JP2681785B2 - Binder resin for toner and toner - Google Patents

Description

The present invention relates to a toner binder resin for a toner using a dry developer used in electrophotography, electrostatic recording, magnetic recording and the like, and a binder resin for the toner. Relates to a toner using.

[Prior Art] Conventionally, a number of methods are known as electrophotographic methods, such as US Pat. No. 2,297,691, JP-B-42-23910 and JP-B-43-24748. An electric latent image is formed on the photoconductor by various means using a conductive substance, then the latent image is developed with toner, and the toner image is transferred to a transfer material such as paper as necessary. After that, it is fixed by heating, pressure, heating and pressurizing or solvent vapor to obtain a copy. In addition, when there is a step of transferring the toner image, a step for removing the residual toner is usually provided.

A method of visualizing an electronic latent image using toner is, for example, a magnetic brush method described in U.S. Pat.No. 2,874,063, a cascade developing method described in U.S. Pat. No. 2,618,552, and JP-B 2,221,776. The powder cloud method described in the specification and the method using a conductive magnetic toner described in US Pat. No. 3,909,258 are known.

Conventionally, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have been used as toners applied to these developing methods. For example, particles obtained by finely pulverizing a dispersion of a colorant in a binder resin such as polystyrene to about 1 to 30 μm are used as toner. As the magnetic toner, toner containing magnetic particles such as magnetite is used. On the other hand, in the case of using a so-called two-component developer, the toner is usually used by being mixed with carrier particles such as glass beads and iron powder.

Today, such recording methods are widely used not only for general copying machines but also for computer outputs and microfilm printing. As a result, the required performance becomes higher, and various performances such as smaller size, lighter weight, lower energy, higher speed, more maintenance-free, and more personality are required at the same time. Was. In order to satisfy these requirements, the demands on the toner have become more severe in various aspects. For example, when the size is reduced, a heat source such as a fixing device or an exposure lamp is pushed into a narrow place, so that the temperature inside the device tends to increase. Therefore, the blocking property of the toner must be further improved. In order to reduce the weight, the fixing roller is designed to be thinner and thinner, and the cleaning mechanism of the fixing roller and the cleaning mechanism of the photoconductor are going to be simple and light.
It is a direction in which a coating device such as an oil for preventing offset is not attached to the fixing device. Therefore, it is necessary to improve the fixing property of the toner, the offset resistance, and the cleaning resistance of the photoconductor. Further, in order to achieve lower energy and higher speed, the fixing property of the toner must be naturally improved, and in order to be more personalized, it is necessary to improve the reliability and prevent jamming. Becomes important. Jams often occur when the copy paper is wound around the rollers of the fixing machine, and it is necessary to improve the winding property of the toner on the fixing roller.

In the above example, the demands for the toner are severe, but if these are not improved at the same time, the demands cannot be satisfied. However, there is no point in reducing the developing characteristics such as image quality and toner durability and the toner production efficiency in order to realize these.

Especially in today's copying machines, there is a strong demand for lower energy consumption and higher speeds, and the durability of the machines is also improving.
Long exposure to strong mechanical loads. Therefore, the toner is required to have high durability, which has never been seen before, and moreover, it is necessary to maintain high quality and high resolution for a long period of time.

These performances are largely due to the homogeneity of the toner. In particular, a polyolefin used as a colorant or a fixing aid, and in the case of a magnetic toner, dispersion of these in a toner, such as a magnetic substance containing 30 to 60 wt% of the toner, is a point of high durability.

These are largely due to the performance of the binder resin of the toner. There are proposals to improve these by using a release agent, a plasticizer, and other additives, but these are auxiliary.

Various methods have been proposed for improving the binder resin.

For example, JP-A-56-158340 proposes a toner composed of a low molecular weight polymer and a high molecular weight polymer, which has a low fixing temperature, good offset resistance, and sufficient fixing characteristics. Has not been obtained. Generally, in order to improve the offset resistance, it is necessary to increase the molecular weight of the high molecular weight component or to increase the ratio thereof. In this direction, the fixing temperature tends to increase, and it is difficult to obtain a practically satisfactory one.

Furthermore, for example, Japanese Patent Publication No. 60-20411 discloses a resin composition comprising a low-molecular-weight polymer and a high-molecular-weight polymer, which is obtained by polymerizing a monomer in the presence of a high-molecular-weight polymer. In order to improve the offset resistance, it is necessary to increase the molecular weight of the high molecular weight component or increase the ratio,
Similarly, the fixing temperature tends to be high, and it is difficult to obtain a practically satisfactory one. Further, regarding a toner obtained by blending a low molecular weight polymer and a crosslinked polymer, for example, see JP-A-58
No. 86558 proposes a toner containing a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as main resin components.
According to the method, the fixing property tends to be improved, but the weight average molecular weight / number average molecular weight (Mw / Mn) of the low molecular weight polymer is as small as 3.5 or less, and the insoluble and infusible high molecular weight polymer is Due to the large content of 40 to 90 wt%, it is difficult to satisfy both offset resistance and fixability with high performance. Actually, fixability is only for a fixer with a liquid supply device for offset prevention. It is extremely difficult to produce a toner that sufficiently satisfies the offset resistance.

Further, when the amount of insoluble and infusible high molecular weight polymer increases, the melt viscosity becomes extremely high in the heat kneading at the time of toner preparation, and therefore, it is necessary to heat knead at a temperature much higher than usual or heat knead with a high shear. As a result, the former has a problem that the toner properties are deteriorated by thermal decomposition of other additives, and the latter has a problem that the initial offset resistance performance is difficult to be obtained due to excessive cleavage of the molecules of the binder resin.

Further, it is not easy to disperse the magnetic material, the fixing aid, such as polyolefins in the state where the high-crosslinking component and the low-molecular weight component are mixed as described above, and there may be no problem in the conventional copying apparatus, Considering higher durability, it can be said that it is quite severe.

Further, JP-A-60-166958 discloses a number average molecular weight of 500.
There has been proposed a toner comprising a resin composition obtained by polymerization in the presence of a low molecular weight poly-α-methylstyrene of 1,1,500.

In particular, the publication discloses that the number average molecular weight (Mn) is 9,000 to 30,000.
Although the range of 0 is preferable, the fixing property becomes a practical problem when Mn is increased in order to further improve the offset resistance, and thus it is difficult to satisfy the offset resistance and the fixing property with high performance.

In addition, JP-A-56-16144 discloses that the molecular weight distribution by GPC is such that the molecular weight is 10 ³ to 8 × 10 ⁴ and the molecular weight is 10 ⁵ to 2 × 1.
Toner containing a binder resin component having at least one maximum value has been proposed in each of the regions of 0 ^6. In this case, the offset resistance, the fixability, the filming and fusion adhesion to the photoconductor, the image property, etc. are excellent, but further improvement in the offset resistance and the fixability in the toner is demanded. In particular, it is difficult for the resin to meet today's strict requirements while further improving the fixability and maintaining or improving various other performances.

[Problems to be Solved by the Invention] It is extremely difficult to achieve high performance relating to fixing in this way. Further, in a copy in which the toner is fixed, the copy is often folded in half or in four or the like due to the necessity for storage.

In such bending, the image of the bent portion may be peeled off from the copy to deteriorate the image quality,
It is required to maintain good image quality even for such bending.

As described above, no highly satisfying required items have been proposed yet.

An object of the present invention is to provide a binder resin for a toner which simultaneously satisfies excellent performances in various items and a toner using the resin.

Another object of the present invention is to provide a binder resin for toner which has excellent fixing property and excellent blocking property, and a toner using the resin.

Another object of the present invention is to provide a binder resin for a toner such as a photoreceptor having excellent fusion resistance and a toner using the resin.

Another object of the present invention is to provide a binder resin for toner having good dispersibility such as a colorant, a release agent, especially a magnetic material, and a toner using the resin.

Another object of the present invention is to provide a binder resin for toner which is excellent in developability, especially image quality, durability and bending resistance, and a toner using the resin.

[Means for Solving the Problems] In the present invention, at least one material selected from the group consisting of magnetic fine particles, a colorant, a charge control agent, and a release agent, and a binder resin are mixed and then subjected to a heat kneading step. And a binder resin for a toner used in a toner produced through a crushing step, the binder resin being substantially spherical or an aggregate of spherical particles, and having an average particle diameter of 0.1 to 0.7 mm. A vinyl-based resin particle having a THF-insoluble content of 10% or less in the binder resin.
Less than wt% (based on binder resin), THF of the binder resin
The molecular weight distribution of soluble components by GPC was 10,000.
The following components have a weight W ₁ of 10 to 50% by weight and a molecular weight of 500,
The weight W ₂ of 000 or more components is 5 to 30% by weight, and W ₂ / W ₁
The ratio is 0.05 to 2.0, has a peak in the region of molecular weight 10,000 or less, the glass transition point of the component of molecular weight 10,000 or less
The present invention relates to a binder resin for toner, which has a temperature of 55 ° C. or higher.

The present invention also provides at least one selected from the group consisting of magnetic fine particles, a coloring agent, a charge control agent, and a release agent.
A toner produced by mixing at least one kind of material and a binder resin, and then through a heat kneading step and a pulverizing step, wherein the binder resin is substantially spherical or an aggregate of spherical particles, and its average particle A vinyl resin particle having a diameter of 0.1 to 0.7 mm, and the content of the THF insoluble component of the binder resin is 10
Less than wt% (based on binder resin), THF of the binder resin
The molecular weight distribution of soluble components by GPC was 10,000.
The following components have a weight W ₁ of 10 to 50% by weight and a molecular weight of 500,
The weight W ₂ of 000 or more components is 5 to 30% by weight, and W ₂ / W ₁
The ratio is 0.05 to 2.0, has a peak in the region of molecular weight 10,000 or less, the glass transition point of the component of molecular weight 10,000 or less
The present invention relates to a toner having a temperature of 55 ° C. or higher.

 The configuration of the present invention will be described.

In order to achieve the above-mentioned object at the same time, various binder resins were used, and the constitution and performance thereof were earnestly studied from various angles. As a result, they have found that the ratio of the THF-insoluble matter in the binder resin and the molecular weight distribution of the THF-soluble matter can be achieved with a specific constitution. When the binder resin is dissolved in a solvent such as THF, it can be separated into insoluble and soluble components.
The molecular weight distribution can be measured with C.

The molecular weight distribution of THF-soluble matter, the property of whether the fixing temperature is high or low (hereinafter referred to as fixing property), bending resistance, and blocking resistance were examined. As a result, GP
It was found that the components having a molecular weight of about 10,000 or less in the C molecular weight distribution have different functions from those having a molecular weight of about 10,000 or more. That is, the content ratio W _{1 of the} component having a molecular weight of 10,000 or less with respect to the entire binder resin does not strongly influence the fixing property or the offset resistance as is generally said, but is rather rather within a specific range. It was found that it was not related, but instead was strongly related to grindability.

From other considerations, the binder resin is basically 500,
The content ratio W ₂ of the components of 000 or more mainly affects the offset resistance, wrapping property, and bending resistance, and the component of the THF soluble component having a molecular weight of 10,000 or less is mainly crushability, blocking property, and photoreceptor. It was found that the components having a molecular weight of more than 10,000 soluble in THF influence the fixing property mainly. And molecular weight
The proportion of components of 10,000 or less is preferably 10 to 50 wt%, and more preferably 10 to 39 wt%. In order to obtain sufficient performance, the molecular weight is 10,000 or less and 2,000 or more (preferably 2,0
Has a peak in the region (00-8,000) and has a molecular weight of 15,000-20
A peak or shoulder is required in the area of 0,000 (preferably 20,000 to 150,000). There is no peak at 2,000 to 10,000 and there is a peak at a molecular weight of 2,000 or less, but if the proportion of components with a molecular weight of 10,000 or less exceeds 50 wt%, blocking resistance,
Fusing to the photoconductor, filming, etc. become a little problem.
There is no peak at a molecular weight of 10,000 or less and there is a peak in a region above 10,000, but the proportion of components with a molecular weight of 10,000 or less is 10 wt.
If it is less than%, the grindability becomes a problem, and the formation of coarse particles also becomes a problem.

Further, when there is no peak or shoulder in a region having a molecular weight of 15,000 or more, and there is a peak only in a region having a molecular weight of less than 15,000, the problem of offset resistance becomes a problem. Molecular weight 15,000-200,000
If there are no peaks or shoulders in the area and there is a main peak in the area exceeding 200,000, the pulverizability becomes a problem.

Further, the THF-soluble component needs to satisfy Mw / Mn ≧ 5, and when Mw / Mn is less than 5, the offset resistance and the bending resistance tend to decrease, which causes a problem.

Mw / Mn is preferably 80 or less, more preferably 1
0 ≦ Mw / Mn ≦ 60 is good.

In particular, when Mw / Mn satisfies 10 ≦ Mw / Mn ≦ 60, particularly excellent performance is exhibited in various characteristics such as fixing property, offset resistance, bending resistance, and image quality.

Here, Mw is a weight average molecular weight measured by GPC described later, and Mn is a number average molecular weight obtained by the same measurement.

Further, the content of 500,00 or more of the binder resin of the toner needs to be 5 to 30 wt%. 5wt% of over 500,000 components
If less than this, offset resistance and bending resistance become problems,
If it exceeds 30 wt%, problems such as molecular chain scission and deterioration due to heat kneading during toner production occur. Preferably, the content of the components of 500,000 or more is 5 to 25 wt% in terms of offset resistance and bending resistance.

Furthermore the ratio of W ₂ / W ₁ is required in the range of 0.05 to 2.0. 0.0
If it is less than 5, offset resistance and bending resistance become problems, and if it exceeds 2.0, the fixing temperature becomes high, and deterioration of molecular chains due to thermal kneading during toner production occurs. Preferably, the ratio of W ₂ / W ₁ is good in the range of 0.1 to 2.0.
Further, the THF insoluble content of the toner binder resin must be less than 10% by weight. If the content is more than 10% by weight, a problem arises with respect to bending resistance. Such THF-insoluble matter is preferably less than 5% by weight.

The THF-soluble matter having a molecular weight distribution of less than 10,000 molecular weight component of the glass transition point Tg ₁ and toner overall glass transition point Tg _t of the resin
When Tg ₁ is 55 ° C. or higher and Tg _t is 55 ° C. or higher, the fixing property, bending resistance, fusion-bonding to the photoconductor, filming property, blocking resistance and the like are improved.

Here, Tg ₁ is measured by the following method. At a temperature of 25 ° C., THF is flowed at a flow rate of 7 ml per minute, and a THF sample solution having a concentration of about 3 mg / ml of a THF-soluble component of the toner is injected into a molecular weight distribution measuring device of about 3 ml, and components having a molecular weight of 10,000 or less are introduced. To separate. After fractionation, the solvent was distilled off under reduced pressure and further 90 ° C.
Dry for 24 hours under reduced pressure in an atmosphere. The above operation is repeated until about 20 mg of a component having a molecular weight of 10,000 or less is obtained.
In perform annealing for 48 hours, the Tg was measured by differential scanning calorimetry after this, this value and Tg _1. The measurement at this time was performed according to the generally known ASTM D3418-82 method.

That is, the temperature was raised to 120 ° C. or more by measuring the temperature at 10 ° C./min, held there for about 10 minutes, quenched to 0 ° C., held there for 10 minutes, and then heated at 10 ° C./min. Get the curve. Tg is defined by the intersection of the middle line of the baseline and the inflection curve.

TSKgel G2000H, TSKgel G2500H,
TSKgel G3000H, TSKgel G4000H (both Toyo Soda Kogyo Co., Ltd.) and the like are used. In the present invention, TSKgel G2000H is used.
And TSKgel G3000H were used in combination.

The values of Tg _t is a Tg of the toner 50 ° C. The toner was annealed for 48 hours, determined by the subsequent differential scanning calorimetry.

The most preferred embodiment of the present invention, as shown in FIG.
In the PGC molecular weight distribution of THF-soluble matter, the molecular weight is 15,000 to 20.
The height of the highest peak in the area of 0,000 is h ₂ , the molecular weight is
H ₁ the height of the highest peak in the region of 2,000 to 10,000
Then, the toner contains a binder resin having a ratio of h ₁ / h ₂ of 0.2 to 3.0 / 1. Further, the number average molecular weight of the THF-soluble component is preferably 2,000 ≦ Mn ≦ 9,000. Mn <
If it is 2,000, the offset property and bending resistance become problems, and if it is 9,000 <Mn, the crushability and fixing property become problems.

The THF insoluble content in the present invention refers to the weight ratio of the polymer component (substantially crosslinked polymer) that becomes insoluble in the THF solvent in the resin composition in the toner, and the It can be used as a parameter indicating the degree of crosslinking. The THF-insoluble matter is defined by a value measured as follows.

That is, 0.5 to 1.0 g of a toner sample is weighed (W
₁ g), put in a thimble filter paper (for example, No. 86R manufactured by Toyo Roshi Kaisha), extract with a Soxhlet extractor for 6 hours using 100 to 200 ml of THF as a solvent, and evaporate the soluble components extracted with the solvent. Vacuum drying for several hours at ℃, THF
Weigh the amount of soluble resin component (W ₂ g). The weight of a component other than the resin component such as a magnetic substance or a pigment in the toner is expressed as (W
₃ g). The THF-insoluble content is obtained from the following formula.

In the present invention, the molecular weight of a peak or / and a shoulder of a chromatogram by GPC (gel permeation chromatography) is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40 ° C., and THF (tetrahydrofuran) was passed through the column at this temperature as a solvent at a flow rate of 1 ml per minute, and a THF sample of a resin adjusted to a sample concentration of 0.05 to 0.6% by weight was used. The solution
Inject 50 to 200 μl and measure. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical C
o. or Toyo Soda Kogyo Co., Ltd. with a molecular weight of 6 × 10 ² , 2.1
× 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ ,
Use 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ and at least 1
It is appropriate to use about 0 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

In order to accurately measure the molecular weight region of 10 ³ to 4 × 10 ^6, a plurality of commercially available polystyrene gel columns may be used in combination. For example, μ-styr manufactured by Waters may be used.
agel 500,10 ³ , 10 ⁴ , 10 ⁵ combination and Showa Denko
A combination of Shodex KF-80M and KF-802,803,804,805,
Or TSKgel G1000H, G2000H, G2500H, G3 manufactured by Toyo Soda
A combination of 000H, G4000H, G5000H, G6000H, G7000H, GMH is preferred.

Weight% of the binder resin of the present invention having a molecular weight of 10,000 or less
And the weight% of the binder resin of 500,000 or more, the molecular weight of 1 or less is cut through the molecular weight of 10,000 or less in the chromatogram by GPC.
The weight ratio with the cutout of 000 or more is calculated, and the weight% of the THF insoluble content is used to calculate the weight% with respect to the entire binder resin. W ₂ / W ₁ is indicated by the weight ratio of each component.

The foldability was evaluated by displaying a black image on the entire surface, folding the images so that they overlap each other with a load of about 200 g, and rubbing the images 10 times with a sillbon paper C paper, and rubbing the images with a load of about 200 g. The peeling was represented by the reduction rate (%) of the reflection density.

The resin particles of the present invention are substantially spherical or an aggregate of spherical particles. This is naturally generated to some extent in a polymerization method using a dispersion medium and a dispersoid.
Therefore, the resin powder has an advantage that it has good fluidity and is easy to handle, and unlike the solution polymerization method or the bulk polymerization method, it does not require a step of pulverizing the lumps into fine pieces, and thus has high production efficiency. However, there is a slight problem as a toner material. That is, since the resin powder and other materials such as magnetic fine particles, colorants, charge control agents, and release agents have extremely different fluid specific gravities, there is a problem that they are not sufficiently mixed during powder mixing in the previous stage of heat kneading. Occurs. In the conventionally known binder resin,
In the subsequent step of heat kneading, this can be supplemented to make a toner that can be used normally. It has been found that the resin of the constitution of the present invention is good in normal use, but in view of high durability, the conventional idea is insufficient. That is,
Binder resin, cross-linking component and more than 500,000 components and molecular weight of 10,0
When containing 10 to 50 wt% of a low molecular weight component of 00 or less, it is considered that other materials need to sufficiently enter and disperse into the low molecular weight portion existing in the network of 500,000 or more components and the cross-linking, For that purpose, it is considered necessary to sufficiently homogenize the powder during the powder mixing in the previous step of the heat kneading.

As a result of study, the average particle size of the binder resin becomes bulky and difficult to disperse when the average particle size is smaller than 0.10 mm, and in order to reduce the particle size, a large amount of a dispersant such as polyvinyl alcohol or calcium phosphate is added. Therefore, the electrostatic properties of the toner, especially the environmental properties, tend to deteriorate. Further, if the average particle size of the binder resin is larger than 0.7 mm, dispersion with a magnetic material or the like during powder mixing is poor, and long-term durability becomes a problem. Preferably, the average particle size of the binder resin is 0.15 ~
0.4 mm.

The average particle diameter of the binder resin here is a cumulative 50% by weight value of the distribution obtained by sieving (hereinafter referred to as D50%), and a more preferable embodiment is a cumulative 10% value (hereinafter
D10%) is 0.09 to 0.4 mm, preferably 0.1 to 0.2 m
m, when expressed in the same manner, D20% is 0.12 to 0.5 mm, preferably 0.13 to 0.25 mm, D30% to D50% is 0.15 to 0.7 mm, preferably 0.15 to 0.4 mm, and D60% to D80% is 0.15. ~ 0.8
mm, preferably 0.25 to 0.7 mm, D90% to D100% is 0.
It is 2 to 0.8 mm, preferably 0.5 to 0.8 mm, and the ratio on the 20 mesh is 10 wt% or less, preferably 5 wt% or less.

 The measuring method of this particle distribution is shown below.

Low tap type vibration sieving machine, JIS standard sieve 20,4
2,60,80,100,200 mesh attached, frequency 290rpm,
The vibration time was 330 seconds, and the sample was 33 g.

As a constituent of the resin of the present invention, a vinyl-based resin such as a vinyl-based polymer using a vinyl-based monomer, a vinyl-based copolymer, and a composition of the polymer and the copolymer is used.

Examples of the vinyl-based monomer (monomer) applicable to the present invention include styrene, styrene such as α-methylstyrene, and p-chlorostyrene and their substitution products; acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate. , Dodecyl acrylate, octyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, monocarboxylic acids having a double bond such as acrylamide, or the like. Substituted products; dicarboxylic acids having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and substituted products thereof; vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate, etc. Kinds; eg vinyl Vinyl ketones such as chill ketone and vinyl excyl ketone; vinyl monomers such as vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and the like are used alone or in combination of two or more. Among them, a combination of a styrene polymer and a styrene copolymer is preferable.

The selection of the type of initiator, the type of solvent and the reaction conditions for producing the resin of the present invention are important factors for obtaining the resin of the present invention. Examples of the initiator include benzoyl peroxide, 1,1-di (t-butylperoxy) -3,3,5-
Trimethylcyclohexane, n-butyl-4,4-di (t
-Butylperoxy) valerate, dicumyl peroxide, α, α'-bis (t-butylperoxydiisopropyl) benzene, t-butylperoxycumene, di-t
-Organic peroxides such as butyl peroxide, azo and diazo compounds such as azobisisobutyronitrile and diazoaminoazobenzene can be used.

As the crosslinkable monomer, a compound having two or more polymerizable double bonds is mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline And divinyl compounds such as divinyl ether, divinyl sulfide and divinyl sulfone, and compounds having three or more vinyl groups are used alone or as a mixture. Among them, divinylbenzene is effective.

Further, the resin of the present invention shows a glass transition point value considerably different depending on the type and composition of the monomer contained as a component, but the glass transition point is 55 ° C. or higher to 80 ° C. for blocking resistance and fixing property. It is preferable in terms. Glass transition temperature is 55 ℃
If it is lower than the above range, thermal coagulation caking during toner storage is very likely to occur, and coagulation troubles easily occur in the copying machine. On the contrary, when the glass transition point exceeds 80 ° C, the heat fixing efficiency also deteriorates.

As a method of synthesizing the binder resin according to the present invention, a method of synthesizing two or more kinds of polymers is basically preferable.

That is, this is a method in which a first polymer soluble in THF and soluble in a polymerizable monomer is dissolved in the polymerizable monomer, and the monomer is polymerized to obtain a resin composition. In this case, a composition is formed in which the former and the latter polymers are uniformly mixed.

The first polymer soluble in THF is preferably solution polymerization or ionic polymerization, and the second polymer for producing a component insoluble in THF is prepared under the conditions in which the first polymer is dissolved. It is preferable to synthesize by suspension polymerization or bulk polymerization in the presence of a crosslinking monomer. The first polymer is 10 parts by weight based on 100 parts by weight of the polymerizable monomer for forming the second polymer.
It is preferred to use ~ 100 parts by weight.

FIG. 1 of the accompanying drawings shows a GPC chart of the THF-soluble component of the resin composition obtained in Synthesis Example 1 described later. Second
The figure shows a GPC chart of polystyrene prepared by solution polymerization, which is the first polymerization in Synthesis Example 1.
The polystyrene was soluble in THF, was soluble in the styrene monomer and n-butyl acrylate monomer, which were the polymerization monomers, and had a main peak at a molecular weight of 3,500. FIG. 3 is a GPC chart of a THF-soluble component of a styrene-n-butyl acrylate copolymer prepared by the second polymerization under the same conditions except that the polystyrene is not added, but produced by suspension polymerization. Is shown. The styrene-n-butyl acrylate copolymer had a main peak at a molecular weight of 37,000.

FIG. 4 is a combination of the chart of FIG. 2 and the chart of FIG.

FIG. 5 shows a combination of the chart of FIG. 1 and the chart of FIG. 4 (the solid line portion is shown by a broken line). As is clear from FIG. 5, the resin composition obtained in Synthesis Example 1 according to the present invention is different from that obtained by simply mixing separately polymerized polystyrene and styrene-n-butyl acrylate copolymer in GPC chart. Had. In particular, it is found that a polymer component that was not generated by the styrene-n-butyl acrylate copolymer alone was formed on the high molecular weight side. This high molecular weight component acts as a polymerization regulator because the polystyrene prepared by the first stage solution polymerization is present during the second stage polymerization, suspension polymerization. As a result, it is considered that the synthesis of the THF-insoluble portion and the THF-soluble portion of the styrene-n-butyl acrylate copolymer was adjusted. In the resin composition according to the present invention, a THF-insoluble component, a THF-soluble high molecular weight component, a THF-soluble intermediate molecular weight component, and a THF-soluble low molecular weight component are uniformly mixed.

Further, in the present invention, the component having a molecular weight of 500,000 or more in GPC of the THF soluble component of the toner is 5 to 5 based on the binder resin.
Those containing 30% by weight (preferably 5 to 25% by weight) are preferable. Further, in the GPC of the THF-soluble component of the toner, those having a clear peak at a molecular weight of 500,000 or more are preferable from the viewpoint of further improving offset resistance and bending resistance.

In such a polymerization method, it is preferable to use a small amount of the aforementioned crosslinking agent. GP in combination with a small amount of cross-linking agent
Without changing practically affecting the peak position in the range of 15,000 to 200,000 in the molecular weight distribution of C,
It is possible to increase the content ratio of 500,000 or more components.

In general, when performing polymerization for such a purpose, generally, a delicate adjustment of the polymerization temperature or an adjustment of the amount of the polymerization initiator is performed. Problems such as a long polymerization reaction time are likely to occur. Further, the peak position is large and easily shifted to the high molecular weight side, and it is difficult to adjust the molecular weight in a specific range. In the present invention, the molecular weight can be adjusted relatively easily by using a small amount of the crosslinking agent together. The preferred addition amount of such a crosslinking agent is 0.1% by weight or less with respect to the polymerizable substance at the time of polymerization,
More preferably, it is 0.07% by weight or less.

The solution polymerization and the suspension polymerization according to the present invention will be described below.

As the solvent used in the solution polymerization, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene and the like are used. In the case of a styrene monomer, xylene, toluene or cumene is preferred. It is appropriately selected depending on the polymer to be polymerized. Further, the initiator is di-tert-butyl peroxide, tert-butyl peroxybenzoate, benzoyl peroxide, 2,
2'-azobisisobutyronitrile, 2,2'-azobis (2,4 dimethylvaleronitrile) or the like is used in a concentration of 0.1 part by weight or more (preferably 0.4 to 15 parts by weight) based on 100 parts by weight of the monomer. Can be As the reaction temperature, the solvent used,
Depends on the initiator and polymer to be polymerized,
It is better to carry out at 0 ° C. In the solution polymerization, it is preferable to carry out the polymerization at 30 parts by weight to 400 parts by weight with respect to 100 parts by weight of the solvent.

In the suspension polymerization, the polymerization is preferably carried out with 100 parts by weight or less (preferably 10 to 90 parts by weight) of the monomer based on 100 parts by weight of the aqueous solvent. As a dispersant that can be used, polyvinyl alcohol, polyvinyl alcohol partially saponified, calcium phosphate and the like are used, and there is an appropriate amount in terms of the amount of a monomer with respect to the aqueous solvent, but generally, with respect to 100 parts by weight of the aqueous solvent.
Used in 0.05 to 1 part by weight. The polymerization temperature is suitably from 50 to 95 ° C, but should be appropriately selected depending on the initiator used and the intended polymer. Also, as the type of initiator,
As long as it is insoluble or hardly soluble in water, it can be used, for example, benzoyl peroxide, tert.
-Butyl peroxyhexanoate is a monomer 100
It is used at 0.5 to 10 parts by weight relative to parts by weight.

In the toner using the resin of the present invention, in addition to the above-mentioned binder resin component, the following compound is contained in a proportion smaller than the content of the binder resin component, as long as the effect of the present invention is not adversely affected. You may.

For example, silicone resin, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin such as low molecular weight polyethylene or low molecular weight polypropylene, aromatic system Examples include petroleum resin, chlorinated paraffin, and paraffin wax.

The magnetic fine particles used in the present invention may be any material exhibiting magnetism or magnetizability, for example, metals such as iron, manganese, nickel, cobalt and chromium, magnetite, hematite, various ferrites, manganese alloys and other ferromagnetic alloys. And the like, and fine powders having an average particle size of about 0.05 to 5 μ (more preferably 0.1 to 1 μ) can be used. The amount of magnetic fine particles contained in the magnetic toner is
15 to 70% by weight of the total toner weight is preferable.

In addition, various substances can be added to the toner according to the present invention for the purpose of controlling coloring and charge. For example, carbon black, iron black, graphite, nigrosine, a metal complex of a monoazo dye, ultramarine blue, phthalocyanine blue, haiza yellow, benzidine yellow, quinacridone, various lake pigments and the like.

The toner prepared from the above-mentioned binder resin, magnetic fine particles, colorant, charge control agent, etc. has a strong resistance to the load received in the developing device and was not crushed and deteriorated in the durability test. .

As a fixing aid, an ethylene-based olefin polymer may be used together with a binder resin.

Here, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyethylene There is an ionomer having a skeleton. In the above copolymer, 50 mol% or more (more preferably 60 mol%
Above) is preferred.

The method for producing a toner using the resin according to the present invention comprises a step of mixing a toner material with a powder, a step of thermally kneading, and a step of pulverizing, and a classification step is added if necessary.

Next, an electrophotographic method using a developer using the resin according to the present invention will be described.

In the step of developing the electric latent image with the toner, the magnetic brush method, the cascade developing method, the powder cloud method, the method using the conductive magnetic toner described in US Pat. No. 3,909,258, JP-A-53-31136 discloses a method of using a high resistance magnetic toner.
The developer using the resin according to the present invention is also suitable for a developing method using a so-called one-component insulating developer containing magnetic fine particles. In the step of transferring the developed image to the transfer-receiving member, an electrostatic transfer method such as a corona transfer method or a bias transfer method is used.

Further, in the toner using the binder resin of the present invention,
A blade cleaning method, a fur brush cleaning method, or the like is applied to the step of removing the residual toner on the photosensitive layer or the insulating layer, and is particularly suitable for the blade cleaning method.

The powder image on the member to be transferred needs to be fixed on the member. As a method for this, a heat fixing method, a solvent fixing method, a flash fixing method, a laminating fixing method, and the like can be used. Suitable for roller fixing system.

[Examples] In the following, "parts" means "parts by weight".

Synthesis Example 1 200 parts of cumene was placed in a reactor and heated to a reflux temperature. A mixture of 100 parts of styrene monomer and 8 parts of di-tert-butyl peroxide was added dropwise thereto over 4 hours under reflux of cumene. Further under cumene reflux (146 ° C to 156 ° C)
To complete solution polymerization, and cumene was removed. The resulting polystyrene is soluble in THF, Mw = 3,700, Mw / Mn = 2.6
4. The molecular weight where the main peak of GPC is located is 3,500, Tg = 57
° C. A GPC chart of the polystyrene is shown in FIG.

Dissolve 30 parts of the polystyrene in the following monomer mixture,
A mixed solution was obtained.

170 parts of water in which 0.2 part of partially saponified polyvinyl alcohol having a degree of polymerization of 2000 was dissolved was added to the above mixed solution to prepare a suspension dispersion liquid. The above suspension dispersion was added to a reactor containing 15 parts of water and replaced with nitrogen, the stirring speed was 200 rpm, and the reaction temperature was 70-
A suspension polymerization reaction was carried out at 95 ° C for 6 hours. After completion of the reaction, the mixture was separated, dehydrated and dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer. The resin powder obtained was spherical particles and aggregates thereof, and the particle size was cumulative 50
The value was 0.1 mm. The resin powder on 20 mesh was 2 wt% of the whole. In this composition, the THF-insoluble component and the THF-soluble component were uniformly mixed, and the polystyrene and the styrene-n-butyl acrylate copolymer were uniformly mixed. THF insoluble matter (24 mesh pass,
(Measured with 60 mesh on powder) was 1 wt% or less. Also, when the molecular weight distribution of the THF-soluble component was measured, it had peaks at the positions of about 40,000 and about 33,000 on the GPC chart, Mn = 0.590, Mw = 150,000, Mw / Mn = 25, molecular weight 1 Less than 10,000 was 28 wt%. Furthermore, the Tg of the resin is 59 ° C, and the GP
The glass transition temperature Tg ₁ of less than 10,000 components collected by C is
56 ° C. W ₂ / W ₁ was about 0.3.

 The GPC chromatogram of the THF-soluble component is shown in FIG.

The properties relating to the molecular weight of each resin and the resin composition were measured by the following methods.

Using Shodex KF-80M as a GPC measurement column, it was installed in a 40 ° C heat chamber of a GPC measurement device (Waters 150C ALC / GPC), a THF flow rate of 1 ml / min, and a detector under RI conditions. Concentration of solute about 0.1% by weight) 200μ
GPC was measured by 1 injection. As a calibration curve for molecular weight measurement, the molecular weight is 0.5 × 10 ³ , 2.35 × 10 ³ , 10.2 × 10 ³ , 35 × 1
0 ³ , 110 × 10 ³ , 200 × 10 ³ , 470 × 10 ³ , 1200 × 10 ³ , 2700 × 10 ³ ,
A THF solution of 10 points of 8420 × 10 ³ monodisperse polystyrene reference substances (manufactured by Waters) was used.

Synthesis Example 2 150 parts of cumene was placed in a reactor and heated to a reflux temperature. The following mixture was added dropwise over 4 hours under cumene reflux.

Further, the polymerization was completed under cumene reflux (146 ° C to 156 ° C) to remove cumene. The obtained styrene-n-butyl acrylate copolymer had Mw = 6,900, Mw / Mn = 2.3, a main peak at a position of molecular weight 7,100, and Tg = 60 ° C.

40 parts of the styrene-n-butyl acrylate copolymer was dissolved in the following monomer mixture to obtain a mixture.

Polyvinyl alcohol partially saponified in the above mixed solution 0.
170 parts of water in which 15 parts were dissolved was added to obtain a suspension dispersion liquid.

The above dispersion liquid was added to a reactor in which 15 parts of water was placed and the atmosphere was replaced with nitrogen. The stirring speed was 200 rpm, and the reaction temperature was 70 to 95 ° C.
The suspension polymerization reaction was carried out for an hour. After completion of the reaction, separate, dehydrate and dry, separate by styrene-n-butyl acrylate, dehydrate and dry, composition of styrene-n-butyl acrylate copolymer and styrene-n-butyl methacrylate copolymer Got The obtained resin powder is spherical particles and aggregates thereof,
The particle size was 0.7 mm at a cumulative 50% value. The resin powder on 20 mesh was 5 wt% of the whole.

Synthesis Example 3 200 parts of cumene was charged into a reactor and heated to a reflux temperature. The following mixture was added dropwise over 4 hours under cumene reflux.

Further, the polymerization was completed under cumene reflux (146 ° C to 156 ° C) to remove cumene. The obtained polystyrene has Mw =
It had a main peak at 4,300, Mw / Mn = 2.64 and a molecular weight of 4,200, and had Tg = 64 ° C. 30 parts by weight of the polystyrene was dissolved in the following monomer mixture to obtain a mixture.

Polyvinyl alcohol partially saponified in the above mixed solution 0.
250 parts of water in which 1 part was dissolved was added to give a suspension dispersion.

The above dispersion liquid was added to a reactor in which 15 parts of water was placed and the atmosphere was replaced with nitrogen. The stirring speed was 200 rpm, and the reaction temperature was 70 to 95 ° C.
Allowed to react for hours. After completion of the reaction, the mixture was separated, dehydrated and dried to obtain a composition of polystyrene and styrene-2-ethylhexyl acrylate copolymer. The obtained resin powder was spherical particles and aggregates thereof, and the particle size was 0.13 mm in cumulative 50% value. Moreover, the resin powder on 20 mesh was 32% of the whole.

Synthesis Example 4 150 parts of cumene was placed in a reactor and heated to a reflux temperature. The following mixture was added dropwise over 4 hours under cumene reflux.

Further, the polymerization was completed under cumene reflux (146 ° C to 156 ° C) to remove cumene. The obtained polystyrene has Mw =
It had a main peak at 5,200, Mw / Mn = 2.74, and a molecular weight of 5,300, and had Tg = 75 ° C. 30 parts by weight of the polystyrene was dissolved in the following monomer mixture to obtain a mixture.

Polyvinyl alcohol partially saponified 0.1 to the above mixture
230 parts of water in which 1 part was dissolved was added to obtain a suspension dispersion liquid. The above dispersion liquid was added to a reactor in which 15 parts of water was charged and the atmosphere was replaced with nitrogen. The stirring speed was 200 rpm, and the reaction was carried out at a reaction temperature of 70 to 95 ° C for 6 hours. After the reaction was completed, the reaction product was separated, dehydrated, and dried to obtain a composition of polystyrene and a styrene-2-butyl acrylate copolymer. The obtained resin powder was spherical particles and aggregates thereof, and the particle size was 0.5 mm in cumulative 50% value. The resin powder on 20 mesh was 4 wt%.

Example 1 The following materials were powder-mixed with 100 parts by weight of the resin powder of Synthesis Example 1.

Magnetic material 60 parts Negative charge control agent 1 part Release agent 2 parts For powder mixing, use a Henschel mixer with a capacity of 10 l.
The phase weight was weighed to 1650 g and mixed for 30 seconds at about 3000 rpm. The obtained powder mixture was apparently uniform, and no aggregates such as magnetic substances and release agents were found.

When this was kneaded with an extruder, the surface of the kneaded product was smooth and homogeneous, and was sufficiently homogeneously mixed.
This was roughly pulverized, finely pulverized and further classified to produce a toner of about 11 μm.

A developer prepared by mixing 100 parts of this toner with 0.4 part of hydrophobic silica was placed in a Canon copier NP-270Z, and the fixing property, bending resistance and image quality were evaluated.

Although 50,000 sheets were durable, a high density and high image was stably maintained. Furthermore, the fixing property was very good, the bending resistance was also good, and there was no filming or fusion to the photoreceptor.

Further, the blocking property was examined by a change in agglomeration when about 10 g of the toner was put in a 100 cc polycup and left at 50 ° C. for one day. The degree of aggregation was measured with a powder tester manufactured by Hosokawa Micron. At room temperature and at 50 ℃ for 1 day
10% by weight and 12% by weight showed almost the same value, and since the difference (ΔG) was 3%, it was confirmed that there was substantially no blocking.

Example 2 The same result as in Example 1 was obtained by carrying out the same procedure as in Example 1 except that the resin composition of Synthesis Example 2 was used.

Example 3 The same result as in Example 1 was obtained by carrying out the same procedure as in Example 1 except that the resin composition of Synthesis Example 3 was used.

Example 4 The procedure of Example 1 was repeated except that the resin composition of Synthesis Example 4 was used, with the result being almost the same as that of Example 1.

Comparative Synthesis Example 1 The amount of the partially saponified polyvinyl alcohol of Synthesis Example 1 was
The amount was adjusted to 0.3 part, stirring was adjusted, and the resin powder was prepared in the same manner as in Synthesis Example 1 to obtain D50% 0.08 mm, 1 wt% resin powder on 20 mesh. The other properties were almost the same as in Synthesis Example 1.

Comparative Synthesis Example 2 The amount of partially saponified polyvinyl alcohol of Synthesis Example 2 was
The content was adjusted to 0.05 part, the stirring was adjusted, and the resin powder was prepared in the same manner as in Synthesis Example 2 to obtain 12% by weight of D50% 0.81 mm, 20 mesh resin powder. The other properties were almost the same as in Synthesis Example 2.

Comparative Example 1 100 parts by weight of the resin powder of Comparative Synthesis Example 1 was compared with Example 1
The materials were powder mixed as in. Other properties such as powder mixability and pulverizability were almost the same as in Example 1. However, in the image evaluation, the stability of the image quality is slightly scratched, and the durability is a little inferior especially between 40,000 and 50,000 sheets.

Production Comparative Example 2 A toner was prepared in the same manner as in Example 1 except that the resin powder of Comparative Example 2 was used.

In the powder mixing, it was confirmed that the magnetic substance selectively adhered to the inner wall of the Henschel mixer, and the release agent was not well dispersed.

In the following heat kneading step of the extruder, the surface of the kneaded product was slightly smoothed, but a feeling that it was considerably compensated in the heat kneading step was obtained.

After that, the same steps as in Example 1 were performed to obtain almost the same toner. The toner performance was almost the same, but in the same long-term durability test, after 40,000 sheets, the image density,
The image quality deteriorated, and although it was practically usable up to 50,000 sheets, it was a problematic level.

[Advantages of the Invention] By using the binder resin for toner according to the present invention,
It is possible to obtain a toner excellent in fixing property and blocking property.

Further, it is possible to obtain a toner having good dispersibility of a coloring agent, a release agent, especially a magnetic material, and further having excellent developability, particularly image quality, durability and bending resistance.

[Brief description of the drawings]

FIG. 1 shows a GPC chart of the THF-soluble content of the resin composition prepared in Synthesis Example 1. FIG. 2 is a GPC chart of polystyrene used in Synthesis Example 1, and FIG. 3 is a THF obtained by suspension polymerization of the styrene-n-butyl acrylate copolymer used in Synthesis Example 1 alone. The GPC chart of a soluble component is shown. FIG. 4 shows the second
FIG. 5 is a combination of the charts of FIG. 3 and FIG.
The figure shows a chart for comparing and explaining FIG. 1 and FIG. FIG. 6 shows a graph relating to the correlation between the content of components having a molecular weight of 10,000 or less and the toner characteristics.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-60-3644 (JP, A) JP-A-58-82258 (JP, A) JP-A-59-45449 (JP, A) JP-A-59- 218459 (JP, A) JP-A-57-97546 (JP, A) JP-A-61-163347 (JP, A) JP-A-62-223765 (JP, A)

Claims (2)

(57) [Claims] 1. A method in which at least one material selected from the group consisting of magnetic fine particles, a colorant, a charge control agent, and a release agent and a binder resin are mixed, and then a heat kneading step and a pulverizing step are performed. A binder resin for toner used in a toner, wherein the binder resin is substantially spherical or an aggregate of spherical particles, and vinyl resin particles having an average particle diameter of 0.1 to 0.7 mm, The content of THF-insoluble matter in the binder resin is less than 10% by weight (based on the binder resin), and in the molecular weight distribution by GPC of the THF-soluble matter in the binder resin, the weight W ₁ of the component having a molecular weight of 10,000 or less. Is 10 to 50% by weight, and the molecular weight is 500,00
The weight W ₂ of the component of 0 or more is 5 to 30% by weight, the ratio of W ₂ / W ₁ is 0.05 to 2.0, and it has a peak in the region of the molecular weight of 10,000 or less, and the glass transition of the component of the molecular weight of 10,000 or less. 55 points
A binder resin for a toner, which has a temperature of ℃ or higher. 2. A magnetic fine particle, a colorant, a charge control agent, and a release resin are mixed with at least one material selected from the group consisting of a group, and a binder resin, followed by a heat kneading step and a pulverizing step. The toner is a vinyl-based resin particle in which the binder resin is substantially spherical or an aggregate of spherical particles, and the average particle diameter of which is 0.1 to 0.7 mm. Is less than 10% by weight (based on the binder resin), and in the molecular weight distribution by GPC of the THF-soluble component of the binder resin, the weight W ₁ of the component having a molecular weight of 10,000 or less is 10 to 50% by weight. , Molecular weight 500,00
The weight W ₂ of the component of 0 or more is 5 to 30% by weight, the ratio of W ₂ / W ₁ is 0.05 to 2.0, and it has a peak in the region of the molecular weight of 10,000 or less, and the glass transition of the component of the molecular weight of 10,000 or less. 55 points
A toner having a temperature of ℃ or above.