JPH0638168B2 - Positively charged toner for electrostatic image development - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel positively charged toner for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like.

[Prior Art] Conventionally, various methods for electrophotography have been described in US Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910, Japanese Patent Publication No. 43-24748, etc., but they are not essential. Forming a static latent image by applying a uniform electrostatic charge on the photoconductive insulator layer and irradiating the insulator layer with a light image,
Subsequently, the latent image is developed and visualized by fine powder called toner in the art, and if necessary, the powder image is transferred to paper or the like, and then fixed by heating, pressurizing, or solvent vapor.

As a developing method applied to these electrophotographic methods,
It is roughly classified into a dry development method and a wet development method. The former is further divided into a method of using a two-component developer and a method of using a one-component developer. Depending on the type of carrier that carries the toner, the two-component developing method
Magnet brush method using iron powder carrier, beads
There are a cascade method using a carrier and a fur brush method using a fur.

Further, those belonging to the one-component developing method include a powder cloud method in which toner particles are sprayed and a contact developing method (contact developing or (Also referred to as toner development), a jumping development method in which toner particles are not brought into direct contact with an electrostatic latent image but are charged and electrostatically charged to fly toward the latent image surface by an electric field having an electrostatic latent image. , A magnetic dry method of developing by bringing a magnetic conductive toner into contact with an electrostatic latent image.

As a toner applied to these developing methods, a fine powder in which a dye or a pigment is dispersed in a natural or synthetic resin is conventionally used. For example, particles in which a colorant is dispersed in a binder resin such as polystyrene and finely pulverized to about 1 to 30 μm are used as a toner. A magnetic toner containing magnetic particles such as magnetite is used. In the case of a system using a so-called two-component developer, the toner is usually mixed with carrier particles such as glass beads and iron powder before use.

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

To retain the electric charge of the toner, it is possible to utilize the triboelectric chargeability of the resin, which is a component of the toner, but in this method the toner chargeability is small, so the image obtained by development is easily fogged and is not clear. It will be Therefore, in order to impart a desired triboelectric chargeability to the toner, a dye, a pigment or a charge control agent which imparts the chargeability is added.

The charge control agents currently known in the art include the following.

(1) The following substances control the toner to be positively charged.

Nigrosine, azine dyes containing alkyl groups having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), basic dyes (eg CI
Basic Yellow 2 (CI 41000), CI Basic Yellow 3
, CI Basic Red 1 (CI 45160), CI Basic Red
9 (CI42500), CI Basic Violet 1 (CI 42535),
CI Basic Violet 3 (CI 42555), CIBasic Viole
t 10 (CI 45170), CI Basic Violet 14 (CI 4251
0), CI Basic Blue 1 (CI 42025), CI Basic Blu
e 3 (CI51005), CIBsic Blue 5 (CI 42140), C.
I. Basic Blue 7 (CI 42595), CI Basic Blue 9
(CI 52015), CIBasic Blue 24 (CI52030), CI
Basic Blue 25 (CI 52025), CI Basic Blue 26
(CI44045), CI Basic Green 1 (CI 42040), C.
I. Basic Green 4 (CI 42000), CI42510, CI 451
70 etc.). Lake pigments of these basic dyes (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), CISolventBlack 3 ( CI26150), Hansa Yellow G (CI11680), CI Mordlant Black 11, C.
I. Pigment Black 1, Gilsonite, Asphalt, etc.

Quaternary ammonium salts such as benzolmethyl-hexadecylammonium chloride, decyl-trimethylammonium chloride, organic tin compounds such as dibutyltin oxide, metal salts of higher fatty acids, glass, mica, inorganic fine powders of zinc oxide, EDTA, acetylacetone Polyamide resins such as amino group-containing vinyl polymers and amino group-containing condensation polymers, such as the metal complexes of 1.

(2) The following substances control the toner to be negatively charged.

Japanese Patent Publication No. 41-20153, 43-27596, 44-6397, 45-
Monoazo dye metal complex salts described in No. 26478 and the like.
Nitrohumic acid and its salts or dyes and pigments such as CI 14645 described in JP-A-50-133338.

And Japanese Patent Publications 55-42752, 58-41508, 59
Metal complexes of salicylic acid, naphthoic acid and dicarboxylic acid such as Co, Cr and Fe described in JP-A-7384 and JP-B-59-7385. Sulfonated copper phthalocyanine pigment. Styrene oligomer with nitro group and halogen introduced. Chlorinated paraffin, melamine resin, etc.

Many of these charge control agents are derived from dyes and pigments,
The structure is generally complicated and has many strong coloring properties.

Among the newly proposed ones, there are some that are different from these, but there is no one that surpassed the dye-pigment system in terms of overall performance, and there are still examples of dyes that are unsatisfactory. Mostly.

These are usually added to a thermoplastic resin, thermally melt-dispersed, finely pulverized, and adjusted to an appropriate particle size as needed before use.

However, these dyes as charge control agents have a complicated structure and inconsistent properties, and are poor in stability. In addition, decomposition or deterioration is likely to occur due to decomposition during thermal kneading, mechanical shock, friction, changes in temperature and humidity conditions, etc., and a phenomenon in which charge controllability is deteriorated is likely to occur.

Therefore, when a toner containing these dyes as a charge control agent is developed using a copying machine, the charge control agent may be decomposed or deteriorated as the number of times of copying increases, and the toner may deteriorate during its durability.

Further, since it is extremely difficult to uniformly disperse these charge control agents in the thermoplastic resin, there is a fatal defect that the triboelectric charge amount between toner particles obtained by pulverization causes a difference. is doing. For this reason, various methods have been conventionally used for more uniform dispersion. For example, a basic nigrosine dye is used by forming a salt with a higher fatty acid in order to improve compatibility with a thermoplastic resin, but unreacted fatty acid or a dispersion product of the salt is often exposed on the toner surface. As a result, the carrier or the toner carrier is contaminated, which causes a decrease in toner fluidity, fog, and a decrease in image density. Alternatively, in order to improve the dispersion of these charge control agents in the resin, a method of mechanically pulverizing and mixing the charge control agent powder and the resin powder in advance and then hot-melt kneading is used. However, the original poor dispersion cannot be avoided, and in the current situation, sufficient charge uniformity for practical use has not yet been obtained.

Further, most of the substances generally known as the charge control agent have a dark color, and thus there is a problem that they cannot be contained in a bright chromatic color developer.

In addition, many charge control agents are hydrophilic, and due to poor dispersion in these resins, when melt-kneaded and then crushed,
The dye is exposed on the toner surface. Therefore, when the toner is used under high humidity conditions, there is a problem that a high quality image cannot be obtained because the charge control agent is hydrophilic.

Thus, when the conventional charge control agent is used in the toner,
Between the toner particles, between the toner and the carrier, or between the toner carrier such as the toner and the sleeve, the amount of electric charge generated on the surface of the toner particles varies, and development fog, toner scattering, carrier contamination, etc. Failures are likely to occur. Further, this obstacle appears as a remarkable phenomenon when the number of times of copying is increased, and is substantially unsuitable for a copying machine.

Further, under high humidity conditions, the transfer efficiency of toner images is significantly reduced, and many of them cannot be used. Even at room temperature and normal humidity, when the toner is stored for a long period of time, it deteriorates due to instability of the charge control agent used and often becomes unusable due to poor chargeability.

In addition, when a conventional charge control agent is used for toner, the charge control agent adheres to the surface of the photoconductor or the adhesion of the toner on the surface of the photoreceptor is promoted due to long-term use, which may adversely affect latent image formation (filming development). ), A cleaning member such as the surface of the photosensitive member or a cleaning blade is scratched or promotes abrasion of the member, which often has a bad effect on the cleaning process of the copying machine.

Furthermore, when a conventional charge control agent is used in toner, there are not a few that greatly affect the heat melting characteristics of the toner and deteriorate the fixing performance. In particular, there are those which deteriorate the high temperature offset performance, increase the sticking property of the transfer paper to the roller at the time of heat roll fixing, and reduce the durable life of the roller.

As described above, the conventional charge control agent has many problems, and there is a strong demand in the technical field to improve them, and many improvements have been proposed so far, but they are still in practical use. Above all, the actual situation is that nothing has been found that is totally satisfactory.

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

An object of the present invention is to provide a stable triboelectric charge amount between toner particles, a toner and a carrier, a toner and a toner carrier such as a sleeve in the case of one-component development, and a triboelectric charge amount distribution is sharp. It is intended to provide a developer that is uniform and can control the charge amount suitable for the developing system used.

Still another object is a developer that faithfully develops and transfers a latent image, that is, adhesion of toner in the background area at the time of development, that is, fog and scattering of toner around the edge of the latent image, High image density is obtained,
This is to provide a developer having good halftone reproducibility.

Still another object is to provide a developer which maintains the initial characteristics even when the developer is continuously used for a long period of time and does not cause aggregation of toner or change in charging characteristics.

Still another object is to provide a developer that reproduces a stable image that is not affected by changes in temperature and humidity, especially a developer with high transfer efficiency that does not cause scattering or transfer omission during transfer at high humidity and low humidity. In offer.

Still another object is to provide a bright chromatic color developer.

Still another object is to provide a developer having excellent storage stability, which maintains the initial characteristics even after long-term storage.

Still another object is to provide a developer which can be easily cleaned in a cleaning step without causing the electrostatic latent image surface to be soiled, worn or scratched.

Still another object is to provide a developer having good fixing characteristics, particularly a developer having no problem in high temperature offset and the like.

[Means and Actions for Solving Problems] The present invention relates to a positively chargeable toner for developing an electrostatic charge image, which contains a binder resin, a colorant and a compound represented by the following general formula [I].

[Wherein R ₁ , R ₂ and R ₃ are a substituted or unsubstituted alkyl group, cyclic alkyl group, aryl group, alkylene group,
Represents an aralkyl group or a heterocyclic group, R ₁ , R ₂
And R ₃ are the same or different groups. The present inventors have found that the compound represented by the general formula [1] is thermally and temporally stable, has a low hygroscopic property, and when contained in a developer, it gives a developer having excellent electrophotographic properties. It was found to be a positive charge control agent.

The following are typical specific examples of the compound represented by the general formula [I].

(1) (2) (3) (Four) (Five) (6) (7) (8) (9) (Ten) These compounds are synthesized by known methods.

For example, the compound (1) is synthesized by the following method. Add p-tert-butyl-to phosphorus trichloride (Kishida Chemical Co., Ltd.)
Phenoxy sodium (p-tert-butylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) is reacted with sodium metal to synthesize it), and tris (p-tert-butylbenzene) phosphite is obtained.

Next, phenylmagnesium bromide was allowed to act on the above substance in ether, and tris (p-tert-butylbenzene) phosphine was obtained by the substitution reaction.

As a method of incorporating the above compound into the developer, there are 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 production method including the dispersion method, and is uniquely limited. It is not limited, but preferably 0.1 to 10 parts by weight (more preferably 0.5 to 5 parts by weight) with respect to 100 parts by weight of the binder resin.
Parts by weight). When added externally, it is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the resin.

It is also possible to use a conventionally known charge control agent in combination with the charge control agent of the present invention.

Examples of the colorant used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrolen dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6G, 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 may be used alone or in combination.

As the binder resin used in the present invention, polystyrene,
Monopolymers of styrene such as poly-p-chlorostyrene and polyvinyltoluene, and their substitution products; styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers Polymer, 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-chloromethacrylic acid Methyl 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-based copolymers such as polymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyacetic acid Vinyl, poly Tylene, 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, chlorination Paraffin, paraffin wax and the like can be used, and they can be used alone or in combination.

In addition, as the binder resin particularly suitable for pressure fixing, the following resins can be used alone or in combination as a limiting example.

Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, polytetrafluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio 5 to 30:95 to 70), olefin copolymer ( Ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, (Ionomer resin), polyvinylpyrrolidone, methyl vinyl ether-maleic anhydride copolymer, maleic acid modified phenol resin, phenol modified terpene resin.

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

As the carrier that can be used in the present invention, all known carriers can be used, for example, iron powder, ferrite powder, magnetic powder such as nickel powder, glass beads, etc., and their surfaces treated with a resin or the like. Something is included.

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

It is desirable that these ferromagnetic materials have an average particle size of about 0.1 to 2 μm.
About 20 to 200 parts by weight per 100 parts by weight, 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 an additive as required. Examples of the additive include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, fluidity imparting agents such as colloidal silica and aluminum oxide, anti-caking agents, or carbon black and tin oxide. A conductivity-imparting agent such as
Alternatively, there are fixing aids such as low molecular weight polyethylene.

To prepare the toner for developing an electrostatic charge image according to the present invention, the charge control agent according to the present invention is added with a vinyl-based or non-vinyl-based thermoplastic resin and a pigment or dye as a colorant, and if necessary, a magnetic material, and added. The ingredients are thoroughly mixed with a ball mill or other mixing machine, and then melted, kneaded, and kneaded with a heat kneader such as a heating roll, kneader, or extruder to make the resins compatible with each other. Alternatively, the dye is dispersed or dissolved, cooled and solidified, then crushed and classified to have an average particle size of 5 to 5.
20μ toner can be obtained.

Alternatively, a method in which the material is dispersed in a binder resin solution and then spray-dried, or a predetermined material is mixed with a monomer to form the binder resin to form an emulsified suspension and then polymerized A method such as a polymerization method for obtaining a toner and a toner manufacturing method can be applied.

The toners produced by these methods can all be used for development for visualizing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, etc. by conventionally known means and are excellent as follows. It has a great effect.

That is, the triboelectric charge amount between the toner particles is uniform, and the control of the electric charge amount is easy. Further, the toner is extremely stable without deteriorating during use so that the triboelectric charge amount does not vary or decrease.

Therefore, the above-mentioned obstacles such as the development fog, toner scattering, contamination of the electrophotographic photosensitive material and the copying machine are removed, and the toner of the present invention is extremely excellent. It is a toner that can withstand long-term storage without causing phenomena such as aggregation, agglomeration, and low-temperature flow, and also has excellent abrasion resistance, fixability, and adhesiveness of toner images.

The excellent effect of such a toner is that when it is used in a repetitive transfer copying system in which the operations of charging, exposing, developing, and transferring are continuously repeated, the effect is further expanded.

Further, since there is little color tone disturbance due to the charge control agent, it is possible to form a color image of excellent color when used as a color electrophotographic toner.

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

Example 1 Styrene / butyl acrylate (80/20) copolymer (weight average molecular weight _w : about 300,000) 100 parts Carbon black (Mitsubishi I 44) 10 parts Low molecular weight polyethylene wax 2 parts Compound example (1) 2 parts The materials were mixed well with a blender and then kneaded with two rolls heated to 150 ° C. After allowing the kneaded product to cool naturally, it is roughly crushed with a cutter mill, then crushed with a fine crusher using a jet stream, and further classified with an air classifier to obtain a fine powder having a particle size of 5 to 20 μ (that is, , Positively chargeable toner) was obtained.

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 μm.

Further, the triboelectric charge amount of the developer was measured by a usual blow-off method.

Next, a negative electrostatic image is formed on the OPC photoconductor by a conventionally known electrophotographic method, and this is powder-developed by the magnetic brush method using the above developer to form a toner image, which is transferred to plain paper. Heated and fixed. The obtained transferred image had a sufficiently high density of 1.28, no fog, no toner scattering around the image, and a good image with high resolution was obtained. Transfer images were continuously prepared using the above-mentioned developers and durability was examined. The transferred images after 30,000 sheets were completely achromatic images as compared with the initial images.

Further, at the time of durability, the above-mentioned filming phenomenon related to the toner on the photoconductor was not observed at all, and no problem was found in the cleaning process. At this time, there was no trouble in the fixing process, and at the end of the durability test of 30,000 sheets, the fixing machine was ticketed, but there were no scratches or damage on the roller, there was almost no stain by the offset toner, and there was no problem in practice. .

Also, when the environmental conditions were 35 ° C and 85%, the image density was
The value was 1.23, which was almost unchanged from room temperature and normal humidity, a clear image was obtained without fogging or scattering, and durability was hardly changed up to 30,000 sheets. Next, when a transfer image was obtained at a low temperature and low humidity of 15 ° C. and 10%, the image density was high at 1.37, and the solid black was developed very smoothly, and the transferred image was excellent without scattering and voids. Durability was carried out under these environmental conditions, but copying was carried out continuously and at intervals, but again the density fluctuation was ± 0.2 up to 30,000 sheets, which was sufficient for practical use.

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) was used instead of 2 parts of the compound agent (1), and development, transfer and fixing were carried out. Got the image to.

Fog was small at room temperature and normal humidity, but the image density was low at 1.06, and line drawings were scattered, and solid black was noticeable. When the durability was examined, the density decreased to 0.83 after 30,000 sheets.

Also, at the time of endurance, from around 10,000 sheets, the toner material formed a thin streak-like film on the surface of the photoconductor and appeared as lines on the image. This is so-called filming, and it is considered that the charge control agent changes the lubricity of the toner powder.

In addition, at the time of endurance, a fixed image tends to be easily caught in the fixing roller in the fixing step, and there is a difficulty in peeling off the roller.

Image density was 0.88 when images were obtained at 35 ℃ and 85%.
It became low and fog, splattering, and rubbing increased. The transfer efficiency was also low at 69%. When an image was obtained under the conditions of 15 ° C and 10%, the image density was low at 0.91, and scattering, fog, and rustling were noticeable. Although continuous images were printed, the density became 0.53 after about 30,000 sheets, making it unusable.

Example 2 Compound Example (1) A developer was obtained in the same manner as in Example 1 except that 3 parts of m-phthalonitrile was used instead of 2 parts, and development, transfer and fixing were carried out to obtain an image 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 3 A developer was obtained in the same manner as in Example 1 except that 2 parts of the compound (3) was used instead of 2 parts of the compound example (1), and development, transfer and fixing were performed, and an image was similarly obtained.

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 Example (4) was used instead of 2 parts of Compound Example (1), and development, transfer and fixing were carried out to obtain an image 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 (weight average molecular weight _W : about 300,000) 100 parts Iron trioxide EPT-500 (manufactured by Toda Kogyo) 60 parts Low molecular weight polypropylene wax 2 parts Compound Example ( 1) 2 parts The above materials were well mixed with a blender and then kneaded with two rolls heated to 150 ° C. After allowing the kneaded product to cool naturally, it is roughly crushed with a cutter mill, then crushed with a fine crusher using a jet stream, and further classified with an air classifier to obtain a fine powder having a particle size of 5 to 20 μ (that is, , Positively chargeable toner) was obtained.

Next, 100 parts of the fine powder was mixed with 0.4 parts of hydrophobic colloidal silica.
The parts were mixed by a sample mill to prepare a one-component magnetic toner.

The triboelectric charge amount of this toner was measured by a usual blow-off method.

Use this toner on a commercial copying machine (trade name NP-150Z, Canon
The image was produced by applying it to a product (manufactured by Co., Ltd.), and good results almost similar to those 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 Example (2) was used instead of 2 parts of Compound Example (1), and development, transfer and fixing were carried out in the same manner. I got an image.

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

Example 7 In the same manner as in Example 5, except that 2 parts of the compound example (3) was used instead of the compound example (1) of 2 parts, a developer was obtained in the same manner as in Example 5, and development, transfer and fixing were performed, and the same procedure was performed. I got an image.

Although the detailed results are shown in Tables 1 and 2, 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 the compound example (1) in Example 2, and an image was similarly obtained. Fog was small at room temperature and normal humidity, but the image density was as low as 0.81 and line drawings were scattered, and the solid black was noticeable. When the durability was examined, the density decreased to 0.48 after 30,000 sheets.

Further, the filming phenomenon at the time of endurance and the problem in the fixing step were almost the same as those in Comparative Example 1 and were not the same.

Image density was 0.72 when images were obtained under the conditions of 35 ℃ and 85%.
It became low and fogging, scattering, and rubbing increased, and it was not usable. The transfer efficiency was also low at 63%.
When the image was obtained under the conditions of 15 ℃ and 10%, the image density was 0.
It was as low as 73, and scatter, fog, and rubbing were noticeable. Although continuous images were printed, the density became 0.59 when 30,000 sheets were printed, making it impractical.

Example 8 Styrene / butyl acrylate (80/20) copolymer (weight average molecular weight _W : about 300,000) 100 parts Copper phthalocyanine blue pigment 5 parts Low molecular weight polypropylene wax 2 parts Compound example (1) 2 parts The above materials are blended. After being thoroughly mixed with, the mixture was kneaded with two rolls heated to 150 ° C. After allowing the kneaded product to cool naturally, it is roughly crushed with a cutter mill, then crushed with a fine crusher using a jet stream, and further classified with wind power classification to obtain a particle size of 5
~ 20μ of fine powder (i.e. positively chargeable toner) was obtained.

Further, the triboelectric charge amount of the fine powder was measured by a usual blow-off method.

Then, 100 parts of the fine powder was mixed with 50 g of magnetic particles having a particle size of 50 to 80 μm to prepare a developer.

An image was formed by using this developer by the developing method shown in FIG. 1, and a good image showing a vivid blue color was obtained. After outputting 1,500 sheets, the toner / carrier was 10 g.
Even at / 50 g, there was almost no change in the image density, and then a good image was obtained even when images were output up to 30,000 sheets while replenishing the toner.

The main developing method will be described. In FIG. 1, 1 is an electrostatic image carrier, 2 is a toner carrier, 3 is a hopper, 52 is a magnetic brush made of a magnetic particle-toner mixture, 58 is a toner thickness regulating blade, and 50 is a toner thickness regulating blade. 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 to coat the 2 evenly 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 toner layer thickness, and the toner 5 on 2 is fly-developed onto the electrostatic image on 1.

The toner thickness is controlled by the size of the magnetic brush at 52, that is, the amount of magnetic particles and the regulating blade at 58. The gap between 1 and 2 may be made larger than the toner layer thickness, and 6 may be applied with a developing bias.

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

[Effects of the Invention] The effects obtained by the present invention are as follows.

(1) A developing system to be used which has a stable triboelectric charge amount between toner particles, between toner and carrier, between a toner and a sleeve in a one-component development mixture, and has a sharp and uniform triboelectric charge distribution. It is a developer that can control the charge amount suitable for.

(2) It is a developer that can perform development and transfer faithful to a latent image, can maintain initial characteristics even when continuously used for a long period of time, and does not aggregate toner or change charging characteristics.

(3) A developer that can reproduce a stable image that is not affected by changes in temperature and humidity and that gives a bright chromatic image.

(4) Excellent storage stability over a long period of time, easy cleaning process that does not stain, wear, or scratch the electrostatic latent image surface, and has good fixing characteristics, especially high temperature offset etc. It is a developer.

[Brief description of drawings]

FIG. 1 is a schematic partial cross-sectional view for explaining an example of a developing device to which the normally charged toner according to the present invention can be applied. 1 ... electrostatic image carrier, 2 ... toner carrier, 5 ... toner, 50 ... magnet, 52 ... magnetic brush, 58 ... regulating blade.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Ikeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-59-124347 (JP, A)

Claims (1)

[Claims] 1. A binder resin, a colorant and the following general formula: [Wherein R ₁ , R ₂ and R ₃ represent an alkyl group having no substituent or having a substituent, a cyclic alkyl group, an aryl group, an alkylene group, an aralkyl group, or a heterocyclic group, and R ₁ , R ₂ And R ₃ are the same or different groups. ) A positively chargeable toner for developing an electrostatic charge image, comprising a compound represented by