JPS62289853A - Toner for electrostatic photography - Google Patents

Abstract

PURPOSE:To stabilize triboelectrification quantities between toner particles themselves and between the toner and a toner carrying body and to render the distribution of the triboelectrification quantities sharp and uniform by incorporating bis(diorgano-tin-carboxylate)dicarboxylate. CONSTITUTION:The toner contains as a charge controller the bis(diorgano-tin- carboxylate)dicarboxylate represented by formula I, II, or the like. Known colorants and binders can be used for this toner, and this can be used for a pressure-fixing toner, and as one component type toner and also as binary developer, thus permitting the toner to be controlled to an electrification quantity suitable for the development system to be used and to maintain the initial characteristics even after uses for a long period by incorporating this compound.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a new toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Prior Art] Conventionally, various electrophotographic methods have been described in US Pat. No. 2,297,891, Japanese Patent Publication No. 42-23910, Japanese Patent Publication No. 43-24748, In short, a photoguide is used to apply a uniform electrostatic charge onto a conductive insulating layer, a light image is irradiated onto the insulating layer to form an electrostatic latent image, and the latent image is then transferred to a toner using the technique. The image is developed and visualized using a fine powder known as a powder, and if necessary, the powder image is transferred to paper or the like, and then fixed by heating, pressure, solvent vapor, or the like.

Development methods applicable to these electrophotographic methods include:
Broadly speaking, there are dry development methods and wet development methods. The former method is further divided into a method using a two-component developer and a method using a -component developer. Two-component developing methods include:
Magnetic brush method using iron powder carrier, beads and
There are a cascade method using a carrier, a fur brush method using fur, etc.

In addition, those belonging to the -component type development method include a powder cloud method in which toner particles are sprayed, and a contact development method (contact development, or (also called toner development), toner particles? 1) A jumping development method in which toner particles are charged and flown toward the latent image surface by the electric field of the electrostatic latent image without directly contacting the electrostatic latent image surface, and magnetic conductive toner is transferred to the electrostatic latent image surface. There is the MagneDry method, which develops the film by contacting it.

As toners applied to these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. For example, particles obtained by dispersing a colorant in a binder resin such as polystyrene and pulverizing the particles to about 1 to 30 μm are used as toner. As the magnetic toner, one 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 mixed with carrier particles such as glass beads and iron powder.

Further, the toner is made to have a positive or negative charge depending on the polarity of the electrostatic latent image to be developed.

In order to make the toner hold an electric charge, it is also possible to use the triboelectricity of the resin that is a component of the toner, but since the toner's chargeability is small with this method, the image obtained by development is prone to fogging and is unclear. Become something. Therefore, in order to impart desired triboelectrification properties to toners, dyes and pigments that impart electrostatic properties, as well as charge control agents, are added.

Charge control agents known in the art today include nigrosine, which controls toner to be positively charged;
Azine dyes, quaternary ammonium salts, dialkyl tin oxides, etc. are used to control the toner's negative chargeability, while metal complex salts of monoazo dyes, Go of salicylic acid,
Examples include metal complexes such as Cr and Fe.

These are usually added to thermoplastic resins, thermally melted and dispersed, and then finely pulverized and adjusted to a suitable particle size as necessary before use.

However, these dyes used as charge control agents have complex structures, inconsistent properties, and poor stability.They are also susceptible to decomposition during thermal kneading, mechanical shock, rubbing, changes in temperature and humidity conditions, etc. This tends to cause decomposition or deterioration, and a phenomenon of deterioration of charge controllability is likely to occur.

Therefore, when a toner containing these dyes as a charge control agent is used for development in a copying machine, as the number of copies increases, the charge control agent decomposes or changes in quality, which may cause deterioration of the toner during durability.

Furthermore, since it is extremely difficult to uniformly disperse these charge control agents in thermoplastic resins, they have the fatal drawback of causing a difference in the amount of frictional charge between toner particles obtained by pulverization. are doing. For this reason, various methods have been used to achieve more uniform dispersion. For example, basic nigrosine dyes are used by forming salts with higher fatty acids in order to improve their compatibility with thermoplastic resins, but often unreacted fatty acids or salt dispersion products are
It is exposed on the toner surface and contaminates the carrier or toner carrier, causing a decrease in the fluidity of the toner, fogging, and a decrease in image density. Alternatively, in order to improve the dispersion of these charge control agents into the resin, a method has also been adopted in which charge control agent powder and resin powder are mechanically pulverized and mixed in advance and then hot melt-kneaded. but,
The inherent poor dispersion cannot be avoided, and the current situation is that sufficient charge uniformity has not yet been obtained for practical use.

Moreover, most of the substances generally known as charge control agents have a dark color, and there is a problem in that they cannot be incorporated into bright chromatic color developers.

In addition, many charge control agents are hydrophilic, and due to poor dispersion in these resins, when pulverized after melt-kneading,
The dye is exposed on the toner surface.

Therefore, when using toner under high humidity conditions, these
Since the charge control agent is hydrophilic, it has the disadvantage that good quality images cannot be obtained.

In this way, when conventional charge control agents are used in toner,
Variations occur in the amount of charge generated on the surface of toner particles between toner particles, between toner and carrier, or between toner and a toner carrier such as a sleeve,
Problems such as development fog, toner scattering, and carrier contamination are likely to occur. Further, this failure becomes a noticeable phenomenon when copying is repeated many times, resulting in a result that is practically unsuitable for copying machines.

Furthermore, under high humidity conditions, the transfer efficiency of toner images decreases significantly, and many of them become unusable. Even at room temperature and humidity, when the toner is stored for a long period of time, it often undergoes deterioration due to the instability of the charge control agent used and becomes unusable due to poor charging properties.

Furthermore, when conventional charge control agents are used in toner, long-term use may cause the charge control agents to adhere to the surface of the photoreceptor or promote toner adhesion, adversely affecting latent image formation (
There are many things that have a negative effect on the cleaning process of a copying machine, such as the filming phenomenon), those that cause scratches on the surface of the photoreceptor or cleaning members such as cleaning blades, and those that accelerate wear of the members.

Furthermore, when conventional charge control agents are used in toners, there are many that have a large effect on the thermal melting properties of the toners and reduce the fixability of the toners. In particular, there are some that worsen the high-temperature offset performance, increase the clinging of the transfer paper to the roller during heat roll fixing, and shorten the durable life of the roller.

As described above, conventional charge control agents have many drawbacks.
There is a strong demand in the technical field to improve these.
Although many improved techniques have been proposed so far, the reality is that no one has yet been found that is comprehensively satisfactory for practical use.

[Problems to be Solved by the Invention] An object of the present invention is to provide a new technique for toner charge control that overcomes these problems.

Another object of the present invention is to stabilize the amount of triboelectric charge between toner particles, between a toner and a carrier, or between a toner and a toner carrier such as a sleeve in the case of -component development, and to maintain a stable triboelectricity distribution. To provide a developer that is sharp and uniform, and whose charge amount can be controlled to suit the developing system used.

Still another object is to develop a developer that is faithful to the latent image and to perform the transfer, that is, without toner adhesion in the background area during development, without fogging or toner scattering around the edges of the latent image. High image density can be obtained,
To provide a developer with good halftone reproducibility.

Still another object is to provide a developer that maintains its initial characteristics even when the developer is used continuously over a long period of time, and that causes no toner aggregation or change in charging characteristics.

Another objective is to develop a developer that reproduces stable images that are not affected by changes in temperature and humidity, especially a developer that has high transfer efficiency and does not cause scattering or transfer dropouts during transfer at high or low humidity. It's on offer.

Still another object is to provide a bright chromatic developer.

Still another object is to provide a developer with excellent storage stability that maintains its initial characteristics even during long-term storage.

Still another object is to provide a developer that does not stain, abrade, or scratch the electrostatic latent image surface and is easy to clean.

Still another object is to provide a developer that has good fixing properties, particularly a developer that does not have problems such as high-temperature offset.

[Means and effects for solving the problems] The present invention provides a toner containing bis(diorganotincarboxylate) dicarboxylate. It has been found that the acid salt is thermally and temporally stable, has low hygroscopicity, and is a high-quality charge control agent that provides a developer with excellent electrophotographic properties when included in a developer.

Although it is unclear what causes the positive triboelectrification of bis(diorganotincarboxylate) dicarboxylate, 5
It is thought that the n-0 bond plays an important role. Therefore, the organo group bonded to the tin atom is not particularly limited. However, preferably, it is more effective to use an electron-donating group that increases the charge density of the tin atom.

Examples include alkyl groups such as methyl group, ethyl group, tert-butyl group, octyl group, and stearyl group, cyclic alkyl groups such as cyclopentyl group, cyclohexyl group, and cyclooctyl group, and derivatives having these as basic skeletons. In addition, although the charge density decreases slightly, it is possible to use 7-ralkyl groups such as benzyl group and phenethyl group, or phenyl group, naphthyl group, anthryl group, tolyl group, and 4-tart group.
Heptaryl groups such as -butylphenyl group, p-methoxyphenyl group, and P-dimethylaminophenyl group, or derivatives having these as basic skeletons can also be used favorably.

Further, any carboxylic acid or dicarboxylic acid can be used as long as it is thermally stable and has low hygroscopicity.

Typical specific examples of the bis(diorganotincarboxylate) dicarboxylate of the present invention are shown below. Methods for incorporating the above compound into the developer include a method of adding it inside the developer and a method of adding it externally. There is. When internally added, the amount of these compounds used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner manufacturing method, including the dispersion method, and is not uniquely limited. However, it is preferably 0.00 parts by weight per 100 parts by weight of the binder resin.
It is used in an amount of 1 to 10 parts by weight (more preferably 0.5 to 5 parts by weight).

In addition, when externally added, 0.
01 to 10 parts by weight is desirable.

Furthermore, conventionally known charge control agents can be used in combination with the charge control agent of the present invention.

Colorants used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green 1 Hansa yellow G, rhodamine 8G, lake,
Calco oil blue, chrome yellow, quinacridone,
Any conventionally known dyes and pigments such as benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, and disazo dyes and pigments can be used alone or in combination.

The binder resin used in the present invention includes polystyrene,
Monopolymers of styrene and its substituted products such as polyp-chlorostyrene and polyvinyltoluene: styrene-p-chlorostyrene copolymers, styrene-propylene copolymers,
Styrene-vinyltoluene copolymer, styrene-vinylthiphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-methyl chloromethacrylate 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-indene copolymer, styrene - Styrenic copolymers such as maleic acid copolymers and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, 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, etc. Can be used in combination.

In particular, as binder resins suitable for pressure fixing, the following can be used alone or in combination.

Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, oxidized polyethylene, polytetrafluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (7-mer ratio 5-30:95-70)
, olefin copolymers (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), polyvinylpyrrolidone, methyl vinyl ether-maleic anhydride copolymer, maleic acid Modified phenolic resin, phenol-modified terpene resin.

Further, when the toner of the present invention is used as a two-component developer, it is used in combination with a carrier powder.

All known carriers can be used in the present invention, such as magnetic powders such as iron powder, ferrite powder, and nickel powder, glass beads, etc., and carriers whose surfaces have been treated with resin, etc. Things can be given.

Furthermore, the toner of the present invention can further contain a magnetic material and be used as a magnetic toner. The magnetic materials contained in the magnetic toner of the present invention include iron oxides such as magnetite, hematite, and ferrite, iron, cobalt, and nickel. metals such as or with these metals aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese,
Examples include alloys with metals such as selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These ferromagnetic materials have an average particle size of 0.1 to 2. It is desirable that the amount is approximately 20 to 200 parts by weight per 100 parts by weight of the resin component, and particularly preferably 40 to 150 parts by weight per 100 parts by weight of the resin component.

Further, the toner of the present invention may be mixed with additives as necessary. Examples of additives include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, flow agents such as colloidal silica and aluminum oxide, anti-caking agents, and carbon black and tin oxide. conductivity imparting agents such as
Alternatively, there are fixing aids such as low molecular weight polyethylene.

To prepare the toner for developing an electrostatic image according to the present invention, the charge control agent according to the present invention is mixed with a vinyl or non-vinyl thermoplastic resin, a pigment or dye as a coloring agent, and a magnetic material as necessary. , additives, etc. are thoroughly mixed using a ball mill or other mixer, and then melted, kneaded, and kneaded using a heat kneader such as a heated roll, kneader, or Nixtruder to make the resins mutually compatible. Pigment or dye is dispersed or dissolved in the solution, and after cooling and solidifying, it is crushed and classified to obtain an average particle size of 5.
~20gm of toner can be obtained.

Alternatively, the material can be obtained by dispersing the material in a binder resin solution and then spray-drying it, or by mixing the specified material with the monomers that should constitute the binder resin to form an emulsified suspension and then polymerizing it. A polymerization toner manufacturing method for obtaining a toner, a so-called microcapsule toner consisting of a core material and a shell material, and a method in which the toner is contained in the core material, the shell material, or both can be applied.

The toners prepared by these methods can be used for developing to visualize electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. by conventionally known means. This produces a positive effect.

That is, the amount of frictional charge between toner particles is uniform, and the amount of charge can be easily controlled. Furthermore, the toner is extremely stable, with no variation or decrease in the amount of triboelectric charge due to deterioration during use. Therefore, the above-mentioned problems such as development fog, toner scattering, and contamination of electrophotographic photosensitive materials and copying machines can be eliminated, and since the toner of the present invention is extremely superior, It is a toner that can withstand long-term storage without causing phenomena such as agglomeration, clumping, and low-temperature flow, and also has excellent abrasion resistance, fixing properties, and adhesive properties of toner images.

These excellent effects of the toner are further magnified when used in a repetitive transfer copying system in which the operations of charging, exposure, development, and transfer are successively repeated. Furthermore, there is no color tone disturbance caused by charge control agents, and when used as a color electrophotographic toner, it is possible to form color images with excellent colors. However, this does not limit the present invention in any way, and all parts in the following formulations are by weight.

Example 1 Carbon black (Mitsubishi 144) 5 parts Low molecular weight polyethylene wax 2 parts Compound (1) 2
After thoroughly mixing the above materials in a blender, they were kneaded with two rolls heated to 150°C. After the kneaded material was left to cool naturally, it was roughly pulverized using a cutter mill, then pulverized using a pulverizer using a jet stream, and further classified using an air classifier to obtain a fine powder with a particle size of 5 to 20 μm. Ta.

A developer was prepared by mixing 5 parts of the fine powder with 100 parts of iron powder carrier having an average particle size of 50 to 80 cm.

Next, by a conventionally known electrophotographic method,
A negative electrostatic image was formed, and this was powder-developed using the above-mentioned developer using a magnetic brush method to create a toner image, which was transferred to plain paper and heat-fixed. The resulting transferred image had a sufficiently high density, no fogging, and no toner scattering around the image, resulting in a good image with high resolution.

Further, during durability, the above-mentioned filming phenomenon related to toner on the photoreceptor was not observed at all, and no problems were found in the cleaning process. Also, there were no troubles in the fixing process at this time, and at the end of the 30,000-sheet durability test, the fixing machine was observed and there were no scratches or damage to the rollers, and there was almost no dirt from offset toner, so there were no practical problems at all. Ta.

In addition, when the environmental conditions were set to 35°C and 85%, the image density was almost the same as normal temperature and humidity, and clear images were obtained without fogging or scattering, and the durability was 30,000 yen.
There was almost no change up to 0 sheets.

Next, when a transferred image was obtained at a low temperature and low humidity of 15° C. and 10%, the image density was sufficiently high, the solid ring was developed and transferred extremely smoothly, and the image was excellent without any scattering or hollow spots.

Comparative Example 1 A developer was obtained in the same manner as in Example 1, except that 2 parts of nigrosine dye (Nigrosine Base EX manufactured by Orient Chemical Industry Co., Ltd.) was used instead of 2 parts of compound (1), and development, transfer, and fixing were carried out in the same manner. I got the image.

At room temperature and humidity, there was little fog, but the image density was low at 1.06, line drawings were scattered, and solid rings were noticeably rough.

Further, during durability, the toner material formed a film in the form of thin stripes on the surface of the photoreceptor after about 10,000 sheets, and began to appear as lines on the image. This is so-called filming, and is thought to be due to the charge control agent changing the lubricity of the toner powder.

Furthermore, during durability, the fixed image tended to be easily caught in the fixing roller during the fixing process, and there was difficulty in releasability from the roller.

When an image was obtained at 35° C. and 85%, the image density was as low as 0.88, and fogging, scattering, and roughness increased. Transfer efficiency was also low. When an image was obtained under conditions of 15° C. and 10%, the image density was as low as 0.91, and there was severe scattering, fogging, roughness, and noticeable transfer omissions.

Example 2 A developer was obtained in the same manner as in Example 1 except that 3 parts of compound (2) was used instead of 2 parts of compound (1), and the development, transfer, and
Fixation was performed and an image was obtained in the same manner.

The detailed results are shown in Tables 1 and 2, and satisfactory results almost the same as in Example 1 were obtained.

Example 3 A developer was obtained in the same manner as in Example 1 except that 2 parts of compound (3) was used instead of 2 parts of compound (1), and development, transfer, and
Fixation was performed and an image was obtained in the same manner.

The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 1 were obtained.

Example 4 A developer was obtained in the same manner as in Example 1 except that 2 parts of compound (4) was used instead of 2 parts of compound (1), and development, transfer, and
Fixation was performed and an image was obtained in the same manner.

The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 1 were obtained.

Example 5 Triiron tetroxide EPT-500 (manufactured by Toda Kogyo) 60 parts Low molecular weight polypropylene wax 2 parts Compound (
1) 2 parts The above materials were thoroughly mixed in a blender and then kneaded with two rolls heated to 150°C. After the kneaded material is left to cool naturally, it is roughly pulverized using a cutter mill, then pulverized using a pulverizer using a jet stream, and further classified using an air classifier to obtain a fine powder with a particle size of 5 to 20 m. I got it.

Next, 0.4 parts of silica was mixed with 100 parts of the fine powder using a sample mill to prepare a -component magnetic toner.

When this toner was applied to a reprint copying machine (trade name NP-1502, manufactured by Canon ■) and an image was produced, good results similar to those of Example 1 were obtained.

Example 6 A developer was obtained in the same manner as in Example 5, except that 3 parts of compound (2) was used instead of 2 parts of compound (1), and development, transfer, and fixing were carried out in the same manner. I got it.

The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 5 were obtained.

Example 7 A developer was obtained in the same manner as in Example 5, except that 2 parts of compound (3) was used instead of 2 parts of compound (1), and development, transfer, and fixing were carried out in the same manner as in Example 5. I got it.

The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 5 were obtained.

Comparative Example 2 A developer was obtained in the same manner as in Example 5, except that 2 parts of benzyl-methyl-hexadecyl ammonium chloride was used instead of 2 parts of compound (1) in Example 5,
Images were obtained similarly. At room temperature and humidity, there was little fog, but the image density was low at 0.81, line drawings were scattered, and solid black was noticeably rough.

In addition, the above-mentioned filming phenomenon during durability and problems in the fixing process were almost the same as those in Comparative Example 1. Also, when images were obtained under conditions of 35° C. and 85%, the image density was 0. 72, and fogging, scattering, and roughness increased, making it unusable.

Transfer efficiency was also low. When an image was obtained under the conditions of 15°C and 110%, the image density was as low as 0.73, and there was some scattering.
There was severe fogging and roughness, and transfer omissions were noticeable.

Example 8 Copper phthalocyanine blue pigment 5 parts Low molecular weight polypropylene wax 2 parts Compound (1) 2 parts The above materials were thoroughly mixed in a blender and then kneaded with two rolls heated to 150"C. The kneaded product was left to cool naturally. After coarsely pulverizing with a cutter mill, pulverizing with a pulverizer using a jet stream, and further classifying with an air classifier to obtain a fine powder with a particle size of 5 to 20 gm.

Next, 50 parts of carrier iron powder having a particle size of 50 to 80 gm was mixed with 100 parts of the fine powder to prepare a developer.

When this developer was used to develop an image using the developing method shown in Figure 1, a good image with a bright blue color was obtained. However, no change in image density was observed.

To explain this developing method, in FIG. 1, l is an electrostatic image holder, 2 is a toner carrier, 3 is a hopper, and 52
5 is a magnetic brush made of a carrier toner mixture, 58 is a toner thickness regulating blade, 50 is a fixed magnet, 6 is a developing bias, and 5 is a toner.

That is, the magnetic brush 52 formed on the toner carrier 2 is circulated by rotating the toner carrier 2, and the toner in the hopper 3 is taken in and coated in a thin layer uniformly on the hopper 2.Then, the toner is carried. The body 2 and the electrostatic image holding body 1 are opposed to each other with a gap larger than the thickness of one layer of toner, and the toner 5 on 2 is developed by flying onto the electrostatic charge image on 1.

- The thickness of the toner layer is controlled by the size of the magnetic brush 52, ie, the amount of carrier, and the regulating blade 58. The gap between l and 2 may be made larger than the thickness of the toner layer, and a developing bias of 6 may be applied.

Example 9 Copper phthalocyanine blue pigment 5 parts Low molecular weight polypropylene wax 2 parts Compound (1) 3 parts The above materials were thoroughly mixed in a blender and then kneaded with two rolls heated to 150"C. The kneaded product was left to cool naturally. After coarsely pulverizing with a cutter mill, pulverizing with a pulverizer using a jet stream, and further classifying with a wind classifier,
A fine powder with a particle size of 5 to 20 gm was obtained.

Next, 50 g of magnetic particles with a particle size of 50 to 80 μm are mixed with 5 g of the fine powder, and 10 g of the fine powder is added on top of the magnetic particles.
0 g was added to form a developer.

Using this developer, magnetic particles were made to exist on the sleeve of the developing section so that the amount of the magnetic particles on the sleeve was about 50 mg/c+s2, and a frequency of 80H was applied to the sleeve.
z, a voltage with a peak-to-peak value of 1.4 kV and a center value of 1,300 cm was applied for development.

A good image with a bright blue color was obtained, and the image quality was 1.500.
Almost no change in image density was observed even after obtaining a single image.

The evaluation results of each example and comparative example are shown in Tables 1 and 2.

Table 1 0: Good, Δ: Slightly poor, ×: Bad Table 2 0: Good, OΔ: Slightly good, Δ: Slightly poor, X: Poor C
1 Effects of the Invention The following effects can be obtained by the present invention.

(1) The amount of frictional charge between toner particles, between toner and carrier, between toner and toner carrier such as a sleeve in the case of -component development is stable, and the distribution of frictional charge is sharp and uniform. It is a developer that can control the amount of charge to suit the developing system used.

(2) The developer is capable of faithfully developing and transferring a latent image, maintains its initial characteristics even when used continuously over a long period of time, and has no change in toner aggregation or charging characteristics.

(3) A developer that can reproduce stable images that are not affected by changes in temperature and humidity, and that can also produce images in vivid chromatic colors.

(4) It is a developer that does not stain, abrade or scratch the electrostatic latent image surface, has an easy cleaning process, has good fixing properties, and is particularly free from problems such as high-temperature offset.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of a developing device to which the positively chargeable toner according to the present invention can be applied. l... Electrostatic image holder, 2... Toner carrier, 5...
・Toner, 50...Magnet, 52...Magnetic brush, 5
8...Regulation blade.

Claims (1)

[Claims] (1) A toner for developing electrostatic images characterized by containing a bis(diorganotincarboxylate) dicarboxylate.