JP2008225310A - Developing roller, development method using the same and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller which has high durability, has a stable charging property even under a high-temperature and high-humidity environment, and a low-temperature and low-humidity environment, does not occur problems such as toner splashing and staining in an apparatus, has a stable developing property and can obtain a high-quality image less in fogging, and to provide a non-magnetic one-component development method and an image forming apparatus suited for a non-contact development using the developing roller. <P>SOLUTION: The developing roller is used for a development device in which an electrostatic latent image formed on a latent image carrier is visualized by developing toner deposited and carried on the developing roller, wherein an intermediate layer 3 made of polymer material and a surface layer 4 are directly deposited on the outer circumferential surface of a conductive shaft 1 of the developing roller, and the surface layer 4 is treated with a surface treatment agent having a cationic group and contains inorganic fine particles of which the blowoff charge amount (Q) with iron oxide powder is within the range of +10μC/g < Q <+1,000μC/g. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-magnetic one-component developing method and an image forming apparatus suitable for non-contact development with a developing roller.

  Non-magnetic one-component development is a developing method having excellent characteristics such as a simple developing unit structure and being compatible with color development, and therefore has been widely used in recent years.

  The developing roller used in this developing method is often made of a polymer material (resin), especially in the surface layer. Usually, the layer is charged with a conductive agent and, if necessary, charged to properly charge the toner. A control agent is added and mixed (for example, see Patent Document 1).

  Various charge control agents have been proposed, but it is difficult to disperse uniformly in the resin, and in particular, the abundance that contributes effectively near the surface of the developing roller is insufficient, and the desired chargeability is obtained. There was no problem.

  In particular, in a configuration in which a toner layer is formed on the surface of the developing roller using a metal blade such as stainless steel (SUS) that has been widely used in the past and charged at the same time, it is necessary and sufficient in a regulating portion that forms the toner layer in a thin layer. Thus, it was difficult to ensure a predetermined charge level. For this reason, the toner charge amount distribution is wide, and low charge amount toner, reverse charge amount toner, or overcharge amount toner increases, and it is difficult to obtain a uniformly charged toner. As a result, it is difficult to ensure a uniform and stable developability, and the chargeability is not stable in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment, causing toner scattering and toner adhesion to non-image areas on the photoreceptor. It may cause fogging.

Furthermore, recently, a developing roller having a so-called baseless configuration in which a developing roller does not have an elastic layer and a coating layer (sometimes referred to as a surface layer) is directly formed on a conductive shaft has been developed (patented). In this case, the above tendency is particularly remarkable.
Japanese Patent Laid-Open No. 10-186836 Japanese Patent Laid-Open No. 2005-77869

  The present invention has been made to solve the above problems.

  That is, the object of the present invention is high durability and stable charging property even in a high temperature and high humidity environment or a low temperature and low humidity environment. Therefore, there is no problem such as toner scattering and internal contamination caused by the toner. And a non-magnetic one-component developing method and an image forming apparatus suitable for non-contact development using the developing roller.

  As a result of intensive studies by the present inventors, it has been found that the object of the present invention can be achieved by adopting the following configuration.

(1)
In a developing roller used in a developing device that visualizes an electrostatic latent image formed on a latent image carrier with a developing toner carried on the developing roller, the developing roller is an outer peripheral surface of a conductive shaft. Inorganic fine particles which are directly provided with a surface layer made of a polymer material, and the surface layer is treated with a surface treatment agent having a cationic group, and the contact blow-off charge amount (Q) with the iron oxide powder is within the following range A developing roller comprising:

+10 μC / g <Q <+1000 μC / g
(2)
The surface treatment agent having a cationic group used for treating the inorganic fine particles is at least one of a silane coupling agent having a cationic group or a silicone oil having a cationic group (1) ) Developing roller.

(3)
The developing roller according to (1) or (2), wherein the hydrophobic degree of the inorganic fine particles is 25% or more.

(4)
(1) A developing method comprising performing non-magnetic one-component development using the developing roller according to any one of (3).

(5)
The developing method according to (4), wherein the developing method is non-contact development.

(6)
An image forming apparatus using the developing method according to (4) or (5).

  According to the present invention, the durability is high and the charging property is stable even in a high-temperature, high-humidity environment or a low-temperature, low-humidity environment. Therefore, there is no problem such as toner scattering and resulting internal contamination, and the developing property is stable. Thus, it is possible to provide a developing roller capable of providing a high-quality image with little fogging, a non-magnetic one-component developing method and an image forming apparatus suitable for non-contact development using the developing roller.

  The reason why the effect of the present invention can be obtained by adopting the configuration of the present invention has not been analyzed. However, it is estimated as follows.

  As described above, the non-magnetic one-component developing method is currently attracting attention, and the developing roller used therein has an elastic layer having a considerably large layer thickness ranging from several hundred μm to several thousand μm on the outer peripheral surface of the conductive shaft in many cases. A surface layer that is provided and has a function of charging the toner is formed thereon.

  The reason for this is that in the non-magnetic one-component development method, a thin layer of toner must be formed on the surface of the developing roller, and at the same time, the toner required to be charged during development must be charged. This is because the toner layer needs to be brought into contact with the developing roller with a rotation width (contact width in the rotational direction that effectively works for charging between the developing roller and the toner layer regulating member).

  However, at the same time, it is necessary to accurately define the interval between the developing roller and the electrostatic latent image carrier during development, which is particularly important in the non-contact development method. From this point of view, there is a problem in terms of technology and cost to manufacture a developing roller having an elastic layer controlled with a constant film thickness.

  Furthermore, the development roller having an elastic layer is stable in a low-temperature and low-humidity environment and a high-temperature and high-humidity environment as the development roller is not provided with an elastic layer and studies are conducted focusing on how to charge the toner. It has been found that it is often difficult to impart uniform charging. That is, when an elastic layer is provided, even if an attempt is made to uniformly charge the toner, the toner image is often not uniform when observed strictly. The reason is that after the toner is charged and developed on the surface layer, the counter charge flows through the relatively thick elastic layer to the conductive shaft. An insulator having elasticity.

  A conductive agent such as carbon black is dispersed in order to give an appropriate conductivity to this layer. However, although it is possible to release the charge, it is added in consideration of the point that the characteristic as the elastic layer is not deteriorated. Therefore, the conductivity is not completely uniform, and it becomes difficult to impart stable and uniform electrical characteristics particularly from a low temperature and low humidity environment to a high temperature and high humidity environment. In addition, since it is distorted by a charging blade or the like that is pressed during charging, this also tends to cause creep on the surface of the developing roller or local non-uniformity of conductivity, which acts as a cause of non-uniform charging of the toner. It will be. Actually, the unevenness and unevenness of the charging property appear as density unevenness in the intermediate density portion, toner scattering and fogging.

  In short, from the viewpoint of cost, it is preferable to eliminate the elastic layer if possible, but on the other hand, the absence of the elastic layer naturally reduces the nip width, and the surface layer makes it difficult to charge the toner, so even if the nip width is small. It is necessary to have a method capable of imparting a sufficient amount of charge to the toner uniformly.

  For this purpose, it is considered that it is very effective to include inorganic fine particles treated with a surface treatment agent having a cationic group in the surface layer as in the present invention. That is, since the inorganic fine particles have cationic chargeability, they repel each other and are contained in the surface layer with good dispersibility. Further, when the inorganic fine particles have a certain degree of hydrophobicity, they are easily dispersed in a coating solution using an organic solvent, and when the degree of hydrophobicity is 25 or more, uniform dispersion is facilitated.

  Even if this inorganic fine particle is not contained in a state exposed from the surface layer, if it is in the very vicinity, the particle surface is cationic, so the adjacent surface layer component is negative, and further the portion adjacent to it is This is because the outermost surface layer is cationic. In addition, when the inorganic fine particles are contained in a state exposed from the surface layer, and when the outermost surface portion of the surface layer disappears due to wear and the inorganic fine particles are exposed from the surface layer, the surface of the inorganic fine particles The cationic group directly affects the toner chargeability.

  In this case, as described in detail later, the inorganic fine particles of the present invention are intended to impart an appropriate chargeability to the surface layer of the developing roller. Therefore, it is not preferable that the chargeability imparting ability is too high. In (Q), it was found that +10 μC / g <Q <+1000 μC / g.

  When a developing roller using inorganic fine particles treated with a surface treatment agent having a cationic group and having a charging ability within the scope of the present invention is used, a toner charged appropriately on the negative side can be obtained (FIG. 1 (1) is a schematic depiction of the charge distribution of an example toner particle).

  However, inorganic fine particles having only a charge amount of +10 μC / g or less on the lower limit side are not preferable because the chargeability imparting ability is small and sufficient effects of the present invention cannot be obtained. On the other hand, a developing roller using inorganic fine particles having an excessively high charge amount (Q) forms a toner having a charge distribution as indicated by the dotted line in FIG. This tendency is particularly remarkable when charged in a low temperature and low humidity environment.

  The reason is considered as follows. Particularly in a low-temperature and low-humidity environment, if the toner is charged by a developing roller using inorganic fine particles having a large charge amount (Q), the toner is strongly attracted to the developing roller, and the toner amount adheres to the developing roller more than an appropriate amount. Become. In this case, even in the process of peeling unused toner from the developing roller through the developing process, it cannot be completely removed. Since such toner enters the charging process again while adhering to the developing roller, the charge amount gradually increases and repeatedly receives pressure by the charging member. As a result, if the toner firmly adheres to the developing roller, the negative charging property of the toner also acts to positively charge the new toner supplied onto the developing roller.

  1 (2) -1 shows a state in which the toner is strongly attracted to the developing roller, and FIG. 1 (2) -2 further proceeds, and a filming layer of toner is formed on the surface of the developing roller, and the toner is placed on the toner film. It is a figure which shows the attracted state typically.

  That is, since toner is generated from a negatively charged toner to a positively charged toner, the charge distribution of the toner particles is greatly expanded.

  Further, in order to keep the chargeability, particularly the chargeability in a high-temperature and high-humidity environment and a low-temperature and low-humidity environment, it is preferable that the particle surface is also subjected to a hydrophobization treatment to keep the degree of hydrophobicity at least 25% or more. .

  Next, the compound, image forming material, developing method, image forming apparatus and the like used in the present invention will be described below.

  As described above, the developing roller of the present invention is a developing roller in an electrophotographic image forming method, and is particularly suitable for non-magnetic one-component development using a non-contact developing method.

[Configuration of developing roller]
The configuration of the developing roller of the present invention is, for example, formed along a conductive shaft (also referred to as a shaft core or a shaft body) 1 and an outer peripheral surface of the shaft body 1 as shown in a schematic sectional view in FIG. The intermediate layer 3 and the surface layer 4 are provided (however, the intermediate layer may not be provided). In the developing roller of the present invention, the developing roller is not provided with an elastic layer (usually having a film thickness of about 500 μm to 6.0 mm (6,000 μm)). According to the first aspect of the present invention, “the developing roller is provided with a surface layer made of a polymer material directly on the outer peripheral surface of the conductive shaft,” in short, in the present invention, it exists in a normal developing roller as described above. This means that it does not have an elastic layer.

  An adhesive layer may be provided between the intermediate layer and the conductive shaft. Furthermore, the developing roller of the present invention is not limited to the above two-layer structure. In short, as long as at least one layer (resin layer) made of a polymer material is formed as a surface layer on a conductive shaft. It is good.

[Conductive shaft]
What is necessary is just to use what has been conventionally used as an axial center of a developing roller for a conductive shaft. For example, a rod or hollow cylinder made of metal having a diameter of about 5.0 to 30 mm is used. Examples of the material include aluminum, stainless steel, and iron obtained by plating the surface. In addition, a conductive resin rod or the like can also be used. A metal rod such as stainless steel is typical, but the material is not particularly limited.

[Middle layer]
The material for forming the intermediate layer that may be formed on the outer peripheral surface of the conductive shaft is not particularly limited, but any conventionally known material such as a resin material used for the surface layer and an appropriate amount of a conductive agent may be added. Such materials can be used.

For example, carbon black (furnace black, acetylene black, ketjen black), TiO ₂ , ZnO, SnO ₂ , metal oxides such as iron oxide, graphite, potassium titanate, quaternary ammonium salt, borate, lithium salt, etc. The thing which mix | blended these electrically conductive agents is mention | raise | lifted. Among these, it selects from points, such as favorable adhesiveness with the surface layer 4 formation material, and a film thickness is about 0.5-10 micrometers.

[Surface layer]
The main constituent material of the surface layer is a non-conductive polymer material (resin), and a resin conventionally used for the surface layer of the developing roller can be used. Examples thereof include a mixture of urethane and acrylic urethane, an acrylic silicone copolymer, and the like. And when using the mixture of the said urethane and acrylic urethane, it is preferable to set the mixing ratio of both in the range of urethane / acryl urethane = 10 / 90-90 / 10 by mass ratio.

  The surface layer is desirably set to have a thickness of not more than mm, preferably 3 to 100 μm, more preferably 5 to 50 μm. That is, when the thickness of the surface layer exceeds 100 μm, the charge imparting property to the toner is hardly lowered even by a small amount of wear, so that the wear resistance of the charging roller is practically improved. However, the contact portion with the layer forming blade is likely to be deformed, and the restoration of the deformed portion may be delayed due to the thick film thickness. Furthermore, in general, application with a thick film thickness makes it difficult to form a uniform film and a film having surface smoothness.

  The surface layer can be applied by various coating methods such as dipping coating, roller coating, and spray coating.

  In the surface layer, the inorganic fine particles of the present invention, that is, the inorganic fine particles surface-treated with at least one of a surface treatment agent having a cationic group, preferably a silane coupling agent or a silicone oil having a cationic group. Contained.

  The cationic group in the present invention has a functional group that emits electrons and has a positive chargeability, and includes a normal cationic group or amino group.

  The average particle size of the inorganic fine particles used in the present invention is generally less than 1.0 μm, preferably in the range of 0.005 to 0.3 μm.

  The primary particle size of the inorganic fine particles is measured by observing the inorganic fine particles with a transmission electron microscope, and the magnification at which about 30 to 50 primary particle sizes exist in one field of view according to the particle size of each inorganic fine particle (usually 10,000 to (50,000 times) and capture the image. Images were taken in as many fields as the total number of particles, and the average particle size was determined by analyzing as follows. A transmission electron microscope image is captured by an image processing analyzer LUZEX AP (manufactured by Nireco), binarization processing is performed on the primary particle equivalent portion on this image, and then the projected area of the inorganic fine particles is image-analyzed to correspond to the area. Calculate the particle size. The average particle diameter was determined by calculating the average value of the area equivalent particle diameters of 100 particles.

[Inorganic fine particles]
The surface layer of the developing roller of the present invention was treated with inorganic fine particles treated with a surface treatment agent having a cationic group, particularly preferably a silane coupling agent having a cationic group, and a silicone oil having a cationic group. Contains inorganic fine particles.

  Examples of the inorganic fine particles include silica, titanium dioxide, alumina, zinc oxide, strontium titanate, calcium titanate and the like.

  More specifically, AEROSIL (Aerosil) 50, AEROSIL 90G, AEROSIL 130, AEROSIL 200, AEROSIL 300, AEROSIL 380, AEROSIL TT600, AEROSIL MOX170, AEROSIL MOX80 and AEROSIL COK84 (manufactured by Nippon Aerospace Co., Ltd.) Ca-O-SiL L-90, Ca-O-SiL LM-130, Ca-O-SiL LM-150, Ca-O-SiL M-5, Ca-O-SiL PTG, Ca-O-SiL MS- 55, Ca-O-SiL H-5, Ca-O-SiL HS-5 and Ca-O-SiL EH-5 (above, CABOT (manufactured by Cabot)), Wacker HDK, WACKER N2 0, WACKER U15, WACKER N20E, WACKER T30, WACKER T40 (above, manufactured by WACKER-CHEMIGMMBH), DC FineSilica (produced by Dow Corning), and Francol (Fransol) ) (Manufactured by Fransil), Admafine SO-E2, Admafine SO-E3, Admafine SO-C2, Admafine SO-C3, Admafine SO-C5 (above Admanex) Silica, Carplex # 67, Carplex # 80, Carplex # 100, Carplex # 1120, FPS-1, FPS-3, FPS-4 (manufactured by Shionogi Pharmaceutical Co., Ltd.), Seahosta (Manufactured by Nippon Shokubai Co., Ltd.) wet-process silica such as is available in the market. Moreover, inorganic fine particles produced by a sol-gel method can also be suitably used.

  As titanium dioxide, anatase type available as KA-10, KA-15, KA-20, KA-30, KA-35, KA-80, KA-90 and STT-30 (above, manufactured by Titanium Industry Co., Ltd.) Rutile titanium dioxide, MT-150A, MT-, commercially available as titanium dioxide, KR-310, KR-380, KR-460, KR-480, KR-270 and KV-300 (above, manufactured by Titanium Industry Co., Ltd.) Titanium dioxide manufactured by Teika available as 600B, MT-100S, MT-500B, JR-602S and JR-600A, titanium dioxide manufactured by Nippon Aerosil Co., Ltd. available as P25, and the like can be used.

  As alumina, aluminum oxide C (manufactured by Nippon Aerosil Co., Ltd.) Admafine AO-500, Admafine AO-502, Admafine AO-509, Admafine AO-800, Admafine AO-802, Admafine AO- It is commercially available as 809 (manufactured by Admatechs).

  As zinc oxide, ZINCOX SUPER, ZINCOX SUPER-10, ZINCOX SUPER-20R, ZINCOX SUPER-30, 23-K, 23-K (A), 23-K (C) (manufactured by Hux Itec Corp.), etc. are commercially available. Can be used as a thing.

  Furthermore, as strontium titanate, ST (manufactured by Fuji Titanium Industry Co., Ltd.) or the like can be used as commercially available.

  As calcium titanate, CT (manufactured by Fuji Titanium Industry Co., Ltd.) can be used as commercially available.

[Treatment agent for inorganic fine particles]
As described above, the inorganic fine particles used in the present invention are inorganic fine particles treated with a surface treatment agent having a cationic group, particularly preferably at least a silane coupling agent having a cationic group or a silicone oil having a cationic group. Either one is surface treated.

  As the treating agent having a cationic group, amino group-containing silane, ammonium base-containing silane, and amino-modified silicone oil can be used.

(Amino group-containing silane compound)
The amino group-containing silane is a so-called amino functional silane, and those represented by the following general formula can be used.

XmSiYn
(In the formula, X represents an alkoxy group or a chlorine atom, m represents an integer of 1 to 3, Y represents a hydrocarbon group having a primary to tertiary amino group, and n represents an integer of 1 to 3).

  In particular

(Ammonium base-containing silane compound)
Specific examples of the ammonium base-containing silane include the following.

  Moreover, what substituted the alkoxy group of the said organosilane by the other hydrolysable group and the hydroxyl group is mentioned, These may be used in combination of 2 or more types.

  As the amino-modified silicone oil, those represented by the following general formula can be used.

(Wherein R ₁ represents hydrogen, an alkyl group, an aryl group, or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, and R ₃ and R ₄ represent hydrogen, an alkyl group, or an aryl group, provided that The alkyl group, aryl group, alkylene group, and phenylene group may contain an amine or may have a substituent such as halogen as long as the chargeability is not impaired. Is shown.)
Specifically, the following are available from the market.

Viscosity at 25 ° C Amine equivalent product name (cPs)
SF8417 (made by Torre Silicone) 1200 3500
KF393 (manufactured by Shin-Etsu Chemical Co., Ltd.) 60 360
KF857 (Shin-Etsu Chemical Co., Ltd.) 70 830
KF860 (manufactured by Shin-Etsu Chemical Co., Ltd.) 250 7600
KF861 (Shin-Etsu Chemical Co., Ltd.) 3500 2000
KF862 (Shin-Etsu Chemical Co., Ltd.) 750 1900
KF864 (Shin-Etsu Chemical Co., Ltd.) 1700 3800
KF865 (manufactured by Shin-Etsu Chemical) 90 4400
KF369 (Shin-Etsu Chemical Co., Ltd.) 20 320
KF383 (Shin-Etsu Chemical Co., Ltd.) 20 320
X-22-3680 (manufactured by Shin-Etsu Chemical Co., Ltd.) 90 8800
X-22-380D (manufactured by Shin-Etsu Chemical) 2300 3800
X-22-3801C (manufactured by Shin-Etsu Chemical) 3500 3800
X-22-3810B (manufactured by Shin-Etsu Chemical) 1300 1700
The amine equivalent is equivalent (g / eqiv) per amine and is a value obtained by dividing the molecular weight by the number of amines per molecule.

  The amount of the treatment agent having a cationic group is preferably from 0.1 to 20 parts by weight, particularly preferably from 0.5 to 10 parts by weight, based on 100 parts by weight of the inorganic fine particles.

  In the present invention, inorganic fine particles are treated with a silane coupling agent having a cationic group and / or a silicone oil having a cationic group as described above.

  In addition, in order to hydrophobize the surface of the inorganic fine particles, it is preferable to use a hydrophobizing agent in combination. For example, examples of the hydrophobizing agent include silane coupling agents such as chlorosilane, alkylsilane, alkoxysilane, and silazane, and silicone oil.

  Specifically, the following are mentioned as a silane coupling agent.

  Further, as the silicone oil, for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like are particularly preferable.

  The use amount of the hydrophobizing agent is preferably 1 to 50 parts by mass, more preferably 2 to 30 parts by mass with respect to 100 parts by mass of the inorganic fine particles.

  To treat inorganic fine particles with a surface treatment agent having a cationic group as described above, and preferably a hydrophobizing agent, the surface treatment agent is tetrahydrofuran (THF), toluene, ethyl acetate, methyl ethyl ketone or acetone ethanol, saturated with hydrogen chloride. The mixture is diluted by using a solvent such as ethanol, and the inorganic fine powder is forcibly stirred with a blender or the like, and the diluted solution of the surface treatment agent is added dropwise or sprayed and mixed thoroughly. At that time, devices such as a kneader coater, a spray dryer, a Kalmar processor, and a fluidized bed can be used.

  Next, the obtained mixture is transferred to a vat or the like, placed in an oven, heated and dried. After that, it is sufficiently crushed again with a mixer / jet mill. It is desirable to classify as necessary. In such a method, each surface treating agent may be used simultaneously or separately.

  In addition to this dry method, the inorganic fine powder is immersed in an organic solvent solution of the coupling agent and dried, or the inorganic fine powder is dispersed in water to form a slurry and then the aqueous solution of the surface treatment agent is dropped. There is also a wet processing method in which the inorganic fine powder is then settled, dried by heating, and crushed. The heating temperature is preferably 100 ° C. or higher. When the temperature is lower than 100 ° C., the condensation reaction between the inorganic fine powder and the surface treatment agent is difficult to complete.

  In the present invention, the finally obtained inorganic fine particles preferably have a hydrophobization degree of 25% or more, particularly preferably 50% or more. The upper limit is not particularly limited in the present invention, but the upper limit of inorganic fine particles obtained by the hydrophobizing treatment as in the present invention is about 80%.

[Confirmation method of cationization treatment]
The charge amount of the inorganic fine particles preferably has a contact blow-off charge amount (Q) with the iron oxide powder of +10 μC / g <Q <+1000 μC / g, more preferably +20 μC / g <Q <+800 μC / g.

  The chargeability of the inorganic fine particles can be quantitatively measured by a blow-off charge amount measurement method.

The blow-off charge amount is measured using a blow-off powder charge amount measuring device (manufactured by Toshiba Chemical Co.), and the sample concentration is 0 for an iron powder carrier (Z-150 / 250) (manufactured by Powder Tech) as a standard carrier for measurement. .2% by mass, mixing is shown as the value when mixed for 1 minute with a tumbler mixer. The apparatus conditions are SUS400 mesh, blow pressure 10 N / cm ² , and 60 seconds value.

  The sample concentration (% by mass) is expressed as follows when the mass (x) of the inorganic fine particles treated with the surface treatment agent having a cationic group and the mass (y) of the standard carrier for measurement are used.

Sample concentration (mass%) = {x / (x + y)} × 100
(Measurement of hydrophobicity)
In the present invention, the degree of hydrophobicity is 50 ml of pure water in a 200 ml beaker, and inorganic fine particles treated with a surface treatment agent having a cationic group of 0.2 g are added. While stirring the beaker, methanol dehydrated with anhydrous sodium sulfate is added from the burette, and the degree of hydrophobicity is calculated from the amount of methanol (a) required at the point where the inorganic fine particles are almost not observed on the liquid surface.

Hydrophobicity (%) = {a / (a + 50)} × 100
In the present invention, the degree of hydrophobicity of the inorganic fine particles is preferably 25% or more by the treatment with the hydrophobizing agent.

[Development method]
An example of a non-magnetic one-component developing method using the toner of the present invention will be described, but it is not necessarily limited thereto.

  FIG. 3 is a schematic cross-sectional view illustrating a developing device for developing non-magnetic one-component toner.

  A latent image carrier (photosensitive drum) 10 is formed by an electrophotographic process means or electrostatic recording means (not shown). A developing roller 32 has a surface layer coated on a conductive shaft made of aluminum or stainless steel.

  The toner T is stored in the hopper 6 and is supplied onto the developing roller by a supply roll. The supply roll is made of a foam material such as polyurethane foam, and rotates with a relative speed in the forward or reverse direction with respect to the developing roller 32. Together with the toner supply, the developed toner on the developing roller (undeveloped toner) We are also stripping off. The toner supplied onto the developing roller 32 is uniformly and thinly applied by a toner regulating blade 5 which is a kind of member that performs toner thinning and charging.

  The contact pressure between the toner regulating blade and the developing roller is 3 to 250 N / m, preferably 10 to 100 N / m, as the linear pressure in the direction of the developing roller bus. When the contact pressure is less than 3 N / m, it is difficult to uniformly apply the toner, and the toner charge amount distribution becomes broad, which may cause fogging or scattering. On the other hand, if the contact pressure exceeds 250 N / m, a large pressure is applied to the toner and the toner deteriorates, which is not preferable because toner aggregation occurs. Further, it is not preferable because a large torque is required to drive the developing roller. That is, by adjusting the contact pressure to 3 to 250 N / m, it is possible to effectively loosen the aggregation of the toner of the present invention, and it is possible to instantaneously raise the charge amount of the toner.

  As a material of the member for thinning and charging the toner, it is formed of a material capable of charging the toner to a desired polarity by frictional charging. Specific examples include metal elastic materials such as stainless steel, aluminum, and phosphor bronze, and rubber elastic materials such as silicone rubber, urethane rubber, and styrene-butadiene rubber. Alternatively, a composite layer in which a polyamide resin, a polyimide resin, a melamine resin, a phenol resin, a fluorine resin, a silicone resin, a polyester resin, a urethane resin, a styrene resin, or the like is laminated on the above-described material layer may be formed. Furthermore, by adding conductive rubber, conductive resin, fillers such as metal oxides, carbon black, inorganic whiskers, inorganic fibers, and charge control agents to the elastic material described above, it is possible to improve the charge imparting property. It is. As a member for thinning and charging the toner, an elastic roller can be used in addition to the elastic blade.

  In the present invention, silicone rubber, urethane rubber, styrene-butadiene rubber and the like are suitable. Furthermore, an organic resin layer such as polyamide, polyimide, nylon, melamine, melamine cross-linked nylon, phenol resin, fluorine resin, silicone resin, polyester resin, urethane resin, styrene resin may be provided. In addition, conductive rubber, conductive resin, etc. are used, or fillers such as metal oxides, carbon black, inorganic whiskers, inorganic fibers, and charge control agents are dispersed in blade rubber and resin. It is preferable because it imparts charge imparting properties and can charge the toner appropriately.

  In non-magnetic one-component development in which a thin layer of toner is coated on the developing roller with a blade, the thickness of the toner layer on the developing roller is set to be opposite between the developing roller and the photosensitive drum in order to obtain a sufficient image density. It is preferable that the gap length is smaller than that of the so-called non-contact development method, and an alternating electric field is applied to the gap. A gap of 40 to 300 μm, more preferably 60 to 170 μm, is provided between the photoreceptor surface and the developing roller surface. On the other hand, the toner layer provided on the developing roller overlaps with about 1 to 3 toner particles. A toner layer of ˜30 μm is preferable. The film thickness of the toner layer on the developing roller can be obtained by microscopic observation.

  That is, the developing cartridge loaded in the actual image forming apparatus is irradiated with parallel light from the cross-sectional direction of the developing process, and a high-speed, high-resolution camera (for example, Phototron: FASTCAM MAX, photographing speed 100,000 (FPS)) It can measure from what image | photographed by and visualized the behavior of the image development part.

  The film thickness (a) of the toner layer on the developing roller is such that the gap (b) between the toner layer on the developing roller and the photosensitive member in the area close to the latent image carrier (in most cases, the photosensitive member), the developing roller, The distance (c) at the center of the developing nip sandwiched between the photoreceptors is measured, and the difference (a = c−b) is obtained.

  3 is applied between the developing roller 32 and the photosensitive drum 10 by applying a developing bias in which an alternating electric field or a DC electric field is superimposed on the alternating electric field, from the developing roller to the photosensitive drum. Therefore, it is possible to easily move the toner and to obtain a high-quality image.

[Image Forming Method and Image Forming Apparatus]
An example of a full-color image forming apparatus that forms a full-color image using each color toner will be specifically described with reference to FIG.

  In the full-color image forming apparatus shown in FIG. 4, a charging brush 111 that uniformly charges the surface of the photosensitive drum 10 to a predetermined potential around the photosensitive drum 10 that is rotationally driven, and the photosensitive drum 10 A cleaner 112 for scraping off the remaining toner is provided.

  Further, a laser scanning optical system 20 for scanning and exposing the photosensitive drum 10 charged by the charging brush 111 with a laser beam is provided. The laser scanning optical system 20 includes a laser diode, a polygon mirror, and an fθ optical element. As is well known, print data for each of yellow, magenta, cyan, and black is transferred from the host computer to the control unit. The laser scanning optical system 20 sequentially outputs the laser beam as a laser beam based on the print data for each color, scans and exposes the photosensitive drum 10, and thereby the static image for each color is formed on the photosensitive drum 10. Electro latent images are sequentially formed.

  In addition, the full-color developing device 30 that supplies full-color development to the photosensitive drum 10 on which the electrostatic latent image is formed in this manner, performs yellow, magenta, cyan, and black around the support shaft 33. Four color-developing units 31Y, 31M, 31C, and 31Bk each containing a non-magnetic one-component toner are provided. The developing units 31Y, 31M, 31C, and 31Bk rotate around the support shaft 33. It is guided to a position facing the photosensitive drum 10.

  Further, in each of the developing devices 31Y, 31M, 31C, and 31Bk in the full-color developing device 30, as shown in FIG. 4, the toner is formed on the outer peripheral surface of the developer carrier (developing roller) 32 that rotates and conveys the toner. A regulating member is in pressure contact, and the toner regulating member regulates the amount of toner conveyed by the developing roller 32 and charges the conveyed toner. In the full-color developing device 30, two toner regulating members may be provided in order to appropriately regulate and charge the toner conveyed by the developing roller.

  Then, whenever the electrostatic latent image of each color is formed on the photosensitive drum 10 by the laser scanning optical system 20 as described above, the full-color developing device 30 is rotated around the support shaft 33 as described above. Then, the developing devices 31Y, 31M, 31C, and 31Bk containing toner of the corresponding colors are sequentially guided to positions facing the photosensitive drum 10, and the developing rollers 32 in the developing devices 31Y, 31M, 31C, and 31Bk are moved. Development is performed by sequentially supplying charged toner of each color onto the photosensitive drum 10 in which the electrostatic latent images of each color are sequentially formed as described above in contact with the photosensitive drum 10. It has become.

  Further, an endless intermediate transfer belt 40 that is rotationally driven is provided as an intermediate transfer body at a position downstream of the full-color developing device 30 in the rotation direction of the photosensitive drum 10. The photosensitive drum 10 is rotated in synchronization with the photosensitive drum 10. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 41 so as to come into contact with the photosensitive drum 10, and a portion of a support roller 42 that supports the intermediate transfer belt 40 includes: A secondary transfer roller 43 is rotatably provided, and the recording material S such as recording paper is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43.

  Further, a cleaner 50 that scrapes off the toner remaining on the intermediate transfer belt 40 is provided in a space between the full-color developing device 30 and the intermediate transfer belt 40 so as to be able to contact with and separate from the intermediate transfer belt 40. ing.

  Further, the paper feeding means 60 that guides the recording material S such as plain paper to the intermediate transfer belt 40 includes a paper feeding tray 61 that accommodates the recording material S and the recording material S that is accommodated in the paper feeding tray 61 one by one. The recording material S fed in synchronization with the paper feed roller 62 for feeding paper and the image formed on the intermediate transfer belt 40 is sent between the intermediate transfer belt 40 and the secondary transfer roller 43. The recording material S sent between the intermediate transfer belt 40 and the secondary transfer roller 43 in this way is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43. The toner image is pressed and transferred from the intermediate transfer belt 40 to the recording material S.

  On the other hand, the recording material S on which the toner image is pressed and transferred as described above is guided to the fixing device 70 by the conveying means 66 constituted by an air suction belt or the like, and is transferred by the fixing device 70. The toner image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 100 through the vertical conveyance path 80.

  Next, the operation of forming a full color image using this full color image forming apparatus will be specifically described.

  First, the photosensitive drum 10 and the intermediate transfer belt 40 are rotationally driven in the respective directions at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging brush 11.

  The photosensitive drum 10 thus charged is exposed to a yellow image by the laser scanning optical system 20 to form an electrostatic latent image of the yellow image on the photosensitive drum 10. The yellow image is developed by supplying the yellow toner charged by the toner regulating member as described above from the developing device 31Y in which the yellow toner is accommodated in the photosensitive drum 10, and the yellow toner image is thus formed. The intermediate transfer belt 40 is pressed against the body drum 10 by the primary transfer roller 41, and the yellow toner image formed on the photosensitive drum 10 is primarily transferred to the intermediate transfer belt 40.

  After the yellow toner image is transferred to the intermediate transfer belt 40 in this way, the full-color developing device 30 is rotated around the support shaft 33 as described above, and the developing device 31M containing magenta toner is exposed to light. As in the case of the yellow image described above, the magenta image is exposed to the photosensitive drum 10 charged by the laser scanning optical system 20 to form an electrostatic latent image. The electrostatic latent image is developed by a developing device 31M containing magenta toner, and the developed magenta toner image is primarily transferred from the photosensitive drum 10 to the intermediate transfer belt 40. Black image exposure, development and primary transfer are sequentially performed, and yellow, magenta, cyan, and black toner images are sequentially stacked on the intermediate transfer belt 40. To form a toner image of Rukara.

  When the final black toner image is primarily transferred onto the intermediate transfer belt 40, the recording material S is fed between the secondary transfer roller 43 and the intermediate transfer belt 40 by the timing roller 63, and the secondary transfer roller. The recording material S is pressed against the intermediate transfer belt 40 by 43, and the full color toner image formed on the intermediate transfer belt 40 is secondarily transferred onto the recording material S.

  When the full-color toner image is secondarily transferred onto the recording material S in this way, the recording material S is guided to the fixing device 70 by the conveying means 66, and the full-color toner transferred by the fixing device 70 is transferred. The image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 100 through the vertical conveyance path 80.

[Non-magnetic one-component developer (toner)]
The toner according to the present invention is not particularly limited in its production method, composition and the like. Here, an example is shown as a representative example.

  The developer that can be used in the present invention is preferably a non-magnetic one-component developer. As the toner constituting the non-magnetic one-component developer, a chemical toner typified by a polymerized toner obtained through a step of polymerizing a polymerizable monomer in an aqueous medium to form resin particles is preferably used.

  The particle diameter of the developer (toner) used in the present invention is preferably 3 to 9 μm in terms of volume-based median diameter (volume D50% diameter). The ratio of the developer (toner) having a volume-based median diameter of 4 μm or less is preferably 25% or less, and the ratio of the developer (toner) having a volume of 12 μm or more is preferably 1% or less.

  The volume-based median diameter, the ratio of the developer (toner) whose volume-based median diameter is 4 μm or less, and the ratio of the developer (toner) whose volume is 12 μm or more are the same as those of Coulter Multisizer II (manufactured by Beckman Coulter). It can be measured and calculated using a device connected to a computer system for data processing (manufactured by Beckman Coulter).

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is poured into a beaker containing ISOTON II (manufactured by Beckman Coulter) in a sample stand with a pipette until the measured concentration becomes 5% to 10%, and the measuring machine count is set to 30000. taking measurement. The aperture diameter of the Coulter Multisizer is 100 μm.

  In the present invention, a developer (toner) having a particle size and a particle size distribution within the above range is filled in a developing device or a process cartridge by a known filling method, and when these units are used to form an image. A good toner image without image unevenness can be stably obtained.

[Method for producing developer (toner)]
Next, a method for producing a developer (toner) that can be used in the present invention will be described.

  Here, as a preferred toner for the present invention, a polymerized toner formed through a process of aggregating resin particles in an aqueous medium is taken as an example.

  Resin particles having a mass average particle diameter of 20 to 500 nm can be used. Resin particles having such a size can be prepared by emulsion polymerization to be obtained.

  The step of agglomerating the resin particles in the aqueous medium is performed by adding a salting-out agent having an alkali metal salt, an alkaline earth metal salt, or the like in water in which at least the resin particles, the colorant particles, and the wax particles are dispersed at a critical aggregation concentration or more. Then, it is a step of performing fusion at the same time as agglomeration (hereinafter also referred to as salting out) is advanced by heating to a temperature higher than the glass transition point of the resin particles. This aggregation process is hereinafter referred to as a salting out / fusion process.

  Unlike the method in which the toner used in the present invention is fused after forming aggregated primary particles of resin particles, colorant particles and wax particles, the formation of particles by salting out and the fusion proceed simultaneously, and the toner Since the particles can be prepared, it is presumed that the uniformity of the toner particles is not impaired, and a toner having a uniform chargeability can be stably obtained.

  Here, examples of alkali metal atoms of alkali metal salts and alkaline earth metal salts that are salting-out agents include metal atoms such as lithium, potassium, and sodium, and examples of alkaline earth metal atoms include magnesium, calcium, strontium, and barium. And metal atoms such as Of these, metal atoms such as potassium, sodium, magnesium, calcium, and barium are preferable.

  Examples of constituents of alkali metal salts and alkaline earth metal salts include chlorine salts, bromine salts, iodine salts, carbonates, sulfates, and the like.

  Furthermore, examples of the organic solvent that is infinitely soluble in water include methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, glycerin, acetone, and the like, but preferably methanol having 3 or less carbon atoms, ethanol, 1- Alcohols such as propanol and 2-propanol are preferable, and 2-propanol is more preferable.

  When performing salting-out / fusion, it is preferable to make the time allowed to stand after adding the salting-out agent as short as possible. The reason for this is not clear, but if it is left for a long time after salting out, the aggregation state of the particles may change, the particle size distribution may become unstable, or the surface properties of the fused toner may change. appear.

  The temperature for adding the salting-out agent needs to be at least the glass transition temperature of the resin particles. The reason for this is that if the temperature at which the salting-out agent is added is equal to or higher than the glass transition temperature of the resin particles, the salting-out / fusion of the resin particles proceeds rapidly, but it becomes difficult to control the particle size. There arises a problem that particles having a particle size are generated. The range of the addition temperature may be not higher than the glass transition temperature of the resin particles, but is generally 5 to 55 ° C, preferably 10 to 45 ° C.

  It is also possible to add a salting-out agent below the glass transition temperature of the resin particles, then raise the temperature as quickly as possible, and heat it above the glass transition temperature of the resin particles.

  The time until this temperature rise is preferably less than 1 hour. Furthermore, it is necessary to quickly raise the temperature, and the rate of temperature rise is preferably 0.25 ° C./min or more and 5 ° C./min or less. The upper limit of the temperature rising rate is not particularly clear, but by setting the temperature rising rate within the above range, the progress of salting out and the control of the particle size can be appropriately performed.

<Polymerizable monomer>
Resin particles prepared by emulsion polymerization can be used as the resin particles. As the polymerizable monomer for preparing the resin particles, the radical polymerizable monomer (1) is an essential constituent, and a crosslinking agent (2) can be used as necessary. Further, it is necessary to contain at least one radical polymerizable monomer (3) having the following acidic group. Furthermore, you may contain the radically polymerizable monomer which has a basic group (4).

(1) Radical polymerizable monomer The radical polymerizable monomer component is not particularly limited, and a conventionally known radical polymerizable monomer can be used.

  For example, aromatic vinyl monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers, etc. are used. I can do it.

  Examples of the aromatic vinyl monomer include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of (meth) acrylic acid ester monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, and methacrylic acid. Methyl, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate Etc.

  Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.

  Examples of vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether, and the like.

  Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

  Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.

(2) Crosslinking agent A radical polymerizable crosslinking agent may be used as a crosslinking agent in order to improve the properties of the resin particles.

  Examples of the radical polymerizable crosslinking agent include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diaryl phthalate.

  The radical polymerizable crosslinking agent is preferably used in the range of 0.1 to 10 parts with respect to 100 parts of the total radical polymerizable monomer, although it depends on the characteristics.

(3) Radical polymerizable monomer having an acidic group As the radical polymerizable monomer having an acidic group, for example, a carboxyl group or a sulfone group-containing monomer can be used.

  Examples of the carboxylic acid group-containing monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid monooctyl ester and the like.

  Examples of the sulfonic acid-containing monomer include styrene sulfonic acid, arylsulfosuccinic acid, octyl arylsulfosuccinate, and the like.

  These may have a structure of an alkali metal salt such as sodium or potassium, or an alkaline earth metal salt such as calcium.

(4) Radical polymerizable monomer having a basic group Examples of the radical polymerizable monomer having a basic group include primary amines, secondary amines, tertiary amines, and quaternary ammonium salts. An amine compound such as can be used.

  Examples of amine compounds include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and quaternary ammonium salts of the above four compounds, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacrylic acid. Oxypropyltrimethylammonium salt, acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N-octadecylacrylamide, vinylpyridine, vinylpyrrolidone, vinyl N-methylpyridinium chloride, Vinyl N-ethylpyridinium chloride, N, N-diarylmethylammonium chloride, N, N-dia Lumpur ethyl chloride and the like.

<Radical polymerization initiator>
The radical polymerization initiator used for emulsion polymerization can be used as appropriate as long as it is water-soluble. Peroxide compounds such as potassium persulfate persulfate, ammonium persulfate, etc., 4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salt, etc. Etc.

  Further, the radical polymerization initiator can be combined with a reducing agent and used as a redox initiator, if necessary. By using a redox initiator, the polymerization activity increases, the polymerization temperature can be lowered, and the polymerization time can be further shortened.

  Any temperature may be selected as long as the polymerization temperature is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but a range of 50 to 90 ° C is preferable. However, it is also possible to perform polymerization at room temperature or higher by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).

<Surfactant>
A surfactant is preferably used for the emulsion polymerization of the radically polymerizable monomer. The surfactant that can be used in this case is not particularly limited, but the following anionic or nonionic surfactants can be mentioned as preferable ones.

  As an anionic surfactant, for example, sodium dodecyl benzene sulfonate sulfonate, sodium arylalkyl polyether sulfonate, etc., sodium sulfate dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc. Examples of the fatty acid salts include sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate and the like.

  Examples of the nonionic surfactant include polyethylene oxide, polypropylene oxide, a combination of polyethylene oxide and polypropylene oxide, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester, and the like. I can list them.

  These are mainly used as emulsifiers during emulsion polymerization, but may be used in other steps or for other purposes.

<Colorant>
As the colorant, it is preferable to use an inorganic pigment or an organic pigment.

  Examples of inorganic pigments include conventionally known black pigments and magnetic pigments.

  As the black pigment, for example, carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black can be used.

  These inorganic pigments can be used alone or in combination as required. The amount of the inorganic pigment added is preferably 2 to 20 parts, more preferably 3 to 100 parts by weight of toner (parts by mass, and “parts” means “parts by mass” unless otherwise specified). 15 parts.

  A conventionally well-known organic pigment can be used as an organic pigment. Any organic pigment can be used, but specific organic pigments are listed below.

  Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the pigment for cyan or green include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  These organic pigments can be used alone or in combination as required. The addition amount of the pigment is preferably 2 to 20 parts, more preferably 3 to 15 parts with respect to 100 parts of the toner.

<wax>
The wax that can be used for the toner includes conventionally known waxes. Specifically, polyolefin waxes such as polyethylene wax and polypropylene wax, long-chain hydrocarbon waxes such as paraffin wax and sazol wax, dialkyl ketone waxes such as distearyl ketone, carnauba wax, montan wax, and trimethylolpropane. Tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, trimellit Ester waxes such as acid tristearyl and distearyl maleate, ethylenediamine dibehenyl amide, trimellitic acid tristearyl amide, etc. Such as amide waxes.

<Additive>
In addition to the colorant and wax, the toner usable in the present invention can be added with additives such as a known charge control agent that imparts various functions.

<Filtration and washing process>
Toner particles formed by agglomerating resin particles in the salting-out / fusion process are filtered from an aqueous medium, washed with washing water, and impurities such as surfactant and salting-out agent adhering to the toner particles are removed. Remove. The filtration and washing machine used in this step is not particularly limited, and for example, a centrifuge, a Nutsche, a filter press or the like is used.

<Drying process>
The toner particles after filtration and washing are dried. The dryer used in this step is not particularly limited. For example, spray dryer, vacuum dryer, vacuum dryer, stationary shelf dryer, mobile shelf dryer, fluidized bed dryer, rotary dryer, stirring A type dryer or the like is used. The water content in the toner after drying is preferably 5% by mass or less, and more preferably 2% by mass or less.

<Crushing process>
This process may not be particularly necessary, but the toner particles may become weakly aggregated after drying. In this case, for example, a crushing device such as a jet mill, a Henschel mixer, or a coffee mill may be used. Aggregation may be crushed.

<Tonerization process>
In the toner forming step, the toner particles obtained above may be used as they are, but it is preferable to add an external additive described later for the purpose of improving fluidity, chargeability, and cleaning properties, for example.

  The equipment for adding the external additive is not particularly limited. For example, a known mixer such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, or a V-type mixer can be used.

  The toner of the present invention is preferably used as a non-magnetic one-component developer, but may be used as a magnetic one-component developer in some cases.

<External additive>
The external additive is not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

  A conventionally well-known thing can be used as an inorganic fine particle. Specifically, fine particles such as silica, titania, alumina, strontium titanate, magnesium titanate, calcium titanate, and barium titanate are preferable, and these can be used alone or in combination. Further, these fine particles are more preferably subjected to a hydrophobic treatment.

  Examples of the silica fine particles include commercially available products R-805, R-809, R-812, R-972, R-974, R-976, NX-90, RX-50, manufactured by Nippon Aerosil Co., Ltd., manufactured by Clariant. Commercial products HVK-2150, H-200, commercially available products TS-530, TS-610, TS-720, H-5, MS-5 manufactured by Cabot Corporation, and the like can be given.

  Examples of the titanium fine particles include commercial products T-604 and T-805 manufactured by Nippon Aerosil Co., Ltd., commercial products MT-100B, MT-100S, MT-500BS, MT-600, MT-600SS, and JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC, TG-811F, etc. are mentioned.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm are preferably used. Specific examples include homopolymers such as styrene and methyl methacrylate, and copolymers thereof.

  As the lubricant, for example, a metal salt of a higher fatty acid is preferably used. Specific examples include zinc stearate, such as zinc, aluminum, copper, magnesium, calcium, zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium, calcium, etc. Salts, salts of zinc linoleic acid, calcium and the like can be mentioned.

  The amount of these external additives added is preferably about 0.1 to 5 parts by mass with respect to 100 parts by mass of the toner.

  The present invention will be further described with reference to embodiments. However, of course, the embodiments of the present invention are not limited to these. In the text, “part” means “part by mass”.

[Preparation of treated inorganic fine particles]
Inorganic fine particles 1
15 parts of hexamethyldisilazane (HMDS: hydrophobizing agent) and 5 parts of octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride (a surface treating agent having a cationic group) are dissolved in 500 parts of ethanol, and are hydrophilic. After mixing and stirring 100 parts of reactive silica # 380 (EH-5 manufactured by Cabot Corporation: specific surface area of 380 m ² / g), the solvent ethanol was removed using an evaporator and dried. Next, the silica fine particles were crushed with a Henschel mixer, and the obtained silica fine particles were dried by heating in an oven at 120 ° C. for 3 hours. The obtained hydrophobic silica was finely pulverized (pulverized) with a jet mill and then coarsely classified to obtain hydrophobic silica fine particles having a cationic group. This was designated as inorganic fine particles 1.

Inorganic fine particles 2
In the inorganic fine particles 1, the inorganic fine particles are hydrophilic silica # 200 (M-5 manufactured by Cabot Corporation: specific surface area 200 m ² / g), and the surface treatment agent is 10 parts of hexamethyldisilazane and γ- (2-aminoethyl). Inorganic fine particles 2 were obtained in the same manner as the inorganic fine particles 1 except that 10 parts of aminopropylmethyldimethoxysilane were used.

Inorganic fine particles 3
Inorganic fine particles 1 include inorganic fine particles as hydrophilic silica # 200 (M-5 manufactured by Cabot Corporation: specific surface area 200 m ² / g), and surface treating agent as exemplified compound No. 15 of hexamethyldisilazane and ammonium base-containing silane. . Inorganic fine particles 3 were obtained in the same manner as the inorganic fine particles 1 except that 1 (where X is Cl ⁻ ) was 10 parts.

Inorganic fine particles 4
In the inorganic fine particles 1, the inorganic fine particles are hydrophilic silica # 200 (M-5 manufactured by Cabot Corporation: specific surface area 200 m ² / g), and the surface treatment agent is 10 parts octylsilane and amino-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd .; KF-857) Inorganic fine particles 4 were obtained in the same manner as inorganic fine particles 1 except that the amount was 5 parts.

Inorganic fine particles 5
Inorganic fine particles 1 are inorganic except that the inorganic fine particles are titanium dioxide (KR-380; manufactured by Titanium Industry Co., Ltd., average primary particle size 250 nm), and the surface treatment agent is 10 parts of exemplary compound 1 of amino group-containing silane. Inorganic fine particles 5 were obtained in the same manner as for fine particles 1.

Inorganic fine particles 6
Inorganic fine particles 6 were obtained in the same manner as the inorganic fine particles 5 except that the surface treating agent was 10 parts of n-hexyltrimethoxysilane and 5 parts of the exemplary compound 1) of amino-containing silane.

Inorganic fine particles 7
In the inorganic fine particles 5, the surface treating agent is exemplified by compound No. 10 of n-hexyltrimethoxysilane and ammonium base-containing silane. Inorganic fine particles 7 were obtained in the same manner as the inorganic fine particles 5 except that 1 part (where X is Cl ⁻ ) was 7 parts.

Inorganic fine particles 8
In the inorganic fine particles 5, the inorganic fine particles 8 are formed in the same manner as the inorganic fine particles 5 except that the surface treating agent is 3 parts of n-hexyltrimethoxysilane and 10 parts of amino-modified silicone oil (manufactured by Shin-Etsu Chemical; KF-857). Obtained.

Inorganic fine particles 9
In the inorganic fine particles 1, the inorganic fine particles are hydrophilic silica # 200 (M-5 manufactured by Cabot Corporation: specific surface area 200 m ² / g), and the surface treating agent is 5 parts hexamethyldisilazane and γ- (2-aminoethyl). Inorganic fine particles 9 were obtained in the same manner as the inorganic fine particles 1 except that 15 parts of aminopropylmethyldimethoxysilane was used.

Inorganic fine particles 10
Inorganic fine particles 5 were obtained in the same manner as the inorganic fine particles 5 except that the surface treating agent was 3 parts of amino-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd .; KF-857).

Inorganic fine particles 11
Inorganic fine particle 1 is the same as inorganic fine particle 1 except that the inorganic fine particle is hydrophilic silica # 200 (M-5 manufactured by Cabot Corporation: specific surface area 200 m ² / g) and the surface treating agent is 15 parts of dimethyldichlorosilane. Inorganic fine particles 11 were obtained by this method.

Inorganic fine particles 12
Inorganic fine particle 1 is the same as inorganic fine particle 1 except that the inorganic fine particle is titanium dioxide (KR-380; manufactured by Titanium Industry Co., Ltd., average primary particle size 250 nm) and the surface treating agent is 10 parts of n-hexyltrimethoxysilane. Thus, inorganic fine particles 12 were obtained.

Inorganic fine particles 13
In the inorganic fine particles 1, the same method as the inorganic fine particles 1 except that the inorganic fine particles were made hydrophilic silica # 200 (M-5 manufactured by Cabot Corporation: specific surface area 200 m ² / g) and not treated with a surface treatment agent. Inorganic fine particles 13 were obtained.

Inorganic fine particles 14
In the inorganic fine particles 1, the inorganic fine particles are hydrophilic silica # 200 (M-5 manufactured by Cabot Corporation: specific surface area 200 m ² / g), and the surface treating agent is 1 part of γ- (2-aminoethyl) aminopropylmethyldimethoxysilane. Except that, inorganic fine particles 14 were obtained in the same manner as the inorganic fine particles 1.

Inorganic fine particles 15
In the inorganic fine particles 1, the inorganic fine particles are hydrophilic silica AEROSIL # 200 (manufactured by Nippon Aerosil Co., Ltd .: specific surface area 200 m ² / g), and the surface treatment agent is γ- (2-aminoethyl) aminopropylmethyldimethoxysilane 15 parts. Except that, inorganic fine particles 15 were obtained in the same manner as the inorganic fine particles 1.

Inorganic fine particles 16 (same as inorganic fine particles 15)
In the inorganic fine particles 1, the inorganic fine particles are hydrophilic silica AEROSIL # 200 (manufactured by Nippon Aerosil Co., Ltd .: specific surface area 200 m ² / g), and the surface treatment agent is γ- (2-aminoethyl) aminopropylmethyldimethoxysilane 15 parts. Except that, inorganic fine particles 16 were obtained in the same manner as the inorganic fine particles 1.

  The composition of the inorganic fine particles 1 to 16 is shown in Table 1 below.

  The blow-off charge amount and the degree of hydrophobicity were measured by the measurement methods described above.

[Production of developing rollers 1 to 16]
(Development roller production example 1)
Preparation of intermediate layer composition A reactor equipped with a stirrer, a thermometer, and a nitrogen gas introduction tube was charged with 1000 g of polycarbonate diol (manufactured by Daicel Chemical Industries, "Placcel CD220", number average molecular weight 2000) and 278 g of isophorone diisocyanate, and nitrogen. The mixture was reacted at 100 ° C. for 6 hours under a stream of air to obtain a prepolymer having a free isocyanate value of 3.44%, and 548 g of methyl ethyl ketone was added thereto to obtain a uniform solution of a urethane prepolymer. Subsequently, 1000 g of the urethane prepolymer solution was added in the presence of a mixture consisting of 71.8 g of isophoronediamine, 4.0 g of di-n-butylamine, 906 g of methyl ethyl ketone and 603 g of isopropyl alcohol, and reacted at 50 ° C. for 3 hours. The polyurethane resin solution thus obtained (hereinafter referred to as polyurethane resin (1A)) had a resin solid content concentration of 30% and an amine value of 1.2 KOH (mg / g).

  On the other hand, a reactor equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction pipe was charged with 1400 g of glycidol (manufactured by NOF Corporation, Epiol OH) and a tetramethoxysilane partial condensate (average number of Si, 4, Tama). Chemical Co., Ltd., methyl silicate 51) 8957.9 g was charged, and the mixture was heated to 90 ° C. with stirring under a nitrogen stream, and then reacted with 2.0 g of dibutyltin dilaurate as a catalyst.

  During the reaction, the methanol was distilled off from the water separator, and when the amount reached about 630 g, it was cooled. It took 5 hours to cool after raising the temperature. Subsequently, about 80 g of methanol remaining in the system was removed under reduced pressure at 13 kPa for about 10 minutes. In this way, an epoxy group-containing alkoxysilane partial condensate (2A) was obtained.

  Furthermore, after heating 500 g of the above-mentioned polyurethane resin (1A) to 50 ° C. in the same reactor, 10.95 g of the epoxy group-containing alkoxysilane partial condensate (2A) was added, and the mixture was heated at 60 ° C. under a nitrogen stream. For 4 hours to obtain an alkoxy group-containing silane-modified polyurethane resin.

  100 parts of the alkoxy group-containing silane-modified polyurethane resin thus obtained, 30 parts of ketjen black (carbon black) and 40 parts of a crosslinked urethane resin having a number average primary particle diameter of 20 μm are mixed and dispersed. A layer composition was prepared.

  The Si content in the solid residue in the alkoxy group-containing silane-modified polyurethane resin was 3.3% in terms of silica mass.

Preparation of composition for surface layer In a reactor equipped with a stirrer, thermometer, nitrogen gas inlet tube, and reflux condenser, 310 parts of ε-caprolactone, 150 parts of alcohol-modified siloxane oil (Exemplary Compound 3-3) and tetrabutyl 0.05 parts of titanate was charged and reacted at a temperature of 180 ° C. for 10 hours under a nitrogen stream to obtain a polysiloxane-polyester copolymer having a hydroxyl value of 37, an acid value of 0.40, and a number average molecular weight of 3,030. It was.

  150 parts of the above copolymer and 27 parts of 1,4-butanediol are dissolved in a mixed solvent of 200 parts of methyl ethyl ketone and 100 parts of dimethylformamide, and 91 parts of hydrogenated diphenylmethane with good stirring at 60 ° C. A solution obtained by dissolving diisocyanate (which may be abbreviated as hydrogenated MDI or H12MDI) in 188 parts of dimethylformamide is gradually added dropwise, and after completion of the addition, the reaction is carried out at 80 ° C. for 6 hours to obtain the silicone copolymer polyurethane resin solution of the present invention. Got. This solution was very transparent and had a viscosity of 35.5 Pa · s (25 ° C.) at a solid content of 35%.

  100 parts of the silicone copolymer polyurethane resin thus obtained, 30 parts of ketjen black (carbon black) and 20 parts of inorganic fine particles 1 were added and mixed and dispersed to prepare a coating solution A for the surface layer.

  Next, the intermediate layer composition is formed to a thickness of 15 μm on the surface of a conductive shaft made of an aluminum roller having a diameter of 16 mm, and heat-treated at 100 ° C. for 1 hour. From the polyurethane resin-silica hybrid body, A layer was formed. Further, the surface layer composition was applied at a thickness of 15 μm and treated at 100 ° C. for 1 hour to form a surface layer made of a silicone copolymer polyurethane resin, whereby the developing roller of the present invention was obtained. This is a developing roller 1.

(Production of developing rollers 2 to 15)
In the production of the developing roller 1, the developing rollers 2 to 15 were produced in the same manner as the developing roller 1 except that the inorganic fine particles 1 were changed to the inorganic fine particles 2 to 15.

[Preparation of developing roller 16]
(Preparation of elastic layer forming material)
X-34-424: 100 parts of A / B (silicone rubber, manufactured by Shin-Etsu Chemical Co., Ltd.), X-34-387: 100 parts of A / B (silicone rubber, manufactured by Shin-Etsu Chemical Co., Ltd.) are further dispersed. 80 parts of ketjen black was added to prepare elastic layer forming material 1.

(Preparation of intermediate layer forming material)
A reactor equipped with a stirrer, a thermometer and a nitrogen gas introduction tube was charged with 1000 g of polycarbonate diol (manufactured by Daicel Chemical Industries, “Placcel CD220”, number average molecular weight 2000) and 278 g of isophorone diisocyanate at 100 ° C. under a nitrogen stream. The mixture was reacted for 6 hours to form a prepolymer having a free isocyanate value of 3.44%, and 548 g of methyl ethyl ketone was added thereto to obtain a uniform solution of a urethane prepolymer.

  Subsequently, 1000 g of the urethane prepolymer solution was added in the presence of a mixture consisting of 71.8 g of isophoronediamine, 4.0 g of di-n-butylamine, 906 g of methyl ethyl ketone and 603 g of isopropyl alcohol, and reacted at 50 ° C. for 3 hours. The polyurethane resin solution thus obtained had a resin solid content concentration of 30% and an amine value of 1.2 KOH (mg / g).

  On the other hand, a reactor equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction pipe was charged with 1400 g of glycidol (manufactured by NOF Corporation, Epiol OH) and a tetramethoxysilane partial condensate (average number of Si, 4, Tama). Chemical Co., Ltd., methyl silicate 51) 8957.9 g was charged, and the mixture was heated to 90 ° C. with stirring under a nitrogen stream, and then reacted with 2.0 g of dibutyltin dilaurate as a catalyst.

  During the reaction, methanol in the water separator was distilled off, and the reaction was cooled when the amount reached about 630 g. It took 5 hours to cool after raising the temperature. Subsequently, about 80 g of methanol remaining in the system was removed under reduced pressure at 13 kPa for about 10 minutes. In this way, an epoxy group-containing alkoxysilane partial condensate was obtained.

  Furthermore, after heating 500 g of the above-mentioned polyurethane resin to 50 ° C. in the same reaction apparatus, 10.95 g of the epoxy group-containing alkoxysilane partial condensate was added and reacted at 60 ° C. for 4 hours under a nitrogen stream. An alkoxy group-containing silane-modified polyurethane resin was obtained.

  100 parts of the alkoxy group-containing silane-modified polyurethane resin thus obtained and 35 parts of ketjen black were added and mixed and dispersed to prepare an intermediate layer forming material for an intermediate layer immediately below the surface layer.

(Preparation of surface layer forming material)
A reactor equipped with a stirrer, thermometer, nitrogen gas inlet tube, and reflux condenser was charged with 310 parts of ε-caprolactone, 150 parts of alcohol-modified siloxane oil and 0.05 parts of tetrabutyl titanate, and under a nitrogen stream. The reaction was carried out at a temperature of 180 ° C. for 10 hours to obtain a polysiloxane-polyester copolymer having a hydroxyl value of 37, an acid value of 0.40, and a number average molecular weight of 3,030.

  150 parts of the above copolymer and 27 parts of 1,4-butanediol are dissolved in a mixed solvent of 200 parts of methyl ethyl ketone and 100 parts of dimethylformamide, and 91 parts of hydrogenated diphenylmethane with good stirring at 60 ° C. A solution obtained by dissolving diisocyanate (which may be abbreviated as hydrogenated MDI or H12MDI) in 188 parts of dimethylformamide was gradually added dropwise and reacted at 80 ° C. for 6 hours to obtain a silicone copolymer polyurethane resin solution. . This solution was very transparent and had a viscosity of 35.5 Pa · s (25 ° C.) at a solid content of 35%.

  100 parts of the silicone copolymer polyurethane resin thus obtained, 35 parts of ketjen black and 25 parts of inorganic fine particles 16 were added to prepare a liquid for the surface layer of the developing roller 16.

(Production roller development)
Next, a conductive shaft made of an aluminum roller having a diameter of 11 mm is set inside the roller of the mold, and the elastic layer forming material obtained above is formed in the gap between the conductive shaft and the inner peripheral surface of the roller mold. Is cast, heat vulcanized (180 ° C. × 1 hour), demolded, and further subjected to secondary vulcanization (200 ° C. × 4 hours) to form an elastic layer (thickness) on the outer periphery of the conductive shaft. 5 mm) was formed.

  The conductive shaft with the elastic layer thus obtained is removed from the mold, the intermediate layer forming material is formed on the outer peripheral surface of the elastic layer with a thickness of 15 μm, and is heated at 100 ° C. for 1 hour. Then, a layer made of a polyurethane resin-silica hybrid was formed. Further, the surface layer forming material was applied at a thickness of 15 μm and treated at 100 ° C. for 1 hour to form a surface layer made of a silicone copolymer polyurethane resin, whereby the developing roller 16 was obtained.

(Characteristic evaluation)
Next, the developing roller obtained as described above was mounted on a commercially available printer (manufactured by Konica Minolta: Magiccolor 2300DL non-contact non-magnetic one-component development), and the following evaluation was performed. The linear pressure of the regulating member pressed against the surface of each developing roller 1 to 16 was changed to 70 N / m, and the system speed was changed to 160 mm.

  Using each printer equipped with the developing rollers 1 to 16 as described above, at a temperature of 35 ° C. and a humidity of 85% in a high temperature / high humidity environment (H / H), a temperature of 25 ° C. and a humidity of 55% The printing durability test of 3000 sheets was performed in an environment of normal humidity (N / N) and a temperature of 10 ° C. and a low temperature / low humidity environment of 15% humidity (L / L).

(Fog on photoconductor)
In each environment, each image portion of yellow (Y), magenta (M), cyan (C), and Bk (black) is 1.25%, a total of 5.0% of the image is printed continuously 100 sheets, and then white The image forming apparatus is forcibly stopped during image output, and the fog on the photosensitive member at that time is visually observed, and then peeled off with a book tape (manufactured by Kihara: Amenity B Coat T; 30 mm width). It was visually observed after pasting on top. The evaluation was made at the initial stage of printing and after printing 3000 sheets under each temperature and humidity environment.

◎: No fogging occurred on the photoconductor ○: Fog on the photoconductor was slightly observed, but no fogging on the paper was observed △: Some fogging on the photoconductor was observed, but practical use The above-mentioned fog is at a level where there is no practical problem. X: The fog on the photoconductor is generated on the entire surface, and the fog on the paper is practically problematic (density unevenness / scratch).
In each environment, 100 images were continuously printed with a total of 5.0% of yellow (Y), magenta (M), cyan (C), and Bk (black) image areas, and visually observed. did. The evaluation was made at the initial stage of printing and after printing 3000 sheets under each temperature and humidity environment.

◎: There is no density unevenness or blurring in the naked eye observation ○: There is a slight density unevenness or blurring in the naked eye observation, but it is not much of concern Tables 2 and 3 show the evaluation results with obvious unevenness (density difference) and blurring. However, for both the fog on the photosensitive member, the density unevenness, and the blur, “/” represents the characteristics of “initial stage of printing durability test / after 3000 sheets printing”.

  When the developing rollers 1 to 10 in the present invention are used, good results can be obtained. However, when the rollers 11 to 16 other than the present invention are used, at least one of the characteristics is problematic. .

  That is, Examples 1 to 10 of the present invention were compared with Comparative Examples 1 to 5 (not treated with a surface treatment agent having a cationic group or treated with a surface treatment agent having a cationic group, but the charge amount (Q ) Using inorganic fine particles outside the scope of the present invention) and Comparative Example 6 (with an elastic layer and using inorganic fine particles treated with a surface treatment agent having a cationic group). Obviously, it can be seen that the effects of the present invention are not obtained except for combinations of the constituent features of the present invention.

FIG. 6 is a diagram schematically illustrating a charge distribution of toner particles and a state where strongly charged toner is attached to a developing roller. FIG. 3 is a schematic cross-sectional view showing a configuration of a roller of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a developing device for developing non-magnetic single component toner. 1 is a configuration cross-sectional view of an example of a full-color image forming apparatus.

Explanation of symbols

1 Conductive shaft (rotating shaft)
DESCRIPTION OF SYMBOLS 3 Intermediate | middle layer 4 Surface layer 10 Photosensitive drum 20 Laser scanning optical system 30 Full color developing device 31, 31Y, 31M, 31C, 31Bk Developing device 32 Developer carrier (developing roller)
33 Support shaft 40 Intermediate transfer belt 50 Cleaner 60 Paper feed means 70 Fixing device 80 Vertical conveyance path S Recording material

Claims (6)

In a developing roller used in a developing device that visualizes an electrostatic latent image formed on a latent image carrier with a developing toner carried on the developing roller, the developing roller is an outer peripheral surface of a conductive shaft. Inorganic fine particles which are directly provided with a surface layer made of a polymer material, and the surface layer is treated with a surface treatment agent having a cationic group, and the contact blow-off charge amount (Q) with the iron oxide powder is within the following range A developing roller comprising:
+10 μC / g <Q <+1000 μC / g The surface treatment agent having a cationic group used for treating the inorganic fine particles is at least one of a silane coupling agent having a cationic group or a silicone oil having a cationic group. The developing roller according to 1. The developing roller according to claim 1, wherein the hydrophobic degree of the inorganic fine particles is 25% or more. A developing method comprising performing non-magnetic one-component development using the developing roller according to claim 1. The development method according to claim 4, wherein the development method is non-contact development. An image forming apparatus using the developing method according to claim 4.

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