JPH03184057A - Toner for image forming device - Google Patents

Abstract

PURPOSE:To easily obtain the toner having high dispersibility by incorporating a charge control component having pH>=4.0 hydrogen ion concn. index and a binder resin having an acidic group in the molecule as raw materials. CONSTITUTION:The charge control component having pH>=4.0 hydrogen ion concn. index and the binder resin having the acidic group in the molecule are used as the raw materials of the toner. The wettability of the charge control component and binder resin of the toner is improved in this case and the sepn. of the raw materials from each other at the time of mixing and kneading is prevented. The respective raw materials are thus uniformly dispersed in the toner particles in the state of the good wettability. The image quality is improved in this way and the life of the toner is prologned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a toner for an image forming apparatus used for development in an image forming apparatus such as an electrophotographic apparatus.

(Prior Art) In an image forming apparatus such as a copying machine, in order to obtain a copied image from a document, generally, 4;
A two-electrostatic process and an exposure process are performed to form an electrostatic latent image corresponding to the original image. Next, a toner containing a dye or 45 colorant is attached to this electrostatic δ5 image, a developing process is performed, and the formed toner image is transferred to a sheet of paper, etc., and is made to run on the paper using heat, pressure, light, etc. , a duplicate image is obtained. on the other hand,
For the photoreceptor, a cleaning process and a static elimination process are performed after the transfer for the next copying process.

There are various developing methods used in the developing process for attaching toner to the electrostatic latent image, such as a casket developing method, a magnetic brush developing method, a powder cloud developing method, a fur brush developing method, and a jumping developing method. It has been implemented. These methods can be roughly divided into methods that use magnetic force to transport the developer and methods that do not use magnetic force. Furthermore, among the methods that use magnetic force, magnetic powder is kneaded into the toner,
There are two methods: one is to make the toner itself magnetic (-component development method), and the other is to mix the toner with a carrier such as iron powder or ferrite powder (two-component development method).

For example, in a two-component development system, the developer is
The toner is made by kneading and pulverizing resins, coloring pigments, etc. and classifying them into particles of about 5 to 30 [μm], and a carrier such as iron powder, ferrite powder, nickel powder, etc. having a particle size of about 100 to 200 [μm]. ing. The toner and carrier constituting the two-component developer are triboelectrically charged to opposite polarities by mixing and stirring.

The amount of 417 heavy load on the toner at the time of this friction:;2 electric charge is approximately determined by 1) the friction between the toner and the carrier:1) the difference in the stain series, and 11) the electrical resistance of the toner or carrier. Controlling the amount of electricity 6+j is one of the most important things in the production of developer.

That is, in all developing methods, regardless of whether magnetic force is used or not, the amount of stains is controlled by: 1) image density I;
I) Fog 111) Toner scattering IV) Affects transfer efficiency, etc. This is because if 4irm is too low, the mirror image force that binds the carrier and toner becomes weak, increasing fog and causing toner scattering; If the value is too high, the mirror image force will be strong, resulting in a decrease in image density and a decrease in transfer efficiency.
It becomes 111.

Therefore, it is necessary to always adjust the toner's charge amount within a certain appropriate range;
In addition to being fluctuated at the start of i7D, it gradually changes as the image forming process is repeated. Further, the amount of charge on the toner changes sensitively to humidity, and in high humidity, the amount of charge on the toner decreases, making it easier for phenomena such as fogging and toner scattering to occur.

In order to keep the toner's 41) electrical charge stable and sufficient, the toner itself is usually improved. In other words, in order to control the amount of charge of the toner, it is necessary to improve the carrier.
However, the material of the carrier is relatively limited, the structure of the developing device is also limited, and the electrical resistance of the carrier is not predetermined in terms of image quality, especially gradation reproducibility. It is not considered common because it is easily exposed.

On the other hand, when improving the toner itself, for example, in the case of black monochrome toner, the following methods are generally known in order to control the amount of electrostatic charge of the toner. That is, in order to change the triboelectrification series of the toner, a certain amount of dye is added, and in order to adjust the electrical resistance of the toner by 2J, the amount of carbon black added is changed.

Therefore, in toner development, it is important to improve the dispersion state of charge control agents such as dyes or resistance adjusters (colorants) such as carbon black, and to ensure that each toner particle has a uniform composition. It becomes one of the most important elements in Moreover, if, for example, the charge control agent or resistance adjuster in the toner particles is poorly dispersed and a large amount of dye or carbon black stands out on the toner surface, these raised areas become moisture absorption points, causing the toner to absorb moisture. Moisture resistance will be impaired. Furthermore, if the floating dye or the like adheres to the carrier, it stains the surface of the carrier, changes the charging characteristics, accelerates the deterioration of the developer, and impairs its longevity. On the other hand, if we focus on a single toner particle, if the dispersion state of the charge control agent etc. is poor, the composition ratio of multiple raw materials in each particle will become uneven, and the distribution characteristics of the charge amount of the toner will become wide. Furthermore, the fluidity of the toner is reduced! 1, the image quality will deteriorate and the developer will deteriorate.

When producing such a toner by, for example, a mechanical pulverization method, the toner raw materials are dispersed during the mixing and kneading process. That is, using a kneading machine such as a pressurized kneader,
The binder resin, which is the main raw material, is heated and melted, and at the same time, coloring agents, etc. are uniformly dispersed by shearing force.

In this flooding/flooding process, factors that affect the dispersion state include material issues and kneading conditions. The size of becomes important. That is, the resin used as the binder is a thermosoluble resin X'h, and the viscosity decreases when the heating temperature is increased. For this reason, as a means of increasing dispersibility, conversely, the viscosity of the kneaded product is increased by lowering the heating temperature, and the shearing force is increased to make the dye and carbon black particles finer.

However, if a strong shearing force is simply applied to improve kneading properties, the resin molecules will be severed, resulting in deterioration of its properties, resulting in problems such as offset properties and deterioration of thermal properties such as storage stability. It ends up. Furthermore, if the temperature of the kneaded material decreases and the viscosity of the binder resin increases too much, the wettability of the dye or carbon black particles and the binder resin will deteriorate, and the binder resin and dye etc. will not come into close contact with each other, causing the space to increase. occur, etc.
The affinity between the binder resin and the dye etc. decreases.

Such toner also has the drawback that, after kneading, cooling, and pulverization, the dye and carbon particles tend to separate from the binder resin, resulting in a decrease in toner performance.

On the other hand, as another means to improve dispersibility, kneading 11
Create a kneaded product by increasing the length of '71pl or by increasing the concentration of the material you want to disperse, such as dye or carbon particles, in advance.
A method of forming this into a cloth is also known. As a specific example of the former, in a batch-type kneader such as a repressure kneader, the kneading time is extended to lli, whereas in a continuous-type kneader such as an extrusion kneader, the discharged material is cooled and coarsened. The most common method is to repeat kneading after crushing. However, both methods are suitable for manufacturing 11. However, there is a problem in that the amount of time required for production increases, leading to an increase in costs.

(Problem to be Solved by the Invention) Conventionally, as a means to improve the dispersibility of toner raw materials, which is one of the most important factors in toner production, studies have been conducted based on manufacturing conditions. It has been difficult to create a skewer that achieves sufficient dispersibility due to constraints from the balance with other factors and cost considerations.

In addition, even if we try to overcome these constraints and improve dispersibility, there is a limit if we only consider the manufacturing conditions, and due to the decrease in dispersibility, the moisture resistance of the toner may be impaired, the carrier may be stained, and the developer may be damaged. We are concerned about the deterioration of the Furthermore, due to the decrease in dispersibility, the composition ratio of the raw materials in the toner particles becomes non-uniform, which in turn widens the distribution characteristics of the charge amount and reduces fluidity, leading to a decrease in image quality, etc. This problem has been solved in that it is not possible to use a skewer to obtain toner with high image quality and long life.

Therefore, the present invention aims to eliminate the above-mentioned problems by improving the dispersibility of the current raw materials in toner particles, narrowing the distribution characteristics of the weight load, improving fluidity, and improving image quality. Further, it is an object of the present invention to provide a toner for image forming apparatuses which is excellent in moisture resistance and has a long service life.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention uses, as raw materials for toner, a material having a hydrogen ion concentration index of at least 4.0 or more.
:1) It uses an electric control component and a binder resin having an acidic group in its molecule.

(Sakukawa) The present invention improves the wettability between the charge control component of the toner and the binder resin by the means described in 2, prevents separation of raw materials during mixing and kneading, and incorporates each raw material into toner particles. Average
In addition, the skewer disperses in a state with good wettability, which improves image quality]
In addition to achieving the second goal, the life of the toner can be extended.

(Example) The toner according to the present invention uses, as raw materials, a charge control component having a hydrogen ion concentration index of pl+4.0 or more and a binder resin having an acidic group in the molecule. The pH value is 5 [g] of sample at 300 [α
1), add 100ml of ion-exchanged water, boil for 5 minutes, leave to cool, pour ion-exchanged water until it reaches its original volume, and filter with filter paper No. 2 manufactured by Toyo Roshi Co., Ltd. ,
This is the value measured for the a solution using a glass electrode pH meter. Further, the acidic group may be any arbitrary group such as a carboxyl group, a phenolic acidic group, or a sulfone group.

Then, when such a charge control component and a binder resin are mixed with carbon black or the like and kneaded in a kneader, the following phenomena occur and the raw materials are uniformly dispersed.

That is, as the temperature rises, the binder resin first dissolves. This solution has a p
l+4.0 or more ;) The electric control component acts as a base, generates a Coulomb force between the two, and the two are attracted to each other. In this way, the stain control component is uniformly dispersed in the binder resin with good wettability using the skewer that continues kneading the stain control component and the binder resin in a state with good adhesion. The Rukoto.

The present invention will be specifically explained below using Examples.

First, the method for producing the binder resin used in the examples will be described.

(Polymerization 1) Add isopropanol 1000 as a solvent to the fourth flask.
ml of azobisisobutyronitrile and 50 gl of azobisisobutyronitrile therein. Furthermore, styrene 1000 [gl.

Methyl acrylate 650 [gl, acrylic acid 3B [g
l, from one neck of the fourth flask,
It is added dropwise at such a rate that it takes [5 hours] from the start of dropping to the end of polymerization, and is polymerized by stirring while heating to 113[''C].The acid value of the styrenic copolymer obtained here is:
The result is 14.3 mg KOII/gl. However, this acid value is expressed in mgl of potassium hydroxide necessary to neutralize the acid contained in 1gl of resin.

(Polymerization 2) Isopropanol 1000 as a solvent in a four-loaf flask
ml of azobisisobutyronitrile and 50 gl of azobisisobutyronitrile therein. Furthermore, styrene 1000 [gl.

A mixture consisting of methyl acrylate G50 [gl, 1-sulfonine, and 4 vinylbenzene 92 [gl] was dropped at a constant dropping rate from one neck of a 11-mL flask.
The mixture is stirred while being heated to 3[° C.] and polymerized over 5 hours. The acid value of the styrenic copolymer obtained here was 0.
It was 9 [mg KOII/g].

(Polymerization 3) Add 1ooo of isopropanol as a solvent to the fourth flask.
[l11] and 50 [gl of azobisisobutyronitrile are added therein. Furthermore, styrene 1000 [gl.

Methyl acrylate) 050 [gl]
The styrenic copolymer obtained here is added dropwise at a constant rate from one neck of the flask, stirred and heated to 113 ["C], and polymerized for 5 [hours]. The acid value of the styrenic copolymer obtained here is , was 0.

Next, in the above (polymerization 1), r? A first embodiment will now be described in which a first toner is obtained using a binder resin prepared by the present invention.

Binder resin obtained in (Polymerization 1) 91.5 [Mold plate%]
Hymer 550P (polypropylene wax manufactured by Mitsubishi Kasei Corporation) 2 [wt%], HA-000 (carbon black manufactured by Mitsubishi Kasei Corporation) 5 [wt%], ; jj) Electric control component, hydrogen ion concentration index is pl + 7 , N of 9
-02 (Azine compound manufactured by Orient Chemical Co., Ltd.) 1.5
After mixing [wt%] respectively, kneading is carried out for 30 [minutes] at about 130 ['C] using a pressure kneader type kneader. Then, after cooling, it was crushed with a hammer mill, and then crushed with a ■ type jet mill = DS classifier (manufactured by NPK) to an average particle size of 12.0.
The first toner is obtained by finely pulverizing and classifying the toner so that it becomes [μIl]. Next, this first toner was mixed with P150 (ferrite carrier manufactured by Nippon Tetsuko Co., Ltd.) and a toner specific concentration of 40[
%] to prepare a first developer.

When the first toner thus obtained was observed using a microscope or the like, it was found that the electric control component 11 was well dispersed. Also, the Ai characteristics of the first toner IO are as shown by the solid line in FIG.
Shimi is sharp compared to someone who is 6'4 m. Furthermore, the fluidity of the first toner has been improved, and Toshiba's copier ReoDry BD-
2810, when toner was forcibly replenished for 60 [seconds] and the toner fell from the toner cartridge through a side window, it was found that the amount of the first toner was 2.1 [gl] compared to the conventional toner. Now, it has been doubled to 4.2 [g.

Furthermore, with Toshiba's ReoDry BD-2810 stepper camera,
When a paper passing test was conducted using the above first developer, [
As shown in Table 1], even after 200,000 sheets of paper were passed through the paper, there was no decrease in image density or fog, and high image quality was obtained.Furthermore, stains caused by toner scattering were also reduced. .

(The following is a blank space.) Next, the second to fifth embodiments will be described. In the second to fourth examples, the .:12 electric control component in the first example was replaced with N-09 (an azine compound manufactured by Orient Chemical Co., Ltd.) with a pI of +7.0 and N- with a pI of +5.7, respectively. 09 (Azine compound manufactured by Orient Chemical Co., Ltd.), pH
The other conditions were the same as in the first example, and the second to fourth toners and developers were This is what was created. On the other hand, the fifth embodiment
The binder resin in Example 2 was replaced with the binder resin obtained in (Polymerization 2), and the other conditions were the same as in Example 1 to prepare the fifth toner and developer. This is what I did.

In this way, the second
When the distribution characteristics of the 41-electrode charge amount and the fluidity of the fifth toner were determined at /111, good results were obtained in both cases as compared to the conventional toner, similar to the first toner. Furthermore, using the second to fifth developers, the Toshiba copier ReoDry BD-
When a paper passing test was conducted with 2810, as shown in Table 1, similar to the first developer, high image quality was obtained even after the paper passing test of 2810, and there was no staining due to toner scattering. was also reduced.

Next, a comparative example will be described. Here, in the first comparative example, the sixth toner and developer were created by replacing the binder resin in the first example with the binder resin with an acid value of 0 obtained in (polymerization 3). . The toner and developer were prepared under the same conditions as in the first example. When the distribution characteristics of the charge amount of the sixth toner thus obtained were measured, the distribution was wider than that of the toner shown in FIG. 1, as shown by the dotted chain line in FIG. In addition, regarding the fluidity of the toner, using a Toshiba Copying Machine RheoDry BD-2810, as in the case of the first toner,
When the falling amount was measured for 0 [seconds], it was 2.9 [gl], which was significantly reduced compared to the first toner.

Next, in a second comparative example, a seventh toner and developer was created by replacing the charge control component in the first example with N-05 (an azine compound manufactured by Orient Chemical Co., Ltd.) on page 113.3. be. The toner and developer were prepared under the same conditions as in the first example.

Similarly to the sixth toner according to the first comparative example, the seventh toner thus obtained was inferior to the first to fifth toners in charge distribution characteristics and fluidity. Furthermore, a paper passing test was conducted using the sixth and seventh developers using a Toshiba copying machine RheoDry BD-2810, and as shown in [Table 1], the sixth developer had a [Method]
The fog increased in the paper passing test of M7 developer, and the fog increased in the paper passing test of M7 developer. Furthermore, in both cases, the interior of the copying machine was significantly soiled due to toner scattering.

In this way, the hydrogen ion concentration index is pl as a charge control component.
+4.0 or higher azine compound and binder resin with acid value of 14.3 [mgK011/gl aluminum lt6.9]
In the toner of the above example obtained by mixing and kneading the styrene copolymer with carbon black and carbon black, the charge control component and the binder resin attract each other during mixing and kneading. The toner particles have good wettability, and each raw material is uniformly dispersed. Therefore, carbon black does not stand out on the toner surface and become a moisture absorption point or adhere to the carrier as in the conventional toner. In addition, a skewer with excellent moisture resistance, no loss of carrier, and a long lifespan of the developer can be produced. Historically, by dispersing the raw materials like food coloring, the composition ratio of the toner particles has become uniform, and compared to the conventional method, the tri-characteristics can be narrowed by the amount of charged electricity, improving fluidity.
From II to II, high image quality can be restored without any decrease in image density or fog. Furthermore, by reducing the staining inside the copying machine due to toner scattering, the life of the apparatus can be extended and maintainability can be improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments and can be modified in various ways. The binder resin also contains acidic groups in the molecule.
It's fine as long as it's something you do. That is, in addition to the azine compound, quaternary ammonium salts, chromium complex salt type azo dyes, etc. may be used as the 'jjF % controlling component. (uL, when a chromium complex type azo dye is used as a charge control component, it becomes negative polarity.

In addition, as the binder resin, styrenic copolymers such as polystyrene, styrene-butadiene copolymer, etc., including styrene-acrylic copolymer, polyethylene, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer can be used. So-called petroleum resins such as ethylene copolymers, phenolic resins, polyester resins, maleic acid resins, polymethyl methacrylate, polyacrylic acid, polyvinyl butyral, aliphatic or alicyclic hydrocarbon resins, aromatic hydrocarbons, etc. , chlorinated paraffin, low molecular weight polyethylene,
IT: Low molecular weight polypropylene, waxes, etc.

(More preferably, the binder resin is made of a polymer of a styrene monomer and an acrylic monomer).

In addition to styrene, styrene-based ill polymers include 1-sulfonyl, 4-vinylbenzene, and 1-sulfonyl having acidic groups.
- Hydroxine, 4-vinylbenzene, 1-carboxyl, 4-vinylbenzene The charge polarity of the toner is as follows, and all dielectric materials thereof are possible. In addition, as the acrylic monomer, acrylic acid esters such as acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, inbutyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, and octyl acrylate; Conventionally known acrylic acid and its dielectrics, such as methacrylic acid esters such as methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, inbutyl methacrylate, pentyl methacrylate, heptyl methacrylate, and octyl methacrylate; Acid and its dielectric material are optional.

Further, the carbon black used as a coloring agent can be either a furnace type or a channel type. Further, carbon black with large struts called conductive carbon may be used.

In addition, colorants other than carbon black include First Yellow G1 Benzine Yellow, Pigment Yellow, Indo First, Orange, Irgazine Red, Carmine FB, Permanent Bold FRR, Pigment Yellow.
Orange R1 Resole Red 2G, Lake Red C5
0-Damin FB10-Damin B Lake, Phthalocyanine Blue Pigment Blue, Brilliant Green B1
It is also possible to use phthalocyanine green, quinacridone, etc.

Further, the toner may be either a one-component toner or a two-component toner. However, in the case of a magnetic component toner, it is preferable that the magnetic powder used be an oxide of an element exhibiting ferromagnetism, such as iron, nickel, or cobalt, such as magnetite or ferrite.

On the other hand, wax may be added to the toner, if necessary, in order to improve offset resistance.

Furthermore, the apparatus for mixing and kneading a plurality of raw materials and the kneading conditions thereof are also optional as required.

[Effects of the Invention] As explained above, according to the present invention, due to the improved wettability between a plurality of raw materials, it takes a long time to manufacture as in the conventional method, and furthermore, it causes an increase in the number of manufacturing steps. To create a skewer that can easily obtain highly dispersible toner without increasing costs. Therefore, due to this improved dispersibility, the toner has better resistance to mixing than before, and in the case of a two-component developer, it does not cause staining of the carrier, and the life of the developer can be extended. Ill be able to do it. Furthermore, due to the improved dispersibility, the toner's charge amount distribution characteristics become narrower and its fluidity is improved. As a result, it is possible to obtain high-quality images without the need for skewers that cause a decrease in image density or fog, while also reducing toner scattering, preventing stains inside the image forming device, and extending the life of the device. , maintenance can be simplified.

[Brief explanation of drawings]

FIG. 1 is a graph comparing the spot distribution characteristics of the first toner of the present invention with the spot distribution characteristics of the conventional toner and the sixth toner.

Claims (1)

[Claims] As a raw material, the hydrogen ion concentration index is at least pH_4
．． A toner for an image forming apparatus, comprising a charge control component of 0 or more and a binder resin having an acidic group in its molecule.