JPH1124312A - Toner for developing electrostatic charge image and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly disperse colorant in resin in a small particle size state and to obtain excellent image quality by using binder resin having specified particle size. SOLUTION: The binder resin whose volume average particle size is 5 to 20 μm is used as the binder resin of toner where the colorant is dispersed in the binder resin. By setting the particle size of the binder resin in a premixing stage to 5 to 20 μm, the image quality is improved. This is because the specific surface area of the binder resin is large by setting the particle size of the binder resin in premixing to 5 to 20 μm, the quantity of stuck colorant per particle is increased, and the flocculation of the colorant is restrained and the dispersion in powder mixture is uniformized, so that the dispersed state of pigment in melting and kneading is excellent. When the particle size of the binder resin is smaller than 5 μm, the rise of powder surface in the mixing stage, faulty supply to a melting and kneading stage and the flocculation of the binder resin itself are caused, which are undesirable. When it is larger than 20 μm, the dispersion is not uniformized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, and a method for manufacturing the same. The present invention relates to a toner for developing an electrostatic image (including a magnetic one-component toner for developing an electrostatic image) suitable for a copying machine having a toner and a method for producing the same.

[0002]

2. Description of the Related Art A developing toner used in a copying apparatus having a fixing mechanism of a heating roller contacts a surface of the heating roller under pressure while the toner image is in a dissolved state, so that a part of the toner image is formed on the surface of the roller. To cause a paper offset phenomenon. As means for avoiding the offset phenomenon, a toner using a crosslinked polymer as a binder resin (Japanese Patent Publication No. 51-23354) or a toner containing a low molecular weight polyolefin such as polypropylene or polyethylene (Japanese Patent Application Publication No. JP-A-49-6523) and the like have been proposed. These methods are effective in improving the offset resistance and the abrasion resistance, but have not been satisfactory at the same time with respect to the fixing property.

As a binder resin, there has been proposed a polyester resin having excellent low-temperature fixability and offset resistance at high temperatures, and a novolak-type phenol resin as a constituent unit thereof. According to this, anti-offset,
Although the effect should be recognized at both the low temperature fixing and the temperature range required to satisfy them, the results satisfying both are not obtained because the temperature range required to satisfy them is not sufficient. Further, in the olefin-containing toner, the olefin is relatively soft, so that the olefin is liberated by a small force, and the olefin is attached to the surface of the carrier particles and contaminated. This contamination greatly impairs the triboelectric charging property between the toner and the carrier. As a result, charging instability occurs at an early stage, and fogging is observed in an image. Further, since the toner containing olefin has low fluidity, the supply amount of the toner to the developing unit becomes unstable, and image unevenness is likely to occur.

[0004] Conventionally, in the heating roller fixing method,
To prevent the toner from adhering to the surface of the fixing roller, for example, the surface of the fixing roller is formed of a material having excellent releasability with respect to the toner such as a fluororesin, and an anti-offset liquid such as silicone oil is further supplied to the surface. Then, the roller surface is coated with a thin film of liquid. Although this method is extremely effective in preventing offset of the toner, it generates an odor when the offset preventing liquid is heated, and requires an apparatus for supplying the offset preventing liquid. The mechanism of the copying apparatus becomes complicated, and high accuracy is required to obtain a stable image, so that the copying apparatus is expensive.

In addition, when the toner for developing an electrostatic charge image is a magnetic toner, if the magnetic toner image is fixed by a heat roller fixing method, which is preferable as a fixing method, a magnetic toner which does not thermally melt in the magnetic toner can be obtained. Because of the presence of body particles, there is a problem that poor fixing is likely to occur particularly under low-temperature and low-humidity environmental conditions. In addition, since the magnetic particles contained in the magnetic toner are hard and the magnetic particles are present in a state where they are also exposed on the surface of the magnetic toner particles, the magnetic toner is developed using such a magnetic toner by a magnetic brush developing method. Is performed, scratches are easily generated on the surface of the latent image carrier by the magnetic brush, and the scratches are particularly noticeable under low-temperature and low-humidity environmental conditions. Further, when the image formation is repeated a number of times, the abrasion increases, and as a result, when using a latent image carrier having an organic photosensitive layer in which the abrasion easily occurs, the cleaning failure becomes remarkable, and the abrasion portion And the image roughness becomes remarkable.

It is more difficult to obtain a toner free of the offset phenomenon when considering application to a high-speed copying machine using a heat roller without using much electric power for a fixing device, that is, a so-called labor-saving high-speed copying machine. Meet the problem. That is, in order for the offset phenomenon not to occur, the binder polymer used in the toner is required to be as tough as possible and have sufficient melt fluidity. However, in order to have melt fluidity, the toner must be heated to a considerably high temperature, which does not satisfy the demand for labor saving. Therefore, in order to save labor, fixing at a low temperature is required, and it is preferable to use a resin having a low glass transition point and a low molecular weight. However, a resin having a low molecular weight naturally has no toughness and easily causes an offset phenomenon.

Hitherto, toughening of the toner for preventing offset has generally used a high-molecular polymer having an average molecular weight of about 100,000 or more, especially a vinyl polymer in many cases. In order to fix a toner using a high molecular weight vinyl polymer at a low temperature, there are methods such as lowering the glass transition point of the polymer as low as possible without blocking, or lowering the fixing temperature by adding a plasticizer. However, these methods not only lower the fixing point (the lowest temperature at which complete fixing is performed), but also lower the hot offset temperature (the temperature at which offset starts to occur). , The so-called fusing latitude is merely moved to the lower temperature side. Also, if an attempt is made to prevent a decrease in the hot offset temperature due to an increase in the weight average molecular weight, the viscosity of the resin increases,
The effects of lowering the glass transition point and adding a plasticizer are diminished, and furthermore, the pulverizability is deteriorated due to the large amount of crosslinked components.

On the other hand, a polyester resin has a low glass transition point, unlike a vinyl polymer, and can easily obtain a resin having a low molecular weight. This means that a low-temperature fixing toner can be easily obtained. However,
Since the polyester resin is a low molecular weight resin, the degree of offset is high and the polyester resin cannot be used as it is for a heat roller toner.

In order to take advantage of the advantages of both the property that the vinyl polymer does not cause an offset up to a high temperature and that the polyester can be fixed even at a low temperature, it is conceivable to blend both resins. No. 54-114245. However, a high-molecular-weight vinyl polymer and a low-molecular-weight polyester resin are poorly compatible with each other, resulting in a non-uniform dispersion state. In particular, as the molecular weights of the two differ, the compatibility deteriorates, and when the dispersion state is observed with a phase contrast microscope or the like, the dispersion state is observed as if there are islands in the sea. This is also observed when blending poorly compatible plastics. As a sea-island theory, Plastics, 13, No. 9, 1 (1
962).

When the above-described sea-island is formed in the toner resin, the other components of the toner, such as a polarity controlling agent such as a dye and a colorant such as carbon black and a magnetic material, become insufficiently dispersed. In the repeated copying, oppositely charged toner and the like are generated, and so-called fogging occurs. On the other hand, in order to improve the dispersibility of the polyester resin and the vinyl polymer, a method has been proposed in which a common segment is introduced into both to form a graft copolymer. However, such a resin is averaged without taking advantage of each other's advantages of hot offset resistance and low-temperature fixability.

In addition to image transfer quality, image quality is also an important quality item for electrostatic charge image developing toner. Image quality, especially the cause of fogging, improvement for weakly charged components,
Various charge control agents have been developed to reduce the reverse charge component, and techniques for adding various substances to the toner surface and control of the surface shape have been attempted in order to improve the fluidity and charge rise. Further, various melt-kneading techniques have been proposed to efficiently and uniformly disperse the charge control agent and the colorant with a small particle diameter in the binder resin. Improvements in image quality and fogging have been studied by the above-mentioned attempts, but have not yet been solved.

[0012]

SUMMARY OF THE INVENTION A first object of the present invention is to improve image quality, especially fog, by developing a micropigment-dispersed toner. A second object of the present invention is to provide a toner for developing an electrostatic image, which is suitable for a heat roller fixing method, can perform low-temperature fixing, and has excellent hot offset properties, and a method for producing the same. A third object of the present invention is to provide a toner for developing an electrostatic image having good stability in charging environment and a method for producing the same. A fourth object of the present invention is to provide a toner for developing an electrostatic image capable of providing a binder resin having a small power load at the time of kneading a toner in a pulverized toner production line and exhibiting high productivity (pulverizability of a material). It is in providing the manufacturing method.

[0013]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that in a toner for developing an electrostatic charge image in which a colorant or the like is dispersed in a binder resin, the volume average particle size of the binder resin when mixing the raw material powders is increased. The dispersion of the colorant is improved by reducing the diameter to a smaller diameter, and furthermore, the physical properties of the binder resin,
The inventors have found that the toner obtained by specifying the physical properties of the colorant and the toner manufacturing process is suitable for the above purpose, and have completed the present invention. According to the present invention, (1) in an electrophotographic toner in which a colorant is dispersed in at least a binder resin, the binder resin has a volume average particle diameter of 5 to 5.
(2) The toner according to (1), wherein the binder resin is a polycarboxylic acid component (A) and a polyol component (B).
And at least a part of the polyol component (B) is an oxyalkylene ether (B1) of a novolak-type phenol resin, and is contained in the toner in the following conditions (a) and (b): A toner for developing an electrostatic charge image characterized by being present; (a) not containing a tetrahydrofuran-insoluble component; and (ii) containing 5 to 20% by weight of a component having a molecular weight of 1 × 10 ⁷ or more. Provided.

According to the present invention, (3) the above (1)
Or the toner for developing an electrostatic image according to (2), wherein the binder resin is formed by blending a vinyl resin with a polyester resin having a polycarboxylic acid component (A) and a polyol component (B) as constituent units. . (4) In the above (1), (2) or (3), the binder resin has a molecular weight distribution of 2,000 as determined by gel permeation chromatography (GPC) of the tetrahydrofuran dissolved portion.
A toner for developing an electrostatic image, having a main peak in a region of from 1 to 10,000 and having a molecular weight of 10,000 or less in an amount of 50 to 70% by weight. (5) In the above (1), the colorant is carbon black. Having a specific surface area measured by BET of 100 to 150 m ² / g and a pH of 7
Less than, a toner for developing an electrostatic image,
(6) In the above (1), (2), (3), (4) or (5), a step of powder-mixing the binder resin with a coloring agent, a charge controlling agent, a wax and other raw materials. (7) The method for producing a toner for developing an electrostatic image, wherein the weight ratio of the mixture with the colorant is colorant: binder resin = 1: 1 to 1:20. (3) In (4), (5) or (6), a mixture of a binder resin and a colorant is used as a masterbatch for highly dispersing the colorant.
A method for producing a toner for developing an electrostatic image, characterized by mixing powder with a binder resin having a particle size of 0 μm or more and other materials.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. According to the study of the present inventors, several kinds of raw materials are measured, mixed with material powder, melt-kneaded, finely pulverized, classified, and a colorant or the like is dispersed in a binder resin manufactured through a process of mixing additives. In the toner for developing an electrostatic image, by defining the particle size, physical properties, physical properties of the colorant, and the mixing ratio production process of the binder resin in the raw material powder mixing process, a micro-pigment-dispersed toner can be obtained. It was found that quality improvement, low-temperature fixing, and high productivity could be achieved.

In general, when producing a toner, a uniaxial or biaxial continuous kneader, two or three, is used to uniformly and finely disperse several kinds of substances such as a colorant, a wax, a charge controlling agent, and a magnetic powder in a binder resin. The mixture is melt-kneaded at 100 to 200 ° C. by a batch-type kneader such as a roll. However, in order to uniformly and finely disperse the material, the particle diameter of the binder resin in the material powder mixing step, that is, the so-called pre-mixing step, which is a step prior to the melt-kneading, is important. The binder resin usually used for toner is synthesized by a method such as solution polymerization, emulsion polymerization or suspension polymerization, and is finally coarsely pulverized by a mechanical pulverizer such as a hammer mill and the particle size is adjusted by a predetermined mesh. You. The mesh opening is generally 1 to 4 mm. On the other hand, the particle size of other raw materials mixed in the pre-mixing step, particularly the colorant (carbon) and the charge control agent, is extremely small (in the case of carbon, the primary particle size measured by a microscopic method is 0.01 to 0.1. 03 μm, 0.1 to 0.
Aggregates are easily formed due to the large specific surface area, and are not sufficiently dispersed in the binder resin during pre-mixing because of insufficient dispersion in the pre-mixing, and adversely affect image quality, especially fogging and charging rise. Was exerted.

This time, it was found that the image quality was improved by setting the particle size of the binder resin in the pre-mixing step to 5 to 20 μm. The mechanism of improvement is
By setting the particle size of the binder resin in the pre-mixing to 5 to 20 μm, the specific surface area of the binder resin is increased, the amount of the attached colorant per particle is increased, the aggregation of the colorant is suppressed, and the dispersion in the powder mixing is performed. This is because, as a result of achieving uniformity, the dispersion state of the pigment was improved in the melt-kneading. As a method for reducing the particle size of the binder resin, a jet-type air-mill mechanical pulverizer or the like, which is a general pulverizer, is used. If the particle size of the binder resin is smaller than 5 μm, the powder surface rises in the pre-mixing step, poor supply to the subsequent melt-kneading step, and the binder resin itself forms aggregates, which is undesirable. If it is larger than 20 μm, the rate of increase in the specific surface area is small, so that it is difficult to achieve uniform dispersion.

The toner of the present invention has a particle size of 5 to 20 μm.
The mixing ratio (weight ratio) of the small particle size binder resin and the colorant is as follows: colorant: small particle size binder resin = 1: 1 to 1: 2
It is preferably 0. If the ratio of the binder resin having a small particle diameter is larger than 20, the degree of coloring required for the toner cannot be obtained, and a problem such as a decrease in image density occurs. On the other hand, if it is smaller than 1, the amount of the colorant with respect to the binder resin is too large, and the colorant forms an aggregate, so that uniform dispersion cannot be achieved by pre-mixing. Further, a mixture of the above-mentioned binder resin having a small particle diameter and a colorant can be used as a masterbatch for highly dispersing the colorant.
In other words, in the pre-mixing step of powder-mixing the binder resin and several other types of raw materials, agglomeration between the other raw materials and the colorant is prevented by powder-mixing the binder resin and the colorant with a small particle diameter in advance, and the resin and The coloring agent can be sufficiently dispersed. A mixed powder in which a binder resin having a small particle size and a colorant are sufficiently dispersed in advance is further added with a particle size of 2
By additionally mixing a binder resin resin and other raw materials of 0 μm or more, further powder uniformity in pre-mixing can be ensured.

The binder resin in the toner of the present invention comprises:
It is a polyester resin having a polycarboxylic acid component (A) and a polyol component (B) as constituent units, or a polyester resin blended with a vinyl resin. At least a part of the polyol component (B) is (a) Substantially free of tetrahydrofuran-insoluble components, and (b)
It is an oxyalkylene ether (B1) of a novolak type phenol resin containing 5 to 20% by weight of a component having a molecular weight of 1 × 10 ⁷ or more. Here, the states (a) and (b) can be obtained by molecular shearing due to kneading mechanical energy in toner production. The above (b)
The reason why the molecular weight is 1 × 10 ⁷ or more is that a molecular weight of 10 ⁷ or more cannot be measured at present.

Further, the toner of the present invention has a main peak in a region where the weight average molecular weight is 2,000 to 10,000 in the molecular weight distribution by GPC of the THF solution of the binder resin, and contains 50 to 70% by weight of a molecular weight of 10,000 or less. By doing so, the pulverizability and low-temperature fixability are improved.
If the THF-insoluble content or the component having a molecular weight of 1 × 10 ⁷ or more exceeds 20% by weight, a decrease in fixability and a decrease in dispersibility of pigment and wax occur.

Further, the use of a novolak type phenol resin is effective for reducing the environmental stability characteristic of the polyester resin, which is hardly affected by moisture in the air. In this case, the Tg of the binder resin is reduced by 50%. ~ 65 ° C
To reduce the acid value and hydroxyl group as much as possible, so that the acid value is 1 to 5 m
gKOH / g, hydroxyl value is 30 to 80 mgKOH / g,
Within this range, the low-temperature fixability is further improved, and the charging stability in a high-temperature environment is improved.

In addition, when the vinyl resin is blended in an amount of 30% or less of the resin system, the environmental friendliness of the vinyl resin is enhanced by the polyester resin containing the polycarboxylic acid component (A) and the polyol component (B) as constituent units. It is even better than using it alone. At this time, the water content of the binder resin is (3
When the temperature is adjusted to 5,000 ppm or less (preferably 3,000 or less) at 0 ° C., 60% for 24 hours, the charging stability in a high-temperature environment is further improved.

In addition to the above, it is advantageous to add a wax having an effect on the releasability as a means for further improving the hot offset property. However, as wax increases, it causes problems such as spent with a carrier and reduced charge due to reduced dispersibility with a charge controlling agent. Therefore, it is desirable to prevent spent by setting the dispersed particle size of the wax to 2 μm or less. In order to improve the cleaning property, it is desirable that the toner contains a magnetic material having a particle diameter of 0.1 μm or less. The amount of magnetic particles added to improve the cleaning property is 30 to 50% by weight of the whole toner.
Is appropriate.

In addition, in order to widen the fixing area of the toner (the range of fixing and hot offset), it is also effective to set the conditions during kneading of the toner so that the binder resin gives an appropriate shear energy to obtain an area where the toner melting start temperature is optimum. It is. The softening point and outflow starting temperature of the toner melting range at this time were measured by an elevated flow tester.
° C and the outflow starting temperature is 115 to 135 ° C.

Conventionally, in the production of toner, a crosslinked component (measured as a THF (tetrahydrofuran) insoluble component)
By fixing the ratio of THF and the ratio of the soluble matter in THF,
The balance between grindability and hot offset has been achieved. Based on the molecular weight distribution, the relationship between grindability, fixability and hot offset can be separated into insoluble and soluble components by dissolving the binder resin in a solvent such as THF, and the soluble component is measured by GPC. can do.

Focusing on the peak positions and the component amounts of the molecular weight distribution of the THF-insoluble component and the soluble component, the THF-insoluble component has a disadvantageous effect on fixability, but is effective for hot offset.
If the amount of insolubles is too large, the load is too high when kneading the toner with a kneading machine, so that the supply amount of the material must be reduced, which results in poor productivity and easy variation in quality.

Although some toners using a binder resin having a molecular weight range of less than 1 × 10 ⁷ have been known, none of them has been satisfactory. As a result of research on these, the present inventors have already mentioned a little about grindability and fixability based on a new molecular weight distribution, hot offset, and the like, and have discovered the following facts. As a result, with respect to the environmental stability of charging, which is a problem of the polyester resin, the binder resin of the blend type of the polyester resin and the vinyl resin in the present invention is improved to suppress the humidity dependency, and to obtain a toner showing good charging characteristics. It has been reached.

Here, the measuring method by GPC will be described as follows. That is, the column was stabilized in a heat chamber at 40 ° C., and THF was flowed through the column at this temperature at a flow rate of 1 ml per minute as a solvent.
The measurement is performed by injecting 50 to 200 μl of the HF sample solution. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve created from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, P
less Chemical Co. Alternatively, Toyo Soda Kogyo Co., Ltd. has 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 , 8.6 × 10 ⁵ , 2 × 10 ⁶ ,
It is appropriate to use 4.48 × 10 ⁶ samples and to use at least about 10 standard polystyrene samples.

An RI (refractive index) detector is used as the detector. Although in this way is not to measure the molecular weight distribution of the toner, the detection of molecular weight ¹⁰⁷ or more in the current column is substantially difficult. On the other hand, experimentally G
The existence of a molecular weight range of 10 ⁷ or more, which is the detection limit of PC molecular weight, that is, a microgel component was found, and this molecular weight range affects the fixability, crushability, and offset. The microgel content can be determined by using a toner separation method. That is, a solvent insoluble in toner is added to THF, and the ratio of THF to the solvent may be determined while observing the molecular weight distribution.

At this time, fractionation was carried out at 25 ° C. using a mixed solvent of THF and isododecane. The ratio (volume ratio) of THF / isododecane is suitably 2 ± 0.5 / 3 ± 1.5, and the liquid in which the toner is dissolved at this ratio is the range for measuring the molecular weight of GPC. In addition, a test method for separating and separating the THF insoluble matter is performed as follows. Toner about 1.
0 g was weighed, and about 50 g of THF was added thereto.
Let stand for 4 hours. This is first separated by centrifugation and filtered at room temperature using JIS standard (according to P3801) 5 type C quantitative filter paper. Subsequently, the filter paper residue is an insoluble matter, and is represented by the ratio (wt%) between the used toner and the filter paper residue. Since carbon and other solids are present in this residue, it is separately determined by thermal analysis. In the case of a solvent for separation, THF may be changed to this solvent. The microgel content can be calculated by calculating the THF / isododecane soluble content and the THF insoluble content from the amount of the THF soluble component.

In the present invention, the polycarboxylic acid component (A)
Comprises a divalent carboxylic acid (A1) and, if necessary, a trivalent or higher carboxylic acid (A2). Specific examples of the divalent carboxylic acids (A1) include (1) maleic acid, fumaric acid, succinic acid, adipic acid, sebacic acid, malonic acid,
Aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as azelaic acid, mesaconic acid, citraconic acid and glutaconic acid; (2) alicyclic dicarboxylic acids having 8 to 20 carbon atoms such as cyclohexanedicarboxylic acid and methylmedic acid; (3) Aromatic dicarboxylic acids having 8 to 20 carbon atoms such as phthalic acid, isophthalic acid, terephthalic acid, toluenedicarboxylic acid, and naphthalenedicarboxylic acid; Alkyl or alkenyl succinic acids having 4 to 35 hydrocarbon groups; and anhydrides and lower alkyl (methyl, butyl, etc.) esters of these divalent carboxylic acids.

Among these, the above (1), (3),
(4) and anhydrides and lower alkyl esters of these dicarboxylic acids are preferred, and maleic acid, fumaric acid, isophthalic acid, terephthalic acid, dimethyl terephthalate, and n-dodecenyl (anhydride) succinic acid are more preferred.
(Anhydride) maleic acid and fumaric acid are preferred in terms of high reactivity, and isophthalic acid and terephthalic acid are preferred in terms of increasing the glass transition temperature of the polyester. Also,
Alkyl or alkenyl (anhydride) succinic acid has the advantage of improving the pulverizability of the toner.

Specific examples of the trivalent or higher polycarboxylic acids (A2) include (1) 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, and 1,3-dicarboxyl-2. -Methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,
7 to 7 carbon atoms such as 2,7,8-octanetetracarboxylic acid
(2) an alicyclic polycarboxylic acid having 9 to 20 carbon atoms such as 1,2,4-cyclohexanetricarboxylic acid; (3) 1,2,4-benzenetricarboxylic acid; 2,5-benzenetricarboxylic acid, 2,
5,7-naphthalenetricarboxylic acid and 1,2,4-
C9 to C20 aromatic polycarboxylic acids such as naphthalenetricarboxylic acid, pyromellitic acid and benzophenonetetracarboxylic acid; and anhydrides and lower alkyl (methyl, butyl, etc.) esters thereof. (A2)
When (3) is used, (3) and anhydrides and lower alkyl esters thereof are preferable among them, and in particular, 1,2,4-
Benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, and anhydrides and lower alkyl esters thereof are preferred in terms of cost and imparting offset resistance to the toner. The use ratio of (A2) in the polycarboxylic acid component (A) is usually 0 to 30 mol%, preferably 0 to 20 mol%,
More preferably, it is 0 to 10 mol%.

In the present invention, the polyol component (B)
Is an oxyalkylene ether of a novolak type phenol resin (B1), and if necessary, other dihydric alcohols (B1).
2) and other trihydric alcohols (B3).

The oxyalkylene ether (B1) of the novolak type phenol resin is a reaction product of the novolak type phenol resin (a) and the compound (b) having one epoxy ring in the molecule.

The novolak-type phenolic resin (a) includes phenols and aldehydes using an inorganic acid such as hydrochloric acid, phosphoric acid or sulfuric acid, an organic acid such as paratoluenesulfonic acid or oxalic acid, or a metal salt such as zinc acetate as a catalyst. And those produced by polycondensation with other compounds.

Examples of the phenols include phenols and substituted phenols having at least one hydrocarbon group having 1 to 35 carbon atoms and / or a halogen group as a substituent. Specific examples of the substituted phenol include cresol (ortho-form, meta-form or para-form), ethylphenol, nonylphenol, octylphenol, phenylphenol, styrenated phenol, isopropenylphenol, 3-chlorophenol, 3-bromophenol,
3,5-xylenol, 2,4-xylenol, 2,6
-Xylenol, 3,5-dichlorophenol, 2,4
-Dichlorophenol, 3-chloro-5-methylphenol, dichloroxylenol, dibromophenol,
2,4,5-trichlorophenol, 6-phenyl-2
-Chlorophenol and the like. Phenols are 2
More than one species may be used in combination.

Among these, phenol and a substituted phenol substituted with a hydrocarbon group are preferred, and among them, phenol, cresol, t-butylphenol and nonylphenol are particularly preferred. Phenol and cresol are preferred from the viewpoint of imparting price and offset resistance of the toner, and substituted phenol substituted with a hydrocarbon group represented by t-butylphenol and nonylphenol reduces the temperature dependence of the charge amount of the toner. preferable.
Aldehydes include formalin (formaldehyde solutions of various concentrations), paraformaldehyde, trioxane, hexamethylenetetramine and the like. The number average molecular weight of the novolak type phenol resin (a) is usually 30.
0-8000, preferably 450-3000, more preferably 400-2000.

The number average number of phenol nuclei in the novolak type phenol resin (a) is usually 3 to 60, preferably 3 to 20, and more preferably 4 to 15. Softening point (a) (JIS K2531; ring and ball method)
Is usually 40 to 180 ° C, preferably 40 to 150 ° C,
More preferably, it is 50 to 130 ° C. If the softening point of (a) is less than 40 ° C., blocking will occur at room temperature, making handling difficult. On the other hand, if the softening point exceeds 180 ° C., gelation is caused in the production process of the polyester resin, which is not preferable.

Specific examples of the compound (b) having one epoxy ring per molecule include ethylene oxide (EO),
Examples thereof include 1,2-propylene oxide (PO), 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, and epichlorohydrin. As (b), a glycidyl ether of an aliphatic monohydric alcohol having 1 to 20 carbon atoms or a monohydric phenol can also be used. Of these, EO and / or PO
Is preferred.

The number of moles of (b) added to 1 mole of (a) constituting the oxyalkylene ether (B1) of the novolak type phenol resin is usually 1 to 30 moles, preferably 2 to 15 moles, and more preferably 2.5 moles. The average number of moles of (b) added to one phenolic hydroxyl group in (a) is usually 0.1 to 10 mol, preferably 0.1 to 4 mol, more preferably 0.2 to 10 mol. ２2 mol.

The number average molecular weight of (B1) is usually from 300 to 1.
0000, preferably 350-5000, more preferably 450-3000. When the number average molecular weight of (B1) is less than 300, the offset resistance of the toner is not sufficient,
If it exceeds 10,000, gelation is caused in the production process of the polyester resin, which is not preferable. The hydroxyl value (total of alcoholic and phenolic hydroxyl groups) of (B1) is usually 10 to 550, preferably 50 to 500, more preferably 100 to 450 mgKOH / g. In addition, among the hydroxyl values, the phenolic hydroxyl value is usually 0 to 500, preferably 0 to 350, and more preferably 5 to 250 mgK.
OH / g.

As an example of the production method of (B1), if necessary, a compound (b) having one epoxy ring in the molecule is added to a novolak-type phenolic resin (a) in the presence of a catalyst (a basic catalyst or an acidic catalyst). The oxyalkylene ether of the novolak type phenol resin (B
1) is obtained. The reaction temperature is usually from 20 to 250 ° C., preferably from 70 to 200 ° C., and the reaction can be carried out under normal pressure, under pressure, or even under reduced pressure. The reaction can also be carried out in the presence of a solvent (eg, xylene, dimethylformamide, etc.) or other dihydric alcohols (B2) and / or other trihydric or higher alcohols (B3).

Other dihydric alcohols (B2) include
For example, (1) ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-
C2-C12 alkylene glycols such as butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, and 1,6-hexanediol; (2) diethylene glycol, triethylene glycol, dipropylene glycol Alkylene ether glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol;
(3) alicyclic diols having 6 to 30 carbon atoms such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; and (4) bisphenols such as bisphenol A, bisphenol F and bisphenol S;
(5) Alkylene oxides of the above bisphenols (E
O, PO, butylene oxide, etc.) 2 to 8 mol adducts. When (B2) is used, (1) and (5) are preferable, and (5) is more preferable. In the above (1), ethylene glycol increases the reaction rate, and 1,2-propylene glycol and neopentyl glycol are preferred from the viewpoint of low-temperature fixability. In the above (5), especially, EO of bisphenol A and / or
Alternatively, the addition of 2 to 4 moles of PO is preferred in that it gives the toner a good offset resistance.

Specific examples of other trihydric or higher alcohols (B3) include (1) sorbitol, 1,2,3,6-
Hexane tetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,2
Aliphatic polyhydric alcohols having 3 to 20 carbon atoms such as 5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, and trimethylolpropane;
(2) Aromatic polyhydric alcohols having 6 to 20 carbon atoms such as 1,3,5-trihydroxylmethylbenzene; and alkylene oxide adducts thereof. When (B3) is used, among these, the compound of (1) is preferable, and among them, glycerol, trimethylolpropane, and pentaerythritol are preferable from the viewpoint of inexpensiveness.

(B1) and (B1) in the polyol component (B)
The composition ratios of 2) and (B3) are usually (B1) 2
-100%, (B2) 0-98%, (B3) 0-20
%, Preferably (B1) 4 to 70%, (B2) 30 to 9
6%, (B3) 0-10%, more preferably (B1) 4
-50%, (B2) 50-96%, (B3) 0-5%, and B1 + B2 + B3 = 100%.

The vinyl resin (vinyl polymer) which is blended with the polyester resin in the present invention in an amount of 30% by weight or less based on the whole binder resin, contains 50 to 100% by weight, preferably 60% by weight, of styrene as a component thereof.
It is preferable to use a vinyl copolymer polymerized by about 90% by weight. When the styrene copolymerization amount is less than 50% by weight, the heat melting property of the toner is inferior, and as a result, the fixing property tends to be insufficient.

In the present invention, vinyl monomers other than styrene which are components of the vinyl polymer include styrene such as α-methylstyrene, p-methylstyrene, p-tert-butylstyrene and p-chlorostyrene. Derivatives,
Methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate , Glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxytriethylene glycol methacrylate,
Methoxydipropylene glycol methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyl methacrylate Ethyl, N-vinyl-2-pyrrolidone methacrylate, methacrylonitrile, methacrylamide, N-methylol methacrylamide, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, methacrylic acid-
2-hydroxy-3-phenyloxypropyl, diacetone acrylamide, acrylic acid, methyl acrylate,
Ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, acrylic acid Methoxyethyl, propoxyethyl acrylate, butoxyethyl acrylate, methoxydiethylene glycol acrylate, ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, acrylic acid Phenoxydiethylene glycol, phenoxytetraethylene glycol acrylate, benzyl acrylate, acrylic acid Rohekishiru, tetrahydrofurfuryl acrylate, acrylic acid dicyclopentenyl, dicyclopentenyloxyethyl acrylate, N-
Vinyl-2-pyrrolidone, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, glycidyl acrylate, acrylonitrile, acrylamide, N-methylol acrylamide, diacetone acrylamide, 1 such as vinylpyridine
A vinyl monomer having one vinyl group in the molecule is used as a main component. In addition, a reaction product of divinylbenzene, glycol and methacrylic acid or acrylic acid, for example, ethylene glycol dimethacrylate, 1,3-butylene glycol Methacrylate, 1,4-butanediol dimethacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, Tripropylene glycol dimethacrylate, neopentyl glycol hydroxypivalate diester methacrylate, trimethylolethane trimethacrylate, Limethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythrit tetramethacrylate, trismethacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate, tris (methacryloyloxyethyl) isocyanurate, ethylene glycol diacrylate, 1 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate , Polyethylene glycol diacrylate, tripropylene glycol diacrylate, Dorokishipibarin acid neopentyl glycol diacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate,
Tris (methacryloyloxyethyl) isocyanate, a half esterified product of glycidyl methacrylate and methacrylic acid or acrylic acid, a half esterified product of bisphenol type epoxy resin and methacrylic acid or acrylic acid,
A vinyl monomer having two or more vinyl groups in one molecule, such as glycidyl acrylate and methacrylic acid or half-esterified acrylic acid, is used.

Among these, preferred vinyl monomers are those having one vinyl group in one molecule, such as styrene, styrene derivatives, methacrylates, and acrylates. Particularly preferred are styrene and alkyl esters of methacrylic acid or acrylic acid having 1 to 5 carbon atoms in the alkyl group.
As the vinyl monomer having two or more vinyl groups in one molecule, divinylbenzene, dimethacrylate of methylene glycol having 2 to 6 carbon atoms, diacrylate and the like are preferable.

These monomers are blended so that the total is 100% by weight. Among them, the amount of the vinyl monomer having two or more vinyl groups in one molecule is preferably 0.1 to 1% by weight.

The above-mentioned monomer or monomer mixture can be polymerized by any method such as suspension polymerization, solution polymerization, emulsion polymerization, bulk polymerization and the like. From the point of view, it is preferred to produce by aqueous suspension polymerization.

The radical initiator used for the polymerization of the above monomer or monomer mixture includes benzoyl peroxide,
2-ethylhexyl perbenzoate, lauroyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, 4,4,6-trimethylcyclohexanone Di-tert-butylperoxyketal, cyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide,
Peroxide radical initiators such as cyclohexanone di-tert-butyl peroxy ketal, 2-octanone di-tert-butyl peroxy ketal, acetone di-tert-butyl peroxy ketal, diisopropyl benzene hydroperoxide, 2,2'-azobisiso Butyroitrile, 2,2′-azobis (2,4-dimethylpareronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate, There are azobis-based radical initiators such as 1,1′-azobis (cyclohexane-1-carbonitrile). These are preferably 0.01 to 20% by weight, particularly preferably 0.1 to 20% by weight, based on the total amount of the monomers.
Use 1 to 10% by weight.

In addition, butyl mercaptan, octyl mercaptan, dodecyl mercaptan, methyl 2
-Mercaptopropionate, ethyl 2-mercaptopropionate, butyl 2-mercaptopropionate, octyl 2-mercaptopropionate, pentaerythritol tetra (2-mercaptopropionate),
Uses radical polymerization molecular weight regulators such as mercaptans such as ethylene glycol di (2-mercaptopropionate) and glycerin tri (2-mercaptopropionate), and halogenated hydrocarbons such as chloroform, bromoform and carbon tetrabromide. You can also. These molecular weight modifiers are preferably used in an amount of 0 to 3% by weight based on the total amount of the monomers.

When carrying out aqueous suspension polymerization, partially saponified polyvinyl alcohol, alkyl cellulose, hydroxy-alkyl cellulose, carboxyalkyl cellulose, polyacrylamide, polyvinylpyrrolidone,
Water-soluble polymer dispersants such as polyacrylic acid and its alkali metal salts, polymethacrylic acid and its alkali metal salts,
Insoluble inorganic dispersants such as calcium phosphate, hydroxyapatite, magnesium phosphate, magnesium pyrophosphate, calcium carbonate, barium sulfate, and hydrophobic silica can be used. The dispersant is preferably used in an amount of 0.0001 to 5% by weight based on the aqueous medium in the case of a water-soluble polymer dispersant, and 0.01 to 15% by weight in an aqueous medium in the case of a poorly soluble inorganic dispersant. preferable.

By the way, a toner using a polyester resin as a binder resin has a change in charge amount at high humidity and a slow rise of charge, and the like.
Such inconveniences have been reported. Slow charging rise may cause soiling. Therefore, it is necessary and indispensable to prevent these problems and obtain a clear image.

Therefore, in the toner of the present invention, the binder resin (polyester resin, polyester resin blended with vinyl resin) has a Tg of 50 to 65 ° C., an acid value of 1 to 5 mg KOH / g, and preferably 1 to 5 mg KOH / g. ~ 3mgKOH / g, hydroxyl value is 30 ~ 80mgK
It is advantageous to use OH / g, preferably 30 to 60 mg KOH / g. Tg of binder resin is DS
The endothermic peak in the C curve is preferably in the range of 50 to 65 ° C. If the Tg is lower than 50 ° C., the toner may be solidified during storage, and if the Tg is higher than 65 ° C., the low-temperature fixability may not be satisfactory. Particularly, in recent years, there is a tendency that a binder for low-temperature fixing is desired in order to keep power consumption low. Therefore, if storage stability can be ensured, Tg is preferably lower.

Regarding charging, it is desirable to select a binder resin that does not easily adsorb moisture in the air in order to minimize environmental fluctuations. For this reason, the novolak-type phenol resin used in the present invention is less likely to adsorb moisture in the air than the other polyol components, and is suitable. Using this material, the acid value is 5 mgKOH / g or less,
By adjusting the hydroxyl value to 30 to 80 mgKOH / g, adsorption of moisture can be further prevented, and 3000 ppm or less can be achieved. When the content is 3000 ppm or less, the environmental stability is further improved.

The acid value is preferably as low as possible. However, it is difficult to obtain an acid value of 1 or less from the viewpoint of the polyester reaction.
OH / g. The hydroxyl value is also desirably suppressed to 80 mgKOH / g from the industrial limit of 30 mgKOH / g for the esterification reaction. The region of 30 mgKOH / g or less is an unconfirmed region, and the same as the acid value, 80 mgKOH / g or less, preferably 60 mgKOH / g or less is required to suppress the water content of the binder resin. By adjusting the acid value and the hydroxyl value to appropriate ranges, the water content becomes 3000p.
pm or less.

Here, the method for measuring the moisture content of the binder resin will be described as follows. First, add 200 resin
It is pulverized to not more than μm and stored for 24 hours in an environment of 30 ° C. and 60% RH. The water content of this resin is measured using a vaporizer of a Karl Fischer moisture titrator. In addition, in order to obtain a required amount of charge, the effect of reducing the charge control agent (inexpensive toner) is also provided.

The binder resin of the toner obtained as described above is appropriately melt-mixed with a colorant and / or magnetic powder and, if necessary, a charge control agent and other additives to form a toner for developing an electrostatic image. can do.

As the coloring agent in the present invention, carbon black, in particular, having a specific surface area of 100 to 15 as measured by BET.
Those having a pH of less than 7 at 0 m ² / g are used. The amount of carbon black contained in the toner is appropriately selected and used in the range of 1 to 50%. The specific surface area is a measure of the particle size of carbon, and the larger the measured value, the smaller the particle size. In order to disperse uniformly in the binder resin with a small particle size, the particle size is desirably small, and a specific surface area of 100 m ² / g or more is required. on the other hand,
When the specific surface area is larger than 150 m ² / g, aggregates of carbon particles are likely to be generated, and the dispersed particle diameter in the toner becomes large. Further, the pH of carbon black is affected by an oxygen compound present on the carbon surface, and has an effect of increasing compatibility with the binder resin used in the present invention. Therefore, the carbon black used in the present invention must contain an oxygen compound, and has a pH of acidic, that is, less than 7, preferably 6 or less.

As the charge controlling agent, nigrosine dye, fatty acid-modified nigrosine dye, metal-containing nigrosine dye, metal-containing fatty acid-modified nigrosine dye, 3,5-di-tert-
A chromium complex of butylsalicylic acid or the like can be used, and is usually used in the toner in an amount of 0 to 20% by weight.

A wax having a melting point of 70 ° C. to 170 ° C. is used as a release agent. Specific examples of the release agent include:
Examples thereof include carnauba wax, montan wax, sasol wax, paraffin wax, low molecular weight polyethylene, low molecular weight polypropylene, and ethylene-vinyl acetate copolymer. These are added to the toner in the range of 1 to 10% by weight.

The addition of wax gives mold releasability and certainly improves hot offset, but on the other hand, there is a problem in compatibility with the resin, and as the amount increases, the developability deteriorates. In addition, since spent with a carrier also occurs, the charge amount becomes insufficient and the charge becomes unstable. For this reason, it is preferable that the amount of the wax is as small as possible. However, the releasability can be obtained without causing the occurrence of carrier spent or a shortage of charge.

It was found that the wax in the toner became 2 μm or less by kneading with high shearing energy during kneading with the particle size of the wax used being 100 μm or less.
When the particle size is 2 μm or less, even if 10% is added to the toner, the above-mentioned side effect due to the wax does not occur, and the effect of the releasability can be obtained. The wax having a particle diameter of 2 μm or less was obtained by checking the cross section of the toner with a TEM photograph.

As other additives, silica powder, hydrophobic silica powder, polyolefin, paraffin wax, fluorocarbon compound, fatty acid ester, partially saponified fatty acid ester, fatty acid metal salt and the like can be used. 0.1 to 5% by weight is used in the toner.

The toner of the present invention can be used for either a dry one-component developer or a two-component developer. As a magnetic material in the case of a one-component developer, alloys containing ferromagnetic elements such as ferrite, magnetite, etc., iron, cobalt, nickel, etc., or compounds containing no ferromagnetic elements, but appropriately heat-treated Alloys that have become ferromagnetic by doing so, for example, alloys of the type called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum or manganese-copper-tin, or chromium dioxide. . The magnetic material has a particle size of 0.3
It is uniformly dispersed in the binder resin in the form of a fine powder of 〜30 μm. The content of the magnetic particles is 20 to 70 in the toner.
% By weight, preferably 40 to 70% by weight.

The particle size of the magnetic substance added to the toner in order to improve the adjustment or cleaning properties of the one-component magnetic toner is 0.1 μm or less, and is finely dispersed in a binder resin, preferably together with a wax. The magnetic material to be charged is 0.1
μm or less is used, but if we look at the examples so far, the magnetic material is not sufficiently differentiated even if 0.1 μm or less is used, and becomes an aggregate. there were. However, the condition was such that the magnetic material was sufficiently dispersed due to the viscosity of the resin (polyester resin) and high energy shear during kneading. The content of the magnetic substance in the one-component magnetic toner is 20 to 70% by weight, preferably 40 to 70% by weight in the toner.

The toner in the two-component developer is composed of a colorant, a binder resin, and a charge control agent as main components, as is generally used.

In order to use the toner composition according to the present invention by a cascade developing method, a magnetic brush developing method, or the like, the composition must have an average particle size expressed by weight percentage of about 30 μm or less. It is desirable that this average particle size be between about 4 and 20 μm to produce results. For use in powder cloud development, particles having a particle size slightly smaller than 1 μm are desirable.

[0071] Coated and uncoated carriers used in cascade development, magnetic brush development, and the like are well known, but the carrier particles must be coated so that the toner powder adheres to and surrounds them. The carrier particles may be formed of any suitable material so long as the toner powder acquires a charge of opposite polarity to that of the carrier particles when brought into intimate contact with the toner powder. Accordingly, the toner compositions of the present invention can be used in combination with conventional carriers to develop electrostatic latent images on any suitable electrostatic latent image bearing surface, including conventional photoconductive surfaces. Is done.

(Toner production method)
As a method for obtaining a content of ２０20% by weight, there is a method of cutting molecules in the molecular region of the THF-insoluble portion by mechanical energy. This method uses a THF insoluble content of 10 to 40.
A binder resin of a polyester resin and a vinyl resin, which are contained by weight%, is kneaded while mixing carbon black, a charge control agent, a magnetic substance, and other additives and applying mechanical shear energy.

In the present invention, it is necessary to use a binder resin having a small particle diameter in advance in a raw material powder mixing step, which is a step prior to the melt kneading step, a so-called pre-mixing step. As a method for reducing the particle size of the binder resin, known equipment and methods such as a jet air mill and a mechanical pulverizer are used. As a method of mixing the above-mentioned binder resin having a reduced particle size with a coloring agent, a well-known powder mixer such as a V blender or a Henschel mixer is used, and the mixture is pre-mixed by the above-described mixing ratio and mixing method.

In general, melt kneading is performed to further reduce the particle size of the pre-mixed binder resin and other raw materials and to uniformly disperse them. As the kneader, a hot roll, a pressure kneader, a Hanbury mixer, a single-screw or twin-screw continuous kneader or the like is generally used to knead at 100 to 200 ° C. In the case of such kneading, there is an area where molecules are cut by mechanical shear energy. This is mainly governed by the viscosity during kneading. The viscosity is suitably 10 ⁴ to 10 ⁷ poise. When kneaded at a viscosity lower than this viscosity range, molecules are not easily cut, and THF insoluble components remain in the toner. Conversely, when kneaded with a high viscosity, in addition to being not dispersed with other materials, there are cases where the load on the machine is large and the machine is damaged. It is considered that the molecular cleavage is caused by the cleavage of a polymer having a network structure having a weight average molecular weight of about 1 × 10 ⁶ or more. Looking at the molecular weight distribution before and after kneading, the molecular weight range of about 1 × 10 ⁴ or less has not changed. Cleavage of this molecule is difficult to obtain synthetically.

As a toner characteristic, a molecular weight in this range is effective for hot offset and filming. However, on the other hand, it works in a disadvantageous way to grindability and fixability,
In order to improve the pulverizability and fixing property, it is desirable to define the molecular weight distribution after kneading. That is, the mixture is kneaded within the above-mentioned viscosity range, has a main peak in the region of 2,000 to 10,000 in GPC, and has a molecular weight (Mw) of 10,000 or less in the range of 50 to 10,000.
By containing 70% by weight, fixability and pulverizability are improved. Particularly, a component having a low molecular weight (Mw) is preferable.
2,000 to 10,000, preferably 2,000 to 4,000
The one with the main peak is good.

When the vinyl resin occupies more than 30% by weight of the binder resin in the present invention, the resistance to PVC is reduced and the fixability is also deteriorated. For environmental stability, vinyl resin, especially styrene, mainly acrylic, methacrylic,
Alternatively, a copolymer with butadiene increases hydrophobicity and is more environmentally stable than polyester alone. The vinyl resin is preferably used in an amount of 30% by weight or less in consideration of PVC resistance, charging environment stability, and fixability.

The viscosity of 1 × 10 ⁴ to 1 × 10 ⁷ poise during kneading is suitable for dispersing the wax component to 2 μm or less.
Resin that can be used for toner other than vinyl resin such as epoxy resin and phenol resin
Can also be used at 30% by weight or less.

Next, a method for obtaining a toner in which a polyolefin is finely dispersed at 2 μm or less will be described. The dispersibility of the polyolefin wax becomes very good due to the presence of the microgel component in the binder resin. This is because the microgel component has a great influence on the rheological properties. That is, a high-molecular polymer is a substance that exhibits typical viscoelastic behavior. It has a branched structure formed by cutting a cross-linked resin molecule of polyester or vinyl resin, and has a large storage modulus G 'during kneading. The temperature at the time of kneading the toner is generally in the range of 100 to 200 ° C., but even in this range, the polymer having a branched structure does not flow and has an elastic modulus of at least about 10 ³ dyne / cm ^2. Is known to be maintained (Oka
Koten, "Introduction to Rheology," p. 83, published by the Industrial Research Council.)
The elastic modulus relates to the cohesive force of the substance, and the polyolefin wax is kneaded in a state of being subjected to the cohesive force from the entire toner phase including the microgel component, so that strong shear is applied and the dispersibility is improved.

On the other hand, when a system containing no subpeak, that is, a linear polymer is used as the binder resin,
It is known that under general kneading conditions, the resin flows and the elastic modulus goes to zero. Until now, several inventions using polyolefin waxes have been proposed, but in most cases, they have poor compatibility with the binder resin and result in poor dispersion. However, since a system in which a polyester resin and a vinyl resin are blended and a microgel component is contained exhibits viscoelastic behavior suitable for kneading, the polyolefin wax is finely dispersed at 2 μm or less.

The softening point of the toner used in the present invention is desirably in the range of 70 to 85 ° C. If the softening point is lower than 70 ° C., the storage stability of the toner is lowered, and
When the ratio exceeds, the low-temperature fixability of the toner tends to deteriorate. Also, the outflow start point moves in the same way as the softening point,
It is desirable to be in the range of 15 to 135 ° C. These two characteristics are satisfied with each other, and the fixing property is secured. Here, the softening point is an elevated flow tester “CF” manufactured by Shimadzu Corporation.
Using T-500 type ", the measurement condition was a load of 10 kg / c.
Ts calculated from the measuring instrument as m ² , nozzle diameter 1 mm, nozzle length 1 mm, and heating rate 10 ° C./min was taken as the softening point, and Ttb was taken as the outflow start point.

[0081]

Next, the present invention will be described more specifically with reference to examples. Parts here are by weight.

Table 1 shows the compositions and properties of the polyester resins used in the examples and comparative examples, and Table 2 shows the properties of the colorants.

[0083]

[Table 1]

(Abbreviations of raw materials shown in Table 1) (1) Glycol A: polyoxypropylene (2, 2)
-2,2-bis (4-hydroxyphenyl) propane (hydroxyl value 315) (2) Glycol C: poly (oxyethylene-propylene) -bis- (4-hydroxyphenyl) methane (hydroxyl value 320) (3) glycol D: polyoxypropylene (3, 2)
-2,2-bis (4-hydroxyphenyl) propane (hydroxyl value: 275) (4) TPA: terephthalic acid (5) DSA: dodecenyl succinic anhydride

[0085]

[Table 2] : The specific surface area was measured by a nitrogen adsorption method (BET method). : The particle diameter was measured by an electron microscope. : Volatile content is the weight loss when heated at 950 ° C. for a fixed time.

Examples 1 to 8 and Comparative Examples 1 to 3 Binder resin: 100 parts of polyester resins I to IV shown in Table 1 Colorant: carbon black shown in Table 2, 10 parts Charge control agent: zinc salt of salicylic acid derivative 4 parts Release agent: Carnauba wax 5 parts In the above-mentioned raw material formulation, powder was mixed by a super mixer according to the production method shown in Table 3, melt-kneaded with two rolls, and then cooled and roughly crushed using a hammer mill. Then, the resultant was finely pulverized by a jet air pulverizer and then classified to obtain a toner having an average particle diameter of 11 μm. Each evaluation was performed by the following methods, and the evaluation criteria were as follows: ：: more excellent, ：: good,
Δ: no improvement effect, ×: worse.

(Image Evaluation Method) 50 parts of a toner having a particle size of 10 to 11 μm and 950 parts of EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) were mixed and sufficiently shaken to obtain a developer. Using this developer, a high-speed copying machine (FT82 manufactured by Ricoh Company)
00) to perform image evaluation. (Minimum fixing temperature) An unfixed image is created by an image forming apparatus (with a fixing unit removed) and passed through a separately prepared hot roll fixing device. At this time, the fixing roll temperature is arbitrarily changed and the fixing state is checked. In the check, the fixed image portion is rubbed with cotton, and the temperature at which the cotton is not stained with the toner is defined as the fixing temperature. (Hot offset temperature) When an image is formed by an image forming apparatus, toner adhering to a hot roll is passed through blank paper, and it is checked whether toner is stained on the paper passing paper. Judgment was expressed by the upper limit of the heat roll temperature at which no toner stain was observed. (Stability of Charging Environment) The charging at high temperature and high humidity (30 ° C., 90% RH) and the charging at low temperature and low humidity (10 ° C., 30% RH) are compared and evaluated based on the fluctuation range. (Toner pulverizability) The kneaded toner was roughly pulverized by a hammer mill and finely pulverized by a jet air mill. At this time, the supply amount required to obtain a volume average particle size of 10 μm was measured and used as an index of pulverizability. The discharge air pressure is 5.0 kg / cm ²
And

[0088]

[Table 3]

From the results in Table 3, it is found that Examples 1 to 6 have fixing properties,
It can be seen that the balance between hot offset property, pulverizability, charging environment stability and image quality is good. On the other hand, in Comparative Examples 1 and 2, in which no binder resin having a small particle diameter was used, fogging occurred, and the amount of microgel was large, and the fixing temperature was high.

Examples 7 and 8 and Comparative Example 3 A developing toner was prepared in exactly the same manner as in Example 3, except that 25 parts of 100 parts of the binder resin were changed to the vinyl resin (A) shown in Table 4. This toner was evaluated in the same manner as in Example 3. Table 5 shows the results.

[0091]

[Table 4]

[0092]

[Table 5]

[0093]

【The invention's effect】

(1) By using the binder resin having the particle diameter described in the first aspect, a micro-pigment-dispersed toner having excellent image quality in which a colorant is uniformly dispersed with a small particle diameter in the resin can be obtained. (2) The low-temperature fixing property and the hot offset property are improved by using the binder resin described in claim 2 and not containing the resin THF insoluble matter in the toner but containing a microgel content of 5 to 20%. A toner having a wide fixing temperature range can be obtained. (3) By using the binder resin described in claim 3, the effect of (2) is further improved. (4) By using the binder resin described in claim 4, a toner having a wide temperature range of low-temperature fixing and hot offset can be obtained. (5) By using the colorant described in claim 5, the effect of the above (1) is further improved. (6) The toner manufactured according to the mixing ratio described in claim 6 can further improve the effect of (1). (7) By producing the toner by the method described in claim 7, the effects (1) to (6) can be obtained even more efficiently.

Claims (7)

[Claims] 1. An electrostatic charge image developing toner comprising a binder resin and a colorant dispersed therein, wherein the binder resin has a volume average particle size of 5 to 20 μm. 2. The binder resin is a polyester resin having a polycarboxylic acid component (A) and a polyol component (B) as constituent units, and at least a part of the polyol component (B) is an oxyalkylene of a novolak-type phenol resin. 2. The electrostatic image developing toner according to claim 1, wherein the toner is an ether (B1) and is present in the toner in the following conditions (a) and (b). (A) not containing tetrahydrofuran insoluble matter; (b) containing 5 to 20% by weight of a component having a molecular weight of 1 × 10 ⁷ or more. 3. The binder resin according to claim 1, wherein the binder resin comprises a polyester resin having a polycarboxylic acid component (A) and a polyol component (B) as constituent units and a vinyl resin blended. 3. The toner for developing an electrostatic image according to 2. 4. The binder resin has a molecular weight distribution of 2,000 to 100 as determined by gel permeation chromatography (GPC) of the tetrahydrofuran dissolved portion.
00 having a main peak and a molecular weight of 100
The toner for developing an electrostatic image according to any one of claims 1 to 3, wherein the content of the toner of not more than 00 is 50 to 70% by weight. 5. The colorant is carbon black,
The specific surface area measured by the BET is 100 to 150 m ² /
The toner according to claim 1, wherein the pH is less than 7 in g. 6. A binder resin and a colorant, a charge control agent,
Melt and knead wax and other raw materials, pulverize after cooling,
In the method of producing a toner by classifying, the binder resin according to any one of claims 1 to 4 is added to 1 part by weight of the coloring agent according to claim 5 in a premixing step of raw materials prior to the melt-kneading. A method for producing a toner for developing an electrostatic image, comprising mixing powder in a proportion of about 20 parts by weight. 7. A binder resin and a colorant, a charge control agent,
Melt and knead wax and other raw materials, pulverize after cooling,
In the method for producing a toner by classifying, the colorant according to claim 5 and the binder resin according to any one of claims 1 to 4 are shown in claim 6 in a premixing step of raw materials prior to the melt-kneading. The mixture obtained by pulverizing and mixing according to the ratio is used as a masterbatch for colorant high dispersion, and a binder resin having a volume average particle diameter of 20 μm or more and other materials are further mixed with the masterbatch. Production method.