JP6381424B2 - Image forming apparatus and image forming method - Google Patents

Description

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

  A number of methods are known as electrophotographic methods. In general, a photoconductive substance is used and an electrostatic latent image is formed on an electrostatic charge image carrier by various means. Next, the electrostatic latent image is developed with toner to form a visible image. If necessary, the toner image is transferred onto a recording medium such as paper, and then the toner image is fixed on the recording medium with heat or pressure. A copy is obtained. Examples of such an image forming apparatus include a copying machine and a laser beam printer (hereinafter referred to as LBP).

  These LBPs and copiers have recently made a transition from analog to digital, have excellent reproducibility of latent images and high resolution, and at the same time, LBP is strongly required to be downsized especially in the context of office space. .

  Further, even such a miniaturized LBP has a high image quality, and there is a great demand for high durability with little image quality fluctuation even in long-term use.

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

  Considering the development method, the LBP development method includes a two-component development method and a one-component development method. In the sense of compactness, the one-component development method is suitable. This is because a member such as a carrier is not used.

  Next, considering the downsizing in the one-component development, it is effective to reduce the diameter of the electrostatic latent image carrier or the toner carrier in order to downsize the developing device.

  As an image forming apparatus, 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 transfer residual toner) is scraped off by a cleaning blade or the like and collected in a cleaner container. However, since the cleanerless system does not have a cleaning blade and a cleaner container, the developing device can be greatly reduced in size.

  On the other hand, there are also problems specific to cleanerless systems. One of them is the recoverability of transfer residual toner. In the cleanerless system, the untransferred toner is collected on the toner carrier in a region where the toner carrier and the electrostatic latent image carrier abut (hereinafter referred to as a development region). However, when the transfer residual toner is poorly collected, the toner is carried on the electrostatic latent image carrier, and image deterioration such as an image defect due to irregular development on a non-image area and image adverse effects such as cleaner-less ghost are caused. It will occur.

  Here, the cleaner-less ghost is a phenomenon in which the transfer residual toner after the transfer is not collected by the developing unit and is transferred in the transfer process again.

  Focusing on the recoverability, the toner is more likely to be charged in a low-temperature and low-humidity environment, and the adhesion force of the toner to the electrostatic latent image carrier increases. As a result, the recoverability of the transfer residual toner tends to deteriorate.

  In response to such problems, for example, by superimposing a DC voltage on an alternating voltage on the developing bias, or controlling the circularity and residual magnetization of the toner, a cleanerless system can maintain good image quality in a normal temperature and humidity environment. There is also a report (refer to patent documents 1 and 2). However, even if these developing devices and toners are used, there is room for improvement in recoverability in a low temperature and low humidity environment.

  On the other hand, if the charge amount of the toner is decreased in order to reduce the adhesion between the toner and the electrostatic latent image carrier in order to improve the recoverability in a low temperature and low humidity environment, the fog is deteriorated particularly in a high temperature and high humidity environment. In general, the chargeability of fog toner is opposite to the normal charge polarity, or the amount of charge is almost zero, so that it is difficult to transfer. In the cleanerless system, since there is no mechanism for scraping off the transfer residual toner such as a cleaning blade, the transfer residual toner contaminates the charging member. When the charging member is contaminated, the set potential (potential on the electrostatic latent image carrier) cannot be obtained, and the fog tends to increase more easily.

  As described above, in the cleanerless system, it is difficult to achieve both recovery of the transfer residual toner in a low temperature and low humidity environment and fogging in a high temperature and high humidity environment, and there is room for further improvement.

JP 2005-173484 A JP 2006-154093 A

  The object of the present invention has been made in view of the above-described problems of the prior art, and improves the recoverability even when used for a long time in a low temperature and low humidity environment, and also provides a clear image without fogging in a high temperature and high humidity environment. An image forming apparatus that can be obtained is provided.

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,
Transfer means for transferring the toner image formed on the surface of the latent electrostatic image bearing member to the transfer material with or without an intermediate transfer member, and the toner image transferred to the transfer material A fixing unit for fixing to the transfer material; and a cleaning unit for removing unnecessary toner on the electrostatic latent image carrier on the downstream side of the transfer unit and the upstream side of the contact-type charging roller. In the image forming apparatus that is not provided and collects the transfer residual toner after the toner image is transferred 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 opposite to the electrostatic latent image carrier,
The contact-type charging roller has a shaft core, 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 10.0 N / mm ² or less. The volume resistivity of the surface layer is 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹⁶ Ωcm or less, the surface layer is made of a resin containing conductive particles, and the surface is made of minute protrusions by the conductive particles. Have
The toner is a toner having toner particles containing a binder resin and a colorant and silica fine particles,
The image forming apparatus is characterized in that the coefficient of static friction of the toner with respect to the polycarbonate resin substrate is 0.100 or more and 0.250 or less.

Further, the present invention provides an electrostatic latent image carrier, a contact-type charging roller that charges the electrostatic latent image carrier, and image exposure light applied to the surface of the charged electrostatic latent image carrier. An image exposure step 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 carrier A development process for forming a toner image on the surface of
A transfer step for transferring the toner image formed on the surface of the latent electrostatic image bearing member to the transfer material with or without an intermediate transfer member, and the toner image transferred to the transfer material. A fixing step for fixing to the transfer material, and a cleaning step for removing unnecessary toner on the electrostatic latent image carrier downstream of the transfer material and upstream of the contact-type charging roller. In the image forming method of recovering residual transfer toner after transferring the toner image 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 opposite to the electrostatic latent image carrier,
The contact-type charging roller has a shaft core, 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 10.0 N / mm ² or less. The volume resistivity of the surface layer is 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹⁶ Ωcm or less,
The surface layer is made of a resin containing conductive particles, and has fine convex portions by the conductive particles,
The toner is a toner having toner particles containing a binder resin and a colorant and silica fine particles, and the coefficient of static friction of the toner with respect to the polycarbonate resin substrate is 0.100 or more and 0.250 or less. Image forming method.

  By using an image forming apparatus having a specific configuration of the present invention, a clear image that is not fogged in a high temperature and high humidity environment is obtained, and the recovery property is improved even in a low temperature and low humidity environment. A good image can be obtained even in use.

It is a figure which shows the boundary line of a spreading | diffusion index. 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 cross-sectional view showing an example of a toner carrier according to the present invention. 1 is a schematic cross-sectional view illustrating an example of a developing device according to the present invention. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus having a developing device according to the present invention. 1 is a schematic cross-sectional view illustrating an example of a developing device according to the present invention.

  The image forming apparatus of the present invention is an apparatus in a cleaner-less system, and has the following configuration.

That is, the electrostatic latent image bearing member, a contact-type charging roller that charges the electrostatic latent image bearing member, and the surface of the charged electrostatic latent image bearing member is irradiated with image exposure light to carry the electrostatic latent image bearing member. Image exposing means for forming an electrostatic latent image on the surface of the body, developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier and developing toner on the surface of the electrostatic latent image carrier A developing device having developing means for forming an image,
Transfer means for transferring the toner image formed on the surface of the latent electrostatic image bearing member to the transfer material with or without an intermediate transfer member, and the toner image transferred to the transfer material A fixing unit for fixing to the transfer material; and a cleaning unit for removing unnecessary toner on the electrostatic latent image carrier on the downstream side of the transfer unit and the upstream side of the contact-type charging roller. In the image forming apparatus that is not provided and collects the transfer residual toner after the toner image is transferred 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. The toner carrier is disposed opposite the electrostatic latent image carrier, and the contact-type charging roller has a shaft core, an elastic layer, and a surface layer on an outer periphery of the elastic layer, The surface layer has a universal hardness of 1.0 N / mm ² or more and 10.0 N / mm ² or less, and the volume resistivity of the surface layer is 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹⁶ Ωcm or less, The surface layer is made of a resin containing conductive particles, and has a fine convex portion by the conductive particles,
The toner is a toner having toner particles containing a binder resin and a colorant and silica fine particles, and the coefficient of static friction of the toner with respect to the polycarbonate resin substrate is 0.100 or more and 0.250 or less. It is what.

  As a result of diligent investigations by the present inventors, the surface layer of the contact-type charging roller uses a specific material and shape, controls its physical properties, and reduces the static friction coefficient of the toner with respect to the polycarbonate resin substrate. Thus, the present invention has been achieved.

  The reason for this will be described below.

  First, collection of transfer residual toner in the cleanerless system will be described in detail. When developed from a toner carrier to an electrostatic latent image carrier, the toner formed on the surface of the electrostatic latent image carrier is generally negatively charged, but the transfer residual toner after the transfer step Then, a positive charging polarity opposite to that before transfer is obtained. Thereafter, by passing through the contact type charging roller, the transfer residual toner again obtains a negative charge polarity, and the transfer residual toner is collected on the toner carrier. When the transfer residual toner is poorly collected on the toner carrying member, the transfer residual toner is carried around on the surface of the electrostatic latent image carrying member, thereby causing image problems such as cleanerless ghost.

  In order to improve the recoverability of the transfer residual toner to the toner carrier, it is important to improve the efficiency of charge injection to the transfer residual toner and the adhesion of the toner to the transfer material when passing through the contact-type charging roller. The present inventors consider. Although the mechanism for solving the above problems is not clear, the present inventors consider as follows.

  In order to stabilize the charge injection to the transfer residual toner, it is important to keep the volume resistivity of the surface layer of the contact-type charging roller high. This is because by keeping the volume resistivity of the surface layer high, unnecessary discharge does not occur and the charge injection into the toner is stabilized.

  Furthermore, by softening the surface layer of the contact-type charging roller, the surface layer bends with respect to the toner, and many point contacts occur between the conductive particles that form minute protrusions on the surface layer and the transfer residual toner. Therefore, it is considered that the charge injection is performed efficiently. At this time, by keeping the hardness of the contact-type charging roller soft, deformation such as crushing or cracking of the toner can be suppressed. Accordingly, it is considered that there is an effect that the transfer residual toner is less crushed and cracked, and is easily injected into the charge and easily collected on the toner carrier. Further, in order to efficiently perform this point contact, it is important that the transfer residual toner is present as a large number of primary particles in a loose state, not as an aggregate on the electrostatic latent image carrier. They are thinking. In addition to the presence of residual transfer toner, by controlling the adhesion of the toner to a low level, the residual toner can be transferred to the electrostatic latent image carrier when it is recovered from the electrostatic latent image carrier. We think that it will be easier to get away from the body and the recovery will be improved.

In order to control the presence state of the transfer residual toner and the adhesion force of the toner in the cleanerless system, it is important to control the coefficient of static friction with respect to the polycarbonate resin substrate.
Conventionally, polycarbonate resin has been widely used as the outermost layer material of an electrostatic latent image carrier, and in the present invention, by controlling the coefficient of static friction with respect to the polycarbonate resin substrate, the effects of the present invention can be sufficiently exhibited. I found it.

The static friction coefficient is a proportional constant that determines the frictional force (maximum static frictional force) at the moment when the object starts moving from a state where it is stationary on the surface of the target member. When the coefficient of static friction is μ and the vertical effect on the member surface is N, the maximum static frictional force F0 is expressed by the following equation.
F0 = μN

  The maximum static friction force F0 increases as the static friction coefficient μ increases. As described above, the static friction coefficient μ of the toner of the present invention will be described below as an index of adhesion to members such as an electrostatic latent image carrier and ease of loosening of the transfer residual toner. Is thinking. By controlling this static friction coefficient μ, it is possible to control the presence state of the transfer residual toner on the electrostatic latent image carrier, and by lowering the toner adhesion force, the toner is carried from the electrostatic latent image carrier. The present inventors consider that it is easy to be collected into the body and the above problems can be solved.

  The present invention will be specifically described below.

<Charging roller>
The charging roller of 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 of the present invention is formed of a rubber component, and the rubber component is not particularly limited, and a known rubber 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>
As the surface layer, a resin known in the field of electrophotographic conductive members can be used. Specific examples include acrylic resin, polyurethane, polyamide, polyester, polyolefin, and silicone resin.

  For the resin forming the surface layer, the surface of the particles may be coated with conductive oxides such as carbon black, graphite, and tin oxide, metals such as copper and silver, oxides and metals, if necessary. An ion conductive agent having ion exchange performance such as conductive particles imparted with conductivity and quaternary ammonium salts may be used.

  A known binder resin can be used as the binder resin for forming the surface layer. Examples thereof include resins, natural rubber, vulcanized products thereof, and rubbers such as synthetic rubber. As the resin, fluorine resin, polyamide resin, acrylic resin, polyurethane resin, silicone resin, butyral resin, styrene-ethylene / butylene-olefin copolymer, olefin-ethylene / butylene-olefin copolymer, and the like can be used. In addition, as binder resin of this invention, it is preferable not to contain ether bonds, such as a polyethylene oxide and a polypropylene oxide. This is because ether urethane resins can reduce the universal hardness but are not suitable as the binder resin of the present invention because the volume resistivity of the resin is reduced. The said binder resin can be used individually or in combination of 2 or more types. Among these, in order to achieve both flexibility by reducing the universal hardness of the surface layer and high resistance of the surface layer, it is particularly preferable to include a polycarbonate structure. Since the polycarbonate structure has low polarity, the volume resistivity of the binder resin itself can be maintained high. Specifically, polycarbonate polyurethane obtained by copolymerizing polycarbonate polyol and polyisocyanate is preferable.

  Examples of the polycarbonate polyol include the following. Polynonamethylene carbonate diol, poly (2-methyl-octamethylene) carbonate diol, polyhexamethylene carbonate diol, polypentamethylene carbonate diol, poly (3-methylpentamethylene) carbonate diol, polytetramethylene carbonate diol, polytrimethylene Carbonate diol, poly (1,4-cyclohexanedimethylene carbonate) diol, poly (2-ethyl, 2-butyl-trimethylene) carbonate diol, and random / block copolymers thereof.

  The polyisocyanate is selected from generally used polyisocyanates, and examples thereof include the following. Toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, hydrogenated MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and the like. Of these, aromatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and polymeric diphenylmethane polyisocyanate are more preferably used.

In the charging roller according to the present invention, the universal hardness of the surface layer is 1.0 N / mm ² or more and 10.0 N / mm ² or less, and the volume resistivity of the surface layer is 1.0 × 10 ¹⁰ Ωcm or more. It is 0 × 10 ¹⁶ Ωcm or less, and the surface layer is made of a resin containing conductive particles, and has a minute convex portion by the conductive particles.

When the universal hardness of the surface layer is greater than 10.0 N / mm ² , the toner is easily affected by crushing and cracking, and the efficiency of charge injection to the transfer residual toner is deteriorated. Further, the surface layer of the contact-type charging roller is less likely to bend with respect to the toner in an area where the contact-type charging roller and the electrostatic latent image carrier are in contact (hereinafter referred to as a charging nip). As a result, the charge injection efficiency to the transfer residual toner is reduced.

  The universal hardness of the charging roller of the present invention can be controlled 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.

The universal hardness on the surface of the charging roller is measured 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.

When the volume resistivity of the surface layer is less than 1.0 × 10 ¹⁰ Ωcm, the discharge to the electrostatic latent image carrier by the contact-type charging roller is not stable, and charging failure is likely to occur. This is likely to cause image defects (transfer omission) such that the solid black image has a mottled density.

  For the measurement of the volume resistivity of the surface layer, a measurement value measured by the conductive mode using an atomic force microscope (AFM) can be adopted. The surface layer of the charging roller is cut into a sheet using a manipulator, and metal deposition is performed on one surface of the surface layer. A DC power source is connected to the surface on which metal deposition has been performed, a voltage is applied, the free end of the cantilever is brought into contact with the other surface of the surface layer, and a current image is obtained through the AFM body. The volume resistivity can be calculated from the average current value at the top 10 locations of the measured low current values, the average film thickness, and the contact area of the cantilever, by measuring the current values at 100 randomly selected surfaces.

  The number average particle diameter of the conductive particles present in the surface layer is preferably 10 nm or more and 100 nm or less. When the conductive particles are smaller than 100 nm, the efficiency of charging injection into the transfer residual toner is improved, and the recovery performance of the transfer residual toner is easily improved. If the conductive particles present in the surface layer are larger than 10 nm, the strength reinforcing effect of the conductive fine particles on the surface layer is increased, so that the hardness of the resin tends to increase.

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

Further, in the present invention, since the fine protrusions derived from the conductive fine particles are used to inject charges into the transfer residual toner, it is important to control the number of the fine protrusions. 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 (more preferably 100 or more), it is possible to secure the number of convex portions as a starting point for injecting electric charge to the transfer residual toner. Further, by making the number 500 or less, it is possible to suppress the injection of charges into the photoreceptor. The calculation of the number of the minute convex portions can be performed 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. it can.

  Next, a method for exposing the conductive fine particles on the surface of the surface layer of the present invention 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, as shown in FIG. 2, the surface skin layer 24 of the binder resin 21 is removed by performing ultraviolet treatment, polishing method, electrolytic polishing method, chemical polishing method, ion milling method, etc. It can be exposed on the surface of the layer. Reference numeral 23 in FIG. 2 denotes conductive fine particles exposed on the surface. 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 micro convex part. When a height image is acquired in a state in which a skin layer after dip coating is present, the minute convex portions are 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.

  The toner used in the present invention has a coefficient of static friction with respect to the polycarbonate resin substrate of 0.100 or more and 0.250 or less, preferably 0.100 or more and 0.200 or less, more preferably 0.100 or more and 0.150. It is as follows. When the static friction coefficient is 0.250 or less, the adhesion force of the transfer residual toner to the surface of the electrostatic latent image carrier is sufficiently low, and the transfer residual toner is easily collected on the toner carrier. Further, by controlling the static friction coefficient to 0.250 or less, the transfer residual toner on the electrostatic latent image carrier is not agglomerated but loosened and the toner tends to exist as primary particles. As a result, the present inventors consider that a large amount of point contact with the contact-type charging roller described above is likely to occur, and charging injection is efficiently performed, so that the transfer residual toner is easily collected. The reason why the presence state of the transfer residual toner on the electrostatic latent image carrier can be controlled by controlling the coefficient of static friction with respect to the polycarbonate resin substrate is considered as follows.

  In the transfer step, the surface of the latent electrostatic image bearing member is a curved surface, so that it is not completely parallel to the paper surface. Therefore, even in a process in which the toner lump on the electrostatic latent image carrier comes into contact with the paper surface having higher adhesion than the electrostatic latent image carrier and is peeled off and transferred from the electrostatic latent image carrier, the electrostatic latent image carrier A force in the horizontal direction with respect to the surface acts on the toner lump to a certain extent. At this time, since the static friction coefficient can be controlled to be small, not only the toner is easily transferred to the paper but also the toner is compressed and it becomes difficult to form an agglomerate. Are likely to exist as primary particles.

  On the other hand, the static friction coefficient is less than 0.100. In the first place, the powder is mainly composed of resin such as toner, and after satisfying the performance as a toner, it is less than 0.100. In practice, it is difficult to reduce the static friction coefficient.

  Furthermore, when the static friction coefficient exceeds 0.250, toner agglomerates are easily generated on the electrostatic latent image carrier in the transfer process, and the transfer residual toner tends to exist in an aggregated state. The injection charging is not easily performed efficiently. Further, it is difficult to transfer from the electrostatic latent image carrier to a transfer material such as paper. As a result, the recoverability of the transfer residual toner is deteriorated and the cleaner-less ghost is likely to be deteriorated.

  The static friction coefficient can be adjusted to the above range by comprehensively controlling the shape, surface property, type and amount of external additive particles, and the adhesion state of the toner.

  It is possible to achieve the above-mentioned range of the coefficient of static friction by adding a relatively large amount of metal oxide particles or the like that have been subjected to various treatments using fatty acids or silicone oils that are generally used as lubricants. . However, in this case, the charging characteristics of the toner are often adversely affected, the electrophotographic characteristics required for the toner other than the recoverability of the transfer residual toner cannot be satisfied, and it is very difficult to function as a developer. Further, during durable use, adverse effects such as member contamination due to free external additive particles are likely to occur.

  Therefore, it is preferable to adjust the static friction coefficient within the above range by controlling the adhesion state of the silica fine particles on the toner surface instead of using a large amount of special external additives. Specifically, the coverage of the toner surface with silica fine particles and the uniformity of the coating state are important. Details of the effect obtained when the coverage of silica particles on the toner surface and the uniformity of the coating state are satisfied, and the details of the mechanism of the effect are unclear, but the present inventors presume as follows doing.

  Factors that determine the coefficient of static friction include (1) meshing of minute surface shapes of toner and target member, (2) electrostatic attractive force and intermolecular force between toner and target member, and (3) toner surface or The influence of the viscosity of the surface treatment agent such as oil existing on the surface of the silica fine particles, (4) adsorption of water molecules in the atmosphere to the surface of the toner member, and the like are conceivable.

  Then, by coating the toner surface with silica fine particles at an appropriate ratio, (1) the unevenness of the toner particle surface can be compensated, and (2) the charge state of the toner surface after transfer is locally uneven. Expected to be effective, and (3) free silica fine particles can act as particles having a bearing effect.

  Further, by uniformly coating the toner surface with silica fine particles, (1) suppressing local exposure of the highly adherent toner particle surface, (2) suppressing adsorption of water molecules on the toner member surface, (3) ) The effects of suppressing the generation of agglomerates of silica fine particles and reducing the frictional resistance due to the three-dimensional meshing by the agglomerates are also conceivable.

  As a comprehensive result of these effects, it is considered that the coefficient of static friction can be adjusted within the above range.

  On the other hand, the present inventors consider that the surface state of the toner particles is also important in order to exert the effect of coating with the silica fine particles. In order to appropriately coat the toner surface without forming local aggregates of silica fine particles, it is considered that the adhesion force between the toner surface and the silica fine particles needs to be in an appropriate range. When the adhesion on the toner surface is too high, it becomes difficult to sufficiently disperse the silica fine particles on the toner surface, and the above-mentioned effects are limited. In a specific toner component, a release agent or the like that has a relatively low molecular weight and is easy to soften is exposed to the surface, which is not preferable as compared with a binder resin or the like.

  In the toner used in the present invention, the coverage X1 with silica fine particles on the surface of the toner determined by an X-ray photoelectron spectrometer (ESCA) is preferably 50.0 area% or more and 75.0 area% or less.

  The coverage X1 can be calculated from the ratio of the Si element detection intensity when the toner is measured to the Si element detection intensity when the silica fine particle is measured by ESCA. The coverage X1 indicates the proportion of the area of the toner particle surface that is actually covered with silica fine particles.

  When the coverage ratio X1 is 50.0 area% or more and 75.0 area% or less, sufficient fluidity is given to the toner, and at the same time, the toner surface is appropriately coated with silica fine particles to reduce adhesion between the toners. it can. As a result, the transfer residual toner existing on the electrostatic latent image carrier is less likely to agglomerate, the point contact described above is likely to occur, and injection charging is easily performed efficiently, and the transfer residual toner can be collected. Easy to improve.

In the toner used in the present invention, it is preferable that the diffusion index represented by the following formula 1 satisfies the following formula 2 when the theoretical coverage by the silica fine particles of the toner is X2.
(Formula 1) Diffusion index = X1 / X2
(Expression 2) Diffusion index ≧ −0.0042 × X1 + 0.62

The theoretical coverage X2 by the silica fine particles of the toner is calculated by the following formula 3 using the content of the silica fine particles in the toner, the particle size of the silica fine particles, and the like. This indicates the ratio of the area that can theoretically cover the toner particle surface.
(Expression 3) Theoretical coverage X2 (area%) = 31/2 / (2π) × (dt / da) × (ρt / ρa) × C × 100
da: Number average particle diameter of silica fine particles (D1)
dt: weight average particle diameter of toner (D4)
ρa: True specific gravity of silica fine particles ρt: True specific gravity of toner C: Mass of silica fine particles / Mass of toner (C is the content of silica fine particles in the toner described later)

  The physical meaning of the diffusion index represented by the above formula 1 is shown below.

  The diffusion index indicates the difference between the actual coverage ratio X1 and the theoretical coverage ratio X2. The degree of this divergence is considered to indicate the number of silica fine particles laminated in two and three layers in the vertical direction from the toner particle surface. Ideally, the diffusion index is 1, but this is a case where the coverage ratio X1 coincides with the theoretical coverage ratio X2, and there is no state where there are no two or more layers of silica fine particles. On the other hand, when the silica fine particles are present on the toner surface as aggregated secondary particles, a difference between the actually measured coverage and the theoretical coverage is generated, and the diffusion index is lowered. In other words, the diffusion index can be paraphrased as indicating the amount of silica fine particles present as secondary particles.

  In the present invention, the diffusion index is preferably in the range represented by Formula 2 above, and this range is considered to be greater than that of toners produced by conventional techniques. A large diffusion index indicates that the amount of silica fine particles on the surface of the toner particles present as secondary particles is small and the amount present as primary particles is large. As described above, the upper limit of the diffusion index is 1.

  When the diffusion index is within the above range, silica particles are uniformly distributed as primary particles on the toner surface, and the adhesion force between the toners is reduced without impairing the charging characteristics of the toner. Furthermore, since the silica fine particles that are present as secondary particles are reduced, it is difficult for the silica fine particles to transfer to the contact charging roller when the contact charging roller and the transfer residual toner come into contact with each other. It becomes easy to suppress contamination of the roller. In other words, the contamination of the contact-type charging roller can be easily suppressed by suppressing the secondary particles of silica fine particles as much as possible and coating the toner particles with a small amount. In this way, by controlling the diffusion index, it becomes easier to suppress contamination of the contact-type charging roller, so that charge injection into the transfer residual toner can be performed efficiently and the transfer residual toner can be recovered. It is preferable because it is easy to improve.

  The boundary line of the diffusion index in the present invention is a function with the coverage X1 as a variable in the range where the coverage X1 is 50.0 area% or more and 75.0 area% or less. The calculation of this function is obtained empirically from the phenomenon that the adhesion force between the toners decreases when the coverage X1 and the diffusion index are obtained by changing the toner particles, external addition conditions, and the like.

  FIG. 1 is a graph plotting the relationship between the coverage ratio X1 and the diffusion index by using three types of external mixing conditions to produce a toner having an arbitrarily changed coverage ratio X1 by changing the amount of silica fine particles to be added. is there. Of the toners plotted in this graph, it was found that the toner plotted in the region satisfying Equation 2 improves the recovery of the transfer residual toner.

  Here, although details are not known about the reason why the diffusion index depends on the coverage X1, the present inventors presume as follows. In order to improve the transferability of the transfer residual toner, it is better that the amount of silica fine particles present as secondary particles is small, but the influence of the coverage X1 is also small. As the coverage X1 increases, the adhesion force of the toner gradually decreases, so that the allowable amount of silica fine particles existing as secondary particles increases. Thus, the boundary line of the diffusion index is considered to be a function with the coverage X1 as a variable. That is, there is a correlation between the coverage X1 and the diffusion index, and it is preferable to control the diffusion index according to the coverage X1.

When the diffusion index is in the range of the formula 4 shown below, the amount of silica fine particles present as secondary particles increases, the adhesion between the toners increases, the agglomerates increase, and contamination of the contact-type charging roller also occurs. Is also not preferable because it is difficult to suppress.
(Formula 4) Diffusion index <−0.0042 × X1 + 0.62

  In order to adjust the static friction coefficient with respect to the polycarbonate resin substrate described above, it is possible to adjust the external addition device, the order of external addition, the external addition strength, the external addition time, etc. It can be controlled by using an external additive (for example, a large particle size silica particle) in combination. As the silica fine particles used in the present invention, known ones can be used. However, in order to control the presence state of the transfer residual toner, a combination of the small particle size silica particles and the large particle size silica particles is used in combination with the transfer residual toner. This is particularly preferable because the cohesiveness is controlled and the adhesive force on the electrostatic latent image carrier is easily controlled.

  In addition, when the small-diameter silica particles and the large-diameter silica particles are used in combination, the apparatus for external addition and the order of external addition are also important. An example is shown below.

  First, it is preferable to externally add small-sized silica particles using the apparatus shown in FIG. 2 after externally adding large-sized silica particles using an external additive mixing apparatus having high diffusion and pulverization ability. 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, the coefficient of static friction with respect to the polycarbonate resin substrate can be easily adjusted.

  This is because the large particle size silica particles are less likely to be loosened due to the influence of the shape and particle size compared to the small particle size silica particles. Therefore, by externally adding toner particles and large-diameter silica particles first, shearing is easily applied to the large-diameter silica particles, and the large-diameter silica particles are easily loosened. On the other hand, when externally adding large particle size silica particles after externally adding small particle size silica particles to the toner particles, the fluidity increases because the small particle size silica particles are externally added to the toner particles. Cheap. As a result, the present inventors speculate that this is because it is difficult to apply a share to the large particle size silica particles, and it is difficult to loosen 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 adjusting the coefficient of static friction with respect to the polycarbonate resin substrate. 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 full width at half maximum is 25 nm or less, such coalesced particles are few, uniform adhesion of large-diameter silica particles on the surface of the toner particles is increased, and higher fluidity can be obtained. It becomes easy to adjust the coefficient of static friction with respect to the polycarbonate resin substrate.

  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 particles.

  The silica particles thus obtained are usually hydrophilic and have many surface silanol groups. Therefore, when used as an external additive for toner, the surface of silica particles is preferably subjected to a hydrophobic treatment.

  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.

  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 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 particles so that the degree of hydrophobicity measured by a methanol titration test is in the range of 30 to 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 particles. A preferable method is a method in which silica particles produced by vapor phase oxidation of a silicon halogen compound are chemically treated 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, Examples thereof include 3-diphenyltetramethyldisiloxane and dimethylpolysiloxane having 2 to 12 siloxane units per molecule, and having one hydroxyl group in Si at the terminal unit. 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 10,000 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 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 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.

  More preferably, the silica particles treated with silicone oil are 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 1 to 40 parts by mass, preferably 3 to 35 parts by mass with respect to 100 parts by mass of the silica particles, and good hydrophobicity is easily obtained.

Small particle size silica 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, silica particles having a hydrophobicity of 25 m ² / g to 300 m ² / g are used.

  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 particle size silica particles preferably have an apparent density of 15 g / L or more and 50 g / L or less, more preferably 20 g / L or more and 40 g / L or less. C is not densely clogged and exists with a lot of air between fine particles, indicating that the apparent density 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 diameter of the silica raw material, the BET specific surface area of the silica fine particles C to be obtained 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 silica fine particles C can be loosened into relatively small secondary particles, and the apparent density can be reduced.

Next, the material configuration of toner particles that can be used in the present invention will be described in detail.
Examples of the binder resin for the toner that can be used in the present invention include vinyl resins, polyester resins, epoxy resins, and polyurethane resins. 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乃至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乃至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乃至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 is also preferably used.

  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.

  The vinyl-based resin that can be used in the present invention may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. The crosslinking agent used in this case is, for example, an aromatic divinyl compound. , Divinylbenzene, divinylnaphthalene; examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5- Examples include pentanediol acrylate, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, and those obtained by replacing acrylates of the above compounds with methacrylates; diacrylate compounds linked by an alkyl chain containing an ether bond For example, diethylene Recall diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and those obtained by replacing acrylates of the above compounds with methacrylate Examples of 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, polyoxy Examples include ethylene (4) -2,2-bis (4hydroxyphenyl) propane diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate; For example, trade name MANDA (Nippon Kayaku) is raised.

  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 in producing the vinyl copolymer that can be used in the present invention include 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-). 2,4-dimethylvaleronitrile), 2,2'-azobis (-2,4-dimethylvaleronitrile), 2,2'-azopis (-2 methylptyronitrile), dimethyl-2,2'-azobis Isoptylate, 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 Side, ketone peroxides such as cyclohexanone peroxide, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydro Peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, de force Noyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, diisopropylperoxydicarbonate, di-2-ethylhexylperoxy Carbonate, di-n-propylperoxydicarbonate, di-2-engineered peroxyethyl carbonate, dimethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl per Oxide, t-butyl peroxyacetate, t-butyl peroxyisoptylate, t-butyl peroxyneodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxylaurate, t- Butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyisophthalate, t-butyl peroxyallyl carbonate, t-amyl peroxy 2-ethylhexanoate, di-t-butyl perper Carboxymethyl hexahydro 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 both low-temperature fixability and storage stability are easily achieved.

  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. As the colorant preferably used in the present invention, known ones can be used, and the following can be mentioned.

  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, a charge control agent may be added and used. 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; 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 less than 70 ° C., 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 exceeds 140 ° C., 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 from 5 to 20 mg, preferably 10 mg. This is put into 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 and normal temperature and humidity in 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 used in the present invention preferably has a weight average particle diameter (D4) of 5.0 μm to 10.0 μm, more preferably 6.0 μm to 9.0 μm from the viewpoint of developability and fixability. is there.

  In the present invention, the average circularity of the toner particles is preferably 0.960 or more, more preferably 0.970 or more, and further preferably 0.975 or more. When the average circularity of the toner particles is 0.960 or more, the toner has a spherical shape or a shape close thereto, and uniform coating with silica fine particles is easily obtained, and the adhesion force of the toner is also likely to be reduced. As a result, the transfer residual toner on the electrostatic latent image bearing member is also preferable because it is easy to make point injection with the conductive particles of the charging roller, and charge injection is easily performed.

  The toner of the present invention is not particularly limited in other production steps as long as it is a production method having a step of adjusting a static friction coefficient, and can be produced by a known method.

  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 suspension-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 as described above.

  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.

  In the suspension polymerization method, the toner particles contain the colorant as described above.

  In the present invention, when the magnetic toner is produced by the suspension polymerization method, the surface of the magnetic material is preferably subjected 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 the coupling agent is added to the dispersion, and the surface treatment is performed while the coupling agent is hydrolyzed. At this time, the agglomeration is sufficiently carried out using a device such as a pin mill or a line mill while stirring. It is more preferable to perform the surface treatment while dispersing.

  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.

  In addition, in the case of suspension polymerization, as described above, a charge control agent or a release agent may be contained.

  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 silica particles that are inorganic fine particles to the toner particles 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.

  As a mixing treatment apparatus for externally mixing the silica particles, a known mixing treatment apparatus can be used.

  However, as described above, when the small particle size silica particle and the large particle size silica particle are used in combination, it is preferable to externally mix by the following method.

  First, it is preferable to externally add small-sized silica particles using the apparatus shown in FIG. 2 after externally adding large-sized silica particles using an external additive mixing apparatus having high diffusion and pulverization ability. 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, the coefficient of static friction with respect to the polycarbonate resin substrate can be easily adjusted.

  FIG. 2 is a schematic view showing an example of a mixing treatment apparatus that can be used when externally mixing the small particle size 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 will be described later, the coverage X1 and the diffusion index are such that the toner particles and the small-diameter silica particles are likely to circulate in the direction of the rotation axis 47 of the rotator and are easily mixed sufficiently before the fixation proceeds. Is easily controlled within a preferable range in the present invention.

  On the other hand, FIG. 3 is a schematic diagram showing an example of the configuration of the 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.2 and FIG.3.

  The mixing treatment apparatus for externally mixing the small-diameter silica particles includes a rotating body 42 having at least a plurality of stirring members 43 installed on a surface thereof, a driving unit 48 that rotationally drives the rotating body, and a gap between the stirring member 43 and the stirring member 43. And a main body casing 41 provided.

  The clearance (clearance) between the inner peripheral portion 44 of the main body casing 41 and the stirring member 43 gives a uniform share to the toner particles, and loosens the small-sized silica particles from the secondary particles to the primary particles, while In order to easily adhere to the surface, it is important to keep it constant and minute.

  Further, in this apparatus, the diameter of the inner peripheral portion 44 of the main body casing 41 is not more than twice the diameter of the outer peripheral portion of the rotating body 42. 2 shows an example in which the diameter of the inner peripheral portion 44 of the main body casing 41 is 1.7 times the diameter of the outer peripheral portion of the rotating body 42 (the diameter of the body portion obtained by removing the stirring member 43 from the rotating body 42). . When the diameter of the inner peripheral portion of the main body casing 41 is not more than twice the diameter of the outer peripheral portion of the rotating body 42, 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 body casing 41 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 41 is about 130 mm, the clearance is about 2 mm or more and about 5 mm or less, and when the inner peripheral part diameter of the main body casing 41 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, the rotating body 42 is rotated by the driving unit 48, and the toner particles and the small particle size silica particles charged in the mixing unit are stirred. By mixing, the surface of the toner particles is externally added and mixed with small-diameter silica particles.

  As shown in FIG. 3, at least a part of the plurality of stirring members 43 causes the toner particles and the small-diameter silica particles to move in one axial direction of the rotating body as the rotating body 42 rotates in the direction of the arrow 51. It is formed as a feed stirring member 43a that is fed in the direction of arrow 53. Further, at least a part of the plurality of stirring members 43 causes the toner particles and the small-diameter silica particles to move in the other direction (indicated by the arrow 52) in the axial direction of the rotating body as the rotating body 42 rotates in the direction of the arrow 51. It is formed as a stirring member 43b for returning to the direction.

  Here, as shown in FIG. 2, when the raw material inlet 45 and the product outlet 46 are provided at both ends of the main body casing 41, the direction from the raw material inlet 45 to the product outlet 46 (in FIG. 2). (Right direction) is called “feed direction”.

  That is, as shown in FIG. 3, the plate surface of the feeding stirring member 43a is inclined so as to feed the toner particles in the feeding direction (the direction of the arrow 53). On the other hand, the plate surface of the stirring member 43b is inclined so as to send the toner particles and the small particle size silica particles in the return direction (the direction of the arrow 52). As a result, the external addition of the small-diameter silica particles to the surface of the toner particles is performed while repeating the feeding in the “feeding direction (the direction of the arrow 53)” and the feeding in the “returning direction” (the direction of the arrow 52). Mixing is performed.

  The stirring members 43a and 43b are a set of a plurality of members arranged at intervals in the circumferential direction of the rotating body 42. In the example shown in FIG. 3, the stirring members 43a and 43b form a pair of two members on the rotating body 42 at intervals of 180 degrees, but three at intervals of 120 degrees or at intervals of 90 degrees. It is good also as a set of many members, such as four sheets. In the example shown in FIG. 3, a total of 12 stirring members 43a and 43b are formed at equal intervals.

  Further, in FIG. 3, 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 has a width of about 20% to 30% with respect to the length of the rotating body 42 in FIG. . In FIG. 3, an example of 23% is shown.

  Furthermore, it is preferable that the stirring members 43a and 43b have some overlap d between the stirring member 43b and the stirring member when an extension line is drawn in the vertical direction from the end position of the stirring member 43a. Thereby, it is possible to efficiently share the small particle size silica 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. 3, if the toner particles can be fed 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 42 with a rod-shaped 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. 2 includes a rotating body 42 having at least a plurality of stirring members 43 installed on the surface thereof, a drive unit 48 that rotationally drives the rotating body 42, and a main casing provided with a gap between the stirring member 43 and the main body casing. 41 and a jacket 4 on the inner side of the main body casing 41 and on the side surface 410 of the rotating body, through which a cooling medium can flow.

  Further, in the apparatus shown in FIG. 3, the raw material inlet 45 formed on the upper portion of the main casing 41 and the externally mixed toner are removed from the main casing 41 in order to introduce the toner particles and the small silica particles. The product discharge port 46 formed in the lower part of the main body casing 41 is provided.

  Further, in the apparatus shown in FIG. 2, a raw material inlet inner piece 416 is inserted into the raw material inlet 45, and a product outlet inner piece 417 is inserted into the product outlet 6.

  In the present invention, first, the raw material inlet inner piece 416 is taken out from the raw material inlet 45, and the toner particles are put into the processing space 49 from the raw material inlet 45. Next, silica fine particles are introduced into the treatment space 49 from the raw material inlet 45, and an inner piece 416 for raw material inlet is inserted. Next, the rotating body 42 is rotated by the drive unit 48 (arrow 51 indicates the direction of rotation), and the processed material introduced above is stirred and mixed by a plurality of stirring members 43 provided on the surface of the rotating body 42. Externally added and mixed.

  The order of loading may be such that the silica fine particles are first charged from the raw material inlet 45 and then the toner particles are charged from the raw material inlet 45. 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 fed from the raw material inlet 45 of the apparatus shown in FIG.

  More specifically, controlling the power of the drive unit 48 to 0.2 W / g or more and 2.0 W / g or less as the external addition mixing processing condition, the covering ratio X1 and the diffusion index defined in the present invention are It is preferable in obtaining. Moreover, it is more preferable to control the power of the drive unit 48 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 X1 is difficult to increase and the diffusion index tends to be too low. On the other hand, when it is higher than 2.0 W / g, the diffusion index increases, but the silica fine particles tend to be embedded too much.

  Although it does not specifically limit as processing time, Preferably it is 3 minutes or more and 10 minutes or less. When the treatment time is shorter than 3 minutes, the coverage X1 and the diffusion index tend to be low.

The number of rotations of the stirring member at the time of external mixing is not particularly limited, but the shape of the stirring member 43 in the apparatus in which the volume of the processing space 49 of the apparatus shown in FIG. 2 is 2.0 × 10 ⁻³ m ³ is shown in FIG. The rotation speed of the stirring member when it is made is preferably 800 rpm or more and 3000 rpm or less. By being 800 rpm or more and 3000 rpm or less, it becomes easy to obtain the coverage X1 and the diffusion index defined in the present invention.

  Further, in the present invention, a particularly preferable processing method is to have a pre-mixing step before the external addition mixing processing operation. By including a 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 X1 is likely to be increased and the diffusion index is further increased.

  More specifically, as pre-mixing treatment conditions, the power of the drive unit 48 may be 0.06 W / g or more and 0.20 W / g or less, and the treatment time may be 0.5 minutes or more and 1.5 minutes or less. preferable. As premixing treatment conditions, when the load power is lower than 0.06 W / g or the treatment time is shorter than 0.5 minutes, sufficient uniform mixing as premixing is difficult. On the other hand, when the premixing treatment condition is such that the load power is higher than 0.20 W / g or the treatment time is longer than 1.5 minutes, the surface of the toner particles has a small particle size before sufficiently uniform mixing. Silica particles may be fixed.

Regarding the rotation speed of the stirring member in the pre-mixing process, when the volume of the processing space 49 of the apparatus shown in FIG. 2 is 2.0 × 10 ⁻³ m ³ and the shape of the stirring member 43 is that of FIG. The rotation speed of the stirring member is preferably 50 rpm or more and 500 rpm or less. By being 50 rpm or more and 500 rpm or less, it becomes easy to obtain the coverage X1 and the diffusion index defined in the present invention.

  After completion of the external mixing process, the product discharge port inner piece 417 is taken out from the product discharge port 46, and the rotating body 42 is rotated by the drive unit 48 to discharge the toner from the product discharge port 46. 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.

  FIG. 4 shows an embodiment of a toner carrier according to the image forming apparatus or process cartridge of the present invention. The conductive roller 1 (toner carrier) shown in FIG. 4 has an elastic layer 3 formed on the outer peripheral surface of a columnar or hollow cylindrical conductive substrate 2. The surface layer 4 covers the outer peripheral surface of the elastic layer 3.

<Substrate>
The substrate 2 functions as an electrode and a support member of the conductive roller 1, and is a metal or alloy such as aluminum, copper alloy, 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 3 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 3 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 3, 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 4 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. Next, the urethane resin according to the present invention can be obtained by reacting the isocyanate group-terminated prepolymer with a compound having a structure represented by the following 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 4 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 parts with respect to 100 mass parts of resin components which form a surface layer.

  When surface roughness is required for the toner carrier, fine particles for controlling roughness may be added to the surface layer 4. The fine particles for roughness control preferably have a volume average particle size of 3 to 20 μm. The amount of particles added to the surface layer is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resin solid content of the 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 4, Spraying with a coating material, immersion, or roll coating 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 developing device of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

  FIG. 5 is a schematic cross-sectional view showing an example of the developing device of the present invention. FIG. 6 is a schematic sectional view showing an example of an image forming apparatus in which the developing device of the present invention is incorporated.

  5 or 6, the electrostatic latent image carrier 5 that is an image carrier on which the electrostatic latent image is formed is rotated in the direction of the arrow R1. The toner carrier 7 rotates in the direction of the arrow R2 to convey the toner 17 to the developing area where the toner carrier 7 and the electrostatic latent image carrier 5 are opposed to each other. A toner supply member 8 is in contact with the toner carrier, and the toner 17 is supplied to the surface of the toner carrier by rotating in the direction of arrow R3.

  Around the electrostatic latent image carrier 5, a charging roller 6, a transfer member (transfer roller) 10, a fixing device 11, a pickup roller 12, and the like are provided. The electrostatic latent image carrier 5 is charged by the charging roller 6. Then, exposure is performed by irradiating the electrostatic latent image carrier 5 with laser light by the laser generator 14, and an electrostatic latent image corresponding to a target image is formed. The electrostatic latent image on the electrostatic latent image carrier 5 is developed with toner stored in a toner container in the developing device 9 to obtain a toner image. The toner image is transferred onto a transfer material (paper) 13 by a transfer member (transfer roller) 10 in contact with the electrostatic latent image carrier 5 via the transfer material. The transfer material (paper) 13 on which the toner image is placed is conveyed to the fixing device 11 and fixed on the transfer material (paper) 13.

  In the charging step of the developing device of the present invention, the electrostatic latent image carrier and the charging roller are in contact with each other by forming a contact portion, and a predetermined charging bias is applied to the charging roller so that the surface of the electrostatic latent image carrier is predetermined. It is preferable to use a contact charging device that charges to the 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 developing device 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 19 in FIG. 7). In this case, the toner carrier preferably has a fixed magnet having multiple poles inside, and preferably has 3 to 10 magnetic poles.

  In the present invention, the potential (V1) of the surface of the electrostatic latent image carrier when the charging means charges the surface of the electrostatic latent image carrier, and the potential applied to the toner carrier when developing the electrostatic latent image. The difference (| V1−V2 |) from the DC voltage (V2) is preferably 200 V or more and 600 V or less.

  | V1-V2 | and the recoverability are correlated, and the larger | V1-V2 |, the better the recoverability of the remaining toner. Therefore, | V1-V2 | is preferably 200 V or more. On the other hand, when | V1-V2 | is larger than 600V, fogging tends to deteriorate particularly in a high-temperature and high-humidity environment. Therefore, in the present invention, | V1-V2 | is preferably 200V or more and 600V or less.

  In the present invention, the value [V] of | V1−V2 | is higher than the value [V] in the high temperature and high humidity environment (32.5 ° C., 80 RH) [V] in the low temperature and low humidity environment (15 ° C., 10 RH). ] Is preferably higher than 100V. As described above, the recoverability of the residual toner in the low temperature and low humidity environment becomes better as | V1-V2 | is larger. On the other hand, if | V1-V2 | is large in a high-temperature and high-humidity environment, fog tends to deteriorate. For this reason, recoverability and fog are improved by increasing the value [V] of │V1-V2│ in a low-temperature and low-humidity environment by 100 V or more than the value [V] of │V1-V2│ in a high-temperature and high-humidity environment. It is compatible with each other and is very preferable.

  Next, it describes regarding the measuring method of each physical property which concerns on this invention.

<Quantitative method of silica particles>
(1) Determination of silica particle content in toner (standard addition method)
3 g of toner is put in an aluminum ring having a diameter of 30 mm, and pellets are produced at a pressure of 10 tons. Then, the intensity of silicon (Si) is obtained by wavelength dispersive X-ray fluorescence analysis (XRF) (Si intensity-1). The measurement conditions may be those optimized by the XRF apparatus to be used, but all the series of intensity measurements are performed under the same conditions. Silica particles having a primary particle number average particle size of 12 nm are added to the toner in an amount of 1.0 mass% with respect to the toner, and the mixture is mixed by a coffee mill.

  After mixing, after pelletizing in the same manner as described above, the strength of Si is obtained in the same manner as described above (Si strength -2). The same operation is performed to obtain Si strength (Si strength-3, Si strength-4) in a sample in which silica fine particles are added and mixed at 2.0 mass% and 3.0 mass% with respect to the toner. The silica content (mass%) in the toner is calculated by the standard addition method using Si strengths −1 to 4.

(2) Separation of silica particles from toner When the toner contains a magnetic substance, the silica fine particles are quantified through the following steps.

  5 g of toner is weighed into a 200 ml polycup with a lid using a precision balance, 100 ml of methanol is added, and the mixture is dispersed for 5 minutes with an ultrasonic disperser. Attract the toner with a neodymium magnet and discard the supernatant. Repeat the operation of dispersing with methanol and discarding the supernatant three times. After that, 10% NaOH 100ml, "Contaminone N" (Nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for cleaning precision measuring instrument pH7, organic builder, Wako Pure Chemicals) Add a few drops of Kogyo Kogyo), mix gently, and let stand for 24 hours. Then, it isolate | separates again using a neodymium magnet. At this time, rinse with distilled water repeatedly so that NaOH does not remain. The collected particles are sufficiently dried by a vacuum dryer to obtain particles A. By the above operation, the externally added silica particles are dissolved and removed.

(3) Measurement of Si intensity in particle A 3 g of particle A is put in an aluminum ring having a diameter of 30 mm, a pellet is prepared at a pressure of 10 tons, and the intensity of Si is obtained by wavelength dispersive X-ray fluorescence analysis (XRF). (Si strength -5). The silica content (mass%) in the particles A is calculated using Si strength -5 and Si strength -1 to 4 used in the determination of the silica content in the toner.

The amount of silica particles added externally is calculated by substituting each quantitative value into the following equation.
Externally added silica particle amount (mass%) = silica content in toner (mass%) − silica content in particle A (mass%)

<Measurement method of coverage X1>
The coverage X1 with silica particles on the toner surface is calculated as follows.

The following apparatus is used under the following conditions, and elemental analysis of the toner surface is performed.
-Measuring device: Quantum 2000 (trade name, manufactured by ULVAC-PHI Co., Ltd.)
・ X-ray source: Monochrome Al Kα
-Xray Setting: 100 μmφ (25 W (15 KV))
・ Photoelectron extraction angle: 45 degrees ・ Neutralization condition: Combined use of neutralizing gun and ion gun ・ Analysis area: 300 × 200 μm
・ Pass Energy: 58.70eV
・ Step size: 1.25eV
・ Analysis software: Maltipak (PHI)

  Here, the peak of C 1c (B.E.280 to 295 eV), O 1s (B.E. 525 to 540 eV) and Si 2p (B.E. 95 to 113 eV) is used for calculation of the quantitative value of Si atoms. It was used. The quantitative value of the Si element obtained here is Y1.

  Next, the silica fine particles are measured alone. As a method for obtaining the silica fine particles from the toner, the method described in “Separation of silica fine particles from toner” described above is used. Using the silica particles obtained here, the elemental analysis of the silica particles alone is performed in the same manner as the elemental analysis of the toner surface described above, and the quantitative value of the Si element obtained here is Y2.

In the present invention, the coverage X1 with silica particles on the toner surface is defined as follows.
Coverage ratio X1 (area%) = Y1 / Y2 × 100

  In order to improve the accuracy of this measurement, it is preferable to measure Y1 and Y2 twice or more.

<Method for Measuring Toner Weight Average Particle Size (D4)>
The weight average particle diameter (D4) of the toner is calculated as follows (also calculated in the case of toner particles). 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 an aperture tube of 100 μm 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. 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, the dedicated software is set 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 solution is placed 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 rpm. Then, 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 Dispersion System Tetora 150” (manufactured by Nikka Ki Bios) 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 (1) installed in the sample stand, the electrolytic solution (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . 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).

<Method for measuring number average particle diameter of primary particles of silica fine particles>
The number average particle diameter of the primary particles of the silica fine particles is calculated from the silica particle image on the surface of the toner photographed with 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 number average particle diameter of the primary particles of the silica 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 of the silica particles than the secondary electron image, the particle size of the silica particles 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 silica particles (above da) Drag within the magnification display section of the control panel to set the magnification to 100000 (100k). 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 on the toner surface is measured to determine the average particle size. Here, since some silica particles exist as agglomerates, the number average particle size of primary particles of silica fine particles (by calculating the maximum diameter of those that can be confirmed as primary particles and arithmetically averaging the obtained maximum diameter ( D1) Obtain (da).

<Method for measuring true specific gravity of toner and silica particles>
The true specific gravity of the toner and silica particles was measured by a dry automatic densimeter autopycnometer (manufactured by Yuasa Ionics). The conditions are as follows.
Cell: SM cell (10 ml)
Sample amount: about 2.0 g (toner), 0.05 g (silica fine particles)

  This measurement method measures the true specific gravity of a solid / liquid based on a gas phase substitution method. Similar to the liquid phase replacement method, it is based on Archimedes' principle, but uses a gas (argon gas) as a replacement medium, and therefore has high accuracy for micropores.

<Measuring method of average circularity of toner>
The average circularity of the toner 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 equivalent circle diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner 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.

<Measurement method of half width of peak in weight-based particle size distribution chart of large particle size silica particles>
The full width at half maximum of the peak in the weight-based particle size distribution chart 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 (adjust as appropriate depending on the sample)
-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 is prepared with an 8 wt% sucrose aqueous solution and a 24 wt% sucrose aqueous solution, 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.

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 with a syringe is injected into a disk centrifugal particle size distribution measuring apparatus DC24000, and the weight-based particle size distribution of silica particles A is measured.

  The details of the measurement method are as described above.

<Measuring method of static friction coefficient>
For the static friction coefficient of the toner with respect to the polycarbonate resin substrate, a granular material fluidity measuring device (Share Scan TS-12, manufactured by Sci-Tec) is used. Share scan is Prof. Virendra M.M. This is a device that performs the measurement based on the principle of the Morcoulomb model described in “CHARACTERIZING POWDER FLOWABILITY” (published 2002.1.224) written by Puri.

  Specifically, the following operations are performed.

The measurement is performed in a room temperature environment (23 ° C., 60% RH) using a linear shear cell (cylindrical shape, diameter 80 mm, capacity 140 cm ³ ) capable of linearly applying a shear force in the cross-sectional direction.

  A polycarbonate resin substrate shown below is placed on the bottom of the cell, toner is put into the cell, and a predetermined vertical load is applied. A compacted powder layer is produced so as to be in a close packed state under this vertical load.

  Then, a shear force is gradually applied to the compacted powder layer while continuously applying a vertical load, and the shear force at the time when the member (in this case, the polycarbonate resin substrate) to be measured for static friction on the bottom surface is measured. .

  This measurement is performed at 3.0 kPa, 6.0 kPa, 9.0 kPa, 12.0 kPa, 15.0 kPa, and 18.0 kPa, and the horizontal load is plotted on the vertical load, and the vertical axis indicates the shear force when the bottom surface moves. To perform linear approximation. The slope of the obtained approximate straight line becomes the static friction coefficient.

  The polycarbonate resin substrate used for the measurement is prepared by coating a polycarbonate resin on the substrate with a bar coat or the like and then drying it with a vacuum dryer. The weight average molecular weight (Mw) of the polycarbonate resin is 39000, and the molecular structure is represented by the following structural formula (4). The Rz value (JIS standard B0601: 10-point average roughness) was 0.53. The Rz value is in the same range as the Rz value obtained in a general manufacturing process of an electrostatic latent image carrier (photosensitive member) mainly composed of actual polycarbonate.

  In addition, “H” in the following structural formula indicates that the ring is not a benzene ring but a cyclohexane ring.

<Measurement of particle size of conductive particles>
A method for measuring the number of minute convex portions derived from the exposed portions of the conductive fine particles on the surface layer of the charging roller is as follows. First, an elastic layer including a surface layer is cut out from the charging roller, platinum is deposited on the outermost surface of the surface layer, and the length is 2.0 μm using a scanning electron microscope (trade name: S-4800, manufactured by Hitachi High-Technology Corporation). X A region having a width of 2.0 μm was observed at a magnification of 40000 times, and a photograph was taken. 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 fine convex portions 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 charging 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 position 1 μm deep from the surface of the surface layer of the charging roller was defined as “universal hardness (t = 1 μm position)”.

<Measurement of volume resistivity of surface layer>
The volume resistivity of the surface layer was measured by the conductive mode using an atomic force microscope (AFM) (Q-scope 250: Questant). First, the surface layer of the conductive roller was cut into a sheet having a width of 2 mm and a length of 2 mm using a manipulator, and platinum was deposited on one surface of the surface layer. Next, a DC power supply (6614C: Agilent) was connected to the surface on which platinum was deposited, 10V was applied, the free end of the cantilever was brought into contact with the other surface of the surface layer, and a current image was obtained through the AFM body. It was. The measurement was performed at the surface of 100 randomly selected surfaces, and the “volume resistivity” was calculated from the average current value of the top 10 locations of the low current value and the film thickness measured in 5-1. The measurement conditions are shown below.

[Measurement condition]
Measurement mode: contact
Cantilever: CSC17
Measurement range: 10nm x 10nm
Scan rate: 4Hz
Applied voltage: 10V

  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.

(Preparation of substrate)
As a substrate (reference numeral 2 in FIG. 4), a SUS304 core metal having a diameter of 6 mm coated with a primer (trade name, DY35-051; manufactured by Toray Dow Corning) and baked was prepared.

(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-1 in which a silicone rubber elastic layer (reference numeral 3 in FIG. 4) having a diameter of 12 mm was formed on the outer periphery of the base 2 was produced.

(Preparation of surface layer)
The synthesis example for obtaining the polyurethane surface layer (reference numeral 4 in FIG. 4) 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.) 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% by mass, 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.
-Liquid silicone rubber material (trade name, SE6724A / B; manufactured by Toray Dow Corning) 100 parts,
・ 15 parts of carbon black (trade name, Toka Black # 4300; manufactured by Tokai Carbon Co., Ltd.)
-0.2 parts of silica powder as heat resistance imparting agent,
-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% 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 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 3 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. The physical properties of the large particle size silica particles 2 are shown in Table 1.

<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 heated for 3 hours and then taken out and pulverized to obtain small-diameter silica particles 1. 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 (triethanolamate))
2 parts

  Next, the reaction was carried out under reduced pressure of 5 to 20 mmHg, and when the acid value became 0.1 or less, it was cooled to 180 ° C., 15 parts of trimellitic anhydride was added, and the reaction was taken out for 2 hours under atmospheric pressure sealing. After cooling to 0, pulverization gave polyester resin 1. 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 11500 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.

<Production Example of Toner Particle 2>
[Synthesis of Amorphous Polyester Resin (1)]
-136 parts of dimethyl terephthalate-44 parts of adipic acid-10 parts of trimellitic anhydride-304 parts of bisphenol A propylene oxide 2 mol adduct-0.8 parts dibutyltin oxide 0.8 parts In a flask purged with nitrogen at 170 ° C The reaction was performed for 4 hours. Furthermore, it was made to react at 200 degreeC under pressure reduction, water and methanol were removed, and the amorphous polyester resin (1) which is a nonlinear polyester resin was obtained.

[Synthesis of Crystalline Polyester Resin (1)]
-Sebacic acid 100 mol part-1,9-nonanediol 110 mol part-Dibutyltin oxide 0.031 mol part The above material was put into a flask purged with nitrogen, and reacted at 170 ° C for 4 hours and further under reduced pressure at 200 ° C for 0.5 hour, A crystalline polyester resin (1) having a melting point of 70 ° C. was obtained.

[Preparation of Binder Resin Fine Particle Dispersion (1)]
100 parts of the amorphous polyester resin (1) was dissolved in 150 parts of tetrahydrofuran. While stirring this tetrahydrofuran solution at 10000 rpm for 2 minutes with a homogenizer (IKA Japan: Ultra Tarax) at room temperature, ion-exchanged water 1000 containing 5 parts of potassium hydroxide and 10 parts of sodium dodecylbenzenesulfonate as a surfactant was added. The part was dripped. The mixed solution was heated to about 75 ° C. to remove tetrahydrofuran. Then, it diluted with ion-exchange water so that solid content might be 8%, and the binder resin fine particle dispersion (1) with a volume average particle diameter of 0.09 micrometer was obtained.

[Preparation of Binder Resin Fine Particle Dispersion (2)]
A binder resin fine particle dispersion (2) was obtained in the same manner except that the amorphous polyester resin (1) was replaced with the crystalline polyester resin (1) in the preparation of the binder resin fine particle dispersion (1). .

[Preparation of magnetic fine particle dispersion (1)]
・ Magnetic 1 49 parts ・ Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 1 part ・ Ion-exchanged water 250 parts ・ Glass beads (diameter 1 mm) 250 parts (Toyo Seiki) dispersed for 3 hours, and the glass beads were removed with a nylon mesh. Then, it diluted with ion-exchange water so that solid content might be 15%, and obtained the magnetic body fine particle dispersion (1).

[Preparation of Release Agent Fine Particle Dispersion (1)]
・ 200 parts of polyethylene wax (PW850, manufactured by Toyo Petroleum)
・ 10 parts of ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku)
-Ion exchange water 630 parts After heating the above to 130 degreeC, it stirred at 10,000 rpm for 2 minutes with the homogenizer (the product made by IKA Japan: Ultratarax), and cooled to 50 degreeC after that. Then, it diluted with ion-exchange water so that solid content might be 20%, and mold release agent fine particle dispersion (1) was obtained.

[Preparation of Charge Control Agent Fine Particle Dispersion (1)]
20 parts of dialkyl salicylic acid metal compound (charge control agent, Bontron E-84, manufactured by Orient Chemical Industries)
・ Anionic surfactant 2 parts (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC)
-Ion-exchanged water 78 parts The above was mixed, and the charge control agent fine particle dispersion liquid (1) obtained by stirring at 10,000 rpm for 2 minutes with a homogenizer (manufactured by IKA Japan: Ultra Tarax) was obtained.

[Production of Toner Particles 2]
-Binder resin fine particle dispersion (1) 80 parts-Binder resin fine particle dispersion (2) 20 parts-Magnetic substance fine particle dispersion (1) 63 parts-Release agent fine particle dispersion (1) 20 parts-Charge control Agent fine particle dispersion (1) 20 parts The above was sufficiently mixed and dispersed in a round stainless steel flask with a homogenizer (manufactured by IKA Japan: Ultra Tarax). Thereafter, 0.4 part of polyaluminum chloride was added to this dispersion, and the dispersion operation was continued with a homogenizer (manufactured by IKA Japan: Ultra Tarax). Next, while stirring the flask in a heating oil bath, the flask was heated to 50 ° C. and held for 60 minutes. In the subsequent melting step, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal at 100 ° C. And heated for 5 hours. Then, after cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain toner particles 2 having a weight average particle diameter of 7.9 μm.

<Production Example of Toner Particle 3>
The weight average particle size is 8.1 μm in the same manner as in the production example 1 of the toner particle 1 except that the rotation speed of the production example of the toner particle 1 in the TK homomixer (Special Machine Industries Co., Ltd.) is 8500 rpm. Toner particles 3 were obtained.

<Production Example of Toner Particle 4>
71.0 parts of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 28.0 parts of terephthalic acid, 1.0 part of trimellitic anhydride and 0.5 part of titanium tetrabutoxide The flask was placed in a glass 4-liter four-necked flask, and a thermometer, a stirring rod, a condenser and a nitrogen inlet tube were attached and placed in a mantle heater. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the mixture was reacted at a temperature of 200 ° C. for 4 hours to obtain a polyester resin 1-1. The polyester resin 1-1 had a weight average molecular weight (Mw) of 80000, a number average molecular weight (Mn) of 3500, and a peak molecular weight (Mp) of 5700.

  Also, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 70.0 parts, terephthalic acid 20.0 parts, isophthalic acid 3.0 parts, trimellitic anhydride 7.0 parts In addition, 0.5 part of titanium tetrabutoxide was placed in a 4-liter 4-neck flask made of glass, and a thermometer, a stir bar, a condenser and a nitrogen inlet tube were attached and placed in a mantle heater. Next, after replacing the inside of the flask with nitrogen gas, the temperature was gradually raised while stirring, and the mixture was reacted at 220 ° C. for 6 hours to obtain polyester resin 1-2. This polyester resin 1-2 was the weight average molecular weight (Mw) 120,000, the number average molecular weight (Mn) 4000, and the peak molecular weight (Mp) 7800.

  The polyester resin 1-1: 50 parts and the polyester resin 1-2: 50 parts were premixed with a Henschel mixer (Mitsui Miike Chemical Co., Ltd.), and a melt kneader (PCM-30 type, Ikegai Iron Works Co., Ltd.) Was subjected to melt blending under the conditions of a rotation speed of 3.3 s-1 and a kneading resin temperature of 100 ° C. to obtain a binder resin 1.

Next, styrene 64.0 parts, n-butyl acrylate 13.5 parts, acrylonitrile 2.5 parts or more were charged into an autoclave, and the system was replaced with N ₂ , and then maintained at 180 ° C. while stirring at elevated temperature. 50 parts of a 2% by mass t-butyl hydroperoxide xylene solution was continuously dropped into the system for 5 hours, and after cooling, the solvent was separated and removed to obtain a polymer A. When the molecular weight of the polymer A was measured, the weight average molecular weight (Mw) was 7000 and the number average molecular weight (Mn) was 3000.

-Binder resin 1 100 parts-Polymer A 2 parts-Fischer-Tropsch wax 4 parts (peak temperature of maximum endothermic peak 105 ° C)
・ 95 parts of magnetic material 1 ・ 2 parts of monoazo iron compound (T-77, Hodogaya Chemical Co., Ltd.)
After mixing the above prescription with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.), a biaxial kneader (PCM-30 type, manufactured by Ikekai Tekko Co., Ltd.) set at a temperature of 130 ° C. Kneaded. The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material. The obtained coarsely crushed material was pulverized with a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.). Furthermore, classification was performed by a multi-division classifier using the Coanda effect to obtain resin particles. The obtained resin particles had a weight average particle diameter (D4) of 6.3 μm.

Using a mechanical classification simultaneous spheronization processing device (Faculty, manufactured by Hosokawa Micron Corporation) for these resin particles, while removing fine particles at a classification rotor rotation speed of 120 s ⁻¹ , a dispersion rotor rotation speed of 100 s ⁻¹ (rotational peripheral speed) Was 130 m / sec) for 60 seconds to obtain toner particles 4 having a weight average particle diameter (D4) of 6.7 μm.

<Production Example of Toner 1>
Using a Henschel mixer FM10C (Mitsui Miike Chemical Co., Ltd.), 100 parts of toner particles 1 and 0.3 part of large particle size silica particles 1 were used to perform a pre-external addition mixing step. 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.

The apparatus shown in FIG. 2 has a configuration in which the diameter of the inner peripheral portion of the main casing 41 is 130 mm and the volume of the processing space 49 is 2.0 × 10 ⁻³ m ³ . The rated power was 5.5 kW, and the shape of the stirring member 43 was that of FIG. The overlapping width d of the stirring member 43a and the stirring member 43b in FIG. 3 is 0.25D with respect to the maximum width D of the stirring member 43, and the clearance between the stirring member 43 and the inner periphery of the main body casing 41 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 16>
Toners 2 to 16 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, the external addition conditions, etc. shown in Table 2 were changed. Table 3 shows the physical properties of Toner 2 to 16 obtained.

<Production of charging roller>
<Preparation of unvulcanized rubber composition>
The materials of the types and amounts shown in Table 4 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%.

(Adjustment 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 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 manufactured 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 , the outermost binder resin of the surface layer is decomposed, and the conductive minute convex portions are formed. Formed. 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 to 11>
The charging rollers 2 to 11 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 6. In addition, as raw materials of the coating liquid described in Table 6, (A) hydroxyl group-terminated prepolymer (polyol), (B) isocyanate group-terminated prepolymer (isocyanate), (C) roughened particles are shown in Tables 5-1 to 5- 3. A part of the isocyanate group-terminated prepolymer was reacted in advance with a polyol and polymeric MDI (trade name: Millionate MR200, manufactured by Nippon Polyurethane Industry Co., Ltd.) as shown in Table 5 in the same manner as in the charging roller 1 to obtain an isocyanate group content of 4 What was adjusted to 6% was used.

<Example 1>
(Image forming device)
A Canon printer LBP7700C was remodeled and used for image evaluation. As a modification point, as shown in FIG. 5, the toner supply member of the developing device is rotated in the reverse direction with respect 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, a clear image without fog is obtained even in a cleaner-less and high-humidity environment, and a good image is obtained in a low-temperature and low-humidity environment with good recoverability and no cleaner-less ghost due to poor collection. I was able to.

  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).

[Fog]
A white image was output, and the reflectance was measured using a REFECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku. On the other hand, the reflectance of the transfer paper (standard paper) before white image formation was measured in the same manner. A green filter was used as the filter. The fog was calculated from the reflectance before and after the white image output using the following formula.
Fog (reflectance) (%) = reflectance of standard paper (%)-reflectance of white image sample (%)

The determination criteria for fogging are as follows.
A: Very good level (fogging less than 1.5%)
B: Good level (fog 1.5% to less than 2.5%)
C: Level that is not a problem in practice (fogging 2.5% or more and less than 3.5% or less)
D: Practically unfavorable level (fogging of 3.5% or more)

[Recoverability]
Recoverability forms a solid black image for one round of the electrostatic latent image carrier, passes through the transfer process and charging process, taps the residual toner before passing through the development area, and the density is measured with the Macbeth reflection densitometer. It was measured. The density before tape collection was determined by subtracting the density of only the tape from the density of the remaining toner. Next, it passed through the transfer process, the charging process, and the development area, taped on the electrostatic latent image carrier in the area before the next transfer process, and the density was measured with the Macbeth reflection densitometer. From the density on the electrostatic latent image carrier thus measured, the density of only the tape was subtracted to obtain the post-recovery density.

Using the concentration before recovery and the concentration after recovery, the recoverability was calculated as follows.
Recoverability = 1- (concentration after recovery / concentration before recovery)

The criteria for recoverability are as follows.
A: Recoverability is 0.95 or more, very good B: Recoverability is 0.90 or more and less than 0.95, good C: Recoverability is 0.85 or more and less than 0.90, which is a practical problem No level

<Examples 2 to 8, Examples 17 to 30>
A developing device having a combination of toner and charging roller as shown in Table 7 was prepared, and image output evaluation was performed in the same manner as in Example 1. As a result, good results were obtained in all developing devices in both fogging in a high temperature and high humidity environment and recoverability in a low temperature and low humidity environment. Table 7 shows the evaluation results.

<Reference Examples 1 to 3>
A developing device having a combination of toner and charging roller as shown in Table 7 was prepared, and image output evaluation was performed in the same manner as in Example 1. As a result, an image having no problem in practical use was obtained in all the developing devices in both fogging in a high temperature and high humidity environment and recoverability in a low temperature and low humidity environment. Table 7 shows the evaluation results.

<Comparative Example 1>
A developing device having a combination of toner and charging roller as shown in Table 7 was prepared, and image output evaluation was performed in the same manner as in Example 1. As a result, all of the developing devices had poor recoverability in a low temperature and low humidity environment or fog in a high temperature and high humidity environment. Table 7 shows the evaluation results.

<Example 9>
A Canon printer LBP3100 was modified and used for image evaluation. As a remodeling point, as shown in FIG. 6, the toner carrier was remodeled so as to contact the electrostatic latent image carrier. 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, a clear image without fog is obtained even in a cleaner-less and high-humidity environment, and a good image is obtained in a low-temperature and low-humidity environment with good recoverability and no cleaner-less ghost due to poor collection. I was able to. The evaluation results are shown in Table 8.

<Examples 10 to 16>
A developing device was produced by combining the toner and the charging roller as shown in Table 8, and | V1-V2 | was set as shown in Table 8, and image output evaluation was performed in the same manner as in Example 9.

  As a result, good results were obtained in all developing devices in both fogging in a high temperature and high humidity environment and recoverability in a low temperature and low humidity environment. The evaluation results are shown in Table 8.

  41: main body casing, 42: rotating body, 43, 43a, 43b: stirring member, 44: jacket, 45: raw material inlet, 46: product outlet, 47: central shaft, 48: drive unit, 49: processing space, 410: Rotating body end side surface, 51: Rotating direction, 52: Return direction, 53: Feeding direction, 416: Raw material inlet inner piece, 417: Product outlet inner piece, d: Overlapping portion of stirring member Interval, D: Width of stirring member, 5: Electrostatic latent image carrier (photosensitive member), 7: Toner carrier (developer carrier), 10: Transfer member (transfer charging roller), 6: Charging member (charging) Roller), 14: laser generating device (latent image forming means, exposure device), 12: pickup roller, 11: fixing device, 9: developing device, 18: stirring member, 15: toner regulating member, 17: toner, 13: Transfer paper

Claims (6)

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 exposing means for forming an electrostatic latent image on the surface, 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 device having developing means for forming,
Transfer means for transferring the toner image formed on the surface of the latent electrostatic image bearing member to the transfer material with or without an intermediate transfer member, and the toner image transferred to the transfer material A fixing unit for fixing to the transfer material; and a cleaning unit for removing unnecessary toner on the electrostatic latent image carrier on the downstream side of the transfer unit and the upstream side of the contact-type charging roller. In the image forming apparatus that is not provided and collects the transfer residual toner after the toner image is transferred 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. The toner carrier is disposed opposite the electrostatic latent image carrier, and the contact-type charging roller has a shaft core, an elastic layer, and a surface layer on an outer periphery of the elastic layer, The surface layer has a universal hardness of 1.0 N / mm ² or more and 10.0 N / mm ² or less, and the volume resistivity of the surface layer is 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹⁶ Ωcm or less, The surface layer is made of a resin containing conductive particles, and has fine convex portions by the conductive particles,
The toner is a toner having toner particles containing a binder resin and a colorant and silica fine particles, and the coefficient of static friction of the toner with respect to the polycarbonate resin substrate is 0.100 or more and 0.250 or less. An image forming apparatus. The number of minute convex portions by the conductive particles of 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 according to claim 1.   The coverage X1 of the toner with the fine silica particles obtained by an X-ray photoelectron spectrometer (ESCA) is 50.0 area% or more and 75.0 area% or less. Image forming apparatus. The image according to any one of claims 1 to 3, wherein a diffusion index represented by the following formula 1 satisfies the following formula 2 when a theoretical coverage of the toner by the silica fine particles is X2. Forming equipment.
(Formula 1) Diffusion index = X1 / X2
(Expression 2) Diffusion index ≧ −0.0042 × X1 + 0.62   The image forming apparatus according to claim 1, wherein the toner has an average circularity of 0.960 or more. Electrostatic latent image carrier, contact-type charging roller for charging the electrostatic latent image carrier, and surface of the charged electrostatic latent image carrier by irradiating image exposure light to the electrostatic latent image carrier An image exposure means for forming an electrostatic latent image on the surface of the toner, 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 forming;
A transfer step for transferring the toner image formed on the surface of the latent electrostatic image bearing member to the transfer material with or without an intermediate transfer member, and the toner image transferred to the transfer material. A fixing step for fixing to the transfer material, and a cleaning step for removing unnecessary toner on the electrostatic latent image carrier downstream of the transfer material and upstream of the contact-type charging roller. In the image forming method of recovering residual transfer toner after transferring the toner image 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 opposite to the electrostatic latent image carrier,
The contact-type charging roller has a shaft core, 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 10.0 N / mm ² or less. The volume resistivity of the surface layer is 1.0 × 10 ¹⁰ Ωcm or more and 1.0 × 10 ¹⁶ Ωcm or less,
The surface layer is made of a resin containing conductive particles, and has fine convex portions by the conductive particles,
The toner is a toner having toner particles containing a binder resin and a colorant and silica fine particles, and the coefficient of static friction of the toner with respect to the polycarbonate resin substrate is 0.100 or more and 0.250 or less. An image forming method.

Images