JP3256445B2 - Toner and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a toner used for developing an electrostatic latent image in electrophotography, electrostatic recording, and the like, and a method for producing the toner.

[0002]

2. Description of the Related Art In electrophotography, generally, a toner having a positive or negative charge is electrostatically attached to an electrostatic latent image formed on a photoreceptor made of a photoconductive member, and then is transferred onto transfer paper. Image formation is performed by transferring and fixing the toner image. The toner used for this is a particle having an average particle diameter of 5 to 20 μm comprising a binder resin and a colorant as main components, and is controlled to an appropriate charge amount by a frictional charging member such as a carrier or a charging blade. When the charge amount of the toner is larger than an appropriate value, the image density is reduced, and when the charge amount is smaller than the appropriate value, scattering of the toner, background fogging, etc. occur, thereby deteriorating the image quality.

Therefore, as a method of controlling the charge amount of the toner to an appropriate value, there is known a method of controlling the charge amount of the toner by fixing resin fine particles having chargeability to the surface of the colored resin particles. Inorganic external additives such as silica, alumina, and titanium oxide, surface-treated with silane coupling agent and silicon oil, and resin fine particles with chargeability imparted by a charge control agent (CCA) are colored by a powder surface modification device. A method of fixing a resin particle by applying a mechanical impact force is described in JP-A-62-244056.

On the other hand, a method is disclosed in which, after externally adding resin fine particles, the colored resin particles and the resin fine particles are fixed under a high temperature condition not lower than the softening temperature of the colored resin particles.
No. 2 discloses this.

[0005]

However, in the method described in Japanese Patent Application Laid-Open No. 63-244056, in which resin fine particles are completely fixed by mechanical impact during continuous copying, spherical colored resin particles are used. However, even if the resin fine particles were fixed using non-spherical colored resin particles, the non-spherical colored resin particles became a toner having a rounded spherical shape. When the spherical toner is cleaned through the blade, the toner tends to pass between the photoconductor and the blade, which makes cleaning difficult.

In the method described in Japanese Patent Application Laid-Open No. 62-226162, the toner obtained by fixing at a temperature higher than the glass transition temperature of the colored resin particles becomes spherical,
There is a disadvantage that toners fuse together. In the manufacturing method of fixing resin fine particles having a glass transition temperature higher than the fixing treatment temperature on the surface in order to avoid fusion of toner particles, fusion of toner particles can be reduced to some extent, but fine particles having a high glass transition point However, there is a drawback in that irregularities due to the shape of the resin fine particles remain on the surface of the toner, which impairs the fixability of the toner.

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner which is excellent in charge stability of a developer during long-term use, and is excellent in fixing property, blade cleaning property and aggregation resistance, and a method for producing the same.

[0008]

Means for Solving the Problems In a toner in which fine resin particles are fixed on the surface of at least colored resin particles comprising a colorant and a binder resin, the content of the fine resin particles is 2 to the total weight of the toner. 8% by weight, the toner was non-spherical, and the toner surface was smoothed. The toner was found to be effective, and the present invention was completed.

Here, the non-spherical shape means a state in which the corners of the toner particles have not disappeared. Specifically, when the average particle diameter of the toner is L, the radius of curvature is L / 8 or less. Say toner. The term “smoothing” refers to a state in which the shape of resin fine particles adhered to the surface of the toner has disappeared. A toner having a size of not more than 05 μm is referred to as a smoothed toner. If the smoothing is not performed on the entire surface of the toner, the effect is not exhibited. It is sufficient that at least 70% or more of the surface of the toner is smoothed. Further, the content of the toner satisfying these characteristics may be at least 70% of the total toner.

Further, in the method for producing the toner, when the resin fine particles are fixed to the surface of the non-spherical colored resin particles, the peripheral speed at the tip of the stirring blade (S / m / sec) and the inside of the airflow mixer are used. Where H (° C.), the glass transition temperature of the colored resin particles is A (° C.), and the glass transition temperature of the resin fine particles is B (° C.), the following general formula is satisfied.

(A-10) ≦ H ≦ (A + 10) A ≦ B ≦ (A + 20) 5 ≦ S ≦ 20 At this time, the average particle size of the resin fine particles used is preferably in the range of 0.
It is characterized by being 3 μm or less.

Also, the viscosity of the resin fine particles used is within a range satisfying the following general formula at 140 ° C .:

10 ⁴ <η <10 ⁶ (Pa · sec)

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

As the colored resin particles constituting the present invention, non-spherical colored resin particles composed of a binder resin and a colorant and having a particle diameter of 5 to 20 μm as main components are used. Generally, the binder resin is mixed at a ratio of 45 to 95% by weight and the colorant is mixed at a ratio of 5 to 50% by weight. However, if necessary, a fixing aid such as a wax can be used.

As a method for producing non-spherical colored resin particles, for example, a mixture comprising a colorant and a binder resin is melt-kneaded by a device capable of heating and mixing such as a biaxial kneader, and then cooled and solidified. By a pulverizer such as a jet mill to a particle size of 5 to 20 μm.

Examples of the binder resin include polystyrene, styrene-acryl copolymer, styrene-acrylonitrile copolymer, acrylic resin, styrene-maleic anhydride copolymer, styrene-acryl-maleic anhydride copolymer, and polystyrene. Vinyl chloride, polyvinyl acetate, polyolefin resin, polyester resin, polyurethane resin, urethane modified polyester resin, epoxy resin, etc.
Alternatively, in addition to being used as a mixture, it can also be used as a block polymer or a graft polymer.

Examples of the coloring agent include carbon black,
Magnetic powder, or nitro, azo, stilbene azo, diphenylmethane, triphenylmethane, methine, thiazole, anthraquinone, indamine, azine, oxaazine, thiazine, sulfur dye, indigoid And phthalocyanine-based organic dyes and pigments.

On the other hand, the resin fine particles preferably have a positive or negative chargeability, and are prepared by polymerization using potassium persulfate or ammonium persulfate, amidinopropane hydrochloride, etc. as a water-soluble polymerization initiator. And a method using a monomer having a polar group such as an amino group, an amide group, a carboxylic acid, or a sulfonic acid.
Monomers that can be used include styrene, p-methylstyrene, sodium styrenesulfonate, vinylbenzyl chloride, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dimethylaminoethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate And dimethylaminoethyl methacrylate, but are not limited thereto, and these may be used alone or in a copolymerized form. By using a water-soluble polymerization initiator at the time of synthesizing the resin fine particles, uniform resin fine particles of 0.3 μm or less can be obtained.

As a method for producing a toner in which resin fine particles are fixed to the surface of non-spherical colored resin particles and the toner surface is smoothed, a temperature-controllable outer wall and a stirring blade are required to be a minimum component. Using a gas mixer such as a Henschel mixer, a super mixer, a mechano mill, etc., the peripheral speed of the tip of the stirring blade S (m / sec), the temperature in the gas mixer as H (° C.), and the glass of the colored resin particles. The transition temperature is A (° C), and the glass transition temperature of the resin fine particles is B (° C).
Is obtained by mixing and agitating the non-spherical colored resin particles and the resin fine particles under the conditions satisfying the following general formula to fix the resin fine particles on the surface of the colored resin particles.

(A-10) ≦ H ≦ (A + 10) A ≦ B ≦ (A + 20) 5 ≦ S ≦ 20 Before the fixing treatment, they may be mixed and dispersed in an atmosphere at room temperature using an airflow mixer or the like. Temperature in the airflow mixer (H
C.) is too low relative to the glass transition temperature (A.degree. C.) of the colored resin particles, the fixation is weak, and if it is too high, the toner tends to be spherical. The mechanical energy received from the rotation of the stirring blade and the collision energy of the particles cause the colored resin particles to adhere to the resin fine particles. If this energy is small, sufficient smoothing is difficult to occur, and if it is too large, the toner tends to be spherical. If the glass transition temperature of the resin fine particles is low, toner aggregation is likely to occur, and if the glass transition temperature is high, it becomes difficult to smooth the toner without making it spherical.

If the particle size of the resin fine particles to be fixed is large, it becomes difficult to smooth the toner surface, and the fixing property is deteriorated.
The average particle size of the resin fine particles is preferably 0.3 μm or less. Further, if the melt viscosity of the resin fine particles is too high, the fixability deteriorates, and if the melt viscosity is too low, toner aggregation is likely to occur, so that the viscosity within a certain range is required. Specifically, 14
The viscosity (Pa · sec) of the resin fine particles at 0 ° C. is desirably within a range satisfying the following general formula.

10 ⁴ <η <10 ^{6 When} the glass transition temperature (A ° C.) of the colored resin particles is too low, the storage stability of the toner tends to deteriorate, and when the glass transition temperature is too high, the fixability tends to deteriorate. Therefore, the glass transition temperature is preferably in the range of 40 to 60C.

Further, when the content of the resin fine particles having a high glass transition temperature is increased, the fixability of the toner is deteriorated, and when the content is too small, the preservability under a high temperature environment is deteriorated. The preferred range is ８8% by weight.

The toner obtained in the present invention may be used in combination with a known external additive such as silica, titanium oxide, or alumina fine particles for the purpose of imparting fluidity or abrasiveness. It can be used as a brush developer and also as a one-component developer.

Hereinafter, the present invention will be described specifically. In addition,
All "parts" described in the embodiments indicate parts by weight.

(Embodiment 1) 100 parts of styrene-acrylic copolymer resin (Tg 55 ° C., Mn = 3 × 10 ⁸ , MW = 2 × 10 ⁵ ) 100 parts Carbon plaque (MA-1OO manufactured by Mitsubishi Kasei Co., Ltd.) 6 parts Providen wax (Viscol 550P manufactured by Sanyo Chemical Co., Ltd.) 2 parts The above Tg is the glass transition point, Mn is the number average molecular weight, M
W represents a weight average molecular weight.

The above-mentioned material is stirred for 2 minutes by a super mixer, melt-kneaded by a twin-screw kneader, pulverized by a hammer mill and a jet mill, and subjected to air flow classification of colored resin particles having an average particle diameter of 10 μm to form a non-spherical shape. To obtain colored resin fine particles. Next, 8 parts of the following resin fine particles exhibiting positive chargeability were added to 100 parts of the colored resin particles.

Methyl methacrylate-butyl methacrylate (MMA-BMA) copolymer resin fine particles (TN-102, Soken Chemical Co., Ltd.) (Tg 65 ° C., average particle size 0.15 μm, melt viscosity at 140 ° C. (3 × 10 ⁵⁾ Pa · sec)) Next, a fixing process was performed using a super mixer under the following conditions.

The peripheral speed of the tip of the stirring blade is 10 m / sec. The temperature in the airflow mixer is 50 ° C., and the mixing time is 30 minutes. As a result, a toner having positive chargeability was obtained. This toner was observed with an electron microscope (hereinafter referred to as S
Recorded as EM observation. As a result, 70% or more of the toner surface was smoothed, and 70% or more of angular particles having a curvature radius of 1 μm or less.

(Embodiment 2) To 100 parts of the colored resin particles used in Embodiment 1, 5 parts of the following resin fine particles exhibiting positive chargeability were added.

MMA-BMA copolymer resin particles (TN-104 manufactured by Soken Chemical Co., Ltd.) (Tg 70 ° C., particle size 0.15 μm, melt viscosity at 140 ° C. 8 × 10 ⁵ Pa · sec) Next, a super mixer was used. The fixing treatment was performed under the following conditions.

The peripheral speed of the tip of the stirring blade is 10 m / sec. The temperature in the airflow mixer is 50 ° C. The mixing time is 30 minutes. To 100 parts of this powder, 0.3 parts of hydrophobic silica (Nippon Aerosil R-972) is added. In addition, a toner exhibiting positive chargeability was obtained. This toner was observed by SEM (hereinafter, SEM).
This is referred to as observation. As a result, 70% or more of the toner surface was smoothed, and 70% or more of angular particles having a curvature radius of 1 μm or less.

(Embodiment 3) To 100 parts of the colored resin particles used in Embodiment 1, 5 parts of the following resin fine particles exhibiting positive chargeability were added.

MMA-BMA copolymer resin particles (TN-105, Soken Chemical Co., Ltd.) (Tg 70 ° C., particle size 0.15 μm, melt viscosity at 140 ° C. (8 × 10 ⁵ Pa · sec)) A fixing treatment was performed under the following conditions.

The peripheral speed of the tip of the stirring blade 20 m / sec The temperature in the airflow mixer 50 ° C. Mixing time 80 minutes 0.3 part of hydrophobic silica (R-972 manufactured by Nippon Aerosil Co.) is externally added to 100 parts of the powder. As a result, a toner having positive chargeability was obtained. When this toner was observed with an SEM, 70% or more of the toner surface was smoothed and the radius of curvature was 1
More than 70% of the particles had an angle of less than μm.

(Embodiment 4) To 100 parts of the colored resin particles used in Embodiment 4, 2 parts of the following resin particles exhibiting positive chargeability were added.

MMA-BMA copolymer resin fine particles (TN-104 manufactured by Soken Chemical Co., Ltd.) (Tg 70 ° C., particle size 0.15 μm, melt viscosity at 140 ° C. 8 × 10 ⁵ Pa · sec) Next, a super mixer was used. The fixing treatment was performed under the following conditions.

Peripheral speed of the tip of the stirring blade 10 m / sec Temperature in the airflow mixer 50 ° C. Mixing time 80 minutes 0.3 part of hydrophobic silica (R-972 manufactured by Nippon Aerosil Co.) was externally added to 100 parts of the powder. As a result, a toner having positive chargeability was obtained. When this toner was observed with an SEM, 70% or more of the toner surface was smoothed and the radius of curvature was 1
More than 70% of the particles had an angle of less than μm.

(Comparative Example 1) 100 parts of the colored resin particles and resin fine particles (TN-10 manufactured by Soken Chemical Co., Ltd.) used in Embodiment 2
4) 5 parts were added, and a fixing treatment was performed using a super mixer under the following conditions.

Peripheral speed of the tip of the stirring blade 10 m / sec Temperature in the air mixer 40 ° C. Mixing time 30 minutes 0.3 part of hydrophobic silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) is externally added to 100 parts of the powder. As a result, a toner having positive chargeability was obtained. When this toner was observed by SEM, 70% or more of angular particles having a radius of curvature of 1 μm or less were found.
The entire surface of the toner had irregularities of 0.05 μm or more.

Comparative Example 2 100 parts of the colored resin particles and resin fine particles (TN-10 manufactured by Soken Chemical Co., Ltd.) used in the second embodiment were used.
4) 5 parts were added, and a fixing treatment was performed using a super mixer under the following conditions.

The peripheral speed of the tip of the stirring blade is 30 m / sec. The temperature in the airflow mixer is 50 ° C. The mixing time is 80 minutes 0.3 parts of hydrophobic silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) is externally added to 100 parts of the powder. As a result, a toner having positive chargeability was obtained. When this toner was observed by SEM, 70% or more of the toner surface was smoothed, but the radius of curvature was 2 μm.
There were almost no angular particles less than m, and the shape was almost spherical.

(Comparative Example 3) 100 parts of the colored resin particles used in the second embodiment and resin fine particles (TN-10 manufactured by Soken Chemical Co., Ltd.)
4) One part was added, and a fixing treatment was performed using a super mixer under the following conditions.

Peripheral speed of tip of stirring blade 10 Om / sec Temperature in airflow mixer 50 ° C. Mixing time 30 minutes 0.3 part of hydrophobic silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) is externally added to 100 parts of this powder. As a result, a toner having positive chargeability was obtained. When this toner was observed with an SEM, 70% or more of the surface of the toner was smoothed, and 70% or more of angular particles having a radius of curvature of 1 μm or less. The toner produced in Comparative Example 3 is a toner having a non-spherical shape and smoothness, but having a small content of resin fine particles.

Each of the toners according to Embodiments 1 to 4 and Comparative Examples 1 to 3 was mixed with 100 parts of a ferrite carrier coated with 4 parts of a fluororesin to prepare a developer. Using these developers, a copying machine (SF-830 manufactured by Sharp Corporation) is used.
When the continuous copy test of 10,000 sheets was performed in 0), the results shown in Table 1 were obtained.

[0047]

[Table 1]

As is clear from the results shown in Table 1, the toner according to the present invention has excellent fixing properties, cleaning properties, and aggregation resistance.
The surface image density is high even for continuous copying, and an image without fog is given.

[0049]

According to the toner of the present invention, fine resin particles are fixed on the surface of the colored resin particles in a smoothed state, and
Since the toner has a non-spherical shape, the toner has excellent fixing properties and cleaning properties, and has high charging characteristics, fluidity, and cohesion resistance, so that excellent image quality can be maintained even when used for a long time.

Further, according to the method for producing a toner according to the present invention, even when resin fine particles are fixed on non-spherical colored resin particles, the toner surface is smoothened in a non-spherical shape without changing the shape to a spherical shape. Can be manufactured.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Satoshi Yuyoshi 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-8-211647 (JP, A) JP-A-1 -105261 (JP, A) JP-A-3-265863 (JP, A) JP-A-7-191494 (JP, A) JP-A-3-170945 (JP, A) JP-A-3-61953 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (4)

(57) [Claims] 1. A toner in which resin fine particles are fixed on the surface of colored resin particles, wherein the content of the resin fine particles is 2 to the total weight of the toner.
8% by weight, and the shape of the toner is a curvature, where L is the average particle diameter of the toner.
A non-spherical shape having a corner having a radius of L / 8 or less , wherein the toner surface is 0.1 μm
When the unevenness is measured at the pitch, the size of the unevenness is 0.05μ
m, which is smoothed to not more than m . 2. When the resin fine particles are fixed to the surface of the non-spherical colored resin particles by an airflow mixer having stirring blades, the peripheral speed of the tip of the stirring blades S (m / sec);
When the temperature inside the airflow mixer is H (° C.), the glass transition temperature of the colored resin particles is A (° C.), and the glass transition temperature of the resin fine particles is B (° C.), the following general formula is satisfied. The method for producing a toner according to claim 1. (A-10) ≦ H ≦ (A + 10) A ≦ B ≦ (A + 20) 5 ≦ S ≦ 20 3. An average particle diameter of the resin fine particles is 0.3 μm.
3. The method according to claim 2, wherein m is equal to or less than m. 4. The method according to claim 2, wherein the viscosity of the resin fine particles is within a range satisfying the following general formula at 140 ° C. 10 ⁴ <η <10 ⁶ (Pa · sec)