JP2885249B2 - Electrophotographic toner composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic toner composition used for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

2. Description of the Related Art In electrophotography, a copying speed tends to increase with an increase in the amount of information to be processed in recent years. Therefore, the number of copies tends to increase in high-speed photography,
Needless to say, the toner is completely fixed on the paper, and the copied image is expected to be clear and of the same quality from the first sheet to tens of thousands of sheets.
However, conventionally, improvements relating to problems that occur after toner adheres to paper, such as improvements in offset properties and low-temperature fixing properties, have been mainly promoted. However,
It cannot be said that much consideration has been given to the fact that toner must adhere to paper at a uniform and constant density for each copy. The chargeability of the toner is an important factor in determining the amount of toner adhering to paper, and it is known that the image density is controlled by this mechanism. However, for example, in a two-component developer, triboelectric charging occurs due to friction between the toner and the carrier. For this reason, aggregates of colorant fine particles such as carbon black in the toner and undispersed materials of the charge control agent are separated, often causing carrier contamination and photoconductor contamination.

In addition, it also causes obstacles such as undercoating, changes in image density, and deterioration of images due to scratches on the photoconductor. Attempts have been made to solve such obstacles by a combination of conditions such as the temperature during kneading, the residence time, the type of kneader screw, the kneading conditions such as the rotational speed, and the method of dispersion. However, in spite of these contrivances, the solution has not yet been solved, for example, the characteristics of the toner fluctuate for each production.

For example, the European P provided earlier by the inventors
According to atent Publication No. 323513, the binder is a non-crosslinked polymer or a mixture thereof, and the number average molecular weight (Mn) of the binder is 2,000 to 15,000 and the Z average molecular weight (Mz) is 400,0.
00 or more, the Z average molecular weight / number average molecular weight (Mz / Mn) is 50
It has been found that by setting the value to 600, a toner composition having a small change in the amount of charge during copying has excellent fixability at high speed and at low temperature.

However, even when the relationship between the Z-average molecular weight and the number-average molecular weight is maintained, a phenomenon still occurs in which the toner varies among product lots. Among these phenomena, it was confirmed that a difference was observed in each bag packed from a large-capacity storage container such as a silo, or a difference was caused due to a change in the setting of the crushed particle size. Further, as shown in the above invention, when a small amount of a crosslinked polymer is contained, there is a drawback that a large change in charge amount is exhibited.

The present inventors have found that these problems are necessary for melting and kneading the colorant, the charge controlling agent and the like and the binder with heat, that is, 1) necessary for loosening aggregates of the colorant and the charge controlling agent. High viscosity conditions and 2) low viscosity necessary for wetting the loosened aggregate surface with a binder and improving uniform dispersibility, that is, the flow conditions are the premixing stage before kneading and the mechanical conditions during kneading. Thought that it would be difficult to achieve both just by changing As a result, the Mz that governs the viscosity of the adhesive was increased and the Mn that governed the ease of flow was made specific, and the difference in performance of each packaging unit of the binder was due to the segregation of the binder. It was found that the average particle size of each bag was too large, and that the amount of fine powder was too large.

In addition, it was mistaken in the past that it was considered ideal to have a uniform particle size with both large and small particle sizes cut off. It has also been found that it is necessary to mix both the large particle size particles and the small particle size particles in the particles, and that it is necessary to be careful not to shift to a specific particle size due to segregation or the like.

In addition, by adjusting the particle size of the binder to a specific range and then obtaining a toner through a pre-mixing and kneading process, the colorant and the charge controlling agent are uniformly dispersed, and further, there is no aggregate, It has been found that a toner composition which maintains excellent image quality even during long-time copying excellent in stability can be obtained. Further, in the prior art, the viscosity change during kneading due to molecular cutting or the like was large, and it was difficult to uniformly disperse the colorant, the charge controlling agent, etc., but it is possible to contain a small amount of a crosslinked polymer. I also found that.

DISCLOSURE OF THE INVENTION An object of the present invention is to elucidate and improve what causes the above-mentioned problems, and at the same time, even if a binder containing a small amount of a crosslinked product is used, it is necessary to use a binder for each toner production lot. An object of the present invention is to obtain an improved toner composition having no variation and having a small change in the amount of charge during copying.

The object of the present invention is to provide a toner composition for electrophotography, which comprises a binder and a colorant as main components, and preliminarily mixing and dispersing these main components, kneading, pulverizing, and classifying. As a binder before mixing and dispersion, 70% by weight or more of the binder is soluble in tetrahydrofuran (hereinafter abbreviated as THF), and the number-average molecular weight (Mn) of the THF-soluble portion measured using THF is measured. 2,000 to 15,000, Z-average molecular weight (Mz) 40
0,000 or more, and the binder particle diameter D ₇₅ is 2.5 mm or less, D ₂₅
Is adjusted to be not less than 0.15 mm and D ₇₅ / D ₂₅ is not less than 1.5.

In the above, D ₂₅ and D ₇₅ are cumulative from the smaller particle size in the cumulative particle size distribution curve, and the cumulative weight% is 25%.
The particle size corresponding to weight% is D ₂₅ , and the particle size corresponding to 75 weight% is D ₇₅ .

Best Mode for Carrying Out the Invention The binder in the present invention has a Mz of 400, in order to obtain a high viscosity necessary for loosening aggregates of a coloring agent and a charge controlling agent.
000, particularly preferably 500,000 or more. Mz is 400,000
If less, the effect of loosening the aggregates is small. The upper limit of Mz is not particularly limited, but is usually 400,000 or less.

On the other hand, the binder is 70% by weight, preferably 75% by weight in THF.
As described above, it is necessary to be soluble, and if it is less than 70% by weight, molecular breakage during kneading increases, and it is difficult to always obtain a toner of stable quality.

Mn should be between 2,000 and 1 to wet the surface of the colorant and charge control agent and to obtain the necessary fluidity to improve the uniform dispersant.
5,000, particularly preferably in the range of 2,000 to 10,000. That is, when the viscosity is less than 2,000, the viscosity at the time of kneading is too low, and the effect of loosening the aggregates of the colorant and the charge controlling agent is small.

The particle size of the binder is most important in the present invention. That discharge, even if the thermal properties of the binder suitable for how kneading, the particle size D ₇₅ is 2.5mm binder, without being completely melted during kneading large case exceed 2mm optionally The resulting binder is produced. For this reason, there is a phenomenon in which the coloring agent and the charge controlling agent are not taken into the binder but are localized. As a result, the uniform dispersant is remarkably damaged, the background is soiled, and in a severe case, the photoreceptor is damaged, and furthermore, a streak-like image disorder appears. On the other hand, when D ₂₅ is as small as 0.15 mm, and in some cases less than 0.17 mm, the uniform mixing of the binder with the colorant or the charge controlling agent in the pre-mixing before kneading is improved. However, it is easy to spin inside the kneader, and the force required to sufficiently loosen the aggregates of the colorant and the charge controlling agent is insufficient. As a result, agglomerates of the colorant and the charge controlling agent remain, and the raw material supply speed to the kneader becomes uneven, resulting in a large fluctuation in quality. Further, during continuous operation with a copying machine, an electrophotographic printer, a facsimile, or the like, the image is not stable, or if the image is severe, filming occurs on the photoconductor and the image is disturbed. As described above, the particle size of the binder has a large effect on the pre-mixing and kneading during the production of the toner. Therefore, if the particle size is too large or too small, the uniformity of the toner components is adversely affected.

For these reasons, it is essential that the binder particles have a wide particle size distribution and a mixture of large and small particles. That is, to satisfy such conditions, D ₇₅ / D ₂₅
Is 1.5, more preferably 1.8 or more. D ₇₅ / D ₂₅ 1.5
Smaller, that is, if the particle size distribution is too narrow, can be satisfied both the keeping it and uniformity to eliminate agglomerates of the colorant and charge control agent the magnitude of the average particle diameter (D ₅₀₎ In addition, it is not possible to secure the charging stability in long-time copying. The particle size of the binder for obtaining the effect of the present invention is obtained by sieving the resin mass constituting the binder into a pulverizer such as a chopper mill or a hammer mill so that a resin having a certain particle size or more does not pass therethrough. Of fine particles of the resin powder passing through the pulverizer can be obtained by air classification or by cutting with a sieve.

The resin constituting the binder used in the present invention is, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, cyclohexyl acrylate, lauryl acrylate, stearyl acrylate, benzyl acrylate, Acrylic esters such as furfuryl acrylate, tetrahydrofurfuryl acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate, dimethylaminomethyl acrylate, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, Propyl methacrylate, butyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, meth Methacrylates such as furfuryl acrylate, tetrahydrofurfuryl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, dimethylaminomethyl methacrylate, and dimethylaminoethyl methacrylate , Vinyl toluene, α-methylstyrene, chlorostyrene, aromatic vinyl monomers such as styrene, unsaturated dibasic acid dialkyl esters such as dibutyl maleate, dioctyl maleate, dibutyl fumarate, dioctyl fumarate,
Vinyl acetates such as vinyl acetate and vinyl flopionate; nitrogen-containing vinyl monomers such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as acrylic acid, methacrylic acid and cinnamic acid; maleic acid, maleic anhydride and fumaric acid , Unsaturated dicarboxylic acids such as itaconic acid,
Monoesters of unsaturated dicarboxylic acids such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monooctyl fumarate, styrene sulfonic acid, acrylamide, methacrylic acid Amide, N-substituted acrylamide, N-substituted methacrylamide, other monoolefinically unsaturated compounds such as acrylamidepropanesulfonic acid, divinylbenzene, divinyl compounds such as (poly) ethylene glycol diacrylate, (poly) ethylene glycol dimethacrylate, Butadiene, chloroprene, neoprene, a polymer or copolymer of a conjugated diolefin unsaturated monomer such as isoprene is appropriately selected and used, but an acrylate resin, Tacrylic acid resin, styrene resin, acrylic ester, styrene copolymer resin, methacrylic ester, styrene copolymer resin, acrylate ester, methacrylic ester, styrene copolymer resin, fumaric ester, styrene copolymer resin, maleate ester , Styrene copolymer resin, styrene, butadiene copolymer resin and the like are preferable.

In order to make the Z-average molecular weight of the binder of the present invention not less than 400,000, as a more preferable method, a method of performing bulk polymerization to a high conversion without using a polymerization initiator for an unsaturated monomer in a solution polymerization method. A method of performing bulk polymerization using an unsaturated carboxylic acid such as methacrylic acid as an unsaturated monomer; a method of adding a polymerization initiator and a divinyl compound after the bulk polymerization, diluting with a large amount of a solvent, and continuing the reaction; In which an unsaturated monomer is polymerized in the presence of a solvent and a divinyl compound.

Further, in order to set Mn in the present invention to 2,000 to 15,000,
Subsequent to the bulk polymerization, it can be obtained by a method in which a polymerization initiator, a solvent and, if necessary, a monomer are added in the presence of an unreacted monomer to produce a low-molecular-weight product. In addition, the above-mentioned polymer having a large Z-average molecular weight has Mn produced separately in advance of 1,500.
~ 15,000 low molecular weight compounds, each polymer dissolved in the same or mutually compatible solvent in a state of being mixed, for example, by stirring, a method of stirring each other at a temperature higher than the melting temperature, or mixing by an extruder or the like It is obtained by uniformly mixing according to the following method.

In order to increase the molecular weight of the polymer, a suspension polymerization method or an emulsion polymerization method is generally used. However,
Since the emulsifier and dispersant used at the time of polymerization are present in both the dispersion medium water and the polymer particles, it is difficult to sufficiently remove the emulsifier and dispersant, and furthermore, it is necessary to keep the removal amount of these impurities constant. Is difficult. Therefore, when used as a toner binder, it is significantly affected by environmental humidity, and it is difficult to reduce the change in the amount of charge during long-time continuous copying, which is the object of the present invention, and to always obtain a constant quality during copying. Becomes Further, even if impurities such as an emulsifier are sufficiently removed, the particle size after production is generally small and the particle size distribution is sharp. Therefore, to control the particle size and particle size distribution within the scope of the present invention, or to mix several types of resins having different particle sizes, or to pulverize a resin having a large particle size so that the particle size distribution is expanded, It is necessary to heat dissolve and cool the resin to form a resin mass and then mechanically pulverize the resin, which is not preferable because the production efficiency is low. Therefore, it is preferable to employ a solution polymerization method or a bulk polymerization method which has few of these disadvantages.

In the case of solution polymerization, benzene, toluene, ethylbenzene, orthoxylene, metaxylene, paraxylene, cumene and other aromatic hydrocarbons are used singly or in combination, but the other solvents are selected to adjust the molecular weight. It is also possible to do.

Solution polymerization is usually carried out at a reaction temperature of 80 to 150 ° C., but can be carried out outside this range in order to adjust the molecular weight. In the solution polymerization, the polymerization initiator can be generally used all that can be used as a radical polymerization initiator, for example, 2,
2'-azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,
2'-azobis (-2,4-dimethylvaleronitrile), 2,
2'-azobis (-2methylvaleronitrile), dimethyl-2,2'-azobisisobutyrate, 1,1'-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2'-azobis (2,4,4-trimethylpentane), 2-phenylazo-
2,4-dimethyl-4-methoxyvaleronitrile, 2,2'-
Azo-based initiators such as azobis (2-methyl-propane); ketone peroxides such as methyl ethyl ketone peroxide, acetylacetone peroxide and cyclohexanone peroxide; 1,1-bis (t-butylperoxy) -3,3,3; 5-trimethylcyclohexane,
1,1-bis (butylperoxy) cyclohexane, 2,2-
Peroxy ketals such as bis (t-butylperoxy) butane; hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide; 1,1,3,3-tetramethyl hydroperoxide; -Butyl peroxide, t-butylcumyl peroxide, sicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
α, α'-bis (t-butylperoxyisopropyl)
Dialkyl peroxides such as benzene, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide,
Diacyl peroxides such as 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-toluoyl peroxide, di-isopropylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-n Peroxycarbonates such as -propylperoxydicarbonate, di-2-ethoxyethylperoxycarbonate, di-methoxyisopropylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate,
Sulfonyl peroxides such as acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate,
t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy laurate,
Examples of peroxyesters such as t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyisophthalate, etc. are available. Can be selected and used as appropriate.

The toner of the present invention is mainly a powdery dry toner, and the above-mentioned polymer or polymer mixture as a main component thereof needs to be solid at room temperature, and does not fuse during pulverization. After that, it is necessary not to cause caking by leaving it for a long time. From such a viewpoint, the glass transition point of the above polymer or polymer mixture is preferably 40 ° C. or higher, more preferably 50 ° C. or higher. Further, it is preferable to soften at as low a temperature as possible from the viewpoint of low-temperature fixability.
It is preferable that the temperature is not higher than ° C.

If necessary, the binder of the present invention may be, for example, polyvinyl chloride, polyvinyl acetate, polyolefin, polyester, polyvinyl butyral, polyurethane, polyamide, rosin, modified rosin, or terpene as long as the effects of the present invention are not impaired. A resin, phenol resin, aliphatic hydrocarbon resin, aromatic petroleum resin, paraffin wax, polyolefin wax, fatty acid amide wax, or the like may be partially used.

Examples of the coloring agent used in the present invention include black pigments such as carbon black, acetylene black, lamp black, and magnetite, graphite, yellow iron oxide, Hansa Yellow G, Quinoline Yellow Lake, and Permanent Yellow NC.
G, Molybdenum Orange, Vulcan Orange, Indanthrene, Brilliant Orange GK, Bengala, Brilliant Carmine 6B, Frizarin Lake, Methyl Violet Lake, Fast Violet B, Cobalt Blue,
Known organic pigments such as alkali blue lake, phthalocyanine blue, fast sky blue, Pigment Green B, malachite green lake, titanium oxide, zinc white and the like can be mentioned. The amount is usually 5 to 250 parts by weight based on 100 parts by weight of the binder.

The toner composition of the present invention is appropriately selected and added to known charge control agents and pigment dispersants such as nigrosine, metal-containing azo dyes, quaternary ammonium salts and the like, an anti-offset agent, etc. It can be a toner.
That is, the resin mixture to which the above-mentioned various additives have been added is premixed in a powder form, then kneaded in a heated and melted state with a kneading machine such as an extruder, cooled, pulverized using a pulverizer, and further pneumatically. In general, the particles are classified by a classifier, and particles in the range of 8 to 20 μm are collected to form a toner. In addition, these specific conditions are clear from the following examples, and these conditions can be appropriately changed as necessary.

Hereinafter, the present invention will be described more specifically with reference to Examples. Units are parts by weight or% by weight unless otherwise specified.

(Measurement of GPC and THF soluble components) Measurement of Mz and Mn and THF soluble components by GPC involves crushing a resin mass, collecting those that do not pass through a 2 mm diameter sieve, and adding THF.
After adjusting the concentration to 10%, the mixture was shaken and dissolved at room temperature for 24 hours to remove insoluble components, and the removed insoluble resin was dried to obtain THF-soluble components. On the other hand, the THF-soluble matter was further diluted with THF and measured by GPC under the following conditions.

GCP device: JASCO TWINCLE HPLC DETECTOR: SHODEX RI-SE-31 COLUMNE: SHODEX GPCA-80M x 2 + KF-802 x 1 Solvent: THF Flow rate: 1.2ML / MIN Sample: 0.25% THF solution The electrophotographic copying machine EP490Z (manufactured by Minolta Camera Co., Ltd.) using a heat roll was used under the following conditions.

(Undercoat) Compared the 100th and 10,000th white background areas in continuous copy, the degree of dirt on the white background area was greatly affected by scattering, etc. ○ (good), △ (magnification of 30 times magnification) The dirt was determined by a mirror) and x (dirt could be confirmed with the naked eye).

(Change in charge amount) The triboelectric charge amount on the 100th sheet and the 10,000th sheet in continuous copying is represented by a ratio (absolute value) of the following formula, and when this ratio is 10% or less, it was judged to be good.

(Confirm the presence of unmelted resin) Place the slide glass on a hot plate at 250-300 ° C, apply a small amount of toner and melt it. At the same time, place a cover glass from above and press down at a constant pressure from above for 60 seconds. Remove from above and air-cool. After that, it was observed with a transmission optical microscope at 400 to 1,000 times, and the presence of the colorant and charge control agent was not confirmed, and the presence or absence of the resin-only part was confirmed. Is not observed, △ is suspicious, and × is the presence of only resin.

(Dispersibility of carbon black) The toner mass before coarse pulverization is sliced with a microtome, and the transmission electron microscope is used to observe carbon black uniformity and presence or absence of aggregates at a magnification of 10,000 times.
And the defect was evaluated as x. In addition, those where no agglomerates were observed were evaluated as ○, and those with many agglomerates were evaluated as x.

(Charge control agent dispersibility) The toner mass before coarse pulverization is sliced with a microtome, and the transmission control electron microscope is used to observe the uniformity of the charge control agent and the size of the dispersion at 4,000 times magnification. age,
Poor was evaluated as x. That is, when the dispersion was small and uniform in size, it was marked as ○, and when the dispersion was mixed and uneven, it was marked as x.

(D _25, the measurement of the D ₇₅₎ Tsutsui Scientific Instruments Co. desktop type standard sieve shaker VS
S-50 type is used in 6 stages, and the sieve is <JIS-Z-8801-1982).
9 mesh, 12 mesh,
The cumulative weight% is determined by the cumulative weight under the sieve at 16 mesh, 28 mesh, 60 mesh, and 150 mesh, and the horizontal axis particle size (logarithm) and the vertical axis cumulative% are plotted on a graph. % Particle size D ₂₅ and cumulative weight 75% particle size D
I read ₇₅ . However, when the resin passing through 150 mesh exceeded 25%, D ₂₅ was externally searched by connecting the data passing through 60 mesh and the data passing through 150 mesh with a straight line.

(Resin Production Example) Resin Production Example 1 60 parts of styrene and 40 parts of butyl methacrylate were charged as monomers into a nitrogen-purged flask, heated by an oil bath, the internal temperature was kept at 120 ° C., and bulk polymerization was carried out for 4 hours. I let it. When this polymerization initiator was not used, the polymerization rate of bulk polymerization was 32%. Then, 120 parts of xylene was added, and 1 part of azobisisobutyronitrile (AIBN) and 80 parts of xylene, which had been mixed and dissolved in advance, were continuously added over 10 hours while maintaining the internal temperature at 100 ° C. The polymerization was terminated by continuing the reaction for an hour. The results are shown in Table 1 with the above polymer being A.

Resin Production Example 2 A polymer was obtained in the same manner as in Resin Production Example 1 except that the polymerization time of the bulk polymerization was increased to 50% by extending the reaction time of the bulk polymerization. The results are shown in Table 1 with B being the polymer.

Resin Production Example 3 The reaction time of the bulk polymerization was shortened, and the polymerization rate of the bulk polymerization was reduced to 15
%, And in the same manner as in Production Example 1, a polymer was obtained. The results are shown in Table 1 with the polymer being C.

Resin Production Example 4 Polymer D was obtained in the same manner as in Resin Production Example 1, except that after adding 120 parts of xylene of Resin Production Example 1 and then adding 0.6 parts of divinylbenzene. The results are shown in Table 1.

Resin Production Example 5 Polymer E was obtained in the same manner as in Resin Production Example 4 except that 1.5 parts of divinylbenzene was used. The results are shown in Table 1.

Resin Production Example 6 Polymer F was prepared in the same manner as in Resin Production Example 1 except that the monomers of Resin Production Example 1 were changed to 30 parts of styrene, 30 parts of methyl methacrylate, 30 parts of butyl acrylate, and 10 parts of methacrylic acid. Obtained. The results are shown in Table 1.

Resin Production Example 7 Resin Production Example 1 except that the monomers of Resin Production Example 1 were changed to 70 parts of styrene, 28 parts of butyl acrylate, and 2 parts of methacrylic acid.
Polymer G was obtained in the same manner as described above. The results are shown in Table 1.

Resin Production Example 8 100 parts of xylene was charged into a flask, and styrene was added at 120 ° C.
A mixed solution of 90 parts, 10 parts of butyl acrylate, and 1 part of AIBN was continuously dropped over 5 hours, and thereafter polymerization was continued for 2 hours to obtain a polymer H. The results are shown in Table 1.

Resin Production Example 9 100 parts of cumene was charged into a flask, and styrene was added at 155 ° C.
A mixed solution of 90 parts, 10 parts of butyl acrylate, and 5 parts of AIBN was continuously dropped over 5 hours, and thereafter polymerization was continued for 2 hours to obtain a polymer I. The results are shown in Table 1.

Resin Production Example 10 Polymer J was obtained in the same manner as in Resin Production Example 9, except that the monomers were changed to 38 parts of styrene, 50 parts of methyl methacrylate, 10 parts of butyl acrylate, and 2 parts of methacrylic acid. The results are shown in Table 1.

(Preparation of Raw Material Resin Lumps) The polymers A to J were mixed at the resin fractions shown in Table 2, heated, desolvated under vacuum, cooled, and cooled to about 10 with a hammer.
The resultant was roughly pulverized to a size of about 20 mm to obtain resin blocks R-1 to R-9.

(Resin pulverization conditions) Pulverization condition I The resin mass was rotated using a P-3 type power mill (manufactured by Sanei Seisakusho Co., Ltd.) equipped with a round hole screen having a diameter of 4 mm at 3000 rpm.
crushed at m.

Grinding conditions II Grinding was carried out in the same manner as grinding conditions I except that the number of revolutions was changed to 2000 rpm.

Grinding condition III Grinding was carried out in the same manner as in grinding condition I except that the number of revolutions was changed to 4000 rpm.

Grinding conditions IV Grinding was carried out in the same manner as grinding conditions II except that the round hole screen was changed to 8 mm.

Grinding condition V Grinding condition II except that the round hole screen was changed to 0.35mm
Grinded in the same manner as I.

Pulverization Condition VI The resin pulverized under the pulverization condition IV was removed with a 6-mesh sieve to remove large particles of 6 mesh or more.

Pulverization condition VII The resin pulverized under the pulverization condition V was screened with a 150-mesh sieve to remove a small particle size of 150 mesh or less.

Crushing condition VIII Crushing condition V except for changing the round hole screen to 0.55mm
After pulverization was performed in the same manner as described above, a large particle size of 60 mesh or more was removed with a 60 mesh sieve, and a small particle size of 80 mesh or less was removed with a 80 mesh sieve.

Grinding Conditions IX 50 parts of the resin crushed under the crushing condition I and 50 parts of the resin crushed under the crushing condition V were mixed with a Henschel mixer.

Grinding condition X 70 parts of the resin crushed under crushing condition I and 30 parts of the resin crushed under crushing condition IV were mixed with a Henschel mixer.

Example 100 parts of adhesive and carbon black (MA-1) as a colorant
00: Mitsubishi Chemical) 10 parts, polypropylene wax 3 parts,
0.5 to 2 parts of a nigrosine dye as a charge control agent is mixed in a Henschel mixer, and a twin-screw extruder is used at 140 ° C (inlet) to 150 ° C.
After melting and kneading at a temperature of ℃ (outlet), cooling, coarse crushing, fine crushing by a jet mill, and air classification are performed to obtain a particle diameter of 8 to 20.
μm (average 11 μm) toner was produced. Thereafter, 0.15 parts of colloidal silica was added and mixed with a Henschel mixer and subjected to a test.

The amount of the charge control agent was adjusted so that the blow charge amount after mixing 5 parts of the toner with 45 parts of EP490Z carrier at 45 rpm for 30 minutes using a V blender was 14 μC / g.

Table 3 shows the test results with the above toner. From the above results, it is clear that the toner composition of the present invention exhibits extremely excellent copying characteristics.

Incidentally, the molecular weight described in the present invention, Mi per unit volume
When it is assumed that there are Ni molecules having the following molecular weights, they are respectively defined as follows.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-127070 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/08

Claims (16)

(57) [Claims] An electrophotographic toner composition comprising a binder and a colorant as main components, which are preliminarily mixed and dispersed, then kneaded, pulverized, and classified.
As a binder before dispersion, 70% by weight or more of the binder is soluble in tetrahydrofuran, the number-average molecular weight (Mn) of the tetrahydrofuran-soluble portion measured using tetrahydrofuran is 2,000 to 15,000, and the Z-average molecular weight (Mz) 400,0
Is not less than 00, and the particle diameter of D ₇₅ is 2.5 mm or less, D ₂₅ is 0.15 mm
Electrophotographic toner composition, characterized in that was adjusted to be in and D ₇₅ / D ₂₅ of 1.5 or more or more. 2. The toner composition according to claim 1, wherein Mz is 500,000 or more. 3. The toner composition according to claim 1, wherein Mz is 4,000,000 or less. 4. The toner composition according to claim 1, wherein at least 75% by weight of the binder is soluble in tetrahydrofuran. 5. The toner composition according to claim 1, wherein Mn is in the range of 2,000 to 10,000. 6. The toner composition according to claim 1, wherein D ₇₅ is 2 mm or less. 7. The toner composition according to claim 1, wherein D ₂₅ is 0.17 mm or more. 8. The toner composition according to claim 1, wherein D ₇₅ / D ₂₅ is 1.8 or more. 9. A binder comprising an acrylate resin, a methacrylate resin, a styrene resin, an acrylate ester, a styrene copolymer resin, a methacrylate ester, a styrene copolymer resin, an acrylate ester, a methacrylate ester, and a styrene copolymer. Claims 1. It is composed of one or more resins selected from the group consisting of a polymer resin, a fumarate ester, a styrene copolymer resin, a maleate ester, a styrene copolymer resin, styrene, and a butadiene copolymer resin. 3. The toner composition according to claim 1, wherein 10. A polymer of one or more monomers selected from the group consisting of aromatic vinyl monomers, acrylates, methacrylates and unsaturated carboxylic acids. 10. The toner composition according to claim 9, which is a copolymer. 11. A bulk polymerization of an unsaturated monomer without using a polymerization initiator, and then a solution polymerization of a polymerization initiator and a solvent and, if necessary, an unsaturated monomer in the presence of an unreacted monomer. 10. The toner composition according to claim 9, which is a resin obtained by the following method. 12. The toner composition according to claim 10, wherein a divinyl compound is added after the bulk polymerization. 13. A polymer having a large Mz and Mn prepared separately in advance.
The toner composition according to claim 1, wherein the toner composition is melt-mixed with a low molecular weight compound of 1,500 to 15,000 and kneaded. 14. A coloring agent of 5 to 250 parts by weight based on 100 parts by weight of the binder.
2. The toner composition according to claim 1, which is a main component consisting of parts by weight. 15. The toner composition according to claim 14, further comprising a charge adjusting agent, a pigment dispersant, and an offset preventing agent. 16. After preliminarily mixing a binder, a colorant, a charge adjusting agent, a pigment dispersant, and an offset preventing agent, the mixture is melt-kneaded by an extruder, cooled, pulverized and classified to obtain a particle diameter of 8 to 20 μm. 16. The toner composition according to claim 15, wherein: