JP2016110052A - Image formation device, process cartridge, and image formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a development device with which it is possible to obtain a clear image free of image defects in a low-temperature low-humidity environment, and to obtain an excellent image in a long period of use.SOLUTION: A contact type charging roller 46 rotates in forward relative to an electrostatic latent image carrier and has a tip speed ratio of 105% to 140% inclusive. The contact type charging roller has a shaft core, an elastic layer, and a surface layer on the outer circumference of the elastic layer, the universal hardness of the surface layer being 1.0 N/mmto 17.0 N/mminclusive. A toner has a binder resin, toner particles containing a colorant, and inorganic particulates, the primary particle number average particle diameter (D1) of the inorganic particulates being 50 nm to 500 nm inclusive, the toner having the inorganic particulates for 0.1 pt.mass to 1.0 pt.mass inclusive per toner particles 100 pts.mass, the adhering rate of the inorganic particulates to the toner being 50 mass% to 90 mass% inclusive.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus, a process cartridge, and an image forming method using electrophotography.

  In recent years, printers and copiers have shifted from analog to digital, and have excellent reproducibility of latent images and high resolution.

  Conventionally, printers are connected to a network and are often used to print by a large number of people. Recently, however, there is an increasing demand for printing by hand with a PC and a printer on a personal desk. For this purpose, it is necessary to save the printer space, and there is a strong demand for downsizing the printer.

  In addition, even such a compact printer has high image quality, and there is a great demand for high stability with little fluctuation during long-term use.

  Here, focusing on downsizing of the printer, the downsizing of the fixing unit and the downsizing of the developing device are mainly effective for downsizing. In particular, the latter occupies a considerable part of the volume of the printer, and it can be said that downsizing of the developing device is essential for downsizing of the printer.

  Considering the development method, there are two-component development and one-component development methods as printer development methods, but in the sense of compactness, one-component development is suitable. This is because a member such as a carrier is not used.

  As a developing device, a cleanerless system is very suitable for downsizing. In many printers, the toner on the electrostatic latent image carrier remaining in the transfer process (hereinafter referred to as residual toner) is scraped off by a cleaning blade or the like and collected in a cleaner container. On the other hand, since the cleanerless system does not have a cleaning blade and a cleaner container, the developing device can be greatly reduced in size.

  However, there are also challenges specific to cleanerless systems. For example, impurities such as paper powder, scraping powder of members, and toner agglomerates adhere or fuse to the electrostatic latent image carrier. A fused material grows with these impurities as nuclei. When the fused material grows, when the electrostatic latent image carrier is charged by the charging roller, a charging failure occurs and an image defect occurs.

  In a developing device having a conventional cleaning blade, the above-described impurities are scraped off by the cleaning blade and stored in a cleaner container.

  For such a problem, for example, the charging roller has a conductive foam member and contacts the surface of the image carrier with a difference in peripheral speed. Furthermore, it has a porous surface that holds the conductive particles movably at the contact portion with the surface of the image carrier. Furthermore, there is a report that charging unevenness can be eliminated by using a one-component developer containing conductive particles in an amount of 0.1% by mass to 10% by mass with respect to the toner weight (see Patent Document 1).

  There is also a report that the image flow can be eliminated by providing a difference in peripheral speed between the electrostatic latent image carrier and the polishing roller and the toner having abrasive particles (see Patent Document 2).

  However, even if these developing devices and toners are used, the effect on the image defects due to the impurities as described above is still insufficient. In particular, in a low-temperature and low-humidity environment, the adhesion between the deposit and the electrostatic latent image carrier tends to be improved, and image defects tend to occur.

JP 2003-233254 A JP-A-10-333349

  An object of the present invention is to provide an image forming apparatus capable of stably obtaining a good image even in a low temperature and low humidity environment.

  Another object of the present invention is to provide a process cartridge capable of stably forming a high-quality image even in a low temperature and low humidity environment.

  Still another object of the present invention is to provide an image forming method for stably forming a high-quality image even in a low temperature and low humidity environment.

According to one aspect of the present invention, an electrostatic latent image carrier, a contact-type charging roller that charges the electrostatic latent image carrier, and the surface of the charged electrostatic latent image carrier are irradiated with image exposure light. Image exposing means for forming an electrostatic latent image on the surface of the electrostatic latent image carrier, and developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier to develop the electrostatic latent image. A developing device having a developing means for forming a toner image on the surface of the image carrier; a transfer material for transferring the toner image formed on the surface of the electrostatic latent image carrier with or without an intermediate transfer member A transfer means for transferring the toner image to the transfer material; and a fixing means for fixing the toner image transferred to the transfer material to the transfer material, on the downstream side of the transfer means and on the upstream side of the contact-type charging roller. , Does not include a cleaning means for removing unnecessary toner on the electrostatic latent image carrier,
In the image forming apparatus for collecting the transfer residual toner after transferring the toner image by the developing device,
The developing device includes a toner for developing the electrostatic latent image, a toner carrier for carrying the toner, and a regulating member for regulating the layer thickness of the toner carried on the toner carrier. And the toner carrier is disposed in contact with the electrostatic latent image carrier, the contact-type charging roller rotates in the forward direction with respect to the electrostatic latent image carrier, and the peripheral speed ratio is 105%. The contact-type charging roller has a shaft core body, an elastic layer, and a surface layer on the outer periphery of the elastic layer, and the universal hardness of the surface layer is 1.0 N / mm ² or more and 17. 0 N / mm ² or less,
The toner is a toner having toner particles and inorganic fine particles containing a binder resin and a colorant;
The inorganic fine particles have a primary particle number average particle size (D1) of 50 nm or more and 500 nm or less, and the toner contains 0.1 to 1.0 parts by mass of the inorganic fine particles with respect to 100 parts by mass of the toner particles. An image forming apparatus is provided in which the toner has a fixing ratio of the inorganic fine particles of 50% by mass or more and 90% by mass or less.

Further, the present invention rotates in the forward direction with a peripheral speed difference of 105% or more and 140% or less at a contact position between the electrostatic latent image carrier and the electrostatic latent image carrier. A process cartridge comprising a charging roller for charging an image carrier and a developing device having a toner that also serves as a cleaning device for the surface of the electrostatic latent image carrier, and is configured to be detachable from the image forming apparatus. There,
Universal hardness of the surface layer of the charging roller is at 1.0 N / mm ² or more 17.0 N / mm ² or less,
The toner includes toner particles containing a binder resin and a colorant, and inorganic fine particles, and the inorganic fine particles have a number average particle size (D1) of primary particles of 50 nm or more and 500 nm or less. The inorganic fine particles are contained in an amount of 0.1 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the particles, and the fixing ratio of the inorganic fine particles is 50% by mass or more and 90% by mass or less To a process cartridge.

Furthermore, the present invention relates to an electrostatic latent image carrier, a contact-type charging roller that charges the electrostatic latent image carrier, and a surface of the charged electrostatic latent image carrier that is irradiated with image exposure light. Image exposing means for forming an electrostatic latent image on the surface of the electrostatic latent image carrier, and developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier to A developing step for developing by a developing device having a developing means for forming a toner image on the surface;
A transfer step for transferring the toner image formed on the surface of the latent electrostatic image bearing member to a transfer material with or without an intermediate transfer member; and the toner image transferred to the transfer material. Having a fixing step for fixing to the transfer material;
There is no cleaning step for removing unnecessary toner on the electrostatic latent image carrier on the downstream side of the transfer material and the upstream side of the contact-type charging roller, and the transfer after transferring the toner image In the image forming method of collecting residual toner with the developing device,
The developing device includes a toner for developing the electrostatic latent image, a toner carrier for carrying the toner, and a regulating member for regulating the layer thickness of the toner carried on the toner carrier. And the toner carrier is disposed in contact with the electrostatic latent image carrier, the contact-type charging roller rotates in the forward direction with respect to the electrostatic latent image carrier, and the peripheral speed ratio is 105%. The contact-type charging roller has a shaft core body, an elastic layer, and a surface layer on the outer periphery of the elastic layer, and the universal hardness of the surface layer is 1.0 N / mm ² or more and 17. 0 N / mm ² or less,
The toner is a toner having toner particles and inorganic fine particles containing a binder resin and a colorant;
The inorganic fine particles have a number average particle diameter (D1) of primary particles of 50 nm or more and 500 nm or less,
The toner has 0.1 to 1.0 parts by mass of the inorganic fine particles with respect to 100 parts by mass of the toner particles, and the toner has a fixing rate of 50 to 90% by mass of the inorganic fine particles. The present invention relates to an image forming method characterized by the following.

  By using the developing device having the specific configuration of the present invention, a clear image free from image defects can be obtained in a low temperature and low humidity environment, and a good image can be obtained even in long-term use.

It is a schematic diagram which shows an example of the mixing processing apparatus which can be used for the external addition mixing of inorganic fine particles. It is a schematic diagram which shows an example of a structure of the stirring member used for a mixing processing apparatus. FIG. 3 is a schematic diagram illustrating an embodiment of a toner carrier according to the present invention. FIG. 2 is a schematic cross-sectional view illustrating an example of a developing device of the present invention. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus in which a developing device of the present invention is incorporated. It is a typical sectional view showing other examples of the development device of the present invention. It is explanatory drawing of four area | regions which concern on the number of inorganic fine particles. It is an example of the measurement data of the weight reference | standard particle size distribution half value width of a large particle size silica particle. It is sectional drawing which shows an example of the developing device which concerns on this invention. 1 is an example in which a process cartridge according to an embodiment of the present invention is used in an image forming apparatus.

The present invention includes an electrostatic latent image carrier, a contact-type charging roller that charges the electrostatic latent image carrier, and the surface of the charged electrostatic latent image carrier by irradiating image exposure light to the electrostatic latent image carrier. Image exposure means for forming an electrostatic latent image on the surface of the image carrier, and developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier to develop the surface of the electrostatic latent image carrier A developing device having a developing means for forming a toner image on the surface; for transferring the toner image formed on the surface of the latent electrostatic image bearing member to a transfer material with or without an intermediate transfer member A transfer unit; and a fixing unit for fixing the toner image transferred to the transfer material to the transfer material. The electrostatic latent image is provided downstream of the transfer unit and upstream of the contact-type charging roller. There is no cleaning means for removing unnecessary toner on the image carrier, and the toner remaining after transfer of the toner image is transferred. In the image forming apparatus recovered by the developing device,
The developing device includes a toner for developing the electrostatic latent image, a toner carrier for carrying the toner, and a regulating member for regulating the layer thickness of the toner carried on the toner carrier. And the toner carrier is disposed in contact with the electrostatic latent image carrier, the contact-type charging roller rotates in the forward direction with respect to the electrostatic latent image carrier, and the peripheral speed ratio is 105%. The contact-type charging roller has a shaft core body, an elastic layer, and a surface layer on the outer periphery of the elastic layer, and the universal hardness of the surface layer is 1.0 N / mm ² or more and 17. 0 N / mm ² or less,
The toner is a toner having toner particles and inorganic fine particles containing a binder resin and a colorant;
The inorganic fine particles have a primary particle number average particle size (D1) of 50 nm or more and 500 nm or less, and the toner contains 0.1 to 1.0 parts by mass of the inorganic fine particles with respect to 100 parts by mass of the toner particles. The toner relates to an image forming apparatus in which the fixing ratio of the inorganic fine particles is 50% by mass or more and 90% by mass or less.

The present inventors have conducted a detailed study, the contact type charging roller universal hardness of the surface layer is 1.0 N / mm ² or more 17.0 N / mm ² or less, but to the electrostatic latent image bearing member Inorganic fine particles that rotate in the forward direction, have a peripheral speed ratio of 105% or more and 140% or less, and have a number average particle diameter (D1) of primary particles of 50 nm or more and 500 nm or less are 0% with respect to 100 parts by mass of toner particles. By using a toner having 1 to 1.0 parts by mass and an inorganic fine particle fixing rate of 50 to 90% by mass, a clear image free from image defects can be obtained in a low-temperature and low-humidity environment. I found that I can do it.

  In order to suppress the adhesion or fusion of impurities such as paper dust, scraping powder of members, agglomerates of toner, etc. onto the electrostatic latent image carrier, and the growth of the fused material, impurities must be electrostatically steadily applied. Scrap off the latent image carrier. Further, it is necessary to recover the toner to the developing device via the toner carrier or to transfer it onto the medium at the time of transfer.

  In order to steadily scrape impurities from the electrostatic latent image carrier, the present inventors diligently studied, and it was effective to carry toner on a contact-type charging roller. Details are described below.

<Charging roller>
The charging roller according to the present invention has a two-layer configuration in which a core metal, an elastic layer provided on the outer periphery thereof, and a surface layer are disposed outside the elastic layer.

<Elastic layer>
The elastic layer according to the present invention includes a rubber component.

  The rubber component is not particularly limited, and rubbers known in the field of electrophotographic conductive members can be used. Specifically, epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer, acrylonitrile-butadiene copolymer, acrylonitrile-butadiene copolymer hydrogenated product, silicone Examples thereof include rubber, acrylic rubber, and urethane rubber.

<Surface layer>
The surface layer can contain a resin known in the field of electrophotographic conductive members.

  Specific examples include resins such as acrylic resin, polyurethane, polyamide, polyester, polyolefin, and silicone resin.

  If necessary, the surface layer is made of conductive oxide such as carbon black, graphite, tin oxide, etc., metal such as copper, silver, etc. Ionic conductive agents having ion exchange performance such as conductive particles and quaternary ammonium salts can be further contained.

As a standard of the electric resistance value of the charging roller according to the present invention, it is 1 × 10 ⁶ Ω · cm or more and 1 × 10 ¹⁴ Ω · cm or less, respectively. In particular, the electric resistance value of the charging roller according to the present invention is preferably 1 × 10 ⁹ Ω · cm to 1 × 10 ¹² Ω · cm.

When the electric resistance value of the charging roller according to the present invention is 1 × 10 ⁹ Ω · cm or more, the increase in the downstream discharge amount becomes significant. As a result, the toner can be negatively charged by using the downstream discharge for the toner after passing through the charging roller. Further, by setting the electric resistance value of the charging roller of the present invention to 1 × 10 ¹² Ω · cm or less, it is possible to suppress the occurrence of image defects due to insufficient electric resistance.

  The charging roller according to the present invention needs to be in contact with the electrostatic latent image carrier. This is because the charging roller can come into contact with the electrostatic latent image carrier to exhibit scraping properties. Further, the contact-type charging roller needs to rotate in the forward direction with respect to the electrostatic latent image carrier, and the peripheral speed ratio needs to be 105% or more and 140% or less. By providing a peripheral speed difference in the forward direction, the toner of the present invention described later can be present in the nip portion between the electrostatic latent image carrier and the charging roller, and the toner present in the nip portion can scrape impurities. This is because When the peripheral speed ratio is 105% or more, the scraping property is expressed. If the peripheral speed ratio is 140% or less, uneven charging is less likely to occur. Note that if the contact-type charging roller rotates in the reverse direction with respect to the electrostatic latent image carrier, it becomes difficult to stay in the nip portion between the electrostatic latent image carrier and the charging roller, so that the scraping property is lowered.

The forward direction means that the moving direction of the surface of the charging roller and the surface of the image carrier is the same at the contact portion between the charging roller and the image carrier. The peripheral speed ratio is a ratio of the speed vr of the charging roller surface and the surface speed vd of the image carrier at the contact portion between the charging roller and the image carrier, specifically,
Peripheral speed ratio (%) = vr / vd × 100
It is.

In order to express the scraping property, the charging roller has a shaft core, an elastic layer, and a surface layer on the outer periphery of the elastic layer, and it is necessary to control the universal hardness of the surface layer. Universal hardness of at 1.0 N / mm ² or more 17.0 N / mm ² or less, preferably 1.0 N / mm ² or more 10.0 N / mm ² or less. When the universal hardness is 1.0 N / mm ² or more, the nip portion between the electrostatic latent image carrier and the charging roller can be pressurized, and the scraping property is improved. On the other hand, when the universal hardness is 17.0 N / mm ² or less, since the toner does not take an excessive share, the toner is not cracked, impurities such as cracked toner are hardly generated, and image defects are not easily generated. Become. Further, when the universal hardness is 10.0 or less, the share of the toner can be further suppressed.

The universal hardness of the surface of the charging roller is measured by using, for example, a universal hardness meter (trade name: ultra-micro hardness meter H-100V, manufactured by Fisher). Universal hardness is a physical property value obtained by pushing an indenter into a measurement object while applying a load, and is obtained as (test load) / (surface area of the indenter under the test load) (N / mm ² ). . The indenter such as a quadrangular pyramid is pushed into the object to be measured while applying a predetermined relatively small test load, and the surface area in contact with the indenter is obtained from the indentation depth when the predetermined indentation depth is reached. The universal hardness is obtained from the equation. In the present invention, the hardness when the indenter is pushed in by 1.0 μm is defined as universal hardness.

  The universal hardness of the charging roller according to the present invention can be achieved by controlling the hardness of the surface layer. In the present invention, the surface layer may be softened. The softening of the surface layer can be achieved, for example, by reducing the crosslink density, and a polyurethane resin is suitable because the crosslink density can be easily controlled. Examples of the polyurethane resin suitable for the present invention include polyether-based polyurethane, polycarbonate-based polyurethane, polyester-based polyurethane, and polyolefin-based polyurethane. Since the above-mentioned polyurethane resin has high flexibility of the material itself, it is possible to easily reduce the universal hardness in combination with the reduction of the crosslinking density.

  One of the features according to an embodiment of the present invention is that toner exists in the nip portion between the electrostatic latent image carrier and the charging roller, and the toner exhibits scraping properties. In order for the toner to exhibit better scraping properties, it is preferable that the charging roller and the toner move together to scrape impurities on the electrostatic latent image carrier. In order for the charging roller and the toner to move together better, it is preferable that the surface of the charging roller has a convex portion. By having the convex portion on the surface of the charging roller, the charging roller and the toner are brought together better, and a further excellent scraping property can be expressed.

  Moreover, it is preferable that this convex part originates in the electroconductive particle which exists with resin (binder resin) in the surface layer of a charging roller. By making the convex portion derived from conductive particles, even when the charging roller is used for a long period of time, it becomes difficult to cause uneven charging due to discharge deterioration, and excellent image quality can be maintained over a long period of time.

  In order to form the convex part derived from the above-mentioned conductive particles, conductive particles having a number average particle diameter of 10 nm or more and 100 nm or less are contained in a resin as a binder which is one component of the surface layer. preferable. By setting the number average particle diameter of the conductive particles to 10 nm or more, a convex portion derived from the conductive particles can be more reliably formed on the surface of the charging roller, so that the toner is better brought along. The scraping property is more easily expressed. In addition, when the number average particle diameter is 100 nm or less, unevenness is less likely to occur during charging, and thus image quality is easily improved.

Furthermore, controlling the quantity of the convex portions is also effective for further improving the scraping property. The number of convex portions derived from the exposed portions of the conductive fine particles is preferably 50 or more and 500 or less in a 2.0 μm vertical and 2.0 μm horizontal region (4.0 μm ² region). By setting the number to 50 or more, the toner can be adequately rotated and the scraping property is further improved. Further, by setting the number to 500 or less, it is possible to effectively reduce the load on the toner.

  Next, a method for exposing the conductive fine particles to the surface of the surface layer of the present invention and forming convex portions derived from the conductive fine particles will be described.

  When a surface layer is formed on the conductive elastic layer of the conductive member by dipping coating, a skin layer is always formed on the outermost surface of the surface layer, so that conductive fine particles are not exposed on the surface of the surface layer. The effect of injecting electrons into the soiled material cannot be sufficiently obtained. In order for at least a part of the conductive fine particles to be exposed on the surface of the surface layer and for the exposed portion to form a convex portion on the surface of the surface layer, it is necessary to remove the outermost skin layer. For example, by performing ultraviolet treatment, polishing method, electrolytic polishing method, chemical polishing method, ion milling method, etc., it is possible to remove the surface skin layer of the binder resin and expose the conductive fine particles to the surface of the surface layer. Become. In the present invention, since the hardness of the surface layer is low, it is possible to sufficiently remove the skin layer and expose the conductive fine particles to the surface of the surface layer even by performing ultraviolet treatment. The ultraviolet treatment is preferable because the conductive fine particles can be exposed to the surface of the surface layer while minimizing damage to the surface layer as compared with a polishing method or the like.

  The exposed state of the conductive fine particles can be confirmed using an electron force microscope (AFM). A height image is acquired in the AFM tapping mode. In this case, the part originating in the exposed part of electroconductive fine particles is confirmed as a convex part. When a height image is acquired in the state where the skin layer after dip coating is present, the convex portion is not confirmed. Further, a phase image is acquired in the AFM tapping mode. In this case, there is little phase shift of the conductive fine particles, and an image having a very large contrast between light and shade is obtained due to the difference in hardness between the binder resin and the conductive fine particles. When a phase image is acquired in a state where a skin layer after dip coating exists, an image with a very small phase difference and a low contrast difference is acquired.

  As a method for measuring the convex size, a scanning electron microscope (SEM) may be used to take an image of an arbitrary 2 μm square region, and the size of the conductive point may be calculated from the binarized image.

In the present invention, it is important to control the number of convex portions within a preferable range in order to use the convex portions derived from the conductive fine particles and inject charges into the dirt substance. The number of minute convex portions derived from the exposed portions of the conductive fine particles is preferably 50 or more and 500 or less in a 2.0 μm vertical and 2.0 μm horizontal region (4.0 μm ² region). By setting the number to 50 or more, it is possible to secure the number of convex portions as a starting point for injecting charges into the dirt substance. Further, by making the number 500 or less, it is possible to suppress the injection of charges into the photoreceptor. The number of convex portions can be calculated by taking an image of an arbitrary 2 μm square region using a scanning electron microscope (SEM) and calculating the number of conductive points from the binarized image. .

  Examples of the conductive fine particles include metal oxide conductive particles such as carbon black, titanium oxide, tin oxide, and zinc oxide, and metal conductive particles such as aluminum, iron, copper, and silver. These conductive particles can be used alone or in combination of two or more. Moreover, the composite particle which coat | covered the silica particle with the electroconductive particle can also be used as electroconductive particle. Carbon black is preferred as the conductive fine particles used for the surface layer. Since carbon black has a low specific gravity and high electrical conductivity, it is possible to ensure sufficient electrical conductivity as a surface layer by adding a small amount to the binder resin. The present invention is suitable because it is necessary to keep the hardness of the surface layer low.

  Next, the toner will be described.

  The toner is a toner having toner particles containing a binder resin and a colorant and inorganic fine particles, and the inorganic fine particles have a number average particle diameter (D1) of primary particles of 50 nm to 500 nm.

  In the present invention, the toner needs to have inorganic fine particles in order for the toner to exhibit the scraping property at the nip portion between the electrostatic latent image carrier and the charging roller. It is presumed that the toner has inorganic fine particles so that the inorganic fine particles on the toner surface can scrape impurities.

  When the number average particle diameter (D1) of the primary particles of the inorganic fine particles is 50 nm or more, it becomes possible to scrape impurities such as paper powder, scraped powder of members, toner aggregates, and the like. Further, when the number average particle diameter (D1) of the primary particles of the inorganic fine particles is 500 nm or less, the fixing rate of the inorganic fine particles described later can be improved, and the scraping property is improved by the inorganic fine particles fixed to the toner. .

  In addition, it is important that the toner of the present invention has 0.1 to 1.0 parts by mass of inorganic fine particles with respect to 100 parts by mass of toner particles. When the inorganic fine particles are contained in an amount of 0.1 part by mass or more, the frequency of the inorganic fine particles present on the toner surface is increased, and thus the scraping property is improved.

  On the other hand, when the inorganic fine particles are 1.0 part by mass or less, the fixing rate of inorganic fine particles described later can be improved. By improving the fixing amount, the inorganic fine particles that easily come off from the toner are reduced, so that it becomes easy to prevent the charging roller from being contaminated by the inorganic fine particles that are out of the toner, and the charging unevenness due to the charging roller can be suppressed. .

  In the toner according to the present invention, the fixing ratio of the inorganic fine particles is 50% by mass or more and 90% by mass or less. As described above, in order for the toner to exhibit the scraping property at the nip portion between the electrostatic latent image carrier and the charging roller, the toner needs to have inorganic fine particles. If the toner has only inorganic fine particles, the scraping property is not sufficiently developed, and the inorganic fine particles adhere to the toner, so that the scraping property can be expressed. This is because the inorganic external additive does not come off from the toner due to the energy received when the impurities on the electrostatic latent image carrier are scraped off, and the impurities adhered or fused on the electrostatic latent image carrier are scraped off. I guess there is. When the fixing ratio of the inorganic fine particles is 50% by mass or more, the abundance of the inorganic fine particles firmly fixed to the toner increases, so that the scraping property is improved and image defects can be suppressed. When the adhesion rate of the inorganic fine particles is 90% by mass or less, the inorganic fine particles are less likely to be buried from the toner surface, so that the scraping property is improved.

  This is because, in order to firmly fix the inorganic fine particles to the toner, for example, if a large processing energy is excessively applied in the external addition step of the inorganic fine particles, the fixing rate of the inorganic fine particles is improved, but the embedding also occurs. . Therefore, the adhesion rate of the inorganic fine particles is 90% by mass or less.

  Further, in order to suppress image defects even in a low temperature and low humidity environment, it is a particularly important item to increase the adhesion rate of inorganic fine particles. In a low-temperature and low-humidity environment, the toner charge amount tends to increase. In addition, when the adhesion rate of the inorganic fine particles is low, there are inorganic fine particles that are out of the toner, and their charge amount tends to increase. Therefore, in a low-temperature and low-humidity environment, the inorganic fine particles present on the toner surface are more likely to be lowered in a toner having a low adhesion rate of inorganic fine particles, and the frequency of the inorganic fine particles present on the toner surface is reduced. To do. Therefore, it is important to increase the adhesion rate of inorganic fine particles.

  In addition, since the charge amount of the inorganic fine particles removed from the toner tends to be high, the inorganic fine particles are likely to adhere to the charging roller and the electrostatic latent image carrier, and the charging unevenness and the origin of impurities on the electrostatic latent image carrier are caused. Sometimes it becomes.

  The inorganic fine particle is preferably an oxide containing at least one metal selected from magnesium, aluminum, and titanium. Such a metal oxide is preferable because the hardness of the inorganic fine particles is increased, the scraping property is improved, and image defects are less likely to occur.

  Examples of the oxide containing at least one metal of magnesium, aluminum, and titanium include aluminum oxide, titanium oxide, magnesium oxide, barium titanate, aluminum titanate, magnesium titanate, calcium titanate, and titanium. Examples include strontium acid.

  Among these, strontium titanate is preferably used.

  Moreover, it is preferable that the shape of the inorganic fine particles has a cubic shape or a rectangular parallelepiped shape. When it has a cubic or rectangular parallelepiped shape, for example, when inorganic fine particles are externally added to the toner particles, the inorganic fine particles are easily fixed to the toner particles, so that the fixation rate can be improved. In addition, when the toner scrapes off impurities on the electrostatic latent image carrier, the inorganic fine particles have either a cubic shape or a rectangular parallelepiped shape, so that the scraping property is improved and image defects are easily suppressed. .

  Strontium titanate having a perovskite crystal structure is more preferably used as an oxide containing at least one metal of magnesium, aluminum, and titanium having a cubic or rectangular parallelepiped shape.

  Strontium titanate having a cubic or rectangular parallelepiped shape and a perovskite crystal structure is produced mainly in an aqueous medium without going through a sintering step. For this reason, since it is easy to control to a uniform particle size, it is preferably used in the present invention. That is, such strontium titanate can adhere to the toner more uniformly and stay on the toner particle surface in a state where it is difficult to be detached. Further, when the toner scrapes off impurities on the electrostatic latent image carrier, the scraping property is easily improved.

  In order to confirm that the crystal structure is a perovskite type (face-centered cubic lattice composed of three different elements), it can be confirmed by performing X-ray diffraction measurement.

  In the toner according to the present invention, it is more preferable that not only the fixing rate of inorganic fine particles but also the inorganic fine particles are uniformly diffused. The definition indicating that the inorganic fine particles are uniformly diffused includes four regions (see FIG. 7) defined as follows in the reflected electron image of the toner surface photographed using a scanning electron microscope. , It can be expressed by the average abundance of inorganic fine particles in each region.

  Definition of area: In a reflected electron image of toner, a string that gives the maximum length is a line segment A, and two straight lines that are parallel to the line segment A and 1.5 μm apart from the line segment A are a straight line B and a straight line C. A straight line passing through the midpoint of the line segment A and orthogonal to the line segment A is defined as a straight line D, parallel to the straight line D, and two straight lines separated from the straight line D by 1.5 μm are a straight line E and a straight line F. And Four regions that are squares with a side length of 1.5 μm formed by the line segment A and straight lines B, C, D, E, and F.

  In the four regions thus defined, it is preferable that the average abundance of inorganic fine particles in each region is 1.5 area% or more and 15.0 area% or less.

  When the average abundance of the inorganic fine particles is 1.5 area% or more, the scraping property of the toner is improved at the nip portion between the electrostatic latent image carrier and the charging roller, and image defects are easily suppressed. When the average abundance of the inorganic fine particles is 15.0 area% or less, the chargeability of the toner can be easily controlled, and the image quality is easily improved.

  In addition, it is preferable that the coefficient of variation of the number of inorganic particles in the four regions in the reflected electron image of the toner surface taken using the scanning electron microscope is 0.5 or less.

  When the coefficient of variation is 0.5 or less, the inorganic fine particles are uniformly present on the toner surface, and the scraping property of the toner is improved at the nip portion between the electrostatic latent image carrier and the charging roller. It becomes easy to suppress defects.

  In order to adjust the coefficient of variation of the average abundance and number of inorganic fine particles as described above, the external addition device, the external addition order with other inorganic fine particles, the external addition strength, the external addition time, etc. are adjusted. It can be controlled by externally adding simultaneously with the large particle size silica particles.

  In particular, the device to be externally added and the order of external addition are important. An example is shown below.

  First, after externally adding inorganic fine particles and large-diameter silica particles using an external additive mixing apparatus having high diffusion and pulverization ability, small-diameter silica particles are externally added using the apparatus shown in FIG. Examples of the externally added mixing apparatus having high diffusion and pulverization ability include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer, each of which is preferably used. By externally adding in such an apparatus and order, it becomes easy to adjust the average abundance and variation coefficient (diffusion) of the inorganic fine particles.

  This is because the inorganic fine particles and the large particle size silica particles are less likely to be loosened due to the influence of the shape and the particle size, compared to the small particle size silica particles. Therefore, by first externally adding toner particles, inorganic fine particles, and large particle size silica particles, the inorganic fine particles and large particle size silica particles are likely to be sheared, and the inorganic fine particles and large particle size silica particles are easily loosened.

  On the other hand, when inorganic particles and large-sized silica particles are externally added after externally adding small-sized silica particles to the toner particles, the flowability is low because the small-sized silica particles are externally added to the toner fine particles. The present inventors have inferred that this is because it becomes difficult to share the inorganic fine particles and the large particle size silica particles, and it becomes difficult to loosen the inorganic fine particles and the large particle size silica particles.

  The number average particle size (D1) of the primary particles of the large particle size silica particles is preferably 80 nm or more and 200 nm or less from the viewpoint of controlling the fixing rate and diffusibility of the inorganic fine particles.

  Further, in the large particle size silica particles, the half width of the peak of the primary particles in the weight-based particle size distribution chart is preferably 25 nm or less.

  Thus, the sol-gel method is preferable as a method for obtaining large-diameter silica particles having a small half-value width.

  However, even sol-gel silica obtained by the sol-gel method exists in a spherical and monodisperse form, but there are also some that are united. When the half width is 25 nm or less, the number of such coalesced particles is small, the uniform adhesion of the large-diameter silica particles on the surface of the toner particles is increased, and higher fluidity can be obtained. As a result, the sticking rate and diffusibility of the inorganic fine particles can be easily controlled.

  Next, a method for producing large-diameter silica particles by the sol-gel method will be described below.

  First, a silica sol suspension is obtained by hydrolyzing and condensing alkoxysilane with a catalyst in an organic solvent in which water is present. Then, the solvent is removed from the silica sol suspension and dried to obtain silica fine particles. The number average particle size of the primary particles of large silica particles by the sol-gel method should be controlled by the reaction temperature in the hydrolysis / condensation reaction process, the dripping rate of alkoxysilane, the weight ratio of water, organic solvent and catalyst, and the stirring rate. Is possible. For example, the higher the reaction temperature, the smaller the number average particle size of the primary particles of the large silica particles by the sol-gel method.

  The large particle size silica particles obtained by the sol-gel method thus obtained are usually hydrophilic and have many surface silanol groups. Therefore, when used as an external additive for toner, the silica fine particles are preferably subjected to a hydrophobic treatment on the surface.

  Hydrophobic treatment methods include removing the solvent from the silica sol suspension and drying it, followed by treatment with the hydrophobizing agent, and adding the hydrophobizing agent directly to the silica sol suspension. The method of processing simultaneously with drying is mentioned. From the viewpoint of controlling the half-value width of the particle size distribution and controlling the saturated water adsorption amount, a method of directly adding a hydrophobizing agent to the silica sol suspension is preferable.

  Hydrophobic treatment in suspension allows the sol-gel silica to remain in a monodispersed state, making it possible to apply a hydrophobization treatment, so that agglomerates are less likely to form after drying and a uniform coating is possible. .

  Further, the pH of the silica sol-gel suspension is more preferably acidic. By making the suspension acidic, the reactivity with the hydrophobizing agent is increased, and a stronger and more uniform hydrophobizing treatment can be performed.

  Examples of the hydrophobizing agent include the following. γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ -Aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyl Trimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, methyltriethoxysilane, butyltriethoxysilane, hexyltriethoxysilane, octyl lithoate Xylsilane, decyltriethoxysilane, dodecyltriethoxysilane, phenyltriethoxysilane, o-methylphenyltriethoxysilane, p-methylphenyltriethoxysilane.

  Furthermore, in order to easily disperse the large particle size silica particles on the surface of the toner particles or to exhibit a stable spacer effect, the large particle size silica particles may be crushed.

  The large particle size silica particles preferably have an apparent density of 150 g / L or more and 300 g / L or less. The apparent density of the large particle size silica particles is in the above range, which indicates that the small particle size silica particles are not densely packed and exist with a lot of air between the fine particles, and the apparent density is very low. ing. For this reason, the mixing property of the toner particles and the large particle size silica particles is improved during the external addition step, and a uniform coating state is easily obtained.

  As a means for controlling the apparent density of the large-diameter silica particles within the above range, the adjustment of the strength of the hydrophobization treatment in the silica sol suspension or the crushing treatment after the hydrophobization treatment, the hydrophobization treatment amount, etc. To adjust. By performing a uniform hydrophobization treatment, relatively large aggregates themselves can be reduced. Alternatively, by adjusting the strength of the crushing treatment, relatively large aggregates contained in the silica fine particles after drying can be loosened into relatively small secondary particles, and the apparent density can be reduced. is there.

  Here, the addition amount of the large particle size silica particles is preferably 0.1 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the toner particles. When the addition amount of the large particle size silica particles is within the above range, the coverage rate, the fixation rate, and the diffusion state can be easily controlled.

Particularly preferably, the small-diameter silica particles are fine particles produced by vapor phase oxidation of a silicon halogen compound, and are referred to as dry process silica or fumed silica. For example, it utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

  In this production process, it is possible to obtain composite fine particles of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride or titanium chloride together with silicon halogen compounds.

  As for the particle diameter of the small silica particle, the number average particle diameter (D1) of the primary particles is preferably 5 nm or more and 20 nm or less. More preferably, it is 7 nm or more and 15 nm or less.

  When the particle size of the small silica particles is in the above range, it is preferable to easily control the average abundance ratio and the coefficient of variation.

  In the present invention, the number average particle diameter (D1) of the primary particles of the small-sized silica particles can be measured with a scanning electron microscope by magnifying the silica particles alone before externally adding them to the toner. After external addition to the toner, the surface of the toner is enlarged and observed. At this time, the number average particle diameter (D1) of the primary particles is obtained by measuring and averaging the particle diameters of at least 300 silica fine particles.

  Further, the small particle size silica particles produced by vapor phase oxidation of a silicon halogen compound are more preferably treated silica fine particles having a hydrophobic surface. The treated silica fine particles are particularly preferably those obtained by treating the silica fine particles so that the degree of hydrophobicity measured by a methanol titration test is in the range of 30-80.

  Examples of the hydrophobic treatment method include a method of chemically treating with an organosilicon compound and / or silicone oil that reacts or physically adsorbs with silica fine particles. A preferred method is a method of chemically treating silica fine particles produced by vapor phase oxidation of a silicon halogen compound with an organosilicon compound.

  Examples of the organosilicon compound include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, and bromomethyl. Dimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, Diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divirtetramethyldisiloxane, 1,3 -Diphenyltetramethyldisiloxane and dimethylpolysiloxane having 2 to 12 siloxane units per molecule and one hydroxyl group on the terminal unit Si. These are used alone or in a mixture of two or more.

  In addition, aminopropyltrimethoxysilane having nitrogen atom, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, monobutylaminopropyl Trimethoxysilano, dioctylaminopropyldimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ-propylbenzylamine Such silane coupling agents may be used alone or in combination. A preferred silane coupling agent is hexamethyldisilazane (HMDS).

The silicone oil preferably has a viscosity at 25 ° C. of 0.5 to 10000 mm ² / S, more preferably 1 to 1000 mm ² / S, and still more preferably 10 to 200 mm ² / S. Specific examples include dimethyl silicone oil, methyl fell silicone oil, α-methyl styrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil.

  As a method for treating silicone oil, for example, silica fine particles treated with a silane coupling agent and silicone oil are directly mixed using a mixer such as a Henschel mixer; silicone oil is sprayed on the silica fine particles as a base. Or a method in which silicone oil is dissolved or dispersed in a suitable solvent and then silica fine particles are added and mixed to remove the solvent.

  The silica fine particles treated with silicone oil are more preferably heated to 200 ° C. or higher (more preferably 250 ° C. or higher) in an inert gas to stabilize the surface coating after the silicone oil treatment.

  The treatment amount of the silicone oil is preferably 1 to 40 parts by mass, preferably 3 to 35 parts by mass with respect to 100 parts by mass of silica fine particles, and good hydrophobicity is easily obtained.

Silica fine particles used in the present invention, in order to impart good fluidity to the toner, the specific surface area measured by the BET method by nitrogen adsorption is preferred in the 350 meters ² / g range 20 m ² / g. More preferably, the silica fine particles are those having a hydrophobicity of 25 m ² / g to 300 m ² / g.

  The specific surface area by nitrogen adsorption measured by the BET method is measured according to JIS Z8830 (2001). As a measuring device, an “automatic specific surface area / pore distribution measuring device TriStar 3000 (manufactured by Shimadzu Corporation)” which employs a gas adsorption method by a constant volume method as a measuring method is used.

  The small-diameter silica particles preferably have an apparent density of 15 g / L or more and 50 g / L or less. More preferably, the apparent density of the silica fine particles of 20 g / L or more and 40 g / L or less is in the above range is that the silica fine particles C are hardly densely packed and exist with a lot of air between the fine particles. Is very low. For this reason, even in the toner, since the toner is less likely to be clogged closely, the deterioration rate can be significantly reduced.

  As a means for controlling the apparent density of the small particle size silica particles within the above range, adjustment of the particle size of the silica raw material used for the small particle size silica particles and the strength of the crushing treatment performed before, during or during the above-described hydrophobization treatment , And adjusting the amount of silicone oil treated. By reducing the particle size of the silica raw material, the BET specific surface area of the obtained small particle size silica particles is increased and a large amount of air can be interposed, so that the apparent density can be reduced. Further, by performing the crushing treatment, relatively large aggregates contained in the small particle size silica particles can be loosened into relatively small secondary particles, and the apparent density can be reduced.

  As the mixing treatment device for externally mixing the small particle size silica particles, a known mixing treatment device can be used, but FIG. 1 shows that the coverage and diffusion state of the small particle size silica particles can be easily controlled. An apparatus as shown is preferred.

  FIG. 1 is a schematic view showing an example of a mixing treatment apparatus that can be used when externally mixing small-diameter silica particles used in the present invention.

  Since the mixing treatment apparatus has a configuration in which a share is obtained in a narrow clearance portion with respect to the toner particles and the small particle size silica particles, the small particle size silica particles are loosened from the secondary particles to the primary particles. And can adhere to the surface of the toner particles.

  Further, as described later, in the axial direction of the rotating body, the toner particles and the small-diameter silica particles are easily circulated, and the coverage and the diffusion state are within a preferable range in that the toner particles and the small-diameter silica particles are easily mixed sufficiently before the fixation proceeds. Easy to control.

  On the other hand, FIG. 2 is a schematic diagram showing an example of a configuration of a stirring member used in the mixing treatment apparatus.

  Hereafter, the external addition mixing process of the said small particle size silica particle is demonstrated using FIG.1 and FIG.2.

  The mixing treatment apparatus for externally mixing the small-diameter silica particles includes a rotating body 2 having at least a plurality of stirring members 3 installed on the surface, a drive unit 8 that rotationally drives the rotating body, and a gap between the stirring member 3 and And a main body casing 1 provided.

  The clearance (clearance) between the inner peripheral portion of the main body casing 1 and the stirring member 3 gives the toner particles a uniform share and loosens the small-diameter silica particles from the secondary particles to the primary particles, while on the toner particle surfaces. In order to facilitate adhesion, it is important to keep it constant and minute.

  Further, in this apparatus, the diameter of the inner peripheral portion of the main body casing 1 is not more than twice the diameter of the outer peripheral portion of the rotating body 2. In FIG. 1, an example in which the diameter of the inner peripheral portion of the main casing 1 is 1.7 times the diameter of the outer peripheral portion of the rotating body 2 (the diameter of the body portion obtained by removing the stirring member 3 from the rotating body 2). If the diameter of the inner peripheral portion of the main body casing 1 is less than or equal to twice the diameter of the outer peripheral portion of the rotating body 2, the processing space in which the force acts on the toner particles is appropriately limited. A sufficient impact force is applied to the small silica particles.

  It is important to adjust the clearance according to the size of the main casing. Setting the diameter of the inner peripheral portion of the main casing 1 to about 1% or more and 5% or less is important in terms of applying a sufficient share to the small-diameter silica particles. Specifically, when the diameter of the inner peripheral part of the main body casing 1 is about 130 mm, the clearance is about 2 mm or more and about 5 mm or less. When the diameter of the inner peripheral part of the main body casing 1 is about 800 mm, the clearance is about 10 mm or more and 30 mm or less. It should be about.

  In the external addition mixing step of the small particle size silica particles in the present invention, the mixing unit is used to rotate the rotating body 2 by the drive unit 8 and stir the toner particles and the small particle size silica particles charged into the mixing unit. By mixing, the surface of the toner particles is externally added and mixed with small-diameter silica particles.

  As shown in FIG. 2, at least a part of the plurality of stirring members 3 sends toner particles and small-diameter silica particles in one axial direction of the rotating body as the rotating body 2 rotates. 3a is formed. Further, at least a part of the plurality of stirring members 3 is formed as a return stirring member 3b that returns the toner particles and the small-diameter silica particles to the other direction in the axial direction of the rotating body 2 as the rotating body 2 rotates. ing. Here, when the raw material inlet 5 and the product outlet 6 are provided at both ends of the main casing 1 as shown in FIG. 1, the direction from the raw material inlet 5 toward the product outlet 6 (in FIG. 1). (Right direction) is called “feed direction”.

  That is, as shown in FIG. 2, the plate surface of the feeding stirring member 3a is inclined so as to feed the toner particles in the feeding direction (13). On the other hand, the plate surface of the stirring member 3b is inclined so as to send the toner particles and the small particle size silica particles in the return direction (12). Thus, the external addition mixing process of silica fine particles is performed on the surface of the toner particles while repeatedly performing the feeding (13) in the “feeding direction” and the feeding (12) in the “returning direction”. The stirring members 3a and 3b are a set of a plurality of members arranged at intervals in the circumferential direction of the rotating body 2. In the example shown in FIG. 2, the stirring members 3a and 3b form a pair of two members on the rotating body 2 at an interval of 180 degrees, but three members at an interval of 120 degrees or an interval of 90 degrees. It is good also as a set of many members, such as four sheets.

  In the example shown in FIG. 2, a total of 12 stirring members 3a and 3b are formed at equal intervals.

  Further, in FIG. 2, D indicates the width of the stirring member, and d indicates the interval indicating the overlapping portion of the stirring member. From the viewpoint of efficiently feeding the toner particles and the small-diameter silica particles in the feeding direction and the returning direction, it is preferable that D is a width of about 20% to 30% with respect to the length of the rotating body 2 in FIG. . FIG. 2 shows an example of 23%. Furthermore, it is preferable that the stirring members 3a and 3b have some overlap d between the stirring member 3b and the stirring member when an extension line is drawn in the vertical direction from the end position of the stirring member 3a. As a result, it is possible to efficiently share the silica fine particles that are secondary particles. D is preferably 10% or more and 30% or less in terms of applying a share.

  Regarding the shape of the blade, in addition to the shape shown in FIG. 2, if the toner particles can be sent in the feeding direction and the returning direction and the clearance can be maintained, the shape having a curved surface and the tip blade portion are A paddle structure coupled to the rotating body 2 with a rod-like arm may be used.

  Hereinafter, the present invention will be described in more detail with reference to the schematic views of the apparatus shown in FIGS.

  The apparatus shown in FIG. 1 includes a rotating body 2 having at least a plurality of stirring members 3 installed on the surface, a drive unit 8 that rotationally drives the rotating body 2, and a main casing provided with a gap between the stirring member 3 and the main body casing. 1 Furthermore, it has the jacket 4 which can exist in the inner side of the main body casing 1, and the rotary body end part side surface 10, and can let a cooling medium flow.

  Furthermore, the apparatus shown in FIG. 1 is used to discharge the toner added to the raw material inlet 5 formed in the upper part of the main casing 1 and the externally mixed toner from the main casing 1 in order to introduce toner particles and silica fine particles. In addition, it has a product outlet 6 formed in the lower part of the main casing 1.

  Furthermore, in the apparatus shown in FIG. 1, a raw material inlet inner piece 16 is inserted into the raw material inlet 5, and a product outlet inner piece 17 is inserted into the product outlet 6.

  In the present invention, first, the raw material inlet inner piece 16 is taken out from the raw material inlet 5, and the toner particles are put into the processing space 9 from the raw material inlet 5. Next, silica fine particles are introduced into the treatment space 9 from the raw material inlet 5, and the raw material inlet inner piece 16 is inserted. Next, the rotating body 2 is rotated by the drive unit 8 (11 indicates the direction of rotation), and the processed material introduced above is externally added while being stirred and mixed by a plurality of stirring members 3 provided on the surface of the rotating body 2. Mix.

  The order of charging may be such that the silica fine particles are first charged from the raw material charging port 5 and then the toner particles are charged from the raw material charging port 5. Further, after the toner particles and the small-diameter silica particles are mixed in advance by a mixer such as a Henschel mixer, the mixture may be charged from the raw material charging port 5 of the apparatus shown in FIG.

  It is preferable to control the power of the drive unit 8 to be 0.2 W / g or more and 2.0 W / g or less as the external additive mixing treatment condition in order to improve the coverage and diffusibility. Moreover, it is more preferable to control the power of the drive unit 8 to 0.6 W / g or more and 1.6 W / g or less. When the power is lower than 0.2 W / g, the coverage is difficult to increase, and the diffusibility tends to decrease. On the other hand, when it is higher than 2.0 W / g, although the diffusibility is easy to improve, the small particle size silica particles tend to be embedded too much.

  Although it does not specifically limit as processing time, Preferably it is 3 to 10 minutes. When the treatment time is shorter than 3 minutes, the coverage and diffusibility tend to be low.

The number of rotations of the stirring member during external addition mixing is not particularly limited. In the apparatus in which the volume of the processing space 9 of the apparatus shown in FIG. 1 is 2.0 × 10 ⁻³ m ³ , the rotation speed of the stirring member when the shape of the stirring member 3 is as shown in FIG. 2 is 800 rpm or more and 3000 rpm. The following is preferable. It becomes easy to control a coverage and a diffusion state by being 800 rpm or more and 3000 rpm or less.

  Further, in the present invention, a particularly preferable treatment method is to give each of the small-diameter silica particles a pre-mixing step before the external addition mixing operation. By including the pre-mixing step, the silica particles having a small particle diameter are highly uniformly dispersed on the surface of the toner particles, so that the coverage is easily increased and the diffusion state is easily controlled. More specifically, as premixing processing conditions, the power of the drive unit 8 is set to 0.06 W / g or more and 0.20 W / g or less, and the processing time is set to 0.5 minutes or more and 1.5 minutes or less. preferable. If the load power is lower than 0.06 W / g or the processing time is shorter than 0.5 minutes as the premixing processing condition, sufficient uniform mixing is difficult to perform as premixing. On the other hand, if the load power is higher than 0.20 W / g or the processing time is longer than 1.5 minutes as the pre-mixing processing conditions, a small particle size silica is formed on the surface of the toner particles before sufficient uniform mixing. In some cases, the particles are fixed.

Regarding the rotational speed of the stirring member in the pre-mixing process, when the volume of the processing space 9 of the apparatus shown in FIG. 1 is 2.0 × 10 ⁻³ m ³ and the shape of the stirring member 3 is as shown in FIG. The rotation speed of the stirring member is preferably 50 rpm or more and 500 rpm or less. It becomes easy to control a coverage and a diffusion state by being 50 rpm or more and 500 rpm or less.

  After completion of the external addition mixing process, the product discharge port inner piece 17 is taken out from the product discharge port 6, the rotating body 2 is rotated by the drive unit 8, and the toner is discharged from the product discharge port 6. From the obtained toner, coarse particles and the like are separated by a sieve such as a circular vibration sieve as necessary to obtain a toner.

  The toner of the present invention can also be obtained by a pulverization method. Examples of the binder resin for the toner preferably used in the production by the pulverization method include a vinyl resin, a polyester resin, an epoxy resin, and a polyurethane resin. It does not specifically limit and these conventionally well-known resin can be used. Among these, it is preferable to contain a polyester resin or a vinyl resin from the viewpoint of achieving both chargeability and fixability.

  The composition of the polyester resin is as follows.

  Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1, 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and bisphenol represented by the formula (A) and derivatives thereof;

（式中、Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙ平均値は０〜１０である。）
また（Ｂ）式で示されるジオール類；

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.)
And diols represented by the formula (B);

（ｘ’，ｙ’は、０以上の整数であり、かつ、ｘ＋ｙの平均値は０〜１０である。）
が挙げられる。

(X ′ and y ′ are integers of 0 or more, and the average value of x + y is 0 to 10.)
Is mentioned.

  Examples of the divalent acid component include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or anhydrides thereof, lower alkyl esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid. Acids or anhydrides thereof, lower alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid and n-dodecyl succinic acid, or anhydrides, lower alkyl esters thereof; fumaric acid, maleic acid, citraconic acid, itaconic acid Dicarboxylic acids such as unsaturated dicarboxylic acids or anhydrides thereof, lower alkyl esters;

  In addition, a trivalent or higher alcohol component or a trivalent or higher acid component that functions as a crosslinking component may be used alone or in combination.

  Examples of the trihydric or higher polyhydric alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane. Triol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, etc. Is mentioned.

  Examples of the trivalent or higher polycarboxylic acid component in the present invention include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5, 7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene Carboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, and their anhydrides, lower alkyl esters;

（式中Ｘは炭素数３以上の側鎖を１個以上有する炭素数５〜３０のアルキレン基又はアルケニレン基）
で表わされるテトラカルボン酸等、及びこれらの無水物、低級アルキルエステル等の多価カルボン酸類及びその誘導体が挙げられる。

(Wherein X is an alkylene group or alkenylene group having 5 to 30 carbon atoms having one or more side chains having 3 or more carbon atoms)
And polycarboxylic acids such as anhydrides and lower alkyl esters thereof and derivatives thereof.

  The alcohol component used in the present invention is 40 to 60 mol%, preferably 45 to 55 mol%, and the acid component is 60 to 40 mol%, preferably 55 to 45 mol%.

  The polyester resin is usually obtained by a generally known condensation polymerization.

  In the present invention, a vinyl resin may be contained.

  The following are mentioned as a vinyl-type monomer for producing | generating a vinyl-type resin.

  Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl Styrene such as styrene, pn-butyl styrene, p-tert butyl styrene, pn hexyl styrene, pn octyl styrene, pn nonyl styrene, pn decyl styrene, pn dodecyl styrene and derivatives thereof Styrene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate; Vinyl such as vinyl propionate and vinyl benzoate Stealth; methyl methacrylate, ethyl methacrylate, propyl methacrylate, nbutyl methacrylate, isobutyl methacrylate, n octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylamino methacrylate Α-methylene aliphatic monocarboxylic acid esters such as ethyl and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic Acrylic acid esters such as 2-ethylhexyl acid, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether, vinyl ethyl ether, Vinyl ethers such as vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone Vinyl naphthalenes; and acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

  In addition, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, Unsaturated dibasic acid half esters such as alkenyl succinic acid methyl half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester; dimethyl maleic acid, unsaturated dibasic acid ester such as dimethyl fumaric acid; acrylic acid, Α, β-unsaturated acids such as phosphoric acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic anhydride and cinnamic anhydride, the α, β-unsaturated acids and lower fatty acids And monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.

  Furthermore, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) Monomers having a hydroxy group such as styrene.

  In the toner of the present invention, the vinyl resin of the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. The crosslinking agent used in this case is an aromatic divinyl Examples of the compound include divinylbenzene and divinylnaphthalene; examples of the diacrylate compound linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1 , 5-pentanediol acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylates of the above compounds with methacrylate; di-linked by an alkyl chain containing an ether bond Examples of the acrylate compounds include di Tylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and the above compounds were replaced with methacrylate. Diacrylate compounds entangled with a chain containing an aromatic group and a steric bond include, for example, polyoxyethylene (2) -2,2-bis (4hydroxyphenyl) propane diacrylate, Polyoxyethylene (4) -2,2-bis (4hydroxyphenyl) propane diacrylate, and those obtained by replacing acrylate of the above compound with methacrylate; polyester-type diacrylate compound For example, as a, like the trade name MANDA (Nippon Kayaku) is.

  Examples of the polyfunctional cross-linking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and those obtained by replacing the acrylate of the above compounds with methacrylate; And lucyanurate and triallyl trimellitate.

  These crosslinking agents can be used in an amount of 0.01 to 10 parts by mass (more preferably 0.03 to 5 parts by mass) with respect to 100 parts by mass of other monomer components.

  Among these crosslinkable monomers, those which are preferably used in the binder resin from the viewpoint of fixability and offset resistance are bonded with aromatic divinyl compounds (particularly divinylbenzene), chains containing aromatic groups and ether bonds. And diacrylate compounds.

  Examples of the polymerization initiator used for producing the vinyl copolymer of the present invention include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4- Dimethylvaleronitrile), 2,2′-azobis (-2,4-dimethylvaleronitrile), 2,2′-azopis (-2methylptyronitrile), dimethyl-2,2′-azobisisoptylate, 1,1′-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4- Dimethyl-4-methoxyvaleronitrile, 2,2-azobis (2-methylpropane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclohexane Ketone peroxides such as Sanone peroxide, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroper Oxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide Oxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, diisopropylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, di n-propyl peroxydicarbonate, di-2-engineered tooxyethyl peroxycarbonate, dimethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t- Butyl peroxyacetate, t-butyl peroxyisoptylate, t-butyl peroxyneodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxylaurate, t-butyl perokine Benzoate, t-butylperoxyisopropyl carbonate, di-t-butylperoxyisophthalate, t-butylperoxyallyl carbonate, t-amylperoxy 2-ethylhexanoate, di-t-butylperoxyhexahydride Terephthalate, di -t- butyl peroxy azelate and the like.

  The binder resin according to the present invention has a glass transition temperature (Tg) of 45 to 70 ° C., preferably 50 to 70 ° C., from the viewpoint that it is easy to achieve both low-temperature fixability and storage stability. When Tg is less than 45 ° C., storage stability tends to deteriorate, and when Tg is higher than 70 ° C., low-temperature fixability tends to deteriorate, which is not preferable.

  The toner of the present invention contains a colorant. Examples of the colorant preferably used in the present invention include the following.

  Examples of organic pigments or organic dyes as cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

  Examples of the organic pigment or organic dye as the magenta colorant include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds.

  Examples of the organic pigment or organic dye as the yellow colorant include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

  Examples of the black colorant include carbon black, the above-described yellow colorant, magenta colorant, and cyan colorant that are toned to black.

  When using a colorant, it is preferably used by adding 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer or binder resin.

  The toner of the present invention can also contain a magnetic material. In the present invention, the magnetic material can also serve as a colorant.

  Examples of the magnetic material used in the present invention include iron oxides such as magnetite, maghemite, and ferrite; metals such as iron, cobalt, and nickel, or these metals aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, Examples include alloys of metals such as beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These magnetic materials have a number-based average particle size of 2 μm or less, preferably 0.05 to 0.5 μm. Further, the magnetic characteristics when 795.8 kA / m is applied are coercive force of 1.6 to 12.0 kA / m, saturation magnetization of 50 to 200 Am ² / kg (preferably 50 to 100 Am ² / kg), and residual magnetization of 2 to 20 Am. Those of ² / kg are preferred.

  The magnetic material used in the toner of the present invention can be produced, for example, by the following method.

  An aqueous solution containing ferrous hydroxide is prepared by adding an alkali such as sodium hydroxide in an amount equivalent to or greater than the iron component to the ferrous salt aqueous solution. Air is blown in while maintaining the pH of the prepared aqueous solution at pH 7 or higher, and ferrous hydroxide is oxidized while heating the aqueous solution to 70 ° C. or higher to first produce a seed crystal that becomes the core of magnetic iron oxide. .

  Next, an aqueous solution containing about 1 equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals based on the amount of alkali added previously. While maintaining the pH of the solution at 5 to 10, the reaction of ferrous hydroxide proceeds while blowing air to grow magnetic iron oxide with the seed crystal as the core. At this time, it is possible to control the shape and magnetic characteristics of the magnetic material by selecting an arbitrary pH, reaction temperature, and stirring conditions. As the oxidation reaction proceeds, the pH of the liquid shifts to the acidic side, but the pH of the liquid is preferably not less than 5. A magnetic powder can be obtained by filtering, washing, and drying the magnetic material thus obtained by a conventional method.

  In the present invention, when a toner is produced by a polymerization method, it is very preferable to subject the surface of the magnetic material to a hydrophobic treatment. When surface treatment is performed in a dry process, the coupling agent treatment is performed on the magnetic material that has been washed, filtered, and dried. When wet surface treatment is performed, after the oxidation reaction is completed, the dried product is redispersed, or after the oxidation reaction is completed, the oxidant obtained by washing and filtering is not dried but in another aqueous medium. Re-dispersed and coupled. Specifically, a silane coupling agent is added while stirring the redispersion sufficiently, and the temperature is increased after hydrolysis, or the coupling is performed by adjusting the pH of the dispersion to an alkaline region after hydrolysis. . Among these, from the viewpoint of performing a uniform surface treatment, it is preferable to carry out the surface treatment by reslurry as it is without drying after filtration and washing after completion of the oxidation reaction.

  To wet the surface treatment of the magnetic material, that is, to treat the magnetic material with a coupling agent in an aqueous medium, first, sufficiently disperse the magnetic material in the aqueous medium so as to have a primary particle size, so as not to settle or aggregate. Stir with a stirring blade. Next, an arbitrary amount of coupling agent is added to the dispersion, and the surface treatment is carried out while hydrolyzing the coupling agent. At this time, the dispersion is sufficiently dispersed so as not to aggregate while using a device such as a pin mill or a line mill. More preferably, the surface treatment is carried out.

  Here, the aqueous medium is a medium containing water as a main component. Specific examples include water itself, water added with a small amount of surfactant, water added with a pH adjuster, and water added with an organic solvent. As the surfactant, nonionic surfactants such as polyvinyl alcohol are preferable. The surfactant is preferably added in an amount of 0.1% by mass to 5.0% by mass with respect to water. Examples of the pH adjuster include inorganic acids such as hydrochloric acid. Examples of the organic solvent include alcohols.

Examples of the coupling agent that can be used in the surface treatment of the magnetic material in the present invention include a silane coupling agent and a titanium coupling agent. More preferably used is a silane coupling agent, which is represented by the general formula (I).
RmSiYn (I)
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a functional group such as an alkyl group, a vinyl group, an epoxy group, or a (meth) acryl group, and n represents 1 to 3] Indicates an integer. However, m + n = 4. ]

  Examples of the silane coupling agent represented by the general formula (I) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, Vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyl Diethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, trimethylmethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, hydroxypropyl Examples include trimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.

Among these, from the viewpoint of imparting high hydrophobicity to the magnetic material, it is preferable to use an alkyltrialkoxysilane coupling agent represented by the following general formula (II).
_{C p H 2p + 1 -Si- (} OC q H 2q + 1) 3 (II)
[Wherein, p represents an integer of 2 to 20, and q represents an integer of 1 to 3. ]

  When p in the above formula is 2 or more, it becomes easy to impart hydrophobicity to the magnetic material. Further, when p is 20 or less, the coalescence of the magnetic materials is easily suppressed. Furthermore, q is preferably 3 or less because the reactivity of the silane coupling agent is easily improved. It is preferable to use an alkyltrialkoxysilane coupling agent in which p represents an integer of 2 to 20 and q represents an integer of 1 to 3.

  When using the said silane coupling agent, it is possible to process independently or to process in combination of several types. When using several types together, you may process separately with each coupling agent, and may process simultaneously.

  Moreover, in this invention, it is preferable to add and use a charge control agent. The charging property of the magnetic toner of the present invention may be positive or negative. However, since the binder resin itself has a high negative charging property, it is preferably a negatively charging toner.

  For example, organometallic complexes and chelate compounds are effective as negatively charged ones. Examples thereof include monoazo metal complexes; acetylacetone metal complexes; metal complexes of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids and their metals. Examples thereof include salts, anhydrides, esters, and phenol derivatives such as bisphenol.

  Preferred examples of the charge control agent for negative charging include Spiron Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44, S-54, E-. 84, E-88, E-89 (Orient Chemical).

  Examples of those that are controlled to be positively charged include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and the like. Onium salts such as phosphonium salts and the like, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (as rake agents, phosphotungstic acid, phosphomolybthenic acid, phosphotungstomolybthenic acid, tannic acid, Lauric acid, gallic acid, ferricyanic acid, ferrocyanic compound, etc.); metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyl Rusuzuboreto, be mentioned, such as organo-tin borate of dicyclohexyl tin borate. These can be used alone or in combination of two or more.

  Preferred examples of the charge control agent for positive charging include TP-302, TP-415 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) N-01, N-04, N-07, P-51 (Orient Chemical Co., Ltd.) and Copy Blue PR (Clariant).

  In the present invention, hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax are preferably used as the wax because of ease of dispersion in the toner and high releasability. However, one kind or two or more kinds of waxes may be used in a small amount as required. Examples include the following:

  Oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof; waxes based on fatty acid esters such as carnauba wax, sazol wax, and montanate wax; and deoxidation The fatty acid esters such as carnauba wax may be partially or wholly deoxidized. Further, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, and seryl alcohol Saturated alcohols such as melyl alcohol; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylene bis stearic acid amide, ethylene biscaprin Saturated fatty acid bisamides such as acid amide, ethylene bislauric acid amide, hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl Unsaturated fatty acid amides such as dipinamide, N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylenebisstearic acid amide, N, N-distearylisophthalic acid amide; calcium stearate, laur Grafted with fatty acid metal salts such as calcium phosphate, zinc stearate, magnesium stearate (generally called metal soap), and aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid. Examples of waxes include partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols, and methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils and the like.

  Moreover, it is preferable that melting | fusing point prescribed | regulated by the maximum endothermic peak temperature at the time of temperature rising measured with the differential scanning calorimeter (DSC) of this wax is 70 to 140 degreeC. More preferably, the temperature is 90 to 135 ° C. When the melting point is 70 ° C. or lower, the viscosity of the magnetic toner tends to decrease, and the magnetic toner is likely to be fused to the electrostatic latent image carrier, which is not preferable. On the other hand, when the melting point is 140 ° C. or higher, the low-temperature fixability tends to deteriorate, which is not preferable.

  The “melting point” of the wax is determined by measuring according to ASTM D3418-82 using a differential scanning calorimeter (DSC measuring device), DSC-7 (manufactured by Perkin Elmer). The sample to be measured is precisely weighed 5 to 20 mg, preferably 10 mg.

  This is put in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rise rate of 10 ° C./min at room temperature and normal humidity within a measurement temperature range of 30 to 200 ° C.

  Since the maximum endothermic peak is obtained in the temperature range of 40 to 100 ° C. in the second temperature raising process, the temperature at that time is used as the melting point of the wax.

  The toner of the present invention preferably has a weight average particle diameter (D4) of 5.0 μm to 10.0 μm from the viewpoint of scraping properties at the nip portion between the electrostatic latent image carrier and the charging roller, Preferably, it is 6.0 μm to 9.0 μm.

  In the present invention, the average circularity of the toner particles is preferably 0.960 or more, and more preferably 0.970 or more. When the average circularity of the toner particles is 0.960 or more, the shape of the toner is a sphere or a shape close to this, and it is easy to obtain a uniform triboelectric chargeability with excellent fluidity. Therefore, it is preferable because high developability can be easily maintained even in the latter half of the durability. In addition, toner particles having a high average circularity are preferable because the average abundance ratio and coefficient of variation can be easily controlled within the scope of the present invention in the external addition treatment of inorganic fine particles described later.

  The toner of the present invention can adjust an average abundance ratio and a coefficient of variation, and is not particularly limited in other manufacturing steps as long as it is a manufacturing method having a step of adjusting an average circularity, and is publicly known. It can manufacture by the method of.

  In the case of producing by a pulverization method, for example, a binder resin and a colorant and, if necessary, other additives such as a release agent are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill. Thereafter, the toner material is dispersed or dissolved by using a heat kneader such as a heating roll, a kneader, and an extruder to disperse or dissolve the toner material. After cooling and solidification, pulverization, classification, and if necessary, surface treatment is performed to obtain toner particles. obtain. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

  The pulverization can be performed by a method using a known pulverizer such as a mechanical impact type or a jet type. Further, in order to obtain a toner having a preferable circularity of the present invention, it is preferable to further pulverize by applying heat or to add a mechanical impact force supplementarily. Further, a hot water bath method in which finely pulverized (classified as necessary) toner particles are dispersed in hot water, a method of passing in a hot air stream, or the like may be used.

  Examples of means for applying a mechanical impact force include a method using a mechanical impact pulverizer such as a kryptron system manufactured by Kawasaki Heavy Industries, Ltd. or a turbo mill manufactured by Turbo Industry. Further, there is a method in which a mechanical impact force is applied to the toner by a force such as a compressive force or a frictional force, as in a device such as a mechano-fusion system manufactured by Hosokawa Micron Corporation or a hybridization system manufactured by Nara Machinery Co., Ltd.

  The toner of the present invention can be produced by the pulverization method as described above, but the toner particles obtained are generally indefinite. In the cleanerless image forming apparatus of the present invention, it is very effective to improve the transferability of the toner in order to improve the image quality. For this reason, a toner having a high degree of circularity is preferably used from the viewpoint of transferability. Specifically, the average circularity is preferably 0.960 or more. In order to obtain such a high circularity toner pulverization method, it is necessary to perform mechanical / thermal or some special treatment, resulting in poor productivity. Therefore, the toner of the present invention is preferably produced in an aqueous medium such as a dispersion polymerization method, an association aggregation method, a dissolution suspension method, or a suspension polymerization method. In particular, the suspension polymerization method is a suitable physical property of the present invention. It is easy to satisfy and is very preferable.

  The suspension polymerization method is a polymerizable monomer in which a polymerizable monomer and a colorant (in addition, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives as necessary) are uniformly dissolved or dispersed. A composition is obtained. Thereafter, the polymerizable monomer composition is dispersed in a continuous layer (for example, an aqueous phase) containing a dispersion stabilizer by using a suitable stirrer, and a polymerization reaction is simultaneously performed to obtain a toner having a desired particle size. To get. Since the toner obtained by this suspension polymerization method (hereinafter also referred to as “polymerized toner”) has individual toner particle shapes that are substantially spherical, the physical property requirement suitable for the present invention that the average circularity is 0.960 or more. It is easy to obtain a toner that satisfies the requirements. Furthermore, since the toner has a relatively uniform charge amount distribution, an improvement in image quality can be expected.

  In the production of the polymerized toner particles according to the present invention, known monomers can be used as the polymerizable monomer constituting the polymerizable monomer composition. Among these, styrene or a styrene derivative is preferably used alone or mixed with another polymerizable monomer from the viewpoint of the development characteristics and durability of the toner.

  In the present invention, the polymerization initiator used in the suspension polymerization method preferably has a half-life of 0.5 hours or more and 30.0 hours or less during the polymerization reaction. Moreover, it is preferable that the addition amount of a polymerization initiator is 0.5 to 20.0 mass parts with respect to 100 mass parts of polymerizable monomers.

  Specific examples of the polymerization initiator include azo or diazo polymerization initiators and peroxide polymerization initiators.

  In the suspension polymerization method, a crosslinking agent may be added during the polymerization reaction, and a preferable addition amount is 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. .

  Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used. For example, an aromatic divinyl compound, a carboxylic acid ester having two double bonds, a divinyl compound, and a compound having three or more vinyl groups are used alone or as a mixture of two or more.

  Hereinafter, the production of toner particles by the suspension polymerization method will be specifically described, but the present invention is not limited thereto. First, the above-mentioned polymerizable monomer and coloring agent are added as appropriate, and the polymerizable monomer composition uniformly dissolved or dispersed by a disperser such as a homogenizer, a ball mill, or an ultrasonic disperser is dispersed. Suspend in an aqueous medium containing a stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size all at once. The polymerization initiator may be added at the same time as other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  After granulation, stirring may be performed using a normal stirrer to such an extent that the particle state is maintained and particle floating and sedimentation are prevented.

  As the dispersion stabilizer, known surfactants, organic dispersants, or inorganic dispersants can be used. In particular, inorganic dispersants are less likely to produce harmful ultrafine powders, and because of their steric hindrance, dispersion stability is obtained, so even if the reaction temperature is changed, stability is not easily lost, and washing is easy and does not adversely affect the toner. Therefore, it can be preferably used. Examples of such inorganic dispersants include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, phosphate polyvalent metal salts such as hydroxyapatite, carbonates such as calcium carbonate and magnesium carbonate, calcium metasuccinate, calcium sulfate, Examples thereof include inorganic salts such as barium sulfate and inorganic compounds such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide.

  These inorganic dispersants are preferably used in an amount of 0.20 parts by mass or more and 20.00 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. Moreover, the said dispersion stabilizer may be used independently and may use multiple types together. Furthermore, you may use together 0.0001 mass part or more and 0.1000 mass part or less surfactant with respect to 100 mass parts of polymerizable monomers.

  The polymerization temperature in the polymerization reaction of the polymerizable monomer is set to a temperature of 40 ° C. or higher, generally 50 ° C. or higher and 90 ° C. or lower.

  After the polymerization of the polymerizable monomer is completed, the obtained polymer particles are filtered, washed and dried by a known method to obtain toner particles. The toner of the present invention is obtained by externally mixing and mixing these toner particles with inorganic fine particles, large-diameter silica particles, small-diameter silica particles and the like, and adhering them to the surface of the toner particles.

  It is also possible to add a classification step to the production process (before mixing the inorganic fine particles) to remove coarse powder and fine powder contained in the toner particles.

  Next, a toner carrier used in the image forming apparatus or process cartridge of the present invention will be described.

  The toner carrier used in the present invention has a substrate, an elastic layer, and a surface layer containing a urethane resin, and the urethane resin has a partial structure derived from a reaction between a compound represented by the following structural formula (1) and polyisocyanate. Have.

  One embodiment of the toner carrier according to the present invention is shown in FIG. In the conductive roller 31 (toner carrier) shown in FIG. 3, an elastic layer 33 is formed on the outer peripheral surface of a columnar or hollow cylindrical conductive substrate 32. The surface layer 34 covers the outer peripheral surface of the elastic layer 33.

<Substrate>
The base 32 functions as an electrode and a support member of the conductive roller 31, and is a metal or alloy such as aluminum, copper alloy or stainless steel; iron plated with chromium or nickel; synthetic resin having conductivity It is made of a conductive material such as

<Elastic layer>
The elastic layer 33 gives the conductive roller elasticity necessary for forming a contact portion having a predetermined width at the contact portion between the conductive roller and the electrostatic latent image carrier.

  It is preferable that the elastic layer 33 is usually formed of a molded body of a rubber material. Examples of the rubber material include the following. Ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluorine rubber, Silicone rubber, epichlorohydrin rubber, hydride of NBR, urethane rubber. These can be used alone or in admixture of two or more.

  Among these, silicone rubber is particularly preferable because it does not easily cause compression set in the elastic layer even when other members (such as a developer regulating blade) for a long time come into contact with each other. Examples of the silicone rubber include a cured product of addition-curable silicone rubber. More specifically, a cured product of addition-curable dimethyl silicone rubber is particularly preferable because of excellent adhesion to the surface layer described later.

  In the elastic layer 33, various additives such as a conductivity imparting agent, a non-conductive filler, a crosslinking agent, and a catalyst are appropriately blended. As the conductivity imparting agent, carbon black; conductive metal such as aluminum and copper; fine particles of conductive metal oxide such as zinc oxide, tin oxide and titanium oxide can be used. Of these, carbon black is particularly preferred because it is relatively easy to obtain and provides good conductivity. When carbon black is used as the conductivity-imparting agent, 2 to 50 parts by mass is blended with 100 parts by mass of rubber in the rubber material. Non-conductive fillers include silica, quartz powder, titanium oxide, zinc oxide or calcium carbonate. Examples of the crosslinking agent include di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and dicumyl peroxide. Examples of the catalyst include known catalysts that are usually used.

<Surface layer>
The surface layer 34 is a resin layer containing a urethane resin as a main component. The urethane resin is obtained by a reaction between a polyol and a polyisocyanate, and can be synthesized as follows.

  First, a polyol component such as polyether polyol or polyester polyol is reacted with polyisocyanate to obtain an isocyanate group-terminated prepolymer.

  Subsequently, the urethane resin which concerns on this invention can be obtained by making an isocyanate group terminal prepolymer react with the compound which has a structure of Structural formula (1).

  Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Polyester polyols include 1,4-butanediol, 3-methyl-1,4-pentanediol, diol components such as neopentyl glycol, triol components such as trimethylolpropane, adipic acid, phthalic anhydride, terephthalic acid, A polyester polyol obtained by a condensation reaction with a dicarboxylic acid such as hexahydroxyphthalic acid is exemplified.

  In addition to the above, polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, hydrogenated products thereof, and polycarbonate polyols may be mentioned.

  These polyol components may be prepolymers that are chain-extended with an isocyanate such as 2,4-tolylene diisocyanate (TDI), 1,4-diphenylmethane diisocyanate (MDI), or isophorone diisocyanate (IPDI) as required.

  The number average molecular weight of the polyether polyol and polyester polyol is particularly preferably 1000 or more and 4000 or less. When the number average molecular weight of the polyol is in the above range, the hydroxyl group amount relative to the molecular weight is large, so that the reactivity with isocyanate is high, and the number of unreacted components decreases, so the chargeability in a high temperature and high humidity environment becomes better.

  The isocyanate compound to be reacted with the polyol component and the compound represented by the structural formula (1) is not particularly limited, but aliphatic polyisocyanates such as ethylene diisocyanate and 1,6-hexamethylene diisocyanate (HDI). Isocyanate, isophorone diisocyanate (IPDI), cyclohexane 1,3-diisocyanate, cycloaliphatic polyisocyanate such as cyclohexane 1,4-diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), 4, Aromatic isocyanates such as 4'-diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, copolymers thereof, Cyanurate body, TMP adduct, biuret, can be used the block body.

  Among these, aromatic isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and polymeric diphenylmethane diisocyanate are more preferably used.

  The mixing ratio of the polyol component and the isocyanate compound to be reacted with the compound represented by the structural formula (1) is such that the ratio of the isocyanate group to 1.0 is 2.0 to 2.0 for each hydroxyl group. preferable.

  The surface layer of the toner carrier used in the present invention has a compound represented by the structural formula (1). As described above, the use of this compound can maintain a good rolling property of the toner. It is possible to impart high chargeability to the toner.

  The compound represented by the structural formula (1) will be described in detail. The compound represented by the structural formula (1) represents a polyfunctional polyol or terminal amino compound having an amine structure in the molecule. When n is 1 or more and 4 or less, that is, in the case of a structure having 4 or more and 7 or less hydroxyl groups or amino groups which are reactive functional groups, a crosslinked structure with a urethane group or a urea group is well formed and is microscopic. Hardness is improved. As a result, good rolling properties of the toner can be maintained.

  Next, according to the study by the present inventors, this effect is exhibited when the number of hydroxyl groups or amino groups of the compound represented by the structural formula (1) is 4 or more and 7 or less. Therefore, the number of terminal functional groups of the compound represented by the structural formula (1) may be at least 4, and the same effect can be obtained even if the rest is substituted with an alkyl group.

In the compound represented by the structural formula (1), each R ³ is independently selected from the group consisting of the following (a) to (c).
(A) a hydroxyalkyl group having 2 to 8 carbon atoms (b) an aminoalkyl group having 2 to 8 carbon atoms (c) a group represented by the structural formula (2)

When R ³ is a hydroxyalkyl group, the number of carbon atoms is 1 or more and 8 or less. When R ³ is an aminoalkyl group, the number of carbon atoms is 2 or more and 8 or less. It is easy and preferable.

Structural formula (2) represents a group having a terminal hydroxyl group having a so-called ether repeating unit. When R ³ is a group represented by the structural formula (2), for the same reason, R ⁵ is an alkylene group having 2 to 5 carbon atoms, and the ether repeating number m is 2 to 3 Is preferred.

In the structural formula (1), R ⁴ is preferably an alkylene group having 2 to 4 carbon atoms. When the alkylene group has 2 to 4 carbon atoms, the chargeability of the toner carrier is improved. This is considered to be because when R ⁴ is an alkylene group having 2 or more and 4 or less carbon atoms, the molecule has an appropriate size, so that the dispersibility upon reaction with isocyanate is good.

Among the compounds represented by the structural formula (1), in the compound represented by the structural formula (3), that is, the compound represented by the structural formula (1), n is 1 or 2, and each R ³ independently represents the number of carbon atoms. Particularly preferred is an alkylene group having 2 or 3 carbon atoms, and R ⁴ is particularly preferably an alkylene group having 2 carbon atoms.

  A urethane resin containing a partial structure derived from the structural formula (3) has a functional group value (pentafunctional) and a distance between urethane groups in the most suitable range. Especially preferred.

In Structural Formula (3), n is 1 or 2, R ⁶ is each independently an alkylene group having 2 or 3 carbon atoms, and R ⁷ represents an alkylene group having 2 carbon atoms.

In the present invention, the structure formed by the reaction of the compound represented by the structural formula (1) and the polyisocyanate has a structure in which R ³ is (a) a hydroxyalkyl group having 2 to 8 carbon atoms, or (c ) In the case of the group represented by the structural formula (2), the structure has a urethane group at the terminal of the structural formula (1).

When R ³ is (b) an aminoalkyl group having 1 to 8 carbon atoms, the structure has a urea group at the terminal of the structural formula (1).

  The surface layer 34 preferably has conductivity. Examples of the conductivity imparting means include addition of an ionic conductive agent and conductive fine particles. However, conductive fine particles which are inexpensive and have little resistance fluctuation in the environment are preferably used, and carbon is used from the viewpoint of conductivity imparting and reinforcing properties. Black is particularly preferred. As the properties of the conductive fine particles, a carbon black having a primary particle size of 18 nm or more and 50 nm or less and a DBP oil absorption of 50 ml / 100 g or more and 160 ml / 100 g or less, the balance of conductivity, hardness and dispersibility. Is preferable. It is preferable that the content rate of electroconductive fine particles is 10 to 30 mass% with respect to 100 mass parts of resin components which form a surface layer.

  When the surface roughness is required for the toner carrier, fine particles for controlling the roughness may be added to the surface layer 34. The fine particles for roughness control preferably have a volume average particle size of 3 to 20 μm. Moreover, it is preferable that the particle addition amount added to a surface layer is 1-50 mass parts with respect to 100 mass parts of resin solid content of a surface layer. As fine particles for roughness control, fine particles of polyurethane resin, polyester resin, polyether resin, polyamide resin, acrylic resin, and phenol resin can be used.

  Although it does not specifically limit as a formation method of the surface layer 34, The spray by a coating material, immersion, or a roll coat is mentioned. The dip coating method for overflowing paint from the upper end of the dip tank as described in JP-A-57-5047 is simple and excellent in production stability as a method for forming a surface layer.

  Next, the image forming apparatus and the process cartridge of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these.

  4 and 6 are schematic cross-sectional views showing examples of the developing device used in the image forming apparatus and the process cartridge of the present invention, respectively. FIG. 5 is a schematic cross-sectional view showing an embodiment of an image forming apparatus according to the present invention. FIG. 9 is a schematic sectional view showing a further example of a developing device used in the image forming apparatus and the process cartridge of the present invention. FIG. 10 shows an example in which a process cartridge according to an embodiment of the present invention is used in an image forming apparatus.

  4 or 5, an electrostatic latent image carrier 45, which is an image carrier on which an electrostatic latent image is formed, is rotated in the direction of arrow R1. The toner carrier 47 rotates in the direction of the arrow R2 to convey the toner 57 to the development area where the toner carrier 47 and the electrostatic latent image carrier 45 are opposed to each other. Further, a toner supply member 48 is in contact with the toner carrier, and the toner 57 is supplied to the surface of the toner carrier by rotating in the direction of arrow R3.

  Around the electrostatic latent image carrier 45, a charging roller 46, a transfer member (transfer roller) 50, a fixing device 51, a pickup roller 52, and the like are provided. The electrostatic latent image carrier 45 is charged by the charging roller 46. Then, exposure is performed by irradiating the electrostatic latent image carrier 45 with laser light by the laser generator 54, and an electrostatic latent image corresponding to the target image is formed. The electrostatic latent image on the electrostatic latent image carrier 45 is developed with toner in the developing device 49 to obtain a toner image. The toner image is transferred onto a transfer material (paper) 53 by a transfer member (transfer roller) 50 in contact with the electrostatic latent image carrier 45 via the transfer material. The transfer material (paper) 53 on which the toner image is placed is conveyed to the fixing device 51 and fixed on the transfer material (paper) 53.

  In the charging process in the image forming apparatus of the present invention, the electrostatic latent image carrier and the charging roller form a contact portion to come into contact with each other, and a predetermined charging bias is applied to the charging roller so as to cover the surface of the electrostatic latent image carrier. It is preferable to use a contact charging device that charges to a predetermined polarity / potential. By performing contact charging in this manner, stable and uniform charging can be performed, and generation of ozone can be reduced. It is more preferable to use a charging roller that rotates in the same direction as the electrostatic latent image carrier in order to maintain uniform contact with the electrostatic latent image carrier and perform uniform charging.

  Examples of preferable process conditions when using a charging roller include a contact pressure of the charging roller of 4.9 to 490.0 N / m, and a DC voltage or a DC voltage superimposed with an AC voltage.

  The AC voltage is preferably 0.5 to 5.0 kVpp, the AC frequency is 50 to 5 kHz, and the absolute value of the DC voltage is preferably 400 to 1700V.

  As the material of the charging roller, elastic material such as ethylene-propylene-dienepolyethylene (EPDM), urethane, butadiene acrylonitrile rubber (NBR), silicone rubber, isoprene rubber, etc., carbon black or metal oxide is used for resistance adjustment. Examples thereof include, but are not limited to, rubber materials in which conductive materials such as materials are dispersed, and those obtained by foaming these materials. It is also possible to adjust the resistance using an ion conductive material without dispersing the conductive substance or in combination with the conductive substance.

  Examples of the core bar used for the charging roller include aluminum and SUS. The charging roller is disposed in pressure contact with a member to be charged as an electrostatic latent image carrier with a predetermined pressing force against elasticity, and is a contact portion between the charging roller and the electrostatic latent image carrier. A charging contact portion is formed.

  Next, the contact transfer process preferably applied in the image forming apparatus of the present invention will be specifically described. The contact transfer process is to electrostatically transfer the toner image to the recording medium while the electrostatic latent image carrier is in contact with the transfer member to which a voltage having a polarity opposite to that of the toner is applied via the recording medium. The contact pressure of the transfer member is preferably 2.9 N / m or more, more preferably 19.6 N / m or more. If the linear pressure as the contact pressure is less than 2.9 N / m, the conveyance of the recording medium and the transfer failure are likely to occur.

  In the present invention, it is preferable that the thickness of the toner layer on the toner carrier is regulated by the toner regulating member coming into contact with the toner carrier via the toner. By doing so, high image quality without fogging can be obtained. As a toner regulating member that abuts on the toner carrier, a regulating blade is generally used and can be suitably used in the present invention.

  As the regulation blade, a rubber elastic body such as silicone rubber, urethane rubber, NBR; a synthetic resin elastic body such as polyethylene terephthalate; a metal elastic body such as phosphor bronze plate or SUS plate can be used. There may be. Further, a charge control substance such as resin, rubber, metal oxide, or metal is applied to the contact portion of the toner carrier for the purpose of controlling the chargeability of the toner against an elastic support such as rubber, synthetic resin, or metal elastic body. You may use what was attached to. Among these, it is particularly preferable to attach a resin and rubber to the metal elastic body so as to contact the contact portion of the toner carrier.

  As a material of the member to be bonded to the metal elastic body, a material that is easily charged to positive polarity such as urethane rubber, urethane resin, polyamide resin, and nylon resin is preferable.

  The base, which is the upper side of the regulating blade, is fixedly held on the developing device side, and the lower side is bent in the forward or reverse direction of the toner carrier against the elastic force of the blade. With an appropriate elastic pressing force.

  The contact pressure between the regulating blade and the toner carrier is preferably 1.30 to 245.0 N / m, more preferably 4.9 to 118.0 N / m as the linear pressure in the toner carrier bus direction. It is. When the contact pressure is less than 1.30 N / m, it is difficult to uniformly apply the toner, which easily causes fogging and scattering. When the contact pressure exceeds 245.0 N / m, a large pressure is applied to the toner and the toner tends to be easily deteriorated.

The amount of the toner layer on the toner carrying member, it is preferably, more preferably 3.0 g / m ² or more 14.0 g / m ² or less is 2.0 g / m ² or more 15.0 g / m ² or less .

If the toner amount on the toner carrier is less than 2.0 g / m ^2, it is difficult to obtain a sufficient image density. On the other hand, if the amount of toner on the toner carrier is more than 15.0 g / m ² , poor regulation tends to occur, and uniform chargeability tends to be impaired, and fog tends to increase.

  In the present invention, the amount of toner on the toner carrier can be arbitrarily changed by changing the surface roughness (Ra) of the toner carrier, the free length of the regulating blade, and the contact pressure of the regulating blade.

For measuring the amount of toner on the toner carrier, a cylindrical filter paper is attached to a suction port having an outer diameter of 6.5 mm. This is attached to a vacuum cleaner, sucking the toner on the toner carrying member while sucking it, and the value obtained by dividing the sucked toner amount (g) by the sucked area (m ² ) is taken as the toner amount on the toner carrying member.

  In the present invention, the outer diameter of the toner carrier for carrying the toner is preferably 8.0 mm or greater and 14.0 mm or less. In terms of making the developing device more compact, the smaller the outer diameter of the toner carrier, the better. However, the smaller the outer diameter, the easier the developing property to be lowered and the fog tends to deteriorate. For this reason, in the toner carrier and the toner used in the present invention, the outer diameter of the toner carrier is preferably 8.0 mm or greater and 14.0 mm or less in order to achieve both compactness and fog.

  The surface roughness of the toner carrier used in the present invention is preferably in the range of 0.3 μm or more and 5.0 μm or less in terms of the centerline average roughness Ra in the standard of JIS B 0601: 1994 surface roughness. Is 0.5 μm or more and 4.5 μm or less.

  When Ra is 0.3 μm or more and 5.0 μm or less, a sufficient amount of toner can be obtained, the amount of toner on the toner carrying member can be easily regulated, and it is difficult for regulation to occur. It tends to be uniform.

  The measurement of the center line average roughness Ra in accordance with JIS B 0601: 1994 surface roughness standards of the surface of the toner carrier is performed using a surf coder SE-3500 manufactured by Kosaka Laboratory. Measurement conditions were 9 points (3 points in the circumferential direction for each of 3 points equally spaced in the axial direction) at a cutoff of 0.8 mm, an evaluation length of 4 mm, and a feed rate of 0.5 mm / s. And the average value was taken.

  To make the surface roughness of the toner carrier in the present invention within the above range, for example, it is possible to change the polishing state of the surface layer of the toner carrier or to add spherical carbon particles, carbon fine particles, graphite, resin fine particles, etc. It becomes.

  In the present invention, the developing step is preferably a step of forming a toner image by applying a developing bias to the toner carrier and transferring the toner to the electrostatic latent image on the electrostatic latent image carrier. May be a DC voltage or a voltage obtained by superimposing an alternating electric field on the DC voltage.

  As the waveform of the alternating electric field, a sine wave, a rectangular wave, a triangular wave, or the like can be used as appropriate. Further, it may be a pulse wave formed by periodically turning on / off a DC power source. As described above, a bias whose voltage value periodically changes can be used as the waveform of the alternating electric field.

  In the present invention, when a method of conveying toner by magnetism without using a toner supply member is used, it is necessary to dispose a magnet inside the toner carrier (reference numeral 59 in FIG. 6). In this case, the toner carrier preferably has a fixed magnet having multiple poles inside, and preferably has 3 to 10 magnetic poles.

  As a further example of the developing device used for the image forming measure in the present invention, as shown in FIG. 9, the toner supply container 60 having toner causes the toner to be supplied when the developing device runs out or runs out of toner. It is also possible to employ a configuration in which the developer is replenished and the developer is continuously used.

  The process cartridge according to the present invention includes at least a charging roller for charging the electrostatic latent image carrier, an electrostatic latent image carrier, and a developing device having toner, and holds these integrally, and The image forming apparatus is configured to be detachable.

  Furthermore, the driving of the charging roller is configured to receive a driving force from the driving of the electrostatic latent image carrier. Thereby, it is possible to control the surface speed of the charging roller with respect to the surface speed of the electrostatic latent image carrier on the process cartridge. An example of transmitting the drive includes engaging a gear member disposed at the first end of the photoreceptor and a gear member disposed at the first end of the charging roller. In addition, a normal method such as using a belt is possible.

  Furthermore, a modification in which the driving of the charging roller is directly received from the image forming apparatus and transmitted to the electrostatic latent image carrier can be given as an example.

  FIG. 10 shows the process cartridge 61 mounted on the image forming apparatus. The process cartridge 61 integrally holds the electrostatic latent image carrier 45, the charging roller 46, and the developing means 49.

  Next, a method for measuring physical properties of the toner used in the present invention will be described.

<Average particle size and particle size distribution of toner>
The weight average particle diameter (D4) of the toner is calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. Note that the measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, dedicated software was set up as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic aqueous solution is put in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rotations / second. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set in the dedicated software is the weight average particle diameter (D4).

<Measuring method of average circularity of toner particles>
The average circularity of the toner particles is measured by a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.

  A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.2 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by VervoCrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is added, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.

  For the measurement, the above-mentioned flow type particle image analyzer equipped with “UPlanApro” (magnification 10 times, numerical aperture 0.40) as an objective lens is used, and the particle sheath “PSE-900A” (manufactured by Sysmex Corporation) is used as the sheath liquid. It was used. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the circle equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles is obtained.

  In the measurement, automatic focus adjustment is performed using standard latex particles (eg, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific) diluted with ion-exchanged water before starting the measurement. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In the present invention, a flow type particle image measuring apparatus that has been calibrated by Sysmex Corporation and that has been issued a calibration certificate issued by Sysmex Corporation is used. The analysis particle size is measured under the measurement and analysis conditions when the calibration certificate is received, except that the equivalent circle diameter is limited to 1.985 μm or more and less than 39.69 μm.

  The measurement principle of the flow-type particle image measuring device “FPIA-3000” (manufactured by Sysmex Corporation) is to take a flowing particle as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is picked up by a CCD camera, and the picked-up image is image-processed at an image processing resolution of 512 × 512 pixels (0.37 × 0.37 μm per pixel), the contour of each particle image is extracted, and the particle image The projected area S, the peripheral length L, etc. are measured.

Next, the equivalent circle diameter and the circularity are obtained using the area S and the peripheral length L. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity is a value obtained by dividing the circumference of the circle obtained from the equivalent circle diameter by the circumference of the projected particle image. Defined and calculated by the following formula.
Circularity = 2 × (π × S) ^1/2 / L

  When the particle image is circular, the circularity is 1.000. The greater the degree of irregularities on the outer periphery of the particle image, the smaller the circularity. After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is divided into 800, the arithmetic average value of the obtained circularity is calculated, and the value is defined as the average circularity.

<Calculation of average abundance of inorganic fine particles and coefficient of variation of inorganic fine particles>
In the present invention, the calculation is performed by analyzing the toner surface image photographed by Hitachi ultra-high resolution field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation). The image capturing conditions of S-4800 are as follows.

(1) Sample preparation A conductive paste is thinly applied to a sample table (aluminum sample table 15 mm × 6 mm), and toner is sprayed thereon. Further, air is blown to remove excess toner from the sample stage and sufficiently dry. The sample stage is set on the sample holder, and the height of the sample stage is adjusted to 36 mm by the sample height gauge.

(2) S-4800 Observation Condition Setting The average abundance of inorganic fine particles is calculated using an image obtained by S-4800 reflected electron image observation. Since the reflected electron image is less charged up with inorganic fine particles than the secondary electron image, the average abundance can be measured with high accuracy.

  Liquid nitrogen is poured into the anti-contamination trap attached to the S-4800 mirror until it overflows, and is placed for 30 minutes. The “PC-SEM” of S-4800 is activated and flushing (cleaning of the FE chip as an electron source) is performed. Click the acceleration voltage display part of the control panel on the screen and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute. Confirm that the emission current by flashing is 20-40 μA. Insert the sample holder into the sample chamber of the S-4800 mirror. Press [Origin] on the control panel to move the sample holder to the observation position.

  Click the acceleration voltage display section to open the HV setting dialog, and set the acceleration voltage to [0.8 kV] and the emission current to [20 μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE], select [Up (U)] and [+ BSE] for the SE detector, and select [+ BSE] in the selection box on the right. L. A. 100] to select a mode in which observation is performed with a reflected electron image. Similarly, in the [Basic] tab of the operation panel, the probe current of the electron optical system condition block is set to [Normal], the focus mode is set to [UHR], and the WD is set to [3.0 mm]. Press the [ON] button in the acceleration voltage display section of the control panel to apply the acceleration voltage.

(3) Calculation of number average particle diameter (D1) of toner Drag within the magnification display section of the control panel to set the magnification to 5000 (5k). The focus knob [COARSE] on the operation panel is rotated, and the aperture alignment is adjusted when the focus is achieved to some extent. Click [Align] on the control panel to display the alignment dialog and select [Beam]. The STIGMA / ALIGNMENT knob (X, Y) on the operation panel is rotated to move the displayed beam to the center of the concentric circle. Next, [Aperture] is selected, and the STIGMA / ALIGNMENT knobs (X, Y) are turned one by one to stop the movement of the image or adjust the movement to the minimum. Close the aperture dialog and focus with auto focus. Repeat this operation two more times to focus.

  Thereafter, the particle diameter of 300 toner particles is measured to determine the number average particle diameter (D1). The particle diameter of each particle is the maximum diameter when the toner particles are observed.

(4) Focus adjustment For the particles with a number average particle diameter (D1) of ± 0.1 μm obtained in (3), inside the magnification display part of the control panel with the midpoint of the maximum diameter aligned with the center of the measurement screen Drag to set the magnification to 10,000 (10k). The focus knob [COARSE] on the operation panel is rotated, and the aperture alignment is adjusted when the focus is achieved to some extent. Click [Align] on the control panel to display the alignment dialog and select [Beam]. The STIGMA / ALIGNMENT knob (X, Y) on the operation panel is rotated to move the displayed beam to the center of the concentric circle. Next, [Aperture] is selected, and the STIGMA / ALIGNMENT knobs (X, Y) are turned one by one to stop the movement of the image or adjust the movement to the minimum. Close the aperture dialog and focus with auto focus. Thereafter, the magnification is set to 50000 (50k), focus adjustment is performed using the focus knob and the STIGMA / ALIGNMENT knob in the same manner as described above, and the focus is again adjusted by autofocus. Repeat this operation again to focus. Here, since the measurement accuracy of the average abundance ratio tends to be low when the angle of inclination of the observation surface is large, by selecting the one that allows the entire observation surface to be in focus at the same time when adjusting the focus, it is possible to minimize the surface inclination. Select and analyze.

(5) Image storage Brightness adjustment is performed in ABC mode, and a photograph is taken with a size of 640 × 480 pixels and stored. The following analysis is performed using this image file. One photograph is taken for one toner particle, and an image is obtained for at least 30 toner particles.

(6) Image Analysis The reflected electron image on the toner surface is divided into four regions (see FIG. 7) defined as follows and analyzed.
Definition of area: In a reflected electron image of toner, a string that gives the maximum length is a line segment A, and two straight lines that are parallel to the line segment A and 1.5 μm apart from the line segment A are a straight line B and a straight line C. A straight line passing through the midpoint of the line segment A and orthogonal to the line segment A is defined as a straight line D, parallel to the straight line D, and two straight lines separated from the straight line D by 1.5 μm are a straight line E and a straight line F. And Four regions that are squares with a side length of 1.5 μm formed by the line segment A and straight lines B, C, D, E, and F.

In the above four areas,
A region surrounded by the line segment A and the line segments B, D, E is a region K,
A region surrounded by the line segment A and the line segments B, D, and F is a region L,
A region surrounded by the line segment A and the line segments C, D, E is a region M,
A region surrounded by the line segment A and the line segments C, D, and F was defined as a region N.

The number of inorganic fine particles is measured in each region. Here, since some inorganic fine particles exist as aggregates, only those that can be confirmed as primary particles are measured.
Based on the following formula, the abundance ratio in each region of the inorganic fine particles is calculated.
Presence ratio K of inorganic fine particles in region K = (number of inorganic fine particles in region K × area calculated from number average particle size of primary particles of inorganic fine particles / area of region K) × 100 (%)

The abundances L, M, and N of the inorganic fine particles in the regions L, M, and N were calculated in the same manner as the above formula.
Average abundance of inorganic fine particles = Average coefficient of variation of the abundance of the above four regions = (Standard deviation of inorganic fine particles / Average number of inorganic fine particles)
Standard deviation of inorganic fine particles = (dispersion K of inorganic fine particles and the square root of the average of the squares of L, M, and N)
Dispersion K and L, M, N = (Average number of inorganic fine particles-Number of inorganic fine particles present in regions K, L, M, and N)

<Method for measuring number average particle size of primary particles of silica particles and inorganic particles>
The number average particle size of the primary particles of the silica particles and the inorganic fine particles is the fine particles of the silica fine particles and the second group on the surface of the toner imaged by Hitachi Ultra High Resolution Field Emission Scanning Electron Microscope S-4800 (Hitachi High-Technologies Corporation). It is calculated from the titanate child image. The image capturing conditions of S-4800 are as follows.

(1) Sample preparation A conductive paste is thinly applied to a sample table (aluminum sample table 15 mm × 6 mm), and toner is sprayed thereon. Further, air is blown to remove excess toner from the sample stage and sufficiently dry. The sample stage is set on the sample holder, and the height of the sample stage is adjusted to 36 mm by the sample height gauge.

(2) S-4800 observation condition setting The number average particle diameter of the primary particles of silica particles and inorganic fine particles is calculated using an image obtained by the reflected electron image observation of S-4800. Since the reflected electron image has less charge-up than the secondary electron image, the particle size can be measured with high accuracy.

  Liquid nitrogen is poured into the anti-contamination trap attached to the S-4800 mirror until it overflows, and is placed for 30 minutes. S-4800 “PCSTEM” is activated and flushing (cleaning of the FE chip as an electron source) is performed. Click the acceleration voltage display part of the control panel on the screen and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute. Confirm that the emission current by flashing is 20-40 μA. Insert the sample holder into the sample chamber of the S-4800 mirror. Press [Origin] on the control panel to move the sample holder to the observation position.

  Click the acceleration voltage display section to open the HV setting dialog, and set the acceleration voltage to [0.8 kV] and the emission current to [20 μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE], select [Up (U)] and [+ BSE] for the SE detector, and select [+ BSE] in the selection box on the right. L. A. 100] to select a mode in which observation is performed with a reflected electron image. Similarly, in the [Basic] tab of the operation panel, the probe current of the electron optical system condition block is set to [Normal], the focus mode is set to [UHR], and the WD is set to [3.0 mm]. Press the [ON] button in the acceleration voltage display section of the control panel to apply the acceleration voltage.

(3) Calculation of number average particle diameter (D1) of silica particles and inorganic fine particles Drag within the magnification display section of the control panel to set the magnification to 100000 (100k) times. The focus knob [COARSE] on the operation panel is rotated, and the aperture alignment is adjusted when the focus is achieved to some extent. Click [Align] on the control panel to display the alignment dialog and select [Beam]. The STIGMA / ALIGNMENT knob (X, Y) on the operation panel is rotated to move the displayed beam to the center of the concentric circle. Next, [Aperture] is selected, and the STIGMA / ALIGNMENT knobs (X, Y) are turned one by one to stop the movement of the image or adjust the movement to the minimum. Close the aperture dialog and focus with auto focus. Repeat this operation two more times to focus.

  Thereafter, the particle size of at least 300 silica particles and inorganic fine particles on the toner surface is measured to obtain an average particle size. Here, since silica particles and inorganic fine particles may exist as aggregates, the primary particles of silica particles and inorganic fine particles are obtained by calculating the maximum diameter of what can be confirmed as primary particles and arithmetically averaging the obtained maximum diameter. The number average particle diameter (D1) is obtained.

<Measurement method of the adhesion rate of inorganic fine particles>
Preparation of sample Toner before release: Various toners prepared in Examples described later were used as they were.
Toner after release: Weigh 20 g of a 2% by weight aqueous solution of neutral detergent for cleaning a pH7 precision measuring instrument consisting of non-ionic surfactant, anionic surfactant and organic builder in a 50 ml vial. The toner is mixed with 1 g of toner, set in “KM Shaker” (model: V.SX) manufactured by Iwaki Sangyo Co., Ltd., and set to speed 50 and shaken for 30 seconds, and then centrifuged (at 1000 rpm for 5 minutes). The toner and the aqueous solution are separated by separating the supernatant and the precipitated toner is vacuum-dried to dryness.
External additive-removed toner: The external additive-removed toner means a state in which an external additive that can be liberated in this test is removed. In the sample preparation method, the toner is put in a solvent that does not dissolve the toner, such as isopropanol, and vibration is applied for 10 minutes with an ultrasonic cleaner. Thereafter, the toner and the solution are separated by a centrifugal separator (1000 rpm for 5 minutes). The supernatant is separated and the precipitated toner is dried by vacuum drying.

  For the sample before and after the removal of the free external additive, the intensity of the Group 2 element is used by wavelength dispersive X-ray fluorescence analysis (XRF) to determine the titanic acid fine particles and determine how much they have been released. It was.

(I) Example of apparatus used X-ray fluorescence analyzer 3080 (Rigaku Corporation)
Sample press molding machine MAEKAWA Testing Machine (manufactured by MFG Co, LTD)

(Ii) Measurement conditions Measurement potential, voltage 50 kV, 50 to 70 mA
2θ angle a
Crystal plate LiF
Measurement time 60 seconds

(Iii) Calculation Method of Fixing Ratio from Toner Particles First, the element strengths of the pre-release toner, the post-release toner and the external additive-removed toner are obtained by the above method. Thereafter, the liberation rate is calculated based on the following formula.
[Formula] Fixing rate of inorganic fine particles = (strength of inorganic fine particles of toner after release−strength of inorganic fine particles of toner removed from external additive) / (strength of inorganic fine particles of toner before liberation−of inorganic fine particles of toner removed from external additive) (Strength) x 100

<Measurement method of half width of peak in weight-based particle size distribution chart of large particle size silica particles>
The weight-based particle size distribution half-value width of the large particle size silica particles is CPS Instruments Inc. Measurement is performed using a disk centrifugal particle size distribution measuring apparatus DC24000. The measuring method is shown below.

1) In the case of magnetic toner First, 0.5 mg of Triton-X100 (manufactured by Kishida Chemical Co., Ltd.) is added to 100 g of ion exchange water to prepare a dispersion medium. 1 g of toner is added to 9 g of this dispersion medium, and dispersed for 5 minutes by an ultrasonic disperser. Thereafter, the toner particles are constrained using a neodymium magnet to produce a supernatant. Next, a syringe dedicated to a measuring device manufactured by CPS is attached to the tip of an all plastic disposable syringe (Tokyo Glass Instrument Co., Ltd.) equipped with a syringe filter (diameter: 13 mm / pore diameter 0.45 μm) (manufactured by Advantech Toyo Co., Ltd.). Attach a needle and collect 0.1 mL of supernatant. The supernatant liquid collected with a syringe is injected into a disk centrifugal particle size distribution measuring apparatus DC24000, and the weight-based particle size distribution of the large particle diameter silica particles is measured.

  Details of the measurement method are as follows.

  First, the disk is rotated at 24000 rpm with Motor Control on CPS software. Then, the following conditions are set from Procedure Definitions.

(1) Sample parameter
・ Maximum Diameter: 0.5μm
・ Minimum Diameter: 0.05μm
-Particle Density: 2.0-2.2 g / mL (silica density; enter the value for the sample used)
-Particle Refractive Index: 1.43
・ Particle Absorption: 0K
・ Non-Sphericity Factor: 1.1

(2) Calibration Standard Parameters
・ Peak Diameter: 0.226μm
・ Half Height Peak Width: 0.1 μm
・ Particle Density: 1.389 g / mL
・ Fluid Density: 1.059g / mL
-Fluid Refractive Index: 1.369
Fluid Fluidity: 1.1 cps

  After setting the above conditions, CPS Instruments Inc. Using an auto gradient maker AG300, a density gradient solution of 8 mass% sucrose aqueous solution and 24 wt% sucrose aqueous solution is prepared, and 15 mL is injected into the measurement container.

  After the injection, in order to prevent evaporation of the density gradient solution, 1.0 mL of dodecane (manufactured by Kishida Chemical Co., Ltd.) is injected to form an oil film and wait for 30 minutes or more to stabilize the apparatus.

  After waiting, calibration standard particles (weight-based center particle size: 0.226 μm) are injected into the measuring apparatus with a 0.1 mL syringe, and calibration is performed. Thereafter, the collected supernatant is poured into the apparatus, and the weight-based particle size distribution is measured.

  An example of a weight-based particle size distribution chart obtained by measurement is shown in FIG. As shown in FIG. 8, a peak was observed in the region of 80 nm to 200 nm, and the half width of this peak was defined as the half width of the peak of the primary particle in the weight-based particle size distribution chart. Since the lower limit of measurement is 0.05 μm, silica fine particles A are not observed, and in FIG. 8, the peak appearing on the larger particle size side than 200 nm is a peak derived from other externally added particles. .

2) In the case of non-magnetic toner First, 0.5 mg of Triton-X100 (manufactured by Kishida Chemical Co., Ltd.) is added to 100 g of ion-exchanged water to prepare a dispersion medium. To 9.4 g of this dispersion medium, 0.6 g of toner is added and dispersed with an ultrasonic disperser for 5 minutes. Then, a syringe needle dedicated to a measuring device manufactured by CPS is attached to the tip of an all plastic disposable syringe (Tokyo Glass Instrument Co., Ltd.) equipped with a syringe filter (diameter: 13 mm / pore diameter 0.45 μm) (manufactured by Advantech Toyo Co., Ltd.). And 0.1 mL of the supernatant is collected. The supernatant liquid collected by the syringe is injected into a disk centrifugal particle size distribution measuring apparatus DC24000, the weight-based particle size distribution of the large particle diameter silica particles is measured, and the half width of the peak of the primary particles in the chart is obtained. The details of the measurement method are as described above.

<Measurement of the number of convex portions derived from exposed portions of conductive fine particles>
The method for measuring the number of convex portions derived from the exposed portions of the conductive fine particles on the surface layer of the conductive roller is as follows. First, an elastic layer including a surface layer is cut out from the conductive roller, platinum is deposited on the outermost surface of the surface layer, and a vertical 2. using a scanning electron microscope (trade name: S-4800, manufactured by Hitachi High-Technology Corporation). An area of 0 μm × 2.0 μm in width was observed at a magnification of 40000 and photographed. The obtained image was analyzed using image analysis software (trade name: Image-Pro Plus, manufactured by Planetron). Binarization processing was performed on the photographed SEM image, and the number of convex portions was calculated. Five SEM images were taken, and the average value of the calculated number of particles was defined as the number of convex portions derived from the exposed portions of the conductive fine particles of the present invention.

<Measurement of universal hardness>
A universal hardness at a position of 1 μm in depth was measured with a universal hardness meter by pressing the indenter 1 μm from the surface of the surface layer of the conductive roller. The measurement was performed using an ultra-micro hardness meter (trade name: HM-2000, manufactured by Fischer), and the average value of 10 measurements was defined as the hardness of the universe of the present invention. A Vickers indenter was used as the indenter. The indentation speed was determined by the following conditional expression (1). In the formula (1), F is force and t is time.
dF / dt = 1mN / 30s (1)

  The universal hardness at a depth of 1 μm from the surface of the surface layer of the conductive roller was defined as “universal hardness (t = 1 μm position)”.

  Hereinafter, the present invention will be described more specifically with reference to production examples and examples, but these do not limit the present invention in any way. In addition, all the parts in the following mixing | blending show a mass part.

(Production of charging roller)
<Preparation of unvulcanized rubber composition>
The materials of the types and amounts shown in Table 1 below were mixed to prepare an unvulcanized rubber composition.

<Production of conductive elastic roller>
A round bar having a total length of 252 mm and an outer diameter of 6 mm was prepared by subjecting the surface of free-cutting steel to electroless nickel plating. Next, an adhesive was applied over the entire circumference in a range of 230 mm excluding 11 mm at both ends of the round bar. The adhesive used was a conductive hot melt type. A roll coater was used for coating. In this example, a round bar coated with the adhesive was used as a conductive shaft core.

  Next, a crosshead extruder having a conductive shaft core supply mechanism and an unvulcanized rubber roller discharge mechanism is prepared, and a die having an inner diameter of 12.5 mm is attached to the crosshead. The conveyance speed of the conductive shaft core was adjusted to 60 mm / sec. Under these conditions, the unvulcanized rubber composition was supplied from the extruder, and the uncured rubber composition was coated as an elastic layer on the conductive shaft core body in the crosshead to obtain an unvulcanized rubber roller. . Next, the unvulcanized rubber roller was put in a hot air vulcanization furnace at 170 ° C. and heated for 60 minutes to obtain an unpolished conductive elastic roller. Then, the edge part of the elastic layer was excised and removed. Finally, the surface of the elastic layer was polished with a rotating grindstone. As a result, a conductive elastic roller having a diameter of 9.9 mm and a center diameter of 10.0 mm at positions of 90 mm from the central portion to both end sides was obtained.

<Preparation of coating liquid 1>
The binder resin coating solution for forming the conductive layer according to the present invention was prepared by the following method.

  In a reaction vessel under a nitrogen atmosphere, 100 parts of polycarbonate diol (trade name: T5652 (Mn = 2000) manufactured by Asahi Kasei Chemicals Co., Ltd.) are added to 27 parts of polymeric MDI (trade name: Millionate MR200, manufactured by Nippon Polyurethane Industry Co., Ltd.). The inner temperature was gradually dropped while maintaining the temperature at 65 ° C. After completion of the dropping, the reaction was carried out at a temperature of 65 ° C. for 2 hours. The resulting reaction mixture was cooled to room temperature to obtain an isocyanate group-terminated prepolymer 1 having an isocyanate group content of 4.6%.

(Preparation of coating solution 1)
Similarly, 56.9 parts of isocyanate group-terminated prepolymer 1, 36.9 parts of carbonate diol (trade name: T5652 (Mn = 2000) manufactured by Asahi Kasei Chemicals Corporation), carbon black (trade name: MA230 number average particle) 30 nm in diameter, 20.0 parts manufactured by Mitsubishi Chemical Corporation) were mixed with stirring.

  Next, methyl ethyl ketone (hereinafter referred to as MEK) was added so that the total solid content ratio was 30% by mass, and then mixed and stirred for 12 hours in a paint shaker. Subsequently, the coating liquid 1 was prepared by adjusting the viscosity to 8 cps with MEK.

<Manufacture of charging roller>
After dipping the conductive elastic roller prepared above once in the coating liquid 1 prepared by the above method, it is air-dried at 23 ° C. for 30 minutes and then dried in a hot air circulating dryer set at 90 ° C. for 1 hour. The film was further dried for 1 hour in a hot air circulating drier set at 160 ° C. to form a conductive layer on the outer peripheral surface of the conductive elastic roller. The dipping coating dipping time is 9 seconds, the dipping coating lifting speed is adjusted so that the initial speed is 20 mm / sec and the final speed is 2 mm / sec, and the time between 20 mm / sec and 2 mm / sec is linear with respect to time. The speed was changed.

Next, the charging roller produced by the above method is irradiated with ultraviolet light having a wavelength of 254 nm so that the integrated light quantity becomes 9000 mJ / cm ^2, and the binder resin on the outermost surface layer is decomposed to form conductive convex portions. I let you. A low-pressure mercury lamp (manufactured by Harrison Toshiba Lighting) was used for ultraviolet irradiation. The charging roller 1 was manufactured by the above method.

<Charging rollers 2-9>
Charging rollers 2 to 9 were produced in the same manner as the charging roller 1 except that the coating liquid 1 was changed to each coating liquid shown in Table 3. In addition, as raw materials of the coating liquid described in Table 3, (A) hydroxyl group-terminated prepolymer (polyol), (B) isocyanate group-terminated prepolymer (isocyanate), and (C) roughened particles are used in Tables 2-1 to 2- 3. As in Example 1, a part of the isocyanate group-terminated prepolymer was reacted in advance with polyol and polymeric MDI (trade name: Millionate MR200, manufactured by Nippon Polyurethane Industry Co., Ltd.) as shown in Table 2 to obtain an isocyanate group content of 4 What was adjusted to 6% was used.

(Preparation of substrate)
As a substrate (32 in FIG. 3), a SUS304 core metal having a diameter of 6 mm was prepared by applying and baking a primer (trade name, DY35-051; manufactured by Toray Dow Corning).

(Production of elastic roller)
The substrate prepared above was placed in a mold, and an addition type silicone rubber composition in which the following materials were mixed was injected into a cavity formed in the mold.
-100 parts of liquid silicone rubber material (trade name, SE6724A / B; manufactured by Toray Dow Corning)-15 parts of carbon black (trade name, Toka Black # 4300; manufactured by Tokai Carbon Co.)-Silica powder as a heat resistance imparting agent Body 0.2 part / platinum catalyst 0.1 part An addition-type silicone rubber composition in which the materials described in Table 1 above were mixed was poured into a cavity formed in the mold. Subsequently, the mold was heated to cure and cure the silicone rubber at a temperature of 150 ° C. for 15 minutes. The substrate on which the cured silicone rubber layer was formed on the peripheral surface was removed from the mold, and then the substrate was further heated at a temperature of 180 ° C. for 1 hour to complete the curing reaction of the silicone rubber layer. Thus, an elastic roller D-1 in which a silicone rubber elastic layer having a diameter of 12 mm was formed on the outer periphery of the base was produced.

(Preparation of surface layer)
The synthesis example for obtaining the polyurethane surface layer (34 in FIG. 3) of the present invention is shown below.

(Synthesis of isocyanate group-terminated prepolymer A-1)
Polypropylene glycol polyol (trade name: Exenol 4030; manufactured by Asahi Glass Co., Ltd.) 100 with respect to 17.7 parts of tolylene diisocyanate (TDI) (trade name: Cosmonate T80; manufactured by Mitsui Chemicals) in a reaction vessel under a nitrogen atmosphere 0.0 g was gradually added dropwise while maintaining the temperature in the reaction vessel at 65 ° C. After completion of the dropping, the reaction was carried out at a temperature of 65 ° C. for 2 hours. The obtained reaction mixture was cooled to room temperature to obtain an isocyanate group-terminated prepolymer A-1 having an isocyanate group content of 3.8% by mass.

(Synthesis of amino compound B-3)
In a reaction vessel equipped with a stirrer, a thermometer, a dropping device, and a temperature controller, 100.0 parts (0.97 mol) of diethylenetriamine and 100 parts of ethanol were heated to 40 ° C. while stirring. Next, 235.0 parts (5.34 mol) of ethylene oxide was gradually added dropwise over 30 minutes while maintaining the reaction temperature at 60 ° C. or lower. The reaction was further stirred for 1 hour to obtain a reaction mixture. The obtained reaction mixture was heated under reduced pressure to distill off ethanol to obtain 276 g of amino compound B-3.

<Preparation of Toner Carrier 1>
As a material for the surface layer, 33.2 parts of amino compound B-3, 117.4 parts of carbon black (trade name, MA230; manufactured by Mitsubishi Chemical Corporation), and 618.9 parts of isocyanate group-terminated prepolymer A-1; 130.4 parts of urethane resin fine particles (trade name, Art Pearl C-400; manufactured by Negami Kogyo Co., Ltd.) were mixed with stirring.

  Next, methyl ethyl ketone (hereinafter referred to as MEK) was added so that the total solid content ratio was 30%, and then mixed in a sand mill. Next, the surface layer-forming coating material was prepared by adjusting the viscosity to 10 to 13 cps with MEK.

  The elastic roller D-1 produced previously was immersed in the coating material for surface layer formation, the coating film of the said coating material was formed on the surface of the elastic layer of the elastic roller D-1, and it was made to dry. Further, a heat treatment was performed at a temperature of 150 ° C. for 1 hour to provide a surface layer having a film thickness of about 15 μm on the outer periphery of the elastic layer, whereby a toner carrier 1 was produced.

<Preparation of Toner Carrier 2>
(Preparation of substrate)
As a substrate, a primer (trade name, DY35-051; manufactured by Toray Dow Corning Co., Ltd.) was applied and baked on a ground aluminum cylindrical tube having an outer diameter of 10 mmφ (diameter) and an arithmetic average roughness Ra of 0.2 μm.

(Production of elastic roller)
The substrate prepared above was placed in a mold, and an addition type silicone rubber composition in which the following materials were mixed was injected into a cavity formed in the mold.
-100 parts of liquid silicone rubber material (trade name, SE6724A / B; manufactured by Toray Dow Corning)-15 parts of carbon black (trade name, Toka Black # 4300; manufactured by Tokai Carbon Co.)-Silica powder as a heat resistance imparting agent Body 0.2 part / Platinum catalyst 0.1 part Subsequently, the mold was heated to cure and cure the silicone rubber at a temperature of 150 ° C. for 15 minutes. The substrate on which the cured silicone rubber layer was formed on the peripheral surface was removed from the mold, and then the substrate was further heated at a temperature of 180 ° C. for 1 hour to complete the curing reaction of the silicone rubber layer. Thus, an elastic roller D-2 in which a silicone rubber elastic layer having a film thickness of 0.5 mm and a diameter of 11 mm was formed on the outer periphery of the substrate 1 was produced.

(Preparation of surface layer)
As a material for the surface layer, 33.2 parts of amino compound B-3, 117.4 parts of carbon black (trade name, MA230; manufactured by Mitsubishi Chemical Corporation), and 618.9 parts of isocyanate group-terminated prepolymer A-1; 130.4 parts of urethane resin fine particles (trade name, Art Pearl C-400; manufactured by Negami Kogyo Co., Ltd.) were mixed with stirring.

  Next, MEK was added so that the total solid content ratio was 30% by mass to prepare a coating material for forming a surface layer.

  Next, the rubber-free portion of the previously produced elastic roller D-2 was masked and stood vertically, and rotated at 1500 rpm, and the paint was applied while lowering the spray gun at 30 mm / s. Subsequently, the coating layer was cured and dried by heating at a temperature of 180 ° C. for 20 minutes in a hot air drying oven to provide a surface layer having a film thickness of about 8 μm on the outer periphery of the elastic layer, thereby producing a toner carrier 2.

<Production example of strontium titanate fine particles 1>
The hydrous titanium oxide obtained by hydrolyzing the titanyl sulfate aqueous solution was washed with pure water until the electric conductivity of the filtrate reached 2200 μS / cm. NaOH was added to the hydrous titanium oxide slurry, and the sulfate radical adsorbed was washed with SO ₃ until it became 0.24%. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH of the slurry to 1.0 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was 6.0, and the supernatant was washed by decantation with pure water until the electrical conductivity of the supernatant reached 120 μS / cm.

533 g (0.6 mol) of metatitanic acid having a moisture content of 91% obtained as described above was put into a SUS reaction vessel, and nitrogen gas was blown into the vessel and left for 20 minutes to replace the inside of the reaction vessel with nitrogen gas. 183.6 g (0.66 mol) of Sr (OH) ₂ .8H ₂ O (purity 95.5%) was added, and distilled water was further added to add 0.3 mol / liter (SrTiO ₃ equivalent), SrO / TiO _2. A slurry with a molar ratio of 1.10 was prepared.

  The slurry was heated to 90 ° C. in a nitrogen atmosphere to carry out the reaction. After the reaction, the reaction solution is cooled to 40 ° C., the supernatant is removed under a nitrogen atmosphere, and the operation of adding 2.5 liters of pure water and decanting is repeated twice, followed by filtration with Nutsche. It was. The obtained cake was dried in the atmosphere at 110 ° C. for 4 hours to obtain strontium titanate fine particles.

  100 parts of strontium titanate fine particles were added to a sodium stearate aqueous solution (7 parts of sodium stearate and 100 parts of water) which is a fatty acid metal salt. While stirring, an aqueous aluminum sulfate solution was dropped, and aluminum stearate was deposited and adsorbed on the surface of strontium titanate fine particles to prepare strontium titanate treated with stearic acid.

<Production example of strontium titanate fine particles 2 to 7>
The strontium titanate fine particles 2 to 7 shown in Table 4 were produced in accordance with the production example of the strontium titanate fine particles 1 except that the reaction time after the slurry was heated to 90 ° C. was adjusted to the target particle size. did.

<Inorganic fine particles>
Table 5 shows a list of inorganic external additives other than the strontium titanate fine particles 1 to 7 used in the present invention.

<Production Example of Large Particle Size Silica Particles 1 and 2>
In a 3 L glass reactor equipped with a stirrer, a dropping funnel and a thermometer, 621.3 g of methanol, 42.0 g of water, and 47.1 g of 28 mass% ammonia water were added and mixed. The obtained solution was adjusted to 35 ° C., and 1100.0 g (7.23 mol) of tetramethoxysilane and 395.2 g of 5.4 mass% aqueous ammonia were simultaneously added while stirring. Tetramethoxysilane was added dropwise over 6 hours and ammonia water was added over 5 hours. After completion of the dropwise addition, the mixture was further stirred for 0.2 hours for hydrolysis to obtain a methanol-water dispersion of hydrophilic spherical sol-gel silica fine particles. Next, an ester adapter and a condenser tube were attached to a glass reactor, and the dispersion was sufficiently dried at 80 ° C. under reduced pressure. The obtained silica particles were heated at 400 ° C. for 10 minutes in a thermostatic bath.

  The above process was carried out a plurality of times, and the resulting silica particles were crushed with a pulverizer (manufactured by Hosokawa Micron).

  Thereafter, as a surface treatment step, first, 500 g of silica particles were charged into a polytetrafluoroethylene inner cylindrical stainless steel autoclave having an internal volume of 1000 mL. Next, the inside of the autoclave was replaced with nitrogen gas. Then, while rotating the stirring blade attached to the autoclave at 400 rpm, 2.0 g of HMDS (hexamethyldisilazane (surface treatment agent)) and 1.0 g of water are atomized with a two-fluid nozzle into silica particles. Sprayed evenly. After stirring for 30 minutes, the autoclave was sealed and heated at 200 ° C. for 2 hours. Subsequently, deammonia treatment was performed by reducing the pressure in the system while heating to obtain large-diameter silica particles 1. Table 6 shows the physical properties of the large-diameter silica particles 1.

  In the production example of the large particle size silica particles 1, the amounts of HMDS and water were changed from 2.0 g and 1.0 g to 10.0 g and 2.0 g to obtain large particle size silica particles 2. Table 6 shows the physical properties of the large-diameter silica particles 2.

<Production Example of Small Particle Size Silica Particle 1>
Untreated dry silica (number average particle diameter of primary particles = 9 nm) was charged into an autoclave equipped with a stirrer, and heated to 200 ° C. in a fluidized state by stirring.

  The inside of the reactor was replaced with nitrogen gas, and the reactor was sealed, and 25 parts of hexamethyldisilazane was sprayed on the inside of 100 parts of the silica base, and the silane compound treatment was performed in a fluidized state of silica. This reaction was continued for 60 minutes, and then the reaction was terminated. After completion of the reaction, the autoclave was depressurized and washed with a nitrogen gas stream to remove excess hexamethyldisilazane and by-products from the hydrophobic silica.

Further, 20 parts of dimethyl silicone oil (viscosity = 100 mm ² / s) was sprayed on 100 parts of the silica base while stirring in the reaction vessel, and stirring was continued for 30 minutes. The mixture was further warmed and stirred for another 3 hours, and then taken out and crushed to obtain small-diameter silica particles. The small silica particle 1 had a particle size of 9 nm, a BET of 130 m ² / g, and an apparent density of 30 g / L.

<Example of production of polyester resin 1>
The following components were placed in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and reacted for 10 hours while distilling off the water produced at 230 ° C. under a nitrogen stream.
・ Bisphenol A EO 2 mol adduct 350 parts ・ Bisphenol A PO 2 mol adduct 326 parts ・ Terephthalic acid 250 parts ・ Titanium catalyst (titanium dihydroxybis (triethanolaminate)) 2 parts Then, under reduced pressure of 5 to 20 mmHg When the acid value becomes 0.1 or less, it is cooled to 180 ° C., 15 parts of trimellitic anhydride is added, taken out after reaction for 2 hours under normal pressure sealing, cooled to room temperature, pulverized and polyester Resin 1 was obtained. The acid value of the obtained resin was 1.0 mgKOH / g.

<Production example of magnetic body 1>
During an aqueous ferrous sulfate solution, 1.10 eq of sodium hydroxide solution from 1.00 relative to iron element, the amount of P ₂ O ₅ to an iron element to be 0.15% by mass in terms of phosphorus, the iron element On the other hand, SiO ₂ in an amount of 0.50% by mass in terms of silicon element was mixed to prepare an aqueous solution containing ferrous hydroxide. The pH of the aqueous solution was 8.0, and an oxidation reaction was performed at 85 ° C. while blowing air to prepare a slurry liquid having seed crystals.

  Subsequently, after adding ferrous sulfate aqueous solution so that it may become 0.90 to 1.20 equivalent with respect to the original alkali amount (sodium component of caustic soda) to this slurry liquid, the slurry liquid is maintained at pH 7.6, The oxidation reaction was promoted while blowing air to obtain a slurry liquid containing magnetic iron oxide. After filtration and washing, the water-containing slurry was once taken out. At this time, a small amount of water-containing sample was collected and the water content was measured. Next, this water-containing sample is put into another aqueous medium without being dried, stirred and redispersed with a pin mill while circulating the slurry, and the pH of the redispersed liquid is adjusted to about 4.8. Then, 1.6 parts of n-hexyltrimethoxysilane coupling agent was added to 100 parts of magnetic iron oxide with stirring (the amount of magnetic iron oxide was calculated as a value obtained by subtracting the water content from the water-containing sample), and water was added. Decomposition was performed. Thereafter, the mixture was sufficiently stirred, and the dispersion was subjected to surface treatment at a pH of 8.6. The produced hydrophobic magnetic material is filtered with a filter press, washed with a large amount of water, dried at 100 ° C. for 15 minutes, and then at 90 ° C. for 30 minutes. 0.21 μm magnetic body 1 was obtained.

<Production Example of Toner Particle 1>
(Preparation of aqueous medium)
After charging 3.12.8 parts of sodium phosphate 12 hydrate into 342.8 parts of ion-exchanged water and heating to 60 ° C. with stirring using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) Then, an aqueous calcium chloride solution in which 1.8 parts of calcium chloride dihydrate was added to 12.7 parts of ion-exchanged water was added and stirring was continued to obtain an aqueous medium containing a dispersion stabilizer.

(Preparation of polymerizable monomer composition)
-Styrene 75.0 parts-N-butyl acrylate 25.0 parts-1-6 hexanediol diacrylate 0.5 parts-Aluminum salicylate compound (E-101: manufactured by Orient Chemical Co., Ltd.) 0.5 parts-Colorant: Magnetic Body 1 65.0 parts / Polyester resin 1 10.0 parts The above materials were uniformly dispersed and mixed using an attritor (manufactured by Mitsui Miike Chemical Co., Ltd.), then heated to 60 ° C., and paraffin wax was added thereto. (Peak temperature of maximum endothermic peak: 80 ° C.) 15.0 parts were added, mixed and dissolved to obtain a polymerizable monomer composition.

(Granulation)
The polymerizable monomer composition and 7.0 parts of t-butyl peroxypivalate as a polymerization initiator are charged into the aqueous medium, and a TK homomixer (Special Machine Industries Co., Ltd.) at 60 ° C. under N ₂ atmosphere. Granulation with stirring at 12,000 rpm for 10 minutes to obtain a granulation liquid containing droplets of the polymerizable monomer composition.

(Polymerization / distillation / drying /)
The granulation liquid was reacted at 74 ° C. for 4 hours while stirring with a paddle stirring blade. After completion of the reaction, the mixture was distilled at 98 ° C. for 5 hours, and then the suspension was cooled, washed with hydrochloric acid, filtered, and dried to obtain toner particles 1 having a weight average particle diameter of 8.0 μm.

  The toner obtained had a particle size distribution (D50 / D1) of 1.12 and an average circularity of 0.979.

<Production Example of Toner 1>
Using a Henschel mixer FM10C (Mitsui Miike Chemical Co., Ltd.), using 100 parts of toner particles 1, 0.3 parts of strontium titanate fine particles 1 and 0.3 parts of large particle size silica particles 1 An additive mixing step was performed. The rotation speed and operation time of the Henschel mixer FM10C at that time were 4000 rpm and 5 minutes. The temperature of the Henschel mixer jacket was adjusted to 40 ° C.

  Next, the entire amount extracted from the apparatus and 0.6 part of the small particle size silica particles 10 were put into the apparatus shown in FIG.

  In order to mix the toner particles and the small-diameter silica particles 1 uniformly, the first mixing was performed. The first mixing condition was that the power of the drive unit 8 was 0.10 W / g (the rotational speed of the drive unit 8 was 150 rpm), and the processing time was 1 minute.

  Then, the 2nd mixing process was performed and the particle mixture was obtained. The power and operating time at that time were 0.3 W / g (1200 rpm) and 5 minutes, respectively.

1, the diameter of the inner peripheral part of the main casing 1 is 130 mm, and the volume of the processing space 9 is 2.0 × 10 ⁻³ m ³ . The rated power was 5.5 kW, and the shape of the stirring member 3 was that of FIG. The overlapping width d of the stirring member 3a and the stirring member 3b in FIG. 2 is 0.25D with respect to the maximum width D of the stirring member 3, and the clearance between the stirring member 3 and the inner periphery of the main body casing 1 is 3.0 mm. .

  After the external addition and mixing treatment, coarse particles and the like were removed with a circular vibration sieve equipped with a screen having a diameter of 500 mm and an opening of 75 μm, whereby Toner 1 was obtained.

<Production Examples of Toners 2 to 22>
Toners 2 to 22 were produced in the same manner as in Production Example of Toner 1 for Example, except that the type and number of added external additives and the external addition conditions shown in Table 7 were changed. Table 8 shows the physical properties of Toner 2 to 22 obtained.

<Example 1>
(Image forming device)
A Canon printer LBP7700C was remodeled and used for image evaluation. As a remodeling point, as shown in FIG. 4, the toner supply member of the developing device is rotated in the reverse direction to the toner carrier, and the voltage application to the toner supply member is turned off. Further, the cleaning blade was removed, and the contact pressure was adjusted so that the width of the contact portion between the toner carrier and the electrostatic latent image carrier was 1.1 mm.

  Further, the charging roller was changed to the charging roller 1 and modified so that the peripheral speed ratio of the charging roller 1 to the electrostatic latent image carrier was 120%.

  The developing device thus modified was charged with 100 g of toner 1, and a developing device was produced using the toner carrier 1. The produced developing device was set in a black station.

  Next, in a low-temperature and low-humidity environment (15 ° C., 10% RH), a DC voltage was applied to the charging member so that the potential on the electrostatic latent image carrier was −900V. Further, a DC voltage of −300 V was applied to the toner carrier, and an image printing test was performed so that | V1−V2 |

  The image is a horizontal line with a printing rate of 2%. After printing 2000 sheets by continuous paper feeding, 100 g of toner 1 is further supplied to the developing device, and 2000 sheets are printed by continuous paper feeding (total 4000). Image).

  As a result, it was possible to obtain an image having a good image density and no image defects even in a low temperature and low humidity environment even without a cleaner. Table 9 shows the evaluation results.

  The evaluation methods for each evaluation performed in the examples and comparative examples of the present invention and the judgment criteria thereof will be described below.

[Image density]
The image density formed a solid image portion, and the density of the solid image was measured with a Macbeth reflection densitometer (manufactured by Macbeth).
A: 1.40 or more B: 1.35 or more and 1.39 or less C: 1.30 or more and 1.34 or less D: 1.29 or less

[Image defect]
The image defect was confirmed by visual observation of the electrostatic latent image carrier and the solid black image.
A: No fused material is generated on the electrostatic latent image carrier.
B: A slight amount of fusion material is generated on the electrostatic latent image carrier, but no image defect occurs.
C: Slightly fused material is generated on the electrostatic latent image carrier, and 1 to 5 minute image defects are generated.
D: Fusion material is generated on the electrostatic latent image carrier, and 5 or more fine image defects are generated, or 1 to 5 coarse image defects are generated.

<Examples 2 to 22, 30>
A developing device was produced by combining the toner, the charging roller, and the peripheral speed ratio as shown in Table 9, and image output evaluation was performed in the same manner as in Example 1. As a result, it was possible to obtain an image having a good image density and no image defects in a low temperature and low humidity environment. Table 9 shows the evaluation results.

<Reference Examples 1 to 11>
A developing device was produced by combining the toner, the charging roller, and the peripheral speed ratio as shown in Table 9, and image output evaluation was performed in the same manner as in Example 1. As a result, it was possible to obtain an image density having no practical problem and an image defect level having no practical problem in a low temperature and low humidity environment. Table 9 shows the evaluation results.

<Comparative Example 1>
A developing device was produced by combining the toner, the charging roller, and the peripheral speed ratio as shown in Table 6, and the image formation evaluation was performed in the same manner as in Example 1. As a result, image defects occurred in a low temperature and low humidity environment. Table 9 shows the evaluation results.

<Example 23>
A Canon printer LBP3100 was modified and used for image evaluation. As a remodeling point, as shown in FIG. 4, the toner carrying member was remodeled so as to contact the electrostatic latent image carrying member. Further, the cleaning blade was removed, and the contact pressure was adjusted so that the width of the contact portion between the toner carrier and the electrostatic latent image carrier was 1.0 mm.

  Further, the charging roller was changed to the charging roller 1 and modified so that the peripheral speed ratio of the charging roller 1 to the electrostatic latent image carrier was 120%.

  The developing device thus modified was charged with 100 g of toner 1 and a toner carrying member 2 was used to produce a developing device.

  In a low temperature and low humidity environment (15 ° C., 10 RH), a DC voltage was applied to the charging member so that the potential on the electrostatic latent image carrier was −800V. Further, a DC voltage of −300 V was applied to the toner carrying member, and an image printing test was performed so that | V1−V2 |

  The image is a horizontal line with a printing rate of 2%. After printing 2000 sheets by continuous paper feeding, 100 g of toner 1 is further supplied to the developing device, and 2000 sheets are printed by continuous paper feeding (total 4000). Image).

  As a result, it was possible to obtain an image having a good image density and no image defects even in a low temperature and low humidity environment even without a cleaner. Table 10 shows the evaluation results.

<Examples 24-29>
A developing device was produced by combining the toner, the charging roller, and the peripheral speed ratio as shown in Table 10, and the image formation evaluation was performed in the same manner as in Example 23. As a result, it was possible to obtain an image density having no practical problem and an image defect level having no practical problem in a low temperature and low humidity environment. Table 9 shows the evaluation results.

  1: main body casing, 2: rotating body, 3, 3a, 3b: stirring member, 4: jacket, 5: raw material inlet, 6: product outlet, 7: central shaft, 8: drive unit, 9: processing space, 10: Rotating body end side surface, 11: Rotating direction, 12: Return direction, 13: Feeding direction, 16: Inner piece for raw material inlet, 17: Inner piece for product outlet, d: Overlapping portion of stirring member Interval, D: Width of stirring member, 31: Toner carrier, 32: Substrate, 33: Elastic layer, 34: Surface layer, 45: Electrostatic latent image carrier (photoconductor), 46: Charging roller, 47: Toner Carrier: 48: Toner supply member, 49: Developer, 50: Transfer member (transfer roller), 51: Fixing device, 52: Pickup roller, 53: Transfer material (paper), 54: Laser generator, 55: Toner Restriction member, 56: metal plate, 57: toner, 8: stirring member, 59: Magnetic

Claims (14)

Electrostatic latent image carrier,
A contact-type charging roller for charging the electrostatic latent image carrier;
Image exposure means for irradiating the surface of the electrostatic latent image carrier charged with image exposure light to form an electrostatic latent image on the surface of the electrostatic latent image carrier;
A developing device having a developing means for developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier to form a toner image on the surface of the electrostatic latent image carrier;
A transfer means for transferring the toner image formed on the surface of the latent electrostatic image bearing member to or from a transfer material with or without an intermediate transfer member; and
Fixing means for fixing the toner image transferred to the transfer material to the transfer material;
There is no cleaning means for removing unnecessary toner on the electrostatic latent image carrier on the downstream side of the transfer means and the upstream side of the contact-type charging roller, and transfer after the toner image is transferred. In an image forming apparatus that collects residual toner with the developing device,
The developing device is
Toner for developing the electrostatic latent image;
A toner carrier for carrying the toner, and a regulating member for regulating the layer thickness of the toner carried on the toner carrier;
The toner carrier is disposed in contact with the electrostatic latent image carrier;
The contact charging roller rotates in the forward direction with respect to the electrostatic latent image carrier, and the peripheral speed ratio is 105% or more and 140% or less,
The contact-type charging roller is
A mandrel having a surface layer on the outer periphery of the elastic layer and the elastic layer, the universal hardness of the surface layer is at 1.0 N / mm ² or more 17.0 N / mm ² or less,
The toner is
A toner having toner particles and inorganic fine particles containing a binder resin and a colorant;
The inorganic fine particles have a number average particle diameter (D1) of primary particles of 50 nm or more and 500 nm or less,
The toner is
The inorganic fine particles are contained in an amount of 0.1 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the toner particles, and the toner has a fixing ratio of the inorganic fine particles of 50% by mass or more and 90% by mass or less. An image forming apparatus. ^2. The image forming apparatus according to claim 1, wherein a universal hardness of a surface layer of the contact-type charging roller is 1.0 N / mm ² or more and 10.0 N / mm ² or less.   The surface layer of the contact-type charging roller includes a resin and conductive particles, and the surface of the surface layer has a convex portion due to the conductive particles. Image forming apparatus. The number of convex portions derived from the conductive particles in the surface layer is 50 or more and 500 or less in a 2.0 μm vertical and 2.0 μm horizontal region (4.0 μm ² region). The image forming apparatus described.   The image forming apparatus according to claim 1, wherein the inorganic fine particle is an oxide containing at least one metal selected from magnesium, aluminum, and titanium.   The image forming apparatus according to claim 1, wherein the inorganic fine particles have a cubic shape or a rectangular parallelepiped shape.   The image forming apparatus according to claim 1, wherein the inorganic fine particles are strontium titanate. In the four regions according to the following definitions in the reflected electron image of the toner surface imaged using a scanning electron microscope,
The average presence rate of the inorganic fine particles is 1.5 area% or more and 15.0 area% or less, and the variation coefficient of the number of the inorganic fine particles present in the four regions is 0.5 or less. The image forming apparatus according to any one of the above.
Coefficient of variation = standard deviation of the number of inorganic fine particles present / definition of the average number of inorganic fine particles present area: In the reflected electron image of the toner, the chord giving the maximum length is defined as a line segment A, which is parallel to the line segment A, Two straight lines separated from the line segment A by 1.5 μm are defined as a straight line B and a straight line C. A straight line passing through the midpoint of the line segment A and orthogonal to the line segment A is defined as a straight line D, parallel to the straight line D, and two straight lines separated from the straight line D by 1.5 μm are a straight line E and a straight line F. And Four regions that are squares with a side length of 1.5 μm formed by the line segment A and straight lines B, C, D, E, and F. An electrostatic latent image carrier;
A charging roller that rotates in the forward direction with a peripheral speed difference of 105% or more and 140% or less at a position of contact with the electrostatic latent image carrier, and charges the electrostatic latent image carrier;
A process cartridge that also serves as a cleaning device for the surface of the electrostatic latent image carrier, includes a developing device having toner, and is configured to be detachable from the image forming device,
Universal hardness of the surface layer of the charging roller is at 1.0 N / mm ² or more 17.0 N / mm ² or less,
The toner is
Toner particles containing a binder resin and a colorant;
Inorganic fine particles, wherein the inorganic fine particles have a primary particle number average particle diameter (D1) of 50 nm or more and 500 nm or less,
The inorganic fine particles are contained in an amount of 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the toner particles, and the fixing ratio of the inorganic fine particles is 50 to 90% by mass. Process cartridge characterized by. The process cartridge according to claim 9, wherein a universal hardness of a surface layer of the charging roller is 1.0 N / mm ² or more and 10.0 N / mm ² or less.   11. The process cartridge according to claim 9, wherein the surface layer of the charging roller includes a resin and conductive particles and has a convex portion due to the conductive particles. An electrostatic latent image carrier, a contact-type charging roller that charges the electrostatic latent image carrier, and the surface of the electrostatic latent image carrier that has been charged is irradiated with image exposure light. Image exposure means for forming an electrostatic latent image on the surface, and developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier to form a toner image on the surface of the electrostatic latent image carrier A developing process developed by a developing device having a developing means for carrying out;
A transfer step for transferring the toner image formed on the surface of the latent electrostatic image bearing member to a transfer material with or without an intermediate transfer member; and the toner image transferred to the transfer material. Having a fixing step for fixing to the transfer material;
There is no cleaning step for removing unnecessary toner on the electrostatic latent image carrier on the downstream side of the transfer material and the upstream side of the contact-type charging roller, and the transfer after transferring the toner image In the image forming method of collecting residual toner with the developing device,
The developing device is
Toner for developing the electrostatic latent image;
A toner carrier for carrying the toner, and a regulating member for regulating the layer thickness of the toner carried on the toner carrier;
The toner carrier is disposed in contact with the electrostatic latent image carrier, the contact charging roller rotates in the forward direction with respect to the electrostatic latent image carrier, and the peripheral speed ratio is 105% or more and 140%. And
The contact charging roller, a mandrel, having a surface layer on the outer periphery of the elastic layer and the elastic layer, the universal hardness of the surface layer be 1.0 N / mm ² or more 17.0 N / mm ² or less The toner is a toner having toner particles and inorganic fine particles containing a binder resin and a colorant,
The inorganic fine particles have a number average particle diameter (D1) of primary particles of 50 nm or more and 500 nm or less,
The toner has 0.1 to 1.0 part by mass of the inorganic fine particles with respect to 100 parts by mass of the toner particles, and the toner has a fixing ratio of the inorganic fine particles of 50 to 90% by mass. % Or less, and an image forming method. The image forming method according to claim 12, wherein a universal hardness of the surface layer of the contact-type charging roller is 1.0 N / mm ² or more and 10.0 N / mm ² or less.   The surface layer of the contact-type charging roller includes a resin and conductive particles, and the surface of the surface layer has a convex portion due to the conductive particles. Image forming method.

Images