JP3034371B2 - Toner for electrostatic image development - 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 image formed in electrophotography, electrostatic printing, electrostatic recording and the like.

[0002]

2. Description of the Related Art In general, a toner for developing an electrostatic image is composed of a resin component, a colorant component composed of a pigment or a dye, and additional components such as a release agent and a charge control agent.
As the resin component, a natural or synthetic resin is used alone or in an appropriate mixture. Many improvements have been made to the resin components of toners suitable for the dry development system, which have been rapidly developed in recent years. In particular, in an electrophotographic copying machine intended for high-speed copying, a heating roll is used.
The toner image obtained by development on an electrostatic recording medium (photosensitive drum) is temporarily transferred to a transfer sheet such as paper by adopting a color fixing method.
After transfer to the sheet, the transfer sheet is passed through a fixing roller that performs heat and pressure bonding to fuse the toner image to the sheet, thereby fixing the sheet.

[0003] Various fixing methods are known. In particular, a contact heat fixing method represented by a heat roller fixing machine is compared with a non-contact heat fixing method such as a hot plate fixing device. This is excellent in that the thermal efficiency is high, and is particularly preferable in that high-speed fixing is possible.

In this contact heating fixing system, toner
From the viewpoint of the physical properties of the binder resin, copy speed, power consumption, maintenance of the image forming apparatus and other workability.
Fixing is performed within a temperature range of 150 to 220 ° C.

Therefore, in the toner used in this fixing method, a low molecular weight polymer is added to the binder resin so that the fixing is reliably achieved at the fixing temperature.
It is considered preferable that the binder resin contains a high molecular weight polymer to increase the toner elastic modulus so as to reduce the viscosity and prevent the offset phenomenon caused by the partial adhesion of the toner to the contact heating roller. ing.

[0006] In electrophotographic copying machines intended for high-speed copying, a so-called two-component dry developer comprising a mixture of carrier particles and toner particles is often used. In this two-component dry developer, fine toner particles are held on the surface of relatively large carrier particles by an electric force generated by friction between the two particles. The attracting force of the toner particles in the direction of the latent image due to the electric field generated by the image overcomes the bonding force between the toner particles and the carrier particles, and the toner particles are attracted and adhered on the electrostatic latent image, and the electrostatic latent image is formed. The image is to be visualized. The developer is used repeatedly while replenishing the toner consumed by the development.

Therefore, the carrier must be triboelectrically charged to a desired polarity and to a sufficient charge amount at all times during use for a long period of time. However, in a conventional developer, a toner film is formed on the carrier surface by mechanical collisions such as collisions between particles or collisions between particles and a developing device or heat generated by these collisions, so-called spent occurs, and further, toner particles are formed. Of the carrier, the charging characteristic of the carrier deteriorates with use time, and it is necessary to replace the entire developer.

In order to prevent such spent and to always obtain a stable charge amount during use for a long period of time, a method of coating the carrier surface with various resins has been proposed, but it is still satisfactory. Has not been obtained.

Particularly, in a toner for an electrophotographic copying machine intended for high-speed copying, a large amount of a low-molecular-weight polymer is used so as to achieve a reliable fixing property, and it is stronger in a high-speed developing apparatus. The developer is liable to deteriorate due to spent and fine toner due to mechanical collision or the like.

Furthermore, in high-speed copying, the number of copies increases and the toner consumption per machine increases. Therefore, it is desirable to prevent the deterioration of the developer and to reduce the number of maintenance operations for replacing the entire developer. Mareta.

Even if the required properties are only the fixing property and the non-offset property, it is not sufficient that the binder resin simply contains a high molecular weight polymer and a low molecular weight polymer. In addition, it is necessary that these polymers be compatible with each other and be contained in the binder resin in a state of being completely integrated with each other. For example, when the toner is manufactured, stored, or image-formed. It is required that they are not separated.

This is because the fixing property of the low molecular weight polymer and the non-offset property of the high molecular weight polymer are simultaneously exhibited only in such a state. This is because the intended effect cannot be obtained as a toner because the individual effects are exhibited.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and aims at non-offset properties, fixing properties, pulverizability during production, and resistance to storage. An electrostatic image developing toner having good properties in blocking properties (non-aggregating properties) and developability during image formation.
To provide.

Another object of the present invention is to provide a developer containing a carrier, the surface of which is coated with a resin, while maintaining a high effect of preventing the developer from deteriorating the toner and miniaturizing the toner. The present invention provides an electrostatic latent image developer that has a narrow charge amount distribution even when used for a long time, and is free from generation of reverse charging toner, deterioration of image quality, and background contamination.

Another object of the present invention is to provide a developer capable of always forming a stable image by suppressing a change in toner charge due to an environmental change, for example, a humidity change. Generally, the charge amount is high when the humidity is low and becomes low when the humidity is high, thereby changing the quality of the image. However, the developer of the present invention has improved such disadvantages.

[0016]

According to the present invention, there is provided a toner for developing an electrostatic image mainly comprising a binder resin and a colorant, wherein the binder resin has a THF-insoluble content of more than 70% and more than 98%.

(A) GPC molecular weight peak Lp is 4 × 10 ³ to 2 × 10 ⁴
And the weight average molecular weight (Mw) / number average molecular weight (Mn),
A styrene-based copolymer having a molecular weight of less than 3.5,

(B) GPC molecular weight peak (Mp) is 3 × 10 ^{4 to} 5 ×
10 and in molecular weight polymer is a styrene copolymer is ⁵

(C) a high molecular weight polymer which is a crosslinked styrenic copolymer;

The low molecular weight polymer (a) is 65 to 90 per total of the low molecular weight polymer (a) and the high molecular weight polymer (c).
Lp <Mp by weight and the high molecular weight polymer (c) is 35 to 10 parts by weight (provided that the total of the low molecular weight polymer (a) and the high molecular weight polymer (c) is 100 parts by weight). Yes,

The insoluble infusible high molecular weight polymer (c) 100
To provide a toner for developing an electrostatic image, wherein the medium molecular weight polymer (b) is 5 to 60 parts by weight with respect to parts by weight,

A toner for developing an electrostatic image, wherein the acid value of the binding resin is 0.1 to 2.0 KOH mg / g, is preferable.
The binder resin is obtained by polymerizing a low molecular weight polymer (a) and a medium molecular weight polymer (b) by a suspension polymerization method, dissolving in a monomer, and then polymerizing the high molecular weight polymer (c). A toner for electrostatic image development characterized by being a mixed resin in which a low molecular weight polymer (a), a medium molecular weight polymer (b) and a high molecular weight polymer (c) are uniformly compatible and dispersed, The polymer (c) is more preferably an insoluble and infusible polymer (c),

Further, a toner for developing an electrostatic image, wherein the toner for developing an electrostatic image is suitable for a developer using a carrier having a resin coating layer, is preferable.

As described above, the toner for developing an electrostatic image according to the present invention has a lower minimum temperature at which the toner can be fixed and good fixability as compared with the conventional toner, and has excellent non-offset without impairing the toner. With good resistance to blocking, good pulverizability during production, good triboelectricity, and excellent developability.Moreover, the developer using a carrier having a resin coating layer is less likely to deteriorate the developer. It has excellent performance that is unlikely to occur and has great durability when used repeatedly.

The styrene-based component serving as the structural unit of the binding resin is a so-called styrene-based monomer, and specific examples thereof include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and α. -Methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene , Pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,
Examples thereof include 4-dichlorostyrene, and among them, styrene is most preferable.

What gives the first acrylic component and the second acrylic component that constitute the binding resin together with the styrene component is a so-called acrylic monomer, and specific examples thereof include alkyl acrylate and alkyl acrylate. Examples of the alkyl methacrylate include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and methacrylic acid. Examples thereof include lauryl acrylate and stearyl methacrylate, and particularly preferred are n-butyl acrylate, ethylhexyl acrylate, n-butyl methacrylate, and lauryl methacrylate.

The acrylic component may have a glass transition temperature in the range of 40 ° C. to 80 ° C. of a copolymer obtained by polymerizing the acrylic component with the monomer of the styrene component under ordinary conditions. Preferably, and more preferably, the glass transition temperature is in the range of 50C to 70C. However, the glass transition temperature of the medium molecular weight polymer (b) is not limited to this.

The “insoluble and infusible” of the insoluble and infusible high molecular weight polymer (c) as a preferred example of the binder resin is “insoluble” and refers to “infusible”. The term "insoluble" used herein refers to AFTM-407-02 (automotive paint test method, USA). A resin press-molded test piece is wrapped with a 300-mesh wire net and heated in acetone for 7 hours under reflux to insoluble resin. 90% or more by weight, preferably 95% by weight
% Or more, while “infusible” means that the above acetone-insoluble resin component has a diameter of 0.5% when a 10 kg load is applied at 200 ° C. with a descending flow tester (manufactured by Shimadzu Corporation). × 1m
/ m nozzle means that the amount melted for the first minute is less than 1 mm.

The high molecular weight polymer (c) has a crosslinking agent as a component. Such a crosslinking agent is mainly a compound having two or more polymerizable double bonds, such as divinylbenzene and divinylbenzene. Aromatic divinyl compounds such as naphthalene,
Ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3 butanediol
Diethylenic carboxylate such as dimethacrylate, 1,6 hexanediol diacrylate, aryl methacrylate, and the like, N, N-divinylaniline, divinyl ether, divinyl sulfide and the like. Divinylbenzene, ethylene glycol dimethacrylate, and 1,6 hexanediol diacrylate are preferably used.

The amount of the crosslinking agent is preferably from 0.01 to 2% by weight of the monomers constituting the high molecular weight polymer (c), more preferably from 0.02 to 1% by weight, particularly preferably Those having a content of 0.04 to 0.8% by weight are preferably used.

Particularly, as the high molecular weight polymer (c), it is necessary to form a matrix with the low molecular weight polymer (a) and the medium molecular weight polymer (b), so that a crosslinked high molecular weight polymer is preferably used. In the synthesis reaction of the polymer, a very small amount of an initiator or a polyfunctional initiator is suitably used.

The low molecular weight polymer (a) used in the present invention
Is 50 to 100% by weight of styrene, and 50 to 50% by weight of alkyl acrylate and / or alkyl methacrylate.
A styrene-based polymer containing 0% by weight as a monomer unit, and particularly preferred examples are 70 to 95% by weight of styrene.
And 30 to 5% by weight of n-butyl acrylate.

The medium molecular weight polymer (b) is styrene 30 to 9
A styrene-based polymer containing 0% by weight and 70 to 10% by weight of an alkyl acrylate and / or an alkyl methacrylate as monomer units, and a particularly preferred example is 50 to 90% by weight of styrene. % And acrylic acid n
Butyl is 50 to 20% by weight.

The high-molecular-weight polymer (c) contains 50 to 1 styrene.
Containing, as monomer units, 00% by weight, and 50 to 0% by weight of an alkyl acrylate and / or alkyl methacrylate and 0.01 to 2% by weight of a crosslinking agent (the sum of the three becomes 100% by weight). Particularly preferred examples are 60 to 90% by weight of styrene, 5 to 20% by weight of n-butyl methacrylate, and 3 to 50% by weight of n-butyl acrylate.
0 to 10% by weight and crosslinking agent 0.01 to 2% by weight (the sum of the four
0% by weight).

The low molecular weight polymer (a) is 65 to 90 parts by weight, and the high molecular weight polymer (c) is 35 to 10 parts by weight (provided that the low molecular weight polymer (a) and the high molecular weight polymer (c Is preferably in the range of 100 parts by weight), more preferably
The low-molecular-weight polymer (a) is preferably 70 to 85 parts by weight and the insoluble and infusible high-molecular-weight polymer (c) is preferably 30 to 15 parts by weight,
And, based on 100 parts by weight of the insoluble infusible high molecular weight polymer (c), the medium molecular weight polymer (b) is preferably in the range of 5 to 50 parts by weight, more preferably the medium molecular weight polymer (b ) Is 10-40
The parts by weight are preferably used.

When the amount of the low molecular weight polymer (a) is less than 65 parts by weight (the amount of the high molecular weight polymer (c) is more than 35 parts by weight), the offset resistance is good, but the fixability in a low temperature region is poor, and the fixing is performed. The lower limit temperature is undesirably increased. When the amount of the low molecular weight polymer (a) is more than 90 parts by weight (the amount of the high molecular weight polymer (c) is less than 10 parts by weight), the fixing property is good, but hot offset easily occurs, and the fixing temperature range Is unfavorably reduced.

The above low molecular weight polymer (a) and high molecular weight polymer
It is difficult to obtain the desired effect only by satisfying the preferred range of (c), and the low molecular weight polymer (a) is obtained by using the medium molecular weight polymer (b).
It is more preferable that the resin is filled with a mixed resin in which the polymer (b) and the high molecular weight polymer (c) are uniformly compatible and dispersed.

When the amount of the medium-molecular-weight polymer (b) is less than 5 parts by weight based on 100 parts by weight of the high-molecular-weight polymer (c), the fixing property is good, but hot offset tends to occur, The fixing temperature range becomes narrow, which is not preferable. Further, the obtained toner becomes brittle, and tends to be spent on the carrier and miniaturize the toner. When the toner is used for a long period of time, toner scattering from the carrier and toner fogging in a blank space increase.

When the amount of the medium-molecular-weight polymer (b) is more than 60 parts by weight with respect to 100 parts by weight of the high-molecular-weight polymer (c), the offset resistance is good, but the fixability in the low-temperature region is poor. The minimum fixing temperature rises, which is not preferable.

The GPC molecular weight peak Lp of the low molecular weight polymer (a) is
4 × 10 ^{3 to} 5 × 10 ⁴ , preferably 4 × 10 ³ to 2 × 10 ⁴ , more preferably 5 × 10 ^{3 to} 1.5 × 10 ⁴ and the weight average molecular weight (Mw) of the low molecular weight polymer (a) ) / A number average molecular weight (Mn) of less than 3.5 is preferably used.

The GPC molecular weight peak Lp of the low molecular weight polymer (a) is
If it is lower than 4 × 10 ³ , the fixability is good, but the toner tends to cause spent and miniaturization in the developing machine, and the life of the developer is short. On the other hand, when the molecular weight peak Lp is higher than 5 × 10 ⁴ , spent and miniaturization are unlikely to occur, but the fixability in a low temperature region is poor, the minimum fixing temperature rises, and the cold offset temperature also increases. It is not preferable because it is defective.

The GPC molecular weight peak Mp of the medium molecular weight polymer (b) is
3 × 10^Four~ 5 × 10^FivePreferably, 5 × 10^Four ~ 5 × 10^Five, Even more preferred
Or 8 × 10^Four~ 4 × 10^FiveAre preferably used.

The GPC molecular weight peak Mp of the medium molecular weight polymer (b) is
If it is lower than 3 × 10 ⁴ , the fixing property is good, but hot offset is apt to occur, and the fixing temperature range is undesirably narrow. Furthermore, low molecular weight polymer (a) and high molecular weight polymer
The low molecular weight polymer (a) and the high molecular weight polymer are thought to be due to the splicing effect of the medium molecular weight polymer on the compatibility with (c).
Since each polymer of (c) exerts an individual action, the obtained toner becomes brittle, and tends to be spent on the carrier and to make the toner finer. Toner scattering and toner fogging in margins increase. If the GPC molecular weight peak Mp of the medium molecular weight polymer (b) is higher than 5 × 10 ⁵ , the offset resistance is good, but the fixability in the low temperature region becomes poor, and the fixing lower limit temperature increases, which is not preferable.

The GPC molecular weight peak of the low molecular weight polymer (a)
It is necessary that the GPC molecular weight peak (Mp) of the medium molecular polymer (b) is higher than the peak (Lp) (Lp <Mp), and if Lp> Mp, the relationship between the medium molecule and the low molecule is low. It tends to be reversed, and the offset resistance and durability tend to be inferior.

Further, those having a medium molecular weight polymer (b) having a glass transition temperature (Tg) of 0 ° C. to 70 ° C. and a softening point of a falling type flow tester of 80 ° C. to 160 ° C. are preferably used. It is more preferable that the Tg is 20 ° C to 55 ° C and the softening point is 90 ° C to 150 ° C.
Are preferably used.

When the Tg is higher than 70 ° C. and the softening point is higher than 160 ° C., the offset resistance is good, but the fixability in a low temperature region tends to be poor, and the lower limit of fixing temperature tends to increase, which is not preferable. There is. When the Tg is lower than 0 ° C. and the softening point is lower than 80 ° C., the fixing property is good, but hot offset tends to occur easily, and the fixing temperature range tends to be narrow. Further, the preservability of the toner tends to deteriorate.

If the acid value is lower than 0.05 KOH mg / g, it is considered that the resistance of the resin which is the main component of the toner is high, but the charging characteristics of the carrier and the toner change with the use time, and stable development is achieved. There is a tendency that the agent cannot be obtained. Also, the acid value
If it is more than 2.0 KOHmg / g, the polarity of the resin becomes large, and it tends to be difficult to obtain a desired charge amount of the carrier and the toner. Preferably, the acid value is 0.1 to 2.0 KOHmg
/ G is preferably used.

The toner for developing an electrostatic charge image obtained by the present invention is obtained by a resin coating layer in a developing method using a so-called two-component developer in which a carrier made of iron powder or glass beads is mixed with the toner. It is suitably used for a developer using a carrier having the following formula.

Further, the toner of the present invention is not limited to a two-component developer, but may be a one-component developer using no carrier, for example, a magnetic one-component toner containing magnetic powder in the toner. Also, the present invention can be applied to a non-magnetic one-component toner containing no magnetic powder in the toner.

As a carrier having a resin coating layer, a carrier obtained by coating the surface of core particles made of iron, nickel, ferrite or glass beads with a coating layer of an insulating resin is typical. As a resin material, generally, a fluorine resin, a silicone resin, an acrylic resin,
Styrene acrylic copolymer resins, polyester resins, and polybutadiene resins are typical.

When a developer containing the toner for developing an electrostatic image obtained by the present invention and a carrier having a resin coating layer is used, spent particles which adhere to the toner particles on the surface of the carrier particles and are contaminated. It is particularly suitable for a high-speed electrophotographic machine in that the frictional charge characteristics between the carrier and the toner can be controlled and the durability is excellent and the service life is long.

The main component resin of the binder resin of the toner of the present invention can be synthesized, for example, by the following method. That is, after generally synthesizing a low molecular weight polymer (a) and a medium molecular weight polymer (b) by a generally known polymerization method, that is, a bulk polymerization method, a suspension polymerization method, a solution polymerization method, and the like, These polymers can be dissolved in a monomer to be polymerized into a high molecular weight polymer (c), and then this mixture can be synthesized by a suspension polymerization method.

The feature of the above synthesis method is that during the synthesis process, the low molecular weight polymer (a), the medium molecular weight polymer (b) and the high molecular weight polymer (c) are uniformly mixed, (b)
Is that the three polymers of the low-molecular-weight polymer (a) and the high-molecular-weight polymer (c) are completely integrated.

A mixed resin in which three polymers of a low molecular weight polymer (a), a medium molecular weight polymer (b), and a high molecular weight polymer (c) are uniformly compatible and dispersed is described as "gel content" Estimation method ".

The "method for estimating the gel content" means that a polymer component which has been crosslinked into a solvent (for example, insoluble and infusible) in a resin composition has a low molecular weight polymer in a mixed resin. When a matrix is combined with a medium-molecular-weight polymer and affects the dissolution rate of the soluble component, the polymerization rate of the polymer component that has become soluble in the solvent by extraction for a certain period of time is determined, so that the three polymers can be dissolved. It can be used as a parameter indicating the degree of the state of uniform miscible dispersion. The value measured by the following method is defined as tetrahydrofuran (hereinafter abbreviated as THF) insoluble matter.

That is, about 1 g of the resin was weighed (W
₁ [g]), put in a thimble filter paper (No. 86R made by Toyo Roshi Kaisha), apply to a Soxhlet extractor, extract with 100 to 200 ml of THF as a solvent for 6 hours, and concentrate the soluble components extracted by the solvent. After drying at 100 ° C. for several hours, the amount of the soluble resin component is weighed (W ₂ [g]) and calculated according to the following equation.

THF-insoluble content = (W ₁ -W ₂ ) / W ₁ × 100 [%] In the mixed resin obtained by uniformly dispersing the three polymers obtained in the present invention, the THF-insoluble content is 70%. More than 98%, preferably 75-95% is suitably used.

If the THF-insoluble content is lower than 70%, the homogeneously compatible dispersion state is poor, hot offset is likely to occur, and the fixing temperature range is undesirably narrow. On the other hand, if the THF-insoluble content is higher than 98%, the crosslinking density becomes too high, and the fixability becomes poor, which is not preferable.

The toner for developing an electrostatic image according to the present invention is also provided.
In addition, a suitable pigment or dye is blended as a colorant, and if necessary, a charge control agent and other types of toner additives such as a releasing agent and a magnetic substance can be blended to improve fluidity. An external additive such as a cleansing agent or a cleaning aid can be applied to the toner surface.

In addition to the main binder resin, other styrene resins, polyester resins, etc. may be blended and used as an auxiliary resin.
% By weight or less is preferred.

The toner is prepared by mixing the above additives with the main resin component, uniformly mixing and melting, cooling the melted mixture, pulverizing the melted mixture as required, and then pulverizing the mixture with a jet mill or the like, and then classifying the mixture with a classifier. Thereby, a final product (toner) having a desired particle size distribution having an average particle size of 3 to 30 μm can be obtained.

Each test method used in the present specification is described below. [Molecular Weight Measurement Method] The molecular weight at the peak position of the molecular weight distribution was determined by using a gel permeation chromatography (GPC) equipped with a column (3 GMHs manufactured by Tosoh Corporation) using tetrahydrofuran (THF). ) Was dissolved at a concentration of 0.2 wt%, and measurement was performed at a temperature of 20 ° C. at a flow rate of 1 ml / min. When measuring the molecular weight of the sample, a measurement condition was selected in which the logarithm of the molecular weight and the count number of the calibration curve prepared from several types of monodisperse polystyrene standard samples were linear.

[Acid Value Measurement Method] A resin sample (400 mg) was weighed, added with acetone (50 ml) and dissolved in an N ₂ gas atmosphere, and then phenol-phthalene indicator solution (1% ethyl alcohol solution) was added to the solution.
Two drops were added, and titration was performed with 1 / 100N N ₂ OH in an N ₂ gas atmosphere, and the acid value was calculated from the following equation.

Acid value [KOHmg / g] = [(x−B) × f × 56.11
× 0.01] ÷ Sample collection amount f: Factor of 1 / 100N N ₂ OH specified solution-x: Sample titer [ml] B: Blank test titer [ml]

[Measurement method of softening point] 1 g of a resin sample was weighed and measured with a Shimadzu flow tester CFT500 under the conditions of a nozzle 1 × 10 mm, a load of 30 kg, and a temperature rising rate of 3 ° C./min, and flow was started. The temperature at the midpoint of the distance from to the end was taken as the softening point.

[Glass Transition Point (Tg)] The measurement was carried out using a differential scanning calorimeter, Shimadzu DSC-30, in a N ₂ gas atmosphere at a heating rate of 10 ° C./min, and the shoulder was defined as Tg.

[Copy Test] Fixability Test (Offset Property and Minimum Fixing Temperature) A commercially available electrophotographic copying machine was modified (the photosensitive member was an Se-based photosensitive member, the rotation speed of the fixing roller was 500 mm / sec, The image formation was performed using a heater in which the heat roller temperature in the fixing device was made variable and the oil coating device was removed. Fixing temperature 120 ℃
The temperature was controlled to about 230 ° C., and the fixing property and offset property of the image were evaluated.

Here, the minimum fixing temperature means that the bottom surface is swaged.
A load of 500 g was placed on the fastness tester covered with the cover, and the image fixed through the fixing device was rubbed five times back and forth, and before and after rubbing, the optical reflection density was measured with a Macbeth reflection densitometer. Means the temperature of the fixing roller when the fixing rate exceeds 70%.

Fixing rate = (image density after rubbing / image density before rubbing) × 100% Further, as a paper rubbing test, a half-tone fixed image portion was rubbed with paper to obtain a fixed image. The temperature of the fixing roller when there is no stain.

Fogging on Paper In the copying test, the fogging of the toner on the background (margin) was measured using a Minolta CR-200 colorimeter. When the fog is small, the value is 0.5% or less, and when the fog is large, the value is 1% or more.

Storage Stability Regarding the storage stability, the degree of agglomeration when each toner was allowed to stand in a thermostat at 50 ° C. for 24 hours was evaluated.

[Medium molecular weight polymer (b), Production Example-1] styrene (st) 7.3 kg butyl acrylate (BA) 2.7
kg, 22 g of benzoyl peroxide and mixed and dissolved.
20 kg of an aqueous solution of deionized water in which 10 g of polyvinyl alcohol (gothanol KH-17) was dissolved was added, and the inside of the polymerization machine was heated to 85 ° C. with stirring and the polymerization reaction was carried out for 10 hours to obtain a molecular weight peak. A medium molecular weight polymer having a glass transition point (hereinafter, abbreviated as Tg) of 54 ° C and a softening point of 142 ° C was obtained at 26 × 10 ⁴ .

[Medium molecular weight polymer (b), Production Example-2] 6.3 kg of styrene, 3.7 kg of butyl acrylate and 15 g of benzoyl peroxide were charged into a 50-liter polymerization machine and mixed and dissolved. 20 kg of an aqueous solution of deionized water in which 10 g of phenol KH-17 was dissolved, and the inside of the polymerization machine was heated to 90 ° C. with stirring to carry out a polymerization reaction for 10 hours to give a molecular weight peak of 35 × 10 5
^{In 4} , a medium molecular weight polymer having a Tg of 30 ° C. and a softening point of 115 ° C. was obtained.

[Medium molecular weight polymer (b), Production Example-3] 6.8 kg of styrene, 3.2 kg of butyl acrylate and 31 g of benzoyl peroxide were charged and mixed and dissolved in a 50-liter polymerization machine, and then mixed with polyvinyl alcohol (go). -Kenol KH-17) was added with 20 kg of an aqueous solution of deionized water in which 10 g was dissolved, and the inside of the polymerization machine was heated to 90 ° C. with stirring to carry out a polymerization reaction for 10 hours to give a molecular weight peak of 19 × 10 5
^{In 4} , a medium molecular weight polymer having a Tg of 41 ° C. and a softening point of 122 ° C. was obtained.

[Medium molecular weight polymer (b), Production Example-4] 7.0 kg of styrene and 3.0 kg of butyl acrylate and 65 g of benzoyl peroxide were charged into a 50 liter polymerization machine, mixed and dissolved, and then polyvinyl alcohol (go). 20 kg of an aqueous solution of deionized water in which 10 g of phenol KH-17 was dissolved, and the inside of the polymerization machine was heated to 90 ° C. with stirring to carry out a polymerization reaction for 10 hours to give a molecular weight peak of 12 × 10
^{In 4} , a medium molecular weight polymer having a Tg of 47 ° C and a softening point of 123 ° C was obtained.

[0076]

Example 1 A 50 liter polymerization machine was charged with 8.6 kg of styrene (st), 1.4 kg of butyl acrylate (BA), and 600 g of benzoyl peroxide, mixed and dissolved, and then mixed with polyvinyl alcohol (Gothenol KH). -17) 20 kg of aqueous solution of 10 g of deionized water
The polymerization reaction was conducted for 10 hours by heating the inside of the polymerization machine to 140 ° C. with stirring to obtain a low molecular weight polymer having a molecular weight peak of 11,000.

Subsequently, in a 50-liter polymerization machine, 7.59 kg of the low-molecular-weight polymer, 0.69 kg of the medium-molecular-weight polymer of Production Example 1, 1.34 kg of styrene (st), 0.17 kg of butyl acrylate (BA), and methacrylic acid Butyl (BMA) 0.21 kg, divinylbenzene 1.6
g, Kayaester HTP (Di-t-butyl peroxy-hexahydrote
4g of rephthalate), mixed and dissolved, and then 20 kg of an aqueous solution of deionized water in which 10 g of gohsenol KH-17 was dissolved.
Was added, and the inside of the polymerization machine was heated to 85 ° C. with stirring, and the polymerization reaction was carried out for 12 hours.

The obtained polymer slurry was subjected to dehydration, washing and drying as usual post-treatments to obtain a beaded Lp11,0.
00, Mw / Mn = 2.4 low molecular weight polymer (a) 81.5 parts, insoluble infusible high molecular weight polymer (c) 18.5 parts, and 100 parts of high molecular weight polymer, medium molecular weight polymer (b ) 40 parts of a homogeneously miscible mixed resin were obtained.

(Confirmation of Insoluble Infusible High Molecular Weight Polymer of Preferred Example) Separately, only the above high molecular weight polymerization reaction was conducted in a similar polymerization machine, ie, 1.34 kg of styrene, 0.17 kg of butyl acrylate, and butyl methacrylate. 0.12 kg, 2 g of 1-6 hexanediol diacrylate, 3.9 g of Kayaester HTP were mixed and dissolved, and then 20 kg of an aqueous solution of deionized water in which 10 g of gothenol KH-17 was dissolved. In addition, it reacted similarly. The obtained polymer had an insoluble content of 96% in the test of AFTM-407-02 and an insoluble infusible high molecular weight of 0.9 mm in the descending flow tester test. It was united.

100 parts by weight of the mixed resin uniformly dispersed and dispersed, 6 parts by weight of carbon black (MA-100), 2 parts by weight of polypropylene wax (550P), and 2 parts by weight of a metal-containing dye (S-34) Part was pulverized and mixed with a ball mill, and then heated with a hot roll at 140 ° C for 30 minutes.
Kneaded well for a minute.

After cooling, the mixture was roughly crushed by a hammer mill and then finely crushed by a jet mill. Further, the obtained finely pulverized powder is classified with an air classifier to obtain particles of 5 to 20 μm, and then 0.2 parts by weight of hydrophobic silica (R-972) is added and mixed, and toner having an average particle diameter of 10 μm is added. -Was obtained.

When a copying test was conducted with a commercially available copying machine using the toner and the silicon resin-coated carrier, the image could be fixed from 145 ° C. and even at 230 ° C. due to the offset of the toner to the heat fixing roll. There was no stain and even after copying 100,000 sheets, no toner spent on the carrier, and a clear image free of stain and fog was obtained as in the initial stage. Other test results are shown in Table 1. All parts are by weight.

(Measurement of THF Insoluble Content) The mixed resin obtained in Example 1 had a THF insoluble content of 80.2%, and was a mixed resin which was uniformly compatible and dispersed.

[0084]

Example 2 A 50 liter polymerization machine was charged with 8.6 kg of styrene, 1.4 kg of butyl acrylate and 800 g of benzoyl peroxide, mixed and dissolved, and then mixed with polyvinyl alcohol (Gothenol KH).
-17) Add 20 kg of an aqueous solution of deionized water in which 10 g is dissolved, and heat the inside of the polymerization machine to 140 ° C with stirring to carry out the polymerization reaction for 10 hours to obtain a low molecular weight polymer (a) having a molecular weight peak of 8,000. Was.

Subsequently, in a 50-liter polymerization machine, 7.42 kg of the low-molecular-weight polymer (a) and 0.4% of the medium-molecular-weight polymer (b) in Production Example-2 were added.
3 kg, 1.61 kg of styrene, 0.32 kg of butyl acrylate, 0.22 kg of butyl methacrylate, 3.2 g of 1-6 hexanediol diacrylate, and 6.6 g of Kayaester HTP were mixed and dissolved. The reaction was carried out in the same manner as in Example 1 by adding 20 kg of an aqueous solution of deionized water in which 10 g of KH-17 was dissolved.

The resulting polymer was a beaded Lp8000, Mw / M
77.5 parts of low molecular weight polymer (a) with n = 2.6, AFTM test insolubles 97
%, Insoluble infusible high molecular weight polymer (c) 22.5%
Parts, and 100 parts by weight of high molecular weight polymer to medium molecular weight polymer
(b) 20 parts of a mixed resin which was uniformly miscible and dispersed was obtained. A toner was obtained by using the above mixed resin in the same manner as in Example 1, and the test results are shown in Table 1.

[0087]

Example 3 A 50 liter polymerization machine was charged with 9.0 kg of styrene, 1.0 kg of butyl acrylate and 1,000 g of benzoyl peroxide, mixed and dissolved, and then mixed with polyvinyl alcohol (Gothenol).
KH-17) 20 kg of an aqueous solution of deionized water in which 10 g was dissolved was added, and the inside of the polymerization machine was heated to 140 ° C. with stirring to carry out a polymerization reaction for 10 hours to obtain a low molecular weight polymer having a molecular weight peak of 6,000.

Subsequently, 7.04 kg of the low molecular weight polymer (a) and 0.29 kg of the medium molecular weight polymer (b) of Production Example-3 were placed in a 50 liter polymerization machine.
And styrene 2.06 kg butyl acrylate 0.35 kg, butyl methacrylate 0.26 kg, 1-6 hexanediol-diacrylate 2.9 g, and benzoyl peroxide 2.7 g were mixed and dissolved. The reaction was carried out in the same manner as in Example 1 by adding 20 kg of an aqueous solution of deionized water in which 10 g of -17 was dissolved.

The obtained polymer was a bead-like Lp6000, Mw / M
72.5 parts of n = 2.3 low molecular weight polymer (a), AFTM test insolubles 96
%, Insoluble and infusible high molecular weight polymer (c) 27.5
Parts, and 100 parts by weight of high molecular weight polymer to medium molecular weight polymer
(b) 11 parts of a mixed resin that was uniformly miscible and dispersed was obtained. A toner was obtained by using the above mixed resin in the same manner as in Example 1, and the test results are shown in Table 1.

[0090]

EXAMPLE 4 A 50-liter polymerization machine was charged with 8.3 kg of styrene, 1.0 kg of butyl acrylate, 0.7 kg of butyl methacrylate, and 800 g of benzoyl peroxide, mixed and dissolved, and then mixed with polyvinyl alcohol (goshenol). KH-17) 20 kg of an aqueous solution of deionized water in which 10 g was dissolved was added, and the inside of the polymerization machine was heated to 140 ° C. with stirring to carry out the polymerization reaction for 10 hours, and the molecular weight peak was 8,000.
Was obtained as a low molecular weight polymer (a).

Subsequently, 7.69 kg of the low-molecular-weight polymer and 0.39 kg of the medium-molecular-weight polymer (b) of Production Example-4 were placed in a 50-liter polymerization machine.
And styrene 1.48 kg butyl acrylate 0.34 kg, butyl methacrylate 0.1 kg, ethylene glycol dimethacrylate 3.9 g, Kayaester HTP 4.4 g, and mixed and dissolved.Gosenol KH-17, 10 g The reaction was carried out in the same manner as in Example 1 by adding 20 kg of an aqueous solution of deionized water in which was dissolved.

The obtained polymer was a bead-like Lp8000, Mw / M
80 parts of low molecular weight polymer with n = 2.8, 98% insoluble matter in AFTM test, 20 parts of insoluble and infusible high molecular weight polymer (c) with 0.5 mm leaching amount, and 100 parts of high molecular weight polymer A mixed resin in which 20 parts of the molecular weight polymer (b) was uniformly miscible and dispersed was obtained. A toner was obtained by using the above mixed resin in the same manner as in Example 1, and the test results are shown in Table 1.

[0093]

Comparative Example 1 A 50-liter polymerization machine was charged with 8.6 kg of styrene, 1.4 kg of butyl acrylate and 600 g of benzoyl peroxide, mixed and dissolved, and then mixed with polyvinyl alcohol (Gothenol KH).
-17) Add 20 kg of an aqueous solution of deionized water in which 10 g is dissolved, and heat the inside of the polymerization machine to 140 ° C. with stirring to carry out a polymerization reaction for 10 hours to obtain a low molecular weight polymer (a) having a molecular weight peak of 11,000. Was.

Subsequently, in a 50 liter polymerization machine, 5.77 kg of the above low molecular weight polymer, 3.85 kg of the medium molecular weight polymer of Production Example 1, 2.96 kg of styrene, 0.89 kg of butyl acrylate, 1-6 hexanediol diacryle -4.6 g, Kayaester HTP
After charging and mixing and dissolving 8.9 g, Gohsenol KH-1
20 kg of an aqueous solution of deionized water in which 7, 10 g were dissolved was added, and the reaction was carried out in the same manner as in Example 1.

The obtained polymer had a beaded Lp of 11,000 and Mw of
/Mn=2.5 low molecular weight polymer 60 parts, AFTM test insoluble content 97%,
A mixed resin in which 40 parts of an insoluble and infusible high-molecular-weight polymer having a melting amount of 0.7 mm and 10 parts of a medium-molecular-weight polymer in 100 parts of a high-molecular-weight polymer were uniformly compatible and dispersed was obtained. Toner was obtained using the above mixed resin in the same manner as in Example 1, and the test results were shown in Table 2.
It writes in.

[0096]

Comparative Example 2 A 50 liter polymerization machine was charged with 8.6 kg of styrene, 1.4 kg of butyl acrylate and 600 g of benzoyl peroxide, mixed and dissolved, and then mixed with polyvinyl alcohol (goseno-).
20 Kg of deionized water aqueous solution in which 10 g of dissolved KH-17 was dissolved, and the inside of the polymerization machine was heated to 140 ° C. with stirring to carry out a polymerization reaction for 10 hours to obtain a low molecular weight polymer having a molecular weight peak of 11,000. .

Subsequently, in a 50-liter polymerization machine, 8.78 kg of the low-molecular-weight polymer, 0.46 kg of the medium-molecular-weight polymer of Production Example 1, 0.593 kg of styrene 0.076 kg of butyl acrylate, 0.091 kg of butyl methacrylate, and dividil After 0.8 g of benzene and 2.3 g of Kayaester HTP were charged and mixed and dissolved, 20 kg of an aqueous solution of deionized water in which 10 g of gothenol KH-17 was dissolved was added, and the reaction was carried out in the same manner as in Example-1. .

The obtained polymer was Lp11,000, M in the form of beads.
w / Mn = 2.7 low molecular weight polymer 92 parts, AFTM test insolubles 96
%, 8 parts of an insoluble and infusible high molecular weight polymer having a melting amount of 0.9 mm, and a mixed resin in which 60 parts of a medium molecular weight polymer was uniformly compatible and dispersed with respect to 100 parts of the high molecular weight polymer. A toner was obtained using the mixed resin in the same manner as in Example 1, and the test results are shown in Table 2.

[0099]

[Comparative Example 3] 8.3 kg of styrene, 1.0 kg of butyl acrylate, 0.7 kg of butyl methacrylate, and 800 g of benzoyl peroxide were charged into a 50-liter polymerization machine, mixed and dissolved, and then polyvinyl alcohol (goshenol) was added. KH-17) 20 kg of an aqueous solution of deionized water in which 10 g was dissolved was added, and the inside of the polymerization machine was heated to 140 ° C. with stirring to carry out the polymerization reaction for 10 hours, and the molecular weight peak was 8,000.
Was obtained.

Subsequently, 8.0 kg of the above low molecular weight polymer, 1.54 kg of styrene and 0.36 k of butyl acrylate were placed in a 50 liter polymerization machine.
g, butyl methacrylate 0.1 kg, 1-6 hexanediol diacrylate 2 g, and Kayaester HTP 6.1 g were mixed and dissolved, followed by dissolving 10 g of gothenol KH-17. The reaction was carried out in the same manner as in Example 1 by adding 20 kg of an aqueous solution of ionized water.

The obtained polymer was a beaded Lp8,000, Mw /
A mixed resin in which 80 parts of a low molecular weight polymer having Mn = 3.1 and 20 parts of an insoluble and infusible high molecular weight polymer were uniformly compatible and dispersed was obtained. A toner was obtained by using the above mixed resin in the same manner as in Example 1, and the test results are shown in Table 2.

[Comparative Example-4] Example with composition and compounding amount shown in Table 2
A mixed resin was obtained in the same manner as in Example 1, and a toner was prepared using the mixed resin. Table 2 shows the test results.

[0102]

Comparative Example -5 6.5 kg of styrene, 3.5 kg of butyl acrylate and 600 g of benzoyl peroxide were charged and mixed and dissolved in a 50 liter polymerization machine, and then polyvinyl alcohol (Gothenol KH) was added.
-17) Add 20 kg of an aqueous solution of 10 g of deionized water,
The inside of the polymerization machine was heated to 140 ° C. with stirring to carry out a polymerization reaction for 10 hours to obtain a polymer having an average molecular weight of 12,000.

In another polymerization machine, 6.5 kg of styrene and 3.5 kg of butyl acrylate were reacted to obtain a polymer having an average molecular weight of 210,000. Further, 6.5 kg of styrene and 3.5 kg of butyl acrylate were reacted in another polymerization machine to obtain a polymer having an average molecular weight of 1,150,000. 60 parts of a polymer having an average molecular weight of 12,000 obtained by the above reaction, 30 parts of a polymer having an average molecular weight of 210,000, and an average molecular weight of 1,1
Toner was obtained in the same manner as in Example 1 by using 100 parts of a polymer mixture obtained by mixing 10 parts of 50,000 polymer, and the test results are shown in Table 2.

[0104]

Comparative Example -6 8.0 g of styrene, 2.0 g of butyl acrylate, 50 g of divinylbenzene, and 500 g of benzoyl peroxide were charged into a 50-liter polymerization machine and mixed and dissolved. Then, polyvinyl alcohol (Gothenol KH-17) was added. ) 20 kg of an aqueous solution of deionized water in which 10 g was dissolved was added, and the inside of the polymerization machine was heated to 85 ° C with stirring to carry out a reaction for 10 hours to obtain a crosslinked polymer. A toner was obtained using the above crosslinked resin in the same manner as in Example 1, and the test results are shown in Table 2.

[0105]

[Table 1]

[0106]

[Table 2]

[0107]

The present invention relates to a toner for developing an electrostatic image formed in an electrophotographic method, an electrostatic printing method, an electrostatic recording method or the like. The toner obtained in the present invention has excellent non-offset properties, fixing properties, pulverizability during production, blocking resistance during storage (non-aggregation), developability during image formation, and its surface is coated with a resin. In a developer containing a carrier, the charge amount distribution is narrow even when used for a long time while maintaining a high effect of preventing the toner from being spent on the toner, and the generation of the oppositely charged toner, the deterioration of the image quality, and the contamination of the background are prevented. It shows excellent physical properties of no.

Claims (4)

(57) [Claims] 1. A toner for developing an electrostatic image mainly comprising a binder resin and a colorant, wherein the binder resin has a THF-insoluble content of more than 70% and 98%, and (a) a GPC molecular weight peak Lp. There and a weight average molecular weight ^{4 × 10 3 ~5 × 10 4} (Mw) / number average molecular weight (Mn), a styrene-based copolymer is less than 3.5 and a low molecular weight polymer (b) GPC molecular weight peak A medium molecular weight polymer which is a styrene copolymer having a Mp of 3 × 10 ^{4 to} 5 × 10 ⁵ and (c) a high molecular weight polymer which is a crosslinked styrene copolymer, The low molecular weight polymer (a) and the high molecular weight polymer (c) per total, the low molecular weight polymer (a) is 65 to 90 parts by weight and the high molecular weight polymer (c) is 35 to 10 parts by weight. Yes (however, the total of the low molecular weight polymer (a) and the high molecular weight polymer (c) is 10
0 parts by weight) Lp <Mp and the high molecular weight polymer
(c) A toner for developing an electrostatic image, wherein the medium molecular weight polymer (b) is 5 to 60 parts by weight based on 100 parts by weight. 2. The toner for developing an electrostatic image according to claim 1, wherein the polymer (c) is an insoluble and infusible polymer (c). 3. The toner for developing electrostatic images according to claim 1, wherein the acid value of the binder resin is 0.05 to 2.0 KOH mg / g. 4. An electrostatic image developing toner comprising a binder resin and a colorant as main components, wherein the binder resin is formed from a low molecular weight polymer (a) and a medium molecular weight polymer (b) by a suspension polymerization method. A low molecular weight polymer (a), a medium molecular weight polymer (b), and an insoluble infusible polymer obtained by polymerizing and dissolving in a monomer and then polymerizing the insoluble insoluble high molecular weight polymer (c). Polymer
(c) is a mixed resin uniformly dispersed and compatible, and (a) G
A low molecular weight polymer which is a styrene copolymer having a PC molecular weight peak Lp of 4 × 10 ^{3 to} 5 × 10 ⁴ and a weight average molecular weight (Mw) / number average molecular weight (Mn) of less than 3.5; (b) Medium molecular weight polymer which is a styrene copolymer having a GPC molecular weight peak (Mp) of 3 × 10 ^{4 to} 5 × 10 ⁵ and (c) high molecular weight which is a crosslinked styrene copolymer Containing the polymer, the low molecular weight polymer (a) and the high molecular weight polymer (c) per total of 65 to 90 parts by weight of the low molecular weight polymer (a) and the high molecular weight polymer (c ) Is 35 ~
10 parts by weight (however, the total of the low molecular weight polymer (a) and the high molecular weight polymer (c) is 100 parts by weight) and Lp <Mp, and 100 parts by weight of the high molecular weight polymer (c) A toner for developing an electrostatic image, wherein the content of the medium molecular weight polymer (b) is 5 to 60 parts by weight.