JP2005121958A - Single component developing toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide single component developing toner which causes no triboelectric failure of the toner due to contamination of a toner carrier with conductive fine particles and no resulting image defect, and keeps favorable developing property so as to enable to form a high definition image for a long time. <P>SOLUTION: The toner comprises toner particles and conductive metal compound fine particles and inorganic fine particles on the toner particle surfaces. The toner particles comprise at least a binder resin and a coloring agent. The toner has the weight average particle size of 3-12 μm. By the triboelectric charging between the metal compound fine particles and the toner carrier, the metal compound fine particles has the same polarity of charges as the toner, and an absolute value of triboelectric charges is 0.5-20 (mC/kg). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming method for developing and developing a latent image formed on an image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric, and a toner used in the image forming method.

  Conventionally, many methods are known as electrophotographic methods. Generally, a charging process for charging an image carrier using a photoconductive substance and an electrostatic latent image are formed on the charged image carrier. And a developing step for developing the electrostatic latent image formed on the image carrier, and thereafter, the developed image is transferred to a transfer material by a transfer unit depending on the system. A target copy is obtained through a transfer step of transferring and a fixing step of heating and fixing the transferred image transferred onto the transfer material.

  Development methods in electrophotography are mainly divided into a one-component development method and a two-component development method. In recent years, since it is necessary to reduce the size of a copying apparatus for the purpose of reducing the weight and size of an electrophotographic apparatus, a developing apparatus using a one-component developer is often used. For example, as a developing method using one-component toner, a jumping developing method is proposed in Patent Document 1 and the like.

  As a developing method using this one-component toner, an electrostatic latent image is formed on the surface of a photosensitive drum as an image carrier, and in the development process, friction between a developing sleeve as a toner carrier and toner particles, and / or Alternatively, a positive or negative charge is applied to the toner particles by friction between the developer regulating member that regulates the toner application amount on the developing sleeve and the toner particles, and the toner is thinly applied on the developing sleeve to form the photosensitive drum and the developing sleeve. Is conveyed to a developing area that is in contact with or in close proximity, and in the developing area, the toner is developed by flying and adhering to the electrostatic latent image on the surface of the photosensitive drum, and the electrostatic latent image is visualized as a toner image. Are known. In general, in such a method, after the transfer, the toner remaining without being transferred onto the recording medium on the image carrier is cleaned by various methods and stored in a waste toner container as waste toner. Repeated image forming methods have been used.

  On the other hand, as a system without waste toner, a technique called simultaneous development cleaning or cleanerless has been proposed. Patent Documents 2 to 9 and the like disclose techniques related to this cleanerless, but no detailed and specific configuration of the entire system is mentioned.

  In the simultaneous development cleaning that essentially does not have a cleaning device, it has become essential to rub the surface of the image carrier with toner and the toner carrier. Therefore, as a preferred development method, toner or toner is applied to the image carrier. Many contact development methods that come into contact have been studied. This is because it is considered that a configuration in which the toner or toner contacts and rubs the image carrier in order to collect the transfer residual toner in the developing unit is advantageous. However, the simultaneous development cleaning or the cleaner-less process using the contact development method causes toner deterioration, toner carrier surface deterioration, image carrier surface deterioration or wear, etc. due to long-term use, and is a sufficient solution to durability characteristics. Not done.

  On the other hand, a direct injection charging mechanism has been proposed as a new environment-friendly new technique that enables simultaneous development cleaning not only in a contact development system but also in a non-contact development system and does not generate active ions such as ozone.

  This direct injection charging mechanism will be briefly described.

  The direct injection charging mechanism is a mechanism in which the surface of the charged body is charged by directly injecting charges from the contact charging member to the charged body. It is also called direct charging, injection charging, or charge injection charging. More specifically, a medium-resistance contact charging member comes into contact with the surface of the member to be charged, and charge is directly injected into the surface of the member to be charged without going through a discharge phenomenon, that is, basically using no discharge. Therefore, even if the applied voltage to the contact charging member is an applied voltage that is equal to or lower than the discharge threshold, the object to be charged can be charged to a potential corresponding to the applied voltage. Since this charging system is not accompanied by the generation of ions, there is no adverse effect caused by the discharge products. However, since it is direct injection charging, the number of contact points and the contact area of the contact charging member to the member to be charged greatly affect the charging property. Therefore, in order to take a configuration that contacts the charged body at a higher frequency, a configuration is required in which the contact charging member is provided with a denser contact point, and the contact time with the charged body is maintained longer.

  Among them, as a method for increasing the density of the contact points between the charging member and the charged body, there is a high efficiency by providing conductive charge-promoting particles at the contact portion between the charging member and the charged body, so-called image carrier. A method for ensuring a good injection chargeability has been proposed.

  For example, in Patent Document 10, a developer containing toner particles and electrically conductive charge accelerating particles having a particle size equal to or less than ½ of the toner particle size is applied to a developing and cleaning image forming method using a direct injection charging mechanism. An image forming apparatus is disclosed. According to this proposal, it is possible to obtain a developing and cleaning image forming apparatus which can greatly reduce the amount of waste toner without generating a discharge product and is advantageous for downsizing at low cost. Alternatively, a good image that does not cause diffusion can be obtained.

  Further, according to Patent Document 10, conductive fine particles are externally added to the toner, and the conductive fine particles contained in the toner are developed at least at the contact portion between the flexible contact charging member and the image carrier. Development and cleaning that provides a good image that does not cause poor charging and shading of image exposure by adhering to the image carrier in the process and remaining on the image carrier after the transfer process. An image forming apparatus is disclosed.

  In Patent Document 11, a developer containing conductive fine particles having a particle size of 1/50 to 1/2 of the toner particle size is applied to a developing and cleaning image forming method using a direct injection charging mechanism. An image forming apparatus in which fine particles have a transfer promoting effect is disclosed.

  Further, in Patent Document 12, the particle diameter of the metal fine particles is set to 10 nm to 50 μm in order to make the particle diameter of the conductive fine particles equal to or smaller than the size of one constituent pixel and to obtain better charging uniformity. It is described.

  In Patent Document 13, in consideration of human visual characteristics, the conductive fine particles may be about 5 μm or less, preferably 20 nm to 5 μm, in order to make it difficult to visually recognize the influence of the poorly charged portion on the image. Has been described.

  Further, according to Patent Document 14, by setting the particle size of the conductive fine particles to be equal to or smaller than the toner particle size, the development of the toner is inhibited during development, or the development bias is prevented from leaking through the conductive fine particles. By eliminating the defects in the image and setting the particle size of the conductive fine particles to be larger than 0.1 μm, the adverse effect of shielding the exposure light by embedding the conductive fine particles in the image bearing member can be solved. A developing and cleaning image forming method using a direct injection charging mechanism for realizing recording is described.

  On the other hand, Patent Document 15 discloses a technique for strictly controlling the particle size distribution of a developer containing conductive fine particles and improving not only direct injection charging properties but also image characteristics.

  For the purpose other than the improvement of the charging property, many methods for adding conductive fine particles as an external additive to the toner have been proposed for improving the image quality of the copy. For example, carbon black as conductive fine particles is used to attach or adhere to the toner surface for the purpose of imparting conductivity to the toner, or for the purpose of suppressing excessive charging of the toner and making the tribo distribution uniform. It is widely known to use as an external additive. Patent Documents 16 to 18 disclose that conductive fine particles of tin oxide, zinc oxide, and titanium oxide are externally added to the high-resistance magnetic toner, respectively. In Patent Document 19, conductive properties such as iron oxide, iron powder, and ferrite are added to a high-resistance magnetic toner, and charge induction to the magnetic toner is promoted in the conductive magnetic particles so that developability and transferability are achieved. Toners that satisfy both requirements have been proposed. Furthermore, Patent Documents 20 to 23 disclose that graphite, magnetite, polypyrrole conductive fine particles, and polyaniline conductive fine particles are added to the toner, and it is known that a wide variety of conductive fine particles are added to the toner. ing.

  However, in Patent Documents 10 to 14, although the preferable particle size of the conductive fine particles is described to some extent, the particle size distribution or the constituent elements are not described, and in order to always obtain stable performance, further improvement is required. There is room for improvement.

  Also in Patent Document 15, sufficient performance cannot always be obtained, and it is necessary to view the conductive material on a scale different from the conventional one, and there is still room for improvement.

  In addition, when conductive fine particles are added to the toner as an external additive to improve image characteristics, the toner particles are selected mainly by paying attention to the interaction between the toner particles and these conductive fine particles. However, the conductive fine particles interact with not only the toner but also the toner carrier by frictional charging, and the behavior has a great influence on the durability.

  For example, in the study by the present inventors, when the triboelectric charging characteristic between the external additive and the toner carrier exhibits a polarity different from that of the triboelectric charging characteristic between the toner and the toner carrier, only the toner is consumed in the development. It was found that the additive tends to accumulate on the toner carrier. Therefore, if the durability test is continued for a while, normal frictional charging of the toner is inhibited, and there are problems such as deterioration of fog and a decrease in image density. Furthermore, when it is employed in a direct injection charging system, the supply of conductive fine particles from the toner carrier to the photoconductor is insufficient, and there is a concern about deterioration of the charging property.

  Note that the triboelectric charging characteristics between the external additive to the toner and the toner carrier are mentioned in Patent Documents 24 and 25.

  The external additive described in Patent Document 24 is limited to insulating fine powder, and is different from the conductive fine particles described in the present invention.

  The external additive described in Patent Document 25 has a content limited to fluidity imparting agents such as silica, titanium oxide, and alumina, and the present application focusing on conductive fine particles used in combination with the fluidity imparting agent The technical contents are still different.

Japanese Patent Laid-Open No. 55-18656 JP 59-133573 A JP-A-62-203182 JP-A-63-133179 JP-A 64-20587 Japanese Patent Laid-Open No. 2-302772 JP-A-5-2289 Japanese Patent Laid-Open No. 5-53482 JP-A-5-61383 JP-A-10-307456 Japanese Patent Laid-Open No. 10-307421 JP-A-10-307455 Japanese Patent Laid-Open No. 10-307457 JP-A-10-307458 JP 2001-235891 A JP 57-151952 A JP 59-168458 A JP 60-69660 A JP-A-56-142540 JP-A 61-275864 JP-A-62-258472 Japanese Patent Laid-Open No. 61-141452 Japanese Patent Laid-Open No. 02-120865 JP-A-57-52060 JP-A-6-236065

  The object of the present invention has been made in view of the above-mentioned problems, and does not cause toner triboelectric charge failure and image defects due to contamination of the toner carrier with conductive fine particles, and maintains good developability and high definition. Another object of the present invention is to provide a one-component developing toner and an image forming method that enable easy image formation over a long period of time.

  Another object of the present invention is to provide a simple and stable uniform charging to a photoconductor by a direct injection charging mechanism that substantially eliminates the generation of discharge products such as ozone and can obtain uniform charging at a low applied voltage. An image forming method is provided.

  Another object of the present invention is to provide a toner and an image forming method capable of stably reducing the amount of waste toner and enabling a simultaneous development cleaning process that is advantageous for downsizing at low cost. .

  The above object is achieved by a toner and an image forming method having the following configuration.

A charging step for charging the latent image carrier, a latent image forming step for writing image information as an electrostatic latent image on the charging surface of the latent image carrier charged in the charging step, and the electrostatic latent image for the toner When developing and visualizing using a developing device provided with a toner carrier that conveys toner to a development region facing the latent image carrier, the toner carrier comprises at least a substrate and a surface of the substrate. And a developing step having a resin coating layer formed of a resin composition, and a toner used in an image forming method for forming an image by repeating these steps,
The toner has at least toner particles and conductive metal compound fine particles and inorganic fine powder on the surface of the toner particles,
The toner particles are formed of at least a binder resin and a colorant,
The toner has a weight average particle diameter of 3 μm or more and 12 μm or less;
In frictional charging between the metal compound fine particles and the toner carrier, the metal compound fine particles exhibit the same charging polarity as the toner, and the absolute value of the triboelectric charge amount is 0.5 (mC / kg) or more and 20 (mC / kg). Toner characterized by:

Moreover,
A charging step for charging the latent image carrier, a latent image forming step for writing image information as an electrostatic latent image on the charging surface of the latent image carrier charged in the charging step, and the electrostatic latent image for the toner When developing and visualizing using a developing device provided with a toner carrier that conveys toner to a development region facing the latent image carrier, the toner carrier comprises at least a substrate and a surface of the substrate. And an image forming method for forming an image by repeating each of the steps, and a development step having a resin coating layer formed of a resin composition.
The toner has at least toner particles, conductive metal compound fine particles and inorganic fine powder on the surface of the toner particles,
The toner particles are formed of at least a binder resin and a colorant,
The toner has a weight average particle diameter of 3 μm or more and 12 μm or less;
In frictional charging between the metal compound fine particles and the toner carrier, the metal compound fine particles exhibit the same charging polarity as the toner, and the absolute value of the triboelectric charge amount is 0.5 (mC / kg) or more and 20 (mC / kg). An image forming method comprising:

It is more preferable to have the following configuration. That is,
The specific surface area (cm ² / cm ³ ) of the metal compound fine particles is 5 × 10 ⁵ or more and 100 × 10 ⁵ or less, and the volume-based median diameter (D ₅₀ ; unit μm) is 0.4 μm or more and 4.0 μm or less. is the mass average particle diameter smaller than the toner, it D ₉₀ of at large 6.0μm or less than 0.5 [mu] m.

  The metal compound fine particles are non-magnetic.

The volume resistance of the metal compound fine particles is 1 × 10 ⁻¹ to 1 × 10 ⁹ Ωcm.

The specific surface area (cm ² / cm ³ ) and volume-based median diameter (D ₅₀ ; unit μm) of the metal compound fine particles are 5 × 10 ⁵ / D ₅₀ ≦ specific surface area (cm ² / cm ³ ) ≦ 100 × 10 ⁵ / D ₅₀
Satisfy the relationship.

When the content of the metal compound fine particles with respect to the toner is X (mass%) and the toner specific gravity is Y (g / cm ³ ),
0.5 ≦ X × Y ≦ 6.0
Satisfy the relationship.

The volume-based median diameter D _{50 of the} metal compound fine particles is from 0.5 μm to 3.5 μm.

The volume-based D ₉₀ of the metal compound fine particles is larger than 0.5 μm and not larger than 4.0 μm.

The volume-based D ₁₀ of the metal compound fine particles is 0.3 μm or more and less than 3.5 μm.

The specific surface area (cm ² / cm ³ ) of the metal compound fine particles is 10 × 10 ⁵ or more and 80 × 10 ⁵ or less.

The specific surface area (cm ² / cm ³ ) of the metal compound fine particles is 12 × 10 ⁵ or more and 40 × 10 ⁵ or less.

The volume-based D ₁₀ of the metal compound fine particles is 0.4 μm or more and less than 3.5 μm.

  The metal compound fine particles contain at least tin oxide.

  The metal compound fine particles have been surface-treated with a silicon compound.

  The inorganic fine powder is selected from at least silica, titanium oxide, alumina, a composite thereof, or a mixture thereof, and has an average primary particle size of 4 nm to 80 nm.

In the triboelectric charging between the metal compound fine particles and the toner carrier, the triboelectric charge amount indicated by the metal compound fine particles is A, and in the triboelectric charging between the toner and the toner carrier, the triboelectric charge amount indicated by the toner is B. Time,
0.05 ≦ | A / B | ≦ 2
Be.

  The toner is a magnetic toner having a magnetic material.

  The toner carrier has at least a base and a negatively chargeable resin coating layer formed of a resin composition on the surface of the base.

  In the developing step, the transfer residual toner remaining on the latent image carrier after the transfer step is collected by the toner carrier.

  In the developing step, the latent image carrier and the toner carrier are arranged at a predetermined interval, a toner layer is formed on the surface of the toner carrier with a thickness smaller than the interval, and an alternating electric field is applied. The development is performed by transferring the toner to the electrostatic latent image in the developed area.

  The latent image carrier is repeatedly used for image formation, and has a mode in which a voltage obtained by superimposing a DC voltage and an AC voltage is applied to the charging member during non-image formation. The frequency of the AC voltage in the mode is 5 to 1000 Hz. To do.

a. The charging step for charging the latent image carrier is a charging step for charging the surface of the latent image carrier with a flexible charging member that forms a contact portion with the latent image carrier, and at least the charging member and the latent image carrier. There are conductive fine particles in the contact part with
b. The metal compound fine particles in the toner that has been transferred to the latent image carrier in the development step and remained on the latent image carrier after the transfer step are carried to the contact portion between the charging member and the latent image carrier. Fine particles are supplied,
about.

  The resin coating layer formed on the base of the toner carrier is made of at least a binder resin for the coating layer and a substance for making the resin coating layer negatively chargeable.

The binder resin for the coating layer of the resin coating layer formed on the substrate of the toner carrier is partially or entirely of —NH ₂ group, ═NH group, or —NH— bond in the molecular structure. Have at least one of them.

The coating resin for the coating layer is a phenol resin produced by adding and condensing phenols and aldehydes using a nitrogen-containing compound as a catalyst. In the structure, -NH ₂ group, = NH group, Or it is a phenol resin which has either -NH- bond.

  The resin coating layer contains at least a quaternary ammonium salt compound that is positively charged with respect to iron powder.

  The substance for making the resin coating layer negatively charged is a benzylic acid compound.

  The resin coating layer further has particles for forming irregularities having a number average diameter of 0.3 to 30 μm in the binder resin for the coating layer.

  The particles for forming the irregularities are spherical resin particles.

The particles for forming the irregularities are conductive spherical particles having a true density of 3 g / cm ³ or less.

  The negatively chargeable resin coating layer is a conductive resin coating layer in which a conductive substance is further dispersed in the coating layer binder resin.

  The conductive resin coating layer further has lubricating particles.

  According to the present invention, it is possible to obtain a one-component developing toner exhibiting excellent performance in image characteristics and durability characteristics. In particular, even when it is difficult to obtain a sufficient amount of triboelectric charge, if the toner is used, it is possible to obtain a high-quality image with a high image density and little fogging for a long time without causing contamination of the toner carrier. Become.

  Furthermore, the image quality is further improved by combining with a special image forming method.

  In the present invention, first, a toner carrier having at least a substrate and a resin coating layer formed of a resin composition on the surface of the substrate when the electrostatic latent image carrier is developed and visualized using a developing device equipped with a toner carrier. Is used. As a result, toner adhesion on the toner carrier can be prevented.

  Next, the toner to be used has at least toner particles, conductive metal compound fine particles and inorganic fine powder on the surface of the toner particles, and the toner particles are formed of at least a binder resin and a colorant, The toner has a weight average particle diameter of 3 μm or more and 12 μm or less in order to achieve high image quality.

  When the thickness is less than 3 μm, transferability is deteriorated and fog is deteriorated. The addition of the metal compound fine particles shown below can be improved to some extent. However, for example, in the simultaneous development cleaning employing a direct injection charging mechanism, a decrease in charging property cannot be avoided. On the other hand, if the weight average particle size exceeds 12 μm, the resolution on the image is lowered, and improvement from the system is difficult. By using such a small particle size toner, a high-definition image can be formed in the present application. Further, since the conductive fine particles are included, the triboelectric charge amount does not become abnormally high even under low humidity, and a high-definition image can be maintained.

In this example, the weight average particle diameter of the toner was determined as follows. Using Coulter Multisizer (manufactured by Coulter), an interface (manufactured by Nikka) and a PC9801 personal computer (manufactured by NEC) that output number distribution and volume distribution are connected, and the electrolyte is 1% NaCl using first grade sodium chloride. Prepare an aqueous solution. As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is dispersed for about 1 to 3 minutes using an ultrasonic disperser, and the volume distribution is determined by measuring the volume and number of toner particles of 2 μm or more using the 100 μm aperture as the aperture by the Coulter Multisizer. And the number distribution were calculated. Then, the volume-based weight average particle diameter (D ₄ ) determined from the volume distribution related to the present invention was determined.

  In addition, in frictional charging between the metal compound fine particles and the toner carrier, the metal compound fine particles have the same charging polarity as that of the toner.

  As a result, both the toner particles and the metal compound fine particles are consumed in the development process, so that the toner carrier is not contaminated by the metal compound fine particles, the abnormal frictional charging of the toner is suppressed, and a high-definition image is obtained over a long period of time. Stable across.

  This effect is prominent when, for example, “one image standby state after five images are printed continuously” is one operation, and this operation is repeated under low humidity over a long period of time.

  That is, under low humidity where the rising of the triboelectric charge amount is slow, the triboelectric charge amount hardly increases in the continuous printing operation of about 5 sheets. In this state, since the adhesion between the toner particles and the metal compound fine particles is very weak, the metal compound fine particles are detached from the surface of the toner particles and transferred to the toner carrier. When the amount of transfer increases, the surface of the toner carrier is contaminated, and normal charging of the toner is hindered. For example, in the frictional charging between the metal compound fine particles and the toner carrier, when the metal compound fine particles exhibit the opposite polarity to that of the toner, only the toner particles are consumed in the development process, so the metal compound remaining on the toner carrier The fine particles increase with printing, the amount of triboelectric charge of the toner becomes abnormally low, and the decrease in image density and the deterioration of fog become remarkable.

  In contrast, if the metal compound fine particles exhibit the same charge polarity as that of the toner in frictional charging with the toner carrier, even if the metal compound fine particles are detached from the toner particle surface and migrate to the toner carrier, the development is continued. Since it is consumed together with the toner in the process, accumulation of metal compound fine particles on the toner carrier is suppressed, abnormal frictional charging of the toner is suppressed, and a high-definition image can be stably maintained over a long period of time.

  Furthermore, the absolute value of the triboelectric charge amount of the metal compound fine particles in the triboelectric charge between the metal compound fine particles and the toner carrier according to the present invention may be 0.5 (mC / kg) or more and 20 (mC / kg) or less. is important. If it is less than 0.5 (mC / kg), the triboelectric charge amount is too small to be developed in the development process, and therefore it is not easy to prevent accumulation on the toner carrier during durability. On the other hand, if it exceeds 20 (mC / kg), the adhesion increases due to dielectric polarization, which is not preferable. For example, since negatively chargeable toner is used in the examples of the present application, the triboelectric charge amount of metal compound fine particles having the same polarity is preferably −20 (mC / kg) or more and −0.5 (mC / kg) or less. It will be.

  Here, the charging property of the metal compound fine particles can be performed by the following method.

  The metal compound fine particles are put in the cartridge for the LBP printer to be used, set in the printer main body, and the metal compound fine particles are applied on the toner carrier using the pre-rotation before the image forming process. The surface of the toner carrier to which the metal compound fine particles are applied is sucked with a Faraday-Cage shown in FIG. The Faraday gauge is a coaxial and double cylinder, and the inner cylinder and the outer cylinder are insulated. If a charged body having a charge amount Q is put in the inner cylinder, it is as if a metal cylinder having an electric amount Q is present due to electrostatic induction. This induced charge amount was measured by KEITHLEY 616 DIGITAL ELECTROMETER to determine the triboelectric charge amount of the metal compound fine particles on the surface of the toner carrier.

Further, even if the absolute value of the triboelectric charge of the metal compound fine particles in the triboelectric charge with the toner carrier is within the above range, if the absolute value of the triboelectric charge amount of the toner present at the same time is too low, the metal compound fine particles are separated from the toner. It is difficult to obtain an image quality improvement effect because it is easily released. On the other hand, when the amount of triboelectric charge of the toner is too high, the metal compound fine particles having the same polarity are easily released from the toner due to Coulomb repulsion. Therefore, in the frictional charging between the metal compound fine particles and the toner carrier, the frictional charge amount indicated by the metal compound fine particles is A, and in the frictional charging between the toner and the toner carrier, the frictional charge amount indicated by the toner is B. When
0.05 ≦ | A / B | ≦ 2
It is more preferable that

In the present invention, the specific surface area (cm ² / cm ³ ) of the metal compound fine particles is more preferably 5 × 10 ⁵ or more and 100 × 10 ⁵ or less.

  The inventors have made various additional tests to improve the technology disclosed so far. 1) It is difficult to stably obtain sufficient performance as an image quality improver. 2) Contamination of the toner carrier. Various problems, such as a lot of image quality degradation due to, became clear. Therefore, as a result of repeated investigations on the problem 1), some knowledge was obtained, and based on this, it became clear that the problem solving means 2) could be reached in addition to 1).

  Therefore, as an important technical point directly related to the present invention, the adhesion between the metal compound fine particles and the toner particles and between the metal compound fine particles and the toner carrier will be considered.

  The number of contacts is 1 when a particle that is generally assumed to be spherical contacts a member that is assumed to be substantially planar. This also applies to the contact between the metal compound fine particles and the toner particles or toner carrier. Therefore, if irregularities are formed on the surface of the metal compound fine particles, the number of contacts between the metal compound fine particles and the toner particles can be increased, and the image characteristics can be improved. In addition to this, the contact point with the toner carrier also increases, so that it acts favorably when the excess charge generated by the exchange with the toner is quickly transferred to the toner carrier and reduces the interaction with the toner carrier. In addition, the adhesiveness to the toner carrying member is also lowered due to the release effect of the convex portions. Furthermore, when the direct injection charging mechanism is adopted, the number of contact points with the charging member can be increased, so that the injection charging property is improved, which is highly preferable.

  In other words, the formation of a large number of irregularities on the surface of the metal compound fine particles not only improves the image quality due to the interaction with the toner, but also suppresses the adhesion to the toner carrier and reduces the image quality due to toner carrier contamination. It can be said that this is an important technology that leads to the prevention of accidents.

As an index of the number of irregularities on the particle surface, the specific surface area of the particle powder is usually used. However, the specific surface area generally used is the surface area per unit mass, as can be seen from the unit “cm ² / g”, and it is not easy to compare or optimize with materials having different specific gravities in the discussion using this numerical value. .

Therefore, the present inventors adopt a unit of “cm ² / cm ³ ” which is a physical property corresponding to the surface area per fine particle as the specific surface area, and the specific surface area of the metal compound fine particles and the initial image characteristics, that is, the image quality improving effect, In addition, the present inventors studied diligently about the relationship with the deterioration of image quality accompanying the durability, that is, the toner carrier contamination.

As a result, it was found that when the specific surface area (cm ² / cm ³ ) of the metal compound fine particles contained in the toner used is 5 × 10 ⁵ or more and 100 × 10 ⁵ or less, image characteristics and durability are greatly improved. It was. In particular, the rise in the triboelectric charge amount was slow, and the toner and the free metal fine particles showed good durability even under low humidity where the toner carrier was easily contaminated.

Here, when the specific surface area is larger than 100 × 10 ⁵ , that is, when there are too many surface protrusions, the adhesion to the toner carrier tends to become strong, and rather the image quality deterioration due to contamination becomes conspicuous. On the other hand, if it is less than 5 × 10 ⁵ , the interaction with the toner is weakened, and the image quality improvement effect is weakened. Preferably, the initial image characteristics and durability are further improved by setting them to 10 × 10 ⁵ or more and 80 × 10 ⁵ or less, more preferably 12 × 10 ⁵ or more and 40 × 10 ⁵ or less.

  Here, the specific surface area of normal fine particles will also be described.

In the case of fine particles that can generally approximate a spherical shape, if the particle radius is r (cm),
Surface area per particle = 4 × π × r ²
Volume per fine particle = (4/3) x π x r ³
The surface area per unit volume is as follows:
Surface area per fine particle / volume per fine particle = 3 / r
And using a volume-based median diameter (D ₅₀ ; unit μm),
r (cm) = D ₅₀ (μm) / 2 × 10 ⁴
Therefore, specific surface area (cm ² / cm ³ ) = 6 × 10 ⁴ / D ₅₀
It becomes. Note that even a slightly irregular fine particle is about 10 × 10 ⁴ / D ₅₀ . Here, since the median diameter (D ₅₀ ) of the metal compound fine particles according to the present invention is 0.4 to 4.0 μm, the fine particles having ordinary surface properties are at most about 2.5 × 10 ⁵ . It can only have a specific surface area.

  However, with such a specific surface area, the number of contact points with the toner particles or the charging member is insufficient, and the effect as seen in the configuration of the present invention cannot be expected.

According to the study by the present inventors,
A sufficient effect was observed when the surface area per unit volume was 5 × 10 ⁵ / D ₅₀ ≦.

on the other hand,
When the surface area per unit volume is 100 × 10 ⁵ / D ₅₀ <the surface irregularity is too much compared to the particle size, the interaction with the toner particles becomes too strong and the fog and the like tend to deteriorate. Therefore, it is not preferable.

  In the present invention, the specific surface area of the metal compound fine particles was determined as follows.

First, according to the BET method, nitrogen gas was adsorbed on the sample surface using a specific surface area measuring device “Gemini 2375 Ver. 5.0” (manufactured by Shimadzu Corporation), and the BET specific surface area (cm ² ) was measured using the BET multipoint method. / G).

Next, the true density (g / cm ³ ) is obtained using a dry automatic densimeter “Acpyc 1330” (manufactured by Shimadzu Corporation). At this time, a 10 cm ³ sample container is used, and as a sample pretreatment, helium gas purge is performed 10 times at a maximum pressure of 19.5 psig. After that, as a pressure equilibrium judgment value as to whether or not the pressure in the container has reached equilibrium, the pressure fluctuation in the sample chamber is 0.0050 / min as a guide. Start and automatically measure true density. The measurement is performed 5 times, the average value is obtained, and the true density is obtained.

Here, the specific surface area of the powder is obtained as follows.
Specific surface area (cm ² / cm ³ ) = BET specific surface area (cm ² / g) × true density (g / cm ³ )

Further, the metal compound fine particles have a volume-based median diameter (D ₅₀ ) of 0.4 μm or more and 4.0 μm or less and less than the weight average particle diameter of the toner, and D ₉₀ is larger than 0.5 μm and 6.0 μm or less. Conductive fine particles are preferred.

In general, the greater the difference in particle size between particles, the stronger the adhesive force due to the interaction between particles. One of the expected effects of the metal compound fine particles according to the present invention is to improve the triboelectric charging characteristics by contact friction with the toner, so that the action is difficult if the metal compound fine particles and the toner particles are strongly adhered. It becomes. The toner of the present invention has a mass average particle diameter of 3.0 μm to 12.0 μm in order to achieve high image quality, but the appropriate D ₅₀ of the metal compound fine particles is 0.4 μm or more. Metal compound fine particles having a D ₅₀ of less than 0.4 μm are difficult to separate from toner particles, and improvement in frictional charging characteristics cannot be expected. For example, sufficient image density cannot be obtained. Further, once the stool is separated from the toner particles, it adheres strongly to the toner carrier, so that contamination is easily increased.

On the other hand, the interaction between the toner when D ₅₀ is increased is weakened, the effect of improving the friction charging properties reduced. When a metal compound D ₅₀ of the particles is on a mass average particle size or less of the toner, in addition to the effect of the interaction is hardly observed, under development field will act as an electrode, so rather inhibit the movement of the toner Therefore, the fog is deteriorated or the resolving power is decreased. Accordingly, it is preferably 4.0 μm or less, and more preferably D ₅₀ is 0.5 μm or more and 3.5 μm or less. For this reason, it is necessary to reduce the number of particles having a large particle diameter. If D ₁₀ and D ₉₀ on a volume basis are used as an index of particle size distribution, D ₉₀ is preferably 6.0 μm or less, and more preferably 4.0 μm or less. It can be said.

In addition, it is more preferable if D ₁₀ is less than 3.5 μm. In the same meaning, the particle size distribution of the metal compound fine particles is preferably such that the number of particles having very small particle diameter is small, and D ₁₀ is preferably 0.3 μm or more, more preferably 0.4 μm or more. In addition further preferably D ₉₀ of greater than 0.5μm in.

Here, D ₁₀ , D ₅₀ and D ₉₀ of the metal compound fine particles are measured as follows.

  A liquid module is attached to a laser diffraction type particle size distribution measuring apparatus “LS-230 type” (manufactured by Coulter), and a particle size of 0.04 to 2000 μm is set as a measurement range, and D10 and D50 of particles are obtained by a volume-based particle size distribution obtained. , D90 is calculated. In the measurement, about 10 mg of particles are added to 10 ml of methanol and dispersed for 2 minutes with an ultrasonic disperser, and then measured under the conditions of a measurement time of 90 seconds and a single measurement.

  The metal compound fine particles according to the present invention are preferably nonmagnetic.

  When magnetic compound fine particles are added to magnetic toner, for example, the fine particles released from the toner often adhere to the toner carrier and become contaminated, and it is durable only by strictly controlling the specific surface area and particle size distribution. It may not be possible to completely prevent adverse effects on sex.

The preferred volume resistance of the metal compound fine particles according to the present invention is 1 × 10 ⁻¹ to 1 × 10 ⁹ Ωcm. If it exceeds 1 × 10 ⁹ Ωcm, the effect of stabilizing the triboelectric charge amount in a low-humidity environment cannot be expected so much, and when the direct injection charging mechanism in the simultaneous development cleaning system is adopted, the injection charging property is improved. Not expected. On the other hand, if it is less than 1 × 10 ⁻¹ Ωcm, the triboelectric charging characteristics of the toner under high humidity are hindered, and in addition to a decrease in developability, fogging and transferability are deteriorated.

  Here, the resistance of the particles is measured as follows.

A cylindrical metal cell is filled with a sample, electrodes are arranged up and down so as to contact the sample, and a load of 686 kPa (7 kgf / cm ² ) is applied to the upper electrode. In this state, a voltage V is applied between the electrodes, and the resistance (volume resistivity RV) of the present invention is measured from the current I (A) flowing at that time. At this time, when the electrode area is S (cm ² ) and the sample thickness is M (cm), RV (Ωcm) = 100 V × S (cm ² ) / I (A) / M (cm).

In the present invention, the contact area between the electrode and the sample was 2.26 cm ^2, and the measurement was performed at a voltage V = 100V.

  Examples of the metal compound fine particles in the present invention include metal fine powders such as copper, gold, silver, aluminum and nickel; zinc oxide, titanium oxide, tin oxide, aluminum oxide, indium oxide, silicon oxide, magnesium oxide, barium oxide, Metal oxides such as molybdenum oxide, iron oxide, and tungsten oxide; metal compounds such as molybdenum sulfide, cadmium sulfide, and potassium titanate, or conductive fine powders of these composite oxides can be used.

  Among these, the inclusion of at least one oxide selected from zinc oxide, tin oxide, and titanium oxide allows the resistance of the metal compound fine particles to be set low, is white or light, and is transferred onto the transfer material. It is preferable in that the metal compound fine particles are not noticeable as fog.

  In addition, for the purpose of controlling the resistance value of metal compound fine particles, metal oxide fine particles containing elements such as antimony, aluminum, tungsten, and phosphorus, and fine particles having a conductive material on the surface are also used as metal compound fine particles. Can be used. For example, zinc oxide fine particles containing an aluminum element, tin oxide fine particles containing an antimony element, and the like.

  However, resistance control by introducing antimony element generally increases the bluish black color of the powder, and therefore, when developed on white paper, the background which is a non-printing portion is stained, which is not preferable.

  In addition, it is preferable that the metal compound fine particles contain at least tin oxide, and it is also preferable that a higher content of the metal compound particles is preferable because adhesion to the toner carrier is moderately suppressed. Although it seems to be based on the interaction between the HOMO-LUMO of the resin compound covering the toner carrier, the tin oxide conductor and the valence band, the details are unknown.

  However, resistance control is not sufficient with fine metal compound fine particles containing about 100% by mass of ordinary tin oxide.

  Therefore, in the present invention, it is more preferable to use reduction-treated tin oxide as the metal compound fine particles, which has a high direct injection charging speed, a light color, and capable of appropriate resistance control.

  Incidentally, the tin oxide subjected to the reduction treatment is disclosed in JP-A-6-345429. However, the content relates to a material technology for the purpose of imparting conductivity to the polymer by internally added dispersion. The present invention improves powder characteristics, image characteristics, and even ecology by externally mixing with special powder and using it in a unique image forming system. Japanese Patent Application Laid-Open No. 6-345429 The technical contents of the invention are completely different from each other in terms of the purpose of the invention and the mode of use.

  It is also preferable from the viewpoint of preventing contamination that the metal compound fine particles are subjected to an appropriate surface treatment to weaken the adhesion to the toner carrier. As the treatment agent for the surface treatment, a silicon compound is preferable because of its high releasability.

The appropriate content of the metal compound fine particles in the toner of the present invention depends on the toner specific gravity. When the specific gravity of the toner is high, the surface area per unit weight of the toner is small, so the appropriate content is small. Conversely, when the specific gravity of the toner is small, the appropriate content increases. In other words, the proper content and the specific gravity of the toner are in an inversely proportional relationship, and therefore the product of both values is preferably within a certain range. Specifically, when the content of the metal compound fine particles with respect to the toner is X (mass%) and the toner specific gravity is Y (g / cm ³ ),
0.5 ≦ X × Y ≦ 6.0
It is preferable to satisfy the relationship. When X × Y <0.5, the content of the metal compound fine particles is small, and it is difficult to obtain a sufficient addition effect. On the other hand, if 6.0 <X × Y, the amount of metal compound fine particles released from the toner increases, which tends to promote contamination of the toner carrier, which is not preferable.

  In the toner used in the present invention, an inorganic fine powder having an average primary particle size of 4 to 80 nm is preferably added as a fluidizing agent and a transfer aid. Inorganic fine powder is added to improve toner fluidity, uniform triboelectric charge amount of toner particles, and improve transferability. However, the triboelectric charge amount of toner can be improved by hydrophobizing inorganic fine powder. It is also a preferable form to provide functions such as adjustment of resistance and improvement of durability stability.

  When the average primary particle size of the inorganic fine powder is larger than 80 nm, the image density is lowered, and it is difficult to stably obtain a good image. In addition, good toner fluidity cannot be obtained, and the charge imparted to the toner particles tends to be insufficient. Therefore, the amount of release of the metal compound fine particles tends to increase, fogging due to toner carrier contamination, and transfer residual toner. Becomes easier to see. For this reason, in the cleanerless system, the charging member is significantly contaminated. Therefore, even if the metal compound fine particles according to the present invention are used, it is difficult to avoid a decrease in charging property. On the other hand, when the average primary particle size of the inorganic fine powder is smaller than 4 nm, the cohesiveness of the inorganic fine powder is increased, and the aggregate has a wide particle size distribution with strong cohesiveness that is difficult to be broken by the pulverization treatment instead of the primary particles. It tends to behave as an aggregate and easily causes image defects due to development of aggregates, damage to the image carrier or developer carrier, and the like. In order to make the triboelectric charge amount distribution of the toner particles more uniform, the average primary particle size of the inorganic fine powder is more preferably 6 to 70 nm.

  In the present invention, the measurement method of the average primary particle size of the inorganic fine powder is a photograph of the toner magnified by a scanning electron microscope, and the inorganic fine powder is further analyzed by an elemental analysis means such as XMA attached to the scanning electron microscope. While contrasting the photograph of the toner mapped with the contained element, 100 or more primary particles of the inorganic fine powder that are attached to or separated from the toner surface can be measured to obtain the number average particle diameter.

  As the inorganic fine powder used in the present invention, silica, alumina, titanium oxide, or a composite oxide thereof can be used.

For example, as silica, so-called silicate fine powder, both so-called dry process produced by vapor phase oxidation of silicon halides or dry silica called fumed silica, and so-called wet silica produced from water glass, etc. Can be used, but dry silica is preferred because it has few silanol groups on the surface and in the silica fine powder, and few production residues such as Na ₂ O and SO ³⁻ . In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.

  The addition amount of the inorganic fine powder having an average primary particle size of 4 to 80 nm is preferably 0.1 to 3.0% by mass with respect to the toner, and the effect is sufficient when the addition amount is less than 0.1% by mass. However, if it exceeds 3.0% by mass, the fixing property is deteriorated.

  Here, although the inorganic fine powder exceeds the target range of the present invention, it is preferably a hydrophobized product in consideration of the characteristics in a high temperature and high humidity environment. When the inorganic fine powder mixed with the toner absorbs moisture, the triboelectric charge amount of the toner is remarkably reduced, and the toner is likely to scatter.

  As treatment agents for hydrophobizing treatment, treatment agents such as silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, and organic titanium compounds may be used alone or You may process together.

  Among these, those treated with silicone oil are preferable, and more preferably, the inorganic fine powder is treated with silicone oil at the same time or after hydrophobizing with a silane compound, and then treated with silicone oil. It is good for keeping the amount high and preventing toner scattering.

  The conditions for hydrophobizing the inorganic fine powder are as follows. For example, a silylation reaction is performed with a silane compound as a first-stage reaction, and silanol groups are eliminated by chemical bonding, and then a hydrophobic thin film is formed on the surface with silicone oil as a second-stage reaction.

The silicone oil preferably has a viscosity at 25 ° C. of 10 to 200,000 mm ² / s, and more preferably 3,000 to 80,000 mm ² / s. If it is less than 10 mm ² / s, the inorganic fine powder is not stable and the image quality tends to deteriorate due to heat and mechanical stress. If it exceeds 200,000 mm ² / s, uniform processing tends to be difficult.

  As the silicone oil used, 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.

  As a method for treating the silicone oil, for example, the inorganic fine powder treated with the silane compound and the silicone oil may be directly mixed using a mixer such as a Henschel mixer, or the silicone oil is sprayed onto the inorganic fine powder. A method may be used.

  Alternatively, after dissolving or dispersing silicone oil in an appropriate solvent, inorganic fine powder may be added and mixed to remove the solvent. A method using a sprayer is more preferable in that the formation of inorganic fine powder aggregates is relatively small.

  The treatment amount of the silicone oil is 1 to 23 parts by mass, preferably 5 to 20 parts by mass with respect to 100 parts by mass of the inorganic fine powder. If the amount of silicone oil is too small, good hydrophobicity cannot be obtained, and if it is too large, problems such as fogging occur.

  In the configuration of the present invention, it is also preferable to use a simultaneous development cleaning system and a magnetic toner in combination. This is because if the magnetic restraining force is used, it is easy to collect the transfer residual toner in the developing region between the toner carrier and the latent image carrier.

  When a magnetic toner is employed as the toner according to the present invention, magnetic iron oxide may be used as a colorant. As a material that can be used in this case, examples of magnetic iron oxide include iron oxides such as magnetite, maghemite, and ferrite. And those containing non-ferrous elements on or inside the magnetic iron oxide are preferred.

  Moreover, as said non-ferrous element, it is preferable to contain 0.05-10 mass% on the basis of an iron element. Especially preferably, it is 0.1-5 mass%.

  Moreover, it is preferable that these magnetic iron oxides contain 20-200 mass parts with respect to 100 mass parts of binder resin. More preferably, 50 to 120 parts by mass are contained.

  The different element is preferably an element selected from magnesium, aluminum, silicon, phosphorus, and sulfur. The following lithium, beryllium, boron, germanium, titanium, zirconium, tin, lead, zinc, calcium, barium, scandium, vanadium, chromium, manganese, cobalt, copper, nickel, gallium, cadmium, indium, silver element, Examples of the metal include palladium, gold, mercury, platinum, tungsten, molybdenum, niobium, osmium, strontium, yttrium, and technetium.

These magnetic iron oxides preferably have a number average particle diameter of 0.05 to 1.0 μm, more preferably 0.1 to 0.5 μm. Magnetic iron oxide having a BET specific surface area of ² to 40 m ² / g (more preferably 4 to ²⁰ m ² / g) is preferably used. There is no restriction | limiting in particular in a shape, The thing of arbitrary shapes is used. As magnetic characteristics, under a magnetic field of 795.8 kA / m, the saturation magnetization is 10 to 200 Am ² / kg (more preferably 70 to 100 Am ² / kg), and the residual magnetization is 1 to 100 Am ² / kg (more preferably 2 ˜20 Am ² / kg) and those having a coercive force of 1 to 30 kA / m (more preferably 2 to 15 kA / m) are preferably used.

Further, when a magnetic toner is used as the toner according to the present invention, the density of the magnetic toner is preferably 1.3 to 2.2 g / cm ³ . Furthermore, it is preferable that it is the range of 1.5-2.0 g / cm < ³ >. The mass (density) of the magnetic toner correlates with the magnetic force, electrostatic force, and gravity acting on the magnetic toner particles. When the density of the magnetic toner is within this range, the action of magnetic iron oxide is appropriate. It has a good balance with magnetic force and can exhibit excellent developing power.

On the other hand, when the density of the magnetic toner is less than 1.3 g / cm ³ , the magnetic force is low because the action of magnetic iron oxide on the magnetic toner is weak. For this reason, the electrostatic force for flying to the photosensitive drum at the time of development is superior, resulting in an excessive development state, leading to an increase in fog and consumption. On the other hand, when the magnetic toner density is over 2.2 g / cm ³ , the action of magnetic iron oxide on the magnetic toner becomes stronger and the magnetic force becomes stronger than the electrostatic force, and the strong magnetic force action is large and the specific gravity is also heavy. Therefore, it is difficult to fly from the sleeve at the time of development, resulting in a state of insufficient development, leading to low image density and image deterioration.

  In some cases, the magnetic iron oxide used in the magnetic toner of the present invention may be treated with a silane coupling agent, a titanium coupling agent, titanate, aminosilane, or the like.

  The toner of the present invention will be further described.

  The toner of the present invention preferably has a glass transition temperature (Tg) of 45 to 80 ° C., and more preferably 50 to 70 ° C. from the viewpoints of storage stability and fixability. If Tg is lower than 45 ° C., it may cause toner deterioration in a high temperature atmosphere or offset during fixing. On the other hand, when Tg exceeds 80 ° C., fixability tends to decrease.

  As a method for measuring the glass transition temperature of the toner of the present invention, a differential thermal analysis measurement device (DSC measurement device), DSC-7 (manufactured by Perkin Elmer), EXSTAR6000, SSC / 5200 (manufactured by Seiko Instruments Inc.), DSC2920MDSC ( TA Instruments, etc.) can be used under the following conditions.

<Method of measuring glass transition temperature of toner>
Sample: 0.5-2 mg, preferably 1 mg
Temperature curve: Temperature increase I (20 ° C. to 180 ° C., temperature increase rate 10 ° C./min)
Temperature drop I (180 ° C. to 10 ° C., temperature drop rate 10 ° C./min)
Temperature increase II (10 ° C to 180 ° C, temperature increase rate 10 ° C / min)
Measurement method: Place the sample in an aluminum pan, and use an empty aluminum pan as a reference. Suck
The glass transition point Tg was defined as the intersection between the line at the midpoint of the base line before and after the thermal peak and the differential thermal curve.

  The binder resin component used in the present invention has a Mn (number average molecular weight) of 3000 to 20000 and a Mw (weight average molecular weight) of 50,000 to 500,000 in the molecular weight measured by GPC of the THF soluble component. It is preferable that it is the range of these. Within this range, the balance between fixability and durability is very good.

  These binder resin components can be mixed and dispersed in advance when the toner is produced. By mixing the wax component in advance, phase separation in the micro region is relaxed, and a good dispersion state is obtained.

  In the present invention, the molecular weight distribution of the toner or binder resin by GPC using THF (tetrahydrofuran) as a solvent is measured under the following conditions.

The column is stabilized in a 40 ° C. heat chamber, and THF as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml per minute, and about 100 μl of a sample THF solution is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, a product having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko is used, and at least about 10 standard polystyrene samples are suitably used. . An RI (refractive index) detector is used as the detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, combinations of shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko KK and TSKgel G1000H (H _XL ), G2000H (H _XL ), G3000H (H _XL ) manufactured by Tosoh Corporation , G4000H (H _XL ), G5000H (H _XL ), G6000H (H _XL ), G7000H (H _XL ), and TSK guard column.

  The sample is prepared as follows.

  Put the sample in THF, leave it for several hours, then shake well and mix well with THF (until the sample is no longer united) and let stand for more than 12 hours. At this time, the sample is left in THF for 24 hours or longer. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5 manufactured by Tosoh Corp., Excro Disc 25CR manufactured by Gelman Science Japan Co., Ltd., etc.) can be used. This is a measurement sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

  The types of toner binder resins in the present invention include styrene resins, styrene copolymer resins, polyester resins, polyol resins, polyvinyl chloride resins, phenol resins, natural modified phenol resins, natural resin modified maleic resins, acrylic resins. Examples include resins, methacrylic resins, polyvinyl acetate, silicone resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone indene resins, and petroleum resins.

  As a comonomer for the styrene monomer of the styrene copolymer, styrene derivatives such as vinyltoluene, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, acrylic Acrylic acid ester such as phenyl acid; Methacrylic acid ester such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate; Maleic acid; Double such as butyl maleate, methyl maleate, dimethyl maleate Dicarboxylic acid ester having a bond; acrylamide, acrylonitrile, methacrylonitrile, butadiene; vinyl chloride; vinyl ester such as vinyl acetate and vinyl benzoate; ethylene, propylene, butylene Such ethylenic olefins, vinyl methyl ketone, such as vinyl vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl propionate ether. These vinyl monomers are used alone or in combination of two or more.

  The toner in the present invention preferably has an acid value in the range of 1 to 100 mgKOH / g. Especially preferably, it is 1-70 mgKOH / g. If it exceeds 70 mgKOH / g, the triboelectric charge amount under high humidity is insufficient, and if it is less than 1 mgKOH / g, the triboelectric charging rate under low humidity becomes slow.

  To adjust the acid value of the toner, for example, acrylic resin such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, cinnamic acid, vinylacetic acid, isocrotonic acid, and angelic acid can be used as a binder resin monomer. Acids and their α- or β-alkyl derivatives, fumaric acid, maleic acid, citraconic acid, alkenyl succinic acid, itaconic acid, mesaconic acid, dimethyl maleic acid, dimethyl fumaric acid and the like, and monoester derivatives or anhydrides thereof A desired polymer can be prepared by copolymerizing such monomers alone or in combination with other monomers. Among these, it is particularly preferable to use a monoester derivative of an unsaturated dicarboxylic acid in order to control the acid value.

  More specifically, for example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate, monophenyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate Monoesters of α, β-unsaturated dicarboxylic acids such as: monobutyl n-butenyl succinate, monomethyl n-octenyl succinate, monoethyl n-butenylmalonate, monomethyl n-dodecenyl glutarate, monobutyl n-butenyl adipate And monoesters of alkenyldicarboxylic acid such as

  The carboxyl group-containing monomer as described above may be added in an amount of 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, with respect to 100 parts by mass of all monomers constituting the binder resin.

  Examples of the polymerization method that can be used as a method for synthesizing the binder resin of the present invention include a solution polymerization method, an emulsion polymerization method, and a suspension polymerization method.

  Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is performed using a water-soluble polymerization initiator. In this method, the reaction heat can be easily adjusted, and the termination reaction rate is low because the phase in which the polymerization is carried out (the oil phase consisting of the polymer and the monomer) and the aqueous phase are separate, resulting in a high polymerization rate. A product having a high degree of polymerization is obtained. Furthermore, the reason is that the polymerization process is relatively simple, and that the polymerization product is fine particles, so that it can be easily mixed with colorants, charge control agents and other additives in the production of toner. Therefore, there is an advantage as a method for producing a binder resin for toner.

  However, the added polymer is likely to be impure due to the added emulsifier, and an operation such as salting out is necessary to take out the polymer. Suspension polymerization is convenient to avoid this inconvenience.

  In suspension polymerization, it is good to carry out by 100 mass parts or less (preferably 10-90 mass parts) of monomers with respect to 100 mass parts of aqueous solvents. Examples of the dispersant that can be used include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like, and generally 0.05 to 1 part by mass with respect to 100 parts by mass of the aqueous solvent. The polymerization temperature is suitably 50 to 95 ° C., but is appropriately selected depending on the initiator used and the target polymer.

  The binder resin used in the present invention is preferably produced by using a polyfunctional polymerization initiator alone or in combination with a monofunctional polymerization initiator as exemplified below.

  Specific examples of the polyfunctional polymerization initiator having a polyfunctional structure include 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,3-bis- (t-butylperoxy Isopropyl) benzene, 2,5-dimethyl-2,5- (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, tris- (t-butyl) Peroxy) triazine, 1,1-di-t-butylperoxycyclohexane, 2,2-di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester , Di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, di-t-butylperoxytrimethyladipate, 2,2-bis- ( , 4-di-t-butylperoxycyclohexyl) propane, 2,2-t-butylperoxyoctane and various polymer oxides, etc., a functional group having a polymerization initiating function such as two or more peroxide groups in one molecule. And a polyfunctional polymerization initiator having a peroxide group in one molecule such as diallyl peroxydicarbonate, t-butylperoxymaleic acid, t-butylperoxyallylcarbonate and t-butylperoxyisopropyl fumarate And a polyfunctional polymerization initiator having both a functional group having a polymerization initiating function and a polymerizable unsaturated group.

  Of these, more preferred are 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, di-t-butylperoxy. Hexahydroterephthalate, di-t-butylperoxyazelate and 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, and t-butylperoxyallyl carbonate.

  These polyfunctional polymerization initiators are preferably used in combination with a monofunctional polymerization initiator in order to satisfy various performances required as a binder for toner. In particular, it is preferable to use in combination with a polymerization initiator having a decomposition temperature of a half-life of 10 hours which is lower than the decomposition temperature for obtaining a half-life of 10 hours of the polyfunctional polymerization initiator.

  Specifically, benzoyl peroxide, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-di (t-butylperoxy) valerate, dichroic Organic peroxides such as milperoxide, α, α'-bis (t-butylperoxydiisopropyl) benzene, t-butylperoxycumene, di-t-butylperoxide, azobisisobutyronitrile, diazoamino Examples include azo and diazo compounds such as azobenzene.

  These monofunctional polymerization initiators may be added to the monomer at the same time as the polyfunctional polymerization initiator, but in order to keep the efficiency of the polyfunctional polymerization initiator appropriate, in the polymerization step, It is preferably added after the half-life indicated by the polyfunctional polymerization initiator has elapsed.

  These initiators are preferably used in an amount of 0.05 to 2 parts by mass with respect to 100 parts by mass of the monomer from the viewpoint of efficiency.

  It is also preferable that the binder resin is crosslinked with a crosslinking monomer.

  As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. Specific examples include aromatic divinyl compounds (eg, divinylbenzene, divinylnaphthalene, etc.); diacrylate compounds linked by alkyl chains (eg, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4 -Butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and acrylates of the above compounds replaced with methacrylate); alkyl chain containing an ether bond Diacrylate compounds (eg, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, Ethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds in place of methacrylate); diacrylate compounds linked by a chain containing an aromatic group and an ether bond (eg, polyoxyethylene) (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and methacrylates of the above compounds Furthermore, polyester-type diacrylate compounds (for example, trade name MANDA (Nippon Kayaku)) are mentioned. As polyfunctional crosslinking agents, pentaerythritol acrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds are replaced with methacrylate. Triallyl cyanurate, triallyl trimellitate; and the like.

  These crosslinking agents are preferably used in the range of 0.00001 to 1 part by mass, preferably 0.001 to 0.05 part by mass, with respect to 100 parts by mass of the other monomer components.

  Among these crosslinkable monomers, aromatic divinyl compounds (especially divinylbenzene), diethers linked by a chain containing an aromatic group and an ether bond are preferably used from the viewpoint of toner fixing properties and offset resistance. Examples include acrylate compounds.

  As other synthesis methods, a bulk polymerization method and a solution polymerization method can be used. However, in the bulk polymerization method, a polymer having a low molecular weight can be obtained by polymerizing at a high temperature to increase the termination reaction rate, but there is a problem that the reaction is difficult to control. In that respect, the solution polymerization method can easily obtain a polymer with a desired molecular weight under mild conditions by utilizing the difference in chain transfer of radicals by a solvent and adjusting the amount of initiator and reaction temperature. Is preferable. In particular, a solution polymerization method under a pressurized condition is also preferable in that the amount of the initiator used is minimized and the influence of the remaining initiator is minimized.

  The composition of the polyester resin used in the present invention is as follows.

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

（式中Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０〜１０である。）

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

  And diols represented by the formula (F);

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

  Moreover, it is preferable to use together the trihydric or more alcohol component and trivalent or more acid component which work as a crosslinking component.

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

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

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

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

  When a polyester resin is used as the binder resin, the alcohol component used is 40 to 60 mol%, preferably 45 to 55 mol%, and the acid component is preferably 60 to 40 mol%, preferably 55 to 45 mol%. Moreover, it is preferable that the polyvalent component more than trivalence is 5-60 mol% in all the components.

  The polyester resin can also be obtained by a generally known condensation polymerization.

  Examples of the wax used in the toner of the present invention are as follows. For example, low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxide of aliphatic hydrocarbon wax such as oxidized polyethylene wax Or block copolymers thereof; plant waxes such as candelilla wax, carnauba wax, wax wax, jojoba wax; animal waxes such as beeswax, lanolin, spermaceti; mineral systems such as ozokerite, ceresin, petrolactam Waxes; waxes mainly composed of aliphatic esters such as montanic acid ester wax and castor wax; those obtained by partially or fully deoxidizing aliphatic esters such as deoxidized carnauba wax . Further, saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a long-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinal acid; stearyl alcohol Saturated alcohol such as eicosyl alcohol, behenyl alcohol, cannavir alcohol, seryl alcohol, melyl alcohol, or alkyl alcohol having a long chain alkyl group; polyhydric alcohol such as sorbitol; linoleic acid amide, oleic acid amide, lauric acid Aliphatic amides such as acid amides; saturated aliphatic bisamides such as methylene bisstearic acid amide, ethylene biscapric acid amides, ethylene bislauric acid amides, hexamethylene bisstearic acid amides; Unsaturated fatty acid amides such as inamide, hexamethylenebisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, Aromatic bisamides such as N'-distearylisophthalamide; aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as metal soap); aliphatic hydrocarbons Wax grafted with a vinyl monomer such as styrene or acrylic acid; partially esterified product of fatty acid and polyhydric alcohol such as behenic acid monoglyceride; hydroxyl group obtained by hydrogenating vegetable oil Methyl ester compounds It is.

  Specific examples of the wax include Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industries), high wax 400P, 200P, 100P, 410P, 420P, 320P. , 220P, 210P, 110P (Mitsui Chemicals), Sazol H1, H2, C80, C105, C77 (Schumann Sazol), HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP -12 (Nippon Seiki Co., Ltd.), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark), Unicid (registered trademark) 350, 425, 550, 700 (Toyo Petrolite), Kirou , Beeswax, rice wax, candelilla wax, carnauba wax (entered at Celerica NODA) Possible), and the like.

  In addition, these waxes have a sharp molecular weight distribution using a press sweating method, a solvent method, a recrystallization method, a vacuum distillation method, a supercritical gas extraction method or a melt liquid crystal deposition method, a low molecular weight solid fatty acid, a low molecular weight A solid alcohol, a low molecular weight solid compound, and other impurities are preferably used.

  The toner of the present invention preferably contains a charge control agent.

  Examples of the toner that controls the negative charge include the following compounds.

  Organic metal complexes and chelate compounds are effective, and examples include monoazo metal compounds, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and metal complexes of aromatic dicarboxylic acids. Others include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives of bisphenol.

  Among these, an azo metal compound represented by the following formula (I) is preferable.

〔式中、Ｍは配位中心金属を表し、Ｓｃ，Ｔｉ，Ｖ，Ｃｒ，Ｃｏ，Ｎｉ，Ｍｎ又はＦｅ等が挙げられる。Ａｒはアリール基であり、フェニル基、ナフチル基の如きアリール基であり、置換基を有してもよい。この場合の置換基としては、ニトロ基、ハロゲン基、カルボキシル基、アニリド基及び炭素数１〜１８のアルキル基、炭素数１〜１８のアルコキシ基がある。Ｘ，Ｘ’，Ｙ及びＹ’は−Ｏ−，−ＣＯ−，−ＮＨ−，−ＮＲ−（Ｒは炭素数１〜４のアルキル基）である。Ｃ⁺はカウンターイオンを示し、水素、ナトリウム、カリウム、アンモニウム、脂肪族アンモニウム或いはそれらの混合イオンを示す。〕

[In the formula, M represents a coordination center metal, and examples thereof include Sc, Ti, V, Cr, Co, Ni, Mn, and Fe. Ar is an aryl group, which is an aryl group such as a phenyl group or a naphthyl group, and may have a substituent. In this case, examples of the substituent include a nitro group, a halogen group, a carboxyl group, an anilide group, an alkyl group having 1 to 18 carbon atoms, and an alkoxy group having 1 to 18 carbon atoms. X, X ′, Y and Y ′ are —O—, —CO—, —NH—, —NR— (R is an alkyl group having 1 to 4 carbon atoms). C ⁺ represents a counter ion and represents hydrogen, sodium, potassium, ammonium, aliphatic ammonium, or a mixed ion thereof. ]

  In particular, Fe or Cr is preferred as the central metal, halogen, alkyl group or anilide group is preferred as the substituent, and hydrogen, alkali metal, ammonium or aliphatic ammonium is preferred as the counter ion. A mixture of complex salts having different counter ions is also preferably used.

  The following compounds are used to control the toner to be positively charged.

  Nigrosine modified products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs such as phosphonium salts Onium salts and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, Ferrocyanide, etc.); metal salt of higher fatty acid; diorganotin oxide such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, di Black hexyl scan such diorgano tin borate such tin borate; guanidine compounds; imidazole compounds. These can be used alone or in combination of two or more. Among these, triphenylmethane compounds and quaternary ammonium salts whose counter ions are not halogen are preferably used. The following formula (II)

〔式中Ｒ₁はＨ又はＣＨ₃を示し、Ｒ₂及びＲ₃は置換または未置換のアルキル基（好ましくは、Ｃ１〜Ｃ４）を示す〕
で表されるモノマーの単重合体；前述したスチレン、アクリル酸エステル、メタクリル酸エステルの如き重合性モノマーとの共重合体を正荷電性制御剤として用いることができる。この場合、この単重合体及び共重合体は荷電制御剤としての機能と、結着樹脂（の全部または一部）としての機能を有する。

[Wherein R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably C1 to C4)]
A copolymer with a polymerizable monomer such as styrene, acrylic acid ester or methacrylic acid ester described above can be used as a positive charge control agent. In this case, the homopolymer and copolymer have a function as a charge control agent and a function as a binder resin (all or a part thereof).

  As specific examples of the charge control agent, those preferable for negative charge include, for example, Spiron Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44. , S-54, E-84, E-88, E-89 (Orient Chemical Co., Ltd.), and preferable examples for positive charging include TP-302, TP-415 (Hodogaya Chemical Co., Ltd.), Examples thereof include BONTRON (registered trademark) N-01, N-04, N-07, P-51 (Orient Chemical Co.), and Copy Blue PR (Clariant).

  As a method of incorporating a charge control agent into the toner, there are a method of adding it inside the toner particles and a method of adding it externally. The amount of these charge control agents used is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the binder resin.

  As a method for producing the toner of the present invention, the above-described toner constituent materials are sufficiently mixed by a ball mill or other mixer, and then kneaded well using a heat kneader such as a hot roll kneader or an extruder, and then solidified by cooling. Thereafter, a method of obtaining toner by mechanically pulverizing and classifying the pulverized powder is preferable. In addition, a polymerization method in which a predetermined material is mixed with a monomer that constitutes the binder resin to obtain an emulsion suspension, followed by polymerization to obtain a toner; a so-called microcapsule toner comprising a core material and a shell material In which a predetermined material is contained in the core material, the shell material, or both of them; and a method of obtaining the toner by dispersing the constituent materials in the binder resin solution and then spray-drying. Further, the toner of the present invention can be produced by sufficiently mixing the desired additive and toner particles with a mixer using the various methods described above as required.

  For example, as a mixer, Henschel mixer (Mitsui Mining Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocorn (Okawara Seisakusho Co., Ltd.); (Pacific Kiko Co., Ltd.); Ladige mixer (Matsubo Co., Ltd.), and KRC kneader (Kurimoto Iron Works Co.); Bus Co Kneader (Buss Co.); TEM type extruder (Manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.); Mining company); MS pressure kneader, Nider Ruder (Moriyama Seisakusho); Banbury mixer (Kobe Steel) As a pulverizer, a counter jet mill, a micron jet, an inomizer (manufactured by Hosokawa Micron); an IDS type mill, a PJM jet pulverizer (manufactured by Nippon Pneumatic Industry Co., Ltd.); a cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet O Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); , Micron Classifier, Spedick Classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo Classifier (Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Co.); Elbow Jet (Nittetsu Mining) ), Disper Separator (manufactured by Nippon Pneumatic Kogyo Co., Ltd.); YM Microcut (manufactured by Yaskawa Shoji Co., Ltd.), and as a sieving device used for sieving coarse particles etc. Gyroshifter (manufactured by Deoksugaku Kosakusha); Vibrasonic system (manufactured by Dalton); Soniclean (manufactured by Shinto Kogyo); Turbo screener (manufactured by Turbo Kogyo); Micro shifter (manufactured by Hadano Sangyo); Circular vibration A sieve etc. are mentioned.

  When a negatively chargeable toner is used as the toner according to the present invention, it is preferable that the toner carrier has at least a base and a negatively chargeable resin coating layer formed of a resin composition on the surface of the base. In this case, the metal compound fine particles also need to be negatively charged, but with this configuration, the metal compound fine particles can be prevented from taking an excessive negative charge amount, and toner carrier contamination can be easily suppressed.

  Here, the positive / negative judgment method of the chargeability of the resin coating layer will be described.

  First, a coating material in which a resin for coating the toner carrier for measuring the charging polarity is dispersed is applied on the SUS plate piece side by a # 60 bar coater, and this is heated and dried to form a film (the temperature and time for drying and heating are the same). A sample plate is prepared (until the solvent is completely evaporated in the case of a plastic resin, or until the resin is completely crosslinked in the case of a thermosetting resin). The sample plate is left overnight at 23 ° C. and 60% relative humidity with the SUS side grounded. Next, the sample plate is set in a surface charge measuring device TS-100AS (manufactured by Toshiba Chemical Co., Ltd.) shown in FIG. 3, and iron powder 32 having a particle size of 90 μm is placed in a dropping device 31 and placed on the sample plate 33 for 20 seconds. And is received by a pre-grounded receiver 34. The polarity at this time is read and set as the charging polarity of the resin coating layer with respect to the iron powder. EFV200 / 300 (manufactured by Nippon Iron Powder) is used as the iron powder.

As a preferable means for making the resin coating layer in the present invention have a negative chargeability, for example, in JP-A-10-3204040 and JP-A-11-052711, a conventional positive charge control agent for toner is known. A quaternary ammonium salt compound, that is, a quaternary ammonium salt compound that itself is positively charged with respect to iron powder and a binder resin for a resin coating layer, in particular, a part of the binder resin for a resin coating layer or When the resin coating layer of the developer carrier is formed by using all having at least one of —NH ₂ group, ═NH group and —NH— bond in the molecular structure, a quaternary ammonium salt A technique is disclosed in which a compound is incorporated into a binder resin for a resin coating layer, and the resin coating layer exhibits strong negative chargeability.

  As the quaternary ammonium salt compound suitably used in the present invention, those having positive chargeability with respect to iron powder are used. Examples thereof include compounds represented by the following general formula (1).

（式中のＲ¹、Ｒ²、Ｒ³、Ｒ⁴は、各々、置換基を有しても良いアルキル基、置換基を有しても良いアリール基、アルアルキル基を表し、Ｒ¹〜Ｒ⁴は各々同一でもあるいは異なっていてもよい。Ｘ^-は酸の陰イオンを表す。）

^{(R 1, R 2, R} 3 in the formula, R ⁴ are each an alkyl group which may have a substituent, an aryl group which may have a substituent group, an aralkyl group, R ¹ ~ R ⁴ may be the same or different, and X ⁻ represents an anion of an acid.)

  Specific examples of the quaternary ammonium salt compound that is suitably used in the present invention and is positively charged with respect to iron powder include those represented by the following formulas (3) to (10). Of course, the present invention is not limited to these examples.

  The addition amount of the quaternary ammonium salt compound used in the present invention as described above is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the binder resin for the resin coating layer. If the amount is less than 1 part by mass, the effect of optimizing the charge amount due to the addition is not observed. If the amount exceeds 100 parts by mass, the existing amount in the binder resin for the resin coating layer becomes excessive and the properties of the original resin are impaired. It tends to cause a decline.

The binder resin for the resin coating layer used in the resin coating layer of the toner carrier used in the present invention is not particularly limited, but a part or all of the resin coating layer binding resin is at least —NH in its molecular structure. It preferably has a structure of _two groups, ═NH group, or —NH— bond. By forming the resin coating layer using such a binder resin for the resin coating layer, the effect of the present invention is easily exhibited. In the present invention, if the resin coating layer having the above-described configuration is used as the resin coating layer of the toner carrier, the clear reason for the resin coating layer itself changing to a negative charge imparting property is not clear, but iron powder A quaternary ammonium salt compound that is positively charged with respect to the resin and a binder resin for a resin coating layer having at least one structure of -NH ₂ group, = NH group, or -NH- bond By forming the resin coating layer, the quaternary ammonium salt is taken into the structure of the binder resin for the resin coating layer. At that time, the original structure of the quaternary ammonium salt having a positive polarity is lost, and the chargeability of the binder resin for the resin coating layer incorporating these has a uniform negative chargeability. This is thought to contribute to the optimization of the charging of the fine particles.

Examples of the substance having —NH ₂ group include a primary amine represented by R—NH ₂ or a polyamine having them, a first amide represented by RCO—NH ₂ , or a polyamide having them. Examples of the substance having = NH group include a secondary amine represented by R = NH or a polyamine having them, a second amide represented by (RCO) ₂ = NH, or a polyamide having them. Examples of the substance having an —NH— bond include polyurethane having an —NHCOO— bond in addition to the above-described polyamine, polyamide and the like. As the binder resin for the coating layer, an industrially synthesized resin containing one or more of the above substances as a copolymer or a copolymer is suitably used. Of these, from the viewpoint of versatility, phenol resins, polyamide resins, urethane resins and the like produced by adding and condensing phenols and aldehydes using a nitrogen-containing compound as a catalyst can be preferably used.

As the binder resin for other resin coating layers, generally known resins can be used. For example, thermoplastic resins such as styrene resins, vinyl resins, polyethersulfone resins, polycarbonate resins, polyphenylene oxide resins, polyamide resins, fluororesins, fiber resins, acrylic resins, epoxy resins, polyester resins, alkyd resins Thermal or photo-curable resins such as phenol resin, melamine resin, polyurethane resin, urea resin, silicone resin, polyimide resin, etc. can be used. Among them, those having releasability such as silicone resin, fluorine resin, or polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, phenol resin, polyester resin, polyurethane resin, styrene resin, acrylic resin Those having excellent mechanical properties are more preferred. However, in order to easily achieve the configuration of the present invention, as described above, the binder resin for the coating layer having at least one structure of —NH ₂ group, ═NH group, or —NH— bond as described above. Is preferably used. Moreover, it is also possible to mix and use with the said general binder resin for coating layers.

  Further, as a preferred means for making the resin coating layer of the toner carrier according to the present invention negatively chargeable, a method of adding a benzylic acid compound as a substance for making the resin coating layer negatively chargeable.

  Examples of the benzylic acid compound used in the present invention include an aluminum compound of benzylic acid, a boron compound, a zinc compound, and a chromium compound. Examples of the benzylic acid compound include an aluminum compound of benzylic acid having an unsubstituted group or a substituent represented by the following general formula (11).

（式中、Ｒ⁵とＲ⁶は同一であっても異なっていても良く、各々、直鎖または分岐したアルキル基、アルケニル基、アルコキシル基、ハロゲン原子、ニトロ基、シアノ基、アミノ基、カルボキシル基及び水酸基からなる群から選ばれる置換基を示し、ｍ及びｎは０〜５の整数を示す。）

(In the formula, R ⁵ and R ⁶ may be the same or different, and each represents a linear or branched alkyl group, alkenyl group, alkoxyl group, halogen atom, nitro group, cyano group, amino group, carboxyl group. And represents a substituent selected from the group consisting of a group and a hydroxyl group, and m and n represent an integer of 0 to 5.)

  Among these, an aluminum compound of benzyl acid represented by the following general formula (12) is more preferable.

（式中、Ｒ⁵とＲ⁶は同一であっても異なっていても良く、各々、直鎖または分岐したアルキル基、アルケニル基、アルコキシル基、ハロゲン原子、ニトロ基、シアノ基、アミノ基、カルボキシル基及び水酸基からなる群から選ばれる置換基を示し、ｍ及びｎは０〜５の整数を示す。また、Ｙは１価のカチオン、水素、リチウム、ナトリウム、カリウム、アンモニウム及びアルキルアンモニウムを示す。）

(In the formula, R ⁵ and R ⁶ may be the same or different, and each represents a linear or branched alkyl group, alkenyl group, alkoxyl group, halogen atom, nitro group, cyano group, amino group, carboxyl group. A substituent selected from the group consisting of a group and a hydroxyl group, m and n are each an integer of 0 to 5. Y is a monovalent cation, hydrogen, lithium, sodium, potassium, ammonium or alkylammonium. )

  In the toner carrier used in the present invention, in order to adjust the volume resistance of the resin coating layer, conductive fine powder may be dispersed and contained in the binder resin for the coating layer. Such conductive fine powder preferably has a number average particle size of 20 μm or less, and more preferably 10 μm or less. In order to avoid unevenness formed on the surface of the binder resin for coating layer, it is more preferable to use conductive fine powder having a number average particle diameter of 1 μm or less. The material of the conductive fine powder may be the same as or different from the metal compound fine particles mixed in the toner.

  Here, the average particle diameter of the conductive fine powder is measured in substantially the same manner as in the case of the particle diameter of the metal compound fine particles. That is, a liquid module is attached to a laser diffraction type particle size distribution measuring device “LS-230 type” (manufactured by Coulter), a particle size of 0.04 to 2000 μm is set as a measurement range, and the D50 of particles is obtained by the volume-based particle size distribution obtained. Is calculated. However, as a dispersion solvent, a small amount of surfactant was added to 10 ml of pure water, 10 mg of a conductive fine powder was added thereto, and the mixture was dispersed for 10 minutes with an ultrasonic disperser (ultrasonic homogenizer). Measurement is performed with a measurement time of 90 seconds and a measurement count of 1.

  The conductive fine powder used in the present invention includes carbon black such as furnace black, lamp black, thermal black, acetylene black, channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide, potassium titanate, antimony oxide. And metal oxides such as indium oxide; metals such as aluminum, copper, silver and nickel; inorganic fillers such as graphite, metal fibers and carbon fibers.

  As the addition amount of the conductive fine powder in the resin coating layer described above, a preferable range is 100 parts by mass or less with respect to 100 parts by mass of the binder resin for the coating layer. A more preferable addition amount is 40 parts by mass. When the addition amount exceeds 100 parts by mass, the coating strength is liable to decrease, and when a large amount of non-chargeable particles are added, the charge amount of the toner can be decreased.

  As a constitution of the resin coating layer of the toner carrier used in the present invention, by further dispersing a lubricating substance in the resin coating layer, contamination of the toner carrier by the metal compound fine particles can be easily suppressed, and the effect of the present invention can be achieved. It is preferable because it is promoted. Examples of the lubricating substance include graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc, and fatty acid metal salts such as zinc stearate. Is preferably used because it does not impair the conductivity of the coating layer. These lubricating substances preferably have a number average particle diameter of preferably about 0.2 to 20 μm, more preferably 0.3 to 15 μm.

  In the present invention, the average particle size of the lubricating substance is 0. 0 mm when a liquid module is attached to a laser diffraction particle size distribution measuring device “LS-230 type” (manufactured by Coulter, Inc.) in the same manner as the particle size measurement of the conductive fine powder. The particle size of 04 to 2000 μm is taken as the measurement range, and the D50 of the particle is calculated from the obtained volume-based particle size distribution.

  As the addition amount of the lubricating substance, a particularly preferable result is given in the range of 10 to 120 parts by mass with respect to 100 parts by mass of the binder resin for the coating layer. When the addition amount exceeds 120 parts by mass, the strength of the coating layer tends to decrease, and when a large amount of non-chargeable additive is added, the charge amount of the toner decreases. Conversely, if the amount is less than 10 parts by mass, it is difficult to obtain the effect of adding metal compound fine particles to the toner carrier contamination.

  In addition to the additive substances described above, the resin coating layer of the toner carrier stabilizes the surface roughness by dispersing spherical particles in the resin coating layer, and the toner coating amount on the toner carrier is optimized. It is possible to The spherical particles maintain a uniform surface roughness on the surface of the coating layer of the toner carrier. At the same time, even when the surface of the coating layer is worn, there is little change in the surface roughness of the coating layer. Has the effect of making it difficult to generate.

  The spherical particles used in the present invention have a number average particle size of 0.3 to 30 μm, preferably 2 to 20 μm. If the number average particle size of the spherical particles is less than 0.3 μm, not only the effect of imparting uniform roughness to the surface and the effect of stabilizing the charging performance thereby will be insufficient, but also the adhesion of metal compound fine particles will be suppressed. Can be difficult. Further, the further lowering of the transportability due to the wear of the coating layer may cause the toner to be poorly charged by friction, and the toner carrier may be contaminated by the toner, which is not preferable because it may lead to ghost deterioration and image density reduction. When the number average particle diameter exceeds 30 μm, the surface roughness of the coating layer becomes too large, the amount of toner transport increases, and it becomes difficult for the toner layer regulating portion to be sufficiently regulated, and the toner is not charged. It becomes difficult to perform sufficiently, and problems such as deterioration in image quality and increase in reversal fog are likely to occur. Furthermore, it is not preferable because the mechanical strength of the coating layer decreases and the durability of the film decreases.

  The number average particle size of the spherical particles is also 0.04 to 0.04 when a liquid module is attached to a laser diffraction type particle size distribution measuring device “LS-230 type” (manufactured by Coulter) in the same manner as the particle size measurement of the conductive fine powder. The particle size of 2000 μm is taken as the measurement range, and the D50 of the particle is calculated from the obtained volume-based particle size distribution.

Spherical particles true density of 3 g / cm ³ or less, preferably 2.7 g / cm ³ or less, it is better and more preferably from 0.9~2.3g / cm ^3. That is, when the true density of the spherical particles exceeds ³ g / cm ³ , the dispersibility of the spherical particles in the coating layer becomes insufficient, so that it is difficult to impart uniform roughness to the coating layer surface. Also, since the storage stability of the paint is not good, it is difficult to obtain the surface of the triboelectric charge imparting member having uniform surface irregularities. Even when the true density of the spherical particles is less than 0.9 g / cm ³ , the dispersibility and storage stability of the spherical particles in the coating layer tend to be insufficient.

  The true density of the spherical particles was measured using a dry densitometer Accuvic 1330 (manufactured by Shimadzu Corporation).

  In the present invention, “spherical” in the spherical particles means that the ratio of the major axis / minor axis of the particles is about 1.0 to 1.5. In the present invention, the ratio of major axis / minor axis is preferably 1. It is preferable to use particles of 0 to 1.2. When the ratio of the major axis / minor axis of the spherical particles exceeds 1.5, the coating layer surface roughness becomes non-uniform, which leads to rapid and uniform frictional charging of the toner and the strength of the conductive coating layer. It is not preferable.

  As the spherical particles used in the present invention, known spherical particles can be used. Examples include spherical resin particles, spherical metal oxide particles, and spherical carbonized particles. Spherical resin particles are obtained, for example, by suspension polymerization, dispersion polymerization, and the like, and a suitable surface roughness can be obtained with a smaller addition amount, and a more uniform surface shape can be easily obtained. Examples of such spherical particles include acrylic resin particles such as polyacrylate and polymethacrylate, polyamide resin particles such as nylon, polyolefin resin particles such as polyethylene and polypropylene, silicone resin particles, phenol resin particles, and polyurethane resins. Examples thereof include resin particles, styrene resin particles, and benzoguanamine particles. The resin particles obtained by the pulverization method may be used after thermally or physically spheroidizing.

An inorganic fine powder may be attached to the surface of the spherical particles or may be fixed. Examples of such inorganic fine powder include oxides such as SiO ₂ , SrTiO ₃ , CeO ₂ , CrO, Ai ₂ O ₃ , ZnO and MgO, nitrides such as Si ₃ N ₄ , carbides such as SiC, CaSO ₄ , Examples thereof include sulfates such as BaSO ₄ and CaCO ₃ , and carbonates.

  The inorganic fine powder attached to the spherical particles may be used after being treated with a coupling agent. In particular, it is preferable to use spherical particles to which an inorganic fine powder treated with a coupling agent is attached for the purpose of improving the adhesion to the binder resin or imparting hydrophobicity to the particles. Examples of such a coupling agent include a silane coupling agent, a titanium coupling agent, and a zircoaluminate coupling agent. More specifically, silane coupling agents include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyl. Dimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyldi Ethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyl Rudisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethylpolysiloxane having 2 to 12 siloxane units per molecule, each containing a hydroxyl group bonded to one silicon atom at each terminal unit Examples thereof include siloxane.

  By attaching the inorganic fine powder treated with the coupling agent to the spherical particle surface in this way, dispersibility in the resin coating layer, uniformity of the resin coating layer surface, stain resistance of the resin coating layer, The charge imparting property to the toner, the abrasion resistance of the resin coating layer, and the like can be improved.

The spherical particles used in the present invention are more preferably conductive. That is, by imparting electrical conductivity to the spherical particles, charge is less likely to accumulate on the particle surface due to the electrical conductivity, reducing the contamination of the metal compound fine particles and improving the charge imparting property to the toner. In the present invention, the conductivity of the spherical particles is preferably 10 ⁹ Ωcm or less, more preferably 10 ⁻¹ to 10 ⁶ Ωcm.

In the present invention, when the volume resistance of the spherical particles exceeds 10 ⁹ Ωcm, the spherical particles exposed on the surface of the coating layer due to wear are likely to cause contamination and fusion of not only the metal compound fine particles but also the toner, and quickly. Moreover, it is difficult to perform uniform charging, which is not preferable.

  As a method for obtaining such conductive spherical particles, the following methods are preferable, but are not necessarily limited to these methods.

  As a method for obtaining particularly preferable conductive spherical particles used in the present invention, for example, low density and good conductive spherical particles obtained by carbonizing and / or graphitizing by firing resin spherical particles or mesocarbon microbeads. A method for obtaining carbon particles may be mentioned.

  Examples of the resin used for the resin spherical particles include phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile.

  In addition, mesocarbon microbeads can be usually produced by washing spherical crystals formed in the process of heating and firing the medium pitch with a large amount of a solvent such as tar, medium oil, and quinoline.

  More preferable methods for obtaining conductive spherical particles include a mechanochemical method on the surface of spherical resin particles such as phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile. And a method of obtaining conductive spherical carbon particles by coating the bulk mesophase pitch with, and heat-treating the coated particles in an oxidizing atmosphere, followed by firing in an inert atmosphere or vacuum to carbonize and / or graphitize. It is done. The spherical carbon particles obtained by this method are more preferable because the conductivity of the spherical carbon particles obtained by graphitization is improved since the coating of the spherical carbon particles is advanced.

The conductive spherical carbon particles obtained by the above method can control the conductivity of the spherical carbon particles obtained by changing the firing conditions in any method, and are preferably used in the present invention. In addition, in some cases, the spherical carbon particles obtained by the above-described method have a conductive metal and / or metal within a range in which the true density of the conductive spherical particles does not exceed ³ g / cm ³ in order to further increase the conductivity. Oxide plating may be applied.

  As another method for obtaining the conductive spherical particles used in the present invention, the conductive fine particles having a particle size smaller than the particle size of the core particles are mechanically mixed with the core particles made of the spherical resin particles at an appropriate blending ratio. When the conductive particles are uniformly adhered to the periphery of the core particle by the action of van der Waals force and electrostatic force, the core particle is caused by a local temperature rise caused by, for example, applying mechanical impact force. Examples thereof include a method of obtaining spherical resin particles obtained by softening the surface, forming conductive fine particles on the surface of the core particles, and conducting the conductive treatment.

  Another method for obtaining the conductive spherical particles used in the present invention is to obtain conductive spherical particles in which the conductive fine particles are dispersed by uniformly dispersing the conductive fine particles in the spherical resin particles. It is done. As a method for uniformly dispersing the conductive fine particles in the spherical resin particles, for example, the binder resin used for the spherical resin particles and the conductive fine particles are kneaded to disperse the conductive fine particles, and then cooled and solidified. A method of obtaining conductive spherical particles by pulverizing to a predetermined particle size and spheronizing by mechanical treatment and thermal treatment; or a polymerization initiator, conductive agent in a polymerizable monomer used for spherical resin particles; The finely divided fine particles and other additives are added, and the monomer composition uniformly dispersed by a disperser is suspended in an aqueous phase containing a dispersion stabilizer so as to have a predetermined particle diameter by a stirrer or the like. And a method of performing polymerization to obtain spherical particles in which conductive fine particles are dispersed.

  The conductive fine particles described above may be the same as or different from the above-described metal compound fine particles used by mixing with toner.

  Next, the configuration of the toner carrier used in the present invention will be described.

  The toner carrier comprises a substrate and a resin coating layer surrounding and covering the substrate. Examples of the shape of the substrate include a cylindrical member, a columnar member, and a belt-like member. In the developing method in which the latent image carrier is not contacted, a metal cylindrical member is preferably used, and specifically, a metal cylindrical tube is preferably used. As the metal cylindrical tube, nonmagnetic materials such as stainless steel, aluminum and alloys thereof are preferably used. In addition, as a substrate in the development method in which the latent image carrier is brought into direct contact, a cylindrical member having a layer structure including rubber or elastomer such as urethane, EPDM, or silicone is preferably used.

  Further, in the present invention, when magnetic toner is used, a magnet roller or the like in which a magnet is provided is disposed and used in the toner carrying body in order to magnetically attract and hold the toner on the toner carrying body. May be. In that case, the substrate may be cylindrical and a magnet roller may be disposed inside the substrate.

  The method for forming the resin coating layer of the present invention is not particularly limited, and can be performed by a normal method. For example, a coating liquid containing the binder resin for the coating layer and the quaternary ammonium salt compound is applied to the base material of the toner carrier by a method such as dipping, spraying, or brushing and dried. Then, the toner carrier used in the present invention can be obtained.

  Next, an aspect of the configuration of the image forming apparatus of the present invention will be described with reference to FIG. This image forming apparatus is a laser printer (recording apparatus) of a development simultaneous cleaning process (cleanerless system) using a transfer type electrophotographic process. It has a process cartridge from which a cleaning unit having a cleaning member such as a cleaning blade is removed, and a magnetic one-component toner is used as the toner. This image forming apparatus is an example of an image forming apparatus for non-contact development in which the toner layer on the toner carrier and the latent image carrier are arranged in non-contact, but the toner layer on the toner carrier and the latent image carrier An image forming apparatus in contact with the body may be used.

  Reference numeral 1 denotes a rotating drum type OPC photosensitive member as a latent image carrier, which is rotationally driven at a peripheral speed (process speed) of 120 mm / sec in the clockwise direction (direction of an arrow).

  Reference numeral 2 denotes a charging roller as a contact charging member. The charging roller 2 is disposed in pressure contact with the photoreceptor 1 with a predetermined pressing force against elasticity, and here, a direct injection charging mechanism is used. Reference numeral n denotes a charging contact portion that is a contact portion between the photosensitive member 1 and the charging roller 2. In this aspect, the charging roller 2 is rotationally driven at a peripheral speed of 120 mm / sec in the facing direction (opposite to the moving direction of the photosensitive member surface) at the contact portion n with the photosensitive member 1. That is, the surface of the charging roller 2 as a contact charging member has a relative speed difference of 200% relative to the surface of the photoreceptor 1.

The relative movement speed ratio indicating the relative speed difference described here can be expressed by the following equation.
Relative moving speed ratio (%) = | (Vc−Vp) / Vp | × 100
(Where Vc is the moving speed of the charging member surface, Vp is the moving speed of the latent image carrier surface, and Vc is the time when the charging member surface moves in the same direction as the latent image carrier surface at the contact portion. (The value has the same sign as Vp.)

  In the present invention, the ratio of the moving speed of the surface of the latent image carrier and the relative moving speed of the surface of the charging member facing it is preferably 10 to 500%, more preferably 20 to 400%. When the relative movement speed ratio is less than 10%, the contact probability between the contact charging member and the latent image carrier cannot be increased sufficiently, and the chargeability of the latent image carrier by direct injection charging is maintained. Difficult to do. Furthermore, charging of the latent image carrier is inhibited by limiting the total amount of the toner component interposed in the contact portion between the latent image carrier and the contact charging member by rubbing between the contact charging member and the latent image carrier. The effect of suppressing toner and the effect of improving the toner recovery in the simultaneous development cleaning by leveling the pattern of the residual transfer toner cannot be sufficiently obtained. When the relative moving speed ratio is larger than 500%, the moving speed of the charging member surface is remarkably increased. Therefore, the toner component carried to the contact portion between the latent image carrier and the contact charging member. As a result, the latent image carrier and the contact charging member are likely to be worn or scratches are likely to occur, resulting in a shorter life.

  Further, when the moving speed of the charging member is 0 (the charging member is stationary), the contact point of the charging member with the latent image carrier becomes a fixed point. The contact portion is liable to be worn or deteriorated, and the effect of suppressing the charging inhibition of the latent image carrier and the effect of leveling the pattern of the residual toner after transfer and improving the recoverability of toner in the simultaneous development cleaning are liable to be lowered.

  In addition, conductive fine particles are applied to the surface of the charging roller 2 so that the coating amount is uniform in one layer. The conductive fine particles may be the same as or different from the metal compound fine particles mixed in the toner.

  A DC voltage of −600 V to −700 V is applied as a charging bias to the cored bar 2a of the charging roller 2 from the charging bias application power source S1. In this embodiment, the surface of the photoreceptor 1 is uniformly charged by a direct injection charging method to a potential (−630 V) substantially equal to the voltage applied to the charging roller 2.

  Reference numeral 3 denotes a laser beam scanner (exposure device) including a laser diode and a polygon mirror. This laser beam scanner outputs laser light whose intensity is modulated in accordance with the time-series electric digital pixel signal of the target image information, and scans and exposes the uniformly charged surface of the photoreceptor 1 with the laser light. By this scanning exposure, an electrostatic latent image corresponding to target image information is formed on the rotary photoconductor 1.

  Reference numeral 4 denotes a developing device. The electrostatic latent image on the surface of the photoreceptor 1 is developed as a toner image by the developing device. The developing device 4 of this embodiment is a non-contact type reversal developing device using negatively chargeable magnetic one-component toner as toner. The toner 4d contains toner particles (t) and metal compound fine particles (m).

  Reference numeral 4a denotes a non-magnetic toner carrier having a diameter of 16 mm and including a magnet roll 4b as a toner carrying / conveying member. The toner carrier 4a is disposed to face the photosensitive member 1 with a separation distance of 320 μm, and the surface of the photosensitive member 1 is moved by a developing portion (developing region portion) a which is a portion facing the photosensitive member 1. The photosensitive drum 1 is rotated at a peripheral speed ratio of 110% of the peripheral speed of the photosensitive member 1 so that the direction of movement and the moving direction of the surface of the developing sleeve 4a are in the forward direction.

  A thin layer of toner 4d is coated on the toner carrier 4a by an elastic blade 4c. The toner 4d is given a charge while the layer thickness on the developing sleeve 4a is regulated by the elastic blade 4c.

  The toner 4d coated on the toner carrying member 4a is conveyed to the developing unit a which is a portion opposite to the photosensitive member 1 and the toner carrying member 4a as the toner carrying member 4a rotates.

A developing bias voltage is applied to the toner carrier 4a from a developing bias applying power source S2. In the case of a reversal development system using a negatively chargeable toner, a preferred development bias voltage is a DC voltage of −0.3 × 10 ⁶ to −20 × 10 ⁶ (V / m), a frequency of 500 to 5000 Hz, and a peak-to-peak voltage of 3 One-component jumping development is performed between the toner carrying member 4a and the photosensitive member 1 using a superposed rectangular AC voltage of × 10 ⁶ to 10 × 10 ⁶ (V / m).

  Reference numeral 5 denotes a medium-resistance transfer roller as a contact transfer means, which forms a transfer nip b by contacting the photosensitive member 1 with a linear pressure of 98 N per meter of contact length in the longitudinal direction. A transfer material P as a recording medium is fed to the transfer nip b from a paper feed unit (not shown) at a predetermined timing, and a predetermined transfer bias voltage is applied to the transfer roller 5 from a transfer bias application power source S3. As a result, the toner image on the photosensitive member 1 side is sequentially transferred onto the surface of the transfer material P fed to the transfer nip portion b.

In this embodiment, the transfer roller-5 having a resistance of 5 × 10 ⁸ Ωcm is used, and transfer is performed by applying a DC voltage of + 2000V. That is, the transfer material P introduced into the transfer nip portion b is nipped and conveyed by the transfer nip portion b, and the toner images formed and supported on the surface of the photosensitive member 1 on the surface side are successively subjected to electrostatic force and pressing force. Will be transcribed.

  Reference numeral 6 denotes a fixing device such as a heat fixing method. The transfer material P that has been fed to the transfer nip b and has received the transfer of the toner image on the photoconductor 1 side is separated from the surface of the photoconductor 1 and is introduced into the fixing device 6 where the toner image is fixed and the image is received. It is discharged out of the apparatus as a formed product (print, copy).

  The image forming apparatus of this embodiment has removed the cleaning unit, and the residual transfer toner (transfer residual toner) remaining on the surface of the photoreceptor 1 after the toner image transfer to the transfer material P is not removed by the cleaner. As the photosensitive member 1 rotates, it reaches the developing portion a via the charging contact portion n and is simultaneously cleaned (collected) by the developing device 4.

  In the image forming apparatus of this aspect, the three process devices of the photoconductor 1, the charging roller 2, and the developing device 4 are collectively configured as a process cartridge that is detachable from the image forming apparatus main body. The combination of process devices to be processed into a process cartridge is not limited to the above, and is arbitrary.

  An appropriate amount of the metal compound fine particles m mixed in the toner 4d of the developing device 4 is transferred to the photoconductor 1 side together with the toner particles t when the electrostatic latent image on the photoconductor 1 is developed by the developing device 4.

  The toner image on the photoreceptor 1, that is, the toner particle t, is attracted to the transfer material P, which is a recording medium, and actively transfers at the transfer portion b due to the influence of the transfer bias. However, since the metal compound fine particles m on the photoconductor 1 are conductive, they do not actively move to the transfer material P side, and remain substantially adhered and held on the photoconductor 1.

  Since the image forming apparatus of this aspect does not have a cleaning process, the transfer residual toner particles t and the metal compound fine particles m remaining on the surface of the photoreceptor 1 after the transfer are separated from the photoreceptor 1 as the photoreceptor 1 rotates. It is carried to a charging contact portion n that is a contact portion with the charging roller 2 that is a contact charging member, and adheres to or mixes with the charging roller 2. Therefore, direct injection charging of the photosensitive member 1 is performed in a state where the metal compound fine particles m are present in the charging contact portion n.

  Due to the presence of the metal compound fine particles m, even when the toner particles t adhere to or mix in the charging roller 2, it is possible to maintain the close contact property and contact resistance of the charging roller 2 to the photoreceptor 1. The direct charging of the photoreceptor 1 can be performed.

  That is, the charging roller 2 is in close contact with the photoconductor 1 through the metal compound fine particles m, and the metal compound fine particles m rub against the surface of the photoconductor 1 without gaps. As a result, in the charging of the photoreceptor 1 by the charging roller 2, stable and safe direct injection charging without using a discharge phenomenon is dominant, and high charging efficiency that cannot be obtained by conventional roller charging or the like is obtained. Therefore, a potential substantially equal to the voltage applied to the charging roller 2 can be applied to the photoreceptor 1. Further, the transfer residual toner t adhering to or mixed in the charging roller 2 is gradually discharged from the charging roller 2 onto the photosensitive member 1 and reaches the developing portion a as the surface of the photosensitive member 1 moves, and is simultaneously developed in the developing device 4. It is cleaned (collected).

  In the simultaneous cleaning for development, the toner remaining on the photosensitive member 1 after the transfer is developed at the time of development after the next image forming process (after development, again at the time of developing the electrostatic latent image through the charging process and the exposure process). The image is recovered by a fog removal bias (fogging removal potential difference Vback which is a potential difference between the DC voltage applied to the development device and the surface potential of the latent image carrier) of the developing device. In the case of reversal development as in the image forming apparatus of the present embodiment, this simultaneous development cleaning includes an electric field for recovering toner from the dark portion potential of the latent image carrier by the developing bias to the toner carrier, and from the toner carrier to the latent image carrier. This is done by the action of an electric field that causes the toner to adhere (develop) to the light portion potential.

  Further, when the image forming apparatus is operated, the metal compound fine particles m contained in the toner of the developing device 4 migrate to the surface of the photoreceptor 1 at the developing portion a, and the transfer portion b is moved along with the movement of the surface of the photoreceptor 1. Then, new metal compound fine particles m are continuously supplied to the charging portion n by being carried to the charging contact portion n, so that the metal compound fine particles m decrease in the charging portion n due to dropping or the like. Even if the metal compound fine particles m are deteriorated, the chargeability is prevented from being lowered and good chargeability is stably maintained.

  Thus, in an image forming apparatus using a contact charging method, a transfer method, or a toner recycling process, a uniform charging property can be provided with a low applied voltage by using the simple charging roller 2 as a contact charging member. Moreover, although the charging roller 2 is contaminated with the transfer residual toner, the ozone-less direct injection charging can be stably maintained over a long period of time, and uniform charging properties can be provided. Therefore, it is possible to obtain an image forming apparatus with a simple configuration and low cost, which is free from troubles caused by ozone products, troubles caused by defective charging, and the like.

  Further, due to the lubrication effect (friction reduction effect) of the metal compound fine particles m on the contact surface n between the charging roller 2 and the photoreceptor 1, a speed difference is easily and effectively provided between the charging roller 2 and the photoreceptor 1. It becomes possible. By this lubricating effect, friction between the charging roller 2 and the photosensitive drum 1 is reduced, driving torque is reduced, and scraping or scratches on the surface of the charging roller 2 or the photosensitive drum 1 can be prevented. Further, by providing this speed difference, the chance that the metal compound fine particles m come into contact with the photosensitive member 1 at the mutual contact surface portion (contact portion) n between the charging roller 2 and the photosensitive member 1 is remarkably increased, and high contactability is achieved. Can be obtained. Therefore, good direct injection charging can be obtained, and a good image can be stably obtained.

  In this embodiment, the charging roller 2 is driven to rotate, and the rotation direction of the charging roller 2 rotates in the direction opposite to the moving direction of the surface of the photosensitive member 1, so that the charging roller n is carried on the photosensitive member 1. The transfer residual toner is temporarily collected on the charging roller 2 to obtain an effect of leveling the amount of transfer residual toner present in the charging portion n. For this reason, the occurrence of charging failure due to uneven distribution of the transfer residual toner at the charging contact portion is prevented, and more stable charging property can be obtained.

  Further, by rotating the charging roller 2 in the reverse direction, the transfer residual toner on the photoconductor 1 is once separated from the photoconductor 1 and charged, so that direct injection charging can be performed predominantly. In addition, the effect of reducing the drop of the metal compound fine particles m from the charging roller 2 is obtained, and the charging property of the photoreceptor is not lowered due to the excessive drop of the metal compound fine particles m from the charge roller 2.

  Also, a mode (contact charging member cleaning) in which the transfer residual toner adhering to and mixed in the contact charging member, which is a charging inhibiting factor, is efficiently excluded from the contact charging member during non-image recording such as between papers. If the image forming method in which the contamination level of the contact charging member due to the residual toner on the contact charging member is kept low in the present invention is used in combination with the present invention, the charging property and image characteristics can be further improved over a long period of time. Can be maintained.

  That is, a contact charging member cleaning mode is provided to apply a DC + AC voltage to the contact charging member, and the contact charging member carries metal compound fine particles to efficiently discharge the transfer residual toner contaminating the contact charging member. Also, high charging performance can be maintained with respect to charging characteristics after image formation with a high image ratio.

  Conventionally, the contact charging member and the toner are firmly adhered. However, by attaching metal compound fine particles as charge promoting particles between them and applying an AC bias of 5 to 1000 Hz, the contact charging member and the toner are attached. The contact charging member can be quickly cleaned by reducing the adhesion force and generating an appropriate potential difference between the contact charging member and the latent image carrier. That is, the charging method by direct injection is a method in which a charging potential approximately equal to the applied voltage is obtained, and therefore, a potential difference is hardly generated between the contact charging member and the latent image carrier, and the metal compound fine particles according to the present invention are used. However, it is difficult to completely clean the members. Therefore, a frequency of 5 to 1000 Hz at which a difference in bias is likely to occur before and after the charging portion is a desirable condition for discharging the toner.

  At that time, metal compound fine particles having the same amount of triboelectric charge as the toner are also discharged to some extent. Therefore, even if the metal compound fine particles are excessively consumed from the toner carrier during continuous printing, the amount discharged from the contact charging member is collected and replenished on the toner carrier by the developing unit. The image characteristic improvement effect can be maintained.

  When the frequency is less than 5 Hz, potential unevenness is generated on the latent image carrier corresponding to the frequency, and image density unevenness is likely to occur correspondingly. On the other hand, if the frequency exceeds 1000 Hz, the movement of the toner cannot follow, the cleaning effect is reduced and the chargeability is liable to decrease, and the movement of the metal compound fine particles cannot be followed. As a result, fog and transferability tend to deteriorate.

  Here, when various physical properties of the metal compound fine particles contained in the toner are measured, the toner container 4 is removed after the printing of a large number of sheets under the above-described conditions without the cleaning mode in the cleanerless system. A cleaner not shown is attached, and then the printer is operated in the normal cleaning mode to collect the metal compound fine particles in the cleaner container, and the measurement is repeated until a sufficient amount is collected.

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

[Production Example 1 of Metal Compound Fine Particles]
A hydrochloric acid aqueous solution having a pH of about 1 in which tin chloride and antimony chloride are mixed and dissolved so that the molar ratio of tin and antimony is 100: 7 is brought to 80 ° C., and an aqueous sodium hydroxide solution is added thereto to form a coprecipitate. Then, filtration and washing were performed to obtain a slurry of conductive fine particles. The obtained slurry was dried and crushed, then calcined at 500 ° C. for 3 hours, and crushed again. The obtained metal compound fine particles are referred to as metal compound fine particles 1. The physical properties of the metal compound fine particles 1 are a specific surface area of 18 × 10 ⁵ cm ² / cm ³ , a volume resistance of 4 × 10 ¹ Ωcm, D ₅₀ = 1.8 μm, D ₉₀ = 3.4 μm, and D ₁₀ = 0.7 μm. The tin oxide content was 93% by mass.

[Production Example 2 of Metal Compound Fine Particles]
In a heating mixer, 100 parts of the above metal compound fine particles 1 were stirred and mixed at 80 ° C. while spraying a solution obtained by adding 2.5 parts of amino-modified silicone oil to 100 parts of ethanol. The temperature was raised to 130 ° C. and a heat treatment for 30 minutes was performed. After taking out, it cooled to room temperature, crushed, and obtained the metal compound fine particle 2 which gave the surface treatment. The physical properties of the obtained metal compound fine particles 2 are as follows: specific surface area 17 × 10 ⁵ cm ² / cm ³ , volume resistance 7 × 10 ¹ Ωcm, D ₅₀ = 1.8 μm, D ₉₀ = 3.6 μm, D ₁₀ = 0. The tin oxide content was 91% by mass.

[Toner Production Example 1]
Material composition / binder resin (styrene-acrylic resin (glass transition temperature by DSC measurement Tg = 58 ° C., acid value 23.0 mgKOH / g, MPC by GPC (number average molecular weight) 7000, Mw (weight average molecular weight) 400000, monomer) Ratio: 72.5 parts of styrene, 20 parts of n-butyl acrylate, 7 parts of mono-n-butyl malate, 0.5 part of divinylbenzene) Magnetic iron oxide (average particle size: 0.20 μm, BET specific surface area: 8 0.0 m ² / g, coercive force: 3.7 kA / m, saturation magnetization: 82.3 Am ² / kg, remanent magnetization: 4.0 Am ² / kg 95 parts polypropylene wax (melting point 143 ° C., penetration at 25 ° C. Degree 0.5 mm) 4 parts Charge control agent 2 parts (iron complex of azo compound (1), where X = X ′ = Y = Y ′ = O, Ar is a naphtho having an anilide group as a substituent Le group, C ⁺ denotes a mixture of hydrogen ions and ammonium ions, respectively)
The above compound was melt-kneaded with a biaxial extruder heated to 130 ° C., and the cooled kneaded product was ground by a hammer mill. The pulverization was performed by mechanical pulverization using a turbo mill (manufactured by Turbo Kogyo Co., Ltd.). The resulting finely pulverized product was subjected to strict classification and removal of ultrafine powder and coarse powder with a multi-division classifier (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect to obtain black powder 1. The resulting black powder 1 had a weight average diameter of 7.8 μm and a specific gravity of 1.7 g / cm ³ .

next,
-Black powder 1 100 parts-Hydrophobic silica with a primary particle size of 8 nm
(BET 100 m ² / g hydrophobized with dimethyl silicone oil and hexamethyldisilazane) 0.8 parts / metal compound fine particles 2 3.0 parts Henschel mixer FM10C / l (Mitsui Mining Co., Ltd.) The toner 1 was obtained by mixing for 150 seconds.

[Photoconductor Production Example 1]
A 30 mm × 260.5 mm aluminum cylinder was used as a support, and a methanol solution of polyamide resin was applied thereon by a dipping method to provide an undercoat layer having a thickness of 0.5 μm.

  4 parts of oxytitanium phthalocyanine pigment, 2 parts of polyvinyl butyral resin and 80 parts of cyclohexanone were dispersed in a sand mill apparatus for about 4 hours. This dispersion was applied onto the undercoat layer to form a 0.2 μm charge generation layer.

  Next, 10 parts of a triphenylamine compound and 10 parts of a polycarbonate resin were dissolved in 100 parts of monochlorobenzene. This solution was applied onto the charge generation layer and dried with hot air to form a charge transport layer having a thickness of 20 μm.

  Next, as a charge injection layer, 50 parts of antimony-doped tin oxide fine particles surface-treated with silicone oil were dispersed in 150 parts of ethanol, and further 20 parts of polytetrafluoroethylene fine particles were added and dispersed. Thereafter, 150 parts of a resole thermosetting phenol resin was dissolved as a resin component to prepare a preparation solution.

  Using this prepared solution, a film was formed on the previous charge transport layer by a dip coating method, followed by drying with hot air to form a charge injection layer, whereby a photoreceptor 1 was obtained. At this time, the film thickness of the charge injection layer of the photoreceptor 1 is measured using an instantaneous multi-photometry system MCPD-2000 (manufactured by Otsuka Electronics Co., Ltd.) due to light interference because of the thin film, and the film thickness is 2 μm. there were. As another method for measuring the film thickness, the cross section of the film of the photoreceptor can be directly observed and measured with an SEM or the like.

[Production Example 1 of Charging Member]
A SUS roller having a diameter of 6 mm and a length of 264 mm is used as a core, and a medium-resistance foamed urethane layer is formed on the core as a roller. The medium resistance foam urethane layer is formulated with urethane resin, carbon black as a conductive material, sulfiding agent, foaming agent, etc. Further, the charging member 1 having a diameter of 12 mm and a length of 234 mm was prepared as a flexible member by cutting and polishing to adjust the shape and surface properties.

The obtained charging member 1 had a resistance value of 10 ⁵ Ωcm and a hardness of 26 degrees in Asker C hardness.

[Production Example 1 of toner carrier]
The production of the toner carrier will be described.

The following materials were dispersed with zirconia particles having a diameter of 2 mm using a sand mill for 3 hours, after which the zirconia particles were separated by sieving, and the solid content was adjusted to 33% with isopropanol to obtain paint 1.
-Carbon 20 parts-Graphite 80 parts-Phenol resin intermediate produced using ammonia as a catalyst (solid content 50%) 600 parts-Quaternary ammonium salt compound (1) represented by the above formula 3 10 parts-Number average particle Spherical carbon particles with a diameter of 5.2 μm (A) 30 parts / isopropanol 130 parts

The triboelectric charge amount of the quaternary ammonium salt compound with the iron powder was positive, as determined by the blow-off method using a commercially available triboelectric charge measuring device (TB-200 type manufactured by Toshiba Chemical). Further, spherical carbon particles A were used as the spherical particles. Table 3 shows the physical properties. The number average particle size was 5.2 μm, the true density was 1.51 g / cm ³ , the volume resistance was 7.5 × 10 ⁻² Ωcm, and the major axis / minor axis ratio was 1.15.

  The coating material 1 is formed by spraying a resin coating layer of about 10 μm on an Al cylinder having a diameter of 20 mm, then heated and cured by a hot air dryer at 150 ° C. for 30 minutes, and a toner carrier 1 having an Ra of about 1.3 μm. Was made.

<Example 1>
FIG. 1 shows an overall schematic configuration of the image forming apparatus of this example. FIG. 1 shows a laser printer (recording apparatus) of a development simultaneous cleaning process (cleanerless system) using a transfer type electrophotographic process. A process cartridge having a cleaning unit having a cleaning member such as a cleaning blade is removed, and a negatively chargeable magnetic one-component toner 1 is used as the toner. In this example, a non-contact development method is used in which the toner layer on the toner carrier and the latent image carrier are arranged in non-contact, but a contact development method can also be suitably used.

  The photosensitive member 1 serving as a latent image carrier is a rotary drum type OPC photosensitive member, and is driven to rotate at a peripheral speed (process speed) of 94 mm / sec in the X direction of an arrow.

As the contact charging member, the charging member 1 obtained in the charging member manufacturing example 1 is used as the charging roller 2. As shown in the figure, the charging roller 2 has a predetermined resistance against the photoreceptor 1 against elasticity. It is disposed in pressure contact with the pressing force. Reference numeral n denotes a charging contact portion which is a contact portion between the photosensitive member 1 and the charging roller 2. In this example, the charging roller 2 is rotationally driven at a peripheral speed of 100% in the facing direction (arrow Y direction) at the charging contact portion n that is a contact surface with the photoreceptor 1. That is, the surface of the charging roller 2 has a relative speed difference of 200% relative to the surface of the photoreceptor 1. Further, the metal compound fine particles 1 are applied to the surface of the charging roller 2 so that the application amount is uniform at approximately 1 × 10 ⁴ particles / mm ² .

  Further, a DC voltage of −650 V is applied as a charging bias to the cored bar 2a of the charging roller 2 from the charging bias application power source S1. In this example, the surface of the photoreceptor 1 is uniformly charged by a direct injection charging method to a potential (−630 V) substantially equal to the voltage applied to the charging roller 2.

  A laser beam scanner (exposure device) 3 including a laser diode, a polygon mirror, or the like, which is an exposure means, outputs laser light whose intensity is modulated in accordance with a time-series electric digital pixel signal of target image information. Then, the uniformly charged surface of the photoreceptor 1 is scanned and exposed. By this scanning exposure, an electrostatic latent image corresponding to target image information is formed on the surface of the rotating photosensitive member 1. The electrostatic latent image on the surface of the photoreceptor 1 is developed as a toner image by the developing device 4 as a developing unit.

  The developing device 4 of this example is a non-contact type reversal developing device using the toner 1 as the toner.

  As the toner carrier 4a, the toner carrier 1 described above is used, and a magnet roll having a development magnetic pole of 90 mT (900 gauss) is included, and the toner layer thickness regulating member is made of urethane having a thickness of 1.0 mm and a free length of 1.5 mm. The elastic blade 4c was brought into contact with a linear pressure of 29.4 N / m (30 g / cm). The gap between the photoreceptor 1 and the toner carrier 4a was 290 μm.

  In addition, the toner carrier 4a has a peripheral speed of 120 in the rotation direction and the forward direction (in the direction of arrow W) of the photosensitive member 1 at a developing portion a (developing region) that is a portion facing the photosensitive member 1. Rotate at a peripheral speed of%.

The toner carrier 4a is coated with a thin layer of toner 1 by an elastic blade 24c. The layer thickness of the toner with respect to the toner carrier 4a is regulated by the elastic blade 4c, and an electric charge is applied. At this time, the amount of toner coated on the toner carrier 4a was 11 g / m ² .

The toner coated on the toner carrying member 4a is conveyed to the developing unit a which is a facing portion between the photosensitive member 1 and the toner carrying member 4a by the rotation of the toner carrying member 4a. A developing bias voltage is applied to the toner carrier 4a from a developing bias applying power source S2. The developing bias voltage is a superposition of a DC voltage of −440 V and a rectangular AC voltage having a frequency of 1600 Hz and a peak-to-peak voltage of 1500 V (electric field strength of 5 × 10 ⁶ V / m). In the meantime, one-component jumping development was performed in the developing section a.

  A transfer roller 5 having a medium resistance as a contact transfer unit is brought into contact with the photosensitive member 1 with a linear pressure of about 98 N / m (100 g / cm) to form a transfer contact portion b. The transfer contact portion b is fed with a transfer material P at a predetermined timing from a paper supply unit (not shown), and a predetermined transfer bias voltage is applied to the transfer roller 5 from a transfer bias application power source S3. The toner image on the body 1 side is sequentially transferred onto the surface of the transfer material P fed to the transfer contact portion b.

In this example, the transfer roller 5 has a volume resistance value of 5 × 10 ⁸ Ωcm, and transfer was performed by applying a DC voltage of + 2000V. That is, the transfer material P introduced into the transfer contact portion b is nipped and conveyed by the transfer contact portion b, and the toner image formed and supported on the surface of the photosensitive member 1 on the surface side is successively subjected to electrostatic force. It is transferred by pressing force. The transfer material P that has been fed to the transfer contact portion b and has received the transfer of the toner image on the photosensitive member 1 side is separated from the surface of the photosensitive member, and is introduced into a fixing device 6 such as a heat fixing method as a fixing means. The toner image is fixed and discharged as an image formed product (print, copy) to the outside of the apparatus.

  In the image forming apparatus of this example, the cleaning means is removed, and residual toner remaining on the surface of the photoconductor 1 after the transfer of the toner image onto the transfer material P is not removed by the cleaner, and the photoconductor 1 rotates. At the same time, it reaches the developing portion a via the charging contact portion n and is simultaneously cleaned (collected) by the developing device 4.

  Conventionally, since the toner is an insulator, the mixing of the untransferred toner into the charging contact portion n is a factor that causes a charging failure in charging the photosensitive member. However, in the present invention, the metal compound fine particles 1, which are image quality improvers whose specific surface area is strictly controlled, are present in the charging contact portion n between the photosensitive member 1 and the charging roller 2, whereby the photosensitive member 1 of the charging roller 2. Because it can maintain close contact and resistance to the toner, ozone-less direct charging can be stably maintained over a long period of time at a low applied voltage regardless of contamination of the transfer roller 2 with the transfer residual toner, and uniform charging Can give sex.

[Evaluation]
The transfer efficiency is determined by tapering the transfer residual toner on the photoconductor after the solid black image transfer with a Mylar tape and pasting it on the paper. The Macbeth density value is C, and the Mylar is applied on the paper with the toner after the fixing before the transfer. When the Macbeth concentration of the tape was affixed to D and the Macbeth concentration of the Mylar tape affixed on unused paper was assumed to be E, it was approximately calculated by the following formula. If the transfer efficiency is 70% or more, there is practically no problem with durability.
Transfer efficiency (%) = (DC / DE) × 100

The resolving power in the initial stage of durability was evaluated by the reproducibility of a small-diameter isolated 1 dot at 600 dpi, which is easy to close due to the electrostatic latent image electric field and difficult to reproduce.
◎: Very good, 5 or less defects in 100 ○: Good, 6 to 10 defects in 100 Δ: Practical, 11 to 20 defects in 100 ×: Impractical, 100 More than 20 defects

The fog on the paper was measured using a REFECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku. A green filter was used as the filter. The fog value was calculated from the following formula using a solid white image. If the fog on paper is 2.0% or less, a good image is obtained.
Fog (reflectance) (%) = reflectance on standard paper (%)-reflectance of sample non-image area (%)

  The image density was measured with a Macbeth densitometer RD918 (manufactured by Macbeth). If it is 1.35 or more, it can be said that it is a practically sufficient numerical value. The triboelectric charge amount that the toner is charged with by the initial image quality evaluation and the friction with the toner carrier is the numerical value of the 20th printed image.

  In this embodiment, first, 20 g of the metal compound fine particles 2 are filled in the image forming apparatus, the apparatus is set on the printer body, and the metal compound fine particles 2 are applied onto the toner carrier 1. The amount of triboelectric charge that the metal compound fine particles 2 have due to friction with the carrier 1 was measured. As a result, a value of -1.2 mC / kg was obtained.

Next, after cleaning the image forming apparatus, 110 g of toner 1 is filled, and “the standby state for one hour after five continuous printing of image patterns consisting of only horizontal lines with a printing area ratio of 3%” is repeated. 500 sheets were printed and a durability evaluation test was conducted. As the transfer material, 75 g / m ² of A4 copy paper was used, and the evaluation was performed in an environment of an air temperature of 15 ° C. and a humidity of 10%.

  As a result, no deterioration in developability was observed up to the 500th sheet, and a good image without fogging was obtained. The results obtained are shown in Table 5.

[Production Example 3 of Metal Compound Fine Particles]
In a heating type mixer, 100 parts of the metal compound production example 1 was stirred and mixed at 80 ° C. while spraying a solution obtained by adding 2.5 parts of dimethyl silicone oil to 100 parts of ethanol. The temperature was raised to 180 ° C. and a heat treatment for 30 minutes was performed. After taking out, it cooled to room temperature, crushed, and obtained the metal compound fine particle 3 which surface-treated. The physical properties of the obtained metal compound fine particles 3 are as follows: specific surface area 18 × 10 ⁵ cm ² / cm ³ , volume resistance 1.2 × 10 ² Ωcm, D ₅₀ = 1.8 μm, D ₉₀ = 3.5 μm, D ₁₀ = The thickness was 0.7 μm, and the tin oxide content was 91% by mass.

[Toner Production Example 2]
-100 parts of the black powder 1-0.8 parts of the hydrophobic silica used in the toner production example 1-3.0 parts of the metal compound fine particles 3 The above materials are used in a Henschel mixer FM10C / l (manufactured by Mitsui Mining Co., Ltd.). A mixing process was performed for 150 seconds to obtain toner 2.

<Example 2>
The same evaluation as in Example 1 was performed by using toner 2 instead of toner 1.

  First, when the triboelectric charge amount of the metal compound fine particles 3 due to friction with the toner carrier 1 was measured, a value of −18.6 mC / kg was obtained. Next, 110 g of toner 2 is charged, and 500 sheets are printed in a mode in which “the image pattern consisting of only a horizontal line with a printing area ratio of 3% is printed continuously for 5 hours and then waits for one hour” as in the first embodiment. A print durability evaluation test was conducted.

  As a result, no deterioration in developability was observed up to the 500th sheet, and a good image without fogging was obtained. The results obtained are shown in Table 5.

[Production Example 2 of toner carrier]
A toner carrier 2 having an Ra of about 1.3 μm was prepared in the same manner as the toner carrier 1 except that the amount of the quaternary ammonium salt compound (1) represented by Formula 3 was 40 parts.

<Example 3>
The same evaluation as in Example 1 was performed using the toner carrier 2 instead of the toner carrier 1.

  When the triboelectric charge on which the metal compound fine particles 2 are borne by friction with the toner carrier 2 was measured, a value of -6.2 mC / kg was obtained. Further, in the durability evaluation test, good images without developing deterioration and fogging were obtained up to the 500th sheet.

[Toner Production Example 3]
-100 parts of the black powder 1-0.8 parts of the hydrophobic silica used in the toner production example 1-3.0 parts of the metal compound fine particles 1 The above materials are put into a Henschel mixer FM10C / l (manufactured by Mitsui Mining Co., Ltd.). For 150 seconds to obtain toner 3.

<Comparative Example 1>
The same evaluation as in Example 1 was performed using toner 3 instead of toner 1.

  When the triboelectric charge amount of the metal compound fine particles 1 due to friction with the toner carrier 1 was measured, a value of +1.1 mC / kg was obtained.

  Next, 110 g of toner 3 was filled, and a durability evaluation test was performed in the same mode as in Example 1.

  As a result, the decrease in image density and the deterioration of fog were noticeable, and the durability evaluation test was stopped at 80 sheets. The results obtained are shown in Table 5.

<Comparative example 2>
The same evaluation as in Example 2 was performed using the toner carrier 2 instead of the toner carrier 1.

  The triboelectric charge on which the metal compound fine particles 3 are borne by friction with the toner carrier 2 was -24.2 mC / kg. Next, when a durability evaluation test was performed, the deterioration of fog and the decrease in image density were remarkable.

[Production Example 3 of toner carrier]
A toner carrier 3 having a Ra of about 1.3 μm was prepared in the same manner as the toner carrier 1 except that the quaternary ammonium salt compound was not used.

<Comparative Example 3>
The same evaluation as in Example 1 was performed by using the toner carrier 3 instead of the toner carrier 1.

  The triboelectric charge amount of the metal compound fine particles 2 due to the friction with the toner carrier 3 was +1.3 mC / kg.

  Next, when a durability evaluation test was performed, a decrease in image density and a deterioration in fog were observed. Therefore, the durability evaluation test was stopped with 100 sheets. The results obtained are shown in Table 5.

<Comparative example 4>
Evaluation similar to Comparative Example 2 was performed using toner 2 instead of toner 1.

  The amount of triboelectric charge that the metal compound fine particles 3 were charged by friction with the toner carrier 3 was 0 mC / kg. In the durability evaluation test, a decrease in image density and deterioration of fog were observed, and the durability evaluation test was stopped with 120 sheets. The results obtained are shown in Table 5.

[Production Examples 4 to 18 of metal compound fine particles]
In production example 1 of metal compound fine particles, the metal compound fine particles were produced by appropriately adjusting the tin chloride concentration, the molar ratio of tin and antimony, the addition rate of the aqueous sodium hydroxide solution, the firing temperature and the firing time. The same surface treatment as in Production Example 2 was performed to obtain metal compound fine particles 4-18. Table 1 shows the physical properties of the obtained fine particles.

[Production Example 19 of Metal Compound Fine Particles]
An alkaline sodium stannate aqueous solution was controlled at 60 to 80 ° C., and an aqueous sulfuric acid solution was added thereto so that the pH did not fall below 7. A precipitate was formed, and filtered and washed to obtain a slurry of conductive fine particles. . The obtained slurry was dried and crushed, then calcined at 400 ° C. for 2 hours in a nitrogen atmosphere, and further at about 500 ° C. for 1 hour in a nitrogen / hydrogen mixed gas atmosphere. The same surface treatment as in Production Example 2 was performed to obtain metal compound fine particles 19. The physical properties of the obtained metal compound fine particles 19 are as follows: specific surface area 32 × 10 ⁵ cm ² / cm ³ , volume resistance 1 × 10 ³ Ωcm, D ₅₀ = 1.2 μm, D ₉₀ = 2.5 μm, D ₁₀ = 0. The thickness was 6 μm, and the tin oxide content was 98% by mass.

[Production Example 20 of metal compound fine particles]
An aqueous ammonium carbonate solution and an aqueous aluminum sulfate solution were mixed, put into an aqueous solution in which zinc oxide was dispersed, stirred at 60 ° C. for 1 hour, filtered and washed with water to obtain a slurry. This slurry was dispersed in ion-exchanged water, and carbon dioxide gas was blown in for 4 hours while maintaining the temperature at 30 ° C. After standing for a while, the supernatant was discarded, and the remaining slurry was spray-dried with a spray dryer to obtain a dry powder. This powder was thermally decomposed at 250 ° C. for 5 hours and then subjected to the same surface treatment as in Production Example 2 to obtain metal compound fine particles 20 composed of conductive zinc oxide fine particles.

[Toner Production Examples 4 to 20]
Using metal compound fine particles 4 to 20 as metal compound fine particles, toners 4 to 20 were obtained in the same manner as in toner production example 1.

[Toner Production Example 21]
In place of hydrophobic silica, 1.0 part of anatase-type titanium oxide having an average particle diameter of 50 nm, which was surface-treated with 15 parts of n-butyltrimethoxysilane (relative to titanium oxide), and toner production example 1 A toner 21 was obtained in the same manner.

[Toner Production Example 22]
In place of hydrophobic silica, 0.8 part of alumina having an average particle diameter of 7 nm, which was surface-treated with 20 parts of n-butyltrimethoxysilane (relative to alumina), was used in the same manner as in toner production example 1. Thus, toner 22 was obtained.

[Toner Production Example 23]
In place of the hydrophobic silica of Toner Production Example 1, 1.2 parts of hydrophobic silica having an average particle diameter of 90 nm that has been surface treated with 5 parts of hexamethyldisilazane (relative to silica) are used. Toner 23 was obtained in the same manner as in Example 1.

[Toner Production Example 24]
In Toner Production Example 1, the amount of metal compound fine particles 2 used was 3.5 parts, and toner 24 was obtained.

[Toner Production Example 25]
In Toner Production Example 1, the amount of metal compound fine particles 2 used was 0.3 parts, and toner 25 was obtained.

<Examples 4 to 22>
The same evaluation as in Example 1 was performed using toners 4 to 14, 17 to 19, and 21 to 25 instead of the toner 1. The results are shown in Table 5.

<Comparative Examples 5-7>
The same evaluation as in Example 1 was performed by using toners 15, 16, and 20 instead of toner 1. The results are shown in Table 5.

From the results of Examples 1 to 3 and Comparative Examples 1 to 7 in Table 5,
1) In frictional charging with the toner carrying member, if the charging polarity of the metal compound fine particles is not the same as the charging polarity of the toner, there is a problem in durability.
2) In frictional charging with the toner carrier, if the absolute value of the charge amount of the metal compound fine particles is less than 0.5 or more than 20, fogging deteriorates with durability.
I understand.

  It can also be seen that in the case of a negatively chargeable toner, it is possible to match the triboelectric charge polarity of the toner by subjecting the metal compound fine particles containing tin oxide to a surface treatment with a silicon compound.

From the results of Examples 1, 2, 4, 5, 12, and 13, it is possible to maintain good image characteristics and durability when the specific surface area of the metal compound fine particles used is 5 × 10 ⁵ cm ² / cm ³ or more. I understand. It can also be seen that it is preferably 10 × 10 ⁵ or more, more preferably 12 × 10 ⁵ or more. On the other hand, from the results of Examples 1, 6, 7, and 11, as the specific surface area of the metal compound fine particles used increases, the adhesion to the toner and the toner carrier increases, so the initial image density or the image density in the durability test is higher. It can also be seen that the lowering rate is preferably 80 × 10 ⁵ cm ² / cm ³ or less, more preferably 40 × 10 ⁵ or less. Furthermore, from the results of Example 16, it can be seen that the fog is slightly worsened under the condition that the metal compound fine particles contained in the toner have a surface area of 100 × 10 ⁵ / D ₅₀ <unit volume.

From the results of Examples 1, 4, 6, 8, 9, 10, 11, and 14, when D ₅₀ is small, there is a tendency that the image density tends to be low, and D ₅₀ is appropriately 0.4 μm or more, preferably 0. .5 μm or more. In addition, there is no problem greater than 0.5μm for D _90. D ₁₀ is more preferably as long as 0.3μm or more, it can be seen than 0.4μm is more preferable ranges. On the other hand, when D ₅₀ is large, fog tends to be deteriorated and the resolving power tends to be lowered. D ₅₀ is suitably 4.0 μm or less, preferably 3.5 μm or less. There is no problem if D ₁₀ is less than 3.5 μm. D ₉₀ is preferably 6.0 μm or less, and if it is 4.0 μm or less, it is understood that it is a more preferable range.

From the results of Example 15, it can be seen that the frictional charging property under low humidity is concerned when the resistance is high, but 1 × 10 ⁹ or less is sufficient.

  From the results of Examples 1 and 18 to 20, it can be seen that it is not preferable to use an inorganic fine powder having an average primary particle size of 90 nm or more as a fluidizing agent.

  It can also be seen from the results of Examples 1, 2, and 22 that there is no problem in image characteristics if the condition of 0.5 ≦ X × Y ≦ 6 is satisfied.

  Further, from the results of Examples 1, 4, 6, and 7, it can be seen that the fog is further improved if 0.05 ≦ | A / B | ≦ 2.00.

  Furthermore, in the results of Example 17, when reduction-treated tin oxide is used, not only the durability but also the image quality is improved.

[Production Examples 4 to 12 of toner carrier]
Toner carriers 4 to 12 were prepared according to the formulations shown in Tables 3 and 4.

<Examples 23 to 30, Comparative Example 8>
The same evaluation as in Example 1 was performed using toner carriers 4 to 12 instead of toner carrier 1.
The results are shown in Table 6.

In Table 6, from the results of Example 1 (above), Examples 23-30, Comparative Example 3 (above), Comparative Example 4 (above), and Comparative Example 8, the resin coating layer on the substrate of the toner carrier is 1) Having lubricating particles such as graphite 2) Containing a substance that imparts negative chargeability such as a quaternary ammonium salt compound or a benzylic acid compound 3) —NH ₂ group in the molecular structure = 4) containing conductive spherical particles having a number average diameter of 0.3 to 30 μm and a true density of 3 g / cm ³ or less for forming irregularities; It turns out that it is preferable to contain such an electroconductive substance.

[Toner Production Examples 26 to 29]
In the same manner as in Toner Production Example 1, black powders having an average particle diameter of 2.8 μm, 3.0 μm, 12.0 μm, and 12.5 μm were produced. For each of the obtained black powders, 3.0 parts by mass of the metal compound fine particles 2 and the hydrophobic silica used in Toner Production Example 1 were added to the toner of 2.8 μm and 3.0 μm. Toners 26 to 29 were produced by mixing 0.6 part of 0 part, 12.0 μm and 12.5 μm toner. Table 7 shows the physical properties of the obtained toner.

<Examples 31 and 32>
Evaluation was performed under the same conditions as in Example 1 except that toners 27 and 28 were used as toners. The results are shown in Table 8.

<Comparative Examples 9 and 10>
Evaluation was performed under the same conditions as in Example 1 except that toners 26 and 29 were used as toners. The results are shown in Table 8.

  From the results of Examples 31 and 32 and Comparative Examples 9 and 10, when the mass average particle diameter of the toner is 3 μm or more and 12 μm or less, high resolution can be obtained without lowering transferability and fogging. It is understood that is possible.

<Examples 33 to 37>
In the experimental conditions of the present embodiment, the charging roller application power source switch is switched by the sequence control circuit and the AC voltage is connected in series with the DC voltage when the printer is not recording images. DC voltage: -650V to the second cored bar 2a
AC voltage: peak-to-peak voltage 200V, frequency 3Hz, 5Hz, 500Hz, 1000Hz, 1010Hz
A rectangular wave superposition voltage was applied.

In addition, during the interval between the sheets, the developing sleeve 4a of the developing device 4 is similar to that at the time of image recording.
DC voltage: -440V
AC voltage: A peak-to-peak voltage of 1500 V, a frequency of 1600 Hz, and a rectangular wave superimposed voltage were applied.

  By maintaining these bias relationships, the toner that is negatively frictionally charged on the charging roller 2 is developed on the photosensitive member 1 (the toner on the charging roller 2 is discharged to the photosensitive member 1), and the toner is further developed. Can be recovered by the back contrast of the developing device 4.

  At the time of image recording by the printer, the same conditions as in Example 1 were used, and initial image characteristic evaluation was performed using toner 1 under the same conditions as in Example 1. The results are shown in Table 8.

  It can be seen that by applying the above process conditions to the toner and the image forming method according to the present invention, the balance between the initial image density and fog is improved.

  In addition, when the frequency of the superimposed AC voltage applied to the charging member is low, density unevenness (a phenomenon in which light and shade portions occur alternately) is seen in synchronization with the frequency, while when the frequency is high, fog and transferability tend to be slightly deteriorated. However, it can also be seen that the frequency is in the range of 5 to 1000 Hz.

1 is a schematic view of an example of an image forming apparatus used in the present invention. It is a suction type Faraday gauge used when judging the polarity of the external additive particles of the present invention. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus using an image forming method of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 2a Charging roller core 2b Flexible layer 3 Exposure device 4 Developing device 4a Developing sleeve 4b Magnet roll 4c Elastic blade 4d Toner 5 Transfer roller 6 Fixing device S1 Power supply for charging member S2 Power source for development S3 Transfer Power supply

Claims (33)

A charging step for charging the latent image carrier, a latent image forming step for writing image information as an electrostatic latent image on the charging surface of the latent image carrier charged in the charging step, and the electrostatic latent image for the toner When developing and visualizing using a developing device provided with a toner carrier that conveys toner to a development region facing the latent image carrier, the toner carrier comprises at least a substrate and a surface of the substrate. And a developing step having a resin coating layer formed of a resin composition, and a toner used in an image forming method for forming an image by repeating these steps,
The toner has at least toner particles and conductive metal compound fine particles and inorganic fine powder on the surface of the toner particles,
The toner particles are formed of at least a binder resin and a colorant,
The toner has a weight average particle diameter of 3 μm or more and 12 μm or less;
In frictional charging between the metal compound fine particles and the toner carrier, the metal compound fine particles exhibit the same charging polarity as the toner, and the absolute value of the triboelectric charge amount is 0.5 (mC / kg) or more and 20 (mC / kg). One-component developing toner characterized by the following. The specific surface area (cm ² / cm ³ ) of the metal compound fine particles is 5 × 10 ⁵ or more and 100 × 10 ⁵ or less, and the volume-based median diameter (D ₅₀ ; unit μm) is 0.4 μm or more and 4.0 μm or less. 2. The one-component developing toner according to claim 1, wherein D ₉₀ is greater than 0.5 μm and not greater than 6.0 μm.   3. The one-component developing toner according to claim 1, wherein the metal compound fine particles are non-magnetic. 4. The toner for one-component development according to claim 1, wherein the volume resistance of the metal compound fine particles is 1 × 10 ⁻¹ to 1 × 10 ⁹ Ωcm. The specific surface area (cm ² / cm ³ ) and volume-based median diameter (D ₅₀ ; unit μm) of the metal compound fine particles are 5 × 10 ⁵ / D ₅₀ ≦ specific surface area (cm ² / cm ³ ) ≦ 100 × 10 ⁵ / D ₅₀
The single-component developing toner according to claim 1, wherein the following relationship is satisfied. When the content of the metal compound fine particles with respect to the toner is X (mass%) and the toner specific gravity is Y (g / cm ³ ),
0.5 ≦ X × Y ≦ 6.0
The one-component developing toner according to claim 1, wherein the following relationship is satisfied. The toner for one-component development according to any one of claims 1 to 6, wherein the volume-based median diameter D _{50 of the} metal compound fine particles is from 0.5 µm to 3.5 µm. 8. The one-component developing toner according to claim 1, wherein the volume-based D ₉₀ of the metal compound fine particles is larger than 0.5 μm and not larger than 4.0 μm. 12. The toner for one-component development according to claim 1, wherein the volume-based D ₁₀ of the metal compound fine particles is 0.3 μm or more and less than 3.5 μm. 8. The one-component developing toner according to claim 1, wherein the volume-based D ₁₀ of the metal compound fine particles is 0.4 μm or more and less than 3.5 μm. 11. The toner for one-component development according to claim 1, wherein the metal compound fine particles have a specific surface area (cm ² / cm ³ ) of 10 × 10 ⁵ or more and 80 × 10 ⁵ or less. 11. The toner for one-component development according to claim 1, wherein the metal compound fine particles have a specific surface area (cm ² / cm ³ ) of 12 × 10 ⁵ or more and 40 × 10 ⁵ or less.   The toner for one-component development according to any one of claims 1 to 12, wherein the metal compound fine particles contain at least tin oxide.   14. The toner for one-component development according to claim 1, wherein the metal compound fine particles are surface-treated with a silicon compound.   15. The inorganic fine powder is selected from at least silica, titanium oxide, alumina, a composite thereof, or a mixture thereof, and has an average primary particle size of 4 nm to 80 nm. One-component developing toner according to any one of the above. In the triboelectric charging between the metal compound fine particles and the toner carrier, the triboelectric charge amount indicated by the metal compound fine particles is A, and in the triboelectric charging between the toner and the toner carrier, the triboelectric charge amount indicated by the toner is B. Time,
0.05 ≦ | A / B | ≦ 2
The one-component developing toner according to claim 1, wherein the toner is one-component developing toner.   The one-component developing toner according to claim 1, wherein the toner is a magnetic toner having a magnetic material. A charging step for charging the latent image carrier, a latent image forming step for writing image information as an electrostatic latent image on the charging surface of the latent image carrier charged in the charging step, and the electrostatic latent image for the toner When developing and visualizing using a developing device provided with a toner carrier that conveys toner to a development region facing the latent image carrier, the toner carrier comprises at least a substrate and a surface of the substrate. And an image forming method for forming an image by repeating each of the steps, and a development step having a resin coating layer formed of a resin composition.
The toner has at least toner particles, conductive metal compound fine particles and inorganic fine powder on the surface of the toner particles,
The toner particles are formed of at least a binder resin and a colorant,
The toner has a weight average particle diameter of 3 μm or more and 12 μm or less;
In frictional charging between the metal compound fine particles and the toner carrier, the metal compound fine particles exhibit the same charging polarity as the toner, and the absolute value of the triboelectric charge amount is 0.5 (mC / kg) or more and 20 (mC / kg). An image forming method comprising:   19. The image forming method according to claim 18, wherein the toner carrier has at least a substrate and a negatively chargeable resin coating layer formed of a resin composition on the surface of the substrate.   20. The image forming method according to claim 18, wherein in the developing step, the transfer residual toner remaining on the latent image carrier after the transfer step is collected by a toner carrier.   In the developing step, the latent image carrier and the toner carrier are arranged at a predetermined interval, a toner layer is formed on the surface of the toner carrier with a thickness smaller than the interval, and an alternating electric field is applied. 21. The image forming method according to claim 18, wherein the development is performed by transferring the toner to the electrostatic latent image in a developed area.   The latent image carrier is repeatedly used for image formation, and has a mode in which a voltage obtained by superimposing a DC voltage and an AC voltage is applied to the charging member during non-image formation. The frequency of the AC voltage in the mode is 5 to 1000 Hz. The image forming method according to claim 18, wherein the image forming method is an image forming method. a. The charging step for charging the latent image carrier is a charging step for charging the surface of the latent image carrier with a flexible charging member that forms a contact portion with the latent image carrier, and at least the charging member and the latent image carrier. There are conductive fine particles in the contact part with
b. The metal compound fine particles in the toner that has been transferred to the latent image carrier in the development step and remained on the latent image carrier after the transfer step are carried to the contact portion between the charging member and the latent image carrier. Fine particles are supplied,
The image forming method according to claim 18, wherein the image forming method is an image forming method.   24. The resin coating layer formed on the base of the toner carrier comprises at least a binder resin for the coating layer and a substance for making the resin coating layer negatively chargeable. The image forming method according to any one of the above. The binder resin for the coating layer of the resin coating layer formed on the substrate of the toner carrier is partially or entirely of —NH ₂ group, ═NH group, or —NH— bond in the molecular structure. The image forming method according to claim 18, comprising at least one of the above. The coating resin for the coating layer is a phenol resin produced by adding and condensing phenols and aldehydes using a nitrogen-containing compound as a catalyst. In the structure, -NH ₂ group, = NH group, The image forming method according to claim 18, wherein the image forming method is a phenol resin having any one of —NH— bonds.   27. The image forming method according to claim 18, wherein the resin coating layer contains a quaternary ammonium salt compound that is positively charged with respect to at least iron powder.   28. The image forming method according to claim 18, wherein the substance for making the resin coating layer negatively charged is a benzylic acid compound.   The image forming method according to any one of claims 18 to 28, wherein the resin coating layer further includes particles for forming irregularities having a number average diameter of 0.3 to 30 µm in the binder resin for the coating layer.   30. The image forming method according to claim 29, wherein the particles for forming irregularities are spherical resin particles. The image forming method according to claim 30 or 30, wherein the particles for forming the irregularities are conductive spherical particles having a true density of 3 g / cm ³ or less.   32. The image forming method according to claim 18, wherein the negatively chargeable resin coating layer is a conductive resin coating layer in which a conductive substance is further dispersed in the coating layer binder resin.   The image forming method according to claim 32, wherein the conductive resin coating layer further comprises lubricating particles.

Images