-color copying test of 2,000 sheets was performed at 23 ° C. and 60% RH. As a result, a beautiful full-color image having excellent color reproduction and no color unevenness was obtained, and almost no color difference was observed in the image during copying.

Further, a copy test was conducted in an environment of 30 ° C. and 80% RH. The developing device and the replenishing toner were soaked in the test environment for one week, and then 500 copies were made. Then, after leaving it in this environment for one week, it was restarted and a 500-copy test was conducted. As a result, a beautiful full-color image was obtained and the fog was 1.6% or less in the worst value when four colors were overlaid, and there was no problem at the initial stage and restart.

[Embodiment 11] A commercially available digital full-color electrophotographic copying machine (U-Bix9028 Konica Corporation) of a multi-development batch-transfer type of a developer prepared from cyan toner 12, magenta toner 4, yellow toner 4 and black toner 4 is used. Manufactured) at 23 ° C. and 60% RH for 2,0
A full-color copy test of 00 sheets was performed. As a result, a beautiful full-color image having excellent color reproduction and no color unevenness was obtained, and almost no color difference was observed in the image during copying.

Further, a copy test was conducted in an environment of 30 ° C. and 80% RH. The developing device and the replenishing toner were soaked in the test environment for one week, and then 500 copies were made. Then, after leaving it in this environment for one week, it was restarted and a 500-copy test was conducted. As a result, a beautiful full-color image was obtained, and the fogging was 1.2% or less in the worst case when four colors were overlaid, and there was no problem at the initial stage and restart.

[Embodiment 12] A developer prepared from cyan toner 13, magenta toner 5, yellow toner 5 and black toner 5 was used in a commercially available digital full color electrophotographic copying machine (A color 635, manufactured by Fuji Xerox Co., Ltd.). A full-color copying test of 2,000 sheets was conducted at 23 ° C. and 60% RH. As a result, a beautiful full-color image having excellent gradation and no color unevenness was obtained, and almost no color difference was observed in the image during copying.

Further, a copy test was conducted in an environment of 30 ° C. and 80% RH. The developing device and the replenishing toner were soaked in the test environment for one week, and then 500 copies were made. Then, after leaving it in this environment for one week, it was restarted and a 500-copy test was conducted. As a result, a good full-color image was obtained, and the fog was 1.8% or less in the worst value when four colors were overlaid, and there was no problem at the initial stage and restart.

Example 13 A developer prepared from cyan toner 1, magenta toner 1, yellow toner 1 and black toner 6 was applied to a commercially available digital full color electrophotographic copying machine (Color Laser Copier 550 manufactured by Canon Inc.). A printing durability test of 2,000 sheets was performed at 23 ° C. and 60% RH. At this time, the doctor blade of the black developing device was remodeled to develop and transfer from black. As a result, a beautiful pictorial image having excellent color reproducibility and gradation and no color unevenness was obtained, and almost no color difference was observed in the image during copying.

Further, a copy test was conducted in an environment of 30 ° C. and 80% RH. The developing device and the replenishing toner were soaked in the test environment for one week, and then 500 copies were made. Then, after leaving it in this environment for one week, it was restarted and a 500-copy test was conducted. As a result, a beautiful full-color image was obtained, and the fogging was 1.3% or less in the worst value when four colors were overlaid, and there was no problem at the initial stage and restart.

[0236]

[Table 3]

[0237]

[Table 4]

[0238]

[Table 5]

[0239]

[Table 6]

[0240]

[Table 7]

[0241]

[Table 8]

[0242]

EFFECT OF THE INVENTION The toner for developing an electrostatic charge image of the present invention achieves hydrophobicity without organic surface treatment and contains titanium oxide having a high degree of methanol hydrophobization, so that it has moisture resistance, chargeability and fluidity. The toner is excellent in developability, transferability and leaving stability, and can be a toner excellent in transferability and durability especially under high temperature and high humidity.

That is, the toner has sufficient developability even under high humidity or left for a long time.

Further, it is a toner which has a high transfer efficiency and a wide transfer latitude and a beautiful pictorial full-color image can be easily obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing reactive hydroxyl groups having different properties existing on the surface of titanium oxide.

FIG. 2 is an explanatory diagram of an apparatus used for heat treatment of heat-treated titanium oxide according to an example of the present invention.

FIG. 3 is a schematic view showing an image forming apparatus used in an example of the present invention.

FIG. 4 is a schematic view showing an image forming apparatus used in an example of the present invention.

[Explanation of symbols]

1 Photosensitive drum (latent image holder) 2 Development unit 2-1, 2,3,4 developing device 3 exposure means 4 charger 5 holding member 6 transfer drum 7 gripper 8 Transfer charger 9 Separation charger 10 Paper feed roller 11 separate nails S transfer material Pa, Pb, Pc, Pd Image forming unit 21a, 21b, 21c, 21d Photoreceptor 22a, 22b, 22c, 22d Charging device 23a, 23b, 23c, 23d Developing device 24a, 24b, 24c, 24d Transfer charger 25a, 25b, 25c, 25d Cleaning unit 27 Fixer 28 Conveyor belt 30 body 31 drive roller 32 drive roller 33 paper feed mechanism 34 outlet 35 Static eliminator 36a, 36b, 36c, 36d Laser scanner 37 Paper feed guide 38 sensors 39 Charging device for adsorption 40a, 40b, 40c, 40d sensors 42 Charging device for adsorption 46 drive roller 47 Transfer material

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 59-231552 (JP, A) JP 58-186750 (JP, A) JP 4-340972 (JP, A) JP 4- 340971 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (2)

(57) [Claims] 1. The surface of titanium oxide is treated with an organic hydrophobizing agent.
Not been an organic process I, methanol degree of hydrophobicity 35
% Or more of the titanium oxide particles are externally added to the toner for developing an electrostatic image. 2. The titanium oxide particles are nitrogen and helium.
Aeration with any inert gas selected from the group consisting of
Luke, or under reduced pressure, toner according to claim 1, characterized in this <br/> and those that are hydrophobic by heat treatment at a temperature 600 ° C. to 1800 ° C. .