JPS63226666A - Developing method using one-component type developer - Google Patents

Abstract

PURPOSE:To obtain a sharp image high in fidelity to an original through development by using a one-component type developer containing at least an organic boron compound and a magnetic material for a toner as essential components. CONSTITUTION:The one-component type developer to be used for the toner containing at least the magnetic material and the organic boron compound represented by formula I in which R1 is halogen, alkyl, haloalkyl, aralkyl, or aryl; D<+> is a cation; n is an integer of >=1; and when n is >=2, each of (R1)s may be independent of each other. As the organic boron compound, for example, tetraphenyl-B-Na is used. The toner 4 is held mainly by magnetic force on a toner carrying body 5 having a magnet roll in the inside, and conveyed to a developing zone, opposite to an electrostatic latent image bearing body 1, and the electrostatic latent image formed on the body 1 is developed with the toner 4 by an electric field formed between the body 1 and body 5 by bias voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a developing method for visualizing electrical latent images and electrical signals in electrophotography, electrostatic recording, etc., and particularly to a method that uses only toner particles without using carrier particles. Regarding component development method.

BACKGROUND TECHNOLOGY Methods for forming electrical latent images are well known. For example, in electrophotography, a photoconductor layer is usually charged and then a light image based on an original image is irradiated to form a light-irradiated area. The electrostatic charge image is reduced or eliminated to form an electrostatic latent image. Then,
This latent image is developed with a developer called toner. As a method for developing a latent image, for example, US Pat. No. 28740
Magnetic brush method described in Specification No. 63, No. 26 of the same
In addition to the cascade method described in the specification of US Pat.
Dielectric development method described in Specification No. 8, No. 3166
In addition to the touchdown method described in the specification of No. 432,
One-component development methods using only toner are known, such as charge development method, jumping method, impression method, powder cloud method, fur brush method, and the like.

Among these developing methods, the two-component developing method using a two-component developer consisting of toner and carrier is an excellent developing method that can relatively stably produce high-quality images, but on the other hand, it has problems such as deterioration of the carrier and the loss of toner and carrier. Basically, there is instability in the electrical characteristics of the developer due to fluctuations in the mixing ratio. Furthermore, it is difficult to significantly reduce the weight, space, cost, etc. of the developing device.

On the other hand, the single-component developing method that uses only toner uses a developing device with a simple configuration, and it is easy to avoid the developer deterioration that occurs in the two-component developing method, so it has been actively researched and commercialized in recent years. is being done. However, in the -component development method, since no carrier is used, it is difficult to form a uniform toner layer and control the conveyance involved in supplying the toner to the electrostatic latent image surface, and to apply and control sufficient charge to the toner. Difficulties exist.

- Conventional toners used in the component development method include so-called magnetic toners that contain magnetic materials and non-magnetic toners that do not contain magnetic materials. Magnetic toners are currently widely used because of their low internal contamination. Furthermore, magnetic toners are broadly classified into conductive toners and insulating toners depending on the form of charge imparting. In the case of conductive toner, charging is mainly caused by electrostatic induction, so while it is possible to stably control charging without being affected by the environment, it often does not transfer well to paper etc., and currently insulating toner The mainstream is one that uses toner.

Problems to be Solved by the Invention FIG. 2 shows the form of toner layer formation and transportation in a schematic diagram of a developing device used in a one-component developing method that is currently widely used. In FIG. 2(a), the toner layer is regulated by an elastic blade 71 as a toner layer regulating member, and in FIG. 2(b), the toner layer is regulated by a rigid blade (magnetic/non-magnetic) 72.
Indicates when to control. At this time, the toner 4 is often charged by contact friction between the toner layer regulating members 71 and 72 and the toner carrier 5. Therefore, in the above embodiment, in order to impart sufficient charge to the toner, it is necessary to uniformly form the toner into a thin layer. However, no matter how thin the toner layer is, there are disadvantages such as lower charging efficiency than a two-component development method using a carrier, and a charge distribution between the toners.
When developing using the above developing device, image unevenness,
Smearing, fogging, etc. often occur, and it is even more difficult to always achieve stable image reproduction against changes in the environment over time.

Conventionally, in order to improve the above-mentioned drawbacks, studies have been made on the toner itself and charge imparting members (means) such as blades and toner carriers, but they have not yet reached a sufficient level. For example, in order to impart sufficient charge to the toner, it is effective to configure the toner itself and the charge imparting member with materials that differ in terms of charge series, but what is most important is how well the charge series is determined. Even if they are far apart, the toner cannot be put to practical use unless the toner charges rise quickly. Furthermore, toner charging and transportation are closely related, and if the toner has a wide charging distribution, uneven transportation, spillage, etc. may not occur. Further, the charge of the toner must be stable against changes in the environment over time, but even when conventional so-called charge control agents are used, the level is not satisfactory. On the other hand, in order to stabilize the charge of the toner, the charge imparting member can be treated with various charge control agents, but in this case, the composition is limited from the viewpoint of processability, strength, etc. Although the reason is not clear, there are disadvantages in that the charge distribution of the toner tends to spread, and that it may adversely affect the conveyance of the toner.

Therefore, an object of the present invention is to provide a developing method that uses a -component developer to obtain a clear image that is faithful to the original.

Another object of the present invention is to provide a developing method with excellent repeat stability in image reproduction.

Still another object of the present invention is to provide a developing method that exhibits excellent image reproduction stability against environmental changes such as temperature and humidity.

Still another object of the present invention is to provide a developing method that can form good and stable images even in such image formation and processes.

Still another object of the present invention is to provide a developing method capable of forming good and stable images regardless of the nature of the organic or inorganic light-sensitive material.

Means and action for solving the problem Generally, in the case of a single-component developer that does not use a carrier, the toner charging efficiency is low, and furthermore, a constant amount of toner is transported on the toner carrier, so that a good toner layer is always maintained. However, as a result of research, the present inventors have found that it is possible to use a one-component developer containing at least a compound represented by the following general formula (I) and a magnetic material in the toner. It was found that the above-mentioned problems peculiar to one-component developers can be solved by this method, and the present invention was completed.

(In the formula, R1 is a hydrogen atom, a halogen atom, an alkyl group,
It represents a halogenated alkyl group, an arylalkyl group, or an aryl group, Do represents a cation, and n represents an integer of 1 or more. However, if n represents an integer of 2 or more, even if each of R1 is the same,
Alternatively, they may be different. ) That is, the developing method of the present invention comprises an electrostatic latent image holding member holding an electrostatic latent image on its surface, and a toner carrying member carrying a toner layer having a predetermined thickness and a predetermined amount of charge applied by a layer regulating member. , a developing method in which toner is visualized by moving toner to an electrostatic latent image holder in contact or in a non-contact manner with a certain interval in a developing section, the developing method comprising at least the above general formula (I ) and a magnetic material.

The present invention will be explained in detail below.

In the compound represented by the above general formula (I>) used in the present invention (hereinafter referred to as an organoboronant compound), R1 is a hydrogen atom, a halogen atom such as chlorine or fluorine, an argyl group such as methyl or butyl, or It is selected from organic functional groups such as halogenated alkyl groups such as fluoromethyl groups, aryl groups such as benzyl groups, phenyl groups, and tolyl groups, and arylalkyl groups.
+, Al2+ potash metal cations such as Na+, K+, Rb+, C5+, Be, Mg2+, ca2+,
It is selected from alkaline earth metal cations such as Sr and Ba2+W, metal cations such as 2+2+Ag, C1,l, Zn, and Qd''+l, and organic cations such as amine, ammonium, pyridinium, and phosphonium.

A typical organic boron compound in the present invention is represented by the following general formula (n).

(In the formula, R2 represents a hydrogen atom, a halogen atom, a lower alkyl group, or a trifluoromethyl group, R3 represents a hydrogen atom or a trifluoromethyl group, and D represents a cation.) These organic boron compounds For example, the following are exemplified.

Tetraphenyl Sodium Boron Tetraphenyl Potassium Boron Tetraphenyl Ammonium Boron Tetraphenyl Lithium Boron Tetraphenyl Rubidium Tetraphenyl Silver Tetra (p-fluorophenyl) Sodium Tetra (p-fluorophenyl) -chlorophenyl) boronate potassium tetraphenyl boronate cesium tetrakis [3,5-bis(trifluoromethyl) In the basic invention, the organic boronate compound may be a single compound, but may be two or more types. The compounds may be mixed or dissolved in solid solution.

The above-mentioned organic boronate compound is added to the toner, but its particle size is 5 μm or less, preferably 1 μm or less, and sufficient effects can be obtained with the addition amount of 0.01% to 5% by weight. , preferably 0.1% to 3% by weight.

The above-mentioned organoborine compound may be added to the toner as an internal additive, or, for example, may be added to the toner and mixed and attached directly to the toner particle surface, or the toner may be added to the toner as an internal additive. A surface coated inorganic fine powder, organic fine powder, etc. used as a cleaning agent, a cleaning aid, etc. may be mixed with the toner and adhered to the toner. Furthermore, most of the organic borosilicate compounds in the present invention are colorless, which makes them advantageous for application to color magnetic toners.

In the present invention, the magnetic material used in the toner includes known magnetic materials, such as metals such as iron, cobalt, and nickel, and alloys thereof, gold@oxides such as Fe3O4, γ-Fe2O3, and cobalt-added iron oxide, and Ferrite powders such as MnZn ferrite, NiZn ferrite, and Zn ferrite can be used.

These magnetic powders can be selected as either granular powder or acicular powder depending on the purpose, and granular magnetic powder with a particle size of about 0.01 μm to 2 μm, particularly preferably about 0.1 μm to 1 μm. is easy to use. These magnetic powders can be used as necessary with surfactants, long-chain fatty acids and their derivatives, silane coupling agents, titanate coupling agents, or polar functional groups such as 1000H groups, -OH groups, -NH2 groups, etc. After surface treatment with oligomers, polymers, etc. having groups, or by performing a polymerization reaction on the surface of the magnetic material powder to coat the surface of the magnetic material with a polymer component, it is added and mixed into a binder resin. Good too.

The content of the magnetic material varies depending on the developing method etc. or the specific gravity of the magnetic material powder, but it is 15 to 70% based on the binder resin.
It is preferably used in a range of 30% by weight, more preferably 30% by weight.
It is used in a range of 60% by weight.

The binder resin used in the toner in the present invention includes known resins, such as styrene resins, acrylic resins, olefin resins such as polyethylene, diene resins such as butadiene and isoprene, polyesters, epoxy resins,
Synthetic resins such as fluororesins, silicone resins, phenol resins, petroleum resins, and polyurethanes, as well as natural resins, can be used.

Further, in order to adjust the color tone, the toner may further contain known dyes and pigments as colorants. For example, any dye or pigment can be used, such as carbon black, nigrosine, aniline blue chrome yellow, ultramarine blue, methylene blue chloride, phthalocyanine blue, disazo yellow, and rhodamine 6G lake.

It is also possible to add an appropriate amount of a fluidity imparting agent such as colloidal silica to the toner as an additive for increasing the fluidity of the toner.

For the purpose of improving the above-mentioned electrical properties and storage stability, etc., including the powder flowability of the toner, or for the purpose of preventing toner filming on the photoreceptor or improving the cleanability of the toner. Additionally, other external additives may also be used.

Such additives include long-chain fatty acids such as stearic acid and their esters, amides, and metal salts, aromatic acids such as terephthalic acid and their esters, amides, and metal salts, as well as tin oxide and butylated graphite. , silicon carbide, boron nitride,
Silica, aluminum oxide, titanium dioxide, zinc oxide,
Fine powder of zirconium oxide, etc., fine powder of fluororesin, acrylic resin, etc., polycyclic aromatic compound, waxy substance, crosslinked or non-crosslinked resin fine powder, etc. can be used.

FIG. 1 is a schematic diagram of a developing device for carrying out the present invention. In FIG. 1, a developing machine body 2 installed near the electrostatic latent image holder 1 has a hopper 3 having an opening on the side of the electrostatic latent image holder 1. In addition to containing the toner 4, a toner carrier 5 whose portion projects toward the electrostatic latent image carrier 1 from the opening is also accommodated in the lower part of the hopper 3. The toner carrier 5 is
It consists of a roll with a smooth or moderately uneven surface and a magnet roll 9 arranged inside, and at least one of the toner carrier 5 or the magnet roll 9 is driven by a drive system (not shown) in the direction of the arrow or in the opposite direction to the arrow. rotated to Further, a bias power supply 6 applies a DC and/or AC bias voltage as necessary. Further, a mechanical layer regulating member is provided on the toner carrier 5 to control the uniform application of toner particles in a thin layer. Layer regulating member 7
consists of an elastic blade, a rigid plate, etc., and can perform layer regulation as well as imparting electrical charges through contact with the toner 4, friction, and the like. Further, the toner charge can also be adjusted by ion irradiation or the like. In this case, it is preferable to use a material for the layer regulating member 7 that is located at an appropriate distance from the toner 4 on the charging series. A DC and/or AC power source 8 is connected to the layer regulating member 7 as required, so that an electric field is generated between the toner carrier 5 and the layer regulating member 7. This electric field transmits minute vibrations to the toner 4 sandwiched between the toner carrier 5 and the layer regulating member 7, thereby preventing a decrease in the fluidity of the toner and creating a uniform thin layer of toner on the toner carrier. In addition to being advantageous in layer formation, it may also be advantageous in that it can exert an amplification effect or a charge injection effect when applying charges due to contact or friction.

In the developing device having the above configuration, - the toner 4 formed into a thin layer by the regulating member 7 is carried and conveyed mainly by magnetic force on the toner carrier 5, reaches the developing area, and reaches the electrostatic potential. It either contacts the image carrier 1 or faces the image carrier 1 with a small gap in a non-contact state. As a result, the toner 4 is transferred to the electrostatic latent image by an electric field formed between the electrostatic latent image holding member 1 and the toner carrying member 5 due to the DC and/or AC bias voltage applied as necessary. It is deposited according to the pattern and developed.

Effect According to the present invention, by adding the above-mentioned organic boron compound,
A uniform thin layer formation, transportation, and charging of the toner on the toner carrier are improved. Further, the developer used in the present invention is a magnetic toner, and exhibits good characteristics in both charge injection type and triboelectric charging type (charging by a charge imparting member or mutual charging of toner particles).

The mechanism of action of the above-mentioned organic compound in the present invention is not necessarily clear, but (a) electron-accepting property of boron, (b) neutralized salt type structure, and (C) formation of boron anion due to resonance effect of phenyl group. Stabilization, (d> Excellent charge exchangeability with magnetic materials, etc., which promotes the exchange and movement of electrons and/or ions on the toner surface and in the toner, resulting in good charging efficiency and small charge distribution. As a result, it is presumed that this is to stably control the charging/transportation of toner.

EXAMPLES Hereinafter, the present invention will be explained by examples, but of course the content of the present invention is not limited only to these examples.

Note that "parts" in steel represent "parts by weight" unless otherwise specified.

Example 1 Styrene/n-butyl meth 100 parts acrylate (70/30) copolymer (number average molecule ml'ln: about 15,000, weight average molecule iJ Nn: about 40,000 > magnetite (particle size 0)
．． 3 μm) 90 parts Sodium tetraphenyl boronate 1 part The above valve was melt-kneaded using a roll mill, coarsely pulverized using a hammer mill, finely pulverized using an air jet system, and further classified to obtain a toner having an average particle size of 12 μm. Hydrophobic silica (R-97
2, manufactured by Nippon Aerosil Co., Ltd.) was added in an amount of 0.5% by weight, and the mixture was stirred using a high-speed mixer to obtain a developer.

Development was carried out using the obtained developer under the following conditions.

That is, the developing device shown in FIG. 1 is arranged in a copying machine (a modified FX-2300 manufactured by Fuji Xerox), the above developer is put into the hopper 3 of the developing device, the magnet roll 9 is fixed, and the toner carrier is placed in the hopper 3 of the developing device. 5 was subjected to rotational close-up development in the with mode. In the above-mentioned developing device, the toner carrier 5 is made of a phenol resin in which graphite is dispersed and the electrical resistivity is controlled to about 109 Ω·crn, and the magnet roll 9 has a resistivity of 650 gauss under the layer regulating member 7. ,
Five poles of 850 Gauss at the portion facing the electrostatic latent image holder and 700 Gauss at the other portions were used, and the angle between the poles was 72°. The layer regulating member 7 is made of modified silicone rubber coated with a thickness of 11 nm on a stainless steel blade with a thickness of O, im.
A material coated with Iri was used. Further, the layer regulating member 7 applies approximately 150 cJ to the toner carrier 5.
The contact was made with a pressure of /cm. The development conditions when performing close-up development in the with mode are: distance between toner carrier and latent image carrier @ 200μ; toner carrier circumferential speed 100m/
sec, and the developing bias is 300V for DC component and 2.4kVI for AC component)-1) (2,5
KHz) was applied.

The image obtained by development under a normal temperature and normal humidity environment (22° C., 65% RH) was clear with excellent resolution and no fog. When the chargeability of the toner on the toner carrier at this time was measured using a charge spectrum method, the average charge amount of the toner was -6.5μC/g, and the reverse polarity toner was ff12.0wt.
%, which was good. Even when image reproduction was repeated on 5000 sheets using the above developer, stable image quality could be maintained.

In addition, when developing in a high temperature and high humidity environment (30°C, 85% RH), image quality was almost the same as that in a normal temperature and humidity environment (22°C, 65% R11), and even after 3000 image reproduction cycles. , there was almost no change.At this time, the average charge amount and the amount of reverse polarity toner were −
It was 6.0 μG/9 and 1.5 wt%, and hardly changed over time.

Next, we looked at image reproducibility in a low-temperature, low-humidity environment (10°C, 15% RH) and found that it was a normal temperature and humidity environment (22°C, 65% R
A good image similar to H) was obtained. Furthermore, even when the image reproduction operation was repeated for 3000 images under these environmental conditions, good image quality without fogging could be maintained. At this time, the average charge amount and the amount of reverse polarity toner are also stable.
They were -6.5 μC/and 2.3 wt%, respectively.

Example 2 The developer of Example 1 was placed in the developing device shown in FIG. 2(b) and evaluated under the same conditions as Example 1.

At this time, an aluminum sleeve is used as the toner carrier, and a magnetic blade is used as a layer regulating member, and the distance between the magnetic blade and the toner carrier is 0.3M. A magnetic brush was formed between the toner carriers to control the layer.

In this example as well, a clear and good image without fogging was obtained. The average charge amount and the amount of reverse polarity toner at this time were -6.0 μC/g and 1.2 wt%, respectively. In addition, the environment was changed in the same way, and 50
When 00 continuous images were reproduced, stable and good image quality could be maintained.

Comparative Example 1 In Example 1, 1 part of a chromium-containing dye was added instead of sodium tetraphenyl boronate, and a toner having an average particle size of 12 μm was obtained by the same manufacturing method as in Example 1. To the above toner, 0.5% by weight of hydrophobic silica (R-972> was added and stirred with a high-speed mixer to prepare a developer. This developer was processed using the same developing device as in Example 1 under the same conditions. When the image was evaluated, a relatively good image was obtained although there was some fogging.The average charge amount and the amount of reverse polarity toner were -5, 8μC/9 and 8μC/9, respectively.
．． It was 2wt%.

Furthermore, when repeated image review +i was performed, 200
With 0 sheets, fogging and image blurring became noticeable and the image quality was quite low. At this time, the average charge amount and reverse polarity toner amount are -4,8μC/7 and 18.3wt, respectively.
%Met.

Next, this developer was applied in a high temperature and high humidity environment (30'C85%R
When image reproduction was evaluated for H), defects such as thickening of thin lines and fogging were noticeable. The average charge amount and reverse polarity toner amount at this time are -2,0 μG/
They were 9 and 20.0 wt%. Furthermore, a low temperature and low humidity environment (
When the image reproducibility was examined at 10° C. (15% RH), the obtained image was of low quality with low image density and considerable t5J distortion. The average charge amount and reverse polarity toner amount at this time are -6, 3 μC, /9 and 17, respectively.
．． It was rare at 3wt%.

Comparative Example 2 In Example 1, a toner having an average particle size of 12 μm was produced without adding sodium tetraphenyl boronate.

To this toner, 0.0% hydrophobic silica (R-972) was added.
5% by weight was added and stirred with a high speed mixer to obtain a developer. When this developer was subjected to image reproduction evaluation under the same conditions as in Example 1, a low-quality image with noticeable fogging and image bleeding was formed. At this time, the average charge amount and reverse polarity toner amount are -3.0μG/9 and 12.3w, respectively.
It was t%.

In addition, using this developer, under a high temperature and high humidity environment (30℃ 85℃)
%RH), image reproduction evaluation was performed, and it was found that image correction,
Fogging etc. were noticeable and it was not suitable for practical use.

Example 3 In Example 1, tetraphenyl is sodium boronate.
1 part each a) Potassium tetraphenyl boronate 1 part b) Tetra (p-fluorophenyl) 1 part Sodium boronate C) Tetra (p-chlorophenyl) 1 part Potassium boronate d) Tetraphenyl boronate One part of ammonium or e) tetraphenyl was replaced with one part of cesium boron, and a toner having an average particle size of 12 μm was obtained in the same manner. To this, hydrophobic silica (R-972>0.5% by weight) was added and developers 3a, 3b, 3c, 3d, and 3e were obtained in the same manner.

Image reproduction evaluation was performed on the five types of developers mentioned above under the same conditions as in Example 1, and all toners exhibited good image quality regardless of the environment and aging. The data on the chargeability of each developer at that time is shown in the table.

Example 4 Polyester resin 100 parts ()In
:200OS) 1w:8000) Magnetite (particle size 0
．． 3 μm>90 parts Potassium tetraphenyl boronate 1 part A toner having an average particle size of 12 μm was obtained in the same manner as in Example 1 using the above components. Hydrophobic silica (R-972>0.5% by weight was added to this toner and stirred with a V-type mixer to obtain a developer. Using this developer, evaluation was performed under the same conditions as in Example 2. As a result, clear images with no fog were obtained.Furthermore, repeatability, including environmental variations, was stable.

Example 5 Styrene/n-butyl meth 100 parts acrylate copolymer (Mn: about 15,000, iw: about 40,000)
90 parts of γ-hematite 1 part of cyan pigment (Sudan blue, (
C, 1, Pigment Blue 15-3) ) Potassium tetraphenylboron 1 part A toner having an average particle size of 12 μm was obtained in the same manner as in Example 1 using the above ingredients. For this toner, hydrophobic silica (R-9
72>0.5% by weight was externally added and mixed to prepare a developer. When image reproduction evaluation was carried out using this developer under the same conditions as in Example 2, a clear sepia image with excellent resolution and no fog was obtained. In addition, repeatability, including environmental changes, was stable and rare.

Example 6 Styrene/butyl acrylate 40 parts copolymer (
Mn: approx. 5,000, HW: approx. 20,000) Styrene/butadiene crosslinked polymer 60 parts (gel fraction ≧ 60%) Polypropylene wax 4 parts Magnetite (particle size 0.3 μm) 90 parts Tetraphenylborocesium 1 part Above components Example 1
A toner having an average particle size of 12 μm was obtained in the same manner as above. For this toner, hydrophobic silica (R-972>0.5
A developer was obtained by externally adding and mixing 0.2% by weight of polymethyl methacrylate fine powder (prepared to 0.3 μm by soap-free polymerization method). Put this developer into FX-2700,
When a reverse image reproduction evaluation was performed, good image quality with no fogging or image bleeding was obtained.

Example 7 Styrene/butyl acrylate 100 parts (65/
35) Copolymer ()In: about 15,000, )1w: about 40,000
) Magnetite (particle size 0.3 μm> 90 parts Tetraphenyl potassium boronate 1 part Using the above ingredients, a toner with an average particle size of 12 μm was obtained in the same manner as in Example 1. To this toner, carbon black ( Particle size o, o2 s μm, 1) H=8) 0.5% by weight were externally added and mixed to obtain a developer. Using the obtained developer, development was carried out under the following conditions.

That is, the developing device of Example 2 was replaced with a brass blade in place of the magnetic blade and the distance between the toner carrier blades was set to 0.58, and the magnetic roll and toner carrier were scented with the same aroma. Each
Rotate at 50 rpm and 90 rpm, FX-2300
Contact development was carried out using a modified machine (manufactured by Fuji Xerox 0-Shu).

At this time, the distance between the toner carrier/latent image carrier is 0.6I.
rI! It was set to rI.

When image reproduction was evaluated on 5,000 sheets in the same manner as in Example 1, extremely stable image quality without fogging or blurring could be maintained under any environment.

Example 8 Styrene/ethylene wax (90/10) 70 parts co-polymer ethylene/vinyl acetate copolymer 20 parts ethylene wax 10 parts magnetite
A toner having an average particle size of 12 μm was obtained in the same manner as in Example 1 using 100 parts potassium tetraphenylboride and 1 part the above components. To this toner, add hydrophobic silica (R-972>0.5 wm%,
The mixture was stirred and mixed using a high-speed mixer to prepare a developer. This developer was developed using the same developing machine as in Example 2 under the same conditions, and was further pressure-fixed using a metal roll with a linear pressure of 20 Kff/cm to evaluate the image. As a result, a good image was obtained with no fogging or bleeding. was gotten.

Example 9 In Example 8, a toner having an average particle size of 12 μm was prepared without adding potassium tetraphenyl boronate. For this toner, tetraphenyl potassium boron 0.1
After adding % by weight and fixing it to the toner using a high-speed mixer,
A developer was obtained by adding hydrophobic silica (R-972>0.5 mm% and further mixing with external additives). When this developer was subjected to image evaluation under the same conditions as in Example 8, it was found that there was no fogging or bleeding. A clear and good image was obtained.

Effects of the Invention In the present invention, since a one-component developer containing at least the above-mentioned organic boronate compound and a magnetic material is used, uniform N layer formation, transport and charging of the toner on the toner carrier are improved. Become. Therefore, according to the present invention, a clear image that is faithful to the original can be obtained, and the present invention also has excellent repeat stability of image reproduction and excellent stability against environmental changes such as temperature and humidity. Depends on the developing method.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a developing device for carrying out the present invention, and FIGS. 2 (a> and (b) are schematic diagrams of a developing device used in a -component development method, respectively. 1.・Electrostatic latent image holder, 2...Developing machine body, 3...
・Hopper, 4... Toner, 5... Toner carrier,
6... Bias power supply, 7... Layer regulating member, 8...
Power supply, 9...magnetic roll.

Claims (2)

[Claims] (1) An electrostatic latent image holding member holding an electrostatic latent image on its surface and a toner carrying member carrying a toner layer having a predetermined thickness and a predetermined charge amount by a layer regulating member are brought into contact or In a developing method of forming a visible image by moving toner to an electrostatic latent image holder at a fixed interval and facing each other in a non-contact state, at least the following general formula (I
) A developing method characterized by using a toner containing a compound represented by (a) and a magnetic material. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 represents a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an arylalkyl group, or an aryl group, and D^■ represents a cation. n represents an integer of 1 or more. However, when n represents an integer of 2 or more, each R_1 may be the same or different.) (2) The developing method according to claim 1, wherein the compound contained in the toner is represented by the following general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R_2 represents a hydrogen atom, a halogen atom, a lower alkyl group, or a halogenated methyl group, R_3 represents a hydrogen atom or a halogenated methyl group, and D^ ■ represents a cation.)