JPH06324512A - Developer and image formation - Google Patents

Abstract

PURPOSE:To exert an excellent transfer characteristic in the high-temperature, high-humidity environment by using a fluorine containing polymerization compound polymer having a cross-linking structure for organic fine grains. CONSTITUTION:A single polymer or a copolymer of a fluorine containing polymerization compound having a cross-linking structure and the fluorine group for the principal chain is used for the organic fine grains of a developer. The organic fine grains have the primary average grain size of 50-500mum and the BET specific surface area of 10-120m<2>/g'. A developer conveying carrier 20 is constituted of a magnet roll 21 having eight magnetic N/S poles in turn rotated in the arrow direction and a developing sleeve 22 rotated in the opposite direction to the magnet roll 21 and conveying a developer layer to a development area K. The gap between a photoreceptor 14 rotated in the arrow direction and the developing sleeve 22 is normally set to 100-1000mum, larger than the thickness of the developer layer, thus allowing noncontact development in the vibrating electric field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer containing a toner containing colored particles and organic fine particles, and a developer carrying carrier carries a latent image on a developer layer composed of a two-component developer. A step of developing the electrostatic latent image on the latent image carrier under an oscillating electric field obtained by carrying the developer carrying carrier in a non-contact state with the body and applying an AC bias voltage to the developer carrying carrier. And an image forming method including the following.

[0002]

2. Description of the Related Art A typical example of an electrophotographic method will be described. An electrostatic latent image is formed on a photoconductive photosensitive member by charging and exposure, and the electrostatic latent image is developed by a developer to form a toner. An image is formed and then this toner image is transferred to a transfer material and fixed to form a copied image.

The image forming process by the electrophotography as described above has the following problems.

(1) Environmental Dependence of Transfer Characteristics In the transfer step of the image forming process, the transfer characteristics tend to largely depend on the environment. In particular, when the image is formed in a high temperature and high humidity environment, the transfer rate to the transfer material is lower than that in the normal temperature and normal humidity environment, and transfer unevenness may occur in the obtained copy image. Yes, sufficient transcription characteristics are not expressed.

This is because under a high temperature and high humidity environment, the charge amount of the toner, which has a great influence on the transfer characteristics, is not sufficient, and the water content of the transfer material is absorbed and dew condensation occurs on the surface of the transfer material. This is because it is easy and the surface electric resistance of the transfer material is extremely reduced.

(2) Environmental Dependence of Image Density The image density of a copy image to be formed tends to largely depend on the environment, and in particular, the humidity environment (water content in the air) has a great influence on the image density.

For example, when a halftone gray chart copy image is formed in a high temperature and high humidity environment, the image density of the obtained copy image is higher than the original density, and the faithful image density cannot be reproduced. This is because in a high temperature and high humidity environment, the amount of charge is reduced, resulting in excessive development.

On the other hand, from the viewpoints of improving the chargeability of the toner, environmental stability of the charge amount, etc., a technique of incorporating fluororesin particles into the toner has been introduced (Japanese Patent Laid-Open No. 53-1300).
36, JP-A-62-75539, JP-A-6
2-75553, JP-A-3-170946, etc.).

According to these techniques, the hydrophobic fluororesin particles can stabilize the amount of charge in the environment, and can solve the problems (1) and (2) to some extent.

However, the fluororesin particles used in the techniques described in the above publications are all composed of a non-crosslinked structure homopolymer or copolymer, and the fluororesin composed of such a (co) polymer. The particles are very soft and easily deformed. Therefore, when a toner containing such a fluororesin particle is used and an image is repeatedly formed by a copying machine equipped with a toner recycling system or the like, the fluororesin particle adheres to and fuses with a developing sleeve or a carrier. Pollutes the
It may cause white stripes on the formed copy image or may cause internal contamination due to toner scattering.

As described above, in the technique described in the above publication, the durability as a developer is poor and it is impossible to stably form a copy image many times.

(3) Adhesion of Carrier When the toner in the developer layer is caused to fly from the surface of the developer carrier to the surface of the photoconductor in the non-contact developing method, the carrier moves together with the toner onto the photoconductor. There is a problem (carrier adhesion).

The carrier transferred onto the photoreceptor is
In the transfer process, a pressure is applied between the surface of the photoconductor and the transfer material, which hinders the transfer of toner in the vicinity of the transfer material, causing an image defect such that a solid image becomes white. Further, the carrier on the photoconductor may directly stain the image to cause a defective image.

Particularly recently, a carrier having a low magnetization and a small particle size is used from the viewpoint of improving the developability, and
Toners having a small particle size have been used from the viewpoint of improving the reproducibility of fine lines. When a developer made of such carrier or toner is used, the problem of carrier adhesion is particularly likely to occur.

In order to solve the problem of carrier adhesion,
It is necessary to reduce the adhesive force between the toner and the carrier.
However, since the non-crosslinked fluororesin particles are very soft and easily deformed, the contact area between the toner and the carrier is substantially increased by the deformed fluororesin particles,
As a result, the physical adhesive force between the two is increased (increase in frictional force).

On the other hand, the charge amount of the toner in the two-component developer is a physical amount due to the interaction between the toner and the carrier. Therefore, even if the hydrophobic resin is introduced only in the toner of the two-component developer, the environmental stability of the image density cannot be sufficiently achieved.

[0017]

The present invention has been made under the circumstances described above, and the first object of the present invention is to provide an image in a high temperature and high humidity environment. It is an object of the present invention to provide a developer having excellent durability that can exhibit excellent transfer characteristics and can stably form a copy image many times. A second object of the present invention is to provide a developer which is excellent in environmental stability of image density (reproduction stability of density) and which can reproduce faithful image density even in a high temperature and high humidity environment. It is in.

A third object of the present invention is to exhibit good transfer characteristics even in a high temperature and high humidity environment, without causing a problem of image defects due to carrier adhesion, and in copying many times. An object of the present invention is to provide an image forming method capable of stably forming an image. A fourth object of the present invention is to provide an image forming method which is excellent in environmental stability of image density (reproduction stability of density) and which can reproduce faithful image density even in a high temperature and high humidity environment. Especially.

[0019]

The developer of the present invention is a developer containing a toner containing colored particles and organic fine particles, wherein the organic fine particles have a crosslinked structure and fluorine of the main chain. It is characterized by being a homopolymer or copolymer of a fluorine-containing polymerizable compound having a group (hereinafter also referred to as "fluorine-containing polymerizable compound (co) polymer").

Further, in the developer of the present invention, it is preferable that the organic fine particles have a primary average particle diameter of 50 to 500 nm and the BET specific surface area thereof is 10 to 120 m ² / g.

Further, the developer of the present invention preferably contains a resin-coated carrier in which a resin coating layer made of a silicon resin is formed on the surface of magnetic particles.

In the image forming method of the present invention, a developer layer composed of a two-component developer containing a toner and a carrier is conveyed to a development area by a developer conveying carrier so as not to contact the latent image carrier. And an image forming method including a step of developing an electrostatic latent image on the latent image carrier under an oscillating electric field obtained by applying an AC bias voltage to the developer carrying carrier,
The developer is characterized by comprising colored particles and organic fine particles, and the organic fine particles are composed of a fluorine-containing polymerizable compound (co) polymer having a crosslinked structure.

[0023]

[Action]

(1) Since the fluorine-containing polymerizable compound (co) polymer having a crosslinked structure, which constitutes the organic fine particles, is a hydrophobic resin, the charge amount of the developer containing the organic fine particles depends on the humidity. Not easily affected. Therefore, it has a sufficient amount of charge without depending on the environment,
Excellent transfer characteristics are exhibited even in a high temperature and high humidity environment.

Since the fluorine-containing polymerizable compound (co) polymer having a cross-linking structure, which constitutes the organic fine particles, is a resin having a low surface energy, the developer containing the organic fine particles is a toner for the photoreceptor. Has a small physical adhesive force and is excellent in transfer characteristics from this viewpoint as well.

The fluorine-containing polymerizable compound (co) polymer having a cross-linking structure, which constitutes the organic fine particles, has an F group in the main chain and is a (co) polymer having a cross-linking structure. Therefore, it has excellent strength and is hard to be deformed. As a result, the organic fine particles do not adhere to the developing sleeve or the carrier and contaminate them, and thus it is possible to stably form a copy image many times.

(2) The organic fine particles are also interposed between the colored particles and the photosensitive member and also have a role as a spacer for regulating the distance between the colored particles and the photosensitive member. Therefore,
By defining the particle size (primary average particle size, BET specific surface area) of the organic fine particles within a specific range, the distance between the colored particles and the photoconductor becomes suitable via the organic fine particles, and the colored particles and the photoconductor The electrostatic adhesive force with the body is alleviated, and the transfer characteristics can be improved also from this viewpoint.

(3) When a resin-coated carrier having a resin coating layer made of a silicone resin is used together, a hydrophobic resin is also introduced into the carrier, and the environmental stability of the charge amount is sufficient. And the environmental stability of the image density is excellent. Hereinafter, the present invention will be described in detail.

The developer of the present invention is a developer containing a toner containing colored particles and organic fine particles.

[Colored Particles] The colored particles constituting the toner are not particularly limited as long as they contain at least a binder resin and a colorant, and conventionally known colored particles can be used. Volume average particle size is 4
Colored particles having a particle size of up to 10 μm are preferable because they are excellent in fine line reproducibility of a copy image formed.

[Organic Fine Particles] The organic fine particles constituting the toner are particles contained as an external additive of the toner.

The developer of the present invention is characterized in that the organic fine particles constituting the developer are composed of a homopolymer or copolymer of a fluorine-containing polymerizable compound having a crosslinked structure and having a fluorine group in the main chain. Have

The fluorine-containing unsaturated polymerizable compound used for forming the fluorine-containing polymerizable compound (co) polymer used in the present invention includes the followings, but is not particularly limited thereto. Absent.

Fluorovinyl, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, trifluorochloroethylene, hexafluoropropylene, dichlorodifluoroethylene, and other fluoroolefins, or derivatives thereof. Two or more kinds of these fluorine-containing unsaturated polymerizable compounds may be used.

These copolymers are composed of a repeating unit having a fluorine group in the main chain and another repeating unit.

Examples of the other repeating units include monomers such as aliphatic olefins, halogenated aliphatic olefins, conjugated diene aliphatic olefins, aromatic vinyl compounds, nitrogen-containing vinyl compounds, and (meth) acrylic acid alkyl esters. The repeating unit to be introduced may be mentioned, and two or more kinds of them may be combined to form a copolymer.

Specific examples of the above-mentioned monomer used for introducing another repeating unit include, for example, JP-A-64 / 1988.
The monomers exemplified in JP-A-33562 can be mentioned, and among these monomers, styrene, methylstyrene, and alkyl (meth) acrylate are particularly preferable from the viewpoint of controlling the charge amount. In the copolymer of the fluorine-containing polymerizable compound, the content of the repeating unit having a fluorine group in the main chain is preferably 55% by weight or more from the viewpoints of good transfer characteristics and environmental stability of image density. .

The above-mentioned (co) polymer of the fluorine-containing polymerizable compound has a crosslinked structure, and a crosslinking agent is used in the production of organic fine particles.

Examples of the cross-linking agent include ethyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and triethylene glycol dimethacrylate. Methylolethane trimethacrylate,
Polyhydric alcohol methacrylates such as pentaerythritol tetramethacrylate; diethylene glycol diacrylate, triethylene glycol diacrylate,
Polyhydric alcohol acrylates such as tetraethylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol tetraacrylate; polyfunctional vinylbenzenes such as divinylbenzene; other compounds They can be used alone or in combination.

The amount of the cross-linking agent used is preferably 0.1 to 30% by weight based on all the monomers.

As described above, the organic fine particles constituting the developer of the present invention have both the hydrophobic property and the low surface energy property which are the properties of the (co) polymer of the fluorine-containing polymerizable compound. Therefore, the developer of the present invention containing the toner containing the organic fine particles has excellent transfer characteristics.

The (co) polymer of the fluorine-containing polymerizable compound constituting the organic fine particles has a fluorine atom as a substituent of the main chain and has a crosslinked structure (co) polymer. Therefore, it is excellent in strength and is not easily deformed. Furthermore, the glass transition point is higher than that of other types of fluorine-containing resins, and fusion to a carrier or the like is less likely to occur.

Therefore, even when the developer of the present invention containing the toner containing the organic fine particles is used to repeatedly form a copy image a number of times, the organic fine particles adhere to and melt on the developing sleeve or the carrier. It does not contaminate them by wearing them, causing white stripes in the formed copy image,
There is no problem of causing contamination inside the machine due to toner scattering.

The organic fine particles constituting the developer of the present invention are
The primary average particle diameter is preferably 50 to 500 nm, more preferably 50 to 300 nm.

The BET specific surface area of the organic fine particles is 10
It is preferably about 120 m ² / g.

By defining the size of the organic fine particles as described above, the distance between the colored particles and the photoconductor becomes appropriate via the organic fine particles as an external additive, and the colored particles and the photoconductor are separated from each other. The electrostatic adhesive force can be relaxed and the transfer characteristics can be further improved.

When the organic fine particles have a primary average particle diameter of less than 50 nm or a BET specific surface area of 120 m ² / g
If it exceeds, the electrostatic adhesion between the colored particles and the photoconductor cannot be relaxed, and the effect of improving the transfer characteristics cannot be sufficiently achieved. On the other hand, when the primary average particle diameter of the organic fine particles exceeds 500 nm or when the value of the BET specific surface area is less than 10 m ² / g, the organic fine particles are not sufficiently fixed to the colored particles and are separated. In some cases, the chargeability of the toner may be hindered.

The shape of the organic fine particles is preferably spherical. By using the spherical organic fine particles, the contact area of the toner with the photoconductor is reduced, and the transfer characteristics can be further improved.

The organic fine particles constituting the present invention can be prepared by a conventionally known polymerization method. In order to obtain spherical organic fine particles, an emulsion polymerization method, a soap-free emulsion polymerization method, a suspension polymerization method or the like is used. It can be preferably used. Alternatively, the polymer obtained by any of these various polymerization methods, solution polymerization methods, bulk polymerization methods and the like may be dissolved in a solvent and then granulated by a spray drying method. Among these, the soap-free emulsion polymerization method is particularly preferable from the viewpoints that the particle size and shape are easily controlled and the charge amount has little humidity dependency.

The organic fine particles are added to the colored particles as an external additive to form a toner. The amount of the organic fine particles added varies depending on the particle diameter of the colored particles, but is preferably about 0.1 to 10% by weight with respect to the colored particles of 4 to 10 μm.

External additives other than organic fine particles may be added to the toner constituting the developer of the present invention. The external additive is not particularly limited, but a fluidity improver such as silica or titanium oxide can be preferably used.

[Carrier] The developer of the present invention may be used as a one-component developer composed of only a toner, or may be used as a two-component developer composed of a toner and a carrier.

The carrier to be used as a two-component developer is not particularly limited, but from the viewpoint of environmental stability of image density (reproducibility stability of density), a resin coating layer made of a silicone resin is used. A resin-coated carrier formed on the surface of magnetic particles is preferable.

The magnetic particles constituting the resin-coated carrier are, for example, iron, Cu-Zn ferrite, Cu-
Ferrite such as Zn-Mg ferrite, magnetite or the like can be used as the core material particles.

The average particle size of the magnetic particles is 20 to 90 μm.
It is preferably in the range of m, more preferably 30-80
It is assumed to be μm.

As for the magnetization of the magnetic particles, the magnetization in an external magnetic field of 1000 gauss is preferably in the range of 10 to 50 emu / g, more preferably 15 to 40 emu / g.

By using the magnetic particles having the average particle diameter and the magnetization in such a range, it is possible to improve the developability in the non-contact developing method.

The silicone resin constituting the resin coating layer is not particularly limited, but for example, a room temperature curing reaction type silicone resin represented by the following chemical formula 1 can be preferably used.

[0058]

[Chemical 1]

[In Chemical Formula 1, OX represents a hydroxyl group, an alkoxy group, a ketoxime group, an acetoxy group, or an aminoxy group, and R ¹ and R ² each represent a lower alkyl group having 1 to 6 carbon atoms. In such a room temperature curing reaction type silicone resin, a particularly preferable substituent is a methyl group. In the coating layer obtained by the room temperature curing reaction type silicone resin having a methyl group as a substituent, the structure becomes dense, the water repellency is good, and the carrier having good moisture resistance can be obtained.

When the room temperature curing reaction type silicone resin is used as the silicone resin used for forming the resin coating layer of the carrier, the carrier can be easily manufactured since it does not need to be heated to a particularly high temperature for curing. it can.

The room temperature curing reaction type silicone resin is a silicone resin which cures at a temperature of about 20 to 25 ° C. or a temperature slightly higher than this in a normal atmosphere, and a temperature exceeding 100 ° C. is required for curing. It does not.

As the silicone resin used for forming the resin coating layer of the carrier, the above silicone resins may be used alone or in combination, or the above silicone resin mixed with another resin may be used. May be. It is preferable that the other resin has high compatibility with the silicon resin. Examples of such other resin include acrylic resin, styrene resin, epoxy resin, urethane resin, polyamide resin, polyester resin, acetal resin, polycarbonate resin, phenol resin, vinyl chloride resin, vinyl acetate resin, cellulose resin, polyolefin resin. Examples thereof include copolymer resins, compounded resins and the like.

As a method for forming a resin coating layer made of a silicone resin on the surface of magnetic particles, for example, a resin coating solution in which a silicon resin is dissolved in an organic solvent is prepared, and the resin coating solution is used as carrier core material particles. The method of coating on the surface of, and then drying by heating to remove the solvent and curing. Here, as a method of applying the resin coating liquid,
There is no particular limitation such as dip coating and spray coating fluidized pellet method.

As another means, a resin-coated carrier can be produced by a so-called dry method in which fine particles of a silicon resin are electrostatically adhered to the surface of a carrier core material and thermally and mechanically fixed.

As described above, by using the resin-coated carrier on which the resin coating layer made of the silicone resin is formed, in combination with the low surface energy property of the fluorinated acrylate (co) polymer constituting the organic fine particles, The physical adhesion between the toner and carrier becomes even smaller,
The problem of carrier adhesion can be reliably prevented. Further, since a hydrophobic resin is also introduced into the carrier, the environmental stability of the charge amount of the toner can be sufficiently achieved, and as is clear from the results of Examples described later, the environmental stability of the image density is excellent. When a copy image is formed in a high temperature and high humidity environment, overdevelopment is prevented and a faithful image density can be reproduced.

(4) Image Forming Apparatus FIG. 1 is a schematic explanatory view showing an example of an image forming apparatus which can be used in the present invention. In this image forming apparatus, by moving the document table 10, the illumination light source 11
The image of the original document, which has been irradiated in step (2), is irradiated onto the photoconductor 14 via the mirror 12 and the lens 13, whereby an electrostatic latent image is formed. This electrostatic latent image is developed by the developing device H to form a toner image.

Next, this toner image is transferred to the exposure lamp 15
After the charge is removed by the transfer electrode to facilitate transfer, the transfer electrode 16
Is transferred to the recording paper P by. The recording paper P on which the toner image is transferred is separated from the photoconductor 14 by the separation pole 17 and fixed by the fixing device 31. On the other hand, the transfer residual toner on the photoconductor 14 is removed by the removing electrode 32 and the cleaning device 33. The cleaning device 33 includes a blade 34 for scraping off the transfer residual toner and a roller 36 for collecting the scraped toner.

(5) Developing Device FIG. 2 is a schematic explanatory view showing the structure of the non-contact developing device mounted on the image forming apparatus.

In the figure, reference numeral 20 denotes a developer carrying carrier, and this developer carrying carrier 20 has a magnet roll 21 having N and S alternating magnetic poles of 8 poles rotating in the direction of the arrow, and the magnet roll 21 opposite to the magnet roll 21. And a developing sleeve 22 that rotates in the direction to convey the developer layer to the developing area K. Reference numeral 23 denotes a developer amount regulating member formed of an elastic pressure contact plate that presses the developing sleeve 22 to regulate the layer thickness of the developer layer, and 24.
Is an AC bias power source for forming an oscillating electric field, 25
Reference numerals 26 and 26 denote a stirring device that rotates in the direction of the arrow, 27 a toner replenishing roller, 28 a toner hopper, and T a replenishment toner.

The magnetic pole strength (magnetic flux density) in the developing region of the magnet roll 21 is 500 to 1500 gauss, and the magnet roll 21 may be rotated in the same direction as the developing sleeve 22 or may be fixed. . The number of magnetic poles is 4 to
It may be appropriately selected within the range of 20 poles, but it is preferably 6 poles or more from the viewpoint of evenly conveying the developer. The developing sleeve 22 is preferably made of a non-magnetic material such as copper, aluminum or magnesium. If necessary, the surface may be roughened by sandblasting or the like, and the surface may have high resistance.

The pressing force of the developer amount regulator 23 is 0.
It is set to 1 to 5 g / cm and is suitable for forming a thin developer layer of 20 to 500 μm which is desired when performing non-contact development of a developer layer composed of a two-component developer.

In the developing area K, the gap between the photoconductor 14 rotating in the direction of the arrow and the developing sleeve 22 is larger than the thickness of the developer layer and is usually 100 to 1000 μm, which enables non-contact development under an oscillating electric field. Is set to.

With the AC bias power source 24, normally 100
A bias of 0.2 to 3.0 KV (PP), preferably 1.0 to 2.0 KV (PP) is applied at a frequency of Hz to 10 kHz, preferably 1 to 5 kHz.

Further, in order to prevent the occurrence of fog, in the case of regular development, a DC bias of the same polarity as that of the electrostatic latent image is applied by superimposing 50 to 500 V, and in the case of reversal development, electrostatic latent image is applied. A DC bias close to the image potential is applied.

The stirring devices 25 and 26 are provided with a plurality of stirring blades inclined to their respective rotation axes, and the stirring blades are designed so as to rotate in the same region in an overlapping manner without colliding with each other. There is. Therefore, the developer is moved and agitated in the direction of the rotation axis and in the direction perpendicular thereto, and the triboelectrification and uniform mixing of the developer are sufficiently achieved.

[0076]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these modes. In the following, "part" means "part by weight".

The primary average particle size of the organic fine particles can be determined by measuring the emulsion after completion of the emulsion polymerization with a particle size distribution measuring device "LPA-3".
000 ”(manufactured by Otsuka Electronics Co., Ltd.), and the BET specific surface area is measured by a BET specific surface area measuring device“ Flow Sorb ”.
II 2300 "(manufactured by Shimadzu Corporation).

[Part 1] <Example 1> (1) Preparation of organic fine particles A soap-free emulsion was prepared by using a monomer mixture containing 95% by weight of a monomer component made of vinylidene fluoride and 5% by weight of divinylbenzene (crosslinking agent). Polymerization was carried out.
The obtained emulsion is filtered by a filtration device to obtain a polymer, the obtained polymer is washed, and then dried by a spray dry dryer to obtain a primary average particle diameter of 70 nm and BET.
Organic fine particles A having a specific surface area of 121 m ² / g were produced.

(2) Preparation of toner Polyester resin "UXK-120P" (manufactured by Kao Corporation) 1
After preliminarily mixing 00 parts and 10 parts of carbon black "Mogal L" (manufactured by Cabot), kneading, crushing, crushing and classification were performed to obtain colored particles having an average particle size of 8.5 µm.

2. The organic fine particles A were added to the colored particles thus obtained.
0% by weight was added, and a hydrophobized silica "Aerosil R805" (manufactured by Nippon Aerosil Co., Ltd.) was added.
0% by weight was added and mixed with a Henschel mixer to prepare a toner.

(3) Preparation of Carrier A room temperature curing reaction type methyl silicone resin was dissolved in toluene to prepare a coating solution, and the obtained coating solution was used as core material particles (Cu-Zn ferrite particles having an average particle size of 80 μm). A carrier was prepared by applying the composition on the surface of, and then drying by heating to remove the solvent and cure.

(4) Manufacture of Developer A toner and a carrier were mixed in a ratio such that the toner concentration was 4% by weight to manufacture the developer 1 of the invention.

Example 2 A primary average was obtained in the same manner as in Example 1 except that a monomer mixture containing 93% by weight of a monomer component consisting of tetrafluoroethylene and 7% by weight of divinylbenzene (crosslinking agent) was used. Particle size is 110n
m, an organic fine particle B having a BET specific surface area of 62 m ² / g
Was produced.

A developer 2 of the present invention was manufactured in the same manner as in Example 1 except that the organic fine particles B were used instead of the organic fine particles A.

<Example 3> (1) Preparation of organic fine particles and toner Example 1 except that a monomer mixture consisting of 90% by weight of hexafluoropropylene and 10% by weight of ethylene glycol diacrylate (crosslinking agent) was used. Similarly, the average primary particle diameter is 130 nm and the BET specific surface area is 53
Organic fine particles C having m ² / g were produced. Using this, a toner was prepared in the same manner as in Example 1.

(2) Preparation of Carrier 96 parts of room temperature curing reaction type methyl silicone resin and 4 parts of amino-modified silicone resin were dissolved in toluene to prepare a coating solution, and the obtained coating solution was mixed with core material particles ( Average particle size 80μm
Of Cu--Zn ferrite particles), and then dried by heating to remove the solvent and cure to prepare a carrier.

(3) Manufacture of Developer A developer 3 of the present invention was manufactured by mixing the toner and the carrier in a ratio such that the toner concentration was 4% by weight.

Example 4 (1) Monomer component 95 consisting of 60 parts of vinylidene fluoride and 40 parts of methyl methacrylate (copolymerizable monomer)
An organic compound having a primary average particle size of 330 nm and a BET specific surface area of 34 m ² / g in the same manner as in Example 1 except that a monomer mixture consisting of 5% by weight and 5% by weight of divinylbenzene (crosslinking agent) was used. Fine particles D were prepared. Using this, a toner was prepared in the same manner as in Example 1.

(2) Preparation of Carrier A styrene-methylmethacrylate resin was dissolved in toluene to prepare a coating solution, and the obtained coating solution was applied to the surface of core material particles (Cu-Zn ferrite particles having an average particle size of 80 μm). Then, the carrier was prepared by coating the same on a substrate and then drying by heating to remove the solvent and cure.

(3) Production of Developer A developer 4 of the present invention was produced by mixing the toner and the carrier in a ratio such that the toner concentration was 4% by weight.

Example 5 (1) Preparation of Organic Fine Particles and Toner A toner containing organic fine particles E prepared in the same manner as in Example 4 except that methylmethacrylate was changed to hexafluoropropylene was prepared.

However, divinylbenzene is 10% by weight, the average primary particle size is 470 nm, and the BET specific surface area is 25 m ² / g.
Is.

(2) Production of Carrier and Production of Developer A developer 5 of the present invention was produced by mixing the toner and the carrier in a ratio such that the toner concentration was 4% by weight.

<Comparative Example 1> A primary average particle size of 210 n was obtained in the same manner as in Example 1 except that the crosslinking agent was not used.
m, an organic fine particle a having a BET specific surface area of 45 m ² / g
Was produced.

Comparative developer 1 was produced in the same manner as in Example 1 except that the organic fine particles a were used instead of the organic fine particles A.

Comparative Example 2 The primary average particle diameter was 180 nm and the BET specific surface area was 46 m ² / g in the same manner as in Example 4 except that styrene was used instead of vinylidene fluoride.
To produce organic fine particles b.

Comparative developer 2 was produced in the same manner as in Example 1 except that organic fine particles b were used instead of organic fine particles A.

<Comparative Example 3> A sample was prepared in the same manner as in Example 1, but the particle size of organic fine particles 690 was controlled by controlling the preparation conditions.
nm, and BET specific surface area was 8.3 m ² / g Organic fine particles c were prepared.

Comparative developer 3 was produced in the same manner as in Example 1 except that the organic fine particles c were used in place of the organic fine particles A.

<Comparative Example 4> In the same manner as in Comparative Example 3, organic fine particles d having a particle size of 19 nm and a BET specific surface area of 175 m ² / g were produced by controlling the producing conditions. Comparative Developer 4 was manufactured in the same manner as in.

<Actual Copy Test> For each of the developers 1 to 5 and the comparative developers 1 to 4 of the present invention obtained as described above, a recycle type electrophotographic copying machine for recycling the cleaning toner to the developing device “ U-BIX5082 "
[Konica Corporation] was used for 50,000 times of live-copy test, and transfer rate under high temperature and high humidity environment (30 ° C, relative humidity 90%), in-machine contamination due to toner scattering, occurrence of white stripes, high temperature The image density was evaluated under a high humidity environment (30 ° C., relative humidity 90%) and a low temperature low humidity environment (10 ° C., relative humidity 20%).

The transfer material is JIS K 69.
The surface resistance value according to 11 is 8.5 × 10 ⁸ Ω (20 ° C., 6
5%) transfer paper was used.

The evaluation method of each item is as follows.

(1) Transfer Rate After the image formation was performed 50,000 times, the transfer rate was obtained as follows. That is, a solid toner image having a size of 20 mm × 50 mm is formed on the photoconductor, and this toner image is sampled with an adhesive tape before the transfer step to measure the toner weight w ₁ . The same solid toner image as above is formed on the photoconductor, and this toner image is subjected to a transfer step and transferred to a transfer paper,
The weight w ₂ of the toner remaining on the photoconductor after the transfer is measured. Toner weights w ₁ and w thus measured
_{From 2, the} transfer rate was calculated by the following formula. Transfer rate = (w ₁ −w ₂ ) / w ₁ × 100 (%) (2) Contamination inside the machine Visually observe the inside of the copying machine every 1000 times of image formation,
It was evaluated by the number of times of copying when a certain degree of practical contamination was observed.

(3) White streak A copy image of an original consisting of a gray chart having an image density of 0.50 is formed, and the obtained copy image is visually observed for the presence or absence of white streak. Evaluation was made by the number of times of copying when it was recognized.

(4) Image Density A copy image of an original consisting of a chart having an image density of 0.50 was formed, and the image density of the obtained copy image was measured. The closer the image density is to 0.50, the more faithfully the image density is reproduced.

The above evaluation results are shown in Tables 1 and 2 below.

(5) Adhesion of Carrier After forming an image 55 times, an image of a solid black chart is formed, and the carrier adhering to the photoreceptor is sampled with an adhesive tape before the transfer step. The number was measured and the number per unit area was measured. (Pieces / cm ² )

[0109]

[Table 1]

[0110]

[Table 2]

As is clear from the results shown in Tables 1 and 2, the developers 1 to 5 of the present invention have a high transfer rate and are free of transfer unevenness and excellent in transfer characteristics. Moreover, according to the developer of the present invention, it is possible to stably perform a large number of image formations without generating in-machine contamination or white streaks even when the image formation is performed 50,000 times.

Further, the developer of the present invention [in particular, the developer of the present invention 1 containing a resin-coated carrier made of a silicone resin]
3 (Examples 1 to 3)], it is possible to reproduce a faithful image density under any environment of high temperature and high humidity and low temperature and low humidity.

On the other hand, since the comparative developer 1 contains organic fine particles having no crosslinked structure, the comparative developer 2 has organic fine particles made of a crosslinked resin containing no fluorine. Therefore, in the actual shooting test, in-machine contamination and white stripes are generated, and it is not possible to stably perform image formation many times.

[Part 2] The same test was performed using the same organic fine particles as in Example 1.

However, only the following conditions were changed.

Hydrophobized silica "Aerosil R805" added to the toner was changed to "Aerosil R972" (manufactured by Nippon Aerosil Co., Ltd.).

Carrier core material particles “C having an average particle size of 80 μm
“U-Zn ferrite particles” is defined as “average particle size 50 μm, 10
Changed to "Cu-Zn-ferrite particles having a magnetization of 20 emu / g in an external magnetic field of 00 Gauss".

The ratio of toner to carrier was changed from 4% by weight to 7% by weight.

Copier "U-BIX50" using a live-action test
82 "is a non-contact development type image forming apparatus" Konica 902
8 ”[made by Konica Corporation].

The test results, as shown in Table 3, show that the present invention is excellent as in Example 1.

[0121]

[Table 3]

[0122]

According to the developer of claim 1, the organic fine particles constituting the toner have a crosslinked structure and are formed from a (co) polymer of a fluorine-containing polymerizable compound having a fluorine group in the main chain. Therefore, good transfer characteristics are exhibited even when the image is formed in a high temperature and high humidity environment, and a plurality of copied images can be stably formed.

According to the developer of the second aspect, since the primary average particle diameter and the BET specific surface area of the organic fine particles constituting the toner are regulated within a specific range, the electrostatic charge between the colored particles and the photoconductor is reduced. The adhesive force can be relaxed, and the transfer characteristics can be further improved.

According to the developer of claim 3, since the resin-coated carrier made of a silicone resin is contained,
In addition to the above effects, the image density is excellent in environmental stability, and faithful image density can be reproduced even in a high temperature and high humidity environment.

According to the fourth aspect of the present invention, excellent transfer characteristics are exhibited even in a high temperature and high humidity environment, carrier adhesion is suppressed, and moreover, copy images are stably formed many times. You can

According to the invention of claim 5, the transfer characteristics can be further improved.

According to the invention of claim 6, the effect of preventing carrier adhesion is further improved, the environmental stability of the image density is excellent, and the faithful image density can be reproduced even in a high temperature and high humidity environment.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram illustrating an example of an image forming apparatus that can be used in the present invention.

FIG. 2 is a schematic explanatory diagram showing a configuration of a non-contact developing device mounted in the image forming apparatus.

[Explanation of symbols]

 10 Document Plate 11 Illumination Light Source 12 Mirror 13 Lens 14 Photosensitive Body 15 Exposure Lamp 16 Transfer Electrode 17 Separation Electrode 20 Developer Transport Carrier 21 Magnet Roll 22 Developing Sleeve 23 Developer Amount Regulator 24 AC Bias Power Supply 25 Stirrer 26 Stirrer 27 Toner supply roller 28 Toner hopper 31 Fixer 32 Remover electrode 33 Cleaning device 34 Blade 36 Roller

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroyuki Takagaki 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Stock Company

Claims (6)

[Claims] 1. A developer containing a toner containing colored particles and organic fine particles, wherein the organic fine particles have a crosslinked structure and a single weight of a fluorine-containing polymerizable compound having a fluorine group in the main chain. A developer which is a polymer or a copolymer. 2. The organic fine particles have a primary average particle diameter of 50 to 500 nm, and have a BET specific surface area of 10 to 120.
The developer according to claim 1, wherein the developer is m ² / g. 3. The developer according to claim 1, wherein the resin coating layer made of a silicone resin contains a resin coated carrier formed on the surface of the magnetic particles. 4. A developer layer comprising a two-component developer containing a toner and a carrier is conveyed to a developing area in a state where it is not in contact with a latent image carrier by a developer conveying carrier, and the developer is conveyed. In an image forming method including a step of developing an electrostatic latent image on the latent image carrier under an oscillating electric field obtained by applying an AC bias voltage to a carrier, the toner constituting the developer is colored particles, An image forming method comprising: an organic fine particle, wherein the organic fine particle has a crosslinked structure, and is composed of a homopolymer or copolymer of a fluorine-containing polymerizable compound having a fluorine group in the main chain. . 5. The image forming method according to claim 4, wherein the organic fine particles have a primary average particle diameter of 50 to 500 nm,
Further, the BET specific surface area is 10 to 120 m ² / g, and the image forming method. 6. The image forming method according to claim 4 or 5, wherein the carrier constituting the developer is a resin-coated carrier having a resin coating layer made of a silicone resin formed on the surface of magnetic particles. An image forming method characterized by the above.