JPH03280069A - Toner for electrostatic charge development and image forming method using the toner - Google Patents

Abstract

PURPOSE:To provide a stable frictional electrification and a sharp and uniform frictional electrification distribution and to allow the control to the charge quantity suitable for the developing method to be used by incorporating a specific zinc compd. as negative charge control agents into the toner. CONSTITUTION:At least one kind of the zinc compds. expressed by formulas I and II are incorporated as the negative charge control agent into the toner. In the formulas, at least one of R1 to R10 denote an alkyl group or alkoxy group; at least one of R11 to R20 denote a alkyl group or alkoxy group respectively; the other Rs denote a hydrogen atom, alkyl group or alkoxy group. At least one of R21 to R25 denote an alkyl group or alkoxy group; at least one of R26 to R30 denote an alkyl group or a alkoxy group, respectively, and the other Rs denote a hydrogen atom, alkyl group or alkoxy group. The stable frictional electrification chargeability of a negative polarity is exhibited in this way and since environmental stability is excellent, the control to the adequate charge quantity at the time of execution is possible.

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. Specifically, the present invention relates to an electrostatic image developing toner containing a specific zinc compound as a negative 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 using a liquid developer (wet development method), and a method using 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 11!1J additives include (i) agents that impart a positive charge to the toner, such as nigrosine oil-soluble dyes, quaternary ammonium salts, azine dyes having alkyl groups, and bases; chromium-containing monoazo complexes, chromium-containing salicylic harsh compound complexes, chromium-containing organic dyes (copper phthalocyanine green, chlorine-containing monoazo dyes), etc. ) and metal-containing 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. There is also 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]

Therefore, the present invention overcomes the drawbacks of the above-mentioned prior art, and provides stable frictional 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. Our first objective is to provide a toner that has a sharp and uniform triboelectric charge distribution and can be controlled to a charge amount suitable for the developing method used.
A second object of the present invention is to provide a toner in a one-component type dry developing material that is negatively charged over a long period of time without becoming excessively triboelectrically charged.

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 zinc compound as a negative charge control agent is suitable for the above purpose, and have completed the present invention.

That is, according to the present invention, in a toner comprising at least a binder resin and a colorant, at least one of the zinc compounds represented by the following general formulas (1) and (II) is used as a negative charge control agent.
A toner for developing an electrostatic image is provided, the toner containing a seed.

(In the formula, at least one of R to R□ represents an alkyl group or an alkoxy group, and at least one of R to Rzo represents an alkyl group or an alkoxy group, and the other R
represents a hydrogen atom, an alkyl group or an alkoxy group. ) (In the formula, at least one of R2□ to Ftzs represents an alkyl group or an alkoxy group, and at least one of RAG to R3 represents an alkyl group or an alkoxy group, and the other R's are hydrogen atoms, alkyl groups, or (Represents an alkoxy group.) Further, the toner is used in 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. An image forming method is provided.

In the toner of the present invention, the zinc compounds represented by the general formulas (1) and (If) used as negative charge control agents are synthesized by known means. These negative charge control agents may be used alone or in combination of two types. Moreover, other negative charge control agents can also be used together.

The toner of the present invention includes a binder resin, a colorant, and the negative charge control agent as essential components. The content of the negative 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, it is usually in the range of 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 negative chargeability of the toner will be insufficient, making it impractical; if it exceeds 20 parts by weight, the negative 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 black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, calco oil blue DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6C lake, chromium. Yellow, quinacridone, benzidine yellow, malachite green, malachite green hexalate, oil black, azo oil black, 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 poly-P-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 acid ester copolymers: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin , polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. or a mixture 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 conductivity imparting agents such as black, tin oxide, and fixing aids 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 above-described negative charge control agent. It is characterized by using toner. Note that toner thinning is usually achieved by including a toner conveying member, a toner layer thickness regulating member, and a toner supplying member, and in which the toner supplying member and toner conveying member and the toner layer thickness regulating member and toner conveying member are in contact with each other. It is carried out using the same equipment.

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 a toner supply member (sponge roller) 4 by a stirring blade (toner supply auxiliary member) 5. Supplied. When the toner supply member 4 rotates in the direction of the arrow, the toner taken into the toner supply member 4 is transported to the toner transport member 2, where it is rubbed, electrostatically or physically attracted, and is then transferred to the toner transport member 2. 2 is strongly rotated in the direction of the arrow, and a uniform thin layer of toner is formed by a steel toner layer thickness regulating member (elastic blade) 3 and frictionally charged. 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 one in which an organic photoreceptor is charged with a negative DC voltage of 800 μm and then exposed to light to form a latent image, which is then reversely developed. Note that developing devices suitable for the toner of the present invention are not limited to those described above.

In image forming methods using one-component development 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 negative 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 1 part represents a part by weight.

Example 1 In the general formula (1), R2, R,, R1□ and R
A mixture consisting of 3 parts of a compound in which 19 is a methyl group and all other R's are hydrogen atoms, 100 parts of a styrene/n-butyl methacrylate copolymer, and 10 parts of carbon black was sufficiently stirred and mixed in a Henschel mixer. rear,
The mixture was 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 resulting mixed material was crushed and classified to obtain a toner having a particle size of 5 to 10 liters. 0.2 parts of colloidal silica was added to 100 parts of this toner 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 running 100,000 copies.

In addition, when the toner charge amount was measured using a suction method, the initial charge amount was -13.2 μC/g, and the toner charge amount after running 100,000 sheets was -12.8 μC/g, which was almost the initial value. It didn't change.

Furthermore, under a high humidity environment of 35℃ and 90% RH, and at 10℃
.

Even in a low humidity environment of 15% R11, 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 compound represented by the general formula (I) in Example 1, R3, R
6. Except for using a compound in which R>3 and R18 are tert-butyl groups, and all other R are hydrogen atoms,
A toner of the present invention was obtained in the same manner as in Example 16. When an image was produced in the same manner as in Example 1 using the obtained toner, a good image was obtained, and the image was printed on 100,000 copies. It didn't change after running.

Furthermore, when the toner charge amount was measured using a suction method, the initial charge amount was -10.3 μC/g, and the toner charge amount after running 100,000 sheets was -10.1 μC/g.
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 15% 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 compound represented by the general formula (1) in Example 1, in the same general formula (1), R3 and R are ethyl groups, and all other R are hydrogen atoms. A toner of the present invention was obtained in the same manner as in Example 1 except that the compound 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.

In addition, when the toner charge amount was measured using a suction method, the initial charge amount was -13.1 μCog, and the toner charge amount after running 100,000 sheets was -12.8 μC/g, which was almost unchanged from the initial value. Ta.

Furthermore, under a high temperature environment of 35℃, 90% R1 (and 10℃
Even in a low humidity environment of 15% RH, an image equivalent to that obtained in a normal temperature environment was obtained, and no toner filming on the photoreceptor was observed.

Example 4 Instead of the compound represented by the general formula (summer) in Example 1, RZJ and R
A toner of the present invention was obtained in the same manner as in Example 1, except that a compound in which 2, and R were methyl groups and all other R were hydrogen atoms 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 remained unchanged even after running 10,000 sheets. When measured by a suction method, the initial charge amount was -13.4 μC/g, and the charge amount of the toner after running 100,000 sheets was -12.9 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 under 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 5 Instead of the compound represented by the general formula (1) in Example 1, -Lx and R□ in the general formula (II)
A toner of the present invention was obtained in the same manner as in Example 1, except that a compound in which 7 was a tert-butyl group and all other R were hydrogen atoms 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.

In addition, when the toner charge amount was measured using a suction method, the initial charge amount was -11.5 μC/g, and the toner charge amount after running 100,000 sheets was -10.9 μC/g, which was almost the initial value. It didn't change.

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

Example 6 In place of the compound represented by the general formula (1) in Example 1, in the general formula (II), R24 and L
A toner of the present invention was obtained in the same manner as in Example 1, except that a compound in which s was an ethyl group and all other R were hydrogen atoms 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 toner charge amount was measured using a suction method, the initial charge amount was -10.9 μC/g, and the toner charge amount after running 100,000 sheets was -10.6 μC/g, which was almost the initial value. It didn't change.

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

Comparative Example Except for using copper phthalocyanine green instead of the compound represented by the general formula (I) in Example 1,
A comparative toner was obtained in the same manner as in Example 1.

When an image test was conducted using the obtained toner in the same manner as in Example 1, a clear image with no fog was obtained at the beginning, but after about 5,000 copies, the image became unclear with fog, and the photosensitive Toner filming was observed on the body surface. Furthermore, under high temperature and high humidity conditions, the image density was as low as 0.9. When the charge amount was measured in the same manner as in Example 1, the initial charge amount was -10.0 μC/g, which was sufficient, but after running 5,000 sheets, it decreased to -3.9 μC/g. .

〔Effect of the invention〕

The toner for developing an electrostatic image according to claim (1) contains at least one of the zinc compounds represented by the general formulas (I) and (II) as a negative charge control agent. Frictional charging with a charge imparting member such as a blade can be maintained at a stable negative polarity.

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.

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

[Brief explanation of the drawing]

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... Stirring blade, 6... Toner, 7... Toner tank.

Claims (2)

[Claims] (1) In a toner consisting of at least a binder resin and a colorant, the negative charge control agent is expressed by the following general formulas (I) and (II).
) A toner for developing an electrostatic image, comprising at least one zinc compound represented by the following. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, at least one of R_1 to R_1_0 is an alkyl group or an alkoxy group, and R_1_1 to R_2
At least one of _0 represents an alkyl group or an alkoxy group, and the other R represents a hydrogen atom, an alkyl group, or an alkoxy group. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, at least one of R_2_1 to R_2_5 is an alkyl group or an alkoxy group, and R_2_6 to R
At least one of _3_0 represents an alkyl group or an alkoxy group, and the other R represents a hydrogen atom, an alkyl group, or an alkoxy 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.