JP4831023B2 - Electrophotographic toner - Google Patents

Description

  The present invention relates to an electrophotographic toner, and more particularly, to an electrophotographic toner having excellent fluidity.

  In recent years, as electrophotographic printers have shifted to miniaturization, toners are required to have a smaller particle size. However, reducing the particle size of the toner causes problems such as a decrease in bulk density, deterioration in agglomeration, and deterioration in fluidity. In order to solve these problems, a large amount of a surface treatment agent is added to the small particle size toner, or the surface shape is spheroidized by heat or a mechanical method, or a technique such as a chemical polymerization toner is used. It has been. However, neither method is sufficient to solve these problems.

  In general, a charge control agent is added to the electrophotographic toner in order to improve the charge rising. However, in the case of a small particle size toner, only the charge rising is obtained by adding the charge control agent. However, there is a problem that the entire charging property is increased and the charging is excessively performed. Therefore, the toner causes electrostatic aggregation and the fluidity is deteriorated.

The present inventors have studied to solve such a problem of deterioration of fluidity not by the surface treatment of the toner particles but by the surface treatment of the pigment contained in the toner particles.
Until now, many methods for surface-treating pigments have been known (for example, Patent Documents 1 to 10). However, all of these methods use pigments on the surface in order to achieve high dispersion of the pigments and high chargeability of the toner. There was nothing to improve the fluidity of the toner.

Japanese Patent Laid-Open No. 11-65173

Japanese Patent Laid-Open No. 11-52624

Japanese Patent Laid-Open No. 2004-341084

JP-A 61-149969

JP-A-11-52622

JP-A-2005-324800

Japanese Patent Laid-Open No. 7-160038

Japanese Unexamined Patent Publication No. 62-005256

JP-A-53-17737

JP 58-7648 A

  The present invention has been made under the circumstances as described above, and an object thereof is to provide an electrophotographic toner having excellent fluidity.

In order to solve the above problems, one embodiment of the present invention is an electrophotographic toner including a binder resin and a colorant, wherein the colorant includes a pigment that has been surface-treated with a conductive polymer. An electrophotographic toner is provided.
As the conductive polymer, a dispersible polyaniline represented by the following formula (1) can be used.

（式中、Ｘ１、Ｘ２及びＸ３は、同一でも異なっていてもよく、水素、スルホン基、カルボキシル基、または水酸基を示し、Ｙ１、Ｙ２及びＹ３は、同一でも異なっていてもよく、水素、アルキル基、メトキシ基、エトキシ基、アミノ基、ニトロ基、シアノ基、アルデヒド基、アセトアニリド基、クロル基、またはメルカプト基を示す。ｍおよびｎは正の数である）。
また、前記結着樹脂として、ポリエステルを用いることができる。

(Wherein X1, X2 and X3 may be the same or different and each represents hydrogen, a sulfone group, a carboxyl group or a hydroxyl group; Y1, Y2 and Y3 may be the same or different; Group, methoxy group, ethoxy group, amino group, nitro group, cyano group, aldehyde group, acetanilide group, chloro group, or mercapto group (m and n are positive numbers).
Moreover, polyester can be used as the binder resin.

  The electrophotographic toner according to an aspect of the present invention can be manufactured by a pulverization method.

  According to one embodiment of the present invention, an electrophotographic toner having excellent fluidity can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.
The electrophotographic toner according to the embodiment of the present invention is characterized in that a colorant containing a pigment surface-treated with a conductive polymer is used.
Usually, a charge control agent is added to the electrophotographic toner. However, particularly in the case of a small particle size toner, the toner is excessively charged by adding the charge control agent. There was a problem that fluidity deteriorated. On the other hand, by using a pigment surface-treated with a conductive polymer, the level of charging can be lowered as a whole, thereby improving fluidity.

  The conductive polymer used for the surface treatment of the pigment is transparent so as not to impair the function of the pigment, and if it has conductivity, the purpose of improving fluidity can be achieved. It must be capable of forming a film for surface treatment, and for that purpose it must be a polymer.

  Moreover, in order to surface-treat a pigment, it is necessary to be able to melt | dissolve in a solvent, As a preferable example for that, dispersible polyaniline represented by following formula (1) can be mentioned.

（式中、Ｘ１、Ｘ２及びＸ３は、同一でも異なっていてもよく、水素、スルホン基、カルボキシル基、または水酸基を示し、Ｙ１、Ｙ２及びＹ３は、同一でも異なっていてもよく、水素、アルキル基、メトキシ基、エトキシ基、アミノ基、ニトロ基、シアノ基、アルデヒド基、アセトアニリド基、クロル基、またはメルカプト基を示す。ｍおよびｎは正の数である）。

(Wherein X1, X2 and X3 may be the same or different and each represents hydrogen, a sulfone group, a carboxyl group or a hydroxyl group; Y1, Y2 and Y3 may be the same or different; Group, methoxy group, ethoxy group, amino group, nitro group, cyano group, aldehyde group, acetanilide group, chloro group, or mercapto group (m and n are positive numbers).

In addition to the dispersible polyaniline, no examples of dispersible or soluble conductive polymers have been reported.
The amount of the conductive polymer surface-treated on the pigment is preferably, for example, 0.1 to 5% by mass with respect to the pigment.

Examples of the surface treatment method of the pigment include a method in which a dispersion in which the pigment is dispersed in a solution containing a conductive polymer is spray-dried by a spray dryer, but other methods can also be used.
Polyester can be preferably used as the binder resin, but polystyrene can also be used.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
The surface treatment with the conductive polymer of the pigment used in each example was performed as follows.
Conductive surface treatment (1)
To a toluene solution in which 3 g of aniline, 6.3 g of dodecylbenzenesulfonic acid and 0.01 g of trimethylaniline were dissolved, 5.4 mL of a 6 mol / L hydrochloric acid aqueous solution and 1 g of tetrabutylammonium bromide were added and cooled to 0 ° C.
To this toluene / water mixed solution, 53.1 g of a 15.3% by mass ammonium persulfate aqueous solution was added, and the mixture was stirred for 10 hours while maintaining at 0 ° C.
After completion of the reaction, toluene and an aqueous ammonia methanol solution with an ammonia concentration of 0.32 mol / L were added to the reaction solution in this order, and the mixture was stirred and allowed to stand.
The reaction solution was separated into two layers of toluene and water, then the aqueous layer was removed, and then the washing operation with an aqueous methanol solution was repeated four times to obtain a polyaniline toluene dispersion (polyaniline content 1.16% by mass). Got.
5 parts by mass of a magenta pigment (Seika First Carmine 1476T-7 (manufactured by Dainichi Seika Co., Ltd.)) is added to 100 parts by mass of the polyaniline toluene dispersion thus obtained, and the mixture is sufficiently stirred. After diluting with toluene, use a spray dryer equipped with a nozzle with a droplet refining mechanism (manufactured by Fujisaki Electric Co., Ltd., micro mist dryer MDP-050, nozzle type is a circle edge nozzle, drying tower dimensions are 2500 mmφ x 4800 mmH) Then, spray drying was performed to obtain a conductive surface-treated magenta pigment (M1).

Similarly, cyan pigment (cyanine blue 4920 (manufactured by Dainichi Seika Co., Ltd.)), yellow pigment (paliotol yellow D1155 (manufactured by BASF Japan Ltd.)), carbon black (MOGUL-L (Cabot Specialty Chemicals Inc.) The surface treatment was carried out on the product, and a conductive surface-treated cyan pigment (C1), a conductive surface-treated yellow pigment (Y1), and a conductive surface-treated black pigment (B1) were obtained.
Conductive surface treatment (2)
2 parts by weight of polyaniline (emeraldine base, trade name: PANIPOLPA, manufactured by Panipo1 Co., Ltd.) was uniformly dissolved in a mixture of 20 parts by weight of N-vinylpyrrolidone and 2 parts by weight of water to obtain a blue-violet polyaniline solution. .
This polyaniline solution was dropped into a mixed liquid consisting of 20 parts by mass of styrene, 5 parts by mass of butyl acrylate, and 2 parts by mass of 2-acrylamido-2-methyl-1-propanesulfonic acid, while stirring with a homogenizer. A uniformly dispersed dark green monomer mixture was obtained.
In a reactor equipped with a thermometer, a cooling tube, a nitrogen introduction tube, a dropping funnel, and a stirrer, 140 parts by mass of ion-exchanged water, a surfactant (trade name: Eleminol SCZ-35, polyoxyethylene polycyclic phenyl ether, (HLB: 14.6, manufactured by Sanyo Chemical Co., Ltd.) 3 parts by mass was charged and dissolved with stirring while blowing nitrogen gas.
A dark green monomer mixture in which the polyaniline was uniformly dispersed was placed in a dropping funnel, and 1/10 of the mixture was dropped into the reactor. Subsequently, 5 parts by mass of a 20% aqueous solution of 2,2′-azobis (2-amidinopropane) dihydrochloride was added.
After carrying out the polymerization reaction at 70 ° C. for 30 minutes, the remaining monomer mixture was added dropwise over 4 hours. Furthermore, after completion of the dropping, a polymerization reaction was carried out at the same temperature for 2 hours to obtain a polyaniline-containing composition having a non-volatile content of 29% and an emulsion polymer having a sulfonic acid group as a dopant and a polyaniline content of 1.0%. .
After adding 5 parts by mass of a magenta pigment (Seika First Carmine 1476T-7 (manufactured by Dainichi Seika Co., Ltd.)) to 100 parts by mass of this polyaniline-containing composition, the mixture is sufficiently stirred and diluted with 100 parts by mass of water. , Spray drying using a spray drier (manufactured by Fujisaki Electric Co., Ltd., micro mist drier MDP-050, nozzle type is a circle edge nozzle, drying tower dimensions are 2500 mmφ × 4800 mmH) provided with a nozzle having a droplet refining mechanism The conductive surface-treated magenta pigment (M2) was obtained.

Similarly, cyan pigment (cyanine blue 4920 (manufactured by Dainichi Seika Co., Ltd.)), yellow pigment (paliotol yellow D1155 (manufactured by BASF Japan)), carbon black (MOGUL-L (capote specialty chemicals) Ink Co., Ltd.)) was subjected to surface modification to obtain a conductive surface-treated cyan pigment (C2), a conductive surface-treated yellow pigment (Y2), and a conductive surface-treated black pigment (B2).
Conductive surface treatment (3)
To 100 parts by mass of commercially available ORMECON: D1033W (manufactured by Nissan Chemical Industries, Ltd.), 5 parts by mass of magenta pigment (Seika First Carmine 1476T-7 (manufactured by Dainichi Seika Co., Ltd.)) is added and stirred sufficiently. After being diluted with 100 parts by mass of water, a spray dryer (manufactured by Fujisaki Electric Co., Ltd., Micro Mist Dryer MDP-050, provided with a nozzle having a droplet refining mechanism, nozzle type is a circle edge nozzle, and drying tower dimensions are (2500 mmφ × 4800 mmH) was spray-dried to obtain a conductive surface-treated magenta pigment (M3).

Similarly, cyan pigment (cyanine blue 4920 (manufactured by Dainichi Seika Co., Ltd.)), yellow pigment (paliotol yellow D1155 (manufactured by BASF Japan Ltd.)), carbon black (MOGUL-L (Cabot Specialty Chemicals Inc.) The surface modification was carried out on the product (made by Co., Ltd.) to obtain a conductive surface-treated cyan pigment (C3), a conductive surface-treated yellow pigment (Y3), and a conductive surface-treated black pigment (B3).
Example 1
100 parts by mass of a polyester resin (manufactured by Kao Corporation: Tm135 ° C.), 5 parts by mass of a conductive surface-treated magenta pigment (M1), 3 parts by mass of a release agent (No. 1 Carnauba wax: manufactured by Nippon Wax Co., Ltd.), and 1 part by mass of a charge control agent (E84: Orient Chemical Co., Ltd.) was thoroughly mixed with a Henschel mixer, melted and kneaded with a twin screw extruder, cooled, and then a flowable counter jet mill “200AFG” (Hosokawa Micron) And finely pulverized using a TSP toner separator “200TSP” (manufactured by Hosokawa Micron Co., Ltd.) to obtain a powder having a mass average particle diameter of 6.0 μm.
To 100 parts by mass of the obtained powder, 1.5 parts by mass of hydrophobic silica “RX200” (manufactured by Nippon Aerosil Co., Ltd.) as an external additive was added, and 3200 r / min for 180 seconds with a 10 liter Henschel mixer. The mixture was stirred and the powder was subjected to a surface treatment to obtain a magenta toner.

Similarly, cyan toner, yellow toner, and black toner were obtained using conductive surface-treated cyan pigment (C1), conductive surface-treated yellow pigment (Y1), and conductive surface-treated black pigment (B1), respectively. .
Example 2
100 parts by mass of polyester resin (manufactured by Kao Corporation, Tm: 135 ° C.), 5 parts by mass of conductive surface-treated magenta pigment (M2), 3 parts by mass of release agent (No. 1 carnauba wax: manufactured by Nippon Wax Co., Ltd.) , And 1 part by mass of a charge control agent (E84: manufactured by Orient Chemical Co., Ltd.) are thoroughly mixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, cooled, and then flowable counter jet mill “200AFG”. ”(Made by Hosokawa Micron Co., Ltd.) and fine powder classification using TSP toner separator“ 200TSP ”(made by Hosokawa Micron Co., Ltd.) to obtain a powder having a mass average particle size of 6.0 μm. It was.
To 100 parts by mass of the obtained powder, 1.5 parts by mass of hydrophobic silica “RX200” (manufactured by Nippon Aerosil Co., Ltd.) is added as an external additive, and rotated at 3200 r / min with a 10-liter Henschel mixer. The powder was stirred for 180 seconds, and the powder was subjected to surface treatment to obtain a magenta toner.

Similarly, cyan toner, yellow toner, and black toner were obtained using conductive surface-treated cyan pigment (C2), conductive surface-treated yellow pigment (Y2), and conductive surface-treated black pigment (B2), respectively. .
Example 3
100 parts by mass of polyester resin (manufactured by Kao Corporation, Tm: 135 ° C.), 5 parts by mass of electroconductive surface-treated magenta pigment (M3), 3 parts by mass of release agent (No. 1 carnauba wax: manufactured by Nippon Wax Co., Ltd.) , And 1 part by mass of a charge control agent (E84: manufactured by Orient Chemical Co., Ltd.) are thoroughly mixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, cooled, and then flowable counter jet mill “200AFG”. ”(Made by Hosokawa Micron Co., Ltd.) and fine powder classification using TSP toner separator“ 200TSP ”(made by Hosokawa Micron Co., Ltd.) to obtain a powder having a mass average particle size of 6.0 μm. It was.
To 100 parts by mass of the obtained powder, 1.5 parts by mass of hydrophobic silica “RX200” (manufactured by Nippon Aerosil Co., Ltd.) is added as an external additive, and rotated at 3200 r / min with a 10-liter Henschel mixer. The powder was stirred for 180 seconds, and the powder was subjected to surface treatment to obtain a magenta toner.

Similarly, cyan toner, yellow toner, and black toner were obtained using conductive surface-treated cyan pigment (C3), conductive surface-treated yellow pigment (Y3), and conductive surface-treated black pigment (B3), respectively. .
Comparative Example 1
100 parts by mass of polyester resin (manufactured by Kao Corporation, Tm: 135 ° C.), 4 parts by mass of magenta pigment (Seika First Carmine 1476T-7 (manufactured by Dainichi Seika Co., Ltd.)), charge control agent (LR147: Nippon Carlit ( Co., Ltd.) 1 part by mass and release agent (No. 1 Carnauba Wax: Nippon Wax Co., Ltd.) 3 parts by mass were sufficiently mixed with a Henschel mixer, then melt-kneaded with a twin screw extruder and cooled. And then finely pulverized using a fluid counter jet mill “200AFG” (manufactured by Hosokawa Micron Co., Ltd.), followed by a fine powder classification step using a TSP toner separator “200TSP” (manufactured by Hosokawa Micron Co., Ltd.) A powder having a diameter of 6.0 μm was obtained.
To 100 parts by mass of the obtained powder, 1.5 parts by mass of hydrophobic silica “RX200” (manufactured by Nippon Aerosil Co., Ltd.) is added as an external additive, and the rotational speed is 3200 r / min with a 10 liter Henschel mixer. Was stirred for 180 seconds, and the powder was subjected to surface treatment to obtain a magenta toner.

  Similarly, a cyan pigment (cyanine blue 4920 (manufactured by Dainichi Seika Co., Ltd.)), a yellow pigment (paliotoll yellow D1155 (manufactured by BASF Japan)), and carbon black (MOGUL-L (Cabot Specialty) Cyan Toner, Yellow Toner, and Black Toner were manufactured using Chemicals, Inc.

For each of the four color toners of Examples 1 to 3 and Comparative Example 1, the mass-based mass average diameter and coefficient of variation, bulk density, angle of repose, degree of compression, spatula angle, cohesion, and fluidity index were measured. Each characteristic was evaluated.
The inspection, measurement, and evaluation conditions for each characteristic are as follows.

1. As the particle size distribution measuring device, a multisizer type II or IIe (manufactured by Coulter Co., Ltd.), a Coulter counter, and an interface (manufactured by Nikkiki Co., Ltd.) for outputting the number distribution and volume distribution to this are used. Connected a personal computer.
Using a special grade or first grade sodium chloride as the electrolyte, a 1% NaCl aqueous solution is prepared.
As a measuring method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and then measured using a Coulter counter multisizer type II using a 100 μm aperture.
The volume and number of toners are measured to calculate the volume distribution and the number distribution, and the mass-based mass average diameter and coefficient of variation obtained from the volume distribution are obtained.

2. Bulk density Using a bulk specific gravity meter (JIS-K5101, manufactured by Tsutsui Rikagaku Co., Ltd.), the sample was left in a laboratory at room temperature 23 ± 3 ° C. and humidity 50 ± 10% for 24 hours, and then the bulk density was measured. Do.
3. Angle of repose 150 g of toner is passed through a mesh having an opening of 710 μm, and the toner is deposited on a circular table having a diameter of 8 cm. At this time, the toner is deposited so that the toner overflows from the end of the table. At this time, an angle formed between the ridge line of the toner deposited on the table and the circular table surface is measured with a laser beam, and this is defined as an angle of repose.

4). Compressibility Degree of compression is determined by the following equation from loosely packed bulk density (relaxed apparent specific gravity, “A”) and tapping bulk density (hardened apparent specific gravity, “P”).
Compressibility (%) = 100 (PA) / P
The loose apparent specific gravity is, for example, that 150 g of toner is gently poured into a cup having a diameter of 5 cm, a height of 5.2 cm, and a capacity of 100 ml, and when the toner is filled in a measuring cup, the toner surface is ground and the cup is filled. It is obtained by calculating the specific gravity of the toner filled in the cup from the amount of toner and the capacity of the cup.

  For the apparent apparent specific gravity, for example, the attached cap is added to the measuring cup used at the loose apparent specific gravity, the toner is filled in the cup, the cup is tapped 180 times, the cap is removed, and the cup is piled up. The excess toner is removed, and the specific gravity of the toner filled in the cup is calculated from the amount of toner filled in the cup and the capacity of the cup. Both apparent specific gravity values are inserted into the above formula to determine the degree of compression.

5). Spatula angle A 3 cm × 8 cm spatula is placed in contact with the bottom of a bat having a size of 10 cm × 15 cm, and toner is deposited on the spatula. At this time, the toner is deposited so as to rise on the spatula. Next, only the bat is gently lowered, and the inclination angle of the toner side surface remaining on the spatula is measured with a laser beam. Then, after applying an impact once with a shocker attached to the spatula, the spatula angle is measured again. The average of this measured value and the measured value before giving an impact is defined as a spatula angle.

6). Aggregation degree of toner A sieve is set on a vibration table in the order of openings of 250 μm, 150 μm, and 75 μm from the top. The vibration swing width is 1 mm, the vibration time is 20 seconds, and 5 g of toner is gently put on the top of the stacked sieves and vibrated. After the vibration is stopped, the mass of toner remaining on each sieve is measured. The mass of the toner remaining on each sieve is substituted into the following equation, and the values of a, b, and c are obtained from each equation. The sum of a, b and c is defined as the degree of aggregation (%).

a = (amount of toner remaining on upper screen) ÷ 5 (g) × 100
b = (amount of toner remaining on the middle screen) ÷ 5 (g) × 100 × 0.6
c = (amount of toner remaining on the lower screen) ÷ 5 (g) × 100 × 0.2
Aggregation degree (%) = a + b + c
7). Fluidity index The fluidity index is described in detail in Japanese Patent Publication No. 51-14278, Japanese Patent Application Laid-Open No. 2003-173046, and the like. In the present invention, the repose angle, the compression degree, the spatula angle, and the cohesion degree are described. The parameters obtained from the measurement method (Powder Tester P-100: manufactured by Hosokawa Micron Co., Ltd.) are converted into the index from the conversion table of Carr's fluidity index shown in Table 1 below (see Chemical Engineering. Jan. 18.1965). Convert and use the sum of the indices as the liquidity index.

実施例１〜３及び比較例１のそれぞれ４色のトナーについて、上記各特性を測定した結果を下記表２及び表３に示す。

Tables 2 and 3 below show the results of measuring the above characteristics of the four color toners of Examples 1 to 3 and Comparative Example 1, respectively.

上記表２及び表３から、実施例１〜３の４色のトナーは、すべての特性について優れた性能を示し、従って、優れた流動性を示しているのに対し、比較例１の４色のトナーは、すべての特性について実施例１〜３のトナーよりも劣った性能を示し、従って、流動性が劣っていることがわかる
その結果、実施例１〜３の４色のトナーを用いることにより、トナーカートリッジの充填量を増加することが可能となり、長寿命のトナーカートリッジをユーザーに提供することができる。
またトナーカートリッジの充填速度や搬送性も向上し、ハンドリングの良好な電子写真トナーを提供することができる。

From the above Tables 2 and 3, the four color toners of Examples 1 to 3 showed excellent performance in all properties, and thus showed excellent fluidity, whereas the four colors of Comparative Example 1 The toner of No. 1 shows inferior performance to the toners of Examples 1 to 3 in all characteristics, and thus it is found that the fluidity is inferior. As a result, the four color toners of Examples 1 to 3 are used. This makes it possible to increase the filling amount of the toner cartridge and provide the user with a long-life toner cartridge.
Further, the filling speed and transportability of the toner cartridge are improved, and an electrophotographic toner with good handling can be provided.

Claims (4)

  An electrophotographic toner comprising a binder resin and a colorant, wherein the colorant comprises a pigment surface-treated with a conductive polymer. 2. The electrophotographic toner according to claim 1, wherein the conductive polymer is a dispersible polyaniline represented by the following formula (1).

(Wherein X1, X2 and X3 may be the same or different and each represents hydrogen, a sulfone group, a carboxyl group or a hydroxyl group; Y1, Y2 and Y3 may be the same or different; Group, methoxy group, ethoxy group, amino group, nitro group, cyano group, aldehyde group, acetanilide group, chloro group, or mercapto group (m and n are positive numbers).   The electrophotographic toner according to claim 1, wherein the binder resin is polyester.   The electrophotographic toner according to claim 1, which is produced by a pulverization method.