JPH07295283A - Two-component developer and image forming method - Google Patents

Abstract

PURPOSE:To provide a two-component developer with which images faithful to latent images and having high image densities, high resolution and high fineness reproducibility substantially free from fog are obtainable. CONSTITUTION:The toners of the two-component developer having the magnetic carriers and toners to be used for a copying device consist of a binder resin and coloring agents. The weight average grain size of the toners is 4 to 8.5mum. The toner particles of <=5mum are 17 to 80 number % and the toner particles of 6.35 to 10.08mum are 5 to 70 number %. The toner particles of >=12.7mum are incorporated at <=2.0vol.% in the toners. The toner particles of <=5m satisfy the equation. N/V=0.05N+ k (where, N denotes the number % of the toner particles of <=57mum, V denotes vol.%, k denotes a positive number of 4.6 to 6.7).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-component developer used for developing an electrostatic latent image in electrophotographic copying machines, printers, etc., and particularly to an OPC belt photosensitive member as a latent image bearing member and a cleaning member. The present invention relates to a high-speed image forming method using a brush cleaning method as a means.

[0002]

2. Description of the Related Art Conventionally, a large number of electrophotographic methods are known, but generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is formed. The image is developed with a developer to make it a visible image, and if necessary, the developer image is transferred to a transfer material such as paper, and then the developer image is fixed on the transfer material by heat, pressure, etc. Is what you get. In recent years, the number of devices using electrophotography has increased to printers, facsimiles, etc. in addition to conventional copying machines. Among them, in the fields of copying machines and printers, higher speed and stability are always desired. In these high-speed copying machines or high-speed printers, the two-component developing system is the mainstream.

This is because the two-component toner does not contain a large amount of magnetic material as compared with the one-component magnetic toner, and as a result,
This is because the fixability becomes extremely advantageous especially in a high-speed machine. Further, in recent years, from the viewpoint of environmental protection and energy saving against environmental problems, there is a strong demand for reduction of power consumption in large-sized and high-speed copying machines and printers, and as copy paper, so-called recycled paper has become the mainstream. . However, the use of these recycled papers is generally disadvantageous to the fixability, and the developing method using a two-component toner having good fixability is also a preferable developing method especially for high-speed machines. (Generally, most of the power consumed by copiers and printers that use the heat fixing method is used as the heat source of the fixing device).

In recent years, as an electrophotographic photosensitive member, an organic photosensitive member called OPC has come to be used in place of an inorganic photosensitive member such as selenium. OP
Generally, the C photoconductor has an undercoat layer UCL and a charge generation layer CG on a conductive substrate CB as shown in FIG.
L, charge transport layer CTL having a three-layer structure, or FIG.
As shown in (b), the charge generation layer C is formed on the conductive substrate CB.
There is a two-layer structure having a GL and a charge transport layer CTL. The undercoat layer UCL and the charge generation layer CGL are usually 1 μm or less in thickness, and the charge transport layer CTL is 10 to 30 μm.
It is about a film thickness.

Of these layers, the charge transport layer CTL, which is in direct contact with the cleaning member and the developing member, is an organic material, and therefore is generally easily scratched and worn. Causes of this wear include contact with the developing system and copy paper, but the largest is due to the cleaning member (blade, fur brush). Particularly in high-speed machines, the abrasion resistance of the photoconductor is required so that it can endure a very large amount of copying and printing. For this reason, in a high-speed machine, a belt-shaped OPC photosensitive member having flexibility that allows a large effective use area of the photosensitive member surface and relatively soft cleaning of the photosensitive member are performed. The combination of brush cleaning that can be done is the mainstream. However,
Even with such a combination, it is not sufficient for a large number of copies of over one million sheets, and higher durability is desired.

In recent years, higher definition of copied images has been realized.
High resolution is strongly desired. For example, in LBP printers and the like, conventional 240, 300 dpi to 400, 60
It is moving toward higher resolutions such as 0, and even 800 dpi. However, in response to these requests,
The conventional two-component developer has a problem that coarse toner particles gradually accumulate in the developer due to selective development of toner particles in a large number of copies and prints for a long period of time, resulting in a decrease in image resolution. . On the other hand, as a developing method for obtaining such a high-definition / high-resolution image, a developer having a small particle size has been proposed as disclosed in JP-A-1-112253 and JP-A-2-284158.

However, when the weight average particle diameter of the toner is small (generally 9 μm or less), the toner particles are apt to be overcharged, which is called charge-up, especially in a low humidity environment. It adheres strongly to the surface and the surface of the photoconductor, resulting in unfavorable problems such as reduction in image density and fogging, poor cleaning of the photoconductor, and filming on the photoconductor. In particular, the problems of poor cleaning and filming tend to be accelerated by the use of the above-mentioned recycled copy paper (since recycled paper produces a large amount of paper powder and filler powder). These problems are problems that must be improved by all means in order to achieve the high-definition / high-resolution image and high durability described above.

[0008]

In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a high image density, high resolution and high definition reproducibility that is faithful to a latent image and is substantially free of fog. It is to provide a two-component developer capable of obtaining the above image.

A further object of the present invention is to prevent coarse toner particles from accumulating in the developer and abrasion of the photoconductor even during high-speed mass copying / long-term use, to prevent defective cleaning and filming, and to stably provide a high image density. -To provide an image forming method capable of obtaining a high-resolution / high-definition copied image.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a latent image is formed on a moving or rotating latent image carrier, the latent image is developed with a developer, and the developed toner image is carried on the latent image carrier. A two-component developer having a magnetic carrier and a toner, which is used in a copying apparatus including a transfer unit that transfers a toner from a body to a support surface and a cleaning unit that removes residual toner and foreign matter from a latent image carrier, Is composed of at least a binder resin and a colorant, and the toner has a weight average particle diameter of 4 to 8.
5 μm, toner particles of 5 μm or less are contained in 17 to 80% by number, toner particles of 6.35 to 10.08 μm are contained in 5 to 70% by number, toner particles of 12.7 μm or more are 2.0% by volume. The toner particles contained below and having a particle size of 5 μm or less are represented by the following formula N / V = −0.05N + k (wherein N represents the number% of the toner particles having a particle size of 5 μm or less,
V represents the volume% of the toner particles of 5 μm or less, and k is 4.
A positive number of 6 to 6.7 is shown. ) Is satisfied, it relates to a two-component developer.

According to the present invention, a latent image is formed on a moving or rotating latent image carrier, and the latent image is developed with a two-component developer,
In a method of forming an image, which includes a transfer unit that transfers a developed toner image from a latent image carrier to a support surface and a cleaning unit that removes residual toner and foreign matter from the latent image carrier, a magnetic toner is used as a two-component developer. The present invention relates to an image forming method using a developer having a carrier and a toner having the above particle size distribution.

Further, in the present invention, the latent image carrier is OP
The present invention relates to a two-component developer and an image forming method which are C-belt photoreceptors.

Further, the present invention relates to a two-component developer and an image forming method which are a brush cleaning system using a roll-shaped toner disturber brush in which the cleaning means rotates.

A two-component developer having a toner and a magnetic carrier having the above-mentioned particle size distribution and containing a predetermined amount of inorganic fine powder which has been subjected to a hydrophobizing treatment, forms an electrostatic latent image formed on a photoreceptor with fine lines. The performance of faithful reproduction up to the end has been improved, and high resolution and high definition image quality are maintained even when a large number of copies and prints are continued, and cleaning failure and filming even when using recycled paper. It is possible to form an extremely stable image without causing problems such as the above.

The reason why such effects are obtained in the toner according to the present invention is not always clear, but it is presumed as follows.

That is, in the toner of the present invention, 5 μm
One of the characteristics is that the toner particles having the following particle diameters are 17 to 80% by number. Conventionally, toner particles having a particle size of 5 μm or less are difficult to control the charge amount, impair the fluidity of the toner and cause carrier contamination, components causing cleaning problems and filming problems, and toner scattering. It has been considered necessary to positively remove or reduce the components that stain the inside of the image forming apparatus. However, according to the study by the present inventors, it has been found that toner particles of 5 μm or less are essential components for forming a high-definition / high-resolution image. For example, a toner having a particle size distribution ranging from 0.5 to 30 μm is used to change the surface potential on the photoconductor, and a large development contrast, in which a large number of toner particles are easily developed, is changed to a halftone potential, and a very small amount of toner particles are used. The electrostatic latent image on which the potential on the surface of the photoconductor was changed to a small development potential contrast where only the image was developed, the toner particles on the developed photoconductor were collected, and the particle size distribution was measured. Many toner particles, especially 5μ
It was found that there are many toner particles of m or less. That is, if the toner particles of 5 μm or less, which are most suitable for development, are smoothly supplied during the development of the latent image on the photoconductor, they are faithful to the latent image.
An image with excellent reproducibility can be obtained without protruding from the latent image.

Further, in the toner according to the present invention,
One feature is that the toner particles in the range of 35 to 10.08 μm are 5 to 70% by number. This is related to the necessity of the presence of toner particles of 5 μm or less as described above, and the toner particles of 5 μm or less have the ability to exactly cover the latent image and faithfully reproduce it. The electrolytic strength of the peripheral edge portion is higher than that of the central portion, so that the inside of the latent image has thinner toner particles than the edge portion, and the image density may appear lighter. Especially 5μ
The toner particles of m or less have a strong tendency. However,
The present inventors have found that by containing 5 to 70% by number of toner particles in the range of 6.35 to 10.08 [mu] m, this problem can be solved, and the problem can be further clarified. That is, toner particles having a particle diameter of 6.35 to 10.08 μm are 5
It is considered that this is because the toner particles having a particle size of less than or equal to μm have an appropriately controlled charge amount, but the toner particles are supplied to the inside of the latent image where the electric field strength is smaller than the edge portion, and the toner particles inside A uniform developed image is formed by compensating for the small amount of glue, and as a result, a sharp image excellent in resolution and gradation is formed at high density.

Further, for toner particles of 5 μm or less, N / V = −0.05 N + k (where 4.6 ≦ k ≦ 6.7; between the number% (N) and the volume% (V)). One of the characteristics is that the toner of the present invention satisfies the relationship of 17 ≦ N ≦ 80). Figure 3 shows this range, but with other features,
A developer containing toner particles having a particle size distribution satisfying this range can achieve excellent developability even for a digital latent image formed from minute spots. We have 5μ
In examining the particle size distribution of toner particles of m or less, it was found that there is a state of existence of fine powder that is most suitable for achieving the purpose represented by the above formula. That is, the fact that N / V is large with respect to a certain value of N indicates that toner particles of 5 μm or less are widely included, and the fact that N / V is small means that toner particles of 5 μm or less are included. A high abundance and less toner particles below that, N / V values in the range 0.6 to 5.85 and N in the range 17 to 80, In addition, when the above relational expression is satisfied, and when the hydrophobically treated inorganic fine powder is contained in an amount of 0.05 to 5% by weight with respect to the toner, good fine reproducibility and long-term, large-volume copying and printing can be obtained. In addition to high resolution, good cleaning properties of the OPC photoreceptor and less wear (high durability) are achieved. Further, for toner particles of 12.7 μm or more, 2.0
It is preferable that the content is not more than volume% and is as small as possible.

The developer of the present invention solves the problems of the prior art and makes it possible to withstand severe demands for high image quality and high durability of the photoreceptor in recent high speed image forming apparatuses. The effect of the present invention is that the linear velocity of the photoconductor is 500 m.
A particularly remarkable effect was recognized in the image forming apparatus of m / sec or more.

The constitution of the present invention will be described in more detail.

Toner particles of 5 μm or less have a total particle number of 17
˜80% by number, preferably 25-60
The number% is good, and more preferably 30 to 60%. When the number of toner particles having a particle size of 5 μm or less is less than 17% by number, there are few toner particles effective for high image quality. Particularly, by continuing copying, the toner particle components necessary for achieving high image quality are reduced and the toner particle size distribution is reduced. It deteriorates and the image quality gradually deteriorates. On the other hand, when it exceeds 80% by number, toner particles are likely to aggregate with each other and charge up easily, resulting in poor cleaning, lowering of image density, and a large difference in density between the edge portion and the inside of the latent image, so-called hollow image. It is easy to become an image of.

The toner particles in the range of 6.35 to 10.08 μm are preferably 5 to 70% by number, and more preferably 8 to 50% by number. If it is more than 70% by number, the image quality is deteriorated and more than necessary development, that is, toner excessively occurs, the fine line reproducibility is deteriorated, and the toner consumption is increased.

On the other hand, if it is less than 5% by number, it is difficult to obtain a high image density. Further, between the number% (N%) and the volume% (V%) of the toner particle group having a toner particle size of 5 μm or less, N / V =
There is a relationship of −0.05N + k (k is a positive number in the range of 4.6 ≦ k ≦ 6.7), preferably 4.6 ≦ k ≦ 6.2,
More preferably, 4.6 ≦ k ≦ 5.7. Also, 1
7 ≦ N ≦ 80, preferably 25 ≦ N ≦ 60, and more preferably 30 ≦ N ≦ 60. 5.0 for k <4.6
Since the number of toner particles smaller than μm is small, the image density, resolution and sharpness are inferior. The moderate presence of fine toner particles, which was conventionally considered unnecessary, fulfills the closest packing of toner in development, and contributes to the formation of a uniform image. In particular, the sharpness is visually emphasized by uniformly filling the thin line and the contour portion of the image. Also, k
When it is> 6.7, the presence of the fine powder more than necessary tends to cause problems such as a decrease in image density and filming when a large number of sheets are copied or printed.

Further, toner particles having a size of 12.7 μm or more are 2.
It is preferably 0% by volume or less, more preferably 1.0% by volume or less, and further preferably 0.5% by volume or less. If it exceeds 2.0% by volume, the fine line reproducibility tends to be poor.

The weight average particle diameter of the toner is 4 to 8.5 μm.
It is m, and this value cannot be considered separately from the above-mentioned constituent elements. Weight average particle size 4 μm
If it is less than the above range, problems such as stains inside the machine due to toner scattering during long-term use, image density reduction in a low humidity environment, and poor cleaning of the photoconductor tend to occur. When the weight average particle size exceeds 8.5 μm, the resolution of minute spots of 100 μm or less is not sufficient, and scattering to non-image areas is large, resulting in poor image quality. The particularly preferable range of the weight average particle diameter of the present invention is 5.0 to 8.0 μm.

The toner particle size distribution can be measured by various methods, but in the present invention, it was measured using a Coulter counter. That is, a Coulter Counter TA-II type (manufactured by Coulter, Inc.) is used as a measuring device, and an interface (manufactured by Nikkaki) that outputs a number distribution and a volume distribution.
And PC9801 personal computer (NEC
1) is connected, and the electrolyte is 1
% NaCl aqueous solution is prepared. As a measuring method, a surfactant, preferably an alkylbenzene sulfonate, as a dispersant was added to 100 to 150 ml of the electrolytic aqueous solution in an amount of 0.1%.
Add 1 to 5 ml, and further add 2 to 20 mg of the measurement sample.
The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and a particle size distribution of particles of 2 to 40 μm based on the number is measured by the Coulter Counter TA-II type using an aperture of 100 μm as an aperture. The weight-based weight average particle diameter (D) obtained by measuring and calculating the volume distribution and number distribution of particles of 2 to 40 μm
4: The median value of each channel is used as the representative value of the channel).

The two-component developer of the present invention is particularly preferable because it is possible to use the inorganic fine powder subjected to the hydrophobic treatment in the toner. A toner having a particle size distribution as a feature of the present invention has a larger specific surface area than conventional toners. In this case, when mixed with a magnetic carrier and used as a two-component developer, the number of contact between the toner particles and the magnetic carrier is increased as compared with the conventional toner, and the carrier surface is contaminated and the toner particles are worn and crushed. Is likely to occur. By combining the toner of the present invention and the hydrophobized inorganic fine powder, the above phenomenon is remarkably reduced by the presence of the hydrophobized inorganic fine powder between the toner particles and the carrier surface. Similarly, in the cleaning portion of the photoconductor, the presence of the inorganic fine powder subjected to the hydrophobization treatment reduces the abrasion between the toner and the cleaning brush and the photoconductor surface, and the occurrence of scratches on the photoconductor surface. As a result, the life of the developer and the photoconductor can be extended. Further, the toner particles of 5 μm or less, which play an important role in the present invention, further exhibit the effect due to the presence of the inorganic fine powder which has been subjected to the hydrophobic treatment, and can provide a high quality image stably for a long period of time.

As the hydrophobically treated inorganic fine powder of the present invention,
For fine silicate powder, titanium oxide, aluminum oxide
It is preferable to use a hydrophobized metal oxide such as um.
Can be used. For example, silicic acid fine powder may be silicon halogen.
The so-called dry method or
Is a fumed silica called fumed silica, and water glass
Both so-called wet silica produced from
The silano on the surface and inside the fine silica powder
Has a few radical groups, and Na₂O, SO ₃ ^2-Of manufacturing residues such as
Less dry silica is preferred. Used in the present invention
It is particularly preferable that the hydrophobic inorganic fine powder has a positive charging property.
It can be used easily. Particularly, the silica fine powder is used as a nitrogen source in the side chain.
Siri having an organo group having at least one child
Treated with corn oil or nitrogen-containing silane
Treated with coupling agent or both
The above products can be particularly preferably used. Normal belt in the present invention
Electro-hydrophobic inorganic fine powder is measured by blow-off method
Having positive triboelectric charge to iron powder carrier
Say

In the case of dry silica, it is possible to obtain a composite fine powder of silica and another metal oxide by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound in the manufacturing process. And includes them. Inorganic fine powder used in the present invention is measured by nitrogen adsorption according to the specific surface area of 30 m ² / g or more by the BET method, in particular in the range of 50 to 400 m ² / g give good results.

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

[0031]

[Chemical 1]

(Where R is₁Is hydrogen, alkyl group, aryl
R group or alkoxy group, R₂Represents an alkylene group
And R₃And R_FourIs hydrogen, an alkyl group or an aryl group
And R _FiveRepresents a nitrogen-containing heterocycle. )

In the above formula, the alkyl group, the aryl group, the alkylene group and the phenylene group may have an organo group having a nitrogen atom, and may have a substituent such as halogen as long as the chargeability is not impaired. You can do it. The silicone oil is used in an amount of 1 to 50% by weight, preferably 5 to 30% by weight, based on the inorganic fine powder.

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

Rm-Si-Yn

(R represents an alkoxy group or halogen,
Y represents an amino group or an organo group having at least one nitrogen atom, m and n are integers of 1 to 3 and m
+ N = 4. )

Examples of the organo group having at least one nitrogen atom include an amino group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. The nitrogen-containing heterocyclic group includes an unsaturated heterocyclic group and a saturated heterocyclic group, and known ones can be used. Examples of the unsaturated heterocyclic group include the followings.

[0038]

[Chemical 2]

Further, examples of the saturated heterocyclic group include the following.

[0040]

[Chemical 3]

The heterocyclic group used in the present invention is preferably a 5-membered ring or a 6-membered ring in view of stability. Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, Monobutylaminopropyltrimethoxysilane, dioctylaminopropyldimethoxysilane,
There are dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ-propylbenzylamine and the like.

Further, as the nitrogen-containing heterocycle, those having the above-mentioned structure can be used, and examples of such a compound include trimethoxysilyl-γ-propylpiperidine, trimethoxysilyl-γ-propylmorpholine and trimethoxysilyl. -Γ-propylimidazole and the like.

The silane coupling agent is 1 to 50% by weight, preferably 5 to 30% by weight, based on the inorganic fine powder.
Good to use.

The inorganic fine powder used in the present invention may be treated with a treatment agent such as another silane coupling agent, silicone oil, or an organic silicon compound, if necessary. , For example, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α -Chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate,
Examples thereof include vinyldimethylacetoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, and 1,3-diphenyltetramethyldisiloxane. The silicone oil has a viscosity at 25 ° C. of 50 to 100.
Centistokes are used, such as dimethyl silicone oil, methylphenyl silicone oil, α
-Methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil and the like can be mentioned. As a method for treating silicone oil, for example, silica fine powder treated with a silane coupling agent and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or silica fine powder as a base may be treated with silicone. A method of spraying oil may be used.
Alternatively, a method may be used in which silicone oil is dissolved or dispersed in a suitable solvent, and then silica fine powder is added and mixed to remove the solvent.

In the present invention, titanium oxide fine powder having a BET specific surface area of 50 to 400 m ² / g may be used instead of the silicic acid fine powder. Further, a mixture of fine powder of silicic acid and fine powder of titanium oxide may be used.

The degree of hydrophobization of the hydrophobized inorganic fine powder in the present invention is measured by the following method. Of course, other measuring methods can be applied while referring to the measuring method of the present invention. Ion-exchanged water 1 in a sealed stopper 200 ml separating funnel
00 ml and 0.1 g of the sample are added, and the mixture is shaken with a shaker (Turbra shaker mixer T2C type) at 90 rpm for 10 minutes. After shaking, the mixture was allowed to stand for 10 minutes to separate the inorganic fine powder layer and the aqueous layer, and then the lower aqueous layer was added to 20 to 30 ml.
The sample is put in a cell, the transmittance is measured at a wavelength of 500 nm with reference to blank ion-exchanged water containing no inorganic fine powder, and the value of the transmittance is used as the hydrophobicity of the inorganic fine powder. . The hydrophobicity of the hydrophobic inorganic fine powder in the present invention is 80% or more, more preferably 85% or more. When the degree of hydrophobicity is less than 80%, the image quality is deteriorated due to the water adsorption of the inorganic fine powder under high humidity.

The hydrophobically treated inorganic fine powder used in the present invention is preferably used in an amount of 0.05 to 5% by weight, more preferably 0.1 to 3% by weight, and most preferably 0.1% by weight based on the toner. 2 to 2% by weight is good. Below 0.05% by weight,
The effect of improving toner aggregation is poor, and even if the amount exceeds 5% by weight, toner scatters between fine lines, contamination in the machine,
Problems such as scratches and abrasion of the photoconductor tend to occur.

In the developer of the present invention, other additives may be added within a range that does not have a substantial adverse effect, for example, lubricant powder such as Teflon powder, zinc stearate powder, polyvinylidene fluoride powder; or cerium oxide. Powder, silicon carbide powder, strontium titanate powder and other abrasives; or carbon black powder, zinc oxide powder, tin oxide powder and other conductivity-imparting agents; white particles of opposite polarity and black particles improve developability. A small amount can be used as an agent.

The type of the binder resin used in the present invention is, for example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene or the like, or a substitution product thereof; styrene-p-chlorostyrene copolymerization. Coal, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile- Styrene-based copolymers such as indene copolymers Combined; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin , Polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. A crosslinked styrene resin is also a preferable binder resin.

Examples of the comonomer for the styrene monomer of the styrene type copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Didecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof;
For example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and substituted products thereof; for example, vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate and the like. Ethylene olefins such as ethylene, propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone;
For example, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and the like; and vinyl monomers such as are used alone or in combination.

As the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used. For example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene, etc .; for example, ethylene glycol diacrylate. , Ethylene glycol dimethacrylate,
A carboxylic acid ester having two double bonds such as 1,3-butanediol methacrylate; a divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and a compound having three or more vinyl groups. It can be used alone or as a mixture.

The binder resin used in the toner of the present invention is required to satisfy the fixing property, developing property, cleaning property and durability. From this aspect, the molecular weight distribution of the THF soluble component by GPC is 100,000 or more. Ingredients (THF
It is preferable that the content of insoluble gel is 5 to 60% by weight, especially 10 to 50% by weight based on the binder resin. When the content of the above components is less than 5%, problems such as durability of the developer and filming tend to occur, and when it exceeds 60%, problems such as fixability and damage to the photoreceptor tend to occur. The THF insoluble content of the binder resin in the present invention was measured by the following method.

The resin composition to be measured was passed through a 24 mesh pass,
As a powder of 60 mesh on, about 0.5 g was precisely weighed and cylindrical filter paper (Toyo filter paper No. 86R: diameter 28 mm, length 10
0 mm), 200 ml of THF was refluxed at a rate of about once every 4 minutes to extract the insoluble matter, and after sufficient drying, the weight was measured. The molecular weight distribution was measured by the following method.

Shodex as a column for GPC measurement
Using KF-80M, it was installed in a 40 ° C heat chamber of a GPC measuring device (150 CALC / GPC manufactured by Waters Co., Ltd.), a THF flow rate was 1 ml / min, and a detector was a sample under the conditions of RI (the concentration of the THF soluble component was about 1%). 0.1% by weight)
GPC was measured by injecting 200 μl of As a calibration curve of the molecular weight distribution, the molecular weight is 0.5 × 10 ³ , 2.35.
X10 ³ , 10.2 x 10 ³ , 35 x 10 ³ , 110 x 1
0 ³ , 200 × 10 ³ , 470 × 10 ³ , 1200 × 1
0 ^3, T of ^{2700 × 10 3, 8420 × 10} 3, in 10 monodisperse polystyrene standard substance (Waters Corp.)
It was prepared using an HF solution.

In the developer of the present invention, a charge control agent can be used by blending it with developer particles (internal addition) or by mixing it with developer particles (external addition). The charge control agent makes it possible to control the optimum charge amount according to the developing system, and particularly in the present invention, the balance between the particle size distribution and the charge amount can be further stabilized. The following substances control the toner to be positively charged. Modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and onium such as phosphonium salts which are analogs thereof. Salts and lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, and ferricyanide (Russian compounds, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyltin volley. Diorgano tin borate such like; may be used in combination singly or two or more kinds. Further, there are the following substances for controlling the toner to be negatively charged. For example, organic metal complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The above charge control agents are preferably used in the form of fine particles, and in this case, the number average particle diameter of these charge control agents is preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the developer, they are preferably used in an amount of 0.1 to 20 parts by weight, particularly 0.2 to 10 parts by weight, based on 100 parts by weight of the binder resin.

The colorant used in the toner of the present invention may be any appropriate pigment or dye. For example, as the pigment, carbon black, titanium black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, red iron oxide, phthalocyanine blue, indanthrene blue and the like can be used. These are used in an amount necessary and sufficient to maintain the image density of the copied image.
0.1 to 30 parts by weight, preferably 0.2
~ 20 parts by weight is good. A dye is used for the same purpose. For example, there are azo dyes, anthraquinone pigments, xanthene dyes, methine dyes, etc.
0.1 to 20 parts by weight, preferably 0.3
10 to 10 parts by weight is preferable.

As the carrier used in the developer of the present invention, known carriers can be used. For example, magnetic particles such as iron powder, ferrite powder, nickel powder and magnetite powder, or the surface of these magnetic particles can be treated with a fluororesin. Examples thereof include those treated with a vinyl resin, a silicone resin, or the like, or magnetic particle-dispersed resin particles in which magnetic particles are dispersed in the resin. The average particle size of these magnetic carriers cannot be unconditionally determined depending on the magnetic properties of the carrier particles, the toner concentration, and the like, but is 5 to 250 μm, preferably 10 to 20
0 μm, and more preferably 15 to 100 μm. 5
If it is less than μm, the carrier particles tend to adhere to the photosensitive member, and if it exceeds 250 μm, the toner of the present invention is not sufficiently charged and the surface of the photosensitive member tends to be scratched. The average particle size of the carrier was randomly extracted by 300 or more with an optical microscope, and the carrier particle size was determined by using the horizontal Feret diameter by the image processing analyzer Luzex3 manufactured by Nireco.

As an example of the method for producing the two-component developer according to the present invention, first, the above-mentioned binder resin, pigment or dye as a colorant, charge control agent, lubricant, other additives and the like are added to a Henschel mixer. After sufficiently mixing with a mixer such as the above, the constituent materials are well kneaded using a heat kneader such as a heating roll, a kneader and an extruder, and after cooling, a toner is obtained by mechanical pulverization and classification. Next, there is a method in which the hydrophobic inorganic fine powder and the toner are sufficiently mixed with a mixer such as a Henschel mixer, and finally the above-mentioned magnetic carrier is mixed with a predetermined mixing ratio to obtain a developer.

FIG. 2 is a schematic view of an image forming apparatus to which the developer of the present invention can be preferably applied. In FIG. 2, reference numeral 100 denotes an OPC belt photosensitive member having an OPC photosensitive layer provided on a conductive substrate, around which a primary charger 117, a developing device 140, a transfer charger 114, a brush cleaner 116, a register roller 124, etc. are provided. Has been. The photoconductor 100 is charged by the primary charger 117, and then the document exposure device 1
21 is exposed by irradiating the photoconductor 100 with the optical image of the original. The electrostatic latent image on the photoconductor 100 is developed with a two-component developer by the developing device 140, and the developed toner image on the photoconductor is transferred onto the transfer material by the transfer charger 114. The transfer material bearing the toner image is conveyed to a fixing device (not shown) by a conveyor belt (not shown) or the like, and is fixed on the transfer material. After the transfer, the untransferred toner particles slightly left on the photosensitive member and the paper dust and the filler generated from the transfer material are cleaned by the brush cleaner 116, and the collected foreign matters such as toner and paper dust are not shown in the collection container. Carried to. The two-component developer in the developing device 140 is controlled by a toner concentration control device (not shown) so that the toner concentration is within a certain range, and toner is supplied from a toner hopper (not shown).

[0061]

EXAMPLES The present invention will be specifically described below with reference to production examples and examples, but the present invention is not limited thereto. All parts in the following formulations are parts by weight.

(Production Example 1) Styrene-n-butyl acrylate copolymer 100 parts (containing 25% by weight of a molecular weight of 100,000 or more) Positive charge control agent (nigrosine compound) 2 parts Low molecular weight polypropylene (Mw = 6000) 3 parts 10 parts of carbon black (average particle size 60 nm)

After thoroughly stirring and mixing the above mixture with a Henschel mixer, the mixture was melt-kneaded with a twin-screw extruder heated to 140 ° C., the kneaded product was cooled and coarsely pulverized with a hammer mill, and the coarsely pulverized product was jet-milled. It was finely pulverized, and the obtained finely pulverized product was classified by wind force to obtain positively charged fine particles. Hydrophobic silica fine powder to 100 parts of these fine particles (amino group-containing silicone oil treated BET value 200 m ² / g)
The mixture containing 0.8 parts was mixed with a Henschel mixer to obtain a toner (1). Table 1 shows the particle size distribution of this toner (1).

Next, a developing agent (1) was obtained by sufficiently mixing 5 parts of toner (1) and 95 parts of silicone-based resin-coated copper-zinc-iron ferrite particles (average particle size 65 μm).

(Production Example 2) Styrene-2 ethylhexyl acrylate-maleic acid n-butyl half ester copolymer 100 parts (containing 55% by weight of a molecular weight of 100,000 or more) Positive charge control agent (triphenylmethane dye) 2 parts Low molecular weight polypropylene (Mw = 6000) 3 parts Carbon black (average particle size 60 nm) 15 parts

Using the above components in the same manner as in Production Example 1, positively chargeable magnetic fine particles were obtained. Hydrophobic silica fine powder (aminosilane coupling agent treated BE
Toner (2) was obtained by mixing 1.8 parts of T value of 200 m ^{2 /} g) with a Henschel mixer. The particle size distribution of Toner (2) is shown in Table 1. Next, a developer (2) was obtained by sufficiently mixing 3 parts of the toner (2) and 97 parts of the fluorine-acrylic resin-coated iron powder (average particle diameter 45 μm).

(Production Example 3) Toner formulation was a cross-linked polyester-containing styrene-n-butyl acrylate copolymer 100 parts (containing 45% by weight of a molecular weight of 100,000 or more) Positive charge control agent (triphenylmethane dye) 2 parts Low Molecular weight polypropylene (Mw = 6000) 3 parts Carbon black (average particle size 60 nm) 15 parts

A toner (3) was obtained in the same manner as in Production Example 1 except that the particle size distribution of the toner and the amount of the inorganic fine powder were changed as shown in Table 1. Next, a developer (3) was obtained by thoroughly mixing 4 parts of the toner (3) with 96 parts of the silicone-based resin-coated copper-zinc-iron ferrite particles (average particle size 55 μm).

(Production Example 4) Toner (4) was obtained in the same manner as in Production Example 2 except that the particle size distribution of the toner and the amount of inorganic fine powder were as shown in Table 1. Then, a developer (4) was obtained by sufficiently mixing 3 parts of the toner (4) and 97 parts of the magnetite particles (average particle size: 30 μm).

(Production Example 5) Toner (5) was obtained in the same manner as in Production Example 1 except that the particle size distribution of the toner and the amount of the inorganic fine powder were as shown in Table 1. Next, 4 parts of Toner (5) Silicone resin-coated copper-zinc-iron ferrite particles 96 parts (average particle size 65 μm) were sufficiently mixed to obtain a developer (5).

Production Example 6 Toner (6) was obtained in the same manner as in Production Example 1 except that the particle size distribution of the toner and the amount of inorganic fine powder were as shown in Table 1. Then, a developer (6) was obtained by sufficiently mixing 4 parts of the toner (6) with silicone resin-coated copper-zinc-iron ferrite particles (96 parts) (average particle size 50 μm).

(Production Example 7) Toner (7) was obtained in the same manner as in Production Example 1, except that the particle size distribution of the toner and the amount of inorganic fine powder were as shown in Table 1. Next, toner (7) 6 parts Fluorine-acrylic resin-coated iron powder 94 parts (average particle size 65 μm, saturation magnetization under 1 K oerstedt 65 emu / g) was sufficiently mixed to obtain a developer (7).

(Production Example 8) Toner (8) was obtained in the same manner as in Production Example 2 except that the particle size distribution of the toner and the amount of inorganic fine powder were as shown in Table 1. Then, a developer (8) was obtained by thoroughly mixing the toner (8) with 2 parts of the silicone resin-coated copper-zinc-iron ferrite particles with 98 parts (average particle size of 50 μm).

Production Example 9 Toner (9) was obtained in the same manner as in Production Example 2 except that the particle size distribution of the toner and the amount of the inorganic fine powder were as shown in Table 1. Then, 10 parts of Toner (9), 90 parts of fluorine-acrylic resin-coated iron powder (average particle diameter of 65 μm, saturation magnetization under 1 K Oersted 65 emu / g) were sufficiently mixed to obtain a developer (9).

(Production Example 10) Toner (10) was obtained in the same manner as in Production Example 1, except that the particle size distribution of the toner and the amount of the inorganic fine powder were as shown in Table 1. Then, a developer (10) was obtained by sufficiently mixing 3 parts of the toner (10) and 97 parts of the silicone-based resin-coated copper-zinc-iron ferrite particles (average particle size 50 μm).

(Production Example 11) Toner (11) was obtained in the same manner as in Production Example 1 except that the particle size distribution of the toner and the amount of inorganic fine powder were as shown in Table 1. Next, 5 parts of Toner (11) and 95 parts of silicone-based resin-coated copper-zinc-iron ferrite particles (average particle size of 65 μm) were sufficiently mixed to obtain a developer (11).

Example 1 A photoconductor was prepared by the following procedure. A conductive layer having a thickness of 30 μm in which conductive titanium oxide is dispersed in a phenol resin is provided on a polyamide resin film, and a charge generation layer made of a disazo pigment and a butyral resin has a dry film thickness of 0.
It was applied by the dipping method so as to have a thickness of 2 μm. Next, 45 wt% of a fluorene compound as a charge transport material and 55 wt% of a polycarbonate resin are dissolved in a benzene solvent, and this is applied onto the charge generation layer to a dry film thickness of 25 μm to form a charge transport layer. An OPC belt photoreceptor was provided.

Then, as an electrostatic latent image on the OPC belt photosensitive member, a dark portion potential of -700V, a light portion potential of -200V,
Halftone potential of -350V is formed, and linear velocity of photoconductor is 5
When the developing bias was set to 00 mm / sec, a developing bias DC-400 V was applied to the developing cylinder, and the developing agent (1) was used for developing, transferring, and cleaning (the transfer paper was white recycled paper EW500: A4 size).
Even after, 000,000 sheets, a clear image without scattering was obtained. The reproducibility of fine lines at this time was also sufficient. The results of Example 1 are shown in Table 2.

The amount of fogging is measured by a reflection type densitometer (TOKYO D
ENSHOKU CO. , LTD. REFLECT
OMETER MODEL TC-6DS was used to measure (the worst value of the reflection density of the white background after copying is Ds, and the average value of the reflection density of the paper before copying is Dr. Ds-Dr is the fog amount. % Or less is a good image with substantially no fog, and more than 5% is an unclear image with remarkable fog.)

In the present invention, the resolution is measured by the following method. That is, in a pattern composed of five fine lines having the same line width and spacing, a pattern of 3.
6, 4.0, 4.5, 5.0, 5.6, 6.3, 7.
An image obtained by copying an original document drawn with 1, 8.0, 9.0, and 10.0 lines under appropriate copying conditions is observed with a magnifying glass, and fine lines are clearly separated. The number of images (line / mm) is used as the value of resolution. The larger this number is, the higher the resolution is.

Example 2 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (2) in Example 1, and good results were obtained. The results are shown in Table 2.

Example 3 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (3), and good results were obtained. The results are shown in Table 2.

Example 4 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (4) in Example 1, and good results were obtained. The results are shown in Table 2.

Example 5 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (5) in Example 1, and good results were obtained. The results are shown in Table 2.

Example 6 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (6) in Example 1, and good results were obtained. The results are shown in Table 2.

Example 7 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (7) in Example 1, and good results were obtained. The results are shown in Table 2.

Example 8 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (8) in Example 1, but slight filming occurred, but practically OK. It was a level.
The results are shown in Table 2.

Example 9 In Example 1, the photosensitive member linear velocity was set to 750 at 500 mm / sec.
Good results were obtained when the same procedure as in Example 1 was carried out except that the value was set to mm / sec. The results are shown in Table 2.

Example 10 In Example 2, the linear velocity of the photosensitive member was set to 750 at a linear velocity of 500 mm / sec.
Good results were obtained when the same procedure as in Example 2 was carried out except that the value was set to mm / sec. The results are shown in Table 2.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (9) in Example 1, but the image density and the reproducibility of fine lines were insufficient. . The results are shown in Table 2.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (10) in Example 1. As a result, a large amount of fogging occurred and the image was unclear, and cleaning failure occurred. Occurred. The results are shown in Table 2.

Comparative Example 3 The same procedure as in Example 1 was carried out except that the developer (1) was changed to the developer (11) in Example 1. As a result, toner scattering between the lines was observed and the resolving power of the fine line was not good. It was enough. The results are shown in Table 2.

[0093]

[Table 1]

[0094]

[Table 2]

[0095]

As described above, according to the present invention,
Images with high image density, high resolution, and high-definition reproducibility, which are true to latent images and have virtually no fog, can be obtained.Furthermore, even in high-speed mass copying and long-term use, accumulation of coarse toner particles in the developer and exposure to light It is possible to obtain high image density, high resolution, and high-definition copied images with less body abrasion, prevention of cleaning failure and filming.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of an OPC photosensitive member used in the present invention.

FIG. 2 is a schematic diagram of an image forming apparatus of the present invention.

FIG. 3 is a diagram showing a range of a content ratio of particles of 5 μm or less in the toner according to the present invention.

[Explanation of symbols]

 100 Photoreceptor 114 Transfer Charger 116 Brush Cleaner 117 Primary Charger 121 Original Exposure Device 124 Register Roller 140 Developer

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G03G 15/08 507 L 15/09 Z 21/10 21/00 352 G03G 21/00 314

Claims (6)

[Claims] 1. Transfer means for forming a latent image on a moving or rotating latent image carrier, developing the latent image with toner, and transferring the developed toner image from the latent image carrier to a support surface. In a two-component developer having a magnetic carrier and a toner, which is used in a copying machine including a cleaning device for removing residual toner and foreign matters from a latent image carrier, the toner is composed of at least a binder resin and a colorant. Becomes
The weight average particle diameter of the toner is 4 to 8.5 μm and is 5 μm.
The following toner particles are contained in an amount of 17 to 80% by number and 6.3
5 to 70% by number of toner particles of 5 to 10.08 μm are contained, 2.0 vol% or less of toner particles of 12.7 μm or more are contained, and toner particles of 5 μm or less are represented by the following formula: N / V = −0.05N + k (In the formula, N represents the number% of toner particles of 5 μm or less,
V represents the volume% of the toner particles of 5 μm or less, and k is 4.
A positive number of 6 to 6.7 is shown. ) Is satisfied, a two-component developer. 2. The two-component developer according to claim 1, wherein the latent image carrier is an OPC belt photoreceptor. 3. The two-component developer according to claim 1, wherein the cleaning unit is a brush cleaning system using a rotating brush for a roll toner disturber. 4. A transfer for forming a latent image on a moving or rotating latent image carrier, developing the latent image with a two-component developer, and transferring the developed toner image from the latent image carrier to a supporting surface. Means and
An image forming method including a cleaning unit for removing residual toner and foreign matter from a latent image carrier, wherein the two-component developer has a magnetic carrier and a toner, and the toner is composed of at least a binder resin and a colorant. The toner has a weight average particle size of 4 to 8.5 μm, contains 17 to 80% by number of toner particles of 5 μm or less, and 6.35 to 1
5 to 70% by number of 0.08 μm toner particles are contained,
The toner particles of 12.7 μm or more are contained in an amount of 2.0 vol% or less, and the toner particles of 5 μm or less are represented by the following formula N / V = −0.05N + k (wherein, N represents the number% of the toner particles of 5 μm or less,
V represents the volume% of the toner particles of 5 μm or less, and k is 4.
A positive number of 6 to 6.7 is shown. ) Is satisfied, an image forming method characterized by satisfying. 5. The image forming method according to claim 4, wherein an OPC belt photosensitive member is used as the latent image carrier. 6. The image forming method according to claim 4, wherein the cleaning means is a brush cleaning system using a rotating brush for a toner toner disturber.