JP2008116715A - Image forming apparatus and carrier, toner and developer for use in the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fog due to deterioration in a low temperature and low humidity environment as well as to achieve a long developer life while maintaining a high-reliability image, by using a toner having highly controlled charging characteristics, a development system with little carrier spent and a developer, and highly controlling the fluidity of the toner and developer, and to provide a toner capable of preventing reduction in scooping amount of a developer and good in the following property of a solid image, a carrier and an image forming apparatus capable of printing a high-quality image using this developer. <P>SOLUTION: The toner contains at least a resin, a colorant and a metal salicylate as a charge control agent, wherein a content of a metal element originating in the charge control agent in a toner base particle surface freed of an external additive of the toner is 0.1-1.0 atomic% based on all compositional elements of the surface as measured by XPS (photoelectron spectroscopy). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a carrier, toner, and developer used therefor.

  In an image forming method such as electrophotography, electrostatic recording, and electrostatic printing, in the development process, for example, toner contained in a developer is temporarily attached to an image carrier such as a photosensitive member on which an electrostatic image is formed. Then, after the toner is transferred from the photoreceptor to a transfer medium such as transfer paper in the transfer process, the toner is fixed on the paper surface in the fixing process. The developer is classified into a one-component development method and a two-component development method, and a two-component developer composed of a magnetic carrier and a toner, and a one-component developer that does not require a magnetic carrier (magnetic toner, Non-magnetic toners are known.

Conventionally, as a toner, a dry toner of a kneading and pulverizing method, which is manufactured by melt-kneading a toner binder such as a styrene resin and a polyester resin together with a colorant and the like and finely pulverizing the toner, is used. However, in recent years, there has been an increasing demand for higher image quality, and in order to realize particularly high-definition color image formation, toner particles are being made smaller and spherical. The reproducibility of dots is improved by reducing the particle size, and the developability and transferability can be improved by making the particles spherical.
The toner composed of this resin has a volume average particle diameter of about 10 μm, and externally added inorganic / organic fine particles imparting fluidity to supplement transportability and mixing properties. As a method for adding inorganic fine particles or the like to a toner, a method of adhering inorganic fine particles such as silica, alumina, titanium oxide or the like together with the toner by dry mixing with a mixer or the like is generally used.
In addition, it is known that the chargeability of the toner that contributes most to the developability is generally controlled by using a charge control agent. In particular, in a negatively charged color toner, the toner is not colored and is transparent and good. A salicylic acid metal salt is preferably used as a charge control agent exhibiting charging characteristics (Patent Documents 1 and 2). However, even with the use of the charge control agent, it is difficult to sufficiently satisfy the highly-charged dense charging characteristics, particularly in severe environments (high temperature and high humidity environments) when toner deteriorates under development conditions under high stress. , Or low temperature and low humidity environment).

In addition, the inorganic fine particles externally added to the toner for imparting fluidity are immediately embedded in the toner due to stress with the member in contact with the toner during use, and the fluidity is impaired, so that toner replenishability, developability, charging Deteriorated. In addition, when the toner is not sufficiently mixed, the toner is separated from the toner particles and floats in the image forming apparatus to contaminate the inside of the apparatus, or the toner adheres to an image carrier such as a photosensitive member and becomes a starting point for fixing the toner. There is a problem that filming of the additive occurs.
Furthermore, in recent years, in order to realize particularly high-definition color image formation, a polymerization method produced by suspension polymerization, emulsion polymerization, dispersion polymerization, etc., for the purpose of reducing the toner particle size and spheroidizing. Many methods for granulating toner particles in a liquid including a toner have been studied. In particular, the spherical toner has a problem that it easily rolls on the image carrier and easily passes through an elastomeric cleaning blade, resulting in poor cleaning.

On the other hand, in the case of a two-component development system using a magnetic carrier, one of the important factors affecting the life of the developer is the so-called spent toner component adhering to the carrier. Conventional spent components such as resins, release agents (waxes), charge control agents, external additives, etc. in toner are generally used, and it has been known that these spents reduce the charging ability of the developer. There is no sufficient knowledge about the magnitude of the effect on the carrier charging ability, the adhesion of each component, the adhesion state, etc., and as a result, a long-life development (developer replacement-less) system has been achieved while maintaining high reliability. There wasn't.
In addition, the toner is stressed by a developing screw or the like in the developing machine, which is caused by poor charging uniformity caused by a decrease in the mixing property of the toner and the carrier due to a decrease in the fluidity of the toner when the so-called toner deterioration occurs. There is a problem such as fogging of toner. This phenomenon, particularly in a low temperature and low humidity environment, increases the average charge amount of the developer, thereby increasing the difference in chargeability between the uncharged toner and the charged toner. Although it has been estimated that this is the cause of toner fog, there has been no system capable of highly reducing the deteriorated fog.

Japanese Patent No. 3616835 JP 2006-221156 A

  In view of the above problems, the present invention uses a highly controlled toner, a developing system with a low carrier spent property, and a developer, and highly controls the fluidity of the toner and the developer. Solid image that achieves a long developer life while maintaining highly reliable images, can reduce deterioration fog in low-temperature and low-humidity environments, and can prevent a reduction in developer pumping amount. It is an object of the present invention to provide an image forming apparatus capable of printing a high-quality image using a toner, a carrier, and a developer having good followability.

In order to solve the above problems, the present invention is characterized by the following.
(1) “XPS (photoelectron spectroscopy) of a metal element derived from the charge control agent on the surface of the toner base particle from which the external additive of the toner is removed, wherein the toner includes at least a resin, a colorant, and a metal salt of salicylic acid as a charge control agent. The toner for an image forming apparatus, wherein the content is 0.1 to 1.0 atomic% with respect to all composition elements on the surface ”,
(2) “The dispersion state on the surface of the charge control agent (according to the reflected electron image analysis of FE-SEM) is 0.1% to 2.0% by number of coarse charge control agents having a diameter of φ2 μm or more. The toner for an image forming apparatus according to item (1), wherein:
(3) “The toner for an image forming apparatus according to the item (1) or (2), wherein the charge control agent is a salicylic acid zinc salt”.
(4) Any of the above items (1) to (3), wherein the charge control agent is bis (3,5-di-tertiarybutyl salicylate-O1, O2) zinc The toner for an image forming apparatus according to the above. "
(5) “At least in the premixed state in which the charge control agent before kneading is dispersed in the resin, the crystal size of the charge control agent is sufficiently crushed and mixed to 0.1 to 10 μm. The toner for an image forming apparatus according to any one of Items (1) to (4), wherein:
(6) In any one of the above items (1) to (5), the external additive includes at least one selected from a metal oxide, a metal nitride, and a metal carbide. Toner for image forming apparatus as described in the above. "
(7) The image according to any one of (1) to (6) above, wherein the external additive contains at least titanium oxide having a primary particle number average particle diameter of 5 to 40 nm. Toner for forming apparatus. ",
(8) The toner for an image forming apparatus according to any one of (1) to (7), wherein the toner includes at least a wax having a hydrocarbon straight chain as a release agent. "
(9) “The toner for an image forming apparatus according to any one of Items (1) to (8), wherein the external additive is dry-mixed together with a mixing medium”.
(10) “The toner for an image forming apparatus according to any one of Items (1) to (9),” including a fatty acid metal salt.
(11) “The toner for an image forming apparatus according to any one of Items (1) to (10), which is a color toner”.
(12) The toner according to any one of (1) to (11), wherein the toner particles have an average circularity of 0.94 or more and less than 1.00. Toner for image forming apparatus. "
(13) “The toner particles have a volume average particle diameter of 2.0 to 8.0 μm, and a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn). The toner for an image forming apparatus according to any one of (1) to (12), wherein the toner is in the range of 1.00 to 1.40,
(14) The item (1) to (13), wherein the toner particles have SF-1 in the range of 100 to 180 and SF-2 in the range of 100 to 180. Or the toner for an image forming apparatus according to any one of the items).
(15) “Two-component development in which the image forming apparatus has an image carrier that carries an electrostatic latent image on its surface and a magnetic field generating means fixed inside, and comprises a magnetic carrier and toner on the surface. A developer carrying member comprising a non-magnetic developing sleeve carrying and rotating the developer, and a developing electric field generating means for generating a developing electric field between the image carrying member and the developer carrying member. A developing device for converting the electrostatic latent image on the body into a toner image by the action of the developing electric field using the two-component developer carried on the developer carrying body, The toner for an image forming apparatus according to any one of items (1) to (14), wherein a gap (Gp) between the toner and the developing sleeve is 0.01 mm to 0.7 mm "
(16) “Using the toner according to any one of the above items (1) to (15), an image carrier that carries an electrostatic latent image on its surface, and a magnetic field generating means fixed inside. And developing between the image carrier and the developer carrier, and a developer carrier comprising a nonmagnetic developing sleeve that carries a two-component developer comprising a magnetic carrier and toner on the surface and rotates. A developing electric field generating means for generating an electric field, and using the toner in the two-component developer carried on the developer carrying member for the electrostatic latent image on the image carrying member, In the image forming apparatus including the developing device that forms a toner image by the above, the gap (Gp) between the image carrier and the developing sleeve is 0.01 mm to 0.7 mm. ”
(17) “The image forming apparatus according to (16), wherein the carrier has a weight average particle diameter of 15 (μm) to 45 (μm)”.
(18) The item (16) or (17), wherein the carrier has a resin coating layer on the surface of the core material and contains non-conductive particles in the resin coating layer. ) ”.
(19) “Carrier containing one or more kinds selected from particles of aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfate and zirconium oxide having a weight average particle diameter of 5 to 1000 nm as the non-conductive particles. The image forming apparatus according to item (18), characterized in that:
(20) The above (16) to (19), wherein the toner contains at least one selected from a metal oxide, a metal nitride, and a metal carbide as an external additive. The image forming apparatus according to any one of items 1) to 2).
(21) In the above items (16) to (20), the toner is a toner containing titanium oxide having at least primary particles having a number average particle diameter of 5 to 40 nm as an external additive. The image forming apparatus according to any one of the above ”.
(22) “Image formation according to any one of items (16) to (21), wherein the toner includes at least a wax having a hydrocarbon straight chain as a release agent. apparatus.",
(23) The image forming apparatus according to any one of (16) to (22), wherein the toner is a toner in which an external additive is dry-mixed together with a mixed medium. ,
(24) “The image forming apparatus according to any one of (16) to (23),” wherein the toner is a toner containing a fatty acid metal salt.
(25) “The image forming apparatus according to any one of (16) to (24),” wherein the toner is a color toner.
(26) The toner particles according to any one of (16) to (25), wherein the toner particles are toner having an average circularity of 0.94 or more and less than 1.00. Image forming apparatus. ",
(27) “The toner particles of the toner have a volume average particle diameter of 2.0 to 8.0 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is 1. The image forming apparatus according to any one of (16) to (26), wherein the toner is toner in a range of .00 to 1.40.
(28) The toner particles of the above-mentioned (16) to ((1), wherein the toner particles are toners having SF-1 of 100 to 180 and SF-2 of 100 to 180. 27. The image forming apparatus according to any one of items 27).
(29) “A latent image carrier that carries a latent image, a charging unit that uniformly charges the surface of the latent image carrier, and the surface of the latent image carrier that is charged is exposed based on image data, An exposure unit for writing an electrostatic latent image; a developing unit for supplying toner to the electrostatic latent image formed on the surface of the latent image carrier; and a visible image on the surface of the latent image carrier; The image forming apparatus according to any one of (16) to (28), further comprising: a transfer unit that transfers to a transfer body; and a fixing unit that fixes a visible image on the transfer body.
(30) Any one of (16) to (29) above, further comprising a process cartridge that integrally supports the latent image carrier and at least the developing unit and is detachable from the image forming apparatus main body. The image forming apparatus described in "."
(31) “A carrier having at least magnetism, which is used in the image forming apparatus according to any one of (16) to (29)”.
(32) “A developer containing at least a toner and a carrier, which is used in the image forming apparatus according to any one of Items (16) to (29).”

  As will be apparent from the following detailed and specific description, according to the present invention, highly chargeable toner, development system with low carrier spent property, developer and fluidity of toner and developer are used. By controlling the image quality, it is possible to achieve a long developer life while maintaining a highly reliable image, and to reduce deterioration fog in a low-temperature, low-humidity environment. The present invention provides an extremely excellent effect of providing an image forming apparatus capable of printing a high-quality image using a toner, a carrier, and a developer that can prevent a decrease in the amount and have good followability of a solid image.

  Embodiments of the present invention will be described below. The following description is an example of the best mode of the present invention, and it is easy for a person skilled in the art to make other embodiments within the scope of the claims by making changes and modifications within the scope of the claims. However, this does not limit the scope of the claims.

The electrophotographic toner used in the present invention is a toner for an image forming apparatus in which at least a binder resin and a colorant are included, and an external additive is added to the toner surface.
In the present invention, the three elements of the image forming apparatus (developing apparatus), the developer (carrier), and the toner each exert their functions effectively, and the toner having the highly charged characteristics, which is the above-mentioned problem, is the first problem. It has been found that the conflicting problems of carrier spent, deterioration fog in a low-temperature and low-humidity environment, and prevention of lowering of the developer amount can be achieved at a very high level.
As a toner, firstly, a salicylic acid metal salt, particularly a zinc salicylate, is used as a charge control agent, and an appropriate amount of the charge control agent is disposed on the surface of the toner base so that the toner charge amount distribution, charge rising property, carrier spent property, etc. Control appropriately. The appropriate amount of the toner base particle surface can be evaluated by XPS (photoelectron spectroscopy). The content of the metal element derived from the charge control agent on the surface of the toner base from which the external additive of the toner has been removed is preferably 0.1 to 1.0 atomic%. The charge control agent is not exposed and cannot exhibit charging properties. On the other hand, if it exceeds 1 atomic%, the chargeability is sufficient and preferable. However, the chargeability is too high and the image density does not appear, or the charge of the charge control agent on the carrier and the photoconductor is caused, causing the carrier (developer). This is not preferable because the lifetime of the photoreceptor is reduced.
Since XPS is a technique for surface analysis up to a depth of about 5 nm on the surface, the composition ratio on the surface (generally referred to as 5 nm) that can be measured by surface XPS. Various composition components such as a resin, a wax, a colorant, and a charge control agent exist on the toner surface. When an external additive is present, the surface becomes a component with an extremely large amount of the external additive. It is known that the external additive is buried when the toner deteriorates. In controlling the chargeability of the toner after the deterioration, the chargeability of the toner in the toner base after the deterioration, that is, in the state where no external additive is originally present, is controlled. Need to control. That is, if the charging performance of the toner base is sufficient, the state of the toner after the external additive is buried and detached (a state similar to the base) is good. Therefore, in the present invention, the abundance ratio of the charge control agent on the toner surface is defined in the toner base state from which the external additive, which is a disturbance factor, has been removed. As elements that can be detected by XPS, for example, C and O for resins, C and O for pigments, C and O for waxes, metal elements for charge control goods, and C and O are detected from each component. The elemental composition can be measured such that what atomic%, what atomic% of O, what atomic% of a metal element, and the present invention defines the metal element at this time as 0.1 to 1 atomic%.
In addition, the content of the metal element derived from such a charge control agent in the present invention can be easily and surely achieved by controlling the crystal size of the charge control agent before kneading, for example.

Further, not only the amount of the toner particle surface but also the uniform dispersibility of the charge control agent between the toner particles is very important for improving the uniformity of the toner particles. It is very important to uniformly disperse the charge control agent from the situation in which a very small amount of toner particles cause reverse charging and weak charging to cause scumming, toner scattering, and the like. It is preferable that the number percent of coarse charge control agents having a dispersion state (according to FE-SEM reflection electron image analysis) on the surface of the charge control agent is 0.1 to 2.0 number percent. Here, when the amount is less than 0.1% by number, the coarse charge control agent is reduced, while when finely dispersed in such a manner, the area of the charge site sufficient for the charge control agent to sufficiently charge the toner surface can be maintained. It is not preferable because sufficient charging property cannot be secured. On the other hand, when the coarse charge control agent is 2.0% by number or more, such charge control agent-rich toner particles have an ultra-high charge property, cover the carrier surface, and are appropriately separated from the carrier and transferred to the photoreceptor. In addition to this, the newly introduced toner is prevented from coming into contact with the carrier, and as a result, the newly introduced toner cannot be appropriately charged and becomes a weakly charged and reversely charged toner that causes fogging, toner scattering, and the like.
In order to achieve the above-described dispersion state of the charge control agent, not only the original particle size of the charge control agent but also the premix process with the resin and other raw materials before kneading is particularly important. It has been found that when the control agent is sufficiently pulverized and mixed, the dispersion state inside the toner after kneading is uniform and good. Naturally, the kneading state is also important, and it is important to knead and disperse for a sufficient time at a low temperature at which kneading stress increases. It has been clarified from various studies that kneading at a high temperature lowers the melt viscosity of the resin and lowers the stress in the kneaded state, so that the resin cannot be sufficiently kneaded.

  The developing device according to the present invention has an image carrier that carries an electrostatic latent image on the surface and a magnetic field generating means fixed inside, and carries a two-component developer comprising a magnetic carrier and toner on the surface. A developer carrying member comprising a rotating non-magnetic developing sleeve, and a developing electric field generating means for generating a developing electric field between the image carrying member and the developer carrying member. A developing device that converts an electrostatic latent image into a toner image by the action of the developing electric field using toner in a two-component developer carried on the developer carrying member. However, it is easy to give deterioration stress to the developer. While controlling the distance between the image carrier and the developing sleeve, the development gap (Gp), it is easy to impart effective chargeability, while in the toner in the developer, the toner charge control agent and the additive are buried or Detachment is likely to occur, and at the same time, the coating film of the carrier is scraped and carrier spent from the toner components (resin, wax, charge control agent, pigment, external additive, additive, etc.) is likely to occur. Also, photoconductor filming derived from similar toner components is likely to occur. Therefore, in order to improve the high image quality, for example, fog (background stain), toner scattering, transfer omission, transfer dust (high transfer rate), etc., the charge rising property and charge retention property of the developer are essential. Although it is effective to use a development system, there are new countermeasures for the carrier or toner to achieve other problems (carrier spent, toner additive desorption, embedding, photoreceptor filming and cleaning resulting from these). Necessary.

Among toner charge control agents and external additives, it is particularly important to control the carrier surface adhesion amount of silica as a developing device, a developer, and a carrier used therefor. It is required to be a certain controlled low spent carrier. In particular, the coverage of the silica carrier surface is a problem as the reason why it is necessary to control the amount of silica adhered. In the two-component development system, toner is imparted with triboelectric charge by frictional charging with the carrier surface, but silica with excellent coating properties covers the carrier surface, reducing the triboelectric charging site on the carrier surface, and developer. As a result, good chargeability cannot be maintained. In addition, even when non-conductive particles are present on the carrier surface and are not smooth, it is understood that the fluidity and adhesion of silica will function fluidly on the carrier surface and form a film easily. I came. Thereafter, there is little detachability from the surface of the carrier, and in a toner system containing a wax, in particular, the wax promotes carrier adhesion by the action of an adhesive and forms strong adhesion.
As means for controlling the adhesion to the carrier and the flowability of the developer, it is particularly important to control the carrier particle size, the coating resin configuration, the contained filler (non-conductive particles), the filler particle size, and the like.

  On the other hand, as a toner, various studies have been conducted for the purpose of reducing the transfer of the toner external additive to the carrier, and the existence state or fluidity of the toner charge control agent is highly controlled within a specified range. It has been found that carrier spent property, photoreceptor filming property, and toner deterioration fog are drastically improved. The highly controlled fluidity of the toner not only acts as a cause of carrier spent, photoconductor filming, transfer failure, etc., but also causes slight changes in chargeability and chargeability distribution, causing deterioration fog. Estimated.

(Developer)
In the image forming apparatus according to the present embodiment, a charging device, an exposure device, a developing device, a transfer device, a cleaning device, and the like are sequentially arranged around a photoconductor as an image carrier. In addition, a paper feeding / conveying device that feeds the transfer paper from the paper feeding tray and a fixing device that fixes the toner onto the transfer paper after the transfer paper on which the toner image has been transferred are separated from the photoreceptor. In the image forming apparatus configured as described above, the surface of the rotating photosensitive member is uniformly charged by the charging device, and then irradiated with the laser beam of the exposure device based on the image information to form a latent image on the photosensitive member. Form. A toner image is formed by attaching toner charged by a developing device to the electrostatic latent image formed on the photoreceptor. On the other hand, the transfer paper is fed from a paper feed tray by a paper feed / conveying device, and then transported to a transfer portion where the photoconductor and the transfer device face each other. Then, the transfer device applies a charge having a polarity opposite to that of the toner image on the photoconductor to the transfer paper, thereby transferring the toner image formed on the photoconductor to the transfer paper. Next, the transfer paper is separated from the photoconductor, sent to a fixing device, and an image is obtained by fixing toner on the transfer paper.

FIG. 1 is a schematic configuration diagram of a developing device (1) of an image forming apparatus according to the present embodiment. The developing device (1) employed in the image forming apparatus will be described in detail with reference to FIG. The developing device (1) is disposed on the side of the photoreceptor (8), and serves as a developer carrying member that carries a two-component developer (hereinafter referred to as “developer”) including toner and a magnetic carrier on the surface. The non-magnetic developing sleeve (7) is provided. The developing sleeve (7) is attached so as to be partially exposed from an opening formed on the photosensitive member (1) side of the developing casing, and is rotated in the direction of arrow (b) in the drawing by a driving device (not shown). The material of the developing sleeve is not particularly limited as long as it is used in a normal developing device, and nonmagnetic materials such as stainless steel, aluminum, ceramics, and those coated thereon are used. Further, the shape of the developing sleeve is not particularly limited. Also, a magnet roller (not shown) composed of a fixed magnet group as a magnetic field generating means is fixedly arranged inside the developing sleeve (7). Further, the developing device (1) includes a doctor (9) as a developer regulating member made of a rigid body that regulates the amount of developer carried on the developing sleeve (7). A developer accommodating portion (4) for accommodating a developer is formed on the upstream side of the rotation direction of the developing sleeve (7) with respect to the doctor (9), and the developer in the developer accommodating portion (4) is agitated. First and second stirring screws (5) and (6) to be mixed are provided. Further, a toner replenishing port (23) disposed above the developer accommodating portion (4), a toner hopper (2) filled with toner to be replenished to the developer accommodating portion (4), and a toner replenishing port (23). And a toner flow device (3) for connecting the toner hopper (2).
In the developing device (1) configured as described above, the developer in the developer container (4) is agitated by rotating the first and second agitating screws (5) and (6), and the toner and the magnetic The carrier is frictionally charged with opposite polarities. This developer is supplied to the peripheral surface of the developing sleeve (7) that is rotationally driven in the direction of the arrow (b), and the supplied developer is carried on the peripheral surface of the developing sleeve (7). By rotation, it is conveyed in the rotation direction (arrow (b) direction). Next, the amount of the conveyed developer is regulated by the doctor (9), and the regulated developer is conveyed to a development area where the photoconductor (8) and the development sleeve (7) face each other. In this developing area, the toner in the developer is electrostatically transferred to the electrostatic latent image on the surface of the photoreceptor (8), and the electrostatic latent image is visualized as a toner image.
Here, the distance (development gap; Gp) between the image carrier (8) and the developing sleeve (7) is more preferably 0.01 mm to 0.7 mm, and in the case of less than 0.01, the developer This is not preferable because the transportability of the sheet is reduced and the uniformity of the solid image is decreased. On the other hand, when it exceeds 0.7 mm, the charge rising property and retention of the developer are likely to be lowered, which is not preferable.

(Quantification of charge control agent on toner base surface by XPS)
In the present invention, the content of the metal element derived from the charge control agent on the surface of the toner base from which the external additive of the toner is removed can be determined by an XPS (X-ray photoelectron spectroscopy) apparatus. In this invention, it calculated | required with the following apparatuses and conditions.
(1) Pretreatment
(1-1) Drywell (Film, photographic paper drainer, product name Fuji Drywell (EG400123) manufactured by Fuji Film Co., Ltd.) 0.5ml, Isoton 100ml, add 4g of toner and mix well with 50 shakes. Allow to stand for 1 hour or longer (Isoton = ISOTON-II (about 1% NaCl aqueous solution prepared with Coulter's electrolyte using primary sodium chloride).
(1-2) After stirring by hand shaking 30 times, the mixture is dispersed for 1 minute at 20 W using a homogenizer to release the toner external additive.
(1-3) The dispersion is subjected to suction filtration, the external additive is separated from the toner, and the obtained toner base is dried.
(1-4) Ultrasonic irradiation conditions of homogenizer (VCX-750 manufactured by Sonics & Materials) ・ Vibration time 60 seconds continuous ・ Amplitude 20W (39%)
・ Vibration start temperature 23 ± 1.5 ℃
(1-5) The toner base was packed in an aluminum dish and lightly pressed from above and measured.
(2) Equipment
PHI 1600S X-ray photoelectron spectrometer (3) Measurement conditions X-ray source MgKα (100W)
Analysis area 0.8 × 2.0mm

(Evaluation of dispersion state of charge control agent by FE-SEM backscattered electron image analysis)
In the present invention, the dispersion state of the charge control agent on the surface of the toner base was evaluated using the following apparatus and conditions. The pretreatment for removing the external additive was performed in the same manner as the XPS described above.
(1) Device: Zeiss Ultra55 FE-SEM (scanning electron microscope), backscattered electron observation (2) acceleration voltage 0.8 kV, undeposited observation (3) 4-5 visual field measurement at 2000 times magnification (4) image processing Software: Image-Pro Plus 4.5.1 (Media Cybernetics, Inc.) was used for binarized image processing analysis of a metal charge control agent detected as white contrast. The average dispersion diameter was calculated from the area of 80 extracted charge control agent particles on the surface of the toner base particles, and the number% of 2 μφ or more was calculated by statistical processing.

(Evaluation of dispersion diameter of charge control agent in premix state)
The crystal size of the charge control agent in a premixed state in which the charge control agent before kneading was dispersed in the resin was evaluated as follows.
(1) Equipment: Ultra55 FE-SEM (scanning electron microscope) manufactured by Zeiss, backscattered electron observation (2) acceleration voltage 0.8 kV, undeposited observation (3) 4 to 5 visual field measurements at 1000 times magnification (4) An image processing software; Image-Pro Plus 4.5.1 (Media Cybernetics, Inc.), binarized image processing analysis of a metal charge control agent detected as white contrast was performed to calculate an average dispersion diameter of 100 particles.

(Charge control agent)
In the present invention, a typical example of a salicylic acid zinc salt or a zinc salt of a salicylic acid derivative as an example of a salicylic acid metal salt used as a charge control agent contained in a toner is represented by the following general formula (2).

（式中、Ｒ１，Ｒ２及びＲ３は水素又は炭素数１〜１０のアルキル基或いはアリル基がよい。Ｒ１，Ｒ２及びＲ３は同時に同じであっても異なってもよい。ＭはＺｎである。）
より好ましくは、式（３）で示されるビス（3,5-ジ・ターシャリーブチルサリチラト−O1,O2）亜鉛である。

(In the formula, R1, R2 and R3 are preferably hydrogen, an alkyl group having 1 to 10 carbon atoms, or an allyl group. R1, R2 and R3 may be the same or different at the same time. M is Zn.)
More preferred is bis (3,5-di-tert-butylsalicylate-O1, O2) zinc represented by the formula (3).

かかる一般式で表された金属塩はＣＬＡＲＫ，Ｊ．Ｌ．ＫａＯ，Ｈ（１９４８）Ｊ．Ａｍｅｒ．Ｃｈｅｍ，Ｓｏｃ ７０，２１５１に記載された方法によって容易に合成することができる。例えば溶媒中に２モルのサリチル酸ナトリウム塩（サリチル酸誘導体のナトリウム塩を含む）と１モルの塩化亜鉛とを添加し混合し加温して撹拌することにより亜鉛塩を得る。トナー中に占める前記亜鉛塩の量は、結着樹脂１００重量部に対し０．１〜１０重量部、好ましくは０．５〜５重量部程度である。

Metal salts represented by such general formulas are described in CLARK, J .; L. KaO, H (1948) J. MoI. Amer. It can be easily synthesized by the method described in Chem, Soc 70, 2151. For example, 2 mol of salicylic acid sodium salt (including the sodium salt of a salicylic acid derivative) and 1 mol of zinc chloride are added to a solvent, mixed, heated and stirred to obtain a zinc salt. The amount of the zinc salt in the toner is 0.1 to 10 parts by weight, preferably about 0.5 to 5 parts by weight, with respect to 100 parts by weight of the binder resin.

(Career)
The carrier of the present invention has a weight average particle size of 15 (μm) or more and 45 (μm) or less from the viewpoint of fluidity, triboelectric chargeability with toner, and coverage of toner related to toner scattering. preferable. When the thickness is less than 15 μm, carrier adhesion to the photosensitive member occurs, which may cause image omission and the like. On the other hand, if it exceeds 45 μm, it is not preferable in terms of latent image reproducibility, toner scattering property, etc., in combination with toner, particularly small particle size toner.
Further, it is more preferable that the carrier has a resin coating layer on the surface of the core material, and the resin coating layer contains non-conductive particles. Non-conductive particles are more preferable because they generate moderate irregularities on the carrier surface and prevent the carrier spent property, and also have the effect of scraping the spent adhering to the carrier. In addition, uniform chargeability with excellent riseability can be secured, and the margin for fogging can be improved.
The non-conductive particles may be a carrier using one or two or more kinds selected from aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfate, and zirconium oxide particles having a weight average particle diameter of 5 to 1000 nm. It is more preferable from the viewpoints of spent removability, carrier film strength, charge rising property, fluidity, retention and the like.

(Non-conductive particles of carrier)
Furthermore, by containing non-conductive particles, it is possible to adjust the resistance while maintaining the film strength of the coating layer, the surface shape of the carrier, and the like. Examples of the nonconductive particles herein include inorganic oxide particles, resin fine particles, and the like (aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfate, zirconium oxide, etc.).
The non-conductive particles in the present invention exceed 500 Ω · cm, and are different from the general definition of non-conductive particles.

Furthermore, the improvement effect is remarkable when the volume specific resistance of the carrier is 10 [Log (Ω · cm)] or more and 16 [Log (Ω · cm)] or less. When the volume resistivity is less than 10 [Log (Ω · cm)], carrier adhesion occurs in the non-image area, which is not preferable. On the other hand, if the volume resistivity exceeds 16 [Log (Ω · cm)], the edge effect is unacceptably deteriorated to an unacceptable level. In addition, when it falls below the measurable lower limit of the high resist meter, the volume specific resistance value is not substantially obtained, and it will be treated as a breakdown.
The volume resistivity referred to in this specification is a value obtained by measuring a resistance value measured with a high resist meter 30 seconds after DC1000V is applied between both electrodes after a carrier is injected between parallel electrodes separated by a gap of 2 mm. The value converted into volume resistivity.

Furthermore, when the weight average particle size is 15 (μm) or more and 45 (μm) or less, the improvement effect is remarkable. When the weight average particle size is less than 15 μm, problems such as carrier adhesion occur due to the decrease in the uniformity of the particles and the failure to establish a technique that can be fully used on the machine side. On the other hand, if it exceeds 45 μm, the reproducibility of image details is poor and a fine image cannot be obtained, which is not preferable.
Furthermore, the improvement effect is remarkable because at least the binder resin of the carrier coating layer is a silicone resin. This is because the silicone resin has a low surface energy, so that it is difficult to spend the toner component, and it is difficult to accumulate the spent component due to film scraping.

  As used herein, the term “silicone resin” refers to a generally known silicone resin, such as straight silicone consisting only of organosilosan bonds, and silicone resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. Examples include but are not limited to these. For example, examples of commercially available straight silicone resins include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical, SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicon. In this case, it is possible to use the silicone resin alone, but it is also possible to simultaneously use other components that undergo a crosslinking reaction, charge amount adjusting components, and the like. Further, as modified silicone resins, KR206 (alkyd modified), KR5208 (acrylic modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical, SR2115 (epoxy modified) manufactured by Toray Dow Corning Silicon Co., Ltd. , SR2110 (alkyd modified) and the like.

  Furthermore, the improvement effect is remarkable because at least the binder resin of the carrier coating layer is an acrylic resin. Acrylic resin has strong adhesiveness and low brittleness, so it has very excellent properties in terms of wear resistance, and it is difficult for deterioration such as coating film scraping and film peeling to occur. In addition, the particles contained in the coating layer such as conductive particles can be firmly held due to the strong adhesiveness. In particular, a powerful effect can be exhibited in holding particles having a particle size larger than the coating layer thickness.

  The acrylic resin as used herein refers to a resin having an acrylic component, and is not particularly limited. In addition, it is possible to use the acrylic resin alone, but it is also possible to use at least one other component that undergoes a crosslinking reaction at the same time. Examples of the other component that undergoes a crosslinking reaction include an amino resin and an acidic catalyst, but are not limited thereto. The amino resin here refers to guanamine, melamine resin and the like, but is not limited thereto. Moreover, what has a catalytic action can be used with the acidic catalyst said here. For example, it has a reactive group such as a fully alkylated type, a methylol group type, an imino group type, and a methylol / imino group type, but is not limited thereto.

  Furthermore, at least the binder resin is an acrylic resin and a silicone resin, so that the improvement effect is remarkable. As described above, acrylic resin has a very excellent property of abrasion resistance due to its strong adhesiveness and low brittleness, but on the other hand, it has a high surface energy, so it can be easily spent with toner. This is because the combination may cause problems such as a decrease in charge amount due to accumulation of toner component spent. In this case, this problem can be solved by using together a silicone resin that has an effect that it is difficult to spend the toner component due to the low surface energy and the accumulation of the spent component is difficult to progress due to film scraping. However, since the silicone resin has weak adhesiveness and high brittleness, it also has a weak point that it has poor wear resistance. Therefore, it is important to obtain a good balance between the properties of these two resins. It is possible to obtain a coating film having wear characteristics.

  The amount of the binder resin for carrier coating in the present invention is preferably in the range of 0.1 to 1.5% by weight. When the content is less than 0.1% by weight, there is almost no coating film, so that the effect of the coating film cannot be sufficiently exhibited, which is not preferable. On the other hand, when it exceeds 1.5% by weight, it is not preferable because the amount of chipping of the film tends to increase as the film thickness increases, but it is not limited thereto. The binder resin content referred to here is expressed by the following equation.

  Furthermore, the improvement effect is remarkable when the content ratio of the particles is 10 (wt%) or more and 70 (wt%) or less. When the amount is less than 10% by weight, since the proportion of the particles is smaller than the proportion of the binder resin on the surface of the carrier particles, the effect of reducing contact with a strong impact on the binder resin is small. This is not preferable because sufficient durability cannot be obtained. On the other hand, when the amount is more than 70% by weight, since the proportion of the particles is excessive as compared with the proportion of the binder resin on the carrier surface, the proportion of the binder resin that is a charging generation point is insufficient. Thus, sufficient charging ability cannot be exhibited. In addition, since the amount of particles is too much compared to the amount of binder resin, the ability to hold particles by the binder resin becomes insufficient, and the particles are likely to be detached. It is not preferable because the properties cannot be obtained. The particle content referred to here is the total content of conductive particles and non-conductive particles, and is represented by the following formula.

Furthermore, when the magnetic moment at 1000 (10 ³ / 4π · A / m) is 40 (Am ² / kg) or more and 90 (Am ² / kg) or less, the improvement effect is remarkable. By setting this range, the retention force between the carrier particles is properly maintained, so that the dispersion (mixing) of the toner into the carrier or developer is quickly and well improved, but the magnetic moment at 1 KOe is less than 40 Am ² / kg. In this case, carrier adhesion occurs due to insufficient magnetic moment, which is not preferable. On the other hand, when the magnetic moment at 1 KOe exceeds 90 Am ² / kg, the ears of the developer formed at the time of development become too hard, so that the reproducibility of image details is poor and a fine image cannot be obtained, which is not preferable.

  Furthermore, the improvement effect is remarkable by using an electrophotographic developer combining at least a toner composed of a binder resin and a colorant and the carrier of the present invention. This is because the carrier of the present invention can obtain a high-definition image and has a longer life, and therefore the developer using the carrier of the present patent can obtain excellent quality. In particular, when combined with a toner containing a release agent, the carrier of the present invention having excellent spent properties and the like is preferable because it has a long life.

(External toner additive)
Examples of inorganic fine particles that are external additives added to the toner of the present invention include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, and oxide. Tin, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. Can be mentioned. Among these, a metal oxide, a metal nitride, and a metal carbide are preferable, and an external additive having a number average particle size in the range of 8 to 80 nm and an external additive in the range of 120 to 300 nm are preferable. Among the inorganic fine particles, silica, alumina, and titanium oxide are preferable, and silica and titanium oxide are particularly preferable. Further, it is more preferable in terms of toner chargeability and fluidity that at least the primary particles contain titanium oxide having a primary particle number average particle size of 5 to 40 nm. The inorganic fine particles are more preferably used in an amount of 0.01 to 5% by weight based on the toner base.
As a means of highly controlling the fluidity of the toner, not only the control of the production conditions of the external additive, but also the crushing, sieving and the like after the production of the external additive are effective. The adhesion state is also important.

As the external additive, inorganic fine particles or hydrophobic treated inorganic fine particles can be used in combination, but the average particle size of the hydrophobized primary particles is 1 to 20 nm, more preferably 6 to 15 nm (specific surface area by BET method). 100 to 400 m ² / g) and 30 to 150 nm, more preferably 90 to 130 nm ( ²⁰ to 100 m ² / g specific surface area by BET method) and at least two kinds of large particle size inorganic fine particles More preferably, the above is present on the toner particle surface. More preferably, the small particle size inorganic fine particles are silica or titanium oxide, and both are more preferable. Silica is more preferable for the large particle size inorganic fine particles. Further, silica produced by a wet method such as a sol-gel method is more preferable. Further, it is more preferable that inorganic fine particles having a medium particle diameter of 20 to 50 nm (specific surface area by BET method of 40 to 100 m ² / g), more preferably silica, are further present on the toner particle surface.
As the inorganic fine particles, known ones can be used if the conditions are satisfied. For example, silica fine particles, hydrophobic silica, fatty acid metal salts (such as zinc stearate and aluminum stearate), metal oxides (such as titania, alumina, tin oxide, and antimony oxide), fluoropolymers, and the like may be contained.
Particularly suitable additives include hydrophobized silica, titania, titanium oxide, and alumina fine particles. Silica fine particles include HDK H 2000, HDK H 2000/4, HDK H 2050EP, HVK21, HDK H 1303 (above Hoechst) and R972, R974, RX200, RY200, R202, R805, and R812 (above Nippon Aerosil). Further, as titania fine particles, P-25 (Nippon Aerosil), STT-30, STT-65C-S (above Titanium Industry), TAF-140 (Fuji Titanium Industry), MT-150W, MT-500B, MT-600B MT-150A (taker above). Particularly, the hydrophobized titanium oxide fine particles include T-805 (Nippon Aerosil), STT-30A, STT-65S-S (above Titanium Industry), TAF-500T, TAF-1500T (above Fuji Titanium Industry), MT -100S, MT-100T (above Taka), IT-S (Ishihara Sangyo), etc.

Hydrophobized oxide fine particles, silica fine particles, titania fine particles, and alumina fine particles are obtained by treating hydrophilic fine particles with a silane coupling agent such as methyltrimethoxysilane, methyltriethoxysilane, or octyltrimethoxysilane. Can do. In addition, silicone oil-treated oxide fine particles and inorganic fine particles obtained by treating silicone oil with heat if necessary to treat it with inorganic fine particles are also suitable.
Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, and amino-modified silicone. Oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic, methacryl-modified silicone oil, α-methylstyrene-modified silicone oil and the like can be used. Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, quartz sand, clay, mica, and silica ash. Examples thereof include stone, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, parium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Of these, silica and titanium dioxide are particularly preferred. The addition amount can be 0.1 to 5% by weight, preferably 0.3 to 3% by weight, based on the toner. The average particle size of the primary particles of the inorganic fine particles is 100 nm or less, preferably 3 nm or more and 70 nm or less. If it is smaller than this range, the inorganic fine particles are buried in the toner particles, and their functions are not easily exhibited. On the other hand, if it is larger than this range, the surface of the photoreceptor is undesirably damaged.

  In addition, polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, methacrylic acid ester and acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine and nylon, thermosetting resin And polymer particles.

Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .
Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles, etc. And polymer fine particles produced by soap-free emulsion polymerization. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

  As a method of adding to the toner, not only dry external addition treatment using a Henschel mixer, Q mixer, etc., but also wet external addition treatment (solvent, water (containing an activator for improving wettability as required)). Adhesion is also effective.

  The external additive is mixed into the base toner. The external additive is added to the base toner by mixing and stirring the base toner and the external additive using a mixer while the external additive is crushed on the toner surface. It may be a dry mix to be coated. At this time, it is important in terms of durability that external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the surface of the base toner particles. As these addition conditions, the blade shape of the mixer, the number of rotations, the mixing time, the number of times of mixing, the amount of the external additive, the amount of the base toner, and the surface properties (unevenness, hardness, viscoelasticity, etc.) of the base toner are important.

Moreover, an inorganic fine particle adhesion process can be performed in a liquid as wet mixing. This step may be performed after the toner particles are formed in water and the used surfactant and the like are removed by washing. Excess surfactant present in water is removed by solid-liquid separation such as filtration and centrifugation, and the resulting cake and slurry are redispersed in an aqueous medium. Further, inorganic fine particles are added and dispersed in the slurry. Inorganic fine particles can be dispersed in an aqueous dispersion in advance. At this time, if the surfactant is dispersed using a reverse polarity surfactant, the adhesion to the toner particle surface is more efficiently performed. If the inorganic fine particles are hydrophobized and are difficult to disperse in the aqueous dispersion, the inorganic fine particles may be dispersed after the interfacial tension is lowered by using a small amount of alcohol or the like to facilitate wetting. Thereafter, an aqueous surfactant solution having a reverse polarity is gradually added with stirring. The reverse polarity surfactant is preferably used in an amount of 0.01 to 1% by weight based on the solid content of the toner particles. By adding a surfactant having a reverse polarity, the charge of the inorganic fine particle dispersion in water can be neutralized, and the inorganic fine particles can be aggregated and adhered to the toner particle surfaces. The inorganic fine particles are preferably used in an amount of 0.01 to 5% by weight based on the solid content of the toner particles.
The inorganic fine particles adhered to the toner surface can be fixed to the toner surface by heating the slurry thereafter to prevent detachment. At that time, it is desirable to heat at a temperature higher than the Tg of the resin constituting the toner. Further, heat treatment may be performed after drying while preventing aggregation.
Further, in order to reduce the coefficient of friction on the surface of the photoreceptor and improve the cleaning property, a metal stearate may be mixed as a lubricant with the toner of the present invention. Zinc stearate is preferred.

Next, a method for producing toner using the above external additive will be described.
In recent years, in order to obtain high-definition and high-quality images, there is a tendency to further reduce the particle diameter of toner. Although the particle size may be reduced by a manufacturing method based on ordinary kneading and pulverization methods, the cost is extremely high from the viewpoint of energy used and yield, and there is a pulverization limit of the particle size. I can not cope.
Therefore, as a method for solving this problem, a polymerized toner production method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dispersion polymerization method has been proposed.

The toner according to the present invention has a volume average particle diameter of 2 to 8 μm, and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is in the range of 1.00 to 1.40. It is preferable that it exists in.
By using a toner having a small particle diameter, the toner can be densely attached to the latent image. However, when the volume average particle diameter is smaller than the range of the present invention, in the two-component developer, the toner is fused to the surface of the magnetic carrier during a long period of stirring in the developing device, and the charging ability of the magnetic carrier is lowered. On the contrary, when the volume average particle diameter of the toner is larger than the range of the present invention, it becomes difficult to obtain a high-resolution and high-quality image, and when the balance of the toner in the developer is performed. In many cases, the variation in toner particle size becomes large.
Further, by narrowing the particle size distribution, the toner charge amount distribution becomes uniform, a high-quality image with little background fogging can be obtained, and the transfer rate can be increased. However, it is not preferable that Dv / Dn exceeds 1.40 because the charge amount distribution becomes wide and the resolving power decreases.
The average particle diameter and particle size distribution of the toner can be measured using a Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). In the present invention, a Coulter counter TA-II type was used, connected to an interface (manufactured by Nikka Giken) and a personal computer (PC9801: manufactured by NEC) to output the number distribution and volume distribution.

(Particle size measurement)
As an apparatus for measuring the particle size distribution of toner particles by the Coulter counter method, there are Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using first grade sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter of the toner can be obtained.
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

The toner according to the present invention preferably has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180.
FIG. 2 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (A). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.

ＳＦ−１の値が１００の場合トナーの形状は真球となり、ＳＦ−１の値が大きくなるほど不定形になる。
また、形状係数ＳＦ−２は、トナーの形状の凹凸の割合を示すものであり、下記式（Ｂ）で表される。トナーを２次元平面に投影してできる図形の周長ＰＥＲＩの二乗を図形面積ＡＲＥＡで除して、１００π／４を乗じた値である。

When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.
The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (B). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.

ＳＦ−２の値が１００の場合トナー表面に凹凸が存在しなくなり、ＳＦ−２の値が大きくなるほどトナー表面の凹凸が顕著になる。

When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.

When the shape of the toner is close to a sphere, the contact between the toner and the toner or the toner and the photoreceptor (1) is close to a point contact, so that the adsorbing force between the toners becomes weak and the fluidity becomes high. And the photosensitive member (1) also become weaker and the transfer rate becomes higher. On the other hand, since spherical toner tends to enter the gap between the cleaning blade (7a) and the photoreceptor (1), the toner shape factor SF-1 or SF-2 should be large to some extent. Further, when SF-1 and SF-2 are increased, toner is scattered on the image and the image quality is lowered. For this reason, it is preferable that SF-1 and SF-2 do not exceed 180.
Specifically, the shape factor is measured by randomly sampling 300 SEM images of toner obtained by FE-SEM (S-4200) manufactured by Hitachi, Ltd. And introduced into an image analysis apparatus (Luzex AP) manufactured by Nireco, Inc.

(Pulverized toner and toner production method)
The manufacturing method of the pulverized toner of the present invention includes a kneading step, a pulverizing step, and a classification step, and further includes other steps as necessary.
The toner of the present invention is manufactured by the toner manufacturing method of the present invention.
Hereinafter, the details of the toner of the present invention will be clarified through the description of the toner production method of the present invention.

-Kneading process-
The kneading step is a step of kneading a toner material containing at least a binder resin, a colorant, and a charge control agent.

(Binder resin)
As the binder resin, a polyester resin suitable as a binder resin for a full color toner is used from the viewpoint of color development and image strength. In a color image, several types of toner layers are stacked several times, so that the toner layer becomes thick, and cracks and defects of the image due to insufficient strength of the toner layer occur, or an appropriate gloss is lost. For this reason, a polyester resin is used to maintain an appropriate gloss and excellent strength. The polyester resin can be generally obtained by an esterification reaction of a polyhydric alcohol and a polycarboxylic acid.

  Among the monomers constituting the polyester resin, the alcohol monomer includes a trifunctional or higher polyfunctional monomer, for example, ethylene glycol, diethylene glycol triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol. Diols such as 1,4-butadieneol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol; bisphenol A, hydrogenated bisphenol A, polyoxypropylenated bisphenol Bisphenol A alkylene oxide adducts such as A; other dihydric alcohols, or sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripe Taerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, tri Examples include methylolpropane, 1,3,5-trihydroxybenzene, and other trihydric or higher polyhydric alcohols.

  Among these monomers, those using a bisphenol A alkylene oxide adduct as a main component monomer are particularly preferably used. When the bisphenol A alkylene oxide adduct is used as a constituent monomer, a polyester having a relatively high glass transition point is obtained due to the nature of the bisphenol A skeleton, and the copy blocking resistance and heat resistant storage stability are good. In addition, the presence of alkyl groups on both sides of the bisphenol A skeleton acts as a soft segment in the polymer, and the color developability and image strength during toner fixing are improved. Of the bisphenol A alkylene oxide adducts, those having an ethylene group or a propylene group are preferably used.

  Examples of the acid monomer among the monomers constituting the polyester resin include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, and adipine. Alkenyl succinic acids or alkyl succinic acids such as acids, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, n-dodecyl succinic acid, anhydrides, alkyl esters of these acids, or other divalent carboxylic acids; 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxylic acid Lu-2-methyl-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, or anhydrides thereof, alkyl ester, alkenyl ester, aryl ester Or other trivalent or higher carboxylic acids.

  Specific examples of the alkyl group, alkenyl group or aryl ester include 1,2,4-benzenetricarboxylic acid, trimethyl 1,2,4-benzenetricarboxylate, triethyl 1,2,4-benzenetricarboxylate, 1,2 , 4-benzenetricarboxylic acid tri-n-butyl, 1,2,4-benzenetricarboxylic acid isobutyl, 1,2,4-benzenetricarboxylic acid tri-n-octyl, 1,2,4-benzenetricarboxylic acid tri-2-ethylhexyl, 1,2,4-benzenetricarboxylic acid tribenzyl, 1,2,4-benzenetricarboxylic acid tris (4-isopropylbenzyl), and the like.

It is known that the chargeability and acid value of the polyester resin are approximately proportional to each other, and it is known that the higher the acid value, the greater the negative chargeability of the resin. At the same time, it affects the environmental stability of charging.
That is, when the acid value is high, the charge amount is high under low temperature and low humidity, and the charge amount is low under high temperature and high humidity. difficult. Therefore, the acid value of the polyester resin is 20 KOHmg / g or less, and more preferably 5 KOHmg / g or less.

Here, the acid value (AV) in the present invention is specifically determined by the following procedure.
Measuring device: potentiometric automatic titrator DL-53 Titrator (Metler Toledo)
Electrode used: DG113-SC (manufactured by METTLER TOLEDO)
Analysis software: LabX Light Version 1.00.000
Calibration of the apparatus: Use a mixed solvent of 120 mL of toluene and 30 mL of ethanol.
Measurement temperature: 23 ° C
Measurement conditions: As shown below
Speed [%] 25
Time [s] 15
EQP titration
Titrant / Sensor
Titrant CH3 ONa
Concentration [mol / L] 0.1)
Sensor DG115
Unit of measurement mV
Predispensing to Volume
Volume [mL] 1.0
Wait time [s] 0
Titrant addition Dynamic
dE (set) [mV] 8.0
dV (min) [mL] 0.03
dV (max) [mL] 0.5
Measurement mode Equilibrium controlled
dE [mV] 0.5
dt [s] 1.0
t (min) [s] 2.0 t (max) [s] 20.0
Recognition
Threshold 100.0
Steppes jump only No
Range No
Tendency None
Termination
at maximum volume [mL] 10.0
at potential No
at slope No
after number EQPs Yes
n = 1
comb. termination conditions No
Evaluation
Procedure Standard
Potential 1 No
Potentialial 2 No
Stop for revaluation No

(Measurement method of acid value)
Measurement is performed under the following conditions in accordance with the measurement method described in JIS K0070-1992.
Sample preparation: 0.5 g of toner (0.3 g for ethyl acetate soluble component) is added to 120 mL of toluene and dissolved by stirring at room temperature (23 ° C.) for about 10 hours. Further, 30 mL of ethanol is added to prepare a sample solution.
The measurement can be calculated by the apparatus described above, but specifically, the calculation is performed as follows. Titrate with a standardized N / 10 KOH-alcohol standard solution, and determine the acid value from the consumption of the standard solution by the following calculation.

（ただし、Ｎは、Ｎ／１０ ＫＯＨのファクター）

(However, N is a factor of N / 10 KOH)

  Furthermore, the polyester resin is particularly free of tetrahydrofuran (THF), and in the molecular weight distribution in gel permeation chromatography (GPC), the content of components having a molecular weight of 500 or less is preferably 4% by mass or less. The mass% is more preferable. Moreover, it has one peak in the area | region of molecular weight 3,000-9,000. When THF-insoluble matter enters, the glossiness is lowered and the transparency is lowered, and a high-quality image cannot be obtained when an OHP sheet is used. Further, when the component having a molecular weight of 500 or less is 4% by mass, a brittle component as a resin can be reduced, and so-called filming components to be fused and fine particles in a developing machine can be suppressed. As a result, the non-magnetic one-component development system can withstand long-term use, and can be used in the toner replenishment system. From the viewpoint of ease of production, the proportion of components having a molecular weight of 500 or less is preferably 1% by mass or more.

The molecular weight distribution of the polyester resin is measured by GPC as follows. A toner base THF sample in which the column is stabilized in a heat chamber at 40 ° C., THF as a solvent is flowed through the column at this temperature at a flow rate of 1 mL / min, and the sample concentration is adjusted to 0.05 to 0.6% by mass. 200 μL of the solution is injected and measured. The THF sample solution is removed with a 0.45 μm liquid chromatograph filter prior to injection to remove THF insoluble components. In measuring the molecular weight of a toner sample, the molecular weight distribution of the sample can be 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, Pressure Chemical Co. Alternatively, the molecular weights manufactured by Toyo Soda Industry Co., Ltd. are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3. It is preferable to use 9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. Further, it is preferable to use an RI (refractive index) detector as the detector. The presence or absence of the THF-insoluble matter in the binder resin is determined when preparing the THF sample solution for molecular weight distribution measurement. That is, when a 0.45 μm filter unit is attached to the tip of the syringe and the liquid is pushed out of the syringe, it is determined that there is no THF-insoluble matter unless the filter is clogged.

(Coloring agent)
The colorant is not particularly limited and may be appropriately selected from known dyes and pigments according to the purpose. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Red, Lead Red, Cadmium Red, Cad Muum Mercury Red, Antimon Zhu, Permanent Red 4R, PA Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Risor Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oh Lured, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Oxidation Chrome, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Ash Examples include green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, and lithopone.
These may be used individually by 1 type and may use 2 or more types together.
The content of the colorant in the toner material is preferably 0.1 to 50% by mass, and more preferably 1 to 10% by mass.

The colorant may be used as a master batch combined with a resin. The resin is not particularly limited and can be appropriately selected from known ones according to the purpose. For example, styrene or a substituted polymer thereof, styrene copolymer, polymethyl methacrylate, polybutyl methacrylate , Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic hydrocarbon resin, alicyclic Aromatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin, and the like. These may be used individually by 1 type and may use 2 or more types together.
In addition to the binder resin, colorant, and charge control agent, additives, wax, fluidity improver, cleaning improver, magnetic material, metal soap, etc. are added to the toner material as necessary. be able to.

As the inorganic fine particles as the additive, for example, silica, titania, alumina, cerium oxide, strontium titanate, calcium carbonate, magnesium carbonate, calcium phosphate, etc. can be used, and hydrophobized with silicone oil, hexamethyldisilazane, etc. It is more preferable to use treated silica fine particles or titanium oxide subjected to a specific surface treatment.
Examples of the silica fine particles include, for example, Aerosil (product numbers: 130, 200 V, 200 CF, 300, 300 CF, 380, OX50, TT600, MOX80, MOX170, COK84, RX200, RY200, R972, R974, R976, R805, R811, R812, T805, R202, VT222, RX170, RXC, RA200, RA200H, RA200HS, RM50, RY200, REA200 (above, manufactured by Nippon Aerosil Co., Ltd.), HDK (part number: H20, H2000, H3004, H2000 / 4, H2050EP, H2015EP, H3050EP) , KHD50), HVK2150 (above, manufactured by Wacker Chemical Co., Ltd.), Cabogil (Part No .: L-90, LM-130, LM-150, M-5, PTG, MS-55, H- , HS-5, EH-5, LM-150D, M-7D, MS-75D, TS-720, TS-610, TS-530) (or, can be used Cabot Corp.).

The titanium oxide subjected to the special surface treatment is a titanium oxide particle having an aluminum or Al ₂ O ₃ coating and further subjected to a surface treatment with an organic treatment agent, and is formed in at least one of the titanium oxide particles. The aluminum or alumina coating is preferably 0.1 to 2.0% by mass in terms of Al ₂ O ₃ . When the amount is less than 0.1% by mass in terms of Al ₂ O ₃ , the effect is weakened. When the amount exceeds 2.0% by mass in terms of Al ₂ O ₃ , the positive chargeability of aluminum functions and Chargeability may be reduced.

  Further, at least one particle surface of the titanium oxide fine particles on which the aluminum or alumina coating is formed is further at least one of an anionic surfactant, zwitterionic surfactant, silane coupling agent, silicone oil, fatty acid, and fatty acid ester. The surface treatment is preferably performed with a kind of organic treatment agent. Thereby, peeling of the surface treatment agent in the titanium oxide fine particles does not occur even under long-term stress, and a stable negative charging performance can be obtained.

  The mechanism by which peeling of the treatment agent is suppressed by forming an aluminum or alumina coating on the titanium oxide fine particles is not clear, but is presumed as follows. When an aluminum or alumina film is first formed on the surface of the titanium oxide fine particles, the surface charge is + near neutrality because the isoelectric point of alumina is relatively high. When an anionic surfactant, a zwitterionic surfactant, a silane coupling agent, a silicone oil, a fatty acid, or a fatty acid ester is added to the compound in that state, these compounds are oriented and adsorbed to form titanium oxide. The fine particle surface becomes lipophilic. Further, it is presumed that by applying heat, the bonding and the like become stronger, and peeling of the surface treatment agent is suppressed.

  Among these, it is preferable to contain two or more different additives, two or more different average particle sizes are more preferable, and an external additive having an average particle size difference of about 2 to 5 times is included. More preferably. When two or more types of external additives having different particle diameters are not contained, the external additive is rapidly embedded in the toner base material over time, and toner fluidity is rapidly deteriorated. Image unevenness due to a decrease in toner fluidity is likely to occur, and the adhesion to the toner is difficult to increase, so that the toner is easily detached from the toner, causing a photosensitive material scratch and an image blur. If two or more types of external additives with different particle sizes are contained, the large particle size external additive acts as a spacer, preventing the embedding of the small particle size external additive effective in toner fluidity in the toner base Thus, toner fluidity can be maintained. Moreover, although the cause is unknown, the thin layer of the developing carrier over time becomes uniform.

  The addition amount of the additive is preferably 0.1 to 5.0 parts by mass, and more preferably 0.8 to 3.2 parts by mass with respect to 100 parts by mass of the toner base. When the addition amount is less than 0.1 parts by mass, a necessary charge amount may not be obtained. When the addition amount exceeds 5.0 parts by mass, the toner of the external additive is caused by long-term stirring in the developing device. The initial characteristics may not be maintained due to separation from the surface or embedding in the toner particles.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

  The above toner materials are mixed, and the mixture is charged into a melt kneader and melt kneaded. As the melt kneader, for example, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by Casey Kay Co., Ltd., PCM type twin screw extruder manufactured by Ikekai Tekko Co., Ltd. Preferably used. It is important that this melt-kneading is performed under appropriate conditions so as not to cause the molecular chains of the binder resin to be broken. Specifically, the melt-kneading temperature is determined with reference to the softening point of the binder resin. If the temperature is higher than the softening point, cutting is severe, and if the temperature is too low, dispersion may not proceed.

-Crushing process-
The pulverization step is a step of pulverizing the kneaded product obtained in the kneading step.
In this pulverization step, it is preferable that the kneaded material is first coarsely pulverized and then finely pulverized. In this case, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a mechanically rotating rotor and a stator is preferably used.

-Classification process-
The classification step is a step of classifying the pulverized material obtained in the pulverization step to adjust the particles to a predetermined particle size.
The classification can be performed, for example, by removing the fine particle portion by a cyclone, a decanter, centrifugation, or the like.
After the pulverization process is completed, the pulverized product is classified in an air stream by centrifugal force or the like, thereby producing a toner having a predetermined particle diameter, for example, an average particle diameter of 5 to 20 μm.

  When the above pulverization and classification steps are completed, powder (fine powder toner) other than the particles obtained as products obtained in those steps is collected, and a predetermined amount is added to the toner material in the mixing step and the melt-kneading step. It is preferable to repeat the above operation.

Here, the powder (fine powder toner) other than the particles used as the product is generated in the fine particle other than the component used as the product having a desired particle size obtained in the pulverization process after the melt-kneading process and the subsequent classification process. It means fine particles other than the components that become a product having a desired particle size.
The content of the fine toner is 1 to 20% by mass with respect to the toner material, and more preferably 5 to 15 parts by mass. If the amount of the fine toner is less than 1% by mass, the consumption of the fine toner may be reduced, so that it may not be possible to contribute to cost reduction. If the amount exceeds 20% by mass, the cause is not clarified. The agglomeration property of the ink becomes high, which may cause a problem that white streaks are generated.

  In order to improve the fluidity, storage stability, developability, and transferability of the toner, inorganic fine particles such as hydrophobic silica fine powder may be further added to and mixed with the toner manufactured as described above. For mixing the additives, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. In order to change the load history applied to the additive, the additive may be added midway or gradually. In this case, you may change the rotation speed, rolling speed, time, temperature, etc. of a mixer. Also, a strong load may be given first, then a relatively weak load, or vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, and a Henschel mixer. Next, the toner is obtained by passing through a sieve of 250 mesh or more to remove coarse particles and aggregated particles.

  The coloration of the toner is not particularly limited and may be appropriately selected according to the purpose, and may be at least one selected from black toner, cyan toner, magenta toner, and yellow toner. Can be obtained by appropriately selecting the type of the colorant, and is preferably a color toner.

  The toner manufactured by the toner manufacturing method of the present invention may be filled in a toner-containing container described later and mounted on the image forming apparatus as it is. Also, the carrier and toner may be filled in the same container and mounted on the image forming apparatus, but the toner of the present invention is preferable for a non-magnetic one-component replenishment type developing unit that does not use a carrier. Used.

(Developer)
The developer of the present invention comprises the toner of the present invention.
The developer may be a one-component developer or a two-component developer. Although it may be magnetic or non-magnetic, a non-magnetic one-component developer is most preferable from the viewpoint that the apparatus can be reduced in size and can be easily colored.

(Toner container)
The toner-containing container of the present invention contains the toner or the developer of the present invention in a container.
There is no restriction | limiting in particular as said container, It can select suitably from well-known things, For example, what has a toner container main body and a cap etc. are mentioned suitably.
The size, shape, structure, material and the like of the toner container body are not particularly limited and can be appropriately selected according to the purpose. For example, the shape is preferably a cylindrical shape, A spiral unevenness is formed on the surface, the toner as the contents can be transferred to the discharge port side by rotating, and a part or all of the spiral part has a bellows function, etc. Particularly preferred.
The material of the toner container main body is not particularly limited, and those having good dimensional accuracy are preferable. For example, a resin is preferable. Among them, for example, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polychlorinated resin Preferred examples include vinyl resin, polyacrylic acid, polycarbonate resin, ABS resin, polyacetal resin, and the like.
The toner-containing container of the present invention is easy to store and transport, has excellent handleability, and is preferably used for replenishing toner by being detachably attached to the process cartridge and image forming apparatus of the present invention described later. Can do.

When used in a two-component developer, it may be used by mixing with a magnetic carrier, and the magnetic carrier is a ferrite containing a divalent metal such as iron, magnetite, Mn, Zn, Cu, A volume average particle size of 15 to 45 μm is preferred. When the average particle size is less than 15 μm, carrier adhesion is likely to occur on the photosensitive member (1) during development. It is easy to produce. In addition, Cu ferrite containing Zn is preferable because of its high saturation magnetization, but can be appropriately selected according to the process of the image forming apparatus 100. The resin for coating the magnetic carrier is not particularly limited, and examples thereof include silicone resin, styrene-acrylic resin, fluorine-containing resin, and olefin resin. In the manufacturing method, the coating resin may be dissolved in a solvent, sprayed into a fluidized bed and coated on the core, or the resin particles are electrostatically attached to the core particles and then thermally melted for coating. It may be a thing. The thickness of the resin to be coated is 0.05 to 10 μm, preferably 0.2 to 5 μm.
The toner of the present invention is preferably used as a color toner. It is excellent in reproducibility of fine lines and fine dots, is excellent in toner granularity, and is excellent in reproducibility of intermediate colors, so that it is more suitable for use as a color toner for forming a color image.

  The present invention also relates to an image forming apparatus including at least a charging device that uniformly charges the surface of the image carrier, and a charging device that applies charging by applying an alternating electric field and the developer described above. An image forming apparatus including a developing device to be used. FIG. 3 is a schematic diagram showing the configuration of the image forming apparatus of the present invention.

[Image forming apparatus]
Hereinafter, an image forming apparatus using the electrophotographic toner of the present invention or a two-component developer composed of the toner and a carrier will be described.

-Intermediate transfer member-
An embodiment of an intermediate transfer member of a transfer system in the present invention will be described. Around a photosensitive drum (hereinafter referred to as a photosensitive member) (10) as an image carrier, a charging roller (20) as a charging device, an exposure device (30), a cleaning device (60) having a cleaning blade, a static elimination A neutralizing lamp (70) as a device, a developing device (40), and an intermediate transfer member (50) as an intermediate transfer member are provided. The intermediate transfer member (50) is suspended by a plurality of suspension rollers (51), and is configured to run endlessly in the direction of the arrow by a driving unit such as a motor (not shown). A part of the suspension roller (51) also serves as a transfer bias roller for supplying a transfer bias to the intermediate transfer member, and a predetermined transfer bias voltage is applied from a power source (not shown). A cleaning device (90) having a cleaning blade for the intermediate transfer member (50) is also provided. Further, a transfer roller (80) is disposed as a transfer means for transferring the developed image onto the transfer paper (100) as the final transfer material, facing the intermediate transfer body (50), and the transfer roller (80). Is supplied with a transfer bias by a power supply device (not shown). Around the intermediate transfer member (50), a corona charger (52) is provided as a charge applying unit.

  The developing device (40) includes a developing belt (41) as a developer carrying member, a black (hereinafter referred to as Bk) developing unit (45K) and yellow (hereinafter referred to as Yk) arranged around the developing belt (41). Development unit (45Y), magenta (hereinafter referred to as magenta) development unit (45M), and cyan (hereinafter referred to as C) development unit (45C). Further, the developing belt (41) is stretched between a plurality of belt rollers, and is configured to run endlessly in a direction of an arrow by a driving unit such as a motor (not shown), and a contact portion with the photoreceptor (10). Then, it moves at almost the same speed as the photoconductor (10).

Since the configuration of each developing unit is common, the following description will be given only for the Bk developing unit (45K), and the other developing units (45Y), (45M), and (45C) will be described in the figure with the Bk developing unit ( The parts corresponding to those in 45K) are denoted by Y, M, and C after the numbers given to those in the unit, and the description thereof is omitted. The developing unit (45K) includes a developing tank (42K) that contains a high-viscosity, high-concentration liquid developer containing toner particles and a carrier liquid component, and a lower portion that serves as the liquid developer in the developing tank (42K). A drawing roller (43K) disposed so as to be immersed, and a coating roller (44K) for thinning the developer drawn from the drawing roller (43K) and applying it to the developing belt (41) Yes. The application roller (44K) has conductivity, and a predetermined bias is applied from a power source (not shown).
In addition to the apparatus configuration shown in FIG. 3, the apparatus configuration of the image forming apparatus according to the present embodiment includes each color developing unit around one photoconductor (10) as shown in FIG. A device configuration may be provided.

  Next, the operation of the image forming apparatus according to the present embodiment will be described. In FIG. 4, the photosensitive member (10) is uniformly charged by the charging roller (20) while being driven to rotate in the direction of the arrow, and then the reflected light from the document is imaged and projected by an optical system (not shown) by the exposure device (30). Thus, an electrostatic charge image is formed on the photoconductor (10). This electrostatic charge image is developed by the developing device (40) to form a toner image as a visible image. The developer thin layer on the developing belt (41) is peeled off from the belt (41) in a thin layer state by contact with the photoreceptor in the developing region, and a latent image is formed on the photoreceptor (10). Transition to the part. The toner image developed by the developing device (40) is transferred to the intermediate transfer member (50) at a contact portion (primary transfer region) between the photosensitive member (10) and the intermediate transfer member (50) moving at a constant speed. (Primary transfer). When transferring three or four colors to be superimposed, this process is repeated for each color to form a color image on the intermediate transfer member (50).

  The corona charger (52) for applying an electric charge to the superimposed toner image on the intermediate transfer member, the photosensitive member (10) and the intermediate transfer member (in the rotation direction of the intermediate transfer member (50)). 50) on the downstream side of the contact facing portion and the upstream side of the contact facing portion between the intermediate transfer member (50) and the transfer paper (100). Then, the corona charger (52) gives the toner image a true charge having the same polarity as the charging polarity of the toner particles forming the toner image, so that the toner image can be satisfactorily transferred to the transfer paper (100). The toner image is sufficiently charged. The toner image is charged by the corona charger (52) and then transferred onto the transfer paper (100) conveyed in the direction of the arrow from a paper supply unit (not shown) by a transfer bias from the transfer roller (80). Batch transfer (secondary transfer). Thereafter, the transfer paper (100) onto which the toner image has been transferred is separated from the photoreceptor (10) by a separation device (not shown), and after being subjected to a fixing process by a fixing device (not shown), the transfer paper (100) is discharged from the device. On the other hand, the untransferred toner is collected and removed from the photoreceptor (10) after the transfer by the cleaning device (60), and the residual charge is discharged by the discharge lamp (70) in preparation for the next charging.

As described above, the static friction coefficient of the intermediate transfer member is preferably 0.1 to 0.6, more preferably 0.3 to 0.5. The volume resistance of the intermediate transfer member is preferably from several Ωcm to 10 ³ Ωcm. By setting the volume resistance to several Ωcm or more and 10 ³ Ωcm or less, the intermediate transfer member itself is prevented from being charged, and the charge imparted by the charge imparting means is less likely to remain on the intermediate transfer member. Transfer unevenness can be prevented. Further, it is possible to easily apply a transfer bias at the time of secondary transfer.
The material of the intermediate transfer member is not particularly limited, and known materials can be used. An example is shown below. (1) A material having a high Young's modulus (tensile modulus) is used as a single-layer belt. PC (polycarbonate), PVDF (polyvinylidene fluoride), PAT (polyalkylene terephthalate), PC (polycarbonate) / PAT ( Polyalkylene terephthalate) blend material, ETFE (ethylene tetrafluoroethylene copolymer) / PC, ETFE / PAT, PC / PAT blend material, carbon black dispersed thermosetting polyimide, and the like. These single-layer belts having a high Young's modulus have the advantage that the amount of deformation with respect to stress during image formation is small, and registration is not likely to occur particularly during color image formation. (2) A belt having a two- to three-layer structure in which a belt having a high Young's modulus is used as a base layer and a surface layer or an intermediate layer is provided on the outer periphery thereof. Therefore, the line image has a performance capable of preventing the line image from being lost. (3) Belts having a relatively low Young's modulus using rubber and elastomer, and these belts have an advantage that line images are hardly lost due to their softness. In addition, the width of the belt is made larger than that of the drive roll and the tension roll, and the elasticity of the belt ear protruding from the roll is used to prevent meandering, so that a low cost can be realized without the need for ribs or meandering prevention devices. .
Conventionally, fluororesin, polycarbonate resin, polyimide resin, and the like have been used for the intermediate transfer belt, but in recent years, an elastic belt in which the entire belt layer or a part of the belt is an elastic member has been used. The transfer of a color image using a resin belt has the following problems.

A color image is usually formed with four colored toners. On one color image, toner layers of 1 to 4 layers are formed. The toner layer receives pressure by passing through the primary transfer (transfer from the photoreceptor to the intermediate transfer belt) and the secondary transfer (transfer from the intermediate transfer belt to the sheet), and the cohesive force between the toners increases. When the cohesive force between the toners increases, the phenomenon of missing characters in the characters and missing edges in the solid portion image tends to occur. Since the resin belt has high hardness and does not deform according to the toner layer, it is easy to compress the toner layer, and the character dropout phenomenon tends to occur.
Recently, there is an increasing demand for forming full-color images on various papers, for example, Japanese paper, intentionally irregularities, and forming images on paper. However, a paper with poor smoothness is liable to generate toner and voids at the time of transfer, and transfer loss is likely to occur. When the transfer pressure at the secondary transfer portion is increased to improve the adhesion, the condensing power of the toner layer is increased, and the above-described character void is generated.

Therefore, the elastic belt is used for the following purposes when transferring to the sheet. The elastic belt is deformed corresponding to the toner layer and the paper having poor smoothness at the transfer portion. In other words, since the elastic belt deforms following local irregularities, the paper does not have excessive flatness and has good adhesion without excessively increasing the transfer pressure on the toner layer. In contrast, a transfer image with excellent uniformity can be obtained.
The elastic belt resin is polycarbonate, fluororesin (ETFE, PVDF), polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer. Styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (for example, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene- Octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (for example, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid). Acid phenyl copolymer, etc.), styrene -Styrenic resins (monopolymer or copolymer containing styrene or styrene-substituted product) such as methyl α-chloroacrylate copolymer, styrene-acrylonitrile-acrylate ester copolymer, methyl methacrylate resin, methacrylic acid Butyl resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (for example, silicone-modified acrylic resin, vinyl chloride resin-modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, Vinyl chloride-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silica One type or a combination of two or more types selected from the group consisting of carbon resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins and polyvinyl butyral resins, polyamide resins, modified polyphenylene oxide resins and the like can be used. . However, it is a matter of course that the material is not limited to the above materials.

  Elastic rubber and elastomer include butyl rubber, fluorine rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene ter Polymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, ricone rubber, fluororubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber , Selected from the group consisting of thermoplastic elastomers (for example, polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester, fluororesin) It is possible to use one kind or two or more kinds of combinations that. However, it is a matter of course that the material is not limited to the above materials.

There are no particular restrictions on the conductive agent for adjusting the resistance value. For example, carbon black, graphite, metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite Conductive metal oxides such as oxides (ATO) and indium oxide-tin oxide composite oxides (ITO), and conductive metal oxides are coated with insulating fine particles such as barium sulfate, magnesium silicate and calcium carbonate But you can. Of course, the conductive agent is not limited thereto.
The surface layer material and the surface layer are required to prevent contamination of the photoconductor by the elastic material, reduce the surface friction resistance to the transfer belt surface, reduce the adhesion of the toner, and improve the cleaning property and the secondary transfer property. . For example, materials that use one or a combination of two or more of polyurethane, polyester, epoxy resin, etc. to reduce surface energy and increase lubricity, such as fluorine resin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide, etc. These powders and particles can be used by dispersing one type, two or more types, or a combination of particles having different particle sizes. Further, it is also possible to use a material having a surface energy reduced by forming a fluorine-rich layer on the surface by heat treatment, such as a fluorine-based rubber material.

~ Charging device ~
FIG. 5 is a schematic diagram illustrating a configuration of an image forming apparatus using a contact-type charging device. The photosensitive member (140) as the member to be charged and the image carrier is rotationally driven in the direction of the arrow at a predetermined speed (process speed). The charging roller (160), which is a charging member brought into contact with the photosensitive drum, is basically composed of a cored bar and a conductive rubber layer formed concentrically on the outer periphery of the cored bar, and both ends of the cored bar are not shown. In addition to being held freely by a bearing member or the like, the photosensitive drum is pressed with a predetermined pressing force by a pressing means (not shown), and in this case, the charging roller (160) is a photosensitive member (140). Rotates following the rotational drive. The charging roller (160) is formed to have a diameter of 16 mm by coating a medium resistance rubber layer of about 100,000 Ω · cm on a core metal having a diameter of 9 mm.
The cored bar of the charging roller (160) and a power source (not shown) are electrically connected, and a predetermined bias is applied to the charging roller by the power source. As a result, the peripheral surface of the photoreceptor (140) is uniformly charged to a predetermined polarity and potential.
The charging device used in the present invention may of course be non-contact limited to the contact-type charging device as described above. However, since an image forming apparatus with reduced ozone generated from the charging device can be obtained, the contact-type charging device can be obtained. It is preferable to use an apparatus.
Further, in the image forming apparatus of the present invention, an alternating electric field is applied to the charging device. In a DC (direct current) electric field, a large number of O ₃ ⁻ and NO ₃ ⁻ are formed in order to charge the photosensitive member to −polarity. The ozone and nitrogen oxides adhere to the photoreceptor and deteriorate the surface of the photoreceptor. In particular, the surface of the photoconductor is hardened and wear increases, and since the friction coefficient is small, external additives are easily attached and filming often occurs. For this reason, by applying an alternating electric field on which AC (alternating current) is superimposed, generation of ozone or the like can be suppressed and the photosensitive member can be charged uniformly. In particular, by using alternating electric fields, it is possible to suppress deterioration of the photoreceptor with ozone due to generation of reverse polarity H ₃ O ⁺ .

  The shape of the charging member used in the present invention may take any form such as a magnetic brush or a fur brush in addition to the roller, and can be selected according to the specifications and form of the image forming apparatus. In the case of using a magnetic brush, the magnetic brush is composed of various ferrite particles such as Zn—Cu ferrite as a charging member, a non-magnetic conductive sleeve for supporting it, and a magnet roll included therein. In addition, when using a fur brush, for example, as a material of the fur brush, a fur treated with carbon, copper sulfide, metal or metal oxide is used, and this is wound around a metal or other conductive core metal. By charging or pasting, it becomes a charging device.

-Tandem type color image forming device-
FIG. 6 is a schematic diagram showing the configuration of the tandem color image forming apparatus of the present invention.
In the tandem type image forming apparatus, as shown in FIG. 6, the image on each photoconductor (1) is sequentially transferred onto the sheet (s) conveyed by the sheet conveying belt (3) by the transfer device (2). As shown in FIG. 8, the image on each photosensitive member (1) is once transferred to the intermediate transfer member (4) by the primary transfer device (2) and then the intermediate transfer member. (4) There is an indirect transfer type in which the above image is collectively transferred to the sheet (s) by the secondary transfer device (5). The transfer device (5) is a transfer conveyance belt, but there are also roller shapes and methods.
Comparing the direct transfer type and the indirect transfer type, the former is the upstream side of the tandem type image forming apparatus (T) in which the photoconductors (1) are arranged, and the downstream side. Therefore, the fixing device (7) must be arranged on the sheet, and there is a disadvantage that the fixing device (7) is enlarged in the sheet conveying direction. On the other hand, the latter can set the secondary transfer position relatively freely. The sheet feeding device (6) and the fixing device (7) can be arranged so as to overlap the tandem type image forming device (T), and there is an advantage that downsizing is possible.

In the former, in order not to increase the size in the sheet conveyance direction, the fixing device (7) is disposed close to the tandem type image forming apparatus (T). Therefore, the fixing device (7) cannot be disposed with a sufficient margin that the sheet (s) can bend, and an impact (particularly thick sheet) when the leading edge of the sheet (s) enters the fixing device (7). The fixing device (7) has an influence on the upstream side image formation due to the speed difference between the sheet conveying speed when passing through the fixing device (7) and the sheet conveying speed by the transfer conveying belt. There are easy drawbacks. On the other hand, in the latter case, since the fixing device (7) can be disposed with a sufficient margin that the sheet (s) can bend, the fixing device (7) hardly affects the image formation. Can do.
Due to the above, recently, an indirect transfer type among tandem type image forming apparatuses has attracted attention. FIG. 7 is a schematic view showing a configuration of an image forming apparatus having an intermediate transfer member, which is a tandem color image forming apparatus of the present invention.
In this type of color image forming apparatus, as shown in FIG. 7, the transfer residual toner remaining on the photosensitive member (1) after the primary transfer is removed by the photosensitive member cleaning device (8) to remove the photosensitive member ( 1) The surface was cleaned and prepared for another image formation. In addition, the transfer residual toner remaining on the intermediate transfer body 4 after the secondary transfer is removed by the intermediate transfer body cleaning device (9) to clean the surface of the intermediate transfer body (4), thereby preparing for the image formation again. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 8 shows an embodiment of the present invention and is a schematic diagram showing the configuration of a tandem indirect transfer type image forming apparatus. In the figure, reference numeral (100) is a copying apparatus main body, (200) is a paper feed table on which the copying apparatus is mounted, (300) is a scanner mounted on the copying apparatus main body (100), and (400) is an automatic document feeder mounted thereon. (ADF). The copying machine main body (100) is provided with an endless belt-shaped intermediate transfer member (10) in the center.
Then, as shown in FIG. 8, in the illustrated example, it is wound around three support rollers (14), (15) and (16) so as to be able to rotate and convey clockwise in the figure.
In this illustrated example, an intermediate transfer body cleaning device (17) for removing residual toner remaining on the intermediate transfer body (10) after image transfer is provided on the left of the second support roller (15) among the three.
Further, among the three, on the intermediate transfer member (10) stretched between the first support roller (14) and the second support roller (15), yellow, cyan, and magenta are arranged along the transport direction. , Black image forming means (18) are arranged side by side to constitute a tandem image forming apparatus (20).
On the tandem image forming apparatus (20), an exposure apparatus (21) is further provided as shown in FIG. On the other hand, a secondary transfer device (22) is provided on the side opposite to the tandem image forming device (20) with the intermediate transfer member (10) interposed therebetween. In the illustrated example, the secondary transfer device (22) includes a secondary transfer belt (24), which is an endless belt, spanned between two rollers (23), and the second transfer device (22) passes through an intermediate transfer member (10). 3 is pressed against the support roller (16), and the image on the intermediate transfer body (10) is transferred to the sheet.

Next to the secondary transfer device (22), a fixing device (25) for fixing the transferred image on the sheet is provided. The fixing device (25) is configured by pressing a pressure roller (27) against a fixing belt (26) which is an endless belt.
The secondary transfer device (22) described above is also provided with a sheet transport function for transporting the image-transferred sheet to the fixing device (25). Of course, a transfer roller or a non-contact charger may be arranged as the secondary transfer device (22). In such a case, it is difficult to provide this sheet conveying function together.
In the illustrated example, a sheet is placed under such a secondary transfer device (22) and a fixing device (25) so as to record an image on both sides of the sheet in parallel with the tandem image forming device (20). A sheet inverting device (28) for inverting is provided.

Now, when making a copy using this color image forming apparatus, the document is set on the document table (30) of the automatic document feeder (400). Alternatively, the automatic document feeder (400) is opened, a document is set on the contact glass (32) of the scanner (300), and the automatic document feeder (400) is closed and pressed by it.
When a start switch (not shown) is pressed, when the document is set on the automatic document feeder (400), the document is transported and moved onto the contact glass (32), and then the other contact glass (32). When a document is set on the scanner, the scanner (300) is immediately driven to travel on the first traveling body (33) and the second traveling body (34). Then, the first traveling body (33) emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body (34) and is reflected by the mirror of the second traveling body (34). Then, it is put into the reading sensor (36) through the imaging lens (35), and the content of the original is read.
When a start switch (not shown) is pressed, one of the support rollers (14), (15), and (16) is driven to rotate by the drive motor (not shown), and the other two support rollers are driven to rotate. The transfer body (10) is rotated and conveyed. At the same time, the individual image forming means (18) rotates the photoconductor (40) to form black, yellow, magenta and cyan monochrome images on the photoconductor (40), respectively. Then, along with the conveyance of the intermediate transfer body (10), the monochrome images are sequentially transferred to form a composite color image on the intermediate transfer body (10).
On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers (42) of the paper feed table (200) is selectively rotated, and one of paper feed cassettes (44) provided in multiple stages in the paper bank (43). The sheet is fed out from the sheet, separated one by one by a separation roller (45), put into a sheet feeding path (46), and conveyed by a conveying roller (47) to a sheet feeding path (48) in the copying machine main body (100). Guide and stop against the registration roller (49).

Alternatively, the sheet feeding roller (50) is rotated to feed out the sheets on the manual feed tray (51), separated one by one by the separation roller (52), and placed in the manual sheet feeding path (53). ) And stop.
Then, the registration roller (49) is rotated in time with the composite color image on the intermediate transfer member (10), and the sheet is fed between the intermediate transfer member (10) and the secondary transfer device (22). The image is transferred by the next transfer device (22) and a color image is recorded on the sheet.
The sheet after image transfer is conveyed by the secondary transfer device (22) and sent to the fixing device (25). The fixing device (25) applies heat and pressure to fix the transferred image, and then the switching claw. It is switched at (55), discharged by the discharge roller (56), and stacked on the discharge tray (57). Alternatively, it is switched by the switching claw (55) and put into the sheet reversing device (28), where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then the paper discharge tray (56) is discharged by the discharge roller (56). 57) Drain up.

On the other hand, the intermediate transfer member (10) after the image transfer is removed by the intermediate transfer member cleaning device (17) to remove residual toner remaining on the intermediate transfer member (10) after the image transfer. To prepare for image formation again.
Here, the registration roller (49) is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

~ Process cartridge ~
FIG. 9 is a schematic view showing a configuration of a tandem indirect transfer type image forming apparatus including the process cartridge of the present invention. In FIG. 9, (a) shows the entire process cartridge, (b) shows the photosensitive member, (c) shows the charging means, (d) shows the developing means, and (e) shows the cleaning means.
In the present invention, at least the photoreceptor (b) and the developing means (d) among the constituent elements such as the above-mentioned photoreceptor (b), charging device means (c), developing means (d), and cleaning means (e). Are integrally connected as a process cartridge, and the process cartridge is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. Parts indicate parts by weight.

(Developer)
The image forming apparatus of the present invention was used by setting the following conditions using the developing device of FIG.
Line speed 175 (mm / sec)
Photoconductor diameter 30 (mm)
Sleeve / photoreceptor linear speed ratio 1.5
Gp 0.4 (mm)
Gd (Developing roller-Doctor Gap) 0.65 (mm)
Developer pumping amount 60 (mg / cm ² )
Roller diameter φ18 (mm)
Main pole angle 0 °
Main pole magnetic flux density 100 (mT)
Doctor opposite pole magnetic flux density 70 (mT)
Charging potential V0 -450 (V)
Post-exposure potential VL-60 (V)
Development bias VB (DC component) -300 (V)
Development bias VB (AC component)-Square wave-Frequency 2.75 kHz
・ Duty 50%
・ Vpp900V (peak to peak voltage)
The main pole angle is an angle formed by a main pole (a pole indicated by P1 in FIG. 1) with respect to a line segment connecting the center points of the photosensitive member and the developing sleeve. The developing sleeve is formed by cutting a V-shaped groove into an aluminum extrusion. The number of V-grooves is 130 and a right-angle groove having a depth of 65 μm. The developer amount regulating body is a material having rigidity and magnetism. The developer amount regulating body is not limited to a metal material such as iron or stainless steel, but may be composed of a resin material in which magnetic particles such as ferrite and magnetite are blended. Further, the developer amount restricting body itself is not made of a magnetic material, and another member such as a metal plate made of a magnetic material is directly or indirectly fixed to the developer amount restricting body. The effect of can be obtained.

(Evaluation of two-component developer)
Using a ferrite carrier coated with a silicone resin and having an average particle size of 35 μm, 7 parts by weight of each color toner is uniformly mixed and charged using a type of tumbler mixer in which the container rolls and stirs with respect to 100 parts by weight of the carrier. A developer was prepared.

(Example of carrier production)
(Carrier 1)
・ 167 parts of silicone resin solution [solid content 23 wt% (SR2410: manufactured by Toray Dow Corning Silicone)]
・ Aminosilane 0.66 part [Solid content 100% by weight (SH6020: Toray Dow Corning Silicone)]
・ Non-conductive particles 31 parts [Spherical alumina, particle size: 0.35 μm]
-300 parts of toluene was dispersed with a homomixer for 10 minutes to obtain a silicone resin coating film forming solution. Average particle size: 35 μm calcined Mn ferrite powder is used as the core material, and the temperature inside the coater is 40 ° C. by a Spira coater (Okada Seiko Co., Ltd.) so that the coating film forming solution has a film thickness of 0.4 μm on the core material surface. And dried. The obtained carrier was fired in an electric furnace at 300 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 μm, and the particle content: 60% by weight, volume resistivity: 14.1 Log (Ω · cm), magnetization: 68 Am ² / kg [Carrier 1] Got.

For the measurement of the average particle size of the core material, an SRA type of Microtrac particle size analyzer (Nikkiso Co., Ltd.) was used, and the measurement was performed with a range setting of 0.7 [μm] or more and 125 [μm] or less. .
Measurement of the binder resin film thickness of the carrier is made by observing the carrier cross section with a TEM (transmission electron microscope), STEM (scanning transmission electron microscope), etc. after creating the carrier cross section with FIB (focused ion beam) Since the coating film covering the carrier surface can be observed, the average value of the film thickness was used as the film thickness.
Magnetization measurement was performed by the following method using VSM-P7-15 manufactured by Toei Industry Co., Ltd.
About 0.15 g of the sample was weighed, filled in a cell having an inner diameter of 2.4 mmφ and a height of 8.5 mm, and measured under a magnetic field of 1000 oerste (Oe).

(Silica production example)
(Silica 1)
100 g of fine silica powder having a BET specific surface area of 300 m ² / g produced by a gas phase method was put in a reaction vessel, and 2.0 g of water was sprayed with stirring in a nitrogen atmosphere. This was sprayed with 10 g of hexamethyldisilazane, heated and stirred at 150 ° C. for 1 hour, and then cooled. Then, it was crushed by a jet mill to obtain silica particles having a primary average particle diameter of 10 nm. Thereafter, classification was performed with a dry classifier TC-40 II (manufactured by Nissin Engineering Co., Ltd.) to remove aggregates having a particle size of 50 μm or more, and silica 1 was obtained.

(Binder Resin Synthesis Example 1)
-Synthesis of polyester resin a-
In a four-neck separable flask equipped with a stirrer, a thermometer, a nitrogen inlet, a downflow condenser, and a condenser tube, 740 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 300 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 466 g of dimethyl terephthalate, 80 g of isododecenyl succinic anhydride, and 114 g of tri-n-butyl 1,2,4-benzenetricarboxylate It was added along with the esterification catalyst.
Subsequently, it was made to react at 200 degreeC under nitrogen atmosphere for 8 hours, and then it was made to react for 7 hours, stirring at 210 degreeC pressure reduction. As a result, the molecular weight is 500 or less, the content is 2.8%, the molecular weight peak is 6800, the glass transition temperature (Tg) is 58 ° C., the Mw / Mn ratio is 3.8, the acid value is 2.1 KOH mg / g, and the apparent viscosity is 101 Pa · s by a flow tester. A polyester resin a having a temperature of 112 ° C. was synthesized. Moreover, THF insoluble matter was not contained.

<Example 1>
-Production of Toner A-
-Polyester resin a 100 parts by mass-C.I. I. Pigment Blue 15, 3 parts by mass, charge control agent (bis (3,5-di-tert-butylsalicylate-O1, O2) zinc) 2 parts by mass, carnauba wax 5 parts by weight Henschel mixer (Mitsui) Premixed (mixed) using Mining Co., Ltd. FM20C). The mixing conditions were a sufficient mixing by repeating a set of 120 seconds rotation and 60 seconds rotation stop at a peripheral speed of 30 m / sec three times. Thereafter, 10 parts by mass of finely collected toner collected in advance was added, and kneading was performed for 45 minutes with two rolls having a roll surface set at 95 ° C. Thereafter, after rolling and cooling and coarse pulverization, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industry Co., Ltd.) and a wind classifier using a swirling flow (DS classifier: manufactured by Nippon Pneumatic Industry Co., Ltd.) Blue colored particles were obtained.
Thereafter, 100 parts of blue colored particles, 1.5 parts of silica 1 and 0.5 parts of hydrophobized titanium oxide having a primary average particle diameter of 13 nm are mixed with a Henschel mixer (FM20C, Mitsui Mining Co., Ltd.) to obtain a toner. It was. The mixing conditions were a circumferential speed of 30 m / sec, a set of 120 seconds rotation and 60 seconds rotation stop was repeated 5 times and mixed to obtain a toner.
100 parts by weight of carrier 1 with respect to 7 parts by weight of the obtained toner were uniformly mixed and charged using a type of tumbler mixer in which the container was rolled and stirred to prepare a developer. The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Example 2>
In Example 1, evaluation was performed in the same manner as in Example 1 except that the conditions and kneading conditions when the toner material was premixed (mixed) using a Henschel mixer (FM20C manufactured by Mitsui Mining Co., Ltd.) were changed as follows.
Premix conditions were set by repeating a set of rotating for 30 seconds and stopping rotation for 60 seconds twice at a peripheral speed of 23 m / sec. The kneading conditions were such that kneading was performed for 30 minutes with two rolls having a roll surface set at 105 ° C.
The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Example 3>
In Example 1, evaluation was performed in the same manner as in Example 1 except that the conditions and kneading conditions when the toner material was premixed (mixed) using a Henschel mixer (FM20C manufactured by Mitsui Mining Co., Ltd.) were changed as follows.
The mixing conditions were a circumferential speed of 35 m / sec, and a set of 120 second rotation and 60 second rotation stop was repeated 10 times for mixing. The kneading conditions were kneading for 60 minutes with two rolls with the roll surface set at 90 ° C.
The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Example 4>
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the developing gap Gp of the developing device was changed to 0.3 mm. The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Example 5>
In Example 1, evaluation was performed in the same manner as in Example 1 except that the developing gap Gp of the developing device was changed to 0.6 mm. The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Example 6>
In Example 1, a toner was produced and evaluated in the same manner as in Example 1 except that 0.15 part of zinc stearate was mixed at the same time as the mixing of the toner external additive. The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Example 7>
In Example 1, particles having a larger particle size distribution were extracted in the toner pulverization step, and a toner was manufactured and evaluated. The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Comparative Example 1>
In Example 1, evaluation was performed in the same manner as in Example 1 except that the conditions and kneading conditions when the toner material was premixed (mixed) using a Henschel mixer (FM20C manufactured by Mitsui Mining Co., Ltd.) were changed as follows.
Premix conditions were set by rotating a set of 15 seconds rotation and 60 seconds rotation stop twice at a peripheral speed of 18 m / sec. As the kneading conditions, kneading was performed for 20 minutes with two rolls having a roll surface set at 115 ° C.
The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

<Comparative example 2>
In Example 1, evaluation was performed in the same manner as in Example 1 except that the conditions and kneading conditions when the toner material was premixed (mixed) using a Henschel mixer (FM20C manufactured by Mitsui Mining Co., Ltd.) were changed as follows.
The mixing conditions were a circumferential speed of 35 m / sec, and a set of 120 seconds rotation and 60 seconds rotation stop was repeated 20 times for mixing. The kneading conditions were such that the roll surface was kneaded for 60 minutes with two rolls set to 85 ° C., and then again kneaded for 60 minutes with two rolls set to 95 ° C.
The physical properties of the obtained toner and developer are shown in Table 1, and the evaluation results are shown in Table 2.

(Evaluation item)
1) Carrier spent property Chart of 20% image area of developer charge amount (μc / g) after output of 100,000 sheets while controlling toner density so that image density becomes 1.4 ± 0.2 In the amount of change, compared to the initial agent before output, the case of 0 to 30% reduction amount is ◯, the case of 30% to 50% reduction amount is Δ, the case of 50% or more reduction amount is × evaluated. The charge amount was measured by the blow-off method.

2) Developer squeezing property The uniformity of a solid image after outputting 100,000 sheets was evaluated while controlling the toner density so that the image density of the chart of 100% image area was 1.4 ± 0.2. Good developer build-up, solid images that are uniform and good even when compared to offset prints, ◯ for slightly non-uniform images that can withstand use, and apparently uneven uniformity Yes, and those that could not be used were marked with x.

3) Particle size The particle size of the toner was measured using a particle size measuring device “Coulter Counter TAII” manufactured by Coulter Electronics Co., Ltd., with an aperture diameter of 100 μm. The volume average particle diameter and the number average particle diameter were determined by the particle size measuring instrument.

4) Average circularity E
The average circularity E can be measured by a flow type particle image analyzer FPIA-3000 (manufactured by SYSMEX). As a specific measuring method, 0.3 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 120 ml of water from which impure solids have been removed in advance, and about 0.2 g of a measurement sample is further added. Add. The suspension in which the sample is dispersed is obtained by carrying out a dispersion treatment with an ultrasonic disperser for about 2 minutes, and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of about 5000 / μl.

5) Image graininess and sharpness A photographic image was output in a single color, and the degree of graininess and sharpness was visually evaluated. Evaluations were made from GOOD, ◎, ○, Δ, and ×.並 is equivalent to offset printing, ◯ is slightly worse than offset printing, Δ is much worse than offset printing, and × is very bad compared to conventional electrophotographic images.

6) Deterioration fog In an environment of a temperature of 10 ° C. and a humidity of 15%, the toner and the carrier were deteriorated by empty stirring for 1 hour in a developing unit without outputting paper. This state is a compulsory test method that reproduces the phenomenon in which the developer stirs in the actual machine in order to maintain chargeability when printing an image with an extremely small image area or when repeating printing and standby. It will be a severe condition that is extremely stressful.
Thereafter, the developer was used to visually evaluate the degree of toner contamination on the background of the transfer paper after outputting 100 sheets of a 5% image area ratio chart. Evaluations were made from GOOD, ◎, ○, Δ, and ×. ◎ indicates that the toner stain is not observed at all and is in a good state, ○ indicates that the contamination is slightly observed, △ indicates that the contamination is slightly observed, and x indicates that the contamination is not within the allowable range. There is a problem.

7) Toner scattering In an environment of a temperature of 40 ° C. and a humidity of 90%, the toner contamination state in the copying machine after the image area ratio 5% chart continuous 100,000 sheet output durability test was visually evaluated using each toner. ◎ indicates that the toner is not observed at all and is in a good condition. ○ indicates that the slight contamination is observed. There is a problem.

8) Environmental preservability Weigh out 10g of toner, put it in a 20ml glass container, tap the glass bottle 100 times, leave it in a thermostat set at 55 ° C and 80% humidity for 24 hours, The penetration was measured with The toner stored in a low-temperature and low-humidity (10 ° C., 15%) environment was similarly evaluated for penetration, and the value with the smaller penetration was evaluated in a high-temperature and high-humidity and low-temperature and low-humidity environment. From the favorable ones, ◎: 20 mm or more, ◯: 15 mm or more and less than 20 mm, Δ: 10 mm or more to less than 15 mm, x: less than 10 mm.

9) Transferability A developing stress was applied by stirring the developing machine without outputting paper for 60 minutes. Thereafter, the electrostatic image developed with an adhesion amount of 0.4 mg / cm ² on the photoconductor is transferred to paper (Type 6200, manufactured by Ricoh Co., Ltd.) at a transfer current of 15 μA, and the transfer residual toner on the photoconductor is removed. It is transferred to white paper with Scotch tape (manufactured by Sumitomo 3M Co., Ltd.), measured with X-Rite 938 (manufactured by X-Rite), and those whose difference from the blank is less than 0.005 is ◎, 0.005-0 .015 was evaluated as .largecircle., 0.016-0.02 was evaluated as .DELTA., And more than 0.02 was evaluated as x.

10) Evaluation of circularity SF-1 and SF-2 300 toner SEM images obtained by FE-SEM (S-4200) manufactured by Hitachi, Ltd. were randomly sampled, and the image information was sent via the interface. Introduced into an image analysis apparatus (Luzex AP) manufactured by Nireco Corp.

1 is a schematic configuration diagram of a developing device of an image forming apparatus according to an embodiment. FIG. 4 is a diagram schematically illustrating the shape of a toner for explaining the shape factor SF-1 and the shape factor SF-2. 1 is a schematic diagram illustrating a configuration of an image forming apparatus of the present invention. 1 is a schematic diagram illustrating a configuration of an image forming apparatus of the present invention. 1 is a schematic diagram illustrating a configuration of an image forming apparatus using a contact-type charging device. 1 is a schematic diagram showing a configuration of a tandem color image forming apparatus of the present invention. 1 is a schematic diagram illustrating a configuration of an image forming apparatus having an intermediate transfer member, which is a tandem color image forming apparatus of the present invention. 1 is a schematic diagram illustrating a configuration of an image forming apparatus of a tandem type indirect transfer system according to the present invention. 1 is a schematic diagram illustrating a configuration of a tandem indirect transfer type image forming apparatus including a process cartridge of the present invention.

Explanation of symbols

(Figure 1)
DESCRIPTION OF SYMBOLS 1 Developing apparatus 2 Toner hopper 3 Toner flow apparatus 4 Developer accommodating part 5 1st stirring screw 6 2nd stirring screw 7 Developing sleeve 7a Cleaning blade 8 Photoconductor 9 Doctor 10 Power supply 23 Toner supply port

(Fig. 3, 4, 6, 7)
DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Transfer device 3 Sheet conveyance belt 4 Intermediate transfer body 5 Secondary transfer device 6 Paper feed device 7 Fixing device 8 Photoconductor cleaning device 9 Intermediate transfer body cleaning device 10 Photoconductor (photoconductor drum)
20 charging roller 30 exposure device 40 developing device 41 developing belt 42K developing tank 42Y developing tank 42M developing tank 42C developing tank 43K pumping roller 43Y pumping roller 43M pumping roller 43C pumping roller 44K coating roller 44Y coating roller 44C coating roller 44M coating roller 44C Unit 45Y Development unit 45M Development unit 45C Development unit 50 Intermediate transfer member 51 Suspended roller 52 Corona charger 60 Cleaning device 70 Static elimination lamp 80 Transfer roller 90 Cleaning device 100 Transfer paper s Sheet T Tandem type image forming device

(Fig. 5)
140 Photoconductor 160 Charging roller

(Fig. 8)
DESCRIPTION OF SYMBOLS 10 Intermediate transfer body 14, 15, 16 Support roller 17 Intermediate transfer body cleaning apparatus 18 Image formation means 20 Tandem image formation part 21 Exposure apparatus 22 Secondary transfer apparatus (transfer roller)
23 roller 24 secondary transfer belt 25 fixing device 26 fixing belt 27 pressure roller 28 sheet reversing device 30 document table 32 contact glass 33 first traveling member 34 second traveling member 35 imaging lens 36 reading sensor 40 photosensitive member 42 paper feed Roller 43 Paper bank 44 Paper feed cassette 45 Separation roller 46, 48 Paper feed path 47 Transport roller 49 Registration roller 50 Paper feed roller 51 Manual feed tray 52 Separation roller 53 Manual feed path 55 Switching claw 56 Discharge roller 57 Paper discharge tray 100 Copying Machine body 200 Paper feed table 300 Scanner 400 Automatic document feeder

(Fig. 9)
a process cartridge b photoconductor c developing means d charging means e cleaning means

Claims (32)

A toner containing at least a resin, a colorant, and a metal salt of salicylic acid as a charge control agent, and containing by XPS (photoelectron spectroscopy) a metal element derived from the charge control agent on the surface of the toner base particles from which the external additive of the toner is removed A toner for an image forming apparatus, characterized in that the amount is 0.1 to 1.0 atomic% with respect to the total compositional elements on the surface. The dispersion state on the surface of the charge control agent (according to the reflected electron image analysis of FE-SEM) is characterized in that the number% of coarse charge control agent having a diameter of 2 μm or more is 0.1 to 2.0 number%. The toner for an image forming apparatus according to claim 1. The toner for an image forming apparatus according to claim 1, wherein the charge control agent is a salicylic acid zinc salt. 4. The toner for an image forming apparatus according to claim 1, wherein the charge control agent is bis (3,5-di-tert-butyl salicylate-O1, O2) zinc. In a premixed state in which the charge control agent before kneading is dispersed in a resin, at least the charge control agent has a crystal size of 0.1 to 10 μm and sufficiently crushed and mixed. The toner for an image forming apparatus according to claim 1. 6. The toner for an image forming apparatus according to claim 1, wherein the external additive includes at least one selected from metal oxide, metal nitride, and metal carbide. The toner for an image forming apparatus according to any one of claims 1 to 6, wherein the external additive includes at least a titanium oxide having a primary particle number average particle diameter of 5 to 40 nm. 8. The toner for an image forming apparatus according to claim 1, wherein the toner comprises at least a wax having a hydrocarbon straight chain as a releasing agent. The toner for an image forming apparatus according to claim 1, wherein the external additive is dry-mixed together with a mixed medium. The toner for an image forming apparatus according to claim 1, comprising a fatty acid metal salt. The toner for an image forming apparatus according to claim 1, wherein the toner is a color toner. The toner for an image forming apparatus according to claim 1, wherein the toner particles have an average circularity of 0.94 or more and less than 1.00. The toner particles have a volume average particle diameter of 2.0 to 8.0 μm and a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) of 1.00. The toner for an image forming apparatus according to claim 1, wherein the toner is in a range of ˜1.40. 14. The image forming apparatus according to claim 1, wherein the toner particles have SF-1 of 100 to 180 and SF-2 of 100 to 180. Toner. The image forming apparatus has an image carrier that carries an electrostatic latent image on the surface and a magnetic field generating means fixed inside, and carries a two-component developer comprising a magnetic carrier and toner on the surface. A developer carrying member comprising a rotating non-magnetic developing sleeve, and a developing electric field generating means for generating a developing electric field between the image carrying member and the developer carrying member. A developing device for converting the electrostatic latent image into a toner image by the action of the developing electric field using the two-component developer carried on the developer carrying member; The toner for an image forming apparatus according to claim 1, wherein a gap (Gp) between the two is 0.01 mm to 0.7 mm. An image carrier that carries an electrostatic latent image on the surface using at least the toner according to any one of claims 1 to 15, a magnetic carrier that has a magnetic field generating means fixed inside, and a magnetic carrier on the surface; A developer carrying member comprising a non-magnetic developing sleeve carrying a two-component developer made of toner and rotating; and a developing electric field generating means for generating a developing electric field between the image carrier and the developer carrying member. And an image including a developing device that converts the electrostatic latent image on the image carrier into a toner image by the action of the development electric field using toner in a two-component developer carried on the developer carrier. In the image forming apparatus, an interval (Gp) between the image carrier and the developing sleeve is 0.01 mm to 0.7 mm. The image forming apparatus according to claim 16, wherein the carrier has a weight average particle diameter of 15 (μm) to 45 (μm). The image forming apparatus according to claim 16 or 17, wherein the carrier has a resin coating layer on the surface of the core material, and the resin coating layer contains non-conductive particles. The non-conductive particles are carriers containing one or more kinds selected from particles of aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfate, and zirconium oxide having a weight average particle diameter of 5 to 1000 nm. The image forming apparatus according to claim 18. 20. The image forming apparatus according to claim 16, wherein the toner is a toner containing at least one selected from a metal oxide, a metal nitride, and a metal carbide as an external additive. . 21. The image forming apparatus according to claim 16, wherein the toner is a toner containing titanium oxide having at least primary particles having a number average particle diameter of 5 to 40 nm as an external additive. The image forming apparatus according to claim 16, wherein the toner is a toner containing at least a wax having a hydrocarbon straight chain as a release agent. 23. The image forming apparatus according to claim 16, wherein the toner is a toner in which an external additive is dry-mixed together with a mixed medium. The image forming apparatus according to claim 16, wherein the toner is a toner containing a fatty acid metal salt. The image forming apparatus according to any one of claims 16 to 24, wherein the toner is a color toner. 26. The image forming apparatus according to claim 16, wherein the toner particles of the toner are toner having an average circularity of 0.94 or more and less than 1.00. The toner particles of the toner have a volume average particle diameter of 2.0 to 8.0 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1.00 to 1. 27. The image forming apparatus according to claim 16, wherein the toner is in the range of .40. 28. Image formation according to claim 16, wherein the toner particles are toners having SF-1 in the range of 100 to 180 and SF-2 in the range of 100 to 180. apparatus. A latent image carrier that carries a latent image, a charging unit that uniformly charges the surface of the latent image carrier, and the surface of the charged latent image carrier is exposed based on image data, whereby an electrostatic latent image is obtained. An exposure unit for writing, a developing unit for supplying toner to the electrostatic latent image formed on the surface of the latent image carrier and a visible image, and a visible image on the surface of the latent image carrier are transferred to a transfer target The image forming apparatus according to any one of claims 16 to 28, further comprising: a transfer unit that performs fixing, and a fixing unit that fixes the visible image on the transfer target. 30. The image forming apparatus according to claim 16, further comprising a process cartridge that integrally supports the latent image carrier and at least the developing unit and is detachable from the main body of the image forming apparatus. A carrier having at least magnetism, which is used in the image forming apparatus according to claim 16. 30. A developer containing at least a toner and a carrier, which is used in the image forming apparatus according to claim 16.

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