JP2614477B2 - Positively chargeable toner composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a toner used as a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like. More specifically, in a direct or indirect electrophotographic development method, a uniform and strongly positively charged image is provided by visualizing a negative electrostatic image or visualizing a positive electrostatic image by a reversal phenomenon to provide a high quality image. It relates to a positively chargeable toner.

BACKGROUND ART Conventionally, as electrophotography, U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910 (U.S. Pat.No. 3,666,363), and Japanese Patent Publication No. 43-24748 (U.S. Pat.
Numerous methods are known, for example, Japanese Patent Application Laid-Open No. 61 (1994). This electrophotographic method generally uses a photoconductive substance, forms an electric latent image on a photoreceptor by various means, and then develops the latent image using a developing powder (hereinafter referred to as toner). If necessary, a toner image is transferred to a transfer material such as paper, and then fixed by a heat, pressure, pressure and heat fixing roller or solvent vapor to obtain a copy. In the case where a step of transferring a toner image is provided, a step for removing residual toner on the photoconductor is usually provided.

A developing method for visualizing an electric latent image using toner is as follows.
For example, a magnetic brush method described in U.S. Pat.No. 2,874063, a cascade developing method described in 2,618,552 and a powder cloud method described in 2,221,776, U.S. Pat. A method using a conductive magnetic toner described in the specification of 3,909,258 has been proposed.

As a developing method using a high-resistance magnetic toner, a developing method utilizing the dielectric polarization of toner particles has been proposed. Further, in Japanese Patent Application Laid-Open No. 55-18656, etc., a very thin magnetic toner is coated on a sleeve, A method has been proposed in which triboelectric charging is carried out, and then this is brought very close to the electrostatic image and developed without facing the electrostatic image.

A method of similarly developing using a non-magnetic one-component toner is also proposed in Japanese Patent Application Laid-Open No. 58-143360.

Conventionally, fine powders obtained by dispersing dyes and pigments in natural or synthetic resins have been used as toners applied to these developing methods. For example, particles obtained by finely pulverizing a dispersion of a colorant in a binder resin such as polystyrene to about 1 to 30 μm are used as toner. As the magnetic toner, a toner containing magnetic particles such as magnetite is used. In the case of a system using a so-called two-component developer, the toner is usually used by being mixed with carrier particles such as glass beads and iron powder.

Examples of the positive charge control agent used in such a toner for dry development include, for example, quaternary ammonium compounds and organic dyes, particularly basic dyes and salts thereof. Nigrosine salts and nigrosine are often positive charge developers. It is used as These are usually added to a thermoplastic resin, melt-dispersed by heating, finely pulverized, and adjusted to an appropriate particle size as needed, and used.

However, these charge control agents are liable to cause a decrease in charge controllability due to mechanical shock, friction, changes in temperature and humidity conditions, and the like.

Therefore, if a toner containing these as a charge control agent is used in a copying machine at a job site, the toner may be deteriorated during the durability as the number of times of copying increases.

Further, since it is extremely difficult to uniformly disperse these charge control agents in a thermoplastic resin, there is a problem that a difference occurs in a triboelectric charge amount between toner particles obtained by pulverization. I have.

For this reason, conventionally, various methods for more uniformly dispersing have been performed. For example, a basic nigrosine dye is used in the form of a salt with a higher fatty acid in order to improve compatibility with a thermoplastic resin.However, an unreacted fatty acid or a dispersion product of a salt often appears on the toner surface. Exposure causes contamination of the carrier or the toner carrier, causing a reduction in toner fluidity, fog, and a reduction in image density. Alternatively, in order to improve the dispersion of the charge control agent in the resin, a method of mechanically pulverizing and mixing the charge control agent powder and the resin powder in advance and then hot-melt kneading has been proposed. However, in reality, it is not possible to avoid the incomplete dispersion of the particles, and the charge uniformity sufficient for practical use has not yet been obtained.

In addition, amino groups are introduced into the binder resin by copolymerizing or graft-polymerizing a positively chargeable monomer such as dimethylaminoethyl methacrylate, and the binder resin itself is made to be positively chargeable, so that the toner is uniform. Attempts have been made to provide a high charge.

However, the positive chargeability of the binder resin as described above is not constant, and the magnitude of the frictional force and the establishment of friction between the toner particles, between the toner and the carrier, or between the toner and the toner carrier such as the sleeve. And it is extremely difficult to always give a constant and stable positive charge to the toner. Therefore, when the appropriate friction is not obtained, the positive charging property of the toner is very unstable,
A copy image obtained with the toner is an image with much fog and scattering. On the other hand, if excessive friction is applied, the amount of positively charged electric charges on the toner surface becomes extremely large, and only an image having a large amount of roughness and a low density can be obtained.

Conventionally, inorganic fine powders contained in toner include titanium oxide, alumina, ferrite, red iron, colloidal silica, barium titanate, calcium titanate, clay, chromium oxide, cerium oxide, strontium titanate, and magnesium oxide. , Zirconium oxide and the like are known, and JP-A-52-135739 or JP-B-53-22377 discloses that a metal or metal oxide fine powder treated with aminosilane is contained in a toner. Means for obtaining a positively chargeable toner having stable chargeability are known.

The present inventors examined such a method in detail,
Using various aminosilane compounds, for example, colloidal silica, alumina, titanium dioxide, zinc oxide, iron oxide, γ
-When ferrite, magnesium oxide, etc. are treated to obtain a developer according to the examples described in the specification, it is difficult to obtain a developer exhibiting practically sufficient characteristics in any combination. Yes, it turned out to have some drawbacks.

That is, it is difficult for many developers to maintain desirable characteristics for faithfully reproducing a latent image, and to exhibit desirable performance at an early stage. It cannot be held and becomes unusable. That is, fogging occurs, toner scatters around the edge in copying a line drawing, and the image density also decreases. As other disadvantages, when development and transfer are performed under high temperature and high humidity environmental conditions, image density is reduced, line images are scattered, white spots, fog, and the like are generated.

Another method for obtaining a positively chargeable developer is disclosed in JP-A-59-201063. This is a method in which a fine silica powder treated with a silicone oil containing an amine in a side chain is contained as a component of the developer instead of the fine metal powder treated with the aminosilane described above. By this method, it is possible to compensate for the above-mentioned disadvantages of the developer containing the fine metal powder treated with aminosilane,
In analog development with sufficient potential contrast, a developer exhibiting practically sufficient characteristics can be obtained due to improvement in moisture resistance and stability of charging.

However, recently, as the demand for improving the image quality of an electrophotographic printer using a digital signal as an image signal increases, when a conventional negatively-chargeable toner is used, the toner is charged between toner particles or between the toner and the toner. The non-uniformity of the amount of charge easily generated on the surface of the toner particles between the carriers and between the toner carrier such as the toner and the sleeve causes a particular problem when imagining an electrostatic latent image formed by a digital image signal. It has become apparent that toner having a more uniform charge is needed.

When the image signal is a digital signal, the latent image is formed by collecting dots of a constant potential, and the solid portion, the halftone portion, and the light portion are each represented by changing the dot density. Therefore, when any part is binary, it is basically formed from an electrostatic latent image having substantially the same potential. Furthermore, recently, there has been an increasing demand for image quality improvement, and it has become necessary to improve the tone reproducibility by using a multi-valued dithering method based on a ternary or quaternary dithering method from the binary dithering method described above. This multi-valued dither method is liable to occur in highlights, so when removing contours or simultaneously reproducing an image in which halftones and line images are mixed, the matrix size of one pixel can be reduced without degrading the gradation. It is also an indispensable technique when the image quality is improved by reducing.

The concept of the dither matrix in the multi-value dither method will be described with reference to FIGS. 1 (a) and 1 (b). FIG. 1A is a 2 × 2 ternary dither matrix. Areas S ₁ , S ₂ , and S ₃ represent ternary density levels of white, gray, and black, respectively. FIG. 1 (b) shows 2 ×
This is a 4-valued dither matrix of 2 and includes areas S ₁ , S ₂ ,
S ₃ and S ₄ are white, light gray, dark gray, and black, respectively.
It represents the density level of the value. Dot size
16 bits / mm.

FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b)
Exposure density distribution when performing ternary recording in an optical scanning type electrophotographic printer (FIGS. 2 (a) and 3 (a))
And the corresponding potential distribution of the electrostatic latent image (FIGS. 2 (b) and 3 (b)). Second
3 (a) and 3 (a) show signal outputs for outputting a light beam for forming a multi-valued latent image, and FIG. 2 (a) shows the luminance for controlling the laser output. is gray level (hereinafter referred to as "M" level), to obtain a black level corresponding to S ₃ (hereinafter referred to as "H level") scheme, which corresponds to S ₂ of FIG. 1 by the modulation (a) . For example, the M level is obtained with a laser output that is 1/2 of the H level. On the other hand, FIG. 3A shows a method of obtaining M level and H level by pulse width modulation for controlling the laser output time. This is obtained, for example, by setting the M level to have a pulse width that is 1/2 of the H level.

The potential distribution of the latent image by the light beam having the exposure intensity distribution shown in FIGS. 2 (a) and 3 (a) is as shown in FIGS. 2 (b) and 3 (b), respectively. The M-level latent image contrast due to the pulse width modulation shown in FIG. 3B tends to be smaller than the H level due to a decrease in the MTF (modulation transfer function) of the latent image. Therefore, the image density after the development at the M level is almost the same gray as the image density at the M level in FIG.

Developing characteristic when Fig. 4 for developing the multi-valued latent image (V _S -
Indicates a D _P characteristics), FIG. 2 (b) and FIG. 3 (b)
In order to reproduce the M-level and H-level latent images (the respective potential contrasts are represented by), particularly when the H level cannot be sufficiently high, a relatively gamma (latent image potential) is used.
Image density D _P slope) is greater V _S -D _P characteristic for V _S (in the figure shown by a solid line) is required. However, when a conventional toner or developer for developing an analog latent image is used, in many cases, it tends to show development characteristics as shown by a solid line, in which case various problems such as a decrease in image density and sharpness are caused. .

Further, when the site of the latent image is expressed by the density of digital dots are precise control of the V _S -D _P curve is required as compared to conventional analog latent image. One slope of V _S -D _P curve to represent a digital latent image (gamma)
Must be made larger than before, and furthermore, it is necessary to control the inclination so as not to fluctuate. However, non-uniformity of the charge generated in the toner having a small particle size using a conventional charge control agent becomes an obstacle to increase the slope of V _S -D _P curves, also the inclination causes a state easy to change.

V _S when the inclination of -D _P curve is small, H-level dots are not reproduced in sufficiently high concentrations. If the difference between the H level and the M level cannot be sufficiently reproduced,
As shown in FIG. 3 and FIG. 3, the potential at the edge of the dot is lower than that at the center, causing problems such as poor image cutting at the end of the dot. As a result, the image density is low.
A defective image lacks in sharpness and has low resolution. In addition, the non-uniformity of the electric charge,
Or by variation of the use environment Kitaichi variation of V _S -D _P curve causing the above-mentioned problems.

Recently, the durability of OPC (organic photoconductor) drums has been improved, and cases have emerged in which positively chargeable toner is applied in a high-speed machine at a relatively low potential contrast. In this case, not only in the above-described digital development but also in the development of an analog latent image, a highly durable positively chargeable toner that can withstand a larger number of copies than before is required.

Further, image quality such as background fog, reverse fog, and rough fog tends to deteriorate in direct proportion to the increase in process speed, and is particularly remarkable in reverse fog. In this development, as the process speed increases, the chance of friction between the toner and the toner carrier is reduced and shortened.
This is presumed to be due to the fact that the toner cannot obtain sufficient and uniform charging.

In addition, by superimposing a large number of copies, a so-called selective development occurs in which toner having a uniform charge is preferentially used in the field, and as a result, image density decreases, image quality decreases, and reversal fog increases. Will result in various disadvantages not seen.

An object of the present invention is to provide a stable triboelectric charge amount between toner particles or between a toner and a carrier, between a toner and a toner carrier such as a sleeve in the case of one-component development, and a distribution of triboelectric charge amount. It is an object of the present invention to provide a positively chargeable toner which is sharp and uniform and can be controlled to a charge amount suitable for a developing system to be used.

Still another object is to provide a toner for performing development faithful to a digital latent image, that is, a slope of a VD curve at the time of development is large, and a difference in density between dots can be increased. An object of the present invention is to provide a toner whose part is reproduced sharply.

Still another object is to provide a toner that maintains its initial characteristics even when the toner is used continuously for a long period of time and has no fluctuation in the VD curve.

Still another object is to provide a toner that reproduces a stable image that is not affected by changes in temperature and humidity.

Still another object is to provide a toner having excellent storage stability that maintains initial characteristics even after long-term storage.

SUMMARY OF THE INVENTION As a result of intensive studies, the present inventor has found that, instead of imparting hydrophobicity to metal-containing fine particles by surface treatment as in the conventional method, the metal-containing fine particles are formed at the time of forming metal-containing fine particles by hydrolysis of an organometallic compound. It has been found that imparting hydrophobicity to the fine particles themselves is extremely effective in achieving the above object.

That is, the positively chargeable toner composition of the present invention contains toner particles containing at least a binder resin and a colorant, and metal-containing or silicon-containing fine particles, and the metal-containing or silicon-containing fine particles are hydrolyzable. Partially obtained by hydrolysis of a mixture of an organometallic or organosilicon compound (A) having only one group and an organometallic or organosilicon compound (B) having at least one non-hydrolyzable organic group. It is characterized in that it is a fine powder of an oxide or hydroxide of a metal or silicon with a hydrolyzable organic group remaining. In the method of imparting hydrophobicity to a metal such as silica or a silicon oxide by surface treatment as in the conventional method, according to the knowledge of the present invention, it is difficult to uniformly treat the surface of silica or the like. It is presumed that many were in a state of being wrapped over the aggregates with a treating agent. In addition, considering that the aggregates are easily dispersed and the processing agent is likely to fall off due to the shear in the developing device, the uniform correctness is obtained under severe conditions such as high temperature and high humidity, high speed machine and digital machine. It is difficult to maintain chargeability and hydrophobicity,
During the equipment life of 100,000 to several million sheets,
It is estimated that troubles such as increased fog were likely to occur.

On the other hand, in the toner composition of the present invention, the metal-containing or silicon fine particles themselves formed by hydrolysis of the organic metal or silicon compound are imparted with hydrophobicity, and the organic group as a hydrophobic group is added to the fine particles. Because it remains in the structure of, even if the aggregates are dispersed by the shear,
Hydrophobicity does not decrease as in the conventional method, and the instability due to the hydrophobicity imparted by the surface treatment in the conventional method can be eliminated. Therefore, in the present invention, it is presumed that a toner capable of maintaining uniform positive chargeability and hydrophobicity even under the above-mentioned severe conditions can be obtained by mixing the fine powder with the toner.

Hereinafter, the present invention will be described in more detail with reference to the drawings as necessary. In the following description, “%” and “parts” representing the quantitative ratios are based on weight unless otherwise specified.

DETAILED DESCRIPTION OF THE INVENTION The toner composition of the present invention hydrolyzes toner particles containing at least a binder resin and a colorant (used for the purpose of including a magnetic material) and two specific organometallic or silicon compounds. And metal-containing or silicon fine particles having an organic group remaining on at least the surface thereof.

In the present invention, the organometallic or silicon compound refers to a compound containing a metal or silicon and at least one organic group bonded to the metal or silicon.

In the present invention, the metal-containing or silicon fine powder comprises an organic metal or silicon compound (A) in which all the groups bonded to the metal or silicon are hydrolyzable groups (hereinafter referred to as “active groups”); Alternatively, it can be obtained by hydrolysis of a mixture with an organic metal or silicon compound (B) containing at least one organic group which is not hydrolyzed and bonded to silicon (hereinafter referred to as “inactive group”).

The fine powder obtained by hydrolysis of only an organic metal or silicon compound (A) containing only an active group is a mere inorganic metal or a fine powder of silicon oxide or hydroxide,
In the present invention, a compound (B) containing an organic group that is not hydrolyzed is also used as the organometallic or silicon compound, so that a hydrophobic organic inert group or a positively chargeable group ( Or both) are left, and a fine powder connecting stable chargeability and hydrophobicity can be contained in the toner.

The metal or silicon constituting the organometallic or silicon compound (A) or (B) is not particularly limited as long as the organometallic or silicon compound containing the active group can be synthesized. Al, Mn, Fe, Ni, Zn, Zr,
A compound containing metal or silicon such as Sn is preferable, and a compound containing Si is more preferable.

The metal or silicon constituting the compounds (A) and (B) may be different, but the same is preferred from the viewpoint that a uniform composition can be obtained.

As the active group contained in the organometallic or silicon compound (A), an organic active group such as an alkoxy group (preferably having 1 to 4 carbon atoms) or an acetylacetonate group is preferably used. One compound (A) may contain different active groups, or two or more of the above compounds (A) may be used in combination as necessary.

More specific examples of the organometallic or silicon compound (A) in the present invention include tetraisopropoxytitanium,
Ti compounds such as tetra-n-butoxytitanium, isopropoxytitanium triisostearate, isopropoxytitanium tri-N-ethylaminoethylaminate, diisopropoxybis (acetylacetonato) titanium; tetramethoxysilane, tetraethoxysilane, etc. Si compound;
Aluminum compounds such as aluminum acetylacetonate and triisopropoxy aluminum; tin compounds such as acetylacetone tin
Sn compounds; and the like are preferably used.

On the other hand, as the inert group contained in the organometallic or silicon compound (B), an organic group such as an alkyl group, an aryl group or an aralkyl group is preferably used. This compound (B)
Preferably has at least one active group, and more preferably has 2 to 3 active groups.

More specific examples of such a compound (B) include:
Si compounds such as trimethoxymethylsilane, dimethoxydimethylsilane and γ-aminopropyltrimethoxysilane; Sn compounds such as dibutyltin acetylacetonate;
Etc. are used brutally.

One compound (B) may contain different inactive groups or active groups, and the above compound (B) may be used in combination of two or more as necessary.

In order to obtain a stable positive charging property of the metal-containing or silicon fine particles in the present invention, the above-mentioned inactive group of the organic metal or silicon compound (B) contains a nitrogen-containing group in the middle or at the terminal of its molecular chain. Is preferred. The nitrogen atom in the nitrogen-containing organic group may be primary, secondary or tertiary, but is preferably a tertiary nitrogen atom from the viewpoint of improving hydrophobicity. Further, the nitrogen atom may be incorporated in a heterocyclic ring.

In the present invention, the organometallic or silicon compound (B)
It is preferable to use a combination of a compound containing no nitrogen-containing inactive group and a compound containing a nitrogen-containing inactive group in order to obtain a good balance between hydrophobicity and positive chargeability. In this case, the compound (B) containing a nitrogen-containing compound is preferably used in an amount equal to or less than the weight of the compound (B) containing no nitrogen-containing group.

In the present invention, it is possible to select any combination of the above compounds from the viewpoint of the type of the organic group desired to be left inside and on the surface of the fine powder and the hydrolyzability, and is not limited to the above compounds.

In the present invention, it is preferable to use 1 to 30 parts, more preferably 2 to 15 parts of a compound containing a nitrogen in an inert group, based on 100 parts of the total amount of the organic metal or silicon compound (A + B).

In the hydrolysis of the mixture of the compound (A) and the compound (B), it is preferable to use a so-called liquid phase method, in which fine particles comprising a metal or a silicon oxide or a metal or a silicon hydroxide are used in a liquid. It is more preferable to precipitate and grow in the liquid to obtain metal-containing or silicon fine particles.

The time of hydrolysis in the liquid in is preferably performed in advance is preferably used pure purged with an inert gas such as N _2, also under warming at about 40 to 80 ° C..

In the present invention, the metal-containing or silicon fine powder obtained by hydrolysis of the organometallic or silicon compound has a sharp particle size distribution and is close to monodisperse, and its function can be separated by changing its constituent unit and particle size. Has an average particle size of 1
It is preferable to prepare a positively chargeable hydrophobic fine powder having a particle size of not more than μm and to include it in the positively chargeable toner.

When the average particle diameter of the metal-containing or silicon fine powder is 5 μm or more, fogging is likely to occur in an image.

The application amount of the metal-containing or silicon fine powder synthesized by such hydrolysis is effective when the amount is 0.01 to 20% based on the weight of the developer, and is particularly preferable when 0.03 to 3% is added. A stable chargeability is obtained. In a preferred embodiment of the addition form, it is preferable that 0.01 to 5% by weight, based on the weight of the developer, of the synthesized metal-containing or silicon powder is attached to the surface of the toner particles.

Further, the metal-containing or silicon fine powder used in the present invention,
If necessary, the composition may be further treated with a silane coupling agent or a treating agent such as an organosilicon compound for the purpose of imparting hydrophobicity. As this treatment method, a known method may be used, and the treatment may be performed with the treatment agent that reacts or physically adsorbs with the metal-containing or silicon fine powder. Examples of such a treating agent include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, Bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxy Orchid, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3
Diphenyltetramethyldisiloxane, and dimethylpolysiloxane having from 2 to 12 siloxane units per molecule, and the terminal units each containing one hydroxyl group bonded to Si. These are used alone or in a mixture of two or more.

Examples of the coloring agent used in the present invention include carbon black, lamp black, iron black, ultramarine, aniline blue, phthalocyanine blue, phthalocyanine green, Hiza Yellow G, rhodamine 6G, lake, calco oil blue, chrome yellow, quinacridone, and benzidine. Conventionally known dyes and pigments such as yellow, rose bengal, triallylmethane dyes, monoazo dyes and disazo dyes can be used alone or in combination of two or more without any particular limitation.

The amount of the colorant used is 1 to 100 parts of the resin component.
It is preferably about 10 parts.

The toner of the present invention may further contain a magnetic material and be used as a magnetic toner. In this case, the magnetic material is
The coloring agent is used also as (all or part of) the coloring agent. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides such as magnetite, maghemite, and ferrite;
Metals such as cobalt and nickel or metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium And a ferromagnetic material comprising a mixture thereof.

These ferromagnetic materials preferably have an average particle size of about 0.1 to 2 μm, and are contained in the toner in an amount of preferably about 20 to 200 parts by weight, particularly preferably 100 to 100 parts by weight of the resin component. It is 40 to 150 parts by weight based on parts by weight.

As long as the toner of the present invention is not adversely affected, it can be used in combination with a conventionally known charge control agent.

Examples of the binder resin used in the present invention include styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyl toluene, and a homopolymer of a substituted product thereof; styrene-p
-Chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-
Copolymers of styrene represented by vinyl naphthalene copolymer and other vinyl monomers; styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene −
Styrene-acrylate copolymer represented by octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer; styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- Styrene-methacrylate copolymer represented by butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate, styrene-diethylaminoethyl methacrylate, styrene-dimethylaminopropyl methacrylate; 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 copolymers such as styrene-isoprene copolymer, styrene-acrylonitrile-indene-copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide,
Examples include epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like. These binder resins can be used alone or in combination of two or more.

As the binder resin particularly suitable for pressure fixing, the following resins can be used alone or in combination of two or more.

Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, poly-4-fluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio 5-30: 95-7)
0), olefin copolymer (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, Ethylene-vinyl acetate copolymer, ionomer resin), polyvinyl pyrrolidone, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, and phenol-modified terpene resin.

When used as a two-component developer, the toner of the present invention is used by mixing with a carrier powder.

As the carrier that can be used in the present invention, all known carriers can be used, for example, iron powder, ferrite powder,
Examples include magnetic powder such as nickel powder, glass beads and the like, and those obtained by treating the surface of the powder with a resin or the like.

Further, in the toner of the present invention, more results can be obtained when additives are used or mixed as needed. Examples of the additive include a lubricant such as Teflon and zinc stearate, or an abrasive such as cerium oxide and silicon carbide; a fluidity imparting agent such as colloidal silica and aluminum oxide; a caking inhibitor; There are a conductivity-imparting agent such as tin and a fixing aid such as low-molecular-weight polyethylene.

In order to produce the electrostatic image developing toner according to the present invention,
The above-mentioned vinyl-based or non-vinyl-based thermoplastic resin and a pigment or dye as a colorant (and / or a magnetic material as necessary), additives, etc. are sufficiently mixed by a ball mill or other mixer, and then heated roll, kneader Melting, kneading and kneading using a heat kneading machine such as an extruder, dispersing or dissolving the pigments or dyes in the resins mutually compatible, pulverizing and classifying after cooling and solidifying, and averaging Particle size 5-20μ
m of toner can be obtained.

The above-mentioned metal-containing or silicon fine particles are preferably added by mixing with toner particles (so-called external addition),
In particular, it is preferable to perform the mechanical mixing. A known method can be applied as such a mechanical mixing method. For example, V-type mixer, Nauta mixer, turbula mixer,
A commercially available device such as a corn blender or a Henschel mixer can be applied.

Alternatively, a method of obtaining a toner by dispersing the material in a binder resin solution and then spray-drying, or polymerizing after mixing a predetermined material with a monomer to constitute the binder resin to form an emulsion suspension. A method such as a polymerization method of obtaining a toner by making the toner or a method of obtaining a capsule toner composed of a core and a shell can be applied.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. All parts in the following formulations are parts by weight.

EXAMPLES Synthesis Examples The synthesis of the silica according to the present invention was performed as follows, but this does not limit the present invention in any way.

1,000 g of pure water was precisely weighed into a four-necked round bottom flask of No. _{2 and} purged with N ₂ while stirring.

During this time, the temperature of the flask was raised to 60 ° C. in a thermostat and maintained.

Separately, after the above components were uniformly mixed in one beaker, the mixture was gradually dropped into the pure water using a dropping funnel while stirring. When silica starts to precipitate from the mixture,
The remaining amount was added dropwise at a time, and stirring was further continued for 2 hours while maintaining the temperature at 60 ° C.

This silica was separated, dried using a vacuum drier, and then crushed to obtain silica fine powder A (metal-containing fine powder, average particle size 0.1 μm).

Example 1 After the above materials were mixed well in a blender, they were kneaded with two rolls heated to 150 ° C. The kneaded product is allowed to cool naturally, then coarsely pulverized with a cutter mill, pulverized using a fine pulverizer using a jet stream, and further classified using an air classifier to obtain a black fine powder having a number average particle size of 10 μm. Was.

 Fine powder A obtained in the above synthesis example (average particle size 0.1 μm)
Was added to 0.5 parts by weight based on 100 parts by weight of the black fine powder,
The mixture was mixed with a Henschel mixer to obtain a toner. Fine powder A
Against iron powder Was charged.

Applying this toner to an electrophotographic printer using amorphous silicon, image evaluation (image formation test)
Was performed.

FIG. 5 is a schematic side sectional view in the thickness direction of transfer paper as an example of an electrophotographic printer to which the toner composition of the present invention can be applied. Referring to FIG. 5, an electric signal input to laser modulation unit 1 is output as a modulated laser beam, and is scanned by scanner mirror 2 and f · θ lens 3 in the longitudinal direction of photosensitive drum 4 (drum rotation). (In the direction parallel to the axis). The photosensitive drum 4 rotates in the direction of the arrow, enabling two-dimensional scanning with the laser beam.

Photoconductors are amorphous silicon, selenium, Cd
S, an organic photoreceptor (OPC), or the like is used, and is sensitized to have a sensitivity to, for example, the wavelength of a semiconductor laser (780 nm to 800 nm). In this embodiment, an amorphous silicon photoreceptor was used as such a photoreceptor, and the potential of the photoreceptor surface was leveled by an AC neutralizer 5 and then charged to 380 V by a charger 6. Thereafter, laser beam exposure was performed to form a dot latent image on the photosensitive member by a ternary dither method by an image scanning method. The three M levels were formed by pulse width modulation of the laser light as shown in FIG. 3 (a). The latent image potential was 250 V at the H level and 120 V at the M level.

Such a dot latent image was reversely developed by a developing device 9 or 10 containing a developer containing the above-mentioned toner. At this time, a developing bias of 280 V was applied as a DC component.

The image thus developed is then transferred onto a transfer paper 12 by a transfer charger 11, and is then transferred by a fixing device 13 to the transfer paper 12.
It was established in. The toner remaining on the photosensitive drum 4 without being transferred was collected by the cleaner 14.

The image formed on the transfer paper in this manner shows an image density of 1.30 at the H level and 0.65 at the M level, has a sufficiently high solid image density, sharp dots, and reproduces halftones. The photographic image as a guide was also reproduced beautifully. In addition, 10,000 copies were repeated, but in the obtained image density, the fluctuation of the H level was within ± 0.07,
Variation of M levels is within ± 0.10, significant changes in V _S -D _P characteristic was observed.

Furthermore, when the environmental conditions were set to 35 ° C., 85%, 15 ° C., and 10%, good images were obtained as in the case of room temperature and normal humidity, and these changed significantly even when 10,000 sheets were repeatedly used. Did not.

When this developer was stored at 23.5 ° C. and 60% RH for half a year, no significant change was observed from the initial characteristics.

No increase in reversal fog was observed during the above durability.

Examples 2 to 4 Fine powder A of Synthesis Example 1 except that the following components were used, respectively.
The fine powders B, C, and
And D were obtained. A toner was prepared and images were formed in the same manner as in Example 1 except that the fine powders B, C, and D were used instead of the fine powder A used in Example 1.

The results obtained are shown in Table 2 below.

Further, when the environmental conditions were set to 35 ° C., 85%, 15 ° C., and 10%, good images were obtained as in the case of normal temperature and normal humidity, and no change was observed in practical use even when 10,000 sheets were repeatedly used. Was.

Also, no increase in reversal fog was observed during the durability.

Example 5 In place of the styrene-butyl methacrylate copolymer used in Example 1, a styrene-butyl methacrylate-dimethylaminoethyl methacrylate copolymer (weight ratio 7: 2.
5: 0.5, Mw = 250,000), and the image formation was evaluated in the same manner as in Example 1.

The obtained image showed 1.39 at the H level and 0.64 at the M level. The solid image density was sufficiently high, the dots were sharp, and the photographic image as a standard for reproducing halftones was reproduced clearly.

The 10,000 sheets but copy is carried out repeatedly, in the image density, the variation of H-level is ± 0.07 within the variation of M levels is within ± 0.15, no practical change was observed in the V _S -D _P characteristics Was. Further, when the environmental conditions were set to 35 ° C, 85%, 15 ° C, and 10%, good images were obtained as in the case of normal temperature and normal humidity, and these changed practically even when 10,000 sheets were repeatedly used. Did not.

In addition, no increase in reversal fog was observed during the durability.

Example 6 A toner was prepared in the same manner as in Example 1 except that 50 parts of γ-iron oxide was used instead of 60 parts of magnetite used in Example 1, and image formation evaluation was performed.

The density of the obtained sepia image is 1.38 at the H level and 0.65 at the M level. The solid image density is sufficiently high, the dots are sharp, and the photographic image as a guide for reproducing halftones is reproduced beautifully. Was done.

In addition, 10,000 copies were repeated, but the fluctuation of H level was within ± 0.07 and the fluctuation of M level was within ± 0.15.
Practically change in V _S -D _P characteristic was observed. Furthermore, when the environmental conditions were set to 35 ° C, 85%, 15 ° C, and 10%, good sepia images were obtained as in normal temperature and normal humidity, and these changed practically even when 10,000 sheets were repeatedly used. I couldn't.

Also, no increase in reversal fog was observed during the durability.

Example 7 The above materials were mixed well in a blender and kneaded with two rolls heated to 150 ° C. After naturally cooling the kneaded material, coarsely pulverized with a cutter mill, pulverized using a fine pulverizer using a jet stream, and further classified using an air classifier to obtain a particle size of 5 to 5.
A fine powder of 20 μm was obtained.

Next, 100 parts of the fine powder was added to the fine silica powder A0.4 of Example 1.
Parts, and mixed with a Henschel mixer to obtain a particle size of 50.
A developer was prepared by mixing 500 parts of magnetic particles having a size of 〜80 μm.

This developer was applied to a commercially available copying machine (trade name: PC-22, manufactured by Canon Inc.) to produce an image.

As a result, a bright blue image having an image density of 1.40 was obtained, there was no fog, and the sharpness of the image could be sufficiently satisfied. In addition, 2,000 copies were repeated, but the image density was 1.36, almost unchanged, and no reduction in image sharpness was observed.

Further, the copying environment was set to 35 ° C., 85% and 15 ° C., 10%, and in each case, a good image similar to normal temperature and normal humidity was obtained.

Example 8 Instead of the fine powder A used in Example 1, fine powder D 0.3%,
A toner was prepared and imaged in the same manner as in Example 1 except that a fine powder mixed with 0.2% of fine powder G treated with an amino-modified silicone oil (amine equivalent: 800) was used. Good results were obtained as in Example 1.

Example 9 The toner of the example was applied to a Canon NP-5540 copier to perform image formation.

The NP-5540 copier used here is a one-touch multiplex / two-color copier using OPC, employs a multi-stage developing unit, and erases a part of the electrostatic latent image on the drum using LEDs, fuse lamps, etc. And then insert another image into that part. In this copying machine, the drum potential (V _SL ) of the portion erased by the LED greatly decreases, and the difference | V _DC −V _SL | from the DC bias (V _DC ) at the time of development is smaller than that of a normal copying machine. Therefore, a toner having a large latitude, which is an allowable limit of reversal fog, is required.

Here, when the above V _DC is changed and the permissible limit V _DC of the reversal fog in the V _SL portion is V _DC ′, the result | V _DC ′ −V _SL | shows 300 V at the initial stage, and after the endurance of 50,000 sheets. , The reversal fog on the actual image was not observed at all.

In addition, the image density is 1.40 to 1.45 when outputting 50,000 sheets.
And was stable.

Example 10 The charge amount deterioration test was performed on both silica (fine powder A) used in the present invention and silica (fine powder G) whose dry silica surface was treated with amino-modified silicone oil as follows.

That is, iron powder carrier (EFV200 / 300 made by Nippon Iron Powder) /
Silica fine powder = Total mixture of 98/2 mixed 30
g was precisely weighed in a 100 cc wide-mouthed poly bottle and shaken with a turbula mixer for up to 4 hours. At each measurement time, about 1 g of the above mixture was sampled, and the triboelectric charge was measured to determine the degree of deterioration.

The measurement of the triboelectric charge amount in the present invention was 23.5 ° C., 60% RH
The test substance was mixed with an iron powder carrier having a particle size of 200/300 mesh (EFV200 / 300 above), and the mixture was precisely weighed to 0.5 to 1.5 g. On a connected metal 400 mesh screen, the silica fine powder was removed by suction at a pressure of 25 cmH ₂ O, and the weight of the test substance (silica fine powder) separated and sucked at that time was measured by the electrometer. Based on the charge amount, a method of obtaining the charge amount per unit weight of the test substance was used.

The results obtained above are shown in the graph of FIG.
Referring to FIG. 6, fine powder G showed a large decrease in charge amount, whereas fine powder A used in the present invention did not show any decrease in charge amount.

This is different from the case where the surface-treated fine powder G according to the conventional method is imparted with hydrophobicity by a simple surface treatment. In the case of the fine powder A obtained by hydrolysis of an organometallic or silicon compound, the fine powder itself is not used. Since the surface is imparted with hydrophobicity, even if agglomerates are peeled off or components on the surface are dropped, it has a characteristic that the initial chargeability is not lost.

Comparative Example 1 A toner was prepared in the same manner as in Example 1, except that the fine silica powder (specific surface area: 200 m ² / g) produced by a dry method was used as it was in place of the fine powder A used in Example 1. The image was obtained, but the obtained image was poor, at H level 0.27,
The concentration was 0.15 at the M level.

Comparative Examples 2 and 3 Toner was prepared and images were formed in the same manner as in Example 1 except that fine powders shown in Table 3 below were used instead of fine powder A used in Example 1. .

The results obtained above are shown in Table 4 below.

From these results, it can be understood that in Comparative Examples 2 and 3, although there is little problem in practical use, the H-level and M-level image density fluctuations are clearly larger than in Examples 1-4.

Further, when an image was formed under high temperature and high humidity of 30 ° C. and 85%, in Comparative Example 2, the image density was H level from the beginning.
The density was as low as 0.72, and after 10,000 copies, the density was significantly reduced to 0.32.

Comparative Example 4 An image was formed in the same manner as in Example 9 except that the toner of Comparative Example 2 was used instead of the toner of Example 1. As a result, a sufficient density of 1.35 was obtained at the initial stage, and | V _DC '. -V _SL | was 230V and had no effect on the actual image.

However, if you continue to produce images, about 10,000 copies of | V _DC '-V _SL |
Inverted fog started to be noticeable at 180V, and about 20,000 sheets | V
_DC '-V _SL | occurs inversion fog unacceptable equal to or less than 160V, concentration was also decreased to 1.15.

Effects of the Invention As described above, according to the present invention, by containing a metal-containing or silicon fine powder obtained by hydrolysis of a mixture containing two specific kinds of organic metals or silicon compounds, durability, environmental resistance A toner having excellent properties can be obtained.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are diagrams showing the concept of a multi-valued dither matrix, FIGS. 2 (a) and 2 (b) and FIGS.
(B) is a characteristic graph showing the exposure intensity distribution and the potential distribution of the electrostatic latent image when performing ternary recording, FIG. 4 is a graph showing the development characteristics of a multi-valued latent image, and FIG. FIG. 6 is a schematic side sectional view of a transfer paper in a thickness direction schematically showing a specific example of an electrophotographic printer to which a toner is applied. FIG. 6 is a graph showing the charge deterioration characteristics of the metal-containing or silicon fine powder used in the present invention. It is. 1 laser modulation unit, 2 scanner mirror, 3 f / θ lens, 4 photosensitive drum, 5 and 6 corona discharger, 9 first developing device, 10 second developing device vessel. Representative figure: Fig. 6

Claims (3)

(57) [Claims] An organic metal or organic material comprising toner particles containing at least a binder resin and a colorant, and metal-containing or silicon-containing fine particles, wherein the metal-containing or silicon-containing fine particles have only a hydrolyzable group. A non-hydrolyzable organic group remains in a part obtained by hydrolysis of a mixture of a silicon compound (A) and an organic metal or an organosilicon compound (B) having at least one non-hydrolyzable organic group. A positively chargeable toner composition, which is a fine powder of a metal or silicon oxide or hydroxide. 2. The positively chargeable toner composition according to claim 1, wherein the non-hydrolyzable organic group is a group containing at least one of a carbon atom and a nitrogen atom. 3. The positively chargeable toner composition according to claim 1, wherein the metal-containing or silicon-containing fine particles have an average particle size of 1 μm or less and are positively charged with respect to iron powder.