JPH11167226A - Electrophotographic toner and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electrophotographic toners capable of providing color printed images which are good in image quality equivalent to that of silver salt photographs. SOLUTION: The toners are constituted to contain a binder resin and coloring agents. In such a case, the toners consist of tabular fine powder having an average diameter (dav ) within a range of 5 to 10 μm, an average thickness (wav ) within a range of 0.5 to 3 μm and a thickness/diameter ratio (dav /(wav ) within a range of 0.1 to 0.4. In addition, the toners are so formed that the status A density of the fixed toner images of respective colors when the toners are fixed onto a recording medium at a toner coating weight of 1 g/m<2> at the time of color printing is at least 1.2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner and a method for producing the same, and more particularly, to an electrophotographic color capable of providing a printed image having an image quality as excellent as a silver halide photograph. The present invention relates to a toner and a method for producing the same. The electrophotographic toner of the present invention can be used as a developer in various devices such as an electrophotographic copying machine, an electrophotographic printer, and an electrostatic printing machine, which can simultaneously print two or more colors by using an electrophotographic method. Can be used advantageously.

[0002]

2. Description of the Related Art Conventionally, electrophotography widely used in copiers, printers, printing presses, and the like generally employs a uniform static electricity on a photoconductive insulator such as a photosensitive drum. Providing a charge and irradiating the photoconductive insulator with a light image by various means to partially erase the electrostatic charge on the insulator to form an electrostatic latent image, and the remaining electrostatic charge Attach fine powder of developer called toner to the latent image part,
This is to visualize the latent image. The toner image obtained in this way is generally transferred to a recording medium such as recording paper and fixed to form a printed matter.

[0003] Toners conventionally used in electrophotography generally disperse a colorant, a charge control agent and the like in a binder resin made of a natural or synthetic polymer substance, and then pulverize the resulting dispersion. , Classify 8-12μm
It is formed into a spherical fine powder having an average particle diameter of the order. The toner fine powder is usually mixed with a carrier substance (carrier) such as iron powder or ferrite powder to form a developer,
It is subjected to a development step.

When printing is performed using such a conventional toner, since the fine toner powder has a spherical shape, printing is performed by sequentially overlapping toners of different colors, as in normal color printing. In this case, the layer thickness of the toner after fixing becomes as thick as about 20 μm, and a high-quality print such as a silver halide photograph having a smooth image surface cannot be obtained.

Japanese Patent Application Laid-Open No. 5-127420 discloses that a toner having a flat shape is used in order to reduce the layer thickness of the toner after fixing. The electrophotographic toner described in this publication is characterized in that the toner particles are flat particles having a diameter of 5 to 10 μm, and preferably, the thickness of the toner particles is 0.1 μm or more. The use of such a flat toner has the effects of improving the sharpness of an image and avoiding inconveniences such as background contamination. However, since the toner described in this publication is intended for monochrome printing in particular, it does not recognize the image quality in color printing, and in fact, in the conventional toner composition described in this publication, And the density of the color becomes low, so that a vivid color image as desired cannot be obtained.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrophotographic toner capable of providing a printed image having a quality as good as a silver halide photograph, particularly when used in color printing. It is in. It is another object of the present invention to provide a method for producing an electrophotographic toner as provided by the present invention.

[0007] Other objects of the present invention will be readily apparent from the following detailed description.

[0008]

According to one aspect of the present invention, there is provided an electrophotographic toner comprising a binder resin and a colorant, wherein the toner has an average diameter (d _av ) of 5 to 5.
10 μm range, average thickness (w _av ) in the range of 0.5 to 3 μm, and thickness / diameter ratio (w _av / d _av ) of 0.1 to
Status A density of a fixed toner image of each color when made of flat fine powder in the range of 0.4 and fixed on a recording medium with a toner adhesion amount of 1 g / m ² during color printing and fixed. Is at least 1.2.

According to another aspect of the present invention, there is provided an electrophotographic toner containing a binder resin and a colorant, the toner having an average diameter (d _av ) in the range of 5 to 10 μm and an average thickness (w _av ). It is composed of a flat fine powder having a range of 0.5 to 3 μm and a thickness / diameter ratio (w _av / d _av ) of 0.1 to 0.4, and 1 g / m ² at the time of color printing. In producing an electrophotographic toner having a status A density of at least 1.2 of a fixed toner image of each color when the toner is adhered on a recording medium with the amount of adhered toner and fixed,
A spherical toner elementary particle is prepared from the toner raw material containing the binder resin and the colorant, and the obtained toner elementary particle and a dispersion containing beads having a particle diameter of 2 mm or less are caused to collide with a rotating disk at a high speed. A method for producing a toner for electrophotography, characterized in that the elementary particles are pulverized and the fine particles of the flat toner are obtained at the same time.

According to the present invention, as described below, the toner for electrophotography is composed of fine powder having a specific shape and size, so that the thickness of the fixing toner layer on a recording medium such as paper can be reduced by the conventional method. By reducing the thickness from about 20 μm to 5 μm or less and realizing a high image density (status A density of at least 1.2) in such a thin layer thickness, a smooth printed image can be obtained, and the same level as a silver halide photograph can be obtained. This realizes high image quality.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrophotographic toner according to the present invention has a first feature in that fine powder having a specific shape and size is used. That is, the toner of the present invention has an average diameter (d _av ) of 5 to 10 μm, an average thickness (w _av ) of 0.5 to 3 μm, and a thickness / diameter ratio (w _av / d _av ). Is in the range of 0.1 to 0.4. In fact, when such an electrophotographic toner is used, even if toners of different colors are superimposed on recording paper or the like, the toner layer thickness is 5 μm at the maximum,
Usually, the thickness is significantly reduced to 1 to 3 μm, so that the thickness of the image does not increase even after the toner image is fixed, so that a smooth printed image can be obtained.

In order to reduce the thickness of the fixing toner layer, it is conceivable to use a spherical toner and reduce the toner particle size to about 2 to 3 μm instead of taking the shape of a flat fine powder as in the present invention. However, with such a fine spherical toner, if the toner is inhaled, there is a risk of suffering from diseases such as pneumoconiosis,
Not good for safety and health. In contrast, in the present invention,
By reducing the thickness of the toner layer only to a maximum of 5 μm, usually 1 to 3 μm, and setting the particle size of the toner to 5 μm or more, that is, by using a flat toner, without causing a problem in safety and health, The thickness of the fixing toner layer can be reduced.

Here, the particle diameter of the flat toner of the present invention is as follows:
There is no particular limitation as long as it is 5 μm or more. Even with such a flat or flat toner, if the particle size exceeds 10 μm, the developability decreases,
Faithful development cannot be performed, and the resolution decreases. Also,
If the toner particle size is less than 5 μm, as described above, it is not preferable in terms of safety and health. Therefore, in the toner of the present invention, the particle size of the fine powder (average diameter of the toner fine powder) is preferably in the range of 5 to 10 μm.

The average thickness of the toner fine powder is 0.5
It is preferably in the range of ３3 μm. When the average thickness is less than 0.5 μm, the toner is easily crushed, and fine powder toner is generated, and the scattering of toner and the generation of fogging (fouling of white paper by toner) increase. Conversely, if the average thickness of the toner fine powder exceeds 3 μm, it becomes difficult to develop the toner in a layered form during development, and it becomes impossible to develop a thin layer of toner. The average thickness of the toner fine powder is more preferably in the range of 0.5 to 3 μm.

Further, the ratio of the average thickness to the average diameter of the toner fine powder, that is, w _av / d _av is preferably 0.1 to
0.4. When the thickness / diameter ratio is less than 0.1, the toner is liable to be crushed, fine powder toner is generated, and scattering of the toner and generation of fog due to the toner (as described above) increase. . On the other hand, when the thickness / diameter ratio of the toner fine powder exceeds 0.4, it becomes difficult for the toner to be developed into a layer at the time of development, and it becomes difficult to develop a thin layer.

In the electrophotographic toner of the present invention, in addition to the first feature of using the fine powder having a specific shape and size as described above, the color density is high even when the toner layer thickness is small. That is, the second characteristic is that the status A density is at least 1.2. More specifically, in the toner of the present invention, during color printing,
It is necessary that the status A density of the fixed toner image of each color is at least 1.2 when the toner is deposited on the recording medium with a toner adhesion amount of 1 g / m ² and fixed. This is because when the toner is developed in a thin layer of about 1 to 3 μm, the amount of toner adhered on the recording medium is smaller than that of a conventional toner (5 to 10 m ² /
g), it is reduced to about 1/5 to 1/10, and in the conventional toner composition, the status A density of each color becomes lower,
This is derived from the findings of the present inventors that high image quality cannot be realized.

According to the present invention, by satisfying the first and second features, it is possible to realize a high quality image comparable to a silver halide photograph in a smooth printed image. Furthermore, in the electrophotographic toner of the present invention, the volume distribution of the toner is important. If the volume distribution of the toner is too wide,
Each toner has different chargeability,
Stable development cannot be performed. In the toner of the present invention, that is, in the flat toner fine powder,
It is preferable that at least 80% satisfy the condition of the following formula (I).

0.5d_av ^Two・ W_av <D^Two・ W <2d_av ^Two・ W_av ... (I) In the above equation, d_avAnd w_avAre the same as defined above
Where d is the major axis of the toner and w is the toner's
Thickness. Where d^Two・ The value of w is 0.5d _av ^Two・ W
_avBecomes less than or equal to the value of
Fog tends to occur, and on the contrary, 2d_av ^Two・ W
_avIs greater than or equal to the value of
The resolution of printing decreases.

Since the electrophotographic flat toner of the present invention is required to have high color developing properties, the colorant contained therein is a pigment, and its pigment concentration, that is, the content of the pigment in the toner, Preferably, the amount is in the high range of 10 to 30% by weight. By the way, when the pigment is dispersed in the toner as in the related art, if a high pigment concentration is adopted as in the present invention, the transparency of the toner is reduced due to the high pigment concentration, and the color printing becomes difficult. 2
When toners of colors or more are superimposed, a vivid image cannot be realized. Therefore, in the toner of the present invention,
In the pigment used, the adjustment is preferably performed so that the pigment particles having a particle diameter of 0.5 μm or more account for 10% by weight or less of the entire pigment. As described above, by suppressing the pigment particles having a particle size equal to or more than a predetermined level to a predetermined content or less, high transmittance can be obtained even at a high pigment concentration.

It has been found that the above-mentioned effects can be similarly obtained in a black toner, that is, when carbon or a similar black pigment is used as a colorant. In such a case, the content of carbon in the toner is in the range of 10 to 40% by weight, and
carbon particles having a particle size of at least 1 m
It is preferable to adjust so as to be 0% by weight or less.

The present inventors have further found that the viscoelasticity of the toner at 150 ° C. has a great effect in providing a smooth surface in the obtained fixed toner image in the state of thin layer development. The storage modulus at 150 ° C. was adjusted to the range of 500 to 50,000 dyn / cm ² , and the loss modulus was set to 1,000 to 100,000 dyn / cm ^2.
It has been found that a smooth image comparable to that of a silver halide photograph can be realized by adjusting the thickness to the range described above. Where 15
If the storage elastic modulus at 0 ° C. is less than 500 dyn / cm ² or the loss elastic modulus is less than 1000 dyn / cm ² , an offset occurs in the heat roll used for fixing the toner image, and conversely, the storage elastic modulus becomes lower. If it exceeds 50,000 dyn / cm ² or the loss elastic modulus exceeds 100,000 dyn / cm ² , a smooth image cannot be realized.

In addition, since the flat toner for electrophotography of the present invention does not have a spherical shape unlike the conventional toner, the fluidity of the toner tends to decrease. To avoid this, it is necessary to optimize the material to be externally added to the toner surface. As a result of intensive studies, the present inventors have found that it is preferable to add hydrophobic silica or titanium oxide as an external additive to a flat toner, particularly from the viewpoint of improving the fluidity. Are from 0.001 to 0.5 with respect to the average particle size of the primary particles.
It has been found that it is preferable to be in the range of μm. Further, according to the findings of the present inventors, in a flat fine powder of toner, the average particle diameter of the external additive adhered to the surface of the fine powder may be 0.5 μm or less. preferable. This is because the material used as the external additive in the present invention easily aggregates, but the effect of improving the fluidity is reduced when the aggregated particle diameter is large.

As described above, the electrophotographic toner of the present invention can be composed of a binder resin, a colorant and other additives such as a charge control agent and an external additive. The binder resin, which is a main component of the toner, generally includes various resin materials, but is preferably a resin material such as a polyester resin, a polystyrene resin, and a styrene-acryl copolymer resin.

The colorant to be dispersed in the binder resin includes many known pigments and can be arbitrarily selected and used. Suitable pigments include, for example, various carbon blacks such as black pigments (channel black, furnace black, etc.) and color pigments such as benzidine-based yellow pigments, quinacdrine-based, rhodamine-based magenta pigments, and phthalocyanine-based cyan pigments. Can be mentioned. These pigments may be used alone or may be used in combination to obtain a desired toner color.

The toner of the present invention may further have a charge control agent commonly used in this technical field for the purpose of controlling the charging characteristics of the toner. Suitable charge control agents include, for example, electronegative substances such as nigrosine dyes, fatty acid metal salts and quaternary ammonium salts for positively charged toners.
Examples of the negatively charged toner include an electron-accepting substance such as an azo metal-containing dye, chlorinated paraffin, and chlorinated polyester.

Further, when the toner image is fixed by a hot roll, various waxes such as low molecular weight polypropylene or polyethylene can be used as a releasing agent or an offset preventing agent. Further, as described above, for the purpose of improving the fluidity of the toner and for other purposes, it is preferable to use the hydrophobic silica or titanium oxide described above as an external additive. In the toner of the present invention, if necessary, in addition to hydrophobic silica or titanium oxide, other commonly used inorganic particles, resin particles, and the like may be further externally added.

The above-mentioned toner components can be used by changing the composition ratio thereof in a wide range according to the composition of conventional toners, except for the above-mentioned limitation on the content of the specific components. it can. For example, generally, 75 to 95% by weight of a binder resin, 1 to 10% by weight of a colorant, 0 to 5% by weight of a charge control agent, 0 to 5% by weight of a release agent, and 0 to 5% by weight of an external additive based on the total amount of toner. % By weight. These toner components may be more or less than the above ranges as needed.

The electrophotographic toner according to the present invention can be prepared according to various procedures using the above-mentioned toner components as starting materials. The toner of the present invention can be advantageously prepared by the following procedure, preferably according to a mechanical pulverization method. (1) Mixing of materials After measuring the binder resin, colorant, charge control agent, etc.,
Mix evenly with a powder mixer. As the powder mixer, for example, a ball mill or the like can be used. A colorant, a charge control agent, and the like are uniformly dispersed in the resin binder. (2) Melt kneading The obtained mixture is heated and melted, and further kneaded. A screw extruder (extruder), roll mill, kneader, or the like can be advantageously used. Fineness and uniform dispersion of the colorant particles are achieved. (3) Cooling and solidification After completion of kneading, the obtained kneaded material is cooled and solidified. (4) Pulverization First, the solidified kneaded material is coarsely pulverized by a coarse pulverizer such as a hammer mill and a cutter mill, and then finely pulverized by a fine pulverizer such as a jet mill. (5) Classification After the completion of the fine pulverization, the obtained finely pulverized particles are classified in order to remove fine particles which cause a decrease in toner fluidity, toner scattering and coarse particles which cause a deterioration in image quality. As a classifier, for example, an air classifier using centrifugal force can be used. Spherical toner particles are obtained. (6) Flattening Treatment Since the toner element particles after classification are spherical, they are flattened according to the present invention to obtain flat fine powder having a predetermined shape and dimensions. As a suitable flattening treatment, a dispersion liquid containing toner particles and beads having a particle diameter of 2 mm or less is made to collide with a rotating disk at a high speed to pulverize the toner particles and simultaneously remove the flat toner particles. The method of obtaining can be mentioned. The beads to be included together with the toner particles in the dispersion must not have a particle size greater than 2 mm in order to obtain a fine powder of the desired shape and size. As a suitable flattening apparatus, for example, a bead mill pulverizer can be used. The dispersion may contain water, a surfactant, and the like. Here, the rotating disk used has a rotation speed of about 2000 to 10000 and about 1 to 3
It is preferable to rotate with a rotation time of 0 minutes. (7) Surface treatment As a final step, hydrophobic silica or titanium oxide and other external additives as necessary are added to the surface of the obtained flat toner powder for the purpose of improving the fluidity of the toner and for other purposes. Add and adhere. As the device, for example, a high-speed flow mixer can be used.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to preferred embodiments. However, it should be understood that the invention is not limited to these examples. Example 1 In accordance with the present invention, black, yellow, magenta and cyan toners were prepared. Preparation of black toner: The following components were prepared in the stated ratios.

Binder resin: Linear polyester resin (softening point 110 ° C.) 77 parts by weight Coloring agent: Black Pearls L (trade name, manufactured by Cabot) 20 parts by weight Charge control agent: BONTRON E84 (trade name, manufactured by Orient Chemical Co., Ltd.) 1 part by weight Wax: Viscol 550-P (trade name, manufactured by Sanyo Chemical Co., Ltd.) 2 parts by weight These components were mixed and stirred by a ball mill, and then heated to 140 ° C.
The mixture was melt-kneaded with an extruder heated at a time. After the obtained kneaded material was cooled and solidified, it was coarsely pulverized by a pulverizer and further finely pulverized by a jet mill. The obtained fine powder was classified with an air classifier to obtain spherical toner elementary particles having an average particle size of 5 μm.

Subsequently, the spherical toner particles (100 g) obtained as described above were mixed with 5 kg of water and 5 g of a surfactant, and the resulting mixture was mixed with a bead mill pulverizer (bead particle size: 1 mm, From Simul Enterprise,
Product name: DYNO-MILL, commercially available as TypKDL)
And the mixture was caused to collide at a high speed against the rotating disk (rotation speed: 3000 rpm). After crushing for 10 minutes, the average diameter was 6 μm and the average thickness was 1 μm.
m in the form of a flat black toner powder. The storage elastic modulus at 150 ° C. of this toner fine powder is 2000 dyn / c.
m ² and the loss modulus were 3000 dyn / cm ² . Preparation of Yellow Toner: The following components were prepared in the stated ratios.

Binder resin: linear polyester resin (softening point: 110 ° C.) 82 parts by weight Colorant: benzimidazolone pigment, Pigment Yellow 154 15 parts by weight Charge control agent: BONTRON E84 (trade name, manufactured by Orient Chemical Co., Ltd.) Parts by weight Wax: Viscol 550-P (trade name, manufactured by Sanyo Kasei Co., Ltd.) 2 parts by weight These components were mixed and stirred by a ball mill, and then 140 ° C.
The mixture was melt-kneaded with an extruder heated at a time. After the obtained kneaded material was cooled and solidified, it was coarsely pulverized by a pulverizer and further finely pulverized by a jet mill. The obtained fine powder was classified with an air classifier to obtain spherical toner elementary particles having an average particle size of 5 μm.

Subsequently, the spherical toner elementary particles (100 g) obtained as described above were mixed with 5 kg of water and 5 g of a surfactant, and the resulting mixture was mixed with the same bead mill as used in the preparation of the black toner. The mixture was crushed at a high speed against the rotating disk (rotation speed: 3000 rpm). After grinding for 10 minutes,
A flat yellow toner fine powder having an average diameter of 6 μm and an average thickness of 1 μm was obtained. 150 ° C of this toner fine powder
Was 2000 dyn / cm ² , and the loss modulus was 3000 dyn / cm ² . Preparation of magenta toner: A magenta toner was prepared in the same manner as in the preparation of the yellow toner described above. In this example, instead of the benzimidazolone pigment, a quinacridone pigment, Pigment Red 122, was used in the same amount as the coloring agent. A flat magenta toner fine powder having an average diameter of 6 μm and an average thickness of 1 μm was obtained. The storage elastic modulus at 150 ° C. of this toner fine powder was 2,200 dyn / cm ² , and the loss elastic modulus was 3,100 dyn / cm ² . Preparation of cyan toner: A cyan toner was prepared in the same manner as in the preparation of the yellow toner described above. In this example, a copper phthalocyanine pigment, Pigment Blue 15 was used in the same amount as the coloring agent instead of the benzimidazolone pigment. A fine powder of a flat cyan toner having an average diameter of 6 μm and an average thickness of 1 μm was obtained. The storage elastic modulus at 150 ° C. of this toner fine powder was 2,100 dyn / cm ² , and the loss elastic modulus was 3,300 dyn / cm ² . Example 2 A full-color printing test was performed using the four color toners (black, yellow, magenta, and cyan) prepared in Example 1 above. The configuration of the multicolor image forming apparatus used in the printing test in this example is shown in FIG. That is, in FIG. 1, the multicolor image forming apparatus 10 has a paper feeding unit, a charging unit, an exposing unit, a developing unit, a transfer unit, a fixing unit, a paper discharging unit, and the like as shown in the drawing. I have. The drum-shaped photoconductor 1 is rotated in the direction of the arrow.
The surface is uniformly charged by the charger 2 of the charging section. Next, in the exposure section, image light is projected on the surface of the photoconductor 1 charged in the previous step in accordance with the recorded information, and an electrostatic latent image is formed. When the photoconductor 1 further rotates and reaches the developing unit, the electrostatic latent image on the surface of the photoconductor 1 is developed with toner (developer) by the developing unit 3 and is visualized. The multi-color image forming apparatus uses four types of toners, black B, magenta M, cyan C, and yellow Y.
The toner is supplied to the developing device 3 via the toner hopper 4. Subsequently, transfer of the developed toner image to paper and fixing are performed. In the illustrated example, the developed toner image is transferred onto a sheet (not shown) on the sheet conveying belt 5 by a transfer roller 6 that is movable on the sheet conveying belt 5 and is in contact with each photoconductor 1. The images are sequentially transferred. In this case, the mechanism of image transfer is to apply a charge of a polarity opposite to the toner charging direction to the developed toner image on the photoreceptor 1 from the back of the paper. After completion of the image transfer, a pair of heat rolls 7 of the fixing unit (surface temperature: 1)
70 ° C.) to fix the transferred toner image. In this fixing step, the multicolor toner image transferred onto the paper is heated by a heat roll, so that the multicolor toner image can be fixed on the paper with a non-peelable strength. The non-transferred toner remaining on the surface of the photoconductor 1 in the previous transfer step can be removed by the cleaning unit 8 and returned to the developing unit again. Finally, the sheet having the fixed toner image is guided to the stocker 9 via the sheet discharging system.

For each of the four types of color toners prepared in Example 1, 0.5% by weight of hydrophobic silica, R
972 (trade name, average particle size of primary particles: 0.03 μm,
(Nippon Aerosil Co., Ltd.). On the surface of the toner, the average particle diameter of the externally added hydrophobic silica adhered to the toner is 0.1.
It was 1 μm. Next, the toner was charged with an average diameter of
m was mixed with a resin-coated ferrite carrier to prepare a developer having a toner concentration of 5% by weight. The obtained developer is mounted on the above-described multicolor image forming apparatus, and the following items (1) to (1)
For (5), a full-color printing test was performed. In each of the developers, the charge amount on the surface of the drum-shaped photoreceptor was about −20 μC / g, and the fixing temperature (surface temperature of the heat roll) was 170 ° C. (1) Status A density The status A density of the fixed toner image when printing was performed with a toner adhesion amount of 1 g / m ² was measured with a Macbeth densitometer.
The following satisfactory results were obtained.

Yellow image: 1.25 Magenta image: 1.22 Cyan image: 1.26 Black image: 1.27 (2) Image quality The layer thickness of the fixed toner image can be reduced to 3 μm or less, and high smoothness can be obtained. I realized it. High image quality comparable to silver halide photography was obtained. (3) Scattering of Toner Scattering of toner due to charging failure did not occur, and toner contamination in the apparatus could be prevented. (4) Generation of fog At the time of development, generation of fog due to poor charging could not be observed. (5) Fluidity of Toner The fluidity of the toner was excellent, and thus the toner could be smoothly supplied in the apparatus.

It is understood from the results of the above-described printing test.
In the case of the electrophotographic toner of the present invention,
When used for full-color printing, high image quality comparable to silver halide photography
Can provide a simple printed image,
To prevent toner contamination and fogging inside the printer,
Replenishment of the nut can be performed smoothly.Example 3 The method described in the above Examples 1 and 2 was repeated.
If the average diameter of each used toner is 6 μm,
Was changed to 5 μm. Full color printing test results
The results of Example 2 were satisfactory and comparable.Example 4 The method described in the above Examples 1 and 2 was repeated.
If the average diameter of each used toner is 6 μm,
Was changed to 10 μm. The result of the full color printing test is
The results were satisfactory, comparable to the results of Example 2.Example 5 The method described in the above Examples 1 and 2 was repeated.
If the average thickness of each toner used is 1 μm
Was changed to 0.5 μm. Full color printing test results
Is satisfactory, comparable to the results of Example 2 above.
Was.Example 6 The method described in the above Examples 1 and 2 was repeated.
If the average diameter of each used toner is 6 μm,
To 8 μm and the average thickness from 1 μm to 3 μm.
I changed it. The results of the full-color printing test are the results of Example 2 above.
It was satisfactory and comparable.Example 7 The method described in the above Examples 1 and 2 was repeated.
If the average diameter of each used toner is 6 μm,
To 5 μm and the average thickness from 1 μm to 0.5 μm
Changed to The result of the full-color printing test was
The results were satisfactory and comparable.Example 8 The method described in the above Examples 1 and 2 was repeated.
If the average diameter of each used toner is 6 μm,
To 5 μm and the average thickness from 1 μm to 2 μm.
I changed it. The results of the full-color printing test are the results of Example 2 above.
It was satisfactory and comparable.Example 9 The method described in the above Examples 1 and 2 was repeated.
In the case, regarding the particle size distribution of each used toner,
Formula: 0.5d_av ^Two・ W_av <D^Two・ W <2d_av ^Two・
w_av(Where d is_av, W_av, D and w are, respectively,
80% of toners satisfy the same definition)
The major axis and thickness of the toner were adjusted as described. Full color
-The results of the printing test are satisfactory, comparable to the results of Example 2 above.
Could be done.Example 10 The method described in the above Examples 1 and 2 was repeated.
When preparing each used toner, black toner
Carbon content from 20% by weight to 10% by weight
And yellow, magenta and cyan toners in toner
The pigment content from 15% by weight to 10% by weight
Was. The result of the full-color printing test was 1. for each color toner.
A status A density of 2 or more is realized, and
Comparable and satisfactory.Example 11 The method described in the above Examples 1 and 2 was repeated.
When preparing each used toner, black toner
Carbon content from 20% by weight to 40% by weight
And yellow, magenta and cyan toners in toner
The pigment content was changed from 15% by weight to 30% by weight
Was. The result of the full-color printing test was 1. for each color toner.
A status A density of 3 or more is realized, and
Comparable and satisfactory.Example 12 The method described in the above Examples 1 and 2 was repeated.
When preparing each used toner, the binder tree
Epo from a linear polyester resin (softening point 110 ° C)
Toxic resin (softening point 100 ° C)
The storage elastic modulus of the fine powder at 150 ° C is 500 dyn / c
m^Two, Loss modulus is 1000dyn / cm^TwoAdjusted to be
did. The result of the full-color printing test is the same as the result of Example 2 above.
Comparable and satisfactory.Example 13 The method described in the above Examples 1 and 2 was repeated.
When preparing each used toner, the binder tree
Fat is branched from linear polyester resin (softening point 110 ℃)
Type polyester resin (softening point 130 ° C)
The storage elastic modulus at 150 ° C. of the toner
000dyn / cm^Two, Loss modulus is 100,000 dyn / cm^TwoWhen
It was adjusted to become. Full color printing test results
The results of Example 2 were satisfactory and comparable.Example 14 The method described in the above Examples 1 and 2 was repeated.
When preparing each developer used, use it as an external additive.
Same amount of hydrophobic silica, R972 (trade name, primary particle
Average particle size: 0.001 μm, manufactured by Nippon Aerosil Co., Ltd.)
Added. Externally attached hydrophobic particles attached to the toner surface
The average particle size of the functional silica was 0.05 μm. Full color
-The results of the printing test are satisfactory, comparable to the results of Example 2 above.
Could be done.Example 15 The method described in the above Examples 1 and 2 was repeated.
When preparing each developer used, use it as an external additive.
Same amount of hydrophobic silica, R972 (trade name, primary particle
Average particle size: 0.5 μm, manufactured by Nippon Aerosil Co., Ltd.)
Was. On the toner surface, the externally added hydrophobic particles
The average particle size of Rica was 0.5 μm. Full color printing
The results of the test are satisfactory, comparable to the results of Example 2 above
Was something.Example 16 The method described in the above Examples 1 and 2 was repeated.
When preparing each developer used, use it as an external additive.
The same amount of titanium oxide, STT-
30A (trade name, average particle size of primary particles: 0.001μ)
m, manufactured by Titanium Industry Co., Ltd.). Smell on toner surface
The average particle size of the externally added titanium oxide attached to the
It was 5 μm. The results of the full-color printing test are shown in the above examples.
The results were satisfactory, comparable to the results of Example 2.Example 17 The method described in the above Examples 1 and 2 was repeated.
When preparing each developer used, use it as an external additive.
And replace the hydrophobic silica with the same amount of titanium oxide (primary particles
Average particle size: 0.5 μm, prototype). toner
On the surface, the average grain of externally added titanium oxide attached to it
The diameter was 0.5 μm. Full color printing test results
Is satisfactory, comparable to the results of Example 2 above.
Was.Example 18 The method described in the above Examples 1 and 2 was repeated.
When preparing each used toner, bead mill
The particle size of the beads of the crusher was changed from 1 mm to 2 mm. average
Flat toner fine powder with a diameter of 8 μm and an average thickness of 2 μm
was gotten. The result of the full-color printing test is
The results were satisfactory and comparable.Comparative Example 1 The method described in the above Examples 1 and 2 was repeated.
For comparison, the average direct
The diameter was changed from 6 μm to 4 μm. Full color printing test
The toner is crushed in the developing unit and
And fogging and toner scattering occurred.Comparative Example 2 The method described in the above Examples 1 and 2 was repeated.
For comparison, the average direct
The diameter was changed from 6 μm to 12 μm. Full color printing trial
The resolution was reduced and good image quality was not obtained.
Was not.Comparative Example 3 The method described in the above Examples 1 and 2 was repeated.
The average thickness of each toner used for comparison.
The length was changed from 1 μm to 0.3 μm. Full color printing
As a result of the test, the toner was crushed in the developing unit and
Fine toner increased, and fogging and toner scattering occurred.Comparative Example 4 The method described in the above Examples 1 and 2 was repeated.
For comparison, the average direct
Change the diameter from 6μm to 8μm and make the average thickness 1μm
Was changed to 4 μm. Full color printing test
Of course, a smooth image could not be realized.Comparative Example 5 The method described in the above Examples 1 and 2 was repeated.
For comparison, the average direct
Change the diameter from 6μm to 8μm and make the average thickness 1μm
Was changed to 0.5 μm (w_av/ D_av= 0.063).
When a full-color printing test was performed, the toner
Is crushed, fine toner increases, fog and toner scatter
There has occurred.Comparative Example 6 The method described in the above Examples 1 and 2 was repeated.
For comparison, the average direct
Change the diameter from 6μm to 5μm and make the average thickness 1μm
Changed to 3 μm (w_av/ D_av= 0.6). Full color
ー Is it possible to realize a smooth image after performing a printing test?
Was.Comparative Example 7 The method described in the above Examples 1 and 2 was repeated.
In this case, for comparison, the particle size of each toner used was
For cloth, the formula: 0.5d_av ^Two・ W_av <D ^Two・ W
<2d_av ^Two・ W_av(Where d is_av, W_av, D and w are
Each of which is the same as defined above)
Adjust the major axis and thickness of toner so that toner is 70%
did. When a full-color printing test was performed,
Below was observed.Comparative Example 8 The method described in the above Examples 1 and 2 was repeated.
Preparation of each toner used, if any, for comparison
When the content of carbon in the black toner is reduced from 20% by weight
8% by weight and yellow, magenta and cyanite
15% to 8% by weight of pigment in the toner
Changed to After performing a full-color printing test, each color
Status A density of 1.2 or more can be achieved with toner
The image was also low in saturation and not vivid.Comparative Example 9 The method described in the above Examples 1 and 2 was repeated.
Preparation of each toner used, if any, for comparison
When the content of carbon in the black toner is reduced from 20% by weight
50% by weight and yellow, magenta and cyan
Toner The content of the pigment in the toner is from 15% by weight to 40% by weight.
The amount was changed to%. After performing a full-color printing test,
Realization of status A density of 1.3 or more for each color toner
However, the transparency decreased and the toner was superimposed.
At that time, the saturation was low, and a vivid image could not be realized.Comparative Example 10 The method described in the above Examples 1 and 2 was repeated.
Preparation of each toner used, if any, for comparison
When the binder resin is a linear polyester resin (softening point 11
0 ° C) to polyester resin (softening point 95 ° C)
And storage elasticity of the resulting toner fine powder at 150 ° C
Rate is 400dyn / cm^Two, Loss modulus is 800dyn / cm^TwoTona
Was adjusted to Full color printing test
Also, an offset to the hot roll occurred, and the image was disturbed.Comparative Example 11 The method described in the above Examples 1 and 2 was repeated.
Preparation of each toner used, if any, for comparison
When the binder resin is a linear polyester resin (softening point 11
0 ° C) to cross-linked polyester resin (softening point 135 ° C)
And store the obtained toner fine powder at 150 ° C.
Storage modulus is 70000 dyn / cm^Two, Loss modulus is 2000
00dyn / cm^TwoIt was adjusted to be. Full color printing trial
As a result, smooth images could not be realized.Comparative Example 12 The method described in the above Examples 1 and 2 was repeated.
In each case, the preparation of each developer used for comparison
At the same time, the same amount of hydrophobic silica as an external additive, R972 (product
Name, average particle size of primary particles: 0.0008 μm,
Rosil). On the toner surface,
The average particle diameter of the attached externally added hydrophobic silica is 0.05 μm.
there were. When a full-color printing test was performed, the toner
Toner scattering occurred due to poor charging.Comparative Example 13 The method described in the above Examples 1 and 2 was repeated.
In each case, the preparation of each developer used for comparison
At the same time, the same amount of hydrophobic silica as an external additive, R972 (product
Name, average particle size of primary particles: 0.7 μm, Nippon Aerosil
Was added. Adheres to it on the toner surface
The average particle size of the externally added hydrophobic silica was 1.5 μm.
When a full-color printing test was performed, the fluidity of the toner was
It is not possible to supply toner smoothly,
Degraded and distorted image.Comparative Example 14 The method described in the above Examples 1 and 2 was repeated.
In each case, the preparation of each developer used for comparison
At the same time, the same amount of oxide
Tan (average particle size of primary particles: 0.0008 μm, prototype)
Product) was added. On the toner surface
The average particle size of the externally added titanium oxide was 0.05 μm. H
Color printing test, the toner charging failure
Caused toner scattering.Comparative Example 15 The method described in the above Examples 1 and 2 was repeated.
In each case, the preparation of each developer used for comparison
At the same time, the same amount of titanium oxide was used as an external additive instead of hydrophobic silica.
Add tan (average primary particle size: 0.7 μm, prototype)
Added. External oxidation attached to the toner surface
The average particle size of titanium was 1.5 μm. Full color stamp
Character test showed that the fluidity of the toner was
The toner cannot be replenished, the toner density decreases,
Was disturbed.Comparative Example 16 The method described in the above Examples 1 and 2 was repeated.
Preparation of each toner used, if any, for comparison
At the time, the particle size of the beads of the bead mill crusher was changed from 1 mm to 3 mm
changed. A flat plate with an average diameter of 8 μm and an average thickness of 4 μm
A fine toner powder was obtained. Perform full color printing test
However, due to the increase in the average thickness of the toner fine powder,
Smooth images could not be realized.

[0037]

As described above, according to the present invention, it is possible to obtain an electrophotographic toner capable of providing a printed image as high in quality as a silver halide photograph when used for color printing. Further, according to the present invention, such an excellent electrophotographic toner can be manufactured with a high yield by a simple method.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of a multicolor image forming apparatus using an electrophotographic toner of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Photoreceptor 2 ... Charging device 3 ... Developing device 4 ... Toner hopper 5 ... Paper conveyance belt 6 ... Transfer roller 7 ... Heat roll 8 ... Cleaning part 9 ... Stocker 10 ... Multicolor image forming apparatus

Claims (2)

[Claims] 1. An electrophotographic toner comprising a binder resin and a colorant, wherein the toner has an average diameter (d _av ) of 5 to 10 μm and an average thickness (w _av ) of 0.5 to 3 μm. And a thickness / diameter ratio (w _av / d _av ) of 0.1 to 0.4 in the range of 0.1 to 0.4, and 1 g /
A toner for electrophotography, wherein a status A density of a fixed toner image of each color when applied and fixed on a recording medium with a toner adhesion amount of m ² is at least 1.2. 2. An electrophotographic toner comprising a binder resin and a colorant, wherein the average diameter (d _av ) is in the range of 5 to 10 μm, the average thickness (w _av ) is in the range of 0.5 to 3 μm, and It is made of a fine plate-like powder having a thickness / diameter ratio (w _av / d _av ) in the range of 0.1 to 0.4, and has a value of 1 in color printing.
g / m ² of toner adhered onto a recording medium and fixed to form an electrophotographic toner having a fixed toner image of each color having a status A density of at least 1.2, And preparing a spherical toner elementary particle from a toner raw material containing a colorant and a dispersion liquid containing the obtained toner elementary particle and beads having a particle diameter of 2 mm or less at a high speed against a rotating disk to produce the toner. A method for producing a toner for electrophotography, comprising: pulverizing elementary particles and obtaining the above-mentioned flat toner fine powder at the same time.