JPH04237067A - Polymer toner and preparation of same - Google Patents

Abstract

PURPOSE:To obtain a toner giving a sharp image free from fog and bleeding by coating and processing the surfaces of particles obtained by suspension polymerization using a water-hardly soluble inorganic salt as a dispersion stabilizer with a silane coupling agent and specifying the electric resistivity of the particles in a state filled with tapping. CONSTITUTION:The surfaces of the particles obtained by suspension polymerization using the water-hardly soluble inorganic salt as the dispersion stabilizer are coated and processed with the silane coupling agent or a titanate coupling agent. The resistivity of the toner is regulated in a state filled with tapping to >=1.0X10<14>OMEGA.cm, thus permitting the electric charging stability of the toner to be remarkably enhanced by processing the surfaces of the polymer particles with these coupling agents, and the obtained toner to be superior in heat blocking resistance and to form a sharp image high in image density.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a toner for developing an electrostatic latent image, and particularly to a polymerized toner in which a toner is directly obtained by polymerizing a monomer composition in a dispersion medium. The present invention relates to a toner having good heat-resistant blocking properties and capable of producing high-definition images, and a method for producing the same.

0002

2. Description of the Related Art Electrophotography is known as one of various processes for forming and recording images by developing electrical or magnetic latent images. Electrophotography generally utilizes a photoconductive material to form an electrical latent image on a photoreceptor by various means, and then develops the latent image with toner to form a toner image. The obtained toner image is fixed as it is, or it is transferred to paper or the like and then fixed by heating, pressure, or other means to form a copy. Various methods have been proposed for developing with toner, such as a powder cloud method, a touchdown method, and a magnetic brush development method, and methods suitable for each image forming process are adopted.

[0003] Conventionally, toners used for these purposes are generally produced by melt-kneading a colorant consisting of a magnetic material or dye/pigment in a thermoplastic resin, uniformly dispersing the colorant in the resin, and then pulverizing and classifying the colorant. By doing so, toners with a predetermined particle size distribution have been manufactured. Additionally, various additives have been mixed as necessary to impart necessary properties to the toner. For example, a metal complex dye is added to adjust the triboelectric charging properties of the toner, and a wax or the like is added to prevent offset during heat roll fixing.

Although this method of producing toner by kneading and pulverizing can produce toner with excellent characteristics, it has certain limitations. That is, it was necessary to use a resin that is easily crushed, in other words, highly brittle. When a toner using a highly brittle resin is subjected to actual development, the stress of development causes it to become further finely powdered, making it more likely to cause deterioration called selective development or toner spent.

In addition, in this kneading-pulverization method, it is difficult to completely uniformly disperse solid particles such as colorants in the resin, and depending on the degree of dispersion, the composition of the toner may vary, causing problems in toner development. It may also cause changes in characteristics.

Furthermore, in general, the resolution, density of solid areas, and gradation reproducibility of images formed with toner largely depend on the characteristics of the toner, especially its particle size; the smaller the particle size, the higher the quality of the image. is known to be obtained. For this reason, many recent high-quality copying machines and printers use toner with small particle diameters. However, the small particle size toner produced by the kneading-pulverization method has a disadvantage of poor fluidity because the shape of the toner is more irregular. Toner with low fluidity causes problems such as bridging in the toner hopper, making it difficult to replenish the toner, or requiring a complicated device to supply the toner. Adding a large amount of fluidity modifier such as fine silica powder to improve fluidity improves fluidity, but it also causes other disadvantages such as damaging the photoreceptor and increasing fluctuations in the amount of charge due to humidity. will occur.

[0007] Therefore, in order to solve the problems of irregularly shaped toners produced by these kneading and pulverizing methods, spherical toners have been proposed.

[0008]

SUMMARY OF THE INVENTION A suspension polymerization method is known as one of the methods for producing spherical toner. In the suspension polymerization method, a monomer composition in which a polymerizable monomer, a colorant, and if necessary a polymerization initiator, a crosslinking agent, a charge control agent, and other additives are dissolved or dispersed is suspended. It is added to an aqueous phase containing a stabilizer under stirring, granulated, and polymerized to form toner particles.

[0009] This suspension polymerization method does not include any pulverization process, so the resin does not require high brittleness, and there is no exposure of coloring agent, etc. to the toner fracture surface caused by the pulverization method, so it is preferred for toner production. It is the law.

However, in this suspension polymerization method, in the step of dispersing monomers in water, gelatin,
It is necessary to stabilize the dispersion of monomer droplets by adding a water-soluble polymer such as polyvinyl alcohol, poorly water-soluble inorganic particles such as calcium phosphate, and a dispersion aid such as a surfactant. If these dispersion stabilizers remain on the particle surface after the completion of the polymerization reaction, they will inhibit the charging properties of the toner, so they are usually removed by some method. However, it is difficult to completely remove these dispersion stabilizers, and even if they are completely removed, the ionic substances used in them, such as acids and alkalis, remain on the toner surface and have an adverse effect on toner charging. This often results in fogging in the developed image.

[0011] Therefore, several methods have been known to prevent charging inhibition caused by dispersion stabilizers and to obtain good charging characteristics. For example, Japanese Patent Publication No. 1-53788 discloses a method of treating polymer particles with a silane coupling agent or a titanate coupling agent at room temperature. However, it is pointed out that a sufficient coupling reaction is not carried out in a reaction time of about 1 to 3 hours at room temperature, and the charge retention ability of the toner surface is not necessarily sufficient. When such toner is used, although no fogging occurs on the image, image deterioration during transfer, such as "dust" in fine lines and blurring in character areas, is likely to occur. Furthermore, by adding a copolymer to the monomer, we are trying to improve the heat blocking property, but adding a polymer to the monomer increases the viscosity of the monomer mixture, and even if it is dispersed while heating, it will not work. Droplets with a small particle size cannot be obtained, and therefore it is difficult to obtain polymer particles with a small particle size.

Furthermore, JP-A-1-244471 describes a method in which when polyvinyl alcohol is used as a dispersant, the resulting polymer particles are treated with alkali or acid to saponify the polyvinyl alcohol. . In this method, an increase in hydrophobicity due to saponification of polyvinyl alcohol is recognized, but since it includes a step of cleaning the toner with an alkali or acid, it is inevitable that the toner surface becomes ionic.

The object of the present invention is to make the surface of toner particles prepared in water by suspension polymerization sufficiently hydrophobic, to have a stable charge retention ability even under high temperature and high humidity, and to prevent fogging, "dust" and smearing. The purpose of the present invention is to provide a toner that provides clear images without any blemishes.

[0014]

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems. The present invention is characterized in that the particles are coated with a ring agent or a titanate coupling agent, and have an electrical resistivity of 1.0×10 14 Ω-cm or more in a tapped filling state.

[0015] Furthermore, the present invention is characterized in that a polymerizable monomer mixture containing at least an ethylenically unsaturated double bond and a coloring agent is dispersed in water using poorly water-soluble inorganic salts as a dispersion stabilizer, and then suspended. In a method for producing a polymerized toner by polymerization, after suspension polymerization, the surface of the dispersant is treated with a silane coupling agent or a titanate coupling agent at a temperature of 40° C. or higher and the softening start temperature of the toner without removing the dispersant. The coating is characterized by being heated and coated at a temperature lower than the above.

[0016] The present inventors conducted various treatments on polymer particles having the same composition, removing the dispersion stabilizer from one side and subjecting the other to silane coupling treatment, and found a large difference in the heat blocking properties of the two. We have discovered that there is, and have made the present invention. That is, the details will be described later in Examples, but for example, about 50 g of toner from which the dispersion stabilizer of polymer particles with a glass transition temperature (Tg) of 60°C has been removed/coated is placed in a cup and placed in an oven at 55°C. The results of an accelerated heat blocking test after allowing the toner to stand for 24 hours showed that the toner from which the dispersant was removed solidified into a block shape, but the toner from which the coating treatment was applied did not cause any blocking and maintained good fluidity. In addition, the glass transition temperature 5
When the same test as above was conducted on polymer particles at 0° C., the toner from which the dispersant was removed solidified, but the toner from which the coating treatment was applied did not cause any blocking and maintained good fluidity.

Based on these facts, the present inventors found that when polymer particles of the same composition were treated with the dispersion stabilizer removed on one side and subjected to silane coupling treatment on the other, there was a large difference in the heat blocking properties of the two. The present invention was developed based on the following considerations. That is, since the surface of the toner from which the dispersant has been removed is the same as the polymer constituting the toner, the tackiness of the particle surface increases due to heat, and irreversible adhesion occurs upon contact. On the other hand, a toner whose surface is treated with a coupling agent while leaving a dispersant takes the form of a type of microcapsule, in which the toners come into contact with each other through the dispersant layer, in other words, the polymers come into direct contact with each other. Therefore, it was thought that good fluidity could be maintained regardless of the glass transition temperature of the polymer.

Based on the above-mentioned knowledge, the present invention is based on the above-mentioned knowledge, and the present invention is based on the method of coating polymer particles with a silane coupling agent or the like without removing the poorly water-soluble inorganic salts as a dispersion stabilizer existing on the surface of the polymer particles after suspension polymerization. The treated particles are used as toner. As described above, the dispersion stabilizer in the prior art after polymerization is exposed on the surface and becomes a factor that inhibits the charging stability of the toner. In particular, a problem was a decrease in the amount of charge under high temperature and high humidity environments. Therefore, the dispersion stabilizer has usually been removed by washing with acid or alkali. However, this method discharges a waste liquid with a high concentration of acid or alkali and a large amount of cleaning liquid, which requires treatment of the waste liquid.

In contrast, in the present invention, by coating the dispersion stabilizer present on the surface of the polymer particles with a silane coupling agent or a titanate coupling agent,
The charging stability of the toner can be dramatically improved, and clear images without fogging can be obtained. Furthermore, the problem of waste liquid treatment can also be solved.

In the present invention, the electrical resistivity of the obtained toner in the state of tapping filling is used as an index of the surface treatment of the toner with the coupling agent, and its value is set to 1.0.
*1014 Ω-cm or more is specified, but if the electrical resistivity of the toner is less than 1.0 × 1014 Ω-cm, the electrical resistivity and charge amount will decrease in a high humidity environment, resulting in toner scattering and image fogging. This is because it is more likely to occur and is inconvenient.

[0021] Methods for measuring the electrical properties of toner include a method of melting the toner into blocks and measuring the dielectric constant and electrical resistance, and a method of measuring the electrical resistance with a constant load applied to the toner. However, in the actual development process, toner is used in a floating or weak contact state, and the measurement results in a block or compacted state and toner development characteristics did not necessarily show a good correlation. Therefore, when the electrical resistivity was measured while the toner was being tapped and filled, a good correlation with the charging stability of the toner was obtained, so this method was used in the present invention.

That is, the electrical resistivity of the toner in the present invention is determined by applying a predetermined voltage using a parallel plate electrode with a guard ring 2 as shown in FIG. 1, and after the current value becomes approximately constant. , the value of electrical resistivity was calculated from the current value. If the electrical resistance is measured while the toner is allowed to flow down naturally without being tapped and filled, there will be large variations in the measurement, and furthermore, it will cause breakdown of the device due to discharge, which is inconvenient. Tapping filling of toner is
Add toner in an amount larger than the volume applied to the electrode part of the cell,
It is preferable to tap several dozen times or more with a head difference of several millimeters to several tens of millimeters. If the number of times of tapping is small, the filling state will vary and discharge will easily occur. The gap between the electrodes is 3~
5mm is appropriate. If this gap is narrow, the filling state tends to vary and discharge is likely to occur. On the other hand, if it is wide, the current flowing through it will decrease and measurement accuracy will decrease.

[0023] The applied voltage is preferably 10,000 to 20,000 V/cm, and a low applied voltage is not preferable because the measurement current becomes small and the measurement accuracy decreases. On the other hand, if the applied voltage is too high, discharge will occur and the device will break down, which is inconvenient. In the present invention, the electrical resistivity of the toner is 10.0 at 25°C and 50% relative humidity unless otherwise specified.
The value is measured at an electric field strength of 00 V/cm.

In the present invention, it is important to coat the toner particle surface after polymerization with a coupling agent in order to make the surface of the polymer particle hydrophobic and improve the charge retention ability. As this silane coupling agent, known ones can be used. Namely, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, γ-mercaptotrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane. , vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane,
Vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, etc. can be used.

Further, as titanate coupling agents, isopropyl triisostearoyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1- Butyl) bis(di-tridecyl) phosphite titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyltrioctynor titanate, isopropyl dimethacrylylisostearoyl titanate, isopropylisostearoyl diacryl titanate, and the like can be used.

The amount of the coupling agent used in this treatment is preferably 1% by weight or more and 10% by weight or less based on the weight of all the polymer particles contained in the reaction solution. If this proportion is small, the dispersion stabilizer present on the surface of the toner cannot be sufficiently covered, resulting in a toner with poor moisture resistance. Conversely, if the proportion of coupling agent used is 10
If it is more than % by weight, the toner particles will adhere to each other and the particle size will increase, which is not preferable.

[0027] As a method of coating the toner with the coupling agent, the polymer particles may be filtered and dried and then immersed in water to which the coupling agent has been added, or the particles may be coated by spraying a solution of the coupling agent using a spray dryer. Although it is possible, it is preferable to add a coupling agent to the suspension after the completion of the polymerization reaction, perform a coating treatment, and then separate and dry the polymer particles. The relationship between the treatment conditions of the coupling agent and the physical properties of the obtained toner is important, and the degree of hydrophobicization of the surface of the polymer particles varies greatly depending on the reaction temperature of the coupling agent. Therefore, in the present invention, by setting the reaction temperature to 40° C. or higher, the electrical resistivity of the toner in a tapping-filled state is set to 1.0×10 14 Ω-cm or higher, thereby dramatically increasing the charge retention ability of the toner. It is improving. That is, for example, it is preferable to stir the mixture at a temperature of 40° C. or higher for 1 hour or more, perform a coating treatment, and then separate and dry the polymer particles. More preferably, the reaction is carried out at a temperature of 60°C or higher for 2 hours or more.

FIG. 2 is a diagram showing the relationship between toner coupling reaction time and temperature and toner electrical resistivity. At a reaction temperature lower than 40° C., sufficient coupling reaction does not proceed, and toner Electrical resistivity is 1.0×101
This is less than 4 Ω-cm, which is disadvantageous because only toner with low charging stability can be obtained. However, at a high temperature equal to or higher than the softening start temperature of the toner, toner aggregation tends to occur, so a reaction temperature of 30° C. or lower than the glass transition temperature of the toner is usually preferred.

The polymerizable monomers used in the present invention are radically polymerizable, and are used singly or in combination of two or more so that the resulting polymer has the thermal properties and electrostatic properties required for the toner. Ru. Examples of such monomers include monovinyl aromatic monomers, acrylic monomers, vinyl ester monomers, vinyl ether monomers, diolefin monomers, and monoolefin monomers. and so on.

As the monovinyl monomer, styrene, o
-Methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p-n-
Butylstyrene, p-tert-butylstyrene, p-
n-hexylstyrene, p-n-octylstyrene, p
-n-nonylstyrene, p-n-decylstyrene, p-
n-dodecylstyrene, 2,4-dimethylstyrene, 3
, 4-dichlorostyrene and its derivatives.

[0031] As the acrylic monomer, acrylic acid,
Methacrylic acid, methyl acrylate, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, methacryl Examples include dimethylaminoethyl acid and diethylaminoethyl methacrylate.

Vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl benzoate, etc.; vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether,
Examples include vinyl phenyl ether.

Examples of diolefin monomers include butadiene, isoprene, and chloroprene; examples of monoolefin monomers include ethylene, propylene, isobutylene, butene-1, pentene-1, and 4-methylpentene-1. Can be mentioned.

In the present invention, the polymerization rate and the viscosity of particles during suspension polymerization can be adjusted to produce particles having a desired particle size and particle size distribution, or to improve the offset resistance of the obtained toner. In order to improve properties, a crosslinkable monomer having two or more unsaturated bonds in one molecule may be copolymerized. Examples of the crosslinkable monomer include divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diallyl phthalate, and the like. The proportion of these crosslinkable monomers to be copolymerized with the polymerizable monomers is preferably 0.2 to 2% by weight based on the total amount of monomers. The amount of crosslinking monomer used is 0.2% by weight of the total amount of monomers.
When the amount is less than 1, coalescence of particles tends to occur during polymerization, resulting in a wide particle size distribution. Further, the offset resistance of the toner is also low. On the other hand, if the amount of the crosslinking monomer exceeds 2% by weight of the total amount of monomers, the softening temperature of the toner increases, resulting in a disadvantage that the fixing performance deteriorates.

Further, by dispersing solid fine particles such as a coloring agent in the polymerizable monomer and the crosslinkable monomer using a polyester dispersant, the dispersibility is significantly improved. As a result, the amount of colorant and polar compound exposed on the toner surface is reduced, making it possible to prevent deterioration of charging characteristics, especially in a high humidity environment, and the resulting toner scattering and fogging.

As the coloring agent, known dyes and pigments can be used. For example, the dye may include nigrosine dye, C.I. I
．． Direct Red 1, C. I. Direct Red 4, C
．． I. Acid Red 1, C. I. basic red 1
,C. I. Solvent red, C. I. bat red,
C. I. Direct Blue 1, C. I. Direct Blue 2, C. I. Acid Blue-15, C. I. Basic Blue 3, C. I. Solvent blue, C. I. Direct Green 6, C. I. There are solvent reds, etc. Examples of the pigment include furnace black, acetylene black, cadmium yellow, Hansa Yellow G, naphthol yellow S, pyrazolone red, permanent red 4R, molybdenum orange, fast violet B, phthalocyanine blue, malachite green, and phthalocyanine green. These colorants need to be contained in a proportion suitable for forming a visible image of sufficient concentration, and are usually contained in a proportion of 2 to 20% by weight based on the total amount of the monomer composition. .

When the toner is used as a magnetic toner, it is also possible to add magnetic fine particles to the monomer composition. Examples of such magnetic materials include powders of ferromagnetic metals such as iron, cobalt, and nickel, alloys of these metals with chromium, manganese, copper, zinc, aluminum, rare earth elements, etc., and their oxides, magnetite and ferrite. fine powder is used. The amount of these magnetic substances added is preferably 20 to 70% by weight based on the total weight of the toner.

As the polymerization initiator, one or a combination of two or more known polymerization initiators can be used. For example, potassium persulfate, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethyl)valeronitrile, 2,2'-azobis4-methoxy-2,
Polymerization using 4-dimethylvaleronitrile, benzoyl peroxide, 2,4-dichloroperoxide, isopropyl peroxycarbonate, cumene hydroperoxide, lauroyl peroxide, or a redox initiator. I can do it. The amount of these polymerization initiators used is preferably about 0.1 to 5% by weight of the monomer composition. In addition, in order to adjust the molecular weight of the toner produced, tert-butyl mercaptan, t
Molecular weight regulators such as ert-dodecyl mercaptan may be used simultaneously with these polymerization initiators.

When the above monomer composition is suspended in water using a mechanical or ultrasonic homogenizer and polymerized, calcium carbonate, magnesium carbonate, and phosphorus are added to stabilize the suspended state in water. It is common to use fine particles of poorly water-soluble inorganic salts such as magnesium acid, barium sulfate, silica, and alumina as a dispersion stabilizer. In particular, colloidal silica is suitable as a suspension stabilizer for toner because its primary particle size is small, ranging from 10 to 30 nm, and the desired particle size can be obtained with a smaller amount. These dispersion stabilizers are preferably used in an amount of 0.01 to 10% by weight based on the monomer. In addition to these dispersion stabilizers, there is no problem in adding a small amount of stabilizing aid. As the dispersion stabilizing agent, gelatin, carboxymethyl cellulose, starch, water-soluble polymers such as polyvinyl alcohol, surfactants, etc. can be used.

In the present invention, in addition to the above-mentioned components, additives such as a charge control agent, a fluidity modifier, a cleaning agent, and a filler may be added as necessary.

Examples of charge control agents include nigrosine, quaternized ammonium salts, polyalkylamides, molybdate chelate pigments, metal complexes of monoazo dyes, naphthenic acid metal salts, and salicylic acid metal complexes.

[0042] Fluidity modifiers include fine powders such as hydrophobic silica, titanium oxide, polyvinylidene fluoride, and metal soap, and cleaning aids include zinc stearate, calcium stearate, magnesium stearate, and the like. Fine powders of polymethyl methacrylate, nylon, polytetrafluoroethylene, silicon carbide, etc. can be used. These additives may be used by being mixed and dispersed in the monomer composition, or may be added to the surface of the obtained toner particles.

[0043]

EXAMPLES The present invention will be explained in more detail with reference to the following examples. In addition, parts in Examples and Comparative Examples represent parts by weight unless otherwise specified.

(Example 1) 70 parts of styrene, 30 parts of n-butyl methacrylate, 0.1 part of divinylbenzene, 5 parts of carbon black (#3750 manufactured by Mitsubishi Kasei), polyester dispersant (Hypermer LP5 manufactured by ICI) Part 1,
0.2 parts of a charge control agent (Eisenspiron Black TRH manufactured by Hodogaya Chemical Co., Ltd.) and 1.5 parts of polypropylene (Viscol 660 manufactured by Sanyo Chemical Co., Ltd.) were mixed and dispersed using an attritor for 6 hours.

Next, 1000 parts of ion-exchanged water aerated with nitrogen gas and 10 parts of finely powdered silica (Aerosil #300 manufactured by Nippon Aerosil) were placed in a container, and the mixture was heated using a homogenizer (
The mixture was stirred using a homomixer manufactured by Nippon Tokushu Kika Kogyo Co., Ltd., and the above monomer composition mixture containing 2 parts of azobis-2,4-dimethylvaleronitrile in a dispersion medium was added, followed by dispersion and granulation at 6000 rpm for 10 minutes. After the reaction vessel was purged with nitrogen, a stirring device equipped with a paddle stirring blade was used, and the temperature was raised to 70° C. while stirring at 200 rpm, and the reaction was carried out for 10 hours. While maintaining the temperature of the reaction system at 70°C, add the silane coupling agent γ-anilinopropyltriethoxysilane (t-
3 parts of Dow Corning Silicone SZ6083) were added and stirred for 3 hours.

The obtained polymer was filtered, washed with water, dehydrated, and dried under reduced pressure at 40° C. for 12 hours to obtain Toner 1. When the particle size of the obtained toner was measured using a Coulter counter, the volume average particle size was 6.2 μm, the number average particle size was 4.3 μm, and the number of particles of 10 μm or less was 95 μm.
% or more, no classification operation was necessary.

[0047] The electrical resistivity of the tapping filled toner state was measured using a Teflon (registered trademark) electrode with a nickel-plated brass electrode (40 mmφ) and a guard ring embedded in it, as shown in Figure 1. cell (interelectrode gap 3mm, outer dimensions 70mm width x 100mm height x 2)
0mm thickness), add toner to the top of the cell for 20 minutes.
After tapping 100 times every second with a head difference of mm, the electrical resistivity of toner 1 was 5.5 x 10.
It was 14 Ω-cm. Furthermore, when the glass transition temperature of the toner was measured using a differential scanning calorimeter (DSC), it was found to be 58.
The temperature was 5°C. This toner was placed in a cup and left in an oven at 55° C. for 24 hours, then taken out and examined for fluidity, which showed good fluidity with no change from before the test. Furthermore, almost no change was observed even after 48 hours.

A developer was prepared by mixing 4 parts of this toner and 100 parts of ferrite carrier (KBN-100, manufactured by Hitachi Metals), and when developed using a commercially available copying machine (FT4080, manufactured by Ricoh), the best image was obtained. Concentration 1.40 (O.D.)
A high-quality image with good resolution, gradation, and solid area density without brush marks or fogging was obtained. When the blow-off charge amount was measured, it was -63.2 (μC/g). Further, even in a high humidity environment of 35° C. and 80% RH, the charge amount showed a small change of -60.1 (μC/g), and a good image similar to that under a normal environment was obtained. Furthermore, there was almost no change in image quality even after copying 10,000 sheets. Further, the cleaning properties of the photoreceptor were also good, and there was no staining of the fixing roller due to offset.

(Example 2) 88 parts of styrene, 7 parts of 2-ethylhexyl acrylate, 5 parts of methyl methacrylate, 0.1 part of divinylbenzene, 5 parts of carbon black (MA-600 manufactured by Mitsubishi Chemical Industries), 1.0 part of polyester dispersant (polyhexamethylene adipate), 0.3 part of charge control agent (Bontron S-40 manufactured by Orient Chemical Co., Ltd.),
The mixture was placed in a ball mill and mixed for 8 hours.

The obtained monomer composition mixture was dispersed in water and polymerized in the same manner as in Example 1. After the polymerization, 5 parts of a silane coupling agent γ-methacryloxypropyltrimethoxysilane (SZ6030 manufactured by Toray Dow Corning Silicone) was added and stirred for 2 hours. Subsequently, filtration, washing with water, and drying were performed in the same manner as in Example 1 to obtain Toner 2. The obtained toner 2 has a volume average particle diameter of 4.6 μm.
The number average particle diameter was 3.3 μm, and no classification operation was necessary. Furthermore, the electrical resistivity of toner 2 is 2.7×101
5 Ω-cm, and the glass transition temperature was 51°C.

When this toner was used for image evaluation in the same manner as in Example 1, the image density was 1.38 (O.
D. ) A high-quality image similar to that of Example 1 was obtained with very little fogging and character dust. The blow-off charge amount is
-45.8 (μC/g). Also, 35℃80%
Charge amount -42.3 (μC/g) even under high humidity environment of RH
There was little change, and good images similar to those under normal conditions were obtained. Furthermore, there was almost no change in image quality even after copying 10,000 sheets.

Further, the melt viscosity of the toner is 1.0 at 100°C.
The fixing properties are as low as 0x105 poise, and the fixing properties are very good.
There was no stain on the fixing roller due to offset. Normally, in order to improve fixing performance from a relatively low temperature, lowering the toner's softening temperature or melt viscosity lowers the toner's glass transition temperature and deteriorates its heat blocking properties, but Toner 2 has a glass transition temperature of 51°C. 55 despite the low
There was no change in fluidity even in a heat blocking test of 24 hours at °C.

(Example 3) Styrene 80 parts, diethylamino methacrylate 15 parts, methyl methacrylate 5 parts, divinylbenzene 0.2 parts, carbon black (Cabot Sterling R) 5 parts, polyester dispersant (polytetramethylene succinate) ) and 2 parts of a charge control agent (Oil Black BY manufactured by Orient Chemical Co., Ltd.) were dispersed and mixed in a ball mill for 8 hours.

Next, 500 parts of ion-exchanged water aerated with nitrogen gas and 10 parts of finely powdered silica (Aerosil #130 manufactured by Nippon Aerosil) were placed in a container, and the mixture was stirred with a homogenizer (homogenizer manufactured by Nippon Tokushu Kika Kogyo). , the above monomer with 2 parts of lauryl peroxide added to the dispersion medium
The composition mixture was added and dispersed and granulated at 6000 rpm for 10 minutes. After the reaction vessel was purged with nitrogen, a stirring device equipped with a paddle stirring blade was used, and the temperature was raised to 70° C. while stirring at 120 rpm, and the reaction was carried out for 7 hours. Then, γ-(2
-aminoethyl)aminopropyltrimethoxysilane (
Toray Dow Corning Silicone SH6020)
Two parts were added to the reaction system and stirred at 60°C for 5 hours.

The obtained polymer was filtered, washed with water, dehydrated, and dried under reduced pressure at 40° C. for 12 hours to obtain Toner 3.
I got it. When the particle size of the obtained toner was measured using a Coulter counter, the volume average particle size was 7.5 μm, the number average particle size was 5.8 μm, and 95% or more of particles were in the range of 3 to 12 μm. , no classification operation was required. When the electrical resistivity of the toner was measured after tapping, it was 1.3×10 at an electric field strength of 10,000 V/cm.
It was 14 Ω-cm. Furthermore, when the glass transition temperature of the toner was measured using a differential scanning calorimeter (DSC), it was found to be 61°C.
Met. This toner was placed in a cup and left in an oven at 55° C. for 24 hours, then taken out and examined for fluidity, which showed good fluidity with no change from before the test.

A developer was prepared by mixing 4 parts of this toner and 100 parts of iron powder carrier (TSSV300 manufactured by Nippon Steel Powder), and when an image was created using a commercially available copying machine (SF7200 manufactured by Sharp), the best image was obtained. At a concentration of 1.45 (O.D.),
A high-quality image with good resolution, gradation, and solid area density without brush marks or fogging was obtained. The blow-off charge amount was +21.0 (μC/g). Also, 35
Even under a high humidity environment of 80% RH (° C.), a good image similar to that under a normal environment was obtained, and there was almost no change in image quality even after copying 10,000 sheets. Further, the cleaning properties of the photoreceptor were also good, and there was no staining of the fixing roller due to offset.

(Example 4) Example 4 except that 5 parts of isopropyl triisostearoyl titanate (Plenact KR-TTS manufactured by Ajinomoto Co., Ltd.) was added instead of the silane coupling agent γ-anilinopropyltriethoxysilane in Example 1. Polymer particles were produced in the same manner as in Example 1 to obtain Toner 4. The obtained toner 4 has a volume average particle diameter of 5.
The particle size was 5 μm, and the number average particle diameter was 3.6 μm, so no classification operation was necessary. Further, the electrical resistivity of toner 4 is 5.8×
1015 Ω-cm, and the glass transition temperature was 58°C.

Three parts of this toner and 97 parts of ferrite carrier (KBN-100, manufactured by Hitachi Metals, Ltd., 53-125 μm) were mixed to prepare a developer. Negatively charged phthalocyanine OP
A reversal development page printer using a C photoreceptor (
Using a developing device equipped with a 4-pole magnet roll and a non-magnetic sleeve at 800 Gauss (magnetic flux density on the sleeve), the photoreceptor surface potential was -80
0V, development gap 1mm, doctor gap 0.4m
m, 133 mm/ under development condition of development bias -400V
The image was developed at a speed of 1.5 s, transferred with a transfer voltage of +6000 V, and fixed in a fixing device equipped with a 1 kW halogen lamp and a heat roller whose surface was coated with PFA resin at a roller surface temperature of 10° C. and a linear pressure of 1 kg/cm. When evaluated, a high quality image was obtained with an average image density of 1.36 (O.D.), no brush marks or fogging, and no "dust" or smearing in the text areas.

Blow-off charge amount is -38.8 (μC/g
)Met. Further, even in a high humidity environment of 35° C. and 80% RH, there was little change in the charge amount, which was -35.2 (μC/g), and a good image similar to that under a normal environment was obtained. Another 10,0
Even after printing 00 sheets, there was almost no change in image quality, and the proportion of toner contamination on the carrier surface, so-called spent toner, was extremely low at 0.2%. Further, the cleaning properties of the photoreceptor were also good, and there was no staining of the fixing roller due to offset. Furthermore, no change was observed in the heat blocking test at 55° C. for 24 hours.

(Comparative Example 1) The silane coupling agent γ-anilinopropyltriethoxysilane of Example 1 was not added, and the polymer particles were washed with a 2N aqueous sodium hydroxide solution to remove the dispersant. After that, wash thoroughly with water, filter,
Dry. In addition, hydrophobic silica (R9 manufactured by Nippon Aerosil)
72) A toner was produced using the same composition and method as in Example 1, except that 0.5 part was added, and Toner 5 was obtained. Toner 5 had a volume average particle size of 6.0 μm and a number average particle size of 4.5 μm, and contained 95% or more of particles of 10 μm or less, so no classification operation was necessary. The electrical resistivity of the toner in the tapped state is 2.6 x 1016 Ω-cm
Met. Further, the glass transition temperature of the toner was 60°C. However, when this toner was placed in a cup and left in an oven at 55° C. for 24 hours, it was completely solidified when taken out.

When the image was evaluated in the same manner as in Example 1, the image density was 1.30 or more, but there was a lot of fog. When the blow-off charge amount was measured, it was -12.5 (μ
C/g), which was slightly low.

(Comparative Example 2) A toner was produced using the same composition and method as in Example 2, except that after the polymerization reaction, a silane coupling agent was added at room temperature and stirred at room temperature for 2 hours. Toner 6 was obtained. The particle size of the toner 6 has a volume average particle size of 5.5 μm, a number average particle size of 3.9 μm, and contains 95% or more of particles of 10 μm or less,
No classification operation was necessary. The electrical resistivity of the toner was 5.5 x 1013 Ω-cm in a normal environment, but at 35°C and 80°C.
In a high humidity environment of %RH, 4.5×1 as shown in Figure 3.
The resistance decreased to 0.012 Ω-cm.

When an image was evaluated using this toner in the same manner as in Example 2, the image density was 1.32, but a lot of toner dust was observed in characters and fine line areas. The blow-off charge amount was -57.4 (μC/g). However, under a high humidity environment of 35°C and 80%RH, the amount of charge is -
It decreased to 24.0 (μC/g), and a significant fog appeared on the image.

FIG. 3 is a diagram showing the environmental dependence of the electrical resistivity of the toners of Examples 1 to 3 and Comparative Examples 1 and 2 described above.
The electrical resistivity of Comparative Example 2, which is less than cm, is 101
It is clear that the influence of the environment is greater than that of other examples of toners having a resistance of 4 Ω-cm or more. In addition, this figure is
This figure shows the change in electrical resistivity after the toner was left in a measurement environment for about 6 hours.

(Comparative Example 3) The silane coupling agent γ-anilinopropyltriethoxysilane of Example 1 was mixed with 2N
Toner 7 was produced by using the same composition and method as in Example 1, except that the polymer particles were washed with an aqueous sodium hydroxide solution and the dispersant was added after removing the dispersant. Toner 7 has a volume average particle size of 8.2 μm and a number average particle size of 6.1
In μm, the electrical resistivity was 2.3×10 15 Ω-cm. When image evaluation was performed using a commercially available copying machine in the same manner as in Example 1, a high-quality image with no fog was obtained with an image density of 1.35. Blocking occurred. The glass transition temperature of Toner 7 was 59°C.

[0066]

[Effects of the Invention] As described above, the polymerized toner and manufacturing method of the present invention have the structure and operation as described above, and in the toner manufacturing method by dispersion polymerization, the toner has a stable charge amount and heat blocking properties. It is possible to provide a toner that has excellent image density and provides clear images without fogging. Further, according to the present invention, it is possible to provide a toner with excellent heat blocking properties that is produced in water by suspension polymerization. Furthermore, since the toner according to the present invention has excellent heat blocking properties, the softening temperature of the toner can be designed to be lower, and a toner that can be sufficiently fixed with a lower fixing temperature and lower fixing energy can be provided.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a cell for measuring electric resistivity of a tappable toner according to the present invention.

FIG. 2 is a graph showing the relationship between reaction time and electrical resistivity of a coupling agent in the present invention at various reaction temperatures.

FIG. 3 is a diagram showing the measurement results of the environmental dependence of electrical resistivity of toners of Examples of the present invention and Comparative Examples.

[Explanation of symbols]

1 Electrode 2 Guard electrode 3 Insulating holder

Claims (2)

[Claims] [Claim 1] Particles obtained by suspension polymerization using poorly water-soluble inorganic salts as a dispersion stabilizer, the surfaces of which are coated with a silane coupling agent or a titanate coupling agent, wherein the particles are in a tapping-filled state. Resistivity is 1.
A polymerized toner having a resistance of 0×10 14 Ω-cm or more. [Claim 2] A polymerizable monomer mixture containing at least an ethylenically unsaturated double bond and a colorant is dispersed in water using a poorly water-soluble inorganic salt as a dispersion stabilizer, and suspension polymerization is carried out. In a method for producing a polymerized toner, after suspension polymerization, the surface of the polymer is heated and coated with a coupling agent at a temperature of 40° C. or higher and lower than the softening start temperature of the toner without removing the dispersant. A method for producing a polymerized toner characterized by: