JPH04177367A - Toner for electrostatic charge image development and image formation therewith - Google Patents

Abstract

PURPOSE:To control the toner to an electrification value suitable for developing method by making the toner contain a specific nitrogenous compound as a positive charge controller to make it stable in frictional electrification and sharp and uniform in frictional electrification value distribution. CONSTITUTION:It is formed with at least binding resin and a colorant, and as for the positive charge controller, a boronic compound being shown in an equation I is contained. Where, in this equation I, R1-R4 shown an alkyl group of carbon numbers 1-18, a phenyl group or benzil group. With this constitution, frictional electrification with a charge giving member such as a developing sleeve or blade, etc., can be held to frictional electrifiability where straight polarity is stabilized, and even if surroundings such as a mechanical impulse and friction plus temperature-humidity conditions and so on are changed, various capacities in the frictional electrifiability or the like will not be varied at all.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dry toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc., and an image forming method using the same. More specifically, the present invention relates to an electrostatic image developing toner containing a specific compound as a positive charge control agent and an image forming method using the same.

[Conventional technology]

There are two methods for developing electrostatic images formed on electrophotographic photoreceptors and electrostatic recording materials: a method that uses a liquid developer (wet development method), and a method that uses a colorant dispersed in a binder resin. A method (dry development method) using a toner or a one-component type or two-component type dry developer in which the toner is mixed with a solid carrier is generally adopted. Although each of these methods has its own advantages and disadvantages, the dry developing method is currently widely used.

By the way, in the above-mentioned toner (developer powder), desired charging properties cannot be obtained if colorants such as dyes and pigments are simply dispersed in a binder resin, so an appropriate amount of a charge control agent is added to the toner (developer powder). It is normal that this is done. Typical examples of conventional charge control agents include (1) agents that impart a positive charge to toner, such as nigrosine-based oil-soluble dyes;
Quaternary ammonium salts, azine dyes having alkyl groups, basic dyes, lakes of basic dyes, etc.
ii) Examples of things that impart a negative charge to the toner include metal-containing dyes such as chromium-containing monoazo complexes, chromium-containing salicylic acid compound complexes, and chromium-containing organic dyes (copper phthalocyanine green, chlorine-containing monoazo dyes).

However, toners containing these conventional charge control agents,
Although they exhibit good developing characteristics initially, they have a short lifespan, and therefore, when used for a long time, disadvantageous phenomena such as filming on the photoreceptor are often observed. This is due to the fact that the properties of conventional charge control agents are inconsistent and lack stability. In addition, many of these conventional charge control agents are easily dispersed during thermal kneading during toner production, or easily decomposed or deteriorated due to mechanical impulses, friction, changes in temperature and humidity conditions, etc. This is making the phenomenon of decline even stronger.

Furthermore, there is a tendency that many of the conventional charge control agents change depending on the environment. In particular, in a one-component process that includes at least a toner transport member and a toner layer thickness regulating member and develops by forming a thin toner layer on the toner transport member, fluctuations in toner chargeability have a large effect on the ability to form a thin toner layer. may cause image deterioration. In any case, most of the charge control agents that have been proposed so far cannot maintain appropriate chargeability over a long period of time.

[Problem to be solved by the invention]

The present invention overcomes the drawbacks of the above-mentioned prior art, and achieves stable triboelectric charging that occurs between toner particles or between a toner and a charge imparting member such as a developing sleeve or blade in a component-based development system, and Our primary objective is to provide a toner that has a sharp and uniform amount distribution and that can be controlled to the amount of charge appropriate for the developing method used, and that is positively charged over a long period of time without becoming excessively triboelectric. A second object is to provide a toner in a controlled one-component dry developer.

Furthermore, the third objective of the present invention is to provide a toner that not only always provides stable images but also has durability, is free from stains and toner scattering, and maintains the same initial image quality even during continuous use. A fourth object is to provide a toner that allows a large number of equally high-quality images to be obtained.

[Means to solve the problem]

As a result of extensive research, the present inventors have found that a toner containing a specific nitrogen compound as a positive charge control agent is suitable for the above purpose, and have completed the present invention.

That is, according to the present invention, there is provided a toner for developing electrostatic images, characterized in that the toner comprises at least a binder resin and a colorant, and contains a boron compound represented by the following structural formula (1) as a positive charge control agent. is provided.

(In the formula, R0 to R4 represent an alkyl group having 1 to 18 carbon atoms, a phenyl group, or a benzyl group.) In addition, the toner that has been made into a thin layer is supplied to the latent image carrier to develop the latent image. An image forming method using the one-component development method in photography is provided, which is characterized in that the toner is used.

In the toner of the present invention, the positive charge control agent represented by the above structural formula is synthesized by a known method. The positive charge control agent may be used alone, or 2
Seeds may also be used. Moreover, other positive charge control agents can also be used together.

The general formula (1) used as the positive charge control agent of the present invention
) Typical examples of the compounds represented by ) include the following compounds, but are not limited to these, of course.

The toner of the present invention includes a binder resin, a colorant, and the positive charge control agent as essential components. The content of the positive charge control agent in the toner is determined by the toner manufacturing method, including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. Although not necessarily limited, the amount is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the binder resin. 0
．． If it is less than 1 part by weight, the positive chargeability of the toner will be insufficient, making it impractical; if it exceeds 20 parts by weight, the positive chargeability of the toner will become too large, resulting in decreased fluidity, decreased transferability, and decreased image density. This is undesirable as it causes deterioration of the temperature.

As the colorant used in the present invention, all pigments and dyes conventionally used as colorants for toners can be used. Specifically, carbon blank, lamp blank, iron black, ultramarine blue, nigrosine dye, aniline blue, carfoil blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, phthalocyanine green, hand yellow G, rhodamine 6C lake, Examples include chrome yellow, quinacridone, quinacridone yellow, malachite green, malachite green hexalate, oil blank, azo oil blank, rose bengal, monoazo dyes and pigments, disazo dyes and pigments, trisazo dyes and pigments, and mixtures thereof. .

Further, as for the binder resin used in the present invention, all the binder resins that have been used hitherto as binder resins for toners can be used, similarly to the colorant described above. Specifically, 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 and nilnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-〇-methyl chloromethacrylate copolymer, styrene-acrylonitrile copolymer, styrene - Vinyl methyl ether copolymer, styrene-hinyl ethyl ether copolymer, styrene-hinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer , styrenic copolymers such as styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide , epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. These may be used alone or in combination of two or more.

Note that additives may be mixed with the toner of the present invention as necessary. Examples of additives include lubricants such as tetrafluoroethylene resin and zinc stearate, abrasives such as cerium oxide and silicon carbide, fluidizing agents such as colloidal silica and aluminum oxide, anti-caking agents, and carbon. Examples include a blank, a conductivity imparting agent such as tin oxide, and a fixing aid such as low molecular weight polyethylene.

The toner of the present invention is particularly useful for image formation using a one-component development method in electrophotography, and the image forming method of the present invention will be described next.

The image forming method of the present invention is an image forming method using a one-component development method in electrophotography in which a thin layer of toner is supplied to a latent image carrier to develop a latent image, and the image forming method contains the positive charge control agent described above. It is characterized by using toner. Note that toner thinning is usually achieved by providing a toner conveying member, a toner layer thickness regulating member, and a toner replenishment auxiliary member, and the replenishing auxiliary member and toner transporting member, and the toner layer thickness regulating member and toner transporting member, respectively. It is carried out using equipment that is in contact with the

The image forming method of the present invention will be explained in more detail with reference to the drawings.

The drawing is a schematic cross-sectional view of an example of a developing device using a non-magnetic-component toner useful in carrying out the method of the present invention. In the drawing, the toner 6 of the present invention contained in a toner tank 7 is forcibly brought to the toner supply member 4 by the toner replenishment auxiliary member 5, and the toner is supplied to the toner supply member 4. When the toner supply member 4 rotates in the direction of the arrow, the toner taken into the sponge roller 4 is transported to the toner conveying member 2, where it is rubbed, electrostatically or physically adsorbed, and is then transferred to the toner conveying member 2. rotates strongly in the direction of the arrow, and a uniform thin layer of toner is formed by the steel-based toner thickness regulating member 3, and is charged by friction. Thereafter, the toner is transported to the surface of the electrostatic latent image carrier 1 that is in contact with or in close proximity to the toner transport member 2, and the latent image is developed. The electrostatic latent image is created by charging the organic photoreceptor with a negative DC charge of 800 cm and then exposing it to light to form a latent image, which is then developed.

In such an image forming method using a one-component development method in electrophotography, fluctuations in toner chargeability greatly affect the ability to form a thin layer of toner, but the toner of the present invention has stable positive triboelectrification. Since the method of the present invention exhibits high properties and excellent environmental stability, it is possible to control the amount of charge to an appropriate level during implementation, and high-quality images can be obtained over a long period of time by the method of the present invention.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts represent parts by weight.

Example 1 1 part of carbon blank A mixture having the above composition was sufficiently stirred and mixed in a Henschel mixer, then heated and melted in a roll mill at a temperature of 130 to 140°C for about 30 minutes, and then cooled to room temperature. The obtained kneaded product was pulverized and classified to obtain a toner having a particle size of 5 to 10 μs.

To 100 parts of this toner, 0.3 parts of colloidal silica was added and mixed to obtain the toner of the present invention.

When the obtained toner was used to form an image using a developing device as shown in the drawing, a good image was obtained, and the image did not change even after printing 100,000 sheets.

In addition, when the amount of charge on the toner was measured using the blow-off method, the amount of charge at the initial stage was +12.7 μC/g, and the amount of charge on the toner after printing 100,000 sheets was +11.11 μC.
/g, which was almost unchanged from the initial value.

Furthermore, under a high humidity environment of 35℃ and 90% RH, and at 10℃
Even in a low humidity environment of 15% RH, an image equivalent to the original copy at room temperature was obtained, and no toner filming on the photoreceptor was observed.

Example 2 Instead of the positive charge control agent in Example 1, structural formula (1
), R□=C)13, R3=CH3, R4=C
A toner of the present invention was obtained in the same manner as in Example 1 except that the compound represented by H3, R2''Cl8837 was used.

When an image was produced using the obtained toner in the same manner as in Example 1, a good image was obtained, and the image did not change even after running 100,000 copies.

Furthermore, when the amount of charge on the toner was measured using the blow-off method, the amount of charge at the initial stage was +12.1 μC/g, and the amount of charge on the toner after running 100,000 sheets was +11.7 μC.
/g, which was almost unchanged from the initial value.

Furthermore, under a high humidity environment of 35°C and 90% RH, and at 10°C,
] Even in a low humidity environment of 5% RH, an image equivalent to that obtained in a normal humidity environment was obtained, and no toner filming on the photoreceptor was observed.

Example 3 Instead of the positive charge control agent in Example 1, structural formula (I
), R,=CH3, R2=Cl8H37, R3
A toner of the present invention was obtained in the same manner as in Example 1 except that the compound represented by =CH3, R4''Cl8837 was used.

Using the obtained toner, an image test was conducted in the same manner as in Example I, and a good image was obtained.

When the obtained toner was used to produce an image using a developing device as shown in the drawing, a good image was obtained, and the image was printed on 100,000 copies.

It didn't change after that.

Furthermore, when the toner charge amount was measured using the blow-off method, the initial charge amount was +11.3 μC/g, and the toner charge amount after running 10,000 sheets was +109 μC/g.
g was almost unchanged from the initial value.

Furthermore, under a high humidity environment of 35°C, 90% R+, and 10%
Even in a low humidity environment of 115% RH at °C, an image equivalent to the original copy at room temperature was obtained, and no toner filming on the photoreceptor was observed.

〔Effect of the invention〕

The toner for developing an electrostatic image according to claim (1) contains the nitrogen compound represented by the structural formula (1) as a positive charge control agent, so that friction between the toner and a charge imparting member such as a developing sleeve or a blade is reduced. Charging can be maintained at a positive and stable triboelectric charging property.

Further, the toner does not change its various performances such as triboelectric charging properties even if the environment such as mechanical shock, friction, temperature and humidity conditions changes.

Therefore, with the image forming method of claim (2), it is possible to obtain a high-quality image equivalent to the initial image even after continuous copying without background smudge or toner scattering.

Moreover, in this method, stable high-quality images can be obtained even under various environments, and there is no filming on the photoreceptor even after long-term use.

[Brief explanation of drawings]

The drawing is a schematic sectional view showing an example of a developing device using the non-magnetic component toner of the present invention useful for carrying out the method of the present invention. 1. Electrostatic latent image carrier, 2. Toner transport member, 3. Toner layer thickness regulating member, 4. Toner supply member, 5. Toner auxiliary replenishment member, 6. Toner, 7. Toner tank.

Claims (2)

[Claims] (1) A toner for developing an electrostatic image, comprising at least a binder resin and a colorant, and containing a nitrogen compound represented by the following structural formula (I) as a positive charge control agent. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 to R_4 represent an alkyl group having 1 to 18 carbon atoms, a phenyl group, or a benzyl group.) (2) An image forming method using a one-component development method in electrophotography, in which a thin layer of toner is supplied to a latent image carrier to develop a latent image, characterized by using the toner according to claim (1). image forming method.