JPH06313994A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To provide a white or practically colorless electrophotographic toner excellent in stability to mechanical friction and shock and stability to temp. and humidity, giving a clear image and capable of continuous use. CONSTITUTION:This electrophotographic toner contains a compd. represented by the formula as an electric charge regulating agent. In the formula, each of R1 and R4 is H, alkyl or an optionally substd. arom. (condensed) ring, each of R2 and R3 is an optionally substd. arom. (condensed) ring, M is a trivalent metal and X<n+> is a cation.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to toners for developing electrostatic latent images in electrophotography.

[0002]

2. Description of the Related Art In electrophotography, a latent image is formed on a photoconductor made of a photoconductive substance or the like, and the latent image is developed with a powder developer to visualize the latent image. Is generally fixed on paper by pressure.
As such an electrophotographic developer, a two-component system developer comprising a mixture of a toner in which a colorant, a charge control agent, a fluidizing agent, etc. are dispersed in a natural resin or a synthetic resin and a carrier of iron powder or ferrite powder The agent can be roughly classified into a colorant, a charge control agent, a fluidizing agent, and a one-component type developer made of a magnetic material in natural resin or synthetic resin.

The two-component developer achieves development by attaching toner charged by friction with a carrier to an electrostatic latent image. As a one-component developer,
Conventionally, a toner charged by friction with a brush-like or plate-like friction member having a similar function to that of the carrier has been known, and recently, a magnetic fine powder is dispersed in a dispersed state. Toners that have been kept and charged by mutual friction with the magnetic fine powder have become known. The photoconductor layer can be positively or negatively charged so that exposure under the original gives a positive or negative electrostatic latent image. Depending on the polarity of this electrostatic latent image, the developing toner is
Keeps positive or negative.

In order to maintain the electric charge in the toner, it has been proposed to utilize the triboelectric chargeability of the resin which is the main component of the toner, but in this method, the electric charge of the toner is small and the solid surface resistance value is small. Since it is large, the obtained image is easily fogged and becomes unclear. Therefore, in order to impart a desired triboelectrification property to the toner, a dye, a pigment or a charge control agent which imparts an electric charge has been added, and it has been put into practical use in the technical field today.

However, the dyes and pigments as charge control agents have a complicated structure and poor stability, and are decomposed or deteriorated by, for example, mechanical friction and impact, temperature and humidity changes, electrical impact and light irradiation. Therefore, the charge adjusting ability is easily lost. Further, since it is a colored substance, it has an essential defect that it cannot be used for a toner having a specific hue.

Further, many of these dyes and pigments have a low compatibility with the resin for toner and therefore have a poor dispersibility,
When pulverized after melt-kneading, the components in the obtained individual toner particles become non-uniform, the charge amount on the toner surface becomes uneven, and in some cases even particles consisting of only dyes or pigments are present. As a result, the obtained image is fogged, the quality is deteriorated with the number of times of copying, the toner is scattered around the edge of the latent image, and the carrier is contaminated.

[0007]

SUMMARY OF THE INVENTION A general object of the present invention is to provide a new technique for controlling the charge of a toner which overcomes the above problems, is excellent in compatibility with a resin, and has a triboelectric charge amount. It is an object of the present invention to provide a toner that is stable and has a good start-up, has a sharp triboelectric charge amount distribution and is uniform, and that can control the charge amount suitable for the system to be used. Another object is to provide a stable chromatic color toner that reproduces a stable image that is not affected by changes in temperature and humidity. Another object of the present invention is to provide a toner having excellent long-term storage stability, maintaining initial properties even during continuous copying, and showing no deterioration in charging properties.

[0008]

Means for Solving the Problems The present inventors have found that they have good compatibility with resins, have thermal stability up to a temperature at which melt-kneading can be sufficiently performed, and are colorless substances suitable for toner. Found a compound that can impart a negative charge,
The present invention has been completed.

That is, the present invention is an electrophotographic toner containing a compound represented by the general formula <A> as a charge control agent.

[0010]

[Chemical 1]

In the formula, R ₁ and R ₄ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and R ₂ and R ₃ represent a substituted or unsubstituted aromatic ring ( (Including a condensed ring), M represents a trivalent metal, and X ^{n +} represents a cation.

Regarding the compound represented by the general formula <A>,
The details will be described below.

Examples of the alkyl group for R ₁ and R ₄ include a methyl group, an ethyl group, an n-butyl group, an iso-amyl group, an n-dodecyl group, an n-octadecyl group and a cyclohexyl group. Examples of the aromatic ring of R ₁ , R ₂ , R ₃ and R ₄ include a benzene ring and a naphthalene ring. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, an aryl group, an aralkyl group, a nitro group and a cyan group.

Further, M is C which is a trivalent metal.
r, Al, Fe, Co, Ti, B and the like are included.

Various inorganic cations and organic cations can be used as X ^{n +} . Examples of the inorganic cations include hydrogen ions and metal ions, which are monovalent or divalent.
Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca as valent metal ions
²⁺ , Zn ^{2+, and the} like. Examples of the organic cation include ammonium ion, iminium ion, phosphonium ion and the like.

Preferred among the above organic cations are those represented by the following general formula <B>, <C>, <D> or <E>.

[0017]

[Chemical 2]

In the formula, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ ,
R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ each represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and Z ₁ and Z ₂ are each represented by The non-metallic atomic group which couple | bonds with a nitrogen atom and forms a 5-membered ring or 6-membered ring is shown.

Examples of the alkyl group include methyl group, ethyl group, n-butyl group, iso-amyl group, n-dodecyl group, n-
Examples thereof include octadecyl group and cyclohexyl group. Examples of the aryl group include a phenyl group and an α-naphthyl group. These alkyl groups or aryl groups may be substituted with various substituents such as a halogen atom, an alkyl group, an aralkyl group, an alkoxy group, a hydroxyl group, a cyano group and an aryl group. Examples of Z ₁ and Z ₂ include a non-metal atom group necessary for forming various heterocycles such as a pyridine ring, an isoquinoline ring, a pyrrole ring, an imidazole ring, a piperidine ring and a pyrrolidine ring.

Specific examples of the compound represented by formula <A> are shown below. The compound No. is commonly used in the examples.

[0021]

[Chemical 3]

[0022]

[Chemical 4]

[0023]

[Chemical 5]

The general formula used as the charge control agent of the present invention <
The compound represented by A> is obtained by, for example, adding an aqueous solution of boric acid and an amine to the following general formulas <F> and <G> (in the formula, R ₁ , R ₂ and R
₃ and R ₄ are easily obtained by adding and reacting a compound represented by the general formula <A>.

[0025]

[Chemical 6]

The compound represented by the general formula <A> added to the toner component is generally 0.1% with respect to 100 parts by weight of the resin.
-10 parts by weight, preferably 0.5-5 parts by weight.

The toner of the present invention has, in addition to the compound of the general formula <A>, adhesiveness, storability, fluidity and pulverizability,
Styrene resin, styrene-acrylic resin, styrene-
One or more known toner resins such as butadiene resin, epoxy resin, polyester resin, and paraffin wax may be mixed and used. Also, as an adhesive,
A large number of known dyes and pigments are used, and benzidine yellow, quinacdrine, copper phthalocyanine blue, copper phthalocyanine green and the like are particularly excellent as toners for color copying.

The toner of the present invention is usually mixed with a carrier to provide a two-component developer, but of course, it can be used as a one-component developer.

[0029]

The present invention will be described in detail below with reference to examples. "Parts" in the examples represent "parts by weight". The present invention is not limited to these examples.

Example 1 100 parts of styrene resin, 6 parts of carbon black and No. 1
2 parts of the compound represented by 1 were uniformly premixed with a ball mill to prepare a premix. Then, after heating, melting, kneading, cooling, coarse pulverization with a vibration mill and fine pulverization with a jet mill, a black toner having a particle size of 8 to 15 μm was obtained.
A developer was prepared by mixing 95 parts of an iron powder carrier with 5 parts of the obtained toner. The initial blow-off charge amount of this developer was −22.7 μC / g. When a toner image was formed on the commercially available selenium drum of this developer by a magnetic brush development method, a clear image without fog was obtained. With this developer, the copy quality did not deteriorate even after 10,000 continuous copies.

Example 2 100 parts of styrene-acrylic copolymer resin, yellow dye (C.
6 parts of I. Disperse Yellow 33) and 2 parts of the compound represented by No. 2 were treated in the same manner as in Example 1 to obtain a yellow toner. The developer prepared in the same manner as in Example 1 from the obtained yellow toner had an initial blow-off charge amount of −23.4 μC /
It was g. When this developer was copied in the same manner as in Example 1, a clear yellow image without fog was obtained. With this developer, the copy quality did not deteriorate even after 10,000 continuous copies.

Example 3 Styrene-n-butylmethacrylate copolymer resin 100
Part, 8 parts of red dye (CI Pigment Red 12) and N
2 parts of the compound represented by o.3 was treated in the same manner as in Example 1 to obtain a red toner. The developer initial blow-off charge amount adjusted in the same manner as in Example 1 from the obtained red toner was −
It was 28.2 μC / g. When this developer was copied in the same manner as in Example 1, a clear red image without fog was obtained. With this developer, the copy quality did not deteriorate even after 10,000 continuous copies.

Example 4 100 parts of polyester resin, 6 parts of blue dye (CI Pigment Blue 15) and 2 parts of the compound represented by No. 4 were treated in the same manner as in Example 1 to obtain a blue toner. The initial blow-off charge amount of the developer prepared from the obtained blue toner in the same manner as in Example 1 was −29.8 μC / g. When this developer was copied in the same manner as in Example 1, a clear blue image without fog was obtained. This developer is used for continuous copying 10,000
The copy quality did not deteriorate even after one sheet.

Example 5 Instead of the compound represented by No. 1 in Example 1, N was used.
A black toner was obtained in the same manner as in Example 1 except that the compound shown in Table 5 was used. The initial blow-off charge amount of the developer prepared by using the obtained black toner in the same manner as in Example 1 was −32.2 μC / g.

Example 6 Instead of the compound represented by No. 2 in Example 2, N was used.
A yellow toner was obtained in the same manner as in Example 2 except that the compound shown in o.6 was used. The initial blow-off charge amount of the developer prepared from the obtained yellow toner in the same manner as in Example 1 was −23.1 μC / g.

Example 7 Instead of the compound represented by No. 3 in Example 3, N was used.
A red toner was obtained in the same manner as in Example 3 except that the compound shown in o.7 was used. The initial blow-off charge amount of the developer prepared from the obtained red toner in the same manner as in Example 1 was −22.0 μC / g.

Example 8 In Example 4, instead of the compound represented by No. 4, N
A blue toner was obtained in the same manner as in Example 4 except that the compound shown in 0.8 was used. The initial blow-off charge amount of the developer prepared by using the obtained blue toner in the same manner as in Example 1 was −23.8 μC / g.

[0038]

The charge control agent used in the present invention is excellent in mechanical friction and impact stability, temperature and humidity stability and the like, and is white or substantially colorless (does not affect coloring of the colorant). Therefore, an electrophotographic toner (color electrophotographic toner) having a clear image and continuously usable is obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Ebisawa 2470 Handa, Shibukawa City, Gunma Japan Carlite Co., Ltd. R & D Center

Claims (1)

[Claims] 1. A toner for electrophotography, comprising a compound represented by formula <A> as a charge control agent. [Chemical 1] (In the formula, R ₁ and R ₄ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and R ₂ and R ₃ represent a substituted or unsubstituted aromatic ring (condensed ring). Is also included), M represents a trivalent metal, and X ^{n +} represents a cation.)