JP3432774B2 - Toner production method - Google Patents

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. Description of the Related Art As factors relating to toner performance, there are charge amount control and dispersion degree control of additives such as wax. The dispersion state of various raw materials in the toner particles is substantially determined by the step of mixing the raw materials and the step of kneading the raw materials in the method for producing the toner by the pulverization method. However, for example, in the method using an extruder as disclosed in Japanese Patent No. 2677685, it is possible to sufficiently disperse the charge control agent, wax and the like required as a toner as the temperature of the composition rises due to the heat of kneading. I have a problem that I can't.

[0003]

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

[0004]

The summary of the present invention is as follows.
A toner having a step of melt-kneading a kneaded product obtained by previously melting and mixing a colorant with a binder resin and a composition containing a binder resin and a charge control agent using an open roll type continuous kneader having a heating and cooling function. In the melt kneading, the supply port is provided at a plurality of positions along the axial direction of the roll of the kneading machine, and the kneaded material, the binder resin, and the charge control agent are introduced into the kneading machine. Side roll end 0L (however, L
Is a roll length) to 0.9 L and is continuously supplied for melt kneading.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a toner according to the present invention, an open roll type continuous kneader having a heating and cooling function at the time of melt kneading is used, and raw materials are fed from a plurality of feeding ports. There is one big feature in. Thereby, the excellent effect that the degree of dispersion of the charge control agent and the like can be easily controlled and the toner having stable charging characteristics can be easily manufactured is exhibited.

The open roll type continuous kneader used in the present invention is an open roll type continuous kneader in which two rolls are arranged in parallel and close to each other, and raw materials are provided at a plurality of positions along the axial direction of the roll. The one provided with the supply port of is used.
Each roll can be heated or cooled by passing a heat medium. That is, one of the rolls is used as a heating roll, and the temperature is adjusted to a temperature near the melting temperature of the binder resin, and the other roll is used as a cooling roll and adjusted to a temperature equal to or lower than the melting temperature of the binder resin. The melting temperature (Tm) used was a Koka type flow tester (CFT-500, manufactured by Shimadzu Corporation), and the diameter of the pores of the die was 1 mm, the length was 1 mm, and the load was 20 kg / c.
m ² (196 N / cm ² ) and a temperature corresponding to ½ of the height from the outflow start point to the outflow end point when a 1 cm ³ sample is melted and flown out under the condition of a temperature rising rate of 6 ° C./min. To do.

The gap between the two rolls is preferably 0.1.
10 mm, more preferably 0.1 to 3 mm. Further, the structure, size, material, etc. of each roll are not particularly limited, and the roll surface may be smooth, corrugated, or uneven.

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 roll to the upper surface of the roll or between the two rolls. Therefore, it is preferable to carry out kneading.

The number of rotations of the roll at that time is such that the peripheral speed is 2-1
The rotation speed ratio of the two rolls is preferably 00 m / min (cooling roll rotation speed / heating roll rotation speed)
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.

The raw material is supplied to the open roll type continuous kneader by using, for example, a table feeder.

Before the raw materials are supplied, the raw materials may be premixed by using a mixing device. As a mixing device,
It is not particularly limited, and examples thereof include a high-speed stirring type mixing device such as a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), a super mixer (manufactured by Kawata), and a high speed mixer (manufactured by Fukae Kogyo).

Further, in the method for producing a toner of the present invention, when melt-kneading using the open roll type continuous kneader, a kneaded product obtained by previously melt-mixing a colorant with a binder resin like a master batch is used. There is one major feature in the point of use. By using such a kneaded product, the excellent effect that the colorant and the like can be sufficiently dispersed in the binder resin is exhibited.

The binder resin used in the present invention is not particularly limited, and known binder resins for black toner or color toner can be used. For example, JP-A-7-98518. Page 3, Column 4, Lines 37-6
Binder resins such as polyester resin and vinyl resin described in page 10, column 10 line, or binder resins obtained by polymerization reaction by mixing a release agent with a raw material monomer mixture may be used.

The content of the binder resin in the kneaded product is 50.
Is preferably 90 to 90% by weight, more preferably 60 to 80% by weight.

Further, it is 50 to 95% by weight, more preferably 80 to 95% by weight in the final composition containing the charge control agent, wax and the like. In the present invention, the binder resin is used by being contained in the kneaded product, and is also separately added to the open roll type continuous kneader.

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

The content of the colorant in the kneaded product is 10 to 10.
50 wt% is preferable, and 20-40 wt% is more preferable.

The content of the colorant in the final composition is preferably 2 to 15% by weight,
3 to 10% by weight is more preferable.

The method for producing the kneaded product is not particularly limited, and examples thereof include a heating roll mill, a batch kneader, and
A masterbatch may be performed at a temperature of Tm-20 ° C to Tm + 50 ° C with respect to the melting temperature (Tm) of the binder resin using a known manufacturing apparatus such as an axial extruder or an open roll type continuous kneader.

The kneaded product and the binder resin are supplied to the open roll type continuous kneader at a position of 0 L to 0.9 L, preferably 0 L, from the viewpoint of further improving the dispersity of the colorant.
It can be performed from one or more supply ports at a position of 0.5L, more preferably at a position of 0L to 0.3L.

The charge control agent is not particularly limited, and a known charge control agent for black toner or color toner can be used. As charge control agents for negatively charged toner, chromium / azo complex dyes; iron azo complex dyes; cobalt / azo complex dyes; chromium / zinc / aluminum / boron complexes or salicylic acid or its derivative compounds; naphtholic acid or its derivative compounds Chromium ・ Zinc ・ Aluminum ・ Boron Complex or Salt Compound; Chromium ・ Zinc ・ Aluminum ・ Boron Complex or Salt Compound of Benzyl Acid or its Derivatives; Long Chain Alkyl Carboxylate, Long Chain Alkyl Sulfonate, etc. Examples include agents. Further, as a charge control agent for positively charged toner, a nigrosine dye and its derivative, a triphenylmethane derivative, a quaternary ammonium salt,
Examples thereof include derivatives such as quaternary phosphonium salt, quaternary viridinium salt, guanidine salt and amidine salt.

The charge control agent is adjusted to a desired degree of dispersion,
Positions of 0L to 0.9L, preferably 0L to 0.
It is supplied from one or more supply ports at a position of 8L, more preferably at a position of 0.2L to 0.7L. When a plurality of charge control agents are used, the supply position can be changed according to the degree of dispersion for each purpose. The effect of the charge control agent increases as the degree of dispersion is increased, but the effect decreases as the degree of dispersion is further increased. Therefore, it is preferable to control the average particle size (dispersed particle size of the charge control agent) so that the charge control agent to be used has an optimum degree of dispersion, and the optimum average particle size in the kneaded material of the charge control agent is 0.1-3 μm, preferably 0.1-2 μm
Is desirable. In order to highly disperse the charge control agent, when using an open roll type continuous kneader, it is preferable to remove the heat of mixing during kneading and increase the viscosity of the kneaded product to generate a stronger dispersing force. . The average particle size is
Formula (I):

[0024]

[Equation 1]

(A: major axis of particle [μm], b: minor axis of particle [μm], n: number of measured particles, major axis and minor axis were obtained by observing with a transmission electron microscope). You can ask.

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 an electric charge. And from the viewpoint of transparency as a toner,
It is desirable that the content is 15% by weight or less, preferably 10% by weight or less.

The composition used in the present invention may further contain wax and the like. Examples of waxes include natural waxes and synthetic waxes, silicone-based waxes, higher fatty acids, polyolefin-based waxes, and low molecular weight polymers. Among these, natural wax is preferably used,
Specific examples include carnauba wax, rice wax, candelilla wax, and beeswax.

The wax is 0 depending on the desired degree of dispersion.
It is preferable to supply from one or more supply ports at a position of L to 0.9L, preferably a position of 0L to 0.8L, and more preferably a position of 0L to 0.6L. When a plurality of waxes are used, the supply position can be changed according to the degree of dispersion for each purpose. The wax in the toner is incompatible with the binder resin and exists in a separated state. Therefore, if the average particle size of the wax (dispersed particle size of the wax) is too large, the wax appears on the toner surface, and If the toner adheres to the photoconductor or the time elapses, the charge amount decreases and stable development cannot be performed. On the other hand, if the average particle size of the wax is too small, the speed of bleeding out of the wax at the time of fixing becomes slow and the wax does not function as an offset preventing agent. Therefore, the average particle diameter of the wax obtained by the above formula (1) is the weight average particle diameter (D) of the toner.
On the other hand, it is preferably 0.1 to 0.3 Dm, and specifically, 0.5 to 3 m is desirable. The weight average particle diameter (D) of the toner is the Coulter counter (Beckman Coulter, Inc., Aperture 1).
00 μm).

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 exerting a good offset preventing effect. From the perspective of suppression
It is desired to be 20% by weight or less, preferably 15% by weight or less.

The final kneaded product obtained by the above melt kneading step can be continuously taken out from the open roll type continuous kneader. The final kneaded product thus obtained is cooled, then solidified, pulverized, and then further processed in a known step such as classification, whereby a toner can be produced.

Examples of the cooling device used for cooling include a cooling belt.

Examples of the crushing device used for crushing include a jet mill, a collision plate type mill, and a rotary mechanical mill.

Examples of the classifying device used for classification include an air classifier, an inertial classifier and a sieve classifier.

The toner thus obtained is excellent in dispersibility of the colorant, and further dispersibility of the charge control 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 is not filmed on the photosensitive member in the printing machine and the image is stable after printing. An excellent effect is exhibited.

[0036]

Example Preparation of Kneaded Material Polyester resin [glass transition point (Tg) = 60 ° C., melting temperature 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)] 70 parts by weight Copper phthalocyanine pigment (CI Pigment Blue 15: 3) 30 parts by weight A raw material having the above composition was melt-mixed at 100 ° C. using a heating roll mill to prepare a kneaded product. The glass transition point is a differential scanning calorimeter (manufactured by Seiko Denshi Kogyo Co., Ltd., trade name: DSC210), the temperature is raised to 200 ° C., the temperature is left at that temperature for 3 minutes, and then the temperature decreasing rate is 10 ° C. When a sample cooled to room temperature at a heating rate of 10 ° C./min was heated at a heating rate of 10 ° C./min and the thermal history was measured, an extension line of the baseline below the glass transition temperature and a peak portion from the rising portion of the peak The temperature at the intersection with the tangent line showing the maximum slope up to.

[0037] Prescription   Kneaded material 17 parts by weight   Polyester resin (same as that used to prepare the kneaded product) 88 parts by weight   Charge control agent     Benzyl borate complex (trade name: LR-147, manufactured by Nippon Carlit Co., Ltd.)                                                           1.5 parts by weight     Chromium salicylate complex (trade name: E-84, manufactured by Orient Chemical Industry Co., Ltd.)                                                           1.5 parts by weight

Example 1 An open-roll type continuous kneader (Mitsui Mining Co., Ltd.) was used to mix 1.5 kg of the above raw material with a table feeder.
Manufactured, trade name: Kneedex). Table 1 shows the supply position and supply amount of each raw material at that time. When the feed positions of the raw materials are the same, the raw materials were put into a Henschel mixer (effective volume: 10 L), which is a mixing device, and mixed at a blade rotation speed of 2500 rpm for 1 minute to obtain a product. Different mixtures were 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 0.6.
[M], and operating conditions are: high rotation side roll (front roll) rotation speed 75 rotations / minute, low rotation side roll (rear roll) rotation speed 50 rotations / minute, roll gap 0.1 mm, inside roll The heating and cooling medium temperatures are 100 ° C. on the raw material charging side of the high rotation roll and 100 ° C. on the kneading material discharging side of the high rotation roll, and 30 ° C. on the raw material charging side of the low rotation roller and 3 ° C.
At 0 ° C., the feed rate of the raw material mixture was 10 kg / hour and the average residence time was about 2 minutes.

The obtained toner kneaded product was cooled with a cooling belt and then roughly crushed with a mill having a screen of φ2 [mm]. Next, this coarsely pulverized product was pulverized by a collision plate type jet mill, and further, coarse powder and fine powder were cut by a cyclone type air classifier to obtain a cyan toner having a weight average particle diameter of 9 μm. The weight average particle diameter of the toner was measured with a Coulter counter. Further, to 100 parts by weight of the obtained toner, 1.0 part by weight of hydrophobic silica (“Aerosil R-972”, manufactured by Nippon Aerosil Co., Ltd.) was externally added to obtain a developer. The obtained developer was used as a transmission electron microscope (250
Observation of the particle size of the charge control agent at 0 times)
The particles had an average particle size of 0.3 μm. Furthermore, diameter 15m
Using a commercially available non-magnetic one-component type full-color electrophotographic recording apparatus having a m developing roller, a printing durability test of 10,000 sheets was performed, and a stable image could be obtained.

Example 2 Using the formulation, melt kneading and the like were carried out under the same conditions as in Example 1 except that the feed position and feed amount of each raw material were as shown in Table 1. A particle size of 9 μm) was obtained. The developer thus obtained was observed with a transmission electron microscope (2500 times) for the particle size of the charge control agent.
It was dispersed in 5 μm. Further, stable images could be obtained even in the printing durability test of 10,000 sheets.

Example 3 Using the formulation, melt kneading and the like were carried out under the same conditions as in Example 1 except that the feed position and feed amount of each raw material were as shown in Table 1. A particle size of 9 μm) was obtained. The obtained developer was observed with a transmission electron microscope (2500 times) for the particle size of the charge control agent, and the average particle size was 1 μm.
It was dispersed in m. Further, stable images could be obtained even in the printing durability test of 10,000 sheets.

Example 4 A melt kneading process was carried out under the same conditions as in Example 1 except that the prescription was used and the feed positions and feed rates of the respective raw materials were as shown in Table 1. A particle size of 9 μm) was obtained. The developer thus obtained was observed with a transmission electron microscope (2500 times) for the particle size of the charge control agent.
It was dispersed in 5 μm. Further, stable images could be obtained even in the printing durability test of 10,000 sheets.

Comparative Example 1 A developer (weight average) was prepared under the same conditions as in Example 1 except that the prescription was used and the feed position and feed amount of each raw material were as shown in Table 1. A particle size of 9 μm) was obtained. The obtained developer was observed with a transmission electron microscope (2500 times) for the particle size of the charge control agent, and the average particle size was 3.
Dispersed in 5 μm, in a printing durability test of 10,000 sheets,
Due to poor dispersion of the charge control agent, fogging, lowering of transfer rate and uneven development occurred, and stable images could not be obtained.

[0045] Prescription   Kneaded material 17 parts by weight   Polyester resin (same as that used to prepare the kneaded product) 88 parts by weight   Charge control agent     Benzyl borate complex 1.5 parts by weight     Chromium salicylate complex 1.5 parts by weight   Carnauba wax 10 parts by weight

Example 5 Using the prescription, melt kneading and the like were carried out under the same conditions as in Example 1 except that the feed position and feed amount of each raw material were as shown in Table 1. A particle size of 9 μm) was obtained. The developer thus obtained was observed with a transmission electron microscope (2500 times) for the particle size of the charge control agent.
It was dispersed in 5 μm. Further, a stable image could be obtained even in a printing durability test of 10,000 sheets, and there was no filming on the photoreceptor, which was good.

COMPARATIVE EXAMPLE 2 Melt-kneading and the like were carried out under the same conditions as in Example 1 except that the feed position and feed amount of each raw material were set as shown in Table 1 by using the formulation, and the developer (weight average) was used. A particle size of 9 μm) was obtained. The obtained developer was observed with a transmission electron microscope (2500 times) for the particle size of the charge control agent, and the average particle size was 3.
Dispersed in 5 μm, in a printing durability test of 10,000 sheets,
Due to poor dispersion of the charge control agent, fogging, lowering of transfer rate and uneven development occurred, and stable images could not be obtained.

[0048]

[Table 1]

[0049]

The toner obtained by using the present invention is excellent in the dispersion of the colorant, and the dispersion degree of the charge control agent and the wax is appropriately controlled. It is preferably used in printing methods and magnetic recording methods.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-133660 (JP, A) JP-A-3-149567 (JP, A) JP-A-9-319145 (JP, A) JP-A-5- 249738 (JP, A) JP 10-171159 (JP, A) JP 6-308766 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (2)

(57) [Claims] 1. A kneaded product obtained by previously melt-mixing a colorant with a binder resin and a composition containing a binder resin and a charge control agent are melt-kneaded using an open roll type continuous kneader having a heating and cooling function. In the method for producing a toner having a step of, in the melt kneading, supply ports are provided at a plurality of positions along the axial direction of the roll of the kneading machine, and the kneaded product, the binder resin and the charge control agent are provided. A method for producing a toner, which comprises continuously feeding and kneading from a roll end portion 0L (where L represents roll length) to 0.9L on the inlet side of the kneading machine. 2. The manufacturing method according to claim 1, wherein the wax is further supplied from one or more supply ports.