JPH1138672A - Magnetic one-component toner matrix particles and magnetic one-component toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner giving a stable image even in an environment at high temp. and humidity and an environment at low temp. and humidity, not lowering image density and causing no fogging phenomenon by specifying the distributed state of the quantity (q/d) of electric charges of a toner before addition treatment, that is, toner matrix particles. SOLUTION: The magnetic one-component toner matrix particles contain a bonding resin, magnetic powder and an electric charge controlling agent. The distribution curve of the quantity of electric charges has at least two peaks or one peak and one shoulder on at least one of the negative and positive polarity sides. The electric charge controlling agent is a polymer of a diallyldialkylammonium salt. The polymer is contained by 0.2-5 wt.% and the magnetic powder is contained by 30-55 wt.%. The diallyldialkylammonium salt is a diallyldialkylammonium tetraphenylborate. The magnetic one-component toner matrix particles are produced by a mechanical pulverizing method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electrostatic toner used for visualizing an electrostatic image such as electrophotography.

[0002]

2. Description of the Related Art An electrophotographic process is a process in which an electrostatic latent image is formed on a photoreceptor using a photoconductive phenomenon, and toner is attached to the electrostatic latent image by electrostatic force to form a visible image. And a method of directly forming a toner image on a photosensitive paper (CPC) and a method of transferring a toner image formed on a photoconductor to recording paper (PPC). Electrophotographic developing methods include a dry developing method and a wet developing method. The main dry developing methods are a cascade developing method (U.S. Pat. No. 2,221,776) and a two-component magnetic brush developing method (U.S. Pat. No. 2,874).
063 specification), a one-component insulating toner developing method (Japanese Patent Publication No. Sho 4)
No. 1-9475) and a one-component conductive toner developing method (U.S. Pat. No. 3,909,258). Currently, the mainstream developing methods are a two-component magnetic brush developing method and a one-component insulating toner. This is a development method.

[0003] The electrophotographic developing method by the developing method includes a positive developing method in which a toner having a charge having a polarity opposite to that of a latent image is adhered, and a method in which a charge on the photosensitive member is removed from the photosensitive member. There are two types of reversal development, in which a toner charged to the same polarity as the toner is attached. The normal development method is mainly used in plain paper copying machines, but the reversal development method is used in printers and digital copying machines. For example, in a laser beam printer, a semiconductor laser (emission wavelength 76
The laser beam emitted from the light source is scanned on the surface of the photoreceptor by a polygon mirror to remove the electric charges in the image area and form an electrostatic latent image. In this method, since the light source is very small, a high resolution can be obtained, and the demand has been growing along with office automation.

The two-component magnetic brush developing method uses a mixture of toner particles and carrier particles as a developer, and transports and develops the developer by a developing roller on a magnet roller. It has the advantage that conversion is possible. However, since a mechanism for keeping the ratio of the toner and the carrier constant or a mechanism for stirring the developer is required, the apparatus becomes large and complicated, and the charging ability of the carrier is reduced due to the adhesion of the toner to the carrier surface. Therefore, if used for a long time, the carrier particles will deteriorate,
The developer needs to be replaced.

On the other hand, in the one-component insulating toner developing method, since no carrier particles are used, a mechanism for controlling and stirring the toner concentration is not required, and the apparatus can be downsized. In addition, there is an advantage that no waste such as an unnecessary carrier is generated. A typical one-component insulated toner developing method includes a BMT method using frictional charging between toners,
A jumping developing method for flying a magnetic toner frictionally charged with a sleeve or a blade is well known. Of these, the jumping development method is a non-contact development method, in which a bias voltage is applied between a gap provided between the toner layer and the photoconductor, and the electrostatic attraction force of the toner to the photoconductor and rotation of the sleeve are applied. Is a development method in which the toner flies onto the photoreceptor with the balance of the centrifugal force generated by the magnet in the sleeve and the magnetic attraction force of the sleeve, and the development is performed without contact. It can be developed at high speed. However, in the jumping development method, since there is no carrier having a large charging ability, the charging ability of the toner itself is very important. In particular, the jumping development method in a high-temperature and high-humidity environment has a disadvantage that the image density is reduced.

The toner used in the one-component developing method is obtained by dispersing a dye, a pigment, a magnetic powder and the like in a binder resin, melt-kneading with a twin-screw extruder or the like, and then pulverizing and classifying to 1 to 30 μm. in use. Dry colloidal silica or the like is used as an external additive of the toner, and greatly contributes to improvement of fluidity. It is also well known to use wet silica as an external additive in order to improve fluidity and chargeability. When the fluidity is improved, the uniformity of the toner layer on the sleeve during development is promoted, and a stable image can be obtained. However, in order to obtain a good image, it is necessary to provide a stable charge to the toner. As one of the methods, a method of adding a metal oxide such as aluminum oxide or zinc oxide serving as a charge assistant to a toner to supplement the charge is often adopted, but the effect of the charge assistant is small, especially In a high-temperature, high-humidity environment, the effect is greatly reduced. Therefore, in order to obtain a good image, the charge control agent contained in the toner is very important. As charge control agents for toners, for example, metal salt azo pigments, azo chromium complexes and the like are well known. However, the charge control agent as described above changes the charging characteristics of the toner due to changes in temperature and humidity, and causes a decrease in image density in a high-temperature and high-humidity environment in the jumping development method.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a one-component developing method, in particular, a one-component developing method using a negatively chargeable toner. And 2. To provide a toner which does not lower the image density and does not cause a fogging phenomenon.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems relating to the jumping developing method. As a result, the charge amount of the toner before external addition processing, that is, the toner base particles ( (Hereinafter also referred to as q / d) and the present invention, which has been found to be related to the image density in a high-temperature and high-humidity environment. That is, the first invention contains a binder resin, magnetic powder, and a charge control agent, and the distribution curve of the charge amount has at least two peaks on either the negative or positive polarity side, or Magnetic one-component toner base particles having two peaks and one shoulder.

A second aspect of the present invention is the magnetic one-component toner base particles according to the first aspect, wherein the charge control agent is a polymer of a diallyldialkylammonium salt.

In a third aspect of the present invention, a polymer of a diallyldialkylammonium salt is used in an amount of 0.2 to 5% by weight, and a magnetic powder is used in an amount of 30 to 50% by weight.
The magnetic one-component toner base particles according to the second invention, characterized by containing 55% by weight.

According to a fourth aspect of the present invention, there is provided a magnetic one-component toner according to the second or third aspect, wherein the polymer of the diallyldialkylammonium salt is a polymer of a tetraphenylborate salt of the diallyldialkylammonium. It is a mother particle.

According to a fifth aspect, there is provided the magnetic one-component toner base particles according to any one of the first to fourth aspects, which are produced by a mechanical pulverization method.

According to a sixth aspect, there is provided a magnetic one-component toner comprising the magnetic one-component toner base particles according to any one of the first to fifth aspects and an external additive.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for measuring a charge distribution according to the present invention will be described. The amount of triboelectric charge (q
The distribution of / d) is determined by the distance that the triboelectrically charged toner base particles fly toward the opposing (display) electrode when placed in a constant electric field and constant airflow. FIG. 1 shows an apparatus (Dr. R. H. Epping PES-L) for measuring a triboelectric charge q / d distribution of toner base particles.
(Aboratorium) and a schematic sectional view of a measuring unit. (Reference: Journal of the Society of Electrophotography, Vol. 27, No. 4, (1988)). The procedure of measuring the triboelectric charge q / d distribution of the toner base particles is as follows. In the present invention, the triboelectric charge amount (q
/ D), the toner base particle specific gravity (Spec. Density) is 1
mg / cm ³ and determined in an environment of 23 ° C. and 50% RH.

(1) The opening b of the aluminum cell 1 containing a predetermined amount (0.08 g) of the sample is set in the lower opening of the cylinder 3 for airflow, and the lower inner surface of the cylinder 3 for airflow. Is attached to the base electrode 2 and a cylinder 3 for air flow is attached.
The display electrodes 4 are mounted on the inner surface of the upper part, and these are fixed by the band 5. At this time, the distance between the base electrode 2 and the display electrode 4 is 5 cm. In addition, as a sample, this apparatus performs measurement in the following procedure. 47.5 g of an iron powder carrier having an average particle diameter of 10 μm and 2.5 g of toner base particles were weighed in a 50 cc polyethylene container and stirred and mixed with a ball mill at a speed of 100 rpm for 30 minutes to obtain a sample for measurement. I do.

(2) The magnetic brush installed under the cell 1 is rotated for a predetermined time (4 seconds) to apply a charge to the sample, and then a predetermined air flow (80 cm ³ / cm) is supplied from the opening a of the cell 1.
(Toner flow air), and while toner base particles are sent from the opening b of the cell 1 into the cylinder 3 for air flow, a predetermined amount is applied to the display electrode 4 in the case of negatively chargeable toner base particles. A voltage (+5 KV) is applied to the display electrode 4 in the case of the positively chargeable toner base particles, and a predetermined electric field (5 KV / 5 cm or −5 KV /
5cm) at a predetermined air volume (10 l / min)
The toner base particles are caused to fly for a predetermined time (10 seconds), and the charged toner base particles are electrostatically attached to the display electrode. Next, the toner base particles adhered to the display electrode are transferred and peeled off with an adhesive tape.

(3) The charge amount (q / d) of the toner base particles and its distribution are determined by analyzing the image of the toner base particles on the adhesive tape to which the toner base particles have been transferred. That is, the flying distance and the particle diameter of each toner base particle from the start point of the toner base particle on the tape are obtained, and the obtained distance and particle diameter data are used to calculate the charge amount q / d value of the toner base particle [fc / 10 μm] is required. In the formula, V [kV] is an applied voltage between the electrodes, AF [l / min] is an air flow amount, and x [mm].
Is the moving distance of the toner base particles. q / d = a × 36 × AF / (V × x) where a is the correction factor for smoll broadness of r
This is a constant called egistration elctrode. In the q / d distribution curve in the present invention, the horizontal axis of the graph is q / d (fC
/ 10 μm), the ordinate represents the amount (percentage) of the toner base particles exhibiting q / d, and the amount of the toner base particles is plotted for each 0.2 (fC / 10 μm) on the horizontal axis.

The inventors consider that the q / d distribution curve of toner base particles obtained by this measurement method has at least two peaks on the same polarity side or at least one peak and one shoulder. In addition, it has been found that the change in image density due to the environment is small. The causal relationship between the q / d distribution and the image density in a high-temperature and high-humidity environment is supposed as follows, though there are still unclear points. q /
Those having only one peak on the same polarity side in the d distribution curve are considered to have the magnetic powder and the charge control agent uniformly dispersed in the toner base particles. However, since the toner particles are uniformly dispersed, there is no difference in the charging sequence between the toner base particles, and it is difficult to charge the toner base particles due to friction between the toner base particles. For this reason, the toner containing the toner base particles is sufficiently charged by a sleeve or a blade in a normal environment, but in a high-temperature and high-humidity environment, the chargeability is reduced. Conceivable.

On the other hand, those having at least two peaks or at least one peak and one shoulder on the same polarity side in the q / d distribution curve have, in a sense, magnetic powder or charge control agent in the toner base particles. Are not uniformly dispersed. However, since the toner particles are not uniformly dispersed, they can be charged by friction between the toner base particles. It is difficult to grasp the difference between the former and the latter in the image density in a normal environment.However, in a high-temperature and high-humidity environment where charging is more difficult, improvement of the charging property due to friction between the toner base particles has a great effect. This is considered to be effective and suppress the decrease in image density.

The binder resin used in the present invention includes, for example, styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, and the like; Homopolymers and copolymers thereof; copolymers of styrene and acrylate such as styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-n-butyl acrylate copolymer Coalescence;
Styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid n
Copolymer of styrene and methacrylic ester such as butyl copolymer; multi-component copolymer of styrene and acrylate and methacrylic ester; other styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene Styrene copolymers of styrene and other vinyl monomers, such as butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile indene copolymer, styrene-maleic acid ester copolymer; Polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid, polyvinyl acetate, polyethylene,
Polypropylene, rosin, modified rosin, tempel resin,
Phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, paraffin wax, carnauba wax and the like can be used alone or in combination.

The magnetic powder used in the present invention includes, for example, iron oxides such as magnetite, γ-iron oxide, ferrite, and iron-rich ferrite; metals such as iron, cobalt and nickel; ,
Alloys with metals such as copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, calcium, manganese, titanium, tungsten, vanadium and mixtures thereof can be used, and these magnetic powders are 0.2 to 1.0 μm.
It is preferable that the toner base particles contain these magnetic components in an amount of 30 to 50% by weight. If the magnetic powder is smaller than 0.2 μm, the color tends to change from black to reddish, while if it is larger than 1.0 μm, coarse particles rapidly increase and image defects tend to occur. If the amount of the magnetic powder is less than 30% by weight, the adhesion to the sleeve is weak, so that scattering in the machine is likely to occur. On the other hand, if the amount of the magnetic powder is more than 50% by weight, the adhesion to the sleeve is too strong. Failure is likely to occur. In the present invention, if necessary, carbon black may be used together with the magnetic powder.

Examples of the charge control agent used in the present invention include a diallylalkylammonium salt polymer, a metal-containing azo dye, a metal complex or a metal salt of an alkyl salicylic acid, and a metal-containing azo dye or a metal of an alkyl salicylic acid. Since the complex or metal salt contains a metal in its skeleton, it easily absorbs moisture under high temperature and high humidity, and as a result, the resistance of the toner base particles and toner containing these metal-containing charge control agents decreases, and the chargeability decreases. Therefore, the image density tends to decrease. On the other hand, the polymer of the diallyldialkylammonium salt does not contain metals, so it is difficult to absorb moisture even in a high humidity state, and the toner base particles and the toner containing such a polymer as a charge control agent are charged by the moisture absorption even under high humidity. It is preferable to use a polymer of a diallyldialkylammonium salt as the charge control agent since the decrease hardly occurs and the image density does not easily decrease.

Examples of the counter anion of the diallyldialkylammonium salt include a halogen anion, a sulfate anion, a phosphate anion, a boron fluoride anion and a tetraphenylborate anion, and a halogen anion and a tetraphenylborate anion are preferred. Some or all of these counter anions may be replaced with other counter anions before or after polymerization.

Examples of the diallyldialkylammonium halide include diallyldialkylammonium chloride and diallyldialkylammonium bromide. Of these, diallyldialkylammonium chloride is preferred.
Diallyl diethyl ammonium chloride, diallyl methyl octyl ammonium chloride and the like.
These diallyldialkylammonium salts may be polymerized singly or may be copolymerized with an acrylic monomer. Incidentally, homopolymerization and copolymerization are collectively referred to as polymerization,
The resulting homopolymer and copolymer are collectively referred to as a polymer.

In the present invention, these diallyldialkylammonium salts may be contained in the toner base particles by adding a diallyldialkylammonium salt to a binder resin,
It is preferable to melt-knead with the magnetic powder or the like and to add internally, and it is preferable that the content is 0.2 to 5% by weight in the toner base particles. If the content is less than 0.2% by weight, the image density becomes insufficient under high temperature and high humidity. On the other hand, if the content is more than 5% by weight, no further effect is exhibited, and the cost is undesirably increased.

The toner base particles of the present invention are obtained by pulverizing by various methods after the above-mentioned melt-kneading. A so-called collision pulverization method in which the toner particles are pulverized by colliding the toner particles with a collision plate at high speed, A so-called mechanical pulverization method in which pulverization is performed by a rotating body having a gap between the rotor and the liner may be mentioned. In the case of the mechanical pulverization method, not only pulverization by collision with the rotor and the liner but also toner particles Crushed by the impact of crushing, some crushed with less energy than crushing in a collision crusher, and the temperature inside the system rises during crushing, resulting in rounded crushed shapes with sharp corners And the fluidity of the toner is improved.

In the present invention, silica fine powder,
At least one of inorganic metal fine particles such as titanium oxide, silicon oxide, aluminum oxide, and zinc oxide and organic fine particles such as polyvinylidene fluoride and polymethyl methacrylate is added to and mixed with toner base particles as an external additive. Preferably, these additives have an average particle size of 0.1
The size of the external additive is desirably about 5 μm, and may be modified by surface treatment if necessary. As the external additive, silica fine powder is particularly preferable.

The silica fine powder can be used either by a dry method or a wet method. However, in order to improve the fluidity of the toner, it is desirable to use a silica fine powder manufactured by a dry method. On the other hand, silica produced by a wet method is effective in imparting charge, and it is also preferable to use both of them. The amount of silica fine powder added is 100
The amount is preferably 0.01 to 3 parts by weight, particularly preferably 0.1 to 1.0 part by weight based on part by weight. If the amount is less than 0.01 part by weight, the fluidity tends to be insufficient. Also, 3
If it is added in excess of parts by weight, the fluidity is not further improved and the cost increases, which is not preferable. Further, it is desirable to use a silica fine powder having improved hydrophobicity and chargeability by performing a surface treatment.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which do not limit the present invention in any way. Example 1 64% by weight of a styrene-acrylic resin having a number average molecular weight of 12000 crosslinked with magnesium and having a volume average particle diameter of 0.4
33% by weight of magnetite of μm, 1% by weight of polypropylene wax having a number average molecular weight of 4000, a modified polymer of diallyldimethylammonium chloride (a homopolymer of diallyldimethylammonium chloride is dissolved in water, and sodium-tetraphenylborate is added. Was mixed using a Henschel mixer, melt-kneaded with a twin-screw extruder, pulverized with an atomizer pulverizer, which is a kind of mechanical pulverizer, and further subjected to an airflow classifier. To 12 μm to obtain toner base particles. When the q / d distribution of the obtained toner base particles was measured, it had two peaks on the negative polarity side. Next, 0.4 part by weight of dry silica fine powder was added to 100 parts by weight of the obtained toner base particles, and the mixture was dry-mixed with a Henschel mixer to obtain a magnetic one-component toner. The resulting toner was used in a commercially available one-component developing copier (trade name: NP-6060, manufactured by Canon Inc.) to perform image formation in a high-temperature, high-humidity (30 ° C., 85% RH) environment. A sufficient image density of 1.36 was obtained, and no fogging was observed. Also, 5
When a printing durability test was performed on 10,000 sheets, an image density of 1.33 equivalent to the initial level was obtained after printing 50,000 sheets, and no fogging was observed. did it. In addition, high-quality images could be stably obtained even in a low-temperature and low-humidity environment (10 ° C., 20% RH).

Example 2 48% by weight of a styrene-acrylic resin having a number average molecular weight of 7,000, 49% by weight of magnetite having a volume average particle diameter of 0.4 μm,
1% by weight of a polypropylene wax having a number average molecular weight of 4000,
2% by weight of the same modified polymer of diallyldimethylammonium chloride used in Example 1 was mixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, and then mixed with one of mechanical pulverizers. The mixture was pulverized by a KTM pulverizer and further classified to 12 μm by an airflow classifier to obtain toner base particles. When the q / d distribution of the toner mother particles was measured, it had one peak and one shoulder on the negative polarity side.

Next, 0.3 part by weight of dry silica fine powder was added to 100 parts by weight of the obtained toner base particles.
Dry mixing was performed with a Henschel mixer to obtain a magnetic one-component toner. An image was obtained by using the obtained toner in a commercial one-component developing copier (trade name: NP-6060 manufactured by Canon Inc.) in an environment of high temperature and high humidity (30 ° C., 85% RH). A sufficient image density of 1.31 was obtained, and no fogging was observed. When a 50,000-sheet printing test was performed, an image density of 1.33 equivalent to the initial level was obtained after printing 50,000 sheets, no fogging was observed, and a stable high-quality image was obtained. I got it. In addition, high-quality images could be stably obtained even in a low-temperature and low-humidity environment (10 ° C., 20% RH).

Example 3 Toner mother particles were obtained in the same manner as in Example 2 except that a polyester resin having a number average molecular weight of 3000 was used instead of the styrene-acrylic resin of Example 2. When the q / d distribution of the obtained toner base particles was measured, it had two peaks on the negative polarity side.

Next, 0.3 parts by weight of dry silica fine powder and 0.4 parts by weight of wet silica fine powder were added to 100 parts by weight of the obtained toner base particles, and a magnetic one-component toner was similarly obtained. . The obtained toner was used in a commercially available one-component developing copier (trade name: NP-8570, manufactured by Canon Inc.) to perform image formation in a high-temperature, high-humidity (30 ° C., 85% RH) environment. A sufficient image density of 1.37 was obtained, and no fogging was observed. In addition, when a 50,000-sheet printing test was performed, the same image density was obtained even after printing 50,000 sheets.
1.35 was obtained, no fogging was observed, and a high-quality image was obtained stably. In addition, high-quality images could be stably obtained even in a low-temperature and low-humidity environment (10 ° C., 20% RH).

Comparative Example 1 62% by weight of a metal-crosslinked styrene-acrylic resin having a number average molecular weight of 12000, 35% by weight of magnetite having a volume average particle diameter of 0.4 μm, 1% by weight of a polypropylene wax having a number average molecular weight of 4000, and alkyl salicylic acid 2% by weight of the chromium complex compound was mixed using a Henschel mixer,
After melt-kneading with a twin-screw extruder, the mixture was pulverized by a jet mill pulverizer and further classified to 12 μm by an airflow classifier to obtain toner base particles. When the obtained toner base particle q / d distribution was measured, it had only one peak on the negative polarity side.

Then, 0.4 parts by weight of dry silica fine powder was added to 100 parts by weight of the obtained toner base particles.
Dry mixing was performed with a Henschel mixer to obtain a magnetic one-component toner. The obtained toner is used in a commercially available one-component developing copier (trade name: NP-6060, manufactured by Canon Inc.) to stably produce high-quality images in low-temperature and low-humidity (10 ° C, 20% RH) environments. Was obtained at high temperature and high humidity (30 ° C, 85%
RH), the image density was 1.20.
And only a low image density was obtained. In addition, when a 50,000-sheet printing durability test was performed, even after printing 50,000 sheets,
The image density was as low as 1.25.

Comparative Example 2 48% by weight of styrene-acrylic resin having a number average molecular weight of 7,000, 49% by weight of magnetite having a volume average particle size of 4 m, 1% by weight of polypropylene wax having a number average molecular weight of 4000, 2% by weight of metal-containing azo dye Was mixed using a Henschel mixer, melt-kneaded with a twin-screw extruder, pulverized with an atomizer pulverizer, and further classified to 12 μm with an airflow classifier to obtain toner mother particles. When the q / d distribution of the obtained toner base particles was measured, it had only one peak on the negative polarity side.

Next, 0.4 parts by weight of dry silica fine powder was added to 100 parts by weight of the obtained toner base particles.
Dry mixing was performed with a Henschel mixer to obtain a magnetic one-component toner. The obtained toner is used in a commercial one-component developing copier (trade name: NP-6060 manufactured by Canon Inc.) to stably produce high-quality images in low-temperature and low-humidity (10 ° C, 20% RH) environments. High temperature and high humidity (30 ° C, 85% RH)
The image density was as low as 1.10 and the image density did not increase even after the printing test.

[0038]

According to the present invention, it is possible to maintain a high image density without fogging even when printing is repeatedly performed under high temperature and high humidity, as well as under low temperature and low humidity environment. .

[Brief description of the drawings]

FIG. 1: Charge amount (q / d) measuring device (schematic diagram)

Fig. 2: Schematic diagram of mechanical crusher

[Explanation of symbols]

 1: cell 2: base electrode 3: cylinder for air flow 4: display electrode 5: band 6: intake port 7: exhaust port 8: rotor 9: liner 10: electric motor

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Noboru Mogi 2-3-13-1 Kyobashi, Chuo-ku, Tokyo Inside Toyo Ink Manufacturing Co., Ltd.

Claims (6)

[Claims] Claims: 1. A binder resin, comprising a magnetic powder and a charge control agent, wherein a charge amount distribution curve has at least two peaks on one of a negative side and a positive polarity side, or one peak. Magnetic one-component toner base particles having one shoulder. 2. The magnetic one-component toner base particles according to claim 1, wherein the charge control agent is a polymer of a diallyldialkylammonium salt. 3. The magnetic one-component toner base particles according to claim 2, wherein the toner contains 0.2 to 5% by weight of a polymer of a diallyldialkylammonium salt and 30 to 50% by weight of a magnetic powder. 4. The magnetic one-component toner base particles according to claim 2, wherein the polymer of the diallyldialkylammonium salt is a polymer of a tetraphenylborate salt of the diallyldialkylammonium. 5. The magnetic one-component toner base particle according to claim 1, which is produced by a mechanical pulverization method. 6. A magnetic one-component toner comprising the magnetic one-component toner base particles according to claim 1 and an external additive.