JPS61217064A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To stabilize triboelectrification amt., to render its distribution sharp and uniform, to optimize a development system, and to obtain a sharp image without being affected by temp. and humidity by incorporating a specified quaternary phosphonium salt as an electrostatic charge controller. CONSTITUTION:A toner contains a quaternary phosphonium salt stable against heat and time lapse, small in hygroscopicity and superior in charge control performance, and represented by the formula shown on the right in which R1-R4 are each H, alkyl, cycloalkyl, aryl, or aralkyl and A<-> is BF<->4 or BF<->6. The use of such a charge controller triboelectrification amt. between toner particles themselves, between toner particles and carrier particles, and between those and a toner carrying body to be stabilized, its distribution to be made sharp and uniform, and this amt. to be adapted to a development system, accordingly, development and transfer to be enhanced in fidelity to a latent image, fixability to be improved, and trouble in a cleaning step, such as staining and damaging of the latent image, to be prevented, agglomeration of the toner to be prevented, and a sharp chromatic color image to be obtained.

Description

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.

[Conventional technology]

Conventionally, as an electrophotographic method, U.S. Patent No. 2,297°89
1, Special Publication No. 42-23910, and Special Publication No. 43
Various methods are described in Japanese Patent Application No. 24748, etc., but these methods basically apply a uniform electrostatic charge onto a photoconductive insulating layer and irradiate the insulating layer with a light image to generate static electricity. An electrostatic latent image is formed, and then this latent image is developed and visualized using a fine powder called toner using the relevant technology. After transferring the powder image to paper or the like as necessary, it is fixed by heating, pressure, or solvent vapor. This is what we do.

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 a magnetic brush method using an iron powder carrier, a cascade method using a bead carrier, a fur brush method using fur, etc., depending on the type of carrier for conveying the toner.

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 referred to as toner development), jumping development method in which toner particles are not brought into direct contact with the electrostatic latent image surface, but are charged and flown toward the latent image surface by the electric field of the electrostatic latent image; and magnetic conductive method. There is the MagneDry method, which develops by bringing a toner into contact with the electrostatic latent 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 particles 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 the following:

[1] The following substances are used to control the toner to be positively charged.

Nigrosine, azine dyes containing an alkyl group having 2 to 1B carbon atoms (Japanese Patent Publication No. 1827/1983), basic dyes (e.g. C, E, Ba5ic Yellow 2 (C,
1,41000), C, 1, Ba5ic Yellow
3, C,1,Ba5ic Red 1 (C,1
゜45180), C,1,Ba5ic Red 9 (
C,1,42500), C,I.

Ba5ic Violet l (C, 1, 42535
), C,1,Ba5icViolet 3 (
C,1,42555), C,l Ba5ic Vi
oletlG (C, 1, 45170), C, 1, Ba5
ic Violet 14 (C, 1°42510
), C,1,Ba5ic Blue 1 (C,1
, 42025), G, I.

Ba5ic Blue 3 (C, l 51005),
C, I-Ba5ic Blue5 (C, 1,421
40), C,1,Ba5ic Blue 7 (C,1
゜425115), C,1,Ba5ic Blue
9 (C, 1, 52015), c, r.

Ba5ic Blue 24 (C, 1, 5203
0), C,1,Ba5ic Blue25 (
C,1,52025), C,1,Ba5ic
Blue 28 (C, 1°44045), C,! ,
Ba5ic Green 1 (C, 1,420
40).

C,1,Ba5ic Green 4 (C,1,42
000), etc.), lake pigments of these basic dyes (lake-forming agents include phosphotungstic acid and phosphomolybdic acid.

Phosphorous tungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), C,1,5olvent Black 3
(C.

1, 28150), HA7guizo -G (C,
1,11680), C01, Mordant Bla
ck 11, C, 1, Pigment Black 1
, Gilt Night, Asphalt, etc.

Quaternary ammonium salt 1 For example, benzylmethyl-hexadecyl ammonium chloride, decyl-trimethylammonium chloride, organic tin compounds such as dibutyltin oxide, metal salts of higher fatty acids, inorganic fine powders such as glass, mica, zinc oxide, etc., EDTA, Polyamine resins such as metal complexes of acetylacetone, vinyl polymers containing amine groups, and condensation polymers containing amine 7 groups.

(2) The following substances can be used to control the negative chargeability of toner.

Metal complex salts of monoazo dyes described in Japanese Patent Publications Nos. 41-20153, 43-27598, 44-8397, and 45-28478.

Dyes and pigments such as nitrofumic acid and its salts or C,1,141345 described in JP-A-50-133338, JP-B No. 55-42752, JP-B-Sho 5B-415
No. 08, Special Publication No. 59-7384, Special Publication No. 511-73
Salicylic acid, naphthoic acid, etc. described in No. 85, etc.
C01Cr of guicarboxylic acid, metal complexes such as Fe, sulfonated copper phthalocyanine pigments, nitro groups, styrene oligomers with halogens introduced, chlorinated paraffins,
Melamine resin etc.

Many of these charge control agents are derived from dyes and pigments.
Generally, they have a complex structure, and many of them have strong coloring properties.

Recently, there are some newly proposed products that are different from these, but none have superior overall performance to dyes and pigments, and examples of dyes and pigments still being used are still unsatisfactory. Most of them are.

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 also decompose during thermal kneading (1) due to mechanical shock, friction, changes in temperature and humidity conditions, etc. Otherwise, it is likely to change in quality and cause a phenomenon in which charge controllability is deteriorated.

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 in the past to achieve more uniform dispersion. Although it is used.

Dispersion products of unreacted fatty acids or salts are often exposed on the toner surface and contaminate the carrier or toner carrier, causing a decrease in toner fluidity, fog, and a decrease in image density. There is. 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. However, the inherent poor dispersion cannot be avoided, and at present, sufficient uniformity of charge has not yet been obtained for practical use.

Further, most of the substances generally known as charge control agents have a dark color and cannot be incorporated into a bright chromatic developer.

In addition, many of the charge II types are hydrophilic, and due to poor dispersion in the resin, dyes are exposed on the toner surface when crushed after melting and mixing, and these charge control problems occur under high humidity conditions. Since the agent is wood-philic, it has the disadvantage that good quality images cannot be obtained.

In this way, when conventional charge control agents are used in toner,
Between toner particles, between toner and carrier, between toner and toner carrier such as a sleeve,
This causes variations in the amount of charge generated on the surface of toner particles, which tends to cause problems such as development fog, toner scattering, and carrier contamination, and these problems become noticeable when copying is repeated a large number of times. The result is practically unsuitable for copying machines.

Furthermore, under high humidity conditions, the transfer efficiency of toner images decreases significantly, making many toners unusable. Due to the instability of the charge control agent, it often undergoes deterioration 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 greatly affect the thermal melting properties of the toner and reduce fixing performance.In particular, they worsen offset resistance at high temperatures, and heat roll fixation There are some cases where the transfer material increases the clinging property of the roller to the roller and reduces 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.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a new technique for toner charge control that overcomes these drawbacks.

The object of the present invention is to stabilize the amount of triboelectric charge between toner particles, between toner and carrier, or between toner and a toner carrier such as a sleeve in the case of -component development, and to have a sharp triboelectricity distribution. The purpose of the present invention is to provide a developer which is 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. 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 for solving problems]

The present invention provides an electrophotographic toner for developing an electrostatic image, which contains a linear cyclic alkyl group, an aralkyl group, an aryl group, or a quaternary phosphonium salt represented by the following general formula [1]. The present inventors have discovered that the quaternary phosphonium salt represented by the above general formula CI) is thermally and temporally stable; 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.

Typical specific examples of the quaternary phosphonium salt represented by the general formula [1] include the following.

[Compound example]

14″ These compounds are synthesized by known methods.

That is, the corresponding quaternary phosphonium chloride may be treated with an aqueous solution of fluoroboric acid or an aqueous solution of hexafluorophosphoric acid.

For example, compound [1] is synthesized as follows: Tetra-tolylphosphonium chloride is obtained by reacting p-chlorotoluene with p-chlorotoluene. When treated with an aqueous solution of fluoroboric acid, Compound Example [1] is obtained.

Generally, the compound has an average particle size of 10 to 0.01 g.

In particular, it is preferable to use the particle size in the range of 5 to 0.1 μl for toner adjustment.

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. 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 uniquely limited. However, it is preferably 0.1 to 20 parts by weight (more preferably 0.1 to 20 parts by weight) per 100 parts by weight of the binder resin.
It is used in a range of 5 to 10 parts.

Also, if externally added, it should be added to 100 parts by weight of resin.

0.01 to 10 parts by weight are preferred.

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

Coloring agents used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Handi Yellow G, rhodamine 6G lake, calco oil blue, chrome yellow, and quinacridone. Any conventionally known dyes and pigments such as , benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, 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-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer Coalescence, 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 ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resins ,
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 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), 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.

As carriers that can be used in the present invention, all known carriers can be used. For example, magnetic powders such as iron powder, ferrite powder, nickel powder, glass beads, etc., and carriers whose surfaces are treated with resin etc. Things can be given.

Furthermore, the toner of the present invention can 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 aluminum, cobalt, copper,
Examples include alloys with metals such as lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These ferromagnetic materials preferably have an average particle size of about 0.1 to 2 JL, and the amount to be included in the toner is about 20 to 200 parts by weight per 100 parts by weight of the resin component, particularly preferably 100 parts by weight of the resin component. 40 to 150 parts by weight.

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,
Alternatively, conductivity imparting agents such as carbon black and tin oxide, fixing aids such as low molecular weight polyethylene, etc. may also be used.

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, 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, niegu, or extruder to make the resins mutually dissolve. A toner having an average particle size of 5 to 20 JL can be obtained by dispersing or dissolving the pigment or dye, cooling and solidifying, and then crushing and classifying.

Alternatively, after dispersing the material in a binder resin solution.

Methods such as a method for obtaining toner by spray drying, or a polymerization method for producing a toner by mixing a specified material with the monomer that constitutes the binder resin to form an emulsified suspension and then polymerizing the toner are applied. can.

Toners produced by these methods can be used for developing to visualize electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. by any conventionally known means, and can be used as follows: It has excellent effects.

That is, the amount of frictional charge between toner particles is uniform, and the amount of charge can be easily controlled. In addition, the toner is extremely stable, with no variation or decrease in the amount of triboelectric charge due to deterioration during use. Therefore, if the above-mentioned problems such as development fog, toner scattering, and contamination of electrophotographic photosensitive materials and copying machines are eliminated, problems such as toner aggregation, agglomeration, and low-temperature flow during storage, which were major drawbacks in the past, can be avoided. This is a toner that can withstand long-term storage without causing any problems, and also has excellent abrasion resistance, fixing properties, and adhesive properties of toner images.

The excellent effect of such toner is charging and exposure.

When used in a repetitive transfer type copying system in which development and transfer operations are continuously repeated, the effect is further enhanced. Furthermore, since there is little color disturbance caused by the charge control agent, it is possible to form color images with excellent colors when used as a color electrophotographic toner.

〔Example〕

The present invention will be specifically explained below with reference to Examples, but this is not intended to limit the present invention in any way. All parts in the following formulations are by weight.

Example 1 Styrene/butyl acrylate (8G/20) copolymer 100 parts (weight average molecular weight Mw: approximately 300,000) Carbon black (Mitsubishi #44) 10 parts Unbalanced molecular weight polyethylene wax 2 parts Compound [1]
] 2 parts The above materials were thoroughly mixed in a blender and then kneaded with a two-wood roll heated to 150°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. Obtained.

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 IL.

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, no toner scattering around one image, and a good image with high resolution was obtained. Transfer images were created continuously using the above developer to examine durability.
The transferred image after 30,000 sheets is also compared with the initial image,
It was a completely unremarkable image.

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 disassembled and observed, but there were no scratches or damage to the rollers, and there was almost no dirt from offset toner, so it was practically perfect. There were no problems.

In addition, when the environmental conditions were set to 35°C and 85%, the image density was almost the same as at room temperature and humidity, and clear images with no fogging or scattering were obtained, and the durability remained unchanged up to 30,000 sheets. When a transferred and fixed image was obtained at 15 DEG C. and 10% low humidity, the image density was sufficiently high, solid black was developed and transferred very smoothly, and the image was excellent with no scattering or hollow spots. Durability was carried out under these environmental conditions, and the density fluctuation was ±0.2 up to 30,000 copies, which was sufficient for practical use, even though continuous and repeated copies were made.

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

At room temperature, there is little fog, but the image density is low! , OB and low line drawings were scattered, and the solid black was noticeably rough. #I checked the magnetism, but the density dropped to 0.83 when using 3G and Goo sheets.

Also, during durability, after about 10,000 sheets, toner material formed a thin strip-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 under conditions of 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. I tried to take continuous images, but 3
After about 0,000 sheets, the density became 0.53, making it impractical.

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 an image was obtained in the same manner by performing development, transfer, and fixing.

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 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 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 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 almost the same satisfactory results as in Example 1 were obtained.

Example 5 Styrene/butyl acrylate (80/20) copolymer 100 parts (weight average molecular weight Mw: approximately 300,000) 60 parts triiron tetroxide EPT-500 (manufactured by Toda Kogyo) 2 parts low molecular weight polypropylene wax 2 parts Compound [1] 2
The materials listed above were thoroughly mixed using a blender and then kneaded using 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 l. Obtained.

Next, hydrophobic colloidal silica R was added to 100 parts of the fine powder.
0.4 part of -972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed in a sample mill to prepare a -component magnetic toner.

When this toner was applied to a commercially available copying machine (trade name NP-1502, manufactured by Canon ■) and an image was produced, good results almost 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 (2), and images were formed in the same manner as in Example 5. Obtained.

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 fixation were carried out in the same manner to produce an image. 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 benzylmethyl-hexadecyl ammonium chloride was used instead of 2 parts of compound [1], and an image was obtained in the same manner. At room temperature and humidity, there is little fog, but the image density is 0.8
1 and the line drawings are scattered.

The solid black was noticeably rough. I checked the durability, but it was 30
The density decreased to 0.48 after printing ,000 sheets.

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.

When an image was obtained at 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 images were obtained under conditions of 15° C. and 10%, the density per image was as low as 0.73, and scattering, fogging, and roughness were severe, and transfer omissions were noticeable. Continuous image formation was performed, but the density became 0.59 after 30,000 sheets, making it impractical.

Example 8 Styrene/butyl acrylate (80720) copolymer 100 parts (weight average molecular weight Mw: approximately 300,000) Copper phthalocyanine blue pigment 5 parts Low molecular weight polypropylene work 2 parts Compound [1] 2
The materials listed above were thoroughly mixed using a blender and then kneaded using 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 air flow, and further classified using an air classifier to obtain a fine powder with a particle size of 5 to 20 g. I got it.

Next, 50 g of magnetic particles having a particle size of 50 to 80 l were mixed with 100 parts of the fine powder to prepare a developer.

When images were developed using this developer using the development method described below, good images with a bright blue color were obtained, and after producing 1500 images, the toner/carrier was 10
Even when the weight was 150 g, there was almost no change in image density, and after that, images were printed on up to 30,000 sheets while replenishing toner, and good images were obtained.

This developing method will be explained using FIG. 1.

The carrier-toner mixture formed on the toner carrier 2 is circulated by the magnetic brush 52 by rotating the toner carrier 2, and the toner in the hopper 3 is taken in and uniformly coated in a thin layer on the carrier 2). Let it coat. Next, the toner carrier 2 and the electrostatic image carrier 1 are made to face each other with a gap greater than the thickness of the toner layer, and the toner 5 on the carrier 2 is transferred to the electrostatic image carrier l.
The image is developed by flying onto the electrostatic charge image above.

The thickness of the toner layer is controlled by the size of the magnetic brush 52, the amount of magnetic particles, and the regulating blade. The gap between the electrostatic image carrier 1 and the toner carrier 2 may be made larger than the thickness of the toner, and the developing bias 6 may be applied.

The evaluation results of each example and comparative example are shown in Tables 1 and 2. In the table, O indicates good, OΔ indicates slightly good, Δ indicates slightly poor, and × indicates poor.

〔Effect of the invention〕

The effects obtained by the present invention are as follows.

By using the toner for developing an electrostatic image of the present invention, [1] 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 is stabilized. .

In addition, the triboelectric charge distribution becomes sharp and uniform, and the charge amount can be controlled to suit the developing system used.

(2) It is possible to develop and transfer a latent image faithfully, and even when used continuously for a long period of time, it maintains its initial characteristics and does not cause toner aggregation or change in charging characteristics.

(3) Stable images that are unaffected by changes in temperature and humidity can be reproduced, and images in vivid chromatic colors can be obtained.

(4) The cleaning process is facilitated without staining, abrading, or scratching the electrostatic latent image surface, and the fixing properties are excellent, and there are no problems even with high-temperature offset, which is particularly likely to cause trouble.

[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, holding body, 2... Toner carrying body, 3
...Hopper 5...Toner. 6...Bias, 50...Magnet, 52...
Magnetic brush, 58...Regulation blade.

Claims (1)

[Scope of Claims] An electrophotographic toner for developing electrostatic images, characterized by containing a quaternary phosphonium salt represented by the following general formula [1]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [1] (In the formula, R_1, R_2, R_3, R_4 represent hydrogen, an alkyl group, a cyclic alkyl group, an aralkyl group, an aryl group, or any of these substituents, A^- is BF_4
Indicates ^- or PF_6^-. )