JPH05249747A - Positively chargeable toner for electrophotography - Google Patents

Abstract

PURPOSE:To provide a positively chargeable toner not contg. a metal such as Cr. CONSTITUTION:This positively chargeable toner is obtd. by using a compd. not contg. a metal represented by the formula, wherein X is an electron withdrawing group and each of R1 and R2 is H, halogen, alkyl, cycloalkyl, aralkyl, aryl, alkoxy or hydroxyl.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positively chargeable electrophotographic toner containing a specific compound.

[0002]

2. Description of the Related Art In an electrophotographic image forming process, an electrostatic latent image is formed on an inorganic photoreceptor such as selenium, selenium alloy, cadmium sulfide, or amorphous silicon, or an organic photoreceptor using a charge generating agent and a charge transporting agent. After being formed, this is developed with toner, transferred onto paper or a plastic film, and fixed to obtain a visible image.

The photosensitive member has a positive charging property and a negative charging property depending on its configuration. When the printed portion is left as an electrostatic latent image by exposure, it is developed with a toner of opposite sign charging, while the printed portion is discharged. When reversal development is carried out, the development is carried out with a toner having the same sign. A toner is composed of a binder resin, a colorant and other additives, but is generally a charge control agent in order to impart desirable triboelectrification characteristics (charging speed, charging level, charging stability, etc.), temporal stability and environmental stability Is used. The characteristics of the toner are greatly affected by this charge control agent.

Positive developing toner is used when developing with negative sign charging toner using negative charging photoreceptor and reverse developing using positive charging photoreceptor, and in this case positive charging toner is used. A sex charge control agent is used.

Further, in the case of a color toner, a light color, preferably colorless charge control agent which does not affect the hue is required. Examples of these light-colored or colorless charge control agents include quaternary ammonium salts described in JP-A-57-119364, JP-A-58-9154 and JP-A-58-98742. There is a compound.

However, these charge control agents exponentially decay depending on storage conditions even if the toner has a high charging property in the initial stage of developer adjustment, and the decay is remarkably large especially when the temperature is high and the humidity is high. There is a drawback, and the parahalophenylcarboxylic acid described in JP-A-58-186752 has a drawback of poor thermal stability.
In addition, the charge control agents described above are mostly reverse-charged toners, which have a low charging effect. Alternatively, there are drawbacks such as poor dispersibility and poor stability of the compound, and none of them have satisfactory performance as a charge control agent.

[0007]

DISCLOSURE OF THE INVENTION The present invention has high stability as a colorless compound, good dispersibility in a binder resin, no deterioration at the time of toner production, and no friction by various environmental conditions. The present invention provides a toner having good charging characteristics and always providing a high quality image in a stable manner.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have found a colorless stable compound which has good dispersibility with a binder resin and can impart good charging characteristics to a toner. The present invention has led to the invention of excellent toners.

That is, the present invention is represented by the following general formula (1)

[0010]

[Chemical 1]

(Wherein X represents an electron-withdrawing group, R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an aryl group,
Represents an alkoxy group or a hydroxyl group. And a positively chargeable electrophotographic toner containing a compound represented by the formula (1).

The present invention basically comprises a binder resin, a colorant and a compound represented by the general formula (1) according to the present invention. As a method for producing the toner of the present invention, a mixture of these is used. Method of obtaining by kneading, cooling, coarsely pulverizing, finely pulverizing, and classifying after melting the binder resin by a heating and mixing device, dissolving these mixtures in a solvent, atomizing by spraying, drying, and classifying And a method in which the colorant or the compound represented by the general formula (1) is dispersed in the suspended monomer particles to obtain it by a polymerization method.

As the binder resin, polystyrene,
Styrene-methacrylic acid ester copolymer, styrene-
Propylene copolymer, styrene-butadiene copolymer,
Acrylic resins, styrene-maleic acid copolymers, olefin resins, polyesters, epoxy resins, polyurethane resins, polyvinyl butyral, etc. can be used alone or in combination.

As a colorant, carbon black is generally used for black toners, and the following colorants can be used for color toners. Examples of yellow colorants include azo organic pigments such as CI Pigment Yellow 1, CI Pigment Yellow 5, CI Pigment Yellow 12, and CI Pigment Yellow 17, and inorganic pigments such as ocher or CI Solvent Yellow 2, CI Solvent Yellow 6, CI. Oil-soluble dyes such as Solvent Yellow 14 and CI Solvent Yellow 19,

Examples of magenta colorants include azo pigments such as CI Pigment Red 57 and CI Pigment Red 57: 1, xanthene pigments such as CI Pigment Violet 1 and CI Pigment Red 81, and CI Pigment Red 8
7, CI bat red 1, CI pigment violet 38 and other thioindigo pigments or CI solvent red 1
9, oil-soluble dyes such as CI Solvent Red 49, CI Solvent Red 52, etc.,

Examples of cyan colorants include triphenylmethane pigments such as CI Pigment Blue 1, phthalocyanine pigments such as CI Pigment Blue 15 and CI Pigment Blue 17, or CI Solvent Blue 25, CI Solvent Blue 40, CI Solvent Blue 70 and the like. Known colorants such as oil-soluble dyes can be used.

The electron withdrawing group of the compound according to the present invention which can be used as a charge control agent is a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a halogen-substituted alkyl group such as trifluoromethyl group, a halogen-substituted aryl group. , Cyano group, formyl group, carboxyl group, carbamoyl group, N-substituted carbamoyl group, alkoxycarbonyl group, acyloxy group, acyl group, arylcarbonyl group, nitro group, sulfonic acid group, alkylsulfo group, substituted sulfonyl group, sulfamoyl group , N-substituted sulfamoyl groups, substituted sulfinyl groups and the like.

Specific examples of the compound according to the present invention which can be used as the charge control agent include the following.

Compound No (1)

[Chemical 2]

Compound No. (2)

[Chemical 3]

Compound No (3)

[Chemical 4]

Compound No. (4)

[Chemical 5]

Compound No. (5)

[Chemical 6]

Compound No. (6)

[Chemical 7]

Compound No. (7)

[Chemical 8]

Compound No. (8)

[Chemical 9]

Compound No. (9)

[Chemical 10]

Compound No. (10)

[Chemical 11]

Compound No. (11)

[Chemical 12]

Compound No. (12)

[Chemical 13]

Compound No. (13)

[Chemical 14]

Compound No (14)

[Chemical 15]

Compound No. (15)

[Chemical 16]

Compound No. (16)

[Chemical 17]

Compound No. (17)

[Chemical 18]

Compound No (18)

[Chemical 19]

Compound No (19)

[Chemical 20]

Compound No (20)

[Chemical 21]

Further, the toner may be used as an additive in the toner.
For the purpose of carrier protection, toner fluidity improvement, thermal / electrical / physical property adjustment, resistance adjustment, softening point adjustment, and fixability improvement, hydrophobic silica, metal soap, fluorine-based surfactant, Dioctyl phthalate, wax, tin oxide, conductive zinc oxide and the like are used as necessary.

When the toner of the present invention is used as a two-component developer, as a carrier, fine glass beads, iron powder, ferrite powder, a binder type carrier of resin particles in which magnetic particles are dispersed, or a polyester resin on the surface, Fluorine resin,
A resin coated carrier coated with an acrylic resin, a silicone resin or the like is used. Further, the toner of the present invention exhibits excellent performance even when used as a one-component toner.

[0041]

EXAMPLES The present invention will be specifically described below with reference to examples. Parts in the examples represent parts by weight.

Example 1 4-fluorocinnamic acid (Compound No (1)) (1 part), carbon black (5 parts) and styrene-ethylhexyl methacrylate copolymer (94 parts) were kneaded by a heating mixer, cooled, and then roughened by a hammer mill. Crushed. It was finely pulverized with a jet mill and then classified to obtain a black toner of 10 to 12 μm.
This toner was mixed with an iron powder carrier at a weight ratio of 4: 100, and when shaken, the toner was positively charged, and the charge amount was +30 μc when measured with a blow-off powder charge amount measuring device.
/ G. When this toner was used to produce an image with a modified commercial copying machine, a clear image was obtained even at the initial stage and after copying 10,000 sheets.

Example 2 1 part of 4-chlorocinnamic acid (Compound No (2)), 5 parts of carbon black, and 94 parts of styrene-ethylhexyl methacrylate copolymer were kneaded by a heating mixer, and after cooling, coarsely kneaded with a hammer mill. Crushed. It was finely pulverized with a jet mill and then classified to obtain a black toner of 10 to 12 μm.
This toner was mixed with an iron powder carrier in a weight ratio of 4: 100, and when shaken, the toner was positively charged, and the charge amount measured by a blow-off powder charge amount measuring device was +25 μc.
/ G. When this toner was used to produce an image on a modified commercial copying machine, a clear image could be obtained even at the initial stage and after copying 10,000 sheets.

Example 3 1 part of 4-fluorocinnamic acid (Compound No. (1)) and Spilon Blue which is a copper phthalocyanine oil-soluble dye
5 parts of 2BNH (product of Hodogaya Chemical Co., Ltd.) and 94 parts of styrene-butyl methacrylate copolymer were kneaded by a heating mixer, cooled, and coarsely crushed by a hammer mill. Finely pulverized with a jet mill and then classified to 10-1
A 2 μm blue toner was obtained. This toner was mixed with an iron powder carrier in a weight ratio of 4: 100 and shaken to positively charge the toner, and the charge amount measured by a blow-off powder charge amount measuring device was +33 μc / g. When this toner was used to produce an image on a modified commercial copying machine, a clear image could be obtained even at the initial stage and after copying 10,000 sheets.

Example 4 4-Fluoro-3-methylcinnamic acid (Compound No (1
3)) 1 part, carbon black 5 parts, and styrene-ethylhexyl methacrylate copolymer 94 parts were kneaded by a heating mixer, cooled, and then coarsely crushed by a hammer mill. Finely pulverized with a jet mill and then classified to 10-12 μm
To obtain a black toner. When this toner was mixed with a silicon coating carrier at a weight ratio of 4: 100 and shaken, the toner was positively charged, and the charge amount measured by a blow-off powder charge amount measuring device was +28 μc / g. When this toner was used to produce an image on a modified commercial copying machine, a clear image could be obtained even at the initial stage and after copying 10,000 sheets.

Examples 5 to 10 The results shown in Table 1 were obtained in the same manner as in Example 1 except that the compounds shown in Table 1 were used instead of the 4-fluorocinnamic acid of Example 1.

[0047]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kayoko Watanabe 45 Miyukigaoka, Tsukuba City, Ibaraki Prefecture Hodogaya Chemical Industry Co., Ltd. Tsukuba Research Institute

Claims (1)

[Claims] 1. The following general formula: (In the formula, X represents an electron-withdrawing group, and R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, an alkoxy group or a hydroxyl group.) A positively chargeable electrophotographic toner comprising a compound represented by: