JP2001330996A - Method for image formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for image formation such that a photoreceptor drum is prevented from scraping although a photoreceptor having a thin photosensitive layer is used and that high-definition picture quality can be stably obtained even after the photoreceptor is repeatedly used. SOLUTION: The method includes an exposure process to irradiate the electrophotographic photoreceptor with light by using two-component developer containing a magnetic carrier and a toner. The magnetic carrier used has 5 to 100 μm number average particle size, <=20 number % cumulative value in the distribution for the particle size as <=1/2 as the number average particle size, and 1.01 to 1.4 SF-1 (shape factor) and 1.1 to 2.5 SF-2. The toner used has 1 to 10 m weight average particle size, <=20 number % cumulative value in the distribution for the particle size as <=1/2 as the number average particle size, <=10 wt.% cumulative value in the distribution for the particle size as >=2 times as the weight average particle size, and 1.0 to 1.4 SF-1 and 1.1 to 2.5 SF-2. The toner has a coating layer formed by deposition of granular aggregates containing at least a silicon compound on the surface of toner particles. The product of the spot area of the light in the exposure process and the thickness of the photosensitive layer of the photoreceptor ranges from 1,000 to 20,000 μm3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an electrophotographic photosensitive member and at least a two-component developer which can be widely used in copiers, printers, facsimile machines, plate making systems and the like using an electrophotographic system. The present invention relates to an image forming method.

[0002]

2. Description of the Related Art Heretofore, electrophotography has been described in U.S. Pat.
No. 0 and Japanese Patent Publication No. 43-24748 describe various methods. All of these methods form an electrostatic latent image by irradiating a photoconductive layer with a light image corresponding to a document, and then call a toner having the opposite polarity on the electrostatic latent image. The electrostatic latent image is developed by applying colored fine powder, and a toner image is transferred to a transfer material such as paper as necessary, and then fixed by heat, pressure, or solvent vapor to obtain a copy or printout. Things.

The step of developing the electrostatic latent image includes forming an image of the charged toner particles on the electrostatic latent image on the latent image carrier by utilizing the electrostatic interaction of the electrostatic latent image. It is. In general, among the methods for developing such an electrostatic latent image using toner, a two-component developer in which the toner is dispersed in a medium called a carrier is particularly suitable for a full-color copying machine and a full-color printer that require high image quality. It is used for
Then, in order to enable formation of more precise and high-quality images, proposals have been made for optimizing the particle diameter of particles constituting the toner and the carrier.

[0004] For example, as means for facilitating control of the particle diameter of toner and carrier, Japanese Patent Application Laid-Open No. 59-34583 and Japanese Patent Application Laid-Open No. 2-22006 disclose a carrier.
No. 8 has proposed a production method by a polymerization method.
Regarding the toner, JP-A-36-10231, JP-A-43-10799, and JP-A-51-148.
No. 95 discloses a production method by a polymerization method.

Since the toner particles and carrier particles obtained by the above-mentioned polymerization method are spherical,
Compared to a developer composed of amorphous particles obtained by a conventional pulverization method, the developer has much better fluidity and developability, and also achieves high transfer efficiency. However,
In a two-component developer using spherical toner particles having a smooth surface and carrier particles having a smooth surface, the slipperiness of each other and the contact probability between the toner and the carrier are reduced. There is a drawback that the triboelectric charging property is inferior, the rise of the triboelectric charge is slow, and the image characteristics are impaired.

To solve this problem, Japanese Patent Laid-Open Publication No. 1-1
No. 85653 proposes to increase the contact probability between the toner particles and the carrier particles by forming the developer inferior in sphericity to the spherical toner particles, that is, by combining the non-spherical carrier particles. Have been. However, when a non-spherical carrier having poor sphericity is used, the fluidity of the developer constituted by the non-spherical carrier is deteriorated, and the high fluidity, which is one of the effects of the spherical toner, is not exhibited. There is a disadvantage that. Also, in the case of using toner particles that are spherical and have a very smooth surface, even if the contact probability between the toner particles and the carrier particles is increased by improving the shape of the carrier, sufficient triboelectrification and stable characteristics are obtained. No triboelectric charge is obtained. In particular, this tendency is remarkable when used in a high-speed electrophotographic machine.

Here, a conventional image quality forming method will be described. At present, a typical latent image forming method used in laser printers and the like is a binary recording method of forming an image such as a character or a line figure by irradiating a photoreceptor with a laser beam or not. is there. In general, printing of characters, line figures, and the like does not require halftones, so that the structure of the printer can be simplified.

However, in recent years, with the development of multimedia, computer image processing, and the like, means for outputting high-definition and high-gradation images has been demanded. There are printers that can express halftones even with the binary recording method described above. As such a printer, a printer employing a dither method, a density pattern method, or the like is well known. However, as is well known, high resolution cannot be obtained with a printer employing a dither method, a density pattern method, or the like. Therefore, a method (PWM method) of forming a halftone in each pixel with high resolution without reducing the recording density has been proposed. In this method, a halftone pixel is formed by modulating the time of irradiating a laser beam with an image signal. According to this method, a high-resolution and high-gradation image can be formed. Therefore, the PWM method is particularly suitable for a color image forming apparatus requiring high resolution and high gradation.
That is, according to this method, since the area gradation of the dot formed by the beam spot can be performed for each pixel, a halftone can be expressed without lowering the resolution.

However, even in this PWM method, if the pixel density is further increased, the pixels become relatively small with respect to the exposure spot diameter, so that the gradation by the exposure time modulation cannot be sufficiently obtained. There is. Therefore, in order to improve the resolution while maintaining the gradation, it is necessary to make the exposure spot diameter smaller. For this purpose, for example, when using a scanning optical system using a laser, to shorten the wavelength of the laser light,
It is necessary to increase the NA of the f-θ lens.
However, if such a method is used, the use of expensive lasers, the enlargement of lenses and scanners, the increase in mechanical accuracy required due to the decrease in the depth of focus, and the like make it inevitable to increase the size and cost of the apparatus. Further, even in a solid-state scanner such as an LED array or a liquid crystal shutter array, an increase in the price of the scanner itself, an increase in mounting accuracy, and an increase in the cost of the electric drive circuit are inevitable. Further, as described above, it is difficult to obtain good tone reproducibility in the electrophotographic system even when the light spot is miniaturized. Conventionally, the tone is simulated by electrical processing. It was just reproducing.

[0010] In spite of the above-mentioned problems, the resolution and gradation required of an image forming apparatus using an electrophotographic system have been increasing more and more in recent years. Under such circumstances, attempts have been made to improve the resolution and gradation by reducing the particle size of the toner used for development, and to improve the uniformity of the development conditions. However, even if such improvements are made, the reproducibility of gradation data such as full-color image data of 256 gradations of 400 to 600 lines recognizable by the naked eye and the high-resolution reproduction of binary images such as characters. Was not enough.

For such a situation, Japanese Patent Laid-Open No.
No. 9454 or Japanese Patent Application Laid-Open No. 1-172863 discloses a photoreceptor having such a characteristic that the sensitivity is small at a low exposure amount and the sensitivity increases as the exposure amount increases. It has been found that the same effect as that of reducing the irradiation spot diameter by removing the low exposure portion of the irradiation spot having the intensity distribution can be obtained. As a result, in an image forming apparatus that scans an irradiation spot having an intensity distribution with respect to such a photoreceptor, it has become possible to stably obtain a high resolution equal to or smaller than the irradiation spot diameter. However, even when such a photosensitive member is used, it has been difficult to stably reproduce 256 gradations using a 400 dpi PWM.

To solve the above problem, Japanese Patent Laid-Open No. 8-272
Japanese Patent Application Laid-Open No. 197/1973 discloses an electrophotographic image forming apparatus that forms a latent image by irradiating a light beam with a product of the thickness of the photoconductive layer of the photoconductor and the irradiation spot area of 20,000 μm ^3.
By the following, the phenomenon that the image information given by the light spot is deteriorated because the optical carrier for forming the latent image is diffused while traveling through the photoconductive layer, There has been proposed a method for stably forming a fine latent image by preventing a phenomenon that a potential potential contrast caused by a latent image is reduced by a space existing up to a conductive substrate.

On the other hand, in order to obtain a high-resolution image output,
In the developing step, a so-called two-component developer using a magnetic carrier and a toner is generally used. However, even if the photoreceptor is improved as described above, it is difficult to develop a fine latent image as described above with good reproducibility as long as a conventional developer is used.

Here, the film thickness of the photoconductive layer and the irradiation
The product of the pot area is 20,000μm ^ThreeLike
The photoreceptor has a high resolution of 400 dpi or more.
If it is used, is it substantially less than 20 μm?
It means a photoreceptor having a thin photoconductive layer. Against this
When the electrophotographic machine is running,
The surface is repeatedly rubbed by the cleaning process and the developing process.
May be worn. Especially for toner components
When drum scraping occurs due to the effect of external additives
was there. This problem is thinner than before
It becomes more noticeable in the photoconductor having a photoconductive layer,
Sometimes when adverse effects such as black spots appear on the image
There was a match.

[0015]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a drum having a thin photosensitive layer capable of providing a higher definition image and, in particular, a high definition image in order to achieve high durability of the photosensitive member. An object of the present invention is to provide an image forming method which can prevent drum abrasion despite being used and can stably provide sufficiently high-definition image quality even after printing a large number of sheets.

[0016]

The above objects can be achieved by the present invention described below. That is, the present invention provides a developing step using a two-component developer having at least a magnetic carrier and a toner, and a charging step of charging an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support. In an image forming method having an exposure step of irradiating a charged electrophotographic photosensitive member with light, the magnetic carrier has a number average particle size of 5 to 100 μm in a particle size distribution, and is 1/1/1 of the number average particle size. Distribution cumulative value of 2 times or less is 2
0% by number or less, and the carrier shape factor SF−
1 is in the range of 1.0 to 1.4, and the shape factor SF-2
Is in the range of 1.1 to 2.5, and the toner has a weight average particle diameter of 1 to 10 μm in the particle size distribution.
m, the cumulative distribution value of less than half the diameter of the number average particle size (D ₁ ) is 20% by number or less, and the cumulative distribution value of the double diameter of the weight average particle size (D ₄ ) is 10% or less. % By weight or less, the shape factor SF-1 of the toner is in the range of 1.0 to 1.4, and the shape factor SF-2 is in the range of 1.1 to 2.5. On the surface of the toner particles constituting the toner, there is provided a coating layer formed by fixing granular souls containing at least a silicon compound. In the above-mentioned exposure step, the spot area of the irradiated light and the conductivity The product of the thicknesses of the photosensitive layers on the support is 1,000
20,000 μm ³ to 20,000 μm ³ .

The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, have developed a developing process using a two-component developer composed of a toner and a magnetic carrier, and a photosensitive layer on a conductive support. A charging step of charging the electrophotographic photoreceptor having: and an exposure step of irradiating the charged electrophotographic photoreceptor with light. When the photosensitive layer having a product of the thickness of the photoconductive layer and the irradiation spot area of 20,000 μm ³ or less uses a substantially thin photoconductor, if the configuration of the two-component developer is specified, 400 dpi P
256 gradation reproduction by WM is performed stably, and the photosensitive drum is effectively prevented from being scraped, and even in durability, image formation with high transfer efficiency can be realized without causing image defects such as black spots. This led to the present invention.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. First, the image forming method according to the present invention comprises, after a charging step of charging an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support, exposing the charged electrophotographic photosensitive member to light. The process is characterized in that the product of the spot area of the irradiated light and the thickness of the photosensitive layer on the conductive support is 1,000 to 20,000 μm ³ . That is, as described above, if the product of the thickness of the photosensitive layer of the photoreceptor and the irradiation spot area is controlled to be 20,000 μm ³ or less, the photocarriers for forming the latent image can form the photoconductive layer. The phenomenon that the image information given by the light spot is degraded due to diffusion during traveling, and the potential potential contrast generated by the formed latent image is reduced by the space existing up to the conductive substrate. The phenomenon can be prevented.

For this purpose, it is required to reduce the diameter of the light irradiation spot in the exposure step or to reduce the thickness of the photosensitive layer. As described above, an increase in the size of the apparatus and an increase in the cost of the apparatus are inevitable. Therefore, in the present invention, it is preferable to achieve the object by reducing the thickness of the photosensitive layer of the electrophotographic photosensitive member. Specifically, in the case where a light irradiation spot used in a conventional apparatus is used, a photoconductor having a thin photosensitive layer of about 10 to 20 μm is used.

Here, the relationship between the light intensity distribution, the spot diameter, and the product of the light spot area and the thickness of the photosensitive layer will be described with reference to FIG. The spot area of the light is the beam diameter measuring device LEPAS-1 manufactured by Hamamatsu Photonics Co., Ltd.
1 was used to measure the static light intensity distribution at the position of the photosensitive layer with respect to the light source, which was derived from the following relationship.
The light spot generally has an elliptical shape having a main scanning spot diameter (ab) and a sub-scanning spot diameter (cd) as shown in FIG. The product of the heights can be said to be the volume of the portion where the light spot is irradiated on the photosensitive layer. The spot area (S) of the light is an area on the photosensitive layer, and is represented by a cross-sectional area of a portion where the light intensity is 1 / e2 (B) or more of the peak intensity (A) (e is a natural logarithm). . Examples of the light source used include a semiconductor laser and an LED, and the light intensity distribution includes a Gaussian distribution and a Lorentz distribution. In any case, the intensity distribution is 1 / e2 (B) or more of the peak intensity (A). The spot area (S) is used.

Further, the image formation of the present invention is configured so that the product of the spot area of the irradiated light and the thickness of the photosensitive layer on the conductive support is 1,000 to 20,000 μm ^3. The method is characterized by using a specific two-component developer. Such a two-component developer has at least a toner and a magnetic carrier. First, the toner has a shape factor SF-1 in the range of 1.0 to 1.4 and a shape factor SF-2 of 1 to 1. Spherical toner having a particle diameter of at least 1 to 2.5, wherein a coating layer is provided on a surface of toner particles constituting the toner, in which at least granular lumps containing a silicon compound are fixed to each other. Is used. Such a spherical toner has much better fluidity and developability than an amorphous toner, but in addition to this, it has the specific coating layer on the surface of the toner particles, so that no external additive is used. The coating layer formed on the surface of the toner particles has sufficient fluidity and has appropriate irregularities as described later. As described above, the probability of contact with the carrier is reduced and the triboelectric charging property is not deteriorated. As a result, by using the toner having the above-described configuration, the photoconductor drum is separated from the surface of the toner particles, which is a serious problem in the image forming method using the photoconductor drum having the thin photosensitive layer as described above. It is possible to effectively prevent the image from being adversely affected by endurance caused by the external additives, and to obtain good triboelectrification and obtain a high-quality image stably.

Further, according to the image forming method of the present invention, among the toners having excellent fluidity and image characteristics constituted as described above, the number average particle diameter (D
₍₁ ) a narrow particle size distribution in which the cumulative value of the distribution not more than 1/2 times the diameter is 20% by number or less and the weighted average particle diameter (D ₄ ) whose cumulative value of the distribution not less than twice the diameter is 10% by weight or less; The toner having a small particle diameter having a weight average particle diameter of 1 to 10 [mu] m is used.
Thereby, the toner used in the image forming method of the present invention is
As a result of having a sharper charge amount distribution and maintaining the durability, a sufficiently high-definition image quality can be stably provided, especially even after a large number of prints.

Further, in the image forming method of the present invention, the magnetic carrier used in combination with the above-mentioned toner may have a shape factor SF.
−1 is in the range of 1.0 to 1.4, and the shape factor SF−
2 is in the range of 1.1 to 2.5, and in the particle size distribution, the number average particle size is 5 to 100 μm, and the distribution cumulative value of 1/2 or less of the number average particle size is 20 % Or less, and a magnetic carrier with a small diameter in a small area is used. As a result, the charging performance to the toner is improved,
Further, the distribution of the charge amount of the toner can be sharpened, and the above-described characteristics of the toner can be exhibited.

Next, the above toner and magnetic carrier will be described in more detail. As described above, in the present invention, the shape factor SF-1 of the toner is in the range of 1.0 to 1.4, and the shape factor SF-2 is in the range of 1.1 to 2.5. A toner having a coating layer formed by fixing at least particles containing a silicon compound on the surface of the toner particles constituting the toner is used. On the other hand, the magnetic carrier has a number average particle size of 5 to 100 μm in the particle size distribution, and a distribution cumulative value of not more than 1/2 times the number average particle size of the number average particle size is 20 number% or less. Has a shape factor SF-1 of 1.
0 to 1.4, and the shape factor SF-2 is 1.1
Use those that are in the range of ~ 2.5. The shape factor SF-1 of the toner and the magnetic carrier is an index indicating the sphericity of each particle. In the case of a true sphere, SF-1 = 1.
The shape factor SF-2 is an index indicating the degree of fine irregularities on the surface of the particles, and SF-2 = 1 when the surface is smooth without irregularities. Shape factors SF-1 and SF-
The calculation method of 2 will be described later.

In the image forming method of the present inventor, as described above, a charging step of charging an electrophotographic photosensitive member having a photosensitive layer provided on a conductive support, and a step of charging the charged electrophotographic photosensitive member It has an exposure step of irradiating the body with light, especially,
The product of the spot area of light irradiated in the exposure step and the thickness of the photosensitive layer is 1,000 to 20,000 μm ³ . As described above, in order to keep the product of the spot area of light irradiated in the exposure step and the thickness of the photosensitive layer in the above range, the thickness of the photosensitive layer should be substantially 20 μm or less. Is required. The present inventors have studied in detail the shapes of the magnetic carrier and the toner constituting the two-component developer used in such an image forming method, and when both of them are substantially spherical, the excellent fluidity of the developer is obtained. It was found that properties and development characteristics were imparted. As a means for confirming that the shapes of the toner and the magnetic carrier are substantially spherical, the value of the shape factor SF-1, which is an index indicating the sphericity, is used. It was found that an excellent effect was obtained when the ratio was 0.4. That is, the shape factor SF-1 of the toner and the magnetic carrier constituting the two-component developer is
Is greater than 1.4, the excellent fluidity of the two-component developer which is the object of the present invention may not be achieved.

Further, according to a detailed study by the present inventors,
Even when the shape factor SF-1 of the toner is in the range of 1 to 1.4, when the surface of the toner particles is too smooth, the probability of contact between the toner and the magnetic carrier is reduced and the triboelectric chargeability is reduced. It turned out to be worse. Then, in this case, uncharged toner particles are likely to be generated during print running, causing fogging and scattering of toner particles, and weak adhesion to magnetic carrier particles,
It has been found that a sufficient image density may not be obtained because toner particles are not conveyed. This is particularly noticeable in high-speed electrophotographic apparatuses that require rapid charging.

On the other hand, the present inventors have studied using a toner having fine irregularities on the surface of the toner.
It was found that a developer exhibiting extremely excellent charging characteristics was obtained. This is thought to be due to the fact that, when the toner particles making up the developer have moderate irregularities on the surface, when the toner comes into contact with the magnetic carrier, triboelectric charging is efficiently performed. .

As a result of further study, it was found that the fine irregularities on the surface of the toner used in the present invention were such that the granular mass containing at least the silicon compound was fixed to the surface of the toner particles constituting the toner. It was found to be formed by the coating layer in the state. The term “coating layer in a state in which the granular lumps containing at least the silicon compound are fixed to each other” in the present invention specifically means, for example, a toner obtained by hydrolysis and polycondensation of a silicon compound represented by silane alkoxide. It can be formed on the particle surface. A method for confirming that such a coating layer is formed and a method for forming the coating layer will be described later.

As a result of extensive studies by the present inventors, it has been found that a coating layer in which the above-mentioned granular lumps containing at least the silicon compound are fixed to each other is provided on the surface of the toner particles constituting the toner. It has been found that the toner is provided with sufficient fluidity without fine irregularities and without using an external additive as in the related art. And by adopting such a configuration, it is possible to maintain stable charging properties, and further, since no external additive is used,
It was also found that even when the development was performed continuously, the external additive was not released and the external additive was not embedded in the toner particles, and the durability was excellent. In particular,
The problem of abrasion of the photosensitive layer caused by liberated external additives which is important in the image forming method of the present invention using a photosensitive member having a substantially thin photosensitive layer is solved.

Further, in the image forming method of the present invention, in the particle size distribution, the weight average particle size is 1 to 10 μm,
When the cumulative distribution value of less than 1/2 the diameter of the number average particle diameter (D ₁ ) is 20 number% or less, and the cumulative distribution value of the twice or more diameter of the weight average particle diameter (D ₄ ) is 10 wt% or less. A small particle size toner having a sharp particle size distribution is used. Accordingly, the toner used in the image forming method of the present invention can form a fine image, has a sharper charge amount distribution, and can maintain its durability. As a result,
In particular, it is possible to provide sufficiently high-definition image quality even after a large number of prints.

The method for measuring the weight average particle size and the particle size distribution of the toner according to the present invention will be described. Regarding the particle size of the toner, a Coulter Counter TA-II is used, and a surfactant (preferably an alkylbenzene sulfonate) is used as a dispersant in 100 to 150 ml of an aqueous electrolytic solution.
Add 1 to 5 ml, and further add 2 to 20 mg of the measurement sample.
The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the volume and number of toner particles of 0.6 μm or more were measured using a 100 μm aperture as the aperture by the Coulter Counter TA-II. Then, a volume distribution and a number distribution were calculated. The number average particle size and the weight average particle size were thereby calculated, and the obtained number average particle size was used as the particle size of the toner. The measured number-average particle diameter and weight-average particle diameter are obtained by computer processing, and the cumulative ratio of the number-average particle diameter smaller than 1 / 2-number cumulative diameter distribution is calculated from the number-based particle diameter distribution. Find the cumulative value below the distribution. Similarly, a cumulative ratio equal to or larger than the double diameter cumulative distribution of the weight average particle diameter is calculated from the volume-based particle size distribution, and a cumulative value equal to or larger than the double diameter cumulative distribution is obtained.

Although the toner constituting the two-component developer of the present invention has the above-mentioned characteristics, the magnetic carrier used together with such a toner is also substantially spherical and has a shape factor SF-1 of 1.0 to 1.0. 1.4, and a shape factor SF-2 indicating the degree of unevenness of the particle surface.
Has to be in the range of 1.1 to 2.5. That is, when the magnetic carrier has a shape factor SF-2 of less than 1.1, the surface becomes too smooth, and the frictional charging characteristics of the toner may be impaired. On the other hand, the fine irregularities on the surface of the magnetic carrier can be formed by exposing the surface of metal oxide particles containing a magnetic material, resin fine particles, or the like.
When the particle size is larger than 5, the surface exposure of these fine particles becomes too large, and these fine particles are easily detached from the surface of the magnetic carrier particles. It is not preferable because it causes disturbance.

The magnetic carrier having a shape factor SF-2 in the range of 1.1 to 2.5 can be obtained by using a magnetic material-dispersed resin magnetic carrier or a coated resin carrier whose surface characteristics are easily controlled. Can be For example, in the case of a resin magnetic carrier particle of a magnetic material dispersion type, as a method for forming fine irregularities on the surface of the magnetic carrier, magnetic fine particles to be present inside the carrier or metal oxide fine particles containing a magnetic material are exposed to the surface. Can be formed.
In the case of a coated resin carrier, metal oxide fine particles or resin fine particles are added to a coating resin for coating the surface of a magnetic carrier particle of a magnetic substance alone such as ferrite magnetic carrier particles, and these are appropriately mixed. It can be formed by a method such as making a projection exposed on the surface in a suitable state.

The method of calculating the shape factors SF-1 and SF-2 of the respective particles constituting the toner and the magnetic carrier used in the present invention will be described below. These shape factors were measured by randomly taking 100 enlarged photographs of toner particles and magnetic carrier particles by a field emission scanning electron microscope S-4500 manufactured by Hitachi, Ltd. Image processing analyzer Lu
The analysis is performed using zex3, the shape factor derived by the following equation is calculated, and the average is obtained.

[0035]

(Equation 1)

Further, a two-component developer comprising at least a toner and a magnetic carrier used in the image forming method of the present invention will be described in detail. First, a description will be given of a coating layer formed on a surface of toner particles constituting the toner used in the present invention, which is formed by fixing particulate souls containing at least a silicon compound to each other. In order to examine the surface state of the toner particles having the coating layer, a cross section of the particles constituting the toner was examined by a transmission electron microscope (TE).
As a result of the observation in M), it was possible to observe a state in which a layered structure composed of granular lumps having a diameter of several tens of nm was formed on the surface of the toner particles.

Further, an electron probe mic using a scanning electron microscope (SEM) equipped with an X-ray microanalyzer (electron probe mic).
As a result of examining the surface configuration of the toner particles before and after cleaning the toner with a surfactant by EPA (roanalysis: EPMA), it was found that the reduction rate of the silicon element caused by the cleaning was small.
It was confirmed that instead of simply adhering to the surface of the toner particles, the granular masses were present on the surface of the toner particles in a state of being fixed to each other, forming a coating layer.

Hereinafter, a method for confirming the layer structure of the “coating layer formed by fixing the granular lumps containing at least the silicon compound”, which is a constituent element of the toner used in the present invention, will be described. In the present invention, the following procedure was used to confirm the coating layer formed by fixing the granular lumps containing at least the silicon compound.

<Confirmation of coating layer formed by fixation of granular lumps containing silicon compound> Confirmation of presence / absence of layer structure by transmission electron microscope observation Embed toner particles in epoxy resin. After solidifying with a microtome, an ultra-thin section of the toner particles is created and fixed in a measuring cell for a transmission electron microscope.
This was used as a sample for measurement. Hitachi H-750
The above sample was observed with a 0-type transmission electron microscope at a magnification of 10,000 to 50,000 times, and it was confirmed that a layer structure of a granular mass was present on the surface of the toner particles.

<Confirmation of Attachment of Granular Aggregates by Reduction Rate of Silicon Element Existence on Surface of Toner Particles after Surfactant Washing> (1) Existence of silicon atoms on toner particle surface by electron probe microscopic analysis Measurement of Amount (% by Mass) The surface of the toner particles was measured using an S-4500 type field emission scanning electron microscope manufactured by Hitachi, Ltd. equipped with an X-ray microanalyzer X-5770W manufactured by Horiba, Ltd. , Acceleration voltage 20 kV, absorption current value of sample 1.0 ×
Electron probe microscopic analysis was performed under the conditions of 10 ^-10 A and 25,000 times, and the abundance of silicon atoms when the total amount (% by mass) of carbon atoms, oxygen atoms, and silicon atoms was 100% Si ₁ (% by mass) was measured. The measurement was performed for 20 visual fields, and the average value was used as the measured value.

(2) Cleaning of Particle Surface of Toner with Surfactant 0.2 g of the toner is dispersed in 5 ml of a 5% aqueous solution of dodecylbenzenesulfonic acid, and the dispersion is applied to an ultrasonic cleaner for 30 minutes to sufficiently clean the particle surface of the toner. Washed. Further, centrifugation and washing were repeated to completely remove dodecylbenzenesulfonic acid from the toner particle surface, and then dried under reduced pressure to isolate the toner.

(3) Measurement of abundance (% by mass) of silicon atoms on the surface of toner particles after washing with a surfactant surfactant Abundance of silicon atoms desorbed from the surface of toner particles by the above operation (2) In order to measure (mass%), an electron probe microscopic analysis of the surface of the particles of the toner after washing with the surfactant was performed in the same manner as in the above (1) to determine the abundance of silicon atoms Si ₂ (mass%). It was measured.

[0043] (4) of the coating layer formed by the granular mass together comprising toner particles silicon compound provided on the surface state of the analysis above (1) to the Si ₁ and Si ₂ obtained by the procedure of (3) From the values, the reduction rate of the abundance of the silicon element on the surface of the toner particles caused by the surfactant washing was calculated by the following equation. When the rate of reduction of the abundance ratio of the silicon element on the surface of the toner particles is extremely small, the coating layer formed on the surface of the toner particles by the granular lumps containing the silicon compound adheres in a state where it is difficult to fall off the surface. Can be determined to be. Therefore, the reduction rate of the abundance of the silicon element on the surface of the toner particles obtained by the following equation is 3%.
When the content is 0% or less, the coating layer formed on the surface of the toner particles is considered to be in a state in which the granular masses containing the silicon compound constituting the layer are firmly fixed to each other, and the silicon compound This is a means for confirming whether or not the granular lumps including the particles are in a fixed state.

[0044]

(Equation 2)

As described above, in the present invention,
Combining the visual confirmation of the layer structure by the granular mass by transmission electron microscopy observation and the measurement result of the reduction rate of the silicon element abundance on the toner particle surface generated before and after the surfactant washing, and combining this with "at least Coating layer formed by fixation of granular lumps containing silicon compound "
Confirmation means.

As confirmed by the above method, in the toner used in the present invention, the coating layer on the surface of the toner particles constituting the toner is formed by fixing at least the granular lumps containing the silicon compound. As a result, fine irregularities are present on the surface of the toner particles, thereby realizing excellent charging characteristics.
In the present invention, as a typical example of the production of the toner, a coating layer is formed on the surface of the toner particles by a polycondensate of a silicon compound according to a sol-gel method described below. It takes the form of a film, and
A film in a state in which the granular masses containing the polycondensate of the silicon compound are chemically bonded to each other is formed into a coating layer covering the entire surface of the toner particles. For this reason, as in the case where a conventional fluidizing agent such as silica is adhered to the surface of the toner particles described above, there is room for generation of unattached free fine particles due to the addition of the fluidizing agent and free fine particles due to deterioration in durability. There is no. Therefore, the toner used in the present invention has excellent durability.

According to a detailed study of the present inventors, it has been found that EPM
When the amount of silicon element present on the particle surface of the toner is measured by A, the amount is preferably 0.10 to 2
0.0 mass%, more preferably 0.1 to 10.0
Mass%, more preferably 0.10 to 4.0 mass%.
It has been found that a coating layer in a more preferable state can be obtained when the ratio is within the range described above.

That is, a coating layer formed by fixing granular particles containing a silicon compound such that the abundance of silicon atoms on the surface of the toner particles is 0.10% by mass or more is fixed on the surface of the toner particles. It was confirmed that, when provided, the toner could be provided with higher fluidity and better charging characteristics. Further, when the abundance of silicon atoms on the surface of the toner particles provided with the coating layer formed by fixing the granular lumps containing the silicon compound is 0.10% by mass or more, the granular Since the surface of the toner particles is covered in a sufficient state by the coating layer formed by the agglomeration of the lumps, it is possible to impart higher fluidity to the toner and a sufficient charge amount. A toner is obtained.

On the other hand, it was found that by providing a coating layer in which the amount of silicon atoms on the surface of the toner particles was 20.0% by mass or less, the toner exhibited better fixability. This is because, in the case of a coating layer in which the amount of silicon atoms present on the surface of the toner particles satisfies the above conditions, the thermoplasticity of the binder resin constituting the toner particles is sufficiently exhibited. I think that the.

A method for measuring the abundance (% by mass) of silicon atoms in the particle cross section of the toner specified in the present invention will be described. <Method of Measuring Abundance of Silicon Atom in Cross Section of Toner> After embedding and solidifying the toner particles to be measured in an epoxy resin, an ultrathin section of the toner particles is prepared by a microtome to prepare a sample for measurement. This sample is placed on an aluminum sample stand for scanning electron micrographs and fixed using a conductive carbon adhesive sheet.
With respect to this sample, the amount of silicon atoms was quantified in the same manner as the above-described method for measuring the amount of silicon atoms present on the particle surfaces of the toner.

Further, as a result of a series of studies of the present invention, in the toner used in the present invention, more favorable effects are obtained when the amount of silicon atoms in the cross section of the toner particles is 4.0% by mass or less. I knew it could be done. Such a configuration is easily achieved by using a compound having an organic substituent in the silicon compound in the coating layer formed by fixing the granular masses containing at least the silicon compound. It was also found that the durability of the toner could be further improved. This is probably due to the use of those having organic substituents in the silicon compound in the coating layer, which added the flexibility of the organic chains to the formed coating layer, resulting in excellent durability. Believe in things.

That is, when there is an organic substituent in the silicon compound in the coating layer formed by fixing the granular masses containing at least the silicon compound, the amount of carbon atoms present on the particle surface of the toner increases. In other words, when the total amount of carbon atoms, oxygen atoms and silicon atoms is assumed to be 100%, the amount of silicon atoms is considered to be reduced. As a result of comparing and examining the abundance of atoms and the durability of the toner, the abundance of silicon atoms on the particle surface of the toner was determined to be 100% of the total abundance of carbon, oxygen and silicon atoms.
When the content is 4.0% by mass or less, it is found that the durability of the coating layer formed becomes higher, which makes it possible to further improve the durability of the toner of the present invention. .

In the method for producing a toner used in the present invention, toner particles serving as a matrix composed of at least a binder resin and a colorant are prepared, and the surface of the toner particles is formed by a method described below to obtain a granular material containing at least a silicon compound. A coating layer formed by fixing the lumps together is formed. As the toner particles, any conventionally known toner particles containing at least a binder resin and a colorant, and if necessary, various additives may be used. That is, the toner particles used in the present invention, after kneading a toner composition comprising a binder resin and other optional components,
A so-called pulverized toner obtained by cooling and kneading the kneaded product may be used, or a so-called polymerized toner obtained by polymerizing a polymerizable monomer serving as a binder resin may be used. . However, in the toner used in the present invention, if the shape of the toner particles is irregular, friction between the toner particles causes the above-described coating layer formed on the surface to be easily deteriorated. As the toner, spherical toner particles having a toner shape factor SF-1 in the range of 1.0 to 1.4 are used. Incidentally, such spherical toner particles are:
It can be easily obtained by spheroidizing the toner particles produced by the pulverization method or by producing the toner particles by the polymerization method.

As a typical example of the production of the coating layer formed by fixing the granular lumps containing at least the silicon compound of the present invention, application of a method generally called a sol-gel method may be mentioned. it can. Hereinafter, a production example by the sol-gel method will be described. The sol-gel method is generally known as a technique for producing a planar metal compound polycondensation film or a solid metal compound polycondensate.
It is generally called a sol-gel film.

The sol-gel film is specifically formed by hydrolytic polycondensation of a silicon compound typified by silane alkoxide, and its surface has fine irregularities on the order of nm. The present inventors have conducted intensive studies, and as a result, by providing this sol-gel film on the surface of the toner particles, a sufficient charge amount can be imparted without using an external additive as in the conventional toner. ,and,
It has been found that a toner is obtained in which the performance of the toner hardly deteriorates due to durability.

As a first method for forming a coating layer formed by fixing at least particles containing a silicon compound on the surface of toner particles, a toner containing at least a binder resin and a colorant is used. From outside the particle,
There is a method in which a polycondensate of a silicon compound is deposited on the surface of the toner particles to form the coating layer on the surface of the toner particles.

Specifically, after toner particles serving as a base are dispersed in water or an aqueous medium in which silane alkoxide is dissolved, the dispersion is dropped into water or an aqueous medium to which alkali has been added. There is a way to do that. According to this method, the silane alkoxide dissolved in the dispersion solution containing the toner particles undergoes hydrolysis and polycondensation in the presence of an alkali, gradually insolubilizes, and further becomes hydrophobic. The interaction results in deposition on the surface of the toner particles. As a result, a coating layer is formed on the surfaces of the toner particles by fixing the granular lumps containing at least the silicon compound. Further, when the toner particles obtained by the dispersion polymerization described above are used, the reaction system after the completion of the polymerization of the base toner particles is cooled to room temperature, and then the silane compound is dissolved therein and used as a toner dispersion. it can.

As the aqueous medium used above, for example, alcohols such as methanol, ethanol and isopropanol are used. When the organic nature of these solvents increases, the solubility of the polycondensate of silane alkoxide increases. This makes it difficult for polycondensates of silane alkoxide to deposit on the surface of the toner particles. Therefore, it is preferable to use methanol or ethanol as the aqueous medium.

As a second method of forming a coating layer formed by fixing at least particles containing a silicon compound on the surface of toner particles, at least a binder resin and a colorant are contained. And, by dispersing the toner particles in which the silicon compound is contained, in water, or a mixed solvent of an aqueous solvent and water, hydrolysis and polycondensation of the silicon compound are performed on the surface of the toner particles, There is a method of forming the coating layer.

In the above method, the toner particles are
When dispersed in water or a mixed solvent of an aqueous solvent and water, the silicon compound contained in the toner particles comes into contact with water on the surface of the toner particles and undergoes hydrolysis. That is, the sol-gel reaction proceeds only near the surface of the toner particles. Further, by washing with a solvent such as alcohol after completion of the reaction, unreacted silicon compounds remaining inside the toner particles can be removed. As a result, a polycondensate of the silicon compound is selectively present on the surface of the toner particles. It is possible to form a coating layer in which the abundance of silicon atoms on the particle surface is larger than the abundance inside the toner particles.

Here, the aqueous solvent refers to a solvent that can be dissolved in water, and the aqueous solvent suitable for dispersing the toner particles, which is suitable in the above method, is methanol,
Examples include alcohols such as ethanol and propanol, and mixed solvents thereof.

As a method of preliminarily incorporating the silicon compound in the toner particles, the silicon compound may be mixed at the time of the production of the toner particles, or the mother particles may be prepared by a conventional method and then added to the obtained particles. May be introduced. In this case, as a method of introducing the silicon compound into the toner particles after preparing the toner particles serving as the base, the silicon compound is swollen into the toner particles serving as the base in water or a mixed medium of water and an aqueous medium. Is effective. Specifically, the following methods are exemplified.

Specifically, for example, there is a method in which the toner particles serving as a base and the silicon compound are dispersed in a liquid medium in which the silicon compound is not dissolved, typically in water. In this way, the silicon compound slightly dissolved in the liquid medium,
The silicon compound is absorbed into the toner particles due to physical contact between the dispersed silicon compound and the toner particles, or the silicon compound is absorbed into the toner particles by diffusing in the liquid medium, and the silicon compound is incorporated into the toner particles. Can be introduced. In this case, it is preferable to use a surfactant in order to stably disperse the silicon compound in the liquid medium.
As the surfactant, a generally known surfactant can be used.

At this time, when a dispersion of the toner particles and a dispersion of the silicon compound are separately prepared and both are mixed,
It is not preferable to add the silicon compound dispersion to the toner particle dispersion because the toner particles tend to coalesce, resulting in a toner having a broader particle size distribution than the toner particles before the reaction. As a result, the obtained toner tends to have a problem that the distribution of the triboelectric charge amount becomes broad and the image is scattered. Therefore, in a case where a dispersion of toner particles and a dispersion of silicon compound are separately prepared and mixed, a method of adding the dispersion of toner particles to the dispersion of silicon compound is more preferable.

In order to maintain the particle size distribution of the toner particles before forming the coating layer after forming the coating layer on the surface of the toner particles to obtain the toner used in the present invention, the silicon compound is added to a liquid such as water. When dispersing in a medium, it is more preferable to disperse the silicon compound for each toner particle into droplets as small as possible. Further, as the method, it is preferable to use a method of mechanically stirring with a high-speed stirrer or the like, or a method of finely dispersing with an ultrasonic disperser or the like.

As described above, when the silicon compound is swelled and incorporated in the toner particles, the silicon compound and another poorly water-soluble solvent are used in combination for the auxiliary purpose such as increasing the swelling speed. A silicon compound can be swelled therein. As the poorly water-soluble solvent used at this time, any solvent may be used as long as it is a solvent having a higher hydrophilicity than the silicon compound to be used and a solvent which is hardly soluble in water. Specific examples include isopentyl acetate, isobutyl acetate, methyl acetate, ethyl acetate and the like. When these poorly water-soluble solvents are used, at any stage after the start of the polycondensation reaction of the silicon compound, the poorly water-soluble solvent is evaporated or the toner particles are charged into a hydrophobic medium. It is necessary to dissolve the poorly water-soluble solvent in the hydrophobic medium and remove it from the toner particles.
By performing the above operation, the unreacted silicon compound remaining in the toner particles can also be removed.

Further, as another method for swelling the silicon compound inside the toner particles serving as a base, the toner particles are dispersed in a liquid medium in which the silicon compound is dissolved, typically, alcohol, and the silicon compound is dispersed. There is a method of introducing a silicon compound into a toner by lowering the solubility. Examples of the method of lowering the solubility of the silicon compound include a method of lowering the temperature and gradually adding a liquid medium which is soluble in the liquid medium in which the silicon compound is soluble and which does not dissolve the silicon compound. As the latter method, specifically, for example, after dissolving a silicon compound in a low molecular weight alcohol such as methanol and dispersing the toner particles serving as a base, water is gradually added to lower the solubility of the silicon compound. And a method in which the silicon compound is swollen into toner particles and contained therein.

As described above, in the case where the method of dissolving the silicon compound and introducing the silicon compound into the inside of the toner particles is used, if the solubility of the silane alcohol after hydrolysis is high, Since the silane alcohol dissolves into the medium from the surface and the dissolved silane alcohols may form particles alone, select a medium in which the silane alcohol obtained by hydrolyzing the silicon compound is hardly soluble. There is a need to.

When the polycondensation reaction of the silicon compound proceeds on the surface of the parent toner particles in which the silicon compound is in a swollen state, the stirring speed is determined by the particle concentration in the system, the size of the system, the amount of swelling of the silicon compound, and the like. Although it depends on the particles, it is easy for the particles to coalesce if they are too slow or too fast,
Since it may cause the particle size distribution of the obtained toner to be disturbed,
The speed needs to be adjusted appropriately. In the above case, a general surfactant, a polymer dispersant, a solid dispersant, or the like may be used in order to stably disperse the base toner particles in the poorly water-soluble medium.

In the toner of the present invention, the coating layer formed on the surface of the toner particles and formed by fixing the granular lumps containing at least the silicon compound is specifically formed of silane by the method described above. It is a coating layer composed of a polycondensate of a silicon compound obtained by hydrolyzing a silicon compound such as alkoxide and then subjecting the compound to polycondensation. The above reaction basically proceeds at room temperature.

To obtain a film-like polycondensate as described above,
It is necessary to use at least one silicon compound having at least two hydrolysis and polycondensation groups in one molecule. However,
Monofunctional compounds can also be used in combination. Therefore, in the present invention, the following silicon compounds can be used when forming a coating layer formed by fixing at least the granular masses containing the silicon compound.

Examples of the bifunctional or higher functional silane alkoxide include, for example, tetramethoxysilane, methyltriethoxysilane, hexyltriethoxysilane, triethoxychlorosilane, di-t-butoxydiacetoxysilane, hydroxymethyltriethoxysilane, tetraethoxysilane. Silane, tetra-n-propoxysilane, tetrakis (2-methacryloxyethoxysilane) silane, allyltriethoxysilane, allyltrimethoxysilane,
-Aminopropyltriethoxysilane, 3-aminopropyltrimethoxylane, bis (triethoxysilyl) ethylene, bis (triethoxysilyl) methane, bis (triethoxysilyl) 1,7-octadiene, 2,2-
(Chloromethyl) allyltrimethoxysilane, ((chloromethyl) phenylethyl) trimethoxysilane, 1,
3-divinyltetraethoxydisiloxane, 2- (3,
4-epoxycyclohexyl) ethyltrimethoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, (3-glycidoxypropyl) methyldimethoxysilane, (3-glycidoxypropyl) trimethoxysilane, 3-mercapto Propyltriethoxysilane, methacrylamidopropyltriethoxysilane, methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane, 3- (methacryloxypropyl) trimethoxysilane, 1,7-octadienyltriethoxysilane, 7- Octenyltrimethoxysilane,
Examples include tetrakis (ethoxyethoxy) silane, tetrakis (2-methacryloxyethoxy) silane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, and vinyltriphenoxysilane.

The monofunctional silane alkoxide which can be used in combination with the above-mentioned bifunctional or higher silane alkoxide is, for example, (3-acryloxypropyl)
Dimethylmethoxysilane, o-acryloxy (polyethyleneoxy) trimethylsilane, acryloxytrimethylsilane, 1,3-bis (methacryloxy) -2-trimethylsiloxypropane, 3-chloro-2-trimethylsiloxypropene, (cyclohexenyloxy) trimethyl Silane, methacryloxyethoxytrimethylsilane,
(Methacryloxymethyl) dimethylethoxysilane.

Further, as a sol-gel reactive compound other than silane alkoxide, for example, aminosilane such as 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasilazane may be used. it can. These sol-gel reactive compounds can be used alone or
More than one type may be used in combination.

In general, in the sol-gel reaction, it is known that the formed state of the sol-gel film differs depending on the acidity of the reaction medium. Specifically, when the medium is acidic, H ⁺ is electrophilically added to oxygen of the alkoxy group (（OR group) to be eliminated as an alcohol. The water then attacks nucleophilically and is replaced by a hydroxy group. On this occasion,
When the content of water in the medium is low, the substitution reaction of the hydroxy group is particularly slow, so that a polycondensation reaction occurs before all of the alkoxy groups attached to the silane are hydrolyzed, and the one-dimensional linear reaction is relatively easy. Polymers and two-dimensional polymers are easily formed.

[0076] On the other hand, when the medium is an alkaline, OH ^-
The alkoxy group is easily changed to silane alcohol by the nucleophilic substitution reaction of In particular, when a silicon compound having three or more alkoxy groups in the same silane is used,
Polycondensation occurs three-dimensionally, and a polymer having many three-dimensional cross-links, that is, a sol-gel film having high strength is generated. or,
The reaction is completed in a short time. Therefore, in order to form a sol-gel film on the surface of the toner particles serving as a base, it is preferable to promote the sol-gel reaction under alkaline conditions, and specifically,
It is preferable to carry out the reaction under an alkaline condition of pH 9 or more. Thereby, a sol-gel film having higher strength and excellent durability can be formed. The above-mentioned sol-gel reaction basically proceeds even at room temperature. However, since the reaction is accelerated by heating, heat may be applied to the reaction system as needed.

Next, the method of the present invention for producing toner particles serving as a base for forming a coating layer formed by fixing particulate masses containing at least a silicon compound to each other will be described. Examples of the polymerizable monomer that can be used when producing the parent toner particles by a polymerization method include, for example, styrene, o-methylstyrene, m-
Styrene monomers such as methyl styrene, p-methoxy styrene, p-ethyl styrene, pt-butyl styrene, acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate;
Isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate,
Ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, phenyl methacrylate Diaminomethyl, dimethylaminoethyl methacrylate, benzyl methacrylate, crotonic acid, isocrotonic acid, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, acroyl morpholine, 2-
Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylonitrile, methacrylonitrile, acrylic acid monomers such as acrylamide, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl ether, isobutyl ether,
vinyl ether monomers such as β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether, p-methoxyphenyl vinyl ether, butadiene, and itaconic acid Dibasic acid monomers such as, maleic acid, fumaric acid, monobutyl itaconate and monobutyl maleate;
Heterocyclic monomers such as vinylpyridine, 3-vinylpyridine, 4-vinylpyridine and N-vinylimidazole can be exemplified. These monomers may be used alone or in combination of two or more, and a suitable polymer composition can be selected by arbitrarily combining them so as to obtain preferable characteristics.

Further, as a polymerization solvent (a solvent in which the polymerizable monomer is dissolved but the polymer is not dissolved) which can be used when preparing the parent toner particles by the dispersion polymerization method, a solvent obtained by polymerization is used. A product (polymer) that precipitates as the polymerization proceeds can be used. Specifically, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tertiary butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tertiary pentyl alcohol, 1-
Hexanol, 2-methyl 1-pentanol, 4-methyl-2-pentanol, 2-ethylbutanol, 1-heptanol, 2-heptanol, 3-heptanol, 2
Linear or branched aliphatic alcohols such as -octanol and 2-ethyl 1-hexanol, butane, 2-methylbutane, n-hexane, cyclohexane, 2-methylpentane, 2,2-dimethylbutane, 2,3 -Dimethylbutane, heptane, n-octane, isooctane,
In addition to aliphatic hydrocarbons such as 2,2,3-trimethylpentane, decane, nonane, cyclopentane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, p-menthane, and bicyclohexyl, aromatic hydrocarbons and halogenated hydrocarbons Examples include hydrogens, ethers, fatty acids, esters, sulfur-containing compounds, and mixtures thereof.

Further, as the polymer dispersant usable in the dispersion polymerization, specifically, for example, polystyrene,
Polyhydroxystyrene, polyhydroxystyrene-acrylate copolymer, hydroxylstyrene-vinyl ether or vinyl ester copolymer, polymethyl methacrylate, phenol novolak resin, cresol novolak resin, styrene-acryl copolymer, vinyl ether copolymer Specifically, for example, polymethyl vinyl ether, polyethyl vinyl ether,
Polybutyl vinyl ether, polyisobutyl vinyl ether, polyvinyl alcohol, polyvinyl pyrrolidone,
Polyvinyl acetate, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, vinyl chloride, polyvinyl acetal, cellulose, cellulose acetate, cellulose nitrate, alkylated cellulose, hydroxyalkylated cellulose, specifically, hydroxymethyl cellulose, Hydroxypropyl cellulose, a saturated alkyl polyester resin, an aromatic polyester resin, a polyamide resin, a polyacetal, a polycarbonate resin, or a mixture thereof, or can be formed using an arbitrary ratio of the monomers forming the polymer compound described above. Copolymers can be mentioned.

The toner of the present invention can contain a high molecular weight component or a gel component as a component of the toner, so that the melt viscosity characteristics such as prevention of offset can be adjusted as required. The introduction of such a component is achieved by using a crosslinking agent having two or more polymerizable double bonds per molecule. As such a crosslinking agent, specifically, for example, divinylbenzene,
Aromatic divinyl compounds such as divinylnaphthalene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,
3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate,
1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol tetramethacrylate, glycerol acroxydimethacrylate, N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone Can be mentioned.

These can be used alone or in combination of two or more. These crosslinking agents can be mixed in advance with the polymerizable monomer, or can be added as needed during the polymerization. The concentration of these crosslinking agents used in the present invention can be appropriately adjusted in consideration of the molecular weight, molecular weight distribution and the like of the polymer to be produced. It is preferable that the content be in the range of 01 to 5% by mass.

Examples of the binder resin that can be used when producing toner particles by a pulverization method include, for example, a styrene-substituted homopolymer such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate ester copolymer, styrene-methacrylic acid copolymer, styrene-α-chloromethyl methacrylate copolymer Polymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer , Styrene-acrylonitrile-indene copolymer Such styrene copolymers, polyvinyl chloride, phenolic resin, natural modified phenolic resin,
Naturally modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, cumarone indene resin, petroleum resin And the like. Crosslinked styrenic copolymers and crosslinked polyester resins are also preferred binder resins. In the toner of the present invention, the binder resin may contain a gel component in order to prevent offset during melting.

As the colorant constituting the toner particles serving as the base, any pigment or dye can be used, and both can be used in combination. As the black colorant to be used, for example, carbon black, a magnetic substance, and a black color tone using a yellow / magenta / cyan colorant shown below are used. As the yellow colorant, compounds represented by a condensed azo compound, an isoindolinone compound, an anthraquinone compound, an azo metal complex, a methine compound, and an allylamide compound are used. In particular,
C. I. Pigment Yellow 12, 13, 14, 15,
17, 62, 74, 83, 93, 94, 95, 97, 1
09, 110, 111, 120, 127, 128, 12
9, 147, 168, 174, 176, 180, 18
1, 191 are preferably used.

Examples of the magenta coloring agent include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8: 2, 48: 3, 48: 4, 57: 1, 81: 1, 1
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254 are particularly preferred.

As the cyan coloring agent, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66 can be particularly preferably used.

These colorants can be used alone or as a mixture, or can be used in the form of a solid solution. The amount of the colorant added is preferably 40 to 150 parts by mass per 100 parts by mass of the binder resin when a magnetic material is used, and 100 parts by mass of the binder resin when another colorant is used. It is preferable to add 5 to 20 parts by mass per unit.

Further, a charge control agent may be added to the toner of the present invention as needed. In this case, any conventionally known charge control agent can be used,
It is preferable to use a charge control agent which has a high toner charging speed and can stably maintain a constant charge amount.
Specifically, as the negative charge control agent, for example, salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphthoic acid, metal compounds such as dicarboxylic acid; sulfonic acid, a high molecular compound having a carboxylic acid in the side chain, It is preferable to use a boron compound, a urea compound, a silicon compound, calixarene and the like. As the positive charge control agent, for example, a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in a side chain, a guanidine compound, an imidazole compound, or the like is preferably used. These charge control agents are based on 100 parts by mass of the binder resin.
It is preferable to add in the range of 0.5 to 10 parts by mass.

Next, a magnetic carrier which is another component of the two-component developer used in the present invention will be described. As described above, in the present invention, a magnetic substance-dispersed resin carrier or a magnetic carrier of a magnetic substance alone such as ferrite coated on the surface can be used, but a more stable spherical magnetic carrier is used. Is preferred. Furthermore, in order to be able to permanently maintain the fine irregularities on the surface of the magnetic carrier, a thermosetting binder resin is used, the thermosetting binder resin is formed of a metal oxide, and a direct polymerization method is used. It is preferable to use the magnetic carrier obtained by the above.

Hereinafter, this method will be described. As a method of obtaining the magnetic substance-dispersed resin carrier particles which are a preferred form of the above magnetic carrier particles, a monomer of a binder resin and a metal oxide containing at least a magnetic fine powder are mixed and polymerized to directly form a magnetic carrier. There is a method of obtaining. The monomers used in the polymerization at this time include, in addition to the vinyl monomers exemplified when forming the toner, bisphenols and epichlorohydrin as starting materials for epoxy resins, phenols and aldehydes as starting materials for phenol resins. Urea and aldehydes as starting materials for urea resin, melamine and aldehydes as starting materials for melamine resin, and the like are used. For example,
When using a thermosetting phenolic resin as a binder resin to produce magnetic carrier particles used in the present invention,
In an aqueous medium, phenols and aldehydes as raw materials can be produced by mixing and polymerizing a metal oxide, preferably a metal oxide subjected to lipophilic treatment, in the presence of a basic catalyst.

Further, in the present invention, the magnetic carrier particles formed as described above are coated with a coating resin appropriately selected according to the charge amount of the toner, and the two-component developer of the present invention is optimally used. It is preferable to have a good chargeability and charge amount. The amount of the coating resin at this time is preferably in the range of 0.1 to 10% by mass, and more preferably 0.3 to 5% by mass. In the present invention, the shape coefficient SF-1 of the magnetic carrier after resin coating is 1.0 to 1.4, and the shape coefficient SF-
It is necessary to adjust the coating amount and the coating state so that 2 is in the range of 1.1 to 2.5. As the coating resin,
A thermosetting silicone resin or the like can be used.

As the coating resin that can be used as described above, an insulating resin can be suitably used. The insulating resin may be a thermoplastic resin or a thermosetting resin. Specifically, for example, as a thermoplastic resin, polystyrene, polymethyl methacrylate, acrylic resin such as styrene-acrylic acid copolymer, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, vinyl chloride, vinyl acetate, Polyvinylidene fluoride resin, fluorocarbon resin, perfluorocarbon resin, solvent-soluble perfluorocarbon resin, polyvinyl alcohol, polyvinyl acetal, polyvinylpyrrolidone, petroleum resin, cellulose, cellulose acetate, cellulose nitrate, methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, etc. Cellulose derivatives, novolak resin, low molecular weight polyethylene, saturated alkyl polyester resin, polyethylene terephthalate, polybutylene Terephthalate, aromatic polyester resins such as polyacrylate, polyamide resins, polyacetal resins, polycarbonate resins, polyethersulfone resins, polysulfone resins, polyphenylene sulfide resins, polyether ketone resins.

Specific examples of such curable resins include, for example, phenolic resins, modified phenolic resins, maleic resins, alkyd resins, epoxy resins, acrylic resins, and specifically, for example, maleic anhydride-terephthalic acid-
Unsaturated polyester, urea resin, melamine resin, urea-melamine resin, xylene resin, toluene resin, guanamine resin, melamine-guanamine resin, acetoguanamine resin, gliptal resin, furan resin, silicone resin obtained by polycondensation of polyhydric alcohol , A polyimide resin, a polyamide imide resin, a polyether imide resin, a polyurethane resin and the like. The above-mentioned resins can be used alone or in combination. Further, a curing agent or the like may be mixed with a thermoplastic resin and cured to be used. Further, a curing agent or the like may be mixed with the thermoplastic resin and cured.

The magnetic fine particles used in producing the above-described magnetic material-dispersed resin carrier include MO.Fe.
Magnetite represented by the general formula of ₂ O ₃ or MFe ₂ O ₄ ,
Ferrite and the like can be preferably used. here,
M is a divalent or monovalent metal, for example, Mn, F
e, Ni, Co, Cu, Mg, Zn, Cd, Li and the like. M may be a single metal or a plurality of metals. Specific magnetic fine particles include, for example, magnetite, gamma iron oxide, Mn-Zn ferrite, Ni-Zn ferrite, Mn-Mg ferrite, Ca-Mg ferrite, Li ferrite, Cu-Zn ferrite, etc. Can be used.

Further, in addition to the above-mentioned magnetic metal oxides, as a material for producing a magnetic material-dispersed resin carrier, M
g, Al, Si, Ca, Sc, Ti, V, Cr, Mn,
Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, N
A non-magnetic metal oxide using a single metal or a plurality of metals such as b, Mo, Cd, Sn, Ba, and Pb can be used. Specifically, for example, as a non-magnetic metal oxide, A
l ₂ O ₃ , SiO ₂ , CaO, TiO ₂ , V ₂ O ₅ , Cr
O ₂ , MnO ₂ , Fe ₂ O ₃ , CoO, NiO, CuO, Z
nO, SrO, Y ₂ O ₃ , ZrO _{2 and the} like can be used.

The magnetic carrier formed from the above-mentioned materials used in the present invention has a number average particle diameter of 5 to 1 in order to obtain a developer capable of forming a preferable image.
It is used in the range of 00 μm, and in the particle size distribution, the cumulative value of the distribution of 径 times the number average particle diameter or less is 20% by number or less. There is no particular limitation on the magnetic force of the magnetic carrier particles, but it is preferably about 20 to 300 emu / cm ³ in a magnetic field of 1 kOe.

Here, a method of measuring the number average particle diameter of the magnetic carrier used in the present invention and the distribution cumulative value of 1/2 times or less the number average particle diameter will be described. The particle size of the magnetic carrier used in the present invention is determined by a scanning electron microscope (100 to 5).
000 times), randomly extract 300 or more carrier particles having a particle size of 0.1 μm or more, and use an image processing analyzer Luzex3 manufactured by Nireco Co., Ltd. to obtain the carrier particle size using the Feret diameter in the horizontal direction. Was calculated. Furthermore, the distribution cumulative value of half the diameter or less of the number average particle diameter was calculated.

[0097]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited by the examples. First, toners 1 to 6, magnetic carriers 1 to 5, and an electrophotographic photosensitive member used in Examples and Comparative Examples were prepared as described below.

<Production of Toner> [Toner 1] 900 parts by mass of ion-exchanged water and 100 parts by mass of polyvinyl alcohol were previously added to a four-necked flask equipped with a high-speed stirrer TK-homomixer, and the rotation number was set to 1200 rpm. It was adjusted and heated to 60 ° C. to prepare an aqueous medium.

On the other hand, the following composition (1) was mixed at 60 ° C.
TK homomixer (manufactured by Tokushu Kika Kogyo)
Was stirred at 12,000 rpm to prepare a polymerizable monomer composition (hereinafter, referred to as a monomer dispersion). Further, 3 parts by mass of 2,2-azobisisobutyronitrile, which is a polymerization initiator, was dissolved therein, and then poured into the above-mentioned aqueous medium. The mixture was stirred at 000 rpm for 10 minutes, then heated to 80 ° C. while stirring with a paddle stirring blade, and reacted for 10 hours to polymerize. After completion of the polymerization reaction, the remaining monomer was distilled off under reduced pressure. After cooling, hydrochloric acid was added to dissolve the calcium phosphate, followed by filtration, washing with water, and drying to obtain polymer fine particles to be the base of the toner particles.

Composition (1) ・ Styrene monomer 88 parts by mass ・ n-butyl acrylate monomer 22 parts by mass ・ Carbon black 10 parts by mass ・ Salicylic acid metal compound 1 part by mass ・ Release agent 20 parts by mass

Subsequently, 0.9 parts by mass of the polymer fine particles were dispersed in 5.0 parts by mass of methanol, and then 0.5 parts by mass of tetraethoxysilane and 0.3 parts by mass of methyltriethoxysilane were used as silicon compounds. Parts, and
50 parts by mass of methanol was added to obtain a dispersion in which polymer fine particles were dispersed. Subsequently, 28% by mass
A solution composed of particles containing at least a polycondensate of a silicon compound by adding dropwise a solution obtained by adding 100 parts by mass of methanol to 10 parts by mass of an aqueous NH ₄ OH solution and stirring at room temperature for 48 hours. Was deposited on the surface of the polymer fine particles. After the completion of the reaction, the obtained particles are washed with purified water, and then washed with methanol, and then the particles are separated by filtration and dried. 1 covered with a coating layer composed of particles containing
I got

The particle diameter of the obtained toner 1 was measured by the above-mentioned method. As a result, the weight average particle diameter was 6.42 μm, and the distribution cumulative value was not more than half the number average particle diameter (D ₁ ). Was 5.3%, and the distribution cumulative value of twice or more the weight average particle diameter (D ₄ ) was 0.0%. Also, its shape factor SF
-1 was 1.06 and shape factor SF-2 was 1.20. When the surface of the toner particles constituting the toner 1 was observed with a scanning microscope photograph, a coating layer having fine granular irregularities having a diameter of about 40 nm was observed on the particle surface of the toner. Further, from observation of a cross section of the toner particles with a transmission electron microscope photograph, it was confirmed that a coating layer was formed on the surface of the toner particles constituting the toner 1.

Further, the abundance ratio of silicon atoms on the toner particle surface of Toner 1 determined by EPMA was 3.42% by mass. Similarly, the proportion of silicon atoms in the toner particle cross section of Toner 1 was 0.04% by mass. Therefore, the silicon atom abundance ratio on the toner particle surface is 85.50 times the silicon atom abundance ratio on the toner particle cross section, and the polycondensate of the silicon compound hardly exists inside the toner particle. I understood. Further, after the toner 1 was washed with a 5% aqueous solution of dodecylbenzenesulfonic acid, the abundance ratio of silicon atoms on the surface of the toner particles was 3.12% by mass. Therefore, when the reduction rate of silicon atoms present on the particle surface of the toner before and after washing with the surfactant was calculated,
8.72%. Therefore, it was confirmed that the coating layer formed on the surface of the toner particles constituting the toner 1 was a layer in which the granular mass was fixed.

[Toner 2] After dispersing 0.6 parts by mass of polymer fine particles serving as a base of the toner particles used in the production of toner 1 in 4.1 parts by mass of methanol, 2.5 parts by mass as a silicon compound Dissolve parts by weight of tetraethoxysilane,
Further, 40 parts by mass of methanol was added. Next, the dispersion in which the polymer particles are dispersed is added dropwise to an alkaline solution in which 100 parts by mass of methanol is mixed with 10 parts by mass of a 28% by mass aqueous NH ₄ OH solution, and the mixture is added at room temperature. By stirring for 48 hours, a film composed of particles containing at least a polycondensate of a silicon compound was deposited on the surface of the polymer fine particles serving as a base. After completion of the reaction, the obtained polymer fine particles are washed with purified water,
Then, after washing with methanol, the particles were separated by filtration and dried to obtain a toner 2 in which the surface of the polymer fine particles was coated with a coating layer composed of particles containing at least a polycondensate of a silicon compound. .

[0105] When the obtained particle size of the toner 2 was measured by the method described above, weight average particle diameter was 6.61Myuemu, number average particle diameter (D ₁₎ distribution cumulative value of under half size or less of Was 5.2%, and the cumulative distribution value of twice or more the weight average particle diameter (D ₄ ) was 0.0%. Also, its shape factor SF
-1 was 1.12 and shape factor SF-2 was 1.34. Further, when the surface of the toner particles constituting the toner 2 was observed with a scanning microscope photograph, a coating layer having fine granular irregularities having a diameter of about 40 nm was observed on the particle surface of the toner. Further, from observation of a cross section of the toner particles with a transmission electron microscope photograph, it was confirmed that a coating layer was formed on the surface of the toner particles constituting the toner 2.

The above toner 2 obtained by EPMA
The ratio of silicon atoms present on the surface of the toner particles was 9.
It was 48% by mass. Similarly, the proportion of silicon atoms in the particle cross section of the toner was 0.06% by mass. Therefore, the silicon atom abundance ratio on the toner particle surface is 158.00 times the silicon atom abundance ratio on the toner particle cross section, and the polycondensate of the silicon compound hardly exists inside the toner particle. Fell. Further, after the toner 2 was washed with a 5% aqueous solution of dodecylbenzenesulfonic acid, the existing ratio of silicon atoms on the surface of the toner particles was 7.63% by mass. Therefore, the reduction rate of silicon atoms present on the particle surface of the toner before and after washing with the surfactant was calculated to be 19.51%
Met. Therefore, it was confirmed that the coating layer formed on the surface of the toner particles constituting the toner 2 obtained above was a layer in which the granular mass was fixed to each other.

[Toner 3] As a monomer dispersion, 10 parts by mass of tetraethoxysilane as a silicon compound was further added to the composition of the monomer dispersion used in Toner 1, and an NH ₄ OH aqueous solution was added to the system. Was added, and the polymerization reaction temperature was set to 77 ° C., and the polymerization was carried out in the same manner as in the production method of toner 1 except that the monomer dispersion was made alkaline. As a result, during the production of the polymerized fine particles, the silicon compound contained in the particles,
The sol-gel reaction is easily caused by heat. Thereafter, by washing with a large amount of ethanol to remove unreacted tetraethoxysilane inside the particles, and further filtering and drying, a film composed of particles containing at least a polycondensate of a silicon compound becomes a matrix. A toner 3 provided on the surface of the polymer fine particles was obtained.

The particle diameter of the obtained toner 3 was measured by the above-mentioned method. As a result, the weight average particle diameter was 6.31 μm, and the distribution cumulative value was 個数 or less of the number average particle diameter (D ₁ ). Was 6.8%, and the cumulative distribution value of twice or more the diameter of the weight average particle diameter (D ₄ ) was 1.2%. Also, its shape factor SF
-1 was 1.08 and shape factor SF-2 was 1.40. Further, when the surface of the toner particles constituting the toner 3 was observed with a scanning microscope photograph, a coating layer having fine granular irregularities having a diameter of about 40 nm was observed on the particle surface of the toner. Further, from observation of a cross section of the toner particles with a transmission electron microscope photograph, it was confirmed that a coating layer was formed on the surface of the toner particles constituting the toner 3.

The content of silicon atoms on the particle surface of the toner determined by EPMA was 18.82% by mass. Similarly, the abundance ratio of silicon atoms in the cross section of the toner particles constituting the toner 3 is 3.61.
% By mass. Therefore, the abundance ratio of silicon atoms on the surface of the toner particles constituting the toner 3 is 5.21 times the abundance ratio of silicon atoms on the cross section of the toner particles. It was confirmed that a polycondensate of the silicon compound was present.
Further, after the toner 3 was washed with a 5% aqueous solution of dodecylbenzenesulfonic acid, the abundance ratio of silicon atoms on the surface of the toner particles was 18.02% by mass. Therefore, the reduction rate of silicon atoms present on the surface of the toner particles before and after cleaning the surfactant was calculated to be 4.24%. Therefore, it was confirmed that the coating layer formed on the surface of the toner particles constituting the toner 3 obtained as described above was a layer in which granular lumps were fixed.

[Toner 4] As a monomer dispersion, 10 parts by mass of tetraethoxysilane as a silicon compound was further added to the composition of the monomer dispersion used in Toner 1, and an NH ₄ OH aqueous solution was added to the system. The polymerization was carried out in the same manner as in the production of toner 1 except that the reaction temperature was adjusted to 77 ° C. and the monomer dispersion was made alkaline. As a result, during the production of the polymerized fine particles, the silicon compound contained in the particles is likely to cause a sol-gel reaction by heat. Thereafter, by washing with a large amount of ethanol to remove unreacted tetraethoxysilane inside the particles, and further by filtration and drying, from the particles containing at least a silicon compound polycondensate on the surface of the parent polymerized fine particles. Toner 4 provided with structured film
I got

[0111] When the obtained particle size of the toner 4 was measured by the method described above, weight average particle diameter was 6.51Myuemu, number average particle diameter (D ₁₎ distribution cumulative value of under half size or less of Was 6.6%, and the cumulative distribution value of twice or more the weight average particle diameter (D ₄ ) was 1.0%. Also, its shape factor SF
-1 was 1.08 and shape factor SF-2 was 1.35. Further, the surface of the toner particles constituting the toner 4 was observed with a scanning microscope photograph. As a result, a coating layer having fine granular irregularities having a diameter of about 40 nm was observed on the particle surface of the toner. Further, from observation of a cross section of the toner particles with a transmission electron micrograph, it was confirmed that a coating layer was formed on the surface of the toner particles constituting the toner 4.

Further, the abundance ratio of silicon atoms on the surface of the toner particles constituting the toner 4 determined by EPMA was 10.21% by mass. Similarly, the abundance ratio of silicon atoms in the cross section of the toner particles constituting the toner was 5.73%. Therefore, the abundance ratio of silicon atoms on the surface of the toner particles of the toner 4 is 1.78 times the abundance ratio of silicon atoms on the cross section of the toner particles.
It was confirmed that a polycondensate of the silicon compound was present. Further, after the toner 4 was washed with a 5% aqueous solution of dodecylbenzenesulfonic acid, the abundance ratio of silicon atoms on the surface of the toner particles was 9.18% by mass. Thus, the reduction rate of silicon atoms present on the particle surface of the toner before and after the surfactant was washed was calculated to be 10.05%. Therefore, it was confirmed that the coating layer formed on the surface of the toner particles constituting the toner 4 obtained as described above was a layer in which granular lumps were fixed to each other.

[Toner 5] The polymer fine particles used in the production of Toner 1 were used as Toner 5 without forming a coating layer on the surface. When the particle size of the toner 5 obtained above was measured by the method described above, the weight average particle size was 6.40 μm.
m, and the cumulative distribution value of the diameter not more than half of the number average particle diameter (D ₁ ) is 5.1%, and the weight average particle diameter (D ₄ ) is 2%.
The cumulative value of distribution having a diameter equal to or larger than the diameter was 0.0%. The shape factor SF-1 was 1.06, and the shape factor SF-2 was 1.05.

[Toner 6] A weight-average particle diameter of 40 n is based on 100 parts by weight of the polymer fine particles used in the production of the toner 1.
After adding 5 parts by mass of the hydrophobic silica fine powder of m, the mixture was mixed with a Henschel mixer to obtain a toner 6 in which the silica fine powder was externally added as a fluidizing agent.

When the average particle size of the toner 6 obtained above was measured by the method described above, the weight average particle size was 6.33 μm.
And the distribution cumulative value of the number average particle diameter (D ₁ ) or less twice the diameter is 5.1%, and the distribution cumulative value of the weight average particle diameter (D ₄ ) twice or more the diameter is 0.1%. It was 0%. The shape factor SF-1 was 1.06, and the shape factor SF-2 was 1.21. Observation of the toner 6 with a scanning microscope photograph showed that, although particles were observed on the surface of the toner particles constituting the toner 6, a large number of gaps existed between the particles. It was not a thing. Further, when a transmission electron micrograph of the cross section of the toner particles was observed, the presence of particles and a continuous layer were confirmed in some places on the surface of the toner particles, but no continuous layer was confirmed.

The content of silicon atoms on the surface of the toner particles constituting the toner 6 determined by EPMA was 0.52% by mass. Similarly, the proportion of silicon atoms in the cross section of the toner particles constituting the toner 6 was 0.00%. Further, 5% of this toner 6
After washing with an aqueous solution of dodecylbenzene sulfonic acid, the abundance ratio of silicon atoms on the surface of the toner particles was 0.35% by mass. Then, the reduction rate of silicon atoms present on the particle surface of the toner before and after cleaning the surfactant was calculated to be 32.04%. Therefore, this toner 6 had a high silicon reduction rate by washing with a surfactant, and the surface layer was not recognized as a fixed layer.

[Toner 7] Into a four-necked flask were charged 180 parts by mass of water purged with nitrogen and 20 parts by mass of an aqueous solution of 0.2 parts by mass of polyvinyl alcohol. And Then, after the inside of the flask was replaced with nitrogen, the temperature was raised to 80 ° C. and maintained at the same temperature for 10 hours to carry out a polymerization reaction. 88 parts by mass of styrene monomer 22 parts by mass of n-butyl acrylate 1.4 parts by mass of benzoyl peroxide 0.2 parts by mass of divinylbenzene After the polymer was washed with water, the temperature was kept at 65 ° C. while reducing the pressure. To obtain a binder resin.

90 parts by mass of the resin obtained above, 10 parts by mass of carbon black, 5 parts of a metal salicylate compound,
3 parts by mass of the release agent was mixed by a fixed-tank dry mixer, and the mixture was melt-kneaded by a twin-screw extruder while the vent port was connected to a suction pump for suction. Next, the melt-kneaded product was crushed by a hammer mill to obtain a crushed toner composition of 1 mm mesh pass. Further, after crushing the coarsely crushed product by a mechanical crusher to a volume average diameter of 20 to 30 μm, crushing is performed by a jet mill utilizing collision between particles in a swirling flow, and then by a multi-stage classifier. Classification was performed to obtain pulverized resin particles serving as a base.

Subsequently, 1.0 part by mass of the pulverized resin particles was dispersed in 5.0 parts by mass of methanol, and then 0.5 parts by mass of tetraethoxysilane and 0.3 parts by mass of methyltriethoxysilane were used as silicon compounds. Parts, and
50 parts by weight of methanol were added. Then, to this
A solution obtained by adding 100 parts by mass of methanol to 10 parts by mass of a 28% by mass aqueous NH ₄ OH solution was added dropwise,
By stirring at room temperature for 48 hours, a film composed of particles containing at least a polycondensate of a silicon compound was deposited on the surface of the toner particles. After completion of the reaction, the obtained particles are washed with purified water, then washed with methanol, and then filtered and dried, whereby the particles are coated with a coating layer composed of particles containing at least a polycondensate of a silicon compound. The toner that has been obtained.

[0120] As a result the particle size of the toner 7 obtained above was measured by the method described above, weight average particle diameter was 6.52Myuemu, distribution under half size or less of the number average particle diameter (D ₁₎ The cumulative value was 20.5%, and the distribution cumulative value of twice or more the weight average particle diameter (D ₄ ) was 11.0%. The shape factor SF-1 was 1.35 and the shape factor SF-2 was 1.46.

When the particle surface of this toner was observed with a scanning microscope photograph, a coating layer having fine granular irregularities having a diameter of about 40 nm was observed on the particle surface of the toner. Further, observation of a cross section of the particles of the toner with a transmission electron microscope photograph confirmed that a coating layer was formed on the surface of the particles of the toner. Further, the content ratio of silicon atoms on the particle surface of the toner determined by EPMA is 3.
It was 21% by mass. Similarly, the proportion of silicon atoms in the cross section of the toner particles was 0.08%. Therefore, the silicon atom abundance ratio on the toner particle surface was 40.13 times the silicon atom abundance ratio on the toner particle cross section, and the polycondensate of the silicon compound hardly existed inside the toner particles. .

Further, after the toner was washed with a 5% aqueous solution of dodecylbenzenesulfonic acid, the abundance ratio of silicon atoms on the surface of the toner particles was 2.92%. Therefore, the reduction rate of silicon atoms present on the surface of the toner particles before and after washing with the surfactant was 9.08%. Therefore, it was confirmed that the coating layer formed on the particle surface of the toner obtained above was a layer in which the granular lumps were fixed.

Table 1 summarizes the properties of the toners 1 to 7 obtained as described above.

[Table 1]

<Production of magnetic carrier> [Magnetic carrier 1] 10.2 parts by mass of phenol, formalin solution (formaldehyde about 40%, methanol about 1
0%, the remainder being water) 6.0 parts by mass, lipophilized magnetite (particle size 0.24 μm, specific resistance 5 × 10 ⁵ Ω · c)
m) 52 parts by mass of 34 parts by mass of lipophilized hematite (particle size: 0.60 μm, specific resistance: 8 × 10 ⁹ Ω · cm) were mixed. The lipophilicity of the magnetite and hematite used here was determined by adding 0.5% by mass of a titanate coupling agent (isofurohill triisostearoyl titanate) to each metal oxide at 100 ° C. and 0.1%. This was performed by mixing and stirring for 5 hours.

The above-mentioned mixed material, 28% ammonia water as a basic catalyst, and water were further placed in a flask, and the mixture was heated and maintained at 85 ° C. for 40 minutes while stirring and mixing, and reacted for 3 hours.
After curing, after cooling to 30 ° C. and adding 100 parts by weight of water, the supernatant was removed and the precipitate was washed with water,
Air dried. Then, this was reduced under pressure (5 mmHg or less),
After drying at 180 ° C., a spherical carrier core in which magnetite and hematite were combined with a phenol resin as a binder was obtained. The specific resistance of the obtained core was 1.6 × 10 ¹²
Ω · cm.

The surface of the obtained core particles was coated with a thermosetting silicone resin by the following method. First, toluene was used as a solvent so that the coating resin amount was 0.4% by mass.
A 0% by weight carrier coat solution was prepared. The solvent was volatilized while continuously applying shear stress to the coating solution to coat the magnetic carrier core particles. The coated carrier particles were cured at 180 ° C. for 2 hours, and thereafter, the coated carriers were classified using a multi-segmentation classifier to obtain a magnetic carrier 1.

The obtained magnetic carrier 1 had a number average particle size of 45.5 μm in the particle size distribution. or,
The cumulative value of distribution having a diameter equal to or less than 1/2 times the number average particle diameter was 5%. The shape factor SF-1 was 1.10 and the shape factor SF-2 was 1.40. Further, when the specific resistance of the magnetic carrier 1 was measured, it was 1.0 × 10 ¹³ Ω · cm
Met. Also, as a result of measuring the saturation magnetization of the magnetic carrier 1, the magnetization intensity at 1 kOe (σ ₁₀₀₀ )
= 129 emu / cm ³ (the true specific gravity of the magnetic carrier 1 is 3.49 g / cm ³ ).

[Magnetic Carrier 2] 11.7 parts by mass of phenol, 7.0 parts by mass of formalin solution (formaldehyde: about 40%, methanol: about 10%, balance water), lipophilic treatment used in magnetic carrier 1 53 parts by mass of magnetite (particle size 0.24 μm, specific resistance 5 × 10 ⁵ Ω · cm), lipophilicized hematite (particle size 0.60 μm, specific resistance 8 × 10 ⁹ Ω ·) used in the magnetic carrier 1 cm) 3
4 parts by weight were mixed.

The above mixed material and 28% as a basic catalyst
Ammonia water and further water were added to the flask, and the temperature was raised to and maintained at 85 ° C. for 40 minutes with stirring and mixing, reacted and cured for 3 hours, then cooled to 30 ° C., and 100 parts by mass of water was added. Thereafter, the supernatant was removed, and the precipitate was washed with water and air-dried. Next, this was dried at 180 ° C. under reduced pressure (5 mmHg or less) to obtain spherical carrier core particles in which magnetite and hematite were bound using a phenol resin as a binder. The specific resistance of the obtained core is as follows.
It was 5 × 10 ¹² Ω · cm.

The surface of the carrier core particles obtained above was coated with a silicone resin in the same manner as in the case of the magnetic carrier 1. The obtained magnetic carrier 2 had a number average particle size of 45.1 μm in the particle size distribution.
Also, the cumulative value of distribution below 1/2 times the number average particle diameter is 8%.
Met. The shape factor SF-1 was 1.12 and the shape factor SF-2 was 1.32. Further, when the specific resistance of the magnetic carrier 2 was measured, it was 1.1 × 10 ¹³
Ω · cm. Further, as a result of measuring the saturation magnetization of the magnetic carrier 2, the magnetization intensity (σ ₁₀₀₀ ) at 1 kOe was 130 emu / cm ³ (the true specific gravity of the magnetic carrier 2 was 3.51 g / cm ³ ).

[Magnetic Carrier 3] 11.4 parts by mass of phenol, 6.7 parts by mass of formalin solution (formaldehyde: about 40%, methanol: about 10%, balance water), lipophilic used in the production of magnetic carrier 1 88 parts by mass of magnetite (particle size 0.24 μm, specific resistance 5 × 10 ⁵ Ω · cm) was mixed. The above materials, 28% aqueous ammonia as a basic catalyst, and water are further placed in a flask, and the temperature is raised and maintained at 85 ° C. in 40 minutes while stirring and mixing, reacted and cured for 3 hours, and then cooled to 30 ° C. After adding 100 parts by mass of water, the supernatant was removed, and the precipitate was washed with water and air-dried. Then, this is reduced under reduced pressure (5 mmHg or less), 1
After drying at 80 ° C., spherical carrier core particles obtained by combining magnetite with a phenol resin as a binder were obtained.
The specific resistance of the obtained core particles is 3.2 × 10 ⁸ Ω · cm.
Met.

The surface of the carrier core particles obtained above was coated with a thermosetting silicone resin by the following method. First, a 10% by mass carrier coat solution was prepared using toluene as a solvent so that the amount of the coat resin was 1.0% by mass. Next, the coating was performed on the carrier core particles by volatilizing the solvent while continuously applying shear stress to the coating solution. The coated carrier particles were cured at 180 ° C. for 2 hours, and thereafter, the coated carriers were classified using a multi-segmentation classifier to obtain a magnetic carrier 3.

The resulting magnetic carrier 3 had a number average particle size of 45.3 μm in the particle size distribution. or,
The cumulative distribution value of the number average particle size of 1/2 or less was 10%. The shape factor SF-1 is 1.11,
The shape factor SF-2 was 1.24. Furthermore, when the specific resistance of the magnetic carrier 3 was measured, it was 1.8 × 10 ¹⁰ Ω ·
cm. Also, as a result of measuring the saturation magnetization of the magnetic carrier 3, the magnetization intensity at 1 kOe (σ
₁₀₀₀ ) = 225 emu / cm ³ (the true specific gravity of the magnetic carrier 3 is 3.42 g / cm ³ ).

[Magnetic carrier 4] 11.0 parts by mass of phenol, 6.5 parts by mass of a formalin solution (formaldehyde: about 40%, methanol: about 10%, water: balance), lipophilic ferrite (particle size: 0.24 μm) , Specific resistance 6 × 10 ⁷
(Ω · cm) was mixed.

The above mixed material and 28% as a basic catalyst
Ammonia water and further water were added to the flask, and the temperature was raised to and maintained at 85 ° C. for 40 minutes with stirring and mixing, reacted and cured for 3 hours, then cooled to 30 ° C., and 100 parts by mass of water was added. Thereafter, the supernatant was removed, and the precipitate was washed with water and air-dried. Next, this was dried at 180 ° C. under reduced pressure (5 mmHg or less) to obtain spherical carrier core particles in which magnetite was bound using a phenol resin as a binder. The specific resistance of the obtained core particles is 6.8 × 10 ⁸
Ω · cm.

Next, the surface of the carrier core particles obtained above was coated with a thermosetting silicone resin by the following method. First, a 10% by mass carrier coat solution was prepared using toluene as a solvent so that the amount of the coat resin was 1.0% by mass. The solvent was volatilized while continuously applying shear stress to the obtained coating solution to coat the core particle surface. The coated carrier particles were cured at 180 ° C. for 2 hours, and then the coated carriers were classified using a multi-segmentation classifier to obtain a magnetic carrier 4.

The resulting magnetic carrier 4 had a number average particle size of 45.3 μm in the particle size distribution. or,
The cumulative value of distribution having a diameter equal to or less than half the number average particle diameter was 15%. The shape factor SF-1 is 1.13,
The shape factor SF-2 was 1.34. Further, when the specific resistance of the magnetic carrier 4 was measured, it was 7.5 × 10 ¹⁰ Ω ·
cm. Also, as a result of measuring the saturation magnetization of the magnetic carrier 4, the magnetization intensity (σ
₁₀₀₀ ) = 245 emu / cm ³ (the true specific gravity of the magnetic carrier 4 is 3.55 g / cm ³ ).

[Magnetic Carrier 5] 65 parts by mass of iron dioxide, 18 parts by mass of copper oxide and 16 parts by mass of zinc oxide were mixed by a ball mill. After calcining this, it was pulverized by a ball mill and further granulated by a spray drier. This was sintered to obtain carrier core particles.
The specific resistance of the obtained core particles is 5.8 × 10 ⁸ Ω · cm.
Met.

The surface of the core particles obtained above was coated with a thermosetting silicone resin by the following method. First,
A carrier coat solution of 10% by mass was prepared using toluene as a solvent so that the amount of the coat resin was 1.0% by mass. Next, the coating solution was applied to the surface of the carrier core particles by volatilizing the solvent while continuously applying shear stress to the coating solution. The coated carrier particles were cured at 180 ° C. for 2 hours, and thereafter, the coated carriers were classified using a multi-segment classifier to obtain a magnetic carrier 5.

The obtained carrier 5 had a number average particle size of 44.8 μm in the particle size distribution. The cumulative distribution value of the number average particle size of 1/2 or less was 22%.
The shape factor SF-1 is 1.32, and the shape factor SF
-2 was 1.12. Further, when the specific resistance of the carrier particles was measured, it was 3.0 × 10 ¹⁰ Ω · cm.
Also, as a result of measuring the saturation magnetization of the carrier particles, the intensity of magnetization at 1 kOe (σ ₁₀₀₀ ) = 280 em
u / cm ³ (the true specific gravity of the magnetic carrier 5 was 4.9.
5 g / cm ³ ).

The magnetic carrier 1 obtained as described above
Table 2 summarizes the properties of Nos. To 5.

[Table 2]

[Preparation of Electrophotographic Photoreceptor] The electrophotographic photoreceptor used in Examples and Comparative Examples is a drum-shaped photosensitive member having a conductive layer, an undercoat layer, a charge generation layer and a charge transport layer on an aluminum cylinder in this order. Body. Here, the charge generation layer contained oxytitanium phthalocyanine and had a thickness of 0.1 μm. Further, by adjusting the thickness of the charge generation layer, three types of electrophotographic photosensitive members A having photosensitive layers of 10 μm, 15 μm, and 27 μm, respectively, are provided.
(10 μm), B (15 μm) and C (27 μm). A semiconductor laser having a wavelength of 680 nm and an output of 35 mW was used as an exposure light source when exposing these electrophotographic photosensitive members A to C after exposure. The light irradiated on the photoreceptor has a spot diameter of 25 mm in the main scanning direction.
63.5 μm in the sub-scanning direction (μm
The light b of 0 μm ² ) and the light a of 25 μm in the main scanning direction and 45 μm in the sub-scanning direction (spot area 900 μm ² ) were used.

<Example 1> The carrier 1 and the toner 1 obtained above were mixed so as to have a toner concentration of 8% by mass.
A two-component developer was prepared. The charge amount of the toner is -24.
It was 3 μC / g. Using this two-component developer, an electrophotographic photoreceptor A having a photosensitive layer thickness of 10 μm and a semiconductor laser having a light spot area of 900 μm ² on the photoreceptor as an exposure light source (the spot of the light a to be irradiated) The product of the area and the thickness of the photosensitive layer of the electrophotographic photosensitive member A is 9,000 μm ³ ). A full-color laser copying machine CLC500 manufactured by Canon Inc. is incorporated in the modified machine, and an image output test and a multi-sheet durability test are performed. Was.

The test pattern of 400 dpi and 256 gradations was visually evaluated and the density of each gradation was measured with a Macbeth densitometer to evaluate the gradation reproducibility. In addition, the transfer efficiency of the toner in the solid black image was measured by dividing the toner weight per unit area after transfer (on transfer paper) by the toner weight per unit area on the photoconductor before transfer. Further, the image after outputting 50,000 sheets of images was visually evaluated, and the shaved amount of the photoreceptor was measured by an eddy current film pressure meter.

As a result, in the present embodiment, with respect to the test pattern of 256 gradations, a change in density was observed for all gradations, and the amount of scraping of the photoreceptor after 50,000 sheet durability was also 0.5 μm.
It was found that excellent durability performance was obtained as follows. Also, none of the formed images had image defects such as black spots. The transfer efficiency of the toner was as high as 96%. Table 3 summarizes the obtained results.

<Example 2> The above-described carrier 2 and toner 2 were mixed so as to have a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was -24.3 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm, and a semiconductor laser having a spot area of 900 μm ² on the photosensitive member as an exposure light source (the light a The product of the spot area and the thickness of the photosensitive layer was 13,500 μm ³ ), and an image output test and a durability test of many sheets were performed using a modified machine of a full color laser copying machine CLC500 manufactured by Canon Inc.

When evaluation was performed in exactly the same manner as in Example 1, a density change of 220 or more gradations was observed for a 256-tone test pattern, and the photoreceptor scraping amount after running 50,000 sheets was 0.7 μm. Although inferior to Example 1, it exhibited excellent durability performance. There were no image defects such as black spots. The transfer efficiency of the toner was as high as 93%. Table 3 shows the obtained results.
Are shown together.

<Example 3> The above-mentioned carrier 1 and toner 3 were mixed at a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was −25.2 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm and a semiconductor laser having a spot area of 900 μm ² on the photosensitive member as an exposure light source (a light a The product of the spot area and the thickness of the photosensitive layer was 13,500 μm ³ ), and an image output test and a durability test of many sheets were performed using a modified machine of a full color laser copying machine CLC500 manufactured by Canon Inc.

When evaluation was performed in exactly the same manner as in Example 1, a change in density was observed for all gradations in the 256-tone test pattern. Excellent durability performance was exhibited. There were no image defects such as black spots. Transfer efficiency of toner is 95
% Was high. Table 3 summarizes the obtained results.

Example 4 The above-mentioned carrier 1 and toner 4 were mixed so as to have a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was -23.6 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm and a semiconductor laser having a spot area of 900 μm ² on the photosensitive member as an exposure light source (a light a The product of the spot area and the thickness of the photosensitive layer was 13,500 μm ³ ), and an image output test and a durability test of many sheets were performed using a modified machine of a full color laser copying machine CLC500 manufactured by Canon Inc.
The transfer efficiency of the toner was 96%.

Evaluation was performed in exactly the same manner as in Example 1. As a result, a change in density was observed for all gradations in the 256-tone test pattern, and the photoreceptor abrasion after 50,000 sheets of durability was as excellent as 0.5 μm or less. Endurance performance. There were no image defects such as black spots. 94% transfer efficiency of toner
And it was high. Table 3 summarizes the obtained results.

Example 5 The above-mentioned carrier 2 and toner 1 were mixed at a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was −25.1 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm and a semiconductor laser having a spot area of 1,250 μm ² on the photosensitive member as an exposure light source (light to be irradiated) The product of the spot area of b and the thickness of the photosensitive layer was 18,750 μm ³ ), and an image output test and a multi-sheet durability test were conducted using a modified full-color laser copying machine CLC500 manufactured by Canon Inc.

Evaluation was performed in the same manner as in Example 1. As a result, a change in the density of 220 or more gray levels was observed for the 256-tone test pattern, and the amount of scraping of the photoconductor after running 50,000 sheets was 1.1 μm. Although inferior to Example 1, it exhibited excellent durability performance. There were no image defects such as black spots. The transfer efficiency of the toner was as high as 93%. Table 3 summarizes the obtained results.

<Example 6> The above-mentioned carrier 3 and toner 1 were mixed at a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was −26.0 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm and a semiconductor laser having a spot area of 1,250 μm ² on the photosensitive member as an exposure light source (light to be irradiated) The product of the spot area of b and the thickness of the photosensitive layer was 18,750 μm ³ ), and an image output test and a multi-sheet durability test were conducted using a modified full-color laser copying machine CLC500 manufactured by Canon Inc.

When evaluation was performed in exactly the same manner as in Example 1, a change in the density of 220 or more gray levels was observed for the 256-tone test pattern, and the abrasion amount of the photoreceptor after running 50,000 sheets was 0.9 μm. Although inferior to Example 1, it exhibited excellent durability performance. There were no image defects such as black spots. The transfer efficiency of the toner was as high as 94%. Table 3 summarizes the obtained results.

<Comparative Example 1> The above-mentioned carrier 2 and toner 5 were mixed at a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was −25.0 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member C having a photosensitive layer thickness of 27 μm and a semiconductor laser having a spot area of 900 μm ² on the photosensitive member as an exposure light source. The product of the spot area and the thickness of the photosensitive layer was 24,300 μm ³ ), and a full color laser copying machine CLC500 manufactured by Canon Inc. was incorporated therein.

When the evaluation was performed in the same manner as in Example 1, only a density change of less than 200 gradations was obtained for the 256 gradation test pattern, and the gradation reproducibility was lower than the results of Examples 1 to 6. Inferior results. The abrasion loss of the photoreceptor after the endurance of 50,000 sheets was 0.5 μm or less, and the durability performance was excellent. The transfer efficiency of the toner was 80%. Table 3 summarizes the obtained results.

<Comparative Example 2> The above-mentioned carrier 2 and toner 6 were mixed at a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was -22.3 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm and a semiconductor laser having a spot area of 1,250 μm ² on the photosensitive member as an exposure light source (light to be irradiated) The product of the spot area of b and the thickness of the photosensitive layer was 18,750 μm ³ ), and an image output test and a multi-sheet durability test were conducted using a modified full-color laser copying machine CLC500 manufactured by Canon Inc.

When evaluation was performed in the same manner as in Example 1, only a density change of less than 200 tones was obtained for a test pattern of 256 tones, and the tone reproducibility was lower than that of Examples 1 to 6. Inferior results. The abrasion amount of the photoreceptor after 50,000 sheets of durability was 5.4 μm, and there was a problem in durability performance, and black spots appeared on the image. The transfer efficiency of the toner was 86%. Table 3 summarizes the obtained results.

Comparative Example 3 The above-described carrier 4 and toner 2 were mixed to a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was −25.0 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member C having a photosensitive layer thickness of 27 μm and a semiconductor laser having a spot area of 1,250 μm ² on the photosensitive member as an exposure light source (light to be irradiated) The product of the spot area of b and the thickness of the photosensitive layer was 33,750 μm ³ ), and a full-color laser copying machine CLC500 manufactured by Canon Inc. was incorporated therein.

Evaluation was performed in exactly the same manner as in Example 1. As a result, a density change of less than 200 tones was obtained for a test pattern of 256 tones, and the tone reproducibility was lower than the results of Examples 1 to 6. Inferior results. The abrasion amount of the photosensitive member after the endurance of 50,000 sheets was 0.5 μm or less, and the durability performance was excellent. The transfer efficiency of the toner was 94%. Table 3 summarizes the obtained results.

<Comparative Example 4> The carrier 5 and the toner 2 were mixed at a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was −24.0 μC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm and a semiconductor laser having a spot area of 1,250 μm ² on the photosensitive member as an exposure light source (light to be irradiated) The product of the spot area of b and the thickness of the photosensitive layer was 18,750 μm ³ ), and an image output test and a multi-sheet durability test were conducted using a modified full-color laser copying machine CLC500 manufactured by Canon Inc.

When evaluation was performed in exactly the same manner as in Example 1, a density change of 200 or more gray levels was observed for the 256-tone test pattern. The result was inferior. After the endurance of 50,000 sheets, the photoreceptor abrasion amount is 5.6 μm, and there is a problem in the durability performance.
Black spots appeared on the image. The transfer efficiency of the toner was 94%. Table 3 summarizes the obtained results.

<Comparative Example 5> The carrier 4 and the toner 7 were mixed so as to have a toner concentration of 8% by mass to obtain a two-component developer. The charge amount of the toner was -21.6 µC / g. Then, using the obtained two-component developer, an electrophotographic photosensitive member B having a photosensitive layer thickness of 15 μm and a semiconductor laser having a spot area of 1,250 μm ² on the photosensitive member as an exposure light source (light to be irradiated) The product of the spot area of b and the thickness of the photosensitive layer was 18,750 μm ³ ), and an image output test and a multi-sheet durability test were conducted using a modified full-color laser copying machine CLC500 manufactured by Canon Inc.

Evaluation was performed in exactly the same manner as in Example 1. As a result, a density change of less than 200 tones was obtained for a test pattern of 256 tones, and the tone reproducibility was lower than the results of Examples 1 to 6. Inferior results. The abrasion amount of the photoreceptor after the endurance of 50,000 sheets was 1.5 μm. The transfer efficiency of the toner was 85%. Table 3 summarizes the obtained results.

[0166]

[Table 3]

[0167]

As described above, according to the present invention, a photosensitive material in which the product of the irradiation spot area of the exposure light and the thickness of the photosensitive layer of the electrophotographic photosensitive member is 20,000 μm ³ or less. When a photoreceptor having a small layer thickness is used, by using a two-component developer having a specific toner and a magnetic carrier, the transfer efficiency of the toner is high, and a high-quality image having high resolution and excellent gradation is obtained. There is provided an image forming method which can be stably obtained even in durability.
Further, an image forming method is provided which exhibits excellent durability performance of a photoreceptor despite using a photoreceptor having a thin photosensitive layer thickness.

[Brief description of the drawings]

FIG. 1 shows a relationship between a light intensity distribution, a spot diameter, and a product of a light spot area and a thickness of a photosensitive layer.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yayoi Tazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H005 AA08 AA15 AB03 BA03 BA15 CA15 CA26 CB03 EA05 EA07 FA01 2H068 AA11 FC05 FC08

Claims (14)

[Claims] At least a magnetic carrier and a toner are provided.
Process using two-component developer and conductive support
Charges an electrophotographic photoreceptor having a photosensitive layer provided thereon
Charging step, irradiating the charged electrophotographic photosensitive member with light
An image forming method having an exposing step.
Carrier has a number average particle size of 5 to 5 in its particle size distribution.
100 μm, which is not more than half the number average particle diameter.
The distribution cumulative value is 20% by number or less, and the carrier
The shape factor SF-1 is in the range of 1.0 to 1.4,
The shape factor SF-2 is in the range of 1.1 to 2.5, and
First, the toner has a weight average particle size in its particle size distribution.
The diameter is 1 to 10 μm, and the number average particle diameter (D₁1)
The cumulative value of the distribution with a diameter of 2 times or less is 20% by number or less, and the weight is
Average particle size (D_Four) Is 10 weight by weight.
% Or less, and the shape factor SF-1 of the toner is 1.0 to 1.0%.
1.4 and the shape factor SF-2 is 1.1.
To 2.5, and the toner constituting the toner.
Particles containing at least a silicon compound on the surface of the toner particles
It has a coating layer formed by the souls being fixed together.
In the above-mentioned exposure step,
The product of the spot area and the thickness of the photosensitive layer on the conductive support is
1,000 to 20,000 μm ^ThreeIs characterized by
Image forming method. 2. The image forming method according to claim 1, wherein the magnetic carrier is formed of a thermosetting binder resin and a metal oxide, and is obtained by a direct polymerization method. 3. The ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms and silicon atoms measured by electron probe microanalysis on the surface of the toner particles constituting the toner is 0.1 to 20. 3. The image forming method according to claim 1, wherein the amount is 0.0% by mass. 4. The method according to claim 1, wherein the ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms, and silicon atoms measured by electron probe microanalysis on the surface of the toner particles constituting the toner is 0.1 to 10. 3. The image forming method according to claim 1, wherein the amount is 0% by mass. 5. The method according to claim 1, wherein the ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms, and silicon atoms on the surface of the toner particles constituting the toner is 0.1 to 4. 3. The image forming method according to claim 1, wherein the amount is 0% by mass. 6. The mass ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms, and silicon atoms measured by electron probe microanalysis on the cross section of the toner particles constituting the toner is 4.0 mass% or less. The image forming method according to claim 1, wherein: 7. The proportion of silicon atoms, based on the total amount of carbon atoms, oxygen atoms, and silicon atoms, measured by electron probe microanalysis on the cross section of the toner particles constituting the toner, is 0.1% by mass or less. The image forming method according to claim 1, wherein: 8. The method according to claim 8, wherein the ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms and silicon atoms on the surface of the toner particles constituting the toner is 0.1 to 20. 0 mass%, and the ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms, and silicon atoms measured by the electron probe microanalysis on the cross section of the toner particles is 4.0 mass% or less. The image forming method according to claim 1. 9. The method according to claim 1, wherein the ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms and silicon atoms measured by electron probe microanalysis on the surface of the toner particles constituting the toner is 0.1 to 10. 0% by mass, and the ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms, and silicon atoms measured by the electron probe microanalysis on the cross section of the toner particles is 0.1% by mass or less. The image forming method according to claim 1. 10. The ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms and silicon atoms measured by electron probe micropartial analysis on the surface of the toner particles constituting the toner is 0.1 to 4. 0% by mass, and the ratio of silicon atoms to the total amount of carbon atoms, oxygen atoms, and silicon atoms measured by the electron probe microanalysis on the cross section of the toner particles is 0.1% by mass or less. The image forming method according to claim 1. 11. The toner according to claim 3, wherein the proportion of silicon atoms on the surface of the toner particles on which the coating layer is provided is at least twice the proportion of silicon atoms on the cross section of the toner particles.
0. The image forming method according to any one of 0. 12. The image forming method according to claim 3, wherein the coating layer formed on the surface of the toner particles is formed by a polycondensate of a silicon compound. 13. The image forming method according to claim 12, wherein the polycondensate of the silicon compound is formed by a sol-gel method. 14. The image forming method according to claim 12, wherein the coating layer is in a state in which granular lumps containing a polycondensate of a silicon compound are chemically bonded to each other.