JPH02217868A - Positive chargeable toner - Google Patents

Abstract

PURPOSE:To obtain a high charge control effect with addition of a small amt. of a charge control agent by incorporating either of the inorg. acid salt or org. acid salt of specific 2-alkyl imidazole as the charge control agent. CONSTITUTION:The toner is so formed as to contain either of the inorg. acid salt or 2-alkyl imidazole of the 2-alkyl imidazole expressed by formula I as the charge control agent. In the formula, R2 denotes 11 to 17C alkyl group; R4 denotes a hydrogen atom or methyl group. The representative inorg. acid salt or org. acid salt of the 2-alkyl imidazole includes hydrochloriate, hydrobromate, etc., of C11Z, C17Z and C114MZ. The positive chargeable charge control agent which is suitable not only to the toner for black printing but also particularly to color printing, is white or pale in color, and yields the high charge control effect with the small amt. of addition is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a positively charged toner used for developing electrostatic latent images in electrophotography, electrostatic printing, or the like.

Conventional technology Generally, toner for developing electrostatic latent images is made of styrene resin,
After dispersing a coloring agent such as a dye or pigment and a charge control agent to impart positive or negative chargeability to a binder resin such as an epoxy resin or a polyester resin, fine particles with an average diameter of about 10 to 15 μm are dispersed. It is ground and adjusted.

In addition, special manufacturing methods include applying mechanochemical reactions to the surface of particles made of binder resin to attach pigments and charge control agents, or adding pigments and charge control agents to the monomers that are the raw materials for binder resin. After dispersing,
A method of producing spherical toner by suspension polymerization reaction is also known.

Conventionally, known charge control agents added to positively charged toners include nigrosine dyes, quaternary ammonium salts, and metal salts of higher fatty acids.

In addition, as an example of an imidazole compound being used in a toner for developing an electrostatic latent image, 2 is used as a negative charge control agent.
-Use of aminobenzimidazole (JP-A-61-21
No. 7055, No. 61-259265), a method of using vinyl imidazole in the outer shell of a capsule toner (Japanese Patent Application Laid-open No. 187350/1983), and a method of using vinyl imidazole as a hardening agent when an epoxy resin is used as a binder resin of the toner. A method of using an imidazole compound as
No. 94461, No. 62-242960).

Problems to be Solved by the Invention Among the conventionally known positive charge control agents, nigrosine dyes have poor sustainability of charge control effect and are black in color, so they are unsuitable for toners of colors other than black.

Furthermore, quaternary ammonium salts or metal salts of higher fatty acids are advantageous for color toners because they are white or light in color, but their charge control effect is inferior, so it is not possible to obtain a higher charge amount with a small amount of addition. Ta.

An object of the present invention is to provide a positively charged charge control agent that is white or light in color and is particularly suitable for color printing as well as toner for black printing, and that can provide a high charge control effect with a small amount added.

Means for Solving the Problems In view of the above circumstances, the present inventors conducted various tests and studies, and as a result, the following general formula having an alkyl group having 11 to 17 carbon atoms at the 2-position was used as a charge control agent. It has been found that when a salt of the imidazole compound represented by the above is used, excellent charge control performance is provided, and the present invention has been completed.

The salt of imidazole having an alkyl group at the 2-position which is suitable for carrying out the general formula of the present invention is 2-undecyl, imidazole (hereinafter referred to as C
0z), 2-heptadecyl imidazole (hereinafter referred to as C+qZ), and 2-undecyl-4-methylimidazole (hereinafter referred to as Cz4MZ) and an inorganic or organic acid in water or a solvent. The reaction product is precipitated by cooling, and the crystals are separated by filtration.The representative salt of 2-alkylimidazole is C+ + Z.
, CI? 2 and C++4MZ hydrochlorides, hydrobromides, sulfates, nitrates, phosphates, phosphites, laurates, palmitates, stearates, glycolates, lactates, oxalates, malonate, succinate, adipate, maleate, fumarate, tartrate,
Varanitrobenzoate, isophthalate, terephthalate, trimellitate, pyromellitate, etc., especially C,, Z hydrochloride (1,1), 95-103'c
), CI? Z sulfate (2:1) (m.

p, 80-108'c), CI? Z stearate [er, p, 80~b~154°C), C,? Z oxalate (2:l) (m
, p, 120-152'C), C, Z fumarate (1:1) (-0p, 140-148°C), C1f
fZ7? /L/acid (2:1) (*, p.

87-105”C), CI?Z) Limellitic acid salt (
Seagull, p, 168-177°c), C,? Z pyromellitate (m, p, 180~b 46'c), CzZ oxalate (m, p, 146~
150°C], C,, Z fumarate (m, p, 12
0-143°C], C1121 limellistate [layer, p
, 140-159'C), Cr + 4 M Z
'/, :L' hepta-acid (a+, p, 124-126
°C] and C, , 4MZ trimellitate (+, p,
125-b are preferred.

The 2-alkylimidazole salt in the positively charged toner of the present invention should be added in an amount of 0.1 to 10% by weight, preferably 0.5 to 5.0% by weight; If the amount of charge on the toner is too large, the amount of charge on the toner will change over time, making the charge control effect unstable. Further, in carrying out the present invention, a 2-alkylimidazole salt and a conventionally used positive charge control agent such as a nigrosine dye, a quaternary ammonium salt, or a higher fatty acid metal salt may be used in combination.

A typical binder resin suitable for carrying out the present invention is a copolymer resin of styrene and acrylic ester, and other resins such as polystyrene resin, polypropylene resin,
Polyethylene resins, polyamide resins, polyurethane resins, phenol resins, polyester resins, polycarbonate resins, etc., and mixtures of two or more of these can be used.

As the colorant, various known colorants can be used. For example, carbon black or nigrosine dye for black toner, rhodamine pigment or quinacridin pigment for red toner, copper phthalocyanine R pigment or anthracene derivative dye for blue toner, benzine yellow for yellow toner, etc. The use of colorants is possible.

Furthermore, the positively charged toner of the present invention can also be used as a magnetic toner by containing a magnetic material. The magnetic materials added to the magnetic toner include iron oxide, iron, cobalt, etc. such as magnetite, hematite, and ferrite.
Metals such as nickel or alloys containing these metals. These magnetic materials preferably have an average particle size of about 0.1 to 2 μm, and the amount contained in the toner is as follows:
40 to 150 per 100 parts by weight of binder resin component
Parts by weight are appropriate.

In carrying out the present invention, known additives that improve image characteristics may be blended in addition to the above-mentioned compounds. For example, a fluidizing agent such as colloidal silica, an abrasive such as strontium titanate and silicon carbide, a lubricant such as a metal stearate, and a conductivity imparting agent such as tin oxide can be added.

The positively charged toner of the present invention can be prepared by a known method. The most common method is to mix the 2-alkylimidazole salt, coloring agent, and other additives with the binder resin, and then thoroughly knead, coarsely crush, and finely grind using a heated roll, kneader, or extruder. This is a method of producing a toner having an average particle size of 10 to 15 μm by pulverizing and collecting particles with a particle size of 45 μm or less, preferably 4 to 20 μm.

Hereinafter, the present invention will be specifically explained with reference to Examples, Reference Examples, and Comparative Examples.

Reference Example I 12.3 g (0,040 mol) of Cl fu Z, 5.0 g (0,040 mol) of oxalic acid dihydrate, and 15 ethanol
0d was heated under reflux for about 10 minutes with stirring, then cooled with water, the precipitated crystals were collected by filtration, and further recrystallized from ethanol to give colorless flaky crystals with a melting point of 148-154°C. as CltZ・oxalic acid (1:1) salt 13.
7 g (0.0345 mol, yield 86%) was obtained.

Reference Example 2 17.8 g (0,080 mol) of C11Z, 9.3 g (0,080 mol) of fumaric acid, 200 i of water, and 10 d of ethanol were heated under reflux for about 10 minutes with stirring, and then cooled on ice. The precipitated crystals were collected by filtration and further recrystallized from a water-ethanol mixed solvent to give a melting point of 120 to 143°.
Cr + Z fumarate 25 as colorless microcrystals of C
．． 1 g (0.074 mol, yield 93%) was obtained.

Reference example 3 Trimellitic anhydride 11.5g (0,060 mol)
14.2 g of C, 4M Z (0,0
60 mol) was added little by little, and after the addition was complete, the temperature was kept at the same temperature for an additional 30 minutes with stirring.After the reaction was completed, it was cooled, and the precipitate was collected by filtration and washed with water to form a colorless powder with a melting point of 125-137'C. 22.3g of C++4MZ trimellitate
(0,050 mol, yield 83%) was obtained.

Various salts of imidazole compounds were obtained by the same method.

Examples 1 to 39 and Comparative Examples 1 to 3 Styrene-acrylic acid ester copolymer resin (manufactured by Fujikura Kasei ■: S-708F) was used as the binder resin, and carbon blank #40 (manufactured by Mitsubishi Chemical Industries, Ltd.) was used as the colorant. , neutral type) [hereinafter referred to as CB] or Lionol Blue FG7330 (manufactured by Toyo Ink ■, phthalocyanine-based blue pigment) [hereinafter referred to as F], and the imidazole salt shown in the reference example as a charge control agent. In addition, in the comparative example, a commercially available white quaternary ammonium salt type positively charged WF [control agent (manufactured by Orient Chemical Industry ■, BONTRON P-51)] was used, and these binder resins, colorants and Table 1 shows the charge control agent.
The mixture was blended according to the weight ratio shown in , tri-blended using a small mixer, and then blended using a twin-screw presser.
The mixture was kneaded at a temperature of ~160°C, extruded and then cooled to form a plate, which was coarsely crushed in a mortar, and then finely crushed using a tabletop crusher while cooling.
A sample was prepared by passing it through a sieve.

1 g of the sample and carrier (iron powder or ferrite)
25 g was placed in a polyethylene container (100 ml capacity), stirred and shaken on a rotating roll of a roll mill for 5 minutes or 30 minutes, and then the amount of charge was measured using a blow-off type charge amount measuring device.

The carrier is iron powder (DSP- manufactured by Dowa Iron Powder).
128B) or ferrite (F-15 made by Nippon Steel Powder)
0) was used.

In addition, the method for measuring the amount of charge is as follows:
00s+g, blow pressure 1 kg/c4. Measurement time 25
seconds, and the unit of measurement value is μC (10
−' coulombs).

The test results of Examples and Comparative Examples were as shown in Table 2.

Table 1. Sample composition and carrier type Table 2. Measurement result of charge amount (IC/g) Procedural amendment 1. Description of the case 1999 Patent Application No. 39143 2 Name of the invention Positively charged toner 3 Person making the amendment Relationship to the case: Patent applicant Effect of the invention According to the present invention, addition of a small amount of charge control agent Since a high charge control effect can be obtained and the charge control agent is white or light in color, it is suitable as an electrostatic photographic toner for color printing.

Patent applicant Shikoku Kasei Kogyo Co., Ltd. 4 Date of amendment order 5 Claims column and Detailed description of the invention column 6 of the specification subject to amendment 6 Contents of the amendment (1) Patent in the description The scope of claims is amended as shown in the attached sheet.

Correct "salt of imidazole compound" in the row to "inorganic acid salt or organic acid salt of imidazole compound".

(3) From page 4, line 6 to line 111 of page 4 of the specification, amend it to ``general formula inorganic acid salt or organic acid salt''.

(5) Line 1 of page 4 to page 5 of the specification, page 6, line 5
Line 6 to line 6 of the same page, line 11 of page 6 to line I2 of the same page
Correct line 1 and "salt of 2-alkylimidazole" to "inorganic or organic acid salt of 2-alkylimidazole".

that's all of [General formula Correct to.

(4) Line 8 from the bottom of No. 4 and line 7 from the bottom of No. 10 of the specification
``Salt of imidazole'' in the row is ``salt of imidazole''
(Paper) Claims after amendment (υ A positively charged toner bifurcated type % formula % characterized by including the U or F point left of 2-alkylimidazole represented by the following general formula as a charge control agent) 1. Indication of the case Patent Office No. 39143 of 1999 2. Name of the invention Positively charged toner 3. Person making the amendment Relationship to the case; Patent applicant 4. Date of notice of reasons for refusal Voluntary statement (1) Specification Correct "quinacrid" from line 7 to line 8 of page 7 to "quinacridone".

(2) “Benzine Yellow” on page 7, line 10 of the specification is “
Correct to "benzidine yellow".

Claims (1)

[Claims] (1) A positively charged toner comprising a 2-alkylimidazole salt represented by the following general formula as a charge control agent. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ {In the formula, R_2 is an alkyl group having 11 to 17 carbon atoms,
R_4 represents a hydrogen atom or a methyl group, and HA represents an inorganic or organic acid. }