JP2017151287A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method capable of obtaining a uniform half-tone image, while suppressing a non-uniform wear of an image carrier even at a high process speed and under the use environment over a long period.SOLUTION: A charging member includes: a conductive base; and a conductive resin layer 12 as a surface layer on the base. The conductive resin layer 12 includes a binder and is configured to hold ball-like resin particles 11 having an opening in a state that the opening is exposed on the surface of the charging member. The surface of the charging member includes: a recess part originating from the opening of the ball-like resin particles 11 exposed on the surface; and a protrusion part originating from the edge part of the opening of the ball-like resin particles 11 exposed on the surface where a saturation magnetization is not less than 15.0 Am/kg and not more than 35.0 Am/kg in a magnetic field of 795.8 kA/m and the dielectric constant ε' of the toner is the frequency 10 kH and not less than 25.0pF/m and not more than 40.0pF in the temperature 40°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming method used in an electrophotographic system, an electrostatic recording system, an electrostatic printing system, and a toner jet system.

  A charging step of charging the image carrier using a charging member, an electrostatic latent image forming step of forming an electrostatic latent image on the image carrier, and developing the electrostatic latent image with toner to form a toner image An electrophotographic method is known in which an image is obtained through a developing step, a transfer step of transferring the toner image to a recording medium, and the like. Examples of such an image forming apparatus using electrophotography include a copying machine and a printer.

The required performance required for these printers and copiers is increasing year by year, and it is necessary to satisfy performances that tend to conflict with each other, such as compatibility with high speed and high image quality.
In particular, in response to high image quality, correspondence to photographic images and graphic images is required. In these images, there are many images in a so-called halftone region with a small amount of applied toner, and there is a strong demand for suppression of roughness and uniformity.

On the other hand, miniaturization of electrophotographic apparatuses is also required, and in the charging step, the surface of the image carrier is charged by applying a voltage to a charging member that is in contact with or close to the surface of the image carrier. The contact charging method is widely used. As the voltage, a direct current voltage alone or a direct current voltage superimposed with an alternating current voltage is used.
As a charging member, various studies have been made to achieve both high speed and high image quality. For example, Patent Document 1 discloses a charging member for contact charging including a surface layer having a convex portion derived from resin particles on the surface. By using such a charging member, charging of the image carrier is further stabilized.

However, in the charging member described in Patent Document 1, when it comes into contact with the image carrier, the contact pressure is applied to the convex portion derived from the resin particles on the surface of the roller-shaped charging member (hereinafter also referred to as “charging roller”). Becomes easier to concentrate. As a result, in long-term use, uneven wear may occur on the surface of the image carrier, resulting in vertical streak-like image defects.
With respect to this problem, the charging member disclosed in Patent Document 2 contains bowl-shaped resin particles 11 having openings in the conductive resin layer, as shown in (1a) and (1b) of FIG. To do. And the charging member has the uneven | corrugated shape derived from the opening part and edge part of the bowl-shaped resin particle on the surface.

By using the charging member described in Patent Document 2, the edge of the opening of the bowl-shaped resin particles on the surface of the charging member (hereinafter simply referred to as the edge) is elastically deformed, so that The contact pressure is relieved. For the above reasons, it is possible to suppress uneven wear of the image carrier even at high process speeds and long-term use.
As a result, the uniformity of halftone has improved, but in environments where it is used at a higher process speed and for a longer period of time, further improvements are required. is necessary.

  For example, Patent Document 3 proposes a toner that defines the magnetic characteristics and dielectric characteristics of the toner, and the inorganic fine powder added to the toner and the toner that defines the dielectric characteristics of the toner used in the magnetic one-component development system. Yes. According to this, it is described that a high-quality image with excellent dot reproducibility and less fog can be provided. However, there is room for further improvement in solving the above problems in the contact charging system.

JP 2008-276026 A JP 2011-248353 A JP 2005-134751 A

  An object of the present invention is to provide an image forming method capable of obtaining a uniform halftone image while suppressing uneven wear of an image carrier even under a high process speed and a long-term use environment. That is.

The present invention includes a charging step of charging the image carrier using a charging member that contacts the image carrier,
An electrostatic latent image forming step of forming an electrostatic latent image on the image carrier;
A development step of developing the electrostatic latent image with toner to form a toner image;
A transfer step of transferring the toner image to a recording medium with or without an intermediate transfer member, and a step of heating and fixing the toner image transferred to the recording medium;
An image forming method comprising:
The charging member has a conductive substrate and a conductive resin layer as a surface layer on the substrate,
The conductive resin layer contains a binder and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member,
The surface of the charging member includes a concave portion derived from the opening of the bowl-shaped resin particle exposed on the surface, and a convex portion derived from the edge of the opening of the bowl-shaped resin particle exposed to the surface. Have
The saturation magnetization of the toner is 15.0 Am ² / kg or more and 35.0 Am ² / kg or less at a magnetic field of 795.8 kA / m, and the dielectric constant ε ′ of the toner is 25.0 pF / m at a frequency of 10 kHz and a temperature of 40 ° C. The present invention relates to an image forming method characterized by being 40.0 pF / m or less.

  According to the present invention, there is provided an image forming method capable of obtaining a uniform halftone image while suppressing uneven wear of an image carrier even under a high process speed and a long-term use environment. It becomes possible.

10 is an explanatory diagram showing a configuration in the vicinity of the surface of a charging member of Patent Document 2. FIG. FIG. 3 is an explanatory view showing a configuration near the surface of an electrophotographic member (charging member) according to the present invention and a contact state with an image carrier. It is a schematic sectional drawing which shows an example of the charging member which concerns on this invention. It is the schematic of the electric current measurement apparatus of a charging member. It is a fragmentary sectional view near the surface of the charging member according to the present invention. It is a fragmentary sectional view near the surface of the charging member according to the present invention. It is explanatory drawing of the shape of the bowl-shaped resin particle used for this invention. It is a schematic sectional drawing which shows an example of the charging member which concerns on this invention. It is a schematic sectional drawing which shows an example of the charging member which concerns on this invention. It is explanatory drawing of the mode of oxygen permeation at the time of heat processing the charging member which concerns on this invention. It is the schematic which shows one Embodiment of the scanning electron microscope for calculating the brightness | luminance resulting from electrical conductivity. 1 is a schematic cross-sectional view illustrating an example of an electrophotographic apparatus according to the present invention. It is a schematic sectional drawing showing an example of the process cartridge which concerns on this invention. 2 is a TEM photograph of magnetic particles (G-1) for toner according to the present invention. (Make black and white) It is a figure which shows the measuring method of the height of the convex part of the magnetic particle which concerns on this invention.

In the image forming method using the contact charging method, the present inventors obtain a uniform halftone image while suppressing uneven wear of the image carrier even under a high process speed and a long-term use environment. The image forming method that can be used was studied.
In the contact charging method, the surface of the image carrier is charged by applying a voltage (a voltage of only a DC voltage or a voltage in which an AC voltage is superimposed on a DC voltage) to a charging member that is in contact with or close to the surface of the image carrier. It is a method to do.

For this reason, the surface of the image carrier is likely to be worn during high-speed process speed and long-term use, and vertical streak-like image defects may occur due to the wear.
In addition, since it rotates at high speed, when the charging member is driven to rotate, the driven rotational property is likely to be lowered between the charging member and the image carrier. May occur.

  In order to improve the followability of the charging member, it is effective to improve the frictional property by providing irregularities on the surface of the charging member. As an example of forming irregularities on the surface of the charging member, irregularities can be formed by using a surface layer having convex portions derived from resin particles or the like on the surface, such as Patent Document 1 described above. However, when contacted with the image carrier, the contact pressure concentrates on the convex portions derived from the resin particles on the surface of the charging roller, so that uneven wear occurs on the surface of the image carrier over a long period of use. In some cases, vertical streak-like image defects may occur.

  On the other hand, the above-mentioned problem can be solved by using a charging member having irregularities derived from bowl-shaped resin particles on the surface. That is, the charging member used in the present invention has a conductive substrate and a conductive resin layer as a surface layer on the substrate. The conductive resin layer includes a binder and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member. Furthermore, the surface of the charging member has a recess derived from the opening of the bowl-shaped resin particles exposed on the surface and a protrusion derived from the edge of the opening of the bowl-shaped resin particles exposed on the surface. And a portion.

  By using the charging member having the above-described configuration, irregularities are formed on the surface of the charging member, so that the followability is improved even at a high process speed. In addition, the edge of the opening of the bowl-shaped resin particles on the surface of the charging member is elastically deformed, so that the contact pressure on the image carrier is relieved. For the above reasons, it is possible to suppress uneven wear of the image carrier even at high process speeds and long-term use.

As a result, the uniformity of the halftone has been greatly improved, but in an environment where it is used at a higher process speed and for a longer period of time, further improvement has been demanded. The present inventors have intensively studied an image forming method capable of obtaining a more uniform halftone image.
As a result, it has been found that by using the following toner, a uniform halftone image can be obtained even in a higher process speed and a longer usage environment.
That is, the toner used in the image forming method of the present invention is characterized by the following (1) and (2).

(1) the saturation magnetization of the toner in a magnetic field 795.8 kA / m is less 15.0Am ² / kg or more 35.0Am ² / kg, more preferably, 20.0Am ² / kg or more 30.0Am ² / kg or less.
(2) The dielectric constant ε ′ of the toner at a frequency of 10 kHz and a temperature of 40 ° C. is 25.0 pF / m or more and 40.0 pF / m or less, more preferably 27.0 pF / m or more and 35.0 pF / m or less. .

  Electrophotographic development methods are roughly classified into a two-component development method using carrier particles and a one-component development method using no carrier particles. The one-component development method does not have a carrier as compared with the two-component development method, so that maintenance of agent replacement can be omitted. Further, it is possible to omit means for detecting and correcting the ratio between the toner and the carrier, and it is preferably used in applications that require high reliability and maintenance-free.

In copying machines and printers, downsizing and energy saving of devices are progressing, and a magnetic one-component developing system using magnetic toner that is advantageous in these respects is preferably used.
In the magnetic one-component developing method, a magnetic toner layer is formed by a magnetic toner layer regulating member on a toner carrier (hereinafter also referred to as a developing sleeve) provided with a magnetic field generating means such as a magnet roll. This magnetic toner layer is transported to a development area by a developing sleeve and developed.

In the magnetic one-component development method, since the toner coat layer is formed on the developing sleeve using magnetic force, so-called toner spikes in which the magnetic toner is linked in a bead shape along the magnetic field lines of the magnetic field generating means inside the developing sleeve. Forming a standing.
Since this magnetic toner layer is transported to a development area by a developing sleeve and developed, the magnetic one-component developing system tends to develop the toner in a state in which the spikes are maintained.

The present inventors use a toner having a specific saturation magnetization and a dielectric constant, and use a charging member having irregularities derived from bowl-shaped resin particles on the surface as a charging member, so that a higher process speed and It has been found that a more uniform halftone image can be obtained even in a longer-term use environment.
By using a charging member having irregularities derived from bowl-shaped resin particles on the surface, the image carrier is suppressed from uneven wear, and the followability between the image carrier and the charging member is improved. A denser latent image can be formed, and halftone uniformity can be improved.
In the magnetic one-component development system, a uniform halftone image can be obtained up to a certain process speed without depending on the state of the heading.
However, with a higher process speed configuration, there are fewer opportunities for development. Therefore, it is necessary to appropriately control the rising state and develop a dense latent image efficiently.

There are various factors that determine the shape of the ears, but the saturation magnetization of the toner is an index that represents the magnetic properties of the toner, and is a factor that determines the shape and size of the ears on the developing sleeve.
On the other hand, the dielectric constant is an index representing the charging characteristics of the toner.
In general, in the magnetic one-component development system, the developing sleeve and the image carrier are often not in contact with each other.
For this reason, it is considered that the magnetic action is weakened against the toner spikes away from the developing sleeve, and conversely, the electrostatic action is dominant.
In addition, since a developing bias is applied during development, it is considered that the state of spikes is dominated by the dielectric properties of the toner.

As a result of intensive studies, the present inventors have found that, when the dielectric constant and saturation magnetization of the toner are controlled within the scope of the present application, during the development, the spikes can efficiently fly from the developing sleeve, and the development during the flight can be easily performed. The bias makes it easy to disperse the ears, and it becomes possible to faithfully reproduce the dense latent image formed by the charging member of the present application.
It has been found that these effects are remarkably exhibited especially under the condition of a high process speed such that the process speed exceeds 380 mm / sec, and the effect continues through durability.

Furthermore, the inventors have controlled both the dielectric constant and the saturation magnetization within a specific range, so that the electric polarization is controlled by the magnetic field produced by the toner due to the interaction such as the electromagnetic effect, and the dielectric constant falls within the scope of the present application. They also found that they tend to be easier to control.
As a result of the above, it is considered that a more uniform halftone image can be obtained even in an environment where the process speed is higher than in the past and the environment is used for a long time.
The saturation magnetization amount of the toner of the present invention is controlled by the magnetization amount and the content of magnetic iron oxide contained in the toner.

Further, the dielectric constant of the toner can be adjusted by selecting the binder resin, the type of magnetic particles, the content of magnetic particles, and the like.
FIG. 3 shows a circumferential cross section of a charging roller as an embodiment of the charging member according to the present invention.
As shown in FIG. 3 (3 a), the charging roller has a conductive substrate 1 and a conductive resin layer 2. Alternatively, as shown in FIG. 3 (3 b), the charging roller has a substrate 1, a conductive resin layer 21 as an intermediate layer on the substrate, and a conductive resin layer 22 as a surface layer on the intermediate layer. The conductive resin layer as the surface layer contains a binder.

FIG. 2 is a view showing the vicinity of the surface of the charging member. As shown in FIG. 2, a conductive resin layer (binder) 12, a bowl recess 17 and a bowl projection 18 are present on the surface of the electrophotographic member.
More specifically, as shown in FIG. 2 (2a), the conductive resin layer 12 as the surface layer is formed so that the bowl-shaped resin particles 11 having openings are exposed on the surface of the charging member. keeping. And the surface of the charging member is
A binder,
A concave portion derived from the opening of the bowl-shaped resin particles 11 exposed on the surface (hereinafter, sometimes simply referred to as “a concave portion of the bowl”);
A convex portion derived from the opening edge of the bowl-shaped resin particle 11 (hereinafter sometimes simply referred to as “bowl edge”) (hereinafter simply referred to as “bowl convex portion”); ing.

Further, the charging member of the present invention has a conductive base and a conductive resin layer as a surface layer on the base, and the conductive resin layer includes a binder and has a bowl shape having an opening. The resin particles are held in a state where the opening is exposed on the surface of the charging member,
The surface of the charging member has a concave portion derived from the opening of the bowl-shaped resin particles exposed on the surface and a convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed to the surface. Have.
A part of the surface of the charging member is constituted by the conductive resin layer, and the conductive resin layer heats the layer of the conductive heat-crosslinkable rubber composition containing conductive fine particles in the presence of oxygen. It is preferably formed by crosslinking.

  Further, it is preferable that a part of the surface of the charging member is constituted by the conductive resin layer and that the conductive fine particles are present in the concave portion.

Further, a part of the surface of the charging member is constituted by the conductive resin layer,
The surface of the charging member is applied with an accelerating voltage of 1 kV and a magnification of 2000 using a scanning electron microscope in a state where a direct current voltage of 50 V or more and 100 V or less is applied between the electrode opposed to the charging member and the substrate. Observe at double,
When the luminance at the convex portion is K1, the luminance at the bottom of the concave portion is K2, and the luminance at the exposed surface of the conductive resin layer is K3, K1, K2 and K3 are represented by the following formulas (1) to (3 ) Is preferably satisfied.
Formula (1) K2 <K1
Formula (2) K3 <K1
Formula (3) 0.8 <= K2 / K3 <= 1.2.

  In the present invention, the luminances K1 to K3 are calculated by observing from above the surface of the charging member (the Z direction in FIG. 2 (2a)). The luminance K2 is the luminance due to the electrical conductivity of the portion including the bowl-shaped resin particles and the binder located immediately below the bowl-shaped resin particles. By measuring this brightness K2, it is possible to accurately evaluate the state of discharge from the bottom of the bowl recess. The brightness K2 can be calculated by appropriately setting the acceleration voltage of the electron microscope.

  The luminance of the present invention is correlated with the conductivity of the observation site. That is, the lower the luminance, the higher the conductivity, and the higher the luminance, the lower the conductivity. Formula (1) indicates that the conductivity EC1 of the convex portion of the bowl is lower than the conductivity EC2 of the bottom of the concave portion of the bowl. Equation (2) shows that the conductivity EC1 of the convex portion of the bowl is lower than the conductivity EC3 of the binder exposed on the surface. When the charging member comes into contact with the image carrier, the electrical conductivity EC1 of the convex portion of the bowl that is in contact with the surface of the image carrier is low, so that an electrical connection is established between the surface of the image carrier and the convex portion of the bowl. It becomes possible to maintain attraction.

  Hereinafter, the electric attractive force acting between the surface of the image carrier and the convex portion of the bowl will be described. In the charging member having a concavo-convex shape derived from the opening of the bowl-shaped resin particles exposed on the surface of the charging member, the convex portion 18 of the bowl is not in contact with the image carrier as shown in FIG. It contacts the image carrier 15 while undergoing elastic deformation. On the other hand, when an electrophotographic image is formed, a voltage is applied to the charging member, so that the charging member charges the image carrier by discharge in a minute gap from the image carrier.

  This discharge is a so-called Townsend discharge that is generated when the air between the minute gaps is ionized. At that time, positive and negative charged particles generated by ionizing molecules in the air are guided to the surface of the image carrier or the charging member by an electric field formed between the minute gaps. Then, the charged particles are guided to the image carrier to charge the surface of the image carrier. Further, charged particles having a polarity opposite to that of the charged particles induced by the image carrier are also induced and charged on the charging member. When the conductivity EC1 of the convex portion of the bowl is low, the charge induced by the Townsend discharge on the surface of the charging member is charged up. Due to this charged-up charge, an electric attractive force acts between the image carrier 15 and the convex portion of the bowl, and the attraction between the charging member and the image carrier is strengthened.

  In the charging member of the present invention, as described above, an electric attractive force is likely to act between the image carrier and the convex portion of the bowl. As a result, even in a harsh environment where the rotation and stop such as intermittent mode are repeated at a high process speed, the driven rotation performance is improved, and the peripheral speed of rotation differs between the charging member and the image carrier. The phenomenon (stick slip) that appears irregularly is suppressed.

  In addition to the above, the charging member of the present invention satisfies the formula (3). K2 / K3 in Expression (3) is a ratio of luminance due to the conductivity EC2 at the bottom of the concave portion 17 of the bowl and the conductivity EC3 in the binder 12 exposed on the surface in FIG. 2 (2a). The closer this value is to 1, the closer the electrical conductivity EC2 at the bottom of the bowl recess and the electrical conductivity EC3 at the binder exposed on the surface, and thus the concentration of the electric field on the binder 12 exposed at the surface. It is possible to alleviate and suppress the abnormal discharge described above. As a suitable means for setting the value of K2 / K3 within the range of the formula (3), bowl-shaped resin particles (the material of the bowl) are made of a material having a low oxygen permeability, and the surface of the charging member is placed in the atmosphere. Means for oxidative curing by heat treatment.

The charging member of the present invention includes, for example, a step of forming a coating layer of a composition in which hollow resin particles are dispersed in a binder on the substrate,
By polishing the surface of the coating layer, a part of the shell of the hollow resin particles is removed to form a bowl shape having an opening, and a recess formed by the opening of the bowl-shaped resin particle and an edge of the opening Forming a convex part; and
It is manufactured through a step of causing the conductive fine particles to exist in the recess.
This will be described in detail below.

<Charging member>
FIG. 3 is a schematic sectional view showing an example of the charging member according to the present invention.
The charging member in FIG. 3 (3 a) has a conductive base 1 and a conductive resin layer 2. As shown in FIG. 3 (3 b), the conductive resin layer may have a two-layer structure of conductive resin layers 21 and 22. The conductive resin layer contains a binder and bowl-shaped resin particles.

  The conductive substrate 1 and the conductive resin layer 2 or the layers sequentially stacked on the conductive substrate 1 (for example, the conductive resin layer 21 and the conductive resin layer 22 shown in FIG. 3 (3b)) are bonded. You may adhere | attach through an agent. In this case, the adhesive is preferably conductive. A well-known thing can be used for a conductive adhesive. Examples of the base of the adhesive include thermosetting resins and thermoplastic resins, and known ones such as urethane, acrylic, polyester, polyether, and epoxy can be used. As a conductive agent for imparting conductivity to the adhesive, it can be appropriately selected from conductive fine particles described in detail later, and one kind can be used alone, or two or more kinds can be used in combination.

[Conductive substrate]
The conductive substrate used in the charging member of the present invention is conductive and has a function of supporting a conductive resin layer provided thereon. Examples of the material include metals such as iron, copper, aluminum, and nickel and alloys thereof (stainless steel, etc.).

[Conductive resin layer]
FIG. 5 is a partial sectional view of the vicinity of the surface of the conductive resin layer constituting the surface layer of the charging member according to the present invention. Some bowl-shaped resin particles 41 contained in the conductive resin layer are exposed on the surface of the charging member. The surface of the charging member has a concave portion 52 derived from the opening 51 of the bowl-shaped resin particles exposed on the surface and a convex portion derived from the edge 53 of the opening of the bowl-shaped resin particles exposed on the surface. And have. The edge 53 can take the shape shown in (5a) and (5b). The shape of the edge 53 is not limited to these.

  The height difference 54 between the apex of the convex portion derived from the edge 53 of the opening of the bowl-shaped resin particle and the bottom of the concave portion 52 defined by the shell of the bowl-shaped resin particle shown in FIG. 6 is 5 μm or more. The thickness is preferably 100 μm or less, particularly 10 μm or more and 80 μm or less. By being within the above range, the point contact of the edge of the bowl at the nip portion can be more reliably maintained. Further, the ratio between the height difference 54 and the maximum diameter 55 of the bowl-shaped resin particles, that is, the [maximum diameter] / [height difference] of the resin particles is preferably 0.8 or more and 3.0 or less. . By being within the above range, the point contact of the edge of the bowl at the nip portion can be more reliably maintained.

  It is preferable that the surface state of the conductive resin layer is controlled as follows by forming the uneven shape. The ten-point average surface roughness (Rzjis) is preferably 5 μm or more and 65 μm or less, and more preferably 10 μm or more and 50 μm or less. The average irregularity (Sm) on the surface is preferably 30 μm or more and 200 μm or less, and more preferably 40 μm or more and 150 μm or less. By making it within the above range, the point contact of the edge of the bowl in the nip portion can be more reliably maintained. The method for measuring the surface ten-point average roughness (Rzjis) and the surface unevenness average interval (Sm) will be described in detail later.

  FIGS. 7A to 7E show an example of bowl-shaped resin particles used in the image forming method of the present invention. In the present invention, the “bowl shape” refers to a shape having an opening 61 and a recess 62 having a rounded opening. As shown in FIGS. 7 (a) and (7b), the “opening” may have a flat edge of the bowl, and as shown in FIGS. 7 (c) to (7e). The edge may have unevenness.

  The maximum diameter 55 of the bowl-shaped resin particles is preferably 10 μm or more and 150 μm or less, and more preferably 20 μm or more and 100 μm or less. The ratio of the maximum diameter 55 of the bowl-shaped resin particles to the minimum diameter 63 of the opening, that is, the [maximum diameter] / [minimum diameter of the opening] of the bowl-shaped resin particles is 1.1 or more. More preferably, it is 0 or less.

  The thickness of the shell around the opening of the bowl-shaped resin particles (the difference between the outer diameter and the inner diameter of the edge) is preferably 0.1 μm or more and 3 μm or less, and more preferably 0.2 μm or more and 2 μm or less. In addition, the “maximum thickness” of the shell is preferably 3 times or less of the “minimum thickness”, more preferably 2 times or less.

[binder]
A known rubber or resin can be used as the binder contained in the conductive resin layer of the present invention. Examples of rubber include natural rubber, a vulcanized product thereof, and synthetic rubber. The following are mentioned as a synthetic rubber. Ethylene propylene rubber, styrene butadiene rubber (SBR), silicone rubber, urethane rubber, isopropylene rubber (IR), butyl rubber, acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butadiene rubber (BR), acrylic rubber, epichlorohydrin rubber And fluororubber.

  As the resin, for example, a resin such as a thermosetting resin or a thermoplastic resin can be used. Among these, fluorine resin, polyamide resin, acrylic resin, polyurethane resin, acrylic urethane resin, silicone resin, and butyral resin are more preferable. These may be used alone or in combination of two or more. Moreover, the monomer which is the raw material of these binders may be copolymerized to form a copolymer. For the reasons described later, styrene butadiene rubber (SBR), butyl rubber, acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butadiene rubber (BR) having a double bond in the molecule and high heat resistance. It is more preferable to use

[Conductive fine particles]
As a measure of the volume resistivity of the conductive resin layer, it is preferably 1 × 10 ² Ωcm or more and 1 × 10 ¹⁶ Ωcm or less in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and is within the above range. Thus, it becomes easier to appropriately charge the image carrier by discharge. Therefore, you may contain well-known electroconductive fine particles in a conductive resin layer. Examples of the conductive fine particles include fine particles of metal oxide, metal, carbon black, and graphite. Moreover, these electroconductive fine particles can be used individually by 1 type or in combination of 2 or more types. As a standard of the content of the conductive fine particles in the conductive resin layer, it is 2 to 200 parts by mass, particularly 5 to 100 parts by mass with respect to 100 parts by mass of the binder.

[Method for forming conductive resin layer]
A method for forming the conductive resin layer is exemplified below. First, a coating layer of a composition in which hollow resin particles are dispersed in a binder is formed on a conductive substrate. Then, by polishing the surface of the coating layer, a part of the shell of the hollow resin particles is removed to form a bowl shape having an opening, and the recess formed by the opening of the bowl-shaped resin particle and the bowl-shaped resin Protrusions are formed by the edges of the particle openings. Hereinafter, the shape including these irregularities is also referred to as “uneven shape by opening of bowl-shaped resin particles”. Next, the conductivity of the material present on the surface of the coating layer is adjusted by applying conductive fine particles to the recesses, or by heat treatment of the coating layer in an oxygen-containing atmosphere.

  Hereinafter, each process of the formation method of a conductive resin layer is demonstrated in detail. In addition, the coating layer before a grinding | polishing process among the said coating layers is called "preliminary coating layer." In addition, the “hollow resin particle shell” in the raw material of the charging member is referred to as “bowl-shaped resin particle bowl” in the charging member in which the bowl-shaped resin particles having openings are formed by the polishing process. .

[Dispersion of resin particles in pre-coating layer]
First, a method for dispersing hollow resin particles in the preliminary coating layer will be described. As one method, a coating film of a conductive resin composition in which hollow resin particles containing a gas are dispersed in a binder is formed on a substrate, and the coating film is dried, cured, or A method for performing crosslinking and the like can be exemplified. In addition, conductive particles can be contained in the conductive resin composition. The material used for the hollow resin particles is preferably a resin having a polar group from the viewpoint of low gas permeability and high resilience, and more preferably a resin having a unit represented by the following chemical formula (4). . In particular, it is more preferable to have both the unit represented by the chemical formula (4) and the unit represented by the chemical formula (8) from the viewpoint of easy control of the polishing properties.

In the chemical formula (4), A is at least one selected from the group consisting of the following chemical formulas (5), (6) and (7). R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In chemical formula (8), R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

  As another method, a method of using a thermally expandable microcapsule that includes an encapsulated substance inside the particle and expands the encapsulated substance by applying heat to form hollow resin particles can be exemplified. In this method, a conductive resin composition in which thermally expandable microcapsules are dispersed in a binder is prepared, and this composition is coated on a conductive substrate, followed by drying, curing, or crosslinking. In the case of this method, the encapsulated substance can be expanded by heat at the time of drying, curing, or crosslinking of the binder used for the preliminary coating layer to form hollow resin particles. At that time, the particle size can be controlled by controlling the temperature condition.

  When using thermally expandable microcapsules, it is necessary to use a thermoplastic resin as a binder. The following are mentioned as a thermoplastic resin. Acrylonitrile resin, vinyl chloride resin, vinylidene chloride resin, methacrylic acid resin, styrene resin, butadiene resin, urethane resin, amide resin, methacrylonitrile resin, acrylic acid resin, acrylic ester resin, methacrylic ester resin. Among these, the use of a thermoplastic resin composed of at least one selected from acrylonitrile resin, vinylidene chloride resin, and methacrylonitrile resin, which has low gas permeability and high resilience, is used for controlling the conductive distribution described later. And more preferable. These thermoplastic resins can be used individually by 1 type or in combination of 2 or more types. Furthermore, these thermoplastic resin monomers may be copolymerized to form a copolymer.

  The substance to be encapsulated in the thermally expandable microcapsule is preferably a substance that expands as a gas at a temperature lower than the softening point of the thermoplastic resin, and examples thereof include the following. Low boiling liquids such as propane, propylene, butene, normal butane, isobutane, normal pentane, and isopentane, and high boiling liquids such as normal hexane, isohexane, normal heptane, normal octane, isooctane, normal decane, and isodecane.

  The heat-expandable microcapsules can be produced by a known production method such as a suspension polymerization method, an interfacial polymerization method, an interfacial precipitation method, or a submerged drying method. For example, in the suspension polymerization method, a polymerizable monomer, a substance to be encapsulated in the thermally expandable microcapsule, and a polymerization initiator are mixed, and this mixture is mixed in an aqueous medium containing a surfactant and a dispersion stabilizer. Examples of the method include suspension polymerization after being dispersed in the solution. A compound having a reactive group that reacts with the functional group of the polymerizable monomer or an organic filler can also be added.

  The following can be illustrated as a polymerization monomer. Acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, vinylidene chloride, vinyl acetate. Acrylic acid ester (methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, isobornyl acrylate, cyclohexyl acrylate, benzyl acrylate), methacrylic acid ester (methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, Isobutyl methacrylate, t-butyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate). Styrene monomer, acrylamide, substituted acrylamide, methacrylamide, substituted methacrylamide, butadiene, ε-caprolactam, polyether, isocyanate. These polymerizable monomers can be used alone or in combination of two or more.

  Although it does not specifically limit as a polymerization initiator, The initiator soluble in a polymerizable monomer is preferable, and a well-known peroxide initiator and an azo initiator can be used. Of these, azo initiators are preferred. Examples of azo initiators are listed below. 2,2'-azobisisobutyronitrile, 1,1'-azobiscyclohexane 1-carbonitrile, 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile. Of these, 2,2'-azobisisobutyronitrile is preferable. When using a polymerization initiator, 0.01-5 mass parts is preferable with respect to 100 mass parts of polymerizable monomers.

  As the surfactant, an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, and a polymer type dispersant can be used. As for the usage-amount of surfactant, 0.01-10 mass parts is preferable with respect to 100 mass parts of polymerizable monomers. Examples of the dispersion stabilizer include the following. Organic fine particles (polystyrene fine particles, polymethyl methacrylate fine particles, polyacrylic acid fine particles and polyepoxide fine particles), silica (colloidal silica), calcium carbonate, calcium phosphate, aluminum hydroxide, barium carbonate, magnesium hydroxide and the like. As for the usage-amount of a dispersion stabilizer, 0.01-20 mass parts is preferable with respect to 100 mass parts of polymerizable monomers.

  The suspension polymerization is preferably performed in a sealed state using a pressure vessel. Moreover, after suspending a polymeric raw material with a disperser etc., it may transfer to a pressure-resistant container and may carry out suspension polymerization, and may be suspended in a pressure-resistant container. The polymerization temperature is preferably 50 ° C to 120 ° C. The polymerization may be performed at atmospheric pressure, but may be performed under pressure (at a pressure obtained by adding 0.1 to 1 MPa to atmospheric pressure) so as not to vaporize the substance to be included in the thermal expansion microcapsule. preferable. After completion of the polymerization, solid-liquid separation and washing may be performed by centrifugation or filtration. In the case of solid-liquid separation or washing, thereafter, drying or pulverization may be performed below the softening temperature of the resin constituting the thermally expanded microcapsule. Drying and pulverization can be performed by a known method, and an air dryer, a normal air dryer, and a Nauta mixer can be used. Further, drying and pulverization can be simultaneously performed by a pulverization dryer. Surfactants and dispersion stabilizers can be removed by repeated washing and filtration after production.

[Method for forming preliminary coating layer]
Then, the formation method of a preliminary coating layer is demonstrated. As a method for forming the preliminary coating layer, a conductive resin composition layer is formed on a conductive substrate by a coating method such as electrostatic spray coating, dipping coating, roll coating, and drying, heating, crosslinking, etc. The method of hardening a layer is mentioned. Moreover, the method of adhere | attaching or coat | covering the sheet | seat shape or tube-shaped layer which formed and hardened | cured the conductive resin composition into the predetermined film thickness with respect to a conductive base | substrate is mentioned. Further, there is a method of forming a preliminary coating layer by placing the conductive resin composition in a mold in which a conductive substrate is disposed and curing it. In particular, when the binder is rubber, the conductive substrate and the unvulcanized rubber composition can be integrally extruded by using an extruder equipped with a cross head. A crosshead is an extrusion die that is used at the tip of a cylinder of an extruder, which is used to form a coating layer for electric wires and wires. Then, after passing through drying, curing, cross-linking, etc., the surface of the preliminary coating layer is polished, and a part of the shell of the hollow resin particles is removed to obtain a bowl shape. As a polishing method, a cylindrical polishing method or a tape polishing method can be used. Examples of the cylindrical polishing machine include a traverse type NC cylindrical polishing machine and a plunge cut type NC cylindrical polishing machine.

(A) When the thickness of the preliminary coating layer is 5 times or less the average particle size of the hollow resin particles When the thickness of the preliminary coating layer is 5 times or less the average particle size of the hollow resin particles, In many cases, convex portions derived from hollow resin particles are formed on the surface. In this case, a part of the convex portions of the hollow resin particles can be deleted to form a bowl shape, thereby forming an uneven shape by opening the bowl-shaped resin particles. In this case, it is more preferable to use a tape polishing method in which the pressure applied to the preliminary coating layer during polishing is relatively small. As an example, the preferable ranges as the polishing conditions for the preliminary coating layer when using the tape polishing method are shown below.

  The abrasive tape is obtained by dispersing abrasive grains in a resin and applying it to a sheet-like substrate. Examples of the abrasive grains include aluminum oxide, chromium oxide, silicon carbide, iron oxide, diamond, cerium oxide, corundum, silicon nitride, silicon carbide, molybdenum carbide, tungsten carbide, titanium carbide, and silicon oxide. The average particle size of the abrasive grains is preferably 0.01 μm or more and 50 μm or less, and more preferably 1 μm or more and 30 μm or less. The average particle size of the abrasive grains is the median diameter D50 measured by centrifugal sedimentation. The preferable range of the count of the polishing tape having the above-mentioned preferable range of abrasive grains is 500 or more and 20000 or less, and more preferably 1000 or more and 10,000 or less. Specific examples of the polishing tape are listed below. MAXIMA LAP, MAXIMA T type (trade name, Reflight Co., Ltd.), RAPICA (trade name, manufactured by Kovacs), microfinishing film, wrapping film (trade name, manufactured by 3M Japan Co., Ltd.), mirror film, wrapping Film (trade name, manufactured by Sankyo Rikagaku Co., Ltd.), Mibox (trade name, manufactured by Mipox Co., Ltd.).

  The feed rate of the polishing tape is preferably 10 mm / min or more and 500 mm / min or less, more preferably 50 mm / min or more and 300 mm / min or less. The pressure applied to the preliminary coating layer of the polishing tape is preferably 0.01 MPa or more and 0.4 MPa or less, and more preferably 0.1 MPa or more and 0.3 MPa or less. In order to control the pressing pressure, a backup roller may be brought into contact with the preliminary coating layer via a polishing tape. Moreover, in order to obtain a desired shape, you may perform a grinding | polishing process over multiple times. The number of rotations is preferably set to 10 rpm or more and 1000 rpm or less, and more preferably set to 50 rpm or more and 800 rpm or less. By setting it as said conditions, the uneven | corrugated shape by opening of a bowl-shaped resin particle can be more easily formed in the surface of a preliminary coating layer. In addition, even if the thickness of a preliminary coating layer is in the said range, the uneven | corrugated shape by opening of a bowl-shaped resin particle can be formed with the method of (b) described below.

(B) When the thickness of the preliminary coating layer is more than 5 times the average particle size of the hollow resin particles When the thickness of the preliminary coating layer exceeds 5 times the average particle size of the hollow resin particles, In some cases, convex portions derived from hollow resin particles are not formed on the surface. In such a case, it is possible to form a concavo-convex shape due to the opening of the bowl-shaped resin particles by utilizing the difference in abrasiveness between the hollow resin particles and the material of the preliminary coating layer. The hollow resin particles have a high resilience because they contain a gas inside. On the other hand, as the binder for the preliminary coating layer, a rubber or resin having relatively low impact resilience and small elongation is selected. Thereby, the preliminary coating layer can be easily polished, and the hollow resin particles can be hardly polished. When the pre-coating layer in the above state is polished, the hollow resin particles are not polished in the same state as the pre-coating layer, and may have a bowl shape in which a part of the shell of the hollow resin particles is removed. it can. Thereby, the uneven | corrugated shape by the opening of a bowl-shaped resin particle can be formed in the surface of a preliminary | backup coating layer. Since this method is a method of forming a concavo-convex shape by utilizing the difference in abrasiveness between the hollow resin particles and the material of the preliminary coating layer, the material (binder) used for the preliminary coating layer is rubber. Is preferred. Among these, it is particularly preferable to use acrylonitrile butadiene rubber, styrene butadiene rubber, or butadiene rubber from the viewpoint of low resilience and small elongation.

[Polishing method]
As a polishing method, a cylindrical polishing method or a tape polishing method can be used. However, since it is necessary to remarkably bring out a difference in the polishing properties of materials, conditions for polishing faster are preferable. From this viewpoint, it is more preferable to use a cylindrical polishing method. Among the cylindrical polishing methods, it is more preferable to use the plunge cut method from the viewpoint that the longitudinal direction of the preliminary coating layer can be simultaneously polished and the polishing time can be shortened. In addition, it is preferable that the spark-out process (polishing process at an intrusion rate of 0 mm / min) that has been conventionally performed from the viewpoint of making the polished surface uniform be as short as possible or not performed. As an example, the rotational speed of the plunge cut type cylindrical grinding wheel is preferably 1000 to 4000 rpm, particularly 2000 to 4000 rpm. The penetration rate into the preliminary coating layer is preferably 5 to 30 mm / min, and more preferably 10 to 30 mm / min. At the end of the intrusion process, a break-in process may be provided on the polished surface, and it is preferable that the intrusion speed is 0.1 or more and 0.2 mm / min or less within 2 seconds. The spark-out process (polishing process at an intrusion rate of 0 mm / min) is preferably 3 seconds or less. The number of rotations is preferably set to 50 rpm or more and 500 rpm or less, and more preferably set to 200 rpm or more. By setting it as the said conditions, the uneven | corrugated formation by opening of a bowl-shaped resin particle can be more easily formed in the surface of a preliminary coating layer.
In the following description, the polished pre-coating layer is simply referred to as “coating layer”.

[Conductivity control method]
The charging member of the present invention satisfies the formulas (1) to (3). K1 to K3 in the formulas (1) to (3) indicate the luminance due to the electrical conductivity of each part on the surface of the charging member. In order to satisfy the formulas (1) to (3), It is preferable to control the electrical conductivity of each part.

First, in order to satisfy the mathematical formulas (1) and (2), the material of the bowl portion of the bowl-shaped resin particles described above may be set to a resin with low conductivity having a volume resistivity of 10 ¹⁰ Ωcm or more. preferable. Then, in order to satisfy | fill said Numerical formula (3), it is preferable to control the electrical conductivity of the binder of a coating layer, and the electrical conductivity of the recessed part derived from a bowl-shaped resin particle. The control of the conductivity can be performed in a step after the above-described polishing step, and this control method will be described in detail below.

  FIG. 8 shows a state after the polishing step. First, as described above, the bowl-shaped resin particles 81 are formed of a material having low conductivity or an insulating material. By doing in this way, the recessed part 83 derived from the bowl-shaped resin particle in FIG. 8 can make electrical conductivity a state lower than the binder part 85 beside the bowl-shaped resin particle.

Subsequently, after the polishing step, the following two methods can be exemplified as the conductivity control means of the coating layer for satisfying Equation (3).
[Method 1] A method in which conductive fine particles are present in recesses derived from bowl-shaped resin particles.
[Method 2] The bowl-shaped resin particle bowl material has an oxygen permeability of 140 cm ³ / (m ² ·
24 h · atm) A method of heat-treating the surface of the coating layer in an oxygen-containing atmosphere (such as an air atmosphere) as a material having a low oxygen permeability.

[Method 1] will be described with reference to FIG. When the conductive fine particles 16 are applied to the recesses 17 derived from the bowl-shaped resin particles 11, the conductivity of the recesses 17 can be increased. Then, by selecting the type of the conductive fine particles 16 to be applied, it is possible to control the value of K2 / K3 within the range satisfying Expression (3). As the conductive fine particles to be applied, the above-mentioned conductive fine particles can be used. However, it is preferable to use conductive fine particles having a volume resistivity of 10 ⁰ to 10 ⁸ Ω · cm, and 10 ² to 10 ⁵ Ω. -Conductive fine particles of cm are more preferable. In addition, resin used for a binder is not specifically limited.

  [Method 2] will be described with reference to FIGS. In the heat treatment under an oxygen-containing atmosphere, the degree of cross-linking of the resin increases due to the progress of oxidative cross-linking. Accordingly, the conductivity of the resin tends to decrease. This is because the molecular mobility decreases as the oxidative crosslinking proceeds. The degree of oxidative crosslinking can be adjusted by the heat treatment temperature and the oxygen concentration in the crosslinked part. As for the heating temperature, the higher the temperature, the higher the degree of cross-linking. As for the oxygen concentration, the higher the oxygen concentration in the cross-linking part, the more oxidative cross-linking can proceed. Therefore, by controlling the heating temperature and the oxygen concentration in the resin, it is possible to control the conductivity of the binder portion 85 on the side of the bowl-shaped resin particles and the bottom portion 84 of the bowl-shaped resin particles in FIG. It becomes possible. At this time, as a technique for controlling the oxygen concentration in the resin, it is useful to adjust the oxygen permeability of the bowl-shaped resin particles in the bowl.

In a general heat treatment, oxidative crosslinking proceeds from the surface of the coating layer in the direction inside the coating layer (the direction of the arrow Z2 in FIG. 10).
When the oxygen permeability of the bowl-shaped resin particles is low, the oxygen transmission is blocked by the bowl-shaped resin particles 81 as shown in FIG. Thus, the oxidative cross-linking of the direct lower portion 84 is suppressed. As a result, the conductivity of the direct lower portion 84 is higher than the conductivity of the binder portion 85. Therefore, the conductivity value of the recess 83 in FIG. 8 and the conductivity value of the binder portion 85 tend to be close, and the value of K2 / K3 in Equation (3) becomes close to 1.

  On the other hand, when the oxygen permeability of the bowl-shaped resin particles is high, the bowl-shaped resin particles 81 transmit oxygen as shown in FIG. Oxygen is supplied, and oxidation crosslinking proceeds in the lower part 84 in the same manner as the binder part 85. Therefore, the conductivity value of the direct lower portion 84 and the conductivity value of the binder portion 85 are approximately the same, and the conductivity value of the concave portion 83 and the conductivity value of the binder portion 85 in FIG. 8 are heated in an air atmosphere. Even if the processing is performed, the value does not become close, and the value of K2 / K3 in Equation (3) does not become close to 1.

As described above, forming a bowl of bowl-shaped resin particles with a material having low oxygen permeability can be said to be very useful as a method for controlling the conductivity of the present invention.
Therefore, as the material for forming the bowl of bowl-shaped resin particles, acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin, methyl methacrylate resin, and copolymers of these resins, which have low oxygen gas permeability, are used. It is preferable. In particular, it is more preferable to use an acrylonitrile resin or a vinylidene chloride resin. Thereby, the above-described conductivity control can be more easily performed.

  On the other hand, changing the temperature of the heat treatment can also control the degree of oxidative crosslinking and is a useful technique for controlling the conductivity. However, the progress of oxidative crosslinking by heating is accelerated as the temperature increases, but at the same time, shrinkage due to volatilization of low molecular components of the binder occurs. When the above phenomenon occurs, there is a tendency that the conductivity of the surface of the charging member is greatly increased due to the dense conductive fine particles dispersed in the binder, and this prevents the expression (3) from being satisfied. There is. Therefore, the heating temperature is preferably controlled to 180 to 210 ° C, more preferably 190 to 200 ° C.

  In addition, about the method of heat processing, although well-known means, such as a hot-air continuous furnace, oven, a near-infrared heating method, a far-infrared heating method, can be used, it coat | covers by oxygen-containing atmosphere (in presence of oxygen). The technique is not particularly limited as long as the surface of the layer can be heat-treated.

  The resin as the binder is preferably a resin that promotes the effect of oxidative crosslinking when heated in an oxygen-containing atmosphere. Specifically, styrene butadiene rubber (SBR), butyl rubber, acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butadiene rubber (BR) having a double bond in the molecule and high heat resistance are used. It is preferable to do. The conductive resin layer preferably includes a crosslinked rubber as a binder and is formed by thermally crosslinking a layer of a conductive thermally crosslinkable rubber composition including conductive fine particles in the presence of oxygen.

  The method for forming the conductive resin layer has been described above. Examples of the method for manufacturing the charging member according to the present invention are as follows [1] to [5].

[1] forming a coating layer of a composition in which hollow resin particles are dispersed in a binder on a conductive substrate;
By polishing the surface of the coating layer, a part of the shell of the hollow resin particles is removed to form a bowl shape having an opening, and a recess formed by the opening of the bowl-shaped resin particle and a protrusion formed by the edge of the opening. Forming a portion, and
A method for producing a charging member, comprising the step of causing conductive fine particles to be present in the recess.

  [2] A method for producing a charging member, comprising a step of re-polishing the surface of the coating layer after the step of causing the conductive fine particles to be present.

[3] A step of forming a coating layer of a heat-crosslinkable rubber composition containing conductive fine particles, heat-crosslinkable rubber, and hollow resin particles on the substrate;
By polishing the surface of the coating layer, a part of the shell of the hollow resin particles is removed to form bowl-shaped resin particles having an opening, and the bowl is exposed to the surface. Forming a layer in which shaped resin particles are held, and
The heat-crosslinkable rubber in the coating layer is heat-crosslinked in the presence of oxygen, and has a concave portion derived from the opening and a convex portion derived from the edge of the opening on the surface. A charging member having a step of obtaining a charging member having a conductive resin layer.

[4] The method for producing a charging member according to any one of [1] to [3], wherein the oxygen permeability of the shell of the hollow resin particles is 140 cm ³ / (m ² · 24 h · atm) or less.
[5] The method for producing a charging member according to any one of [1] to [4], wherein a volume resistivity of the shell of the hollow resin particles is 10 ¹⁰ Ωcm or more.

<Toner>
Hereinafter, the toner used in the image forming method of the present invention will be described in detail.
[Magnetic particles for toner]
Examples of the magnetic particles contained in the magnetic one-component toner include the following. Magnetic iron oxide including magnetic iron oxides such as magnetite, maghemite, ferrite, and other metal oxides; metals such as Fe, Co, Ni, or these metals and Al, Co, Cu, Pb, Mg, Ni , Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, alloys with metals such as V, and mixtures thereof.

Among these, magnetic particles satisfying the following 1) to 5) are preferable.
1) A magnetite particle is used as a core, and a coating layer as an outermost layer is provided on the surface of the magnetite particle.
2) The coating layer contains an oxide containing iron and at least one oxide selected from the group consisting of an oxide containing silicon and an oxide containing aluminum.
3) The magnetite particles have an octahedral shape, and have a convex portion in a plane portion constituting the octahedron.

4) The coating layer covers the entire surface of the magnetite particles uniformly, or covers the surface of the magnetite particles partially exposed. In any coating mode, the coating layer covers the surface of the magnetite particle thinly. The thickness of the coating layer is preferably 1 nm or more and 50 nm or less, and more preferably 2 nm or more and 20 nm or less.
5) The coating layer contains an oxide containing iron and an oxide containing silicon or aluminum.

When the magnetic particles are observed with a TEM (transmission electron microscope) by the method described in the examples, the convex portion protrudes when the plane portion of the octahedron is used as a base surface as shown in FIG. It refers to the part that is.
In the present invention, a protrusion having a protruding height of 1 nm or more when the octahedral planar portion is used as a base surface is regarded as a convex portion.
The height of the convex portion is preferably 1 nm or more and 40 nm or less, and more preferably 3 nm or more and 20 nm or less.
The convex part may exist in the plane part of the octahedron without a gap, or may exist sparsely. Although the number of convex portions is not particularly limited, it is sufficient that at least one convex portion is provided for one magnetic particle.

In order for the magnetic particle of the present invention to have a convex portion in the octahedral plane portion, the molar ratio of silicon to iron in the coating layer is preferably 0.2 or more and 1.0 or less, and 0.3 or more and 0 or less. .9 or less is particularly preferable. The molar ratio of aluminum to iron is preferably 0.5 or more and 2.0 or less, and particularly preferably 0.5 or more and 1.8 or less.
The height of the convex portion can be adjusted by changing the above-mentioned molar ratio of silicon to iron in the coating layer, the molar ratio of aluminum to iron, and the number average particle diameter of the core particles.

The proportions of these elements can be measured by the following methods 1) to 3).
1) The coated magnetite particles of the present invention are suspended in 5% by mass dilute sulfuric acid at 50 ° C. to obtain a measurement solution.
2) A part of the measurement liquid is sampled at regular intervals, and this is filtered with a membrane filter.
3) The concentrations of silicon, aluminum and iron contained in the obtained filtrate are quantified with an ICP (Inductively Coupled Plasm) emission spectroscopic analyzer.
In this measurement, the amount of iron dissolved until silicon and aluminum are no longer detected is regarded as the amount of iron in the coating layer.

By using magnetic iron oxide particles having convex portions on the flat surface of the octahedron, the dispersion of magnetic particles in the toner is improved, and variations in the dielectric constant and saturation magnetization of each toner are reduced, so that it can be used over a long period of time. In this case, a uniform halftone image can be stably obtained.
The toner used in the image forming method of the present invention preferably contains 30 to 70 parts by mass of magnetic particles with respect to 100 parts by mass of the binder resin. The above range is preferable because the dielectric constant and magnetic characteristics of the toner can be controlled in a more preferable range with a good balance.

[Binder resin for toner]
Examples of the binder resin used in the toner of the present invention include the following. Vinyl resin, styrene resin, styrene copolymer resin, polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, Silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin. Among these, styrene copolymer resins, polyester resins, hybrid resins in which a polyester resin and a vinyl resin are mixed, or partially reacted are used as resins preferably used.

Among these, as the binder resin for the toner used in the image forming method of the present invention, a polyester resin is preferable.
Moreover, in this invention, polyester-type resin represents resin in which 50 mass% or more in the structural component of resin is comprised by the polyester resin or the polyester site | part.
Further, a hybrid resin is more preferable as the binder resin for the toner. The hybrid resin is a resin having both properties as a polyester resin and properties as a vinyl resin. Therefore, various materials used for the toner can be uniformly dispersed regardless of the polarity or surface property. Therefore, it is preferable because the dielectric constant can be stably controlled.

  Examples of the polyester monomer used in the binder resin according to the present invention or the polyester monomer constituting the polyester unit of the hybrid resin include the following compounds.

  The following are mentioned as an alcohol component. 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, bisphenol A hydride, bisphenol derivatives represented by the following formula (9) and diols represented by the following formula (10).

  Examples of the acid component include the following. Benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or anhydrides thereof. Alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, or anhydrides thereof. Succinic acid or anhydride thereof substituted with an alkyl group or alkenyl group having 6 to 18 carbon atoms. Unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid and itaconic acid, or anhydrides thereof.

The polyester resin or the polyester unit according to the present invention is preferably a polyester resin having a crosslinked structure of a trivalent or higher polyvalent carboxylic acid or anhydride thereof and / or a trivalent or higher polyhydric alcohol.
Examples of the trivalent or higher polyvalent carboxylic acid or anhydride thereof include the following. 1,2,4-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, pyromellitic acid and acid anhydrides or lower alkyl esters thereof.
Examples of the trihydric or higher polyhydric alcohol include the following. 1,2,3-propanetriol, trimethylolpropane, hexanetriol, pentaerythritol.
In the binder resin of the present invention, an aromatic carboxylic acid having high stability due to environmental fluctuation is particularly preferred, and examples thereof include 1,2,4-benzenetricarboxylic acid and anhydrides thereof.

Examples of the vinyl monomer constituting the vinyl polymer unit of the vinyl resin or hybrid resin used in the binder resin according to the present invention include the following compounds.
Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl Styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene Styrene and its derivatives such as; styrene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; halogenation such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride Vinyls: Vinyl acetate, vinyl propionate, vinyl benzoate Vinyl esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, methacrylic acid Α-methylene aliphatic monocarboxylic acid esters such as phenyl, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-acrylate -Acrylic esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether Vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, etc. N-vinyl compounds of the following: vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide.

  Furthermore, the following are mentioned. Unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid and mesaconic acid; unsaturated such as maleic acid anhydride, citraconic acid anhydride, itaconic acid anhydride and alkenyl succinic acid anhydride 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, alkenyl succinic acid Half esters of unsaturated dibasic acids such as acid methyl half esters, methyl fumarate half esters, and methyl mesaconic acid half esters; unsaturated dibasic acid esters such as dimethyl maleic acid and dimethyl fumaric acid; acrylic acid and methacrylic acid Α, β-unsaturated acids such as crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic acid anhydride, anhydrides of the α, β-unsaturated acid and lower fatty acids Monomers having a carboxy group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.

  Furthermore, the following are mentioned. 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-methyl) (Hexyl) Monomers having a hydroxy group such as styrene.

  In the toner of the present invention, the vinyl resin or vinyl polymer unit used for the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. The following are mentioned as a crosslinking agent used in this case. Aromatic divinyl compounds (divinylbenzene, divinylnaphthalene); diacrylate compounds linked by alkyl chains (ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5- Pentanediol acrylate, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, and acrylates of the above compounds replaced with methacrylate); diacrylate compounds linked by an alkyl chain containing an ether bond (for example, , Diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 , Dipropylene glycol diacrylate, and acrylates of the above compounds replaced with methacrylate); diacrylate compounds entrapped with chains containing aromatic groups and ether bonds [polyoxyethylene (2) -2 , 2-bis (4hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4hydroxyphenyl) propane diacrylate, and acrylates of the above compounds replaced with methacrylate]; polyester type Diacrylate compounds (“MANDA” manufactured by Nippon Kayaku Co., Ltd.).

  The following are mentioned as a polyfunctional crosslinking agent. Pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds replaced with methacrylate; triallyl cyanurate, triallyl trimellitate .

These crosslinking agents are preferably used in an amount of 0.01 to 10.00 parts by mass, more preferably 0.03 to 5.00 parts by mass, with respect to 100 parts by mass of other monomer components. preferable.
Among these cross-linking agents, those which are preferably used in the binder resin from the viewpoint of fixability and offset resistance, are bonded with an aromatic divinyl compound (particularly divinylbenzene), a chain containing an aromatic group and an ether bond. Diacrylate compounds are mentioned.

  The following are mentioned as a polymerization initiator used for superposition | polymerization of the said vinyl-type resin or a vinyl-type polymer unit. 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2, 2'-azobis (2-methylbutyronitrile), dimethyl-2,2'-azobisisobutyrate, 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, Ketone peroxides such as acetylacetone peroxide and cyclohexanone peroxide, 2,2-bis (tert-butyl) Peroxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide , Α, α'-bis (tert-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide M-trioyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-2-e Xylethylperoxycarbonate, dimethoxyisopropylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, tert-butylperoxyacetate, tert-butylperoxyisobutyrate, tert-butyl peroxyneodecanoate, tert-butyl peroxy 2-ethylhexanoate, tert-butyl peroxylaurate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, di-tert-butyl Peroxyisophthalate, tert-butyl peroxyallyl carbonate, tert-amyl peroxy 2-ethylhexanoate, di-tert-butyl perper Carboxymethyl hexahydro terephthalate, di -tert- butyl peroxy azelate.

  In the present invention, when the above-described hybrid resin is used as the binder resin, it is preferable that a monomer component capable of reacting with both resin components is contained in the vinyl resin and / or the polyester resin component. Examples of monomers that can react with the vinyl resin among the monomers constituting the polyester resin component include unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof. Among the monomers constituting the vinyl resin component, those capable of reacting with the polyester resin component include those having a carboxy group or a hydroxy group, and acrylic acid or methacrylic acid esters.

  As a method for obtaining a reaction product of a vinyl resin and a polyester resin, in the presence of a polymer containing a monomer component capable of reacting with each of the vinyl resin and the polyester resin mentioned above, either or both of the resins are used. A method of carrying out a polymerization reaction is preferred.

  In addition, the above binder resin may be used alone, but two kinds of resins having different softening points, a high softening point resin (H) and a low softening point resin (L) are mixed in an arbitrary range. May be used. The high softening point resin (H) preferably has a softening point of 120 ° C. or higher and 170 ° C. or lower. The low softening point resin (L) preferably has a softening point of 70 ° C. or higher and lower than 120 ° C.

Such a system is preferable because the molecular weight distribution of the toner can be designed relatively easily and a wide fixing region can be provided.
When one kind of binder resin is used alone, the softening point Tm is preferably 95 ° C. or higher and 170 ° C. or lower, and more preferably 120 ° C. or higher and 160 ° C. or lower. If Tm is within the above range, the balance between high temperature offset resistance and low temperature fixability is good.
Moreover, it is preferable that the glass transition temperature (Tg) of binder resin is 45 degreeC or more from a viewpoint of storage stability. Further, from the viewpoint of low-temperature fixability, Tg is preferably 75 ° C. or less, and particularly preferably 65 ° C. or less.

[Release agent for toner]
In the present invention, a release agent (wax) can be used as necessary in order to impart releasability to the toner. As the wax, hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax are preferably used because of easy dispersion in toner particles and high releasability. If necessary, a small amount of one or two or more kinds of waxes may be used in combination. 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 ester wax; deacidified carnauba Deoxidized part or all of fatty acid esters such as wax. Furthermore, the following are mentioned. Saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as pracidic acid, eleostearic acid, and parinaric acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, Saturated alcohols such as sil alcohols; Long chain alkyl alcohols; Polyhydric alcohols such as sorbitol; Fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; Methylene bis stearic acid amide, ethylene biscapric acid amide , Saturated fatty acid bisamides such as ethylene bislauric acid amide and hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl adipine Amides, unsaturated fatty acid amides such as N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylene bis-stearic acid amide, N, N-distearyl isophthalic acid amide; calcium stearate, calcium laurate, Fatty acid metal salts such as zinc stearate and magnesium stearate (generally called metal soaps); waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid A partially esterified product of a fatty acid such as behenic acid monoglyceride and a polyhydric alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenation of a vegetable oil.

  Examples of waxes that are particularly preferably used in the present invention include aliphatic hydrocarbon waxes. Examples of such aliphatic hydrocarbon waxes include the following. A low molecular weight alkylene polymer obtained by radical polymerization of alkylene under high pressure or polymerization using a Ziegler catalyst under low pressure. An alkylene polymer obtained by thermally decomposing a high molecular weight alkylene polymer. A synthetic hydrocarbon wax obtained from a distillation residue of hydrocarbons obtained from a synthesis gas containing carbon monoxide and hydrogen by the age method, and a synthetic hydrocarbon wax obtained by hydrogenating it. Wax obtained by separating these aliphatic hydrocarbon waxes using the press sweating method, solvent method, vacuum distillation or fractional crystallization method.

Examples of the hydrocarbon as the matrix of the aliphatic hydrocarbon wax include the following. Carbonization synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often a multi-component system of two or more types) (for example, the Gintor method, Hydrocol method (using a fluidized catalyst bed)) Hydrogen compound). Hydrocarbons with up to several hundred carbon atoms obtained by the age method (using an identified catalyst bed) in which a large amount of waxy hydrocarbons can be obtained. Hydrocarbon obtained by polymerizing alkylene such as ethylene with Ziegler catalyst.
Among such hydrocarbons, in the present invention, it is preferable that the hydrocarbon is a linear hydrocarbon having a small number of branches and a long saturation, and particularly a hydrocarbon synthesized by a method not based on polymerization of alkylene has a molecular weight distribution. Is also preferable.

  Specific examples that can be used include the following. Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industry Co., Ltd.); High Wax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemical Corporation); Sazol H1, H2, C80, C105, C77 (Sazol); HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP-12 (Nippon Seiwa Co., Ltd.) )), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark) 350, 425, 550, 700 (Toyo Adress Co., Ltd.); wood wax, beeswax, rice wax, candelilla wax, Carnauba wax (Serarica NODA).

The timing of adding the release agent (wax) may be added at the time of melt-kneading during the production of toner particles, or may be at the time of production of a resin for toner, and is appropriately selected from existing methods. These release agents may be used alone or in combination.
The release agent is preferably added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the toner resin. When the amount is less than 1 part by mass, it is difficult to obtain the desired release effect. When the amount exceeds 20 parts by mass, the dispersion in the toner particles is poor, so that the toner adheres to the electrostatic image carrier, the developing member or the cleaning member. The surface of the member is likely to be contaminated, and the toner image is likely to deteriorate.

[Charge control agent for toner]
In the toner of the present invention, a charge control agent can be used to stabilize the triboelectric chargeability. Although the charge control agent varies depending on the type and physical properties of other toner particle constituent materials, generally, the toner particles are contained in an amount of 0.1 to 10.0 parts by mass per 100 parts by mass of the resin component. It is more preferable that 0.1 to 5.0 parts by mass is included.

  As such charge control agents, there are known ones for controlling the toner to be negatively charged and those for controlling the toner to be positively charged. One or two kinds of various kinds of charge control agents are used depending on the kind and use of the toner. The above can be used.

  Examples of toners that are negatively charged include the following. Organometallic complexes (monoazo metal complexes; acetylacetone metal complexes); metal complexes or metal salts of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids. In addition, examples of toners that are negatively charged include aromatic mono- and polycarboxylic acids and metal salts and anhydrides thereof; phenol derivatives such as esters and bisphenol. Among these, in particular, a metal complex or metal salt of an aromatic hydroxycarboxylic acid capable of obtaining stable charging performance is preferably used.

  Examples of controlling the toner to be positively charged include the following. Modified products with nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs thereof; onium salts such as phosphonium salts and These lake pigments: triphenylmethane dyes and these lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanic compound Etc.); metal salts of higher fatty acids. In the present invention, these can be used alone or in combination. Among them, charge control agents such as nigrosine compounds and quaternary ammonium salts are particularly preferably used for controlling the toner to be positively charged.

Specific examples include the following. Spiron Black TRH, T-77, T-95, TN-105 (Hodogaya Chemical Co., Ltd.); BONTRON (registered trademark) S-34, S-44, E-84, E-88 (Orient Chemical Industry ( TP-302, TP-415 (Hodogaya Chemical Co., Ltd.); BONTRON (registered trademark) N-01, N-04, N-07, P-51 (Orient Chemical Industry Co., Ltd.); Copy Blue PR (Clariant).
Moreover, charge control resin can also be used and can also be used together with the above-mentioned charge control agent.

[External additive for toner]
In the toner of the present invention, it is preferable to externally add fine silica powder to the toner particles in order to improve charging stability, developability, fluidity and durability.
The silica fine powder used in the present invention has good results when the specific surface area by the BET method by nitrogen adsorption is in the range of 30 m ² / g or more (particularly 50 m ² / g or more and 400 m ² / g or less). The silica fine powder is preferably used in an amount of 0.01 parts by weight or more and 8.00 parts by weight or less, more preferably 0.10 parts by weight or more and 5.00 parts by weight or less based on 100 parts by weight of the toner. The BET specific surface area of the silica fine powder can be calculated by adsorbing nitrogen gas on the surface of the silica fine powder and using the BET multipoint method. Examples of the specific surface area measuring apparatus include Autosorb 1 (manufactured by Yuasa Ionics), GEMINI 2360/2375 (manufactured by Micrometric), and Tristar 3000 (manufactured by Micrometric).

Moreover, it is preferable that the silica fine powder used for this invention is processed using various processing agents for the purpose of hydrophobization and triboelectric charge control as needed. The following are mentioned as a processing agent.
Unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane coupling agents, silane compounds having a functional group, or other organosilicon compounds.

Furthermore, you may add another external additive to the toner of this invention as needed. Examples of such external additives include charging aids, conductivity-imparting agents, fluidity-imparting agents, anti-caking agents, release agents at the time of heat roller fixing, lubricants, abrasives, etc. An inorganic fine powder is mentioned.
For example, examples of the lubricant include polyfluorinated ethylene powder, zinc stearate powder, and polyvinylidene fluoride powder.
Examples of the abrasive include cerium oxide powder, silicon carbide powder, and strontium titanate powder. Of these, strontium titanate powder is preferable.

[Toner manufacturing method]
The method for producing the toner particles of the present invention is not particularly limited, and for example, the following so-called pulverization method can be used. The pulverization method is a resin component and, if necessary, toner constituent materials such as a colorant and a release agent, which are uniformly mixed and then melt-kneaded, and the obtained kneaded product is cooled, pulverized, classified, and fluidity improved. This is a method of sufficiently mixing the material and the like using a mixer such as an FM mixer to obtain the developer of the present invention. As another method, toner particles can be produced by a so-called polymerization method such as an emulsion polymerization method or a suspension polymerization method.

  The following method can be used as a method for producing toner particles obtained through at least the melt-kneading step and the pulverizing step. The resin component and, if necessary, the wax, colorant, charge control agent, and other additives are sufficiently mixed by a mixer such as an FM mixer or a ball mill. The mixture is melt kneaded using a thermal kneader such as a twin-screw kneading extruder, a heating roll, a kneader, or an extruder. At that time, wax, magnetic iron oxide particles, and a metal-containing compound may be added. The melt-kneaded product is cooled and solidified, and then pulverized and classified to obtain toner particles.

Further, the toner particles and the external additive can be mixed by a mixer such as an FM mixer to obtain a toner.
The following are mentioned as a mixer. FM mixer (Nippon Coke Kogyo Co., Ltd.); Super mixer (manufactured by Kawata Co., Ltd.); Ribocorn (manufactured by Okawara Seisakusho Co., Ltd.); Pin mixer (manufactured by Taiheiyo Kiko Co., Ltd.); Redige mixer (manufactured by Matsubo Co., Ltd.). Examples of the kneader include the following. KRC Kneader (manufactured by Kurimoto Iron Works); Bus Co Kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works) PCM kneading machine (manufactured by Ikegai Co., Ltd.); triple roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho Co., Ltd.); kneedex (manufactured by Nihon Coke Industries Co., Ltd.); (Manufactured by Moriyama Seisakusho); Banbury mixer (manufactured by Kobe Steel). Examples of the pulverizer include the following. Counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron Corporation); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Industry Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); (Manufactured by Nisso Engineering Co., Ltd.); SK Jet O Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Nissin Engineering Co., Ltd.).

  Examples of the classifier include the following. Classy, Micron Classifier, Spedic Classifier (manufactured by Seishin Company); Turbo Classifier (manufactured by Nissin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Co., Ltd.) ); Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Industry Co., Ltd.); YM Microcut (manufactured by Yaskawa Shoji Co., Ltd.).

  Examples of the sieving apparatus used for sieving coarse particles include the following. Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (Tokuju Kosakusho Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Cleaner (manufactured by Freund Turbo); Micro shifter (manufactured by Kanno Sangyo Co., Ltd.); circular vibrating sieve.

FIG. 12 shows a schematic configuration of an example of an image forming apparatus to which the image forming method according to the present invention can be applied.
Developing means 101 contains magnetic toner 102. The bias applying unit 203 applies a voltage to the charging unit 200. The charging unit 200 charges the image carrier 103 which is a photoconductor. An electrostatic charge image is formed on the image carrier 103 by exposure light (for example, laser light or halogen lamp light) 105. The developing unit 101 includes a toner application blade (for example, an elastic blade, a magnetic blade, etc.) 108 and a developing sleeve 106. The developing sleeve 106 includes magnetic field generating means (for example, a magnet) 109.

  The electrostatic charge image is developed by the magnetic toner 102 accommodated in the developing means 101. As the developing method, a regular developing method or a reversal developing method is used. In the developing unit, an alternating bias, a pulse bias, and / or a direct current bias is applied to the developing sleeve 106 by the bias applying unit 201 as necessary. A voltage is applied to the transfer means (for example, transfer roller, transfer belt, etc.) 104 by the bias applying means 202. When the transfer material P is conveyed and reaches the transfer portion, the toner on the surface of the photoconductor 103 is charged by being charged from the back surface (the side opposite to the photoconductor 103 side) of the transfer material P by the transfer unit 104. The image is electrostatically transferred onto the transfer material P. If necessary, the toner image on the photosensitive member 103 is transferred to an intermediate transfer member (not shown) (for example, an intermediate transfer drum or an intermediate transfer belt), and the toner image is transferred from the intermediate transfer member to the transfer material P. May be.

  The toner image on the transfer material P separated from the photosensitive member 103 is heated and pressed by a pressing device (for example, a fixing device in which a pressure roller is pressed against a fixed heating element via a heat-resistant sheet, or a heating and pressure roller fixing device. Etc.) 204 and fixed to the transfer material P by heating. The toner remaining on the image carrier 103 after the transfer process is removed from the surface of the photoconductor 103 by a cleaning unit 107 (for example, a cleaning blade, a cleaning roller, and a cleaning brush) as necessary. For the image carrier 103 after cleaning, the process starting from the charging process by the charging unit 200 is repeated again.

  FIG. 13 is a schematic cross-sectional view of the process cartridge taken out from the image forming apparatus main body. The process cartridge is a cartridge in which the developing unit 101, the toner carrier (developing sleeve), that is, the developing unit 101, and the image carrier 103 are at least integrally formed. The process cartridge is formed so as to be detachable from the image forming apparatus main body (for example, a copying machine, a laser beam printer, etc.). 13 that are the same as those in FIG. 12 indicate the same members as those described with reference to FIG.

The image carrier used in the present invention has a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer, and the volume resistivity of the undercoat layer is It is preferably 1 × 10 ¹¹ or more and 1 × 10 ¹⁶ Ω · cm or less and contains an electron transporting compound.
At present, image carriers containing a charge generating substance are mainly used as image carriers used in process cartridges and electrophotographic apparatuses. The image carrier generally has a support and a photosensitive layer formed on the support. An undercoat layer may be provided between the support and the photosensitive layer for the purpose of suppressing charge injection from the support side to the photosensitive layer side and suppressing the occurrence of image defects such as black spots. Many.

In recent years, charge generation materials having higher sensitivity have been used. However, as the charge generating material becomes highly sensitive, the amount of generated charge increases, so that the charge tends to stay at the interface between the undercoat layer and the undercoat layer and the photosensitive layer. The phenomenon becomes remarkable.
In the image forming method using the charging member of the present invention, the image carrier has an undercoat layer having a volume resistivity of 1 × 10 ¹¹ or more and 1 × 10 ¹⁶ Ω · cm or less, and contains an electron transporting compound This is preferable because it is easy to suppress the occurrence of image defects such as black spots.

[Image carrier]
Hereinafter, an image carrier applicable to the present invention will be described.
The image carrier is preferably an image carrier having a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer.
The photosensitive layer is preferably a stacked type (functional separation type) photosensitive layer separated into a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. Furthermore, from the viewpoint of electrophotographic characteristics, the multilayer photosensitive layer is preferably a normal photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the support side.

[Support]
As the support, for example, a conductive support formed of a metal or alloy such as aluminum, nickel, copper, gold, or iron can be used. A support in which a thin film of aluminum, silver or gold metal is formed on an insulating support such as polyester resin, polycarbonate resin, polyimide resin or glass, or a support in which a thin film of conductive material such as indium oxide or tin oxide is formed. The body is mentioned.
The surface of the conductive support may be subjected to electrochemical treatment such as anodization, wet honing treatment, blast treatment, or cutting treatment in order to improve electrical characteristics and suppress interference fringes.

[Conductive layer]
A conductive layer may be provided between the conductive support and the undercoat layer. The conductive layer is a layer formed using a conductive layer coating liquid in which conductive particles are dispersed in a resin.
Examples of the conductive particles include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, silver, and metal such as conductive tin oxide and ITO (indium tin oxide). Oxide powder is mentioned.

Examples of the resin include polyester resin, polycarbonate resin, polyvinyl butyral, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.
Examples of the solvent for the conductive layer coating solution include ether solvents, alcohol solvents, ketone solvents, and aromatic hydrocarbon solvents. The thickness of the conductive layer is preferably 0.2 μm or more and 40 μm or less. It is more preferably 1 μm or more and 35 μm or less, and further preferably 5 μm or more and 35 μm or less.

[Undercoat layer]
The undercoat layer is provided on the support or the conductive layer described above.
The volume resistivity of the undercoat layer is preferably 1 × 10 ¹¹ Ω · cm or more and 1 × 10 ¹⁶ Ω · cm or less, and the undercoat layer preferably contains an electron transporting compound.
The electron transporting compound may contain a polymer of a composition having a polymerizable functional group and containing an electron transporting substance and a crosslinking agent, or a composition containing the electron transporting substance and a binder resin. It is more preferable in terms of enhancing the effect of the invention. The polymerizable functional group is any one of a hydroxy group, a thiol group, an amino group, and a carboxy group.

If the volume resistivity of the undercoat layer is within the above range, the binder resin may contain a small amount of an ionic substance, or the undercoat layer may further contain conductive particles. In that case, in order to make volume resistivity into the said range, content of an ionic substance and the kind of electroconductive particle can be selected suitably.
Examples of the conductive particles include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, and metal oxide powder such as conductive tin oxide and ITO. Can be mentioned.
The content of the electron transporting substance is more preferably 30% by mass or more and 70% by mass or less with respect to the total mass of the composition from the viewpoint of expression of the effects of the present invention.

[Electron transporting substances]
Examples of the electron transporting substance include quinone compounds, imide compounds, benzimidazole compounds, and cyclopentadienylidene compounds. The electron transporting material is preferably an electron transporting material having a polymerizable functional group. Examples of the polymerizable functional group include a hydroxy group, a thiol group, an amino group, a carboxy group, or a methoxy group. Below, the compound shown by either of following formula (A1)-(A11) is shown as a specific example of an electron transport substance.

In formulas (A1) to (A11), R ^{11 to} R ¹⁶ , R ^{21 to} R ³⁰ , R ^{31 to} R ³⁸ , R ^{41 to} R ⁴⁸ , R ^{51 to} R ⁶⁰ , R ^{61 to} R ⁶⁶ , R ^{71 to} R ^{78, R 81 ~R 90, R} 91 ~R 98, R 101 ~R 110, and ^R 111 ^{to R 120} each independently represents a monovalent group represented by the following formula (a), a hydrogen atom, a cyano group , A nitro group, a halogen atom, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic ring. One of the carbon atoms in the main chain of the alkyl group may be replaced with O, S, NH, or NR ¹²¹ (R ¹²¹ is an alkyl group). The substituent of the substituted alkyl group is an alkyl group, an aryl group, a halogen atom, or an alkoxycarbonyl group. The substituent of the substituted aryl group and the substituent of the substituted heterocyclic group are a halogen atom, a nitro group, a cyano group, an alkyl group, a halogen-substituted alkyl group, and an alkoxy group.
Z ²¹ , Z ³¹ , Z ⁴¹ and Z ⁵¹ each independently represent a carbon atom, a nitrogen atom or an oxygen atom. When Z ²¹ is an oxygen atom, R ²⁹ and R ³⁰ do not exist, and when Z ²¹ is a nitrogen atom, R ³⁰ does not exist. When Z ³¹ is an oxygen atom, R ³⁷ and R ³⁸ do not exist, and when Z ³¹ is a nitrogen atom, R ³⁸ does not exist. If Z ⁴¹ is an oxygen atom ^{R 47} and ^{R 48} is absent ^{when Z 41} is a nitrogen ^{atom, R 48} is absent. When Z ⁵¹ is an oxygen atom, R ⁵⁹ and R ⁶⁰ are not present, and when Z ⁵¹ is a nitrogen atom, R ⁶⁰ is not present.

In formula (A), at least one of α, β, and γ is a group having a substituent, and the substituent is selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxy group, and a methoxy group. At least one group. l and m are each independently 0 or 1, and the sum of l and m is 0 or more and 2 or less.

α is an alkylene group having 1-6 atoms in the main chain, an alkylene group having 1-6 atoms in the main chain substituted with an alkyl group having 1-6 carbon atoms, or a main chain substituted with a benzyl group. An alkylene group having 1 to 6 atoms, an alkylene group having 1 to 6 atoms in the main chain substituted with an alkoxycarbonyl group, or an alkylene group having 1 to 6 atoms in the main chain substituted with a phenyl group . At least one of R ^{11 to} R ¹⁶ , at least one of R ^{21 to} R ³⁰ , at least one of R ^{31 to} R ³⁸ , at least one of R ^{41 to} R ⁴⁸ , at least one of R ^{51 to} R ⁶⁰ , At least one of R ^{61 to} R ⁶⁶ , at least one of R ^{71 to} R ⁷⁸ , at least one of R ^{81 to} R ⁹⁰ , at least one of R ^{91 to} R ⁹⁸ , at least one of R ^{101 to} R ¹¹⁰ , At least one of R ^{111 to} R ¹²⁰ has a monovalent group represented by the formula (A). These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, and a carboxy group as a substituent. One of the carbon atoms in the main chain of the alkylene group may be replaced with O, S, NR ¹²² (wherein R ¹²² represents a hydrogen atom or an alkyl group).

  β represents a phenylene group, an alkyl-substituted phenylene group having 1 to 6 carbon atoms, a nitro-substituted phenylene group, a halogen-substituted phenylene group, or an alkoxy-substituted phenylene group. These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxy group, and a methoxy group as a substituent.

γ represents a hydrogen atom, an alkyl group having 1 to 6 atoms in the main chain, or an alkyl group having 1 to 6 atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms. These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxy group, and a methoxy group as a substituent. One of the carbon atoms in the main chain of the alkyl group may be replaced with O, S, or NR ¹²³ (wherein R ¹²³ represents a hydrogen atom or an alkyl group).

Among the electron transport materials represented by any one of the above formulas (A1) to (A11), at least one of R ^{11 to} R ¹⁶ , at least one of R ^{21 to} R ³⁰ , and at least one of R ^{31 to} R ^{38 one,} at least one of R 41 ^{to R 48,} at least one of R 51 ^{to R 60,} at least one of R 61 ^{to R 66,} at least one of R 71 ^{to R 78,} at least one of R 81 ^{to R 90} At least one of R ^{91 to} R ⁹⁸ , at least one of R ^{101 to} R ¹¹⁰ , and at least one of R ^{111 to} R ¹²⁰ are each an electron transporting substance having a monovalent group represented by the formula (A) Is more preferable.

  Specific examples of the electron transporting substance having a polymerizable functional group are shown below. In the table, Aa is represented by the same structural formula as A, and specific examples of the monovalent group are shown in the columns of A and Aa. In the table, when γ is “−”, it indicates a hydrogen atom, and the hydrogen atom of γ is included in the structure shown in the column of α or β.

t-Bu represents a tert-butyl group.

Derivatives having any structure of (A2) to (A6) and (A9) (derivatives of electron transporting materials) are Tokyo Chemical Industry Co., Ltd., Sigma Aldrich Japan Co., Ltd., and Johnson Matthey Japan Inc. It can be purchased from the company. The derivative having the structure of (A1) can be synthesized by reaction of naphthalene tetracarboxylic dianhydride, which can be purchased from Tokyo Chemical Industry Co., Ltd. or Johnson Matthey Japan Incorporated, and a monoamine derivative.
The derivative having the structure (A7) can be synthesized using a phenol derivative that can be purchased from Tokyo Chemical Industry Co., Ltd. or Sigma-Aldrich Japan Co., Ltd. as a raw material. The derivative having the structure of (A8) can be synthesized by reaction of perylenetetracarboxylic dianhydride that can be purchased from Tokyo Chemical Industry Co., Ltd. or Sigma Aldrich Japan Co., Ltd. and a monoamine derivative.
The derivative having the structure (A10) is obtained by oxidizing a phenol derivative having a hydrazone structure with an appropriate oxidizing agent such as potassium permanganate in an organic solvent using a known synthesis method described in Japanese Patent No. 3717320, for example. Can be synthesized. Derivatives having the structure of (A11) are naphthalenetetracarboxylic dianhydride, monoamine derivative and hydrazine, which can be purchased from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd. or Johnson Matthey Japan Incorporated. It can be synthesized by the reaction of

The compound represented by any of (A1) to (A11) has a polymerizable functional group (hydroxy group, thiol group, amino group, carboxy group, and methoxy group) that can be polymerized with a crosslinking agent. As a method for synthesizing a compound represented by any of (A1) to (A11) by introducing a polymerizable functional group into a derivative having any one of the structures (A1) to (A11), the following method is used. Is mentioned. For example, there is a method of directly introducing a polymerizable functional group after synthesizing a derivative having any one of the structures (A1) to (A11). There is also a method of introducing a structure having a polymerizable functional group or a functional group that can be a precursor of the polymerizable functional group. As a method to be described later, based on the halide of the derivative having any one of the structures (A1) to (A11), for example, a cross-coupling reaction using a palladium catalyst and a base is used to form an aryl group having a functional group. There is a way to introduce. Further, there is a method of introducing an alkyl group having a functional group using a cross-coupling reaction using a FeCl ₃ catalyst and a base based on a halide of a derivative having any one of the structures (A1) to (A11). is there. Also, there is a method of introducing a hydroxyalkyl group or a carboxy group by reacting an epoxy compound or CO ₂ after lithiation based on a halide of a derivative having any one of the structures (A1) to (A11). .
From the viewpoint of high solvent resistance and forming a strong cross-linked structure, the electron transporting material having a polymerizable functional group preferably has two or more polymerizable functional groups in the same molecule.

[Crosslinking agent]
Next, the crosslinking agent having a polymerizable functional group will be described.
As a crosslinking agent, the compound normally used as a crosslinking agent can be used. Specifically, the compounds described in Shinzo Yamashita and Tosuke Kaneko “Crosslinking Agent Handbook” published by Taiseisha (1981) and the like can be used.
The crosslinking agent used in the present invention is preferably an isocyanate compound or an amino compound.
The isocyanate compound used in the present invention preferably has 3 to 6 isocyanate groups or blocked isocyanate groups. For example, triisocyanatebenzene, triisocyanatemethylbenzene, triphenylmethane triisocyanate, lysine triisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate diphenylmethane diisocyanate, isophorone diisocyanate, xylylene diisocyanate, 2,2 , 4-trimethylhexamethylene diisocyanate, methyl-2,6-diisocyanatohexanoate, norbornane diisocyanate modified isocyanurate modified, biuret modified, allophanate modified, adduct modified with trimethylolpropane or pentaerythritol Various modified products such as
Of these, isocyanurate-modified products and adduct-modified products are more preferable.

  The blocked isocyanate group takes the form of -NHCOX (X is a protecting group). X may be any protecting group that can be introduced into an isocyanate group, but groups represented by the following (H1) to (H6) are more preferred.

  Specific examples of isocyanate compounds are shown in Tables 12-1 and 12-2 below.

  The undercoat layer of the present invention may further contain a thermoplastic resin having a polymerizable functional group. As the thermoplastic resin having a polymerizable functional group, a thermoplastic resin having a structural unit represented by the following formula (D) is preferable.

In formula (D), R ¹ represents a hydrogen atom or an alkyl group. Y ¹ represents a single bond, an alkylene group or a phenylene group. W ¹ represents a hydroxy group, a thiol group, an amino group, a carboxy group, or a methoxy group.
Examples of the thermoplastic resin having the structural unit represented by the formula (D) include an acetal resin, a polyolefin resin, a polyester resin, a polyether resin, and a polyamide resin. The structural unit represented by the above formula (D) may be included in the following characteristic structure, or may be included other than the characteristic structure. Characteristic structures are shown in (E-1) to (E-5) below. (E-1) is a structural unit of an acetal resin. (E-2) is a structural unit of polyolefin resin. (E-3) is a structural unit of a polyester resin. (E-4) is a structural unit of a polyether resin. (E-5) is a structural unit of polyamide resin.

In said formula, R < ²⁰¹ > -R < ²¹⁰ > shows a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group each independently. When R ²⁰¹ is C ₃ H ₈ (butyl group), it is represented as butyral.
A resin having a structural unit represented by formula (D) (hereinafter also referred to as resin D) can be obtained, for example, by the following method. A monomer having a polymerizable functional group (hydroxy group, thiol group, amino group, carboxy group, or methoxy group) that can be purchased from Sigma Aldrich Japan Co., Ltd. or Tokyo Chemical Industry Co., Ltd. is polymerized.

  The resin D can also be generally purchased. As a resin which can be purchased, the following are mentioned, for example. Polyether polyol resins such as AQD-457 and AQD-473 manufactured by Nippon Polyurethane Industry Co., Ltd., Sannics GP-400 and GP-700 manufactured by Sanyo Chemical Industry Co., Ltd., Phthalkid W2343 manufactured by Hitachi Chemical Co., Ltd., DIC Polyesters such as Watersol S-118, CD-520, Beccolite M-6402-50, M-6201-40IM, Halipip WH-1188 manufactured by Harima Kasei Co., Ltd., ES3604, ES6538 manufactured by Nippon Yupika Co., Ltd. Polyol resin, manufactured by DIC Corporation, polyacryl polyol resin such as Burnock WE-300, WE-304, polyvinyl alcohol resin such as Kuraray Kuraray Poval PVA-203, manufactured by Sekisui Chemical Co., Ltd. Polyvinyl acetal resins such as BX-1 and BM-1 Polyamide resins such as Nagase ChemteX Corporation's Toresin FS-350, Nippon Shokubai Co., Ltd. Aquaric, Lead City Co., Ltd. Finelex SG2000 and other carboxy group-containing resins, DIC Corporation's lactamide, etc. Polyamine resins, polythiol resins such as QE-340M manufactured by Toray Industries, Inc. Among these, polyvinyl acetal resins, polyester polyol resins and the like are more preferable from the viewpoints of polymerizability and uniformity of the electron transport layer.

The weight average molecular weight (Mw) of the resin D is more preferably in the range of 5000 to 400,000.
Examples of the quantitative method for the polymerizable functional group in the resin include the following. Carboxyl group titration with potassium hydroxide, amino group titration with sodium nitrite, hydroxyl group titration with acetic anhydride and potassium hydroxide, 5,5'-dithiobis (2-nitrobenzoic acid) used Titration of thiol groups. Moreover, the calibration curve method obtained from the IR spectrum of the sample which changed the polymeric functional group introduction ratio is mentioned.
Table 13 below shows specific examples of the resin D.

  The thickness of the undercoat layer is preferably from 0.3 μm to 15 μm, and more preferably from 0.5 μm to 5.0 μm.

(Charge generation layer)
A charge generation layer is formed on the photosensitive layer.
Examples of charge generating materials include azo pigments, perylene pigments, anthraquinone derivatives, anthanthrone derivatives, dibenzpyrenequinone derivatives, pyranthrone derivatives, violanthrone derivatives, isoviolanthrone derivatives, indigo derivatives, thioindigo derivatives, phthalocyanine pigments, and bisbenzimidazoles. Derivatives. Among these, azo pigments and phthalocyanine pigments are preferable. Among the phthalocyanine pigments, oxytitanium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine are preferable.

  Examples of the binder resin used for the charge generation layer include the following. Polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic ester, methacrylic ester, vinylidene fluoride, trifluoroethylene, polyvinyl alcohol resin, polyvinyl acetal resin, polycarbonate resin, polyester resin, polysulfone resin , Polyphenylene oxide resin, polyurethane resin, cellulose resin, phenol resin, melamine resin, silicon resin, epoxy resin. Among these, polyester resin, polycarbonate resin, and polyvinyl acetal resin are preferable, and polyvinyl acetal is more preferable.

The charge generation layer is preferably formed by forming a coating film of a coating solution for a charge generation layer obtained by dispersing a charge generation material together with a binder resin and a solvent, and drying the obtained coating film. The charge generation layer may be a vapor generation film of a charge generation material.
In the charge generation layer, the mass ratio of the charge generation material to the binder resin (charge generation material / binder resin) is preferably in the range of 10/1 to 1/10, and is preferably 5/1 to 1/5. A range is more preferable. Examples of the solvent used in the charge generation layer coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.
The thickness of the charge generation layer is preferably 0.05 μm or more and 5 μm or less.

(Hole transport layer)
A hole transport layer is formed on the charge generation layer.
Examples of the hole transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, benzidine compounds, triarylamine compounds, and triphenylamine. Alternatively, examples of the hole transport material include polymers having groups derived from these compounds in the main chain or side chain. Among these, a triarylamine compound, a benzidine compound, and a styryl compound are preferable.

  Examples of the binder resin used for the hole transport layer include polyester resins, polycarbonate resins, polymethacrylate resins, polyarylate resins, polysulfone resins, and polystyrene resins. Among these, polycarbonate resin and polyarylate resin are preferable. Moreover, as these molecular weights, weight average molecular weight (Mw) = 10,000-300,000 is preferable.

In the hole transport layer, the mass ratio of the hole transport material to the binder resin (hole transport material / binder resin) is preferably 10/5 to 5/10, and more preferably 10/8 to 6/10. .
The thickness of the hole transport layer is preferably 3 μm or more and 40 μm or less, and more preferably 5 μm or more and 16 μm or less. Examples of the solvent used in the hole transport layer coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

  A protective layer may be formed on the hole transport layer. The protective layer preferably contains conductive particles or a charge transport material and a binder resin. The protective layer may further contain an additive such as a lubricant. In addition, the binder resin itself may have conductivity and charge transport property, and in that case, the protective layer may not contain conductive particles or a charge transport material in addition to the binder resin. The binder resin of the protective layer may be a thermoplastic resin or a curable resin obtained by polymerization with heat, light, or radiation (electron beam). The thickness of the protective layer is preferably 1 μm or more and 10 μm or less.

As a method of forming each layer, a coating film obtained by dissolving and / or dispersing materials constituting each layer in a solvent is applied to form a coating film, and the resulting coating film is dried and / or cured. The method of forming by making it preferable is preferable. Examples of the method for applying the coating solution include a dip coating method (dip coating method), a spray coating method, a curtain coating method, and a spin coating method.
Next, it describes regarding the measuring method of each physical property which concerns on this invention.

<Calculation of luminance due to conductivity>
A method for evaluating the charging member based on the luminance due to the above-described conductivity will be described below.
FIG. 11 (11a) is a schematic view showing an embodiment of a scanning electron microscope for calculating the luminance due to the conductivity of the uneven portion.

  The power source 93 applies a positive potential to the conductive substrate 92. A predetermined potential is applied to the conductive substrate 92, and in this state, the electron beam 91 is irradiated from the surface of the charging member to each point on the surface with an acceleration voltage that enters only near the surface. The irradiation position of the electron beam 91 continuously scans the XY plane (Y is a direction perpendicular to the paper surface) in FIG. By irradiating the surface of the charging member with the electron beam 91, secondary electrons are emitted. The amount of measurement of the secondary electrons is converted into contrast information and imaged by associating it with the electron beam irradiation position to obtain a secondary electron image.

The amount of secondary electrons generated from the surface of the charging member by the electron beam irradiation at this time is as follows depending on the conductivity of the irradiated portion of the electron beam when a positive potential is applied to the conductive substrate 92 by the power source 93. [1] or [2] occurs.
[1] When the conductivity of the electron beam irradiation part is high (FIG. 11 (11c))
Secondary electrons generated by electron beam irradiation are attracted to the conductive substrate side having a positive potential, and the amount of secondary electrons detected by the detector is reduced.
[2] When the conductivity of the irradiated portion is low (FIG. 11 (11b))
The attraction of the secondary electrons to the side of the conductive substrate having a positive potential is suppressed, and the amount of secondary electrons detected by the detector is larger than in [1].

  From the above, the contrast converted from the magnitude of the measured amount of secondary electrons varies depending on the conductivity of the electron beam irradiation part, and the conductivity of the electron beam irradiation part can be estimated based on the brightness of the secondary electron image. It becomes. Specifically, as described above, the lower the luminance, the smaller the amount of secondary electrons detected by the detector, that is, the higher the conductivity of that part. The higher the luminance, the more secondary electrons are detected, that is, the lower the conductivity of the part.

In the present invention, using a scanning electron microscope capable of obtaining a contrast image due to the above conductivity,
The brightness K1 of the convex portion 18 of the bowl on the surface of the charging member in FIG.
Luminance K2 at the bottom of the bowl recess 17, and
The brightness K3 of the binder 12 exposed on the surface is calculated.
In order to obtain a contrast image due to the above conductivity, it is useful to apply a voltage to the object to be observed, and the scanning electron microscope is observed with a modified device that can be connected to a DC power supply via a vacuum feedthrough. It is preferable to carry out. “Vacuum feedthrough” refers to a vacuum attached to a vacuum wall that blocks the vacuum and the atmosphere to control the transport of electrical signals, physical movements, fluids, etc. to the inside of the device that maintains the vacuum. It is a part.

  Hereinafter, the observation conditions will be described. The positive potential applied to the conductive substrate needs to be in the range of 50 to 100V. This is because the voltage generally applied to the charging member during image formation is within the above range, and the contrast is correlated with the output image.

  The acceleration voltage of the electron beam needs to be 1 kV. When the acceleration voltage is lower than 1 kV, most of the electrons cannot pass through the bowl-shaped resin particles 11 shown in FIG. 2 (2a), including the above-described bowl-shaped resin particles and the binder portion located immediately below the bowl-shaped resin particles. The luminance K2 due to the conductivity cannot be calculated accurately. When the acceleration voltage of the electron beam is higher than 1 kV, most of the electrons are transmitted to the binder part immediately below the bowl-shaped resin particles, including the bowl-shaped resin particles and the binder part located immediately below the bowl-shaped resin particles. The value of the luminance K2 resulting from the conductivity cannot be calculated accurately.

  In accurately calculating the values of the luminances K1 to K3, the contrast and brightness of the scanning electron microscope have a great influence. Therefore, in order to accurately calculate the values of the luminances K1 to K3, in the present invention, the contrast is preferably 45% or more and 55% or less, the brightness is 25% or more and 30% or less, and the contrast is 50% and the brightness is 28%. It is more preferable.

Hereinafter, an example of specific conditions will be shown.
A scanning electron microscope (ULTRA plus, manufactured by Carl Zeiss) was remodeled so that a DC power supply (P4K-80H, manufactured by Matsusada Precision Co., Ltd.) could be connected via a vacuum feedthrough and observed. Observation is performed by applying a potential of 75 V to the conductive substrate, irradiating the surface of the charging member with an electron beam under the condition of an acceleration voltage of 1.0 kV, working distance (WD) 2.8 mm, magnification 2000 times, contrast 50%, Brightness was 28%. And the secondary electron image was obtained by observing the area | region which can observe both the recessed part derived from a bowl-shaped resin particle, and the binder of the surface of a charging member.

  In the secondary electron image, the luminance K1, luminance K2, and luminance K3 were calculated using image analysis software (ImageProPlus (registered trademark): manufactured by Adobe System). For each luminance, four average luminance values of all the pixels in the range of 10 μm × 10 μm were measured, and the average value of the average luminance values at these four locations was used.

<Measurement of surface roughness Rzjis and average unevenness Sm of charging member>
It measured according to the specification of JIS B 0601-1994 surface roughness, and measured using the surface roughness measuring device (brand name: SE-3500, Co., Ltd. product made from Kosaka Laboratory). Rzjis and Sm were measured at six randomly selected charging members and averaged. The cut-off value is 0.8 mm, and the evaluation length is 8 mm.

<Measurement of shape of bowl-shaped resin particles of charging member>
The measurement points are charged at each of five longitudinal points in the longitudinal direction of the charging member: the central part in the longitudinal direction, the position 45 mm away from the central part in the direction of both ends, and the position 90 mm away from the central part in the direction of both ends. A total of 10 locations including 2 locations (phase 0 ° and 180 °) in the circumferential direction of the member were used. At each of these measurement locations, the conductive resin layer is cut out using a focused ion beam processing observation apparatus (trade name: FB-2000C, manufactured by Hitachi, Ltd.) by 20 nm over 500 μm, and a cross-sectional image is taken. did. The obtained cross-sectional images were combined to calculate a three-dimensional image of bowl-shaped resin particles. From the stereoscopic image, a “maximum diameter” 55 as shown in FIG. 6 and a “minimum opening diameter” 63 as shown in FIG. 7 were calculated. Further, from the three-dimensional image, the “difference between the outer diameter and the inner diameter” of the bowl-shaped resin particles, that is, the “shell thickness” was calculated at any five points of the bowl-shaped resin particles. Such measurement is performed for 10 resin particles in the field of view, and the average value of the 100 measured values obtained is calculated, and these values are respectively calculated as “maximum diameter”, “minimum diameter of opening” and “shell”. Thickness ". When measuring the thickness of the shell, for each bowl-shaped resin particle, the thickness of the thickest part of the shell is not more than twice the thickness of the thinnest part, that is, the thickness of the shell is substantially uniform. It was confirmed that.

<Measurement of the height difference between the top of the convex portion on the surface of the charging member and the bottom of the concave portion>
The surface of the charging member was observed with a laser microscope (trade name: LXM5 PASCAL: manufactured by Carl Zeiss) in a visual field of 0.5 mm in length and 0.5 mm in width. Two-dimensional image data was obtained by scanning the laser in the XY plane within the field of view, and the focal point was moved in the Z direction, and the above scanning was repeated to obtain three-dimensional image data. As a result, first, it was confirmed that there were a concave portion derived from the opening of the bowl-shaped resin particles and a convex portion derived from the edge of the opening of the bowl-shaped resin particles. Further, the height difference 54 between the top of the convex portion and the bottom of the concave portion was calculated. Such an operation was performed on two bowl-shaped resin particles in the field of view. And the same measurement was performed about the longitudinal direction 50 places of the charging member, the average value of the obtained 100 resin particles was calculated, and this value was made into the "height difference".

<Measurement of electrical resistance of charging member>
FIG. 4 shows a measuring apparatus for measuring the electric resistance value of the charging member. A load was applied to both ends of the conductive substrate 33 by a bearing 32 to bring the charging member 34 into contact with a columnar metal 31 having the same curvature as that of the image carrier (not shown) so as to be parallel. In this state, the cylindrical metal 31 was rotated by a motor (not shown), and a DC voltage of −200 V was applied from the stabilized power supply 35 while the charging member 34 that was in contact was rotated. The current flowing at this time was measured with an ammeter 36, and the electric resistance value of the charging member 34 was calculated. Each load was 4.9 N, the diameter of the metal cylinder 31 was 30 mm, and the rotation of the metal cylinder 31 was a peripheral speed of 45 mm / second. In the measurement, the charging member 34 was allowed to stand for 24 hours or more in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and the measurement was performed using a measuring device placed in the environment.

<Measurement of volume average particle diameter of resin particles of charging member>
The volume average particle size of the resin particles of the charging member was measured by a Coulter LS-230 type particle size distribution meter (trade name, manufactured by Beckman Coulter, Inc.) which is a laser diffraction type particle size distribution meter. For the measurement, an aqueous module was used, and pure water was used as a measurement solvent. The measurement system of the particle size distribution meter was washed with pure water for about 5 minutes, and 10 mg to 25 mg of sodium sulfite was added to the measurement system as an antifoaming agent to execute the background function. Next, 3 to 4 drops of a surfactant was added to 50 mL of pure water, and 1 mg to 25 mg of a measurement sample was further added. The aqueous solution in which the sample was suspended was subjected to dispersion treatment for 1 to 3 minutes with an ultrasonic disperser to prepare a test sample solution. The test sample solution is gradually added to the measurement system of the measurement device, and the test in the measurement system is adjusted so that the PIDS (Polarization Intensity Differential Scattering) on the screen of the device is 45% or more and 55% or less. Measurement was performed by adjusting the sample concentration. The volume average particle diameter was calculated from the obtained volume distribution.

<Measurement method of saturation magnetization of toner>
The saturation magnetization (σs) of the toner of the present invention is measured with a vibrating magnetometer VSM P-1-10 (manufactured by Toei Kogyo Co., Ltd.) at a room temperature of 25 ° C. and an external magnetic field of 795.8 kA / m. To do. The reason why the external magnetic field is measured at 795.8 kA / m is that the relationship between the state of the developing sleeve-like spikes and the saturation magnetization of the toner appears most prominently.

<Measurement method of dielectric constant of toner>
About 1 g of the toner is weighed and a 20 kPa load is applied for 1 minute to form a disk-shaped measurement sample having a diameter of 25 mm and a thickness of 1.5 ± 0.5 mm.
This measurement sample is attached to ARES (manufactured by TA Instruments) equipped with a dielectric constant measurement jig (electrode) having a diameter of 25 mm. Using a 4284A Precision LCR meter (manufactured by Hewlett Packard) with a load of 120 g / cm ² at a measurement temperature of 40 ° C., the dielectric constant ε 'Is calculated.
The reason for measuring the dielectric constant in the present invention is that the frequency is 10 kHz and the temperature is 40 ° C. because the dielectric constant difference of the toner can be evaluated effectively and stably.

<Measuring method of average particle diameter (D1) and shape of primary particles of magnetic particles>
In the present invention, the average particle diameter (D1) and shape of the primary particles of the magnetic particles were measured and observed with a scanning electron microscope (JSM-6830F manufactured by JEOL). The average particle diameter (D1) of primary particles of magnetic particles is obtained by observing magnetic particles at a magnification of 30,000, measuring the particle diameter of 100 arbitrary magnetic particles, and calculating the average value of the measurement results of 100 particle diameters. The average particle diameter (D1) of the primary particles of the magnetic particles in the present invention was used.
When measuring the average particle diameter (D1) and shape of the primary particles of the magnetic particles in the toner, the toner, which is the specimen, is solidified with an epoxy resin, and then the flakes obtained by rounding the solidified product with a slicer such as a microtome are used. The toner particles were used for photography.

<Measurement method of height of convex part of magnetic particle>
The convex part of the magnetic particle described above is composed of one or more fine particles of iron-containing oxide. As shown in FIG. 14 described later, when the coated magnetic particles are observed with a TEM, the convex portions are observed with a size of about several nm.
Specifically, the size is 1 nm to 40 nm, particularly 7 nm to 20 nm. The size of the convex portion is the height protruding from the base surface of the coating layer when the coated magnetic particles are observed with a TEM. The convex portion may be present on the surface of the coating layer without any gap, or may be present so loosely that the base surface of the coating layer (that is, the reference surface on which the convex portion rises) is observed by TEM. Good.
The size of the protrusions is determined by TEM observation of the coated magnetic particles and targeting 15 or more protrusions as shown in FIG. 15 from the base surface 1503 of the covering layer 1502 covering the core particles 1501 to the apex of the protrusions 1504. The height h is measured, and the measured value is obtained by arithmetic averaging.

<Method for measuring presence or absence of convex portions of magnetic particles>
The presence or absence of a convex portion on the surface of the magnetic particle was observed with a transmission electron microscope (JEM-2100 manufactured by JEOL) and determined by whether or not there was a portion protruding with reference to the base surface of the planar portion of the octahedron.
When measuring the height of the protrusions on the surface of the magnetic particles in the toner, the toner particles are solidified with an epoxy resin and then the solidified product is sliced into pieces with a slicer such as a microtome. I took a photo.

<Analytical method of element of magnetic particle coating layer>
The ratio of the elements in the coating layer of the magnetic particles is obtained by suspending the magnetic particles of the present invention in 5% by mass dilute sulfuric acid at 50 ° C. . The concentration of silicon, aluminum and iron contained in the filtrate obtained by filtering this through a membrane filter is measured and determined by quantifying with an ICP emission spectroscopic analyzer. In this measurement, the amount of iron dissolved until silicon and aluminum are no longer detected is regarded as the amount of iron in the coating layer.

<Measurement Method of Softening Point Tm of Binder Resin for Toner>
The softening point Tm of the binder resin is measured as follows. The softening point of the resin is measured by using a constant load extrusion type capillary rheometer “Flow Characteristic Evaluation Device Flow Tester CFT-500D” (manufactured by Shimadzu Corporation) according to the manual attached to the device. In this device, while applying a constant load from the top of the measurement sample with the piston, the measurement sample filled in the cylinder is heated and melted, and the melted measurement sample is pushed out from the die at the bottom of the cylinder, and the piston drop amount at this time A flow curve showing the relationship between temperature and temperature can be obtained.

  In the present invention, the “melting temperature in the 1/2 method” described in the manual attached to the “flow characteristic evaluation apparatus Flow Tester CFT-500D” is the softening point. The melting temperature in the 1/2 method is calculated as follows. First, ½ of the difference between the piston lowering amount Smax at the time when the outflow ends and the piston lowering amount Smin at the time when the outflow starts is obtained (this is X. X = (Smax−Smin) / 2). And the temperature of the flow curve when the amount of piston descent in the flow curve is the sum of X and Smin is the melting temperature Tm in the 1/2 method.

As a measurement sample, about 1.0 g of a sample is compression-molded at about 10 MPa using a tablet molding compressor (for example, NT-100H, manufactured by NPA System) in an environment of 25 ° C. for about 60 seconds. A cylindrical shape having a diameter of about 8 mm is used.
The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rising start temperature: 50 ° C
Achieving temperature: 200 ° C
Measurement interval: 1.0 ° C
Temperature increase rate: 4.0 ° C./min Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 10.0 kgf (0.9807 MPa)
Preheating time: 300 seconds Die hole diameter: 1.0 mm
Die length: 1.0mm

<Method for Measuring Glass Transition Temperature (Tg) of Binder Resin for Toner>
The glass transition temperature (Tg) of the binder resin is measured at room temperature and normal humidity according to ASTM D3418-82 using a differential scanning calorimeter (DSC) and MDSC-2920 (manufactured by TA Instruments). As a measurement sample, a precisely weighed about 3 mg of binder resin is used. This is put in an aluminum pan and an empty aluminum pan is used as a reference. The measurement temperature range is 30 ° C. or more and 200 ° C. or less, once the temperature is increased from 30 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min, the temperature is decreased from 200 ° C. to 30 ° C. at a temperature decrease rate of 10 ° C./min The temperature is raised to 200 ° C. at a temperature rising rate of 10 ° C./min. In the DSC curve obtained in the second temperature raising process, the intersection point between the baseline intermediate line before and after the specific heat change and the differential heat curve is defined as the glass transition temperature Tg of the resin.

<Method for Measuring Toner Weight Average Particle Size (D4)>
The weight average particle diameter (D4) of the toner is calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method provided with a 100 μm aperture tube is used. For setting of measurement conditions and analysis of measurement data, 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, a 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 was set as follows.
On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter The value obtained using (made by Co., Ltd.) is set. 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 dedicated to Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.

(2) About 30 mL of the electrolytic solution is placed in a glass 100 mL flat bottom beaker. As a dispersant, “Contaminone N” (a nonionic surfactant, an anionic surfactant, a 10% by weight aqueous solution of a neutral detergent for washing a pH 7 precision measuring instrument comprising an organic builder, Wako Pure Chemical Industries, Ltd. About 0.3 mL of a diluted solution obtained by diluting (made in ()) with ion-exchanged water about 3 times by mass.

(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora150” (manufactured by Nikki Bios Co., Ltd.) with an electrical output of 120 W is prepared. . About 3.3 L of ion exchange 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 ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.

(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . 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 by the dedicated software is the weight average particle diameter (D4).

Hereinafter, the present invention will be described in more detail with reference to specific production examples and examples. In addition, all the parts and% of the following Examples and Comparative Examples are based on mass unless otherwise specified.
<Production Example of Charging Member Resin Particles (A-1)>
An aqueous mixed solution comprising 4000 parts by mass of ion-exchanged water, 9 parts by mass of colloidal silica as a dispersion stabilizer and 0.15 parts by mass of polyvinylpyrrolidone was prepared. Next, 50 parts by mass of acrylonitrile, 45 parts by mass of methacrylonitrile and 5 parts by mass of methyl methacrylate as a polymerizable monomer, 12.5 parts by mass of normal hexane as an inclusion substance, and dicumyl peroxide 0 as a polymerization initiator An oily mixture consisting of .75 parts by mass was prepared. This oily mixture was added to the aqueous mixture, and 0.4 parts by mass of sodium hydroxide was further added to prepare a dispersion.

  The obtained dispersion was stirred and mixed for 3 minutes using a homogenizer, charged into a nitrogen-substituted polymerization reaction vessel, and reacted at 60 ° C. for 20 hours with stirring at 400 rpm to prepare a reaction product. About the obtained reaction product, after repeating filtration and water washing, the resin particle was produced by drying at 80 degreeC for 5 hours. The resin particles were pulverized and classified by a sonic classifier to obtain charging member resin particles (A-1). Table 14 shows the physical properties of the resin particles for charging member (A-1).

<Production example of resin particles for charging member (A-2) to (A-4)>
The same method as in the production example of the resin particles for charging member (A-1) except that the amount of colloidal silica used, the type and amount of the polymerizable monomer, and one or more of the stirring rotation speed during polymerization were changed. Resin particles for the charging member (A-2) to (A-4) were obtained by preparing and classifying the resin particles. Table 14 shows the physical properties of the resin particles.

<Production Example of Conductive Rubber Composition (B-1) for Charging Member>
In a closed mixer adjusted to 50 ° C. by adding other materials shown in the column of component (1) in Table 15 to 100 parts by mass of acrylonitrile butadiene rubber (NBR) (trade name: N230SV, manufactured by JSR) Kneaded for 15 minutes. To this, the material shown in the column of component (2) in Table 15 was added. Subsequently, it knead | mixed for 10 minutes with the double roll machine cooled to the temperature of 25 degreeC, and the conductive rubber composition 1 was obtained. Table 16 shows the composition of the conductive rubber composition 1.

<Production Example of Conductive Rubber Composition (B-2) to (B-4) for Charging Member>
Except for changing the charging member resin particles (A-1) to charging member resin particles (A-2) to (A-4) shown in Table 16, the charging member conductive rubber composition (B-1). ) To obtain conductive rubber compositions (B-2) to (B-4) for charging members.

<Production example of charging member (C-1)>
[1. Conductive substrate
A thermosetting resin containing 10% by mass of carbon black was applied to a stainless steel substrate having a diameter of 6 mm and a length of 252.5 mm, and the dried one was used as a conductive substrate.

[2. Formation of conductive elastic layer]
Using an extrusion molding apparatus equipped with a cross head, the conductive rubber composition for charging member (B-1) produced in Production Example 21 was coated in a cylindrical shape on the peripheral surface with the conductive base as the central axis. . The thickness of the coated conductive rubber composition was adjusted to 1.75 mm.

  The extruded roller was vulcanized at 160 ° C. for 1 hour in a hot air oven, and then the end of the rubber layer was removed to make the length 224.2 mm, and a roller having a preliminary coating layer was produced. The outer peripheral surface of the obtained roller was polished using a plunge cut type cylindrical polishing machine. Pitrified grindstones were used as the abrasive grains, the abrasive grains were green silicon carbide (GC), and the particle size was 100 mesh. The rotational speed of the roller was 350 rpm, and the rotational speed of the grinding wheel was 2050 rpm. Polishing was performed by setting the cutting speed to 20 mm / min, and setting the spark-out time (time at the cutting 0 mm) to 0 seconds, to produce a conductive roller having a conductive elastic layer (coating layer). The thickness of the conductive elastic layer was adjusted to 1.5 mm. The crown amount of this roller (the average value of the difference between the outer diameter d1 at the center and the outer diameter d2 at positions 90 mm away from the center toward both ends) was 120 μm.

  After polishing, a charging member (C-1) was obtained by performing post-heating treatment at 180 ° C. for 1 hour in an air atmosphere using a hot stove. This charging member (C-1) had on its surface a conductive resin layer having a convex portion derived from the edge of the opening of the bowl-shaped resin particles and a concave portion derived from the opening of the bowl-shaped resin particles. . Tables 17 and 18 show the results of physical property measurement and image evaluation of the obtained charging member (C-1).

<Example of production of charging members (C-2) to (C-5)>
The charging members (C-2) to (C-5) are the same as the manufacturing example of the charging member (C-1) except that the vulcanization temperature and the heating temperature after polishing are changed to the conditions shown in Table 17. Was made. Tables 17 and 18 show the physical property measurement results of the charging members (C-2) to (C-5).

<Production example of charging member (C-6), (C-7)>
The charging member (C-1) except that the conductive rubber composition for charging member (B-1) was changed to the conductive rubber composition shown in Table 17 and the heating temperature after polishing was changed to the conditions shown in Table 17. ) To produce charging members (C-6) and (C-7) in the same manner as in the production example. Tables 17 and 18 show the physical property measurement results of the charging members (C-6) and (C-7).

<Production example of charging member (C-8), (C-9)>
Charging members (C-8) and (C-9) were produced in the same manner as in the production example of the charging member (C-1) except that the heating temperature after polishing was changed to 170 ° C or 220 ° C. . Tables 17 and 18 show the physical property measurement results of the charging member.

<Production example of charging member (C-10)>
The charging member (C-1) except that the conductive rubber composition for charging member (B-1) was changed to the conductive rubber composition for charging member (B-4) and the heating temperature after polishing was changed to 190 ° C. ) To produce a charging member (C-10). Tables 17 and 18 show the physical property measurement results of the charging member.

<Example of production of charging member (C-11)>
The conductive rubber composition for charging member (B-1) was changed to the conductive rubber composition for charging member (B-4), and the vulcanization temperature and the heating temperature after polishing were changed to the conditions shown in Table 17. Produced a charging member (C-11) in the same manner as in the production example of the charging member (C-1). Tables 17 and 18 show the physical property measurement results of the charging member (C-11).

<Example of production of charging member (C-12)>
About the process until grinding | polishing, it carried out similarly to the manufacture example of a charging member (C-1), and produced the grind | polished electroconductive roller. Next, graphite powder (UF-G5, manufactured by Showa Denko KK) was applied as conductive fine particles to the surface of the conductive roller using the current measuring device of FIG. Specifically, the polished conductive roller was brought into contact with each of the both ends so as to be parallel to the columnar metal 31 under a load of 4.9 N. In this state, the cylindrical metal 31 is rotated at a peripheral speed of 45 mm / second by a motor (not shown), and the non-woven fabric impregnated with the graphite powder is pushed into the cylindrical metal 31 and the driven rotating roller. It was applied by applying.

  In this state, only the outermost surface was re-polished by 10 μm to obtain a charging member (C-12) in which graphite powder was deposited only on the concave portions of the bowl-shaped resin particles. Tables 17 and 18 show the physical property measurement results of the charging member.

<Example of production of charging member (C-13)>
[Production example of resin particles]
-34.9 parts by mass of terephthalic acid-32.7 parts by mass of 1,4-butanediol-56.3 parts by mass of polyethylene glycol (number average molecular weight 2000)-0.1 parts by mass of tetrabutyl titanate-0.3 parts by antioxidant Mass part (trade name: Irganox 1010, manufactured by Ciba Geigy Co., Ltd.)
Was charged in an esterification reaction can and reacted at 220 ° C. for 2 hours in a nitrogen gas atmosphere.

  Next, after the reaction solution was transferred to a polymerization can, 0.1 part of tetrabutyl titanate was added, and polymerization was performed at 250 ° C. under a condition of 0.5 mmHg or less for 3 hours. After the polymerization was completed, the obtained polymer was discharged onto a cooling belt in a gut shape and pelletized to prepare a pellet-like polyether ester.

100 parts by mass of the polyether ester obtained above and 200 parts by mass of polyethylene oxide (manufactured by Meisei Chemical Industry Co., Ltd., trade name: R150) were dry blended with a tumbler mixer, and at 260 ° C. with a twin screw extruder. The mixture was kneaded with heating to obtain a mixture. The obtained mixture was cooled to about 150 ° C. and then mixed with 2000 parts by mass of water as a dispersion medium to obtain a suspension of polyether ester particles. This was subjected to centrifugal separation to separate the desired polyether ester resin particles, followed by drying by heating to obtain substantially spherical polyether ester resin particles having an average particle diameter of 10 μm. The volume resistivity of the obtained resin particles was 7.0 × 10 ⁸ Ω · cm.
The polyethylene oxide used here is incompatible with the polyether ester and is water-soluble. The polyether ester is insoluble in water.

[Preparation of conductive substrate]
A stainless steel shaft core (core metal) having a diameter of 6 mm and a length of 252.5 mm was used as a support. A thermosetting adhesive (trade name: METALOC U-20, manufactured by Toyo Chemical Laboratories) was applied to this and dried.
Next, the following materials were kneaded for 10 minutes in a closed mixer adjusted to 50 ° C. to prepare a raw material compound.
Epichlorohydrin rubber terpolymer 100 parts by mass (ethylene oxide (EO) / epichlorohydrin (EP) / allyl glycidyl ether (AGE) = (73 mol% / 23 mol% / 4 mol%))
-Calcium carbonate 60 parts by mass-Aliphatic polyester plasticizer 8 parts by mass-Zinc stearate 1 part by mass-Anti-aging agent 0.5 part by mass (2-mercaptobenzimidazole (MB))
・ Zinc oxide 2 parts by mass ・ Quaternary ammonium salt 2 parts by mass ・ Carbon black 5 parts by mass (average particle size: 100 nm, volume resistivity: 0.1 Ω · cm)

  Into this raw material compound, 1% by mass of sulfur (vulcanizing agent), 1% by mass of dibenzothiazyl sulfide (DM) (vulcanization accelerator) and 0.5% by mass with respect to the epichlorohydrin rubber terpolymer. Of tetramethylthiuram monosulfide (TS) was added. And it knead | mixed for 10 minutes with the double roll machine cooled to 20 degreeC, and obtained the compound for elastic layers.

  This elastic layer compound is extruded on an adhesive-coated support by an extrusion molding machine to form a roller shape having an outer diameter of about 9 mm, and then in an electric oven at 160 ° C. for 1 hour. Vulcanization and curing of the adhesive were performed. After cutting off both ends of the rubber to make the rubber length 228 mm, the surface was polished so as to form a roller shape having an outer diameter of 8.5 mm, and an elastic layer was formed on the support. At this time, the crown amount (difference in outer diameter at a position 90 mm away from the central portion and the central portion) was 120 μm.

[Preparation of conductive composite fine particles]
To 7.0 kg of silica particles (average particle diameter 15 nm, volume resistivity 1.8 × 10 ¹² Ω · cm) as metal oxide particles, 140 g of methyl hydrogen polysiloxane was added while the edge runner was running. The mixture was stirred for 30 minutes with a linear load of 588 N / cm (60 Kg / cm). The stirring speed at this time was 22 rpm.

Next, 7.0 kg of carbon black particles (average particle size 28 nm, volume resistivity 1.0 × 10 ² Ω · cm, pH = 6.5) was added over 10 minutes while the edge runner was operated. Furthermore, after mixing and stirring for 60 minutes at a linear load of 588 N / cm (60 kg / cm), carbon black was adhered to the methylhydrogenpolysiloxane coating, and then dried at 80 ° C. for 60 minutes using a dryer. Composite fine particles were obtained. The stirring speed at this time was 22 rpm. The obtained conductive composite fine particles had an average particle size of 15 nm and a volume resistivity of 2.3 × 10 ² Ω · cm.

[Production of titanium oxide particles]
1000 g of acicular rutile type titanium oxide particles (average particle size 15 nm, length: width = 3: 1), volume resistivity 5.2 × 10 ¹⁰ Ω · cm), 110 g of isobutyltrimethoxysilane as a surface treatment agent, toluene as a solvent A slurry was prepared by blending 3000 g. This slurry was mixed with a stirrer for 30 minutes, and then supplied to Viscomill in which 80% of the effective internal volume was filled with glass beads having an average particle diameter of 0.8 mm, and wet crushing was performed at a temperature of 35 ± 5 ° C. .

  The slurry obtained by the wet pulverization treatment was subjected to distillation under reduced pressure (bath temperature: 110 ° C., product temperature: 30 to 60 ° C., degree of vacuum: about 100 Torr) using a kneader, and surfaced at 120 ° C. for 2 hours. The treating agent was baked. The particles after baking were cooled to room temperature and then pulverized using a pin mill.

[Preparation of paint for surface layer formation]
Methyl isobutyl ketone was added to a caprolactone-modified acrylic polyol solution (trade name: Plaxel DC2016, manufactured by Daicel Chemical Industries, Ltd.) to adjust the solid content to 17% by mass. The following materials were added to 411.8 parts by mass of this solution (100 parts by mass of the solid content of the acrylic polyol solution) to prepare a mixed solution.
-50 parts by mass of the above-mentioned composite conductive fine particles-30 parts by mass of the above titanium oxide particles-0.24 parts by mass of modified dimethyl silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Silicone Co., Ltd.)
56 parts by mass of a 7: 3 mixture of each butanone oxime block of hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI)

  At this time, the mixture of the block HDI and the block IPDI was added so that “NCO / OH = 1.0”. For HDI and IPDI, HDI (trade name: Duranate TPA-B80E, manufactured by Asahi Kasei Chemicals Corporation) and IPDI (trade name: Bestanat B1370, manufactured by Degussa) were used.

  In a 450 mL glass bottle, 200 parts by mass of a total of 548.04 parts by mass of the above mixed solution and 200 parts by mass of glass beads having an average particle size of 0.8 mm as media were mixed and dispersed for 72 hours using a paint shaker disperser. . After dispersion, 2.72 parts by mass of the resin particles (corresponding to 10 parts by mass with respect to 100 parts by mass of the solid content of the acrylic polyol solution) is added, and then dispersed for another 30 minutes, and then the glass beads are separated by filtration. Thus, a paint for forming the surface layer was obtained.

  This surface layer-forming coating material was dipped on the conductive substrate once, air-dried at room temperature for 30 minutes or more, then dried in a hot air circulating dryer set at 80 ° C. for 1 hour, and further set at 160 ° C. It dried for 1 hour with the hot air circulation dryer, and formed the surface layer on the electroconductive base | substrate. The dipping coating dipping time is 9 seconds, the dipping coating lifting speed is adjusted so that the initial speed is 20 mm / second and the final speed is 2 mm / second, and between 20 mm / second and 2 mm / second is linear with respect to time. The speed was changed.

Thus, a charging member (C-13) having a convex portion derived from the resin particles on the surface layer on the conductive substrate was produced.
The charging member (C-13) obtained had a ten-point average roughness (Rzjis) of 7.0 (μm) on the surface and a volume low efficiency of the surface layer of 7.0 × 10 ⁸ .

<Example of production of charging member (C-14)>
In the production example of the charging member (C-13), a charging member (C-14) was produced in the same manner as the charging member (C-13) except that the resin particles were not added. The ten-point average roughness (Rzjis) on the surface of the obtained charging member (C-14) was 2.1 μm.

<Example of production of image carrier (D-1)>
An aluminum cylinder (JIS-A3003) having a diameter of 30 mm was used as the conductive support.
Next, a conductive layer was formed on the support.
For the conductive layer, the following materials were placed in a sand mill using 450 parts of glass beads having a diameter of 0.8 mm, and dispersed under the conditions of a rotation speed of 2000 rpm, a dispersion treatment time of 4.5 hours, and a cooling water set temperature of 18 ° C. Treatment was performed to obtain a dispersion.
Titanium oxide (TiO ₂ ) particles coated with oxygen-deficient tin oxide (SnO ₂ ) as metal oxide particles 214 parts Phenol resin (Brand name: Priorofen J-325) 132 parts Methanol 40 1-methoxy-2-propanol 58 parts

Glass beads were removed from this dispersion with a mesh (aperture: 150 μm). After removing the glass beads, silicone resin particles as a surface-roughening agent (Tospearl 120, manufactured by Momentive Co., Ltd.) are used so as to be 10% by mass with respect to the total mass of the metal oxide particles and the binder resin in the dispersion. ) Was added to the dispersion. Further, a silicone oil (SH28PA, manufactured by Toray Dow Corning Co., Ltd.) as a leveling agent was dispersed in the dispersion so that the total mass of the metal oxide particles and the binder resin in the dispersion was 0.01% by mass. Added to. A conductive layer coating solution was prepared by stirring the dispersion.
The conductive layer coating solution was dip-coated on a support, and the resulting coating film was dried and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 30.2 μm.

Next, an undercoat layer was formed on the conductive layer.
First, the following materials were mixed in 25.0 parts of methanol (made by Kishida Chemical Co., Ltd., special grade) and 6.5 parts of n-butanol (made by Kishida Chemical Co., Ltd., special grade), and dissolved by stirring. The undercoat layer coating solution was prepared.
3.0 parts of an electron transporting compound represented by the following formula (11) Copolymer nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) as a binder resin
3.5 parts Undercoat layer coating solution is dip-coated on the conductive layer to form a coating film, and the resulting coating film is dried for 20 minutes at a temperature of 120 ° C. A layer was formed.

Next, a charge generation layer was formed on the undercoat layer.
First, the following materials are put into a sand mill using glass beads having a diameter of 0.8 mm, and dispersion treatment is performed under the condition of dispersion treatment time: 3 hours. Next, 250 parts of ethyl acetate is added, thereby generating a charge generation layer. A coating solution was prepared.
Strong peaks at 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction Crystal part of hydroxygallium phthalocyanine crystal (charge generating substance) 10 parts Polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5 parts Cyclohexanone 250 parts A charge generation layer having a film thickness of 0.15 μm was formed by dip-coating the film and drying the obtained coating film at 100 ° C. for 10 minutes.

Next, a hole transport layer was formed on the charge generation layer.
First, a hole transport layer coating solution was prepared by dissolving the following materials in a mixed solvent of 50 parts of dimethoxymethane and 50 parts of o-xylene.
Compound represented by the following formula (12-1) 4 parts Compound represented by the following formula (12-2) 4 parts Bisphenol Z-type polycarbonate (trade name: Z400, manufactured by Mitsubishi Engineering Plastics) 10 parts The hole transport layer coating solution is dip-coated on the charge generation layer to form a coating film, and the resulting coating film is dried at a temperature of 120 ° C. for 40 minutes to form a hole transport layer having a thickness of 15 μm. Formed.

  In this way, an image carrier in which a conductive support, a conductive layer, an undercoat layer, a charge generation layer, and a hole transport layer were laminated in this order was produced. Further, in the same manner as described above, the volume resistivity of the undercoat layer was measured by the method described above in a state where the conductive support, the conductive layer, and the undercoat layer were laminated in this order. The measurement results are shown in Table 23.

<Example of production of image carrier (D-2)>
In the production of the image carrier (D-1), it was produced in the same manner as the image carrier (D-1) except that the production of the undercoat layer was changed as follows.
4.0 parts of an electron transport compound shown in (A-117),
5.5 parts of a crosslinking agent represented by the formula (B1: protecting group H1),
Resin represented by formula (D25) 0.5 part The above material is dissolved in a mixed solvent of 50 parts of THF (tetrahydrofuran) and 50 parts of 1-methoxy-2-propanol, and stirred to obtain an undercoat layer coating solution. Prepared.

The undercoat layer coating solution is applied onto the conductive layer by dip coating, and the resulting coating film is heated at 160 ° C. for 40 minutes to evaporate the solvent and harden it, thereby reducing the film thickness to 0.7 μm. A layer was formed.
In the state where the conductive support, the conductive layer, and the undercoat layer were laminated in this order, the volume resistivity of the undercoat layer was measured by the method described above. The measurement results are shown in Table 23.

<Example of production of image carrier (D-3)>
In the production of the image carrier (D-1), it was produced in the same manner as the image carrier (D-1) except that the production of the undercoat layer was changed as follows.
4.0 parts of an electron transporting compound represented by the formula (A-107),
5.5 parts of crosslinking agent represented by formula (B1: protecting group H1) The above materials were dissolved in a mixed solvent of 50 parts of THF and 50 parts of 1-methoxy-2-propanol. Further, 9.0 parts of titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) and 25 parts of glass beads having a diameter of 0.8 mm were added to obtain a mixed solution. This mixed solution was subjected to a dispersion treatment for 16 hours with a paint shaker, and glass beads were removed to obtain an undercoat layer coating solution.

This undercoat layer coating solution is applied onto the conductive layer by dip coating, and the resulting coating film is heated at 160 ° C. for 40 minutes to evaporate the solvent and harden it, thereby undercoating the film thickness to 1.4 μm. A layer was formed.
In the state where the conductive support, the conductive layer, and the undercoat layer were laminated in this order, the volume resistivity of the undercoat layer was measured by the method described above. The measurement results are shown in Table 23.

<Example of production of image carrier (D-4)>
In the production of the image carrier (D-1), it was produced in the same manner as the image carrier (D-1) except that the production of the undercoat layer was changed as follows.
3.0 parts of an electron transporting compound represented by the above formula (11),
N-methoxymethylated nylon (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Co., Ltd. (former Teikoku Chemical Industry Co., Ltd.)) 4.5 parts of the above resin as methanol (Kishida Chemical Co., Ltd.) ), Special grade) 25.0 parts, and n-butanol (made by Kishida Chemical Co., Ltd., special grade) 6.5 parts. Further, 5.0 parts of titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) and 25 parts of glass beads having a diameter of 0.8 mm were added to obtain a mixed solution. This mixed solution was subjected to a dispersion treatment for 16 hours with a paint shaker, and glass beads were removed to obtain an undercoat layer coating solution.

The undercoat layer coating solution was applied onto the conductive layer by dip coating, and the resulting coating film was heated at 100 ° C. for 40 minutes to evaporate the solvent, thereby forming an undercoat layer having a thickness of 1.3 μm.
In the state where the conductive support, the conductive layer, and the undercoat layer were laminated in this order, the volume resistivity of the undercoat layer was measured by the method described above. The measurement results are shown in Table 23.

<Example of production of binder resin for toner (F-1)>
-Bisfer A ethylene oxide adduct (2.0 mol addition) 50.0 mol parts-Bisfer A propylene oxide adduct (2.3 mol addition) 50.0 mol parts-Terephthalic acid 60.0 mol parts-Trimellitic anhydride 20. 0 mol part / acrylic acid 10.0 mol part 70 parts by mass of the above polyester monomer mixture was charged into a four-necked flask and equipped with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device, under a nitrogen atmosphere. And stir at 160 ° C. A mixture of 30 parts by mass of a vinyl polymerization monomer (styrene: 90.0 mol parts, butyl acrylate: 10.0 mol parts) constituting the vinyl polymer portion and 2.0 mol parts of benzoyl peroxide as a polymerization initiator. It dropped over 4 hours from the dropping funnel. Then, after reacting at 160 ° C. for 5 hours, the temperature was raised to 230 ° C., 0.05% by mass of tetraisobutyl titanate was added, and the reaction time was adjusted so as to obtain a desired viscosity.
After completion of the reaction, it was taken out from the container, cooled and pulverized to obtain a toner resin (F-1) which is a hybrid resin. Table 19 shows properties of the obtained resin (F-1).

<Example of production of binder resin for toner (F-2)>
A toner binder resin (F-2) was obtained in the same manner as in the production example of the toner binder resin (F-1) except that the monomers listed in Table 19 were used. Table 19 shows properties of the obtained binder resin for toner (F-2).

<Production example of binder resin for toner (F-3), (F-4)>
The monomers listed in Table 19 were charged in a 5-liter autoclave together with 0.05 mass% of tetraisobutyl titanate with respect to the total amount of monomers, and a reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirring device were attached. . And polycondensation reaction was performed at 230 degreeC, introduce | transducing nitrogen gas in an autoclave. The reaction time was adjusted to achieve the desired softening point. After completion of the reaction, it was taken out from the container, cooled and pulverized to obtain toner resins (F-3) and (F-4). Table 19 shows properties of the obtained toner resins (F-3) and (F-4).

<Example of production of binder resin for toner (F-5)>
Into a four-necked flask, 250 parts by mass of degassed water and 50 parts by mass of a 1% by weight aqueous solution of polyvinyl alcohol were added, and then 83 parts by mass of styrene, 17 parts by mass of n-butyl acrylate, and 0.001 part by mass of divinylbenzene. Then, a mixed solution of 0.1 part by mass of 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane was added and stirred to obtain a suspension.

After the inside of the four-necked flask was placed in a nitrogen atmosphere, the temperature was raised to 85 ° C. to initiate polymerization. After maintaining at the same temperature for 20 hours, 0.1 part by mass of benzoyl peroxide was further added, and further maintained for 8 hours to complete the polymerization. Next, the polymer particles were separated by filtration, sufficiently washed with water and dried to obtain a binder resin for toner (F-5).
The binder resin for toner (F-5) had a Tg of 61.2 ° C. and a softening point of 143.5 ° C.

<Example of production of binder resin for toner (F-6)>
Into a four-necked flask, 300 parts by mass of xylene was added, and the inside of the container was sufficiently replaced with nitrogen while stirring, and then heated to reflux.
Under this reflux, a mixed solution of 83 parts by mass of styrene, 17 parts by mass of acrylic acid-n-butyl and 2 parts by mass of di-tert-butyl peroxide was dropped over 4 hours, and the polymerization was carried out by maintaining for 2 hours. Upon completion, a low molecular weight polymer solution was obtained. This polymer solution was dried under reduced pressure to obtain a binder resin for toner (F-6).
The binder resin for toner (F-6) had a Tg of 60.0 ° C. and a softening point of 97.3 ° C.

<Example of production of magnetic particles (G-1) for toner>
(1) Production of Core Particles 92 L of an aqueous ferrous sulfate solution having an Fe ²⁺ concentration of 1.79 mo1 / L and 88 L of an aqueous sodium hydroxide solution of 3.74 N were added and mixed and stirred. The pH of this solution was 6.5.
While maintaining this solution at a temperature of 89 ° C. and a pH of 9 to 12, air of 20 L / min was blown to cause an oxidation reaction to generate core particles. When ferrous hydroxide was completely consumed, air blowing was stopped and the oxidation reaction was terminated. The obtained magnetite core particles had an octahedral shape.

(2) Formation of coating layer 5 L of aqueous solution obtained by mixing 2 L of 0.7 mo1 / L sodium silicate aqueous solution and 2 L of 0.9 mo1 / L ferrous sulfate aqueous solution into the slurry after reaction containing 13500 g of core particles It was added while maintaining pH 8-9. Thereafter, air of 10 L / min was blown until Fe 2+ in the slurry no longer remained.

  Subsequently, 5 L of an aqueous solution obtained by mixing 2 L of a 1.5 mo1 / L aluminum sulfate aqueous solution and 2 L of a 0.9 mo1 / L ferrous sulfate aqueous solution is added to the post-reaction slurry containing core particles while maintaining pH 8-9. did. Thereafter, air of 10 L / min was blown until Fe 2+ in the slurry no longer remained. The temperature of the slurry was maintained at 89 ° C. After mixing and stirring for 30 minutes, the slurry was filtered, washed and dried to obtain the intended magnetic particles for toner (G-1). With respect to the magnetic particles for toner (G-1), as a result of observing the method for measuring the presence or absence of the convex portions of the magnetic particles by the above method, convex portions 1401 were observed on the surface as shown in FIG. In addition, Table 20 shows properties of the magnetic particle for toner (G-1).

<Production Example of Toner Magnetic Particles (G-2) (G-3)>
In the production example of the magnetic particle for toner (G-1), except that the production conditions were changed as shown in Table 20, the magnetic particle for toner was produced in the same manner as in the production method of the magnetic particle for toner (G-1). (G-2) and (G-3) were obtained. Table 20 shows properties of the magnetic particles for toner (G-2) and (G-3).

<Production Example of Toner (H-1)>


-Toner binder resin (F-1) 55 parts by mass-Toner binder resin (F-4) 45 parts by mass-Magnetic particles (G-1) 60 parts by mass-Release agent Fischer Tropus wax (Sazol) Manufactured, C105, melting point 105 ° C.) 2 parts by mass / charge control agent (T-77: manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by mass The above materials were premixed with an FM mixer (manufactured by Nippon Coke Industries, Ltd.). Thereafter, the mixture was melt-kneaded by a biaxial kneading extruder (PCM-30 type, manufactured by Ikegai Co., Ltd.).

The obtained kneaded product was cooled, coarsely pulverized with a hammer mill, and then pulverized with a mechanical pulverizer (T-250 manufactured by Freund Turbo). The finely pulverized powder thus obtained was classified using a multi-division classifier utilizing the Coanda effect to obtain negatively chargeable toner particles having a weight average particle diameter (D4) of 7.0 μm.
Next, with respect to 100 parts by mass of the toner particles, 1.0 part by mass of hydrophobic silica fine powder [BET specific surface area 200 m ² / g, silica fine powder is hydrophobized with dimethyl silicone oil] and strontium titanate. 0.2 parts by mass of fine powder was externally added and sieved with a mesh having an opening of 100 μm to obtain toner (H-1). Table 21 shows properties of Toner (H-1).

<Production Examples of Toners (H-2) to (H-17)>
Toners (H-2) to (H-17) were obtained in the same manner as in the production example of the toner (H-1) except that the formulation shown in Table 21 was used. Table 21 shows properties of the obtained toners (H-2) to (H-17).

<Example 1>
The machine used for evaluation in this example was modified as follows with respect to a commercially available magnetic one-component printer HP LaserJet Enterprise 600 M603dn (manufactured by Hewlett-Packard: process speed 350 mm / sec) and cartridge CE390X.
-Change the process speed to 400 mm / second-Change the charging member to the charging member (C-1)-Change the image carrier to (D-2) With this evaluation machine, the printing rate is 2% under the following environments: An endurance test of 50000 sheets was performed intermittently for each horizontal line image (the rotation of the printer was stopped for 3 seconds each time one sheet was printed).
In a low temperature and low humidity environment (temperature 15 ° C., relative humidity 10%),
In a normal temperature and humidity environment (temperature 23 ° C., relative humidity 60%),
Under a high temperature and high humidity environment (temperature 32.5 ° C., relative humidity 80%).

[Vertical stripe image]
In a low-temperature and low-humidity environment, a halftone image was output at the end of 50000 sheets, and the occurrence state of a vertical streak-like image caused by uneven wear of the image carrier was evaluated from the image.
The evaluation criteria are as follows.
A: Not generated B: Only slight generation C: Generation is observed in a part of the image, but there is no problem in practical use. D: Image quality deteriorates due to generation.

[Halftone density unevenness]
Under all evaluation environments, a halftone image was output at the end of 50000 sheets, and the occurrence state of halftone density unevenness was evaluated from the image. The evaluation criteria are as follows.
A: Halftone density unevenness is hardly visible.
B: Halftone density unevenness is slightly visible but difficult to understand.
C: A level at which halftone density unevenness is visible but is not a concern.
D: Halftone density unevenness is clearly visible.
The results are shown in Table 22.

[Evaluation of point-like images]
In a low-temperature and low-humidity environment, a halftone image was output at the end of 50,000 sheets, and the occurrence state of a spot-like image was evaluated. The evaluation criteria are as follows: A: No spot-like image defect is observed.
B: Only slight spot-like image defects are observed.
C: It is recognized that a spot-like image defect occurs in a part of the region corresponding to the rotation pitch of the charging roller, but there is no practical problem.
D: A spot-like image defect is recognized in a wide range and is conspicuous.
The results are shown in Table 22.

[Evaluation of horizontal stripe image]
In a low-temperature and low-humidity environment, a halftone image was output at the end of 50,000 sheets, and the state of occurrence of a horizontal streak-like image caused by charging was evaluated. The evaluation criteria are as follows: A: No horizontal streak-like image defect is observed.
B: Only a few horizontal streak-like image defects are observed.
C: Although horizontal streak-like image defects are observed in some areas corresponding to the rotation pitch of the charging roller, there is no practical problem.
D: A horizontal streak-like image defect is recognized in a wide range and is conspicuous.
The results are shown in Table 22.

<Examples 2 to 12>
Evaluations similar to those in Example 1 were performed using the combinations shown in Table 22. The results are shown in Table 22.
<Comparative Examples 1-5>
Evaluations similar to those in Example 1 were performed using the combinations shown in Table 22. The results are shown in Table 22.

As shown in Table 18, the charging members C-1 to C-7 satisfy the following mathematical formulas (1) to (3).
Formula (1) K2 <K1
Formula (2) K3 <K1
Formula (3) 0.8 ≦ K2 / K3 ≦ 1.2

As shown in Table 21,
Toners H-1 to H-14 are
The saturation magnetization is 15.0 Am ² / kg or more and 35.0 Am ² / kg or less at a magnetic field of 795.8 kA / m, and the dielectric constant ε ′ is 25.0 pF / m or more and 40 at a frequency of 10 kHz and a temperature of 40 ° C. 0.0 pF / m or less.
The toners H-1 to H-10 and H-13 to H-14 contain 30 to 70 parts by mass of magnetic particles with respect to 100 parts by mass of the binder resin.

As shown in Table 23, in the image carriers D-1 to D-3, the volume resistivity of the undercoat layer is 1 × 10 ¹¹ Ω · cm or more and 1 × 10 ¹⁶ Ω · cm or less.

DESCRIPTION OF SYMBOLS 1 Conductive base | substrate, 2 Conductive resin layer 11 Bowl-shaped resin particle, 12 Conductive resin layer (binder),
13 lining layers, 14 conductive resin layers (surface layers),
15 image carrier, 16 conductive fine particles, 17 concave portions, 18 convex portions,
21 conductive resin layer (intermediate layer), 22 conductive resin layer (surface layer)
31 cylindrical metal, 32 bearing, 33 conductive base, 34 charging member,
35 Stabilized power supply, 36 Ammeter 41 Bowl-shaped resin particles, 42 Conductive resin layer (binder)
51 Opening of bowl-shaped resin particles, 52 Concavity derived from opening of bowl-shaped resin particles 53 Edge of opening of bowl-shaped resin particles, 54 Height difference,
55 Maximum diameter of bowl-shaped resin particles 61 Opening, 62 Opening recess, 63 Minimum opening diameter 81 Bowl-shaped resin particle, 82 Conductive resin layer (binder)
91 Electron beam, 92 Conductive substrate, 93 DC power supply 101 Developing means, 102 Toner, 103 Image carrier (photosensitive member), 104 Transfer means 105 Exposure, 106 Developing sleeve, 107 Cleaning means,
108 Toner coating blade, 109 Magnetic field generating means 200 Charging means, 201 to 203 Bias applying means, 204 Heating and pressing means P Transfer material

Claims (4)

A charging step of charging the image carrier using a charging member in contact with the image carrier;
An electrostatic latent image forming step of forming an electrostatic latent image on the image carrier;
A development step of developing the electrostatic latent image with toner to form a toner image;
A transfer step of transferring the toner image to a recording medium with or without an intermediate transfer member, and a step of heating and fixing the toner image transferred to the recording medium;
An image forming method comprising:
The charging member has a conductive substrate and a conductive resin layer as a surface layer on the substrate,
The conductive resin layer contains a binder and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member,
The surface of the charging member includes a concave portion derived from the opening of the bowl-shaped resin particle exposed on the surface, and a convex portion derived from the edge of the opening of the bowl-shaped resin particle exposed to the surface. Have
The saturation magnetization of the toner is 15.0 Am ² / kg or more and 35.0 Am ² / kg or less at a magnetic field of 795.8 kA / m, and the dielectric constant ε ′ of the toner is 25.0 pF / m at a frequency of 10 kHz and a temperature of 40 ° C. An image forming method, wherein the image forming method is 40.0 pF / m or less.   The image forming method according to claim 1, wherein the toner contains 30 to 70 parts by mass of magnetic particles with respect to 100 parts by mass of the binder resin. A part of the surface of the charging member is constituted by the conductive resin layer,
The surface of the charging member is applied with an accelerating voltage of 1 kV and a magnification of 2000 using a scanning electron microscope in a state where a direct current voltage of 50 V or more and 100 V or less is applied between the electrode opposed to the charging member and the substrate. Observe at double,
K1, K2, and K3 satisfy the following mathematical formulas (1) to (3), where the brightness is K1 at the convex portion, the brightness K2 at the bottom of the concave portion, and the brightness K3 at the exposed surface of the conductive resin layer. The image forming method according to claim 1.
Formula (1) K2 <K1
Formula (2) K3 <K1
Formula (3) 0.8 ≦ K2 / K3 ≦ 1.2 The image carrier has a support, an undercoat layer formed on the support, and a photosensitive layer formed on the undercoat layer,
The volume resistivity of the undercoat layer is 1 × 10 ¹¹ Ω · cm or more and 1 × 10 ¹⁶ Ω · cm or less,
The image forming method according to claim 1, wherein the undercoat layer contains an electron transporting compound.