JP2000075543A - Production of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a producing method of a toner having excellent dispersion of a coloring agent, and to provide a producing method of a toner in which the dispersibility of charge controlling agent and wax is controlled. SOLUTION: This producing method includes a process to melt and knead a compsn. containing a binder resin and a coloring agent by using an open roll type continuous kneading machine having heating and cooling functions. In the melting and kneading process, supply ports are disposed at plural positions along the axial direction of the roll of the kneading machine, and 6 to 70 wt.% of the binder resin to be compounded is continuously supplied at the position of 0 L to 0.5 L (wherein L is the roll length) in the entrance side of the kneading machine, while 50 to 100 wt.% of the coloring agent is supplied at the position of 0L to 0.5L for melting and kneading.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner used in electrophotography, electrostatic printing, magnetic recording, and the like.

[0002]

2. Related Background Art Factors relating to the performance of a color toner include coloring power and transparency. Although the coloring power and the transparency are influenced by the amount of the colorant, it is also greatly influenced by the degree of dispersion of the colorant in the color toner particles. The dispersion state of the various raw materials in the color toner particles is substantially determined by the step of mixing the raw materials and the step of kneading in the production method of the color toner by the pulverization method.

In order to solve such a problem, Japanese Patent Laid-Open Publication No.
Japanese Patent No. 1154 discloses a technique of dispersing a water-insoluble dye and / or pigment in a binder resin by a flushing method. JP-A-6-11895 discloses that the step of melt-kneading is divided into two steps, a raw material mixture is granulated in a first kneading step, and an additive such as a binder resin is added and diluted in a second kneading step. A mixing technique is disclosed.
However, these attempts not only require a plurality of special steps, but also have the problem that the steps are very many and complicated.

Further, in a method using an extruder as disclosed in Japanese Patent No. 2677685, the dispersion of a colorant, a charge control agent, a wax and the like required as a color toner is increased as the temperature of the composition rises due to heat of kneading. There is a problem that it cannot be performed sufficiently.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner excellent in dispersing a colorant, a charge control agent, and a method for producing a toner in which the degree of dispersion of wax is controlled. .

[0006]

That is, the gist of the present invention is as follows.
A method for producing a toner, comprising: a step of melt-kneading a composition containing a binder resin and a colorant using an open-roll continuous kneader having a heating and cooling function. Supply ports are provided at a plurality of positions along the axial direction of the roll, and 6 to 70
% By weight of the end of the roll at the entrance side of the kneader (0 L
L indicates the length of the roll). The colorant is continuously supplied from a position of 0.5 to 0.5 L, and a colorant of 50 to 1 at a position of 0 to 0.5 L.
The present invention relates to a method for producing a toner, in which 00% by weight is supplied to perform melt kneading.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a toner of the present invention, an open-roll continuous kneader having a heating and cooling function is used when a composition containing a binder resin and a colorant is melt-kneaded. Another major feature is that raw materials are supplied from a plurality of supply ports. As a result, the degree of dispersion of the colorant and the like can be easily controlled, and the raw materials of the composition can be kneaded at a time, so that the time required for the production is significantly reduced, and a toner excellent in the dispersion of the colorant can be easily obtained. An excellent effect of being able to be manufactured is exhibited.

The open roll type continuous kneader used in the present invention comprises an open roll type continuous kneader in which two rolls are arranged in parallel and close to each other, and feeds raw materials to a plurality of positions along the axial direction of the rolls. The one provided with the supply port is used.
Each roll can be heated or cooled by passing a heat medium. That is, one is a heating roll and the temperature is adjusted to a temperature near the melting temperature of the binder resin, and the other roll is a cooling roll and adjusted to a temperature lower than the melting temperature of the binder resin. The melting temperature (Tm) was measured using a height type flow tester (CFT-500, manufactured by Shimadzu Corporation), the diameter of the pores of the die was 1 mm, the length was 1 mm, and the load was 20 kg / c.
The temperature is set to a temperature corresponding to の of the height from the outflow start point to the outflow end point when a 1 cm ³ sample is melted out under the conditions of m ² G and a heating rate of 6 ° C./min.

The gap between the two rolls is preferably 0.1
10 to 10 mm, and more preferably 0.1 to 3 mm. There is no particular limitation on the structure, size, material, and the like of each roll, and the roll surface may be smooth, corrugated, uneven, or the like.

[0010] While rotating the two rolls in the opposite direction, the raw material is supplied from the supply ports provided at a plurality of positions along the axial direction of the rolls, or the upper surface of the roll or between the two rolls. Thus, it is preferable to perform kneading.

In this case, the number of rotations of the roll is set at a peripheral speed of 2-1.
It is preferably 00 m / min, and the rotation speed ratio of the two rolls (the rotation speed of the cooling roll / the rotation speed of the heating roll)
Is preferably 1/10 to 9/10.

A desired kneading force can be obtained by appropriately adjusting the kneading temperature and the number of roll rotations.

In order to supply the raw materials to the open roll type continuous kneader, for example, a table feeder is used.

Before the raw materials are supplied, the raw materials may be premixed using a mixing device. As a mixing device,
There is no particular limitation, and a high-speed stirring type mixing device such as a Henschel mixer (manufactured by Mitsui Mining), a super mixer (manufactured by Kawata), a high-speed mixer (manufactured by Fukae Kogyo), a Reedige mixer (manufactured by Matsubo) and the like can be mentioned.

The binder resin used in the present invention is not particularly limited, and a known binder resin for a black toner or a color toner can be used. For example, JP-A-7-98518 Page 3, column 4, line 37 to sixth
A binder resin such as a polyester resin or a vinyl resin described in column 10, line 10 of the page, or a binder resin obtained by a polymerization reaction obtained by mixing a release agent with a raw material monomer mixture may be used.

In the case of melt-kneading with the open roll type continuous kneading machine, in order to sufficiently disperse the colorant and the like in the binder resin, the kneading is performed through supply ports provided at a plurality of positions along the axial direction of the roll. It is preferable to supply a resin for adhesion. From the viewpoint of obtaining a sufficient residence time and improving the degree of dispersion of the colorant and the like, from the position of 0 L to 0.5 L, it is at least 6% by weight, preferably at least 10% by weight of the binder resin to be blended, It supplies up to 70% by weight, preferably up to 50% by weight. In particular, it is more preferable to supply 6 to 30% by weight of the binder resin to be blended from the position of 0 L to 0.3 L.
By adjusting the amount of the binder resin at the site, the colorant concentration in the kneaded material is increased, the viscosity of the kneaded material is increased, and a higher kneading force is generated, thereby improving the degree of dispersion. it can.

The colorant is not particularly limited, and a known colorant for a black toner or a color toner can be used. The colorant includes a black colorant, a yellow pigment, a red or red pigment, a blue pigment, a green pigment, and the like. These colorants may be used alone or in combination of two or more.

In order to sufficiently disperse the colorant, it is preferable to supply the colorant from one or more supply ports along the axial direction of the roll, and from the viewpoint of improving the degree of dispersion,
Supplying 50% by weight or more, preferably 80% by weight or more and 100% by weight or less of the coloring agent to be blended from one or more positions of 0L to 0.5L, preferably 0L to 0.3L. Thus, the colorant can be highly dispersed.

The content of the coloring agent in the composition supplied from the position of 0 to 0.5 L is intended to increase the viscosity of the composition, obtain a stronger kneading force, and improve the degree of dispersion. The content is desirably 3% by weight or more, preferably 5% by weight or more, and is desirably 50% by weight or less, preferably 30% by weight or less from the viewpoint that a large amount of colorant can be satisfactorily kneaded in the binder resin. .

The composition used in the present invention may further contain a charge controlling agent, wax and the like.

The charge control agent is not particularly limited, and a known charge control agent for black toner or color toner can be used. Chromium-azo complex dyes; iron azo complex dyes;
Cobalt / azo complex dyes; chromium / zinc / aluminum / boron complexes or salt compounds of salicylic acid or derivatives thereof; chromium / naphthalic acid or derivatives thereof
Zinc / aluminum / boron complex or salt compound; chromium / zinc / aluminum / boron complex or salt compound of benzylic acid or a derivative thereof; surfactants such as long-chain alkyl carboxylate, long-chain alkyl sulfonate, etc. Is mentioned. Examples of the charge control agent for the positively charged toner include derivatives such as nigrosine dyes and derivatives thereof, triphenylmethane derivatives, quaternary ammonium salts, quaternary phosphonium salts, quaternary viridinium salts, guanidine salts, and amidine salts. Can be

The charge control agent is used in accordance with a desired degree of dispersion.
It is preferable to supply from one or more supply ports at a position of 0 L to 0.9 L. When a plurality of charge control agents are used, their supply positions can be changed according to the desired degree of dispersion. The effect of the charge control agent increases as the degree of dispersion increases, but the effect decreases as the degree of dispersion increases further. Therefore, it is preferable to control the degree of dispersion so that the charge control agent used has an optimum degree of dispersion. The optimal dispersion particle size of the charge control agent in the kneaded product is preferably from 0.1 to 3 μm, and more preferably from 0.1 to 2 μm.

The content of the charge control agent in the final composition is preferably 0.1% by weight or more, and more preferably 0.5% by weight or more, from the viewpoint of imparting electric charge. And from the viewpoint of transparency as a toner,
It is desirably 15% by weight or less, preferably 10% by weight or less.

Examples of the wax include natural waxes and synthetic waxes, silicones, higher fatty acids, polyolefins, and low molecular weight polymers. Among these,
Natural wax is preferably used, and specific examples thereof include carnauba wax, rice wax, candelilla wax, and beeswax.

The wax is used in an amount of 0 according to the desired degree of dispersion.
It is preferable to supply from one or more supply ports at positions L to 0.9L. When a plurality of waxes are used, their supply positions can be changed in accordance with the desired degree of dispersion. Since the wax in the toner is present in a separated state without being compatible with the binder resin, if the dispersed particle diameter of the wax is too large, the wax appears on the toner surface and adheres to the photoconductor in the developing machine, As time elapses, the charge amount decreases, and stable development cannot be performed. On the other hand, if the dispersed particle diameter of the wax is too small, the speed at which the wax bleeds out at the time of fixing becomes slow, and the wax does not work as an offset preventing agent. Therefore, equation (1):

[0026]

(Equation 1)

The average particle diameter of the wax obtained in the above is 0.1 to 0.3 Dμ with respect to the weight average particle diameter (D) of the toner.
m, specifically, 0.5 to 3 μm
It is desirable that

The content of the wax in the final composition is preferably 1% by weight or more, and more preferably 3% by weight or more, from the viewpoint of exhibiting a good offset prevention effect. In terms of suppression,
It is desirably 20% by weight or less, preferably 15% by weight or less.

The kneaded material obtained by the above-described melt kneading process can be continuously taken out from an open roll type continuous kneader. The obtained kneaded product is cooled, then solidified, pulverized, and classified to be further processed in a known process, thereby producing a toner.

The cooling device used for cooling includes, for example, a cooling belt.

Examples of the pulverizing apparatus used for pulverization include a jet mill, a collision plate type mill, a rotary mechanical mill and the like.

The classifier used for classification includes, for example, an air classifier, an inertial classifier, a sieve classifier and the like.

The toner thus obtained is excellent in dispersibility of a colorant, and further, dispersibility of a charge controlling agent, wax and the like.

When such a toner is used in a printing method such as an electrophotographic method, an electrostatic printing method, and a magnetic recording method, the toner has no filming on a photosensitive member in a printing machine, and an image is stable after printing. Excellent effects are exhibited.

[0035]

EXAMPLES Formulation Polyester resin [Glass transition point (Tg) = 60 ° C., softening point Tm = 110 ° C. (acid component: terephthalic acid 40 parts by weight, fumaric acid 60 parts by weight; alcohol component: polyoxyethylene (2. 0) -2,2-bis (4-hydroxyphenyl) propane 100 parts by weight)] 100 parts by weight Copper phthalocyanine pigment (CI Pigment Blue 15: 3) 3 parts by weight

Examples 1-3 An open roll continuous kneader (Mitsui Mining Co., Ltd.) was prepared by mixing 1.5 kg of the above-mentioned raw material with a table feeder.
(Trade name: Kneedex). Table 1 shows the supply positions and supply amounts of the respective raw materials at that time. When the feed positions of the respective raw materials are the same, each raw material is charged into a Henschel mixer (effective volume: 10 L) as a mixing device, and the mixture is obtained by mixing at a blade rotation speed of 2500 rpm for 1 minute. Was used.

The open roll type continuous kneader used at this time had a roll outer diameter of 0.14 [m] and an effective roll length of 0.8.
[M], and the operating conditions were as follows: high rotation side roll (front roll) rotation speed 75 rotations / minute, low rotation side roll (rear roll) rotation speed 50 rotations / minute, roll gap 0.0001 m,
The heating and cooling medium temperature in the roll is 100 ° C. on the material input side of the high-speed roll and 100 ° C. on the kneaded material discharge side, 30 ° C. on the material input side of the low-rotation roll and 30 ° C. on the kneaded material discharge side, and supply of the raw material mixture. The speed was 5 kg / h and the average residence time was about 5 minutes.

After cooling the obtained kneaded toner with a cooling belt, it was crushed with a mill having a screen of φ2 [mm]. Next, the crushed material was pulverized by a collision plate type jet mill, and coarse and fine powders were further cut by a cyclone type air classifier to obtain a cyan toner having a weight average particle diameter of 9 μm. The average particle size of the toner was measured with a Coulter counter. Further, 2 parts by weight of colloidal silica was externally added to 100 parts by weight of the obtained toner to obtain a developer.

An image output test was performed using the obtained developers, and the coloring power and transmittance of each toner used in each developer were confirmed. The image-drawing test was performed using Tektronix Phaser 550 manufactured by Kyushu Matsushita Electric Co., Ltd. First, regarding the image density, O
Using an HP sheet, the amount of toner on the sheet is 0.5 m
g / cm ² , a solid image is prepared, fixed at a temperature of 160 ° C., the image density is adjusted to about 1.3, and the coloring power and transmission of the image obtained using the HAZE value are adjusted. The sex was evaluated. Table 1 shows the results. The HAZE value is represented by the following equation. The better the dispersibility of the colorant, the lower the diffuse transmittance, and accordingly, the smaller the HAZE value. The HAZE value of the color toner used is usually about 22% or less. Further, images obtained after continuous copying of 10,000 sheets were also examined in the same manner (hereinafter, referred to as “images”).
As a result, a stable image was obtained in each case.

[0040]

(Equation 2)

Comparative Example 1 A toner such as melt-kneading was manufactured under the same conditions as in Example 1 except that the supply position and supply amount of each raw material were changed as shown in Table 1 using the formulation. 9 μm in diameter). When the pigment dispersion in this toner was measured by a HAZE meter, a good image could not be obtained with HAZE = 28%. In a 10,000-sheet printing test, a stable image could not be obtained.

Formulation: polyester resin [glass transition point (Tg) = 60 ° C., softening point Tm = 110 ° C. (acid component: terephthalic acid 40 parts by weight, fumaric acid 60 parts by weight; alcohol component: polyoxyethylene (2.0 ) -2,2-bis (4-hydroxyphenyl) propane 100 parts by weight)] 100 parts by weight Copper phthalocyanine pigment (CI Pigment Blue (CI Pigment Blue) 15: 3) 3 parts by weight Charge control Agent (boron benzylate complex) 3 parts by weight

Example 4 A toner (weight-average particle size: 9 μm) was obtained by performing melt-kneading and the like under the same conditions as in Example 1 except that the supply position and supply amount of each raw material in the formulation were as shown in Table 1. Was. When the obtained toner was observed for the particle size of the charge control agent with a transmission electron microscope (2500 times), it could be dispersed to an average particle size of about 0.3 μm. The pigment dispersion in this toner is H
When measured with an AZE meter, a good image was obtained with HAZE = 18%. Further, a stable image could be obtained even in a printing durability test of 10,000 sheets.

Example 5 A toner (weight average particle size: 9 μm) was obtained by performing melt kneading and the like under the same conditions as in Example 1 except that 100% of the charge control agent was supplied from the position of 0.5 L in the formulation. . Observation of the particle diameter of the charge controlling agent of the obtained toner with a transmission electron microscope (2500 times) revealed that the average particle diameter was about 0.5 μm. The pigment dispersion in this toner is HAZ
When measured with an E-meter, a good image was obtained with HAZE = 19%. Further, a stable image could be obtained even in a printing durability test of 10,000 sheets.

Comparative Example 2 Melting and kneading were performed under the same conditions as in Comparative Example 1 except that 100% of the charge control agent was supplied from the position of 0.5 L in the formulation to obtain a toner (weight average particle diameter 9 μm). Was. Observation of the particle size of the charge controlling agent of the obtained toner with a transmission electron microscope (2500 times) revealed that the average particle size was about 3.5 μm. The pigment dispersion in this toner is HA
When measured with a ZE meter, a good image could not be obtained with HAZE = 26%. 10,000 more
Also in the printing durability test of sheets, fog, a decrease in transfer rate, and uneven development occurred due to poor dispersion of the charge control agent.

Formulation: polyester resin [glass transition point (Tg) = 60 ° C., softening point Tm = 110 ° C. (acid component: terephthalic acid 40 parts by weight, fumaric acid 60 parts by weight; alcohol component: polyoxyethylene (2.0 ) -2,2-bis (4-hydroxyphenyl) propane 100 parts by weight)] 100 parts by weight Copper phthalocyanine pigment (CI Pigment Blue) 15: 3) 3 parts by weight Carnauba wax 10 parts by weight

Example 6 A toner (weight average particle size: 9 μm) was obtained by performing melt kneading and the like under the same conditions as in Example 1 except that the supply position and supply amount of each raw material in the formulation were as shown in Table 1. Was. Observation of the wax particle size of the obtained toner with a transmission electron microscope (2500 times) showed that the average particle size was about 1.5 μm. When the pigment dispersion of this toner was measured with a HAZE meter, it showed a good dispersion of HAZE = 22%, and a good image could be obtained.

Example 7 In the formula, 100% of the wax was 0.5% from the inlet side.
Melt kneading and the like were performed under the same conditions as in Example 1 except that the toner was supplied from the L position, to obtain a toner (weight average particle diameter 9 μm). Observation of the wax particle size of the obtained toner with a transmission electron microscope (2500 times) showed that the average particle size was about 1.5 μm. The pigment dispersion in this toner is H
When measured with an AZE meter, HAZE was 17%, showing good dispersion, and a good image could be obtained. Further, a stable image could be obtained even in a printing durability test of 10,000 sheets, and the film was good without filming on the photosensitive member.

Comparative Example 3 In the formulation, 100% of the wax was 0.5% from the inlet side.
Melt kneading and the like were performed under the same conditions as in Comparative Example 1 except that the toner was supplied from the L position, to obtain a toner (weight average particle size: 9 μm). Observation of the wax dispersion particle size of the obtained toner with a transmission electron microscope (2500 times) showed that the average particle size was 0.5 μm.
m could be dispersed. When the pigment dispersion in this toner was measured with a HAZE meter, HAZE = 2
A good dispersion of 5% could not be obtained. Therefore, a target image density could not be obtained.

[0050]

[Table 1]

From the results shown in Table 1, the toners obtained in Examples 1 to 7 all have a lower HAZE value than the toners obtained in Comparative Examples 1 to 3, and therefore, all of the toners have the same colorant. It can be seen that the dispersion is excellent.

The toners obtained in Examples 4 and 5 are:
It can be seen that the charge control agent has a better degree of dispersion than the toner obtained in Comparative Example 2.

Further, it can be seen that the toners obtained in Examples 6 and 7 are more suitable in the degree of dispersion of the wax than the toner obtained in Comparative Example 3.

[0054]

EFFECTS OF THE INVENTION The toner obtained by using the present invention is excellent in dispersion of a colorant and in which the degree of dispersion of a charge control agent and wax is appropriately controlled. It is well used in printing and magnetic recording.

Claims (3)

[Claims] 1. A method for producing a toner, comprising: a step of melt-kneading a composition containing a binder resin and a colorant using an open-roll continuous kneader having a heating and cooling function. At this time, supply ports are provided at a plurality of positions along the axial direction of the roll of the kneading machine, and 6 to 70% by weight of the binder resin to be compounded is added to the roll end 0L on the entrance side of the kneading machine (where L is (Length of the roll is shown.) The melt is kneaded by continuously supplying from the position of ~ 0.5L, and supplying 50 to 100% by weight of the colorant at the position of 0L to 0.5L.
Manufacturing method of toner. 2. The method according to claim 1, wherein the charge control agent is further supplied from one or more supply ports. 3. The method according to claim 1, wherein the wax is further supplied from one or more supply ports.