JP2017161824A - Process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process cartridge capable of giving a high quality image even in a low temperature environment and even in a low temperature and low humidity environment.SOLUTION: In a charging member 101 including a conductive base body and a conductive elastic layer as a surface layer, the elastic layer is configured to include a binder and hold bowl-shaped resin particles that each have an opening and are exposed on a surface of the elastic layer, and the elastic layer includes a recess derived from the opening of the bowl-shaped resin particles and a projection derived from an edge of the opening of the bowl-shaped resin particles. With the Martens hardness of the binder on the surface defined as M1, and the Martens hardness of the binder directly under a bottom part of the recess derived from the opening of the bowl-shaped resin particles defined as M2, M2/M1 satisfies less than 1. Toner contains silica fine particles as an external additive, with the silica fine particles obtained by treating 100 pts.mass of a silica original body with 15.0 to 40.0 pts.mass, inclusive, of silicone oil, and the silica fine particles having a fixation rate (%) of the silicone oil of 70% or more in terms of the amount of carbon.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a process cartridge used in a recording method using electrophotography or the like.

  Conventionally, in an electrophotographic system, an electrostatic latent image carrier (hereinafter also referred to as a photoconductor) made of a photoconductive material is charged by a charging device and further exposed to form an electrostatic image on the surface of the photoconductor. To do. Next, the electrostatic charge image is developed with toner on a toner carrier (hereinafter also referred to as a developing sleeve) to form a toner image, the toner image is transferred to a transfer material such as paper, and then heated and pressed onto the transfer material. The toner image is fixed to obtain a copy or print. At this time, the toner remaining on the photoreceptor without being transferred to the transfer material after transfer (hereinafter also referred to as transfer residual toner) is cleaned by various methods such as a cleaning blade, and the above-described steps are repeated.

  As the charging device, the surface of the photoconductor 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 disposed in contact with or close to the surface of the photoconductor. The method is adopted. From the viewpoint of stably charging and reducing the generation of ozone, a contact-type charging method is preferably used. In the case of the contact-type charging method, a roller-shaped charging member is preferably used.

On the other hand, reducing the diameter of the developing sleeve is an important technique in terms of downsizing. Charging of toner is performed mainly by frictional charging by rubbing between the toner and a frictional charging applying member such as a developing sleeve in a region where the toner is regulated by a toner regulating member (hereinafter also referred to as a developing blade).
In particular, in the case of the developing sleeve having a reduced diameter as described above, the developing area of the developing nip portion is narrowed, so that it is difficult for the toner to fly from the developing sleeve. For this reason, only a part of the toner is excessively charged, a so-called charge-up phenomenon occurs, and the toner tends to be non-uniformly charged.

In order to properly frictionally charge the entire toner even when the diameter of the developing sleeve is reduced, the toner is often replaced in an area where the developing sleeve and the developing blade are rubbed (hereinafter also referred to as blade nip). High circulation of toner is required. However, the deteriorated toner has poor circulatory properties, and the whole toner tends to be difficult to be frictionally charged properly.
That is, the toner deteriorated on the developing sleeve having a reduced diameter tends to be non-uniformly charged. When the toner is non-uniformly charged, various problems arise. One of them is that sufficient transferability cannot be obtained in the above-described transfer process, and the transfer residual toner increases on the photoreceptor.

  In order to stabilize the charging of the photoreceptor due to contact charging, Patent Document 1 discloses a charging member for contact charging provided with a surface layer having convex portions derived from resin particles or the like on the surface. The use of such a charging member surely tends to stabilize the charging of the photoreceptor. However, in the charging member described in Patent Document 1, the contact pressure is concentrated on the convex portions derived from the resin particles on the surface of the charging roller when contacting the photoreceptor, and the surface of the photoreceptor is not uniform over a long period of use. In some cases, vertical streak-like image defects may occur due to such uneven wear.

To deal with this problem, Patent Document 2 contains bowl-shaped resin particles having openings in the conductive resin layer, and the surface of the charging member has irregularities derived from the openings and edge portions of the bowl-shaped resin particles. A charging member having been proposed.
By using the charging member described in Patent Document 2, the edge portion of the opening of the bowl-shaped resin particles on the surface of the charging member (hereinafter also simply referred to as an edge portion) is elastically deformed, whereby The contact pressure is relieved. For the above reasons, there is a tendency that uneven wear of the photosensitive member can be suppressed even during long-term use.

JP 2008-276026 A JP 2011-237470 A

However, with recent high speed and high durability of electrophotography, not only non-uniform wear of the photoreceptor but also further improvement of stain resistance is required. The charging member described in Patent Document 2 can suppress uneven wear of the photosensitive member, but is not necessarily sufficient with respect to the adhesion resistance and contamination of toner and free external additives on the charging member.
In particular, in a low-temperature and low-humidity environment, toner fluidity tends to be high, toner slip-through is promoted, and dirt on the charging member that leads to image defects tends to become obvious. As a result, an image defect due to the accumulated dirt may occur.
Further, when the toner having a small diameter as described above is used and the toner tends to be charged up, the adhesion to the member is increased and the adhesion to the charging member tends to be promoted.

According to the further study by the present inventors, the reason why the charging member described in Patent Document 2 is soiled is that the contact area of the edge portion in the nip portion between the charging member and the photosensitive member increases, thereby causing contact. It is thought that dirt will easily adhere to the part.
With reference to FIG. 1, the mechanism of the occurrence of the adhesion of dirt will be described. As shown in FIG. 1 (1b), the elastic deformation of the bowl particles in the nip portion moves as the edge 11 of the bowl particles bends in the direction of arrow A as shown in FIG. 1 (1a). The contact area between the photoconductor 13 and the edge portion 11 is increased. As a result, the present inventors consider that the adhesion of dirt occurs. Note that the nip is two straight lines parallel to the longitudinal direction of the charging member passing through the respective contact points at two locations at both ends of the contact point between the charging member and the photosensitive member in the direction orthogonal to the longitudinal direction of the charging member. In this case, it is defined that the area is sandwiched.

As a means for suppressing dot-like and horizontal streak-like images due to adhesion of dirt due to an increase in the contact area between the photoconductor 13 and the edge portion 11, the hardness of the conductive elastic layer 12 around the edge portion 11 is spread over the entire area. A method of increasing the height and suppressing the bending of the edge 11 in the direction of arrow A is conceivable.
However, in such a case, the bending of the edge portion 11 can be suppressed, but the contact pressure cannot be relieved. Therefore, the contact pressure is concentrated at the contact point between the photoconductor 13 and the edge portion 11, and long-term In use over a long period of time, non-uniform wear of the photoreceptor occurs. That is, it is necessary to solve both the high speed and the high durability of electrophotography to achieve both the prevention of dirt fixing and the uneven wear of the photoreceptor.

  The present invention suppresses white spot-like image defects due to the fusion of the photoconductor even in a low temperature environment by satisfying both the suppression of the adhesion of dirt and the non-uniform wear of the photoconductor as described above. A process cartridge capable of obtaining a high-quality image is provided. Further, the present invention provides a process cartridge capable of obtaining a high-quality image in which black spot-like image defects due to contamination of the charging member are suppressed even in a low temperature and low humidity environment.

As a result of intensive studies, the present inventors have found that the above-described problems can be solved by employing the following toner, and have reached the present invention.
That is, in the process cartridge that can be attached to and detached from the image forming apparatus main body,
The process cartridge is
An electrostatic latent image carrier;
A charging member for charging the electrostatic latent image carrier;
Developing means for developing the electrostatic charge image formed on the electrostatic latent image carrier using toner;
Have
The charging member has a conductive base and a conductive elastic layer as a surface layer on the conductive base,
The elastic layer comprises 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 particles exposed on the surface, a convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed to the surface, Have
When the Martens hardness of the binder on the surface of the charging member is M1, and the Martens hardness of the binder immediately below the bottom of the concave portion of the charging member is M2, the value of M2 / M1 is less than 1,
The toner contains silica fine particles as an external additive,
The silica fine particles are treated with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil based on 100 parts by mass of the silica raw material, and the carbon oil-based immobilization ratio (%) of the silicone oil is It is related with the process cartridge characterized by being 70% or more.

  According to the present invention, it is possible to provide a process cartridge capable of obtaining a high-quality image in which white spot-like image defects due to photoconductor fusion are suppressed even in a low temperature environment. Further, it is possible to provide a process cartridge capable of obtaining a high-quality image in which black spot-like image defects due to contamination of the charging member are suppressed even in a low temperature and low humidity environment.

It is explanatory drawing of the deformation | transformation in the nip part of the conventional charging member. It is explanatory drawing of the deformation | transformation in the nip part 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 the schematic of the electric current measurement apparatus of a charging member. FIG. 3 is a partial cross-sectional view of the vicinity of the surface of the charging roller according to the present invention. FIG. 3 is a partial cross-sectional view of the vicinity of the surface of the charging roller according to the present invention. It is explanatory drawing of the shape of the bowl-shaped resin particle used for this invention. It is explanatory drawing of the hardness measurement position in the surface of a charging member. It is the schematic of the jig which contacts the surface of a glass plate and a charging member. It is explanatory drawing of the space formed between a glass plate and a charging member. 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.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to these descriptions.
As a result of intensive studies, the present inventors have found that the above-described problems can be solved by employing the following process cartridge, and have reached the present invention.
That is, in the process cartridge that can be attached to and detached from the image forming apparatus main body,
The process cartridge includes an electrostatic latent image carrier, a charging member that charges the electrostatic latent image carrier, and a developing unit that develops the electrostatic image formed on the electrostatic latent image carrier using toner. And have.
The charging member has a conductive substrate and a conductive elastic layer as a surface layer on the conductive substrate.
The elastic 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.
The surface of the charging member includes a concave portion derived from the opening of the bowl-shaped resin particles exposed on the surface, a convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed to the surface, Have
When the Martens hardness of the binder on the surface of the charging member is M1, and the Martens hardness of the binder immediately below the bottom of the concave portion of the charging member is M2, the value of M2 / M1 is less than 1.
The toner contains fine silica particles as an external additive.
The silica fine particles are treated with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil based on 100 parts by mass of the silica raw material, and the carbon oil-based immobilization ratio (%) of the silicone oil is 70% or more.

First, a description will be given of the reason for the occurrence of a white spot-like image defect due to photoconductor fusion. As described above, the charging member is generally contaminated by the following phenomenon.
The transfer residual toner and the external additive are originally to be removed by a cleaning blade or the like in the cleaning process. However, transfer residual toner and external additives may pass through the cleaning blade due to vibration of the cleaning blade and minute scratches on the photoconductor, and may remain on the photoconductor even after a cleaning process. Such a toner component causes contamination of the charging member by contact with the charging member.

In the study by the present inventors, it has been found that not only the toner but also an external additive component such as silica fine particles released from the toner is the cause of the stain.
As described above, the dirt adheres to the charging member, the dirt is transferred from the charging member to the photosensitive member, and the toner is fused to the photosensitive member by being pressed by the charging member ( Hereinafter, it is also referred to as photoconductor fusion).
When photoconductor fusion occurs, a white spot-like image defect appears on the halftone or solid black image at the fusion portion in the photoconductor cycle.

On the other hand, if the silica particles that are more likely to slip through the cleaning blade than the toner are the main factor in the contamination of the charging member, the charging ability of the charging member is reduced due to the charge up of the silica, so that the toner is placed on the non-image area, Prone to black spotted image defects.
That is, there is a tendency that the control of black spot-like image defects caused by silica fine particles is more severe than the white spot-like image defects caused by photoconductor fusion, and a specific toner and a specific charging member are used as in the present invention. It needs to be used and more strictly controlled.
An object of the present invention is to suppress these white spot-like image defects and black spot-like image defects by using a specific charging member and a specific toner.

Here, the charging member in the present invention will be described.
The charging member according to the present invention is a charging member having a conductive substrate and a conductive elastic layer as a surface layer on the substrate.
The conductive elastic layer contains a binder resin and bowl-shaped resin particles, and the bowl-shaped resin particles are exposed on the surface of the elastic layer. 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 an edge portion of the opening of the bowl-shaped resin particles (hereinafter also simply referred to as an edge portion). doing.

Further, when the Martens hardness of the binder on the surface is M1, and the Martens hardness of the binder immediately below the bottom of the concave portion derived from the opening of the bowl-shaped resin particles on the surface of the charging member is M2, the value of M2 / M1 is It is characterized by being less than 1. Furthermore, it is more preferable that M2 / M1 is 0.7 or less.
In order to keep M1 and M2 within the above range, a means for using a bowl-shaped resin particle bowl material having a low oxygen permeability and oxidizing and hardening the surface of the charging member by heat treatment in an air atmosphere is preferable. . The above will be described in detail later.

(1) Charging Member FIG. 3 shows a schematic diagram of an example of a cross section of the charging member.
The charging member in FIG. 3 (3 a) has a conductive base 1 and a conductive elastic layer 2.
As shown in FIG. 3 (3 b), the conductive elastic layer may have a two-layer configuration including a conductive elastic layer 21 and a conductive elastic layer 22. The conductive elastic layer contains a binder and bowl-shaped resin particles.
The conductive substrate 1 and the conductive elastic layer 2 or the layers sequentially laminated on the conductive substrate 1 (for example, the conductive elastic layer 21 and the conductive elastic layer 22 shown in FIG. 3 (3b)) are made of an adhesive. You may adhere through. In this case, the adhesive is preferably conductive. A known adhesive can be used as the conductive adhesive.

Examples of the binder 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 can be used alone or in combination of two or more.

(1-1) Conductive substrate The conductive substrate is conductive and has a function of supporting a conductive elastic layer provided thereon. Examples of the material include metals such as iron, copper, stainless steel, aluminum, and nickel, and alloys thereof.

(1-2) Conductive Elastic Layer FIG. 5 is a partial sectional view near the surface of the conductive elastic layer constituting the elastic layer of the roller member. Some bowl-shaped resin particles 41 contained in the conductive elastic layer are exposed on the surface of the roller member. The surface of the roller member has a recess 52 derived from the opening 51 of the bowl-shaped resin particles exposed on the surface, and a protrusion derived from the edge 53 of the opening of the bowl-shaped resin particles exposed on the surface. And have.

The height difference 54 between the bottom of the concave portion 52 and the apex 53 of the convex portion derived from the opening of the bowl-shaped resin particles shown in FIG. 6 is preferably 5 μm or more and 100 μm or less, and preferably 10 μm or more and 80 μm or less. More preferred. By setting it as this range, the point contact of the edge in a nip part can be maintained more reliably.
Further, the ratio of the height difference 54 between the top 53 of the convex part and the bottom part 52 of the concave part and the maximum diameter 55 of the bowl-shaped resin particles, that is, the [maximum diameter] / [height difference] of the resin particles is: It is preferable that it is 0.8 or more and 3.0 or less. By setting it as this range, the point contact of the edge in a nip part can be maintained more reliably.

  It is preferable that the surface state of the conductive elastic 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 setting it as said range, the point contact of the edge in a nip part can be maintained more reliably. The method for measuring the surface ten-point average roughness (Rzjis) and the surface irregularity average interval (Sm) will be described in detail later.

  FIG. 7 (7a) to (7e) show an example of bowl-shaped resin particles used in the present invention. In the present invention, the bowl shape refers to a shape having an opening 61 and a rounded recess 62 below the opening. The opening may have a flat edge as shown in FIGS. 7 (a) and (7b), and the edges may be uneven as shown in FIGS. 7 (c) to (e). Also good.

  The standard of 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 of the bowl-shaped resin particles / [minimum diameter of the opening]} is 1.1 or more. It is more preferable that it is 4.0 or less. By adopting this range, the bowl particles can move more reliably to the binder side at the nip portion described later.

  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. By setting it as this range, the bowl particle can move more reliably to the binder side at the nip portion described later. The maximum thickness of the shell is preferably 3 times or less of the minimum thickness, and more preferably 2 times or less.

[binder]
As the binder contained in the conductive elastic layer according to the present invention, a known rubber or resin can be used. 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.

[Conductive fine particles]
As a measure of the volume resistance of the conductive elastic 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%. It becomes easier to appropriately charge the electrophotographic photosensitive member by discharge. Therefore, you may contain well-known electroconductive fine particles in order to express electroconductivity in an electroconductive elastic layer. Examples of the conductive fine particles include metal oxides, metal fine particles, and carbon black. Moreover, these electroconductive fine particles can be used individually or in combination of 2 or more types. As a standard of the content of the conductive fine particles in the conductive elastic layer, it is preferably 2 to 200 parts by weight, more preferably 5 to 100 parts by weight with respect to 100 parts by weight of the binder.

[Method of forming conductive elastic layer]
A method for forming the conductive elastic layer is exemplified below. First, a coating layer (hereinafter also referred to as a preliminary coating layer) in which hollow resin particles are dispersed in a binder is prepared on a conductive substrate. Then, by polishing the surface, a part of the hollow resin particles are removed to form a bowl shape, which is derived from the concave portion derived from the opening of the bowl-shaped resin particle and the edge of the opening of the bowl-shaped resin particle. Protrusions are formed. (Hereinafter, it is also referred to as “uneven shape derived from the opening of the bowl-shaped resin particles”). In this way, a conductive resin layer is formed, and then heat-cured by performing a heat treatment.

[Dispersion of resin particles in pre-coating layer]
A method for dispersing hollow resin particles in the preliminary coating layer will be described.
As one method, there can be exemplified a method of drying, curing, cross-linking or the like of a conductive resin composition in which hollow particles containing a gas inside the particles are dispersed together with a binder. As the resin used for the hollow resin particles, a resin having a polar group is preferable from the viewpoint of low gas permeability and high resilience, and a resin having a unit represented by the following formula (4) is more preferable. . In particular, it is more preferable to have both the unit represented by the formula (4) and the unit represented by the formula (8) from the viewpoint of easy control of the polishing properties.

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

(In the formula, 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. R ² and R ³ are The structure may be the same or different.)

  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 together with 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 this 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 the resin to be used. 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, it is particularly preferable to use at least one thermoplastic resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, and methacrylonitrile resin, which has low gas permeability and high resilience, in the hardness distribution described later. It is more preferable in controlling. These thermoplastic resins can be used alone or in combination of two or more. Furthermore, these thermoplastic resin monomers may be copolymerized to form a copolymer.

  The substance to be encapsulated in the thermoplastic 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, 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 polymerizable 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 weight part 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. When using 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. When using 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 with a disperser etc., it may transfer to a pressure-resistant container and suspension polymerization may be carried out, and you may suspend in a pressure-resistant container. The polymerization temperature is preferably 50 ° C to 120 ° C. The polymerization may be carried out under atmospheric pressure, but under pressure (at a pressure obtained by adding 0.1 to 1 MPa to atmospheric pressure) so as not to vaporize the substance encapsulated in the thermal expansion microcapsule. Is preferred. 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]
A method for forming the preliminary coating layer will be described. As a method of forming the preliminary coating layer, electrostatic spray coating, dipping coating, roll coating, a method of bonding or coating a sheet-shaped or tube-shaped layer formed in a predetermined film thickness, and a predetermined shape in a mold There is a method of curing and molding the material. 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. Thereafter, after drying, curing, or cross-linking, the surface of the preliminary coating layer is polished to remove a part of the hollow resin particles 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 particles, In many cases, convex portions derived from hollow resin particles are formed. In this case, a part of the convex portions of the hollow resin particles can be deleted to form a bowl shape, and an uneven shape derived from the opening of the bowl-shaped resin particles can be formed. In this case, it is more preferable to use tape polishing in which the pressure applied to the charging member 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.

  In the polishing tape, abrasive grains are dispersed in a resin and applied to a sheet-like substrate. Examples of the abrasive grains include aluminum oxide, chromium oxide, 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 diameter of the abrasive grains is a volume-based median diameter D50 measured by a centrifugal sedimentation method. The range of the count of the polishing tape having the abrasive grains is preferably 500 or more and 20,000 or less, and more preferably 1,000 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 KOVAX), microfinishing film, wrapping film (trade name, Sumitomo 3M Co., Ltd.), mirror film, wrapping film (product) Name, Sankyo Rikagaku Co., Ltd.), Mibox (trade name, manufactured by Nihon Micro Coating 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 rotation speed is preferably set to 10 rpm or more and 1,000 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 derived from the opening of a bowl-shaped resin particle can be more easily formed in the surface of a conductive resin layer.

(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, On the surface, there may be a case where the convex portions derived from the hollow resin particles are not formed. In such a case, it is possible to form a concavo-convex shape derived from the opening of the bowl-shaped resin particles by utilizing the difference in abrasiveness between the hollow-shaped resin particles and 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 preliminary coating layer in the above state is polished, the hollow resin particles can be formed into a bowl shape in which only a part of the hollow resin particles are removed without being polished in the same state as the preliminary coating layer. Thereby, the uneven | corrugated shape derived from the opening of a bowl-shaped resin particle can be formed in the surface of a preliminary coating layer. Since this method is a method of forming a concavo-convex shape using the difference in polishing properties between the hollow resin particles and the preliminary coating layer, rubber can be used as the binder used for the preliminary coating layer. preferable. 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 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 is as short as possible or not performed.

  As an example, the rotational speed of the plunge cut type cylindrical grinding wheel is preferably 1,000 to 4,000 rpm, particularly preferably 2,000 to 4,000 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 shape derived from the opening of a bowl-shaped resin particle can be more easily formed in the surface of a conductive elastic layer.

(1-3) Hardness Distribution Control Method In the charging member according to the present invention, S shown in the following formula (1) satisfies the range shown in the same formula (1), and d shown in the following formula (2) is the same formula ( It is preferable to satisfy the range shown in 2). Therefore, as described above, when the Martens hardness of the binder portion (F of FIG. 8) on the surface of the charging member is M1, and the Martens hardness of the lower part of the bowl-shaped resin particles (E of FIG. 8) is M2, The value M (M2 / M1) obtained by dividing M2 by M1 is less than 1. More preferably, M is 0.7 or less.
As means for keeping M within the above range, the material of the bowl-shaped resin particle bowl described above is made of a material having a low oxygen permeability, and the surface of the charging member is oxidatively cured by heat treatment in an air atmosphere. Means are preferred.

  In the heat treatment in the air atmosphere, the Martens hardness increases due to oxidative crosslinking. The degree of this oxidative crosslinking is affected by the heat treatment temperature and the oxygen concentration in the crosslinked part. As for the oxygen concentration, the higher the oxygen concentration in the cross-linking portion, the greater the progress of oxidation cross-linking. Therefore, by controlling the oxygen gas permeability of the shell material of the bowl-shaped resin particles, it is possible to control the Martens hardness immediately below the bowl particles (E in FIG. 8).

Specifically, when the oxygen gas permeability of the shell material of the bowl particles is small, the Martens hardness M1 of the binder portion (F in FIG. 8) on the surface of the charging member increases with the progress of the oxidation crosslinking. On the other hand, the Martens hardness M2 immediately below the bowl particles (E in FIG. 8) is low in oxygen gas permeability of the shell material of the bowl particles, so that the supply amount of oxygen is reduced, compared with the surface of the charging member, Oxidative crosslinking is difficult to proceed. Therefore, M2 is smaller than M1. When M1 is large, the deflection of the convex portion derived from the edge portion at the nip portion is suppressed, and the point contact maintaining ability is increased. In addition, since M2 is smaller than M1, the bowl-shaped resin particles can sink to the elastic layer binder side (vertical direction) as shown by the arrow B in FIG. It becomes.
As a result, the contact pressure can be alleviated by the bowl particles themselves having a load on the edge portion sinking toward the elastic layer binder while maintaining point contact.

  On the other hand, when the oxygen gas permeability of the shell material of the bowl particles is large, sufficient oxygen is also supplied directly below the bowl, so that the Martens hardness M1 and M2 are approximately the same. For this reason, it becomes difficult for the bowl-shaped resin particles to sink to the elastic layer binder side (vertical direction) as shown by the arrow B in FIG. 2 (2a), and the contact pressure cannot be reduced appropriately. In some cases, the photoconductor may be unevenly worn.

As for the heat treatment method, known means such as a hot air continuous furnace, an oven, a near infrared heating method, a far infrared heating method can be used, but the surface of the charging member is heated in an air atmosphere. If possible, the method is not particularly limited to these methods.
The effect of oxidative crosslinking by heating is promoted as the temperature is high. However, if the temperature is too high, shrinkage due to volatilization of low molecular components of the binder occurs. Therefore, the heating temperature is preferably 180 to 240 ° C. ° C is more preferred.
Moreover, since the effect of oxidative crosslinking is promoted for the binder described above, styrene butadiene rubber (SBR), butyl rubber, acrylonitrile butadiene rubber (NBR), which has a double bond in the bond and has high heat resistance, Chloroprene rubber (CR) and butadiene rubber (BR) are preferred.

(2) Electrophotographic apparatus FIG. 10 shows a schematic configuration of an example of an electrophotographic apparatus.
The electrophotographic apparatus includes an electrophotographic photosensitive member, a charging device, a latent image forming device, a developing device, a transfer device, a cleaning device, and a fixing device.
The electrophotographic photosensitive member 102 is a rotary drum type having a photosensitive layer on a conductive substrate. The electrophotographic photosensitive member is driven to rotate at a predetermined peripheral speed (process speed) in the direction of the arrow.

The charging device includes a contact-type charging roller 101 that is placed in contact with the electrophotographic photosensitive member 102 by contacting the electrophotographic photosensitive member 102 with a predetermined pressing force. The charging roller 101 is driven rotation that rotates according to the rotation of the electrophotographic photosensitive member 102, and uniformly charges the electrophotographic photosensitive member 102 to a predetermined potential by applying a predetermined DC voltage from the charging power source 109. .
A latent image forming apparatus (not shown) forms an electrostatic latent image on the electrophotographic photosensitive member 102. As the latent image forming apparatus, for example, an exposure apparatus such as a laser beam scanner is used. An electrostatic latent image is formed by irradiating the uniformly charged electrophotographic photosensitive member 102 with exposure light 107 corresponding to image information.

The developing device includes a developing sleeve or a developing roller 103 disposed close to or in contact with the electrophotographic photosensitive member 102. The electrostatic latent image is developed by reversal development using toner electrostatically processed to the same polarity as the charged polarity of the electrophotographic photosensitive member to form a toner image.
The transfer device has a contact-type transfer roller 104. The toner image is transferred from the electrophotographic photosensitive member to a transfer material such as plain paper. The transfer material is conveyed by a paper feeding system having a conveying member.

The cleaning device includes a blade-type cleaning member 106 and a collection container 108, and after the toner image is transferred, the transfer residual toner remaining on the electrophotographic photosensitive member 102 is mechanically scraped and collected.
Here, it is possible to omit the cleaning device by adopting a development simultaneous cleaning system in which the transfer device collects the transfer residual toner.
The fixing roller 105 is constituted by a heated roll, fixes the transferred toner image onto the transfer material, and discharges the transfer material with the toner image fixed to the outside of the apparatus.

(3) Process Cartridge FIG. 11 shows a schematic configuration of an example of the process cartridge. The process cartridge is configured such that the electrophotographic photosensitive member 102, the charging roller 101, the developing roller 103, the cleaning member 106, and the like are integrated, and is detachable from the electrophotographic apparatus. The charging member according to the present invention includes a charging member. When pressed against the glass plate, it is preferable to satisfy the relationship represented by the following formula (1).
S1 is a region including at least one contact portion between the charging member and the glass plate in the nip between the charging member and the glass plate when pressed to a load of 100 (g). The average contact area per contact portion between the charging member and the glass plate is shown.
S5 shows the said average contact area when pressing so that the load with respect to this glass plate may be 500 (g).

The nip is a contact portion between the charging member and the glass plate. More specifically, each of two locations at both ends of the contact point between the charging member and the glass plate in the direction orthogonal to the longitudinal direction of the charging member. A region sandwiched between two straight lines parallel to the longitudinal direction of the charging member passing through the contact point is defined.
Furthermore, the charging member according to the present invention preferably satisfies the relationship represented by the following formula (2).
d1 represents the average spatial distance of the space 85 between the charging member and the glass plate shown in FIG. 9 (9b) when the charging member is pressed against the glass plate so as to have a load of 100 (g).
d5 shows an average spatial distance when the glass plate is pressed so that the load is 500 (g). A method for calculating the average spatial distance will be described later.

  As shown in FIG. 2 (2 d), the contact state between the charging member 14 and the photosensitive member 13 is from immediately after the nip entry (position H) through the center of the nip (position I) and immediately before contact release (J The position has changed. At this time, the partial load at the position I is different from the partial load at the positions H and J. It can be considered that there is almost no load at the position where the nip enters or not (position G) and the position immediately after the contact release (position K). However, in a general electrophotographic apparatus, in a range from H to J (here, defined as a range that occupies about 90% of the nip portion), a change in load can be expected to be within 5 times. . Therefore, by taking the ratio when the load is changed by a factor of 5, it is possible to simulate a change in the contact state ranging from H to J with respect to the contact state between the charging member and the photosensitive member. .

In order to evaluate the contact state as accurately as possible, the present inventors consider that the lower limit of the load in a general electrophotographic apparatus is 100 g. Was determined to be preferable. Therefore, the contact state is evaluated using 100 g and 500 g which is five times the contact load.
The contact area ratio S between the two contact loads shown in the above formula (1) indicates how much the convex portion derived from the edge portion is in point contact with the photosensitive member when the contact load is changed from 100 g to 500 g. It is a value indicating whether or not the state can be maintained. That is, S can be said to be an index for evaluating the ability of the charging member according to the present invention to maintain a point contact state with respect to the photoreceptor (hereinafter also referred to as a point contact state maintaining ability) in the charging member nip portion. Specifically, when the value of S is small, the point contact state maintaining ability is high, and vice versa when it is large.

  In FIG. 2 (2d), the partial load applied to the surface of the charging member increases from the position H immediately after entering the nip portion to the position of the center I of the nip portion. As shown in 1a), the edge portion 11 bends in the direction of arrow A. When the point contact state maintaining ability of the charging member is low, the contact area between the photoconductor 13 and the edge portion 11 is increased as shown in FIG. 1 (1b). In such a case, there is a high possibility that dirt adheres to the surface of the charging member described above.

In the charging member according to the present invention, S preferably satisfies the range shown in Formula (1). If S is 0.5 or less (S ≦ 0.5), as described above, the ability of the charging member to maintain the point contact state while in contact with the surface of the photoreceptor increases. Regarding the reason why the lower limit of S is set to 0.2, in the present configuration in which the elastic layer binder contains bowl-shaped resin particles, a means for making S less than 0.2 is found in a material and manufacturing method that can withstand practical use. Because it was not possible.
Further, S is more preferably 0.2 to 0.3. By setting it as this range, the charging member expresses a higher ability to maintain a point contact state, and can further enhance the effect of suppressing the adhesion of dirt.

  The ratio d of the average spatial distance in the two contact loads shown in the equation (2) is (how much between the surface of the charging member and the photosensitive member when the contact load is changed from 100 g to 500 g). This is an index indicating whether the space can be maintained, specifically, when the value of d is small, the space maintaining ability is high, and vice versa when the value is large. The deformation state of the bowl-shaped resin particles in the nip portion can be evaluated.

  The charging member according to the present invention has a high point contact state maintaining ability as described in the formula (1). That is, by satisfying the formula (1), the movement (deformation) of the bowl-shaped resin particles from the shape shown in FIG. 1 (1a) to the shape shown in (1b) can be suppressed. The movement of the bowl-shaped resin particles in the nip portion on the surface of the charging member having a high point contact state maintaining ability that satisfies the above conditions will be considered below.

In FIG. 2 (2d), the partial load applied to the surface of the charging member increases from the position H immediately after entering the nip to the position of the center I of the nip.
When the point contact state maintaining ability on the surface of the charging member is high, the bowl-shaped resin particles move so that the edge portion 11 bends in the direction of arrow C as shown in FIG. Thereby, the bowl-shaped resin particles themselves move in the direction of the arrow B, that is, the elastic layer binder 12 side.
When the space maintaining ability of the charging member is high, that is, when d is small, it can be considered that the shape as shown in FIG. 2B is maintained near the position of the center I of the nip portion. The above-described movement of the bowl particles, which are loaded on the edge portion due to the contact, sinks to the elastic layer binder side, so that the contact pressure can be relaxed, thereby suppressing uneven wear of the photoreceptor. It becomes possible.

  On the other hand, when the space maintaining ability of the charging member is low, it can be considered that the state shown in FIG. Although the movement of the bowl-shaped resin particle itself sinking into the elastic layer binder occurs, if the space maintenance ability is low, the space in the vicinity of the edge portion is reduced, so that the surface of the charging member is soiled. Is likely to occur.

  On the other hand, when the space maintaining ability of the surface of the charging member is very high, that is, when d is close to 0, the bowl-shaped resin particles are not elastically deformed. In the above case, since the relaxation of the contact pressure due to the bowl-shaped resin particles does not occur, the above-mentioned non-uniform wear of the photoconductor occurs.

In the charging member according to the present invention, it is preferable that d satisfies the range represented by the formula (2). If d is 0.5 or less (d ≦ 0.5), as described above, the charging member has a high space maintaining ability with the surface of the photoreceptor. If d is 0.15 or more (0.15 ≦ d), the bowl-shaped resin particles can be elastically deformed, so that the contact pressure against the photoreceptor can be reduced.
d is more preferably 0.4 to 0.5. By setting it within this range, the charging member can exhibit a higher effect on the space maintaining ability and the relaxation of the contact pressure against the photosensitive member.

The toner according to the present invention needs to contain silica fine particles. The toner preferably contains 0.40 parts by mass or more and 1.50 parts by mass or less, and more preferably 0.50 parts by mass or more and 1.30 parts by mass or less of the silica fine particles per 100 parts by mass of the toner particles.
By controlling the content of the silica fine particles within the above range, the fluidity of the toner can be controlled to an appropriate state, the toner can be prevented from being deteriorated, and an excellent image can be provided even after long-term use.
When the content of the silica fine particles is less than 0.40 parts by mass, the fluidity of the toner is insufficient, the deterioration of the toner is promoted, and an excellent image cannot be obtained when used for a long time.

In particular, the silica fine particles in the present invention are treated with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil based on 100 parts by mass of the silica raw material, and the carbon oil-based immobilization rate of the silicone oil. (%) Needs to be 70% or more.
Here, the carbon-based immobilization rate of the silicone oil corresponds to the amount of silicone oil molecules chemically bonded to the surface of the silica base.
In the silica fine particles used in the toner according to the present invention, the cohesiveness between the silica fine particles and the coefficient of friction can be controlled within the ranges necessary for the present invention by controlling the number of treatment parts and the immobilization ratio with the silicone oil within the above ranges.
The same properties can be imparted to the toner externally added with the silica fine particles.

That is, as a result of investigations by the present inventors, it has been found that in such a toner, the releasability from the member is easily improved. As a result, for example, the toner that contacts the developing sleeve or the developing blade easily moves, and the toner that is not in contact also moves in conjunction therewith, so that the toner circulation in the blade nip is likely to be improved.
As a result, rubbing at the blade nip is performed on each toner particle, and the toner is easily charged uniformly.
In the case of the toner as described above, the releasability from the member is easily maintained even in a toner that is deteriorated due to so-called durability, in which silica fine particles are embedded in the toner through a repeated paper passing test.

Although details of these effect expression mechanisms are not known, the inventors presume as follows.
In general, it is known that when the number of silicone oil parts added to the silica base increases, the releasability from the developing sleeve and the developing blade is improved due to the low surface energy property of the silicone oil molecules. On the other hand, due to the affinity between the molecules of silicone oil, the releasability or cohesiveness between the silica particles deteriorates, and the friction coefficient between the silica particles increases. The present invention is characterized by silica fine particles having a relatively large number of silicone oil-treated parts and a high immobilization rate. Such silica fine particles can increase the coefficient of friction without deteriorating the cohesiveness between the silica fine particles. The present inventors consider that the deterioration of cohesiveness can be reduced by fixing the terminal of the silicone oil molecule to the surface of the silica base material.

  Next, the influence on the toner surface when the silica fine particles are externally added to the toner particles will be described. When the toners are in contact with each other, microscopically, the contact between the silica fine particles present on the surface of the toner particles is dominant, so that the toner is also strongly influenced by the properties of the silica fine particles. For this reason, the toner according to the present invention is a toner in which the coefficient of friction between the toners is increased without deteriorating the cohesiveness between the toners, and the releasability from the developing sleeve or the developing blade is improved. It can be said.

By increasing the coefficient of friction without deteriorating the cohesiveness between the toners, when the toner in contact with the developing blade or the developing sleeve moves, the toner that is not in contact with the developing blade or the developing sleeve is removed by a sufficient frictional force between the toners. Can move. As a result, a large toner circulation can be created in the blade nip.
In the present invention, the intended effect of the present invention can be obtained by a synergistic effect by using such a toner having improved circulation and releasability and a specific charging member.

Although the details of the mechanism are not clear, the present inventors consider as follows.
As described above, a toner that has high releasability with respect to a member and that can circulate a large amount of toner that is in contact with or not in contact with the member due to sufficient frictional force between the toners has not been transferred. Also, the adhesion to the cleaning blade is very low.
It is known that slipping of toner and external additives from the cleaning blade is likely to occur when the cleaning blade vibrates when the toner adheres to a part of the cleaning blade. That is, in the toner according to the present invention, it is considered that the amount of toner and external additive slipping from the cleaning blade can be reduced due to the above reason.

Further, the toner and silica fine particles that have passed through reach the charging member. However, as described above, the charging member according to the present invention has a high point contact state maintaining ability, and the toner and silica fine particles are difficult to adhere.
That is, in addition to a small amount of toner and external additives that pass through, the toner and the silica fine particles themselves have high releasability and are difficult to adhere. Further, from the characteristics of the charging member according to the present invention, the toner and silica fine particles on the charging member Adhesion can be greatly reduced.

As a result, by combining the toner according to the present invention and the charging member, white spot-like image defects due to the fusion of the photoconductor due to the toner adhering to the charging member can be suppressed even in a low temperature environment. Can do.
Furthermore, it is also possible to suppress black spot-like image defects caused by silica fine particles that are more likely to pass through the cleaning blade than the toner adhere to the charging member.

  When the number of parts treated with the silicone oil is less than 15.0 parts by mass, a sufficient friction coefficient cannot be obtained, and in particular, the reduction of the toner photoreceptor fusion of the toner is not sufficiently performed. Insufficient for suppressing image defects. On the other hand, when the amount is more than 40.0 parts by mass, a sufficient friction coefficient can be obtained, but it is difficult to control the immobilization rate within an appropriate range. Releasability is also likely to deteriorate, which is insufficient for suppressing black spotted images.

Further, when the carbon oil-based immobilization rate of the silicone oil is less than 70%, the cohesiveness between the silica fine particles deteriorates. Therefore, under the severe evaluation conditions as described above, white spot-like image defects and black spot-like spots. Image defects cannot be improved.
The number of parts of the silica fine particles treated with silicone oil is preferably 17.0 parts by mass or more and 30.0 parts by mass or less with respect to 100 parts by mass of the silica raw material. The conversion rate (%) is preferably 90% or more.

As described above, the silica fine particles used in the present invention are produced by hydrophobizing with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil with respect to 100 parts by mass of the silica raw material. The degree of the hydrophobization treatment is preferably 70% or more, more preferably 80% or more, as measured by the methanol titration test from the viewpoint of suppressing a decrease in chargeability in a high-temperature and high-humidity environment. preferable.
Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil.

  In the present invention, the kinematic viscosity at 25 ° C. of the silicone oil used for the treatment of the silica fine particles is preferably 30 cSt or more and 500 cSt or less. When the kinematic viscosity is in the above range, it is easy to control the uniformity when the silica base is hydrophobized with silicone oil. Furthermore, the kinematic viscosity of the silicone oil is closely related to the molecular chain length of the silicone oil, and when the kinematic viscosity is in the above range, it is preferable because the aggregation degree of the silica fine particles can be easily controlled in a suitable range. A more preferable range of the kinematic viscosity at 25 ° C. of the silicone oil is 40 cSt or more and 300 cSt or less. Examples of the apparatus for measuring the kinematic viscosity of silicone oil include a capillary type kinematic viscometer (manufactured by Kashiwagi Scientific Instruments Co., Ltd.) or a fully automatic microkinematic viscometer (manufactured by Viscotech Co., Ltd.).

  The silica fine particles used in the present invention are preferably those obtained by treating at least one of alkoxysilane and silazane after treating the silica raw material with silicone oil. By doing so, since the surface of the silica base material that could not be hydrophobized with silicone oil can be hydrophobized, silica particles with a high degree of hydrophobization can be stably obtained. Further, it is preferable because the ease of toner loosening can be greatly improved. Although details of the reason why the ease of unraveling can be improved are not clear, the present inventors consider as follows. Of the silicone oil molecule ends on the surface of the silica fine particles, only one end has a degree of freedom, which affects the cohesiveness between the silica fine particles. On the other hand, by carrying out the two-stage treatment as described above, the silicone oil molecular terminal is hardly present on the outermost surface of the silica fine particles, so that the cohesiveness of the silica fine particles can be further reduced. As a result, the cohesiveness between the toners when externally added can be greatly reduced, and the ease of toner loosening can be improved.

In the present invention, the silica base material is, for example, so-called wet silica produced by vapor phase oxidation of silicon halide, so-called dry process or dry silica called fumed silica, and water glass. Both can be used.
The silica fine particles used in the present invention may be crushed during the treatment step or after the treatment step. Furthermore, when performing a two-stage process, it is also possible to perform a crushing process between processes.

The surface treatment with the silicone oil and the surface treatment with the alkoxysilane and silazane may be either a dry treatment or a wet treatment.
The specific procedure of the surface treatment with the silicone oil of the silica raw material is, for example, by reacting the silica fine particles in a solvent (preferably adjusted to pH 4 with an organic acid or the like) in which the silicone oil is dissolved. Remove. Thereafter, crushing treatment may be performed.

  Subsequently, a surface treatment with at least one of alkoxysilane and silazane is performed. In this case, the crushed silicone oil-treated silica fine particles are put into a solvent in which at least one of alkoxysilane and silazane is dissolved and reacted, and then the solvent is removed and crushed. Further, the following method may be used. For example, in the surface treatment with silicone oil, silica fine particles are put into a reaction vessel. Then, alcohol water is added with stirring in a nitrogen atmosphere, silicone oil is introduced into the reaction tank to perform surface treatment, and the mixture is further heated and stirred to remove the solvent, followed by crushing treatment. In the surface treatment with at least one of alkoxysilane and silazane, the surface treatment is performed by introducing at least one of alkoxysilane and silazane while stirring in a nitrogen atmosphere, and further, the mixture is heated and stirred to remove the solvent and then cooled.

Preferred examples of the alkoxysilane include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and phenyltriethoxysilane. On the other hand, hexamethyldisilazane can be preferably exemplified as silazane.
The amount of treatment with at least one of alkoxysilane and silazane is 0.1 parts by mass or more and 20.0 parts by mass or less as a total amount of at least one of alkoxysilane and silazane with respect to 100 parts by mass of the silica raw material.

  In order to increase the immobilization rate of the silicone oil based on the carbon amount of the silica fine particles, it is necessary to chemically immobilize the silicone oil on the surface of the silica raw material in the process of obtaining the silica fine particles. For that purpose, a method of performing a heat treatment for the reaction of silicone oil in the process of obtaining silica fine particles can be suitably exemplified. The heat treatment temperature is preferably 100 ° C. or higher. The higher the heat treatment temperature, the higher the immobilization rate. This heat treatment step is preferably performed immediately after the silicone oil treatment, but when the crushing treatment is performed, the heat treatment step may be performed after the crushing treatment step.

  The silica fine particles used in the present invention preferably have an apparent density of 15 g / L or more and 50 g / L or less. The apparent density of the silica fine particles being in the above range indicates that the silica fine particles are difficult to be densely packed and exist with a lot of air between the fine particles, and the apparent density is very low. For this reason, even in the toner, since the toner is less likely to be clogged closely, the deterioration rate can be significantly reduced. A more preferable range is 18 g / L or more and 45 g / L or less.

  Means for controlling the apparent density of the silica fine particles within the above range include adjusting the particle size of the silica raw material used for the silica fine particles, the presence / absence and the strength of the above-mentioned crushing treatment, the amount of silicone oil treated, and the like. It is done. By reducing the particle size of the silica raw material, the BET specific surface area of the silica fine particles to be obtained becomes large and a large amount of air can be interposed, so that the apparent density can be reduced. Further, by performing the crushing treatment, relatively large secondary particles contained in the silica fine particles can be loosened into relatively small secondary particles, and the apparent density can be reduced.

The silica base material used in the present invention has a specific surface area (BET specific surface area) measured by a BET method by nitrogen adsorption of 130 m ² / g or more and 330 m ² / g or less in order to impart good fluidity to the toner. Is preferred. In this range, the fluidity and chargeability imparted to the toner can be easily secured even after long-term use. The BET specific surface area of the silica base material is more preferably 200 m ² / g or more and 320 m ² / g or less.
The specific surface area (BET specific surface area) measured by the BET method by nitrogen adsorption is measured according to JIS Z8830 (2001). As a measuring device, an “automatic specific surface area / pore distribution measuring device TriStar 3000 (manufactured by Shimadzu Corporation)” which employs a gas adsorption method by a constant volume method as a measuring method is used.
Further, the number average particle size of the primary particles of the silica raw material used in the present invention is preferably 3 nm or more and 50 nm or less, and more preferably 5 nm or more and 40 nm or less.

  In addition to the silica fine particles, particles having a primary particle number average particle diameter (D1) of 80 nm or more and 3 μm or less may be added to the toner according to the present invention. For example, lubricants such as fluororesin powder, zinc stearate powder and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder and strontium titanate powder; spacer particles such as silica affect the effect of the present invention. A small amount can be used.

In particular, the toner according to the present invention contains fine particles of an alkaline earth metal titanate such as strontium titanate fine particles (hereinafter also referred to as ST fine particles), and the number average particle size of the primary particles is in a specific range. It is preferable that
As a result, the effect of suppressing the charge-up of the toner can be sufficiently exerted, and the adhesion of the toner to the member can be further reduced.

  As a result, for example, even when an image is formed after the developing sleeve is reduced in diameter and left to stand after long-term durability use in a low-temperature and low-humidity environment, the entire toner can be appropriately charged, and the toner adherence can be improved. There is a tendency that not only the reduction but also the transfer residual toner is reduced.

In the alkaline earth metal titanate particles added in the present invention, the number average particle diameter (D1) of the primary particles is preferably 60 nm or more and 200 nm or less, and more preferably 80 nm or more and 150 nm or less. . By being in this range, fine particles of alkaline earth metal titanate are in the form of primary particles and easily adhere to the surface of the toner particles, so that the embedding rate of the external additive can be easily controlled. Moreover, since it is difficult to detach in the durability use test, a charge-up suppressing effect is easily obtained.
When the thickness is less than 60 nm, the effect of charge adjustment as a microcarrier cannot be sufficiently obtained. On the other hand, when it is larger than 200 nm, it is easy to detach from the toner surface, and it is difficult to obtain a sufficient charge-up suppressing effect.

Preferable examples of the alkaline earth metal titanate fine particles include beryllium titanate fine particles, magnesium titanate fine particles, calcium titanate fine particles, strontium titanate fine particles, barium titanate fine particles, and radium titanate fine particles. Among these, strontium titanate is preferable in that it has an excellent toner charge-up suppressing effect.
While the binder resin according to the present invention tends to have a high negative chargeability, such an alkaline earth metal titanate has a relatively weak positive chargeability, and therefore is effective in suppressing the charge-up of the toner. Are better.

Further, when strontium titanate fine particles are used as the fine particles of alkaline earth metal titanate, titanium having a perovskite type crystal structure, more preferably a cubic particle shape and / or a rectangular parallelepiped particle shape, is more preferable. Strontium acid fine particles are used.
Strontium titanate fine particles having a cubic particle shape and / or a rectangular parallelepiped particle shape and having a perovskite crystal structure are produced mainly in an aqueous medium without going through a sintering step. For this reason, since it is easy to control to a uniform particle size, it is preferably used in the present invention. That is, the alkaline earth metal titanate fine particles that can be easily controlled to have a uniform particle size can adhere to the toner more uniformly and remain on the surface of the toner particles in a state where it is difficult to separate.
To confirm that the crystal structure of the alkaline earth metal titanate fine particles is of the perovskite type (face-centered cubic lattice composed of three different elements), confirm by X-ray diffraction measurement. be able to.

In the present invention, the surface of fine particles of alkaline earth metal titanate is preferably treated in consideration of development characteristics and the ability to control the triboelectric charge characteristics and the triboelectric charge amount depending on the environment.
Examples of the surface treating agent include treating agents such as fatty acids, fatty acid metal salts, and organosilane compounds.
By performing surface treatment, for example, in the case of a coupling agent that is a compound having a hydrophilic group and a hydrophobic group, the hydrophilic group side covers the surface of fine particles of alkaline earth metal titanate, so the hydrophobic group side becomes the outside. The alkaline earth metal titanate fine particles are hydrophobized. By doing so, fluctuations in the triboelectric charge amount due to the environment can be suppressed. Further, the coupling agent into which a functional group such as an amino group or fluorine is introduced can easily control the triboelectric charge amount, and the effects of the present invention can be more easily exhibited.
In the case of the surface treatment agent as described above, the shape of the alkaline earth metal titanate fine particles is hardly changed due to the surface treatment at the molecular level, and the scraping power by a substantially cubic or rectangular parallelepiped shape. Is more preferable.

Examples of the surface treatment agent include titanate-based, aluminum-based, and silane-based coupling agents. Examples of the fatty acid metal salt include zinc stearate, sodium stearate, calcium stearate, zinc laurate, aluminum stearate, magnesium stearate, and the like, and the same effect can be obtained with stearic acid which is a fatty acid.
The treatment method is a wet method in which a surface treatment agent or the like to be treated is dissolved and dispersed in a solvent, fine particles of an alkaline earth metal titanate are added therein, the solvent is removed while stirring, and the treatment is performed. Can be mentioned. In addition, a coupling method, a dry method in which fine particles of a fatty acid metal salt and an alkaline earth metal titanate are directly mixed and agitation is performed may be used.
Further, it is not necessary to completely treat and coat the alkaline earth metal titanate fine particles for the surface treatment, and the alkaline earth metal titanate fine particles may be exposed as long as the effect is obtained. . That is, the surface treatment may be formed discontinuously.

Further, the adhesion rate of the alkaline earth metal titanate fine particles is preferably 50% or more and 90% or less, and more preferably 60% or more and 80% or less. When the adhesion rate is within this range, an appropriate action as a microcarrier and a charge-up suppressing effect can be exhibited.
When the fixing rate exceeds 90%, the effect as a microcarrier tends to be insufficient, and the whole toner tends to be hardly charged uniformly.
When the fixing rate is less than 50%, the effect of suppressing the charge-up tends to be insufficient, and the effect of reducing the adhesion force with the member tends to be reduced.

Further, in the present invention, in order to sufficiently exhibit the above-described action as a microcarrier and the effect of suppressing charge-up, 0.1 parts by mass or more of alkaline earth metal titanate fine particles per 100 parts by mass of toner particles It is preferable to contain 1.0 mass part or less. More preferably, it is 0.1 to 0.6 parts by mass.
Even if a large amount of alkaline earth metal titanate particles are contained, if the fixing rate is low, it is difficult to exert a sufficient charge-up suppressing effect.
As a means for controlling the adhesion rate of the alkaline earth metal titanate fine particles within the above-mentioned range, adjustment of power and treatment time during external addition mixing treatment may be mentioned. The fixing rate can be lowered by reducing the power during the external addition mixing process or shortening the processing time. Further, the fixing rate can be increased by increasing the power during the external addition mixing process or by increasing the processing time.

The toner according to the present invention contains a colorant.
Examples of the colorant preferably used in the present invention include the following.
Examples of organic pigments or organic dyes as cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

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

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

Examples of the black colorant include carbon black, the yellow colorant, the magenta colorant, and the one that is toned in black using a cyan colorant.
When using a colorant, it is preferably used by adding 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer or binder resin.

The toner according to the present invention may contain a magnetic material. In the present invention, the magnetic material can also serve as a colorant.
The magnetic material used in the present invention is mainly composed of triiron tetroxide or γ-iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, and aluminum. The shape of the magnetic material includes a polyhedron, octahedron, hexahedron, sphere, needle shape, flake shape, etc., but a polyhedron, octahedron, hexahedron, sphere and the like having a small anisotropy can reduce the image density. It is preferable in terms of enhancement. The content of the magnetic substance in the present invention is preferably 50 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer or binder resin.

The toner according to the present invention preferably contains a wax. The wax preferably includes a hydrocarbon wax. Other waxes include the following. Amide waxes, higher fatty acids, long chain alcohols, ketone waxes, ester waxes, and derivatives such as these graft compounds and block compounds. If necessary, two or more kinds of waxes may be used in combination. Among these, when the hydrocarbon wax by the Fischer-Tropsch method is used, the high temperature offset resistance can be kept good while maintaining the developability well for a long time. These hydrocarbon waxes may contain an antioxidant within a range that does not affect the chargeability of the toner.
The content of the wax is preferably 4.0 parts by mass or more and 30.0 parts by mass or less, and preferably 16.0 parts by mass or more and 28.0 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferred.

In the toner according to the present invention, a charge control agent can be contained in the toner particles as necessary. By blending the charge control agent, the charge characteristics can be stabilized and the optimum triboelectric charge amount can be controlled according to the development system.
As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable. Further, when the toner particles are produced by a direct polymerization method, a charge control agent having a low polymerization inhibition property and substantially free from a solubilized product in an aqueous medium is particularly preferable.
The toner according to the present invention may contain these charge control agents alone or in combination of two or more.
The blending amount of the charge control agent is preferably 0.3 parts by mass or more and 10.0 parts by mass or less, and 0.5 parts by mass or more and 8. parts by mass or less with respect to 100 parts by mass of the polymerizable monomer or binder resin. More preferably, it is 0 parts by mass or less.

The toner according to the present invention preferably has a weight average particle diameter (D4) of 5.0 μm or more and 10.0 μm or less from the viewpoint of a balance between developability and fixability, and is 5.5 μm or more and 9.5 μm. The following is more preferable.
In the present invention, the average circularity of the toner particles is preferably 0.960 or more, and more preferably 0.970 or more. When the average circularity of the toner particles is 0.960 or more, the shape of the toner is a sphere or a shape close to this, and it is easy to obtain a uniform triboelectric chargeability with excellent fluidity. Therefore, it is preferable because high developability and transferability can be easily maintained even in the latter half of the durability.

Hereinafter, the toner manufacturing method according to the present invention will be exemplified, but the present invention is not limited thereto.
The toner production method may be any production method having a step of adjusting the number of silica fine particles treated with silicone oil, the carbon oil-based immobilization rate of silicone oil, and preferably the average circularity. In the other manufacturing process, it is not specifically limited, It can manufacture by a well-known method.

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

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

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

The toner particles used in the present invention are preferably those produced in an aqueous medium such as a dispersion polymerization method, an association aggregation method, a solution suspension method, and a suspension polymerization method. More preferably.
In the suspension polymerization method, first, a polymerizable monomer and a colorant, and, if necessary, other additives such as a polymerization initiator, a crosslinking agent and a charge control agent are uniformly dissolved or dispersed to be polymerizable. A monomer composition is obtained. Thereafter, the polymerizable monomer composition is dispersed in a continuous layer (for example, an aqueous phase) containing a dispersion stabilizer using a suitable stirrer, and then the polymerizable monomer in the polymerizable monomer composition is used. The toner is polymerized to obtain toner particles having a desired particle size. The toner particles obtained by this suspension polymerization method (hereinafter also referred to as “polymerized toner particles”) have a substantially spherical shape, and therefore satisfy a predetermined average circularity and have a charge amount of This is preferable because the distribution is relatively uniform.

In the production of the polymerized toner particles according to the present invention, known monomers can be used as the polymerizable monomer constituting the polymerizable monomer composition. Among these, styrene or a styrene derivative is preferably used alone or mixed with another polymerizable monomer from the viewpoint of the development characteristics and durability of the toner.
In the present invention, the polymerization initiator used in the suspension polymerization method preferably has a half-life of 0.5 hours or more and 30.0 hours or less during the polymerization reaction. Moreover, it is preferable that the addition amount of a polymerization initiator is 0.5 to 20.0 mass parts with respect to 100 mass parts of polymerizable monomers.
Specific examples of the polymerization initiator include azo or diazo polymerization initiators and peroxide polymerization initiators.

In the suspension polymerization method, a crosslinking agent may be added during the polymerization reaction, and a preferable addition amount is 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. .
Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used. For example, an aromatic divinyl compound, a carboxylic acid ester having two double bonds, a divinyl compound, and a compound having three or more vinyl groups are used alone or as a mixture of two or more.

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

After granulation, stirring may be performed using an ordinary stirrer to such an extent that the particle state is maintained and particle floating and sedimentation are prevented.
As the dispersion stabilizer, known surfactants, organic dispersants, or inorganic dispersants can be used. In particular, inorganic dispersants are less likely to produce harmful ultrafine powders, and because of their steric hindrance, dispersion stability is obtained, so even if the reaction temperature is changed, stability is not easily lost, and washing is easy and does not adversely affect the toner. Therefore, it can be preferably used. Examples of such inorganic dispersants include the following. Polycalcium phosphates such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, hydroxyapatite, carbonates such as calcium carbonate and magnesium carbonate, calcium metasuccinate, calcium sulfate, barium sulfate, etc. Inorganic compounds such as inorganic salts, calcium hydroxide, magnesium hydroxide and aluminum hydroxide.

These inorganic dispersants are preferably used in an amount of 0.20 parts by mass or more and 20.00 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. Moreover, the said dispersion stabilizer may be used independently and may use multiple types together. Furthermore, you may use together 0.0001 mass part or more and 0.1000 mass part or less surfactant with respect to 100 mass parts of polymerizable monomers.
The polymerization temperature in the polymerization reaction of the polymerizable monomer is set to a temperature of 40 ° C. or higher, generally 50 ° C. or higher and 90 ° C. or lower.
After the polymerization of the polymerizable monomer is completed, the obtained polymer particles are filtered, washed and dried by a known method to obtain toner particles. The toner according to the present invention is obtained by externally adding silica fine particles, which are inorganic fine particles, to the toner particles and adhering them to the surface of the toner particles.
It is also possible to add a classification step to the production process (before mixing the inorganic fine particles) to remove coarse powder and fine powder contained in the toner particles.
Next, it describes regarding the measuring method of each physical property which concerns on this invention.

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

As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.
Prior to measurement and analysis, the dedicated software is set as follows.
On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman The value obtained using Coulter Co.) 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, 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 Dispersion System Tetora 150” (manufactured by Nikka Ki Bios) having an electrical output of 120 W is prepared. About 3.3 liters of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 mL of Contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.

(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker (1) installed in the sample stand, the electrolytic solution (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set in the dedicated software is the weight average particle diameter (D4).

<Method for measuring number average particle diameter of primary particles of silica fine particles>
The number average particle diameter of the primary particles of the silica fine particles is calculated from the silica fine particle image on the toner surface photographed with Hitachi Ultra High Resolution Field Emission Scanning Electron Microscope S-4800 (Hitachi High-Technologies Corporation). The image capturing conditions of S-4800 are as follows.

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

(2) S-4800 observation condition setting The number average particle diameter of the primary particles of the silica fine particles is calculated using an image obtained by the reflected electron image observation of S-4800. Since the reflected electron image has less charge-up of the silica fine particles than the secondary electron image, the particle size of the silica fine particles can be accurately measured.
Liquid nitrogen is poured into the anti-contamination trap attached to the S-4800 mirror until it overflows, and is placed for 30 minutes. S-4800 “PCSTEM” is activated and flushing (cleaning of the FE chip as an electron source) is performed. Click the acceleration voltage display part of the control panel on the screen and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute. Confirm that the emission current by flashing is 20-40 μA. Insert the sample holder into the sample chamber of the S-4800 mirror. Press [Origin] on the control panel to move the sample holder to the observation position.

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

(3) Calculation of number average particle diameter (D1) of silica fine particles Drag within the magnification display section of the control panel to set the magnification to 100,000 (100k). The focus knob [COARSE] on the operation panel is rotated, and the aperture alignment is adjusted when the focus is achieved to some extent. Click [Align] on the control panel to display the alignment dialog and select [Beam]. The STIGMA / ALIGNMENT knob (X, Y) on the operation panel is rotated to move the displayed beam to the center of the concentric circle. Next, [Aperture] is selected, and the STIGMA / ALIGNMENT knobs (X, Y) are turned one by one to stop the movement of the image or adjust the movement to the minimum. Close the aperture dialog and focus with auto focus. Repeat this operation two more times to focus.
Thereafter, the particle diameter of at least 300 silica fine particles on the toner surface is measured to determine the average particle diameter. Here, since some silica fine particles exist as agglomerates, the number average particle size of primary particles of silica fine particles (by calculating the maximum diameter of those that can be confirmed as primary particles and arithmetically averaging the obtained maximum diameter ( D1) is obtained.

<Measuring method of average circularity of toner particles>
The average circularity of the toner particles is measured by a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.
A specific measurement method is as follows. First, about 20 mL of ion-exchanged water from which impure solids and the like are previously removed is placed in a glass container. 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 0.2 mL of a diluted solution obtained by diluting (made in ()) with ion-exchanged water about 3 times by mass is added. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by VervoCrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is put, and about 2 mL of the above-mentioned Contaminone N is added to this water tank.

  For the measurement, the above-mentioned flow type particle image analyzer equipped with “UPlanApro” (magnification 10 times, numerical aperture 0.40) as an objective lens is used, and the particle sheath “PSE-900A” (manufactured by Sysmex Corporation) is used as the sheath liquid. It was used. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, and 3,000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the circle equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles is obtained.

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

In the measurement, a flow type particle image measuring apparatus that has been calibrated by Sysmex Corporation and that has been issued a calibration certificate issued by Sysmex Corporation is used. Measurement is performed under the measurement and analysis conditions when the calibration certificate is received, except that the analysis particle diameter is limited to a circle equivalent diameter of 1.985 μm or more and less than 39.69 μm.
The measurement principle of the flow-type particle image measuring device “FPIA-3000” (manufactured by Sysmex Corporation) is to take a flowing particle as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is picked up by a CCD camera, and the picked-up image is image-processed at an image processing resolution of 512 × 512 pixels (0.37 × 0.37 μm per pixel), the contour of each particle image is extracted, and the particle image The projected area S, the peripheral length L, etc. are measured.

Next, the equivalent circle diameter and the circularity are obtained using the area S and the peripheral length L. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity is a value obtained by dividing the circumference of the circle obtained from the equivalent circle diameter by the circumference of the projected particle image. Defined and calculated by the following formula.
Circularity = 2 × (π × S) ^1/2 / L
When the particle image is circular, the circularity is 1.000. The greater the degree of irregularities on the outer periphery of the particle image, the smaller the circularity. After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is divided into 800, the arithmetic average value of the obtained circularity is calculated, and the value is defined as the average circularity.

<Method for measuring apparent density of silica fine particles>
The apparent density of the silica fine particles is measured by slowly adding a measurement sample placed on a paper to a 100 mL graduated cylinder to 100 mL, and obtaining the mass difference between the graduated cylinder before and after adding the sample by the following formula: calculate. When adding the sample to the graduated cylinder, be careful not to strike the paper.
Apparent density (g / L) = (mass (g) when 100 mL was added) /0.1

<Measurement method of true specific gravity of toner and silica fine particles>
The true specific gravity of the toner and silica fine particles was measured by a dry automatic densimeter autopycnometer (manufactured by Yuasa Ionics Co., Ltd.). The conditions are as follows.
Cell: SM cell (10 mL)
Sample amount: about 2.0 g (toner), 0.05 g (silica fine particles)
This measurement method measures the true specific gravity of a solid / liquid based on a gas phase substitution method. Similar to the liquid phase replacement method, it is based on Archimedes' principle, but since the gas (argon gas) is used as the replacement medium, the measurement accuracy of the micropores is high.

<Measurement method of carbon oil-based immobilization rate of silica fine particles>
(Extraction of free silicone oil)
(1) Put 0.50 g of silica fine particles and 40 mL of chloroform in a beaker and stir for 2 hours.
(2) Stop stirring and let stand for 12 hours.
(3) The sample is filtered and washed 3 times with 40 mL of chloroform.

(Measurement of carbon content)
The sample is burned at 1100 ° C. in an oxygen stream, and the amount of generated CO and CO ₂ is measured by IR absorbance to measure the amount of carbon in the sample. The carbon amount before and after extraction of the silicone oil is compared, and the immobilization rate based on the carbon amount of the silicone oil is calculated as follows.
(1) Place 0.40 g of sample in a cylindrical mold and press.
(2) 0.15 g of the pressed sample is precisely weighed, placed on a combustion board, and measured with Horiba EMA-110.
(3) [Carbon amount after silicone oil extraction] / [Carbon amount before silicone oil extraction] × 100 is defined as the immobilization rate based on the carbon amount of silicone oil.
When the surface treatment with silicone oil is performed after the hydrophobic treatment with a silane compound or the like, the amount of carbon in the sample is measured after the hydrophobic treatment with a silane compound or the like. Then, after the silicone oil treatment, the amount of carbon before and after the extraction of the silicone oil is compared, and the immobilization rate based on the amount of carbon derived from the silicone oil is calculated as follows.

(4) [Carbon amount after silicone oil extraction] / [(carbon amount before silicone oil extraction−carbon amount after hydrophobic treatment with silane compound)] × 100, To do.
On the other hand, when the hydrophobic treatment is performed with a silane compound or the like after the surface treatment with silicone oil, the immobilization rate based on the amount of carbon derived from silicone oil is calculated as follows.
(5) [(carbon amount after silicone oil extraction-carbon amount after hydrophobic treatment with silane compound)] / [carbon amount before silicone oil extraction] × 100, To do.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, all the parts and% of an Example and a comparative example are mass references | standards unless there is particular notice.

<Production example of magnetic material>
(Magnetic material 1)
The following materials were mixed in an aqueous ferrous sulfate solution to prepare an aqueous solution containing ferrous hydroxide.
1.00 to 1.10 equivalent of caustic soda solution with respect to iron element P ₂ O _{5 in an} amount of 0.12% by mass in terms of phosphorus element with respect to iron element
SiO _{2 in an} amount of 0.60% by mass in terms of silicon element with respect to iron element
The pH of the aqueous solution was 8.0, and an oxidation reaction was performed at 85 ° C. while blowing air to prepare a slurry liquid having seed crystals.

  Subsequently, the ferrous sulfate aqueous solution was added to this slurry liquid so that it might become 0.90 to 1.20 equivalent with respect to the original alkali amount (sodium component of caustic soda). Thereafter, the slurry liquid was maintained at pH 7.6, and an oxidation reaction was promoted while blowing air to obtain a slurry liquid containing magnetic iron oxide. After filtration and washing, the water-containing slurry was once taken out. At this time, a small amount of water-containing sample was collected and the water content was measured.

  Next, this water-containing sample was put into another aqueous medium without drying, stirred and redispersed with a pin mill while circulating the slurry, and the pH of the redispersed liquid was adjusted to about 4.8. Then, 1.7 parts by mass of n-hexyltrimethoxysilane coupling agent was added to 100 parts by mass of magnetic iron oxide while stirring (the amount of magnetic iron oxide was calculated as a value obtained by subtracting the water content from the water-containing sample). Hydrolysis was performed.

  Thereafter, the mixture was sufficiently stirred, and the dispersion was subjected to surface treatment at a pH of 8.6. The produced hydrophobic magnetic material is filtered with a filter press, washed with a large amount of water, dried at a temperature of 100 ° C. for 15 minutes, and then at a temperature of 90 ° C. for 30 minutes. A magnetic body 1 having a diameter of 0.23 μm was obtained.

(Magnetic material 2)
The slurry liquid was adjusted and the oxidation reaction was promoted in the same manner as in the production example of the magnetic body 1 except that SiO ₂ was mixed in an amount of 0.40% by mass in terms of silicon without adding phosphorus element. A slurry liquid containing magnetic iron oxide was obtained.
After filtration, washing and drying, the obtained particles were crushed to obtain a magnetic body 2 having a volume average particle size of 0.21 μm.

<Production example of polyester resin>
The following components were placed in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and reacted for 10 hours while distilling off the water produced at 230 ° C. under a nitrogen stream.
・ 75 parts by mass of bisphenol A propylene oxide 2 mol adduct 25 parts by mass of bisphenol A propylene oxide 3 mol adduct 110 parts by mass of terephthalic acid 0.25 part by mass of titanium catalyst (titanium dihydroxybis (triethanolamate))

  Next, the reaction was carried out under reduced pressure of 5 to 20 mmHg. When the acid value became 2 mgKOH / g or less, it was cooled to 180 ° C., 8 parts by mass of trimellitic anhydride was added, and the reaction was taken out for 2 hours under atmospheric pressure sealing, and then taken out. After cooling to 0, pulverization gave polyester resin 1. The obtained polyester resin 1 had a main peak molecular weight (Mp) of 95,000 as measured by gel permeation chromatography (GPC).

<Production Example 1 of Toner Particles>
After 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution was added to 720 parts by mass of ion-exchanged water and heated to 60 ° C., 67.7 parts by mass of 1.0 M CaCl ₂ aqueous solution was added to stabilize the dispersion. An aqueous medium containing the agent was obtained.

-Styrene 78.0 parts by mass-n-butyl acrylate 22.0 parts by mass-Divinylbenzene 0.6 parts by mass-Iron complex of monoazo dye (T-77: Hodogaya Chemical Co., Ltd.) 2.0 parts by mass Magnetic substance 1 90.0 parts by mass / Polyester resin 1 3.0 parts by mass The above formulation was uniformly dispersed and mixed using an attritor (manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain a polymerizable monomer composition. . The obtained polymerizable monomer composition was heated to 60 ° C., 15.0 parts by mass of Fischer-Tropsch wax (melting point: 74 ° C., number average molecular weight Mn: 500) was added and mixed, and after dissolution, the polymerization initiator was added. As a result, 7.0 parts by mass of dilauroyl peroxide was dissolved to obtain a toner composition.

The toner composition is charged into the aqueous medium, and stirred at 12,500 rpm for 12 minutes with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) in a N ₂ atmosphere at a temperature of 60 ° C., and granulated. did. Thereafter, the mixture was reacted at a temperature of 74 ° C. for 6 hours while stirring with a paddle stirring blade.
After completion of the reaction, the suspension was cooled, washed with hydrochloric acid, filtered and dried to obtain toner particles 1. The physical properties of the obtained toner particles 1 are shown in Table 1.

<Toner Particle Production Example 2>
In Toner Particle Production Example 1, toner particles 2 are produced in the same manner except that the rotational speed of TK homomixer (made by Tokushu Kika Kogyo Co., Ltd.) is decreased from 12,500 rpm to 9,500 rpm. did. The physical properties of the obtained toner particles 2 are shown in Table 1.

<Production Example 3 of Toner Particles>
-Styrene acrylic copolymer 100 parts by mass (mass ratio of styrene and n-butyl acrylate is 78.0: 22.0, main peak molecular weight Mp is 10,000)
• 90 parts by mass of magnetic substance 2 • iron complex of monoazo dye (T-77: Hodogaya Chemical Co., Ltd.) 2.0 parts by mass • 4 parts by mass of Fischer-Tropsch wax (melting point: 74 ° C., number average molecular weight Mn: 500 )

  The mixture was premixed with a Henschel mixer, melt-kneaded with a biaxial extruder heated to 110 ° C., and the cooled kneaded product was coarsely pulverized with a hammer mill to obtain a coarsely pulverized toner product. The obtained coarsely pulverized product was a mechanical pulverizer turbo mill (manufactured by Turbo Kogyo Co., Ltd .; coated with chromium alloy plating containing chromium carbide on the rotor and stator surfaces (plating thickness 150 μm, surface hardness HV1050)). Was mechanically pulverized (pulverized). The finely pulverized product was classified and removed at the same time by a multi-division classifier (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect to obtain toner particles A.

The toner particles A were subjected to a thermal spheronization process. The thermal spheronization treatment was performed using a surfing system (manufactured by Nippon Pneumatic Co., Ltd.). The operating conditions of the thermal spheronizer were as follows.
Feed amount = 5 kg / hr,
Hot air temperature C = 260 ° C., hot air flow rate = 6 m ³ / min,
Cold air temperature E = 5 ° C., cold air flow rate = 4 m ³ / min, cold air absolute water content = 3 g / m ³ ,
Blower air volume = 20 m ³ / min, injection air flow rate = 1 m ³ / min, diffusion air = 0.3 m ³ / min.
Toner particles 3 were obtained by the surface treatment under the above conditions. The physical properties of the obtained toner particles 3 are shown in Table 1.
The true density of toner particles 1 to 3 was measured and found to be 1.6 g / cm ³ .

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

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

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

  100 parts of strontium titanate fine particles were added to a sodium stearate aqueous solution (7 parts of sodium stearate and 100 parts of water) which is a fatty acid metal salt. While stirring, an aqueous aluminum sulfate solution was dropped, and aluminum stearate was deposited and adsorbed on the surface of strontium titanate fine particles to prepare strontium titanate treated with stearic acid. Moreover, the particle size was increased by increasing the reaction time after the slurry was heated to 90 ° C., and strontium titanate fine particles 1 to 3 having a target particle size were prepared. Table 2 shows the physical properties of the strontium titanate fine particles 1 to 3.

<Production Example 4 of Strontium Titanate Fine Particles>
600 g of strontium carbonate and 320 g of titanium oxide were dry mixed in a ball mill for 8 hours and then filtered and dried. This mixture was molded at a pressure of 5 kg / cm ² and calcined at a temperature of 1100 ° C. for 8 hours. Thereafter, the resultant was mechanically pulverized to obtain strontium titanate fine particles 4 having a number average particle diameter of 500 μm. Table 2 shows the physical properties of the strontium titanate fine particles 4.

<Production Example of Toner 1>
The toner particles 1 obtained in the production example of the toner particles 1 were subjected to external addition mixing treatment.
As an external device, Mitsui Henschel mixer FM10C (manufactured by Mitsui Miike Chemical Co., Ltd.) was used.
For 100 parts by mass of toner particles 1,
0.40 parts by mass of silica fine particles 1 (number average particle size of primary particles of silica raw material: 7 nm, number average particle size of primary particles of treated silica fine particles: 8 nm) shown in Table 3;
0.30 part by mass of the strontium titanate fine particles 1 shown in Table 2 was put into a Henschel mixer.

After the addition, an external addition mixing process was performed at 4,000 rpm for 3 minutes, 0.30 parts by mass of silica fine particles 1 were further added, and an external addition mixing process was performed at 4,000 rpm for 2 minutes.
After the external addition and mixing treatment, coarse particles and the like were removed with a circular vibration sieve equipped with a screen having a diameter of 500 mm and an opening of 75 μm, to obtain Example Toner 1. The toner 1 for Example was magnified and observed with a scanning electron microscope, and the number average particle diameter of primary particles of silica fine particles on the toner surface was measured and found to be 8 nm. Table 4 shows the external addition conditions and physical properties of Toner 1.

<Production Example of Toners 2 to 22>
Toners 1 to 22 were produced in the same manner as in the production example of Toner 1 except that the external additives shown in Table 2 or 3 were changed to the toner particles and external addition conditions shown in Table 4. Table 4 shows the physical properties of the obtained toners 2 to 22.

<Production example of resin particle 1>
An aqueous mixed solution composed of 4,000 parts by mass of ion-exchanged water and 9 parts by mass of colloidal silica and 0.15 parts by mass of polyvinylpyrrolidone as a dispersion stabilizer was prepared. Next, an oily mixed solution composed of the following materials was prepared.
Polymerizable monomer: Acrylonitrile 50 parts by weight Polymerizable monomer: Methacrylonitrile 45 parts by weight Polymerizable monomer: Methyl methacrylate 5 parts by weight Inclusion material: Normal hexane 12.5 parts by weight Polymerization initiator: Dicumyl Peroxide 0.75 parts by mass The 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 polymerization reaction vessel purged with nitrogen, and reacted at a temperature of 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 the temperature of 80 degreeC for 5 hours. Resin particles 1 were obtained by crushing and classifying the obtained resin particles with a sonic classifier.
The physical properties of the obtained resin particles 1 are shown in Table 1.

<Production example of resin particle 2>
Resin particles 2 were produced in the same manner as in the production example of resin particles 1 except that the classification conditions were changed. Table 5 shows the physical properties of the obtained resin particles 2.

<Production Example of Resin Particle 3>
Resin particles 3 are obtained by preparing and classifying resin particles in the same manner as in the production example of resin particles 1 except that the polymerizable monomer is changed to 80 parts by mass of acrylonitrile and 20 parts by mass of methacrylonitrile. It was. Table 5 shows the physical properties of the obtained resin particles 3.

<Production example of resin particle 4>
Resin particles are produced and classified in the same manner as in the production example of resin particles 1 except that the amount of colloidal silica added is changed to 4.5 parts by mass and the polymerizable monomer is changed to 100 parts by mass of acrylonitrile. Thus, resin particles 4 were obtained. Table 5 shows the physical properties of the obtained resin particles 4.

<Production example of resin particle 5>
Resin particles 5 were prepared by preparing and classifying resin particles in the same manner as in the production example of resin particles 1 except that the polymerizable monomer was changed to 100 parts by mass of methyl methacrylate and the stirring during polymerization was changed to 250 rpm. Got. Table 5 shows the physical properties of the obtained resin particles 5.

<Production Example of Resin Particle 6>
Resin particles were produced in the same manner as in the production example of the resin particles 4 except that the polymerizable monomer was changed to 100 parts by mass of polybutadiene and the stirring during polymerization was changed to 300 rpm. Table 5 shows the physical properties of the obtained resin particles 6.

[Measurement of volume average particle diameter of resin particles]
The volume average particle size of the resin particles was measured with a Coulter LS-230 type particle size distribution meter (trade name, manufactured by 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 minute to 3 minutes with an ultrasonic disperser to prepare a test sample solution, and the test sample solution was gradually added to the measurement system of the measurement apparatus. And it measured by adjusting the test sample density | concentration in a measurement system so that PIDS (Polarization Intensity Differential Scattering) on the screen of an apparatus may be 45% or more and 55% or less. The volume average particle diameter was calculated from the obtained volume distribution.

<Example of production of sheet-like composition 1>
The obtained resin particles 1 were heated and decompressed at 100 ° C. to remove the encapsulated material, thereby obtaining a resin composition. Thereafter, the resin composition was filled in a mold (diameter 70 mm, depth 500 μm) heated to 160 ° C., and pressurized at a pressure of 10 MPa to obtain a sheet-like composition 1.
Table 6 shows the oxygen permeability of the obtained sheet-like composition 1.

<Production example of sheet-like compositions 2 to 5>
By using the resin particles 3 to 6, sheet-like compositions 2 to 5 were obtained by the same method as in the production example of the sheet-like composition 1. Table 6 shows the oxygen permeability of the sheet-like compositions 2 to 5.

[Measurement of oxygen gas gas permeability of resin particle shell]
The oxygen gas permeability of the resin particle shell material was measured by separately preparing a measurement sheet. In addition, about the preparation method of the sheet | seat for a measurement, it explained in full detail in the manufacture example of the said resin particle.
The oxygen gas permeability using the sheet was measured under the following conditions based on the differential pressure method according to JISK7126.
Measuring machine: Gas permeability measuring device M-C3 type (manufactured by Toyo Seiki Seisakusho)
Gas used: Oxygen gas equivalent to JIS K1101 Measurement temperature: 23 ± 0.5 ° C
Test pressure: 760mmHg
Transmission area: 38.46 cm ² (70 mm diameter)
Sample thickness: 500 μm

First, the produced measurement sheet was mounted on a permeation cell and fixed with a uniform pressure so as not to cause air leakage.
First, the low pressure side and the high pressure side are evacuated, the low pressure side exhaust is stopped, and the vacuum is maintained. Thereafter, oxygen gas is introduced into the high pressure side at 1 atm, and the pressure on the high pressure side at this time is set to Pu. After the pressure on the low-pressure side began to rise and the permeation of oxygen gas was confirmed, a permeation curve was drawn, and measurement was performed until a straight line portion showing a steady state of permeation was confirmed.
After the measurement, the slope of the permeation curve was d _p / _dt, and the oxygen gas permeability GTR was calculated using equation (9).

(Vc: low pressure side volume, T: test temperature, Pu: differential pressure of supply gas,
A: permeation area, d _p / d _t : pressure change on the low pressure side per unit time, R: gas constant)

<Production Example of Conductive Rubber Composition 1>
The following 4 components were added to 100 parts by mass of acrylonitrile butadiene rubber (NBR) (trade name: N230SV, manufactured by JSR) and kneaded for 15 minutes in a closed mixer adjusted to 50 ° C.
Carbon black (trade name: Toka Black # 7360SB, manufactured by Tokai Carbon Co., Ltd.): 48 parts by mass Zinc oxide (trade name: 2 types of zinc white, manufactured by Sakai Chemical Industry Co., Ltd.): 5 parts by mass Zinc (trade name: SZ-2000, manufactured by Sakai Chemical Industry Co., Ltd.): 1 part by mass. Calcium carbonate (trade name: Nanox # 30, manufactured by Maruo Calcium Co., Ltd.) 20 parts by mass. 1.2 parts by mass of sulfur as a vulcanizing agent and 4.5 parts by mass of tetrabenzylthiuram disulfide (TBzTD) (trade name: Parkasit TBzTD, manufactured by Frekins) were added as a vulcanization accelerator. 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.
The composition of the obtained conductive rubber composition 1 is shown in Table 7.

<Production Example of Conductive Rubber Composition 2>
A conductive rubber composition 2 was obtained in the same manner as in the production example of the conductive rubber composition 1 except that the resin particles 1 were changed to the resin particles 2 in the production example of the conductive rubber composition 1.
The composition of the obtained conductive rubber composition 2 is shown in Table 7.

<Production Example of Conductive Rubber Composition 3>
A conductive rubber composition 3 was obtained in the same manner as in the production example of the conductive rubber composition 1 except that the resin particles 1 were changed to the resin particles 3 in the production example of the conductive rubber composition 1.
Table 7 shows the composition of the obtained conductive rubber composition 3.

<Production Example of Conductive Rubber Composition 4>
A conductive rubber composition 4 was obtained in the same manner as in the production example of the conductive rubber composition 1 except that the resin particles 1 were changed to the resin particles 4 in the production example of the conductive rubber composition 1.
The composition of the obtained conductive rubber composition 4 is shown in Table 7.

<Production Example of Conductive Rubber Composition 5>
A conductive rubber composition 5 was obtained in the same manner as in the production example of the conductive rubber composition 1 except that the resin particles 1 were changed to the resin particles 5 in the production example of the conductive rubber composition 1.
Table 7 shows the composition of the obtained conductive rubber composition 5.

<Production Example of Conductive Rubber Composition 6>
The following 5 components were added to 100 parts by mass of styrene butadiene rubber (SBR) (trade name: Toughden 2003, manufactured by Asahi Kasei Co., Ltd.), and kneaded for 15 minutes with a closed mixer adjusted to 80 ° C.
Zinc oxide (similar to Production Example 1): 5 parts by mass Zinc stearate (similar to Production Example 1): 1 part by mass Carbon black (trade name: Ketjen Black EC600JD, manufactured by Lion): 8 parts by mass Carbon black (trade name: Seast 5, manufactured by Tokai Carbon Co., Ltd.): 40 parts by mass / calcium carbonate (similar to Production Example 1): 15 parts by mass

The following 4 components were added to this.
・ 12 parts by mass of resin particles 1 ・ 1 part by mass of sulfur as a vulcanizing agent ・ Dibenzothiazyl sulfide (DM) as a vulcanization accelerator (trade name: Noxeller TS, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1 part by mass Tetramethylthiuram monosulfide (TS) (trade name: Noxeller TS, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1 part by mass Next, kneaded for 10 minutes in a two-roll machine cooled to a temperature of 25 ° C., and conductive rubber Composition 6 was obtained.
The composition of the obtained conductive rubber composition 6 is shown in Table 7.

<Production Example of Conductive Rubber Composition 7>
A conductive rubber composition 7 was obtained in the same manner as in the production example of the conductive rubber composition 1 except that the resin particles 1 were changed to the resin particles 6 in the production example of the conductive rubber composition 1.
The composition of the obtained conductive rubber composition 7 is shown in Table 7.

<Production example of charging members T1 to T32>
[Charging member T1]
[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.

[Formation of conductive elastic layer]
Using an extrusion molding apparatus equipped with a crosshead, the conductive rubber composition 1 was coated in a cylindrical shape on the same axis with the conductive substrate as the central axis. The thickness of the coated conductive rubber composition 1 was adjusted to 1.75 mm.
The extruded roller was vulcanized in a hot air oven at a temperature of 160 ° C. for 1 hour, and then the end of the conductive elastic layer was removed to a length of 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. The thickness of the conductive elastic layer was adjusted to 1.5 mm. The crown amount of this roller (the outer diameter difference between the central portion and a position 90 mm away from the central portion) was 120 μm.

After polishing, a charging member T1 was obtained by performing post-heating treatment at 210 ° C. for 1 hour in a hot air oven.
This charging member T1 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 8 and 9 show the evaluation results of the obtained charging member T1.

<Method for evaluating charging member>
[1. Measurement of surface roughness Rzjis and average unevenness Sm of charging member]
It measures according to the specification of JISB0601-1994 surface roughness, and measures it using a surface roughness measuring device (brand name: SE-3500, Co., Ltd. product made from Kosaka Laboratory). Rzjis and Sm are the average values obtained by randomly measuring the surface of the charging member T1 at six locations. The cut-off value is 0.8 mm, and the evaluation length is 8 mm.

[2. Measuring the shape of bowl-shaped resin particles)
The measurement location is the roller circumferential direction at the central portion in the longitudinal direction of the roller, the location 45 mm away from the central portion in the direction of both ends, and the location 5 mm away from the center portion in the direction of both ends. A total of 10 locations of 2 locations (phase 0 ° and 180 °). 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. To do. The obtained cross-sectional images are combined to calculate a three-dimensional image of the bowl-shaped resin particles. From the stereoscopic image, the maximum diameter 55 shown in FIG. 6 and the minimum diameter 63 of the opening diameter shown in FIG. 7 are calculated. Further, from the three-dimensional image, the thickness of the shell of the bowl-shaped resin particles is measured at any five points of the bowl-shaped resin particles. Such measurement is carried out for 10 resin particles in the field of view, and the average value of the total 100 measured values obtained is calculated, and these are respectively calculated as “maximum diameter”, “minimum diameter of aperture” 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 It was confirmed to be substantially uniform.

[3. Measurement of the height difference between the top of the protrusion on the surface of the charging member and the bottom of the recess]
The surface of the charging member T1 is 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 is obtained by scanning the laser in the XY plane in the field of view, and further, the focal point is moved in the Z direction, and the above scanning is repeated to obtain three-dimensional image data. As a result, first, it is confirmed that a concave portion derived from the opening of the bowl-shaped resin particle and a convex portion derived from the edge of the opening of the bowl-shaped resin particle are provided. Further, a height difference 54 between the vertex 53 of the convex part and the bottom part 52 of the concave part is calculated. Such an operation is performed for two bowl-shaped resin particles in the field of view. Then, the same measurement is performed at 50 points in the longitudinal direction of the charging member T1, and the average value of the total 100 resin particles obtained is calculated.

[4. Measurement of surface hardness of charging member]
Based on ISO14577, it was measured using Picodenter HM500 (trade name, manufactured by Fisher Instrument Co., Ltd.). A square pyramidal diamond was used as the indenter. The measurement was performed for the central portion in the longitudinal direction, and the measurement locations were the two locations of the binder portion (non-bowl particle portion) and the bowl particle portion. Measurement conditions are as follows.
・ Maximum indentation depth = 100μm
Indentation time = 20 seconds The Martens hardness at a position where the depth = 20 μm was measured, the Martens hardness of the binder part (non-bowl particle part) was M1, and the Martens hardness of the bowl particle part was M2. In measuring the bowl particle portion, the indenter was pressed against the center of the bowl particle. Each measurement was performed at 10 points, and the average value was used.
M (= M2 / M1) was calculated by dividing M2 by M1 from M2 and M1 calculated from the 10-point average.

[5. Electric resistance of charging member]
FIG. 4 shows an apparatus for measuring the electrical resistance value of the charging member. A load is applied to both ends of the conductive substrate 33 using the bearings 32 to bring the charging member T1 into contact with the columnar metal 31 having the same curvature as that of the electrophotographic photosensitive member in parallel. In this state, the cylindrical metal 31 is rotated by a motor (not shown), and a DC voltage of −200 V is applied from the stabilizing power supply 35 while the charging member T1 that is in contact with the rotation is driven. The current flowing at this time is measured by an ammeter 36, and the electric resistance value of the charging member is calculated. The load is 4.9 N each, the diameter of the metal cylinder is 30 mm, and the rotation of the metal cylinder is a peripheral speed of 45 mm / second.
In the measurement, the charging member is 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 is performed using a measuring device placed in the environment.

[6. Measurement of the average contact area per contact portion between the charging member and the glass plate when the charging member is pressed against the glass plate]
It measured using the jig which has a mechanism shown in FIG.
The stage 81 can set the charging member T1 and can be moved up and down. The glass plate 82 is 20 mm square (vertical 20 mm, horizontal 20 mm) and has a thickness of 2 mm, and is disposed above the stage 81. The charging member T1 set on the stage 81 can be pressed against the glass plate 82 by moving the stage 81 upward. Further, the load applied when the charging member T1 is pressed against the glass plate 82 can be measured by a load meter 84 set on the upper portion of the stage 83 that fixes the glass plate.

The charging member T1 is pressed against a 20 mm square glass plate with a load of 100 g, and the contact surface (the lower surface of the glass) between the charging member T1 and the glass plate is as follows from the side opposite to the contact surface (the upper surface side of the glass). The video microscope was used for observation.
Video microscope (Product name: DIGITAL MICROSCOPE VHX-500, manufactured by Keyence Corporation)

The observation magnification is 200 times, and only the contact point between the charging member T1 and the glass plate is extracted using image analysis software (ImageProPlus (registered trademark): manufactured by Adobe System), and binarization processing is performed. The average contact area S1 per part was calculated.
Then, the load concerning a glass plate was changed into 500 g, the average contact area S5 per contact part was computed with the same method, and S shown by said Formula (1) was computed.

[7. Spatial average distance of the space formed between the charging member and the glass plate when the charging member is pressed against the glass plate]
Similar to the above measurement, measurement was performed using a jig having the mechanism shown in FIG.
The charging member T1 is pressed against a 20 mm square glass plate with a load of 100 g, and the surface shape of the contact surface (the lower surface of the glass) between the charging member T1 and the glass plate is opposite to the contact surface (the upper surface side of the glass). ) From the following one-shot 3D measurement macroscope.
One-shot 3D measurement macroscope (trade name: VR-3000, manufactured by Keyence Corporation)
The observation magnification was 160 times. From the shape measurement, the nip width L μm is calculated from the cross-sectional profile, and the space volume V1 of the space formed between the charging member T1 and the glass surface in the area of the nip width L μm × the maximum longitudinal length Aμm at the observation magnification. Was determined from volume measurements. Then, the average space distance d1 of the said space was computed by following formula (10).

  Thereafter, the load applied to the glass plate was changed to 500 g, and the average spatial distance d5 of the space formed between the charging member T1 and the glass surface was calculated by the same method. Using the average spatial distances d1 and d5 calculated in this way, d represented by the above formula (2) was calculated.

[Charging member T2]
A charging member T2 was produced in the same manner as the charging member T1, except that the vulcanization temperature was changed to 180 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T2.

[Charging member T3]
A charging member T2 was produced in the same manner as the charging member T1, except that the vulcanization temperature was changed to 200 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T3.

[Charging member T4]
A charging member T4 was produced in the same manner as the charging member T2, except that the conductive rubber composition 1 was changed to the conductive rubber composition 2. Tables 8 and 9 show the evaluation results of the obtained charging member T4.

[Charging member T5]
A charging member T5 was produced in the same manner as the charging member T1, except that the conductive rubber composition 1 was changed to the conductive rubber composition 3 and the heating temperature after polishing was changed to 190 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T5.

[Charging member T6]
A charging member T6 was produced in the same manner as the charging member T1, except that the conductive rubber composition 1 was changed to the conductive rubber composition 4. Tables 8 and 9 show the evaluation results of the obtained charging member T6.

[Charging member T7]
A charging member T7 was produced in the same manner as the charging member T1, except that the conductive rubber composition 1 was changed to the conductive rubber composition 5 and the heating temperature after polishing was changed to 190 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T7.

[Charging member T8]
A charging member T8 was produced in the same manner as the charging member T1, except that the conductive rubber composition 1 was changed to the conductive rubber composition 6. Tables 8 and 9 show the evaluation results of the obtained charging member T8.

[Charging member T9]
A charging member T9 was produced in the same manner as the charging member T1, except that the conductive rubber composition 1 was changed to the conductive rubber composition 7 and the heating temperature after polishing was changed to 170 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T9.

[Charging member T10]
A charging member T10 was produced in the same manner as the charging member T9 except that the heating temperature after polishing was changed to 210 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T10.

[Charging member T11]
A charging member T11 was produced in the same manner as the charging member T9 except that the heating temperature after polishing was changed to 230 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T11.

[Charging member T12]
A charging member T12 was produced in the same manner as the charging member T9 except that the heating temperature after polishing was changed to 240 ° C. Tables 8 and 9 show the evaluation results of the obtained charging member T12.

<Example 1>
[Evaluation 1 White defect image defect]
As an image forming apparatus, LBP-6300 (manufactured by Canon Inc.) was used, and the process speed was modified to about 1.5 times 300 mm / second.
The cartridge is mounted with a developing sleeve from a diameter of 14 mm to a diameter of 10 mm, the charging member T1 as a charging member, and the photosensitive member from a 24 mm diameter to a small diameter photosensitive member having a diameter of 18 mm. And mounted on each cartridge. Further, a modified cartridge in which the volume of the toner filling portion is 1.2 times and the contact pressure of the cleaning blade is changed to about half of 3 kgf / m was used.

In an image forming apparatus equipped with a small-diameter developing sleeve, by increasing the process speed, as described above, a part of the toner is charged up, and the toner tends to be unevenly charged. As a result, not only the transfer residual toner tends to increase, but also the adhesion to the charging member tends to be promoted, so that it is possible to strictly evaluate white spot-like image defects.
Using this modified machine, the toner 1 was used, and an image printing test was performed in a low temperature and low humidity environment (temperature 0 ° C., relative humidity 10%). A test for printing 8,000 sheets of horizontal lines with a printing rate of 1% in a two-sheet intermittent mode was performed.

By performing an image printing test in a low-temperature and low-humidity environment (temperature 0 ° C., relative humidity 10%), the toner is more easily charged up and strict evaluation is possible.
After outputting 8,000 sheets, a solid black image was output, and white spot-like image defects were visually determined. As a result, no white spot-like image defect was observed, and a good image was obtained.
Hereinafter, the judgment criteria will be described.

A: No white spot-like image defect is observed.
B: Slight white spot-like image defects are observed.
C: A white spot-like image defect occurs corresponding to the rotation pitch of the photoreceptor.
D: White spot-like image defects are conspicuous.

[Evaluation 2 Black defect image defect]
Using the modified machine used in Evaluation 1, the toner 1 was used, and an image printing test was performed in a low temperature and low humidity environment (temperature 15 ° C., relative humidity 10%). A test for printing 5,000 sheets of horizontal lines with a printing rate of 1% in a two-sheet intermittent mode was performed.
By performing an image printing test in a low-temperature and low-humidity environment (temperature of 15 ° C. and relative humidity of 10%), the toner is more easily charged up and strict evaluation is possible.
After outputting 5,000 sheets, a solid white image was output, and a black spot-like image defect was visually determined. As a result, no black spot-like image defect was observed, and a good image was obtained.
Hereinafter, the judgment criteria will be described.

A: No black spot-like image defect is observed.
B: Slight black spot-like image defects are observed.
C: Black spot-like image defects are generated as a whole.
D: Black spot-like image defects are conspicuous.

<Examples 2 to 26 and Comparative Examples 1 to 7>
For the combinations of toner and charging member shown in Table 10, the same evaluation as in Example 1 was performed. The results are shown in Table 10.

DESCRIPTION OF SYMBOLS 1 Conductive base | substrate 2 Conductive elastic layer 11 Bowl-shaped resin particle 12 Conductive elastic layer (binder)
13 Electrophotographic photoreceptor 14 Charging member 31 Cylindrical metal 32 Bearing 33 Conductive substrate 34 Charging member 35 Stabilizing power source 36 Ammeter 41 Bowl-shaped resin particles 42 Conductive elastic layer (binder)
51 Openings of bowl-shaped resin particles 52 Recesses derived from bowl-shaped resin particles 53 Edges of openings of bowl-shaped resin particles 54 Height difference 55 Maximum diameter of bowl-shaped resin particles 61 Openings 62 Recesses of openings 63 Minimum diameter of opening 71 Bowl-shaped resin particle 72 Conductive elastic layer (binder)
81 A stage 82 on which a charging roller capable of vertical movement is set 82 A glass plate 83 A stage 84 on which a glass plate is fixed 84 A load meter 85 A space 101 formed between the surface of the charging member and the glass plate Charging roller 102 Electrophotographic photosensitive member 103 Developing roller 104 Transfer roller 105 Fixing roller 106 Cleaning member 107 Exposure light 108 Collection container 109 Charging power source

Claims (9)

In a process cartridge detachable from the image forming apparatus main body,
The process cartridge is
An electrostatic latent image carrier;
A charging member for charging the electrostatic latent image carrier;
Developing means for developing the electrostatic charge image formed on the electrostatic latent image carrier using toner;
Have
The charging member has a conductive base and a conductive elastic layer as a surface layer on the conductive base,
The elastic layer comprises 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 particles exposed on the surface, a convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed to the surface, Have
When the Martens hardness of the binder on the surface of the charging member is M1, and the Martens hardness of the binder immediately below the bottom of the concave portion of the charging member is M2, the value of M2 / M1 is less than 1,
The toner contains toner particles and silica fine particles as an external additive,
The silica fine particles are treated with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil based on 100 parts by mass of the silica raw material, and the carbon oil-based immobilization ratio (%) of the silicone oil is A process cartridge characterized by being 70% or more. ^2. The process cartridge according to claim 1, wherein the silica base has a specific surface area (BET specific surface area) measured by a BET method by nitrogen adsorption of 130 m ² / g or more and 330 m ² / g or less.   3. The process cartridge according to claim 1, wherein the silica fine particles are obtained by treating the silica base material with the silicone oil and then treating with at least one of alkoxysilane and silazane. 4. The toner further contains fine particles of an alkaline earth metal titanate as an external additive,
The number average particle diameter (D1) of primary particles of the alkaline earth metal titanate fine particles is 60 nm or more and 200 nm or less,
The process cartridge according to any one of claims 1 to 3, wherein the adhesion rate of the fine particles of the alkaline earth metal titanate is 50% or more and 90% or less.   The process cartridge according to claim 1, wherein the toner particles have an average circularity of 0.960 or more.   The toner particles are obtained by dispersing and granulating a polymerizable monomer composition containing a polymerizable monomer and a colorant in an aqueous medium, and the polymerizable monomer contained in the granulated particles. The process cartridge according to claim 1, which is toner particles obtained by polymerizing a toner.   The process according to any one of claims 1 to 6, wherein the bowl-shaped resin particles are at least one thermoplastic resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, and methacrylonitrile resin. cartridge. The ten-point average surface roughness (Rzjis) of the elastic layer is 5 μm or more and 65 μm or less,
The process cartridge according to any one of claims 1 to 7, wherein the uneven average interval (Sm) is 30 µm or more and 200 µm or less. When the charging member is pressed against the glass plate so that the load on the glass plate is 100 (g),
Average contact area per contact portion between the charging member and the glass plate in a region including at least one contact portion between the charging member and the glass plate in the nip between the charging member and the glass plate Is S1,
In this region, the average spatial distance between the charging member and the glass plate is d1,
When the load on the glass plate is pressed to 500 (g),
In this region, the average contact area per contact portion between the charging member and the glass plate is S5,
When the average spatial distance between the charging member and the glass plate in the region is d5,
S1 and S5 satisfy the relationship represented by the following formula (1),
The process cartridge according to any one of claims 1 to 8, wherein d1 and d5 satisfy a relationship represented by the following formula (2).