JPH04191864A - Magnetic toner, image forming method and device, device unit and facsimile equipment - Google Patents

Abstract

PURPOSE:To always form a uniform coating layer of a toner on a sleeve by incorporating vinyl resin contg. a THF-soluble component and resin synthesized from a conjugated diene monomer as binding resins into a resin binder and specifying the melt indexes of the binding resins. CONSTITUTION:A resin binder used is a resin mixture of 60-97 wt.% vinyl resin (A) contg. 50-80 wt.% polymer having 500-20,000 mol. wt. when the mol. wt. distribution of the THF-soluble component is measured by GPC (gel permeation chromatographyu) with 3-40 wt.% resin (B) synthesized from a conjugated diene monomer. The melt indexes (a), (b) of the binding resins A, B satisfy an equation ¦a+b¦=-0.15x+k (where x is the wt.% of the conjugated diene monomer in the monomers synthesizing the resin B and a positive number of 5-25 and k is an integer of 5-20). A uniform coating layer of a toner is formed on a sleeve over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc., and particularly relates to an insulating magnetic toner suitable for hot roll fixing and jumping development. .

In addition, the present invention develops an electrostatic charge image with magnetic toner to form a developed image, transfers the formed developed image to a recording material, and transfers the unfixed toner image on the recording material to the recording material using heat and pressure. The present invention relates to an image forming method for forming an image by fixing it.

Further, the present invention provides an electrostatic charge image carrier for carrying an electrostatic charge image, a charging means for charging the electrostatic charge image carrier, a developing means for developing the electrostatic charge image, and a developed image. The present invention relates to an image forming apparatus having a transfer means for transferring a toner image onto a recording material and a fixing means for fixing a toner image onto the recording material using heat and pressure.

Furthermore, the present invention includes an electrostatic charge image carrier for carrying an electrostatic charge image, a charging means for charging the electrostatic charge image carrier, and an L-th developing means for developing the electrostatic charge image. to form a unit, and the unit has a transfer means for transferring the developed image to the recording paper, and a fixing means for fixing the unfixed toner image to the recording paper by heat and pressure. The present invention relates to a device unit that is detachably attached to a device main body.

Furthermore, the present invention relates to a facsimile machine that uses an electrophotographic device based on the image forming apparatus described above as a printer.

BACKGROUND ART As a conventional developing method using a component magnetic toner, a developing method using a conductive magnetic toner disclosed in US Pat. No. 3,909,258 is known.

However, in such development methods, the toner must be inherently conductive, and the conductive toner is used to transfer the toner image on the latent image carrier to the final image bearing member (e.g., plain paper) using an electric field. It was difficult to transfer.

However, in JP-A-55-18656, etc.,
A new developing method has been proposed that eliminates the above-mentioned problems.

This method involves applying a very thin layer of magnetic toner onto a toner carrier (hereinafter referred to as a sleeve), triboelectrically charging it, and then developing it in close proximity to an electrostatic image.

This method increases the chances of contact between the sleeve and the toner by applying an extremely thin layer of magnetic toner onto the sleeve, enabling sufficient frictional charging, supporting the toner with magnetic force, and moving the magnet and toner relative to each other. Excellent images can be produced by moving the toner particles to prevent mutual agglomeration and creating sufficient friction with the sleeve, supporting the toner by magnetic force, and developing it by facing the electrostatic image without touching it. That's what you get.

For practical purposes, the magnetic toner used in the conventional jumping development system must maintain excellent developability even when making multiple copies and changing the environment, and stable charge control performance is required. required.

On the other hand, as a method of fixing a toner image on a recording material, an unfixed toner image is fixed by using a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer that is in pressure contact with the heating roller. A hot roll fixing method is often used, in which the held recording material is heated while being nipped and conveyed. Heat roll fixing requires a wait time for the heat roller to reach a predetermined temperature, and in order to prevent fusing failure due to the temperature of the heat roller decreasing due to the passing of the recording material or in a low-temperature environment, the heat roller Alternatively, the heat capacity of the heating element must be increased, and a large amount of electric power is required.

Therefore, in order to shorten the wait time and reduce power consumption while maintaining excellent toner visualization image fixability on recording materials, it depends largely on the characteristics of the toner, and the low-temperature fixing performance of the toner is required. It will be done.

To date, several toners have been proposed for the purpose of lowering the fixing temperature required for toner fixing.

JP-A-63-183452, JP-A-64-335
No. 58 and Japanese Unexamined Patent Publication No. 1-204061 both propose a toner containing a relatively large amount of low molecular weight polymer as a vinyl binder resin to improve the low temperature fixing of the toner. . However, with such toner,
No improvements have been made to developability, especially when a magnetic material is added to a toner containing a large amount of low molecular weight polymer as a binder resin to make a magnetic toner, and the magnetic toner is applied to the above-mentioned jumping development method. If copying is continued repeatedly, the uniformity of the toner layer carried on the sleeve will be impaired, and the thickness of the toner layer will become extremely thick in some areas compared to the initial thickness, resulting in dot-like unevenness. This has the problem of causing a splatter-like coating failure. These are observed as serpentine density unevenness when developed.

Upon further investigation, the present inventors found that as the proportion of the low molecular weight polymer in the binder resin in the magnetic toner increases, the amount of charge per unit area of the toner coated on the sleeve in the developing device increases. However, the so-called toner is charged and
I found that there is a tendency to improve. Furthermore, under low-humidity environmental conditions, if the toner is placed in a developing device and the sleeve is rotated idly, the toner coating on the sleeve may be defective due to an increase in the proportion of low molecular weight polymer in the binder resin in the magnetic toner. , which appears as a more significant phenomenon, and therefore it is considered that there is a close relationship between the proportion of the low molecular weight polymer in the binder resin and the charge controllability of the magnetic toner containing the binder resin.

In addition, Japanese Patent Publication No. 2-3178 proposes a toner containing a modified polyolefin graft-copolymerized with an aromatic hinyl monomer as a fixing aid in order to improve the low-temperature fixability while maintaining the offset resistance of the toner. has been done.

However, when a modified polyolefin, such as the modified polyolefin, which has high compatibility with the binder resin in the toner is contained in the magnetic toner, the amount of charge of the toner increases, and the defective toner coating on the sleeve becomes worse. There is a drawback that it inhibits the stabilizing function of charge control of magnetic toner.

The present inventors aimed to elucidate the reason why these magnetic toners with improved low-temperature fixing properties have unstable charge control properties.
Upon investigation, it was found that there is a difference in the degree of surface exposure of the magnetic material near the surface of the magnetic toner. For example, when observing the surfaces of various magnetic toners containing magnetic materials with an average particle size of 0.17 μm using a scanning electron microscope, it is found that magnetic toners that do not contain a low molecular weight polymer in the binder resin are shown in Figure 1. As shown in , most of the magnetic material near the toner surface has a particle structure exposed on the surface, but in magnetic toner containing a large amount of low molecular weight polymer in the binder resin, the secondary As shown in the figure, it was found that most of the magnetic material near the toner surface had a particle structure buried in the toner surface. Furthermore, in a magnetic toner that contains a large amount of low molecular weight polymer in the binder resin and further contains a graft-modified polyolefin as a fixing aid, as shown in FIG. It was confirmed that there was a tendency for the grain structure to become less exposed.

Although the exact reason why the degree of surface exposure of the magnetic material near the toner surface differs depending on the binder resin and fixing aid contained in these magnetic toners has not been elucidated, the general method for producing magnetic toners is as follows: Raw materials undergo rough mixing, kneading, pulverization, and classification processes, and if a large amount of low molecular weight content exists in the binder resin in the toner, the adhesion between the magnetic material and the resin will improve during kneading. , the magnetic material is less likely to be exposed on the toner surface during pulverization, and at the same time, the magnetic material is more likely to be embedded in the toner surface due to the impact during pulverization, and this phenomenon is further promoted by the addition of a fixing aid to the magnetic toner. It is estimated that

Therefore, in order to impart stable charge controllability to the magnetic toner, the present inventors believe that the magnetic material should be appropriately exposed on the surface of the toner, act as a leak site for excess charge, and cause the toner to charge up. It is necessary to prevent
If a large amount of low molecular weight polymer exists in the binder resin of the toner, the magnetic material near the surface will be buried, making it difficult to act as a leak site. Therefore, in magnetic toners that have improved low-temperature fixability by this method, charge control is required. It was discovered that the problem is that the properties tend to become unstable, and as a result of investigating this point, the present invention was arrived at.

[Purpose of the invention]

Therefore, it is an object of the present invention to solve the above-mentioned problems.

That is, an object of the present invention is to provide a magnetic toner that exhibits excellent low-temperature fixing performance and stable charge controllability.

A further object of the present invention is to provide a magnetic toner in which the toner coating layer on the sleeve is uniform over a long period of time even under different environmental conditions, and the band %tfi can be controlled to be suitable for the developing system used.

Another object of the present invention is to provide an image forming method that can maintain excellent toner image fixing properties on a recording material, as well as shorten wait time and reduce power consumption. .

Still another object of the present invention is to provide an image forming apparatus having a magnetic toner in its developing means, which is capable of forming an image having excellent image characteristics over a long period of time even under different environmental conditions such as low humidity and high humidity. .

Furthermore, it is an object of the present invention to include a magnetic toner in a developing means that can be detachably attached to an apparatus main body and form an image having excellent image characteristics over a long period of time even under different environmental conditions such as low humidity and high humidity. The purpose is to provide equipment units.

Still another object of the present invention is to provide a facsimile device that can output image information from a remote terminal as an image having excellent image characteristics over a long period of time even under different environments.

The magnetic toner of the present invention is a magnetic toner containing at least a binder resin and a magnetic material, in which (A) the binder resin has a molecular weight distribution of 500 to 20,000 as measured by GPC (gel permeation chromatography) of a THF-soluble component. 60 to 97% by weight of vinyl binder resin (A) containing 50 to 80% by weight of molecular weight components
and (B) 3 to 40% by weight of a binder resin (B) synthesized from at least a conjugated diene monomer, and a melt of each of the binder resin (A) and the binder resin (B). Index value (a
) and (b) are represented by the following formula % formula % (where a represents the melt index value of the binder resin of (A), b represents the melt index value of the binder resin of (B), and X represents the melt index value of the binder resin of (B)). The weight percent of the conjugated diene monomer in the monomer for synthesizing the bangu resin, which is a positive number from 5 to 25, and k is an integer from 5 to 20). It is.

In the image forming method of the present invention, an electrostatic charge image carrier carrying an electrostatic charge image on its surface and a developer carrying member holding a magnetic toner on its surface are arranged at a constant interval in a developing section. A developed image is formed by transferring magnetic toner to the electrostatic charge image carrier, and the formed developed image is transferred to a recording material with a charge of the same polarity as the electrostatic charge image, thereby forming an unfixed toner image on the transfer material. In an image forming method in which an image is formed by fixing on a recording material using heat and pressure,
60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of a molecular weight component of 0,000, and 3 to 97% by weight of a binder resin (B) synthesized from at least a conjugated/diene monomer. 40% by weight, and each of the binder resin (A) and binder resin (B) has a melt index value (
a) and (b) are represented by the following formula % formula % (wherein a represents the melt index value of the binder resin of (A), b represents the melt index value of the binder resin of (B), and X represents the melt index value of the binder resin of (B)) The weight percent of the conjugated diene monomer in the monomers used to synthesize the binder resin is a positive number from 5 to 25, and k is an integer from 5 to 20. The above object is achieved by forming an image using a magnetic toner having at least the following.

The image forming apparatus of the present invention includes an electrostatic charge image carrier for carrying an electrostatic charge image, a charging means for charging the electrostatic charge image carrier, and an electrostatic charge image carrier carried by the electrostatic charge image carrier. A developing means for developing a charge image, a transfer means for transferring the developed image developed by the developing means from the electrostatic charge image carrier to a recording material, and unfixed toner transferred to the recording material. In an image forming apparatus having a fixing means for fixing an image to a recording material by heat and pressure, the developing means holds magnetic toner on the surface thereof, which is arranged at a constant distance from the electrostatic image carrier. The magnetic toner contains at least a binder resin and a magnetic material, and the binder resin contains (A)
Molecular weight distribution measured by GPC (Kervermination chromatography) of THF soluble content: 500 to 20,0
60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of a molecular weight component of 00;
) A resin mixture containing 3 to 40% by weight of a binder resin (B) synthesized from at least a conjugated diene monomer, and each of the binder resin (A) and the binder resin (B) has a melt index value (a )as well as(
b) is the following formula 1 formula % (wherein a represents the melt index value of the binder resin of (A), b represents the melt index value of the binder resin of (B), and X represents the binder resin of (B) The above-mentioned objective is achieved by satisfying the following conditions (the percentage by weight of the conjugated diene monomer in the monomer to be synthesized is a positive number from 5 to 25, and k is a positive number from 5 to 20).

The apparatus unit of the present invention includes an electrostatic image carrier for carrying an electrostatic image, a charging means for charging the electrostatic image carrier, and an electrostatic image carried on the electrostatic image carrier. A developing means for developing the image is integrally supported to form a unit, and the unit includes a transferring means for transferring the developed image developed by the developing means from the electrostatic image carrier to the recording material. , a device unit that is removably attached to an apparatus main body and includes a fixing means for fixing an unfixed toner image transferred to the recording material to the recording material by heat and pressure, the developing means It has a developer carrier holding magnetic toner on its surface, which is disposed at a constant distance from the charge image carrier, and the magnetic toner contains at least a binder resin and a magnetic material, and the magnetic toner contains at least a binder resin and a magnetic material. The resin is (A)
Molecular weight distribution of THF soluble portion measured by GPC (gel permeation chromatography): 500 to 20.0
60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of a molecular weight component of 00;
) A resin mixture containing 3 to 40% by weight of a binder resin (B) synthesized from at least a conjugated diene monomer, and each of the binder resin (A) and the binder resin (B) has a melt index value (a )as well as(
b) is the following formula 1 formula % (wherein a represents the melt index value of the binder resin of (A), b represents the melt index value of the binder resin of (B), and X represents the binder resin of (B) The above-mentioned objective is achieved by satisfying the following formula (the percentage by weight of the conjugated diene monomer in the monomer to be synthesized is a positive number from 5 to 25, and k is an integer from 5 to 20).

The facsimile apparatus of the present invention includes an electrostatic image carrier for carrying an electrostatic image, a charging means for charging the electrostatic image carrier, and an electrostatic image carrier for carrying an electrostatic image. A charging means, a developing means for developing the electrostatic image carried on the electrostatic image carrier, and a developing means for transferring the developed image developed by the developing means from the electrostatic image carrier to a recording material. and a fixing means for fixing the unfixed toner image transferred to the recording material onto the recording material by heat and pressure; It has a developer carrier holding magnetic toner on its surface, which is disposed at a constant distance from the carrier, and the magnetic toner contains at least a binder resin and a magnetic material, and the binder resin contains a magnetic material. , (A) GPC (gel permeation chromatography) of THF soluble content
A binder resin synthesized from 60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of a molecular weight component having a molecular weight distribution of 500 to 20,000 as measured by measurement, and (B) at least a conjugated diene monomer. (B) in an amount of 3 to 40% by weight, the binder resin (A) and the binder resin (B)
Each of the melt index values (a) and (b) is expressed by the following formula 1% (where a represents the melt index value of the binder resin in (A), and b represents the melt index value of the binder resin in (B)). X is the weight percent of the conjugated diene monomer in the monomers used to synthesize the binder resin (B), and represents a positive number from 5 to 25, and k represents an integer from 5 to 20). The aim is to achieve the above objectives.

The present inventors have discovered that the binder resin contained in the magnetic toner satisfies the above conditions and has excellent low-temperature fixing performance, as well as stable charge control. It was discovered that this method does not cause coating defects.

The reason for this is not necessarily clear, but the localization of the magnetic material and the sub-binder resin (
This is thought to be due to the rubber elasticity caused by the inclusion of B).

That is, by creating a moderate difference in the melt index values of binder resins (A) and (B), and at the same time, by synthesizing binder resin (B) from a specific amount of conjugated diene monomer, the binder resin (A) is The compatibility of resin (B) can be controlled. As a result, during the kneading process of the toner manufacturing process, the binder resin (B) is appropriately micro-dispersed in the binder resin (A), and at the same time, the interface of the micro-dispersed binder resin (B) and the magnetic material are This is thought to be due to the fact that the toner mixture is more likely to be crushed from the interface of the binder resin (B) in the crushing process of the next toner manufacturing process because of the localization, making it easier for more magnetic substances to be exposed on the toner surface. .

Furthermore, if the binder resin (B) synthesized from a specific amount of conjugated diene monomer is microdispersed in the main binder resin (A), the toner itself exhibits the necessary rubber elasticity, and the impact is alleviated, making it magnetic. It is presumed that this plays a role in preventing the body from being buried in the toner surface.

As a result, although the magnetic toner of the present invention contains a large amount of low molecular weight polymer, the magnetic material contained therein is moderately exposed on the surface of the toner and effectively works against excess charge on the toner. (Therefore, there is no charge-up in the developing device, and excellent low-temperature fixing and charge controllability can be achieved at the same time.

A magnetic toner containing only the binder resin (A) used in the present invention as a binder resin has a magnetic substance embedded in the surface of the toner, and a state in which a specific amount of the binder resin (A) of the present invention is contained in the binder resin (A) of the present invention. FIGS. 2 and 4 show scanning electron micrographs of the particle structures of magnetic toners containing a resin composition to which B) is added, in which a large amount of magnetic material is exposed on the surface of the toner.

Binder resin (A) used in the magnetic toner of the present invention
is 500 to 20 in the molecular weight distribution measured by GPC (Körperminenjonk atomography) of THF-soluble components.
The weight fraction of the component having a molecular weight of 0.000 is required to be 50 to 80%, and preferably 55 to 75%. The inventors of the present invention found that even with low molecular weight components of the binder resin used in toner, the THF soluble content ranged from 500 to 20.
It has been found that the weight fraction of the molecular weight component that accounts for 0.000 contributes most effectively to low-temperature fixing, particularly in hot roll fixing.

If the weight fraction of the molecular weight component of 500 to 20,000 in the molecular weight distribution determined by GPC measurement of the THF-soluble portion of the binder resin (A) is less than 50%, the minimum fixing temperature of the toner will increase significantly, so it is preferable. On the other hand, if it exceeds 80%, the fluidity of the toner decreases, the blocking resistance of the toner in a durable developing device deteriorates, fogging is likely to occur on the image, and the stable charging of the toner deteriorates. gender is more likely to be impaired.

In addition, GP of the THF soluble portion of the binder resin (A, )
As a method of adjusting the weight fraction of the molecular weight component of 500 to 20,000 by C measurement to 50 to 80%, for example, the molecular weight distribution by GPC measurement is 5 x 103 to 1.7xlO.
It shows a maximum value in the low molecular weight region of °, and the weight average molecular weight (Mw) and number average molecular weight (Mn) are Mw/Mn≦4.
By adding and mixing an appropriate amount of a low molecular weight polymer exhibiting 0 to a high molecular weight polymer, the weight fraction can be kept within the above range.

Here, if the maximum value of the molecular weight distribution measured by GPC of the low molecular weight polymer is less than 5×10', the triboelectric charge distribution of the toner tends to be broad and non-uniform, and the resulting image after development and transfer. A fogging phenomenon occurs. On the other hand, if the maximum value of the molecular weight distribution determined by GPC measurement of the low molecular weight polymer exceeds 7 x 10', or if the value of M w / M n exceeds 4.0, the above-mentioned GPC measurement of THF soluble content is performed. It becomes difficult to keep the weight fraction of the molecular weight component within the range of 500 to 20,000.

In the present invention, the molecular weight distribution of a chromatogram by GPC (gel permeation chromatography) using THF as a solvent is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40°C, and the column at this temperature was treated with THF as a solvent.
(tetrahydrofuran) at a flow rate of 1 ml per minute,
About 100 μp of THF sample solution is injected and measured. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithm value and the count number of a calibration curve created using several types of monodisperse polystyrene standard samples.

As a standard polystyrene sample for creating a calibration curve, for example, a polystyrene sample manufactured by Tosoh Corporation or Showa Denko Corporation with a molecular weight of 102
It is appropriate to use at least 10 standard polystyrene samples with a diameter of about 10' to 10'. Also,
An RI (refractive index) detector is used as a detector. As the Naori column, it is recommended to combine a plurality of commercially available polystyrene gel columns, such as Hodex GPCKF-801, 802, 803, and 804 manufactured by Showa Denko.

A combination of 805, 806, 807, 800P, and TSKge lG100OH (H,,) manufactured by Tosoh.

G2000H (HxL'), G3000H (Hx, ).

G4000H (Hx, j　, G5000H (HxL).

G6000H (HX,), G7000H (Hx,,).

A combination of TSKguardcolumns can be mentioned.

In addition, the sample is prepared as follows.

The magnetic toner is placed in THF, left to stand for several hours, shaken thoroughly, mixed well with THF (until there is no coalescence of the sample), and left to stand for a further 12 hours or more.

At this time, the time of leaving in THF should be 24 hours or more. After that, a sample processing filter (pore size 0.45-0.5 μm, for example, Mishoridisk H-25-5 manufactured by Tosoh Corporation, Ekikurodisk 25CR manufactured by Gelman Science Japan, etc. can be used)
The sample that has passed is used as the GPC sample. Further, the sample concentration is adjusted so that the resin component is 3 to 7 mg/ml.

In addition, G of the THF soluble content of the binder resin in the present invention
The overall molecular weight distribution measured by PC means the molecular weight distribution measured with a molecular weight of 500 or more.

Binder resin (A) used in the magnetic toner of the present invention
is obtained as a polymer synthesized by adjusting the molecular weight of one or more types of heptamers selected from, for example, styrenes, acrylic acids, methacrylic acids, and derivatives thereof using a known polymerization method.

Examples of monomers that can be used include styrene, α-methylstyrene, vinyltoluene, chlorostyrene, and the like. Acrylic acids, methacrylic acids, and their derivatives include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, n-tetradecyl acrylate, and n-acrylate. Examples include acrylic esters such as hexadecyl, lauryl acrylate, cyclohexyl acrylate, diethylamine ethyl acrylate, and dimethylaminoethyl acrylate, as well as methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and methacrylic acid. Methyl, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octinomethacrylate, decyl methacrylate, dodecyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, 2-hydroquinethyl methacrylate, methacrylate Examples include methacrylic acid esters such as 2-hydroxypropyl acid, dimethylaminoethyl methacrylate, glycidyl methacrylate, and stearyl methacrylate. In addition to the monomers mentioned above, other monomers such as acrylonitrile, 2-vinylpyridine,
4-hinylpyridine, vinyl carbazole, vinyl methyl ether, maleic anhydride, maleic acid, maleic acid monoesters, maleic diesters, vinyl acetate, etc. may be used.

Further, the binder resin (A) used in the magnetic toner of the present invention may be a polymer synthesized by adding a crosslinking monomer to the momomer described above. Binder resin (Δ)
Examples of crosslinking monomers used as a bifunctional crosslinking agent include divinylhensen, bis(4-acryloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, I, 3-butylene glycol diacrylate, -butanediolne acrylate, 1,5
-Pentadiol cyacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #2
Examples include 0o, #400, and #600 diacrylates, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester diacrylate (MANDA Nippon Kayaku), and methacrylates obtained by replacing the above acrylates with methacrylates.

Pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate and its methacrylate, 2
．． Examples include 2-bis(4-methacryloxy, polyethoxyphenyl)propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl isocyanurate, triallyl trimellitate, sialyl chlorendate, and the like.

The binder resin (B), which is a sub-binder used in the magnetic toner of the present invention, needs to be a binder resin synthesized from at least a conjugated diene monomer.

The proportion of the conjugated diene monomer in the monomers for synthesizing the binder resin (B) used in the present invention is preferably 5 to 25% by weight. The proportion (X) of the conjugated diene monomer in the monomers used to synthesize the binder resin (B) is 5% by weight
If it is less than 1, the compatibility of the binder resin (B) with the binder resin (A) will improve, so the binder resin (
Microdispersion of B) becomes insufficient, and the charge controllability of the magnetic toner is impaired, and if it exceeds 25% by weight, the blocking resistance of the toner decreases.

As the conjugated diene monomer used in the binder resin (B) used in the present invention, butadiene is mainly used, but isoprene, chloroprene, etc., and derivatives thereof can also be used.

Furthermore, the binder resin used in the magnetic toner of the present invention (
Monomers other than conjugated diene monomers that can be applied to B) include styrene and substituted products thereof such as styrene, α-methylstyrene, and P-chlorostyrene; acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and acrylic Monos with double bonds such as dodecyl acid, octyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylateryl, and acrylamide. Carboxylic acids or substituted products thereof; dicarboxylic acids having double bonds such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate, etc. and substituted products thereof; for example, vinyl chloride,
Vinyl esters such as vinyl acetate, vinyl benzoate, etc. Vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, etc. Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. Two or more types of mer are used.

It is more preferable that the binder resin (B) used in the present invention is produced by polymerizing the above monomer together with a crosslinking agent.

As the crosslinking agent, compounds having two or more polymerizable double bonds are mainly used, such as aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, etc., such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, .Carboxylic acid esters having two double bonds such as 3-butanediol dimethacrylate and 1,3-butylene dimethacrylate; divinyl compounds such as cyhinyl aniline, divinyl ether, divinyl sulfide, and divinyl sulfone, and three or more vinyl Compounds having groups can be used alone or in mixtures.

The binder resin (B) used in the present invention may or may not have a THF-insoluble content.

The THF-insoluble content in the present invention refers to the weight percentage of the polymer component (substantially crosslinked polymer) that has become insoluble in THF in the resin composition, and indicates the degree of crosslinking of the resin composition containing the crosslinked component. It can be used as a parameter to indicate. The THF-insoluble content is defined by the value measured as follows.

That is, weighed 0.9 g of a resin sample (24 mesh passes, 60 mesh powder), thimble filter paper (for example, Toyo Paper No. 86R, size 28xl).
OOmm), put it in a Soxhlet extractor, extract for 6 hours using 200 ml of THF as a solvent, take out the thimble (THF outflow cycle once/4 minutes), dry it thoroughly, and weigh the THF-insoluble matter (W2. ). Resin T
The HF-insoluble content is calculated from the following formula.

W2 THF-insoluble content (%) = -xloo A vinyl binder resin (A) in which the weight fraction of molecules having a molecular weight of 500 to 20,000 as determined by GPC measurement of the THF-soluble content is 50 to 80%, and at least a conjugated diene. Binder resin (B) synthesized from monomers is preferably blended in a ratio of 70/30 to 9515.

If this ratio is less than 60/40, low-temperature fixing properties will be poor.
If it exceeds 7/3, it becomes difficult for the magnetic material to be exposed on the surface of the magnetic toner, and stable toner charge controllability is impaired.

Furthermore, the magnetic toner of the present invention includes a binder resin (A).
The absolute value of the difference between the melt index values a and b of each of satisfies the relationship shown in .

As shown in FIG. 6, the binder resin (B)
Weight% of conjugated diene monomer in the monomers used to synthesize
Absolute value of the difference between a and b of each melt index value of binder resins (A) and (B) according to (X) l a-b
By controlling l to an appropriate value, the binder resin (B) can be microdispersed in the binder resin (A). As a result, the contained magnetic material is appropriately exposed on the surface of the toner, so that stable charge control is exhibited.

Here, if k<5, regardless of the weight ratio of the conjugated diene monomer in the monomers used to synthesize the binder resin (B), the difference in melt index values between the binder resins (A) and (B) Since the absolute value 1a-bl is too small, the binder resin (B) is mixed into the binder resin (A).
The microdispersion of the magnetic toner becomes insufficient, and the charge controllability of the magnetic toner is impaired.

When k>20, the absolute value 1a-bl of the difference between the melt index values of binder resins (A) and (B) is too large, so that binder resin (B) is present in binder resin (A). Microdispersion is not achieved, resulting in non-uniform dispersion, which impairs the charge controllability of the magnetic toner.

The melt index (Ml) value referred to here is the flow test method for thermoplastic plastics JISK7 of the Japanese Industrial Standards.
Measurement was carried out using the apparatus described in No. 210 at 150° C. under a load of 2160 g and an orifice having an inner diameter of 2.0955±0.0051 mm and a length of 8.000±0.025 mm.

The magnetic toner of the present invention may contain a vinyl-based graft-modified polyolefin as a fixing aid in order to promote low-temperature fixing performance in constant fixation with a heated roller.

Since the vinyl-based graft-modified polyolefin has a modifying component with affinity in its molecular structure, it has significantly improved compatibility with the vinyl-based binder resin in magnetic toner compared to unmodified polyolefin, and has low tackiness. It is thought that the smaller the size, the greater the fluidity. As a result, the minimum fixing temperature of the magnetic toner containing the vinyl-based graft-modified polyolefin can be lowered.

However, when the vinyl-based graft-modified polyolefin is contained in a conventional magnetic toner, the magnetic material contained therein is exposed little or not at all on the toner surface, and the charge amount of the toner decreases during durability phenomena. However, as the sub-binder resin (B), a binder resin synthesized from at least a conjugated diene monomer is used. In the magnetic toner of the present invention containing the vinyl-based graft-modified polyolefin, since a large amount of magnetic material is exposed on the toner surface, even under different environments, especially under low-humidity environments, Even during long-term development, it exhibits stable charge controllability, does not charge up in the developing device, and can avoid drawbacks during development.

Examples of the polyolefin component of the vinyl graft-modified polyolefin used as a fixing aid in the semi-breakable toner of the present invention include ethylene, propylene, 1-butene,
(1) There are homopolymers of α-olefins such as -hexene and 4-methyl-1-pentene, copolymers of two or more types of α-olefins, and there are also oxides of polyolefins.

The vinyl-based graft-modified polyolefin is composed of the above-mentioned polyolefin component and a modified component, and the modified component is grafted to the polyolefin component.

As this modification component, a vinyl monomer is used,
For example, aliphatic vinyl monomers include methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl acrylate, dodecyl methacrylate, Phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroquinethyl methacrylate, 2.2.2
- Methacrylates such as trifluoroethyl methacrylate, GIJ sidyl methacrylate, acrylic acid and methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, lauryl acrylate, stearyl acrylate, todenol acrylate,
2-ethylhexyl acrylate, phenyl acrylate, 2-chloroethyl acrylate, 2-acrylic acid
and troxyethyl, cyclohexyl acrylate, dimethylaminoethyl acrylate, ethylaminoethyl acrylate, dibutylaminoethyl acrylate, 2
Ethoxy acrylate, ■, 4-butanol diacrylate, acrylates, maleic acid, fumaric acid, itaconic acid, ntraconic acid and monoethyl maleate, diethyl maleate, monopropyl maleate, dipropyl maleate, Monobutyl maleate, dibutyl maleate, C 2-functional tylhexyl maleate, monoethyl fumarate, diethyl fumarate, dibutyl fumarate, C 2
Ethylhexyl fumarate, monoethyl itaconate,
Examples include diethyl itaconate, monoethyl traconate, and ethyl citraconate, and one or more of these can be used simultaneously.

Further, aromatic vinyl monomers include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene,
α-methylstyrene, 2,4-methylstyrene, p-
Ethylstyrene, p-n-butylstyrene, p-ter
t-butylstyrene, p-n-dodecylstyrene, p-
Examples include phenylstyrene and p-chlorostyrene, and one or more of these can be used simultaneously.

As a method for graft modification, conventionally known methods can be used. For example, a graft-modified polyolefin can be obtained by heating and reacting the polyolefin with an aromatic vinyl monomer and an aliphatic vinyl monomer in a molten state or a molten state in the atmosphere or under pressure in the presence of a Rancal initiator. Grafting with an aromatic vinyl monomer and an aliphatic vinyl monomer may be carried out simultaneously or individually.

The content of the grafting agent in the polyolefin is preferably from 0.1 to 90 parts by weight, more preferably from 2 to 50 parts by weight, per 100 parts by weight of the polyolefin. If it is less than 1 part by weight, the compatibility with the binder resin in the toner will deteriorate, while if it exceeds 90 parts by weight, the compatibility will improve, but the ratio of the polyolefin component will decrease, so in either case, the toner will not be compatible with the binder resin. The effect of low-temperature fixing is reduced.

The amount of the graft-modified polyolefin used in the present invention is 081 to 2 parts by weight per 100 parts by weight of the binder resin.
It is preferably 0 parts by weight, more preferably 0.5 to 10 parts by weight. When the amount is less than 0.1 parts by weight, the effect on low-temperature fixing may not be exhibited, and when it is more than 20 parts by weight, the blocking properties of the toner tend to deteriorate.

In the magnetic toner of the present invention, it is preferable to use a charge control agent by blending it into the toner particles (internally adding it) or mixing it with the toner particles (externally adding it). The charge control agent makes it possible to optimally control the amount of charge depending on the developing system, and in particular, in the present invention, it is possible to further stabilize the balance between particle size distribution and charge. Examples of positive charge control agents include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroporate; dibutyltin oxide and dioctyltin. oxide, diorganotin oxide such as dicyclohexyltin oxide: dibutyltin porate, dioctyltin porate,
Diorgano tin porate such as dicyclohexyl tin porate can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

General formula [wherein R1 represents H or CH, R2 and R1
is a substituted or unsubstituted alkyl group (preferably (ma, 01
~C,) is shown. ] A homopolymer of a monomer represented by; a copolymer with a polymerizable monomer such as styrene, acrylic ester, or methacrylic ester as described above is used as a positive charge control agent) In this case, these charge control agents also act as (in whole or in part) a binder resin.

As the negative chargeability control UL that can be used in the present invention, for example, organic metal complexes and chelate compounds are very effective. Examples thereof include aluminum acetyfuracetonate, iron (n) acetylacetonate, and Chromium butyl salicylate is also commonly used. Particularly preferred are acetylacetone metal complexes, IJ tylic acid-based metal complexes (including monoalkyl-substituted or dialkyl-substituted products), or salicylic acid-based metal salts (including monoalkyl-substituted and dialkyl-substituted products).

The above-mentioned charge control agent (one that does not function as a binder resin) is preferably used in the form of fine particles. In this case, the number average particle size of this charge control agent is specifically:
The thickness is preferably 4 μm or less (more preferably 3 μm or less).

When internally added to the toner, such a charge control agent is preferably used in an amount of 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) per 100 parts by weight of the binder resin.

Various additives may be added internally or externally to the magnetic toner according to the present invention, if necessary. As the colorant, conventionally known dyes and pigments can be used, and usually 0.5 to 20 parts by weight may be used per 100 parts by weight of the binder resin. Other additives include, for example, lubricants such as zinc stearate; abrasives such as cerium oxide, silicon carbide; flow agents or anti-caking agents such as colloidal silica, aluminum oxide; carbon black, tin oxide, etc. There are conductivity imparting agents.

Low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, Sasol wax,
It is also a preferred embodiment of the present invention to add a waxy substance such as paraffin wax to the magnetic toner in an amount of about 0.5 to 5% by weight based on the binder resin.

Furthermore, the magnetic toner according to the present invention contains a magnetic material. The magnetic materials contained in the magnetic toner of the present invention include iron oxides such as magnetite, γ-iron oxide, ferrite, and iron-rich ferrite.

Metals such as iron, cobalt, nickel or these metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium Examples include alloys with other metals and mixtures thereof.

These ferromagnetic materials preferably have an average particle size of about 0.1 to 1 μm, preferably about 0.1 to 0.5 μm. The amount to be contained in the magnetic toner is 60 to 120 parts by weight per 100 parts by weight of the resin component, preferably 1 part by weight of the resin component.
00 parts by weight, the amount is 65 to 110 parts by weight.

To prepare the magnetic toner according to the present invention, a magnetic material and a vinyl thermoplastic resin, a resin synthesized from a conjugated dinin monomer, a fixing aid, a pigment or dye as a coloring agent if necessary, a charge control agent, Other additives are thoroughly mixed using a mixer such as a ball mill, and then heated using rolls and a kneader.
The present invention is produced by dispersing or dissolving pigments or dyes in a mixture of resins that is made compatible with each other by melting, kneading, and kneading using a hot kneader such as an extruder, and then pulverizing and classifying after cooling and solidifying. It is possible to obtain a magnetic toner according to the above.

Fine silica powder may be added internally or externally to the magnetic toner according to the present invention, but it is more preferable to mix it externally. When magnetic toner particles are brought into contact with the surface of a cylindrical conductive sleeve that has a magnetic field generating means inside for frictional charging, the number of times the toner particle surface contacts the sleeve increases, causing wear of the toner particles. It becomes easier. When the magnetic toner according to the present invention is combined with fine silica powder, wear is significantly reduced due to the presence of the fine silica powder between the toner particles and the sleeve surface. As a result, the life of the magnetic toner can be extended, and it is possible to obtain a developer having magnetic toner that is more excellent for long-term use.

As the silica fine powder, both silica fine powder produced by a dry method and a wet method can be used, but from the viewpoint of filming resistance and durability, it is preferable to use a silica fine powder produced by a dry method.

The dry method mentioned here is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halide compound. For example, this method utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.

S i Cl, + 2 H, +O□→S i O2+4
HC (! For example, by using other metal halogen compounds such as aluminum chloride or titanium chloride together with silicon halogen compounds in this manufacturing process, it is also possible to obtain composite fine powders of silica and other metal oxides, and they are also include.

Commercially available fine silica powder produced by vapor phase oxidation of a silicon halogen compound used in the present invention includes, for example, those commercially available under the following trade names.

AERO3IL 130 (Japan Aerosil Co., Ltd.) 200X50 T600 0X80 0X170 0K84 Ca-0-8iL M-5 (CAB
OTOCo, Inc.) MS-7 S-5 H-5 Wacker HDK N 20 V
15 (WACKER-CHEMIE GMBH) N
20 ED -CFine 5ilica (Dow Corning Co., Ltd.) Fransol (Fransi 1 Co., Ltd.) On the other hand, various conventionally known methods can be applied to the method of producing the silica fine powder used in the present invention by a wet method.

For example, the general reaction formula for the decomposition of sodium silicate with an acid is shown below.

Na, 0-XS io, +HC7! +H,0-es i
o, ・nHzo+Nacj'Other methods include decomposition of sodium silicate with ammonia salts or alkali salts, a method of producing alkaline earth metal silicate from 1 noum of sodium silicate and then decomposing it with acid to produce silicic acid, silicic acid There are methods such as converting a sodium solution into silicic acid using an ion exchange resin, and methods using natural silicic acid or silicate.

As the silica fine powder referred to herein, anhydrous silicon dioxide (colloidal silica) and other silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, and silicic acid can be used.

Commercially available fine silicic acid powders synthesized by a wet method include those sold under the following trade names, for example.

Carplex Shiono Gi Seiyaku 21 Pushial Nippon Silica Toxil,
Fine Seal Tokuyama Soda Vita Seal
Multi-wooden fertilizer Jiruton, Silnetkus
Mizusawa Chemical Starsil
Divine Chemical Himezil
Ehime Pharmaceutical Thyroid Fuji Davison Chemical Hi-3il (Hi-Seal) Pittsburgh Plate Glass,
C.

(Pittsburgh Plate Glass) Durosil Ultrasil Fills
toff-Ge5ellschaft Marqu
art (Fürstzuf Keserschaft Markorth) M a no s i I (7 no seal) Hard
man and Ho1den Hoesch Chemische Fabrik Hoesch
K-G (Hiemitsussie Fabrik Herrash)
Sil-5tone Stone
r Rubber Co.

(Stoner Lover) Nalco (Nalco) Nalco Chem, Co. (Nalco Chemical) Quso (Shoes) Philadelphia Quartz Co.

(Philadelphia Quartz) Imsil 111inois Minerals Co.

(Illinois Mineral) Calcium 5ilikat (Calcium Silicate) Chemische Fabrik H
oesch, K-G
Calsil Fiillstoff - Ge5ellschaft
Marquart Fortafil Imperia
l Chemical Industries,L
td.

(Imperial Chemical Industries) Microcal Joseph Crosfields & 5on
s, Ltd.

(Joseph Rosfield Antosans) Manosil (7 Noshir) Hardman and Ho1den (Hardman and Holden) Vulkasil (Pulkasil) Farbenfabriken Bryer, A, -G
(Falpen Fabricen Bayer) Tufknit
(Toughknit) Durham Chemicals, Ltd (Durham Chemicals) Silmos Shiraishi Kogyo Starex Shinshin Kagaku Fricosil
Among the fine silica powders mentioned above, those with a specific surface area due to nitrogen adsorption measured by the BET method within the range of 30 rrf/g or more (particularly 50 to 400 m''/g) give good results.Magnetic Toner 100
It is preferable to use 0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight, of silica fine powder per part by weight.

When the magnetic toner according to the present invention is used as a positively charged magnetic toner, it is preferable to use positively charged silica fine powder rather than negatively charged silica fine powder to be added to prevent wear of the toner. This is preferable because it does not impair charging stability.

As a method for obtaining positively chargeable silica fine powder, the above-mentioned untreated fine silica powder is added with at least one nitrogen atom in the side chain.
There is a method of treatment with a silicone oil having more than one organo group, a method of treatment with a nitrogen-containing silane coupling agent, or a method of treatment with both.

In the present invention, positively charged silica refers to silica that has a positive tripo charge relative to the iron powder carrier when measured by a blow-off method.

As the silicone oil having a nitrogen atom in the side chain used in the treatment of silica fine powder, a silicone oil having at least a partial structure represented by the following formula can be used.

(In the formula, R5 represents hydrogen, an alkyl group, an aryl group, or an alkoxy group, R5 represents an alkylene group or a phenylene group, R3 and R4 represent hydrogen, an alkyl group, or an aryl group, and R5 represents a nitrogen-containing heterocyclic ring. In the above formula, the alkyl group, aryl group, alkylene group, and phenylene group may have an organo group having a nitrogen atom, or may have a substituent such as a halogen within a range that does not impair chargeability. It's okay to do so.

The nitrogen-containing silane coupling agent used in the present invention generally has a structure represented by the following formula.

R, -Si -Yfi (R represents an alkoxy group or a halogen, Y represents an amino group or an organo group having at least one nitrogen atom, m and n are integers of 1 to 3, and m+
n=4. ) Examples of the organo group having at least one nitrogen atom include an amine group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. Examples of the nitrogen-containing heterocyclic group include unsaturated heterocyclic groups and saturated heterocyclic groups, and known ones can be used. Examples of the unsaturated heterocyclic group include the following.

Examples of the saturated heterocyclic group include the following.

The heterocyclic group used in the present invention is preferably a five-membered ring or a six-membered ring in consideration of stability.

Examples of such treatment agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, mono- Butylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-
γ-propylphenylamine, trimethquinsilyl-γ
Examples of such compounds include trimethoxysilyl-γ-propylpiperidine, trimethoxysilyl-γ-propylmorpholine, trimethoxysilyl-γ-propylimidazole.

The application amount of these treated positively charged silica fine powders is
The effect is exhibited when the amount is 0.01 to 8 parts by weight with respect to 100 parts by weight of positively charged magnetic toner, and particularly preferably 0,
When added in an amount of 1 to 5 parts by weight, it exhibits positive chargeability with excellent stability. A preferred form of addition is 0.000 parts by weight per 100 parts by weight of positively charged magnetic toner.
It is preferable that 1 to 3 parts by weight of the treated silica fine powder be attached to the surface of the toner particles. Note that the untreated fine silica powder described above can also be used in the same amount.

The silica fine powder used in the present invention may be treated with a treatment agent such as a silane coupling agent or an organosilicon compound for the purpose of hydrophobization, if necessary, and the above-mentioned treatment that reacts with or physically adsorbs the silica fine powder. treated with an agent. Examples of such treatment agents include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allyl phenyldichlorosilane, and benzyldimethylchlorosilane. Silane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, Dimethyldimethoxysilane, diphenyljethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and having from 2 to 12 siloxane units per molecule, terminal S for each unit located in
There are dimethylpolyrinoxanes containing a hydroxyl group bonded to i. These can be used alone or in a mixture of two or more.

In the magnetic toner according to the present invention, a fine powder of a fluorine-containing polymer may be added internally or externally. Examples of the fluorine-containing polymer fine powder include fine powder of polytetrafluoroethylene, polyvinylidene fluoride, and tetrafluoroethylene-vinylidene fluoride copolymer. In particular, polyvinylidene fluoride fine powder is preferred in terms of fluidity and polishability. The amount added to the toner is 0.01 to 2. 0% by weight, especially 0.02 to 10% by weight is preferred.

In particular, in magnetic toners in which fine silica powder is mixed with the above-mentioned fine powders and externally added, the state of the silica attached to the toner is stabilized, and the attached silica is released from the toner, although the reason is not clear. The effect on toner abrasion and sleeve staining does not decrease, and it is possible to further increase charging stability.

Next, the image forming method and image forming apparatus of the present invention will be explained with reference to FIGS. 7 and 8.

2 is a charging roller as a charging means that is brought into contact with a photoreceptor drum l as an electrostatic image carrier with a predetermined pressure, a conductive rubber layer 2b is provided on a metal core 2a, and a releasable layer is provided on the peripheral surface of the roller. A surface layer 2C, which is a film, is provided. The conductive rubber layer has a thickness of 0. 5~l Omm (preferably 1~5
It is preferable to have a thickness of mm). The surface layer 2C is a releasable film, and it is preferable to provide a releasable film in view of matching with the magnetic toner and image forming method according to the present invention. However, if the resistance is too large, the photoreceptor drum I will not be charged, and if the resistance is too small, too much voltage will be applied to the photoreceptor drum I, which will damage the drum and cause pinholes. It is preferable to have a resistance value (preferably a volume resistivity of 10'' to 101'Ωm).

The thickness of the releasable film at this time is preferably within 30 μm (preferably 10 to 30 μm). The lower limit of the thickness of the releasable film is considered to be about 5 μm, as long as the film does not have any cracks or cracks.

The outer diameter of the charging roller 2 is 12 mmφ. Thickness approx. 3.5
The conductive rubber layer 2b having a diameter of 2 mm is made of ethylene-propylene-
It is a diene-based terpolymer (EPDM). Surface layer 2C
is a nylon resin (specifically, methoxymethylated nylon) with a thickness of 10 μm. The hardness of the charging roller 2 is 54.5° (ASKER-C). Reference numeral 15 denotes a power supply unit that applies voltage to the charging roller 2, and supplies a predetermined voltage to the core metal 2a (diameter 5 mm) of the charging roller 2.

3 is a transfer roller 3 as a transfer means having a core metal 3a and a conductive elastic layer 3b. The conductive elastic layer 3b is made of polyurethane resin or ethylene-propylene-diene terpolymer (EPD) in which a conductive material such as carbon is dispersed.
M) is made of an elastic body having a volume resistance of 106 to 1010 Ω·cm.

A bias is applied to the core metal 3a by a constant voltage power supply 14. The bias condition is a current value of 0.1 to 50μ.
A, voltage (absolute value>100-5000V (preferably 5
00-4000V) is preferable.

A charging roller 2 serving as a charging means having a power supply section (voltage application means) 15 charges the surface of the OPC photoreceptor to, for example, negative polarity, and an electrostatic latent image is formed by exposure 5 . The latent image is developed with, for example, positively charged magnetic toner 10 of the present invention in a developing device 9 equipped with a non-magnetic developing sleeve 4 as a developer carrier containing an iron magnetic blade 11 and a magnet 40. The developing sleeve 2 is a stainless steel sleeve (SUS304) having multiple spherical trace depressions with a diameter of 50 mm.
is used. In the developing section, an alternating bias, a pulse bias, and/or a DC bias is applied between the conductive substrate of the photosensitive drum 1 and the developing sleeve 4 by a bias applying means 12 . When the transfer paper P is conveyed and reaches the transfer section, the transfer roller 3 charges the transfer paper P from the back side (the opposite side to the photosensitive drum side) with the voltage applying means 14, thereby forming a developed image on the surface of the photosensitive drum 1. (toner image) is electrostatically transferred onto transfer paper P. The transfer paper P separated from the photosensitive drum 1 is subjected to a fixing process to fix the toner image on the transfer paper P by a heating and pressure roller fixing device 7 .

Magnetic toner remaining on the photosensitive drum 1 after the transfer process is removed by a cleaning device 8 having a cleaning blade. After cleaning, the photosensitive drum 1 is subjected to erase exposure 6
The charge is removed by the charger 2, and the process starting from the charging process by the charger 2 is repeated again.

The electrostatic image carrier (photosensitive drum) (2) has an OPC photosensitive layer and a conductive substrate, and moves in the direction of the arrow. A non-magnetic cylindrical developing sleeve 4 serving as a toner carrier rotates in the developing section so as to move in the same direction as the surface of the electrostatic image holder. Inside the nonmagnetic cylindrical sleeve 4, a multipolar permanent magnet 40 (magnet roll) serving as a magnetic field generating means is arranged so as not to rotate. The multipolar permanent magnet 40 has magnetic poles N = 500 to 90.
0 Gauss, N2=600~1100 Gauss, S,=80
It is preferable to set S to 0 to 1500 Gauss, and S = 400 to 800 Gauss. The one-component insulating magnetic developer lO in the developing device 9 is applied onto the non-magnetic cylindrical surface, and the toner particles are given, for example, a positive triho charge by friction between the surface of the sleeve 4 and the toner particles. Further, a magnetic doctor blade 11 made of iron is placed close to the cylindrical surface (at a distance of 5
By arranging the toner layer 31 to be thin (30 μm to 300 μm) and uniformly by arranging the toner layer 31 to face one magnetic pole position of the multipolar permanent magnet, the thickness of the toner layer 31 can be controlled to be thin (30 μm to 300 μm) and uniform, and the electrostatic image can be carried in the developing section. body 1 and developer carrier 4
A developer layer thinner than the gap is formed in a non-contact manner. By adjusting the rotation speed of the developer carrier 4, the sleeve surface speed is made to be substantially the same speed as the speed of the electrostatic image holding surface, or a speed close to it. Instead of iron, a permanent magnet may be used as the magnetic doctor blade 11 to form opposing magnetic poles. In the developing section, an alternating current bias or a pulse bias may be applied between the developer carrier 4 and the surface of the electrostatic image carrier 1 by a bias power supply 12 serving as bias means. Bias conditions include AC bias VpI) = 1500 to 2300.
V, f=900 to 1600 ('Hz) and DC bias preferably DC=-100 to -350V. A developing section is formed at the closest point between the developing sleeve (developer carrier) 4 and the electrostatic image carrier 1, and when the toner particles are transferred in the developing section, the electrostatic force of the electrostatic image holding surface is The toner particles are transferred to the electrostatic image carrier 1 while reciprocating between the developing sleeve 4 and the electrostatic image carrier 1 under the action of an alternating current bias or a pulse bias.

Instead of the magnetic doctor blade 11, the toner layer may be formed on the developer carrier 4 by using an elastic plate made of an elastic material such as silicone rubber to regulate the thickness of the toner layer by pressing.

As the electrostatic image carrier 1, an insulating drum for electrostatic recording, α-3e, CdS, ZnO, etc. can be used instead of the OPC photosensitive drum.
, α-3i or the like having a photoconductive insulating material layer can be appropriately selected and used depending on the developing conditions.

As the charging means 2 for charging the electrostatic image carrier 1, a general charger 20 using corona charging as shown in FIG. 9 can be used instead of the charging roller that contacts the surface of the photoreceptor.

Further, the transfer means 3 for electrostatically transferring the developed image on the surface of the electrostatic image carrier 1 to the transfer paper P is replaced by a transfer roller that comes into contact with the transfer paper P, as shown in FIG. A transfer device 30 using corona charging can be used.

As an image forming apparatus, among the above-mentioned components such as an electrostatic image carrier, a developing means, a charging means, and a cleaning means,
A plurality of devices may be combined together as a device unit, and this device unit may be detachably attached to the device body. For example, at least one of a charging means, a developing means, and a cleaning means is integrally supported with an electrostatic image carrier to form a unit, and a guide means such as a rail of the apparatus main body is attached to the main body of the apparatus as an apparatus unit that can be detached from the main body. It may also be configured to be detachably attached. At this time, the above-mentioned device unit may include a charging means and/or a developing means.

When the image forming apparatus of the present invention is used as a facsimile printer, the optical image exposure 5 is digital exposure using a laser beam for printing received data.

FIG. 10 is a block diagram showing an example of this case.

The controller 211 controls the image reading unit 210 and the printer 2.
Controls 19. The entire controller 211 is CPU2
17. The read data from the image reading section is transmitted to the partner station through the transmitting circuit 213. Data received from the partner station is sent to the printer 219 through the receiving circuit 212. Predetermined image data is stored in the image memory. A printer controller 218 controls a printer 219. 214 is a telephone.

The image received from the line 215 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 212, then subjected to image information composite processing by the CPU 217, and sequentially stored in the image memory 216. Ru. When the image of at least one page is stored in the memory 216, the image of that page is recorded. The CPU 217 uses the memory 2
One page of image information is read out from 16 and the decoded one page of image information is sent to the printer controller 218. When the printer controller 218 receives one page of image information from the CPU 218, it controls the printer 219 to record the image information of that page.

The CPU 217 receives the next page while the printer 219 is recording.

As described above, images are received and recorded.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but these are not intended to limit the present invention in any way.

Example 1 The above materials were thoroughly mixed in a blender and then kneaded in a twin-screw kneading extruder set at 150°C. The obtained kneaded material is cooled and coarsely pulverized with a cutter mill, and then finely pulverized using a pulverizer using a jet stream. The mixture was classified to obtain a black fine powder with a volume average diameter of 8.5 μm.

When the surface of the black fine powder was observed using a scanning electron microscope photograph, it was confirmed that it had a particle structure in which many magnetic substances were exposed on the surface, as shown in FIG.

Further, 100 parts by weight of the obtained black fine powder was added with positive charge controllable hydrophobic dry silica (BET specific surface area 200rn2./g).
0. 6 parts by weight were added and mixed in a Henschel mixer to obtain a positively charged insulating magnetic toner.

Electrophotocopy machine NP4835 (manufactured by Canon Corporation)
The magnetic toner was put into a modified machine from which the fixing device had been removed, and an unfixed image was obtained on commercially available copying machine paper as a recording material. The developing conditions at this time were as follows.

・Bias conditions in the developing section: AC voltage = 1800V
, AC frequency = 1300Hz, DC voltage = -200V・
Distance between magnetic blade and developer carrier: 250 μm ・Toner layer thickness on developer carrier, approximately 180 μm ・Bias conditions in transfer means ・Current value = 400 mA, voltage = -
5,6KV ・Magnetic force conditions of the magnet of the developer carrier: N, = 850 Gauss, N2 = 500 Gauss, S, = 1000 Gauss, 52 =
500 Gauss On the other hand, the fixing device removed from N P 4.835 was modified into a temperature-variable heat roller external fixing device, and using this, a fixability test for unfixed images was conducted.

External fuser nip is 40mm, process speed is 1
The speed was set at 50 mm/s, the temperature was adjusted every 5° C. in the temperature range from 100° C. to 230° C., and unfixed images were fixed at each temperature. The obtained fixed image was rubbed with Silbon paper loaded with a load of 50 g/cm 2 , and the fixing temperature at which the image density reduction rate before and after rubbing was 2% or less was defined as the fixing start temperature. As a result, the fixing start temperature was as low as 155° C., indicating excellent low-temperature fixing properties.

In addition, the developing device was removed from the electrophotographic copying machine NP1215 (manufactured by Canon Inc.), the above magnetic toner was put in, and the developing device was rotated idly at a process speed of 150 mm/sec. At each subsequent time, the amount of charge of the toner coated on the sleeve per unit area of the sleeve was measured. Here, the charge amount of the toner layer per unit area on the sleeve was determined using the so-called suction type Faraday cage method.

This suction type Faraday cage method presses the outer cylinder against the sleeve to suction all the toner on a certain area on the sleeve, and collects it in a cylinder that has a built-in filter and is electrostatically shielded from the outside. By measuring the amount of charge accumulated in the inner cylinder, the amount of charge per unit area on the sleeve can be determined.

As a result, the amount of charge per unit area on the sleeve (r1c/
cm") was initially 72.0, and although it increased slightly to 85 after 5 hours, it was still 8.4 after 3 hours, indicating stable charge control performance in the durability of the toner.

Furthermore, NP l in a low humidity environment (i degree 10% RH)
Pour the above magnetic toner into the phenomenon device No. 215 and let it idle for 2 seconds.
Observe the unevenness (non-uniformity) of the toner coat layer on the sleeve, and turn off the developing device after 2 hours of idle rotation.
It was attached to the P121D main body, an image was produced, and the image characteristics were observed.

As a result, no toner coating unevenness occurred on the sleeve even after two hours of idle rotation, and a clear image without unevenness or fog was obtained even after the idle rotation.

Further, the above magnetic toner was left in a dryer at 50° C. for 3 days to test the blocking resistance of the toner, but no problems were found. The results are shown in Table 1.

Example 2 Example 1 except that the binder resin A used in Example 1 was changed to 70 parts by weight and the binder resin B1 was changed to 30 parts by weight.
A magnetic toner was prepared and evaluated in the same manner as above.

As a result, as shown in Table 1, it had excellent low-temperature fixing properties as in Example 1, the amount of charge on the sleeve was stable, and the uniformity of the toner coat layer on the sleeve was also good in a low-humidity environment. There were no problems with blocking.

Example 3 A magnetic toner was prepared and evaluated in the same manner as in Example 1, except that the binder resin A1 used in Example 1 was changed to 95 parts by weight, and the binder resin B1 was changed to 5 parts by weight.

As a result, as shown in Table 1, similar to Example 1, excellent low-temperature fixing properties were exhibited. On the other hand, the amount of charge on the sleeve (nc/c
Although m') has increased slightly from 6.9 at the initial stage to 10.2 after 05 hours, it is still 10.0 after 3 hours.
Although Example 1 was not as good as it was, relatively stable charge controllability of the toner was demonstrated.

Furthermore, as in Example 1, under a low humidity environment (humidity 10% RH)
) When the toner coat layer on the sleeve of the toner was observed, it was found that slight unevenness had occurred, but when image printing was performed using an electrophotographic copying machine NP1215 in the same manner as in Example 1, no unevenness or fog was observed. A clear image with no defects was obtained, and there were no sleeve irregularities that would pose a practical problem.

There was also no problem with the blocking properties of the toner.

Comparative Example 1 A magnetic toner was prepared and evaluated in the same manner as in Example 1, except that the binder resin B1 used in Example 1 was changed to 100 parts by weight.

As shown in Table 2, the low-temperature fixability was good, but with the above magnetic toner, the amount of charge on the sleeve was significantly higher after 0.5 hours compared to the initial state, and further increased after 3 hours. It was observed that the charge control performance due to durability was unstable and there was a tendency for charge-up to occur.

Furthermore, in a low-humidity environment, the toner coating layer became severely uneven on the sleeve after idle rotation, and the image formed with NP1215 showed fogging and unevenness over the entire surface, making it unsuitable for practical use. Other than that, there were no problems with blocking resistance. Incidentally, FIG. 2 shows a scanning electron micrograph of the surface of the black fine powder before adding the positive charge control hydrophobic dry silica at the stage of producing the magnetic toner. As shown in this figure, it was observed that most of the magnetic material had a particle structure buried in the surface.

Comparative Example 2 Example 1 except that the binder resin A1 used in Example 1 was changed to 50 parts by weight, and the binder resin B1 was changed to 50 parts by weight.
A magnetic toner was prepared and evaluated in the same manner as above. As a result, as shown in Table 2, although the stability of the charge amount on the sleeve and the uniformity of the toner coating layer on the sleeve in a low-humidity environment were good, the fixing start temperature increased and the low-temperature fixing performance was poor. Ta.

Example 4 The following binder resin A2 was used in place of the binder resin A1 used in Example 1.
A magnetic toner was produced and evaluated in the same manner as in Example 1, except that %, ■ value 4.5) was used. As a result, as shown in Table 1, it had excellent low-temperature fixability, the amount of charge on the sleeve was stable, the uniformity of the coating layer on the sleeve was good even in a low humidity environment, and there were no problems with blocking properties.

(Hereinafter referred to as "margin") (2/ Example 5 The following binder resin A was used in place of the binder resin 〇 used in Example ①.

Binder resin A3 (weight fraction of molecular weight components of 500 to 20,000 in molecular weight distribution by GPC measurement: 77
A magnetic toner was produced and evaluated in the same manner as in Example 1, except that Ml value (Ml value: 15.0) was used. Results table 1
As shown in the figure, low temperature fixability, stability of charge amount on the sleeve,
The uniformity of the coating layer on the sleeve was all good under a low humidity environment. In addition, although the blocking resistance was slightly inferior, it was not to the extent that it would cause a particular problem in practical use.

Comparative Example 3 The following binder resin A4 was used in place of the binder resin A1 used in Example 1. Binder resin A4 (molecular weight distribution by GPC measurement: 5
00 to 20.00017) Weight fraction of molecular weight component: 4
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 7% MI [4,3) was used. As shown in Table 2, the stability of the charge amount on the sleeve and the uniformity of the coating layer on the sleeve in a low-humidity environment were good, but the fixing start temperature increased and the low-temperature fixing performance was poor. Ta.

Comparative Example 4 The following binder resin A5 was used in place of the binder resin A1 used in Example 1. Binder resin A, (5 in molecular weight distribution by GPC measurement)
Weight fraction of molecular weight components from 00 to 20.000 feather%,
A magnetic toner was produced and evaluated in the same manner as in Example 1 except that the Ml value was 13.5). As a result, as shown in Table 2, the blocking resistance was poor and it was not practical. Furthermore, the amount of charge on the sleeve increased (decreased) after 3 hours of idle rotation, making it impossible to obtain stable charge control, and fogging occurred on the image after 3 hours of idle rotation.

Example 6 80 parts by weight of the binder resin A used in Example 5 and 8220 parts by weight of the following binder resin Binder resin B2 (
THF insoluble content: 84.5% by weight, MI value: 0.08)・
A magnetic toner was prepared and evaluated in the same manner as in Example 1, except that a thretin/butadiene/divinylbenzene copolymer (copolymerization weight ratio: 75.8/23.510.7) was used.

Example 7 The following binder resins A and B were used in place of binder resins A and B1 used in Example 1.

Binder resin A, (molecular weight distribution by GPC measurement: 5
Weight fraction of molecular weight components from 00 to 20.000 is near 8%
, MI117.7) Binder resin Bs (THF-insoluble content: 9% by weight, MI value: 1.5) - Thretin/butadiene/divinylbenzene copolymer (copolymerization weight ratio + 82
．． 85/710.15) 20
A magnetic toner was produced and evaluated in the same manner as in Example 1, except that weight % was used.

The results of Examples 6 and 7 are shown in Table 1, and all of the magnetic toners had good low-temperature fixability, stability of the amount of charge on the sleeve, and uniformity of the toner coat layer on the sleeve. Furthermore, although the anti-blocking properties of all magnetic toners were slightly inferior, they were not at a level that would pose a particular problem in practical use.

Further, although the magnetic toner of Example 7 caused some fogging due to idle rotation in a low humidity environment, it was not at a level that would cause any particular problem in practical use.

+1. \ Example 8 The following binder resins A7 and B4 were used in place of the binder resins A1 and B1 used in Example 1.
(500 to 20.0 in molecular weight distribution by GPC measurement
00 (7) Weight fraction of molecular weight component = 66%, MI value 1
23) Binder resin B, (THF insoluble content = 0.1
, MI value: 5. A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that Q) was used. As a result, as shown in Table 1, similar to Example 1, excellent low-temperature fixability was exhibited. Although the stability of the amount of charge on the sleeve and the uniformity of the toner coating layer on the sleeve in a low-humidity environment were somewhat inferior, they were not at a level that would pose a practical problem. There was also no problem with blocking performance.

Example 9 In place of the binder resins A1 and B1 used in Example 1, 280 parts by weight of the binder resin A used in Example 4 and 520 parts by weight of the following binder resin B 5
(THF-insoluble content: 0.1% by weight, ■ value: 2.0) - Thretin/butadiene copolymer (copolymerization weight ratio: 76.
A magnetic toner was prepared and evaluated in the same manner as in Example 1, except that 5/23.5) was used. As shown in Table 1, the low temperature fixability was excellent. Charge amount on sleeve,
The uniformity and blocking resistance of the toner coat layer on the sleeve under low humidity were both slightly inferior, but not at a level that would pose a practical problem.

Comparative Example 5 In place of 120 parts by weight of binder resin B used in Example 1, 20 parts by weight of the following binder resin B 6 (THF insoluble content = 42% by weight, ■ value: O1), styrene/butyl acrylate/divinyl A magnetic toner was prepared and evaluated in the same manner as in Example 1, except that a benzene copolymer (copolymerization weight ratio: 70/3010.5) was used.

As a result, as shown in Table 2, the fixing start temperature was slightly increased, and the amount of charge on the sleeve was unstable and easily charged up, and in a low humidity environment, unevenness occurred in the toner coating layer on the sleeve after idling. Fog and unevenness were seen all over the image, making it unusable for practical use. There was no problem with blocking resistance.

Comparative Example 6 In place of binder resins A1 and B1 used in Example 1, 780 parts by weight of binder resin A used in Example 8 and 720 parts by weight of binder resin B below were used.
THF insoluble content = 0.1% by weight or less, MI value near, 0) Styrene/butadiene copolymer (copolymerization weight ratio: 9
A magnetic toner was produced and evaluated in the same manner as in Example 1 except that 3/7) was used. As a result, as shown in Table 2, the fixing performance has improved slightly, and in addition, the amount of charge on the sleeve is unstable and charge-up is likely to occur, and in a low humidity environment, unevenness occurs in the toner coat layer on the sleeve after idling, and the image There was fog and unevenness all over the top, and it was not suitable for practical use. There was no problem with blocking resistance.

Comparative Example 7 In place of the binder resin B+ used in Example 1, the following binder resin B8 was used. Binder resin B, (THF insoluble content 51% by weight, MI
old value)・thretin/butadiene/divinylbenzene copolymer copolymerization weight ratio 69.4/3010.6) 20
A magnetic toner was produced and evaluated in the same manner as in Example 1 except that parts by weight were used.

As a result, as shown in Table 2, the blocking resistance was poor and it was not suitable for practical use. Furthermore, the amount of charge on the sleeve tended to decrease due to idle rotation of the paper, and fogging occurred when an image was produced using the developing device after 3 hours of idle rotation.

Comparative Example 8 Comparative Example 3 was used instead of binder resin A used in Example 1.
A magnetic toner was produced and evaluated in the same manner as in Example 1 except that 480 parts by weight of the binder resin Δ used in Example 1 was used. As a result, as shown in Table 2, the amount of charge on the sleeve was unstable and charge-up was likely to occur, and in a low-humidity environment, unevenness occurred in the toner coating layer on the sleeve after idle rotation, making it unsuitable for practical use.

Example 10 As a fixing aid, 3 parts by weight of a graft-modified polyolefin (styrene content: 2% by weight, butyl acrylate content: 2% by weight) prepared by graft copolymerizing low molecular weight polyethylene with styrene and butyl acrylate was further added. A magnetic toner was prepared and evaluated in the same manner as in Example 1 except for the following. The results are shown in Table 1. The fixing start temperature was further lower than that of Example 1, and the low-temperature fixing properties were extremely excellent.

However, although the blocking property was slightly inferior, it was not a problem in practical use, and all other aspects were good.

Incidentally, FIG. 5 shows a scanning electron micrograph of the surface of the black fine powder before adding the positive charge control hydrophobic dry silica at the stage of producing the magnetic toner.

As can be seen from this figure, it was confirmed that the particle structure has a large amount of magnetic material exposed on the surface.

Example 11 Instead of the fixing aid used in Example 10, a graft-modified polyolefin obtained by graft copolymerizing low molecular weight polyethylene with styrene and butyl acrylate (styrene content = 1% by weight, butyl acrylate content: 1% by weight) %
) A magnetic toner was prepared and evaluated in the same manner as in Example 10, except that the magnetic toner was used.

Example 12 Instead of the fixing aid used in Example 10, a graft-modified polyolefin (styrene content: 16% by weight, butyl acrylate content: 1216% by weight) was obtained by graft copolymerizing low molecular weight polyethylene with styrene and butyl acrylate. A magnetic toner was produced and evaluated in the same manner as in Example 10 except that the following was used.

As shown in Table 1, both Examples 11 and 12 were good.

Example 13 Instead of the fixing aid used in Example 10, a graft-modified polyolefin obtained by graft copolymerizing low molecular weight polyethylene with styrene and butyl acrylate (styrene content = 20.5% by weight, butyl acrylate content = 0.
A magnetic toner was prepared and evaluated in the same manner as in Example 10 except that 5% by weight) was used.

Example 14 Instead of the fixing aid used in Example 10, a graft-modified polyolefin obtained by graft copolymerizing low molecular weight polyethylene with styrene and butyl acrylate (styrene content = 23% by weight, butyl acrylate content, 23% by weight) A magnetic toner was produced and evaluated in the same manner as in Example 1O except that %) was used.

As shown in Table 1, both Examples 13 and 14 had better low-temperature fixability than Example 1, and the effect of the fixing aid was recognized. Other results were also good.

Comparative Example 9 As a fixing aid, 3 parts by weight of graft-modified polyolefin (styrene content = 2% by weight, butyl acrylate content: 2% by weight) prepared by graft copolymerizing low molecular weight polyethylene with styrene and butyl acrylate was further added. A magnetic toner was produced in the same manner as in Comparative Example 1, except for the above, and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Although the low-temperature fixability is excellent, the increase in the amount of charge on the sleeve is significant, and the unevenness of the toner coating layer on the sleeve under low humidity environments is extremely severe, and the charge controllability of the magnetic toner is poor. , it was extremely bad.

Incidentally, FIG. 3 shows a scanning electron micrograph of the surface of the black fine powder before adding the positively charge-controlling hydrophobic dry silica at the stage of producing the magnetic toner.

As can be seen from this figure, it was confirmed that the toner had a particle structure in which the magnetic material was hardly exposed on the surface.

FIG. 6 shows the relationship between the weight percent of the conjugated diene monomer component contained in the binder resin (B) of the magnetic toner in Examples and Comparative Examples and the absolute value of the difference in melt index between the binder resins (A) and (B). Shown below.

5-＼ [Effects of the Invention] According to the magnetic toner of the present invention, it has excellent low-temperature fixing performance compared to hot roll fixing, and also maintains sleeve retention over a long period of time even under different environmental conditions with respect to jumping development. A magnetic toner having a uniform upper toner coat layer and stable charge control performance can be obtained.

According to the image forming method of the present invention, it is possible to maintain an excellent toner image and fixability to a recording material, and also to achieve shortening of wait time and low power consumption.

According to the image forming apparatus of the present invention, it is possible to form images having excellent image characteristics over a long period of time even under different environmental conditions such as low humidity and high humidity.

According to the apparatus unit of the present invention, it is possible to form an image having excellent image characteristics over a long period of time even under different environmental conditions such as low humidity and high temperature by being detachably attached to the apparatus main body.

According to the facsimile apparatus of the present invention, image information from a remote terminal can be output as an image having excellent image characteristics over a long period of time even under different environments.

[Brief explanation of the drawing]

Figure 1 shows a scanning electron micrograph at a magnification of 10,000 times showing the particle structure of a magnetic toner that does not contain a low molecular weight polymer in the binder resin, and Figure 2 shows a scanning electron micrograph showing the particle structure of a magnetic toner that does not contain a low molecular weight polymer in the binder resin. FIG. 3 shows a scanning electron micrograph at a magnification of 10,000 times showing the particle structure of the magnetic toner of Comparative Example 1 containing coalescence. A scanning electron micrograph at a magnification of 10,000 times showing the particle structure of the toner of Comparative Example 6 containing a modified polyolefin is shown in FIG. FIG. 5 shows a scanning electron micrograph at a magnification of 10,000 times showing the particle structure of a magnetic toner of the present invention. A scanning electron micrograph at a magnification of 10,000 times is shown showing the particle structure of the magnetic toner of Example 19 containing polyolefin, and FIG. 6 shows the weight percent of the conjugated diene monomer component contained in the binder resin (B). and the absolute value of the difference in melt index of binder resins (A) and (B).
FIG. 7 shows a schematic configuration diagram for explaining the image forming apparatus and image forming method of the present invention, FIG. 8 shows a partially enlarged view of FIG. 7 for explaining the developing process, and FIG. FIG. 7 shows a schematic configuration diagram of another embodiment of the image forming apparatus, and FIG. 10 shows a block diagram of a facsimile machine that uses the electrophotographic apparatus as a printer. 1... Electrostatic image carrier 2... Charging means 3... Transfer means 7... Fixing means 9... Developing means 10... Magnetic toner \・Kokono' V v3ze (・) （＼； wa、・、゛ ゝ－・－・´PIN＼ １ ＼ 7 -・１．、： '、、 ℃
~; 2, (ν゛\W '(,, -/' \--, +l ,'To'/' Notebook 8

Claims (6)

[Claims] (1) In a magnetic toner containing at least a binder resin and a magnetic material, the binder resin (A) has a molecular weight distribution of 500 to 20,000 as determined by GPC (gel permeation chromatography) measurement of THF-soluble content. 6. Vinyl binder resin (A) containing 50 to 80% by weight of molecular weight components
0 to 97% by weight, and (B) 3 to 4% of the binder resin (B) synthesized from at least a conjugated diene monomer.
0% by weight, and the respective melt index values (a) and (b) of the binder resin (A) and binder resin (B) are expressed by the following formula |a-b|=-
0.15x+k (In the formula, a represents the melt index value of the binder resin (A), b represents the melt index value of the binder resin (B), and x represents the melt index value of the binder resin (B). (% by weight of a conjugated diene monomer; k is a positive number from 5 to 25; and k is an integer from 5 to 20). (2) The magnetic toner according to claim (1), which contains a vinyl-based graft-modified polyolefin as a fixing aid. (3) An electrostatic charge image carrier that carries an electrostatic charge image on its surface and a developer carrier that holds magnetic toner on its surface are arranged at a constant interval in a developing section, and the electrostatic charge image is disposed in a developing section. A developed image is formed by transferring magnetic toner to a carrier, and the formed developed image is transferred to a recording material with a charge of the same polarity as the electrostatic charge image, and the unfixed toner image on the transfer material is removed by heat and pressure. In an image forming method in which an image is formed by fixing on a recording material, (A) the molecular weight distribution of the THF soluble portion measured by GPC (gel permeation chromatography) is 500 to 2;
60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of a molecular weight component of 0,000, and (B) 3 to 40% of a binder resin (B) synthesized from at least a conjugated diene monomer. % by weight, and the respective melt index values (a) and (b) of the binder resin (A) and binder resin (B) are expressed by the following formula |a-b|=-0.15x+k ( In the formula, a represents the melt index value of the binder resin (A), b represents the melt index value of the binder resin (B), and x represents the conjugated diene monomer in the monomers for synthesizing the binder resin (B). is a positive number from 5 to 25, and k is an integer from 5 to 20), and a magnetic material. Characteristic image forming method. (4) An electrostatic charge image carrier for carrying an electrostatic charge image, a charging means for charging the electrostatic charge image carrier, and developing the electrostatic charge image carried on the electrostatic charge image carrier. a developing means for transferring the developed image developed by the developing means from the electrostatic image carrier to the recording material; In an image forming apparatus having a fixing means for fixing to a recording material by a developer, the developing means has a developer carrier holding magnetic toner on its surface, which is arranged at a constant distance from the electrostatic charge image carrier. The magnetic toner contains at least a binder resin and a magnetic material, and the binder resin includes (A)
Molecular weight distribution of THF-soluble components measured by GPC (gel permeation chromatography) is 500 to 20.0.
60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of a molecular weight component of 00;
) A resin mixture containing 3 to 40% by weight of a binder resin (B) synthesized from at least a conjugated diene monomer, and each of the binder resin (A) and the binder resin (B) has a melt index value (a )as well as(
b) is the following formula |a-b|=-0.15x+k (where a represents the melt index value of the binder resin in (A), b represents the melt index value of the binder resin in (B), and x is The weight percent of the conjugated diene monomer in the monomers used to synthesize the binder resin (B) is 5 to 25
(k is a positive number from 5 to 20). (5) An electrostatic charge image carrier for carrying an electrostatic charge image, a charging means for charging the electrostatic charge image carrier, and developing the electrostatic charge image carried on the electrostatic charge image carrier. A developing means for the recording material is integrally supported to form a unit, and the unit includes a transferring means for transferring the developed image developed by the developing means from the electrostatic image carrier to the recording material, In a device unit that is detachably attached to an apparatus main body and includes a fixing means for fixing an unfixed toner image transferred to a recording material to a recording material by heat and pressure, the developing means is configured to carry the electrostatic charge image. It has a developer carrier holding magnetic toner on its surface, which is disposed at a constant distance from the developer carrier, and the magnetic toner contains at least a binder resin and a magnetic material, and the binder resin includes: (A)
Molecular weight distribution of THF-soluble components measured by GPC (gel permeation chromatography) is 500 to 20.0.
60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of a molecular weight component of 00;
) A resin mixture containing 3 to 40% by weight of a binder resin (B) synthesized from at least a conjugated diene monomer, and each of the binder resin (A) and the binder resin (B) has a melt index value (a )as well as(
b) is the following formula |a-b|=-0.15x+k (where a represents the melt index value of the binder resin in (A), b represents the melt index value of the binder resin in (B), and x is The weight percent of the conjugated diene monomer in the monomers used to synthesize the binder resin (B) is 5 to 25
is a positive number, and k is an integer from 5 to 20). (6) an electrostatic charge image carrier for carrying an electrostatic charge image, a charging means for charging the electrostatic charge image carrier, and a charging means for being carried on the electrostatic charge image carrier; a developing means for developing the electrostatic image carried on the electrostatic image carrier; and a transfer means for transferring the developed image developed by the developing means from the electrostatic image carrier to a recording material. , an electrophotographic apparatus having a fixing means for fixing an unfixed toner image transferred to the recording material onto the recording material by heat and pressure, and a facsimile apparatus having a receiving means for receiving image information from a remote terminal. In the above, the developing means includes:
It has a developer carrier holding magnetic toner on its surface, which is disposed at a constant distance from the electrostatic image carrier,
The magnetic toner contains at least a binder resin and a magnetic material. 60 to 97% by weight of a vinyl binder resin (A) containing 50 to 80% by weight of molecular weight components, and (B) a binder resin synthesized from at least a conjugated diene monomer (B).
) in an amount of 3 to 40% by weight,
The melt index values (a) and (b) of the binder resin (A) and binder resin (B) are expressed by the following formula |
a-b|=-0.15x+k (In the formula, a represents the melt index value of the binder resin (A), b represents the melt index value of the binder resin (B), and x represents the melt index value of the binder resin (B). is a positive number from 5 to 25, and k is an integer from 5 to 20).