JPH0895290A - Production of electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE: To reduce the volatile component resulting from the toner production process by supplying a liq. during kneading. CONSTITUTION: At least a resin and a colorant are mixed, kneaded, crushed and classified to produce an electrostatic charge image developing toner. In this case, a liq. is supplied during the kneading. Namely, a liq., especially an inert liq. exhibiting volatility in a continuous extruder, is supplied into the extruder. A liq. thermally stable during the kneading can be used, and industrial water, distilled water, etc., are exemplified. Meanwhile, the liq. is appropriately added to the molten layer wherein the kneaded material is melted in the extruder, and the liq. is supplied behind a first kneading part when the kneaded material is transformed from solid to melt in the first kneading part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of producing an electrostatic charge image developing toner used in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art A developer used in an electronic copying machine or the like is once attached to an image carrier such as a photoconductor on which an electrostatic charge image is formed in the developing process, and then is transferred to the photoconductor in the transferring process. After being transferred from the sheet to the transfer sheet, it is fixed on the copy sheet surface in the fixing step. At that time, as a developer for developing the electrostatic charge image formed on the latent image holding surface, a two-component developer consisting of a carrier and a toner and a one-component image agent not requiring a carrier (magnetic toner, non-magnetic Magnetic toner)
It has been known.

The toner contained in the developer is mainly composed of a binder resin in the case of a non-magnetic toner, and a binder resin and a magnetic powder in the case of a magnetic toner, and a colorant, a charge control agent, a release agent, etc. Dispersedly contained. Styrene-acrylic resins and polyester resins are often used as the binder resin, and raw material monomers, polymerization initiators, synthesis solvents, and the like used in the synthesis process thereof are often left. In addition, amines may be contained in the charge control agent as impurities.

[0004]

At present, as a fixing method of a copying machine or a printer, a heat fixing method such as a heat roll fixing method, an oven fixing method, a flash fixing method or the like is used to fix the binder resin in the toner in a molten state by heat. Law is common. The temperature is, for example, about 100 to 200 ° C. in the case of the hot roll fixing method. At that time, if the above-mentioned raw material monomers, solvent, impurities, etc. remain in the toner, they are volatilized, and a peculiar odor is generated from the electrophotographic apparatus. In recent years, due to downsizing of copiers and printers, operations in the office and the like have become more frequent in the vicinity of people, and the problem of such odor has come to the forefront.

Further, uniformizing the dispersion of the additives such as the charge control agent, the colorant, and the release agent in the toner makes the chargeability of the toner particles uniform, which in turn improves the copy image quality and durability. As a result, the toner production method is improved and environmental dependency is improved. For example, JP-A-4-313762 proposes a toner manufacturing method in which water is added together with a toner material and melt-kneaded. However, in recent years, continuous extruders are often used as a kneader used in the kneading step in consideration of toner productivity, and even if the manufacturing method of the above-mentioned patent publication is adopted in such an extruder, the amount of additives The dispersion was not sufficient, and the toner performance was not satisfactory.

Therefore, it is a first object of the present invention to provide a toner manufacturing method capable of reducing volatile components derived from the toner manufacturing process. A second object is to provide a method for producing a toner having a uniform composition with good dispersibility of additives in the toner. A third object is to provide a toner that has little environmental dependence and is excellent in storage stability. A fourth object is to provide a toner having stable image characteristics, image quality, charging characteristics and the like even when continuously copied, and having excellent durability.

[0007]

As a result of various studies made by the present inventors, the present inventors have found that the toner performance can be improved by adding a liquid during the toner kneading step, and arrived at the present invention. That is, the gist of the present invention is to supply a liquid during the kneading step in a method for producing an electrostatic charge image developing toner in which at least a resin and a colorant are mixed and mixed, and then kneaded, pulverized, and classified. And a method for producing a toner for developing an electrostatic image.

The present invention will be described in detail below. As the resin used in the present invention, known resins suitable for toner can be used. For example, polystyrene, polychlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer. Polymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene- Phenyl acrylate copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-
Ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic ester copolymer, etc. Styrene resin (styrene or homopolymer or copolymer containing styrene substitute), vinyl chloride resin, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin (including saturated and unsaturated), polyethylene resin , Polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer resin,
There are xylene resin, polyvinyl butyral resin, polycarbonate resin, and the like, and preferable resins for use in the present invention include styrene resin, polyester resin, epoxy resin, and the like. Further, the above resins are not limited to be used alone, but may be used in combination of two or more kinds.

The flow softening temperature (Tm) of the resin is 8
The temperature is preferably about 0 to 150 ° C, more preferably about 90 to 140 ° C. If the temperature is lower than 80 ° C, the fixing temperature on the paper is low and good, but hot offset is likely to occur, and the toner is easily crushed inside the developing tank, resulting in a spent phenomenon in which the toner adheres to the carrier surface and the doctor blade. However, there is a problem in that the charging characteristics are deteriorated and the durability performance of the developer is deteriorated. On the other hand, if it is higher than 150 ° C., the fixing temperature on the fixing paper is high, and the toner pulverizability is poor.

The glass transition temperature of the resin is preferably about 45 ° C. or higher, and when the temperature is lower than 45 ° C., the toner is hard to agglomerate or stick when left at a high temperature of 40 ° C. for a long time, resulting in poor storage stability. There is a problem in use such that toner agglomerates are likely to be generated in the external addition step, and moreover, they are easily attached to the screen, side wall, etc. of the sieving device to generate agglomerates.

The resin may be produced by known solution polymerization, suspension polymerization, bulk polymerization, emulsion polymerization or the like, and the low molecular weight polymer and the high molecular weight polymer may be polymerized differently as necessary. Further, from the viewpoint of the odor of the toner, the total amount of light-boiling components such as the amount of residual monomers and residual solvent in the resin is 2,000 ppm or less, preferably 1,000 ppm or less.

Each test method of the resin used in the present specification will be described below. [Flow softening temperature (Tm)] In a flow tester (CFT-500 manufactured by Shimadzu Corporation), 1 g of a sample was used, a die of nozzle 1 mm × 10 mm, a load of 30 kg, a preheating time of 50 ° C. for 5 minutes, and a heating rate of 3 ° C. The measurement is performed under the condition of / min, and the temperature at the midpoint of the distance from the start to the end of the flow is defined as the softening temperature.

[Glass transition temperature (Tg)] A transition (inflection) start part of a curve measured by a differential thermal analyzer (DTA-40 manufactured by Shimadzu Corporation) at a heating rate of 10 ° C./min. A tangent line is drawn to the glass transition temperature. As the colorant used in the present invention, known pigments and dyes may be used. For example, carbon black, titanium oxide, zinc white, alumina white, calcium carbonate, ultramarine blue, navy blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine dye, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallyl methane type Colorants such as dyes, anthraquinone dyes, monoazo and diazo dyes and pigments can be used alone or in combination of two or more. The content of colorant is
The amount is sufficient to color the toner so that a visible image can be formed by development. For example, 1 to 20 parts by weight, preferably 3 to 15 parts by weight is suitable for 100 parts by weight of the resin.

Further, known positively-charged or negatively-charged charge control agents may be used alone or in combination in the toner, and the amount thereof may be selected according to the desired charge amount ratio, for example, resin 100. About 0.05 to 10 parts by weight is preferable with respect to parts by weight. Examples of positively chargeable charge control agents include nigrosine dyes, quaternary ammonium salt compounds,
Triphenylmethane compounds, imidazole compounds,
Examples include polyamine resins. As the negative charge control agent, a metal-containing azo dye such as Cr, Co, Al or Fe,
Examples thereof include metal salicylate compounds, metal alkylsalicylate compounds, and carlix arene compounds.

Further, if necessary, other internal additives may be used alone or in combination as an auxiliary agent, and examples thereof include low molecular weight olefin polymers of known release agents, fillers and the like. First, an example of the toner production flow of the present invention will be described with reference to FIG. 1, but the present invention is not limited to the following description as long as the gist thereof is not exceeded.

As a toner internal additive, at least a resin and a colorant are weighed in predetermined amounts, blended, and mixed. As an example of the mixing device, a double cone mixer, a V-type mixer,
Drum type mixers, super mixers, Henschel mixers, Nauta mixers, etc. are available. Next, in the kneading step, a batch type (for example, a pressure kneader, a Banbury mixer, etc.) or a continuous type kneader is used. In recent years, a single-screw or twin-screw extruder is mainly used because of its superiority such as continuous production. And, for example, KTK type twin-screw extruder manufactured by Kobe Steel,
Toshiba Machine Co., Ltd. TEM twin screw extruder, KCK twin screw extruder, Ikegai Iron Works PCM twin screw extruder, Kuriyama Seisakusho twin screw extruder, Bus Co. kneader, etc. Is good.

After kneading, the toner is rolled by a two-roll mill or the like, and undergoes a cooling step of cooling by air cooling, water cooling or the like. Then
In the crushing step, coarse crushing is performed by a crusher, hammer mill, feather mill, etc., and fine crushing is performed by a jet mill, a high-speed rotor rotary mill, etc., and generally, the toner particles are pulverized stepwise.

After crushing, an inertia classification type elbow jet,
The toner is classified with a centrifugal force classification type microplex, a DS separator, etc. to obtain a toner having an average particle diameter of 3 to 15 μm. The toner coarse powder generated in the classification step may be returned to the crushing step, and the fine powder generated may be returned to the blending step of the toner raw materials for reuse.

Further, when the toner is externally added, the classified toner and various known external additives are blended in a predetermined amount and stirred by a high speed stirrer such as a Henschel mixer or a super mixer which gives a shearing force to the powder.・ It is good to mix. At this time, since heat is generated inside the external additive machine and aggregates are easily generated, it is preferable to adjust the temperature by means such as cooling the periphery of the container part of the external additive machine with water. The internal material temperature is preferably below the control temperature, which is about 10 ° C. lower than the glass transition temperature of the resin.

As the external additive, various known inorganic or organic external additives can be used. In particular, in order to improve the fluidity of the toner and suppress the cohesiveness, titania, silica, alumina, zinc oxide, and oxidation are used. Inorganic fine powder such as magnesium is suitable. The mixing amount of the external additive varies depending on the external additive to be used and the average particle size, particle size distribution, etc. of the toner particles, but an amount that provides a desired toner fluidity is good, for example, the toner particles 1
0.05 to 10 parts by weight, more preferably 0.
1 to 8 parts by weight is preferred. If the mixing amount is less than 0.01 parts by weight, the fluidity improving effect is small and the storage stability at high temperature is poor, and if the mixing amount is more than 10 parts by weight, filming occurs on the photoconductor due to a part of the external additive liberated. Undesirably, or it accumulates inside the developing tank and causes problems such as deterioration of the charging function of the developer. Further, from the viewpoint of stability in a high-humidity environment, the external additive is more preferably hydrophobized with a treatment agent such as a known silane coupling in the case of the inorganic fine powder, and in consideration of chargeability In that case, dimethyldichlorosilane, monooctyltrichlorosilane, hexamethyldisilazane, silicone oil, or the like may be used as the negative-charge imparting treatment agent, and aminosilane or the like may be used as the positive-charge imparting treatment agent. .

In addition, as a toner external additive, for the purpose of resistance adjustment, abrasives, etc., known magnetites other than those for improving fluidity, farite, conductive titanium, antimony oxide, tin oxide, cerium oxide, hydrotalcites, etc. An appropriate amount of fine powder such as a compound, acrylic beads, silicone beads, and polyethylene beads may be mixed, and the mixing amount is preferably 0.005 to 10 parts by weight with respect to 100 parts by weight of the toner.

The obtained toner is a one-component developer which does not use a carrier (a magnetic one-component toner containing a magnetic substance such as magnetite or a non-magnetic one-component toner not containing a magnetic substance), or an iron powder, It can be used as a two-component developer mixed with a magnetic carrier such as ferrite, magnetite, or a magnetic resin carrier.

The toner production method of the present invention is characterized in that a liquid, particularly an inert liquid which is volatile in the continuous extruder, is supplied in the middle of the continuous extruder. As long as it has thermal stability,
For example, water such as industrial water and distilled water is preferable. The position of the extruder for adding the liquid is preferably in the molten layer portion where the kneaded material is in a molten state. For example, when the kneaded material changes from the solid state to the molten state in the first kneading portion, the first kneading portion is used. The liquid may be supplied later. When the liquid is supplied to the solid state, which is the position before the molten state, the temperature of the kneaded product gradually rises and the liquid is vaporized, and bubbles are formed in the kneaded product, coloring agent to the resin, charge control agent, etc. Is not preferable because the dispersion of is not improved. The amount of the liquid supplied is preferably about 0.01 to 5 parts by weight, more preferably 0.03 to 4 parts by weight, per 100 parts by weight of the extruded amount of the kneaded product. When the liquid supply amount is small, the desired effect is difficult to obtain, and when the liquid supply amount is large, the kneaded product is difficult to disperse properly, which is not preferable. The liquid may be added and supplied in the form of water drops by using a commercially available supply device such as a plunger pump and a gear pump.

It is preferable to remove the supplied liquid as vapor from the kneaded product by providing a plurality of vent ports at the rear of the position where the liquid is supplied in the molten state of the kneaded product and degassing it.
Vacuum suction of all or part of the vent port with a vacuum pump or the like improves the filling state of the kneaded product and improves the efficiency of removing volatile components, which is preferable. Further, the screw configuration between the vent ports is preferably a screw configuration having a high sealing efficiency for blocking gas, because volatile components in the toner are more easily removed.

The kneaded product can improve the dispersion of the toner additive by changing from a solid state or a semi-molten state to a molten state by self-heating in the kneading section in the front part of the extruder, and the kneading section in the rear part. Installation, screw shape
The wettability with the colorant or the like can be improved by changing the constitution and setting the kneaded product to a high temperature state in which it is sufficiently melted.
The kneading conditions can be appropriately selected by adjusting and controlling the screw configuration, screw rotation speed, extrusion rate, barrel temperature, vent number, etc., depending on the materials used and the desired toner performance.

The number of axes of the continuous extruder is preferably one or two. The number of screw threads may be appropriately selected from 2, 3, or 4 threads in consideration of dispersibility, productivity, kneading temperature, and the like. The size of the continuous extruder is preferably such that the screw feed / kneading part of the kneaded product, the liquid supply part, and a plurality of vent ports can be sufficiently arranged, and the barrel inner diameter is D
(Mm) and the length from the material supply section to the barrel tip is L (mm), L / D is 30 or more, and further 35
The above is preferable.

[0027]

By using the method for producing a toner for developing an electrostatic charge image of the present invention, a toner having a small odor at the time of toner fixing can be obtained, and a toner having a good dispersibility such as a coloring agent in a resin and a charge control agent. The image quality is stable even during continuous use, and it provides a great industrial benefit by providing a toner having excellent durability performance.

[0028]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the following examples, "parts" simply means "parts by weight".

[0029]

[Table 1] Styrene / n-butyl acrylate copolymer resin 100 parts (Tm = 130 ° C, Tg = 60 ° C) Colorant carbon black MA-100S (Mitsubishi Kasei Co., Ltd.) 6 parts Charge control agent Bontron P-51 (Orient Chemical Industry Co., Ltd.) 2 parts ・ Low molecular weight polypropylene (number average molecular weight of vapor pressure osmometry = 7,500) 2 parts ・ Low molecular weight polyethylene PE130 (Hoechst KK) 1 part

The main raw materials of (1) were mixed and mixed with a Nauta mixer, and a continuous extruder (PCM-30, manufactured by Ikegai Co., Ltd., L /
D = 41), kneaded, cooled, coarsely pulverized, jet mill pulverized, and air-classified to obtain a black toner having an average particle size of 9 μm. To 100 parts by weight of this black toner, 0.35 part of silica powder (R972 of Nippon Aerosil Co., Ltd.) and fine powder of magnetite (EPT-1000 of Toda Kogyo Co., Ltd.) were used.
Two parts were externally added with a Henschel mixer to obtain an externally added toner. 4 parts of this toner and 96 parts of Cu-Zu-ferrite carrier (average particle size = 100 μm) whose surface was coated with a resin containing methyl silicone were stirred with a V-type mixer,
A developer was prepared by mixing.

This developer is used as a starting developer, externally added toner is used as replenishing toner, and a photoconductor of negatively chargeable organic photo-semiconductor is mounted.
A live-action photo test was performed. The odor determination at the time of toner hot roll fixing was performed by the headspace method, which correlates well with the sensory test described in Japanese Patent Application No. 5-197430 and Japanese Patent Application No. 5-197431. The headspace method encloses the toner in a closed container, heats it up to the temperature at the time of heat fixing of a copying machine, etc., and quickly converts the gas in the container into a gas chromatograph while the container is filled with volatile components. It is injected and the amount of volatile components is measured.
Further, the measurement of the headspace method will be described in detail.

● Measuring method 1. Sample Collection 1 g sample is collected in a headspace vial. The sample is weighed to 0.01 g (necessary to calculate the area per unit weight). Seal the vial with a septum using a dedicated crimper.

2. Heating of sample The sample is put in a thermostat of 130 ° C in a standing state and heated for 30 minutes.

3. Chromatographic separation state setting Silicon oil SE-30 so that the weight ratio becomes 15%
Carrier coated with (chromosorf w:
AWCS) packed in a column having an inner diameter of 3 mm and a length of 3 m is used as a separation column. The separation column was attached to a gas chromatograph, and He was used as a carrier in 50 ml.
Run at a rate of / min. The temperature of the separation column is set to 60 ° C, 10 ° C /
Measurement is performed while raising the temperature to 200 ° C. in minutes. After reaching 200 ° C, hold for 5 minutes.

4. Introduction of sample Take out the sample bottle from the thermostat and immediately inject 1 ml with a gas tight syringe.

5. Introduction of reference sample Using a hexane solution of styrene adjusted to 1000 ppm as a reference sample, 2 μl is injected.

[Calculation] When 2 μl of a 1000 ppm styrene solution is injected, 2 μg of styrene is injected, which is 0.43 μl in volume conversion at room temperature and normal pressure. Therefore, the amount of volatile components can be calculated by the following formula.

[0038]

[Equation 1]

[0039] Equipment

[0040]

[Table 2] Gas chromatograph Shimadzu GC-9APF heating furnace Shimadzu GC-4BPTF sample bottle Shimadzu vial (content capacity 20 ml) Septum Same as above Vial septum (heat-resistant temperature 150 ° C) Gas tight syringe DYNATECH PRECISION SAMPLING Corp. Gas tight syringe (internal volume 2 ml)

<Example 1> ○ Kneading conditions A schematic diagram of a continuous extruder IKE-30 made by Ikegai Co., Ltd. is shown in FIG.
4 to 4, and the kneading conditions were as follows.

[0042]

[Table 3] -L (length) / D (inner diameter) = 41-Number of screw shafts: 2 shafts (rotating in the same direction) -Number of screw threads: 2-Kneaded material extrusion rate: 15 kg / Hr (material supply port 4 Supplied by gravity using a screw feeder) -Vent vacuum suction: The vent port 7 was sucked by a vacuum pump. (Vent ports 5 and 6 were opened) -Liquid supply: Water was supplied from the liquid supply port 8 through the plunger pump 13 at 4 parts per 100 parts of the kneaded product extrusion amount.

Result: Headspace method measurement value: resin was 900 ppm and toner was 380 ppm, and the toner odor during actual copying was also small. Toner dispersibility: When the carbon dispersion of the kneaded product was observed with an optical microscope, there was no aggregate and the dispersibility was good. Actual shooting test: Image density was 1.35 or more from the beginning to the end, and fog was 1.0 or less, which was stable and good.
The amount of toner scattered at the bottom of the developing tank after 000 sheets was as small as 7 mg, which was good.

<Example 2> ○ Kneading conditions Only the vent vacuum suction of Example 1 was changed as follows. Vent vacuum suction: Vent ports 6 and 7 were sucked with a vacuum pump. (Vent port 5 was opened)

Result: Headspace method measurement value: toner was 310 ppm, and toner odor during actual copying was also small. Toner dispersibility: Good as in Example 1. Actual shooting test: Image density was 1.35 or more from the beginning to the end, and fog was 1.0 or less, which was stable and good.
The toner scattering amount at the bottom of the developing tank after 000 sheets was as small as 5 mg, which was good.

<Comparative Example 1> ○ Kneading conditions The same as Example 1 except that the liquid was not supplied. ◯ Result Headspace method measurement value: Toner was 570 ppm, and there was a slight toner odor during actual copying.

Toner dispersibility: Carbon black was observed in the same manner as in Example 1, but many aggregates were observed. Live-action test: Initial fog was high at 1.7, about 10,0
Fog was 1.0 or less after 00 sheets. The image density was almost good. The amount of toner scattered at the bottom of the developing tank after 30,000 sheets was 52 mg, which was bad.

[Brief description of drawings]

FIG. 1 An example of a normal toner manufacturing flow

FIG. 2 is a schematic diagram of a continuous extruder.

FIG. 3 is a sectional view taken along the line AA ′ of FIG.

FIG. 4 shows an example of a kneading part screw (41) and a feeding part screw (43, 44)

FIG. 5 is a schematic view showing an example of a paddle of a screw of a feeding section.

FIG. 6 is a schematic view showing an example of a paddle of a kneading section screw.

FIG. 7 is a schematic view showing an example of a paddle of a kneading section screw.

FIG. 8 is a schematic view showing an example of a paddle of a kneading section screw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extruder main body 2 Drive part 3 Screw main body 4 Material supply port 5 Vent port 6 Vent port 7 Vent port 8 Liquid supply port 9 Kneaded material outlet 10 Feeder drive part 11 Material storage part 12 Screw feeder 13 Liquid supply device 14 Liquid storage part 15 vacuum pump 20 barrel C0 21 barrel C1 22 barrel C2 23 barrel C3 24 barrel C4 25 barrel C5 26 barrel C6 27 barrel C7 28 barrel C8 29 barrel C9 30 barrel C10 31 barrel C11 32 barrel die 41 kneading part screw 42 kneading part Screw 43 Feeding unit screw 44 Feeding unit screw 45 Feeding unit screw

Claims (5)

[Claims] 1. A method for producing an electrostatic charge image developing toner in which at least a resin and a colorant are blended and mixed, and then kneaded, pulverized and classified, wherein a liquid is supplied during the kneading step. Method for producing toner for image development. 2. The electrostatic charge image developing toner according to claim 1, wherein the apparatus used in the kneading step is a continuous extruder, and a liquid is supplied in the middle of the continuous extruder. Production method. 3. The method for producing a toner for developing an electrostatic charge image according to claim 2, wherein the liquid is supplied to the molten layer portion of the continuous extruder. 4. The method for producing an electrostatic charge image developing toner according to claim 1, wherein the supplied liquid is further removed as vapor from the kneaded material. 5. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the liquid is water.