JP2681783B2 - Toner for developing electrostatic images - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, and in particular, obtained by a pulverizing manufacturing method. The present invention relates to an electrostatic image developing toner suitable for fixing with a heat roller.

[Prior Art] Conventionally, many electrophotographic methods are known as described in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748. However, generally, using a photoconductive substance, an electric latent image is formed on the photoreceptor by various means, and then the latent image is developed using toner, and if necessary, transferred to a transfer material such as paper. After transferring the toner image, the toner image is fixed by heating, pressure, heating and pressurizing or solvent vapor to obtain a copy, and the toner remaining on the photoreceptor without being transferred is cleaned by various methods. Is repeated.

In recent years, such a copying apparatus has begun to be used not only as a general purpose copying machine for copying original documents but also as a printer as an output of a computer or a personal copy for individuals.

As a result, smaller, lighter, faster, and more reliable devices have been strictly pursued, and machines have become simpler in various respects. As a result, the performance required of the toner has become higher, and if the performance of the toner cannot be improved, a better machine cannot be realized.

For example, various methods and apparatuses have been developed for a process of fixing a toner image on a sheet such as paper, but the most common method at present is a pressure heating method using a heat roller.

In the pressure heating method using a heating roller, fixing is performed by allowing the toner image surface of the sheet to be fixed to pass through the surface of a heat roller having a surface formed of a material having a releasing property with respect to the toner while contacting the surface under pressure. . In this method, since the surface of the heat roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the heat efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. And is very effective in high speed electrophotographic copiers. However, in the above method, since the surface of the heat roller and the toner image are in contact with each other in a molten state under pressure, a part of the toner image is adhered and transferred to the surface of the fixing roller, and this is retransferred to the next sheet to be fixed, which is so-called. An offset phenomenon may occur and the sheet to be fixed may be soiled. Preventing toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

Conventionally, for the purpose of preventing toner from adhering to the surface of the fixing roller, for example, the roller surface is formed of a material having excellent releasability with respect to the toner, such as silicon rubber or a fluorine-based resin. In order to prevent fatigue, the roller surface is coated with a thin film of a liquid having good releasability such as silicone oil. However, this method is extremely effective in preventing toner offset, but has a problem that a fixing device is complicated because a device for supplying an anti-offset liquid is required. .

This is in the opposite direction to miniaturization and weight reduction, and moreover, silicon oil and the like may evaporate due to heat and contaminate the inside of the machine. Therefore, instead of using a silicon oil supply unit, instead of supplying the anti-offset liquid from the toner during heating, a method of adding a release agent such as low molecular weight polyethylene or low molecular weight polypropylene to the toner has been proposed. Have been. If a large amount of such an additive is added in order to obtain a sufficient effect, filming on a photoreceptor or contamination of the surface of a toner carrier such as a carrier or a sleeve will cause deterioration of an image and pose a practical problem. Therefore, a small amount of release agent is added to the toner so as not to deteriorate the image,
It has been practiced to use a device for supplying a small amount of releasing oil or cleaning the offset toner with a winding type device using a member such as a web.

However, in view of recent requirements for miniaturization, weight reduction, and high reliability, it is necessary and necessary to remove even these auxiliary devices, which is preferable. Therefore, it cannot be coped with without further improvement of the performance such as fixing and offset of the toner, and it is difficult to realize it without further improvement of the binder resin of the toner. As a technique for improving a binder resin of a toner, for example, Japanese Patent Publication No. 51-23354 discloses a toner using a crosslinked polymer as a binder resin. The method is effective for improving, for example, the anti-offset property and the anti-corrosion property, but if the degree of cross-linking is increased, the fixing point is increased, and the fixing temperature is sufficiently low and the anti-offset property and anti-corrosion property are good. Further, no toner having sufficient fixing characteristics has been obtained. In general, in order to improve the fixability, the binder resin must have a low molecular weight to lower the softening point, which is inconsistent with the offset resistance improvement treatment, and in order to reduce the softening point Inevitably, the undesired phenomenon that the glass transition point of the resin is lowered and the toner during storage is blocked.

On the other hand, JP-A-56-158340 proposes a toner comprising a low molecular weight polymer and a high molecular weight polymer. However, the fixing temperature is low, the offset resistance is good and the fixing property is sufficient. 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, with respect to a toner blended with a low molecular weight polymer and a crosslinked polymer, for example, JP-A-58-86558 proposes a toner containing a low molecular weight polymer and an infusible high molecular weight polymer as main resin components. I have. According to this method, the fixability 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 infusible high molecular weight polymer Content 40-90
When the amount is as high as wt%, it is difficult to satisfy both the anti-offset property and the fixing property with high performance. In practice, the fixing property and the anti-offset property are not required unless the fixing device has a liquid supply device for the offset prevention. It is extremely difficult to produce a satisfactory toner.

Further, when the amount of the insoluble and infusible high molecular weight polymer increases, the melt viscosity becomes extremely high due to the heat kneading at the time of toner preparation, so that the heat kneading must be performed at a much higher temperature than usual, or the heat kneading must be performed at a high share. As a result, the former has a problem that the toner characteristics are deteriorated due to the thermal decomposition of other additives, and the latter has a problem that the molecules of the binder resin are excessively cut, and the initial anti-offset performance is hardly obtained.

Also, Japanese Patent Application Laid-Open No. Sho 60-166958 discloses a number average molecular weight (Mn).
A toner comprising a resin component obtained by polymerization in the presence of a low molecular weight poly-α-methylstyrene having a molecular weight of 500 to 1,500 has been proposed.

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

In Japanese Patent Application Laid-Open No. 56-16144, a binder resin component having at least one maximum value in each region of a molecular weight of 10 ³ to 8 × 10 ⁴ and a molecular weight of 10 ⁵ to 2 × 10 ^{6 in} the molecular weight distribution by GPC is disclosed. Contained toners have been proposed. in this case,
Although excellent in anti-offset property, fixing property, filming and fusing to a photoreceptor, image quality, etc., further improvement of anti-offset property and fixing property in toner is demanded. In particular, it is difficult for the resin to meet today's strict requirements while maintaining or improving various other performances by further improving the fixing property.

As described above, it is extremely difficult to achieve high performance related to fixing. 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.

In addition, miniaturization requires that each element be placed in a narrow space. As a result, there is less space for air to flow well, and the heat source of the fixing unit and the exposure system is very close to the toner hopper and the cleaner, so that the toner is exposed to a high-temperature atmosphere. Therefore, the toner cannot be put to practical use unless the toner has more excellent blocking resistance.

As described above, the various performances required of the toner are in most cases contradictory to each other, and it is more and more desired and desired to satisfy both of them with high performance, but there is still insufficient performance.

On the other hand, with regard to developability, assuming that the above-mentioned bending resistance and blocking resistance are satisfied, there is no fog even in continuous copying over a long period of time, it is clear, and high image density is maintained, and high image quality that is not affected by environmental changes. A toner that provides an image is desired.

More specifically, the toner is required to stably provide a clear and high-density image free from fog in the continuous and intermittent copying for a long time from the initial stage, and is further required not to be affected by environmental changes. . Conventionally, it is excellent in a series of fixing characteristics such as blocking resistance and bending resistance,
Further, various resins have been proposed and improved for the purpose of a binder resin for toner which is also excellent in additive dispersibility, but when a certain charge control agent is combined with the binder resin when preparing a toner, When the copying is repeated for a long time, the sleeve (developing sleeve) of the developing device of the copying machine is contaminated with the substance derived from the toner, and the image density is reduced compared to the initial stage. This phenomenon becomes a problem especially during continuous copying of images for a long time, and its solution is strongly desired.

Further, such a toner whose image density decreases due to repeated copying over a long period of time is sometimes environmentally dependent, and the triboelectrification ability of the toner itself decreases, especially in a high temperature and high humidity environment, and the image density becomes more remarkable. The phenomenon of decrease occurs and it is desired to solve it early.

[Problems to be Solved by the Invention] An object of the present invention is to provide a toner image which solves the above problems.

 The objects of the present invention are listed below.

An object of the present invention is to provide a toner having good folding resistance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toner suitable for a hot roll fixing method without applying oil.

An object of the present invention is to provide a toner suitable for a cleaning method using a blade.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toner which is fixed at a low temperature and does not cause fusing and filming to a photoreceptor even in a high-speed system or for a long period of use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner which can be fixed at a low temperature and has excellent blocking resistance, and which can be used sufficiently even in a high-temperature atmosphere in a small machine.

An object of the present invention is to provide a toner having excellent durability particularly for continuous copying of images for a long period of time and maintaining a clear and high image density without fog.

An object of the present invention is to provide a toner that is stable and provides a clear and high image density without fog that is hardly affected by environmental changes.

[Means for Solving the Problems] The present invention relates to a method in which a first vinyl-based polymer soluble in THF and soluble in a vinyl-based monomer is dissolved in a vinyl-based monomer to obtain the first vinyl-based polymer. A binder containing at least a binder resin having a vinyl resin obtained by polymerizing a vinyl monomer in which is dissolved and a nitrogen-containing charge control agent, and having a benzoic acid content of 500 ppm or less, wherein the binder Resin has a THF insoluble content of 10% by weight
In the molecular weight distribution by GPC of less than THF (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 weight w ₂ of the component having a molecular weight of 500,000 or more is 5 to 5%. is 30 wt%, the ratio of w ₂ / w ₁ is 0.05-2.
0, having a peak value in the region of molecular weight 10,000 or less,
The present invention relates to a toner for developing an electrostatic image, wherein the glass transition point of a component having a molecular weight of 10,000 or less is 55 ° C. or higher, and the glass transition point of the toner is 55 ° C. or higher.

 The present invention will be described in detail below.

In order to simultaneously achieve the above objects, various binder resins were used, and the structure and performance of the binder resin were studied from various angles. As a result, it has been found that the ratio can be achieved when the ratio of the THF-insoluble component of the binder resin and the molecular weight distribution of the THF-soluble component are specified. TH binder resin
When dissolved with a solvent such as F, the insoluble matter can be separated into soluble matter, and the soluble matter can be measured for molecular weight distribution by GPC.

The molecular weight distribution of the THF-soluble component, the property of whether the fixable temperature is high or low (hereinafter simply referred to as fixability), the bending resistance and the blocking resistance were examined. As a result, GP
It has been found that the components having a molecular weight of about 10,000 or less and those having a molecular weight of about 10,000 or more have different functions in the C molecular weight distribution.
That is, the content ratio w _{1 of the} component having a molecular weight of 10,000 or less based on the whole binder resin does not strongly influence the fixing property or the anti-offset property as is generally said, but is almost related to either in a specific range. Instead, it was found to be strongly related to grindability instead.

From other studies, the binder resin basically has a content ratio w ₂ of 500,000 or more mainly affecting offset resistance, sticking resistance, bending resistance, and TH
The F-soluble component having a molecular weight of 10,000 or less mainly affects the pulverizability, blocking property, fusion property to the photoconductor, filming property, etc., and the THF-soluble component having a molecular weight of more than 10,000 is mainly used. It was found that the fixability was affected. And the ratio of components with a molecular weight of 10,000 or less is 10 to 50 wt%,
It is preferably 10 to 39 wt%. In order to obtain sufficient performance, the molecular weight is 10,000 or less and has a peak in the region of 2,000 or more (preferably 2,000 to 8,000) with a molecular weight of 15,0.
Area peaks or shoulders of 00-200,000 (preferably 20,000-15,000) are required. 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 a molecular weight of 10,000
If the proportion of the following components exceeds 50 wt%, blocking resistance, fusion to the photoreceptor, filming and the like become somewhat problematic. 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
If it is less than 10% by weight, crushability becomes a problem, and 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 content needs to be Mw / Mn ≧ 5, and if Mw / Mn is less than 5, offset resistance and bending resistance tend to be lowered, which becomes 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 properties such as fixability, 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 the binder resin of the toner of 500,000 or more needs to be 5 to 30% by weight. If the content of 500,000 or more is less than 5 wt%, the offset resistance and bending resistance become problems, and if it exceeds 30 wt%, deterioration such as molecular chain breakage due to heat kneading during toner production occurs. Preferably 50
The content of the component of 0,000 or more is preferably 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 20.
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 comparing, Tg ₁ is temperatures above 55 ℃, the fixability Tg _t is a relation of above 55 ° C., bending resistance, fusing to the photosensitive member, filming, and blocking resistance becomes better.

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 using the generally known ASTM D3418-82.
Performed according to the law.

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 as the intersection of the baseline midline and the 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 GPC molecular weight distribution of the THF-soluble component, the molecular weight is 15,000 to 20.
The height of the highest peak in the region of 0,000 is h ₂ , the molecular weight
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. If Mn <2,000, offset properties and bending resistance become problems, and if 9,000 <Mn, crushability and fixing property become problems.

The THF-insoluble component in the present invention indicates the weight ratio of the polymer component (substantially crosslinked polymer) insoluble in the THF solvent in the resin composition in the toner, and indicates the weight ratio of the resin composition containing the crosslinkable component. 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 (No. 86R, manufactured by Toyo Roshi Kaisha), run through a Soxhlet extractor, extract with 100 to 200 ml of THF as a solvent for 6 hours, evaporate the soluble components extracted by the solvent, and then evaporate to 100 ° C. , And weigh the amount of the THF-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 defined as (W ₃ g). The THF-insoluble content is obtained from the following formula.

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

That is, the column was stabilized in a heat chamber at 40 ° C, THF (tetrahydrofuran) as a solvent was flowed through the column 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. 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.
Combination of agel500, 10 ³ , 10 ⁴ , 10 ⁵ and S made by Showa Denko KK
Hodex KF-80M, KF-802,803,804,805 combination, or Toyo Soda TSKgel G1000H, G2000H, G2500H, G3000
Any combination of H, G4000H, G5000H, G6000H, G7000H, GMH is preferred.

The 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 having a molecular weight of 500,000 or more are
Cut out the molecular weight 10,000 or less of the chromatogram by GPC, calculate the weight ratio with the cutout of molecular weight 10,000 or more,
Using the above-mentioned weight% of the THF insoluble matter, the weight% of the total binder resin is calculated. Further, w ₂ / w ₁ is indicated by the weight ratio of each component.

The evaluation of the bendability is as follows: put out the whole black image, rub it back and forth 10 times with a load of about 200 g, and rub the image of the bent part with silbon paper and paper 10 times with a load of about 200 g. Peeling was represented by a reduction rate (%) of the reflection density.

The vinyl-based resin in the toner of the present invention is obtained by polymerizing one or more vinyl-based monomers selected from styrenes, acrylic acids, methacrylic acids and their derivatives. And charging characteristics are preferable. Examples of monomers that can be used include
Examples of styrenes include styrene, α-methylstyrene, vinyltoluene and chlorostyrene. Acrylic acids, methacrylic acids and their derivatives include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, n-tetradecyl acrylate, n acrylate. -Acrylic acid esters such as hexadecyl, lauryl acrylate, cyclohexyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl acrylate, etc. can be mentioned, as well as methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid. Butyl, Amyl Methacrylate, Hexyl Methacrylate, 2-Ethylhexyl Methacrylate, Octyl Methacrylate, Decyl Methacrylate, Dodecyl Methacrylate, Lauryl Methacrylate, Silicate Methacrylate Rohekishiru, phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, glycidyl methacrylate, methacrylic acid esters such as stearyl methacrylate. In addition to the above-mentioned monomers, a small amount of other monomers such as acrylonitrile, 2-vinyl pyridine, 4-vinyl pyridine, vinyl carbazole, vinyl methyl ether, butadiene, isobrene, maleic anhydride, and maleene within a range that can achieve the object of the present invention. Acids, maleic acid monoesters, maleic acid diesters, vinyl acetate and the like may be used.

As the crosslinking agent used in the toner of the present invention, divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 4-butanediol diacrylate, 1,5-
Pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol ^# 200, ^# 4
Examples include 00, ^# 600 diacrylates, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester type diacrylate (MANADA Nippon Kayaku), and the above acrylates replaced by methacrylates.

Pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxy, polyethoxyphenyl) ) Propane, diallyl phthalate, triallyl cyanurate, triallyl assocyanurate, triallyl isocyanurate, triallyl trimellitate, and diaryl chlorendate.

The method for synthesizing the binder resin according to the present invention is basically preferably a method for synthesizing two or more polymers.

That is, a first vinyl polymer that is soluble in THF and a vinyl monomer is dissolved in a vinyl monomer, and the vinyl monomer in which the first vinyl polymer is dissolved is polymerized. And a vinyl-based resin having a first vinyl-based polymer and a second vinyl-based polymer.
In this case, a composition is formed in which the former and 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. 2 of the accompanying drawings shows a GPC chart of a THF-soluble component of the resin composition obtained in Synthesis Example 1 described later. Third
The figure shows a GPC chart of polystyrene prepared by the first polymerization, solution polymerization. The polystyrene is T
It is soluble in HF and soluble in styrene monomer and n-butyl acrylate monomer, which are polymerized monomers, and has a molecular weight of
It had a main peak at 3,500. FIG. 4 is a GPC chart of a THF-soluble portion of a styrene-n-butyl acrylate copolymer prepared by a second polymerization prepared by suspension polymerization under the same conditions except that the polystyrene is not added. Is shown. The styrene-n-butyl acrylate copolymer had a main peak at a molecular weight of 40,000.

FIG. 5 is a combination of the chart of FIG. 3 and the chart of FIG.

FIG. 6 shows a combination of the chart of FIG. 2 and the chart of FIG. 5 (solid lines are indicated by broken lines). As is clear from FIG. 6, the resin composition obtained in Synthesis Example 1 according to the present invention has a GPC chart different from that obtained by simply mixing separately polymerized polystyrene and styrene-n-butyl acrylate copolymer. 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-capable 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, it is preferable that the GPC having a THF-soluble content of the toner contains 5 to 30% by weight (preferably 5 to 25% by weight) of a component having a molecular weight of 500,000 or more based on the binder resin. 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. By using a small amount of crosslinking agent,
In practice, it is possible to increase the content of 500,000 or more components without giving a practically significant effect on the peak positions in the range of 15,000 to 200,000 in the molecular weight distribution of GPC.

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. By using a small amount of the crosslinking agent according to the present invention, the molecular weight can be adjusted relatively easily. The preferable addition amount of such a crosslinking agent is 0.1% by weight or less, more preferably 0.07% by weight or less, based on the polymerizable substance at the time of polymerization.

From the above, the binder resin as described herein, that is, a monomer in the presence of a low molecular weight polymer, a cross-linking agent is polymerized, bending resistance is particularly excellent in blocking resistance, weak from the low molecular weight region. The binder resin that is evenly mixed up to the cross-linked region is very effective from the viewpoint of developing characteristics and fixing characteristics when used as a toner.

This binder resin is very excellent as a binder resin for normal positive toners and negative toners, but a nitrogen-containing charge control agent is used as a charge control agent for toner, and benzoic acid which is a polymerization initiator decomposition residue remains in the resin. Only when the toner is present to some extent, the developing characteristics of the toner, particularly in the case of continuous copying for a long time, may cause a slight decrease in image density.

Specifically, since the resin composition used in the present invention has a low molecular weight region in the crosslinked matrix, it has excellent dispersibility of the nitrogen-containing charge control agent used when forming a toner and lowers image density due to poor dispersion. However, in the continuous copying for a long time with a medium / high speed copying machine, a slight decrease in image density sometimes occurs.

This is because during long-term continuous durability in high-speed copying, a small amount of the nitrogen-containing charge control agent and a part of the resin composition are physically attached or adsorbed on the surface of the developing sleeve of the copying machine to contaminate the sleeve.

As a result of a study, this sleeve contamination is likely to specifically occur due to the presence of the nitrogen-containing charge control agent and benzoic acid in the resin composition. Therefore, the interaction between the nitrogen-containing charge control agent and benzoic acid causes the nitrogen-containing charge control agent. It is presumed that a part of the resin composition containing the charge control agent is physically attached to or adsorbed on the sleeve surface.

Further, such an interaction between the nitrogen-containing charge control agent and benzoic acid is considered to be a kind of salt formation, and the presence of such a state in the toner is not preferable in the environmental characteristics of the toner, and is high at high temperature and high temperature. This causes a decrease in image density or image quality in a humid environment.

The benzoic acid in the resin composition is a decomposition residue of the polymerization initiator, and when the amount of benzoic acid in the resin is 500 ppm or more, the image density is likely to decrease due to sleeve contamination.
It is less likely to occur at 0 ppm or less, more preferably 300 ppm or less, and a benzoic acid amount of 0 ppm is most preferable. The amount of benzoic acid corresponds to the acid value of the resin composition used for the toner, and when the acid value exceeds 0.5, the image density is likely to decrease due to contamination of the sleeve, and when the acid value is 0.5 or less, it is difficult to occur, and thus it is preferable. Is 0.3 or less, and an acid value of 0 is most preferable. The acid value of the resin is described in JP-A-58-1980.
Although Japanese Patent No. 49 and Japanese Patent No. 55-134861 describe acid numbers of 5 to 100, the idea is completely different from the present invention.

Various methods are conceivable as a method for reducing the amount of benzoic acid to 500 ppm or less, but a method of reducing the amount of benzoyl peroxide, which is a polymerization initiator that gives benzoic acid as a decomposition residue, than usual, a conventional suspension polymerization method. A method of swelling the resin composition obtained in 1. again with a solvent and distilling the decomposition residue together with the solvent under reduced pressure as in a solution polymerization method, and further polymerization in which the decomposition residue as an initiator does not remain in the resin as benzoic acid. An initiator, for example, a polymerization initiator generally represented by the following basic structural formula is preferable, and specifically, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2′-
Azobisisobutyrate, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), etc. may be used for suspension polymerization of monomers in the presence of a low molecular weight polymer and a crosslinking agent. preferable.

(In the formula, R _{1 to} R ₆ are alkyl groups such as methyl group, ethyl group, t-butyl group, neopentyl group, cyclohexyl group,
Cyclic alkyl groups such as cyclopentyl, phenyl groups, aryl groups such as naphthyl groups, aralkyl groups such as benzyl and phenylethyl groups, acetyl groups, acyl groups such as benzoyl groups, methoxy groups, ethoxy groups, cyano groups, ester groups Single or plural are selected from among and combined. Further, they may be partially substituted with the above-mentioned substituents. ) Conventionally known peroxide type initiators and azo initiators are used. As the peroxide-based initiator, the polymerization initiator used in the present invention is acetylcyclohexyl sulfonyl peroxide, i-butyl peroxide, cumyl peroxyneodecanoate, di-isopropyl peroxydicarbonate, di-allyl peroxide. Oxydicarbonate,
Di-n-propylperoxydicarbonate, di-myristyl-peroxydicarbonate, cumylperoxyneohexanoate, di (2-ethoxyethyl) peroxydicarbonate, di (methoxyisopropyl) peroxydicarbonate, di (2-Ethylhexyl) peroxydicarbonate, t-hexyl peroxy neodecanoate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, t-butyl peroxy neodecanoate, t-hexyl per Oxyneohexanoate, t-butylperoxyneohexanoate, 2,4-
Dichlorobenzoyl peroxide, t-hexyl peroxypivalate, t-butyl peroxypivalate,
3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, decanoyl peroxide,
Lauroyl peroxide, cumyl peroxide octoate, succinic acid peroxide, acetyl peroxide, t-butylperoxy (2-ethylhexanoate), m-toluoyl peroxide, benzoyl peroxide, t-butylperoxy. i-butyrate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, t-butylperoxymaleic acid, t -Butyl peroxylaurate, t-butyl peroxy-3,5,5-trimethylhexanoate,
Cyclohexanone peroxide, t-butylperoxyallyl carbonate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5'di (benzoylperoxy) hexane, 2,2-bis (t-butylperoxy) Octane, t-butyl peroxyacetate,
2,2-bis (t-butylperoxy) butane, t-butylperoxybenzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, di-t-butyldiperoxyisophthalate, Methyl ethyl ketone peroxide, di-cumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, α,
α'-bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-
Isopropylbenzene hydroperoxide, di-t
-Butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,1,3,3-tetramethylbutyl hydroperoxide, 2 , 5-Dimethylhexane-2,5-
Examples thereof include dihydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide and the like.

Azo initiators include 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), (1-phenylethyl) azodiene. -Phenylmethane, 2,2'-azobisisobutyronitrile, dimethyl 2,2'-azobisisobutyrate, 2,2'-azobis (2methylbutyronitrile),
1,1'-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2'-azobis2,4,4-trimethylpentane) -2
-Phenylazo-2,4-dimethyl 4-methoxyvaleronitrile, 2,2'-azobis (2-methylpropane), 2,2 '
-Azobis (N, N'-dimethyleneisobutylamidine)
Dihydrochloride, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N'-dimethyleneisobutylamidine), 4,4'-azobis (4-cyanopentano) Ic acid), and the like.

The amount of benzoic acid in the present invention can be measured by gas chromatography using diphenyl ether as an internal standard. Specifically, the resin composition 1,2 g and 1,
25 ml of 2-dichloroethane (EDC) was weighed and stirred at room temperature for 3 hours to swell the sample, benzoic acid was extracted into EDC, and 1% EDC of diphenyl ether was used as an internal standard.
About 0.2 g of the solution is precisely weighed and added to this, and further added with acetone 25
Add ml to make a sample solution. The sample solution is injected into a gas chromatograph (GC-9A, manufactured by Shimadzu Corporation) to obtain a chromatogram. On the other hand, in the same manner, instead of the sample solution, a commercially available benzoic acid reagent (manufactured by Wako Pure Chemical Industries, Ltd., 1
The content of benzoic acid in the measurement sample can be determined based on the calibration curve of diphenyl ether-benzoic acid prepared by the measurement. As the measurement conditions, the used column: NPGS filled glass column (3 m / mφ / 2 m), column temperature 190 ° C., injection temperature: 210 ° C., carrier gas (N ₂ ) flow rate: 50 ml / min, are selected (No. 8). (See Figures to 10).

The nitrogen-containing charge control agent in the present invention is selected from conventionally known charge control agents. As the nitrogen-containing charge control agent,
Generally, nigrosine, an azine dye containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), a basic dye (for example, CIBasic Yellow2 (CI41000), CIBasic Yell).
ow 3, CIBasic Red 1 (CI45160), CIBasic Re
d 9 (CI42500), CIBasic Violet 1 (CI4253
5), CIBsaic Violtet 3 (CI42555), CIBasic V
iolet 10 (CI45170), CIBasic Violet 14 (CI42
510), CIBasic Blue 1 (CI42025), CIBasic Bl
ue 3 (CI51005), CIBasic Blue 5 (CI42140),
CIBasic Blue 7 (CI42595), CIBasic Blue 9
(CI52015), CIBasic Blue 24 (CI52030), C.
I.Basic Blue25 (CI52025), CIBasic Blue 26 (C.
I.44025), CIBasic Green Green 1 (CI42040),
CI Basic Green 4 CI42000) and other basic dye lake pigments. , Etc.), CISovent Black 3
(CI26150), Hansa Yellow G (CI11680), CI
Mordlant Black 11, CI Pigment Black 1 etc.

Alternatively, for example, a quaternary ammonium salt such as benzolmethyl-hexadecyl ammonium chloride, decyl-trimethyl ammonium chloride, a polyamine resin such as a vinyl polymer containing an amino group, a condensation polymer containing an amino group, or the like is preferable, and nigrosine is preferable. , Quaternary ammonium salts, triphenylmethane-based nitrogen-containing compounds, polyamines and the like.

The toner of the present invention may be mixed with an additive as required. As the additive, for example, a lubricant such as Teflon, zinc stearate, and polyvinylidene fluoride is preferable, and polyvinylidene fluoride is particularly preferable. Alternatively, abrasives such as cerium oxide, silicon carbide, and strontium titanate, among which strontium titanate is preferable. Alternatively, for example, a fluidity-imparting agent such as colloidal silica and aluminum oxide, particularly hydrophobic colloidal silica is preferable. Anti-caking agent, or carbon black, zinc oxide,
There are conductivity imparting agents such as antimony oxide and tin oxide, fixing aids such as low molecular weight polyethylene, low molecular weight polypropylene, various waxes, etc. or anti-offset agents. Further, a small amount of white fine particles and black fine particles of opposite polarity can be used as a developing property improver.

Further, when the toner of the present invention is used as a two-component developer, it is used by mixing with a carrier powder. In this case, the mixing ratio of the toner and the carrier powder is 0.1 to 50% by weight, preferably 0.5 to 10% by weight, and more preferably 3 to 5% by weight as the toner concentration.

As the carrier that can be used in the present invention, known carriers can be used. For example, magnetic powders such as iron powder, ferrite powder, and nickel powder, glass beads, and the like, and the surfaces thereof are made of fluorine resin or silicon resin And the like surface-treated.

Further, the toner of the present invention can be used as a magnetic toner by further containing a magnetic material. In this case, the magnetic material also serves as a colorant. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxide such as magnetite, hematite, and ferrite or a compound of a divalent metal and iron oxide;
Metals such as iron, cobalt, nickel or these metals and aluminum, cobalt, copper, lead, magnesium,
Examples include alloys of metals such as tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These ferromagnetic materials preferably have an average particle size of about 0.1 to 2 μm, preferably about 0.1 to 0.5 μm, and particularly preferably have a spherical shape. The amount contained in the toner is preferably about 20 to 200 parts by weight, particularly preferably 40 to 180 parts by weight, per 100 parts by weight of the resin component.

Further, a coloring agent may be added to the toner of the present invention as needed.

As the colorant used in the toner of the invention, any suitable pigment or dye is used. Toner colorants are well known and include pigments such as carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengalara, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary and sufficient for maintaining the optical density of the fixed image, and the amount added is 0.1 to 20 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the resin. A dye is further used for the same purpose. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, methine dyes, etc. 0.1 to 100 parts by weight of resin
An addition amount of 20 parts by weight, preferably 0.3 to 3 parts by weight is good.

To prepare the electrostatic image developing toner according to the present invention, the resin composition according to the present invention, a charge control agent, a magnetic material and a pigment or dye as a colorant, if necessary, an additive, etc. are added to a ball mill or the like. After thoroughly mixing with a mixer, the mixture is melted, kneaded and kneaded using a hot kneader such as a heating roll, kneader, extruder or the like to disperse or disperse the pigment or dye while the resins are mutually compatible. After cooling and solidification, the resulting mixture is pulverized and classified to obtain a toner having an average particle size of 3 to 20 μm.

[Examples] In the following formulations, parts are parts by weight.

Synthesis Example 1 200 parts of cumene was placed in a reactor and heated to a reflux temperature. To this, a mixture of 100 parts of styrene monomer and 6 parts of di-tert-butyl peroxide was added dropwise 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 obtained 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. The benzoic acid content of this polystyrene is
It was 0 ppm. The 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.

Partial saponified polyvinyl alcohol compound in the above mixed solution
170 parts of water in which 0.1 part was dissolved was added to give a suspension dispersion. Water 15
The suspension dispersion was added to a reactor which was charged with nitrogen and purged with nitrogen, and a suspension polymerization reaction was performed at a reaction temperature of 70 to 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.
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. The THF insoluble content (measured with a powder of 24 mesh pass, 60 mesh on) of the obtained resin composition was 1 wt% or less. Also, the molecular weight distribution of the THF-soluble component was measured, and it was about 40,000 on the GPC chart.
It has a peak at a position of about 32,000, Mn = 0.58 million, Mw = 140,000, M
w / Mn≈24, and the molecular weight of 10,000 or less was 29% by weight. Further, the Tg of the resin was 59 ° C., and the glass transition point Tg ₁ of 10,000 or less components separated by GPC was 56 ° C. And w ₂ / w ₁
Was about 0.3 and the benzoic acid content was 0 ppm. The acid value was 0.

 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 column for GPC measurement,
Installed in a 40 ° C heat chamber of a measuring device (Waters 150C ALC / GPC) at a THF flow rate of 1 ml / min.
Under the conditions described above, the sample (concentration of THF
GPC was measured by injecting μL. 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.

Comparative Synthesis Example 1 30 parts of the polystyrene obtained in Synthesis Example 1 was dissolved in the following monomer mixture to give a mixed solution.

The mixture was subjected to suspension polymerization in the same manner as in Synthesis Example 1,
A composition of polystyrene and styrene-n-butyl acrylate copolymer was obtained. This resin composition had a THF insoluble content of 70% by weight, and contained a large amount of THF insoluble content. The benzoic acid content of this resin was 1690 ppm.

Comparative Synthesis Example 2 30 parts of the polystyrene obtained in Synthesis Example 1 was dissolved in the following monomer mixture to prepare a mixed solution.

The mixture was subjected to suspension polymerization in the same manner as in Synthesis Example 1,
A composition of polystyrene and styrene-n-butyl acrylate copolymer was obtained. In GPC of the THF-soluble component of this composition, there were peaks at the positions of molecular weights of about 4,000 and 150,000, and the benzoic acid content of this resin was 0 ppm.

Comparative Synthesis Example 3 150 parts of xylene was charged into a reactor, and the temperature was raised to the reflux temperature. A mixture of 100 parts of styrene monomer, 2 parts of tert-butylperoxybenzoate, and 1 part of di-tertbutyl peroxide was added dropwise to the mixture over 4 hours under reflux of xylene. Further, the solution polymerization was completed with xylene (138 to 144 ° C.), and xylene was removed.

The resulting polystyrene is soluble in THF and Mw = 10,000
0, there was a main peak at the position of Mw / Mn = 3.22, molecular weight 11,000, and Tg = 82 ° C. The benzoic acid content of this resin was 620 ppm.

30 parts of the above polystyrene was dissolved in the following monomer mixture to obtain a mixed solution.

The mixture was subjected to suspension polymerization in the same manner as in Synthesis Example 1,
A polystyrene and styrene-n-butyl acrylate copolymer composition was obtained. In the GPC of the THF-soluble component of this composition, there was substantially no peak at a molecular weight of about 10,000 or less. The benzoic acid content of this resin was 1840 ppm.

Comparative Synthesis Example 4 To a monomer mixture described below, 170 parts of water in which 0.1 part of a partially saponified polyvinyl alcohol was dissolved was added to prepare a suspension dispersion.

The above dispersion was added to a reactor which was charged with 15 parts of water and purged with nitrogen, and subjected to a suspension polymerization reaction at a reaction temperature of 70 to 95 ° C for 6 hours. After the reaction was completed, dehydration and drying were performed separately to obtain a styrene-n-butyl acrylate copolymer.

This copolymer had a main peak at a molecular weight of about 17,000, and had substantially no peak at a molecular weight of 10,000 or less. The benzoic acid content of this resin was 3870 ppm.

Comparative Synthesis Example 5 170 parts of water in which 0.1 part of a partially saponified polyvinyl alcohol was dissolved was added to the following monomer mixture to obtain a suspension dispersion liquid.

The suspension dispersion was added to a reactor containing 15 parts of water and purged with nitrogen, and a suspension polymerization reaction was carried out at a reaction temperature of 70 to 95 ° C for 6 hours. After completion of the reaction, the mixture was filtered, dehydrated and dried to obtain a composition of polystyrene and a styrene-n-butyl acrylate copolymer.

The main peak of this copolymer was located at a molecular weight of about 16,000, and there was virtually no peak at a molecular weight of 10,000 or less. The benzoic acid content of this resin was 0 ppm, and the acid value was 0.

Synthesis Example 2 200 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 (146-156 ° C),
Cumene was removed. The resulting polystyrene had Mw = 4,30
0, Mw / Mn = 2.64, having a main peak at a molecular weight of 4,200, T
g = 64 ° C. Benzoic acid content of the obtained resin is 0ppm
Met. 30 parts of the above polystyrene was dissolved in the following monomer mixture to give a mixture.

Polyvinyl alcohol partially saponified 0.1 to the above mixture
170 parts of water in which the above parts were dissolved was added to obtain a suspension dispersion.

The above dispersion was added to a reactor which was filled with 15 parts of water and purged with nitrogen, and reacted at a reaction temperature of 70 to 95 ° C. for 6 hours. After the completion of the reaction, the reaction product was separated, dehydrated and dried to obtain a composition of polystyrene and a styrene-2-ethylhexyl acrylate copolymer.
The benzoic acid content of this resin composition was 0 ppm.

Synthesis Example 3 150 parts of cumene was placed in a reactor and heated to the reflux temperature. The following mixture was added dropwise over 4 hours under cumene reflux.

Further, the polymerization was completed under cumene reflux (146-156 ° C),
Cumene was removed. The resulting polystyrene had Mw = 5,20
0, Mw / Mn = 2.74, main peak at molecular weight 5,300, T
g = 75 ° C. The benzoic acid content was 0 ppm. 30 parts of the above polystyrene was dissolved in the following monomer mixture to give a mixture.

Polyvinyl alcohol partially saponified 0.1 to the above mixture
170 parts of water in which the above parts were dissolved was added to obtain a suspension dispersion. The above dispersion was added to a reactor which was filled with 15 parts of water and purged with nitrogen, and reacted at a reaction temperature of 70 to 95 ° C. for 6 hours. After the reaction is completed,
Dehydrated and dried, polystyrene and styrene-acrylic acid n
-A butyl copolymer composition was obtained. The benzoic acid content of this resin composition was 0 ppm.

Synthesis Example 4 200 parts of cumene was placed in the reactor and heated to the reflux temperature. The following mixture was added dropwise over 4 hours under cumene reflux.

Further, the polymerization was completed under cumene reflux (146-156 ° C),
Cumene was removed. The obtained styrene-α-methylstyrene had a main peak at the position of Mw = 4,500, Mw / Mn = 2.8, molecular weight 4,400, and had Tg = 63 ° C. The benzoic acid content of this resin was 0 ppm.

30 parts of the styrene-α-methylstyrene copolymer was dissolved in the following monomer mixture to obtain a mixture.

Polyvinyl alcohol partially saponified 0.1 to the above mixture
170 parts of water in which the above parts were dissolved was added to obtain a suspension dispersion. The above dispersion was added to a reactor which was filled with 15 parts of water and purged with nitrogen, and reacted at a reaction temperature of 70 to 95 ° C. for 6 hours. After the reaction is completed,
After dehydration and drying, a composition of a styrene-α-methylstyrene copolymer and a styrene-n-butyl acrylate copolymer was obtained. The benzoic acid content of this resin composition was 0 ppm.

Example 1 After pre-mixing the above ingredients with a Henschel mixer,
The mixture was kneaded with a two-roll mill heated to 15 ° C. for 15 minutes. After allowing the kneaded material to cool, coarsely pulverized with a cutter mill, pulverized using a fine pulverizer using a jet stream, and further classified using an air classifier, a black fine powder having a volume average particle size of 11.5 μm was obtained. Obtained. FIG. 1 shows a GPC chart of the THF-soluble component of the black fine powder.

Colloidal silica fine powder for 100 parts of the black fine powder
0.4 part was dry-mixed to obtain a developer (toner).

The blocking property was examined by a change after aggregation when about 10 g of the toner was put in a 100 cc polycup and left at 50 ° C. for 1 day. The degree of aggregation was measured with a powder tester manufactured by Hosokawa Micron. At room temperature and at 50 ℃ for 1 day
The values were almost the same at 10% by weight and 12% by weight, and since the difference (ΔG) was 2%, it was confirmed that there was substantially no blocking.

Canon's copy machine NP for bending resistance and developability
It evaluated using -5540. As for folding resistance, copy the entire black image as described above, fold it so that the image surfaces overlap, rub it 10 times with a load of about 200 g, and rub it again and again with sillbon paper 10 times with a load of about 200 g, then image The peeling off was represented by the reduction rate (%) of the reflection density. According to it, the rate of decline is 6
%, And with regard to developability, when an endurance test of about 50,000 sheets was performed using an image with an image area ratio of about 5%, an image density of 1.25 to 1.35, a clear high-resolution image with no fog was obtained. It was obtained, and neither fusion with the photosensitive member nor filming occurred. In addition, the image density evaluation due to sleeve contamination includes both the image density at the start of copying, the image density after 10,000 continuous copies (ΔD 10,000 sheets), and the image density difference after continuous 50,000 copies (ΔD 50,000 sheets). It was judged by comparing.

According to it, ΔD 10,000 sheets = ± 0.05, ΔD 50,000 sheets = ± 0.08, and the degree of sleeve contamination was good. In continuous copying under the environment of 30 ° C and relative humidity of 90%, a stable image density of 1.25 was obtained, a clear image without fog was obtained, and the high humidity resistance was not a problem.

Comparative Examples 1 to 4 Toners were prepared in the same manner as in Example 1 using the resin compositions prepared in Comparative Synthesis Examples 1 to 4 instead of the resin composition of Example 1, and the toners were prepared in Comparative Examples 1 to 4 And

Evaluation of the toner of the comparative example was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 5 Resin composition prepared in Comparative Synthesis Example 5 with 30 parts of polystyrene (Mw = 3,700, Mw / Mn = 2.64, Tg = 57 ° C.) used in Synthesis Example 1 instead of the resin composition of Example 1 A toner was prepared in the same manner as in Example 1, and the toner was used as Comparative Example 5.

The toner of Comparative Example 5 was evaluated in the same manner as in Example 1 and Table 1
It was shown to.

 The characteristics of the toner are shown in Table 2.

Example 2 A toner was prepared from the above mixture in the same manner as in Example 1. The volume average particle size was 12.0 μm. As the colloidal silica fine powder, one treated with amino-modified silicone oil was used.

 The blocking resistance was ΔG = 2%, and there was no problem.

In addition, the bending resistance is excellent with a concentration reduction rate of 5%,
In terms of developability, we carried out a durability test on 50,000 sheets using an NP-5540 copier.However, from the initial stage, clear images with high resolution without fog with image density of 1.2 to 1.3 were obtained, Neither wearing nor filming occurred. Regarding sleeve contamination, ΔD 10,000 sheets = ± 0.02, ΔD 50,000 sheets = ±
It was 0.04 and there was no problem at all. Also 30 ℃, relative humidity
When continuously copied in an environment of 90%, the image density was stable at 1.25 to 1.35, a clear image free of fog was obtained, and excellent in high humidity resistance.

Example 3 A toner was prepared in the same manner except that the resin composition of Example 2 was changed to the resin composition of Synthesis Example 3 and 3 parts of quaternary ammonium salt was used instead of nigrosine.

 The volume average particle size of the toner was 11.8 μm.

The blocking resistance was ΔG = 2%, and there was no problem.

In terms of bending resistance, the density reduction rate was excellent at 3%. Regarding the developability, a durability test of 50,000 sheets was conducted using an NP-5540 copier. From the initial stage, the image density was 1.3 and high resolution without fog was observed. An image was obtained, and neither fusion with the photosensitive member nor filming occurred. Further, regarding sleeve contamination, ΔD 10,000 sheets = ± 0.04 and ΔD 50,000 sheets = ± 0.04, which were excellent.

Also, in continuous copying under the environment of 30 ° C and relative humidity of 90%,
The image density was stable at 1.25, a clear image with no fog was obtained, and it was excellent in high humidity resistance.

Example 4 A toner was prepared in the same manner as in Example 2, except that the resin composition of Example 2 was changed to the resin composition of Synthesis Example 4. The volume average particle size of the toner was 12.0 μm.

The blocking resistance was ΔG = 3%, and there was no problem.

The bending resistance was as good as the density reduction rate of 6%, and the developability was evaluated by conducting a continuous durability test on 50,000 sheets with a digital copying machine NP-9030 using a Canon amorphous Si photoconductor. As a result, the image density was 1.
A stable image of 3 was obtained, and a clear image without fog was obtained, and there was no fusing or filming on the photoreceptor. With respect to sleeve contamination, ΔD 10,000 sheets = ± 0.03 and ΔD 50,000 sheets = ± 0.04 were excellent, and the high humidity resistance was also excellent as in the above-mentioned examples.

 The characteristics of the toner are shown in Table 2.

[Effects of the Invention] As is clear from the above, the toner of the present invention has excellent bending resistance.

Further, the toner of the present invention is fixed at a low temperature, and the fusion and filming to the photoreceptor do not occur even in a high-speed system or for a long period of use.

Further, it is fixed at a low temperature and has excellent blocking resistance, and it can be sufficiently used even in a high temperature atmosphere in a small machine.

Further, the toner of the present invention has excellent durability against continuous copying of images for a long period of time, and gives a clear and high image density without fog, which is hardly affected by environmental changes.

[Brief description of the drawings]

FIG. 1 shows GPC of the THF-soluble portion of the toner prepared in Example 1.
3 shows a chart. FIG. 2 is a GPC chart of a THF-soluble component of the resin composition prepared in Synthesis Example 1. FIG. 3 shows a GPC chart of the polystyrene used in Synthesis Example 1, and FIG. 4 shows a THC of the styrene-n-butyl acrylate copolymer used in Synthesis Example 1 obtained by suspension polymerization alone.
The GPC chart of the F-soluble component is shown. FIG. 5 shows FIGS. 3 and 4
FIG. 6 shows a chart for comparing and explaining FIG. 2 and FIG. FIG. 7 is a graph showing the correlation between the content of components having a molecular weight of 10,000 or less and the toner characteristics. FIG. 8 is a diagram showing a gas chromatogram of benzoic acid, FIG. 9 is a graph showing a calibration curve of benzoic acid and diphenyl ether, and FIG. 10 is a graph showing a benzoic acid content and an image density reduction amount. It is a graph which shows the relationship of.

 ─────────────────────────────────────────────────── ─── 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 57-97546 (JP, A) JP 61-163347 (JP, A) JP 62-223765 (JP, A) JP 57-211157 (JP, A)

Claims (2)

(57) [Claims] 1. A vinyl monomer in which a first vinyl polymer which is soluble in THF and soluble in a vinyl monomer is dissolved in a vinyl monomer, and the first vinyl polymer is dissolved. A toner containing at least a binder resin having a vinyl resin and a nitrogen-containing charge control agent obtained by polymerizing, and having a benzoic acid content of 500 ppm or less, wherein the binder resin contains a THF insoluble component. The amount is less than 10% by weight (based on the binder resin), and the weight of the component with a molecular weight of 10,000 or less in the GPC molecular weight distribution of the THF soluble component.
w ₁ is 10 to 50% by weight, the weight W ₂ of the component having a molecular weight of 500,000 or more is 5 to 30% by weight, and the ratio of w ₂ / W ₁ is 0.05 to 2.0.
And has a peak value in the molecular weight range of 10,000 or less, the glass transition point of the component having a molecular weight of 10,000 or less is 55 ℃ or more, the glass transition point of the toner is 55 ℃ or more electrostatic charge Toner for image development. 2. The first vinyl polymer is synthesized by solution polymerization or ionic polymerization, and the polymerization of the vinyl monomer in which the first vinyl polymer is dissolved is crosslinkable. The toner for developing an electrostatic charge image according to claim 1, which is suspension polymerization or bulk polymerization in the presence of a monomer.