JPS62287262A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a developer which permits the control to the quantity of the electric charge suitable for the developing system to be used by incorporating a diorganotin bisimidazole into the titled toner. CONSTITUTION:The diorganotin bisimidazole has lower hygroscopcity and is a good-quality charge controlling agent to yield the developer having excellent electrophotographic characteristics when incorporated into the developer; therefore, the charge control of the toner is executed by incorporating the diorganotin bisimidazole into the toner. Since an Sn-N bond is considered to make an important contribution to positive frictional chargeability, an organo group which does not considerably decrease the charge density of tin atoms is preferable; for example, cyclic alkyl groups such as methyl group and ethyl group or the derivatives consisting thereof as the basic skeleton are preferable. The diorganotin bisimidazole is synthesized by the dehydrochlorination reaction of a diorganotin dichloride and imidazole.

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 photoconductive insulator layer is provided with a uniform electrostatic charge and a light image is applied to the insulator layer to form an electrostatic latent image, which is then referred to in the art as a toner. Developed and visualized with fine powder,
After transferring the powder image to paper etc. as necessary, heat, pressurize,
Alternatively, fixing is carried out using solvent vapor or the like.

The developing methods applied 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 the cascade method using a carrier, the 7-arpte method using fur, etc.

Examples of -component-based development methods include the powder cloud method, which uses toner particles in a spray state, and the powder cloud method, which uses toner particles in a sprayed state; Contact development method (also referred to as contact development or toner development) in which toner particles are developed by contacting with the latent image surface, the toner particles are charged without directly contacting the latent image surface, and the electric field possessed by the electrostatic latent image is developed. There are a jumping development method in which toner is caused to fly toward the latent image surface, and a gundry method in which development is performed by bringing a magnetic conductive toner into contact with the static image surface.

Conventionally, toners used in these development methods are fine powders in which dyes and pigments are dispersed in natural or synthetic resins. Finely pulverized particles of about 1 to 30 liters 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 hold 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 to be negatively charged, while metal complex salts of heptanoazo dyes, Co 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 as charge control agents are
Its structure is complex, its properties are inconsistent, and its stability is poor. It is also prone to decomposition or deterioration due to decomposition during thermal kneading, mechanical impact, friction, changes in temperature and humidity conditions, etc., and charge controllability is reduced. This phenomenon 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 a thermoplastic resin, a fatal drawback arises in that the amount of friction zone Ti between the toner particles obtained by pulverization varies. have. 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 unreacted fatty acids or salt dispersion products often remain on the toner surface. When exposed, it contaminates the carrier or toner carrier, causing a decrease in toner fluidity, fogging, and a decrease in image density. or,
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. However, the inherent poor dispersion cannot be avoided, and at present, sufficient uniformity of charge 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 charge control agent is exposed on the toner surface. Therefore, when the toner is used under high humidity conditions, it has the disadvantage that a good quality image cannot be obtained because these charge control agents are wood-philic.

In this way, when conventional charge control agents are used in horse chestnuts,
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, making many toners unusable. The instability of the charge control agent causes deterioration, and the charge control agent often 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 toner, there are many that greatly affect the thermal melting properties of the toner and reduce fixing performance.In particular, they worsen high-temperature offset performance, ) There are some that increase the clinging of the transfer paper to the roller and reduce the durability 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 eliminate friction zones between toner particles, or between toner and carrier, or between a torch and a toner carrier such as a sleeve in the case of component development. l! The amount is stable,
Another object of the present invention is to provide a developer which has a sharp and uniform triboelectric charge distribution and can be controlled to a charge amount suitable for 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,
The purpose of the present invention is to provide a developer with good half-tone 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.

Zara's other purpose 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 splatters or transfer omissions during transfer at high or low humidity. It is provided by.

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 action for solving problem U] The present inventors have discovered that diorganotinbisimidazole has low hygroscopicity and
The present invention has been achieved by discovering that it is a high-quality charge control agent that, when contained in a developer, provides a developer with excellent electrophotographic properties.

That is, according to the present invention, a l-ner for developing electrostatic images containing diorganotin bisimidazole is provided.

Although the details regarding the excellent positive triboelectric charging properties of the diorganotin bisimidazole of the present invention are not clear, it is thought that the 5n-N bond plays an important role. Therefore, there are no restrictions on the organo group bonded to the tin atom, but
An organo group that does not significantly reduce the charge density of the tin atom is preferred. Examples of such organo groups include alkyl groups such as methyl group, ethyl group, tert-butyl group, octyl group, and stearyl group, and cyclic alkyl groups such as cyclopentyl group, cyclopentyl group, and cyclooctyl group. A group or a derivative having these as a basic skeleton is preferable.

In addition, although the charge density decreases slightly, aralkyl groups such as benzyl group and phenethyl group, phenyl group, naphthyl group, anthryl group, tolyl &, 4-tert-butylphenyl group, p-methoxyphenyl group, p- Aryl groups such as dimethylamino 2-enyl group or derivatives having these as the basic skeleton can also be used favorably.

Examples of diorgano tin bisimidazoles include the following.

'8 Compound (7) The diocastin bisimidazole of the present invention can be synthesized by dehydrochlorination reaction of diorganotin dichloride and imidazole.

For example, the above compound (1) is synthesized as follows.

30g dibutyltin dichloride and 14g imidazole
After refluxing for 3 hours using toluene as a solvent, the solvent was removed to obtain Compound (1) as a white powder.

Methods for incorporating the above-mentioned diokastin bisimidazole into the developer include a method of adding it inside the developer and a method of adding it externally. When internally added, the amount of diorganotin bisimidazole used is determined by the toner manufacturing method, including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method. Although not limited to, preferably 0.1 to IQ parts by weight (more preferably 0.5 to 0.5 parts by weight) per 100 parts by weight of binder resin.
5 parts by weight).

In addition, when externally added, 0.0 parts by weight per 100 parts by weight of resin.
1 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, Hansa Yellow G, rhodamine 8G, lake,
Calco oil blue, chrome yellow, quinacridone,
Any conventionally known dyes and pigments such as benzidine yellow, rose hengal, triallylmethane dyes, monoazo dyes, and diazo 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-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer 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, nutyrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene- Styrenic copolymers such as 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 Mj4 fat, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorine Examples include chemically modified paraffin and paraffin wax, which can be used alone or 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, polyethylene oxide, polytetrafluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer 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), holivinylpyrrolidone, methyl donyl ether-maleic anhydride copolymer Combined, malemono-ugly 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 and iron such as magnetite, hematite, and ferrite.

Metals such as cobalt, nickel or these metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manogan, selenium, titanium, tungsten, batidium alloys and mixtures 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 about 20 to 200 parts by weight per 100 g of the resin component, particularly preferably 100 g of the resin component. The amount is 40 to 150 parts by weight.

The toner of the present invention may also contain additives as required. Examples of additives include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, or colloidal silica, etc. Fluidity imparting agents such as aluminum oxide, anti-caking agents, or conductivity imparting agents such as carbon black and tin oxide,
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 combined with a vinyl or non-vinyl thermoplastic resin, a pigment or dye as a coloring agent, and, if necessary, a magnetic material. 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, niegu, or extruder to make the resins mutually dissolve. Pigment or dye is dispersed or dissolved, cooled and solidified, then crushed and classified to obtain an average particle size of 5 to 2.
A toner of 0ILI11 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, and have the following advantages: It produces a certain 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 are eliminated, and because 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, since there is no color tone disturbance caused by the charge control agent, it is possible to form color images with excellent colors by using it as a toner for color electrophotography. However, this does not limit the present invention in any way. All parts in the following formulations are parts by weight.

Example 1 Carbon black (Mitsubishi 144) 5 parts Low molecular weight poly, ethylene wax 2 parts Compound (1
) 2 parts The above materials were thoroughly mixed in a blender and then kneaded with two rolls heated to 130°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 lm. I got it.

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

Next, by a conventionally known electrophotographic method,
A negative electrostatic charge 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 flying 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 fuser was observed and found that there were no scratches or damage to the rollers, and there was almost no staining due to offset toner, so there were no practical problems at all. Ta.

Further, when the environmental conditions were set to 35° C. and 85%, the image density was almost unchanged from normal temperature and humidity, and a clear image was obtained without fogging or scattering.

Next, when a transferred image was obtained at 15° C. and 10% low temperature and humidity, the image density was sufficiently high, solid black was developed and transferred extremely smoothly, and the image was excellent with no 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 black was noticeably rough.

Also, during durability, after about 10,000 copies, toner material formed a streak-like film on the surface of the photoreceptor 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 get caught up in the fixing roller during the fixing process, and there was difficulty in peeling it off 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, and roughness, and transfer omissions were noticeable.

Example? 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 steps of 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
After thoroughly mixing the above materials using a blender, they were kneaded using two rolls heated to 130°C. After the kneaded material was left to cool naturally, it was roughly pulverized with a cutter mill, then pulverized with 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 pm. Ta.

Next, 0.4 parts of silica treated with amino group-modified silicone oil was mixed with 100 parts of the fine powder in a sample mill to prepare a -component magnetic toner.

This toner is commercially available copy #jj, (product name NP-150
2 (manufactured by Canon Co., Ltd.) to produce an image, good results almost the same as in 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 In place of 2 parts of compound (1) in Example 5.

A developer was obtained in the same manner as in Example 5, except that 2 parts of benzylmethyl-hexadecyl ammonium chloride was used, and an image was obtained in the same manner. 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.

Furthermore, the above-mentioned filming phenomenon during durability and problems in the fixing process were almost the same as those in Comparative Example 1, and were undesirable.

Further, when an image was obtained under the conditions of 35°C and 185%, the image density was as low as 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 severe scattering, 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 130°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 particles. I got it.

Next, 50 parts of carrier iron powder having a particle size of 50 to 80 μm 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, and after 1500 images, the toner/carrier amount was 10g to 150g. 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 using a carrier toner mixture, 5 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, takes in the toner in the hopper 3, and uniformly coats the toner 2 in a thin layer. Next, the toner carrier 2 and the electrostatic image carrier 1 are opposed to each other with a gap larger than the thickness of one toner layer, and the toner 5 on the toner 2 is caused to fly onto the electrostatic charge image on the 1 for development.

The thickness of the toner layer is controlled by the size of the magnetic brush 52, i.e. the amount of carrier, and the regulating blade 58. ■ and 2
A developing bias of 6 may be applied by making the gap between the toner and the toner layer larger than the thickness of the toner layer.

Example 9 Copper phthalocyanine blue pigment 5 parts Low molecular weight polypropylene wax 2 parts Compound (1)
7.5 parts of the above materials were thoroughly mixed in a blender and then kneaded with a two-wood roll heated to 130°C. After the kneaded material was left to cool naturally, it was coarsely ground in a Kasita mill.
The mixture was pulverized using a pulverizer using a jet stream, and further classified using an air classifier to obtain a fine powder having a particle size of 5 to 20 liters.

Next, 50 g of magnetic particles with a particle size of 50 to 80 J are mixed with 5 g of the fine powder, and 10 g of the fine powder is added on top of the mixture.
0g 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 50a+g/ca+2, and a frequency of 800 was applied to the sleeve.
Hz, a voltage with a peak-to-peak value of 1.4 kV and a center value of -300 V was applied for development.

A good image with a bright blue color was obtained.

Even after obtaining 1.500 images, almost no change was observed in the image density.

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

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

(1) Between toner particles or between toner and carrier.

- In the case of component development, the amount of triboelectric charge between the toner and a toner carrier such as a sleeve is stable, and the distribution of triboelectricity is sharp and uniform, and the amount of charge can be controlled to suit the developing system used. It is a developer.

(2) It is a developer that is capable of faithfully developing and transferring an image, maintains its initial characteristics even after continuous use 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 unaffected 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. 1... Electrostatic image holder, 2... Toner carrier, 5...
・Toner, 50...Magnet, 52...Magnetic brush, 5
Day... Regulation blade.

Claims (1)

[Claims] (1) A toner for developing electrostatic images characterized by containing diorganotinbisimidazole.