JP3443979B2 - Method for producing toner composition - 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 composition 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 developer not requiring a carrier (magnetic toner, non-magnetic Magnetic toner) is known.

Toners contained in the developer include positively chargeable toners and negatively chargeable toners. Conventionally, as those imparting chargeability to positively chargeable toners, nigrosine dyes and quaternary ammonium salts have been used. As a compound or the like, or a charge control agent such as a metal-containing dye, or a coating agent that imparts a predetermined chargeability to a carrier has been known as a charge imparting agent to a negatively chargeable toner.

FIG. 1 shows an example of a toner manufacturing flow that is normally performed. First, a predetermined amount of materials such as a resin, a colorant, and a charge control agent are mixed, mixed, melt-kneaded by a batch type or continuous kneader, cooled, pulverized, and classified. Further, after the classified toner and the external additive are stirred and mixed, a coarse product is sieved and filled in a container. Further, the toner fine powder generated in the toner manufacturing process may be recycled for a predetermined amount to be reused in the flow mixing process and the mixing process in view of environment and production cost.

[0005]

However, when the toner performance is evaluated by repeatedly copying the toner using a conventional toner in a copying machine or the like, the image density is not stable, the fog is deteriorated, and the inside of the copying machine is deteriorated. There is a problem that a large amount of scattered toner is generated. Therefore, a first object of the present invention is to provide a method for producing a toner composition having good image characteristics and excellent image quality. A second object is to provide a method for producing a toner composition in which the image characteristics are stable even when copied over time and the contamination in the machine is small.

[0006]

As a result of various studies conducted by the present inventors, it was found that toner quality is excellent and stable by mixing a resin and a charge control agent by a specific method.
The present invention has been reached. That is, the gist of the present invention is to melt-blend after mixing at least a resin, a colorant and a charge control agent.
In the method for producing a toner composition of kneading , pulverizing and classifying ,
During mixing, wearing tree butter and a charge control agent were preliminarily mixed
A method for producing a toner composition is characterized by adding a colorant and further mixing .

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. Examples of the styrene resin (styrene or a styrene-substituted homopolymer or copolymer) include:
Polystyrene, polychlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer , Styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene-acrylic acid Phenyl copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer and styrene-phenyl methacrylate copolymer) ), Styrene-α-chloracry Methyl acetate copolymer and styrene-
Examples thereof include acrylonitrile-acrylic acid ester copolymer.

As the polyester resin, a known saturated resin,
It can be optionally used from unsaturated ones, and the composition is composed of a polyhydric alcohol and a polybasic acid, and if necessary, at least one of the polyhydric alcohol and the polybasic acid is a polyfunctional monomer having a valence of 3 or more. It may be contained. Examples of the epoxy resin include a general-purpose epoxy resin such as a polycondensate of bisphenol A and epichlorohydrin, a modified epoxy resin modified with carboxylic acid, phenol, diarylsulfonamide, etc., and an epoxy resin in which a phenol resin and an epoxy resin are blended. There is.

Other resins include vinyl chloride resin, rosin-modified maleic acid resin, phenol resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, There are polyvinyl butyral resin, polycarbonate resin and the like.

Particularly preferred resins for use in the present invention include styrene resins, saturated or unsaturated polyester resins and epoxy resins. Further, the resins are not limited to being used alone, but two or more kinds may be used in combination. The particle size distribution of the resin has a peak (Pr) of 1000
The thickness is preferably not more than μm, and more preferably not more than 800 μm. Peak (Pr) is 1000 μm
If the resin is located at a larger position, the raw materials are likely to be ubiquitous and the toner composition is not uniform, which is not preferable. The average particle diameter (Dr) of the resin is preferably about 50 to 2000 μm.

The resin may be produced by a known production method. For example, in the case of a styrene resin, it may be produced by solution polymerization, suspension polymerization, bulk polymerization, emulsion polymerization or the like, and if necessary, a low molecular weight polymer. And the method of polymerizing the high molecular weight substance may be different. When the predetermined particle size cannot be obtained in the production stage, the resin particle size may be crushed or crushed by a known mechanical means.

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 to the paper is low and good, but hot offset is likely to occur, and the toner is liable to be crushed inside the developing tank to cause a spent phenomenon in which the toner adheres to the carrier surface or 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., there are problems such as a high fixing temperature on paper and poor toner pulverizability.

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 tends to be hard agglomerated or adhered when left at a high temperature of 40 ° C. for a long time, resulting in deterioration of storage stability. However, there are problems in use such that the toner agglomerates are likely to be generated in the external addition step, and moreover, the toner agglomerates are easily attached to the screen, the side wall, etc. of the sieving device. Each test method of the resin used in the present specification will be described below.

[Particle size distribution] Laser diffraction type particle size distribution measuring device (model HEROS & GR)
It is measured by the dry method using ADIS) under the following conditions.

[0015]

[Table 1] ・ Dispersion method: Vertical descent type dispersion unit ・ Lens focal length: 2000mm ・ Measurement time: 2 sec

[Flow softening temperature (Tm)] In a flow tester (CFT-500 manufactured by Shimadzu Corporation),
Sample 1g, nozzle 1mm × 10mm die, load 30k
g, a preheating time of 50 ° C. for 5 minutes, and a temperature rise rate of 3 ° C./min. The measurement is performed.

[Glass transition temperature (Tg)] A transition (inflection) start portion 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 dye, anthraquinone dye, Colorants such as monoazo and diazo dyes and pigments may be used alone or in combination of two or more. The content of the colorant may be an amount sufficient to color the toner so that a visible image can be formed by development, and for example, resin 100
1 to 20 parts by weight, preferably 3 to 15 parts by weight, is suitable for the parts by weight.

The charge control agent used in the present invention includes:
Known positively-charged or negatively-charged charge control agents may be used alone or in combination, and the amount thereof may be selected in accordance with the desired charge amount proportion, for example, 0. It is preferably about 05 to 10 parts by weight. Examples of the positively chargeable charge control agent include nigrosine dyes, quaternary ammonium salt compounds, triphenylmethane compounds,
Examples include imidazole compounds and polyamine resins. Examples of the negatively-charged charge control agent include metal-containing azo dyes such as Cr, Co, Al and Fe, salicylic acid metal compounds, alkylsalicylic acid metal compounds, and curricarene compounds.

The melting point of the charge control agent is preferably higher than the kneading temperature during melt kneading. If the temperature is lower than the kneading temperature, the charge control agent is decomposed during melt kneading, which hinders the charging function of the toner, which is not preferable. The temperature of the melt-kneaded product is appropriately determined depending on the materials to be used, the kneader, etc., but is usually set to a temperature higher than the flow softening temperature (Tm) of the resin used, and preferably 20 ° C. higher than the flow softening temperature (Tm). The higher temperature is better. The temperature of the melt-kneaded product may be measured with a commercially available thermometer. The melting point (Mp) of the charge control agent is preferably 170 ° C. or higher, preferably 1
The temperature is preferably 80 ° C or higher, more preferably 190 ° C or higher. If the melting point is less than 170 ° C., the temperature of the melt-kneaded product is also lowered, and the dispersibility of the colorant other than the charge control agent and other internal additives in the toner becomes poor, which is apt to cause fog and toner scattering, which is not preferable.

The average particle size (Dc) of the charge control agent is 100.
It is preferably not more than μm, more preferably not more than 50 μm, and further preferably not more than 20 μm. When it is 100 μm or more, the charge control agent cannot be well dispersed in the toner, and the toner charging characteristics are deteriorated, which is not preferable. The average particle size (Dc) of the charge control agent is preferably smaller than the average particle size (Dr) of the resin, and is preferably 1/2 or less. If it is more than 1/2, the charge control agent is not well dispersed in the resin, the toner charging characteristics are deteriorated, and image defects are likely to occur, which is not preferable. Each test method of the charge control agent used in the present specification will be described below.

[Particle size distribution] Laser diffraction type particle size distribution measuring device (model HEROS & RO
It is measured under the following conditions by a dry method using DOS).

[0023]

[Table 2] ・ Dispersion method: Flow type dispersion unit ・ Dispersion air pressure: 3 bar ・ Dispersion nozzle pulling pressure: 120 mbar ・ Lens focal length: 500mm ・ Measurement time: 3 sec

[Melting point (Mp)] In a differential thermal analyzer (DTA-40 manufactured by Shimadzu Corp.), the heating rate was 10 ° C.
The peak temperature of the endothermic curve measured under the condition of / min is the melting point. The charge control agent of the present invention acts more effectively when a quaternary ammonium salt compound is used, and examples of the quaternary ammonium salt compound include compounds represented by the following general formula (I). .

[0025]

[Chemical 1] (In the formula, R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom, an alkyl group which may have a substituent or an aralkyl group which may have a substituent, and A represents a substituent. Represents an aromatic ring residue which may have)

Specific examples of R ¹ , R ² , R ³ and R ⁴ include methyl group, ethyl group, n-propyl group, iso-propyl group, butyl group, pentyl group, hexyl group, heptyl group and octyl group. , Nonyl group, decyl group, undecyl group,
Alkyl groups such as dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, stearyl group, nonadecyl group, eicosyl group, docosyl group, tetracosyl group; hydroxyl group-substituted alkyl group, halogen group-substituted alkyl group, alkoxyl group A substituted alkyl group such as a substituted alkyl group; an aralkyl group such as a benzyl group and a phenethyl group; a substituted aralkyl group such as a lower alkyl group-substituted aralkyl group, a nitro group-substituted aralkyl group, a halogen group-substituted aralkyl group, and the like. An alkyl group having 16 or less carbon atoms which may have, a benzyl group,
A lower alkyl group-substituted benzyl group, a nitro group-substituted benzyl group, and a halogen group-substituted benzyl group are preferable. Further, the number of carbon atoms of the alkyl group is preferably 12 or less, particularly R ² ,
It is preferred that R ³ and R ⁴ are the same group.

A represents an aromatic ring residue which may have a substituent, and examples thereof include an arylene group such as a phenylene group, a naphthylene group and an anthrylene group, and a phenylene group and a naphthylene group are particularly preferable. These may have a substituent, and examples of the substituent include an alkyl group, a hydroxyl group, an amino group and a halogen group, and a hydroxyl group is particularly preferable. Of the compounds represented by the above general formula (I), specific examples of the compounds suitable for use in the present invention include the compounds represented by the following structural formulas, but are not limited to these. Absent. Exemplified compound

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

[Table 5]

[0031]

[Table 6]

[0032]

[Table 7]

[0033]

[Table 8]

[0034]

[Table 9]

If desired, other internal additives may be used alone or in combination as an auxiliary agent. For example, known low-molecular-weight olefin polymers as releasing agents, metal soaps as lubricants, and magnetite as magnetic powders. Examples thereof include powder / ferrite powder, organic / inorganic filler, and the like. 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.

[Mixing Step] The feature of the present invention resides in that the resin and the charge control agent are premixed in the mixing step. In the premixing of the present invention, the resin and the charge control agent are basically mixed, but other additives may be mixed in a small amount within the range that does not impair the effects of the present invention. The amount of the charge control agent used in the premixing may be the whole amount or a part thereof. Furthermore, the number of times of mixing is 2 by gradually adding the materials.
It may be performed more than once.

Mixing of these materials may be carried out by stirring and mixing with a known mixing device, and examples of the mixing device include a double cone mixer, a V type mixer, a drum type mixer,
There are super mixer, Henschel mixer, Nauta mixer, etc. In order to preferably operate the present invention, a high-speed rotating blade mixer which has a stirring blade rotating at a high speed inside at the time of premixing and gives a shearing action to the material is preferable, and for example, a super mixer or a Henschel mixer is used. is there.
When such a mixing device is used, toner charging characteristics are improved, image stability during continuous copying is improved, and toner contamination is reduced. Although this mechanism has not been clarified, the charge control agent particles are crushed by mixing the resin and the charge control agent, and the surfaces of the resin particles are evenly sprinkled, which in turn improves the dispersion of the charge control agent in the toner. It is estimated that the toner charging characteristics are improved. The premixing and the subsequent mixing may be performed by the same mixer or different mixers.

In order to sufficiently mix the materials, the peripheral speed of the stirring blade of the mixing device should be 5 m / sec or more at the tip, and the mixing time should be 30 sec or more / time, preferably 1 minute / time or more. Good, the total time is preferably 1 minute or more, and more preferably 2 minutes or more. In addition, the peripheral speed of the stirring blade and the mixing time were
It may be changed appropriately in the subsequent mixing.

[Kneading Step] As a kneading device for melt-kneading the above mixture, either a batch type or a continuous type may be used, but in view of productivity, a uniaxial or biaxial continuous kneader may be used. For example, KTK twin-screw extruder manufactured by Kobe Steel, TEM twin-screw extruder manufactured by Toshiba Machine Co., Ltd., twin-screw extruder manufactured by KCK, PCM twin-screw extruder manufactured by Ikegai Iron Works, Kuriyama Seisakusho. A twin-screw extruder manufactured by Co. and a co-kneader manufactured by Bus Co. are preferable.

[Cooling Step] After the kneading, the kneaded material is rolled with two rolls or the like, and then subjected to a cooling step of cooling with a belt cooler, a drum cooler or the like by air cooling or water cooling. [Crushing step] The crushing step consists of a coarse crushing step and a fine crushing step. In the coarse crushing step, the kneaded product after cooling is roughly crushed by a crusher, a hammer mill, a feather mill, etc. Finely pulverize with a rotor rotary mill or the like, and pulverize stepwise to a predetermined toner particle size.

[Classification process] After grinding, an inertia classification type elbow jet, a centrifugal force classification type microplex, D
The toner is classified with an S separator or the like, and the average particle size is 3 to 1
5 μm toner is obtained. The coarse toner powder generated in the classification step may be returned to the crushing step, and the fine powder generated may be returned to the mixing step of the toner raw materials for reuse.

[External Addition Step] It is preferable that a classified toner and various known external additives are blended in a predetermined amount and agitated and mixed with a high-speed agitator such as a Henschel mixer or a super mixer that gives a shearing force to the powder.

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 depends on the external additive to be used and the average particle size and particle size distribution of the toner particles.
0.01 to 10 parts by weight, more preferably 0.00
1 to 8 parts by weight is preferred. If the mixing amount is less than 0.01 part by weight, there is no fluidity improving effect and the storage stability performance at high temperature is poor, and if the mixing amount is more than 10 parts by weight, filming occurs on the photoconductor due to partly released external additive. Undesirably, or it accumulates inside the developing tank and causes problems such as deterioration of the charging function of the developer.

[Sieving step] The externally added toner is screened by a Sato type vibrating screen, a gyro shifter, a centrifugal classifier, etc. for the purpose of removing foreign matters, coarse toner particles, and freed external additives. To be done.

[Filling Step] A container such as a bottle or a cartridge, an aluminum bag, a plastic bag or the like is filled with a predetermined amount of toner. The obtained toner is a one-component developer that does not use a carrier (a magnetic one-component toner containing a magnetic substance such as magnetite, or a non-magnetic one-component toner containing no magnetic substance), or iron powder, ferrite, or magnetite. , A two-component developer mixed with a magnetic carrier such as a magnetic resin carrier.

[0046]

By using the method for producing the toner composition of the present invention, a toner having a uniform dispersion of the charge control agent and the like can be obtained, and the image quality is excellent and the quality is stable even in the case of repeated copying. It provides great industrial benefits such as providing toner with less pollution.

[0047]

The present invention will be described in more detail with reference to the following examples. In the following examples, "parts" simply means "parts by weight". <Example 1>

[0048]

[Table 10]

Were mixed with a Henschel mixer. next,   ・ Colorant Carbon black MA-100 (Mitsubishi Chemical Corporation) 6 parts   ・ Wax polypropylene 550P (Sanyo Chemical Co., Ltd.) 2 parts Was added and mixed further.

Next, the outlet temperature was set at 18 by using a continuous twin-screw extruder.
The mixture was melt-kneaded at 0 ° C., cooled, pulverized and classified to obtain a powder having an average particle diameter of 10 μm. To 100 parts of this powder, 0.15 parts of hydrophobic silica (R972 of Nippon Aerosil Co., Ltd.) and 0.3 parts of magnetite powder (EPT-1000 of Toda Kogyo Co., Ltd.)
A part was stirred and mixed with a super mixer to obtain a black toner. A developer was prepared by mixing and stirring 4 parts of this toner and 96 parts of a ferrite carrier having an average particle size of 100 μm and surface-coated with a silicone resin. When 100,000 sheets of this developer were actually copied by a copying machine using an organic photoconductor as a photoconductor, the image density was 1.35 or more, the fog was 0.8 or less, and there was no contamination inside the machine. The amount of toner scattered on the bottom of the developing tank after 000 sheets was small. Also,
The kneaded material was sampled at a stage after kneading and cooling, and the state of dispersion of the charge control agent was observed with a microscope.

Comparative Example 1 Evaluation was made in the same manner as in Example 1 except that the resin, charge control agent, colorant and wax of Example 1 were mixed at once with a Henschel mixer. It becomes a bad image, 40,000
Fog became 1.0 or more after passing the number of sheets, deteriorated to 1.5 at the end, and the toner scattering after 100,000 sheets was about 8 times as large as that in Example 1 and there were many problems.

Example 2 Using the same raw material as in Example 1, 70 parts of resin and 2 parts of charge control agent were mixed with a Henschel mixer, and then 30 parts of resin, 6 parts of colorant and 2 parts of wax were mixed. Add and mix further. The following evaluation was performed in the same manner as in Example 1, but the image density and fog were good, and 10
The amount of toner scattered after 10,000 sheets was also small.

<Example 3> Charge control agent Compound No. (8) 2 parts As a result of evaluation in the same manner as in Example 1 except that Mp = 198 ° C. and Dc = 30 μm, the fogging was the last 1. Although it was about 0, it was almost good, and the amount of toner scattering after 100,000 sheets was small, which was good.

Example 4 Charge Control Agent Compound No (8) 2 parts Mp = 198 ° C., Dc = 81 μm were evaluated in the same manner as in Example 1, but the image characteristics were the fog last 1. However, the amount of toner scattered after 100,000 sheets was slightly larger than that in Example 1, but was almost good.

[Brief description of drawings]

FIG. 1 is an example of a normal toner manufacturing flow.

Front page continuation (72) Inventor Tokuaki Takahashi 1000 Kamoshida-cho, Midori-ku, Yokohama, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Institute (72) Inventor Osamu Ando 1000 Kamoshida-cho, Midori-ku, Yokohama, Kanagawa Mitsubishi Chemical Corporation Inside Yokohama Research Institute (56) Reference JP-A-4-204855 (JP, A) JP-A-1-237562 (JP, A) JP-A-6-95431 (JP, A) JP-A-2-118583 (JP , A) JP-A-2-300762 (JP, A) JP-A-2-161469 (JP, A) JP-A-3-213874 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G03G 9/087 G03G 9/097

Claims (7)

(57) [Claims] 1. A least a resin, after mixing a colorant and a charge control agent, melt-kneading, pulverizing, in the manufacturing method of the toner composition of classifying, upon mixing, the tree butter and a charge control agent were preliminarily mixed A method for producing a toner composition, which comprises adding a colorant and further mixing . 2. The method for producing a toner composition according to claim 1 , wherein the resin particle size distribution has no peak at 1000 μm or more. 3. The average particle diameter of the resin is 50 to 2000 μm.
The method for producing a toner composition according to claim 1 or 2 , wherein 4. The method for producing a toner composition according to claim 1, wherein the charge control agent has an average particle diameter of 100 μm or less. 5. The melting point of the charge control agent is 170 ° C. or higher.
The toner according to any one of claims 1 to 4, characterized in that
-Method for producing a composition. 6. The method for producing a toner composition according to claim 1, wherein the charge control agent is a quaternary ammonium salt compound. 7. A charge control agent represented by the general formula (I):
7. The compound according to claim 1, wherein the compound is a compound.
A method for producing the toner composition described above. [Chemical 1] (In the formula, R ¹ , R ² , R ³ and R ⁴ are a hydrogen atom and
Having an alkyl group which may have a substituent or a substituent
Represents an aralkyl group which may be present, and A has a substituent
May represent an aromatic ring residue)