JPH0830015A - Magnetic toner and electrophotographic method - Google Patents

Abstract

PURPOSE:To obtain a magnetic toner which produces no toner filming by using a specified org. photosensitive body and a magnetic toner comprising silica fine particles and polyvinylidene fluoride fine particles as an external additive. CONSTITUTION:This photosensitive body is such an org. photosensitive body that at least its surface layer contains a polycarbonate resin, org. photoconductive material and additive (silicone oil) expressed by formula I. Moreover, the magnetic toner consists of at least a binder resin, magnetic material and external additive. This external additive consists of hydrophobic silica fine particles the surface of which is treated with a treating agent expressed by formula I and fine particles (polyvinylidene fluoride fine particles) expressed by formula II. The external additive used for the magnetic toner is obtd. by subjecting hydrophobic silica fine particles obtd. by processing silicon tetrachloride with silicone oil to surface treatment with silicone oil. The surface treatment of silica fine particles is performed by a well-known method such as a mixing or spraying method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic toner used in copying machines, printers and facsimiles, and an electrophotographic method.

[0002]

2. Description of the Related Art In recent years, electrophotographic devices have been shifting from the purpose of office use to personal use, and there is a demand for a technique for realizing downsizing and maintenance-free operation.

A printing process of an electrophotographic copying machine or printer will be described. First, an electrostatic latent image carrier (hereinafter referred to as a photoconductor) is charged for image formation. As a charging method, a conventionally used corona charger is used, and in recent years, a contact type charging method in which a conductive roller is directly pressed against the photoreceptor to reduce the amount of ozone generation is used. A means for uniformly charging the surface has been put into practical use. After the photoconductor is charged, in the case of a copying machine, a copy original is irradiated with light and reflected light is radiated to the photoconductor through a lens system to form a latent image. Alternatively, in the case of a printer, an image signal is sent to a light emitting diode or a laser diode as an exposure light source, and an electrostatic latent image is formed on the photoconductor by turning the exposure light source on and off. The electrostatic latent image on the photoconductor is visualized with toner (having a diameter of about 5 to 15 μm) which is a pre-charged colored powder. After that, it is electrically transferred to the image receiving paper. That is, the toner is charged positively or negatively in advance, and is electrically attracted by applying a charge having a polarity opposite to the toner polarity from the back surface of the image receiving paper. Up to now, a corona discharger has been widely used as the charge applying method as in the charging method, but in recent years, a transfer device using a conductive roller has been put into practical use in order to reduce the ozone generation amount. Further, at the time of transfer, not all the toner on the photoconductor is transferred to the image receiving paper, but a part of the toner remains on the photoconductor. This residual toner is scraped off by a cleaning blade or the like in the cleaning section and becomes waste toner.

Conventionally, there are a cascade developing method, a touchdown developing method, a jumping developing method and the like as a developing method for making an electrostatic latent image visible by an electrophotographic method. Among them, as a developing method in which a developer is directly sprinkled on a photoreceptor, US Pat.
The cascade development shown in 105770 is known. The cascade developing method is the first developing method used in an electrophotographic copying machine. Also, there is US Pat. According to the present invention, the AC bias applied to the developing roller is used for the purpose of activating the movement of the toner, and the toner flies to the image portion and returns to the middle portion in the non-image portion.

Further, as an improved technique for applying the AC bias, there is a jumping developing method disclosed in Japanese Patent Publication No. 63-42256. In this jumping developing method, toner is carried on a toner carrier and conveyed to a developing unit, where the toner is attached to the image part of the photoconductor by an AC bias. This special public Sho 63-4225
The technical idea of Japanese Patent No. 6 is that the toner reciprocates in the image portion and the non-image portion in the above-mentioned US Pat.
It is different from 574.

In order to further miniaturize the development and improve the image quality, a fixed magnet is included in the photosensitive member, and the electrode roller is provided with a magnet at a position facing the electrostatic latent image holding member with a predetermined gap. Developing method (Japanese Patent Laid-Open No. 5-72890)
Has been proposed, and further higher image quality, smaller size, simplified device, and lower cost are possible.

As is well known, the toner for developing an electrostatic latent image used in these developing methods is generally composed of a resin component, a coloring component composed of a pigment or a dye, and an additive component such as a plasticizer and a charge control agent. Has been done. A natural or synthetic resin is used as a resin component, or is mixed as appropriate, and is composed of hydrophobic silicon dioxide fine particles (hereinafter referred to as hydrophobic silica fine particles) as an external additive.

A large number of silanol groups are present on the surface of the silica fine particles, and since moisture is adsorbed to the silanol groups under high humidity, the toner has a low charge amount. Therefore, a silane coupling agent is generally used to make the surface of the silica fine particles hydrophobic. Silane coupling agents such as dimethyldichlorosilane and hexamethyldisilazane are generally used as the treating agent.

Conventionally, the photoreceptor is subjected to electrical, mechanical and thermal stress during each process of electrophotography. For example, there are charging, development with toner, transfer to paper, and cleaning process for removing the transfer residual toner. Therefore, when the electrophotographic process is repeatedly performed, problems such as scratches and abrasion due to mechanical external force occur. All of these deteriorate the image quality, and it is not possible to always obtain a stable and clear image.

The above-mentioned problems are caused by the fact that the binder resin on the surface layer of the photoconductor (hereinafter, the binder resin for the photoconductor and the binder resin for the toner become confusing, so that the binder resin for the photoconductor is bound to the photoconductor. Resin and binder resin for toner are referred to as toner binder resin.) Therefore, the selection of the photoreceptor binder resin for the photoreceptor surface layer is very important, and at the same time, it is extremely difficult to satisfy all the requirements for the photoreceptor in the electrophotographic process. So far, as the ones used for the photoreceptor binder resin, methacrylic resins, acrylic resins, polystyrenes, polyesters, polycarbonates, polyacrylates, polysulfones, and other single products, or copolymers and blends have been proposed. Among them, polycarbonate has comprehensively excellent properties and has already been put to practical use. When polycarbonate is used as a photoreceptor binder resin, deterioration of electrophotographic characteristics such as increase in residual potential due to continuous use is small,
An electrostatic latent image can be stably obtained. Further, since it is excellent in abrasion resistance, it is also characterized by being excellent in durability against various mechanical stresses.

[0011]

However, in the above-structured organic photoreceptor containing a polycarbonate resin in the surface layer of the photoreceptor, silica fine particles added as an external additive to the toner are pressed by a cleaning blade to form a photoreceptor. Buried on the surface. Due to the high abrasion resistance of the polycarbonate resin, since the surface of the photoconductor is not polished, it is difficult to remove the silica fine particles embedded in the surface of the photoconductor. Therefore, the frictional resistance of the photoconductor in the portion where the silica fine particles are buried becomes large, and the toner is fixed to the photoconductor by the pressing of the cleaning blade. A so-called toner filming phenomenon occurs. When toner filming occurs, light is blocked during exposure according to an image pattern, and an electrostatic latent image is not formed. When a copy original is irradiated with light and reflected light is formed on the photoconductor through the lens system to form an electrostatic latent image, the non-image portion is not exposed and the toner is developed. A so-called fogging phenomenon occurs. Further, when a light emitting diode or a laser diode is used as an exposure light source, an electrostatic latent image is not formed on the toner filming portion, and white spots occur on the image. As described above, the photoreceptor containing the polycarbonate resin has a problem that toner filming occurs.

Further, in the developing method, which is well known in the art, the cascade developing method is not good at reproducing solid images. Further, there is a problem that the device becomes large and complicated. Further, the developing device of U.S. Pat. No. 3,866,574 has the drawback that the device requires high accuracy, is complicated, and is expensive. In the jumping development method, it was essential to form a very uniform thin layer on the toner carrier carrying the toner layer. Further, in this method, a so-called sleeve ghost phenomenon occurs in which the history of the previous image remains in the thin toner layer on the toner carrier and an afterimage appears in the image. Further, there is a drawback that the device is complicated and the cost is high.

Therefore, an electrophotographic method of the present invention (Japanese Patent Laid-Open No. 5-72890) has been proposed, which can realize development of a smaller size and higher performance. The developing method of the electrophotographic method is configured to remove unnecessary toner in a non-image area by a photoconductor containing a fixed magnet and a toner recovery electrode roller (hereinafter referred to as an electrode roller) having a predetermined gap with the photoconductor. Therefore, this developing method faithfully reproduces a solid image, does not cause a sleeve ghost, and is a method that enables further downsizing, simplification, and cost reduction of the apparatus.

However, in the electrophotographic method of the present invention, in order to adhere the toner to the entire photoreceptor and convey it during development,
Compared with the conventional one-component developing method, the toner and the photoconductor are in contact with each other for a longer period of time. Since a magnetic substance is internally added to the toner, it is necessary to reduce damage to the magnetic substance of the photoconductor. Therefore, a photoreceptor having high mechanical strength and excellent electrical characteristics for forming an electrostatic latent image is required.
Polycarbonate resin is the most suitable material because it has excellent mechanical durability and electrophotographic characteristics. However, if silica fine particles are buried in the surface of the photoreceptor, the wear resistance is high.
Filming problems occur.

Further, the electrophotographic system of the present invention has a constitution in which the toner in the non-image area is removed from the surface of the photoconductor by a collecting roller containing a magnet. When the magnetic force of the magnet contained in the collecting roller of this configuration is increased, the image density is lowered. Also,
When the magnetic force of the magnet contained in the collecting roller is weakened to secure the image density, there is a problem that fogging occurs in the non-image portion. In view of the above problems, it is an object of the present invention to provide a magnetic toner in which toner filming does not occur, and an electrophotographic method which realizes high image quality, downsizing, simplification, and cost reduction of the apparatus. .

[0016]

In order to solve the above problems, the magnetic toner and the electrophotographic method of the present invention have the following configurations.

The photoconductor is an organic photoconductor containing at least a polycarbonate resin, an organic photoconductive substance and an additive represented by the general formula (Formula 1) (hereinafter referred to as silicone oil) in the surface layer, and the magnetic toner is It comprises at least a binder resin, a magnetic substance and an external additive, and the external additive is at least a hydrophobic silica fine particle surface-treated with a treating agent represented by the general formula (Formula 1) and a general formula (Formula 2). The magnetic toner comprises fine particles (hereinafter referred to as polyvinylidene fluoride fine particles).

Further, the present invention is a magnetic toner characterized in that the photoconductor is an organic photoconductor formed by sequentially laminating a charge generation layer and a charge transport layer on a conductive support.

Furthermore, the present invention is a magnetic toner characterized in that the amount of silicone oil added to the photoreceptor is 0.01 to 3.0 parts by weight with respect to 100 parts by weight of the charge transport layer.

Further, the present invention is the magnetic toner characterized in that the addition amount of the magnetic material is 15 to 70% by weight based on the weight of the magnetic toner.

Further, the present invention is a magnetic toner characterized in that the addition amount of the hydrophobic silica fine particles is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the magnetic toner.

Further, the present invention is a magnetic toner characterized in that the hydrophobic silica fine particles have a specific surface area of 50 to 300 m ² / g.

Further, in the present invention, the addition amount of polyvinylidene fluoride fine particles is 0.01 per 100 parts by weight of the magnetic toner.
It is a magnetic toner characterized in that the amount is up to 3.0 parts by weight.

Further, the present invention is a magnetic toner characterized in that the specific surface area of the polyvinylidene fluoride fine particles is 2.0 to 25.0 m ² / g.

Further, the present invention is a magnetic toner characterized in that the fine particles of polyvinylidene fluoride have a volume average particle diameter of 3 to 20 μm.

Further, the present invention is a magnetic toner characterized in that the polyvinylidene fluoride fine particles are produced by emulsion polymerization.

Further, the present invention is a one-component toner. The present invention also includes a movable photoconductor that includes a fixed magnet,
A toner hopper and a toner collecting electrode roller having a magnet inside are provided at a position having a predetermined gap from the surface of the photoconductor, and after forming an electrostatic latent image on the photoconductor, the toner hopper is placed in the toner hopper. Magnetic toner is magnetically attracted to the surface of the photoconductor located at, the magnetic toner is carried on the surface of the photoconductor, the photoconductor is moved, and is opposed to the toner recovery electrode roller. The toner is left in the image portion of the non-image portion, the toner of the non-image portion is an electrophotographic method having a developing step of collecting by the toner collecting electrode roller, wherein the photoreceptor has at least a polycarbonate resin and an organic photoconductive material on the surface layer. An organic photoreceptor containing silicone oil, and the magnetic toner comprises at least a binder resin, a magnetic body and an external additive, and the external additive is at least silicone oil. A surface treated hydrophobic silica fine particles, an electrophotographic method characterized by using the magnetic toner composed of polyvinylidene fluoride fine particles.

Further, the present invention is the electrophotographic method, wherein the photoconductor is an organic photoconductor formed by sequentially laminating a charge generation layer and a charge transport layer on a conductive support.

Further, the present invention is the electrophotographic method, wherein the amount of silicone oil added to the photoreceptor is 0.01 to 3.0 parts by weight with respect to 100 parts by weight of the charge transport layer. .

Furthermore, the present invention is an electrophotographic method characterized in that a magnetic toner containing 15 to 70% by weight of a magnetic substance is used with respect to the weight of the magnetic toner.

Furthermore, the present invention is an electrophotographic method characterized in that the amount of hydrophobic silica fine particles added is 0.1 to 5.0 parts by weight based on 100 parts by weight of the magnetic toner.

Further, the present invention is an electrophotographic method characterized by using a magnetic toner in which the specific surface area of the hydrophobic silica fine particles is 50 to 300 m ² / g.

Further, in the present invention, the addition amount of polyvinylidene fluoride fine particles is 0.01 per 100 parts by weight of the magnetic toner.
The electrophotographic method is characterized by using a magnetic toner of about 3.0 parts by weight.

Further, the present invention is an electrophotographic method characterized by using a magnetic toner having a specific surface area of polyvinylidene fluoride fine particles of 2.0 to 25.0 m ² / g.

Further, the present invention is an electrophotographic method characterized by using a magnetic toner having a volume average particle diameter of polyvinylidene fluoride fine particles of 3 to 20 μm.

Further, the present invention is an electrophotographic method characterized in that a magnetic toner produced by emulsion polymerization of polyvinylidene fluoride fine particles is used.

Further, the present invention is an electrophotographic method characterized by using a one-component toner.

[0038]

By using the organic photoreceptor and the magnetic toner of the present invention, the following effects can be obtained for toner filming.

The external additive used in the magnetic toner according to the present invention is obtained by surface-treating hydrophobic silica fine particles obtained by treating silicon tetrachloride with silicone oil. The surface treatment of the silica fine particles can be performed by a known method such as a mixing method or an injection method.

The organic photoreceptor used in the present invention comprises a conductive support, such as aluminum, on which a charge generating layer having a charge generating substance dispersed in a binder resin is formed. Further, a polycarbonate resin is used as the photosensitive resin and at least silicone oil is used. It is formed by sequentially stacking 0.01 to 3.0 parts by weight and a charge transport layer containing a charge transport material. The polycarbonate resin used as the photoreceptor resin contains one or more repeating units represented by the general formula (Formula 3) as a component.

[0041]

Embedded image

A magnetic toner using silica fine particles hydrophobized with silicone oil as an external additive as in the present invention,
It has been found that a combination with a photoreceptor containing a polycarbonate resin having silicone oil added to the surface layer is an effective means for preventing toner filming. This is because the adhesive force between the silica particles and the photoconductor is reduced by the photoconductor having the silica fine particles hydrophobized with silicone oil and the polycarbonate resin to which the silicone oil is added, and the silica fine particles adhering to the photoconductor are removed by the cleaning blade. Therefore, it is considered that the silica fine particles can be prevented from being embedded in the photoconductor, which is effective for toner filming.

Further, polyvinylidene fluoride fine particles are used as an external additive used for the magnetic toner according to the present invention.

This is because an effective effect on toner filming can be obtained by using a photoreceptor having silica fine particles hydrophobized with silicone oil and a polycarbonate resin containing silicone oil in the surface layer, especially at low temperature and low humidity. Below, the impact resilience of the cleaning blade such as urethane rubber becomes small, the frictional resistance between the cleaning blade and the photoconductor becomes large, and silica fine particles cannot be removed and are buried in the photoconductor surface. As a result, toner filming occurs.

To solve this problem, when the magnetic toner of the present invention to which the fine particles of polyvinylidene fluoride are externally added is used, the fine particles of polyvinylidene fluoride having a lubricating function are accumulated at the tip of the cleaning blade and are exposed to light even at low temperature and low humidity. The frictional resistance between the body and the cleaning blade can be kept low. Therefore, the silica fine particles can be easily removed from the surface of the photoconductor and the burial of the silica fine particles on the surface of the photoconductor can be prevented, so that the effect on the toner filming problem under low temperature and low humidity is dramatically increased.

Further, as in the electrophotographic method of the present invention, a magnetic toner using silica fine particles hydrophobized with silicone oil as an external additive, and a photoreceptor containing a polycarbonate resin with silicone oil added to the surface layer. The combination has been found to be an effective means of preventing toner filming. This is because the adhesive force between the silica particles and the photoconductor is reduced by the photoconductor having the silica fine particles hydrophobized with silicone oil and the polycarbonate resin to which the silicone oil is added, and the silica fine particles adhering to the photoconductor are removed by the cleaning blade. Becomes easier,
It is considered that the silica fine particles can be prevented from being buried in the photoconductor, which is effective for toner filming.

Further, fine particles of polyvinylidene fluoride are used as an external additive for the magnetic toner used in the electrophotographic method according to the present invention.

This is because an effective effect on toner filming can be obtained by using a photoreceptor having a surface layer of silica fine particles hydrophobized with silicone oil and a polycarbonate resin added with silicone oil, especially at low temperature and low humidity. Below, the impact resilience of the cleaning blade such as urethane rubber becomes small, the frictional resistance between the cleaning blade and the photoconductor becomes large, and silica fine particles cannot be removed and are buried in the photoconductor surface. As a result, toner filming occurs.

To solve this problem, when the magnetic toner of the present invention to which the polyvinylidene fluoride fine particles are externally added is used, the polyvinylidene fluoride fine particles having a lubricating function are accumulated at the tip of the cleaning blade and are exposed to light even at low temperature and low humidity. The frictional resistance between the body and the cleaning blade can be kept low. Therefore, the silica fine particles can be easily removed from the surface of the photoconductor and the burial of the silica fine particles on the surface of the photoconductor can be prevented, so that the effect on the toner filming problem under low temperature and low humidity is dramatically increased.

Further, in the electrophotographic method of the present invention, the releasability of silicone oil is improved by the constitution comprising a magnetic toner externally added with silica fine particles hydrophobized with silicone oil and a photoreceptor containing silicone resin added to polycarbonate resin. Due to the high characteristics, the adhesive force between the magnetic toner and the photoreceptor is reduced. This facilitates the recovery of toner in the non-image area, and is considered to be effective against fogging.

Further, in the electrophotographic method of the present invention, a magnetic toner to which polyvinylidene fluoride fine particles are externally added is used.

This is composed of fine silica particles hydrophobized with silicone oil and a photoreceptor obtained by adding silicone oil to a polycarbonate resin.
This is an effective means, but when moisture is adsorbed on the surface of the photoconductor particularly under high temperature and high humidity, the adhesive force between the magnetic toner and the photoconductor is increased and fogging occurs. Therefore, when the polyvinylidene fluoride fine particles having high releasability are added, the adhesive force between the photoreceptor and the toner becomes low, and fogging does not occur even under high temperature and high humidity.

Further, in the magnetic toner and electrophotographic method according to the present invention, if the addition amount of the silica fine particles is 0.1 parts by weight or less based on 100 parts by weight of the toner, the fluidity of the toner cannot be obtained. The toner supply amount is reduced and the image density is lowered. Further, the intermolecular force between the photoconductor and the toner becomes large, and the toner adheres to the non-image portion. Further, when the amount of silica fine particles added is 5.0 parts by weight or more, the amount of floating silica fine particles increases and white spots appear on the image.

Further, in the magnetic toner and electrophotographic method according to the present invention, these effects cannot be obtained if the amount of polytetrafluoroethylene fine particles added is 0.01 parts by weight or less based on 100 parts by weight of the toner. When the amount is 3.0 parts by weight or more, uniform mixing with the toner cannot be performed and an image defect appears as a white spot on the image.

In the magnetic toner and electrophotographic method according to the present invention, these effects cannot be obtained if the amount of silicone oil added to the polycarbonate in the photoconductor charge transport layer is 0.1 parts by weight or less. If the amount exceeds 3 parts by weight, the electrostatic characteristics of the surface of the photoreceptor deteriorate, the residual potential during exposure rises at low temperature and low humidity, and the image density decreases.

In the magnetic toner and electrophotographic method according to the present invention, the silica fine particles have a specific surface area of 50 to 300 m.
² / g is preferable. When the specific surface area is 50 m ² / g or less, the particle size becomes large, the function of the fluidity improver is lost, and high fluidity cannot be obtained. Also, the specific surface area is 300m
^{When it is 2} / g or more, the particle size becomes small, a thin layer of silica fine particles is formed on the OPC surface in order to slip through the cleaning blade, the residual potential during exposure rises, and the image density decreases during reversal development. However, during regular development, fogging occurs in the non-image area on the image.

In the magnetic toner and the electrophotographic method according to the present invention, it is desirable that the polyvinylidene fluoride fine particles have a specific surface area of ² to 25 m ² / g and a volume average diameter of 3 to 25 μm and are prepared by emulsion polymerization. . Since the fine particles formed by suspension polymerization have a spherical shape, a thin layer of polyvinylidene fluoride fine particles is formed on the OPC surface in order to slip through the cleaning blade, the residual potential during exposure rises, and during reverse development. As a result, the image density is reduced, and fog occurs in the non-image area on the image during regular development. This has a volume average diameter of 3 μm or less and a specific surface area of 2
The same phenomenon occurs when it is 5 m ² / g or more. On the other hand, if the volume average particle size is 20 μm or more, the volume average particle size becomes larger than the volume average particle size of the toner particles, and uniform mixing with the toner cannot be performed. Further, when the specific surface area is 2.0 m ² / g or less, the volume average particle diameter becomes large as a result, and the shape becomes spherical and the effect cannot be obtained.

In the magnetic toner and electrophotographic method according to the present invention, the insulating one-component toner is particularly preferable. When the one-component toner is used, the agitating mechanism for the carrier and the toner, which is necessary for the two-component development, and the toner concentration control are unnecessary, and therefore the apparatus configuration can be simplified.

[0059]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic toner and an electrophotographic method according to an embodiment of the present invention will be described below with reference to the drawings. The present invention is not limited to this.

(Embodiment 1) FIG. 1 shows an embodiment of the electrophotographic method of the present invention. The developing method is a one-component developing method. Reference numeral 1 denotes an organic photoreceptor, which is a polyvinyl butyral resin (Elec BL-1 manufactured by Sekisui Chemical Co., Ltd.) and a charge generation layer in which a charge generation substance of τ-type metal-free phthalocyanine (manufactured by Toyo Ink) is dispersed on a conductive support made of aluminum and a polycarbonate. Charge transfer agent 1,1-bisP-diethylaminophenyl-1,3-butadiene (T-405 manufactured by Anan Co., Ltd.) and silicone oil TSF451-100 manufactured by Toshiba Silicon are dispersed in a resin (Z-200 manufactured by Mitsubishi Chemical). The charge transport layer is sequentially laminated. 2 is a non-rotating magnet that is fixed coaxially with the photoconductor 1; 3 is a corona charger that negatively charges the photoconductor; 4 is a grid electrode that controls the charging potential of the photoconductor; 5 is signal light; The developing device for visualizing the image is a magnetic one-component toner 7; a toner hopper 6 for supplying the magnetic toner 7 to the surface of the photoconductor 1; A magnetic electrode roller, 9 is a non-rotating magnet installed inside the electrode roller 8, 10 is an AC high voltage power source for applying a voltage to the electrode roller 8, 11 is a scraper made of phosphor bronze for scraping off toner on the electrode roller, 12 Is a transfer corona charger that transfers the toner image on the photoreceptor to paper. Numeral 13 is a damper for smoothing the flow of toner in the toner reservoir and for preventing the toner from being crushed by its own weight and clogged between the photoconductor and the electrode roller.

The magnetic flux density on the surface of the photoconductor 1 is 600 Gs. The magnetic force inside the electrode roller was strengthened to improve transportability. Further, the magnetic pole angle θ of the magnet 2 shown in the figure was set to 15 degrees. The photoconductor 1 has a diameter of 30 mm and a peripheral speed of 40 m.
It was rotated at m / s in the direction of the arrow in the figure and used. The electrode roller 8 had a diameter of 16 mm, and was rotated at a peripheral speed of 40 mm / s in the direction opposite to the traveling direction of the photoconductor (the direction of the arrow in the figure). The gap between the photoconductor 1 and the electrode roller 8 is 200 μm
Set to.

The photosensitive member 1 is connected to the corona charger 3 (applied voltage-
4.5kV, voltage of grid 4 -500V), -50
It was charged to 0V. The photoconductor 1 was irradiated with laser light 5 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor is -9.
It was 0V. Toner 7 was attached to the surface of the photoreceptor 1 in the toner reservoir 6 by a magnet. Next, the photoconductor 1 was passed in front of the electrode roller 8. When passing through the uncharged area of the photoconductor 1, the AC high voltage power supply 10 is applied to the electrode roller 8
AC voltage of 750V _0-p (peak-to-peak 1.5kV) superposed with 0V DC voltage (frequency 1kHz)
Was applied. After that, when the photoconductor 1 charged with −500V and having an electrostatic latent image written thereon is passed, the electrode roller 8 is superposed with a DC voltage of −350V by the AC high voltage power source 750V 0-p (peak-to-peak). 1.5k
V) (frequency 1 kHz). Then, the toner adhering to the charged portion of the photoconductor 1 was collected by the electrode roller 8, and a negative-positive-reversed toner image remained only on the image portion on the photoconductor 1. The toner attached to the electrode roller 8 rotating in the direction of the arrow is scraped off by the scraper 11,
It was returned to the toner hopper 6 again and used for the next image formation. The toner image thus obtained on the photoconductor 1 is transferred onto a transfer paper by a transfer charger 12, and then a fixing device (not shown).
By this, heat fixing is performed to obtain a copied image.

The binder resin of the magnetic toner according to the present invention is a vinyl polymer obtained by polymerizing or copolymerizing vinyl monomers. Examples of the monomer styrene constituting the binder resin include styrene such as styrene, α-methylstyrene, p-chlorostyrene and its substitution products, and examples of the acrylic acid alkyl ester include acrylic acid, methyl acrylate, and acrylic acid. Ethyl acid, butyl acrylate, dodecyl acrylate, octyl acrylate, isobutyl acrylate, hexyl acrylate, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, isobutyl methacrylate, There are monocarboxylic acids having a double bond such as dodecyl methacrylate and hexyl methacrylate, and substituted products thereof.

As a method for producing these copolymers, known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization are adopted.

The copolymer used in the magnetic toner according to the present invention preferably contains 50 to 95% by weight as a styrene component. When the proportion of the styrene component is less than 50% by weight, the melting property of the toner is inferior, the fixing property is insufficient, and the pulverizability is deteriorated.

The magnetic toner according to the present invention contains the binder resin as a main component as described above, but other known polymers or copolymers may be used as required in addition to the main components. . For example, there are polyester resin, epoxy resin, polyurethane resin, and the like.

Further, the magnetic toner according to the present invention may be blended with an appropriate pigment or dye for the purpose of controlling coloring and charge, if necessary. Examples of such pigments or dyes include carbon black, iron black, graphite, nigrosine, metal complexes of azo dyes, phthalocyanine blue, DuPont oil red, aniline blue, benzidine yellow, rose bengal, and mixtures thereof, etc., and charge amount, The amount required for coloring is blended.

Further, in the magnetic toner according to the present invention, polyethylene, polypropylene, carnauba wax, amide wax, etc. are blended as a release agent, if necessary.

The magnetic toner used in the present invention contains a magnetic substance. Examples of the magnetic powder include metal powder such as iron, manganese, nickel and cobalt, and ferrite such as iron, manganese, nickel, cobalt and zinc. An oxide magnetic material is particularly preferable, and an iron-based ferrite magnetite is preferable. The average particle diameter of the magnetic powder is preferably 1 μm or less, particularly preferably 0.6 μm or less.

The specific surface area is measured by the usual BET method, using FlowSorb2-2300 manufactured by Shimadzu Corporation,
Four points were measured and calculated by extrapolation. Using a mixed gas of nitrogen / helium, the mixing ratio of each is 5.0 and the nitrogen concentration is 1.
Those having a content of 2.0, 18.0, 24, 0% by weight were used.

The volume average diameter was 50% of the volume distribution using a Coulter Counter TA-2 manufactured by Nikkaki Co., Ltd.

The composition of the charge transport layer of the photoreceptor used in Example 1 is shown in (Table 1). The photoreceptor binder resin is a polycarbonate resin (Z-200 manufactured by Mitsubishi Chemical), the charge transport agent is 1,1-bisP-diethylaminophenyl-1,3-butadiene (T-405 manufactured by Anan Co.), and further additives. Silicone oil as (TSF451 manufactured by Toshiba Silicone
-100) was used. Photosensitive members were prepared by changing the amount of silicone oil added. Table 1 shows the composition of the charge transport layer of the photoconductor.

[0073]

[Table 1]

Next, the material composition of the magnetic toner used in Example 1 is shown in (Table 2).

[0075]

[Table 2]

The magnetic toner according to the present invention is manufactured by the following method. The toner is mixed, kneaded, pulverized, externally added, and if necessary classified. Also, other methods such as a polymerization method may be used.

The mixing treatment is a treatment in which a binder resin, a magnetic material and other internal additives such as a charge control agent, a release agent and a pigment, which are added as necessary, are uniformly dispersed by a mixer equipped with stirring blades. A known processing method is used.

In the kneading process, the mixed material is heated to disperse the internal additive in the binder resin by shearing force. The kneading treatment at this time can be performed using a known heating kneader. As a heating and kneading machine, three roll type,
A device for heating a kneaded material such as a single screw type, a twin screw type, a Banbury mixer type, and applying a shearing force can be used. The mass obtained by the kneading process is roughly crushed with a cutter mill or the like. In the crushing process, it is crushed finely with a jet mill crusher. Further, if necessary, in the classification treatment, fine powder particles are cut by an airflow classifier to obtain a desired particle size distribution. At this time, mechanical crushing and classification are also possible. For example, there is a method in which toner is charged into a minute gap between a fixed stator and a rotating rotor and then pulverized. There is also a method of classifying by centrifugal force using a rotating rotor even in classification. Known methods are used in both cases.

In the external additive treatment, an external additive is mixed with the magnetic toner and the additive is externally treated by a known mixer or the like.

The production of the magnetic toner of the present invention will be specifically described. The mixture shown in (Table 2) is mixed with a Henschel mixer FM20B (manufactured by Mitsui Miike Co., Ltd.). The mixture is heated and kneaded with a twin-screw kneading extruder PCM30 (manufactured by Ikegai Tekko KK). Finely pulverized with a jet mill crusher IDS2 type (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) and cut fine powder by an air flow classifier DS2 type (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and a toner having a volume average particle diameter of 8.0 μm. -The mother is obtained. After that, external additives shown in (Table 3) were externally added to the toner base to prepare a magnetic toner. The external addition treatment was performed using a Henschel mixer FM20B (manufactured by Mitsui Miike Co., Ltd.).

[0081]

[Table 3]

Silica A1 (TS720 manufactured by CABOT) was used as the silica fine particles hydrophobized with silicone oil. Silica B1 is silica fine particles hydrophobically treated with dimethyldichlorosilane (R97 manufactured by Nippon Aerosil Co., Ltd.).
4), silica B2 is silica treated with hexamethyldisilazane (TS530 manufactured by CABOT). Further, polyvinylidene fluoride fine particles A (Fluon 173J manufactured by Asahi Glass Co., Ltd.) was used as an external additive.

Next, the electrophotographic method and photoreceptor A shown in FIG.
Using toner A, a long-term copying test of 10,000 sheets was performed under low temperature and low humidity (7 ° C. 20%), normal temperature and normal humidity (20 ° C. 50%), and high temperature and high humidity (35 ° C. 85%). As a result, in any environment, the image density was 1.4 or more from the initial stage to 10,000 sheets, the horizontal line was not disturbed, the toner was not scattered, and the solid was uniform, and the background fog was 5 toner / mm.
^When the image density was ² or less, an extremely high resolution and high quality image in which 16 lines / mm of image lines having an image density of 1.4 were reproduced was obtained. The image density was measured using a reflection densitometer (Macbeth).

Example 2 A toner was prepared in the same manner as the toner A of Example 1 except that the polyvinylidene fluoride fine particles were KYNAR461 (manufactured by Mitsubishi Yuka).

Next, using this toner, the electrophotographic method shown in FIG. 1, and the photoconductor A, a low temperature and low humidity (7 ° C. 20%), a room temperature and normal humidity (20 ° C. 50%), and a high temperature and high humidity (35%) were used. ℃ 85%)
A long-term copy test of 10,000 sheets was conducted. as a result,
Under any environment, the image density is 1.4 or more from the initial stage to 10,000 sheets, the solid is uniform without the disturbance of horizontal lines and the scattering of toner, and the background fog is 5 toner / m.
At m ² or less, an extremely high resolution and high quality image in which 16 lines / mm of image lines having an image density of 1.4 were reproduced was obtained.

Example 3 A toner was prepared in the same manner as the toner A of Example 1 except that the addition amount of the polyvinylidene fluoride fine particles was 0.01 part by weight with respect to 100 parts by weight of the toner.

Next, using this toner, the electrophotographic method shown in FIG. 1, and the photoconductor A, a low temperature and low humidity (7 ° C. 20%), a room temperature and normal humidity (20 ° C. 50%) and a high temperature and high humidity (35%) were used. ℃ 85%)
A long-term copy test of 10,000 sheets was conducted. as a result,
Under any environment, the image density is 1.4 or more from the initial stage to 10,000 sheets, the solid is uniform without the disturbance of horizontal lines and the scattering of toner, and the background fog is 5 toner / m.
At m ² or less, an extremely high resolution and high quality image in which 16 lines / mm of image lines having an image density of 1.4 were reproduced was obtained.

Example 4 A toner was prepared in the same manner as Toner A in Example 1 except that the amount of polyvinylidene fluoride fine particles added was 3.0 parts by weight based on 100 parts by weight of the toner.

Next, using this toner, the electrophotographic method shown in FIG. 1, and the photoconductor A, a low temperature and low humidity (7 ° C. 20%), a room temperature and normal humidity (20 ° C. 50%) and a high temperature and high humidity (35%) were used. ℃ 85%)
A long-term copy test of 10,000 sheets was conducted. as a result,
Under any environment, the image density is 1.4 or more from the initial stage to 10,000 sheets, the solid is uniform without the disturbance of horizontal lines and the scattering of toner, and the background fog is 5 toner / m.
At m ² or less, an extremely high resolution and high quality image in which 16 lines / mm of image lines having an image density of 1.4 were reproduced was obtained.

Comparative Example 1 A copying test was conducted by using the electrophotographic method shown in Example 1 and using the photoconductor B1 shown in (Table 1). When a copy test was performed under low temperature and low humidity, it was 7
Toner filming occurs at 00 sheets and the image density is 1.1.
And it became a low-quality image.

(Comparative Example 2) A copying test was conducted by using the electrophotographic method shown in Example 1 and using the photoconductor B2 shown in (Table 1). When a copy test was performed on the exposure potential under low temperature and low humidity, the residual potential at the time of exposure increased to 350 V, and the image density was 1.0 and the image was low in quality.

Comparative Example 3 Using the electrophotographic method shown in Example 1, a copying test was conducted using Toner B1 shown in (Table 3). When a copy test was performed under low temperature and low humidity, it was 7
Toner filming occurs at 00 sheets and the image density is 1.2.
And it became a low-quality image.

Comparative Example 4 A copying test was conducted using the toner B2 shown in (Table 3) by using the electrophotographic method shown in Example 1. When a copy test was performed under low temperature and low humidity, 2
Toner filming occurs at 00 sheets and the image density is 1.0
And became a low quality image.

(Comparative Example 5) Using the electrophotographic method shown in Example 1, a copying test was conducted using Toner B3 shown in (Table 3). When a copy test was performed under low temperature and low humidity, 2
Toner filming occurs at 00 sheets and the image density is 1.0
And it became a low-quality image.

(Comparative Example 6) The addition amount of silica fine particles was adjusted to 0.
A toner prototype was prepared with the same composition as the toner A of Example 1 except that the amount was changed to 05 parts by weight. The fluidity of the toner was low, and when a copy test was performed, the image density was 0.6 and the image was extremely low-quality.

(Comparative Example 7) The amount of silica fine particles added was 8.
A toner prototype was prepared with the same composition as the toner A of Example 1 except that the amount was 0 parts by weight. Aggregates of silica fine particles were conspicuous in the toner, and when a copy test was conducted, white spots of the silica fine particles were present on the solid image, resulting in an extremely low-quality image.

Comparative Example 8 A toner prototype was prepared with the same composition as the toner A of Example 1 except that the addition amount of the polyvinylidene fluoride fine particles was 8.0 parts by weight. Aggregates of polyvinylidene fluoride fine particles were conspicuous in the toner, and when a copy test was conducted, white spots of silica fine particles were present on the solid image, resulting in an extremely low-quality image.

(Comparative Example 9) The addition amount of the magnetic material was 10% by weight.
A toner trial was prepared with the same composition as the toner A of Example 1 except for the above. A large amount of toner was scattered and the background fog in the non-image area was large, and a practical image could not be obtained.

(Comparative Example 10) A toner prototype was prepared with the same composition as the toner A of Example 1 except that the addition amount of the magnetic material was 80% by weight. The amount of charge was low and the background fog in the non-image area was large, and a practical image could not be obtained.

(Comparative Example 11) A toner trial was prepared with the same composition as the toner A of Example 1 except that silica fine particles having a specific surface area of 20 m ² / g were used. Since the fluidity was low and the background fog in the non-image area was large, a practical image could not be obtained.

(Comparative Example 12) Specific surface area of 400 m ² / g
A toner trial was prepared with the same composition as the toner A of Example 1 except that the above silica fine particles were used. Since the silica fine particles are strongly aggregated and cannot be uniformly mixed with the toner, aggregates of the silica fine particles are conspicuous in the toner, and when a copy test is carried out, white spots of the silica fine particles are present on the solid image, resulting in extremely low quality. It became an image.

(Comparative Example 13) A specific surface area of 30.0 m ² /
A toner prototype was prepared with the same composition as the toner A of Example 1 except for the polyvinylidene fluoride fine particles of g. The fine particles of polyvinylidene fluoride slipped through the cleaning blade, the fine particles of polyvinylidene fluoride adhered to the photoconductor, the residual potential at the time of exposure increased, and the image density decreased to 0.7.

(Comparative Example 14) Specific surface area of 1.5 m ² / g
A toner prototype was prepared with the same composition as the toner A of Example 1 except for the above polyvinylidene fluoride fine particles. Since the particle size of the fine particles became large and the particles could not be mixed uniformly with the toner, a copy test was carried out, and there were many white spots on the image, resulting in an extremely low-quality image.

[0104]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, an organic photoconductor in which a polycarbonate resin and silicone oil are internally added to a charge transport layer, and silica fine particles and polyvinylidene fluoride fine particles which are hydrophobized with silicone oil are externally added. A magnetic toner composed of an agent and a fixed magnet, and a movable photoconductor, a toner hopper, and a toner collecting electrode roller having a magnet inside at a position having a predetermined gap from the surface of the photoconductor. After the electrostatic latent image is formed on the photoconductor, magnetic toner is magnetically attracted to the surface of the photoconductor located in the toner hopper, the magnetic toner is carried on the surface of the photoconductor, and the photoconductor is moved. The electrophotographic method has a developing process in which the toner is left in the image portion of the photoconductor while the toner in the non-image portion is opposed to the toner collecting electrode roller and the toner in the non-image portion is collected by the toner collecting electrode roller. In an electrophotographic method using a magnetic toner comprising an organic photoconductor in which a polycarbonate resin and silicone oil are internally added to a charge transport layer, and an external additive of silica fine particles and polyvinylidene fluoride fine particles that have been hydrophobicized with silicone oil. By a certain configuration, it is possible to reduce the adhesive force between the photoconductor and the silica fine particles, and by adding polyvinylidene fluoride fine particles to the magnetic toner,
As cleaning performance can be improved, toner
A magnetic toner that does not cause filming can be realized. Further, in an electrophotographic method capable of downsizing, simplification, and cost reduction of the apparatus, toner filming can be prevented even during long-term running under low temperature and low humidity, and image density is high even under high temperature and high humidity. It is possible to realize an electrophotographic method of a few high-quality images.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an electrophotographic apparatus used in an electrophotographic method of the present invention.

[Explanation of symbols]

 1 Electrostatic Latent Image Holder Drum 2 Fixed Magnet 6 Enclosed in the Electrostatic Latent Image Holder 6 Toner Reservoir 7 Magnetic Toner 8 Electrode Roller 9 Magnet Installed Inside Electrode Roller 12 Transfer Corona Charger

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location G03G 5/147 502 504 15/08 507 B G03G 9/08 375 (72) Inventor Noriaki Hirota Osaka Prefecture 1006 Kadoma, Kadoma-shi, Matsushita Electric Industrial Co., Ltd. (72) Hideki Tatematsu, 1006 Kadoma, Kadoma-shi, Osaka Prefecture (72) In Matsushita Electric Industrial Co., Ltd. No. 8 Matsushita Electric Transmission Co., Ltd.

Claims (22)

[Claims] 1. An electrostatic latent image carrier is an organic photoreceptor containing at least a polycarbonate resin, an organic photoconductive substance and an additive represented by the general formula (Chemical Formula 1) in a surface layer, and a magnetic toner is at least A binder resin, a magnetic substance, and an external additive, wherein the external additive is at least hydrophobic silicon dioxide particles surface-treated with a treating agent represented by the general formula (Formula 1),
A magnetic toner comprising fine particles represented by the general formula (Formula 2). Embedded image Embedded image 2. The organic photoconductor according to claim 1, wherein the electrostatic latent image carrier is an organic photoconductor formed by sequentially stacking a charge generation layer and a charge transport layer on a conductive support. Magnetic toner. 3. The additive represented by the general formula (Formula 1) added to the electrostatic latent image carrier is 0.01 to 3.0 parts by weight based on 100 parts by weight of the charge transport layer. The magnetic toner according to claim 1, wherein the magnetic toner is a magnetic toner. 4. The amount of magnetic material added is based on the weight of magnetic toner.
The magnetic toner according to claim 1, which is 15 to 70% by weight. 5. The magnetic toner according to claim 1, wherein the addition amount of the hydrophobic silicon dioxide fine particles is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the magnetic toner. 6. The hydrophobic silicon dioxide fine particles have a specific surface area of 50.
The magnetic toner according to claim 1, wherein the magnetic toner has a density of about 300 m ² / g. 7. The magnetic toner according to claim 1, wherein the amount of the fine particles represented by the general formula (Formula 2) is 0.01 to 3.0 parts by weight with respect to 100 parts by weight of the magnetic toner. . 8. The specific surface area of the fine particles represented by the general formula (Formula 2) is ² to 25 m ² / g.
The magnetic toner described. 9. The volume average particle size of the fine particles represented by the general formula (Formula 2) is 3 to 20 μm.
The magnetic toner described. 10. The magnetic toner according to claim 1, wherein the fine particles represented by the general formula (Formula 2) are produced by emulsion polymerization. 11. The magnetic toner according to claim 1, which is a one-component toner. 12. A movable electrostatic latent image holding member including a fixed magnet, a toner hopper, and a magnet inside at a position having a predetermined gap from the surface of the electrostatic latent image holding member. A toner recovery electrode roller is provided, and after forming an electrostatic latent image on the electrostatic latent image holder, magnetic toner is magnetically attracted to the surface of the electrostatic latent image holder located in the toner hopper. Then, the magnetic toner is carried on the surface of the electrostatic latent image holding member, the electrostatic latent image holding member is moved to face the toner collecting electrode roller, and the image portion of the electrostatic latent image holding member is moved. An electrophotographic method having a developing step in which toner is left and toner in the non-image area is collected by the toner collecting electrode roller, wherein the electrostatic latent image holding member has at least a polycarbonate resin and an organic photoconductive material as a surface layer. And an additive represented by the general formula (Formula 1) An organic photoreceptor containing, and the magnetic toner is composed of at least a binder resin, a magnetic body and an external additive,
The external additive is a magnetic toner composed of at least hydrophobic silicon dioxide fine particles surface-treated with a treating agent represented by the general formula (Formula 1) and fine particles represented by the general formula (Formula 2). The method of electrophotography. 13. The organic photoconductor according to claim 12, wherein the electrostatic latent image carrier is an organic photoconductor formed by sequentially laminating a charge generation layer and a charge transport layer on a conductive support. Electrophotographic method. 14. The content of the additive represented by the general formula (Formula 1) added to the electrostatic latent image carrier is 0.01 to 3.0 parts by weight with respect to 100 parts by weight of the charge transport layer. 13. The electrophotographic method according to claim 12, wherein: 15. The electrophotographic method according to claim 12, wherein the magnetic toner is used in an amount of 15 to 70% by weight based on the weight of the magnetic toner. 16. The electrophotographic method according to claim 12, wherein the amount of the hydrophobic silicon dioxide fine particles added is 0.1 to 5.0 parts by weight based on 100 parts by weight of the magnetic toner. . 17. The hydrophobic silicon dioxide fine particles have a specific surface area of 5
The electrophotographic method according to claim 12, wherein a magnetic toner having a weight of 0 to 300 m ² / g is used. 18. The addition amount of the fine particles represented by the general formula (Formula 2) is 0.01 to 3.0 with respect to 100 parts by weight of the magnetic toner.
13. The electrophotographic method according to claim 12, wherein the magnetic toner is used in an amount of part by weight. 19. The electrophotographic method according to claim 12, wherein a magnetic toner in which the specific surface area of the fine particles represented by the general formula (Formula 2) is ² to 25 m ² / g is used. 20. The electrophotographic method according to claim 12, wherein a magnetic toner in which the volume average particle diameter of the fine particles represented by the general formula (Formula 2) is 3 to 20 μm is used. 21. The electrophotographic method according to claim 12, wherein the fine particles represented by the general formula (Formula 2) are magnetic toners produced by emulsion polymerization. 22. The electrophotographic method according to claim 12, wherein the magnetic toner is a one-component toner.