JPH01292356A - Electrostatic charge image developing magnetic toner - Google Patents

Abstract

PURPOSE:To enhance stability of acceptance potential under an atmosphere of low humidity, independence of temperature and humidity in image quality and independence of mechanical process speed in acceptance potential by using a magnetic material having a specified compound adsorbed in the surface. CONSTITUTION:The magnetic toner to be used is composed essentially of a binder resin and the magnetic material having adsorbed the compound or a mixture of the compound represented formula I in which R is 6-24 C alkyl or alkenyl optionally substituted by hydroxyl; X is O or S; l is 0 or 1; and each of m and n is an integer of 0-30 satisfying m+n<=0-30, but the order of -(CH2CH2-O)- and -{CH(CH3)-CH2-O}- may be random. The toner contains the magnetic material in an amount of 20-150wt.%, preferably, 40-120wt.% of the resin component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner for developing electrostatic latent images in electrophotography, electrostatic recording, and the like.

[Prior Art] Conventionally, two-component toners using a carrier and one-component toners containing a magnetic component are known as dry toners used in electrophotography and the like.

- component magnetic toner has the advantage that the developing device can be simplified,
It has been widely used because it is easy to maintain.

Generally, the following method is used to produce magnetic toner.

The magnetic material, binder resin, charge control agent, etc. are mixed uniformly using a mixer such as a ball mill or Henschel mixer, and then melted and kneaded using a kneader such as a roll mill, extruder, or kneader to thoroughly incorporate each component. disperse. Thereafter, it is finely pulverized using a jet mill or the like, and then classified using an air classifier or the like to obtain a magnetic toner.

In addition, in order to improve the dispersion of the magnetic material in the binder resin,
Methods have been proposed in which the surface of a magnetic material is treated with various substances for the purpose of increasing the compatibility of the magnetic material with an organic material.

For example, JP-A-53-137148 discloses fatty acids and their derivatives, JP-A-53-81125 discloses polymeric materials, and JP-A-54-127329 discloses silane coupling agents. JP-A-55-28019 discloses a titanium coupling agent. These materials are excellent in improving compatibility.

However, in magnetic toner, a magnetic substance is exposed to some extent on the surface of the toner and discharges excessively charged charges, thereby playing a role in adjusting the amount of charge to an appropriate level. Therefore, when using a magnetic material that has been treated as described above, the surface of the magnetic material loses its philicity and polarization increases, inhibiting the release of charges, causing the toner to become overcharged, scattering on the image, and causing roughness. may occur. In addition, the reflection force on the developing sleeve becomes stronger, causing a decrease in density,
There is also a risk that the sleeve coat may become uneven. This phenomenon becomes more noticeable under low humidity conditions or in high-speed machines, and it is inevitable that image defects will occur.

On the other hand, various magnetic materials are manufactured in order to obtain desired magnetic properties, electrical properties, and powder properties, but some of them do not release sufficient charge. Also, it can withstand high temperatures, low humidity, and extremely low temperatures.

When applied to high-speed machines, there are many magnetic substances that cause image defects, although the degree is milder than in the above example.

Therefore, there is a need for a toner that can produce good images under any environment and on any model. In other words, there is a need for a magnetic toner in which a magnetic material having desired characteristics is well dispersed in a binder resin, and the amount of charge can be effectively adjusted.

[Problems to be Solved by the Invention] An object of the present invention is to provide a toner that is not affected by the environment such as temperature and humidity and provides a stable image particularly under low humidity.

Another object of the present invention is to provide a toner that is not affected by the copying speed of low-speed machines, high-speed machines, etc., and the configuration of developing devices, and provides stable images in any model.

Still another object is to provide a toner that has good dispersion of magnetic material in resin, has excellent durability, and consistently provides fog-free images even after long-term continuous use. .

Still another object is to provide a magnetic toner that does not impede the fixing properties and anti-offset properties of the binder resin.

Still another object is to provide a toner that achieves high image quality such as high resolution.

[Means for Solving the Problems] As a result of intensive research for the above purpose, the present inventors have stabilized the chargeability of toner by using a magnetic material on the surface of which a specific compound is adsorbed. The magnetic toner of the present invention is based on the above findings, and more specifically, the magnetic toner of the present invention is based on the above findings. The following general formula (
It is characterized in that the main component is a magnetic material to which a compound represented by 1) or a mixture thereof is adsorbed.

...(1) Hereinafter, the present invention will be explained in more detail. In the following description, "%" and "part" expressing quantitative ratios are based on weight unless otherwise specified.

In the magnetic toner of the present invention, a magnetic material on which a compound represented by general formula (1) is adsorbed is used.

These compounds are composed of an alkyl group serving as a hydrophobic group, an ether bond and a hydroxyl group serving as a parent group, and specifically include the compounds shown below.

C5HtrOzuH2CO2-0←-" ...(2
)(+2H2s-0-(-CH2CH2-o←--H・
...(3) Outside C+ 2H25-0-+CH2CH2-0'F----H
...(4) C+2'kh5-0-+cHzCH2-0
Masu--H...(5)? O Cl6H33-O-(-CI20Hz-0←-11-(
6) O C+aH33-0-(-CH2CH2-0←--H-(
7) C5Hu+O-((;H2C1b-0 juice, H・(8
)C9H+q+ 0 Autopsy HzCHz-Oh-H・” (
9) (C3H7)3C-0-B: H2CO2-0 juice-H
...(10)...(11) H3 CI6833-0-(-CI-CH2-0←-H...
(12) CuH25-9-+CH2GH2-0 sho--H
...(15)H3 CI6H33-S-+CH2G)! 2-0)-+cH-
CH2-Q←-)+...(16) In the above compound, the number of epoxides added is an average value, and since it is a compositional formula, the order of addition may be arbitrary.

The ether bond and hydroxyl group, which are the parent groups of the compound of the present invention, facilitate adsorption onto a magnetic material. Also,
It is thought that these functional groups suppress the polarization of the magnetic material surface and supplement effective charge release.

On the other hand, since the alkyl group exhibiting lipophilicity of the compound of the present invention spreads on the surface of the magnetic material, the compatibility with the binder resin etc. is improved,
It is believed that this improves the dispersibility of the magnetic material in the toner and also suppresses excessive moisture absorption.

This magnetic toner does not cause any significant discharge of charge, maintains good developability even under high humidity, and does not suffer from poor charging even in low-speed machines.

Many compounds are known to exhibit hydrophilic and lipophilic properties as described above, but many of them fail to release effective charge and become overcharged, or absorb moisture and release excessive charge, leading to insufficient charging. This is the result. These facts can be inferred from the relationship between the dielectric constant and frequency when the magnetic material is measured as a powder (Fig. 1).

In other words, it is thought that the dielectric properties inside the magnetic material are shown on the high frequency side, and the dielectric properties on the surface of the magnetic material are shown on the low frequency side.For example, in the case of (a) in the figure, the dielectric constant of the surface is large and the polarization is significant. At this time, it is considered that excessive charging tends to occur due to electrophotographic characteristics. - In the case of (b) and (c),
Since the dielectric constant is low and the polarization is small, charge is released due to electrophotographic characteristics, and it is considered that charging is effectively adjusted. Specifically, 1. Ordinary magnetic iron oxide left at room temperature and humidity exhibits the behavior (a), and when measured after vacuum drying, it exhibits the behavior (C). The dielectric constant increases as a result of the surface polarization increasing due to adsorption, so the dielectric constant becomes small after dry shelling. Therefore, it can be said that the surface of magnetic iron oxide is wood-philic and that charge is effectively released.

In addition, the same magnetic iron oxide treated with acid fatty metal salts, titanium carbide, and a bling agent was found to have a
), which indicates that the change in the aATff rate is small and the water desorption is small, indicating that it is hydrophobized. However, since the dielectric constant is large, the surface polarization is large and the electrophotographic characteristics tend to be excessively charged.

In fact, toner using magnetic materials that have undergone these treatments becomes overcharged when used in low humidity environments or on high-speed machines, resulting in rough images and a decrease in density.

It may also cause sleeve coat unevenness.

-The magnetic iron oxide invented by Rikiki is (
b) shows the behavior. This can be said to be hydrophobic for the same reason as above. However, in this case, the dielectric constant is small, the polarization is small, and charge is effectively emitted from the electrophotographic characteristics. In fact, the magnetic toner of the present invention gives good images even under low humidity.

As described above, the magnetic toner of the present invention exhibits stable charging properties under any environment and provides good images.

Furthermore, in high-speed machines, the supply of electric charge due to frictional electrification tends to be excessive, so the magnetic toner of the present invention is particularly preferable. It is also characterized by its excellent durability and ability to produce images with very little fog.

The amount of the compound of the present invention to be used depends on the binder resin, the magnetic material, the presence or absence of additives used as necessary, the adsorption method to the magnetic material,
The preferred usage amount is determined by the toner manufacturing method and is not uniquely limited. 0.01 to 5 parts (more preferably 0.00 parts)
1 to 3 parts). If the amount used is less than 0.01 part, the effect of charge release will not be effective, and if it is more than 5 parts, the charge will be released excessively, resulting in poor charging under high humidity and a decrease in image density. There is a fear.

The amount of the magnetic substance of the present invention contained in the toner is 20 to 150 parts, preferably 40 parts, based on 100 parts of the resin component.
~120 copies.

In order to achieve the same object as the present invention, although the effect is smaller than that of the present invention, a means of increasing the magnetic substance content may be considered. In this case, the ratio of magnetic material increases, which has a negative effect on fixing properties and causes low-temperature offset. Another disadvantage is that the organic photoreceptor is easily damaged. Furthermore, the strong magnetic binding force from the toner carrier reduces developability, resulting in image defects such as reduced image density and roughness.
It has the disadvantage of causing deterioration in image quality.

On the other hand, in the magnetic toner of the present invention, charge is effectively discharged, the amount of charge is stable, and fog is extremely low, so that the content of magnetic material can be reduced. Therefore,
The influence of magnetic binding force is reduced, resulting in improved image quality such as high density, no tailing, good resolution, and no roughness.

It is particularly advantageous in fixing properties and low-temperature offset resistance, and can fully demonstrate the performance of the binder resin. Furthermore, since it does not excessively damage the organic photosensitive layer, etc., it is preferably used in models using organic photoreceptors, etc.

The magnetic toner of the present invention exhibits its effect more effectively as the toner particle size is made smaller for the following reasons.For example, in the case of magnetic toner, when the particle size is made smaller, image defects due to increased fog and excessive charging occur. There are disadvantages such as: In order to solve these drawbacks, measures are taken to increase the magnetic material content, but this results in the above-mentioned disadvantages.
Furthermore, the smaller the toner particle size, the greater the defects, so the magnetic substance content must be increased, and the disadvantages also become greater. However, in the magnetic toner of the present invention, the magnetic substance content can be reduced, so that the adverse effects can be suppressed.The magnetic toner of the present invention has an average volume particle size of 10 #1. m
Below, the effect can be fully exhibited especially when the particle size is less than 9 mm, and it can be expected that the effect will increase as the particle size becomes smaller.

According to the findings of the present inventors, when the particle size is made smaller or the magnetic material content is reduced, the magnetic brushes on the toner carrier become shorter and denser (even if the toner coat layer becomes thinner, the developing ability decreases). The magnetic toner of the present invention achieves both of these at the same time, resulting in even better image quality. be.

In the present invention, examples of the binder resin include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichloro Styrene, p-ethylstyrene, 2,4-dimethylstyrene,
p-n-butylstyrene, p-tart-butylstyrene t P-n-hexylstyrene, p-n-octylstyrene, p-1-nonylstyrene, p-n-decylstyrene, p-n-F decylstyrene Styrene and its derivatives such as ``ethylene, propylene, butylene,
Ethylenically unsaturated monoolefins such as isobutylene;
Unsaturated polyenes such as butadiene; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl chloride; Vinyl esters such as vinyl acetate, vinyl propionate, and vinyl benzoate; Methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, inbutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, α-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-acrylate
- Acrylic acid esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether;
Vinyl chains such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl compounds such as N-vinylpyrol, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinylnaphthalenes; Acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; Vinyl compound derivatives having carboxyl groups such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid; A homopolymer containing a monomer component consisting of a vinyl compound such as half ester; maleic ms hydrate, maleic ester, fumaric ester derivative;
Copolymers: polyester, polyurethane, epoxy resin.

Polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, haloparaffin, paraffin wax, etc. can be used alone or in combination.

Among these, styrene resins, acrylic resins, and polyester resins are particularly preferably used as the binder resin in consideration of development characteristics.

In consideration of the offset resistance of the toner, the binder resin as described above is more preferably a polymer crosslinked with a crosslinking agent as exemplified below.

Aromatic divinyl compounds, such as divinylbenzene, divinylnaphthalene, etc.; diacrylate compounds linked with an alkyl chain, such as ethylene glycol diacrylate, 1,3-butylene gelicol diacrylate, 1
．． 4-butanediol diacrylate, 1.5-bentanediol diacrylate, 1.6-hexanediol diacrylate, neopentyl glycol diacrylate, and alkyl chains containing ether bonds by replacing the acrylate of the above compounds with methacrylate. diacrylate compounds linked with, for example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate,
Polyethylene glycol cloud 400 diacrylate, polyethylene glycol 5soo diacrylate, dipropylene glycol diacrylate, and 7 of the above compounds
Replacement of acrylate with methacrylate; chain-linked diacrylate compounds containing aromatic groups and ether bonds, e.g. polyoxyethylene (2)-2,2-
Bis(4-hydroxyphenyl)propane cyacrylate 1/
-, polyoxyethylene (4)-2,2-bis(4-
hydroxyphenyl) propane diacrylate, and
Examples of the above compounds in which 7 acrylates are replaced with methacrylates; furthermore, polyester type diacrylate compounds, such as the trade name MANDA (Nippon Kayaku) are listed. Examples of polyfunctional crosslinking agents include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate, and compounds in which the acrylate of the above compounds is replaced with methacrylate; Examples include allyl cyanurate and triallyl trimellitate.

These crosslinking agents are preferably used in an amount of about 0.01 to 5 parts (more preferably about 0.03 to 3 parts) per 100 parts of other monomer components.

Among these crosslinking agents, aromatic divinyl compounds (especially divinylbenzene), which are linked by chains containing aromatic groups and ether bonds, are preferably used in toner resins from the viewpoint of fixing properties and anti-offset properties. Examples include diacrylate compounds.

It is particularly desirable that at least one of these two be contained in the binder resin.

In addition, examples of binder resins for toners particularly used in pressure fixing systems include low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acids, polyamide resin, It is preferable to use polyester resin or the like alone or in combination.

The magnetic materials contained in the magnetic toner of the present invention include iron oxides such as magnetite, maghematite, and ferrite, and iron oxides including other metal oxides; metals such as Fe, Go, and metals thereof; and AP, Co.
Cu, Pb, Mg, Ni, Sn, Zn, S
b, Be.

Bi, Cd, Ca, Mn, Ss, Ti, W
, alloys with metals such as V(7), and mixtures thereof.

These ferromagnetic materials have an average particle size of about 0.1 to 2 pm, and a magnetic property with a coercive force of 20 to 1506 when 6e is applied to 10.
e Saturation magnetization 50 to 200 emu/g (preferably 50
~10100e/g), residual magnetization 2~20emu/H
Preferably.

In addition, it is preferable to use the magnetic toner of the present invention by adding a charge control agent internally or externally to the toner. - Since the magnetic toner of Rikiki's invention stabilizes charging, there is a wide range of charge control agents to choose from. be.

Known positive charge control agents can be used in the present invention, such as nigrosine and its modified products with fatty acid metal salts, quaternary ammonium salts, diorganotin oxides, diorganotin borates, etc. alone or in combination. Can be used in combination. Among these, nigrosine type and quaternary ammonium salts are particularly preferably used.

In addition, a monopolymer of a heptamer represented by the general formula or a copolymer with a polymerizable heptamer such as styrene, acrylic ester, or methacrylic ester as described above may be used as a positive charge control agent. In this case, it also functions as (part or all of) a binder resin.

On the other hand, known negative charge control agents can be used in the present invention, such as carboxylic acid derivatives and metal salts thereof,
Alkoxylates, organometallic complexes, chelate compounds, and the like can be used alone or in combination of two or more.

Among these.

Acetylacetone metal complexes, salicylic acid metal complexes, and monoazo metal complexes are particularly preferably used.

Furthermore, since the magnetic material of the present invention is positively charged to a charge imparting member such as a metal by 1 weakly, it is more preferable for positively charged toner. However, it does not adversely affect negatively charged toner.

For example, the charge amount of magnetic material B (magnetic material A (magnetic iron oxide) with 1.0% by weight of compound (3) adsorbed by the blow-off method is +15 pC/g, and magnetic material A has a charge of 114 pC/g). g
Met. This was carried out at 23.5°C and 60%RH with 0.4g of magnetic material and 1 iron powder carrier (100/200m5sh).
After accurately weighing 9.6g and mixing thoroughly, blow-off method (
This is a value measured using Toshiba Chemical Co., Ltd.'s B-200).

Generally, the presence of a portion of a toner particle that is charged with opposite polarity makes it easier to generate toner particles with reversed charge polarity, which is one of the causes of fogging on the reversed portion. Therefore, when the magnetic material B is applied to a positively charged toner, it is preferable because the fog on the reversal portion is much less than that of the magnetic material A.

However, when applied to a negatively charged toner, the fog on the reversed portion of both the magnetic material A and magnetic material 8 toners was the same.

According to the findings of the present inventors, as the amount of charge on the magnetic material increases (approximately 30.01 g or more in absolute value), there is a tendency for image defects to occur due to fogging and excessive charging of the reversal area.
This is especially noticeable when the polarity is opposite to that of the toner.
Furthermore, when the amount of charge is small, the effect is small even when the polarity is reversed, and particularly favorable results were obtained when the polarity is the same9.
Both the magnetic material and the charged material of the present invention are preferably relatively small.

In the toner of the present invention, any suitable pigment or dye can be used as a colorant, if necessary.

Furthermore, additives may be mixed into the toner of the present invention as necessary.

For example, lubricants such as Teflon, polyvinylidene fluoride, fatty acid metal salts; cerium oxide, strontium titanate,
Abrasives such as silicon carbide: colloidal silicon carbide, alumina,
Alternatively, silicone oil, various modified silicone oils, silane coupling agents, silica treated with silane coupling agents having functional groups, fluidity imparting agents such as alumina, anti-caking agents; conductors such as carbon black and tin oxide, etc. Properties imparting agent: Alternatively, there is a fixing aid such as low molecular weight polyethylene. In addition, for the purpose of improving mold release properties during hot roll fixing, waxy substances such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, and Sasol wax are used.
It is also possible to add about 0.5 to 5% by weight to the toner of the present invention.

In the present invention, as a method for adsorbing the compound used in the present invention onto a magnetic material, there are the following methods.

(1) A method in which each component of the toner is added when mixing and adsorbed to the surface of a magnetic material during mixing and crosstalk.

However, with this method, the effect may be reduced or excessive moisture absorption may occur due to penetration into the binder resin or excessive exposure of the parent wood group.

There is also a possibility that the adsorption will not be carried out effectively on the surface of the magnetic material.

Therefore, in order to efficiently adsorb the material to the magnetic material and effectively achieve the object of the present invention, it is preferable to adsorb the material to the magnetic material in advance, and the following method is available.

(2) A dry method in which the compound used in the present invention is added to a magnetic material, and then mixed and adsorbed using a Henschel mixer or a fret mill.

(3) A wet method in which the compound used in the present invention and the magnetic substance are dispersed and adsorbed in water or an organic solvent, followed by filtration and drying.

A dry method is a simple method, but a wet method is better in order to achieve more uniform adsorption on the surface of a magnetic material, and a method using water as a solvent is the best method due to safety and ease of production. This is the preferred method.

In manufacturing the toner according to the present invention, the toner constituent materials as described above are sufficiently mixed using a ball mill or other mixer, and then thoroughly kneaded using a heat kneading machine such as a hot roll, a kneader, or an extruder. A method of obtaining the toner by mechanical crushing and classification after cooling and solidification is preferred;
Another method is to obtain a toner by dispersing the constituent materials in a binder resin solution and then spray drying; or by mixing a predetermined material with the monomers that constitute the binder resin and emulsifying the Q suspension. A polymerization toner production method in which the toner is then polymerized to obtain a toner; or a method in which a predetermined material is contained in the core material, the shell material, or both in a so-called microcapsule toner consisting of a core material and a shell material; etc. This method can be applied.

The toner of the present invention can be used for one-component development for visualizing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. by any conventionally known means.

In addition, a particularly preferred developing method is to uniformly apply magnetic toner onto a cylindrical toner carrier having a magnet inside, and to develop the toner by facing the latent image holding member without contacting it. An alternating current bias may be applied between the toner carrier and the base conductor of the latent image holding member.

[Examples] The present invention will now be explained in more detail with reference to Examples, which do not limit the present invention in any way, and all parts in the following formulations are by weight. Examples of manufacturing the magnetic material used in the present invention are shown below.

Production Example 1 Magnetic substance A (magnetic iron oxide) was added to 10 volumes of an aqueous solution of compound (3) (1.0 g/i) so that the slurry concentration was 93.5 g/R, stirred for 1 hour, and then separated from the furnace. The magnetic material B was obtained by heating and drying at 120°C.

At this time, the amount of adsorption was 1.0 parts per 100 parts of the magnetic material.

Production Example 2 1.2 g/i' of compound (7) instead of compound (3)
Magnetic material C was prepared in the same manner as in Production Example 1 except that an aqueous solution of
I got it.

The adsorption amount of magnetic material C was 1.1 parts per 100 parts of magnetic material.

Production Example 3 0.8 g/j of compound (9) instead of compound (3)
A magnetic material was obtained in the same manner as in Production Example 1, except that the aqueous solution was used.

The adsorption amount of the magnetic material was 0.7 parts per 100 parts of the magnetic material.

Production Example 4 Magnetic material H was obtained in the same manner as in Production Example 1, except that magnetic material G (magnetic iron oxide) was used instead of magnetic material A.

The amount of magnetic material H adsorbed was 1.0 part per 100 parts of magnetic material.

Since the compound of the present invention is distributed into the solvent at a constant concentration, the amount of adsorption is determined by the concentration of the original solution of the compound and the concentration of the slurry of the magnetic material.

Furthermore, when fOK6e is applied to magnetic material A, the magnetic property is coercive force 13.
36 e, saturation magnetization 83.7 eiIu/g, and residual magnetization 12.5 e+su/g.

The magnetic material G has a coercive force of 636e and a saturation magnetization of 91.8, respectively.
e+su/g, and residual magnetization is 6.4 parts mu/g.

Further, other physical properties of each magnetic material are shown in Table 1.

The magnetic material used in the comparative example was manufactured as follows.

Magnetic material A was placed in a Henschel mixer, and a 5% isopropanol solution of isopropyl triisostearoyl titanate was added dropwise thereto, followed by heating and stirring at 100° C. under a nitrogen stream to obtain magnetic material E.

Magnetic material A was placed in an aqueous sodium stearate solution, and while stirring, an aqueous calcium salt solution was added dropwise to deposit and adsorb calcium stearate on the surface of the magnetic material to obtain magnetic material F.

The relative permittivity was measured by the following method.

A sample (81 substance) left in an indoor atmosphere at 20°C and 60% RH for about 12 hours was placed in a measurement cell with upper and lower electrodes (manufactured by Ando Electric, using a small-scale modified electrode surface JIi using powder electrode 5E-43.
2.27cm2, electrode load 300g), thickness 0
．． After placing this zero-order cell filled to a layer of 5 to 1.5 m into a vacuum chamber that can be evacuated to a true pressure, an impedance analyzer (manufactured by YHP,
4192A) and measure the capacitance and conductivity in the range of 4 MHz to 500 Hz, and after correcting for parasitic capacitance, calculate the apparent dielectric constant at each frequency using the thickness of the sample and the surface roughness of the electrode. and specific resistance can be derived.

The measurements were carried out under two atmospheres: 20° C. and 60% RH as described above, and the vacuum container was once evacuated to 30 Pascal or less, and then dry air with a dew point of −50° C. or lower was introduced and replaced.

(Left below) Example 1 Magnetic material B (Compound (3) i, o%) 50 parts Low molecular weight polypropylene 4 parts Nigrosine dye
2 parts The above materials were premixed in a Henschel mixer, then kneaded in an extruder heated to 150°C, cooled, coarsely pulverized in a cutter mill, pulverized in a pulverizer using a jet stream, and further pulverized in an air classifier. A fine powder with an average volume particle diameter of 114 m was obtained. 100 parts of this fine powder and 0.4 part of hydrophobic colloidal silica were thoroughly mixed to obtain a toner.

The toner obtained above is used in a reprint electronic copying machine (product name: NP).
5,540 machines, 40 copies per minute, toner replenishment type, manufactured by Canon Inc.), and a 30,000 copy repetition test was conducted.

As a result, an image faithful to the original was stably obtained during the test, and the image density was maintained at 1.30 to 1.40, with good fogging, especially fogging on the reversed portion. At this time, the thickness of the toner coat layer on the toner carrier was 130 IL.

Another 15°C! , 10% RH at low temperature and low humidity (image density 1
．． 35-1.45), 32°C, 85% RH high temperature and high humidity (image density 1.30-1.35), 30°C, 1
Under high temperature and low humidity with 0% RH (image density 1.34 to 1.42)
However, similar repeated copying test results were obtained.

During the test, the amount of charge of the toner on the toner carrier was +6 to +
It was stable within the range of 8 nc/cm2.

In addition, the above toner can be used in a commercially available electronic copying machine (product name: PC-25).
, 8 copies per minute, cartridge, disposable toner type, manufactured by Canon Inc.), and a 3000 copy test was conducted. As a result, the image density was maintained at 1.25 to 1.35, and no fogging was observed.

I continued copying, but the original image quality was maintained until the toner ran out. Further, at 15°C, 32°C under 10% RH,
Similar replication results were obtained under 90% RH.

In the present invention, the charge amount of the toner layer per unit area on the carrier was determined using the so-called suction type Faraday cage method. In this suction type Faraday cage method, the outer cylinder is pressed against the toner carrier to suck all the toner on a certain area on the carrier, and the toner is collected in a filter in the inner cylinder, and the increased weight of the filter is used to remove the toner from the toner carrier. The weight of the toner layer per unit area above can be calculated. At the same time, this method allows the amount of charge per unit area on the toner carrier to be determined by measuring the amount of charge stored in an inner cylinder that is electrostatically shielded from the outside.

Comparative Example 1 Example 1 except that 60 parts of magnetic substance A before treatment was used instead of magnetic substance B (compound (3) 1%) used in Example 1.
A toner having an average volume particle size of 11 μm was obtained in the same manner as above.

A copying test using a PC-25 machine showed the same results as in Example 1, but image deterioration was observed near the toner exhaustion. At this time, when the magnetic substance content of the toner remaining in the developing device was examined, it was found to be higher than that of the unused toner, which is considered to be caused by poor dispersion of the magnetic substance.

In a copying test using an MP-5540 machine, good images were produced, but fogging increased as the number of copies was increased.

At 15° C. and a temperature below 10%, fogging was noticeable, and fogging on the reversed portion was also noticeable.

Regarding the fixing property, there was no problem in practical use, but it was slightly inferior compared to Example 1.

During the test, the amount of charge of the toner on the toner carrier t ranged from +7 to
It was within the range of +1 lnc/c 2.

At 30°C and 1O%RH, good images were initially produced, but as the number of copies increased, roughness was observed and the image density decreased (1
, 35 → 1.15).

At this time, the amount of charge on the toner carrier was +t4nc/c@2.

Comparative Example 2 Magnetic material E (TTS
A toner having an average volume particle size of 11 was obtained in the same manner as in Example 1, except that 60 parts of 2%) were used.

In a copy test using the NP-5540 machine, good images were obtained at the beginning, but as the number of copies was increased, roughness and fog became noticeable, and the density gradually decreased (1.35 → 1.05).
I, here it comes. At this time, the amount of charge on the toner carrier was +16 nc/cm2. Furthermore, at 15° C. and 10% RH, sleeve coating unevenness occurred during the durability test and the image was distorted.

On the other hand, with the PC-25 machine, good images were obtained until the toner ran out, but roughness was observed during durability at 15° C. and 10% RH.

Comparative Example 3 A toner having an average volume particle size of 11JL11 was obtained in the same manner as in Example 1, except that 60 parts of magnetic substance F (1% Ca stearate) was used instead of magnetic substance B used in Example 1.

In the copying test using the NP-5540 machine, an image with good fogging on the white part 1 inverted part was obtained, and during the test, the amount of charge on the toner carrier was +9 to +12 nc/cm<2>.

However, when a durability test was conducted at 15° C. and 10% RH, a decrease in density was observed (from 1.40 to 1.10), and some sleeve coating unevenness occurred in the non-image area during durability. At this time, the amount of charge of the toner on the toner carrier was +15 nc/cm2.

On the other hand, with PC-25m, good images were obtained until the toner ran out (image density 1.20-1.30), but at 15°C
, the image under 10% RH was an image with a lot of scattering and roughness compared to Example 1.

Example 2 Magnetic material H (compound (3) 1%) was used instead of magnetic material B.
A fine powder having an average volume particle size of 8 μm was obtained in the same manner as in Example 1, except that 0 part was used, and 100 parts of this fine powder and 0.6 part of hydrophobic colloidal silica were thoroughly mixed to obtain a toner.

When we conducted a copying test using the NP-5540 machine, it was tested in all environments (normal temperature and humidity, 15℃, io%RH132).
℃.

85%RH) gave a good image (image density 1
．． 30-1.40).

The image obtained here was superior to the image obtained in Example 1 in terms of resolution, fine line reproducibility, and halftone dot reproducibility.

The amount of charge of the toner on the toner carrier during the test was +5 to +
It was within the range of 9 nc/cm2.

Further, in any environment, the thickness of the toner coat layer on the toner carrier was 95 μm thick.

Comparative Example 4 Magnetic material G before treatment was used instead of magnetic material H used in Example 2
The average volume particle size was 8 in the same manner as in Example 2 except that
A layer of toner was obtained.

When we conducted the same test as in Example 2, we found that the image quality was affected by density (
1.35 to 1.45) were excellent, but there was a lot of fog on the white part 1 inverted part. The charge amount of the toner on the toner carrier during this test was +7 to +1 lnc/c2, and the thickness was 100 ILs+. Also 15℃, 10%RH
In the test below, a decrease in density (from 1.30 to 1.20) was observed, especially in the non-image area during durability.

At this time, the amount of charge of the toner on the toner carrier is +14n
It was c/caw2.

Comparative Example 5 A toner having an average volume particle diameter of 81 was obtained in the same manner as in Example 2, except that 100 parts of the magnetic material G used in Comparative Example 4 was used.

When the same copying test as in Example 2 was carried out, a good image was obtained, but there was more trailing than in Example 2, the image quality and fixing performance were inferior, and the density decreased (1 ，
10 to 1.20) was observed. The amount of charge of the toner on the toner carrier during the test was within the range of +3 to +10 nc/c layer 2, and the thickness of the coating layer was 120 mm/cm.

Example 3 Magnetic substance C (Compound (7) 1.1%) 60 parts Low molecular weight polypropylene 4 parts Nigrosine dye
2 parts A toner having an average volume particle size of 1 ips was obtained in the same manner as in Example 1 except that the above materials were used.

When this toner was subjected to the same copying test as in Example 1, both the MP-5540 machine and the PC-25 machine were used in both environments (
Normal temperature and humidity, 15℃, 10%RH132℃, 85%RH
) Good images were also obtained.

NP-5540 machine Image density 1.30-1.4
0PC-25 machine Image density 1.30-1.35
The amount of charge of the toner on the toner carrier in the NP-5540 machine was within the range of +5 to +8 nc/cm2.

Example 4 Crosslinked polyester resin 100 parts Magnetic material D
(Compound (9) 0.7%) 60 parts Paper molecular weight Polypropylene 4 parts A fine powder having an average volume particle diameter of 11 pm was obtained in the same manner as in Example 1 except that the above materials were used. A toner was obtained by thoroughly mixing 100 parts of this with 0.4 parts of hydrophobic colloidal silica.

The toner obtained above was applied to a commercially available electrophotographic copying machine (product name NP-8570, 70 sheets per minute, toner replenishment type, manufactured by Canon Inc.), and a 30,000-sheet 0-return copying test was conducted. During the durability test, images faithful to the original were stably obtained and the image density was maintained at 1.32 to 1.38.

Further, at 15°C and 10% RH (image density 1.35 to 1.4
2), 32°C, 85% RH (image density 1.31-1.
34), similarly good images were obtained.

During the test, the amount of charge of the toner on the toner carrier varied from -6 to
It was stable within the range of -8 nc/cm2.

In addition, this toner can be applied to a commercially available printer (product name: LBP-
OX, 8 pages per minute, cartridge, disposable toner type, manufactured by Canon), and a 3000 printout test was conducted. As a result, the density of one image is 1.30 to 1.35
was maintained, and there was no fog. When I continued printing, the initial image quality was maintained until the toner ran out. Further, 15°C, 10% R1 (bottom, 32°C, 90% R)
Similarly good prints were obtained on the bottom.

[Effects of the Invention] Since the present invention performs the above-described magnetic material surface treatment, it exhibits the following excellent effects.

(1) Maintains stable charging even in low humidity environments.

(2) Provides stable images without being affected by temperature or humidity.

(3) Maintains stable charging regardless of the process speed of the machine, providing stable images from low-speed machines to high-speed machines.

(4) The lia material is well dispersed in the binder resin, has excellent durability, and consistently provides fog-free images.

(5) The performance of the binder resin is fully demonstrated without adversely affecting fixing properties and anti-offset properties.

(6) Achieve high image quality without fogging.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the dielectric constant and frequency of a magnetic material, and FIGS. 2 to 7 are for magnetic material A. It is a graph showing the relationship between the dielectric constant and frequency of B, E, F, G, and H. Agent Yutaka 1) Yoshio Figure 1 a Lacquer life insurance ratio t and I Tomoe Zhou lta 彎length (Hz)
High 2nd figure Ishi mazai student treatment A m Totsu length 3 figure 5) life B Shuhei 4th figure 6 room is raw Iho E Ivl'R Anjo figure 5 (64-" ↑(F (Hz) to3TO'10510'
Figure 6 tiA/1: Iho G

Claims (1)

[Claims] In a magnetic toner whose main components are a binder resin and a magnetic material,
A magnetic toner in which a compound represented by the following general formula (1) or a mixture thereof is adsorbed on the surface of the magnetic material. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (In the above general formula, R is an alkyl group or alkenyl group having 6 to 24 carbon atoms which may have a hydroxyl group as a substituent, and X is oxygen or sulfur, l is an integer of 0 or 1, m
, n represents a real number from 0 to 30 satisfying m+n≦30. However, the permutation of ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ can be random. )