JPS5926020B2 - Electrophotographic toner composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic toner composition that hardly causes cake fern or blocking during triboelectric charging or storage in direct or indirect electrophotographic development.

As is well known, xerography is an electrophotographic method that applies static electricity, and the methods widely used commercially are the cascade method using glass beads as a carrier, the magnetic brush method using iron powder as a carrier, and the method using toner in the air. There are cloud methods that finely disperse the .

Both methods charge toner particles by friction and cause them to adhere to the electrostatic latent image by electrical attraction. Toner is a colored powder resin that becomes 100% positively or negatively charged when rubbed using methods such as the cascade method, magnetic brush method, and cloud development method. It must not cause blocking or cause cake fern during toner storage, which would impair the performance of the toner.

However, among the various resins conventionally used, polyester resins suffer from blocking during triboelectrification or storage.
Cake ferns were likely to occur, which often caused problems in use. There is an upper limit to the temperature at which the toner is fixed after the electrostatic latent image is transferred to paper, and if the temperature is too high, it not only wastes energy but also causes deterioration and burning of the paper. On the other hand, it is also necessary to use a polyester resin for toner having an appropriate softening point. The phenomenon of blocking or cake fern observed when using polyester resins is caused by the low melting point of the resin used. Increasing the softening point will slightly increase the melting point, but if you try to obtain a resin with a considerably high softening point, there will be a risk of gelation during production. The polyester resin for the toner used in the present invention is a special polyester resin manufactured in such a way that it does not raise its softening point and has a melting point higher than that of conventional polyester resins. The combination with pigments or dyes provides an improved toner that does not have the drawbacks mentioned above.

That is, the present invention consists of 1 to 20 parts by weight of a coloring agent and 80 to 99 parts by weight of a polyester resin, and the polyester resin (
A) dicarboxylic acids and (B) formula (R represents an alkylene group having 2 or 3 carbon atoms, X.
y is an integer and x+y is 2-7.

) and (C) 0.05 to 10 mol% of 1 to 2 phenolic hydroxyl groups and 1 alcoholic hydroxyl group or carboxyl group based on (8) The present invention relates to an electrophotographic toner composition characterized in that it is a resin co-condensed with a compound having the following.

Specific examples of the above compound (C) which is a raw material for producing the polyester resin used in the present invention include diphenolic acid, p-
Hydroxybenzoic acid, 2,4-dihydroxybenzoic acid,
p-hydroxyphenylacetic acid, p-hydroxybenzyl alcohol, phenolptaline, oxypropylene
2,2-bis(4-hydroxyphenyl)propane, oxyethylene-p-P7-bisphenol, oxypropylene-bis(4-hydroxyphenyl)thioether and oxybutylene-bis(4-hydroxyphenyl)
Examples include ketones.

The above compound (C) is present in the polyol component at 0.05 to 1
It is desirable to use it in a proportion of 0 mol%.

The dicarboxylic acids (A), which are raw materials for producing the polyester resin used in the present invention, have the following general formula (where A is 0
CH2+. , -CH=CH-, a phenylene group or a cyclohexylene group, and n is an integer of 1 to 4), or anhydrides thereof, such as fumaric acid, maleic acid, succinic acid, etc. Examples include malonic acid, cyclohexanedicarboxylic acid, glutaric acid, adipic acid, phthalic acid, isophthalic acid, elephthalic acid, maleic anhydride, and phthalic anhydride. In the present invention, the above polyol (B) has the etherified diphenol represented by the above general formula as a main component, but there is no problem in using a small amount (approximately 10 mol % or less) of a subcomponent. Examples of such subcomponents include ethylene glycol, propylene glycol, diethylene glycol,
Dipropylene glycol, neopentyl glycol, 1
・3-dihydroxybutane, 1,4-dihydroxypentane, hydrogenated bisphenol A1 glycerin, trimethylolpropane, etc., among which preferred are ethylene glycol, propylene glycol, neopentyl glycol, hydrogenated bisphenol A . In the production of the polyester resin used in the present invention, dicarboxylic acids (A
), polyol (B) and compound (C) are preferably carried out at about 200°C in an inert atmosphere.

At this time, catalysts or promoters commonly used in the production of polyester resins can be used to accelerate the reaction rate. When using an unsaturated dicarboxylic acid, it is desirable to add a small amount of a polymerization inhibitor such as hydroquinone or pyrogallol. In order to minimize contamination of the polyester product, it is desirable to carry out the reaction without adding an excessive amount of the esterification catalyst. The reaction is carried out under atmospheric pressure, but it can also be carried out under reduced pressure in order to hasten the reaction during the course of the polymerization reaction. The reaction ratio between dicarboxylic acids and polyols is such that the ratio of the number of hydroxyls in the polyol to the number of carboxyls in the dicarboxylic acid is 0.8 to 1.3, preferably 0.9 to 1.
．． The ratio is such that 2. The toner composition of the present invention may consist of 1 to 20 parts by weight of a colorant and 80 to 99 parts by weight of the above-mentioned specific polyester resin, but if necessary, small amounts of a charge control agent, a plasticizer, a filler, It may contain conventionally known toner resins and the like.

As the coloring agent, pigments or dyes may be used alone or in combination, and examples thereof include carbon black, aniline blue, phthalocyanine blue, rose bengal, and benzine yellow.

The colorant is 1 to 20% by weight of the toner composition, preferably 3% by weight of the toner composition.
It is used in a range of 10% by weight.

The toner composition of the present invention can be manufactured by any of the conventionally known liquid spraying methods or pulverization methods. In the case of the liquid spray method, the mixture of polyester resin and colorant is dissolved in a solvent such as carbon tetrachloride, the resulting liquid is spray-dried, and the fine particles are collected using electric dust. In this case, the polyester resin and the colorant are uniformly melt-mixed using a heated roll or the like, and the mixture is pulverized using a dinit grinder or the like to form a powder of 5 to 20 microns. Hereinafter, production examples of the resin used in the electrophotographic toner composition of the present invention, Examples of the toner composition of the present invention, etc. will be shown and further explained.

In addition, in the examples, the state of caking and blocking was evaluated by the operations shown below. That is, 100 y of powder with a constant particle size is placed at 30°C to 40°C and 30% to 100% relative humidity (if necessary, after leaving it for a week with a weight of about 1 kg on it, the powder is heated to a height of 1 m). The solids were dropped onto a 40 mesh sieve, the weight of the solids remaining on the sieve was measured, and this was taken as the caking index.

The softening point was measured by the ring and ball method according to JISK-2531, and the melting point was measured by the D. S. C (DifferentialS
eanning CalOri-Meter).

Production example 1 230.7 grams (1.987 mol) of fumaric acid, polyoxypropylene (2.2)-2,2-bis(
4-hydroxyphenyl)propane 651.2 grams (1
．． 85 mol), oxypropylene-2,2-bis(4-
Hydroxyphenyl)propane 16.3 grams (0.0
57 moles) and 0.45 grams of hydroquinone were placed in a 1 liter four-necked round bottom flask equipped with a thermometer, stirring bar, dehydration tube with a flowing down condenser, and nitrogen inlet tube, and the flask was supported in an electric heating mantonol.

Nitrogen gas was passed through the nitrogen inlet tube to inert the inside of the reaction vessel, and then the electric heating mantle was activated to melt the raw materials. After reacting for 7 hours, 7.5 g (0.08
mol) of glycerin was added and allowed to react for about 2 hours.

Thereafter, the pressure was gradually reduced to 100 mT1LHg, and the reaction was completed when the softening point reached 107°C. This polyester resin had an acid value of 24 W KOH/7 and a melting point of 61.5°C. VPO (Vap Or Pres
The molecular weight measured by the sureOsmOmeter method is 2
It was 650. Production Example 2 175 grams (1.507 mol) of fumaric acid, 528 grams (1.50 mol) of polyoxypropylene (2.2)-2,2-bis(4hydroxyphenyl)propane, 24 grams (1.50 mol) of phenolptaline 0.075 mol) and 0.3 grams of hydroquinone were placed in a 1 liter four-neck round bottom flask equipped with a thermometer, stirring bar, dehydration tube with a flowing down condenser, and nitrogen inlet tube, and the flask was supported in an electric heating mantle. .

Nitrogen gas was passed through the nitrogen inlet tube to inactivate the inside of the reaction vessel, and then an electric heating mantle was activated to melt the raw materials. While flowing nitrogen gas at a rate of 5 to 10 (100 to 150 m1/min) using a flowmeter (model KG-2, manufactured by Kusano Kagaku Kiki Seisakusho), the temperature was kept at 210°C and after 5 hours of reaction, the pressure was gradually reduced to about 10
Softening point was 99 after reacting at 0m71L/Hg for 100 minutes.
The reaction was terminated when the temperature reached ℃. This polyester resin had an acid value of 20 W KOH/7 and a melting point of 61.5°C.
The molecular weight measured by the VPO method was 2130. Example 1 90 parts by weight of the polyester resin obtained in Production Example 1 was blended with 10 parts by weight of carbon black, melted and kneaded in a hot roll, cooled and pulverized, passed through a 150-mesh sieve, and passed through a 200-mesh sieve.
After drying the powder that does not pass through the mesh sieve at room temperature for 2 days,
07 was placed in a 50 ml beaker and left in an atmosphere of 40° C. and 100% relative humidity for 2 days, and the caking index was measured to be 5 (5% by weight was caked).

Furthermore, the caking index was 10 when a load of 9207 was applied and left for one week.

Further, 90 parts by weight of this resin and 10 parts by weight of carbon black were melted and kneaded in a heated roll, cooled and pulverized, and then finely pulverized in a dinit pulverizer to produce a toner having a size of 5 to 20 microns. When this toner was used, a clear image without fogging or trailing could be obtained when negative electrostatic images were visualized using either the cascade method or the magnetic brush method. Example 2 90 parts by weight of the polyester resin obtained in Production Example 2 and 10 parts by weight of carbon black were melt-kneaded in a hot roll, cooled and pulverized, and the powder that passed through a 150 mesh sieve but did not pass through a 200 mesh sieve was prepared at room temperature. After drying for 2 days, 407
After being placed in a 0ml beaker and left in an atmosphere of 40°C and 100% relative humidity for 2 days, the caking index was measured to be 30 (30% by weight was caked).

Further, 90 parts by weight of this resin and 10 parts by weight of carbon black were melt-kneaded, cooled and pulverized, and then further pulverized using a dinit pulverizer to produce a toner having a size of 5 to 20 .mu.m. When this toner was used, clear images without fogging and trailing were obtained when negative electrostatic images were visualized by either the cascade method or the magnetic brush method. Comparative Example 1 209 grams (1.8 moles) of fumaric acid, 616 grams (1.75 moles) of polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane and 0.33 grams of hydroquinone. Using the same apparatus as in Production Example 1, the mixture was reacted at 210°C for 5 hours and then under reduced pressure for 110 minutes, and the reaction was terminated when the softening point reached 99°C.

This resin had an acid value of 21ηKOH/7 and a melting point of only 58°C.

The molecular weight measured by the VPO method was 2450. 10 parts by weight of carbon black was blended with 90 parts by weight of this resin,
After melting and kneading in a heated roll, cooling and pulverizing, the powder passed through a 150 mesh sieve but did not pass through a 200 mesh sieve. When the caking index was measured in the same manner as in Example 1, the result was 75.
(75% by weight caking).

Comparative Example 2 230.7 grams (1.987 moles) of fumaric acid, 678.5 grams (1.928 moles) of polyoxypropylene (2.2)-2,2-bis(4hydroxyphenyl)propane and 0 hydroquinone .45 grams were reacted for 7 hours using the same equipment as in Production Example 1, 7.5 grams (0.08 mol) of glycerin was added, and after about 2 hours of reaction, the reaction was terminated when the softening point reached 107°C. .

The acid value of this resin is 24rI9K0Y1/t, and the melting point is 57.
There was only ℃. The molecular weight measured by VPO method is 3000
It was hot.

Claims (1)

[Claims] 1. 1 to 20 parts by weight of colorant and 80 to 9 parts by weight of polyester resin.
The polyester resin consists of (A) dicarboxylic acids and (B) formula ▲ Numerical formula, chemical formula, table, etc. ▼ (R represents an alkylene group having 2 or 3 carbon atoms, x,
y is an integer and x+y is 2-7. ) and (C) 0.05 to 10 mol% of 1 to 2 phenolic hydroxyl groups and 1 alcoholic hydroxyl group or carboxyl group based on (B) An electrophotographic toner composition characterized by being a resin co-condensed with a compound having the following.